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Sample records for optimized particle filter

  1. Neuromuscular fiber segmentation through particle filtering and discrete optimization

    NASA Astrophysics Data System (ADS)

    Dietenbeck, Thomas; Varray, Franois; Kybic, Jan; Basset, Olivier; Cachard, Christian

    2014-03-01

    We present an algorithm to segment a set of parallel, intertwined and bifurcating fibers from 3D images, targeted for the identification of neuronal fibers in very large sets of 3D confocal microscopy images. The method consists of preprocessing, local calculation of fiber probabilities, seed detection, tracking by particle filtering, global supervised seed clustering and final voxel segmentation. The preprocessing uses a novel random local probability filtering (RLPF). The fiber probabilities computation is performed by means of SVM using steerable filters and the RLPF outputs as features. The global segmentation is solved by discrete optimization. The combination of global and local approaches makes the segmentation robust, yet the individual data blocks can be processed sequentially, limiting memory consumption. The method is automatic but efficient manual interactions are possible if needed. The method is validated on the Neuromuscular Projection Fibers dataset from the Diadem Challenge. On the 15 first blocks present, our method has a 99.4% detection rate. We also compare our segmentation results to a state-of-the-art method. On average, the performances of our method are either higher or equivalent to that of the state-of-the-art method but less user interactions is needed in our approach.

  2. Optimizing Parameters of Process-Based Terrestrial Ecosystem Model with Particle Filter

    NASA Astrophysics Data System (ADS)

    Ito, A.

    2014-12-01

    Present terrestrial ecosystem models still contain substantial uncertainties, as model intercomparison studies have shown, because of poor model constraint by observational data. So, development of advanced methodology of data-model fusion, or data-assimilation, is an important task to reduce the uncertainties and improve model predictability. In this study, I apply the Particle filter (or Sequential Monte Carlo filer) to optimize parameters of a process-based terrestrial ecosystem model (VISIT). The Particle filter is one of the data-assimilation methods, in which probability distribution of model state is approximated by many samples of parameter set (i.e., particle). This is a computationally intensive method and applicable to nonlinear systems; this is an advantage of the method in comparison with other techniques like Ensemble Kalman filter and variational method. At several sites, I used flux measurement data of atmosphere-ecosystem CO2 exchange in sequential and non-sequential manners. In the sequential data assimilation, a time-series data at 30-min or daily steps were used to optimize gas-exchange-related parameters; this method would be also effective to assimilate satellite observational data. On the other hand, in the non-sequential case, annual or long-term mean budget was adjusted to observations; this method would be also effective to assimilate carbon stock data. Although there remain technical issues (e.g., appropriate number of particles and likelihood function), I demonstrate that the Partile filter is an effective method of data-assimilation for process-based models, enhancing collaboration between field and model researchers.

  3. Structural notch filter optimization

    SciTech Connect

    Felton, R.; Burge, S.; Bradshaw, A.

    1995-09-01

    A modified algorithm for nonlinear constrained optimization of structural mode filters for an aeroelastic aircraft model is presented. The optimizer set-up and control is implemented in a MATLAB{trademark} graphical user interface environment. It is shown that the modified algorithm gives improved performance over existing nonlinear constrained optimization methods.

  4. Research on improved mechanism for particle filter

    NASA Astrophysics Data System (ADS)

    Yu, Jinxia; Xu, Jingmin; Tang, Yongli; Zhao, Qian

    2013-03-01

    Based on the analysis of particle filter algorithm, two improved mechanism are studied so as to improve the performance of particle filter. Firstly, hybrid proposal distribution with annealing parameter is studied in order to use current information of the latest observed measurement to optimize particle filter. Then, resampling step in particle filter is improved by two methods which are based on partial stratified resampling (PSR). One is that it uses the optimal idea to improve the weights after implementing PSR, and the other is that it uses the optimal idea to improve the weights before implementing PSR and uses adaptive mutation operation for all particles so as to assure the diversity of particle sets after PSR. At last, the simulations based on single object tracking are implemented, and the performances of the improved mechanism for particle filter are estimated.

  5. Adaptive particle filtering

    NASA Astrophysics Data System (ADS)

    Stevens, Mark R.; Gutchess, Dan; Checka, Neal; Snorrason, Magnús

    2006-05-01

    Image exploitation algorithms for Intelligence, Surveillance and Reconnaissance (ISR) and weapon systems are extremely sensitive to differences between the operating conditions (OCs) under which they are trained and the extended operating conditions (EOCs) in which the fielded algorithms are tested. As an example, terrain type is an important OC for the problem of tracking hostile vehicles from an airborne camera. A system designed to track cars driving on highways and on major city streets would probably not do well in the EOC of parking lots because of the very different dynamics. In this paper, we present a system we call ALPS for Adaptive Learning in Particle Systems. ALPS takes as input a sequence of video images and produces labeled tracks. The system detects moving targets and tracks those targets across multiple frames using a multiple hypothesis tracker (MHT) tightly coupled with a particle filter. This tracker exploits the strengths of traditional MHT based tracking algorithms by directly incorporating tree-based hypothesis considerations into the particle filter update and resampling steps. We demonstrate results in a parking lot domain tracking objects through occlusions and object interactions.

  6. Optimal filtering and filter stability of linear stochastic delay systems

    NASA Technical Reports Server (NTRS)

    Kwong, R. H.-S.; Willsky, A. S.

    1977-01-01

    Optimal filtering equations are obtained for very general linear stochastic delay systems. Stability of the optimal filter is studied in the case where there are no delays in the observations. Using the duality between linear filtering and control, asymptotic stability of the optimal filter is proved. Finally, the cascade of the optimal filter and the deterministic optimal quadratic control system is shown to be asymptotically stable as well.

  7. Optimization of integrated polarization filters.

    PubMed

    Gagnon, Denis; Dumont, Joey; Déziel, Jean-Luc; Dubé, Louis J

    2014-10-01

    This study reports on the design of small footprint, integrated polarization filters based on engineered photonic lattices. Using a rods-in-air lattice as a basis for a TE filter and a holes-in-slab lattice for the analogous TM filter, we are able to maximize the degree of polarization of the output beams up to 98% with a transmission efficiency greater than 75%. The proposed designs allow not only for logical polarization filtering, but can also be tailored to output an arbitrary transverse beam profile. The lattice configurations are found using a recently proposed parallel tabu search algorithm for combinatorial optimization problems in integrated photonics. PMID:25360980

  8. OPTIMIZATION OF ADVANCED FILTER SYSTEMS

    SciTech Connect

    R.A. Newby; G.J. Bruck; M.A. Alvin; T.E. Lippert

    1998-04-30

    Reliable, maintainable and cost effective hot gas particulate filter technology is critical to the successful commercialization of advanced, coal-fired power generation technologies, such as IGCC and PFBC. In pilot plant testing, the operating reliability of hot gas particulate filters have been periodically compromised by process issues, such as process upsets and difficult ash cake behavior (ash bridging and sintering), and by design issues, such as cantilevered filter elements damaged by ash bridging, or excessively close packing of filtering surfaces resulting in unacceptable pressure drop or filtering surface plugging. This test experience has focused the issues and has helped to define advanced hot gas filter design concepts that offer higher reliability. Westinghouse has identified two advanced ceramic barrier filter concepts that are configured to minimize the possibility of ash bridge formation and to be robust against ash bridges should they occur. The ''inverted candle filter system'' uses arrays of thin-walled, ceramic candle-type filter elements with inside-surface filtering, and contains the filter elements in metal enclosures for complete separation from ash bridges. The ''sheet filter system'' uses ceramic, flat plate filter elements supported from vertical pipe-header arrays that provide geometry that avoids the buildup of ash bridges and allows free fall of the back-pulse released filter cake. The Optimization of Advanced Filter Systems program is being conducted to evaluate these two advanced designs and to ultimately demonstrate one of the concepts in pilot scale. In the Base Contract program, the subject of this report, Westinghouse has developed conceptual designs of the two advanced ceramic barrier filter systems to assess their performance, availability and cost potential, and to identify technical issues that may hinder the commercialization of the technologies. A plan for the Option I, bench-scale test program has also been developed based on the issues identified. The two advanced barrier filter systems have been found to have the potential to be significantly more reliable and less expensive to operate than standard ceramic candle filter system designs. Their key development requirements are the assessment of the design and manufacturing feasibility of the ceramic filter elements, and the small-scale demonstration of their conceptual reliability and availability merits.

  9. Particle Swarm Optimization

    NASA Technical Reports Server (NTRS)

    Venter, Gerhard; Sobieszczanski-Sobieski Jaroslaw

    2002-01-01

    The purpose of this paper is to show how the search algorithm known as particle swarm optimization performs. Here, particle swarm optimization is applied to structural design problems, but the method has a much wider range of possible applications. The paper's new contributions are improvements to the particle swarm optimization algorithm and conclusions and recommendations as to the utility of the algorithm, Results of numerical experiments for both continuous and discrete applications are presented in the paper. The results indicate that the particle swarm optimization algorithm does locate the constrained minimum design in continuous applications with very good precision, albeit at a much higher computational cost than that of a typical gradient based optimizer. However, the true potential of particle swarm optimization is primarily in applications with discrete and/or discontinuous functions and variables. Additionally, particle swarm optimization has the potential of efficient computation with very large numbers of concurrently operating processors.

  10. Particle flow for nonlinear filters with log-homotopy

    NASA Astrophysics Data System (ADS)

    Daum, Fred; Huang, Jim

    2008-04-01

    We describe a new nonlinear filter that is vastly superior to the classic particle filter. In particular, the computational complexity of the new filter is many orders of magnitude less than the classic particle filter with optimal estimation accuracy for problems with dimension greater than 2 or 3. We consider nonlinear estimation problems with dimensions varying from 1 to 20 that are smooth and fully coupled (i.e. dense not sparse). The new filter implements Bayes' rule using particle flow rather than with a pointwise multiplication of two functions; this avoids one of the fundamental and well known problems in particle filters, namely "particle collapse" as a result of Bayes' rule. We use a log-homotopy to derive the ODE that describes particle flow. This paper was written for normal engineers, who do not have homotopy for breakfast.

  11. Distributed SLAM Using Improved Particle Filter for Mobile Robot Localization

    PubMed Central

    Pei, Fujun; Wu, Mei; Zhang, Simin

    2014-01-01

    The distributed SLAM system has a similar estimation performance and requires only one-fifth of the computation time compared with centralized particle filter. However, particle impoverishment is inevitably because of the random particles prediction and resampling applied in generic particle filter, especially in SLAM problem that involves a large number of dimensions. In this paper, particle filter use in distributed SLAM was improved in two aspects. First, we improved the important function of the local filters in particle filter. The adaptive values were used to replace a set of constants in the computational process of importance function, which improved the robustness of the particle filter. Second, an information fusion method was proposed by mixing the innovation method and the number of effective particles method, which combined the advantages of these two methods. And this paper extends the previously known convergence results for particle filter to prove that improved particle filter converges to the optimal filter in mean square as the number of particles goes to infinity. The experiment results show that the proposed algorithm improved the virtue of the DPF-SLAM system in isolate faults and enabled the system to have a better tolerance and robustness. PMID:24883362

  12. Particle Swarm Optimization Toolbox

    NASA Technical Reports Server (NTRS)

    Grant, Michael J.

    2010-01-01

    The Particle Swarm Optimization Toolbox is a library of evolutionary optimization tools developed in the MATLAB environment. The algorithms contained in the library include a genetic algorithm (GA), a single-objective particle swarm optimizer (SOPSO), and a multi-objective particle swarm optimizer (MOPSO). Development focused on both the SOPSO and MOPSO. A GA was included mainly for comparison purposes, and the particle swarm optimizers appeared to perform better for a wide variety of optimization problems. All algorithms are capable of performing unconstrained and constrained optimization. The particle swarm optimizers are capable of performing single and multi-objective optimization. The SOPSO and MOPSO algorithms are based on swarming theory and bird-flocking patterns to search the trade space for the optimal solution or optimal trade in competing objectives. The MOPSO generates Pareto fronts for objectives that are in competition. A GA, based on Darwin evolutionary theory, is also included in the library. The GA consists of individuals that form a population in the design space. The population mates to form offspring at new locations in the design space. These offspring contain traits from both of the parents. The algorithm is based on this combination of traits from parents to hopefully provide an improved solution than either of the original parents. As the algorithm progresses, individuals that hold these optimal traits will emerge as the optimal solutions. Due to the generic design of all optimization algorithms, each algorithm interfaces with a user-supplied objective function. This function serves as a "black-box" to the optimizers in which the only purpose of this function is to evaluate solutions provided by the optimizers. Hence, the user-supplied function can be numerical simulations, analytical functions, etc., since the specific detail of this function is of no concern to the optimizer. These algorithms were originally developed to support entry trajectory and guidance design for the Mars Science Laboratory mission but may be applied to any optimization problem.

  13. The Rao-Blackwellized Particle Filter: A Filter Bank Implementation

    NASA Astrophysics Data System (ADS)

    Hendeby, Gustaf; Karlsson, Rickard; Gustafsson (Eurasipmember), Fredrik

    2010-12-01

    For computational efficiency, it is important to utilize model structure in particle filtering. One of the most important cases occurs when there exists a linear Gaussian substructure, which can be efficiently handled by Kalman filters. This is the standard formulation of the Rao-Blackwellized particle filter (RBPF). This contribution suggests an alternative formulation of this well-known result that facilitates reuse of standard filtering components and which is also suitable for object-oriented programming. Our RBPF formulation can be seen as a Kalman filter bank with stochastic branching and pruning.

  14. System and Apparatus for Filtering Particles

    NASA Technical Reports Server (NTRS)

    Agui, Juan H. (Inventor); Vijayakumar, Rajagopal (Inventor)

    2015-01-01

    A modular pre-filtration apparatus may be beneficial to extend the life of a filter. The apparatus may include an impactor that can collect a first set of particles in the air, and a scroll filter that can collect a second set of particles in the air. A filter may follow the pre-filtration apparatus, thus causing the life of the filter to be increased.

  15. Fully optimal filter for ALLEGRO

    NASA Astrophysics Data System (ADS)

    Santostasi, Giovanni

    2004-03-01

    The FAST and SLOW filters are compared when applied to data from one-mode and two-mode resonant gravitational wave detectors. There is no substantial difference between the performance of two filters in the case of the one-mode detector. Notable reduction of the noise temperature is achieved for a two-mode detector when filtering the data with the FAST filter. We explain the principal reason for the better performance of the FAST filter with respect to the SLOW filter. We also observed that the performance of the FAST filter depends on the ratio Γ between the thermal narrow band noise and the SQUID amplifier white noise.

  16. OPTIMIZATION OF ADVANCED FILTER SYSTEMS

    SciTech Connect

    R.A. Newby; M.A. Alvin; G.J. Bruck; T.E. Lippert; E.E. Smeltzer; M.E. Stampahar

    2002-06-30

    Two advanced, hot gas, barrier filter system concepts have been proposed by the Siemens Westinghouse Power Corporation to improve the reliability and availability of barrier filter systems in applications such as PFBC and IGCC power generation. The two hot gas, barrier filter system concepts, the inverted candle filter system and the sheet filter system, were the focus of bench-scale testing, data evaluations, and commercial cost evaluations to assess their feasibility as viable barrier filter systems. The program results show that the inverted candle filter system has high potential to be a highly reliable, commercially successful, hot gas, barrier filter system. Some types of thin-walled, standard candle filter elements can be used directly as inverted candle filter elements, and the development of a new type of filter element is not a requirement of this technology. Six types of inverted candle filter elements were procured and assessed in the program in cold flow and high-temperature test campaigns. The thin-walled McDermott 610 CFCC inverted candle filter elements, and the thin-walled Pall iron aluminide inverted candle filter elements are the best candidates for demonstration of the technology. Although the capital cost of the inverted candle filter system is estimated to range from about 0 to 15% greater than the capital cost of the standard candle filter system, the operating cost and life-cycle cost of the inverted candle filter system is expected to be superior to that of the standard candle filter system. Improved hot gas, barrier filter system availability will result in improved overall power plant economics. The inverted candle filter system is recommended for continued development through larger-scale testing in a coal-fueled test facility, and inverted candle containment equipment has been fabricated and shipped to a gasifier development site for potential future testing. Two types of sheet filter elements were procured and assessed in the program through cold flow and high-temperature testing. The Blasch, mullite-bonded alumina sheet filter element is the only candidate currently approaching qualification for demonstration, although this oxide-based, monolithic sheet filter element may be restricted to operating temperatures of 538 C (1000 F) or less. Many other types of ceramic and intermetallic sheet filter elements could be fabricated. The estimated capital cost of the sheet filter system is comparable to the capital cost of the standard candle filter system, although this cost estimate is very uncertain because the commercial price of sheet filter element manufacturing has not been established. The development of the sheet filter system could result in a higher reliability and availability than the standard candle filter system, but not as high as that of the inverted candle filter system. The sheet filter system has not reached the same level of development as the inverted candle filter system, and it will require more design development, filter element fabrication development, small-scale testing and evaluation before larger-scale testing could be recommended.

  17. Optimal frequency domain textural edge detection filter

    NASA Technical Reports Server (NTRS)

    Townsend, J. K.; Shanmugan, K. S.; Frost, V. S.

    1985-01-01

    An optimal frequency domain textural edge detection filter is developed and its performance evaluated. For the given model and filter bandwidth, the filter maximizes the amount of output image energy placed within a specified resolution interval centered on the textural edge. Filter derivation is based on relating textural edge detection to tonal edge detection via the complex low-pass equivalent representation of narrowband bandpass signals and systems. The filter is specified in terms of the prolate spheroidal wave functions translated in frequency. Performance is evaluated using the asymptotic approximation version of the filter. This evaluation demonstrates satisfactory filter performance for ideal and nonideal textures. In addition, the filter can be adjusted to detect textural edges in noisy images at the expense of edge resolution.

  18. Westinghouse advanced particle filter system

    SciTech Connect

    Lippert, T.E.; Bruck, G.J.; Sanjana, Z.N.; Newby, R.A.

    1994-10-01

    Integrated Gasification Combined Cycles (IGCC) and Pressurized Fluidized Bed Combustion (PFBC) are being developed and demonstrated for commercial, power generation application. Hot gas particulate filters are key components for the successful implementation of IGCC and PFBC in power generation gas turbine cycles. The objective of this work is to develop and qualify through analysis and testing a practical hot gas ceramic barrier filter system that meets the performance and operational requirements of PFBC and IGCC systems. This paper updates the assessment of the Westinghouse hot gas filter design based on ongoing testing and analysis. Results are summarized from recent computational fluid dynamics modeling of the plenum flow during back pulse, analysis of candle stressing under cleaning and process transient conditions and testing and analysis to evaluate potential flow induced candle vibration.

  19. Resource management in particle filtering for multiple object tracking

    NASA Astrophysics Data System (ADS)

    Pan, Pan; Schonfeld, Dan

    2008-01-01

    This paper presents a novel particle allocation approach to particle filtering for multiple object tracking which minimizes the total tracking distortion given a fixed number of particles over a video sequence. Under the framework of distributed multiple object tracking, we propose the dynamic proposal variance and optimal particle number allocation algorithm for multi-object tracking to allocate particles among multiple targets as well as multiple frames. Experimental results show the superior performance of our proposed algorithm to traditional particle allocation methods, i.e. a fixed number of particles for each object in each frame. To the best of our knowledge, our approach is the first to provide an optimal allocation of a fixed number of particles among multiple objects and multiple frames.

  20. Depth Filters Containing Diatomite Achieve More Efficient Particle Retention than Filters Solely Containing Cellulose Fibers.

    PubMed

    Buyel, Johannes F; Gruchow, Hannah M; Fischer, Rainer

    2015-01-01

    The clarification of biological feed stocks during the production of biopharmaceutical proteins is challenging when large quantities of particles must be removed, e.g., when processing crude plant extracts. Single-use depth filters are often preferred for clarification because they are simple to integrate and have a good safety profile. However, the combination of filter layers must be optimized in terms of nominal retention ratings to account for the unique particle size distribution in each feed stock. We have recently shown that predictive models can facilitate filter screening and the selection of appropriate filter layers. Here we expand our previous study by testing several filters with different retention ratings. The filters typically contain diatomite to facilitate the removal of fine particles. However, diatomite can interfere with the recovery of large biopharmaceutical molecules such as virus-like particles and aggregated proteins. Therefore, we also tested filtration devices composed solely of cellulose fibers and cohesive resin. The capacities of both filter types varied from 10 to 50 L m(-2) when challenged with tobacco leaf extracts, but the filtrate turbidity was ~500-fold lower (~3.5 NTU) when diatomite filters were used. We also tested pre-coat filtration with dispersed diatomite, which achieved capacities of up to 120 L m(-2) with turbidities of ~100 NTU using bulk plant extracts, and in contrast to the other depth filters did not require an upstream bag filter. Single pre-coat filtration devices can thus replace combinations of bag and depth filters to simplify the processing of plant extracts, potentially saving on time, labor and consumables. The protein concentrations of TSP, DsRed and antibody 2G12 were not affected by pre-coat filtration, indicating its general applicability during the manufacture of plant-derived biopharmaceutical proteins. PMID:26734037

  1. Depth Filters Containing Diatomite Achieve More Efficient Particle Retention than Filters Solely Containing Cellulose Fibers

    PubMed Central

    Buyel, Johannes F.; Gruchow, Hannah M.; Fischer, Rainer

    2015-01-01

    The clarification of biological feed stocks during the production of biopharmaceutical proteins is challenging when large quantities of particles must be removed, e.g., when processing crude plant extracts. Single-use depth filters are often preferred for clarification because they are simple to integrate and have a good safety profile. However, the combination of filter layers must be optimized in terms of nominal retention ratings to account for the unique particle size distribution in each feed stock. We have recently shown that predictive models can facilitate filter screening and the selection of appropriate filter layers. Here we expand our previous study by testing several filters with different retention ratings. The filters typically contain diatomite to facilitate the removal of fine particles. However, diatomite can interfere with the recovery of large biopharmaceutical molecules such as virus-like particles and aggregated proteins. Therefore, we also tested filtration devices composed solely of cellulose fibers and cohesive resin. The capacities of both filter types varied from 10 to 50 L m−2 when challenged with tobacco leaf extracts, but the filtrate turbidity was ~500-fold lower (~3.5 NTU) when diatomite filters were used. We also tested pre–coat filtration with dispersed diatomite, which achieved capacities of up to 120 L m−2 with turbidities of ~100 NTU using bulk plant extracts, and in contrast to the other depth filters did not require an upstream bag filter. Single pre-coat filtration devices can thus replace combinations of bag and depth filters to simplify the processing of plant extracts, potentially saving on time, labor and consumables. The protein concentrations of TSP, DsRed and antibody 2G12 were not affected by pre-coat filtration, indicating its general applicability during the manufacture of plant-derived biopharmaceutical proteins. PMID:26734037

  2. Deformable target tracking via particle filter

    NASA Astrophysics Data System (ADS)

    Wang, Junqing; Shi, Zelin; Huang, Shabai

    2005-10-01

    We propose an algorithm, which tracks a deformable object in complex scene based on Bayesian estimation in Particle filter framework. In Particle filter framework, both dynamic model and measure model of Particle filter, which utilizes information of structure of target edges and gray level distribution of neighbors of target edges, are respectively constructed in term of interframe correlation in the context of object tracking. The fuzzy metric is constructed to measure the similarity between histograms of template and candidate sub-regions. The tracking window can be adaptively changed with the variation of object appearance. The strategy for template update is applied according to confidence level threshold. Both judgement of occlusion and solution to occlusion are given in term of threshold and temporal window. Those experimental results illustrate that this algorithm can stably track deformable target under complex background at the low computing cost.

  3. Testing particle filters on convective scale dynamics

    NASA Astrophysics Data System (ADS)

    Haslehner, Mylene; Craig, George. C.; Janjic, Tijana

    2014-05-01

    Particle filters have been developed in recent years to deal with highly nonlinear dynamics and non Gaussian error statistics that also characterize data assimilation on convective scales. In this work we explore the use of the efficient particle filter (P.v. Leeuwen, 2011) for convective scale data assimilation application. The method is tested in idealized setting, on two stochastic models. The models were designed to reproduce some of the properties of convection, for example the rapid development and decay of convective clouds. The first model is a simple one-dimensional, discrete state birth-death model of clouds (Craig and Würsch, 2012). For this model, the efficient particle filter that includes nudging the variables shows significant improvement compared to Ensemble Kalman Filter and Sequential Importance Resampling (SIR) particle filter. The success of the combination of nudging and resampling, measured as RMS error with respect to the 'true state', is proportional to the nudging intensity. Significantly, even a very weak nudging intensity brings notable improvement over SIR. The second model is a modified version of a stochastic shallow water model (Würsch and Craig 2013), which contains more realistic dynamical characteristics of convective scale phenomena. Using the efficient particle filter and different combination of observations of the three field variables (wind, water 'height' and rain) allows the particle filter to be evaluated in comparison to a regime where only nudging is used. Sensitivity to the properties of the model error covariance is also considered. Finally, criteria are identified under which the efficient particle filter outperforms nudging alone. References: Craig, G. C. and M. Würsch, 2012: The impact of localization and observation averaging for convective-scale data assimilation in a simple stochastic model. Q. J. R. Meteorol. Soc.,139, 515-523. Van Leeuwen, P. J., 2011: Efficient non-linear data assimilation in geophysical fluid dynamics. - Computers and Fluids, doi:10,1016/j.compfluid.2010.11.011, 1096 2011. Würsch, M. and G. C. Craig, 2013: A simple dynamical model of cumulus convection for data assimilation research, submitted to Met. Zeitschrift.

  4. Optimal filtering of constant velocity torque data.

    PubMed

    Murray, D A

    1986-12-01

    The purpose of this investigation was to implement an optimal filtering strategy for processing in vivo dynamometric data. The validity of employing commonly accepted analog smoothing methods was also appraised. An inert gravitational model was used to assess the filtering requirements of two Cybex II constant velocity dynamometers at 10 pre-set speeds with three selected loads. Speed settings were recorded as percentages of the servomechanism's maximum tachometer feedback voltage (10 to 100% Vfb max). Spectral analyses of unsmoothed torque and associated angular displacement curves, followed by optimized low-pass digital filtering, revealed the presence of two superimposed contaminating influences: a damped oscillation, representing successive sudden braking and releasing of the servomechanism control system; a relatively stationary oscillatory series, which was attributed to the Cybex motor. The optimal cutoff frequency for any data set was principally a positive function of % Vfb max. This association was represented for each machine by a different, but reliable, third order least-squares polynomial, which could be used to accurately predict the correct smoothing required for any speed setting. Unacceptable errors may be induced, especially when measuring peak torques, if data are inappropriately filtered. Over-smoothing disguises inertial artefacts. The use of Cybex recorder damping settings should be discouraged. Optimal filtering is a minimal requirement of valid data processing. PMID:3784873

  5. Assignment-based particle labeling for PHD particle filter

    NASA Astrophysics Data System (ADS)

    Danu, Daniel G.; Lang, Thomas; Kirubarajan, Thia

    2009-08-01

    The probability hypothesis density (PHD) filter is an estimator that approximates, on a given scenario, the multitarget distribution through its first-order multitarget moment. This paper presents two particles labeling algorithms for the PHD particle filter, through which the information on individual targets identity (otherwise hidden within the first-order multitarget moment) is revealed and propagated over time. By maintaining all particles labeled at any time, the individual target distribution estimates are obtained under the form of labeled particle clouds, within the estimated PHD. The partitioning of the PHD into distinct clouds, through labeling, provides over time information on confirmed tracks identity, tracks undergoing initiation or deletion at a given time frame, and clutter regions, otherwise not available in a regular PHD (or track-labeled PHD). Both algorithms imply particles tagging since their inception, in the measurements sampling step, and their re-tagging once they are merged into particle clouds of already confirmed tracks, or are merged for the purpose of initializing new tracks. Particles of a confirmed track cloud preserve their labels over time frames. Two data associations are involved in labels management; one assignment merges measurement clouds into particle clouds of already confirmed tracks, while the following 2D-assignment associates particle clouds corresponding to non-confirmed tracks over two frames, for track initiation. The algorithms are presented on a scenario containing two targets with close and crossing trajectories, with the particle labeled PHD filter tracking under measurement origin uncertainty due to observations variance and clutter.

  6. Efficient particle filter and its application in contour tracking

    NASA Astrophysics Data System (ADS)

    Chen, Peng; Qian, Hui; Gao, Weisong; Zhu, Miaoliang

    2009-10-01

    In order to improve the real-time performance of particle filter, this paper proposes an efficient particle filter algorithm and evaluates its usage in object contour tracking application. This new filter uses only one particle to predict next state in certain situations. As particle set size is one, there is no need to resample the particles before prediction. Therefore the real-time performance of particle filter is improved. To maintain the performance of particle filter, we use one particle sample only in prediction step and only in situations where particles are close enough with each other. After prediction step, the original number of particle samples is recovered. Experiment shows that the new particle filter uses less time to process the particles while retain tracking performance comparable with the regular particle filter.

  7. Desensitized Optimal Filtering and Sensor Fusion Toolkit

    NASA Technical Reports Server (NTRS)

    Karlgaard, Christopher D.

    2015-01-01

    Analytical Mechanics Associates, Inc., has developed a software toolkit that filters and processes navigational data from multiple sensor sources. A key component of the toolkit is a trajectory optimization technique that reduces the sensitivity of Kalman filters with respect to model parameter uncertainties. The sensor fusion toolkit also integrates recent advances in adaptive Kalman and sigma-point filters for non-Gaussian problems with error statistics. This Phase II effort provides new filtering and sensor fusion techniques in a convenient package that can be used as a stand-alone application for ground support and/or onboard use. Its modular architecture enables ready integration with existing tools. A suite of sensor models and noise distribution as well as Monte Carlo analysis capability are included to enable statistical performance evaluations.

  8. MEDOF - MINIMUM EUCLIDEAN DISTANCE OPTIMAL FILTER

    NASA Technical Reports Server (NTRS)

    Barton, R. S.

    1994-01-01

    The Minimum Euclidean Distance Optimal Filter program, MEDOF, generates filters for use in optical correlators. The algorithm implemented in MEDOF follows theory put forth by Richard D. Juday of NASA/JSC. This program analytically optimizes filters on arbitrary spatial light modulators such as coupled, binary, full complex, and fractional 2pi phase. MEDOF optimizes these modulators on a number of metrics including: correlation peak intensity at the origin for the centered appearance of the reference image in the input plane, signal to noise ratio including the correlation detector noise as well as the colored additive input noise, peak to correlation energy defined as the fraction of the signal energy passed by the filter that shows up in the correlation spot, and the peak to total energy which is a generalization of PCE that adds the passed colored input noise to the input image's passed energy. The user of MEDOF supplies the functions that describe the following quantities: 1) the reference signal, 2) the realizable complex encodings of both the input and filter SLM, 3) the noise model, possibly colored, as it adds at the reference image and at the correlation detection plane, and 4) the metric to analyze, here taken to be one of the analytical ones like SNR (signal to noise ratio) or PCE (peak to correlation energy) rather than peak to secondary ratio. MEDOF calculates filters for arbitrary modulators and a wide range of metrics as described above. MEDOF examines the statistics of the encoded input image's noise (if SNR or PCE is selected) and the filter SLM's (Spatial Light Modulator) available values. These statistics are used as the basis of a range for searching for the magnitude and phase of k, a pragmatically based complex constant for computing the filter transmittance from the electric field. The filter is produced for the mesh points in those ranges and the value of the metric that results from these points is computed. When the search is concluded, the values of amplitude and phase for the k whose metric was largest, as well as consistency checks, are reported. A finer search can be done in the neighborhood of the optimal k if desired. The filter finally selected is written to disk in terms of drive values, not in terms of the filter's complex transmittance. Optionally, the impulse response of the filter may be created to permit users to examine the response for the features the algorithm deems important to the recognition process under the selected metric, limitations of the filter SLM, etc. MEDOF uses the filter SLM to its greatest potential, therefore filter competence is not compromised for simplicity of computation. MEDOF is written in C-language for Sun series computers running SunOS. With slight modifications, it has been implemented on DEC VAX series computers using the DEC-C v3.30 compiler, although the documentation does not currently support this platform. MEDOF can also be compiled using Borland International Inc.'s Turbo C++ v1.0, but IBM PC memory restrictions greatly reduce the maximum size of the reference images from which the filters can be calculated. MEDOF requires a two dimensional Fast Fourier Transform (2DFFT). One 2DFFT routine which has been used successfully with MEDOF is a routine found in "Numerical Recipes in C: The Art of Scientific Programming," which is available from Cambridge University Press, New Rochelle, NY 10801. The standard distribution medium for MEDOF is a .25 inch streaming magnetic tape cartridge (Sun QIC-24) in UNIX tar format. MEDOF was developed in 1992-1993.

  9. A modified PSO based particle filter algorithm for object tracking

    NASA Astrophysics Data System (ADS)

    Tang, Yufei; Fu, Siyao; Tang, Bo; He, Haibo

    2013-05-01

    In this paper, a modified particle swarm optimization (PSO) approach, particle swarm optimization with ɛ- greedy exploration ɛPSO), is used to tackle the object tracking. In the modified ɛPSO algorithm, the cooperative learning mechanism among individuals has been introduced, namely, particles not only adjust its own flying speed according to itself and the best individual of the swarm but also learn from other best individuals according to certain probability. This kind of biologically-inspired mutual-learning behavior can help to find the global optimum solution with better convergence speed and accuracy. The ɛPSO algorithm has been tested on benchmark function and demonstrated its effectiveness in high-dimension multi-modal optimization. In addition to the standard benchmark study, we also combined our new ɛPSO approach with the traditional particle filter (PF) algorithm on the object tracking task, such as car tracking in complex environment. Comparative studies between our ɛPSO combined PF algorithm with those of existing techniques, such as the particle filter (PF) and classic PSO combined PF will be used to verify and validate the performance of our approach.

  10. Covariance Tracking via Geometric Particle Filtering

    NASA Astrophysics Data System (ADS)

    Liu, Yunpeng; Li, Guangwei; Shi, Zelin

    2010-12-01

    Region covariance descriptor recently proposed has been approved robust and elegant to describe a region of interest, which has been applied to visual tracking. We develop a geometric method for visual tracking, in which region covariance is used to model objects appearance; then tracking is led by implementing the particle filter with the constraint that the system state lies in a low dimensional manifold: affine Lie group. The sequential Bayesian updating consists of drawing state samples while moving on the manifold geodesics; the region covariance is updated using a novel approach in a Riemannian space. Our main contribution is developing a general particle filtering-based racking algorithm that explicitly take the geometry of affine Lie groups into consideration in deriving the state equation on Lie groups. Theoretic analysis and experimental evaluations demonstrate the promise and effectiveness of the proposed tracking method.

  11. Particle filter-based track before detect algorithms

    NASA Astrophysics Data System (ADS)

    Boers, Yvo; Driessen, Hans

    2004-01-01

    In this paper we will give a general system setup, that allows the formulation of a wide range of Track Before Detect (TBD) problems. A general basic particle filter algorithm for this system is also provided. TBD is a technique, where tracks are produced directly on the basis of raw (radar) measurements, e.g. power or IQ data, without intermediate processing and decision making. The advantage over classical tracking is that the full information is integrated over time, this leads to a better detection and tracking performance, especially for weak targets. In this paper we look at the filtering and the detection aspect of TBD. We will formulate a detection result, that allows the user to implement any optimal detector in terms of the weights of a running particle filter. We will give a theoretical as well as a numerical (experimental) justification for this. Furthermore, we show that the TBD setup, that is chosen in this paper, allows a straightforward extension to the multi-target case. This easy extension is also due to the fact that the implementation of the solution is by means of a particle filter.

  12. Optimal digital filtering for tremor suppression.

    PubMed

    Gonzalez, J G; Heredia, E A; Rahman, T; Barner, K E; Arce, G R

    2000-05-01

    Remote manually operated tasks such as those found in teleoperation, virtual reality, or joystick-based computer access, require the generation of an intermediate electrical signal which is transmitted to the controlled subsystem (robot arm, virtual environment, or a cursor in a computer screen). When human movements are distorted, for instance, by tremor, performance can be improved by digitally filtering the intermediate signal before it reaches the controlled device. This paper introduces a novel tremor filtering framework in which digital equalizers are optimally designed through pursuit tracking task experiments. Due to inherent properties of the man-machine system, the design of tremor suppression equalizers presents two serious problems: 1) performance criteria leading to optimizations that minimize mean-squared error are not efficient for tremor elimination and 2) movement signals show ill-conditioned autocorrelation matrices, which often result in useless or unstable solutions. To address these problems, a new performance indicator in the context of tremor is introduced, and the optimal equalizer according to this new criterion is developed. Ill-conditioning of the autocorrelation matrix is overcome using a novel method which we call pulled-optimization. Experiments performed with artificially induced vibrations and a subject with Parkinson's disease show significant improvement in performance. Additional results, along with MATLAB source code of the algorithms, and a customizable demo for PC joysticks, are available on the Internet at http:¿tremor-suppression.com. PMID:10851810

  13. GNSS data filtering optimization for ionospheric observation

    NASA Astrophysics Data System (ADS)

    D'Angelo, G.; Spogli, L.; Cesaroni, C.; Sgrigna, V.; Alfonsi, L.; Aquino, M. H. O.

    2015-12-01

    In the last years, the use of GNSS (Global Navigation Satellite Systems) data has been gradually increasing, for both scientific studies and technological applications. High-rate GNSS data, able to generate and output 50-Hz phase and amplitude samples, are commonly used to study electron density irregularities within the ionosphere. Ionospheric irregularities may cause scintillations, which are rapid and random fluctuations of the phase and the amplitude of the received GNSS signals. For scintillation analysis, usually, GNSS signals observed at an elevation angle lower than an arbitrary threshold (usually 15°, 20° or 30°) are filtered out, to remove the possible error sources due to the local environment where the receiver is deployed. Indeed, the signal scattered by the environment surrounding the receiver could mimic ionospheric scintillation, because buildings, trees, etc. might create diffusion, diffraction and reflection. Although widely adopted, the elevation angle threshold has some downsides, as it may under or overestimate the actual impact of multipath due to local environment. Certainly, an incorrect selection of the field of view spanned by the GNSS antenna may lead to the misidentification of scintillation events at low elevation angles. With the aim to tackle the non-ionospheric effects induced by multipath at ground, in this paper we introduce a filtering technique, termed SOLIDIFY (Standalone OutLiers IDentIfication Filtering analYsis technique), aiming at excluding the multipath sources of non-ionospheric origin to improve the quality of the information obtained by the GNSS signal in a given site. SOLIDIFY is a statistical filtering technique based on the signal quality parameters measured by scintillation receivers. The technique is applied and optimized on the data acquired by a scintillation receiver located at the Istituto Nazionale di Geofisica e Vulcanologia, in Rome. The results of the exercise show that, in the considered case of a noisy site under quiet ionospheric conditions, the SOLIDIFY optimization maximizes the quality, instead of the quantity, of the data.

  14. Constrained filter optimization for subsurface landmine detection

    NASA Astrophysics Data System (ADS)

    Torrione, Peter A.; Collins, Leslie; Clodfelter, Fred; Lulich, Dan; Patrikar, Ajay; Howard, Peter; Weaver, Richard; Rosen, Erik

    2006-05-01

    Previous large-scale blind tests of anti-tank landmine detection utilizing the NIITEK ground penetrating radar indicated the potential for very high anti-tank landmine detection probabilities at very low false alarm rates for algorithms based on adaptive background cancellation schemes. Recent data collections under more heterogeneous multi-layered road-scenarios seem to indicate that although adaptive solutions to background cancellation are effective, the adaptive solutions to background cancellation under different road conditions can differ significantly, and misapplication of these adaptive solutions can reduce landmine detection performance in terms of PD/FAR. In this work we present a framework for the constrained optimization of background-estimation filters that specifically seeks to optimize PD/FAR performance as measured by the area under the ROC curve between two FARs. We also consider the application of genetic algorithms to the problem of filter optimization for landmine detection. Results indicate robust results for both static and adaptive background cancellation schemes, and possible real-world advantages and disadvantages of static and adaptive approaches are discussed.

  15. Optimal edge filters explain human blur detection.

    PubMed

    McIlhagga, William H; May, Keith A

    2012-01-01

    Edges are important visual features, providing many cues to the three-dimensional structure of the world. One of these cues is edge blur. Sharp edges tend to be caused by object boundaries, while blurred edges indicate shadows, surface curvature, or defocus due to relative depth. Edge blur also drives accommodation and may be implicated in the correct development of the eye's optical power. Here we use classification image techniques to reveal the mechanisms underlying blur detection in human vision. Observers were shown a sharp and a blurred edge in white noise and had to identify the blurred edge. The resultant smoothed classification image derived from these experiments was similar to a derivative of a Gaussian filter. We also fitted a number of edge detection models (MIRAGE, N(1), and N(3)(+)) and the ideal observer to observer responses, but none performed as well as the classification image. However, observer responses were well fitted by a recently developed optimal edge detector model, coupled with a Bayesian prior on the expected blurs in the stimulus. This model outperformed the classification image when performance was measured by the Akaike Information Criterion. This result strongly suggests that humans use optimal edge detection filters to detect edges and encode their blur. PMID:22984222

  16. Program Computes SLM Inputs To Implement Optimal Filters

    NASA Technical Reports Server (NTRS)

    Barton, R. Shane; Juday, Richard D.; Alvarez, Jennifer L.

    1995-01-01

    Minimum Euclidean Distance Optimal Filter (MEDOF) program generates filters for use in optical correlators. Analytically optimizes filters on arbitrary spatial light modulators (SLMs) of such types as coupled, binary, fully complex, and fractional-2pi-phase. Written in C language.

  17. Groupwise surface correspondence using particle filtering

    NASA Astrophysics Data System (ADS)

    Li, Guangxu; Kim, Hyoungseop; Tan, Joo Kooi; Ishikawa, Seiji

    2015-03-01

    To obtain an effective interpretation of organic shape using statistical shape models (SSMs), the correspondence of the landmarks through all the training samples is the most challenging part in model building. In this study, a coarse-tofine groupwise correspondence method for 3-D polygonal surfaces is proposed. We manipulate a reference model in advance. Then all the training samples are mapped to a unified spherical parameter space. According to the positions of landmarks of the reference model, the candidate regions for correspondence are chosen. Finally we refine the perceptually correct correspondences between landmarks using particle filter algorithm, where the likelihood of local surface features are introduced as the criterion. The proposed method was performed on the correspondence of 9 cases of left lung training samples. Experimental results show the proposed method is flexible and under-constrained.

  18. Implementation and performance of FPGA-accelerated particle flow filter

    NASA Astrophysics Data System (ADS)

    Charalampidis, Dimitrios; Jilkov, Vesselin P.; Wu, Jiande

    2015-09-01

    The particle flow filters, proposed by Daum & Hwang, provide a powerful means for density-based nonlinear filtering but their computation is intense and may be prohibitive for real-time applications. This paper proposes a design for superfast implementation of the exact particle flow filter using a field-programmable gate array (FPGA) as a parallel environment to speedup computation. Simulation results from a nonlinear filtering example are presented to demonstrate that using FPGA can dramatically accelerate particle flow filters through parallelization at the expense of a tolerable loss in accuracy as compared to nonparallel implementation.

  19. Simulations of acoustic tomography using a particle filter

    NASA Astrophysics Data System (ADS)

    Zhang, Ming; Xu, Wen; Li, Jianlong

    2012-11-01

    This paper uses the state-space model to track the sound speed profile between a moving source suspended from a ship and a fixed vertical linear array. The particle filtering approach is presented to handle this nonlinear and non-Gaussian inverse problem. Simulation results show that the particle filter with a high particle number outperforms the extended Kalman filter; however, the performance degrades when the dimension of the state increases.

  20. Comparative evaluation of ensemble Kalman filter, particle filter and variational techniques for river discharge forecast

    NASA Astrophysics Data System (ADS)

    Hirpa, F. A.; Gebremichael, M.; LEE, H.; Hopson, T. M.

    2012-12-01

    Hydrologic data assimilation techniques provide a means to improve river discharge forecasts through updating hydrologic model states and correcting the atmospheric forcing data via optimally combining model outputs with observations. The performance of the assimilation procedure, however, depends on the data assimilation techniques used and the amount of uncertainty in the data sets. To investigate the effects of these, we comparatively evaluate three data assimilation techniques, including ensemble Kalman filter (EnKF), particle filter (PF) and variational (VAR) technique, which assimilate discharge and synthetic soil moisture data at various uncertainty levels into the Sacramento Soil Moisture accounting (SAC-SMA) model used by the National Weather Service (NWS) for river forecasting in The United States. The study basin is Greens Bayou watershed with area of 178 km2 in eastern Texas. In the presentation, we summarize the results of the comparisons, and discuss the challenges of applying each technique for hydrologic applications.

  1. Metal finishing wastewater pressure filter optimization

    SciTech Connect

    Norford, S.W.; Diener, G.A.; Martin, H.L.

    1992-12-31

    The 300-M Area Liquid Effluent Treatment Facility (LETF) of the Savannah River Site (SRS) is an end-of-pipe industrial wastewater treatment facility, that uses precipitation and filtration which is the EPA Best Available Technology economically achievable for a Metal Finishing and Aluminum Form Industries. The LETF consists of three close-coupled treatment facilities: the Dilute Effluent Treatment Facility (DETF), which uses wastewater equalization, physical/chemical precipitation, flocculation, and filtration; the Chemical Treatment Facility (CTF), which slurries the filter cake generated from the DETF and pumps it to interim-StatuS RCRA storage tanks; and the Interim Treatment/Storage Facility (IT/SF) which stores the waste from the CTF until the waste is stabilized/solidified for permanent disposal, 85% of the stored waste is from past nickel plating and aluminum canning of depleted uranium targets for the SRS nuclear reactors. Waste minimization and filtration efficiency are key to cost effective treatment of the supernate, because the waste filter cake generated is returned to the IT/SF. The DETF has been successfully optimized to achieve maximum efficiency and to minimize waste generation.

  2. Metal finishing wastewater pressure filter optimization

    SciTech Connect

    Norford, S.W.; Diener, G.A.; Martin, H.L.

    1992-01-01

    The 300-M Area Liquid Effluent Treatment Facility (LETF) of the Savannah River Site (SRS) is an end-of-pipe industrial wastewater treatment facility, that uses precipitation and filtration which is the EPA Best Available Technology economically achievable for a Metal Finishing and Aluminum Form Industries. The LETF consists of three close-coupled treatment facilities: the Dilute Effluent Treatment Facility (DETF), which uses wastewater equalization, physical/chemical precipitation, flocculation, and filtration; the Chemical Treatment Facility (CTF), which slurries the filter cake generated from the DETF and pumps it to interim-StatuS RCRA storage tanks; and the Interim Treatment/Storage Facility (IT/SF) which stores the waste from the CTF until the waste is stabilized/solidified for permanent disposal, 85% of the stored waste is from past nickel plating and aluminum canning of depleted uranium targets for the SRS nuclear reactors. Waste minimization and filtration efficiency are key to cost effective treatment of the supernate, because the waste filter cake generated is returned to the IT/SF. The DETF has been successfully optimized to achieve maximum efficiency and to minimize waste generation.

  3. A multiple feature based particle filter using mutual information maximization

    NASA Astrophysics Data System (ADS)

    Hong, Kihyun; Han, Kyuseo

    2011-01-01

    In designing a tracking algorithm, utilizing several different features, e.g., color histogram, gradient histogram and other object descriptors, is preferable to increase robustness of tracking performance. In this paper, we propose a multiple feature fusion framework to improve the tracking by assigning appropriate weights to individual features. The feature weights are optimally obtained by a waterfilling procedure that maximizes mutual information between target object features and query features. Especially, in this paper, we focus on a particle filter tracking implementation of the multiple feature fusion framework. Our experiments show that object tracking with multiple features outperforms single feature based tracking methods and illustrates that the proposed optimal feature weighting increases robustness of multiple-feature based tracking performance.

  4. Human-Manipulator Interface Using Particle Filter

    PubMed Central

    Wang, Xueqian

    2014-01-01

    This paper utilizes a human-robot interface system which incorporates particle filter (PF) and adaptive multispace transformation (AMT) to track the pose of the human hand for controlling the robot manipulator. This system employs a 3D camera (Kinect) to determine the orientation and the translation of the human hand. We use Camshift algorithm to track the hand. PF is used to estimate the translation of the human hand. Although a PF is used for estimating the translation, the translation error increases in a short period of time when the sensors fail to detect the hand motion. Therefore, a methodology to correct the translation error is required. What is more, to be subject to the perceptive limitations and the motor limitations, human operator is hard to carry out the high precision operation. This paper proposes an adaptive multispace transformation (AMT) method to assist the operator to improve the accuracy and reliability in determining the pose of the robot. The human-robot interface system was experimentally tested in a lab environment, and the results indicate that such a system can successfully control a robot manipulator. PMID:24757430

  5. Tractable particle filters for robot fault diagnosis

    NASA Astrophysics Data System (ADS)

    Verma, Vandi

    Experience has shown that even carefully designed and tested robots may encounter anomalous situations. It is therefore important for robots to monitor their state so that anomalous situations may be detected in a timely manner. Robot fault diagnosis typically requires tracking a very large number of possible faults in complex non-linear dynamic systems with noisy sensors. Traditional methods either ignore the uncertainly or use linear approximations of nonlinear system dynamics. Such approximations are often unrealistic, and as a result faults either go undetected or become confused with non-fault conditions. Probability theory provides a natural representation for uncertainty, but an exact Bayesian solution for the diagnosis problem is intractable. Classical Monte Carlo methods, such as particle filters, suffer from substantial computational complexity. This is particularly true with the presence of rare, yet important events, such as many system faults. The thesis presents a set of complementary algorithms that provide an approach for computationally tractable fault diagnosis. These algorithms leverage probabilistic approaches to decision theory and information theory to efficiently track a large number of faults in a general dynamic system with noisy measurements. The problem of fault diagnosis is represented as hybrid (discrete/continuous) state estimation. Taking advantage of structure in the domain it dynamically concentrates computation in the regions of state space that are currently most relevant without losing track of less likely states. Experiments with a dynamic simulation of a six-wheel rocker-bogie rover show a significant improvement in performance over the classical approach.

  6. Application of particle filtering algorithm in image reconstruction of EMT

    NASA Astrophysics Data System (ADS)

    Wang, Jingwen; Wang, Xu

    2015-07-01

    To improve the image quality of electromagnetic tomography (EMT), a new image reconstruction method of EMT based on a particle filtering algorithm is presented. Firstly, the principle of image reconstruction of EMT is analyzed. Then the search process for the optimal solution for image reconstruction of EMT is described as a system state estimation process, and the state space model is established. Secondly, to obtain the minimum variance estimation of image reconstruction, the optimal weights of random samples obtained from the state space are calculated from the measured information. Finally, simulation experiments with five different flow regimes are performed. The experimental results have shown that the average image error of reconstruction results obtained by the method mentioned in this paper is 42.61%, and the average correlation coefficient with the original image is 0.8706, which are much better than corresponding indicators obtained by LBP, Landweber and Kalman Filter algorithms. So, this EMT image reconstruction method has high efficiency and accuracy, and provides a new method and means for EMT research.

  7. A hybrid method for optimization of the adaptive Goldstein filter

    NASA Astrophysics Data System (ADS)

    Jiang, Mi; Ding, Xiaoli; Tian, Xin; Malhotra, Rakesh; Kong, Weixue

    2014-12-01

    The Goldstein filter is a well-known filter for interferometric filtering in the frequency domain. The main parameter of this filter, alpha, is set as a power of the filtering function. Depending on it, considered areas are strongly or weakly filtered. Several variants have been developed to adaptively determine alpha using different indicators such as the coherence, and phase standard deviation. The common objective of these methods is to prevent areas with low noise from being over filtered while simultaneously allowing stronger filtering over areas with high noise. However, the estimators of these indicators are biased in the real world and the optimal model to accurately determine the functional relationship between the indicators and alpha is also not clear. As a result, the filter always under- or over-filters and is rarely correct. The study presented in this paper aims to achieve accurate alpha estimation by correcting the biased estimator using homogeneous pixel selection and bootstrapping algorithms, and by developing an optimal nonlinear model to determine alpha. In addition, an iteration is also merged into the filtering procedure to suppress the high noise over incoherent areas. The experimental results from synthetic and real data show that the new filter works well under a variety of conditions and offers better and more reliable performance when compared to existing approaches.

  8. Optimal design of AC filter circuits in HVDC converter stations

    SciTech Connect

    Saied, M.M.; Khader, S.A.

    1995-12-31

    This paper investigates the reactive power as well as the harmonic conditions on both the valve and the AC-network sides of a HVDC converter station. The effect of the AC filter circuits is accurately modeled. The program is then augmented by adding an optimization routine. It can identify the optimal filter configuration, yielding the minimum current distortion factor at the AC network terminals for a prespecified fundamental reactive power to be provided by the filter. Several parameter studies were also conducted to illustrate the effect of accidental or intentional deletion of one of the filter branches.

  9. Optimal filter bandwidth for pulse oximetry

    NASA Astrophysics Data System (ADS)

    Stuban, Norbert; Niwayama, Masatsugu

    2012-10-01

    Pulse oximeters contain one or more signal filtering stages between the photodiode and microcontroller. These filters are responsible for removing the noise while retaining the useful frequency components of the signal, thus improving the signal-to-noise ratio. The corner frequencies of these filters affect not only the noise level, but also the shape of the pulse signal. Narrow filter bandwidth effectively suppresses the noise; however, at the same time, it distorts the useful signal components by decreasing the harmonic content. In this paper, we investigated the influence of the filter bandwidth on the accuracy of pulse oximeters. We used a pulse oximeter tester device to produce stable, repetitive pulse waves with digitally adjustable R ratio and heart rate. We built a pulse oximeter and attached it to the tester device. The pulse oximeter digitized the current of its photodiode directly, without any analog signal conditioning. We varied the corner frequency of the low-pass filter in the pulse oximeter in the range of 0.66-15 Hz by software. For the tester device, the R ratio was set to R = 1.00, and the R ratio deviation measured by the pulse oximeter was monitored as a function of the corner frequency of the low-pass filter. The results revealed that lowering the corner frequency of the low-pass filter did not decrease the accuracy of the oxygen level measurements. The lowest possible value of the corner frequency of the low-pass filter is the fundamental frequency of the pulse signal. We concluded that the harmonics of the pulse signal do not contribute to the accuracy of pulse oximetry. The results achieved by the pulse oximeter tester were verified by human experiments, performed on five healthy subjects. The results of the human measurements confirmed that filtering out the harmonics of the pulse signal does not degrade the accuracy of pulse oximetry.

  10. Optimal Filter Systems for Photometric Redshift Estimation

    NASA Astrophysics Data System (ADS)

    Benítez, N.; Moles, M.; Aguerri, J. A. L.; Alfaro, E.; Broadhurst, T.; Cabrera-Caño, J.; Castander, F. J.; Cepa, J.; Cerviño, M.; Cristóbal-Hornillos, D.; Fernández-Soto, A.; González Delgado, R. M.; Infante, L.; Márquez, I.; Martínez, V. J.; Masegosa, J.; Del Olmo, A.; Perea, J.; Prada, F.; Quintana, J. M.; Sánchez, S. F.

    2009-02-01

    In the coming years, several cosmological surveys will rely on imaging data to estimate the redshift of galaxies, using traditional filter systems with 4-5 optical broad bands; narrower filters improve the spectral resolution, but strongly reduce the total system throughput. We explore how photometric redshift performance depends on the number of filters nf , characterizing the survey depth by the fraction of galaxies with unambiguous redshift estimates. For a combination of total exposure time and telescope imaging area of 270 hr m2, 4-5 filter systems perform significantly worse, both in completeness depth and precision, than systems with nf gsim 8 filters. Our results suggest that for low nf the color-redshift degeneracies overwhelm the improvements in photometric depth, and that even at higher nf the effective photometric redshift depth decreases much more slowly with filter width than naively expected from the reduction in the signal-to-noise ratio. Adding near-IR observations improves the performance of low-nf systems, but still the system which maximizes the photometric redshift completeness is formed by nine filters with logarithmically increasing bandwidth (constant resolution) and half-band overlap, reaching ~0.7 mag deeper, with 10% better redshift precision, than 4-5 filter systems. A system with 20 constant-width, nonoverlapping filters reaches only ~0.1 mag shallower than 4-5 filter systems, but has a precision almost three times better, δz = 0.014(1 + z) versus δz = 0.042(1 + z). We briefly discuss a practical implementation of such a photometric system: the ALHAMBRA Survey.

  11. Symmetric Phase-Only Filtering in Particle-Image Velocimetry

    NASA Technical Reports Server (NTRS)

    Wemet, Mark P.

    2008-01-01

    Symmetrical phase-only filtering (SPOF) can be exploited to obtain substantial improvements in the results of data processing in particle-image velocimetry (PIV). In comparison with traditional PIV data processing, SPOF PIV data processing yields narrower and larger amplitude correlation peaks, thereby providing more-accurate velocity estimates. The higher signal-to-noise ratios associated with the higher amplitude correlation peaks afford greater robustness and reliability of processing. SPOF also affords superior performance in the presence of surface flare light and/or background light. SPOF algorithms can readily be incorporated into pre-existing algorithms used to process digitized image data in PIV, without significantly increasing processing times. A summary of PIV and traditional PIV data processing is prerequisite to a meaningful description of SPOF PIV processing. In PIV, a pulsed laser is used to illuminate a substantially planar region of a flowing fluid in which particles are entrained. An electronic camera records digital images of the particles at two instants of time. The components of velocity of the fluid in the illuminated plane can be obtained by determining the displacements of particles between the two illumination pulses. The objective in PIV data processing is to compute the particle displacements from the digital image data. In traditional PIV data processing, to which the present innovation applies, the two images are divided into a grid of subregions and the displacements determined from cross-correlations between the corresponding sub-regions in the first and second images. The cross-correlation process begins with the calculation of the Fourier transforms (or fast Fourier transforms) of the subregion portions of the images. The Fourier transforms from the corresponding subregions are multiplied, and this product is inverse Fourier transformed, yielding the cross-correlation intensity distribution. The average displacement of the particles across a subregion results in a displacement of the correlation peak from the center of the correlation plane. The velocity is then computed from the displacement of the correlation peak and the time between the recording of the two images. The process as described thus far is performed for all the subregions. The resulting set of velocities in grid cells amounts to a velocity vector map of the flow field recorded on the image plane. In traditional PIV processing, surface flare light and bright background light give rise to a large, broad correlation peak, at the center of the correlation plane, that can overwhelm the true particle- displacement correlation peak. This has made it necessary to resort to tedious image-masking and background-subtraction procedures to recover the relatively small amplitude particle-displacement correlation peak. SPOF is a variant of phase-only filtering (POF), which, in turn, is a variant of matched spatial filtering (MSF). In MSF, one projects a first image (denoted the input image) onto a second image (denoted the filter) as part of a computation to determine how much and what part of the filter is present in the input image. MSF is equivalent to cross-correlation. In POF, the frequency-domain content of the MSF filter is modified to produce a unitamplitude (phase-only) object. POF is implemented by normalizing the Fourier transform of the filter by its magnitude. The advantage of POFs is that they yield correlation peaks that are sharper and have higher signal-to-noise ratios than those obtained through traditional MSF. In the SPOF, these benefits of POF can be extended to PIV data processing. The SPOF yields even better performance than the POF approach, which is uniquely applicable to PIV type image data. In SPOF as now applied to PIV data processing, a subregion of the first image is treated as the input image and the corresponding subregion of the second image is treated as the filter. The Fourier transforms from both the firs and second- image subregions are normalized by the square roots of their respective magnitudes. This scheme yields optimal performance because the amounts of normalization applied to the spatial-frequency contents of the input and filter scenes are just enough to enhance their high-spatial-frequency contents while reducing their spurious low-spatial-frequency content. As a result, in SPOF PIV processing, particle-displacement correlation peaks can readily be detected above spurious background peaks, without need for masking or background subtraction.

  12. Simultaneous Eye Tracking and Blink Detection with Interactive Particle Filters

    NASA Astrophysics Data System (ADS)

    Wu, Junwen; Trivedi, Mohan M.

    2007-12-01

    We present a system that simultaneously tracks eyes and detects eye blinks. Two interactive particle filters are used for this purpose, one for the closed eyes and the other one for the open eyes. Each particle filter is used to track the eye locations as well as the scales of the eye subjects. The set of particles that gives higher confidence is defined as the primary set and the other one is defined as the secondary set. The eye location is estimated by the primary particle filter, and whether the eye status is open or closed is also decided by the label of the primary particle filter. When a new frame comes, the secondary particle filter is reinitialized according to the estimates from the primary particle filter. We use autoregression models for describing the state transition and a classification-based model for measuring the observation. Tensor subspace analysis is used for feature extraction which is followed by a logistic regression model to give the posterior estimation. The performance is carefully evaluated from two aspects: the blink detection rate and the tracking accuracy. The blink detection rate is evaluated using videos from varying scenarios, and the tracking accuracy is given by comparing with the benchmark data obtained using the Vicon motion capturing system. The setup for obtaining benchmark data for tracking accuracy evaluation is presented and experimental results are shown. Extensive experimental evaluations validate the capability of the algorithm.

  13. Optimal Gain Filter Design for Perceptual Acoustic Echo Suppressor

    NASA Astrophysics Data System (ADS)

    Kim, Kihyeon; Ko, Hanseok

    This Letter proposes an optimal gain filter for the perceptual acoustic echo suppressor. We designed an optimally-modified log-spectral amplitude estimation algorithm for the gain filter in order to achieve robust suppression of echo and noise. A new parameter including information about interferences (echo and noise) of single-talk duration is statistically analyzed, and then the speech absence probability and the a posteriori SNR are judiciously estimated to determine the optimal solution. The experiments show that the proposed gain filter attains a significantly improved reduction of echo and noise with less speech distortion.

  14. Ballistic target tracking algorithm based on improved particle filtering

    NASA Astrophysics Data System (ADS)

    Ning, Xiao-lei; Chen, Zhan-qi; Li, Xiao-yang

    2015-10-01

    Tracking ballistic re-entry target is a typical nonlinear filtering problem. In order to track the ballistic re-entry target in the nonlinear and non-Gaussian complex environment, a novel chaos map particle filter (CMPF) is used to estimate the target state. CMPF has better performance in application to estimate the state and parameter of nonlinear and non-Gassuian system. The Monte Carlo simulation results show that, this method can effectively solve particle degeneracy and particle impoverishment problem by improving the efficiency of particle sampling to obtain the better particles to part in estimation. Meanwhile CMPF can improve the state estimation precision and convergence velocity compared with EKF, UKF and the ordinary particle filter.

  15. Entropy-based optimization of wavelet spatial filters.

    PubMed

    Farina, Darino; Kamavuako, Ernest Nlandu; Wu, Jian; Naddeo, Francesco

    2008-03-01

    A new class of spatial filters for surface electromyographic (EMG) signal detection is proposed. These filters are based on the 2-D spatial wavelet decomposition of the surface EMG recorded with a grid of electrodes and inverse transformation after zeroing a subset of the transformation coefficients. The filter transfer function depends on the selected mother wavelet in the two spatial directions. Wavelet parameterization is proposed with the aim of signal-based optimization of the transfer function of the spatial filter. The optimization criterion was the minimization of the entropy of the time samples of the output signal. The optimized spatial filter is linear and space invariant. In simulated and experimental recordings, the optimized wavelet filter showed increased selectivity with respect to previously proposed filters. For example, in simulation, the ratio between the peak-to-peak amplitude of action potentials generated by motor units 20 degrees apart in the transversal direction was 8.58% (with monopolar recording), 2.47% (double differential), 2.59% (normal double differential), and 0.47% (optimized wavelet filter). In experimental recordings, the duration of the detected action potentials decreased from (mean +/- SD) 6.9 +/- 0.3 ms (monopolar recording), to 4.5 +/- 0.2 ms (normal double differential), 3.7 +/- 0.2 (double differential), and 3.0 +/- 0.1 ms (optimized wavelet filter). In conclusion, the new class of spatial filters with the proposed signal-based optimization of the transfer function allows better discrimination of individual motor unit activities in surface EMG recordings than it was previously possible. PMID:18334382

  16. Method of concurrently filtering particles and collecting gases

    SciTech Connect

    Mitchell, Mark A; Meike, Annemarie; Anderson, Brian L

    2015-04-28

    A system for concurrently filtering particles and collecting gases. Materials are be added (e.g., via coating the ceramic substrate, use of loose powder(s), or other means) to a HEPA filter (ceramic, metal, or otherwise) to collect gases (e.g., radioactive gases such as iodine). The gases could be radioactive, hazardous, or valuable gases.

  17. Applying sequential Monte Carlo methods into a distributed hydrologic model: lagged particle filtering approach with regularization

    NASA Astrophysics Data System (ADS)

    Noh, S. J.; Tachikawa, Y.; Shiiba, M.; Kim, S.

    2011-10-01

    Data assimilation techniques have received growing attention due to their capability to improve prediction. Among various data assimilation techniques, sequential Monte Carlo (SMC) methods, known as "particle filters", are a Bayesian learning process that has the capability to handle non-linear and non-Gaussian state-space models. In this paper, we propose an improved particle filtering approach to consider different response times of internal state variables in a hydrologic model. The proposed method adopts a lagged filtering approach to aggregate model response until the uncertainty of each hydrologic process is propagated. The regularization with an additional move step based on the Markov chain Monte Carlo (MCMC) methods is also implemented to preserve sample diversity under the lagged filtering approach. A distributed hydrologic model, water and energy transfer processes (WEP), is implemented for the sequential data assimilation through the updating of state variables. The lagged regularized particle filter (LRPF) and the sequential importance resampling (SIR) particle filter are implemented for hindcasting of streamflow at the Katsura catchment, Japan. Control state variables for filtering are soil moisture content and overland flow. Streamflow measurements are used for data assimilation. LRPF shows consistent forecasts regardless of the process noise assumption, while SIR has different values of optimal process noise and shows sensitive variation of confidential intervals, depending on the process noise. Improvement of LRPF forecasts compared to SIR is particularly found for rapidly varied high flows due to preservation of sample diversity from the kernel, even if particle impoverishment takes place.

  18. Multifeature fusion tracking in a particle filter framework

    NASA Astrophysics Data System (ADS)

    Pei, Lizhi; Zhang, Peng; Wang, Runsheng

    2009-10-01

    Particle filtering has been proven very successful for non-gaussian and non-linear estimation problems. In this study we used the particle filtering technique with multiple features to track the moving object effectively in video image. The object tracking system relies on the deterministic search of window, whose color content matches a reference histogram model. A simple histogram-based color model is used to develop our observation system. Secondly and finally, we describe a new approach for moving object tracking with particle filter by PCA transform technique. Our observation system of particle filter uses the combination of color and PCA features with a likelihood measurement. Experiment results show that the algorithm can effectively handle the effect of illumination, and is stable and robust.

  19. Particle filter-based prognostics: Review, discussion and perspectives

    NASA Astrophysics Data System (ADS)

    Jouin, Marine; Gouriveau, Rafael; Hissel, Daniel; Péra, Marie-Cécile; Zerhouni, Noureddine

    2016-05-01

    Particle filters are of great concern in a large variety of engineering fields such as robotics, statistics or automatics. Recently, it has developed among Prognostics and Health Management (PHM) applications for diagnostics and prognostics. According to some authors, it has ever become a state-of-the-art technique for prognostics. Nowadays, around 50 papers dealing with prognostics based on particle filters can be found in the literature. However, no comprehensive review has been proposed on the subject until now. This paper aims at analyzing the way particle filters are used in that context. The development of the tool in the prognostics' field is discussed before entering the details of its practical use and implementation. Current issues are identified, analyzed and some solutions or work trails are proposed. All this aims at highlighting future perspectives as well as helping new users to start with particle filters in the goal of prognostics.

  20. Contrasting Particle Clogging in Soils and Granular Media Filters

    NASA Astrophysics Data System (ADS)

    Mays, D. C.

    2005-12-01

    Deposition of colloidal particles leads to permeability reduction (or clogging) in the soil geomembrane, which reduces fluxes, alters flow patterns, and limits both colloid-associated contaminant transport and delivery of colloidal reactants for purposes of remediation. Comparison of experimental results for soils and granular media filters reveals qualitatively different clogging phenomena with regard to (1) particle stabilization, (2) fluid velocity, and (3) the fractal dimension of particle deposits. These differences have important implications for contaminant hydrology, because the classical approach for understanding particles in natural environments is taken from the filtration literature, which is based on clean granular media. Accordingly, many of the relevant experiments have been performed with granular filters using media such as glass beads or quartz sand. In such filters, clogging is associated with destabilized particles, slower fluid velocity and deposits with smaller fractal dimensions. In contrast, in soils clogging is associated with stabilized particles, faster fluid velocity and deposits with larger fractal dimensions. With regard to these variables, soils are opposite to filters but identical to cake filtration. Numerous examples will be presented from the filtration literature and the soil science literature to illustrate these differing viewpoints. This analysis demonstrates that experiments on clean granular media filters should not be expected to predict particle clogging in soils, sandstones or other natural porous materials containing more than a few percent fines.

  1. Geomagnetic modeling by optimal recursive filtering

    NASA Technical Reports Server (NTRS)

    Gibbs, B. P.; Estes, R. H.

    1981-01-01

    The results of a preliminary study to determine the feasibility of using Kalman filter techniques for geomagnetic field modeling are given. Specifically, five separate field models were computed using observatory annual means, satellite, survey and airborne data for the years 1950 to 1976. Each of the individual field models used approximately five years of data. These five models were combined using a recursive information filter (a Kalman filter written in terms of information matrices rather than covariance matrices.) The resulting estimate of the geomagnetic field and its secular variation was propogated four years past the data to the time of the MAGSAT data. The accuracy with which this field model matched the MAGSAT data was evaluated by comparisons with predictions from other pre-MAGSAT field models. The field estimate obtained by recursive estimation was found to be superior to all other models.

  2. PSO Algorithm Particle Filters for Improving the Performance of Lane Detection and Tracking Systems in Difficult Roads

    PubMed Central

    Cheng, Wen-Chang

    2012-01-01

    In this paper we propose a robust lane detection and tracking method by combining particle filters with the particle swarm optimization method. This method mainly uses the particle filters to detect and track the local optimum of the lane model in the input image and then seeks the global optimal solution of the lane model by a particle swarm optimization method. The particle filter can effectively complete lane detection and tracking in complicated or variable lane environments. However, the result obtained is usually a local optimal system status rather than the global optimal system status. Thus, the particle swarm optimization method is used to further refine the global optimal system status in all system statuses. Since the particle swarm optimization method is a global optimization algorithm based on iterative computing, it can find the global optimal lane model by simulating the food finding way of fish school or insects under the mutual cooperation of all particles. In verification testing, the test environments included highways and ordinary roads as well as straight and curved lanes, uphill and downhill lanes, lane changes, etc. Our proposed method can complete the lane detection and tracking more accurately and effectively then existing options. PMID:23235453

  3. Forward-looking infrared 3D target tracking via combination of particle filter and SIFT

    NASA Astrophysics Data System (ADS)

    Li, Xing; Cao, Zhiguo; Yan, Ruicheng; Li, Tuo

    2013-10-01

    Aiming at the problem of tracking 3D target in forward-looking infrared (FLIR) image, this paper proposes a high-accuracy robust tracking algorithm based on SIFT and particle filter. The main contribution of this paper is the proposal of a new method of estimating the affine transformation matrix parameters based on Monte Carlo methods of particle filter. At first, we extract SIFT features on infrared image, and calculate the initial affine transformation matrix with optimal candidate key points. Then we take affine transformation parameters as particles, and use SIR (Sequential Importance Resampling) particle filter to estimate the best position, thus implementing our algorithm. The experiments demonstrate that our algorithm proves to be robust with high accuracy.

  4. Optimal Sharpening of Compensated Comb Decimation Filters: Analysis and Design

    PubMed Central

    Troncoso Romero, David Ernesto

    2014-01-01

    Comb filters are a class of low-complexity filters especially useful for multistage decimation processes. However, the magnitude response of comb filters presents a droop in the passband region and low stopband attenuation, which is undesirable in many applications. In this work, it is shown that, for stringent magnitude specifications, sharpening compensated comb filters requires a lower-degree sharpening polynomial compared to sharpening comb filters without compensation, resulting in a solution with lower computational complexity. Using a simple three-addition compensator and an optimization-based derivation of sharpening polynomials, we introduce an effective low-complexity filtering scheme. Design examples are presented in order to show the performance improvement in terms of passband distortion and selectivity compared to other methods based on the traditional Kaiser-Hamming sharpening and the Chebyshev sharpening techniques recently introduced in the literature. PMID:24578674

  5. Particle-filter-based phase estimation in digital holographic interferometry.

    PubMed

    Waghmare, Rahul G; Ram Sukumar, P; Subrahmanyam, G R K S; Singh, Rakesh Kumar; Mishra, Deepak

    2016-03-01

    In this paper, we propose a particle-filter-based technique for the analysis of a reconstructed interference field. The particle filter and its variants are well proven as tracking filters in non-Gaussian and nonlinear situations. We propose to apply the particle filter for direct estimation of phase and its derivatives from digital holographic interferometric fringes via a signal-tracking approach on a Taylor series expanded state model and a polar-to-Cartesian-conversion-based measurement model. Computation of sample weights through non-Gaussian likelihood forms the major contribution of the proposed particle-filter-based approach compared to the existing unscented-Kalman-filter-based approach. It is observed that the proposed approach is highly robust to noise and outperforms the state-of-the-art especially at very low signal-to-noise ratios (i.e., especially in the range of -5 to 20 dB). The proposed approach, to the best of our knowledge, is the only method available for phase estimation from severely noisy fringe patterns even when the underlying phase pattern is rapidly varying and has a larger dynamic range. Simulation results and experimental data demonstrate the fact that the proposed approach is a better choice for direct phase estimation. PMID:26974901

  6. Analysis of Video-Based Microscopic Particle Trajectories Using Kalman Filtering

    PubMed Central

    Wu, Pei-Hsun; Agarwal, Ashutosh; Hess, Henry; Khargonekar, Pramod P.; Tseng, Yiider

    2010-01-01

    Abstract The fidelity of the trajectories obtained from video-based particle tracking determines the success of a variety of biophysical techniques, including in situ single cell particle tracking and in vitro motility assays. However, the image acquisition process is complicated by system noise, which causes positioning error in the trajectories derived from image analysis. Here, we explore the possibility of reducing the positioning error by the application of a Kalman filter, a powerful algorithm to estimate the state of a linear dynamic system from noisy measurements. We show that the optimal Kalman filter parameters can be determined in an appropriate experimental setting, and that the Kalman filter can markedly reduce the positioning error while retaining the intrinsic fluctuations of the dynamic process. We believe the Kalman filter can potentially serve as a powerful tool to infer a trajectory of ultra-high fidelity from noisy images, revealing the details of dynamic cellular processes. PMID:20550894

  7. COMPUTATIONS ON THE PERFORMANCE OF PARTICLE FILTERS AND ELECTRONIC AIR CLEANERS

    EPA Science Inventory

    The paper discusses computations on the performance of particle filters and electronic air cleaners (EACs). he collection efficiency of particle filters and ACs is calculable if certain factors can be assumed or calibrated. or fibrous particulate filters, measurement of collectio...

  8. COMPUTATIONS ON THE PERFORMANCE OF PARTICLE FILTERS AND ELECTRONIC AIR CLEANERS

    EPA Science Inventory

    The paper discusses computations on the performance of particle filters and electronic air cleaners (EACs). The collection efficiency of particle filters and ACs is calculable if certain factors can be assumed or calibrated. For fibrous particulate filters, measurement of colle...

  9. Optimization of OT-MACH Filter Generation for Target Recognition

    NASA Technical Reports Server (NTRS)

    Johnson, Oliver C.; Edens, Weston; Lu, Thomas T.; Chao, Tien-Hsin

    2009-01-01

    An automatic Optimum Trade-off Maximum Average Correlation Height (OT-MACH) filter generator for use in a gray-scale optical correlator (GOC) has been developed for improved target detection at JPL. While the OT-MACH filter has been shown to be an optimal filter for target detection, actually solving for the optimum is too computationally intensive for multiple targets. Instead, an adaptive step gradient descent method was tested to iteratively optimize the three OT-MACH parameters, alpha, beta, and gamma. The feedback for the gradient descent method was a composite of the performance measures, correlation peak height and peak to side lobe ratio. The automated method generated and tested multiple filters in order to approach the optimal filter quicker and more reliably than the current manual method. Initial usage and testing has shown preliminary success at finding an approximation of the optimal filter, in terms of alpha, beta, gamma values. This corresponded to a substantial improvement in detection performance where the true positive rate increased for the same average false positives per image.

  10. Effect of particle-fiber friction coefficient on ultrafine aerosol particles clogging in nanofiber based filter

    NASA Astrophysics Data System (ADS)

    Sambaer, Wannes; Zatloukal, Martin; Kimmer, Dusan

    2013-04-01

    Realistic SEM image based 3D filter model considering transition/free molecular flow regime, Brownian diffusion, aerodynamic slip, particle-fiber and particle-particle interactions together with a novel Euclidian distance map based methodology for the pressure drop calculation has been utilized for a polyurethane nanofiber based filter prepared via electrospinning process in order to more deeply understand the effect of particle-fiber friction coefficient on filter clogging and basic filter characteristics. Based on the performed theoretical analysis, it has been revealed that the increase in the fiber-particle friction coefficient causes, firstly, more weaker particle penetration in the filter, creation of dense top layers and generation of higher pressure drop (surface filtration) in comparison with lower particle-fiber friction coefficient filter for which deeper particle penetration takes place (depth filtration), secondly, higher filtration efficiency, thirdly, higher quality factor and finally, higher quality factor sensitivity to the increased collected particle mass. Moreover, it has been revealed that even if the particle-fiber friction coefficient is different, the cake morphology is very similar.

  11. Robust tracking algorithm using mean-shift and particle filter

    NASA Astrophysics Data System (ADS)

    Wang, Jianhua; Liang, Wei

    2011-12-01

    Aiming to the problems that Mean-Shift algorithm costs low computation, but easy to fall into local maximum, and huge computation of Particle Filter tracking algorithm leads to low real-time processing capacity, according to the need of real stereo vision measurement system, a kind of tracking algorithm which combines Mean-Shift and Particle Filter by essentiality function is proposed. Under the condition without occlusion, Mean-Shift is used to track object. When object is occluded, Particle Filter is applied to accomplish the later object tracking. These two algorithms alternate by a defined threshold. The tracking algorithm is used into real stereo vision measurement system. Experiment result indicates that the algorithm takes on high efficiency, so it is of high practicability.

  12. Fish tracking by combining motion based segmentation and particle filtering

    NASA Astrophysics Data System (ADS)

    Bichot, E.; Mascarilla, L.; Courtellemont, P.

    2006-01-01

    In this paper, we suggest a new importance sampling scheme to improve a particle filtering based tracking process. This scheme relies on exploitation of motion segmentation. More precisely, we propagate hypotheses from particle filtering to blobs of similar motion to target. Hence, search is driven toward regions of interest in the state space and prediction is more accurate. We also propose to exploit segmentation to update target model. Once the moving target has been identified, a representative model is learnt from its spatial support. We refer to this model in the correction step of the tracking process. The importance sampling scheme and the strategy to update target model improve the performance of particle filtering in complex situations of occlusions compared to a simple Bootstrap approach as shown by our experiments on real fish tank sequences.

  13. Estimate the Electromechanical States Using Particle Filtering and Smoothing

    SciTech Connect

    Meng, Da; Zhou, Ning; Lu, Shuai; Lin, Guang

    2012-07-22

    Accurate knowledge of electromechanical states is critical for efficient and reliable control of a power system. This paper proposes a particle filtering approach to estimate the electromechanical states of power systems from Phasor Measurement Unit (PMU) data. Without having to go through laborious linearization procedure, the proposed particle filtering techniques can estimate states of a complex power system, which is often non-linear and has non-Gaussian noise. The proposed method is evaluated using a multi-machine system with both large and small disturbances. Sensitivity studies of the dynamic state estimation performance are also presented to show the robustness of the proposed method. The inherent decoupling properties of particle filtering make it highly scalable and the potential to reduce computational time through parallel implementation is very promising.

  14. Multiple states and joint objects particle filter for eye tracking

    NASA Astrophysics Data System (ADS)

    Xiong, Jin; Jiang, Zhaohui; Liu, Junwei; Feng, Huanqing

    2007-11-01

    Recent works have proven that the particle filter is a powerful tracking technique for non-linear and non-Gaussian estimation problem. This paper presents an extension algorithm based on the color-based particle filter framework, which is applicable for complex eye tracking because of two main innovations. Firstly, an employment of an extra discrete-value variable and its associated transition probability matrix (TPM) makes it feasible in tracking multiple states of the eye during blinking. Secondly, the joint-object thought used in state vector eliminates the distraction from eyes to each other. The experimental results illustrate that the proposed algorithm is efficient for eye tracking.

  15. Identifying Optimal Measurement Subspace for the Ensemble Kalman Filter

    SciTech Connect

    Zhou, Ning; Huang, Zhenyu; Welch, Greg; Zhang, J.

    2012-05-24

    To reduce the computational load of the ensemble Kalman filter while maintaining its efficacy, an optimization algorithm based on the generalized eigenvalue decomposition method is proposed for identifying the most informative measurement subspace. When the number of measurements is large, the proposed algorithm can be used to make an effective tradeoff between computational complexity and estimation accuracy. This algorithm also can be extended to other Kalman filters for measurement subspace selection.

  16. Optimal filtering methods to structural damage estimation under ground excitation.

    PubMed

    Hsieh, Chien-Shu; Liaw, Der-Cherng; Lin, Tzu-Hsuan

    2013-01-01

    This paper considers the problem of shear building damage estimation subject to earthquake ground excitation using the Kalman filtering approach. The structural damage is assumed to take the form of reduced elemental stiffness. Two damage estimation algorithms are proposed: one is the multiple model approach via the optimal two-stage Kalman estimator (OTSKE), and the other is the robust two-stage Kalman filter (RTSKF), an unbiased minimum-variance filtering approach to determine the locations and extents of the damage stiffness. A numerical example of a six-storey shear plane frame structure subject to base excitation is used to illustrate the usefulness of the proposed results. PMID:24453869

  17. Optimal Filtering Methods to Structural Damage Estimation under Ground Excitation

    PubMed Central

    Hsieh, Chien-Shu; Liaw, Der-Cherng; Lin, Tzu-Hsuan

    2013-01-01

    This paper considers the problem of shear building damage estimation subject to earthquake ground excitation using the Kalman filtering approach. The structural damage is assumed to take the form of reduced elemental stiffness. Two damage estimation algorithms are proposed: one is the multiple model approach via the optimal two-stage Kalman estimator (OTSKE), and the other is the robust two-stage Kalman filter (RTSKF), an unbiased minimum-variance filtering approach to determine the locations and extents of the damage stiffness. A numerical example of a six-storey shear plane frame structure subject to base excitation is used to illustrate the usefulness of the proposed results. PMID:24453869

  18. Design and performance optimization of fiber optic adaptive filters.

    PubMed

    Paparao, P; Ghosh, A; Allen, S D

    1991-05-10

    There is a great need for easy-to-fabricate and versatile fiber optic signal processing systems in which optical fibers are used for the delay and storage of wideband guided lightwave signals. We describe the design of the least-mean-square algorithm-based fiber optic adaptive filters for processing guided lightwave signals in real time. Fiber optic adaptive filters can learn to change their parameters or to process a set of characteristics of the input signal. In our realization we employ as few electronic devices as possible and use optical computation to utilize the advantages of optics in the processing speed, parallelism, and interconnection. Many schemes for optical adaptive filtering of electronic signals are available in the literature. The new optical adaptive filters described in this paper are for optical processing of guided lightwave signals, not electronic signals. We analyzed the convergence or learning characteristics of the adaptive filtering process as a function of the filter parameters and the fiber optic hardware errors. From this analysis we found that the effects of the optical round-off errors and noise can be reduced, and the learning speed can be comparatively increased in our design through an optimal selection of the filter parameters. A general knowledge of the fiber optic hardware, the statistics of the lightwave signal, and the desired goal of the adaptive processing are enough for this optimum selection of the parameters. Detailed computer simulations validate the theoretical results of performance optimization. PMID:20700365

  19. Optimal Recursive Digital Filters for Active Bending Stabilization

    NASA Technical Reports Server (NTRS)

    Orr, Jeb S.

    2013-01-01

    In the design of flight control systems for large flexible boosters, it is common practice to utilize active feedback control of the first lateral structural bending mode so as to suppress transients and reduce gust loading. Typically, active stabilization or phase stabilization is achieved by carefully shaping the loop transfer function in the frequency domain via the use of compensating filters combined with the frequency response characteristics of the nozzle/actuator system. In this paper we present a new approach for parameterizing and determining optimal low-order recursive linear digital filters so as to satisfy phase shaping constraints for bending and sloshing dynamics while simultaneously maximizing attenuation in other frequency bands of interest, e.g. near higher frequency parasitic structural modes. By parameterizing the filter directly in the z-plane with certain restrictions, the search space of candidate filter designs that satisfy the constraints is restricted to stable, minimum phase recursive low-pass filters with well-conditioned coefficients. Combined with optimal output feedback blending from multiple rate gyros, the present approach enables rapid and robust parametrization of autopilot bending filters to attain flight control performance objectives. Numerical results are presented that illustrate the application of the present technique to the development of rate gyro filters for an exploration-class multi-engined space launch vehicle.

  20. Sequential Bearings-Only-Tracking Initiation with Particle Filtering Method

    PubMed Central

    Hao, Chengpeng

    2013-01-01

    The tracking initiation problem is examined in the context of autonomous bearings-only-tracking (BOT) of a single appearing/disappearing target in the presence of clutter measurements. In general, this problem suffers from a combinatorial explosion in the number of potential tracks resulted from the uncertainty in the linkage between the target and the measurement (a.k.a the data association problem). In addition, the nonlinear measurements lead to a non-Gaussian posterior probability density function (pdf) in the optimal Bayesian sequential estimation framework. The consequence of this nonlinear/non-Gaussian context is the absence of a closed-form solution. This paper models the linkage uncertainty and the nonlinear/non-Gaussian estimation problem jointly with solid Bayesian formalism. A particle filtering (PF) algorithm is derived for estimating the model's parameters in a sequential manner. Numerical results show that the proposed solution provides a significant benefit over the most commonly used methods, IPDA and IMMPDA. The posterior Cramér-Rao bounds are also involved for performance evaluation. PMID:24453865

  1. Optimization of filtering schemes for broadband astro-combs.

    PubMed

    Chang, Guoqing; Li, Chih-Hao; Phillips, David F; Szentgyorgyi, Andrew; Walsworth, Ronald L; Krtner, Franz X

    2012-10-22

    To realize a broadband, large-line-spacing astro-comb, suitable for wavelength calibration of astrophysical spectrographs, from a narrowband, femtosecond laser frequency comb ("source-comb"), one must integrate the source-comb with three additional components: (1) one or more filter cavities to multiply the source-comb's repetition rate and thus line spacing; (2) power amplifiers to boost the power of pulses from the filtered comb; and (3) highly nonlinear optical fiber to spectrally broaden the filtered and amplified narrowband frequency comb. In this paper we analyze the interplay of Fabry-Perot (FP) filter cavities with power amplifiers and nonlinear broadening fiber in the design of astro-combs optimized for radial-velocity (RV) calibration accuracy. We present analytic and numeric models and use them to evaluate a variety of FP filtering schemes (labeled as identical, co-prime, fraction-prime, and conjugate cavities), coupled to chirped-pulse amplification (CPA). We find that even a small nonlinear phase can reduce suppression of filtered comb lines, and increase RV error for spectrograph calibration. In general, filtering with two cavities prior to the CPA fiber amplifier outperforms an amplifier placed between the two cavities. In particular, filtering with conjugate cavities is able to provide <1 cm/s RV calibration error with >300 nm wavelength coverage. Such superior performance will facilitate the search for and characterization of Earth-like exoplanets, which requires <10 cm/s RV calibration error. PMID:23187265

  2. A Novel Particle Swarm Optimization Algorithm for Global Optimization

    PubMed Central

    Wang, Chun-Feng; Liu, Kui

    2016-01-01

    Particle Swarm Optimization (PSO) is a recently developed optimization method, which has attracted interest of researchers in various areas due to its simplicity and effectiveness, and many variants have been proposed. In this paper, a novel Particle Swarm Optimization algorithm is presented, in which the information of the best neighbor of each particle and the best particle of the entire population in the current iteration is considered. Meanwhile, to avoid premature, an abandoned mechanism is used. Furthermore, for improving the global convergence speed of our algorithm, a chaotic search is adopted in the best solution of the current iteration. To verify the performance of our algorithm, standard test functions have been employed. The experimental results show that the algorithm is much more robust and efficient than some existing Particle Swarm Optimization algorithms. PMID:26955387

  3. Nonlinear Statistical Signal Processing: A Particle Filtering Approach

    SciTech Connect

    Candy, J

    2007-09-19

    A introduction to particle filtering is discussed starting with an overview of Bayesian inference from batch to sequential processors. Once the evolving Bayesian paradigm is established, simulation-based methods using sampling theory and Monte Carlo realizations are discussed. Here the usual limitations of nonlinear approximations and non-gaussian processes prevalent in classical nonlinear processing algorithms (e.g. Kalman filters) are no longer a restriction to perform Bayesian inference. It is shown how the underlying hidden or state variables are easily assimilated into this Bayesian construct. Importance sampling methods are then discussed and shown how they can be extended to sequential solutions implemented using Markovian state-space models as a natural evolution. With this in mind, the idea of a particle filter, which is a discrete representation of a probability distribution, is developed and shown how it can be implemented using sequential importance sampling/resampling methods. Finally, an application is briefly discussed comparing the performance of the particle filter designs with classical nonlinear filter implementations.

  4. A local particle filter for high dimensional geophysical systems

    NASA Astrophysics Data System (ADS)

    Penny, S. G.; Miyoshi, T.

    2015-12-01

    A local particle filter (LPF) is introduced that outperforms traditional ensemble Kalman filters in highly nonlinear/non-Gaussian scenarios, both in accuracy and computational cost. The standard Sampling Importance Resampling (SIR) particle filter is augmented with an observation-space localization approach, for which an independent analysis is computed locally at each gridpoint. The deterministic resampling approach of Kitagawa is adapted for application locally and combined with interpolation of the analysis weights to smooth the transition between neighboring points. Gaussian noise is applied with magnitude equal to the local analysis spread to prevent particle degeneracy while maintaining the estimate of the growing dynamical instabilities. The approach is validated against the Local Ensemble Transform Kalman Filter (LETKF) using the 40-variable Lorenz-96 model. The results show that: (1) the accuracy of LPF surpasses LETKF as the forecast length increases (thus increasing the degree of nonlinearity), (2) the cost of LPF is significantly lower than LETKF as the ensemble size increases, and (3) LPF prevents filter divergence experienced by LETKF in cases with non-Gaussian observation error distributions.

  5. Lubricant wear particle analysis by filter patch extraction

    SciTech Connect

    Smart, C.L.

    1996-07-01

    Lubricating Oil Analysis (LOA) has become an important part of a comprehensive Reliability Centered Maintenance (RCM) program. However, knowing the condition of the lubricant alone does not provide a complete description of equipment reliability. Condition monitoring for equipment can be accomplished through Wear Particle Analysis (WPA). This usually involves separating suspended materials and wear products from the lubricant by magnetic (ferrographic) means. This paper will present a simple, low-cost, alternate method of particle acquisition called Filter Patch Extraction (FPE). This method removes solids, regardless of their composition, from the lubricant by vacuum filtration and deposits them onto a filter for microscopic examination similar to that of analytical ferrography. A large filter pore size retains suspended materials and permits rapid filtration of large volumes of lubricant thereby increasing the accuracy of the wear and cleanliness profile that can be established for a given machine. Qualitative trending of equipment wear and lubricant system cleanliness are easily performed with FPE. Equipment condition is determined by then characterizing the metal particles which are recovered. Examined filters are easily archived in filter holders for future reference. Equipment for FPE is inexpensive and readily available. The technique is field-portable, allowing WPA to be performed on-site, eliminating delays with remote laboratories while building customer participation and support. There are numerous advantages for using FPE in a machine condition monitoring program.

  6. Assessment of optimally filtered recent geodetic mean dynamic topographies

    NASA Astrophysics Data System (ADS)

    Siegismund, F.

    2013-01-01

    AbstractRecent geoids from the Gravity Recovery and Climate Experiment (GRACE) and the Gravity field and steady state Ocean Circulation Explorer satellite mission (GOCE) contain useful short-scale information for the construction of a geodetic ocean mean dynamic topography (MDT). The geodetic MDT is obtained from subtracting the geoid from a mean sea surface (MSS) as measured by satellite altimetry. A gainful use of the MDT and an adequate assessment needs an <span class="hlt">optimal</span> <span class="hlt">filtering</span>. This is accomplished here by defining a cutoff length scale dmax for the geoid and applying a Gaussian <span class="hlt">filter</span> with half-width radius r on the MDT. A series of MDTs (GRACE, GOCE, and combined satellite-only (GOCO) solutions) is tested, using different sets of <span class="hlt">filter</span> parameters dmax and r. <span class="hlt">Optimal</span> global and regional dependent <span class="hlt">filter</span> parameters are estimated. To find <span class="hlt">optimal</span> parameters and to assess the resulting MDTs, the geostrophic surface currents induced by the <span class="hlt">filtered</span> geodetic MDT are compared to corrected near-surface currents obtained from the Global Drifter Program (GDP). The global <span class="hlt">optimal</span> cutoff degree and order (d/o) dmax (half-width radius r of the spatial Gaussian <span class="hlt">filter</span>) is 160 (1.1°) for GRACE; 180 (1.1-1.2°) for 1st releases of GOCE (time- and space-wise methods) and GOCO models; and 210 (1.0 degree) for 2nd and 3rd releases of GOCE and GOCO models. The cutoff d/o is generally larger (smaller) and the <span class="hlt">filter</span> length smaller (larger) for regions with strong, small-scale (slow, broad scale) currents. The smallest deviations from the drifter data are obtained with the GOCO03s geoid model, although deviations of other models are only slightly higher.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9406E..06W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9406E..06W"><span id="translatedtitle">Localization using omnivision-based manifold <span class="hlt">particle</span> <span class="hlt">filters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wong, Adelia; Yousefhussien, Mohammed; Ptucha, Raymond</p> <p>2015-01-01</p> <p>Developing precise and low-cost spatial localization algorithms is an essential component for autonomous navigation systems. Data collection must be of sufficient detail to distinguish unique locations, yet coarse enough to enable real-time processing. Active proximity sensors such as sonar and rangefinders have been used for interior localization, but sonar sensors are generally coarse and rangefinders are generally expensive. Passive sensors such as video cameras are low cost and feature-rich, but suffer from high dimensions and excessive bandwidth. This paper presents a novel approach to indoor localization using a low cost video camera and spherical mirror. Omnidirectional captured images undergo normalization and unwarping to a canonical representation more suitable for processing. Training images along with indoor maps are fed into a semi-supervised linear extension of graph embedding manifold learning algorithm to learn a low dimensional surface which represents the interior of a building. The manifold surface descriptor is used as a semantic signature for <span class="hlt">particle</span> <span class="hlt">filter</span> localization. Test frames are conditioned, mapped to a low dimensional surface, and then localized via an adaptive <span class="hlt">particle</span> <span class="hlt">filter</span> algorithm. These <span class="hlt">particles</span> are temporally <span class="hlt">filtered</span> for the final localization estimate. The proposed method, termed omnivision-based manifold <span class="hlt">particle</span> <span class="hlt">filters</span>, reduces convergence lag and increases overall efficiency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110016536','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110016536"><span id="translatedtitle">Model Adaptation for Prognostics in a <span class="hlt">Particle</span> <span class="hlt">Filtering</span> Framework</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Saha, Bhaskar; Goebel, Kai Frank</p> <p>2011-01-01</p> <p>One of the key motivating factors for using <span class="hlt">particle</span> <span class="hlt">filters</span> for prognostics is the ability to include model parameters as part of the state vector to be estimated. This performs model adaptation in conjunction with state tracking, and thus, produces a tuned model that can used for long term predictions. This feature of <span class="hlt">particle</span> <span class="hlt">filters</span> works in most part due to the fact that they are not subject to the "curse of dimensionality", i.e. the exponential growth of computational complexity with state dimension. However, in practice, this property holds for "well-designed" <span class="hlt">particle</span> <span class="hlt">filters</span> only as dimensionality increases. This paper explores the notion of wellness of design in the context of predicting remaining useful life for individual discharge cycles of Li-ion batteries. Prognostic metrics are used to analyze the tradeoff between different model designs and prediction performance. Results demonstrate how sensitivity analysis may be used to arrive at a well-designed prognostic model that can take advantage of the model adaptation properties of a <span class="hlt">particle</span> <span class="hlt">filter</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EJASP2013..148G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EJASP2013..148G"><span id="translatedtitle">Fast, parallel implementation of <span class="hlt">particle</span> <span class="hlt">filtering</span> on the GPU architecture</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gelencsér-Horváth, Anna; Tornai, Gábor János; Horváth, András; Cserey, György</p> <p>2013-12-01</p> <p>In this paper, we introduce a modified cellular <span class="hlt">particle</span> <span class="hlt">filter</span> (CPF) which we mapped on a graphics processing unit (GPU) architecture. We developed this <span class="hlt">filter</span> adaptation using a state-of-the art CPF technique. Mapping this <span class="hlt">filter</span> realization on a highly parallel architecture entailed a shift in the logical representation of the <span class="hlt">particles</span>. In this process, the original two-dimensional organization is reordered as a one-dimensional ring topology. We proposed a proof-of-concept measurement on two models with an NVIDIA Fermi architecture GPU. This design achieved a 411- μs kernel time per state and a 77-ms global running time for all states for 16,384 <span class="hlt">particles</span> with a 256 neighbourhood size on a sequence of 24 states for a bearing-only tracking model. For a commonly used benchmark model at the same configuration, we achieved a 266- μs kernel time per state and a 124-ms global running time for all 100 states. Kernel time includes random number generation on the GPU with curand. These results attest to the effective and fast use of the <span class="hlt">particle</span> <span class="hlt">filter</span> in high-dimensional, real-time applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4542024','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4542024"><span id="translatedtitle">Multiswarm <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> with Transfer of the Best <span class="hlt">Particle</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wei, Xiao-peng; Zhang, Jian-xia; Zhou, Dong-sheng; Zhang, Qiang</p> <p>2015-01-01</p> <p>We propose an improved algorithm, for a multiswarm <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> with transfer of the best <span class="hlt">particle</span> called BMPSO. In the proposed algorithm, we introduce parasitism into the standard <span class="hlt">particle</span> swarm algorithm (PSO) in order to balance exploration and exploitation, as well as enhancing the capacity for global search to solve nonlinear <span class="hlt">optimization</span> problems. First, the best <span class="hlt">particle</span> guides other <span class="hlt">particles</span> to prevent them from being trapped by local optima. We provide a detailed description of BMPSO. We also present a diversity analysis of the proposed BMPSO, which is explained based on the Sphere function. Finally, we tested the performance of the proposed algorithm with six standard test functions and an engineering problem. Compared with some other algorithms, the results showed that the proposed BMPSO performed better when applied to the test functions and the engineering problem. Furthermore, the proposed BMPSO can be applied to other nonlinear <span class="hlt">optimization</span> problems. PMID:26345200</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19970023609&hterms=1609&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2526%25231609','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19970023609&hterms=1609&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2526%25231609"><span id="translatedtitle"><span class="hlt">Optimal</span> Correlation <span class="hlt">Filters</span> for Images with Signal-Dependent Noise</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Downie, John D.; Walkup, John F.</p> <p>1994-01-01</p> <p>We address the design of <span class="hlt">optimal</span> correlation <span class="hlt">filters</span> for pattern detection and recognition in the presence of signal-dependent image noise sources. The particular examples considered are film-grain noise and speckle. Two basic approaches are investigated: (1) deriving the <span class="hlt">optimal</span> matched <span class="hlt">filters</span> for the signal-dependent noise models and comparing their performances with those derived for traditional signal-independent noise models and (2) first nonlinearly transforming the signal-dependent noise to signal-independent noise followed by the use of a classical <span class="hlt">filter</span> matched to the transformed signal. We present both theoretical and computer simulation results that demonstrate the generally superior performance of the second approach in terms of the correlation peak signal-to-noise ratio.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4190536','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4190536"><span id="translatedtitle">Na-Faraday rotation <span class="hlt">filtering</span>: The <span class="hlt">optimal</span> point</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kiefer, Wilhelm; Löw, Robert; Wrachtrup, Jörg; Gerhardt, Ilja</p> <p>2014-01-01</p> <p>Narrow-band optical <span class="hlt">filtering</span> is required in many spectroscopy applications to suppress unwanted background light. One example is quantum communication where the fidelity is often limited by the performance of the optical <span class="hlt">filters</span>. This limitation can be circumvented by utilizing the GHz-wide features of a Doppler broadened atomic gas. The anomalous dispersion of atomic vapours enables spectral <span class="hlt">filtering</span>. These, so-called, Faraday anomalous dispersion optical <span class="hlt">filters</span> (FADOFs) can be by far better than any commercial <span class="hlt">filter</span> in terms of bandwidth, transition edge and peak transmission. We present a theoretical and experimental study on the transmission properties of a sodium vapour based FADOF with the aim to find the best combination of optical rotation and intrinsic loss. The relevant parameters, such as magnetic field, temperature, the related optical depth, and polarization state are discussed. The non-trivial interplay of these quantities defines the net performance of the <span class="hlt">filter</span>. We determine analytically the <span class="hlt">optimal</span> working conditions, such as transmission and the signal to background ratio and validate the results experimentally. We find a single global optimum for one specific optical path length of the <span class="hlt">filter</span>. This can now be applied to spectroscopy, guide star applications, or sensing. PMID:25298251</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010SPIE.7539E..09T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010SPIE.7539E..09T"><span id="translatedtitle">Object tracking by co-trained classifiers and <span class="hlt">particle</span> <span class="hlt">filters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tang, Liang; Li, Shanqing; Liu, Keyan; Wang, Lei</p> <p>2010-01-01</p> <p>This paper presents an online object tracking method, in which co-training and <span class="hlt">particle</span> <span class="hlt">filters</span> algorithms cooperate and complement each other for robust and effective tracking. Under framework of <span class="hlt">particle</span> <span class="hlt">filters</span>, the semi-supervised cotraining algorithm is adopted to construct, on-line update, and mutually boost two complementary object classifiers, which consequently improves discriminant ability of <span class="hlt">particles</span> and its adaptability to appearance variants caused by illumination changing, pose verying, camera shaking, and occlusion. Meanwhile, to make sampling procedure more efficient, knowledge from coarse confidence maps and spatial-temporal constraints are introduced by importance sampling. It improves not only the accuracy and efficiency of sampling procedure, but also provides more reliable training samples for co-training. Experimental results verify the effectiveness and robustness of our method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010SPIE.7744E..1MS','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010SPIE.7744E..1MS"><span id="translatedtitle">A refined <span class="hlt">particle</span> <span class="hlt">filter</span> method for contour tracking</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Xin; Yao, Hongxun; Zhang, Shengping</p> <p>2010-07-01</p> <p>Traditional <span class="hlt">particle</span> <span class="hlt">filter</span> which uses simple geometric shapes for representation cannot track objects with complex shape accurately. In this paper, we propose a refined <span class="hlt">particle</span> <span class="hlt">filter</span> method for contour tracking based on a binary level set model. In contrast with other previous work, the computational efficiency is greatly improved due to the simple form of the level set function. In addition, we perform curve evolution in the update step to make good use of the observation at current time. Finally, we consider some appearance information as well as the energy function to measure the weight for <span class="hlt">particles</span>, which can identify the target more accurately. Experiment results on several challenging video sequences have verified the proposed algorithm is efficient and effective in many complicated scenes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.H23H..02P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.H23H..02P"><span id="translatedtitle">Ensemble Kalman <span class="hlt">Filter</span> vs <span class="hlt">Particle</span> <span class="hlt">Filter</span> in a Physically Based Coupled Model of Surface-Subsurface Flow (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Putti, M.; Camporese, M.; Pasetto, D.</p> <p>2010-12-01</p> <p>Data assimilation (DA) has recently received growing interest by the hydrological modeling community due to its capability to merge observations into model prediction. Among the many DA methods available, the Ensemble Kalman <span class="hlt">Filter</span> (EnKF) and the <span class="hlt">Particle</span> <span class="hlt">Filter</span> (PF) are suitable alternatives for applications to detailed physically-based hydrological models. For each assimilation period, both methods use a Monte Carlo approach to approximate the state probability distribution (in terms of mean and covariance matrix) by a finite number of independent model trajectories, also called <span class="hlt">particles</span> or realizations. The two approaches differ in the way the <span class="hlt">filtering</span> distribution is evaluated. EnKF implements the classical Kalman <span class="hlt">filter</span>, <span class="hlt">optimal</span> only for linear dynamics and Gaussian error statistics. <span class="hlt">Particle</span> <span class="hlt">filters</span>, instead, use directly the recursive formula of the sequential Bayesian framework and approximate the posterior probability distributions by means of appropriate weights associated to each realization. We use the Sequential Importance Resampling (SIR) technique, which retains only the most probable <span class="hlt">particles</span>, in practice the trajectories closest in a statistical sense to the observations, and duplicates them when needed. In contrast to EnKF, <span class="hlt">particle</span> <span class="hlt">filters</span> make no assumptions on the form of the prior distribution of the model state, and convergence to the true state is ensured for large enough ensemble size. In this study EnKF and PF have been implemented in a physically based catchment simulator that couples a three-dimensional finite element Richards equation solver with a finite difference diffusion wave approximation based on a digital elevation data for surface water dynamics. We report on the retrieval performance of the two schemes using a three-dimensional tilted v-catchment synthetic test case in which multi-source observations are assimilated (pressure head, soil moisture, and streamflow data). The comparison between the results of the two approaches allows to discuss some of the strengths and weaknesses, both physical and numerical, of EnKF and PF and to learn the implications related to the choice of the statistics used to build the ensemble of realizations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SPIE.7383E..0YL','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SPIE.7383E..0YL"><span id="translatedtitle">Multi-target track based on mixtures of <span class="hlt">particle</span> <span class="hlt">filtering</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Shaojun; Zhu, Zhenfu</p> <p>2009-07-01</p> <p>For the problem of detecting and tracking a varying number of dim small target in IR image sequences, multitarget track-before-detect approach based on mixture models of probability densities is proposed and mixtures of t distribution <span class="hlt">particle</span> <span class="hlt">filters</span> (MTPF) are developed for the implementation of the proposed approach in this paper. The existence of each tracked target is detected by using the sequential likelihood ratio test estimated by the output of component <span class="hlt">particle</span> <span class="hlt">filter</span>. New targets are detected by the appearance probabilities in the discrete occupancy grid in the image frame. The algorithm explicitly handles the instantiation and removal of <span class="hlt">filters</span> in case new objects enter the scene or previously tracked objects are removed. The proposed approach overcomes the curse of dimensionality by estimating each target state independently by using separate <span class="hlt">particle</span> <span class="hlt">filter</span> and avoids the exponential increase in the estimation complexity. Simulation experiments illustrated that the MTPF algorithm can detect and track the variable number of dim small targets in the IR images, and simultaneously detect the disappearance and appearance of targets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26391486','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26391486"><span id="translatedtitle"><span class="hlt">Optimal</span> fractional delay-IIR <span class="hlt">filter</span> design using cuckoo search algorithm.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kumar, Manjeet; Rawat, Tarun Kumar</p> <p>2015-11-01</p> <p>This paper applied a novel global meta-heuristic <span class="hlt">optimization</span> algorithm, cuckoo search algorithm (CSA) to determine <span class="hlt">optimal</span> coefficients of a fractional delay-infinite impulse response (FD-IIR) <span class="hlt">filter</span> and trying to meet the ideal frequency response characteristics. Since fractional delay-IIR <span class="hlt">filter</span> design is a multi-modal <span class="hlt">optimization</span> problem, it cannot be computed efficiently using conventional gradient based <span class="hlt">optimization</span> techniques. A weighted least square (WLS) based fitness function is used to improve the performance to a great extent. FD-IIR <span class="hlt">filters</span> of different orders have been designed using the CSA. The simulation results of the proposed CSA based approach have been compared to those of well accepted evolutionary algorithms like Genetic Algorithm (GA) and <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO). The performance of the CSA based FD-IIR <span class="hlt">filter</span> is superior to those obtained by GA and PSO. The simulation and statistical results affirm that the proposed approach using CSA outperforms GA and PSO, not only in the convergence rate but also in <span class="hlt">optimal</span> performance of the designed FD-IIR <span class="hlt">filter</span> (i.e., smaller magnitude error, smaller phase error, higher percentage improvement in magnitude and phase error, fast convergence rate). The absolute magnitude and phase error obtained for the designed 5th order FD-IIR <span class="hlt">filter</span> are as low as 0.0037 and 0.0046, respectively. The percentage improvement in magnitude error for CSA based 5th order FD-IIR design with respect to GA and PSO are 80.93% and 74.83% respectively, and phase error are 76.04% and 71.25%, respectively. PMID:26391486</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15285252','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15285252"><span id="translatedtitle">Degeneracy, frequency response and <span class="hlt">filtering</span> in IMRT <span class="hlt">optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Llacer, Jorge; Agazaryan, Nzhde; Solberg, Timothy D; Promberger, Claus</p> <p>2004-07-01</p> <p>This paper attempts to provide an answer to some questions that remain either poorly understood, or not well documented in the literature, on basic issues related to intensity modulated radiation therapy (IMRT). The questions examined are: the relationship between degeneracy and frequency response of <span class="hlt">optimizations</span>, effects of initial beamlet fluence assignment and stopping point, what does <span class="hlt">filtering</span> of an <span class="hlt">optimized</span> beamlet map actually do and how could image analysis help to obtain better <span class="hlt">optimizations</span>? Two target functions are studied, a quadratic cost function and the log likelihood function of the dynamically penalized likelihood (DPL) algorithm. The algorithms used are the conjugate gradient, the stochastic adaptive simulated annealing and the DPL. One simple phantom is used to show the development of the analysis tools used and two clinical cases of medium and large dose matrix size (a meningioma and a prostate) are studied in detail. The conclusions reached are that the high number of iterations that is needed to avoid degeneracy is not warranted in clinical practice, as the quality of the <span class="hlt">optimizations</span>, as judged by the DVHs and dose distributions obtained, does not improve significantly after a certain point. It is also shown that the optimum initial beamlet fluence assignment for analytical iterative algorithms is a uniform distribution, but such an assignment does not help a stochastic method of <span class="hlt">optimization</span>. Stopping points for the studied algorithms are discussed and the deterioration of DVH characteristics with <span class="hlt">filtering</span> is shown to be partially recoverable by the use of space-variant <span class="hlt">filtering</span> techniques. PMID:15285252</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004PMB....49.2853L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004PMB....49.2853L"><span id="translatedtitle">Degeneracy, frequency response and <span class="hlt">filtering</span> in IMRT <span class="hlt">optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Llacer, Jorge; Agazaryan, Nzhde; Solberg, Timothy D.; Promberger, Claus</p> <p>2004-07-01</p> <p>This paper attempts to provide an answer to some questions that remain either poorly understood, or not well documented in the literature, on basic issues related to intensity modulated radiation therapy (IMRT). The questions examined are: the relationship between degeneracy and frequency response of <span class="hlt">optimizations</span>, effects of initial beamlet fluence assignment and stopping point, what does <span class="hlt">filtering</span> of an <span class="hlt">optimized</span> beamlet map actually do and how could image analysis help to obtain better <span class="hlt">optimizations</span>? Two target functions are studied, a quadratic cost function and the log likelihood function of the dynamically penalized likelihood (DPL) algorithm. The algorithms used are the conjugate gradient, the stochastic adaptive simulated annealing and the DPL. One simple phantom is used to show the development of the analysis tools used and two clinical cases of medium and large dose matrix size (a meningioma and a prostate) are studied in detail. The conclusions reached are that the high number of iterations that is needed to avoid degeneracy is not warranted in clinical practice, as the quality of the <span class="hlt">optimizations</span>, as judged by the DVHs and dose distributions obtained, does not improve significantly after a certain point. It is also shown that the optimum initial beamlet fluence assignment for analytical iterative algorithms is a uniform distribution, but such an assignment does not help a stochastic method of <span class="hlt">optimization</span>. Stopping points for the studied algorithms are discussed and the deterioration of DVH characteristics with <span class="hlt">filtering</span> is shown to be partially recoverable by the use of space-variant <span class="hlt">filtering</span> techniques.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9411E..0PG','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9411E..0PG"><span id="translatedtitle"><span class="hlt">Optimal</span> color image restoration: Wiener <span class="hlt">filter</span> and quaternion Fourier transform</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grigoryan, Artyom M.; Agaian, Sos S.</p> <p>2015-03-01</p> <p>In this paper, we consider the model of quaternion signal degradation when the signal is convoluted and an additive noise is added. The classical model of such a model leads to the solution of the <span class="hlt">optimal</span> Wiener <span class="hlt">filter</span>, where the <span class="hlt">optimality</span> with respect to the mean square error. The characteristic of this <span class="hlt">filter</span> can be found in the frequency domain by using the Fourier transform. For quaternion signals, the inverse problem is complicated by the fact that the quaternion arithmetic is not commutative. The quaternion Fourier transform does not map the convolution to the operation of multiplication. In this paper, we analyze the linear model of the signal and image degradation with an additive independent noise and the <span class="hlt">optimal</span> filtration of the signal and images in the frequency domain and in the quaternion space.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...820...51P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...820...51P"><span id="translatedtitle"><span class="hlt">Optimized</span> Beam Sculpting with Generalized Fringe-rate <span class="hlt">Filters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parsons, Aaron R.; Liu, Adrian; Ali, Zaki S.; Cheng, Carina</p> <p>2016-03-01</p> <p>We generalize the technique of fringe-rate <span class="hlt">filtering</span>, whereby visibilities measured by a radio interferometer are re-weighted according to their temporal variation. As the Earth rotates, radio sources traverse through an interferometer’s fringe pattern at rates that depend on their position on the sky. Capitalizing on this geometric interpretation of fringe rates, we employ time-domain convolution kernels to enact fringe-rate <span class="hlt">filters</span> that sculpt the effective primary beam of antennas in an interferometer. As we show, beam sculpting through fringe-rate <span class="hlt">filtering</span> can be used to <span class="hlt">optimize</span> measurements for a variety of applications, including mapmaking, minimizing polarization leakage, suppressing instrumental systematics, and enhancing the sensitivity of power-spectrum measurements. We show that fringe-rate <span class="hlt">filtering</span> arises naturally in minimum variance treatments of many of these problems, enabling <span class="hlt">optimal</span> visibility-based approaches to analyses of interferometric data that avoid systematics potentially introduced by traditional approaches such as imaging. Our techniques have recently been demonstrated in Ali et al., where new upper limits were placed on the 21 {cm} power spectrum from reionization, showcasing the ability of fringe-rate <span class="hlt">filtering</span> to successfully boost sensitivity and reduce the impact of systematics in deep observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23434235','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23434235"><span id="translatedtitle">A novel method for retinal vessel tracking using <span class="hlt">particle</span> <span class="hlt">filters</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nayebifar, B; Abrishami Moghaddam, H</p> <p>2013-06-01</p> <p>Extraction of a proper map from the vessel paths in the retinal images is a prerequisite for many applications such as identification. In this paper, we present a new approach based on <span class="hlt">particle</span> <span class="hlt">filtering</span> to determine and locally track the vessel paths in retina. <span class="hlt">Particle</span> <span class="hlt">filter</span> needs to use an acceptable probability density function (PDF) describing the blood vessels which must be provided by the retinal image. For this purpose, the product of the green and blue channels of the RGB retinal images is considered and after a median <span class="hlt">filtering</span> stage, it is used as a PDF for tracking procedure. Then a stage of optic disc localization is performed to localize the starting points around the optic disc. With a proper set of starting points, the iterative tracking procedure initiates. First, a uniform propagation of the <span class="hlt">particles</span> on an annular ring around each point (including starting points or ones determined as central points in the previous iteration) is performed. The <span class="hlt">particle</span> weights are evaluated and accordingly, each <span class="hlt">particle</span> is decided to be inside or outside the vessel. The subsequent stage is to analyze the hypothetical vectors between a central point and each of the inside vessel <span class="hlt">particles</span> to find ones located inside vessel. Afterwards, the <span class="hlt">particles</span> are clustered using quality threshold clustering method. Finally, each cluster introduces a central point for pursuing the tracking procedure in the next iteration. The tracking proceeds towards a bifurcation or the end of the vessels. We introduced two criteria: automatic/manually tracked ratio (AMTR) and false/manually tracked ratio (FMTR) for evaluating the tracking results. Apart from the labeling accuracy, the average values of AMTR and FMTR were 0.7746 and 0.2091, respectively. The proposed method successfully deals with the bifurcations with robustness against noise and tracks the thin vessels. PMID:23434235</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26849867','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26849867"><span id="translatedtitle">Fourier Spectral <span class="hlt">Filter</span> Array for <span class="hlt">Optimal</span> Multispectral Imaging.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jia, Jie; Barnard, Kenneth J; Hirakawa, Keigo</p> <p>2016-04-01</p> <p>Limitations to existing multispectral imaging modalities include speed, cost, range, spatial resolution, and application-specific system designs that lack versatility of the hyperspectral imaging modalities. In this paper, we propose a novel general-purpose single-shot passive multispectral imaging modality. Central to this design is a new type of spectral <span class="hlt">filter</span> array (SFA) based not on the notion of spatially multiplexing narrowband <span class="hlt">filters</span>, but instead aimed at enabling single-shot Fourier transform spectroscopy. We refer to this new SFA pattern as Fourier SFA, and we prove that this design solves the problem of <span class="hlt">optimally</span> sampling the hyperspectral image data. PMID:26849867</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4178918','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4178918"><span id="translatedtitle">Dual Adaptive <span class="hlt">Filtering</span> by <span class="hlt">Optimal</span> Projection Applied to <span class="hlt">Filter</span> Muscle Artifacts on EEG and Comparative Study</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Peyrodie, Laurent; Szurhaj, William; Bolo, Nicolas; Pinti, Antonio; Gallois, Philippe</p> <p>2014-01-01</p> <p>Muscle artifacts constitute one of the major problems in electroencephalogram (EEG) examinations, particularly for the diagnosis of epilepsy, where pathological rhythms occur within the same frequency bands as those of artifacts. This paper proposes to use the method dual adaptive <span class="hlt">filtering</span> by <span class="hlt">optimal</span> projection (DAFOP) to automatically remove artifacts while preserving true cerebral signals. DAFOP is a two-step method. The first step consists in applying the common spatial pattern (CSP) method to two frequency windows to identify the slowest components which will be considered as cerebral sources. The two frequency windows are defined by <span class="hlt">optimizing</span> convolutional <span class="hlt">filters</span>. The second step consists in using a regression method to reconstruct the signal independently within various frequency windows. This method was evaluated by two neurologists on a selection of 114 pages with muscle artifacts, from 20 clinical recordings of awake and sleeping adults, subject to pathological signals and epileptic seizures. A blind comparison was then conducted with the canonical correlation analysis (CCA) method and conventional low-pass <span class="hlt">filtering</span> at 30?Hz. The <span class="hlt">filtering</span> rate was 84.3% for muscle artifacts with a 6.4% reduction of cerebral signals even for the fastest waves. DAFOP was found to be significantly more efficient than CCA and 30?Hz <span class="hlt">filters</span>. The DAFOP method is fast and automatic and can be easily used in clinical EEG recordings. PMID:25298967</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003SPIE.5117..245D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003SPIE.5117..245D"><span id="translatedtitle">System-level <span class="hlt">optimization</span> of baseband <span class="hlt">filters</span> for communication applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Delgado-Restituto, Manuel; Fernandez-Bootello, Juan F.; Rodriguez-Vazquez, Angel</p> <p>2003-04-01</p> <p>In this paper, we present a design approach for the high-level synthesis of programmable continuous-time Gm-C and active-RC <span class="hlt">filters</span> with optimum trade-off among dynamic range, distortion products generation, area consumption and power dissipation, thus meeting the needs of more demanding baseband <span class="hlt">filter</span> realizations. Further, the proposed technique guarantees that under all programming configurations, transconductors (in Gm-C <span class="hlt">filters</span>) and resistors (in active-RC <span class="hlt">filters</span>) as well as capacitors, are related by integer ratios in order to reduce the sensitivity to mismatch of the monolithic implementation. In order to solve the aforementioned trade-off, the <span class="hlt">filter</span> must be properly scaled at each configuration. It means that <span class="hlt">filter</span> node impedances must be conveniently altered so that the noise contribution of each node to the <span class="hlt">filter</span> output be as low as possible, while avoiding that peak amplitudes at such nodes be so high as to drive active circuits into saturation. Additionally, in order to not degrade the distortion performance of the <span class="hlt">filter</span> (in particular, if it is implemented using Gm-C techniques) node impedances can not be scaled independently from each other but restrictions must be imposed according to the principle of nonlinear cancellation. Altogether, the high-level synthesis can be seen as a constrained <span class="hlt">optimization</span> problem where some of the variables, namely, the ratios among similar components, are restricted to discrete values. The proposed approach to accomplish optimum <span class="hlt">filter</span> scaling under all programming configurations, relies on matrix methods for network representation, which allows an easy estimation of performance features such as dynamic range and power dissipation, as well as other network properties such as sensitivity to parameter variations and non-ideal effects of integrators blocks; and the use of a simulated annealing algorithm to explore the design space defined by the transfer and group delay specifications. It must be noted that such design space also includes most common approximation methods and network synthesis approaches as <span class="hlt">optimization</span> variables, in order to make as widespread as possible the search for optimum solutions. The proposed methodology has been partially developed in MATLAB, taking advantage of the routines available in the signal processing and control toolboxes, and C++. The validity of the methodology and companying software will be demonstrated at the Conference and reported in the paper, using as a tailoring example the design of a programmable bank of <span class="hlt">filters</span> for a high-performance powerline modem.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPC.1706b0011L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPC.1706b0011L"><span id="translatedtitle"><span class="hlt">Optimal</span> matched <span class="hlt">filter</span> design for ultrasonic NDE of coarse grain materials</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Minghui; Hayward, Gordon</p> <p>2016-02-01</p> <p>Coarse grain materials are widely used in a variety of key industrial sectors like energy, oil and gas, and aerospace due to their attractive properties. However, when these materials are inspected using ultrasound, the flaw echoes are usually contaminated by high-level, correlated grain noise originating from the material microstructures, which is time-invariant and demonstrates similar spectral characteristics as flaw signals. As a result, the reliable inspection of such materials is highly challenging. In this paper, we present a method for reliable ultrasonic non-destructive evaluation (NDE) of coarse grain materials using matched <span class="hlt">filters</span>, where the <span class="hlt">filter</span> is designed to approximate and match the unknown defect echoes, and a <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO) paradigm is employed to search for the <span class="hlt">optimal</span> parameters in the <span class="hlt">filter</span> response with an objective to maximise the output signal-to-noise ratio (SNR). Experiments with a 128-element 5MHz transducer array on mild steel and INCONEL Alloy 617 samples are conducted, and the results confirm that the SNR of the images is improved by about 10-20 dB if the <span class="hlt">optimized</span> matched <span class="hlt">filter</span> is applied to all the A-scan waveforms prior to image formation. Furthermore, the matched <span class="hlt">filter</span> can be implemented in real-time with low extra computational cost.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AtmEn..95..520W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AtmEn..95..520W"><span id="translatedtitle">Measurement of <span class="hlt">particle</span> sulfate from micro-aethalometer <span class="hlt">filters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Qingqing; Yang, Fumo; Wei, Lianfang; Zheng, Guangjie; Fan, Zhongjie; Rajagopalan, Sanjay; Brook, Robert D.; Duan, Fengkui; He, Kebin; Sun, Yele; Brook, Jeffrey R.</p> <p>2014-10-01</p> <p>The micro-aethalometer (AE51) was designed for high time resolution black carbon (BC) measurements and the process collects <span class="hlt">particles</span> on a <span class="hlt">filter</span> inside the instrument. Here we examine the potential for saving these <span class="hlt">filters</span> for subsequent sulfate (SO42-) measurement. For this purpose, a series lab and field blanks were analyzed to characterize blank levels and variability and then collocated 24-h aerosol sampling was conducted in Beijing with the AE51 and a dual-channel filterpack sampler that collects fine <span class="hlt">particles</span> (PM2.5). AE51 <span class="hlt">filters</span> and the <span class="hlt">filters</span> from the filterpacks sampled for 24 h were extracted with ultrapure water and then analyzed by Ion Chromatography (IC) to determine integrated SO42- concentration. Blank corrections were essential and the estimated detection limit for 24 h AE51 sampling of SO42- was estimated to be 1.4 μg/m3. The SO42- measured from the AE51 based upon blank corrections using batch-average field blank SO42- values was found to be in reasonable agreement with the filterpack results (R2 > 0.87, slope = 1.02) indicating that it is possible to determine both BC and SO42- concentrations using the AE51 in Beijing. This result suggests that future comparison of the relative health impacts of BC and SO42- could be possible when the AE51 is used for personal exposure measurement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007SPIE.6786E..3OG','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007SPIE.6786E..3OG"><span id="translatedtitle">Real time object tracking using adaptive Kalman <span class="hlt">particle</span> <span class="hlt">filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gao, Lin; Tang, Peng; Liu, Zhifang</p> <p>2007-11-01</p> <p>In this paper, a visual object tracking algorithm based on the Kalman <span class="hlt">particle</span> <span class="hlt">filter</span> (KPF) is presented. The KPF uses the Kalman <span class="hlt">filter</span> to generate sophisticated proposal distributions which greatly improving the tracking performance. However, this improvement is at the cost of much extra computation. To accelerate the algorithm, we mend the conventional KPF by adaptively adjusting the number of <span class="hlt">particles</span> during the resampling step. Moreover, in order to improve the robustness of tracker without increasing the computational load, another two modifications is made: firstly, the covariance matrix of Gaussian noise in the dynamic model is dynamically updated according to the accuracy degree of the prediction. Secondly, the similarity measurement is performed by a scheme that adaptively switches the likelihood models. Experimental results demonstrate the efficiency and accuracy of the proposed algorithm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010IEITC..93..336Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010IEITC..93..336Y"><span id="translatedtitle">Marginalized <span class="hlt">Particle</span> <span class="hlt">Filter</span> for Blind Signal Detection with Analog Imperfections</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yoshida, Yuki; Hayashi, Kazunori; Sakai, Hideaki; Bocquet, Wladimir</p> <p></p> <p>Recently, the marginalized <span class="hlt">particle</span> <span class="hlt">filter</span> (MPF) has been applied to blind symbol detection problems over selective fading channels. The MPF can ease the computational burden of the standard <span class="hlt">particle</span> <span class="hlt">filter</span> (PF) while offering better estimates compared with the standard PF. In this paper, we investigate the application of the blind MPF detector to more realistic situations where the systems suffer from analog imperfections which are non-linear signal distortion due to the inaccurate analog circuits in wireless devices. By reformulating the system model using the widely linear representation and employing the auxiliary variable resampling (AVR) technique for estimation of the imperfections, the blind MPF detector is successfully modified to cope with the analog imperfections. The effectiveness of the proposed MPF detector is demonstrated via computer simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007SPIE.6279E..4NW','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007SPIE.6279E..4NW"><span id="translatedtitle">An adaptive mean shift <span class="hlt">particle</span> <span class="hlt">filter</span> for moving objects tracking</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Xun; Zha, Yufei; Bi, Duyan</p> <p>2007-01-01</p> <p>In this paper, we integrate mean shift algorithm into the <span class="hlt">particle</span> <span class="hlt">filter</span> as the proposal distribution, and adaptively modify the tracking step according to the process of mean shift algorithm. It can be used through the searching for the most matching region with the feature, such as color, texture, etc, which should first be drawn from the targets. Experiments show that it is an efficient and powerful method for tracking fast moving objects in clutter even with occlusions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.H41I..07H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.H41I..07H"><span id="translatedtitle">Ensemble Data Assimilation for Streamflow Forecasting: Experiments with Ensemble Kalman <span class="hlt">Filter</span> and <span class="hlt">Particle</span> <span class="hlt">Filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hirpa, F. A.; Gebremichael, M.; Hopson, T. M.; Wojick, R.</p> <p>2011-12-01</p> <p>We present results of data assimilation of ground discharge observation and remotely sensed soil moisture observations into Sacramento Soil Moisture Accounting (SACSMA) model in a small watershed (1593 km2) in Minnesota, the Unites States. Specifically, we perform assimilation experiments with Ensemble Kalman <span class="hlt">Filter</span> (EnKF) and <span class="hlt">Particle</span> <span class="hlt">Filter</span> (PF) in order to improve streamflow forecast accuracy at six hourly time step. The EnKF updates the soil moisture states in the SACSMA from the relative errors of the model and observations, while the PF adjust the weights of the state ensemble members based on the likelihood of the forecast. Results of the improvements of each <span class="hlt">filter</span> over the reference model (without data assimilation) will be presented. Finally, the EnKF and PF are coupled together to further improve the streamflow forecast accuracy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4365407','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4365407"><span id="translatedtitle">Selectively-informed <span class="hlt">particle</span> swarm <span class="hlt">optimization</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gao, Yang; Du, Wenbo; Yan, Gang</p> <p>2015-01-01</p> <p><span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> (PSO) is a nature-inspired algorithm that has shown outstanding performance in solving many realistic problems. In the original PSO and most of its variants all <span class="hlt">particles</span> are treated equally, overlooking the impact of structural heterogeneity on individual behavior. Here we employ complex networks to represent the population structure of swarms and propose a selectively-informed PSO (SIPSO), in which the <span class="hlt">particles</span> choose different learning strategies based on their connections: a densely-connected hub <span class="hlt">particle</span> gets full information from all of its neighbors while a non-hub <span class="hlt">particle</span> with few connections can only follow a single yet best-performed neighbor. Extensive numerical experiments on widely-used benchmark functions show that our SIPSO algorithm remarkably outperforms the PSO and its existing variants in success rate, solution quality, and convergence speed. We also explore the evolution process from a microscopic point of view, leading to the discovery of different roles that the <span class="hlt">particles</span> play in <span class="hlt">optimization</span>. The hub <span class="hlt">particles</span> guide the <span class="hlt">optimization</span> process towards correct directions while the non-hub <span class="hlt">particles</span> maintain the necessary population diversity, resulting in the optimum overall performance of SIPSO. These findings deepen our understanding of swarm intelligence and may shed light on the underlying mechanism of information exchange in natural swarm and flocking behaviors. PMID:25787315</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JMM%26M..15a3506W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JMM%26M..15a3506W"><span id="translatedtitle">Pixelated source <span class="hlt">optimization</span> for optical lithography via <span class="hlt">particle</span> swarm <span class="hlt">optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Lei; Li, Sikun; Wang, Xiangzhao; Yan, Guanyong; Yang, Chaoxing</p> <p>2016-01-01</p> <p>Source <span class="hlt">optimization</span> is one of the key techniques for achieving higher resolution without increasing the complexity of mask design. An efficient source <span class="hlt">optimization</span> approach is proposed on the basis of <span class="hlt">particle</span> swarm <span class="hlt">optimization</span>. The pixelated sources are encoded into <span class="hlt">particles</span>, which are evaluated by using the pattern error as the fitness function. Afterward, the <span class="hlt">optimization</span> is implemented by updating the velocities and positions of these <span class="hlt">particles</span>. This approach is demonstrated using three mask patterns, including a periodic array of contact holes, a vertical line/space design, and a complicated pattern. The pattern errors are reduced by 69.6%, 51.5%, and 40.3%, respectively. Compared with the source <span class="hlt">optimization</span> approach via genetic algorithm, the proposed approach leads to faster convergence while improving the image quality at the same time. Compared with the source <span class="hlt">optimization</span> approach via gradient descent method, the proposed approach does not need the calculation of gradients, and it has a strong adaptation to various lithographic models, fitness functions, and resist models. The robustness of the proposed approach to initial sources is also verified.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/672026','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/672026"><span id="translatedtitle">A multi-dimensional procedure for BNCT <span class="hlt">filter</span> <span class="hlt">optimization</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lille, R.A.</p> <p>1998-02-01</p> <p>An initial version of an <span class="hlt">optimization</span> code utilizing two-dimensional radiation transport methods has been completed. This code is capable of predicting material compositions of a beam tube-<span class="hlt">filter</span> geometry which can be used in a boron neutron capture therapy treatment facility to improve the ratio of the average radiation dose in a brain tumor to that in the healthy tissue surrounding the tumor. The <span class="hlt">optimization</span> algorithm employed by the code is very straightforward. After an estimate of the gradient of the dose ratio with respect to the nuclide densities in the beam tube-<span class="hlt">filter</span> geometry is obtained, changes in the nuclide densities are made based on: (1) the magnitude and sign of the components of the dose ratio gradient, (2) the magnitude of the nuclide densities, (3) the upper and lower bound of each nuclide density, and (4) the linear constraint that the sum of the nuclide density fractions in each material zone be less than or equal to 1.0. A local <span class="hlt">optimal</span> solution is assumed to be found when one of the following conditions is satisfied in every material zone: (1) the maximum positive component of the gradient corresponds to a nuclide at its maximum density and the sum of the density fractions equals 1.0 or, and (2) the positive and negative components of the gradient correspond to nuclides densities at their upper and lower bounds, respectively, and the remaining components of the gradient are sufficiently small. The <span class="hlt">optimization</span> procedure has been applied to a beam tube-<span class="hlt">filter</span> geometry coupled to a simple tumor-patient head model and an improvement of 50% in the dose ratio was obtained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JKPS...64.1308K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JKPS...64.1308K"><span id="translatedtitle">Ridge <span class="hlt">filter</span> design for a <span class="hlt">particle</span> therapy line</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Chang Hyeuk; Han, Garam; Lee, Hwa-Ryun; Kim, Hyunyong; Jang, Hong Suk; Kim, Jeong Hwan; Park, Dong Wook; Jang, Sea Duk; Hwang, Won Taek; Kim, Geun-Beom; Yang, Tae-Keun</p> <p>2014-05-01</p> <p>The beam irradiation system for <span class="hlt">particle</span> therapy can use a passive or an active beam irradiation method. In the case of an active beam irradiation, using a ridge <span class="hlt">filter</span> would be appropriate to generate a spread-out Bragg peak (SOBP) through a large scanning area. For this study, a ridge <span class="hlt">filter</span> was designed as an energy modulation device for a prototype active scanning system at MC-50 in Korea Institute of Radiological And Medical Science (KIRAMS). The ridge <span class="hlt">filter</span> was designed to create a 10 mm of SOBP for a 45-MeV proton beam. To reduce the distal penumbra and the initial dose, [DM] determined the weighting factor for Bragg Peak by applying an in-house iteration code and the Minuit Fit package of Root. A single ridge bar shape and its corresponding thickness were obtained through 21 weighting factors. Also, a ridge <span class="hlt">filter</span> was fabricated to cover a large scanning area (300 × 300 mm2) by Polymethyl Methacrylate (PMMA). The fabricated ridge <span class="hlt">filter</span> was tested at the prototype active beamline of MC-50. The SOBP and the incident beam distribution were obtained by using HD-810 GaF chromatic film placed at a right triangle to the PMMA block. The depth dose profile for the SOBP can be obtained precisely by using the flat field correction and measuring the 2-dimensional distribution of the incoming beam. After the flat field correction is used, the experimental results show that the SOBP region matches with design requirement well, with 0.62% uniformity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1711125M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1711125M"><span id="translatedtitle">Improving the LPJ-GUESS modelled carbon balance with a <span class="hlt">particle</span> <span class="hlt">filter</span> data assimilation technique</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McRobert, Andrew; Scholze, Marko; Kemp, Sarah; Smith, Ben</p> <p>2015-04-01</p> <p>The recent increases in anthropogenic carbon dioxide (CO_2) emissions have disrupted the equilibrium in the global carbon cycle pools with the ocean and terrestrial pools increasing their respective storages to accommodate roughly half of the anthropogenic increase. Dynamic global vegetation models (DGVM) have been developed to quantify the modern carbon cycle changes. In this study, a <span class="hlt">particle</span> <span class="hlt">filter</span> data assimilation technique has been used to calibrate the process parameters in the DGVM LPJ-GUESS (Lund-Potsdam-Jena General Ecosystem Simulator). LPJ-GUESS simulates individual plant function types (pft) as a competitive balance within high resolution forest patches. Thirty process parameters have been <span class="hlt">optimized</span> twice, using both a sequential and iterative method of <span class="hlt">particle</span> <span class="hlt">filter</span>. The iterative method runs the model for the full time period of thirteen years and then evaluates the cost function from the mismatch of observations and model results before adjusting the parameters and repeating the full time period. The sequential method runs the model and <span class="hlt">particle</span> <span class="hlt">filter</span> for each year of the time series in order, adjusting the parameters between each year, then loops back to beginning of the series to repeat. For each <span class="hlt">particle</span>, the model output of NEP (Net Ecosystem Productivity) is compared to eddy flux measurements from ICOS flux towers to minimize the cost function. A high-resolution regional carbon balance has been simulated for central Sweden using a network of several ICOS flux towers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9248E..0JB','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9248E..0JB"><span id="translatedtitle">Independent motion detection with a rival penalized adaptive <span class="hlt">particle</span> <span class="hlt">filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Becker, Stefan; Hübner, Wolfgang; Arens, Michael</p> <p>2014-10-01</p> <p>Aggregation of pixel based motion detection into regions of interest, which include views of single moving objects in a scene is an essential pre-processing step in many vision systems. Motion events of this type provide significant information about the object type or build the basis for action recognition. Further, motion is an essential saliency measure, which is able to effectively support high level image analysis. When applied to static cameras, background subtraction methods achieve good results. On the other hand, motion aggregation on freely moving cameras is still a widely unsolved problem. The image flow, measured on a freely moving camera is the result from two major motion types. First the ego-motion of the camera and second object motion, that is independent from the camera motion. When capturing a scene with a camera these two motion types are adverse blended together. In this paper, we propose an approach to detect multiple moving objects from a mobile monocular camera system in an outdoor environment. The overall processing pipeline consists of a fast ego-motion compensation algorithm in the preprocessing stage. Real-time performance is achieved by using a sparse optical flow algorithm as an initial processing stage and a densely applied probabilistic <span class="hlt">filter</span> in the post-processing stage. Thereby, we follow the idea proposed by Jung and Sukhatme. Normalized intensity differences originating from a sequence of ego-motion compensated difference images represent the probability of moving objects. Noise and registration artefacts are <span class="hlt">filtered</span> out, using a Bayesian formulation. The resulting a posteriori distribution is located on image regions, showing strong amplitudes in the difference image which are in accordance with the motion prediction. In order to effectively estimate the a posteriori distribution, a <span class="hlt">particle</span> <span class="hlt">filter</span> is used. In addition to the fast ego-motion compensation, the main contribution of this paper is the design of the probabilistic <span class="hlt">filter</span> for real-time detection and tracking of independently moving objects. The proposed approach introduces a competition scheme between <span class="hlt">particles</span> in order to ensure an improved multi-modality. Further, the <span class="hlt">filter</span> design helps to generate a <span class="hlt">particle</span> distribution which is homogenous even in the presence of multiple targets showing non-rigid motion patterns. The effectiveness of the method is shown on exemplary outdoor sequences.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008SPIE.7109E..0LN','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008SPIE.7109E..0LN"><span id="translatedtitle">Scale-invariant visual tracking by <span class="hlt">particle</span> <span class="hlt">filtering</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakhmani, Arie; Tannenbaum, Allen</p> <p>2008-10-01</p> <p>Visual tracking is an important task that has received a lot of attention in recent years. Robust generic tracking tools are of major interest for applications ranging from surveillance and security to image guided surgery. In these applications, the objects of interest may be translated and scaled. We present here an algorithm that uses scaled normalized cross-correlation matching as the likelihood within the <span class="hlt">particle</span> <span class="hlt">filtering</span> framework. We do not need color and contour cues in our algorithm. Experimental results with constant rectangular templates show that the method is reliable for noisy and cluttered scenarios, and provides accurate and smooth trajectories in cases of target translation and scaling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012TSICE..47..310M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012TSICE..47..310M"><span id="translatedtitle">Identification of Backlash Type Hysteretic Systems Based on <span class="hlt">Particle</span> <span class="hlt">Filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Masuda, Tetsuya; Sugie, Toshiharu</p> <p></p> <p>This paper considers the system identification problem for hysteresis systems. This problem plays an important role in achieving better control performance, because many actuators have hysteresis property. This paper proposes a method to identify linear dynamical systems having input hysteresis property of backlash type. The method is based on <span class="hlt">particle</span> <span class="hlt">filter</span>, which is known for its applicability to a wide class of nonlinear systems. Numerical examples are given to demonstrate the effectiveness of the proposed method in detail. Furthermore, experimental validation is performed for a DC servo motor system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19272923','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19272923"><span id="translatedtitle">Resolving superimposed MUAPs using <span class="hlt">particle</span> swarm <span class="hlt">optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Marateb, Hamid Reza; McGill, Kevin C</p> <p>2009-03-01</p> <p>This paper presents an algorithm to resolve superimposed action potentials encountered during the decomposition of electromyographic signals. The algorithm uses <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> with a variety of features including randomization, crossover, and multiple swarms. In a simulation study involving realistic superpositions of two to five motor-unit action potentials, the algorithm had an accuracy of 98%. PMID:19272923</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011MeScT..22l5108W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011MeScT..22l5108W"><span id="translatedtitle">Fastening tool tracking system using a Kalman <span class="hlt">filter</span> and <span class="hlt">particle</span> <span class="hlt">filter</span> combination</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Won, Seong-hoon Peter; Melek, William; Golnaraghi, Farid</p> <p>2011-12-01</p> <p>This paper presents a position tracking system which estimates the position of the tip of a fastening tool. The proposed system uses a Kalman <span class="hlt">filter</span> (KF) and <span class="hlt">particle</span> <span class="hlt">filter</span> (PF) combination to synthesize measurements from an inertial measurement unit (IMU) and a position sensor. The KF part is used to estimate the position of the centre of mass of the tool, and the PF is used to estimate the orientation of the tool. In addition, a rule-based logic system is used to reduce angular velocity measurement error and identify the fastening action of the tool. The proposed system was validated experimentally using various scenarios representative of assembly tasks in a factory environment. The experiment results show that the proposed system can accurately identify the fastened bolt even when the angular velocity measurement is not accurate provided that a large enough number of <span class="hlt">particles</span> is used. In addition, even when there are multiple possibilities for fastened bolt positions, the experimental results show that the proposed system can correctly identify the fastened bolt by utilizing the accumulated position error of each <span class="hlt">particle</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9092E..0AM','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9092E..0AM"><span id="translatedtitle">Tracking low SNR targets using <span class="hlt">particle</span> <span class="hlt">filter</span> with flow control</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moshtagh, Nima; Romberg, Paul M.; Chan, Moses W.</p> <p>2014-06-01</p> <p>In this work we study the problem of detecting and tracking challenging targets that exhibit low signal-to-noise ratios (SNR). We have developed a <span class="hlt">particle</span> <span class="hlt">filter</span>-based track-before-detect (TBD) algorithm for tracking such dim targets. The approach incorporates the most recent state estimates to control the <span class="hlt">particle</span> flow accounting for target dynamics. The flow control enables accumulation of signal information over time to compensate for target motion. The performance of this approach is evaluated using a sensitivity analysis based on varying target speed and SNR values. This analysis was conducted using high-fidelity sensor and target modeling in realistic scenarios. Our results show that the proposed TBD algorithm is capable of tracking targets in cluttered images with SNR values much less than one.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23742356','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23742356"><span id="translatedtitle">Bayesian approach of nearfield acoustic reconstruction with <span class="hlt">particle</span> <span class="hlt">filters</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bai, Mingsian R; Agarwal, Amal; Chen, Ching-Cheng; Wang, Yen-Chih</p> <p>2013-06-01</p> <p>This paper demonstrates that inverse source reconstruction can be performed using a methodology of <span class="hlt">particle</span> <span class="hlt">filters</span> that relies primarily on the Bayesian approach of parameter estimation. In particular, the proposed approach is applied in the context of nearfield acoustic holography based on the equivalent source method (ESM). A state-space model is formulated in light of the ESM. The parameters to estimate are amplitudes and locations of the equivalent sources. The parameters constitute the state vector which follows a first-order Markov process with the transition matrix being the identity for every frequency-domain data frame. <span class="hlt">Filtered</span> estimates of the state vector obtained are assigned weights adaptively. The implementation of recursive Bayesian <span class="hlt">filters</span> involves a sequential Monte Carlo sampling procedure that treats the estimates as point masses with a discrete probability mass function (PMF) which evolves with iteration. The weight update equation governs the evolution of this PMF and depends primarily on the likelihood function and the prior distribution. It is evident from the simulation results that the inclusion of the appropriate prior distribution is crucial in the parameter estimation. PMID:23742356</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AtmEn..40.4797Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AtmEn..40.4797Y"><span id="translatedtitle">Loss of fine <span class="hlt">particle</span> ammonium from denuded nylon <span class="hlt">filters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, Xiao-Ying; Lee, Taehyoung; Ayres, Benjamin; Kreidenweis, Sonia M.; Malm, William; Collett, Jeffrey L.</p> <p></p> <p>Ammonium is an important constituent of fine particulate mass in the atmosphere, but can be difficult to quantify due to possible sampling artifacts. Losses of semivolatile species such as NH 4NO 3 can be particularly problematic. In order to evaluate ammonium losses from aerosol <span class="hlt">particles</span> collected on <span class="hlt">filters</span>, a series of field experiments was conducted using denuded nylon and Teflon <span class="hlt">filters</span> at Bondville, IL (February 2003), San Gorgonio, CA (April 2003 and July 2004), Grand Canyon NP, AZ (May, 2003), Brigantine, NJ (November 2003), and Great Smoky Mountains National Park (NP), TN (July-August 2004). Samples were collected over 24 h periods. Losses from denuded nylon <span class="hlt">filters</span> ranged from 10% (monthly average) in Bondville, IL to 28% in San Gorgonio, CA in summer. Losses on individual sample days ranged from 1% to 65%. Losses tended to increase with increasing diurnal temperature and relative humidity changes and with the fraction of ambient total N(-III) (particulate NH 4++gaseous NH 3) present as gaseous NH 3. The amount of ammonium lost at most sites could be explained by the amount of NH 4NO 3 present in the sampled aerosol. Ammonium losses at Great Smoky Mountains NP, however, significantly exceeded the amount of NH 4NO 3 collected. Ammoniated organic salts are suggested as additional important contributors to observed ammonium loss at this location.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/909252','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/909252"><span id="translatedtitle">Loss of Fine <span class="hlt">Particle</span> Ammonium from Denuded Nylon <span class="hlt">Filters</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yu, Xiao-Ying; Lee, Taehyoung; Ayres, Benjamin; Kreidenweis, Sonia M.; Malm, William C.; Collett, Jeffrey L.</p> <p>2006-08-01</p> <p>Ammonium is an important constituent of fine particulate mass in the atmosphere, but can be difficult to quantify due to possible sampling artifacts. Losses of semivolatile species such as NH4NO3 can be particularly problematic. In order to evaluate ammonium losses from aerosol <span class="hlt">particles</span> collected on <span class="hlt">filters</span>, a series of field experiments was conducted using denuded nylon and Teflon <span class="hlt">filters</span> at Bondville, Illinois (February 2003), San Gorgonio, California (April 2003 and July 2004), Grand Canyon National Park, Arizona (May, 2003), Brigantine, New Jersey (November 2003), and Great Smoky Mountains National Park (NP), Tennessee (July–August 2004). Samples were collected over 24-hr periods. Losses from denuded nylon <span class="hlt">filters</span> ranged from 10% (monthly average) in Bondville, Illinois to 28% in San Gorgonio, California in summer. Losses on individual sample days ranged from 1% to 65%. Losses tended to increase with increasing diurnal temperature and relative humidity changes and with the fraction of ambient total N(--III) (particulate NH4+ plus gaseous NH3) present as gaseous NH3. The amount of ammonium lost at most sites could be explained by the amount of NH4NO3 present in the sampled aerosol. Ammonium losses at Great Smoky Mountains NP, however, significantly exceeded the amount of NH4NO3 collected. Ammoniated organic salts are suggested as additional important contributors to observed ammonium loss at this location.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EJASP2002...28Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EJASP2002...28Z"><span id="translatedtitle">Joint Audio-Visual Tracking Using <span class="hlt">Particle</span> <span class="hlt">Filters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zotkin, Dmitry N.; Duraiswami, Ramani; Davis, Larry S.</p> <p>2002-12-01</p> <p>It is often advantageous to track objects in a scene using multimodal information when such information is available. We use audio as a complementary modality to video data, which, in comparison to vision, can provide faster localization over a wider field of view. We present a <span class="hlt">particle-filter</span> based tracking framework for performing multimodal sensor fusion for tracking people in a videoconferencing environment using multiple cameras and multiple microphone arrays. One advantage of our proposed tracker is its ability to seamlessly handle temporary absence of some measurements (e.g., camera occlusion or silence). Another advantage is the possibility of self-calibration of the joint system to compensate for imprecision in the knowledge of array or camera parameters by treating them as containing an unknown statistical component that can be determined using the <span class="hlt">particle</span> <span class="hlt">filter</span> framework during tracking. We implement the algorithm in the context of a videoconferencing and meeting recording system. The system also performs high-level semantic analysis of the scene by keeping participant tracks, recognizing turn-taking events and recording an annotated transcript of the meeting. Experimental results are presented. Our system operates in real-time and is shown to be robust and reliable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4052086','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4052086"><span id="translatedtitle">Nonlinear EEG Decoding Based on a <span class="hlt">Particle</span> <span class="hlt">Filter</span> Model</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hong, Jun</p> <p>2014-01-01</p> <p>While the world is stepping into the aging society, rehabilitation robots play a more and more important role in terms of both rehabilitation treatment and nursing of the patients with neurological diseases. Benefiting from the abundant contents of movement information, electroencephalography (EEG) has become a promising information source for rehabilitation robots control. Although the multiple linear regression model was used as the decoding model of EEG signals in some researches, it has been considered that it cannot reflect the nonlinear components of EEG signals. In order to overcome this shortcoming, we propose a nonlinear decoding model, the <span class="hlt">particle</span> <span class="hlt">filter</span> model. Two- and three-dimensional decoding experiments were performed to test the validity of this model. In decoding accuracy, the results are comparable to those of the multiple linear regression model and previous EEG studies. In addition, the <span class="hlt">particle</span> <span class="hlt">filter</span> model uses less training data and more frequency information than the multiple linear regression model, which shows the potential of nonlinear decoding models. Overall, the findings hold promise for the furtherance of EEG-based rehabilitation robots. PMID:24949420</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27123982','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27123982"><span id="translatedtitle">Lagrange Interpolation Learning <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kai, Zhang; Jinchun, Song; Ke, Ni; Song, Li</p> <p>2016-01-01</p> <p>In recent years, comprehensive learning <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (CLPSO) has attracted the attention of many scholars for using in solving multimodal problems, as it is excellent in preserving the <span class="hlt">particles</span>' diversity and thus preventing premature convergence. However, CLPSO exhibits low solution accuracy. Aiming to address this issue, we proposed a novel algorithm called LILPSO. First, this algorithm introduced a Lagrange interpolation method to perform a local search for the global best point (gbest). Second, to gain a better exemplar, one gbest, another two <span class="hlt">particle</span>'s historical best points (pbest) are chosen to perform Lagrange interpolation, then to gain a new exemplar, which replaces the CLPSO's comparison method. The numerical experiments conducted on various functions demonstrate the superiority of this algorithm, and the two methods are proven to be efficient for accelerating the convergence without leading the <span class="hlt">particle</span> to premature convergence. PMID:27123982</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24344695','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24344695"><span id="translatedtitle">Multi-strategy coevolving aging <span class="hlt">particle</span> <span class="hlt">optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Iacca, Giovanni; Caraffini, Fabio; Neri, Ferrante</p> <p>2014-02-01</p> <p>We propose Multi-Strategy Coevolving Aging <span class="hlt">Particles</span> (MS-CAP), a novel population-based algorithm for black-box <span class="hlt">optimization</span>. In a memetic fashion, MS-CAP combines two components with complementary algorithm logics. In the first stage, each <span class="hlt">particle</span> is perturbed independently along each dimension with a progressively shrinking (decaying) radius, and attracted towards the current best solution with an increasing force. In the second phase, the <span class="hlt">particles</span> are mutated and recombined according to a multi-strategy approach in the fashion of the ensemble of mutation strategies in Differential Evolution. The proposed algorithm is tested, at different dimensionalities, on two complete black-box <span class="hlt">optimization</span> benchmarks proposed at the Congress on Evolutionary Computation 2010 and 2013. To demonstrate the applicability of the approach, we also test MS-CAP to train a Feedforward Neural Network modeling the kinematics of an 8-link robot manipulator. The numerical results show that MS-CAP, for the setting considered in this study, tends to outperform the state-of-the-art <span class="hlt">optimization</span> algorithms on a large set of problems, thus resulting in a robust and versatile <span class="hlt">optimizer</span>. PMID:24344695</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011SPIE.8193E..2IS','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011SPIE.8193E..2IS"><span id="translatedtitle">The new approach for infrared target tracking based on the <span class="hlt">particle</span> <span class="hlt">filter</span> algorithm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Hang; Han, Hong-xia</p> <p>2011-08-01</p> <p>Target tracking on the complex background in the infrared image sequence is hot research field. It provides the important basis in some fields such as video monitoring, precision, and video compression human-computer interaction. As a typical algorithms in the target tracking framework based on <span class="hlt">filtering</span> and data connection, the <span class="hlt">particle</span> <span class="hlt">filter</span> with non-parameter estimation characteristic have ability to deal with nonlinear and non-Gaussian problems so it were widely used. There are various forms of density in the <span class="hlt">particle</span> <span class="hlt">filter</span> algorithm to make it valid when target occlusion occurred or recover tracking back from failure in track procedure, but in order to capture the change of the state space, it need a certain amount of <span class="hlt">particles</span> to ensure samples is enough, and this number will increase in accompany with dimension and increase exponentially, this led to the increased amount of calculation is presented. In this paper <span class="hlt">particle</span> <span class="hlt">filter</span> algorithm and the Mean shift will be combined. Aiming at deficiencies of the classic mean shift Tracking algorithm easily trapped into local minima and Unable to get global <span class="hlt">optimal</span> under the complex background. From these two perspectives that "adaptive multiple information fusion" and "with <span class="hlt">particle</span> <span class="hlt">filter</span> framework combining", we expand the classic Mean Shift tracking framework .Based on the previous perspective, we proposed an improved Mean Shift infrared target tracking algorithm based on multiple information fusion. In the analysis of the infrared characteristics of target basis, Algorithm firstly extracted target gray and edge character and Proposed to guide the above two characteristics by the moving of the target information thus we can get new sports guide grayscale characteristics and motion guide border feature. Then proposes a new adaptive fusion mechanism, used these two new information adaptive to integrate into the Mean Shift tracking framework. Finally we designed a kind of automatic target model updating strategy to further improve tracking performance. Experimental results show that this algorithm can compensate shortcoming of the <span class="hlt">particle</span> <span class="hlt">filter</span> has too much computation, and can effectively overcome the fault that mean shift is easy to fall into local extreme value instead of global maximum value .Last because of the gray and fusion target motion information, this approach also inhibit interference from the background, ultimately improve the stability and the real-time of the target track.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011EJASP2011...53C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011EJASP2011...53C"><span id="translatedtitle">Multi-prediction <span class="hlt">particle</span> <span class="hlt">filter</span> for efficient parallelized implementation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chu, Chun-Yuan; Chao, Chih-Hao; Chao, Min-An; Wu, An-Yeu Andy</p> <p>2011-12-01</p> <p><span class="hlt">Particle</span> <span class="hlt">filter</span> (PF) is an emerging signal processing methodology, which can effectively deal with nonlinear and non-Gaussian signals by a sample-based approximation of the state probability density function. The <span class="hlt">particle</span> generation of the PF is a data-independent procedure and can be implemented in parallel. However, the resampling procedure in the PF is a sequential task in natural and difficult to be parallelized. Based on the Amdahl's law, the sequential portion of a task limits the maximum speed-up of the parallelized implementation. Moreover, large <span class="hlt">particle</span> number is usually required to obtain an accurate estimation, and the complexity of the resampling procedure is highly related to the number of <span class="hlt">particles</span>. In this article, we propose a multi-prediction (MP) framework with two selection approaches. The proposed MP framework can reduce the required <span class="hlt">particle</span> number for target estimation accuracy, and the sequential operation of the resampling can be reduced. Besides, the overhead of the MP framework can be easily compensated by parallel implementation. The proposed MP-PF alleviates the global sequential operation by increasing the local parallel computation. In addition, the MP-PF is very suitable for multi-core graphics processing unit (GPU) platform, which is a popular parallel processing architecture. We give prototypical implementations of the MP-PFs on multi-core GPU platform. For the classic bearing-only tracking experiments, the proposed MP-PF can be 25.1 and 15.3 times faster than the sequential importance resampling-PF with 10,000 and 20,000 <span class="hlt">particles</span>, respectively. Hence, the proposed MP-PF can enhance the efficiency of the parallelization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18602332','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18602332"><span id="translatedtitle">Probabilistic white matter fiber tracking using <span class="hlt">particle</span> <span class="hlt">filtering</span> and von Mises-Fisher sampling.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Fan; Hancock, Edwin R; Goodlett, Casey; Gerig, Guido</p> <p>2009-02-01</p> <p>Standard <span class="hlt">particle</span> <span class="hlt">filtering</span> technique have previously been applied to the problem of fiber tracking by Brun et al. [Brun, A., Bjornemo, M., Kikinis, R., Westin, C.F., 2002. White matter tractography using sequential importance sampling. In: Proceedings of the ISMRM Annual Meeting, p. 1131] and Bjornemo et al. [Bjornemo, M., Brun, A., Kikinis, R., Westin, C.F., 2002. Regularized stochastic white matter tractography using diffusion tensor MRI, In: Proc. MICCAI, pp. 435-442]. However, these previous attempts have not utilised the full power of the technique, and as a result the fiber paths were tracked in a goal directed way. In this paper, we provide an advanced technique by presenting a fast and novel probabilistic method for white matter fiber tracking in diffusion weighted MRI (DWI), which takes advantage of the weighting and resampling mechanism of <span class="hlt">particle</span> <span class="hlt">filtering</span>. We formulate fiber tracking using a non-linear state space model which captures both smoothness regularity of the fibers and the uncertainties in the local fiber orientations due to noise and partial volume effects. Global fiber tracking is then posed as a problem of <span class="hlt">particle</span> <span class="hlt">filtering</span>. To model the posterior distribution, we classify voxels of the white matter as either prolate or oblate tensors. We then construct the orientation distributions for prolate and oblate tensors separately. Finally, the importance density function for <span class="hlt">particle</span> <span class="hlt">filtering</span> is modeled using the von Mises-Fisher distribution on a unit sphere. Fast and efficient sampling is achieved using Ulrich-Wood's simulation algorithm. Given a seed point, the method is able to rapidly locate the globally <span class="hlt">optimal</span> fiber and also provides a probability map for potential connections. The proposed method is validated and compared to alternative methods both on synthetic data and real-world brain MRI datasets. PMID:18602332</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AIPC.1207..912L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AIPC.1207..912L"><span id="translatedtitle">Numerical analysis of <span class="hlt">particle</span> distribution on multi-pipe ceramic candle <span class="hlt">filters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, H. X.; Gao, B. G.; Tie, Z. X.; Sun, Z. J.; Wang, F. H.</p> <p>2010-03-01</p> <p>The <span class="hlt">particle</span> distribution on the ceramic <span class="hlt">filter</span> surface has great effect on filtration performance. The numerical simulation method is used to analyze the <span class="hlt">particle</span> distribution near the <span class="hlt">filter</span> surface under different operation conditions. The gas/solid two-phase flow field in the ceramic <span class="hlt">filter</span> vessel was simulated using the Eulerian two-fluid model provided by FLUENT code. The user-defined function was loaded with the FLUTNT solver to define the interaction between the <span class="hlt">particle</span> and the gas near the porous ceramic candle <span class="hlt">filter</span>. The distribution of the <span class="hlt">filter</span> cake along the <span class="hlt">filter</span> length and around the <span class="hlt">filter</span> circumference was analyzed. The simulation results agree well with experimental data. The simulation model can be used to predict the <span class="hlt">particle</span> distribution and provide theory direction for the engineering application of porous ceramic <span class="hlt">filters</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27107737','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27107737"><span id="translatedtitle">Analysis of single <span class="hlt">particle</span> diffusion with transient binding using <span class="hlt">particle</span> <span class="hlt">filtering</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bernstein, Jason; Fricks, John</p> <p>2016-07-21</p> <p>Diffusion with transient binding occurs in a variety of biophysical processes, including movement of transmembrane proteins, T cell adhesion, and caging in colloidal fluids. We model diffusion with transient binding as a Brownian <span class="hlt">particle</span> undergoing Markovian switching between free diffusion when unbound and diffusion in a quadratic potential centered around a binding site when bound. Assuming the binding site is the last position of the <span class="hlt">particle</span> in the unbound state and Gaussian observational error obscures the true position of the <span class="hlt">particle</span>, we use <span class="hlt">particle</span> <span class="hlt">filtering</span> to predict when the <span class="hlt">particle</span> is bound and to locate the binding sites. Maximum likelihood estimators of diffusion coefficients, state transition probabilities, and the spring constant in the bound state are computed with a stochastic Expectation-Maximization (EM) algorithm. PMID:27107737</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008MSSP...22..233C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008MSSP...22..233C"><span id="translatedtitle">Design of a higher-order digital differentiator using a <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chang, Wei-Der; Chang, Dai-Ming</p> <p>2008-01-01</p> <p>This paper applies a novel <span class="hlt">optimization</span> algorithm, <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO), to design a higher-order differentiator that contains two different structures of even and odd orders. Four cases of linear phase finite impulse response (FIR) <span class="hlt">filters</span> are designed to match the prescribed differentiation frequency response by using PSO algorithm. The algorithm with real-valued manipulations uses the velocity updating and position updating formulas to <span class="hlt">optimally</span> solve the impulse response of the <span class="hlt">filter</span> to the digital differentiator design problem. Simulation results reveals that the proposed method provides much better design performance than the well-known McClellan-Parks method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011SPIE.8050E..0XD','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011SPIE.8050E..0XD"><span id="translatedtitle">Hollywood log-homotopy: movies of <span class="hlt">particle</span> flow for nonlinear <span class="hlt">filters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Daum, Fred; Huang, Jim</p> <p>2011-06-01</p> <p>In this paper we show five movies of <span class="hlt">particle</span> flow to provide insight and intuition about this new algorithm. The <span class="hlt">particles</span> flow solves the well known and important problem of <span class="hlt">particle</span> degeneracy. Bayes' rule is implemented by <span class="hlt">particle</span> flow rather than as a pointwise multiplication. This theory is roughly seven orders of magnitude faster than standard <span class="hlt">particle</span> <span class="hlt">filters</span>, and it often beats the extended Kalman <span class="hlt">filter</span> by two orders of magnitude in accuracy for difficult nonlinear problems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8768E..1AZ','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8768E..1AZ"><span id="translatedtitle">Adaptive mean shift and <span class="hlt">particle</span> <span class="hlt">filter</span> tracking method based on joint feature</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, La; Yang, Yingyun; Wang, Huabing; Yang, Yansi; Liu, Bo</p> <p>2013-03-01</p> <p>In the object tracking area, both <span class="hlt">particle</span> <span class="hlt">filter</span> and mean shift algorithm have proven successful approaches. However, both of them have notable weakness. In this paper, we present a new algorithm which combined the two algorithms to track the target. First, the mean shift algorithm is employed to search an object candidate near the target state. Then, if the candidate is good enough, it will be used to adapt the <span class="hlt">particle</span> <span class="hlt">filter</span> parameters, including the number of <span class="hlt">particle</span> <span class="hlt">filter</span>, and etc. Finally, the <span class="hlt">particle</span> <span class="hlt">filter</span> will estimate the target state based on these new parameters. Further, the paper introduces the color-texture combined feature instead of color feature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.G33B0985D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.G33B0985D"><span id="translatedtitle"><span class="hlt">Optimal</span> <span class="hlt">Filtering</span> in Mass Transport Modeling From Satellite Gravimetry Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ditmar, P.; Hashemi Farahani, H.; Klees, R.</p> <p>2011-12-01</p> <p>Monitoring natural mass transport in the Earth's system, which has marked a new era in Earth observation, is largely based on the data collected by the GRACE satellite mission. Unfortunately, this mission is not free from certain limitations, two of which are especially critical. Firstly, its sensitivity is strongly anisotropic: it senses the north-south component of the mass re-distribution gradient much better than the east-west component. Secondly, it suffers from a trade-off between temporal and spatial resolution: a high (e.g., daily) temporal resolution is only possible if the spatial resolution is sacrificed. To make things even worse, the GRACE satellites enter occasionally a phase when their orbit is characterized by a short repeat period, which makes it impossible to reach a high spatial resolution at all. A way to mitigate limitations of GRACE measurements is to design <span class="hlt">optimal</span> data processing procedures, so that all available information is fully exploited when modeling mass transport. This implies, in particular, that an unconstrained model directly derived from satellite gravimetry data needs to be <span class="hlt">optimally</span> <span class="hlt">filtered</span>. In principle, this can be realized with a Wiener <span class="hlt">filter</span>, which is built on the basis of covariance matrices of noise and signal. In practice, however, a compilation of both matrices (and, therefore, of the <span class="hlt">filter</span> itself) is not a trivial task. To build the covariance matrix of noise in a mass transport model, it is necessary to start from a realistic model of noise in the level-1B data. Furthermore, a routine satellite gravimetry data processing includes, in particular, the subtraction of nuisance signals (for instance, associated with atmosphere and ocean), for which appropriate background models are used. Such models are not error-free, which has to be taken into account when the noise covariance matrix is constructed. In addition, both signal and noise covariance matrices depend on the type of mass transport processes under investigation. For instance, processes of hydrological origin occur at short time scales, so that the input time series is typically short (1 month or less), which implies a relatively strong noise in the derived model. On the contrary, study of a long-term ice mass depletion requires a long time series of satellite data, which leads to a reduction of noise in the mass transport model. Of course, the spatial pattern (and therefore, the signal covariance matrices) of various mass transport processes are also very different. In the presented study, we compare various strategies to build the signal and noise covariance matrices in the context of mass transport modeling. In this way, we demonstrate the benefits of an accurate construction of an <span class="hlt">optimal</span> <span class="hlt">filter</span> as outlined above, compared to simplified strategies. Furthermore, we consider both models based on GRACE data alone and combined GRACE/GOCE models. In this way, we shed more light on a potential synergy of the GRACE and GOCE satellite mission. This is important nor only for the best possible mass transport modeling on the basis of all available data, but also for the <span class="hlt">optimal</span> planning of future satellite gravity missions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4707022','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4707022"><span id="translatedtitle"><span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> with Double Learning Patterns</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Shen, Yuanxia; Wei, Linna; Zeng, Chuanhua; Chen, Jian</p> <p>2016-01-01</p> <p><span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) is an effective tool in solving <span class="hlt">optimization</span> problems. However, PSO usually suffers from the premature convergence due to the quick losing of the swarm diversity. In this paper, we first analyze the motion behavior of the swarm based on the probability characteristic of learning parameters. Then a PSO with double learning patterns (PSO-DLP) is developed, which employs the master swarm and the slave swarm with different learning patterns to achieve a trade-off between the convergence speed and the swarm diversity. The <span class="hlt">particles</span> in the master swarm and the slave swarm are encouraged to explore search for keeping the swarm diversity and to learn from the global best <span class="hlt">particle</span> for refining a promising solution, respectively. When the evolutionary states of two swarms interact, an interaction mechanism is enabled. This mechanism can help the slave swarm in jumping out of the local optima and improve the convergence precision of the master swarm. The proposed PSO-DLP is evaluated on 20 benchmark functions, including rotated multimodal and complex shifted problems. The simulation results and statistical analysis show that PSO-DLP obtains a promising performance and outperforms eight PSO variants. PMID:26858747</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4849747','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4849747"><span id="translatedtitle">Lagrange Interpolation Learning <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2016-01-01</p> <p>In recent years, comprehensive learning <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (CLPSO) has attracted the attention of many scholars for using in solving multimodal problems, as it is excellent in preserving the particles’ diversity and thus preventing premature convergence. However, CLPSO exhibits low solution accuracy. Aiming to address this issue, we proposed a novel algorithm called LILPSO. First, this algorithm introduced a Lagrange interpolation method to perform a local search for the global best point (gbest). Second, to gain a better exemplar, one gbest, another two particle’s historical best points (pbest) are chosen to perform Lagrange interpolation, then to gain a new exemplar, which replaces the CLPSO’s comparison method. The numerical experiments conducted on various functions demonstrate the superiority of this algorithm, and the two methods are proven to be efficient for accelerating the convergence without leading the <span class="hlt">particle</span> to premature convergence. PMID:27123982</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/952810','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/952810"><span id="translatedtitle">Using triaxial magnetic fields to create <span class="hlt">optimal</span> <span class="hlt">particle</span> composites.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Martin, James Ellis</p> <p>2004-05-01</p> <p>The properties of a <span class="hlt">particle</span> composite can be controlled by organizing the <span class="hlt">particles</span> into assemblies. The properties of the composite will depend on the structure of the <span class="hlt">particle</span> assemblies, and for any give property there is some <span class="hlt">optimal</span> structure. Through simulation and experiment we show that the application of heterodyned triaxial magnetic or electric fields generates structures that <span class="hlt">optimize</span> the magnetic and dielectric properties of <span class="hlt">particle</span> composites. We suggest that <span class="hlt">optimizing</span> these properties <span class="hlt">optimizes</span> other properties, such as transport properties, and we give as one example of this <span class="hlt">optimization</span> the magnetostriction of magnetic <span class="hlt">particle</span> composites formed in a silicone elastomer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4030565','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4030565"><span id="translatedtitle">Human Behavior-Based <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Xu, Gang; Ding, Gui-yan; Sun, Yu-bo</p> <p>2014-01-01</p> <p><span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> (PSO) has attracted many researchers interested in dealing with various <span class="hlt">optimization</span> problems, owing to its easy implementation, few tuned parameters, and acceptable performance. However, the algorithm is easy to trap in the local optima because of rapid losing of the population diversity. Therefore, improving the performance of PSO and decreasing the dependence on parameters are two important research hot points. In this paper, we present a human behavior-based PSO, which is called HPSO. There are two remarkable differences between PSO and HPSO. First, the global worst <span class="hlt">particle</span> was introduced into the velocity equation of PSO, which is endowed with random weight which obeys the standard normal distribution; this strategy is conducive to trade off exploration and exploitation ability of PSO. Second, we eliminate the two acceleration coefficients c1 and c2 in the standard PSO (SPSO) to reduce the parameters sensitivity of solved problems. Experimental results on 28 benchmark functions, which consist of unimodal, multimodal, rotated, and shifted high-dimensional functions, demonstrate the high performance of the proposed algorithm in terms of convergence accuracy and speed with lower computation cost. PMID:24883357</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24883357','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24883357"><span id="translatedtitle">Human behavior-based <span class="hlt">particle</span> swarm <span class="hlt">optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Hao; Xu, Gang; Ding, Gui-Yan; Sun, Yu-Bo</p> <p>2014-01-01</p> <p><span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> (PSO) has attracted many researchers interested in dealing with various <span class="hlt">optimization</span> problems, owing to its easy implementation, few tuned parameters, and acceptable performance. However, the algorithm is easy to trap in the local optima because of rapid losing of the population diversity. Therefore, improving the performance of PSO and decreasing the dependence on parameters are two important research hot points. In this paper, we present a human behavior-based PSO, which is called HPSO. There are two remarkable differences between PSO and HPSO. First, the global worst <span class="hlt">particle</span> was introduced into the velocity equation of PSO, which is endowed with random weight which obeys the standard normal distribution; this strategy is conducive to trade off exploration and exploitation ability of PSO. Second, we eliminate the two acceleration coefficients c 1 and c 2 in the standard PSO (SPSO) to reduce the parameters sensitivity of solved problems. Experimental results on 28 benchmark functions, which consist of unimodal, multimodal, rotated, and shifted high-dimensional functions, demonstrate the high performance of the proposed algorithm in terms of convergence accuracy and speed with lower computation cost. PMID:24883357</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4415408','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4415408"><span id="translatedtitle">Simultaneous learning and <span class="hlt">filtering</span> without delusions: a Bayes-<span class="hlt">optimal</span> combination of Predictive Inference and Adaptive <span class="hlt">Filtering</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kneissler, Jan; Drugowitsch, Jan; Friston, Karl; Butz, Martin V.</p> <p>2015-01-01</p> <p>Predictive coding appears to be one of the fundamental working principles of brain processing. Amongst other aspects, brains often predict the sensory consequences of their own actions. Predictive coding resembles Kalman <span class="hlt">filtering</span>, where incoming sensory information is <span class="hlt">filtered</span> to produce prediction errors for subsequent adaptation and learning. However, to generate prediction errors given motor commands, a suitable temporal forward model is required to generate predictions. While in engineering applications, it is usually assumed that this forward model is known, the brain has to learn it. When <span class="hlt">filtering</span> sensory input and learning from the residual signal in parallel, a fundamental problem arises: the system can enter a delusional loop when <span class="hlt">filtering</span> the sensory information using an overly trusted forward model. In this case, learning stalls before accurate convergence because uncertainty about the forward model is not properly accommodated. We present a Bayes-<span class="hlt">optimal</span> solution to this generic and pernicious problem for the case of linear forward models, which we call Predictive Inference and Adaptive <span class="hlt">Filtering</span> (PIAF). PIAF <span class="hlt">filters</span> incoming sensory information and learns the forward model simultaneously. We show that PIAF is formally related to Kalman <span class="hlt">filtering</span> and to the Recursive Least Squares linear approximation method, but combines these procedures in a Bayes <span class="hlt">optimal</span> fashion. Numerical evaluations confirm that the delusional loop is precluded and that the learning of the forward model is more than 10-times faster when compared to a naive combination of Kalman <span class="hlt">filtering</span> and Recursive Least Squares. PMID:25983690</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005SPIE.5685..430B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005SPIE.5685..430B"><span id="translatedtitle"><span class="hlt">Particle</span> <span class="hlt">filtering</span> with multiple cues for object tracking in video sequences</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brasnett, Paul A.; Mihaylova, Lyudmila; Canagarajah, Nishan; Bull, David</p> <p>2005-03-01</p> <p>In this paper we investigate object tracking in video sequences by using the potential of <span class="hlt">particle</span> <span class="hlt">filtering</span> to process features from video frames. A <span class="hlt">particle</span> <span class="hlt">filter</span> (PF) and a Gaussian sum <span class="hlt">particle</span> <span class="hlt">filter</span> (GSPF) are developed based upon multiple information cues, namely colour and texture, which are described with highly nonlinear models. The algorithms rely on likelihood factorisation as a product of the likelihoods of the cues. We demonstrate the advantages of tracking with multiple independent complementary cues compared to tracking with individual cues. The advantages are increased robustness and improved accuracy. The performance of the two <span class="hlt">filters</span> is investigated and validated over both synthetic and natural video sequences.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1984isa..conf..577L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1984isa..conf..577L"><span id="translatedtitle">Design of <span class="hlt">optimal</span> Nyquist and partial response FIR digital <span class="hlt">filters</span> using linear programming techniques</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liang, J.-K.; Lu, F.-C.</p> <p></p> <p>The design of a Nyquist <span class="hlt">filter</span> for generating a band-limited pulse for data transmission zero intersymbol interference is formulated as a linear programming problem, and the Steinglitz (1979) program is modified and then used to design such pulse shaping <span class="hlt">filters</span>. Advantages of the new approach over other methods with regard to design speed and <span class="hlt">filter</span> <span class="hlt">optimality</span> are described and illustrated with examples.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016OptCo.358...59C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016OptCo.358...59C"><span id="translatedtitle"><span class="hlt">Optimal</span> design of multichannel fiber Bragg grating <span class="hlt">filters</span> using Pareto multi-objective <span class="hlt">optimization</span> algorithm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Jing; Liu, Tundong; Jiang, Hao</p> <p>2016-01-01</p> <p>A Pareto-based multi-objective <span class="hlt">optimization</span> approach is proposed to design multichannel FBG <span class="hlt">filters</span>. Instead of defining a single <span class="hlt">optimal</span> objective, the proposed method establishes the multi-objective model by taking two design objectives into account, which are minimizing the maximum index modulation and minimizing the mean dispersion error. To address this <span class="hlt">optimization</span> problem, we develop a two-stage evolutionary computation approach integrating an elitist non-dominated sorting genetic algorithm (NSGA-II) and technique for order preference by similarity to ideal solution (TOPSIS). NSGA-II is utilized to search for the candidate solutions in terms of both objectives. The obtained results are provided as Pareto front. Subsequently, the best compromise solution is determined by the TOPSIS method from the Pareto front according to the decision maker's preference. The design results show that the proposed approach yields a remarkable reduction of the maximum index modulation and the performance of dispersion spectra of the designed <span class="hlt">filter</span> can be <span class="hlt">optimized</span> simultaneously.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EJASP2015...83Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EJASP2015...83Z"><span id="translatedtitle">Effect of embedded unbiasedness on discrete-time <span class="hlt">optimal</span> FIR <span class="hlt">filtering</span> estimates</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Shunyi; Shmaliy, Yuriy S.; Liu, Fei; Ibarra-Manzano, Oscar; Khan, Sanowar H.</p> <p>2015-12-01</p> <p>Unbiased estimation is an efficient alternative to <span class="hlt">optimal</span> estimation when the noise statistics are not fully known and/or the model undergoes temporary uncertainties. In this paper, we investigate the effect of embedded unbiasedness (EU) on <span class="hlt">optimal</span> finite impulse response (OFIR) <span class="hlt">filtering</span> estimates of linear discrete time-invariant state-space models. A new OFIR-EU <span class="hlt">filter</span> is derived by minimizing the mean square error (MSE) subject to the unbiasedness constraint. We show that the OFIR-UE <span class="hlt">filter</span> is equivalent to the minimum variance unbiased FIR (UFIR) <span class="hlt">filter</span>. Unlike the OFIR <span class="hlt">filter</span>, the OFIR-EU <span class="hlt">filter</span> does not require the initial conditions. In terms of accuracy, the OFIR-EU <span class="hlt">filter</span> occupies an intermediate place between the UFIR and OFIR <span class="hlt">filters</span>. Contrary to the UFIR <span class="hlt">filter</span> which MSE is minimized by the <span class="hlt">optimal</span> horizon of N opt points, the MSEs in the OFIR-EU and OFIR <span class="hlt">filters</span> diminish with N and these <span class="hlt">filters</span> are thus full-horizon. Based upon several examples, we show that the OFIR-UE <span class="hlt">filter</span> has higher immunity against errors in the noise statistics and better robustness against temporary model uncertainties than the OFIR and Kalman <span class="hlt">filters</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25973723','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25973723"><span id="translatedtitle">Estimation of Tumor Size Evolution Using <span class="hlt">Particle</span> <span class="hlt">Filters</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Costa, Jose M J; Orlande, Helcio R B; Velho, Haroldo F Campos; de Pinho, Suani T R; Dulikravich, George S; Cotta, Renato M; da Cunha Neto, Silvio H</p> <p>2015-07-01</p> <p>Cancer is characterized by the uncontrolled growth of cells with the ability of invading local organs and/or tissues and of spreading to other sites. Several kinds of mathematical models have been proposed in the literature, involving different levels of refinement, for the evolution of tumors and their interactions with chemotherapy drugs. In this article, we present the solution of a state estimation problem for tumor size evolution. A system of nonlinear ordinary differential equations is used as the state evolution model, which involves as state variables the numbers of tumor, normal and angiogenic cells, as well as the masses of the chemotherapy and anti-angiogenic drugs in the body. Measurements of the numbers of tumor and normal cells are considered available for the inverse analysis. Parameters appearing in the formulation of the state evolution model are treated as Gaussian random variables and their uncertainties are taken into account in the estimation of the state variables, by using an algorithm based on the auxiliary sampling importance resampling <span class="hlt">particle</span> <span class="hlt">filter</span>. Test cases are examined in the article dealing with a chemotherapy protocol for pancreatic cancer. PMID:25973723</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130012659','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130012659"><span id="translatedtitle">Surface Navigation Using <span class="hlt">Optimized</span> Waypoints and <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Birge, Brian</p> <p>2013-01-01</p> <p>The design priority for manned space exploration missions is almost always placed on human safety. Proposed manned surface exploration tasks (lunar, asteroid sample returns, Mars) have the possibility of astronauts traveling several kilometers away from a home base. Deviations from preplanned paths are expected while exploring. In a time-critical emergency situation, there is a need to develop an <span class="hlt">optimal</span> home base return path. The return path may or may not be similar to the outbound path, and what defines <span class="hlt">optimal</span> may change with, and even within, each mission. A novel path planning algorithm and prototype program was developed using biologically inspired <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO) that generates an <span class="hlt">optimal</span> path of traversal while avoiding obstacles. Applications include emergency path planning on lunar, Martian, and/or asteroid surfaces, generating multiple scenarios for outbound missions, Earth-based search and rescue, as well as human manual traversal and/or path integration into robotic control systems. The strategy allows for a changing environment, and can be re-tasked at will and run in real-time situations. Given a random extraterrestrial planetary or small body surface position, the goal was to find the fastest (or shortest) path to an arbitrary position such as a safe zone or geographic objective, subject to possibly varying constraints. The problem requires a workable solution 100% of the time, though it does not require the absolute theoretical optimum. Obstacles should be avoided, but if they cannot be, then the algorithm needs to be smart enough to recognize this and deal with it. With some modifications, it works with non-stationary error topologies as well.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23590456','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23590456"><span id="translatedtitle">Ultrafine <span class="hlt">particle</span> removal by residential heating, ventilating, and air-conditioning <span class="hlt">filters</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stephens, B; Siegel, J A</p> <p>2013-12-01</p> <p>This work uses an in situ <span class="hlt">filter</span> test method to measure the size-resolved removal efficiency of indoor-generated ultrafine <span class="hlt">particles</span> (approximately 7-100 nm) for six new commercially available <span class="hlt">filters</span> installed in a recirculating heating, ventilating, and air-conditioning (HVAC) system in an unoccupied test house. The fibrous HVAC <span class="hlt">filters</span> were previously rated by the manufacturers according to ASHRAE Standard 52.2 and ranged from shallow (2.5 cm) fiberglass panel <span class="hlt">filters</span> (MERV 4) to deep-bed (12.7 cm) electrostatically charged synthetic media <span class="hlt">filters</span> (MERV 16). Measured removal efficiency ranged from 0 to 10% for most ultrafine <span class="hlt">particles</span> (UFP) sizes with the lowest rated <span class="hlt">filters</span> (MERV 4 and 6) to 60-80% for most UFP sizes with the highest rated <span class="hlt">filter</span> (MERV 16). The deeper bed <span class="hlt">filters</span> generally achieved higher removal efficiencies than the panel <span class="hlt">filters</span>, while maintaining a low pressure drop and higher airflow rate in the operating HVAC system. Assuming constant efficiency, a modeling effort using these measured values for new <span class="hlt">filters</span> and other inputs from real buildings shows that MERV 13-16 <span class="hlt">filters</span> could reduce the indoor proportion of outdoor UFPs (in the absence of indoor sources) by as much as a factor of 2-3 in a typical single-family residence relative to the lowest efficiency <span class="hlt">filters</span>, depending in part on <span class="hlt">particle</span> size. PMID:23590456</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016OptCo.358..132B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016OptCo.358..132B"><span id="translatedtitle"><span class="hlt">Optimization</span> of the performances of correlation <span class="hlt">filters</span> by pre-processing the input plane</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bouzidi, F.; Elbouz, M.; Alfalou, A.; Brosseau, C.; Fakhfakh, A.</p> <p>2016-01-01</p> <p>We report findings on the <span class="hlt">optimization</span> of the performances of correlation <span class="hlt">filters</span>. First, we propound and validate an <span class="hlt">optimization</span> of ROC curves adapted to correlation technique. Then, analysis suggests that a pre-processing of the input plane leads to a compromise between the robustness of the adapted <span class="hlt">filter</span> and the discrimination of the inverse <span class="hlt">filter</span> for face recognition applications. Rewardingly, our technical results demonstrate that this method is remarkably efficient to increase the performances of a VanderLugt correlator.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24369656','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24369656"><span id="translatedtitle">[Research on engine remaining useful life prediction based on oil spectrum analysis and <span class="hlt">particle</span> <span class="hlt">filtering</span>].</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sun, Lei; Jia, Yun-xian; Cai, Li-ying; Lin, Guo-yu; Zhao, Jin-song</p> <p>2013-09-01</p> <p>The spectrometric oil analysis(SOA) is an important technique for machine state monitoring, fault diagnosis and prognosis, and SOA based remaining useful life(RUL) prediction has an advantage of finding out the <span class="hlt">optimal</span> maintenance strategy for machine system. Because the complexity of machine system, its health state degradation process can't be simply characterized by linear model, while <span class="hlt">particle</span> <span class="hlt">filtering</span>(PF) possesses obvious advantages over traditional Kalman <span class="hlt">filtering</span> for dealing nonlinear and non-Gaussian system, the PF approach was applied to state forecasting by SOA, and the RUL prediction technique based on SOA and PF algorithm is proposed. In the prediction model, according to the estimating result of system's posterior probability, its prior probability distribution is realized, and the multi-step ahead prediction model based on PF algorithm is established. Finally, the practical SOA data of some engine was analyzed and forecasted by the above method, and the forecasting result was compared with that of traditional Kalman <span class="hlt">filtering</span> method. The result fully shows the superiority and effectivity of the PMID:24369656</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002SPIE.4792..193B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002SPIE.4792..193B"><span id="translatedtitle">Continuous and Discrete Space <span class="hlt">Particle</span> <span class="hlt">Filters</span> for Predictions in Acoustic Positioning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bauer, Will; Kim, Surrey; Kouritzin, Michael A.</p> <p>2002-12-01</p> <p>Predicting the future state of a random dynamic signal based on corrupted, distorted, and partial observations is vital for proper real-time control of a system that includes time delay. Motivated by problems from Acoustic Positioning Research Inc., we consider the continual automated illumination of an object moving within a bounded domain, which requires object location prediction due to inherent mechanical and physical time lags associated with robotic lighting. Quality computational predictions demand high fidelity models for the coupled moving object signal and observation equipment pair. In our current problem, the signal represents the vector position, orientation, and velocity of a stage performer. Acoustic observations are formed by timing ultrasonic waves traveling from four perimeter speakers to a microphone attached to the performer. The goal is to schedule lighting movements that are coordinated with the performer by anticipating his/her future position based upon these observations using <span class="hlt">filtering</span> theory. <span class="hlt">Particle</span> system based methods have experienced rapid development and have become an essential technique of contemporary <span class="hlt">filtering</span> strategies. Hitherto, researchers have largely focused on continuous state <span class="hlt">particle</span> <span class="hlt">filters</span>, ranging from traditional weighted <span class="hlt">particle</span> <span class="hlt">filters</span> to adaptive refining <span class="hlt">particle</span> <span class="hlt">filters</span>, readily able to perform path-space estimation and prediction. Herein, we compare the performance of a state-of-the-art refining <span class="hlt">particle</span> <span class="hlt">filter</span> to that of a novel discrete-space <span class="hlt">particle</span> <span class="hlt">filter</span> on the acoustic positioning problem. By discrete space <span class="hlt">particle</span> <span class="hlt">filter</span> we mean a Markov chain that counts <span class="hlt">particles</span> in discretized cells of the signal state space in order to form an approximated unnormalized distribution of the signal state. For both <span class="hlt">filters</span> mentioned above, we will examine issues like the mean time to localize a signal, the fidelity of <span class="hlt">filter</span> estimates at various signal to noise ratios, computational costs, and the effect of signal fading; furthermore, we will provide visual demonstrations of <span class="hlt">filter</span> performance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/8497560','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/8497560"><span id="translatedtitle"><span class="hlt">Optimal</span> digital <span class="hlt">filters</span> for long-latency components of the event-related brain potential.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Farwell, L A; Martinerie, J M; Bashore, T R; Rapp, P E; Goddard, P H</p> <p>1993-05-01</p> <p>A fundamentally important problem for cognitive psychophysiologists is selection of the appropriate off-line digital <span class="hlt">filter</span> to extract signal from noise in the event-related brain potential (ERP) recorded at the scalp. Investigators in the field typically use a type of finite impulse response (FIR) <span class="hlt">filter</span> known as moving average or boxcar <span class="hlt">filter</span> to achieve this end. However, this type of <span class="hlt">filter</span> can produce significant amplitude diminution and distortion of the shape of the ERP waveform. Thus, there is a need to identify more appropriate <span class="hlt">filters</span>. In this paper, we compare the performance of another type of FIR <span class="hlt">filter</span> that, unlike the boxcar <span class="hlt">filter</span>, is designed with an <span class="hlt">optimizing</span> algorithm that reduces signal distortion and maximizes signal extraction (referred to here as an <span class="hlt">optimal</span> FIR <span class="hlt">filter</span>). We applied several different <span class="hlt">filters</span> of both types to ERP data containing the P300 component. This comparison revealed that boxcar <span class="hlt">filters</span> reduced the contribution of high-frequency noise to the ERP but in so doing produced a substantial attenuation of P300 amplitude and, in some cases, substantial distortions of the shape of the waveform, resulting in significant errors in latency estimation. In contrast, the <span class="hlt">optimal</span> FIR <span class="hlt">filters</span> preserved P300 amplitude, morphology, and latency and also eliminated high-frequency noise more effectively than did the boxcar <span class="hlt">filters</span>. The implications of these results for data acquisition and analysis are discussed. PMID:8497560</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JPhCS.484a2047P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JPhCS.484a2047P"><span id="translatedtitle">Cosmological parameter estimation using <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prasad, J.; Souradeep, T.</p> <p>2014-03-01</p> <p>Constraining parameters of a theoretical model from observational data is an important exercise in cosmology. There are many theoretically motivated models, which demand greater number of cosmological parameters than the standard model of cosmology uses, and make the problem of parameter estimation challenging. It is a common practice to employ Bayesian formalism for parameter estimation for which, in general, likelihood surface is probed. For the standard cosmological model with six parameters, likelihood surface is quite smooth and does not have local maxima, and sampling based methods like Markov Chain Monte Carlo (MCMC) method are quite successful. However, when there are a large number of parameters or the likelihood surface is not smooth, other methods may be more effective. In this paper, we have demonstrated application of another method inspired from artificial intelligence, called <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) for estimating cosmological parameters from Cosmic Microwave Background (CMB) data taken from the WMAP satellite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPRS..105....1J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPRS..105....1J"><span id="translatedtitle"><span class="hlt">Particle</span> <span class="hlt">filtering</span> methods for georeferencing panoramic image sequence in complex urban scenes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ji, Shunping; Shi, Yun; Shan, Jie; Shao, Xiaowei; Shi, Zhongchao; Yuan, Xiuxiao; Yang, Peng; Wu, Wenbin; Tang, Huajun; Shibasaki, Ryosuke</p> <p>2015-07-01</p> <p>Georeferencing image sequences is critical for mobile mapping systems. Traditional methods such as bundle adjustment need adequate and well-distributed ground control points (GCP) when accurate GPS data are not available in complex urban scenes. For applications of large areas, automatic extraction of GCPs by matching vehicle-born image sequences with geo-referenced ortho-images will be a better choice than intensive GCP collection with field surveying. However, such image matching generated GCP's are highly noisy, especially in complex urban street environments due to shadows, occlusions and moving objects in the ortho images. This study presents a probabilistic solution that integrates matching and localization under one framework. First, a probabilistic and global localization model is formulated based on the Bayes' rules and Markov chain. Unlike many conventional methods, our model can accommodate non-Gaussian observation. In the next step, a <span class="hlt">particle</span> <span class="hlt">filtering</span> method is applied to determine this model under highly noisy GCP's. Owing to the multiple hypotheses tracking represented by diverse <span class="hlt">particles</span>, the method can balance the strength of geometric and radiometric constraints, i.e., drifted motion models and noisy GCP's, and guarantee an approximately <span class="hlt">optimal</span> trajectory. Carried out tests are with thousands of mobile panoramic images and aerial ortho-images. Comparing with the conventional extended Kalman <span class="hlt">filtering</span> and a global registration method, the proposed approach can succeed even under more than 80% gross errors in GCP's and reach a good accuracy equivalent to the traditional bundle adjustment with dense and precise control.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002NIMPA.480..726C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002NIMPA.480..726C"><span id="translatedtitle"><span class="hlt">Optimal</span> measurement of signal over noise ratio with constrained <span class="hlt">filter</span> transfer functions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cattaneo, Paolo Walter</p> <p>2002-03-01</p> <p>The problem of <span class="hlt">optimal</span> measurement of a signal in presence of noise is treated in detail by Baldinger and Franzen (Adv. Electron. Electron Phys. 8 (1956) 225), Radeka and Karlovac (Nucl. Instr. and Meth. 52 (1967) 86) and Gatti and Manfredi (La Rivista Nuovo Cimento 9(1) (1986) 1), and the <span class="hlt">filter</span> transfer function <span class="hlt">optimizing</span> the signal over noise ratio is well known. These calculations deals with unconstrained <span class="hlt">optimization</span>, that is the <span class="hlt">filter</span> transfer function may assume any value. In this paper functional analysis techniques are applied to <span class="hlt">optimize</span> the <span class="hlt">filter</span> transfer function in presence of linear constraints.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22225057','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22225057"><span id="translatedtitle">ASME AG-1 Section FC Qualified HEPA <span class="hlt">Filters</span>; a <span class="hlt">Particle</span> Loading Comparison - 13435</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Stillo, Andrew; Ricketts, Craig I.</p> <p>2013-07-01</p> <p>High Efficiency Particulate Air (HEPA) <span class="hlt">Filters</span> used to protect personnel, the public and the environment from airborne radioactive materials are designed, manufactured and qualified in accordance with ASME AG-1 Code section FC (HEPA <span class="hlt">Filters</span>) [1]. The qualification process requires that <span class="hlt">filters</span> manufactured in accordance with this ASME AG-1 code section must meet several performance requirements. These requirements include performance specifications for resistance to airflow, aerosol penetration, resistance to rough handling, resistance to pressure (includes high humidity and water droplet exposure), resistance to heated air, spot flame resistance and a visual/dimensional inspection. None of these requirements evaluate the <span class="hlt">particle</span> loading capacity of a HEPA <span class="hlt">filter</span> design. Concerns, over the <span class="hlt">particle</span> loading capacity, of the different designs included within the ASME AG-1 section FC code[1], have been voiced in the recent past. Additionally, the ability of a <span class="hlt">filter</span> to maintain its integrity, if subjected to severe operating conditions such as elevated relative humidity, fog conditions or elevated temperature, after loading in use over long service intervals is also a major concern. Although currently qualified HEPA <span class="hlt">filter</span> media are likely to have similar loading characteristics when evaluated independently, <span class="hlt">filter</span> pleat geometry can have a significant impact on the in-situ <span class="hlt">particle</span> loading capacity of <span class="hlt">filter</span> packs. Aerosol <span class="hlt">particle</span> characteristics, such as size and composition, may also have a significant impact on <span class="hlt">filter</span> loading capacity. Test results comparing <span class="hlt">filter</span> loading capacities for three different aerosol <span class="hlt">particles</span> and three different <span class="hlt">filter</span> pack configurations are reviewed. The information presented represents an empirical performance comparison among the <span class="hlt">filter</span> designs tested. The results may serve as a basis for further discussion toward the possible development of a <span class="hlt">particle</span> loading test to be included in the qualification requirements of ASME AG-1 Code sections FC and FK[1]. (authors)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JEPT...84.1267K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JEPT...84.1267K"><span id="translatedtitle">Evaporation of suspensions to form an incompressible cake and to fill <span class="hlt">filter</span> pores with solid <span class="hlt">particles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khuzhayorov, B. Kh.</p> <p>2011-11-01</p> <p>Equations of filtration of suspensions to form an incompressible cake of <span class="hlt">particles</span> on the surface of the <span class="hlt">filter</span> with simultaneous passage of a certain share of the <span class="hlt">particles</span> from the cake to the <span class="hlt">filter</span>'s pore space and next to the region of a <span class="hlt">filtered</span> liquid are derived from the principles of the mechanics of multiphase media. The influence of the travel of the <span class="hlt">particles</span> in the region of the cake and the <span class="hlt">filter</span> on the dynamics of growth of the cake bed is investigated. An analysis of the derived dynamic filtration equations shows that allowance for the factors of travel and accumulation of <span class="hlt">particles</span> in the cake and the <span class="hlt">filter</span> causes their total filtration resistance, in particular the resistance in the inertial component of the filtration law, to decrease.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006EJASP2006...30Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006EJASP2006...30Y"><span id="translatedtitle">The <span class="hlt">Optimal</span> Design of Weighted Order Statistics <span class="hlt">Filters</span> by Using Support Vector Machines</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yao, Chih-Chia; Yu, Pao-Ta</p> <p>2006-12-01</p> <p>Support vector machines (SVMs), a classification algorithm for the machine learning community, have been shown to provide higher performance than traditional learning machines. In this paper, the technique of SVMs is introduced into the design of weighted order statistics (WOS) <span class="hlt">filters</span>. WOS <span class="hlt">filters</span> are highly effective, in processing digital signals, because they have a simple window structure. However, due to threshold decomposition and stacking property, the development of WOS <span class="hlt">filters</span> cannot significantly improve both the design complexity and estimation error. This paper proposes a new designing technique which can improve the learning speed and reduce the complexity of designing WOS <span class="hlt">filters</span>. This technique uses a dichotomous approach to reduce the Boolean functions from 255 levels to two levels, which are separated by an <span class="hlt">optimal</span> hyperplane. Furthermore, the <span class="hlt">optimal</span> hyperplane is gotten by using the technique of SVMs. Our proposed method approximates the <span class="hlt">optimal</span> weighted order statistics <span class="hlt">filters</span> more rapidly than the adaptive neural <span class="hlt">filters</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011HESSD...8.3383N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011HESSD...8.3383N"><span id="translatedtitle">Applying sequential Monte Carlo methods into a distributed hydrologic model: lagged <span class="hlt">particle</span> <span class="hlt">filtering</span> approach with regularization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Noh, S. J.; Tachikawa, Y.; Shiiba, M.; Kim, S.</p> <p>2011-04-01</p> <p>Applications of data assimilation techniques have been widely used to improve hydrologic prediction. Among various data assimilation techniques, sequential Monte Carlo (SMC) methods, known as "<span class="hlt">particle</span> <span class="hlt">filters</span>", provide the capability to handle non-linear and non-Gaussian state-space models. In this paper, we propose an improved <span class="hlt">particle</span> <span class="hlt">filtering</span> approach to consider different response time of internal state variables in a hydrologic model. The proposed method adopts a lagged <span class="hlt">filtering</span> approach to aggregate model response until uncertainty of each hydrologic process is propagated. The regularization with an additional move step based on Markov chain Monte Carlo (MCMC) is also implemented to preserve sample diversity under the lagged <span class="hlt">filtering</span> approach. A distributed hydrologic model, WEP is implemented for the sequential data assimilation through the updating of state variables. <span class="hlt">Particle</span> <span class="hlt">filtering</span> is parallelized and implemented in the multi-core computing environment via open message passing interface (MPI). We compare performance results of <span class="hlt">particle</span> <span class="hlt">filters</span> in terms of model efficiency, predictive QQ plots and <span class="hlt">particle</span> diversity. The improvement of model efficiency and the preservation of <span class="hlt">particle</span> diversity are found in the lagged regularized <span class="hlt">particle</span> <span class="hlt">filter</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EJASP2014...95H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EJASP2014...95H"><span id="translatedtitle">Multiple local feature representations and their fusion based on an SVR model for iris recognition using <span class="hlt">optimized</span> Gabor <span class="hlt">filters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>He, Fei; Liu, Yuanning; Zhu, Xiaodong; Huang, Chun; Han, Ye; Dong, Hongxing</p> <p>2014-12-01</p> <p>Gabor descriptors have been widely used in iris texture representations. However, fixed basic Gabor functions cannot match the changing nature of diverse iris datasets. Furthermore, a single form of iris feature cannot overcome difficulties in iris recognition, such as illumination variations, environmental conditions, and device variations. This paper provides multiple local feature representations and their fusion scheme based on a support vector regression (SVR) model for iris recognition using <span class="hlt">optimized</span> Gabor <span class="hlt">filters</span>. In our iris system, a <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO)- and a Boolean <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (BPSO)-based algorithm is proposed to provide suitable Gabor <span class="hlt">filters</span> for each involved test dataset without predefinition or manual modulation. Several comparative experiments on JLUBR-IRIS, CASIA-I, and CASIA-V4-Interval iris datasets are conducted, and the results show that our work can generate improved local Gabor features by using <span class="hlt">optimized</span> Gabor <span class="hlt">filters</span> for each dataset. In addition, our SVR fusion strategy may make full use of their discriminative ability to improve accuracy and reliability. Other comparative experiments show that our approach may outperform other popular iris systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JIEIB..94..285S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JIEIB..94..285S"><span id="translatedtitle">Teaching-learning-based <span class="hlt">Optimization</span> Algorithm for Parameter Identification in the Design of IIR <span class="hlt">Filters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Singh, R.; Verma, H. K.</p> <p>2013-12-01</p> <p>This paper presents a teaching-learning-based <span class="hlt">optimization</span> (TLBO) algorithm to solve parameter identification problems in the designing of digital infinite impulse response (IIR) <span class="hlt">filter</span>. TLBO based <span class="hlt">filter</span> modelling is applied to calculate the parameters of unknown plant in simulations. Unlike other heuristic search algorithms, TLBO algorithm is an algorithm-specific parameter-less algorithm. In this paper big bang-big crunch (BB-BC) <span class="hlt">optimization</span> and PSO algorithms are also applied to <span class="hlt">filter</span> design for comparison. Unknown <span class="hlt">filter</span> parameters are considered as a vector to be <span class="hlt">optimized</span> by these algorithms. MATLAB programming is used for implementation of proposed algorithms. Experimental results show that the TLBO is more accurate to estimate the <span class="hlt">filter</span> parameters than the BB-BC <span class="hlt">optimization</span> algorithm and has faster convergence rate when compared to PSO algorithm. TLBO is used where accuracy is more essential than the convergence speed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009IJTPE.129..733K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009IJTPE.129..733K"><span id="translatedtitle">Determination Method for <span class="hlt">Optimal</span> Installation of Active <span class="hlt">Filters</span> in Distribution Network with Distributed Generation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kawasaki, Shoji; Hayashi, Yasuhiro; Matsuki, Junya; Kikuya, Hirotaka; Hojo, Masahide</p> <p></p> <p>Recently, the harmonic troubles in a distribution network are worried in the background of the increase of the connection of distributed generation (DG) and the spread of the power electronics equipments. As one of the strategies, control the harmonic voltage by installing an active <span class="hlt">filter</span> (AF) has been researched. In this paper, the authors propose a computation method to determine the <span class="hlt">optimal</span> allocations, gains and installation number of AFs so as to minimize the maximum value of voltage total harmonic distortion (THD) for a distribution network with DGs. The developed method is based on <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO) which is one of the nonlinear <span class="hlt">optimization</span> methods. Especially, in this paper, the case where the harmonic voltage or the harmonic current in a distribution network is assumed by connecting many DGs through the inverters, and the authors propose a determination method of the <span class="hlt">optimal</span> allocation and gain of AF that has the harmonic restrictive effect in the whole distribution network. Moreover, the authors propose also about a determination method of the necessary minimum installation number of AFs, by taking into consideration also about the case where the target value of harmonic suppression cannot be reached, by one set only of AF. In order to verify the validity and effectiveness of the proposed method, the numerical simulations are carried out by using an analytical model of distribution network with DGs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/823418','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/823418"><span id="translatedtitle"><span class="hlt">PARTICLE</span> TRANSPORTATION AND DEPOSITION IN HOT GAS <span class="hlt">FILTER</span> VESSELS - A COMPUTATIONAL AND EXPERIMENTAL MODELING APPROACH</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Goodarz Ahmadi</p> <p>2002-07-01</p> <p>In this project, a computational modeling approach for analyzing flow and ash transport and deposition in <span class="hlt">filter</span> vessels was developed. An Eulerian-Lagrangian formulation for studying hot-gas filtration process was established. The approach uses an Eulerian analysis of gas flows in the <span class="hlt">filter</span> vessel, and makes use of the Lagrangian trajectory analysis for the <span class="hlt">particle</span> transport and deposition. Particular attention was given to the Siemens-Westinghouse <span class="hlt">filter</span> vessel at Power System Development Facility in Wilsonville in Alabama. Details of hot-gas flow in this tangential flow <span class="hlt">filter</span> vessel are evaluated. The simulation results show that the rapidly rotation flow in the spacing between the shroud and the vessel refractory acts as cyclone that leads to the removal of a large fraction of the larger <span class="hlt">particles</span> from the gas stream. Several alternate designs for the <span class="hlt">filter</span> vessel are considered. These include a vessel with a short shroud, a <span class="hlt">filter</span> vessel with no shroud and a vessel with a deflector plate. The hot-gas flow and <span class="hlt">particle</span> transport and deposition in various vessels are evaluated. The deposition patterns in various vessels are compared. It is shown that certain <span class="hlt">filter</span> vessel designs allow for the large <span class="hlt">particles</span> to remain suspended in the gas stream and to deposit on the <span class="hlt">filters</span>. The presence of the larger <span class="hlt">particles</span> in the <span class="hlt">filter</span> cake leads to lower mechanical strength thus allowing for the back-pulse process to more easily remove the <span class="hlt">filter</span> cake. A laboratory-scale <span class="hlt">filter</span> vessel for testing the cold flow condition was designed and fabricated. A laser-based flow visualization technique is used and the gas flow condition in the laboratory-scale vessel was experimental studied. A computer model for the experimental vessel was also developed and the gas flow and <span class="hlt">particle</span> transport patterns are evaluated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060028978&hterms=Kalman&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DKalman','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060028978&hterms=Kalman&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DKalman"><span id="translatedtitle">An <span class="hlt">optimal</span> modification of a Kalman <span class="hlt">filter</span> for time scales</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Greenhall, C. A.</p> <p>2003-01-01</p> <p>The Kalman <span class="hlt">filter</span> in question, which was implemented in the time scale algorithm TA(NIST), produces time scales with poor short-term stability. A simple modification of the error covariance matrix allows the <span class="hlt">filter</span> to produce time scales with good stability at all averaging times, as verified by simulations of clock ensembles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21682358','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21682358"><span id="translatedtitle">A <span class="hlt">particle</span> <span class="hlt">filtering</span> approach for spatial arrival time tracking in ocean acoustics.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jain, Rashi; Michalopoulou, Zoi-Heleni</p> <p>2011-06-01</p> <p>The focus of this work is on arrival time and amplitude estimation from acoustic signals recorded at spatially separated hydrophones in the ocean. A <span class="hlt">particle</span> <span class="hlt">filtering</span> approach is developed that treats arrival times as "targets" and tracks their "location" across receivers, also modeling arrival time gradient. The method is evaluated via Monte Carlo simulations and is compared to a maximum likelihood estimator, which does not relate arrivals at neighboring receivers. The comparison demonstrates a significant advantage in using the <span class="hlt">particle</span> <span class="hlt">filter</span>. It is also shown that posterior probability density functions of times and amplitudes become readily available with <span class="hlt">particle</span> <span class="hlt">filtering</span>. PMID:21682358</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006SPIE.6159E..4KB','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006SPIE.6159E..4KB"><span id="translatedtitle">Farrow structure implementation of fractional delay <span class="hlt">filter</span> <span class="hlt">optimal</span> in Chebyshev sense</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Blok, Marek</p> <p>2006-03-01</p> <p>In this paper the problem of variable delay <span class="hlt">filter</span> implementation based on the Farrow structure is discussed. The idea of such an implementation is to calculate, for each required delay, coefficients of fractional delay <span class="hlt">filter</span> impulse response using delay independent polynomials. This approach leads to significant decrease of computational costs in applications which require frequent delay changes. Achieved computational complexity reduction is especially important in case of recursive <span class="hlt">optimal</span> <span class="hlt">filters</span> design methods. In this paper we demonstrate that quality and properties of fractional delay <span class="hlt">filters</span> <span class="hlt">optimal</span> in Chebyshev sense can be retained even for low orders of the Farrow structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21608686','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21608686"><span id="translatedtitle">Optease Vena Cava <span class="hlt">Filter</span> <span class="hlt">Optimal</span> Indwelling Time and Retrievability</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rimon, Uri Bensaid, Paul Golan, Gil Garniek, Alexander Khaitovich, Boris; Dotan, Zohar; Konen, Eli</p> <p>2011-06-15</p> <p>The purpose of this study was to assess the indwelling time and retrievability of the Optease IVC <span class="hlt">filter</span>. Between 2002 and 2009, a total of 811 Optease <span class="hlt">filters</span> were inserted: 382 for prophylaxis in multitrauma patients and 429 for patients with venous thromboembolic (VTE) disease. In 139 patients [97 men and 42 women; mean age, 36 (range, 17-82) years], <span class="hlt">filter</span> retrieval was attempted. They were divided into two groups to compare change in retrieval policy during the years: group A, 60 patients with <span class="hlt">filter</span> retrievals performed before December 31 2006; and group B, 79 patients with <span class="hlt">filter</span> retrievals from January 2007 to October 2009. A total of 128 <span class="hlt">filters</span> were successfully removed (57 in group A, and 71 in group B). The mean <span class="hlt">filter</span> indwelling time in the study group was 25 (range, 3-122) days. In group A the mean indwelling time was 18 (range, 7-55) days and in group B 31 days (range, 8-122). There were 11 retrieval failures: 4 for inability to engage the <span class="hlt">filter</span> hook and 7 for inability to sheathe the <span class="hlt">filter</span> due to intimal overgrowth. The mean indwelling time of group A retrieval failures was 16 (range, 15-18) days and in group B 54 (range, 17-122) days. Mean fluoroscopy time for successful retrieval was 3.5 (range, 1-16.6) min and for retrieval failures 25.2 (range, 7.2-62) min. Attempts to retrieve the Optease <span class="hlt">filter</span> can be performed up to 60 days, but more failures will be encountered with this approach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995ApOpt..34..346F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995ApOpt..34..346F"><span id="translatedtitle">Photorefractive two-beam coupling <span class="hlt">optimal</span> thresholding <span class="hlt">filter</span> for additive signal-dependent noise reduction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fu, Jack; Khoury, Jehad; Cronin-Golomb, Mark; Woods, Charles L.</p> <p>1995-01-01</p> <p>Computer simulations of photorefractive thresholding <span class="hlt">filters</span> for the reduction of artifact or dust noise demonstrate an increase in signal-to-noise ratio (SNR) of 70% to 95%, respectively, of that provided by the Wiener <span class="hlt">filter</span> for inputs with a SNR of approximately 3. These simple, nearly <span class="hlt">optimal</span> <span class="hlt">filters</span> use a spectral thresholding profile that is proportional to the envelope of the noise spectrum. Alternative nonlinear <span class="hlt">filters</span> with either 1/ nu or constant thresholding profiles increase the SNR almost as much as the noise-envelope thresholding <span class="hlt">filter</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NIMPA.808..150S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NIMPA.808..150S"><span id="translatedtitle"><span class="hlt">Optimized</span> digital <span class="hlt">filtering</span> techniques for radiation detection with HPGe detectors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salathe, Marco; Kihm, Thomas</p> <p>2016-02-01</p> <p>This paper describes state-of-the-art digital <span class="hlt">filtering</span> techniques that are part of GEANA, an automatic data analysis software used for the GERDA experiment. The discussed <span class="hlt">filters</span> include a novel, nonlinear correction method for ballistic deficits, which is combined with one of three shaping <span class="hlt">filters</span>: a pseudo-Gaussian, a modified trapezoidal, or a modified cusp <span class="hlt">filter</span>. The performance of the <span class="hlt">filters</span> is demonstrated with a 762 g Broad Energy Germanium (BEGe) detector, produced by Canberra, that measures γ-ray lines from radioactive sources in an energy range between 59.5 and 2614.5 keV. At 1332.5 keV, together with the ballistic deficit correction method, all <span class="hlt">filters</span> produce a comparable energy resolution of ~1.61 keV FWHM. This value is superior to those measured by the manufacturer and those found in publications with detectors of a similar design and mass. At 59.5 keV, the modified cusp <span class="hlt">filter</span> without a ballistic deficit correction produced the best result, with an energy resolution of 0.46 keV. It is observed that the loss in resolution by using a constant shaping time over the entire energy range is small when using the ballistic deficit correction method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3478865','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3478865"><span id="translatedtitle"><span class="hlt">Optimal</span> <span class="hlt">Filter</span> Estimation for Lucas-Kanade Optical Flow</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sharmin, Nusrat; Brad, Remus</p> <p>2012-01-01</p> <p>Optical flow algorithms offer a way to estimate motion from a sequence of images. The computation of optical flow plays a key-role in several computer vision applications, including motion detection and segmentation, frame interpolation, three-dimensional scene reconstruction, robot navigation and video compression. In the case of gradient based optical flow implementation, the pre-<span class="hlt">filtering</span> step plays a vital role, not only for accurate computation of optical flow, but also for the improvement of performance. Generally, in optical flow computation, <span class="hlt">filtering</span> is used at the initial level on original input images and afterwards, the images are resized. In this paper, we propose an image <span class="hlt">filtering</span> approach as a pre-processing step for the Lucas-Kanade pyramidal optical flow algorithm. Based on a study of different types of <span class="hlt">filtering</span> methods and applied on the Iterative Refined Lucas-Kanade, we have concluded on the best <span class="hlt">filtering</span> practice. As the Gaussian smoothing <span class="hlt">filter</span> was selected, an empirical approach for the Gaussian variance estimation was introduced. Tested on the Middlebury image sequences, a correlation between the image intensity value and the standard deviation value of the Gaussian function was established. Finally, we have found that our selection method offers a better performance for the Lucas-Kanade optical flow algorithm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26950130','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26950130"><span id="translatedtitle">Research on a Lamb Wave and <span class="hlt">Particle</span> <span class="hlt">Filter</span>-Based On-Line Crack Propagation Prognosis Method.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Jian; Yuan, Shenfang; Qiu, Lei; Cai, Jian; Yang, Weibo</p> <p>2016-01-01</p> <p>Prognostics and health management techniques have drawn widespread attention due to their ability to facilitate maintenance activities based on need. On-line prognosis of fatigue crack propagation can offer information for <span class="hlt">optimizing</span> operation and maintenance strategies in real-time. This paper proposes a Lamb wave-<span class="hlt">particle</span> <span class="hlt">filter</span> (LW-PF)-based method for on-line prognosis of fatigue crack propagation which takes advantages of the possibility of on-line monitoring to evaluate the actual crack length and uses a <span class="hlt">particle</span> <span class="hlt">filter</span> to deal with the crack evolution and monitoring uncertainties. The piezoelectric transducers (PZTs)-based active Lamb wave method is adopted for on-line crack monitoring. The state space model relating to crack propagation is established by the data-driven and finite element methods. Fatigue experiments performed on hole-edge crack specimens have validated the advantages of the proposed method. PMID:26950130</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4813895','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4813895"><span id="translatedtitle">Research on a Lamb Wave and <span class="hlt">Particle</span> <span class="hlt">Filter</span>-Based On-Line Crack Propagation Prognosis Method</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chen, Jian; Yuan, Shenfang; Qiu, Lei; Cai, Jian; Yang, Weibo</p> <p>2016-01-01</p> <p>Prognostics and health management techniques have drawn widespread attention due to their ability to facilitate maintenance activities based on need. On-line prognosis of fatigue crack propagation can offer information for <span class="hlt">optimizing</span> operation and maintenance strategies in real-time. This paper proposes a Lamb wave-<span class="hlt">particle</span> <span class="hlt">filter</span> (LW-PF)-based method for on-line prognosis of fatigue crack propagation which takes advantages of the possibility of on-line monitoring to evaluate the actual crack length and uses a <span class="hlt">particle</span> <span class="hlt">filter</span> to deal with the crack evolution and monitoring uncertainties. The piezoelectric transducers (PZTs)-based active Lamb wave method is adopted for on-line crack monitoring. The state space model relating to crack propagation is established by the data-driven and finite element methods. Fatigue experiments performed on hole-edge crack specimens have validated the advantages of the proposed method. PMID:26950130</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8783E..1FT','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8783E..1FT"><span id="translatedtitle">Research on the adaptive choice mechanism of proposal distribution in <span class="hlt">particle</span> <span class="hlt">filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tang, Yongli; Jin, Yan; Yu, Jinxia; Zhao, Qian</p> <p>2013-03-01</p> <p>With the inherent deficiency analysis of <span class="hlt">particle</span> <span class="hlt">filter</span> algorithm, proposal distribution with adaptive choice mechanism is studied. The adaptive mechanisms for proposal distribution include adaptive proposal distribution revised by the information derived from step-by-step Monte Carlo samples, Gaussian approximation adaptive proposal distribution, shrinking / growing adaptive proposal distribution, adaptive proposal distribution combined with other methods. At last, the simulations based on single object tracking are implemented, and the performance of the <span class="hlt">particle</span> <span class="hlt">filter</span> with adaptive proposal distribution is verified.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/793319','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/793319"><span id="translatedtitle"><span class="hlt">PARTICLE</span> TRANSPORT AND DEPOSITION IN THE HOT-GAS <span class="hlt">FILTER</span> AT WILSONVILLE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Goodarz Ahmadi</p> <p>1999-06-24</p> <p><span class="hlt">Particle</span> transport and deposition in the Wilsonville hot-gas <span class="hlt">filter</span> vessel is studied. The <span class="hlt">filter</span> vessel contains a total of 72 <span class="hlt">filters</span>, which are arranged in two tiers. These are modeled by six upper and one lower cylindrical effective <span class="hlt">filters</span>. An unstructured grid of 312,797 cells generated by GAMBIT is used in the simulations. The Reynolds stress model of FLUENT{trademark} (version 5.0) code is used for evaluating the gas mean velocities and root mean-square fluctuation velocities in the vessel. The <span class="hlt">particle</span> equation of motion includes the drag, the gravitational and the lift forces. The turbulent instantaneous fluctuation velocity is simulated by a <span class="hlt">filtered</span> Gaussian white-noise model provided by the FLUENT code. The <span class="hlt">particle</span> deposition patterns are evaluated, and the effect of <span class="hlt">particle</span> size is studied. The effect of turbulent dispersion, the lift force and the gravitational force are analyzed. The results show that the deposition pattern depends on <span class="hlt">particle</span> size. Turbulent dispersion plays an important role in transport and deposition of <span class="hlt">particles</span>. Lift and gravitational forces affect the motion of large <span class="hlt">particles</span>, but has no effect on small <span class="hlt">particles</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9474E..05M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9474E..05M"><span id="translatedtitle">Multisensor fusion for 3D target tracking using track-before-detect <span class="hlt">particle</span> <span class="hlt">filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moshtagh, Nima; Romberg, Paul M.; Chan, Moses W.</p> <p>2015-05-01</p> <p>This work presents a novel fusion mechanism for estimating the three-dimensional trajectory of a moving target using images collected by multiple imaging sensors. The proposed projective <span class="hlt">particle</span> <span class="hlt">filter</span> avoids the explicit target detection prior to fusion. In projective <span class="hlt">particle</span> <span class="hlt">filter</span>, <span class="hlt">particles</span> that represent the posterior density (of target state in a high-dimensional space) are projected onto the lower-dimensional observation space. Measurements are generated directly in the observation space (image plane) and a marginal (sensor) likelihood is computed. The <span class="hlt">particles</span> states and their weights are updated using the joint likelihood computed from all the sensors. The 3D state estimate of target (system track) is then generated from the states of the <span class="hlt">particles</span>. This approach is similar to track-before-detect <span class="hlt">particle</span> <span class="hlt">filters</span> that are known to perform well in tracking dim and stealthy targets in image collections. Our approach extends the track-before-detect approach to 3D tracking using the projective <span class="hlt">particle</span> <span class="hlt">filter</span>. The performance of this measurement-level fusion method is compared with that of a track-level fusion algorithm using the projective <span class="hlt">particle</span> <span class="hlt">filter</span>. In the track-level fusion algorithm, the 2D sensor tracks are generated separately and transmitted to a fusion center, where they are treated as measurements to the state estimator. The 2D sensor tracks are then fused to reconstruct the system track. A realistic synthetic scenario with a boosting target was generated, and used to study the performance of the fusion mechanisms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005SPIE.5772..144G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005SPIE.5772..144G"><span id="translatedtitle">Analysis and <span class="hlt">optimization</span> of the computational process of nonlinear discrete Kalman <span class="hlt">filtering</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gurov, Igor; Taratin, Mikhail; Zakharov, Alexey</p> <p>2005-06-01</p> <p><span class="hlt">Optimization</span> of nonlinear discrete Kalman <span class="hlt">filtering</span> computational process is considered in application to dynamic processing of interferometric signals in Optical Coherence Tomography. Processing speed of low-coherence fringe signals is assessed when using discrete nonlinear Kalman <span class="hlt">filtering</span> algorithm implemented by Intel Pentium 4 processor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70115387','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70115387"><span id="translatedtitle">Assessing consumption of bioactive micro-<span class="hlt">particles</span> by <span class="hlt">filter</span>-feeding Asian carp</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Jensen, Nathan R.; Amberg, Jon J.; Luoma, James A.; Walleser, Liza R.; Gaikowski, Mark P.</p> <p>2012-01-01</p> <p>Silver carp Hypophthalmichthys molitrix (SVC) and bighead carp H. nobilis (BHC) have impacted waters in the US since their escape. Current chemical controls for aquatic nuisance species are non-selective. Development of a bioactive micro-<span class="hlt">particle</span> that exploits <span class="hlt">filter</span>-feeding habits of SVC or BHC could result in a new control tool. It is not fully understood if SVC or BHC will consume bioactive micro-<span class="hlt">particles</span>. Two discrete trials were performed to: 1) evaluate if SVC and BHC consume the candidate micro-<span class="hlt">particle</span> formulation; 2) determine what size they consume; 3) establish methods to evaluate consumption of <span class="hlt">filter</span>-feeders for future experiments. Both SVC and BHC were exposed to small (50-100 μm) and large (150-200 μm) micro-<span class="hlt">particles</span> in two 24-h trials. <span class="hlt">Particles</span> in water were counted electronically and manually (microscopy). <span class="hlt">Particles</span> on gill rakers were counted manually and intestinal tracts inspected for the presence of micro-<span class="hlt">particles</span>. In Trial 1, both manual and electronic count data confirmed reductions of both size <span class="hlt">particles</span>; SVC appeared to remove more small <span class="hlt">particles</span> than large; more BHC consumed <span class="hlt">particles</span>; SVC had fewer overall <span class="hlt">particles</span> in their gill rakers than BHC. In Trial 2, electronic counts confirmed reductions of both size <span class="hlt">particles</span>; both SVC and BHC consumed <span class="hlt">particles</span>, yet more SVC consumed micro-<span class="hlt">particles</span> compared to BHC. Of the fish that ate micro-<span class="hlt">particles</span>, SVC consumed more than BHC. It is recommended to use multiple metrics to assess consumption of candidate micro-<span class="hlt">particles</span> by <span class="hlt">filter</span>-feeders when attempting to distinguish differential <span class="hlt">particle</span> consumption. This study has implications for developing micro-<span class="hlt">particles</span> for species-specific delivery of bioactive controls to help fisheries, provides some methods for further experiments with bioactive micro-<span class="hlt">particles</span>, and may also have applications in aquaculture.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/11549143','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/11549143"><span id="translatedtitle"><span class="hlt">Particle</span> emission characteristics of <span class="hlt">filter</span>-equipped vacuum cleaners.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Trakumas, S; Willeke, K; Grinshpun, S A; Reponen, T; Mainelis, G; Friedman, W</p> <p>2001-01-01</p> <p>Industrial vacuum cleaners with final high-efficiency particulate air (HEPA) <span class="hlt">filters</span> traditionally have been used for cleanup operations in which all of the nozzle-entrained dust must be collected with high efficiency, for example, after lead-based paint abatement in homes. In this study household vacuum cleaners ranging from $70 to $650 and an industrial vacuum cleaner costing more than $1400 were evaluated relative to their collection efficiency immediately after installing new primary dust collectors in them. Using newly developed testing technology, some of the low-cost household vacuum cleaners equipped with a final HEPA <span class="hlt">filter</span> were found to have initial overall filtration efficiencies comparable to those of industrial vacuum cleaners equipped with a final HEPA <span class="hlt">filter</span>. The household vacuum cleaners equipped with a final HEPA <span class="hlt">filter</span> efficiently collect about 100% of the dry dust entrained by the nozzle. For extensive cleaning efforts and for vacuum cleaning of wet surfaces, however, industrial vacuum cleaners may have an advantage, including ruggedness and greater loading capacity. The methods and findings of this study are applicable to field evaluations of vacuum cleaners. PMID:11549143</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AtmEn..77..385C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AtmEn..77..385C"><span id="translatedtitle">Use of Nuclepore <span class="hlt">filters</span> for ambient and workplace nanoparticle exposure assessment-Spherical <span class="hlt">particles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Sheng-Chieh; Wang, Jing; Fissan, Heinz; Pui, David Y. H.</p> <p>2013-10-01</p> <p>Nuclepore <span class="hlt">filter</span> collection with subsequent electron microscopy analysis for nanoparticles was carried out to examine the feasibility of the method to assess the nanoparticle exposure. The number distribution of nanoparticles collected on the <span class="hlt">filter</span> surface was counted visually and converted to the distribution in the air using existing filtration models for Nuclepore <span class="hlt">filters</span>. To search for a proper model, this paper studied the overall penetrations of three different nanoparticles (PSL, Ag and NaCl), covering a wide range of <span class="hlt">particle</span> sizes (20-800 nm) and densities (1.05-10.5 g cm-3), through Nuclepore <span class="hlt">filters</span> with two different pore diameters (1 and 3 μm) and different face velocities (2-15 cm s-1). The data were compared with existing <span class="hlt">particle</span> deposition models and modified models proposed by this study, which delivered different results because of different deposition processes considered. It was found that a parameter associated with flow condition and <span class="hlt">filter</span> geometry (density of fluid medium, <span class="hlt">particle</span> density, filtration face velocity, <span class="hlt">filter</span> porosity and pore diameter) should be taken into account to verify the applicability of the models. The data of the overall penetration were in very good agreement with the properly applied models. A good agreement of <span class="hlt">filter</span> surface collection between the validated model and the SEM analysis was obtained, indicating a correct nanoparticle number distribution in the air can be converted from the Nuclepore <span class="hlt">filter</span> surface collection and this method can be applied for nanoparticle exposure assessment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/913143','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/913143"><span id="translatedtitle">Method for <span class="hlt">optimizing</span> output in ultrashort-pulse multipass laser amplifiers with selective use of a spectral <span class="hlt">filter</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Backus, Sterling J.; Kapteyn, Henry C.</p> <p>2007-07-10</p> <p>A method for <span class="hlt">optimizing</span> multipass laser amplifier output utilizes a spectral <span class="hlt">filter</span> in early passes but not in later passes. The pulses shift position slightly for each pass through the amplifier, and the <span class="hlt">filter</span> is placed such that early passes intersect the <span class="hlt">filter</span> while later passes bypass it. The <span class="hlt">filter</span> position may be adjust offline in order to adjust the number of passes in each category. The <span class="hlt">filter</span> may be <span class="hlt">optimized</span> for use in a cryogenic amplifier.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25016201','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25016201"><span id="translatedtitle">Comparison of the performance of <span class="hlt">particle</span> <span class="hlt">filter</span> algorithms applied to tracking of a disease epidemic.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sheinson, Daniel M; Niemi, Jarad; Meiring, Wendy</p> <p>2014-09-01</p> <p>We present general methodology for sequential inference in nonlinear stochastic state-space models to simultaneously estimate dynamic states and fixed parameters. We show that basic <span class="hlt">particle</span> <span class="hlt">filters</span> may fail due to degeneracy in fixed parameter estimation and suggest the use of a kernel density approximation to the <span class="hlt">filtered</span> distribution of the fixed parameters to allow the fixed parameters to regenerate. In addition, we show that "seemingly" uninformative uniform priors on fixed parameters can affect posterior inferences and suggest the use of priors bounded only by the support of the parameter. We show the negative impact of using multinomial resampling and suggest the use of either stratified or residual resampling within the <span class="hlt">particle</span> <span class="hlt">filter</span>. As a motivating example, we use a model for tracking and prediction of a disease outbreak via a syndromic surveillance system. Finally, we use this improved <span class="hlt">particle</span> <span class="hlt">filtering</span> methodology to relax prior assumptions on model parameters yet still provide reasonable estimates for model parameters and disease states. PMID:25016201</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=115033&keyword=ventilation+AND+rate+AND+exercise&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=72562777&CFTOKEN=36184242','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=115033&keyword=ventilation+AND+rate+AND+exercise&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=72562777&CFTOKEN=36184242"><span id="translatedtitle">NASAL <span class="hlt">FILTERING</span> OF FINE <span class="hlt">PARTICLES</span> IN CHILDREN VS. ADULTS</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Nasal efficiency for removing fine <span class="hlt">particles</span> may be affected by developmental changes in nasal structure associated with age. In healthy Caucasian children (age 6-13, n=17) and adults (age 18-28, n=11) we measured the fractional deposition (DF) of fine <span class="hlt">particles</span> (1 and 2um MMAD)...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PASJ...64...47O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PASJ...64...47O"><span id="translatedtitle">Wide-Band Optical <span class="hlt">Filter</span> <span class="hlt">Optimized</span> for Deep Imaging of Small Solar System Bodies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Okumura, Shin-ichiro; Nishiyama, Kota; Urakawa, Seitaro; Sakamoto, Tsuyoshi; Takahashi, Noritsugu; Yoshikawa, Makoto</p> <p>2012-06-01</p> <p>This paper describes a newly designed wide-band optical <span class="hlt">filter</span>. It is <span class="hlt">optimized</span> for deep imaging of small solar-system bodies. The new <span class="hlt">filter</span>, which we denote as W i, is designed to reduce contamination by light pollution from street lamps, especially strong mercury and sodium emission lines. It is also useful for reducing unwanted scattered moonlight. Compared with the use of a commercially available long-wave cut wide-band <span class="hlt">filter</span>, the signal-to-noise ratios in the detection of asteroids are improved by about 6% by using the W i <span class="hlt">filter</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhB...48r5001Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhB...48r5001Z"><span id="translatedtitle"><span class="hlt">Optimization</span> of atomic Faraday <span class="hlt">filters</span> in the presence of homogeneous line broadening</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zentile, Mark A.; Keaveney, James; Mathew, Renju S.; Whiting, Daniel J.; Adams, Charles S.; Hughes, Ifan G.</p> <p>2015-09-01</p> <p>We show that homogeneous line broadening drastically affects the performance of atomic Faraday <span class="hlt">filters</span>. We study the effects of cell length and find that the behaviour of line-centre <span class="hlt">filters</span> are quite different from wing-type <span class="hlt">filters</span>, where the effect of self-broadening is found to be particularly important. We use a computer <span class="hlt">optimization</span> algorithm to find the best magnetic field and temperature for Faraday <span class="hlt">filters</span> with a range of cell lengths, and experimentally realize one particular example using a micro-fabricated 87Rb vapour cell. We find excellent agreement between our theoretical model and experimental data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PASP..125..838P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PASP..125..838P"><span id="translatedtitle">An Efficient and <span class="hlt">Optimal</span> <span class="hlt">Filter</span> for Identifying Point Sources in Millimeter/Submillimeter Wavelength Sky Maps</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Perera, T. A.; Wilson, G. W.; Scott, K. S.; Austermann, J. E.; Schaar, J. R.; Mancera, A.</p> <p>2013-07-01</p> <p>A new technique for reliably identifying point sources in millimeter/submillimeter wavelength maps is presented. This method accounts for the frequency dependence of noise in the Fourier domain as well as nonuniformities in the coverage of a field. This <span class="hlt">optimal</span> <span class="hlt">filter</span> is an improvement over commonly-used matched <span class="hlt">filters</span> that ignore coverage gradients. Treating noise variations in the Fourier domain as well as map space is traditionally viewed as a computationally intensive problem. We show that the penalty incurred in terms of computing time is quite small due to casting many of the calculations in terms of FFTs and exploiting the absence of sharp features in the noise spectra of observations. Practical aspects of implementing the <span class="hlt">optimal</span> <span class="hlt">filter</span> are presented in the context of data from the AzTEC bolometer camera. The advantages of using the new <span class="hlt">filter</span> over the standard matched <span class="hlt">filter</span> are also addressed in terms of a typical AzTEC map.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992agcp.agar.....A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992agcp.agar.....A"><span id="translatedtitle">Multivariable frequency response methods for <span class="hlt">optimal</span> Kalman-Bucy <span class="hlt">filters</span> with applications to radar tracking systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arcasoy, C. C.</p> <p>1992-11-01</p> <p>The problem of multi-output, infinite-time, linear time-invariant <span class="hlt">optimal</span> Kalman-Bucy <span class="hlt">filter</span> both in continuous and discrete-time cases in frequency domain is addressed. A simple new algorithm is given for the analytical solution to the steady-state gain of the optimum <span class="hlt">filter</span> based on a transfer function approach. The algorithm is based on spectral factorization of observed spectral density matrix of the <span class="hlt">filter</span> which generates directly the return-difference matrix of the <span class="hlt">optimal</span> <span class="hlt">filter</span>. The method is more direct than by algebraic Riccati equation solution and can easily be implemented on digital computer. The design procedure is illustrated by examples and closed-form solution of ECV and ECA radar tracking <span class="hlt">filters</span> are considered as an application of the method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19820033301&hterms=track+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dtrack%2Bfield','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820033301&hterms=track+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dtrack%2Bfield"><span id="translatedtitle">An <span class="hlt">optimal</span> numerical <span class="hlt">filter</span> for wide-field-of-view measurements of earth-emitted radiation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, G. L.; House, F. B.</p> <p>1981-01-01</p> <p>A technique is described in which all data points along an arc of the orbit may be used in an <span class="hlt">optimal</span> numerical <span class="hlt">filter</span> for wide-field-of-view measurements of earth emitted radiation. The statistical <span class="hlt">filter</span> design is derived whereby the <span class="hlt">filter</span> is required to give a minimum variance estimate of the radiative exitance at discrete points along the ground track of the satellite. An equation for the <span class="hlt">optimal</span> numerical <span class="hlt">filter</span> is given by minimizing the estimate error variance equation with respect to the <span class="hlt">filter</span> weights, resulting in a discrete form of the Wiener-Hopf equation. Finally, variances of the errors in the radiant exitance can be computed along the ground track and in the cross track directions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4732035','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4732035"><span id="translatedtitle">Damage Detection in Flexible Plates through Reduced-Order Modeling and Hybrid <span class="hlt">Particle</span>-Kalman <span class="hlt">Filtering</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Capellari, Giovanni; Eftekhar Azam, Saeed; Mariani, Stefano</p> <p>2015-01-01</p> <p>Health monitoring of lightweight structures, like thin flexible plates, is of interest in several engineering fields. In this paper, a recursive Bayesian procedure is proposed to monitor the health of such structures through data collected by a network of <span class="hlt">optimally</span> placed inertial sensors. As a main drawback of standard monitoring procedures is linked to the computational costs, two remedies are jointly considered: first, an order-reduction of the numerical model used to track the structural dynamics, enforced with proper orthogonal decomposition; and, second, an improved <span class="hlt">particle</span> <span class="hlt">filter</span>, which features an extended Kalman updating of each evolving <span class="hlt">particle</span> before the resampling stage. The former remedy can reduce the number of effective degrees-of-freedom of the structural model to a few only (depending on the excitation), whereas the latter one allows to track the evolution of damage and to locate it thanks to an intricate formulation. To assess the effectiveness of the proposed procedure, the case of a plate subject to bending is investigated; it is shown that, when the procedure is appropriately fed by measurements, damage is efficiently and accurately estimated. PMID:26703615</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26703615','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26703615"><span id="translatedtitle">Damage Detection in Flexible Plates through Reduced-Order Modeling and Hybrid <span class="hlt">Particle</span>-Kalman <span class="hlt">Filtering</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Capellari, Giovanni; Azam, Saeed Eftekhar; Mariani, Stefano</p> <p>2015-01-01</p> <p>Health monitoring of lightweight structures, like thin flexible plates, is of interest in several engineering fields. In this paper, a recursive Bayesian procedure is proposed to monitor the health of such structures through data collected by a network of <span class="hlt">optimally</span> placed inertial sensors. As a main drawback of standard monitoring procedures is linked to the computational costs, two remedies are jointly considered: first, an order-reduction of the numerical model used to track the structural dynamics, enforced with proper orthogonal decomposition; and, second, an improved <span class="hlt">particle</span> <span class="hlt">filter</span>, which features an extended Kalman updating of each evolving <span class="hlt">particle</span> before the resampling stage. The former remedy can reduce the number of effective degrees-of-freedom of the structural model to a few only (depending on the excitation), whereas the latter one allows to track the evolution of damage and to locate it thanks to an intricate formulation. To assess the effectiveness of the proposed procedure, the case of a plate subject to bending is investigated; it is shown that, when the procedure is appropriately fed by measurements, damage is efficiently and accurately estimated. PMID:26703615</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=30455&keyword=dry+AND+cleaner&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=50477719&CFTOKEN=13978409','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=30455&keyword=dry+AND+cleaner&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=50477719&CFTOKEN=13978409"><span id="translatedtitle">AIR <span class="hlt">FILTER</span> <span class="hlt">PARTICLE</span>-SIZE EFFICIENCY TESTING FOR DIAMETERS GREATER THAN 1UM</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The paper discusses tests of air <span class="hlt">filter</span> <span class="hlt">particle</span>-size efficiency for diameters greater than 1 micrometer. valuation of air cleaner efficiencies in this size range can be quite demanding, depending on the required accuracy. uch <span class="hlt">particles</span> have sufficient mass to require considerati...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013RScI...84f5109C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013RScI...84f5109C"><span id="translatedtitle">Object detection and tracking with active camera on motion vectors of feature points and <span class="hlt">particle</span> <span class="hlt">filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Yong; Zhang, Rong-Hua; Shang, Lei; Hu, Eric</p> <p>2013-06-01</p> <p>A method based on motion vectors of feature points and <span class="hlt">particle</span> <span class="hlt">filter</span> has been proposed and developed for an active/moving camera for object detection and tracking purposes. The object is detected by histogram of motion vectors first, and then, on the basis of <span class="hlt">particle</span> <span class="hlt">filter</span> algorithm, the weighing factors are obtained via color information. In addition, re-sampling strategy and surf feature points are used to remedy the drawback of <span class="hlt">particle</span> degeneration. Experimental results demonstrate the practicability and accuracy of the new method and are presented in the paper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23822380','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23822380"><span id="translatedtitle">Object detection and tracking with active camera on motion vectors of feature points and <span class="hlt">particle</span> <span class="hlt">filter</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Yong; Zhang, Rong-Hua; Shang, Lei; Hu, Eric</p> <p>2013-06-01</p> <p>A method based on motion vectors of feature points and <span class="hlt">particle</span> <span class="hlt">filter</span> has been proposed and developed for an active∕moving camera for object detection and tracking purposes. The object is detected by histogram of motion vectors first, and then, on the basis of <span class="hlt">particle</span> <span class="hlt">filter</span> algorithm, the weighing factors are obtained via color information. In addition, re-sampling strategy and surf feature points are used to remedy the drawback of <span class="hlt">particle</span> degeneration. Experimental results demonstrate the practicability and accuracy of the new method and are presented in the paper. PMID:23822380</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/827943','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/827943"><span id="translatedtitle"><span class="hlt">Optimized</span> Loading for <span class="hlt">Particle</span>-in-cell Gyrokinetic Simulations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>J.L.V. Lewandowski</p> <p>2004-05-13</p> <p>The problem of <span class="hlt">particle</span> loading in <span class="hlt">particle</span>-in-cell gyrokinetic simulations is addressed using a quadratic <span class="hlt">optimization</span> algorithm. <span class="hlt">Optimized</span> loading in configuration space dramatically reduces the short wavelength modes in the electrostatic potential that are partly responsible for the non-conservation of total energy; further, the long wavelength modes are resolved with good accuracy. As a result, the conservation of energy for the <span class="hlt">optimized</span> loading is much better that the conservation of energy for the random loading. The method is valid for any geometry and can be coupled to <span class="hlt">optimization</span> algorithms in velocity space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4335141','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4335141"><span id="translatedtitle">Chaotic <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> with Mutation for Classification</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Assarzadeh, Zahra; Naghsh-Nilchi, Ahmad Reza</p> <p>2015-01-01</p> <p>In this paper, a chaotic <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> with mutation-based classifier <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> is proposed to classify patterns of different classes in the feature space. The introduced mutation operators and chaotic sequences allows us to overcome the problem of early convergence into a local minima associated with <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> algorithms. That is, the mutation operator sharpens the convergence and it tunes the best possible solution. Furthermore, to remove the irrelevant data and reduce the dimensionality of medical datasets, a feature selection approach using binary version of the proposed <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> is introduced. In order to demonstrate the effectiveness of our proposed classifier, mutation-based classifier <span class="hlt">particle</span> swarm <span class="hlt">optimization</span>, it is checked out with three sets of data classifications namely, Wisconsin diagnostic breast cancer, Wisconsin breast cancer and heart-statlog, with different feature vector dimensions. The proposed algorithm is compared with different classifier algorithms including k-nearest neighbor, as a conventional classifier, <span class="hlt">particle</span> swarm-classifier, genetic algorithm, and Imperialist competitive algorithm-classifier, as more sophisticated ones. The performance of each classifier was evaluated by calculating the accuracy, sensitivity, specificity and Matthews's correlation coefficient. The experimental results show that the mutation-based classifier <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> unequivocally performs better than all the compared algorithms. PMID:25709937</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25709937','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25709937"><span id="translatedtitle">Chaotic <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> with mutation for classification.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Assarzadeh, Zahra; Naghsh-Nilchi, Ahmad Reza</p> <p>2015-01-01</p> <p>In this paper, a chaotic <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> with mutation-based classifier <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> is proposed to classify patterns of different classes in the feature space. The introduced mutation operators and chaotic sequences allows us to overcome the problem of early convergence into a local minima associated with <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> algorithms. That is, the mutation operator sharpens the convergence and it tunes the best possible solution. Furthermore, to remove the irrelevant data and reduce the dimensionality of medical datasets, a feature selection approach using binary version of the proposed <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> is introduced. In order to demonstrate the effectiveness of our proposed classifier, mutation-based classifier <span class="hlt">particle</span> swarm <span class="hlt">optimization</span>, it is checked out with three sets of data classifications namely, Wisconsin diagnostic breast cancer, Wisconsin breast cancer and heart-statlog, with different feature vector dimensions. The proposed algorithm is compared with different classifier algorithms including k-nearest neighbor, as a conventional classifier, <span class="hlt">particle</span> swarm-classifier, genetic algorithm, and Imperialist competitive algorithm-classifier, as more sophisticated ones. The performance of each classifier was evaluated by calculating the accuracy, sensitivity, specificity and Matthews's correlation coefficient. The experimental results show that the mutation-based classifier <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> unequivocally performs better than all the compared algorithms. PMID:25709937</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10148667','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10148667"><span id="translatedtitle">Linear adaptive noise-reduction <span class="hlt">filters</span> for tomographic imaging: <span class="hlt">Optimizing</span> for minimum mean square error</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sun, W Y</p> <p>1993-04-01</p> <p>This thesis solves the problem of finding the <span class="hlt">optimal</span> linear noise-reduction <span class="hlt">filter</span> for linear tomographic image reconstruction. The <span class="hlt">optimization</span> is data dependent and results in minimizing the mean-square error of the reconstructed image. The error is defined as the difference between the result and the best possible reconstruction. Applications for the <span class="hlt">optimal</span> <span class="hlt">filter</span> include reconstructions of positron emission tomographic (PET), X-ray computed tomographic, single-photon emission tomographic, and nuclear magnetic resonance imaging. Using high resolution PET as an example, the <span class="hlt">optimal</span> <span class="hlt">filter</span> is derived and presented for the convolution backprojection, Moore-Penrose pseudoinverse, and the natural-pixel basis set reconstruction methods. Simulations and experimental results are presented for the convolution backprojection method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EJASP2015...33R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EJASP2015...33R"><span id="translatedtitle">Kalman <span class="hlt">filter</span> with a linear state model for PDR+WLAN positioning and its application to assisting a <span class="hlt">particle</span> <span class="hlt">filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Raitoharju, Matti; Nurminen, Henri; Piché, Robert</p> <p>2015-12-01</p> <p>Indoor positioning based on wireless local area network (WLAN) signals is often enhanced using pedestrian dead reckoning (PDR) based on an inertial measurement unit. The state evolution model in PDR is usually nonlinear. We present a new linear state evolution model for PDR. In simulated-data and real-data tests of tightly coupled WLAN-PDR positioning, the positioning accuracy with this linear model is better than with the traditional models when the initial heading is not known, which is a common situation. The proposed method is computationally light and is also suitable for smoothing. Furthermore, we present modifications to WLAN positioning based on Gaussian coverage areas and show how a Kalman <span class="hlt">filter</span> using the proposed model can be used for integrity monitoring and (re)initialization of a <span class="hlt">particle</span> <span class="hlt">filter</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18477653','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18477653"><span id="translatedtitle"><span class="hlt">Filter</span> performance of n99 and n95 facepiece respirators against viruses and ultrafine <span class="hlt">particles</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Eninger, Robert M; Honda, Takeshi; Adhikari, Atin; Heinonen-Tanski, Helvi; Reponen, Tiina; Grinshpun, Sergey A</p> <p>2008-07-01</p> <p>The performance of three <span class="hlt">filtering</span> facepiece respirators (two models of N99 and one N95) challenged with an inert aerosol (NaCl) and three virus aerosols (enterobacteriophages MS2 and T4 and Bacillus subtilis phage)-all with significant ultrafine components-was examined using a manikin-based protocol with respirators sealed on manikins. Three inhalation flow rates, 30, 85, and 150 l min(-1), were tested. The <span class="hlt">filter</span> penetration and the quality factor were determined. Between-respirator and within-respirator comparisons of penetration values were performed. At the most penetrating <span class="hlt">particle</span> size (MPPS), >3% of MS2 virions penetrated through <span class="hlt">filters</span> of both N99 models at an inhalation flow rate of 85 l min(-1). Inhalation airflow had a significant effect upon <span class="hlt">particle</span> penetration through the tested respirator <span class="hlt">filters</span>. The <span class="hlt">filter</span> quality factor was found suitable for making relative performance comparisons. The MPPS for challenge aerosols was <0.1 mum in electrical mobility diameter for all tested respirators. Mean <span class="hlt">particle</span> penetration (by count) was significantly increased when the size fraction of <0.1 mum was included as compared to <span class="hlt">particles</span> >0.1 mum. The filtration performance of the N95 respirator approached that of the two models of N99 over the range of <span class="hlt">particle</span> sizes tested ( approximately 0.02 to 0.5 mum). <span class="hlt">Filter</span> penetration of the tested biological aerosols did not exceed that of inert NaCl aerosol. The results suggest that inert NaCl aerosols may generally be appropriate for modeling <span class="hlt">filter</span> penetration of similarly sized virions. PMID:18477653</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/678948','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/678948"><span id="translatedtitle">Loss of <span class="hlt">particle</span> nitrate from Teflon sampling <span class="hlt">filters</span>: Effects on measured gravimetric mass. Final report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ashbaugh, L.L.; Eldred, R.A.</p> <p>1998-09-01</p> <p>The report describes analysis of three data sets to evaluate the extent of mass loss on Teflon <span class="hlt">filters</span> due to ammonium nitrate volatilization. The effect on measured mass is site-dependent, and depends on the meteorological conditions and the fraction of PM-10 mass that consists of ammonium nitrate <span class="hlt">particles</span>. The highest mass loss found in the California Acid Deposition Monitoring Program network occurred during summer daytime in southern California, amounting to 30-50% of the gravimetric mass. The biased mass measurement implies that the Federal Reference Method sampler for fine <span class="hlt">particles</span> may lead to control strategies that are biased toward sources of fugitive dust and other primary <span class="hlt">particle</span> emission sources. This analysis also has implications for the speciation monitoring methods being considered by the EPA. Samples must be collected on nylon <span class="hlt">filters</span> for nitrate analysis, and on Teflon and quartz <span class="hlt">filters</span> for analysis of mass, elements, and carbon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25227085','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25227085"><span id="translatedtitle">Bandwidth <span class="hlt">optimization</span> for <span class="hlt">filter</span>-based fatigue index in different inter-electrode distances.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, Jungyoon; Son, Jongsang; Kim, Youngho</p> <p>2014-01-01</p> <p>In this study, the bandwidth of the <span class="hlt">filter</span>-based fatigue index was determined by the comparison of <span class="hlt">optimized</span> cut-off frequencies in different inter-electrode distances. Sixty-one subjects participated in isometric knee extension, isotonic ankle dorsiflexion, and isotonic elbow extension exercises. Electromyography (EMG) signals were obtained from right rectus femoris, triceps brachii, and tibialis anterior muscles during exercises. The <span class="hlt">filter</span>-based fatigue index was compared with mean root-mean-square values, median frequency, Dimitrov spectral index, and Gonzalez-Izal wavelet index. <span class="hlt">Optimized</span> cut-off frequencies of the high-pass <span class="hlt">filter</span> for three different exercises and three different inter-electrode distances were about 350 Hz. Results from this study support that around 350 Hz high-pass <span class="hlt">filter</span> could be useful to determine cut-off frequency for fatigue prediction in general purposes. PMID:25227085</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008SPIE.6968E..05P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008SPIE.6968E..05P"><span id="translatedtitle">A <span class="hlt">particle-filtering</span> approach to convoy tracking in the midst of civilian traffic</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pollard, Evangeline; Pannetier, Benjamin; Rombaut, Michèle</p> <p>2008-04-01</p> <p>In the battlefield surveillance domain, ground target tracking is used to evaluate the threat. Data used for tracking is given by a Ground Moving Target Indicator (GMTI) sensor which only detects moving targets. Multiple target tracking has been widely studied but most of the algorithms have weaknesses when targets are close together, as they are in a convoy. In this work, we propose a <span class="hlt">filtering</span> approach for convoys in the midst of civilian traffic. Inspired by <span class="hlt">particle</span> <span class="hlt">filtering</span>, our specific algorithm cannot be applied to all the targets because of its complexity. That is why well discriminated targets are tracked using an Interacting Multiple Model-Multiple Hypothesis Tracking (IMM-MHT), whereas the convoy targets are tracked with a specific <span class="hlt">particle</span> <span class="hlt">filter</span>. We make the assumption that the convoy is detected (position and number of targets). Our approach is based on an Independent Partition <span class="hlt">Particle</span> <span class="hlt">Filter</span> (IPPF) incorporating constraint-regions. The originality of our approach is to consider a velocity constraint (all the vehicles belonging to the convoy have the same velocity) and a group constraint. Consequently, the multitarget state vector contains all the positions of the individual targets and a single convoy velocity vector. When another target is detected crossing or overtaking the convoy, a specific algorithm is used and the non-cooperative target is tracked down an adapted <span class="hlt">particle</span> <span class="hlt">filter</span>. As demonstrated by our simulations, a high increase in convoy tracking performance is obtained with our approach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4610564','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4610564"><span id="translatedtitle">RB <span class="hlt">Particle</span> <span class="hlt">Filter</span> Time Synchronization Algorithm Based on the DPM Model</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Guo, Chunsheng; Shen, Jia; Sun, Yao; Ying, Na</p> <p>2015-01-01</p> <p>Time synchronization is essential for node localization, target tracking, data fusion, and various other Wireless Sensor Network (WSN) applications. To improve the estimation accuracy of continuous clock offset and skew of mobile nodes in WSNs, we propose a novel time synchronization algorithm, the Rao-Blackwellised (RB) <span class="hlt">particle</span> <span class="hlt">filter</span> time synchronization algorithm based on the Dirichlet process mixture (DPM) model. In a state-space equation with a linear substructure, state variables are divided into linear and non-linear variables by the RB <span class="hlt">particle</span> <span class="hlt">filter</span> algorithm. These two variables can be estimated using Kalman <span class="hlt">filter</span> and <span class="hlt">particle</span> <span class="hlt">filter</span>, respectively, which improves the computational efficiency more so than if only the <span class="hlt">particle</span> <span class="hlt">filter</span> was used. In addition, the DPM model is used to describe the distribution of non-deterministic delays and to automatically adjust the number of Gaussian mixture model components based on the observational data. This improves the estimation accuracy of clock offset and skew, which allows achieving the time synchronization. The time synchronization performance of this algorithm is also validated by computer simulations and experimental measurements. The results show that the proposed algorithm has a higher time synchronization precision than traditional time synchronization algorithms. PMID:26404291</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4102095','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4102095"><span id="translatedtitle"><span class="hlt">Particle</span> <span class="hlt">Filtering</span> for Obstacle Tracking in UAS Sense and Avoid Applications</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Moccia, Antonio</p> <p>2014-01-01</p> <p>Obstacle detection and tracking is a key function for UAS sense and avoid applications. In fact, obstacles in the flight path must be detected and tracked in an accurate and timely manner in order to execute a collision avoidance maneuver in case of collision threat. The most important parameter for the assessment of a collision risk is the Distance at Closest Point of Approach, that is, the predicted minimum distance between own aircraft and intruder for assigned current position and speed. Since assessed methodologies can cause some loss of accuracy due to nonlinearities, advanced <span class="hlt">filtering</span> methodologies, such as <span class="hlt">particle</span> <span class="hlt">filters</span>, can provide more accurate estimates of the target state in case of nonlinear problems, thus improving system performance in terms of collision risk estimation. The paper focuses on algorithm development and performance evaluation for an obstacle tracking system based on a <span class="hlt">particle</span> <span class="hlt">filter</span>. The <span class="hlt">particle</span> <span class="hlt">filter</span> algorithm was tested in off-line simulations based on data gathered during flight tests. In particular, radar-based tracking was considered in order to evaluate the impact of <span class="hlt">particle</span> <span class="hlt">filtering</span> in a single sensor framework. The analysis shows some accuracy improvements in the estimation of Distance at Closest Point of Approach, thus reducing the delay in collision detection. PMID:25105154</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25105154','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25105154"><span id="translatedtitle"><span class="hlt">Particle</span> <span class="hlt">filtering</span> for obstacle tracking in UAS sense and avoid applications.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tirri, Anna Elena; Fasano, Giancarmine; Accardo, Domenico; Moccia, Antonio</p> <p>2014-01-01</p> <p>Obstacle detection and tracking is a key function for UAS sense and avoid applications. In fact, obstacles in the flight path must be detected and tracked in an accurate and timely manner in order to execute a collision avoidance maneuver in case of collision threat. The most important parameter for the assessment of a collision risk is the Distance at Closest Point of Approach, that is, the predicted minimum distance between own aircraft and intruder for assigned current position and speed. Since assessed methodologies can cause some loss of accuracy due to nonlinearities, advanced <span class="hlt">filtering</span> methodologies, such as <span class="hlt">particle</span> <span class="hlt">filters</span>, can provide more accurate estimates of the target state in case of nonlinear problems, thus improving system performance in terms of collision risk estimation. The paper focuses on algorithm development and performance evaluation for an obstacle tracking system based on a <span class="hlt">particle</span> <span class="hlt">filter</span>. The <span class="hlt">particle</span> <span class="hlt">filter</span> algorithm was tested in off-line simulations based on data gathered during flight tests. In particular, radar-based tracking was considered in order to evaluate the impact of <span class="hlt">particle</span> <span class="hlt">filtering</span> in a single sensor framework. The analysis shows some accuracy improvements in the estimation of Distance at Closest Point of Approach, thus reducing the delay in collision detection. PMID:25105154</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19963573','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19963573"><span id="translatedtitle">An <span class="hlt">optimal</span> spatial <span class="hlt">filtering</span> electrode for brain computer interface.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Besio, W G; Kay, S M; Liu, X</p> <p>2009-01-01</p> <p>There are millions of people in the U.S. and many more worldwide who could benefit from a noninvasive-based electroencephalography (EEG) brain computer interface (BCI). A BCI is an alternative or augmentative communication method for people with severe motor disabilities. However, EEG suffers from poor spatial resolution and signal-to-noise ratio (SNR). To improve the spatial resolution and SNR many researchers have turned to implantable electrodes. We have previously reported on significant improvements in BCI recognition rates using tripolar concentric ring electrodes compared to disc electrodes. We now report on a <span class="hlt">optimal</span> method for combining the outputs from the independent elements of the tripolar concentric ring electrodes to improve the spatial resolution further. We used minimum variance distortionless look (MVDL), a beamformer, on simulated data to compare the spatial sensitivity of the <span class="hlt">optimal</span> combination to disc electrodes and the tripolar concentric ring electrode surface Laplacian. The <span class="hlt">optimal</span> combination shows the highest spatial sensitivity with the Laplacian a close second and disc electrodes resulting in a distant third. Further analysis is necessary with a more realistic computer model and then real signals. however it appears that the <span class="hlt">optimal</span> combination may improve the spatial resolution of EEG further which in turn can be utilized to improve noninvasive EEG-based BCIs. PMID:19963573</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012OptEn..51d7203L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012OptEn..51d7203L"><span id="translatedtitle">Feature-driven motion model-based <span class="hlt">particle-filter</span> tracking method with abrupt motion handling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Yu; Lai, Shiming; Wang, Bin; Zhang, Maojun; Wang, Wei</p> <p>2012-04-01</p> <p>The potential for the research of object tracking in computer vision has been well established, but previous object-tracking methods, which consider only continuous and smooth motion, are limited in handling abrupt motions. We introduce an efficient algorithm to tackle this limitation. A feature-driven (FD) motion model-based features from accelerated segment test (FAST) feature matching is proposed in the <span class="hlt">particle-filtering</span> framework. Various evaluations have demonstrated that this motion model can improve existing methods' performances to handle abrupt motion significantly. The proposed model can be applied to most existing <span class="hlt">particle-filter</span> tracking methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005SPIE.6042E..3SK','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005SPIE.6042E..3SK"><span id="translatedtitle">Person tracking with a mobile robot using <span class="hlt">particle</span> <span class="hlt">filters</span> in complex environment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kwon, Ho Sang; Kim, Young Joong; Lim, Myo Taeg</p> <p>2005-12-01</p> <p>Based on a <span class="hlt">particle</span> <span class="hlt">filter</span>, a method that mobile robots can track a person in complex environment was presented. The problem of person following for mobile robot has been researched many different areas. The main issues of following a person are real time constraint, motion change of person during the tracking and occlusion with other objects. Using appearance-adaptive models in a <span class="hlt">particle</span> <span class="hlt">filter</span>, a robust visual tracking algorithm was realized. The appearance-adaptive model can handle occlusion with other people while the target is moving.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ChPhB..22c0505L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ChPhB..22c0505L"><span id="translatedtitle">Hybrid three-dimensional variation and <span class="hlt">particle</span> <span class="hlt">filtering</span> for nonlinear systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leng, Hong-Ze; Song, Jun-Qiang</p> <p>2013-03-01</p> <p>This work addresses the problem of estimating the states of nonlinear dynamic systems with sparse observations. We present a hybrid three-dimensional variation (3DVar) and <span class="hlt">particle</span> piltering (PF) method, which combines the advantages of 3DVar and <span class="hlt">particle</span>-based <span class="hlt">filters</span>. By minimizing the cost function, this approach will produce a better proposal distribution of the state. Afterwards the stochastic resampling step in standard PF can be avoided through a deterministic scheme. The simulation results show that the performance of the new method is superior to the traditional ensemble Kalman <span class="hlt">filtering</span> (EnKF) and the standard PF, especially in highly nonlinear systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22717094','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22717094"><span id="translatedtitle">Improvements of Adaptive <span class="hlt">Filtering</span> by <span class="hlt">Optimal</span> Projection to <span class="hlt">filter</span> different artifact types on long duration EEG recordings.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Boudet, S; Peyrodie, L; Forzy, G; Pinti, A; Toumi, H; Gallois, P</p> <p>2012-10-01</p> <p>Adaptive <span class="hlt">Filtering</span> by <span class="hlt">Optimal</span> Projection (AFOP) is an automatic method for reducing ocular and muscular artifacts on electro-encephalographic (EEG) recordings. This paper presents two additions to this method: an improvement of the stability of ocular artifact <span class="hlt">filtering</span> and an adaptation of the method for <span class="hlt">filtering</span> electrode artifacts. With these improvements, it is possible to reduce almost all the current types of artifacts, while preserving brain signals, particularly those characterising epilepsy. This generalised method consists of dividing the signal into several time-frequency windows, and in applying different spatial <span class="hlt">filters</span> to each. Two steps are required to define one of these spatial <span class="hlt">filters</span>: the first step consists of defining artifact spatial projection using the Common Spatial Pattern (CSP) method and the second consists of defining EEG spatial projection via regression. For this second step, a progressive orthogonalisation process is proposed to improve stability. This method has been tested on long-duration EEG recordings of epileptic patients. A neurologist quantified the ratio of removed artifacts and the ratio of preserved EEG. Among the 330 artifacted pages used for evaluation, readability was judged better for 78% of pages, equal for 20% of pages, and worse for 2%. Artifact amplitudes were reduced by 80% on average. At the same time, brain sources were preserved in amplitude from 70% to 95% depending on the type of waves (alpha, theta, delta, spikes, etc.). A blind comparison with manual Independent Component Analysis (ICA) was also realised. The results show that this method is competitive and useful for routine clinical practice. PMID:22717094</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19746797','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19746797"><span id="translatedtitle">Spectral <span class="hlt">optimization</span> for measuring electron density by the dual-energy computed tomography coupled with balanced <span class="hlt">filter</span> method.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Saito, Masatoshi</p> <p>2009-08-01</p> <p>Dual-energy computed tomography (DECT) has the potential for measuring electron density distribution in a human body to predict the range of <span class="hlt">particle</span> beams for treatment planning in proton or heavy-ion radiotherapy. However, thus far, a practical dual-energy method that can be used to precisely determine electron density for treatment planning in <span class="hlt">particle</span> radiotherapy has not been developed. In this article, another DECT technique involving a balanced <span class="hlt">filter</span> method using a conventional x-ray tube is described. For the spectral <span class="hlt">optimization</span> of DECT using balanced <span class="hlt">filters</span>, the author calculates beam-hardening error and air kerma required to achieve a desired noise level in electron density and effective atomic number images of a cylindrical water phantom with 50 cm diameter. The calculation enables the selection of beam parameters such as tube voltage, balanced <span class="hlt">filter</span> material, and its thickness. The <span class="hlt">optimized</span> parameters were applied to cases with different phantom diameters ranging from 5 to 50 cm for the calculations. The author predicts that the <span class="hlt">optimal</span> combination of tube voltages would be 80 and 140 kV with Tb/Hf and Bi/Mo <span class="hlt">filter</span> pairs for the 50-cm-diameter water phantom. When a single phantom calibration at a diameter of 25 cm was employed to cover all phantom sizes, maximum absolute beam-hardening errors were 0.3% and 0.03% for electron density and effective atomic number, respectively, over a range of diameters of the water phantom. The beam-hardening errors were 1/10 or less as compared to those obtained by conventional DECT, although the dose was twice that of the conventional DECT case. From the viewpoint of beam hardening and the tube-loading efficiency, the present DECT using balanced <span class="hlt">filters</span> would be significantly more effective in measuring the electron density than the conventional DECT. Nevertheless, further developments of low-exposure imaging technology should be necessary as well as x-ray tubes with higher outputs to apply DECT coupled with the balanced <span class="hlt">filter</span> method for clinical use. PMID:19746797</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20080048261&hterms=jang&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Djang','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20080048261&hterms=jang&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Djang"><span id="translatedtitle">Ares-I Bending <span class="hlt">Filter</span> Design using a Constrained <span class="hlt">Optimization</span> Approach</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hall, Charles; Jang, Jiann-Woei; Hall, Robert; Bedrossian, Nazareth</p> <p>2008-01-01</p> <p>The Ares-I launch vehicle represents a challenging flex-body structural environment for control system design. Software <span class="hlt">filtering</span> of the inertial sensor output is required to ensure adequate stable response to guidance commands while minimizing trajectory deviations. This paper presents a design methodology employing numerical <span class="hlt">optimization</span> to develop the Ares-I bending <span class="hlt">filters</span>. The design objectives include attitude tracking accuracy and robust stability with respect to rigid body dynamics, propellant slosh, and flex. Under the assumption that the Ares-I time-varying dynamics and control system can be frozen over a short period of time, the bending <span class="hlt">filters</span> are designed to stabilize all the selected frozen-time launch control systems in the presence of parameter uncertainty. To ensure adequate response to guidance command, step response specifications are introduced as constraints in the <span class="hlt">optimization</span> problem. Imposing these constrains minimizes performance degradation caused by the addition of the bending <span class="hlt">filters</span>. The first stage bending <span class="hlt">filter</span> design achieves stability by adding lag to the first structural frequency to phase stabilize the first flex mode while gain stabilizing the higher modes. The upper stage bending <span class="hlt">filter</span> design gain stabilizes all the flex bending modes. The bending <span class="hlt">filter</span> designs provided here have been demonstrated to provide stable first and second stage control systems in both Draper Ares Stability Analysis Tool (ASAT) and the MSFC MAVERIC 6DOF nonlinear time domain simulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9654E..0BP','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9654E..0BP"><span id="translatedtitle">Design and <span class="hlt">optimization</span> of high reflectance graded index optical <span class="hlt">filter</span> with quintic apodization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Praveen Kumar, Vemuri S. R. S.; Sunita, Parinam; Kumar, Mukesh; Rao, Parinam Krishna; Kumari, Neelam; Karar, Vinod; Sharma, Amit L.</p> <p>2015-06-01</p> <p>Rugate <span class="hlt">filters</span> are a special kind of graded-index films that may provide advantages in both, optical performance and mechanical properties of the optical coatings. In this work, design and <span class="hlt">optimization</span> of a high reflection rugate <span class="hlt">filter</span> having reflection peak at 540nm has been presented which has been further <span class="hlt">optimized</span> for side-lobe suppression. A suitable number of apodization and matching layers, generated through Quintic function, were added to the basic sinusoidal refractive index profile to achieve high reflectance of around 80% in the rejection window for normal incidence. Smaller index contrast between successive layers in the present design leads to less residual stress in the thinfilm stack which enhances the adhesion and mechanical strength of the <span class="hlt">filter</span>. The <span class="hlt">optimized</span> results show excellent side lobe suppression achieved around the stopband.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/837305','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/837305"><span id="translatedtitle">Removal of <span class="hlt">Particles</span> and Acid Gases (SO2 or HCl) with a Ceramic <span class="hlt">Filter</span> by Addition of Dry Sorbents</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hemmer, G.; Kasper, G.; Wang, J.; Schaub, G.</p> <p>2002-09-20</p> <p>The present investigation intends to add to the fundamental process design know-how for dry flue gas cleaning, especially with respect to process flexibility, in cases where variations in the type of fuel and thus in concentration of contaminants in the flue gas require <span class="hlt">optimization</span> of operating conditions. In particular, temperature effects of the physical and chemical processes occurring simultaneously in the gas-<span class="hlt">particle</span> dispersion and in the <span class="hlt">filter</span> cake/<span class="hlt">filter</span> medium are investigated in order to improve the predictive capabilities for identifying optimum operating conditions. Sodium bicarbonate (NaHCO{sub 3}) and calcium hydroxide (Ca(OH){sub 2}) are known as efficient sorbents for neutralizing acid flue gas components such as HCl, HF, and SO{sub 2}. According to their physical properties (e.g. porosity, pore size) and chemical behavior (e.g. thermal decomposition, reactivity for gas-solid reactions), optimum conditions for their application vary widely. The results presented concentrate on the development of quantitative data for filtration stability and overall removal efficiency as affected by operating temperature. Experiments were performed in a small pilot unit with a ceramic <span class="hlt">filter</span> disk of the type Dia-Schumalith 10-20 (Fig. 1, described in more detail in Hemmer 2002 and Hemmer et al. 1999), using model flue gases containing SO{sub 2} and HCl, flyash from wood bark combustion, and NaHCO{sub 3} as well as Ca(OH){sub 2} as sorbent material (<span class="hlt">particle</span> size d{sub 50}/d{sub 84} : 35/192 {micro}m, and 3.5/16, respectively). The pilot unit consists of an entrained flow reactor (gas duct) representing the raw gas volume of a <span class="hlt">filter</span> house and the <span class="hlt">filter</span> disk with a <span class="hlt">filter</span> cake, operating continuously, simulating <span class="hlt">filter</span> cake build-up and cleaning of the <span class="hlt">filter</span> medium by jet pulse. Temperatures varied from 200 to 600 C, sorbent stoichiometric ratios from zero to 2, inlet concentrations were on the order of 500 to 700 mg/m{sup 3}, water vapor contents ranged from zero to 20 vol%. The experimental program with NaHCO{sub 3} is listed in Table 1. In addition, model calculations were carried out based on own and published experimental results that estimate residence time and temperature effects on removal efficiencies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010IEITI..91.1963Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010IEITI..91.1963Y"><span id="translatedtitle">Quantum-Behaved <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> with Chaotic Search</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Kaiqiao; Nomura, Hirosato</p> <p></p> <p>The chaotic search is introduced into Quantum-behaved <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (QPSO) to increase the diversity of the swarm in the latter period of the search, so as to help the system escape from local optima. Taking full advantages of the characteristics of ergodicity and randomicity of chaotic variables, the chaotic search is carried out in the neighborhoods of the <span class="hlt">particles</span> which are trapped into local optima. The experimental results on test functions show that QPSO with chaotic search outperforms the <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) and QPSO.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17278557','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17278557"><span id="translatedtitle">A multiobjective memetic algorithm based on <span class="hlt">particle</span> swarm <span class="hlt">optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Dasheng; Tan, K C; Goh, C K; Ho, W K</p> <p>2007-02-01</p> <p>In this paper, a new memetic algorithm (MA) for multiobjective (MO) <span class="hlt">optimization</span> is proposed, which combines the global search ability of <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> with a synchronous local search heuristic for directed local fine-tuning. A new <span class="hlt">particle</span> updating strategy is proposed based upon the concept of fuzzy global-best to deal with the problem of premature convergence and diversity maintenance within the swarm. The proposed features are examined to show their individual and combined effects in MO <span class="hlt">optimization</span>. The comparative study shows the effectiveness of the proposed MA, which produces solution sets that are highly competitive in terms of convergence, diversity, and distribution. PMID:17278557</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15603077','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15603077"><span id="translatedtitle">Two-stage hybrid <span class="hlt">optimization</span> of fiber Bragg gratings for design of linear phase <span class="hlt">filters</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zheng, Rui Tao; Ngo, Nam Quoc; Le Binh, Nguyen; Tjin, Swee Chuan</p> <p>2004-12-01</p> <p>We present a new hybrid <span class="hlt">optimization</span> method for the synthesis of fiber Bragg gratings (FBGs) with complex characteristics. The hybrid <span class="hlt">optimization</span> method is a two-tier search that employs a global <span class="hlt">optimization</span> algorithm [i.e., the tabu search (TS) algorithm] and a local <span class="hlt">optimization</span> method (i.e., the quasi-Netwon method). First the TS global <span class="hlt">optimization</span> algorithm is used to find a "promising" FBG structure that has a spectral response as close as possible to the targeted spectral response. Then the quasi-Newton local <span class="hlt">optimization</span> method is applied to further <span class="hlt">optimize</span> the FBG structure obtained from the TS algorithm to arrive at a targeted spectral response. A dynamic mechanism for weighting of different requirements of the spectral response is employed to enhance the <span class="hlt">optimization</span> efficiency. To demonstrate the effectiveness of the method, the synthesis of three linear-phase optical <span class="hlt">filters</span> based on FBGs with different grating lengths is described. PMID:15603077</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhyD..298...21Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhyD..298...21Q"><span id="translatedtitle">Blended <span class="hlt">particle</span> methods with adaptive subspaces for <span class="hlt">filtering</span> turbulent dynamical systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qi, Di; Majda, Andrew J.</p> <p>2015-04-01</p> <p>It is a major challenge throughout science and engineering to improve uncertain model predictions by utilizing noisy data sets from nature. Hybrid methods combining the advantages of traditional <span class="hlt">particle</span> <span class="hlt">filters</span> and the Kalman <span class="hlt">filter</span> offer a promising direction for <span class="hlt">filtering</span> or data assimilation in high dimensional turbulent dynamical systems. In this paper, blended <span class="hlt">particle</span> <span class="hlt">filtering</span> methods that exploit the physical structure of turbulent dynamical systems are developed. Non-Gaussian features of the dynamical system are captured adaptively in an evolving-in-time low dimensional subspace through <span class="hlt">particle</span> methods, while at the same time statistics in the remaining portion of the phase space are amended by conditional Gaussian mixtures interacting with the <span class="hlt">particles</span>. The importance of both using the adaptively evolving subspace and introducing conditional Gaussian statistics in the orthogonal part is illustrated here by simple examples. For practical implementation of the algorithms, finding the most probable distributions that characterize the statistics in the phase space as well as effective resampling strategies is discussed to handle realizability and stability issues. To test the performance of the blended algorithms, the forty dimensional Lorenz 96 system is utilized with a five dimensional subspace to run <span class="hlt">particles</span>. The <span class="hlt">filters</span> are tested extensively in various turbulent regimes with distinct statistics and with changing observation time frequency and both dense and sparse spatial observations. In real applications perfect dynamical models are always inaccessible considering the complexities in both modeling and computation of high dimensional turbulent system. The effects of model errors from imperfect modeling of the systems are also checked for these methods. The blended methods show uniformly high skill in both capturing non-Gaussian statistics and achieving accurate <span class="hlt">filtering</span> results in various dynamical regimes with and without model errors.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22304120','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22304120"><span id="translatedtitle"><span class="hlt">Optimization</span> of magnetic switches for single <span class="hlt">particle</span> and cell transport</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Abedini-Nassab, Roozbeh; Yellen, Benjamin B.; Murdoch, David M.; Kim, CheolGi</p> <p>2014-06-28</p> <p>The ability to manipulate an ensemble of single <span class="hlt">particles</span> and cells is a key aim of lab-on-a-chip research; however, the control mechanisms must be <span class="hlt">optimized</span> for minimal power consumption to enable future large-scale implementation. Recently, we demonstrated a matter transport platform, which uses overlaid patterns of magnetic films and metallic current lines to control magnetic <span class="hlt">particles</span> and magnetic-nanoparticle-labeled cells; however, we have made no prior attempts to <span class="hlt">optimize</span> the device geometry and power consumption. Here, we provide an <span class="hlt">optimization</span> analysis of <span class="hlt">particle</span>-switching devices based on stochastic variation in the <span class="hlt">particle</span>'s size and magnetic content. These results are immediately applicable to the design of robust, multiplexed platforms capable of transporting, sorting, and storing single cells in large arrays with low power and high efficiency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AIPC.1298..564B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AIPC.1298..564B"><span id="translatedtitle">Parameter Selection and Performance Study in <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bhattacharya, Indrajit; Samanta, Shukla</p> <p>2010-10-01</p> <p>The present paper describes the <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) technique and how different parameters in the algorithm may be selected in order to achieve faster convergence to the solution for a given <span class="hlt">optimization</span> problem. PSO has become a common heuristic technique in the <span class="hlt">optimization</span> community with many researchers exploring the concepts, issues and applications of the algorithm. PSO has undergone many changes since its introduction in 1995. As researchers have learnt about the technique, they have derived new versions, new applications and published theoretical studies of the effects of the various parameters and aspects of the algorithm. This paper comprises a snapshot of the <span class="hlt">particle</span> swarming, including variations in the algorithm, current and ongoing research, and applications. In this paper we first analyze the impact that the inertia weight and maximum velocity have on the performance of the <span class="hlt">particle</span> swarm <span class="hlt">optimizer</span>, and then provide guidelines for selecting these two parameters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70015521','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70015521"><span id="translatedtitle"><span class="hlt">Optimal</span>-adaptive <span class="hlt">filters</span> for modelling spectral shape, site amplification, and source scaling</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Safak, Erdal</p> <p>1989-01-01</p> <p>This paper introduces some applications of <span class="hlt">optimal</span> <span class="hlt">filtering</span> techniques to earthquake engineering by using the so-called ARMAX models. Three applications are presented: (a) spectral modelling of ground accelerations, (b) site amplification (i.e., the relationship between two records obtained at different sites during an earthquake), and (c) source scaling (i.e., the relationship between two records obtained at a site during two different earthquakes). A numerical example for each application is presented by using recorded ground motions. The results show that the <span class="hlt">optimal</span> <span class="hlt">filtering</span> techniques provide elegant solutions to above problems, and can be a useful tool in earthquake engineering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26906867','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26906867"><span id="translatedtitle"><span class="hlt">Optimized</span> design of N optical <span class="hlt">filters</span> for color and polarization imaging.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tu, Xingzhou; Pau, Stanley</p> <p>2016-02-01</p> <p>Designs of N optical <span class="hlt">filters</span> for color and polarization imaging are found by minimizing detector noise, photon shot noise, and interpolation error for the image acquisition in a division of focal plane configuration. To minimize interpolation error, a general tiling procedure and an <span class="hlt">optimized</span> tiling pattern for N <span class="hlt">filters</span> are presented. For multispectral imaging, a general technique to find the transmission band is presented. For full Stokes polarization imaging, the general design with <span class="hlt">optimized</span> retardances and fast angles of the polarizers is compared with the solution of the Thomson problem. These results are applied to the design of a three-color full Stokes imaging camera. PMID:26906867</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PMB....61.1888K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PMB....61.1888K"><span id="translatedtitle">Cardiac fiber tracking using adaptive <span class="hlt">particle</span> <span class="hlt">filtering</span> based on tensor rotation invariant in MRI</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kong, Fanhui; Liu, Wanyu; Magnin, Isabelle E.; Zhu, Yuemin</p> <p>2016-03-01</p> <p>Diffusion magnetic resonance imaging (dMRI) is a non-invasive method currently available for cardiac fiber tracking. However, accurate and efficient cardiac fiber tracking is still a challenge. This paper presents a probabilistic cardiac fiber tracking method based on <span class="hlt">particle</span> <span class="hlt">filtering</span>. In this framework, an adaptive sampling technique is presented to describe the posterior distribution of fiber orientations by adjusting the number and status of <span class="hlt">particles</span> according to the fractional anisotropy of diffusion. An observation model is then proposed to update the weight of <span class="hlt">particles</span> by rotating diffusion tensor from the primary eigenvector to a given fiber orientation while keeping the shape of the tensor invariant. The results on human cardiac dMRI show that the proposed method is robust to noise and outperforms conventional streamline and <span class="hlt">particle</span> <span class="hlt">filtering</span> techniques.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26864039','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26864039"><span id="translatedtitle">Cardiac fiber tracking using adaptive <span class="hlt">particle</span> <span class="hlt">filtering</span> based on tensor rotation invariant in MRI.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kong, Fanhui; Liu, Wanyu; Magnin, Isabelle E; Zhu, Yuemin</p> <p>2016-03-01</p> <p>Diffusion magnetic resonance imaging (dMRI) is a non-invasive method currently available for cardiac fiber tracking. However, accurate and efficient cardiac fiber tracking is still a challenge. This paper presents a probabilistic cardiac fiber tracking method based on <span class="hlt">particle</span> <span class="hlt">filtering</span>. In this framework, an adaptive sampling technique is presented to describe the posterior distribution of fiber orientations by adjusting the number and status of <span class="hlt">particles</span> according to the fractional anisotropy of diffusion. An observation model is then proposed to update the weight of <span class="hlt">particles</span> by rotating diffusion tensor from the primary eigenvector to a given fiber orientation while keeping the shape of the tensor invariant. The results on human cardiac dMRI show that the proposed method is robust to noise and outperforms conventional streamline and <span class="hlt">particle</span> <span class="hlt">filtering</span> techniques. PMID:26864039</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22306056','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22306056"><span id="translatedtitle">Boundary <span class="hlt">filters</span> for vector <span class="hlt">particles</span> passing parity breaking domains</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kolevatov, S. S.; Andrianov, A. A.</p> <p>2014-07-23</p> <p>The electrodynamics supplemented with a Lorenz and CPT invariance violating Chern-Simons (CS) action (Carrol-Field-Jackiw electrodynamics) is studied when the parity-odd medium is bounded by a hyperplane separating it from the vacuum. The solutions in both half-spaces are carefully discussed and for space-like boundary stitched on the boundary with help of the Bogolubov transformations. The presence of two different Fock vacua is shown. The passage of photons and massive vector mesons through a boundary between the CS medium and the vacuum of conventional Maxwell electrodynamics is investigated. Effects of reflection from a boundary (up to the total one) are revealed when vector <span class="hlt">particles</span> escape to vacuum and income from vacuum passing the boundary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25285187','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25285187"><span id="translatedtitle">A COMPARISON OF MODEL BASED AND DIRECT <span class="hlt">OPTIMIZATION</span> BASED <span class="hlt">FILTERING</span> ALGORITHMS FOR SHEARWAVE VELOCITY RECONSTRUCTION FOR ELECTRODE VIBRATION ELASTOGRAPHY.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ingle, Atul; Varghese, Tomy</p> <p>2013-04-01</p> <p>Tissue stiffness estimation plays an important role in cancer detection and treatment. The presence of stiffer regions in healthy tissue can be used as an indicator for the possibility of pathological changes. Electrode vibration elastography involves tracking of a mechanical shear wave in tissue using radio-frequency ultrasound echoes. Based on appropriate assumptions on tissue elasticity, this approach provides a direct way of measuring tissue stiffness from shear wave velocity, and enabling visualization in the form of tissue stiffness maps. In this study, two algorithms for shear wave velocity reconstruction in an electrode vibration setup are presented. The first method models the wave arrival time data using a hidden Markov model whose hidden states are local wave velocities that are estimated using a <span class="hlt">particle</span> <span class="hlt">filter</span> implementation. This is compared to a direct <span class="hlt">optimization</span>-based function fitting approach that uses sequential quadratic programming to estimate the unknown velocities and locations of interfaces. The mean shear wave velocities obtained using the two algorithms are within 10%of each other. Moreover, the Young's modulus estimates obtained from an incompressibility assumption are within 15 kPa of those obtained from the true stiffness data obtained from mechanical testing. Based on visual inspection of the two <span class="hlt">filtering</span> algorithms, the <span class="hlt">particle</span> <span class="hlt">filtering</span> method produces smoother velocity maps. PMID:25285187</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4180247','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4180247"><span id="translatedtitle">A COMPARISON OF MODEL BASED AND DIRECT <span class="hlt">OPTIMIZATION</span> BASED <span class="hlt">FILTERING</span> ALGORITHMS FOR SHEARWAVE VELOCITY RECONSTRUCTION FOR ELECTRODE VIBRATION ELASTOGRAPHY</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ingle, Atul; Varghese, Tomy</p> <p>2014-01-01</p> <p>Tissue stiffness estimation plays an important role in cancer detection and treatment. The presence of stiffer regions in healthy tissue can be used as an indicator for the possibility of pathological changes. Electrode vibration elastography involves tracking of a mechanical shear wave in tissue using radio-frequency ultrasound echoes. Based on appropriate assumptions on tissue elasticity, this approach provides a direct way of measuring tissue stiffness from shear wave velocity, and enabling visualization in the form of tissue stiffness maps. In this study, two algorithms for shear wave velocity reconstruction in an electrode vibration setup are presented. The first method models the wave arrival time data using a hidden Markov model whose hidden states are local wave velocities that are estimated using a <span class="hlt">particle</span> <span class="hlt">filter</span> implementation. This is compared to a direct <span class="hlt">optimization</span>-based function fitting approach that uses sequential quadratic programming to estimate the unknown velocities and locations of interfaces. The mean shear wave velocities obtained using the two algorithms are within 10%of each other. Moreover, the Young’s modulus estimates obtained from an incompressibility assumption are within 15 kPa of those obtained from the true stiffness data obtained from mechanical testing. Based on visual inspection of the two <span class="hlt">filtering</span> algorithms, the <span class="hlt">particle</span> <span class="hlt">filtering</span> method produces smoother velocity maps. PMID:25285187</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMEP52A..03G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMEP52A..03G"><span id="translatedtitle"><span class="hlt">Particle</span> sorting in <span class="hlt">Filter</span> Porous Media and in Sediment Transport: A Numerical and Experimental Study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Glascoe, L. G.; Ezzedine, S. M.; Kanarska, Y.; Lomov, I. N.; Antoun, T.; Smith, J.; Hall, R.; Woodson, S.</p> <p>2014-12-01</p> <p>Understanding the flow of fines, particulate sorting in porous media and fractured media during sediment transport is significant for industrial, environmental, geotechnical and petroleum technologies to name a few. For example, the safety of dam structures requires the characterization of the granular <span class="hlt">filter</span> ability to capture fine-soil <span class="hlt">particles</span> and prevent erosion failure in the event of an interfacial dislocation. Granular <span class="hlt">filters</span> are one of the most important protective design elements of large embankment dams. In case of cracking and erosion, if the <span class="hlt">filter</span> is capable of retaining the eroded fine <span class="hlt">particles</span>, then the crack will seal and the dam safety will be ensured. Here we develop and apply a numerical tool to thoroughly investigate the migration of fines in granular <span class="hlt">filters</span> at the grain scale. The numerical code solves the incompressible Navier-Stokes equations and uses a Lagrange multiplier technique. The numerical code is validated to experiments conducted at the USACE and ERDC. These laboratory experiments on soil transport and trapping in granular media are performed in constant-head flow chamber filled with the <span class="hlt">filter</span> media. Numerical solutions are compared to experimentally measured flow rates, pressure changes and base <span class="hlt">particle</span> distributions in the <span class="hlt">filter</span> layer and show good qualitative and quantitative agreement. To further the understanding of the soil transport in granular <span class="hlt">filters</span>, we investigated the sensitivity of the <span class="hlt">particle</span> clogging mechanism to various parameters such as <span class="hlt">particle</span> size ratio, the magnitude of hydraulic gradient, <span class="hlt">particle</span> concentration, and grain-to-grain contact properties. We found that for intermediate <span class="hlt">particle</span> size ratios, the high flow rates and low friction lead to deeper intrusion (or erosion) depths. We also found that the damage tends to be shallower and less severe with decreasing flow rate, increasing friction and concentration of suspended <span class="hlt">particles</span>. We have extended these results to more realistic heterogeneous population particulates for sediment transport. This work performed under the auspices of the US DOE by LLNL under Contract DE-AC52-07NA27344 and was sponsored by the Department of Homeland Security, Science and Technology Directorate, Homeland Security Advanced Research Projects Agency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26352448','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26352448"><span id="translatedtitle">Accelerating <span class="hlt">Particle</span> <span class="hlt">Filter</span> Using Randomized Multiscale and Fast Multipole Type Methods.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shabat, Gil; Shmueli, Yaniv; Bermanis, Amit; Averbuch, Amir</p> <p>2015-07-01</p> <p><span class="hlt">Particle</span> <span class="hlt">filter</span> is a powerful tool for state tracking using non-linear observations. We present a multiscale based method that accelerates the tracking computation by <span class="hlt">particle</span> <span class="hlt">filters</span>. Unlike the conventional way, which calculates weights over all <span class="hlt">particles</span> in each cycle of the algorithm, we sample a small subset from the source <span class="hlt">particles</span> using matrix decomposition methods. Then, we apply a function extension algorithm that uses a <span class="hlt">particle</span> subset to recover the density function for all the rest of the <span class="hlt">particles</span> not included in the chosen subset. The computational effort is substantial especially when multiple objects are tracked concurrently. The proposed algorithm significantly reduces the computational load. By using the Fast Gaussian Transform, the complexity of the <span class="hlt">particle</span> selection step is reduced to a linear time in n and k, where n is the number of <span class="hlt">particles</span> and k is the number of <span class="hlt">particles</span> in the selected subset. We demonstrate our method on both simulated and on real data such as object tracking in video sequences. PMID:26352448</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2716930','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2716930"><span id="translatedtitle">Dielectrophoretic manipulation of <span class="hlt">particles</span> in a modified microfluidic H <span class="hlt">filter</span> with multi-insulating blocks</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lewpiriyawong, Nuttawut; Yang, Chun; Lam, Yee Cheong</p> <p>2008-01-01</p> <p>The conventional microfluidic H <span class="hlt">filter</span> is modified with multi-insulating blocks to achieve a flow-through manipulation and separation of microparticles. The device transports <span class="hlt">particles</span> by exploiting electro-osmosis and electrophoresis, and manipulates <span class="hlt">particles</span> by utilizing dielectrophoresis (DEP). Polydimethylsiloxane (PDMS) blocks fabricated in the main channel of the PDMS H <span class="hlt">filter</span> induce a nonuniform electric field, which exerts a negative DEP force on the <span class="hlt">particles</span>. The use of multi-insulating blocks not only enhances the DEP force generated, but it also increases the controllability of the motion of the <span class="hlt">particles</span>, facilitating their manipulation and separation. Experiments were conducted to demonstrate the controlled flow direction of <span class="hlt">particles</span> by adjusting the applied voltages and the separation of <span class="hlt">particles</span> by size under two different input conditions, namely (i) a dc electric field mode and (ii) a combined ac and dc field mode. Numerical simulations elucidate the electrokinetic and hydrodynamic forces acting on a <span class="hlt">particle</span>, with theoretically predicted <span class="hlt">particle</span> trajectories in good agreement with those observed experimentally. In addition, the flow field was obtained experimentally with fluorescent tracer <span class="hlt">particles</span> using the microparticle image velocimetry (μ-PIV) technique. PMID:19693372</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JSV...364...30Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JSV...364...30Z"><span id="translatedtitle">Rheology behavior and <span class="hlt">optimal</span> damping effect of granular <span class="hlt">particles</span> in a non-obstructive <span class="hlt">particle</span> damper</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Kai; Chen, Tianning; Wang, Xiaopeng; Fang, Jianglong</p> <p>2016-03-01</p> <p>To explore the <span class="hlt">optimal</span> damping mechanism of non-obstructive <span class="hlt">particle</span> dampers (NOPDs), research on the relationship between the damping performance of NOPDs and the motion mode of damping <span class="hlt">particles</span> in NOPDs was carried out based on the rheological properties of vibrated granular <span class="hlt">particles</span>. Firstly, the damping performance of NOPDs under different excitation intensity and gap clearance was investigated via cantilever system experiments, and an approximate evaluation of the effective mass and effective damping of NOPDs was performed by fitting the experimental data to an equivalent single-degree-of-freedom (SDOF) system with no damping <span class="hlt">particles</span>. Then the phase diagrams which could show the motion mode of damping <span class="hlt">particles</span> under different excitation intensity and gap clearance were obtained via a series of vibration table tests. Moreover, the dissipation characteristic of damping <span class="hlt">particles</span> was explored by the discrete element method (DEM). The study results indicate that when NOPDs play the <span class="hlt">optimal</span> damping effect the granular Leidenfrost effect whereby the entire <span class="hlt">particle</span> bed in NOPDs is levitated above the vibrating base by a layer of highly energetic <span class="hlt">particles</span> is observed. Finally, the damping characteristics of NOPDs was explained by collisions and frictions between <span class="hlt">particle-particle</span> and <span class="hlt">particle</span>-wall based on the rheology behavior of damping <span class="hlt">particles</span> and a new dissipation mechanism was first proposed for the <span class="hlt">optimal</span> damping performance of NOPDs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011SPIE.8350E..0RY','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011SPIE.8350E..0RY"><span id="translatedtitle"><span class="hlt">Optimal</span> design of plate-fin heat exchangers by <span class="hlt">particle</span> swarm <span class="hlt">optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yousefi, M.; Darus, A. N.</p> <p>2011-12-01</p> <p>This study explores the application of <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) for <span class="hlt">optimization</span> of a cross-flow plate fin heat exchanger. Minimization total annual cost is the target of <span class="hlt">optimization</span>. Seven design parameters, namely, heat exchanger length at hot and cold sides, fin height, fin frequency, fin thickness, fin-strip length and number of hot side layers are selected as <span class="hlt">optimization</span> variables. A case study from the literature proves the effectiveness of the proposed algorithm in case of achieving more accurate results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17491466','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17491466"><span id="translatedtitle">A generic framework for tracking using <span class="hlt">particle</span> <span class="hlt">filter</span> with dynamic shape prior.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rathi, Yogesh; Vaswani, Namrata; Tannenbaum, Allen</p> <p>2007-05-01</p> <p>Tracking deforming objects involves estimating the global motion of the object and its local deformations as functions of time. Tracking algorithms using Kalman <span class="hlt">filters</span> or <span class="hlt">particle</span> <span class="hlt">filters</span> (PFs) have been proposed for tracking such objects, but these have limitations due to the lack of dynamic shape information. In this paper, we propose a novel method based on employing a locally linear embedding in order to incorporate dynamic shape information into the <span class="hlt">particle</span> <span class="hlt">filtering</span> framework for tracking highly deformable objects in the presence of noise and clutter. The PF also models image statistics such as mean and variance of the given data which can be useful in obtaining proper separation of object and background. PMID:17491466</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4433345','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4433345"><span id="translatedtitle">Markerless Human Motion Tracking Using Hierarchical Multi-Swarm Cooperative <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Saini, Sanjay; Zakaria, Nordin; Rambli, Dayang Rohaya Awang; Sulaiman, Suziah</p> <p>2015-01-01</p> <p>The high-dimensional search space involved in markerless full-body articulated human motion tracking from multiple-views video sequences has led to a number of solutions based on metaheuristics, the most recent form of which is <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO). However, the classical PSO suffers from premature convergence and it is trapped easily into local optima, significantly affecting the tracking accuracy. To overcome these drawbacks, we have developed a method for the problem based on Hierarchical Multi-Swarm Cooperative <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (H-MCPSO). The tracking problem is formulated as a non-linear 34-dimensional function <span class="hlt">optimization</span> problem where the fitness function quantifies the difference between the observed image and a projection of the model configuration. Both the silhouette and edge likelihoods are used in the fitness function. Experiments using Brown and HumanEva-II dataset demonstrated that H-MCPSO performance is better than two leading alternative approaches—Annealed <span class="hlt">Particle</span> <span class="hlt">Filter</span> (APF) and Hierarchical <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (HPSO). Further, the proposed tracking method is capable of automatic initialization and self-recovery from temporary tracking failures. Comprehensive experimental results are presented to support the claims. PMID:25978493</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25978493','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25978493"><span id="translatedtitle">Markerless human motion tracking using hierarchical multi-swarm cooperative <span class="hlt">particle</span> swarm <span class="hlt">optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Saini, Sanjay; Zakaria, Nordin; Rambli, Dayang Rohaya Awang; Sulaiman, Suziah</p> <p>2015-01-01</p> <p>The high-dimensional search space involved in markerless full-body articulated human motion tracking from multiple-views video sequences has led to a number of solutions based on metaheuristics, the most recent form of which is <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO). However, the classical PSO suffers from premature convergence and it is trapped easily into local optima, significantly affecting the tracking accuracy. To overcome these drawbacks, we have developed a method for the problem based on Hierarchical Multi-Swarm Cooperative <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (H-MCPSO). The tracking problem is formulated as a non-linear 34-dimensional function <span class="hlt">optimization</span> problem where the fitness function quantifies the difference between the observed image and a projection of the model configuration. Both the silhouette and edge likelihoods are used in the fitness function. Experiments using Brown and HumanEva-II dataset demonstrated that H-MCPSO performance is better than two leading alternative approaches-Annealed <span class="hlt">Particle</span> <span class="hlt">Filter</span> (APF) and Hierarchical <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (HPSO). Further, the proposed tracking method is capable of automatic initialization and self-recovery from temporary tracking failures. Comprehensive experimental results are presented to support the claims. PMID:25978493</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007RScI...78h5105A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007RScI...78h5105A"><span id="translatedtitle">High-efficiency particulate air <span class="hlt">filter</span> test stand and aerosol generator for <span class="hlt">particle</span> loading studies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arunkumar, R.; Hogancamp, Kristina U.; Parsons, Michael S.; Rogers, Donna M.; Norton, Olin P.; Nagel, Brian A.; Alderman, Steven L.; Waggoner, Charles A.</p> <p>2007-08-01</p> <p>This manuscript describes the design, characterization, and operational range of a test stand and high-output aerosol generator developed to evaluate the performance of 30×30×29cm3 nuclear grade high-efficiency particulate air (HEPA) <span class="hlt">filters</span> under variable, highly controlled conditions. The test stand system is operable at volumetric flow rates ranging from 1.5to12standardm3/min. Relative humidity levels are controllable from 5%-90% and the temperature of the aerosol stream is variable from ambient to 150°C. Test aerosols are produced through spray drying source material solutions that are introduced into a heated stainless steel evaporation chamber through an air-atomizing nozzle. Regulation of the <span class="hlt">particle</span> size distribution of the aerosol challenge is achieved by varying source solution concentrations and through the use of a postgeneration cyclone. The aerosol generation system is unique in that it facilitates the testing of standard HEPA <span class="hlt">filters</span> at and beyond rated media velocities by consistently providing, into a nominal flow of 7standardm3/min, high mass concentrations (˜25mg/m3) of dry aerosol streams having count mean diameters centered near the most penetrating <span class="hlt">particle</span> size for HEPA <span class="hlt">filters</span> (120-160nm). Aerosol streams that have been generated and characterized include those derived from various concentrations of KCl, NaCl, and sucrose solutions. Additionally, a water insoluble aerosol stream in which the solid component is predominantly iron (III) has been produced. Multiple ports are available on the test stand for making simultaneous aerosol measurements upstream and downstream of the test <span class="hlt">filter</span>. Types of <span class="hlt">filter</span> performance related studies that can be performed using this test stand system include <span class="hlt">filter</span> lifetime studies, <span class="hlt">filtering</span> efficiency testing, media velocity testing, evaluations under high mass loading and high humidity conditions, and determination of the downstream <span class="hlt">particle</span> size distributions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17764353','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17764353"><span id="translatedtitle">High-efficiency particulate air <span class="hlt">filter</span> test stand and aerosol generator for <span class="hlt">particle</span> loading studies.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Arunkumar, R; Hogancamp, Kristina U; Parsons, Michael S; Rogers, Donna M; Norton, Olin P; Nagel, Brian A; Alderman, Steven L; Waggoner, Charles A</p> <p>2007-08-01</p> <p>This manuscript describes the design, characterization, and operational range of a test stand and high-output aerosol generator developed to evaluate the performance of 30 x 30 x 29 cm(3) nuclear grade high-efficiency particulate air (HEPA) <span class="hlt">filters</span> under variable, highly controlled conditions. The test stand system is operable at volumetric flow rates ranging from 1.5 to 12 standard m(3)/min. Relative humidity levels are controllable from 5%-90% and the temperature of the aerosol stream is variable from ambient to 150 degrees C. Test aerosols are produced through spray drying source material solutions that are introduced into a heated stainless steel evaporation chamber through an air-atomizing nozzle. Regulation of the <span class="hlt">particle</span> size distribution of the aerosol challenge is achieved by varying source solution concentrations and through the use of a postgeneration cyclone. The aerosol generation system is unique in that it facilitates the testing of standard HEPA <span class="hlt">filters</span> at and beyond rated media velocities by consistently providing, into a nominal flow of 7 standard m(3)/min, high mass concentrations (approximately 25 mg/m(3)) of dry aerosol streams having count mean diameters centered near the most penetrating <span class="hlt">particle</span> size for HEPA <span class="hlt">filters</span> (120-160 nm). Aerosol streams that have been generated and characterized include those derived from various concentrations of KCl, NaCl, and sucrose solutions. Additionally, a water insoluble aerosol stream in which the solid component is predominantly iron (III) has been produced. Multiple ports are available on the test stand for making simultaneous aerosol measurements upstream and downstream of the test <span class="hlt">filter</span>. Types of <span class="hlt">filter</span> performance related studies that can be performed using this test stand system include <span class="hlt">filter</span> lifetime studies, <span class="hlt">filtering</span> efficiency testing, media velocity testing, evaluations under high mass loading and high humidity conditions, and determination of the downstream <span class="hlt">particle</span> size distributions. PMID:17764353</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JPhCS.395a2030J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JPhCS.395a2030J"><span id="translatedtitle">Thermal design of an electric motor using <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jandaud, P.-O.; Harmand, S.; Fakes, M.</p> <p>2012-11-01</p> <p>In this paper, flow inside an electric machine called starter-alternator is studied parametrically with CFD in order to be used by a thermal lumped model coupled to an <span class="hlt">optimization</span> algorithm using <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO). In a first case, the geometrical parameters are symmetric allowing us to model only one side of the machine. The <span class="hlt">optimized</span> thermal results are not conclusive. In a second case, all the parameters are independent. In this case, the flow is strongly influenced by the dissymmetry. <span class="hlt">Optimization</span> results are this time a clear improvement compared to the original machine.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AIPC.1159..206S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AIPC.1159..206S"><span id="translatedtitle">a Color Features-Based Method for Object Tracking Employing a <span class="hlt">Particle</span> <span class="hlt">Filter</span> Algorithm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sugandi, Budi; Kim, Hyoungseop; Tan, Joo Kooi; Ishikawa, Seiji</p> <p>2009-08-01</p> <p>We proposed a method for object tracking employing a <span class="hlt">particle</span> <span class="hlt">filter</span> based on color feature method. A histogram-based framework is used to describe the features. Histograms are useful because they have property that they allow changes in the object appearance while the histograms remain the same. <span class="hlt">Particle</span> <span class="hlt">filtering</span> is used because it is very robust for non-linear and non-Gaussian dynamic state estimation problems and performs well when clutter and occlusions are present on the image. Bhattacharyya distance is used to weight the samples in the <span class="hlt">particle</span> <span class="hlt">filter</span> by comparing each sample's histogram with a specified target model and it makes the measurement matching and sample's weight updating more reasonable. The method is capable to track successfully the moving object in different outdoor environment with and without initial positions information, and also, capable to track the moving object in the presence of occlusion using an appearance condition. In this paper, we propose a color features-based method for object tracking based on the <span class="hlt">particle</span> <span class="hlt">filters</span>. The experimental results and data show the feasibility and the effectiveness of our method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/9586197','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/9586197"><span id="translatedtitle">The effects of <span class="hlt">particle</span> charge on the performance of a <span class="hlt">filtering</span> facepiece.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, C C; Huang, S H</p> <p>1998-04-01</p> <p>This study quantitatively determined the effect of electrostatic charge on the performance of an electret <span class="hlt">filtering</span> facepiece. Monodisperse challenge corn oil aerosols with uniform charges were generated using a modified vibrating orifice monodisperse aerosol generator. The aerosol size distributions and concentrations upstream and downstream of an electret <span class="hlt">filter</span> were measured using an aerodynamic <span class="hlt">particle</span> sizer, an Aerosizer, and a scanning mobility <span class="hlt">particle</span> sizer. The aerosol charge was measured by using an aerosol electrometer. The tested electret <span class="hlt">filter</span> had a packing density of about 0.08, fiber size of 3 microns, and thickness of 0.75 mm. As expected, the primary filtration mechanisms for the micrometer-sized <span class="hlt">particles</span> are interception and impaction, especially at high face velocities, while electrostatic attraction and diffusion are the filtration mechanisms for submicrometer-sized aerosol <span class="hlt">particles</span>. The fiber charge density was estimated to be 1.35 x 10(-5) coulomb per square meter. After treatment with isopropanol, most of fiber charges were removed, causing the 0.3-micron aerosol penetration to increase from 36 to 68%. The air resistance of the <span class="hlt">filter</span> increased slightly after immersion in the isopropanol, probably due to the coating of impurities in isopropanol. The aerosol penetration decreased with increasing aerosol charge. The most penetrating aerosol size became larger as the aerosol charge increased, e.g., from 0.32 to 1.3 microns when the aerosol charge increased from 0 to 500 elementary charges. PMID:9586197</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=45584&keyword=TI&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=72077743&CFTOKEN=67274396','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=45584&keyword=TI&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=72077743&CFTOKEN=67274396"><span id="translatedtitle">X-RAY FLUORESCENCE ANALYSIS OF <span class="hlt">FILTER</span>-COLLECTED AEROSOL <span class="hlt">PARTICLES</span></span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>X-ray fluorescence (XRF) has become an effective technique for determining the elemental content of aerosol samples. For quantitative analysis, the aerosol <span class="hlt">particles</span> must be collected as uniform deposits on the surface of Teflon membrane <span class="hlt">filters</span>. An energy dispersive XRF spectrom...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9474E..0JD','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9474E..0JD"><span id="translatedtitle">A baker's dozen of new <span class="hlt">particle</span> flows for nonlinear <span class="hlt">filters</span>, Bayesian decisions and transport</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Daum, Fred; Huang, Jim</p> <p>2015-05-01</p> <p>We describe a baker's dozen of new <span class="hlt">particle</span> flows to compute Bayes' rule for nonlinear <span class="hlt">filters</span>, Bayesian decisions and learning as well as transport. Several of these new flows were inspired by transport theory, but others were inspired by physics or statistics or Markov chain Monte Carlo methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.3008P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.3008P"><span id="translatedtitle">Joint global <span class="hlt">optimization</span> of tomographic data based on <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> and decision theory</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Paasche, H.; Tronicke, J.</p> <p>2012-04-01</p> <p>In many near surface geophysical applications multiple tomographic data sets are routinely acquired to explore subsurface structures and parameters. Linking the model generation process of multi-method geophysical data sets can significantly reduce ambiguities in geophysical data analysis and model interpretation. Most geophysical inversion approaches rely on local search <span class="hlt">optimization</span> methods used to find an <span class="hlt">optimal</span> model in the vicinity of a user-given starting model. The final solution may critically depend on the initial model. Alternatively, global <span class="hlt">optimization</span> (GO) methods have been used to invert geophysical data. They explore the solution space in more detail and determine the <span class="hlt">optimal</span> model independently from the starting model. Additionally, they can be used to find sets of <span class="hlt">optimal</span> models allowing a further analysis of model parameter uncertainties. Here we employ <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO) to realize the global <span class="hlt">optimization</span> of tomographic data. PSO is an emergent methods based on swarm intelligence characterized by fast and robust convergence towards <span class="hlt">optimal</span> solutions. The fundamental principle of PSO is inspired by nature, since the algorithm mimics the behavior of a flock of birds searching food in a search space. In PSO, a number of <span class="hlt">particles</span> cruise a multi-dimensional solution space striving to find <span class="hlt">optimal</span> model solutions explaining the acquired data. The <span class="hlt">particles</span> communicate their positions and success and direct their movement according to the position of the currently most successful <span class="hlt">particle</span> of the swarm. The success of a <span class="hlt">particle</span>, i.e. the quality of the currently found model by a <span class="hlt">particle</span>, must be uniquely quantifiable to identify the swarm leader. When jointly inverting disparate data sets, the <span class="hlt">optimization</span> solution has to satisfy multiple <span class="hlt">optimization</span> objectives, at least one for each data set. Unique determination of the most successful <span class="hlt">particle</span> currently leading the swarm is not possible. Instead, only statements about the Pareto <span class="hlt">optimality</span> of the found solutions can be made. Identification of the leading <span class="hlt">particle</span> traditionally requires a costly combination of ranking and niching techniques. In our approach, we use a decision rule under uncertainty to identify the currently leading <span class="hlt">particle</span> of the swarm. In doing so, we consider the different objectives of our <span class="hlt">optimization</span> problem as competing agents with partially conflicting interests. Analysis of the maximin fitness function allows for robust and cheap identification of the currently leading <span class="hlt">particle</span>. The final <span class="hlt">optimization</span> result comprises a set of possible models spread along the Pareto front. For convex Pareto fronts, solution density is expected to be maximal in the region ideally compromising all objectives, i.e. the region of highest curvature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/835885','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/835885"><span id="translatedtitle">A STUDY ON ASH <span class="hlt">PARTICLE</span> DISTRIBUTION CHARACTERISITICS OF CANDLE <span class="hlt">FILTER</span> SURFACE REGENERATION AT ROOM TEMPERATURE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Vasudevan, V.; Kang, B.S-J.; Johnson, E.K.</p> <p>2002-09-19</p> <p>Ceramic barrier filtration is a leading technology employed in hot gas filtration. Hot gases loaded with ash <span class="hlt">particle</span> flow through the ceramic candle <span class="hlt">filters</span> and deposit ash on their outer surface. The deposited ash is periodically removed using back pulse cleaning jet, known as surface regeneration. The cleaning done by this technique still leaves some residual ash on the <span class="hlt">filter</span> surface, which over a period of time sinters, forms a solid cake and leads to mechanical failure of the candle <span class="hlt">filter</span>. A room temperature testing facility (RTTF) was built to gain more insight into the surface regeneration process before testing commenced at high temperature. RTTF was instrumented to obtain pressure histories during the surface regeneration process and a high-resolution high-speed imaging system was integrated in order to obtain pictures of the surface regeneration process. The objective of this research has been to utilize the RTTF to study the surface regeneration process at the convenience of room temperature conditions. The face velocity of the fluidized gas, the regeneration pressure of the back pulse and the time to build up ash on the surface of the candle <span class="hlt">filter</span> were identified as the important parameters to be studied. Two types of ceramic candle <span class="hlt">filters</span> were used in the study. Each candle <span class="hlt">filter</span> was subjected to several cycles of ash build-up followed by a thorough study of the surface regeneration process at different parametric conditions. The pressure histories in the chamber and <span class="hlt">filter</span> system during build-up and regeneration were then analyzed. The size distribution and movement of the ash <span class="hlt">particles</span> during the surface regeneration process was studied. Effect of each of the parameters on the performance of the regeneration process is presented. A comparative study between the two candle <span class="hlt">filters</span> with different characteristics is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4431276','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4431276"><span id="translatedtitle">Integration of GPS Precise Point Positioning and MEMS-Based INS Using Unscented <span class="hlt">Particle</span> <span class="hlt">Filter</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Abd Rabbou, Mahmoud; El-Rabbany, Ahmed</p> <p>2015-01-01</p> <p>Integration of Global Positioning System (GPS) and Inertial Navigation System (INS) integrated system involves nonlinear motion state and measurement models. However, the extended Kalman <span class="hlt">filter</span> (EKF) is commonly used as the estimation <span class="hlt">filter</span>, which might lead to solution divergence. This is usually encountered during GPS outages, when low-cost micro-electro-mechanical sensors (MEMS) inertial sensors are used. To enhance the navigation system performance, alternatives to the standard EKF should be considered. <span class="hlt">Particle</span> <span class="hlt">filtering</span> (PF) is commonly considered as a nonlinear estimation technique to accommodate severe MEMS inertial sensor biases and noise behavior. However, the computation burden of PF limits its use. In this study, an improved version of PF, the unscented <span class="hlt">particle</span> <span class="hlt">filter</span> (UPF), is utilized, which combines the unscented Kalman <span class="hlt">filter</span> (UKF) and PF for the integration of GPS precise point positioning and MEMS-based inertial systems. The proposed <span class="hlt">filter</span> is examined and compared with traditional estimation <span class="hlt">filters</span>, namely EKF, UKF and PF. Tightly coupled mechanization is adopted, which is developed in the raw GPS and INS measurement domain. Un-differenced ionosphere-free linear combinations of pseudorange and carrier-phase measurements are used for PPP. The performance of the UPF is analyzed using a real test scenario in downtown Kingston, Ontario. It is shown that the use of UPF reduces the number of samples needed to produce an accurate solution, in comparison with the traditional PF, which in turn reduces the processing time. In addition, UPF enhances the positioning accuracy by up to 15% during GPS outages, in comparison with EKF. However, all <span class="hlt">filters</span> produce comparable results when the GPS measurement updates are available. PMID:25815446</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120008933','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120008933"><span id="translatedtitle">Nonlinear Motion Cueing Algorithm: <span class="hlt">Filtering</span> at Pilot Station and Development of the Nonlinear <span class="hlt">Optimal</span> <span class="hlt">Filters</span> for Pitch and Roll</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zaychik, Kirill B.; Cardullo, Frank M.</p> <p>2012-01-01</p> <p>Telban and Cardullo have developed and successfully implemented the non-linear <span class="hlt">optimal</span> motion cueing algorithm at the Visual Motion Simulator (VMS) at the NASA Langley Research Center in 2005. The latest version of the non-linear algorithm performed <span class="hlt">filtering</span> of motion cues in all degrees-of-freedom except for pitch and roll. This manuscript describes the development and implementation of the non-linear <span class="hlt">optimal</span> motion cueing algorithm for the pitch and roll degrees of freedom. Presented results indicate improved cues in the specified channels as compared to the original design. To further advance motion cueing in general, this manuscript describes modifications to the existing algorithm, which allow for <span class="hlt">filtering</span> at the location of the pilot's head as opposed to the centroid of the motion platform. The rational for such modification to the cueing algorithms is that the location of the pilot's vestibular system must be taken into account as opposed to the off-set of the centroid of the cockpit relative to the center of rotation alone. Results provided in this report suggest improved performance of the motion cueing algorithm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3984833','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3984833"><span id="translatedtitle">Support Vector Machine Based on Adaptive Acceleration <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Abdulameer, Mohammed Hasan; Othman, Zulaiha Ali</p> <p>2014-01-01</p> <p>Existing face recognition methods utilize <span class="hlt">particle</span> swarm <span class="hlt">optimizer</span> (PSO) and opposition based <span class="hlt">particle</span> swarm <span class="hlt">optimizer</span> (OPSO) to <span class="hlt">optimize</span> the parameters of SVM. However, the utilization of random values in the velocity calculation decreases the performance of these techniques; that is, during the velocity computation, we normally use random values for the acceleration coefficients and this creates randomness in the solution. To address this problem, an adaptive acceleration <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (AAPSO) technique is proposed. To evaluate our proposed method, we employ both face and iris recognition based on AAPSO with SVM (AAPSO-SVM). In the face and iris recognition systems, performance is evaluated using two human face databases, YALE and CASIA, and the UBiris dataset. In this method, we initially perform feature extraction and then recognition on the extracted features. In the recognition process, the extracted features are used for SVM training and testing. During the training and testing, the SVM parameters are <span class="hlt">optimized</span> with the AAPSO technique, and in AAPSO, the acceleration coefficients are computed using the <span class="hlt">particle</span> fitness values. The parameters in SVM, which are <span class="hlt">optimized</span> by AAPSO, perform efficiently for both face and iris recognition. A comparative analysis between our proposed AAPSO-SVM and the PSO-SVM technique is presented. PMID:24790584</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23523646','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23523646"><span id="translatedtitle"><span class="hlt">Optimizing</span> the bandpass <span class="hlt">filter</span> for acoustic stimuli in recording ocular vestibular-evoked myogenic potentials.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Shou-Jen; Jaw, Fu-Shan; Young, Yi-Ho</p> <p>2013-05-10</p> <p>This study aimed to determine the <span class="hlt">optimal</span> bandpass <span class="hlt">filter</span> (BPF) setting for acoustic stimuli in recording the ocular vestibular-evoked myogenic potential (oVEMP). Twelve healthy volunteers underwent oVEMP tests using acoustic stimuli with various high-pass <span class="hlt">filters</span> (1, 10 and 100Hz) and low-pass <span class="hlt">filters</span> (500, 1000 and 2000Hz). Initially, various effects of high-pass <span class="hlt">filter</span> on the oVEMPs were examined under Conditions A (BPF of 1-1000Hz), B (BPF of 10-1000Hz) and C (BPF of 100-1000Hz). Of these conditions, Condition A showed 100% response rate and had larger nI-pI amplitude than Conditions B and C. Thus, Condition A was selected for subsequent analysis of the various effects of low-pass <span class="hlt">filter</span> on the oVEMPs. However, Condition A (BPF of 1-1000Hz) did not significantly differ from Conditions D (BPF of 1-500Hz) and E (BPF of 1-2000Hz) in terms of the latencies and amplitudes of oVEMPs. Condition A thus is supposed to be the <span class="hlt">optimal</span> recording condition for oVEMPs. In conclusion, the <span class="hlt">optimal</span> BPF setting for acoustic stimuli in recording oVEMPs is suggested to be between 1 and 1000Hz. PMID:23523646</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8401E..0RM','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8401E..0RM"><span id="translatedtitle"><span class="hlt">Optimization</span> of high speed pipelining in FPGA-based FIR <span class="hlt">filter</span> design using genetic algorithm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meyer-Baese, Uwe; Botella, Guillermo; Romero, David E. T.; Kumm, Martin</p> <p>2012-06-01</p> <p>This paper compares FPGA-based full pipelined multiplierless FIR <span class="hlt">filter</span> design options. Comparison of Distributed Arithmetic (DA), Common Sub-Expression (CSE) sharing and n-dimensional Reduced Adder Graph (RAG-n) multiplierless <span class="hlt">filter</span> design methods in term of size, speed, and A*T product are provided. Since DA designs are table-based and CSE/RAG-n designs are adder-based, FPGA synthesis design data are used for a realistic comparison. Superior results of a genetic algorithm based <span class="hlt">optimization</span> of pipeline registers and non-output fundamental coefficients are shown. FIR <span class="hlt">filters</span> (posted as open source by Kastner et al.) for <span class="hlt">filters</span> in the length from 6 to 151 coefficients are used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1615059E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1615059E"><span id="translatedtitle">Station Based Polynomial Modeling of the local ionospheric Vertical Total Electron Content (VTEC) using <span class="hlt">Particle</span> <span class="hlt">Filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Erdogan, Eren; Onur Karslioglu, Mahmut; Durmaz, Murat; Aghakarimi, Armin</p> <p>2014-05-01</p> <p>In this study, <span class="hlt">particle</span> <span class="hlt">filter</span> (PF) which is mainly based on the Monte Carlo simulation technique has been carried out for polynomial modeling of the local ionospheric conditions above the selected ground based stations. Less sensitivity to the errors caused by linearization of models and the effect of unknown or unmodeled components in the system model is one of the advantages of the <span class="hlt">particle</span> <span class="hlt">filter</span> as compared to the Kalman <span class="hlt">filter</span> which is commonly used as a recursive <span class="hlt">filtering</span> method in VTEC modeling. Besides, probability distribution of the system models is not necessarily required to be Gaussian. In this work third order polynomial function has been incorporated into the <span class="hlt">particle</span> <span class="hlt">filter</span> implementation to represent the local VTEC distribution. Coefficients of the polynomial model presenting the ionospheric parameters and the receiver inter frequency biases are the unknowns forming the state vector which has been estimated epoch-wise for each ground station. To consider the time varying characteristics of the regional VTEC distribution, dynamics of the state vector parameters changing permanently have been modeled using the first order Gauss-Markov process. In the processing of the <span class="hlt">particle</span> <span class="hlt">filtering</span>, multi-variety probability distribution of the state vector through the time has been approximated by means of randomly selected samples and their associated weights. A known drawback of the <span class="hlt">particle</span> <span class="hlt">filtering</span> is that the increasing number of the state vector parameters results in an inefficient <span class="hlt">filter</span> performance and requires more samples to represent the probability distribution of the state vector. Considering the total number of unknown parameters for all ground stations, estimation of these parameters which were inserted into a single state vector has caused the <span class="hlt">particle</span> <span class="hlt">filter</span> to produce inefficient results. To solve this problem, the PF implementation has been carried out separately for each ground station at current time epochs. After estimation of unknown parameters, Ionospheric VTEC map covering the predefined region has been produced by interpolation. VTEC values at a grid node of the map have been computed based on the four closest ground stations by means of inverse distance squared weighted average. The GPS data which is acquired from ground based stations have been made available from the International GNSS Service (IGS) and the Reference Frame Sub-commission for Europe (EUREF). Raw GPS observations have been preprocessed to detect cycle slips and to form geometry-free linear combinations of observables for each continuous arc. Then the obtained pseudoranges have been smoothed with the carrier to code leveling method. Finally, the performance of the <span class="hlt">particle</span> <span class="hlt">filter</span> to investigate the local characteristics of the ionospheric Vertical Total Electron Content (VTEC) has been evaluated and the result has been compared with the result of a standard Kalman <span class="hlt">filter</span>. Keywords: ionosphere, GPS , <span class="hlt">Particle</span> filer, VTEC modeling</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AcMSn.tmp..113Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AcMSn.tmp..113Y"><span id="translatedtitle">Plate/shell topological <span class="hlt">optimization</span> subjected to linear buckling constraints by adopting composite exponential <span class="hlt">filtering</span> function</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ye, Hong-Ling; Wang, Wei-Wei; Chen, Ning; Sui, Yun-Kang</p> <p>2015-11-01</p> <p>In this paper, a model of topology <span class="hlt">optimization</span> with linear buckling constraints is established based on an independent and continuous mapping method to minimize the plate/shell structure weight. A composite exponential function (CEF) is selected as <span class="hlt">filtering</span> functions for element weight, the element stiffness matrix and the element geometric stiffness matrix, which recognize the design variables, and to implement the changing process of design variables from "discrete" to "continuous" and back to "discrete". The buckling constraints are approximated as explicit formulations based on the Taylor expansion and the <span class="hlt">filtering</span> function. The <span class="hlt">optimization</span> model is transformed to dual programming and solved by the dual sequence quadratic programming algorithm. Finally, three numerical examples with power function and CEF as <span class="hlt">filter</span> function are analyzed and discussed to demonstrate the feasibility and efficiency of the proposed method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhyA..447...49D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhyA..447...49D"><span id="translatedtitle">Performance <span class="hlt">optimization</span> of total momentum <span class="hlt">filtering</span> double-resonance energy selective electron heat pump</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ding, Ze-Min; Chen, Lin-Gen; Ge, Yan-Lin; Sun, Feng-Rui</p> <p>2016-04-01</p> <p>A theoretical model for energy selective electron (ESE) heat pumps operating with two-dimensional electron reservoirs is established in this study. In this model, a double-resonance energy <span class="hlt">filter</span> operating with a total momentum <span class="hlt">filtering</span> mechanism is considered for the transmission of electrons. The <span class="hlt">optimal</span> thermodynamic performance of the ESE heat pump devices is also investigated. Numerical calculations show that the heating load of the device with two resonances is larger, whereas the coefficient of performance (COP) is lower than the ESE heat pump when considering a single-resonance <span class="hlt">filter</span>. The performance characteristics of the ESE heat pumps in the total momentum <span class="hlt">filtering</span> condition are generally superior to those with a conventional <span class="hlt">filtering</span> mechanism. In particular, the performance characteristics of the ESE heat pumps considering a conventional <span class="hlt">filtering</span> mechanism are vastly different from those of a device with total momentum <span class="hlt">filtering</span>, which is induced by extra electron momentum in addition to the horizontal direction. Parameters such as resonance width and energy spacing are found to be associated with the performance of the electron system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4416937','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4416937"><span id="translatedtitle">A Neural Network-Based <span class="hlt">Optimal</span> Spatial <span class="hlt">Filter</span> Design Method for Motor Imagery Classification</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yuksel, Ayhan; Olmez, Tamer</p> <p>2015-01-01</p> <p>In this study, a novel spatial <span class="hlt">filter</span> design method is introduced. Spatial <span class="hlt">filtering</span> is an important processing step for feature extraction in motor imagery-based brain-computer interfaces. This paper introduces a new motor imagery signal classification method combined with spatial <span class="hlt">filter</span> <span class="hlt">optimization</span>. We simultaneously train the spatial <span class="hlt">filter</span> and the classifier using a neural network approach. The proposed spatial <span class="hlt">filter</span> network (SFN) is composed of two layers: a spatial <span class="hlt">filtering</span> layer and a classifier layer. These two layers are linked to each other with non-linear mapping functions. The proposed method addresses two shortcomings of the common spatial patterns (CSP) algorithm. First, CSP aims to maximize the between-classes variance while ignoring the minimization of within-classes variances. Consequently, the features obtained using the CSP method may have large within-classes variances. Second, the maximizing <span class="hlt">optimization</span> function of CSP increases the classification accuracy indirectly because an independent classifier is used after the CSP method. With SFN, we aimed to maximize the between-classes variance while minimizing within-classes variances and simultaneously <span class="hlt">optimizing</span> the spatial <span class="hlt">filter</span> and the classifier. To classify motor imagery EEG signals, we modified the well-known feed-forward structure and derived forward and backward equations that correspond to the proposed structure. We tested our algorithm on simple toy data. Then, we compared the SFN with conventional CSP and its multi-class version, called one-versus-rest CSP, on two data sets from BCI competition III. The evaluation results demonstrate that SFN is a good alternative for classifying motor imagery EEG signals with increased classification accuracy. PMID:25933101</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25933101','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25933101"><span id="translatedtitle">A neural network-based <span class="hlt">optimal</span> spatial <span class="hlt">filter</span> design method for motor imagery classification.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yuksel, Ayhan; Olmez, Tamer</p> <p>2015-01-01</p> <p>In this study, a novel spatial <span class="hlt">filter</span> design method is introduced. Spatial <span class="hlt">filtering</span> is an important processing step for feature extraction in motor imagery-based brain-computer interfaces. This paper introduces a new motor imagery signal classification method combined with spatial <span class="hlt">filter</span> <span class="hlt">optimization</span>. We simultaneously train the spatial <span class="hlt">filter</span> and the classifier using a neural network approach. The proposed spatial <span class="hlt">filter</span> network (SFN) is composed of two layers: a spatial <span class="hlt">filtering</span> layer and a classifier layer. These two layers are linked to each other with non-linear mapping functions. The proposed method addresses two shortcomings of the common spatial patterns (CSP) algorithm. First, CSP aims to maximize the between-classes variance while ignoring the minimization of within-classes variances. Consequently, the features obtained using the CSP method may have large within-classes variances. Second, the maximizing <span class="hlt">optimization</span> function of CSP increases the classification accuracy indirectly because an independent classifier is used after the CSP method. With SFN, we aimed to maximize the between-classes variance while minimizing within-classes variances and simultaneously <span class="hlt">optimizing</span> the spatial <span class="hlt">filter</span> and the classifier. To classify motor imagery EEG signals, we modified the well-known feed-forward structure and derived forward and backward equations that correspond to the proposed structure. We tested our algorithm on simple toy data. Then, we compared the SFN with conventional CSP and its multi-class version, called one-versus-rest CSP, on two data sets from BCI competition III. The evaluation results demonstrate that SFN is a good alternative for classifying motor imagery EEG signals with increased classification accuracy. PMID:25933101</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27023034','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27023034"><span id="translatedtitle"><span class="hlt">Particle</span> Density Using Deposition <span class="hlt">Filters</span> at the Full Scale RDD Experiments.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Berg, Rodney; Gilhuly, Colleen; Korpach, Ed; Ungar, Kurt</p> <p>2016-05-01</p> <p>During the Full-Scale Radiological Dispersal Device (FSRDD) Field Trials carried out in Suffield, Alberta, Canada, several suites of detection equipment and software models were used to measure and characterize the ground deposition. The FSRDD Field Trials were designed to disperse radioactive lanthanum of known activity to better understand such an event. This paper focuses on one means of measuring both concentration and the <span class="hlt">particle</span> size distribution of the deposition using electrostatic <span class="hlt">filters</span> placed around the trial site to collect deposited <span class="hlt">particles</span> for analysis. The measurements made from ground deposition <span class="hlt">filters</span> provided a basis to guide modeling and validate results by giving insight on how <span class="hlt">particles</span> are distributed by a plume. PMID:27023034</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18726819','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18726819"><span id="translatedtitle">Evaluation of the effect of media velocity on <span class="hlt">filter</span> efficiency and most penetrating <span class="hlt">particle</span> size of nuclear grade high-efficiency particulate air <span class="hlt">filters</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alderman, Steven L; Parsons, Michael S; Hogancamp, Kristina U; Waggoner, Charles A</p> <p>2008-11-01</p> <p>High-efficiency particulate air (HEPA) <span class="hlt">filters</span> are widely used to control particulate matter emissions from processes that involve management or treatment of radioactive materials. Section FC of the American Society of Mechanical Engineers AG-1 Code on Nuclear Air and Gas Treatment currently restricts media velocity to a maximum of 2.5 cm/sec in any application where this standard is invoked. There is some desire to eliminate or increase this media velocity limit. A concern is that increasing media velocity will result in higher emissions of ultrafine <span class="hlt">particles</span>; thus, it is unlikely that higher media velocities will be allowed without data to demonstrate the effect of media velocity on removal of ultrafine <span class="hlt">particles</span>. In this study, the performance of nuclear grade HEPA <span class="hlt">filters</span>, with respect to <span class="hlt">filter</span> efficiency and most penetrating <span class="hlt">particle</span> size, was evaluated as a function of media velocity. Deep-pleat nuclear grade HEPA <span class="hlt">filters</span> (31 cm x 31 cm x 29 cm) were evaluated at media velocities ranging from 2.0 to 4.5 cm/sec using a potassium chloride aerosol challenge having a <span class="hlt">particle</span> size distribution centered near the HEPA <span class="hlt">filter</span> most penetrating <span class="hlt">particle</span> size. <span class="hlt">Filters</span> were challenged under two distinct mass loading rate regimes through the use of or exclusion of a 3 microm aerodynamic diameter cut point cyclone. <span class="hlt">Filter</span> efficiency and most penetrating <span class="hlt">particle</span> size measurements were made throughout the duration of <span class="hlt">filter</span> testing. <span class="hlt">Filter</span> efficiency measured at the onset of aerosol challenge was noted to decrease with increasing media velocity, with values ranging from 99.999 to 99.977%. The <span class="hlt">filter</span> most penetrating <span class="hlt">particle</span> size recorded at the onset of testing was noted to decrease slightly as media velocity was increased and was typically in the range of 110-130 nm. Although additional testing is needed, these findings indicate that <span class="hlt">filters</span> operating at media velocities up to 4.5 cm/sec will meet or exceed current <span class="hlt">filter</span> efficiency requirements. Additionally, increased emission of ultrafine <span class="hlt">particles</span> is seemingly negligible. PMID:18726819</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SPIE.7182E..1GZ','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SPIE.7182E..1GZ"><span id="translatedtitle">Microscopy with spatial <span class="hlt">filtering</span> for sorting <span class="hlt">particles</span> and monitoring subcellular morphology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zheng, Jing-Yi; Qian, Zhen; Pasternack, Robert M.; Boustany, Nada N.</p> <p>2009-02-01</p> <p>Optical scatter imaging (OSI) was developed to non-invasively track real-time changes in <span class="hlt">particle</span> morphology with submicron sensitivity in situ without exogenous labeling, cell fixing, or organelle isolation. For spherical <span class="hlt">particles</span>, the intensity ratio of wide-to-narrow angle scatter (OSIR, Optical Scatter Image Ratio) was shown to decrease monotonically with diameter and agree with Mie theory. In living cells, we recently reported this technique is able to detect mitochondrial morphological alterations, which were mediated by the Bcl-xL transmembrane domain, and could not be observed by fluorescence or differential interference contrast images. Here we further extend the ability of morphology assessment by adopting a digital micromirror device (DMD) for Fourier <span class="hlt">filtering</span>. When placed in the Fourier plane the DMD can be used to select scattering intensities at desired combination of scattering angles. We designed an optical <span class="hlt">filter</span> bank consisting of Gabor-like <span class="hlt">filters</span> with various scales and rotations based on Gabor <span class="hlt">filters</span>, which have been widely used for localization of spatial and frequency information in digital images and texture analysis. Using a model system consisting of mixtures of polystyrene spheres and bacteria, we show how this system can be used to sort <span class="hlt">particles</span> on a microscopic slide based on their size, orientation and aspect ratio. We are currently applying this technique to characterize the morphology of subcellular organelles to help understand fundamental biological processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AIPC.1558..578B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AIPC.1558..578B"><span id="translatedtitle">Genetic algorithm and <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> combined with Powell method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bento, David; Pinho, Diana; Pereira, Ana I.; Lima, Rui</p> <p>2013-10-01</p> <p>In recent years, the population algorithms are becoming increasingly robust and easy to use, based on Darwin's Theory of Evolution, perform a search for the best solution around a population that will progress according to several generations. This paper present variants of hybrid genetic algorithm - Genetic Algorithm and a bio-inspired hybrid algorithm - <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span>, both combined with the local method - Powell Method. The developed methods were tested with twelve test functions from unconstrained <span class="hlt">optimization</span> context.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011OptEn..50i0502W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011OptEn..50i0502W"><span id="translatedtitle"><span class="hlt">Particle</span> probability hypothesis density <span class="hlt">filtering</span> for multitarget visual tracking with robust state extraction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Jingjing; Hu, Shiqiang; Wang, Yang</p> <p>2011-09-01</p> <p><span class="hlt">Particle</span> probability hypothesis density (PHD) <span class="hlt">filter</span>-based visual trackers have achieved considerable success in the visual tracking field. But position measurements based on detection may not have enough ability to discriminate an object from clutter, and accurate state extraction cannot be obtained in the original PHD <span class="hlt">filtering</span> framework, especially when targets can appear, disappear, merge, or split at any time. To meet the limitations, the proposed algorithm combines a color histogram of a target and the temporal dynamics in a unifying framework and a Gaussian mixture model clustering method for efficient state extraction is designed. The proposed tracker can improve the accuracy of state estimation in tracking a variable number of objects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1117081','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1117081"><span id="translatedtitle">Estimation of the Dynamic States of Synchronous Machines Using an Extended <span class="hlt">Particle</span> <span class="hlt">Filter</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhou, Ning; Meng, Da; Lu, Shuai</p> <p>2013-11-11</p> <p>In this paper, an extended <span class="hlt">particle</span> <span class="hlt">filter</span> (PF) is proposed to estimate the dynamic states of a synchronous machine using phasor measurement unit (PMU) data. A PF propagates the mean and covariance of states via Monte Carlo simulation, is easy to implement, and can be directly applied to a non-linear system with non-Gaussian noise. The extended PF modifies a basic PF to improve robustness. Using Monte Carlo simulations with practical noise and model uncertainty considerations, the extended PF’s performance is evaluated and compared with the basic PF and an extended Kalman <span class="hlt">filter</span> (EKF). The extended PF results showed high accuracy and robustness against measurement and model noise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.6678B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.6678B"><span id="translatedtitle">Applying a fully nonlinear <span class="hlt">particle</span> <span class="hlt">filter</span> on a coupled ocean-atmosphere climate model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Browne, Philip; van Leeuwen, Peter Jan; Wilson, Simon</p> <p>2014-05-01</p> <p>It is a widely held assumption that <span class="hlt">particle</span> <span class="hlt">filters</span> are not applicable in high-dimensional systems due to <span class="hlt">filter</span> degeneracy, commonly called the curse of dimensionality. This is only true of naive <span class="hlt">particle</span> <span class="hlt">filters</span>, and indeed it has been shown much more advanced methods perform particularly well on systems of dimension up to 216 ≡ 6.5 × 104. In this talk we will present results from using the equivalent weights <span class="hlt">particle</span> <span class="hlt">filter</span> in twin experiments with the global climate model HadCM3. These experiments have a number of notable features. Firstly the sheer size of model in use is substantially larger than has been previously achieved. The model has state dimension approximately 4 × 106 and approximately 4 × 104 observations per analysis step. This is 2 orders of magnitude more than has been achieved with a <span class="hlt">particle</span> <span class="hlt">filter</span> in the geosciences. Secondly, the use of a fully nonlinear data assimilation technique to initialise a climate model gives us the possibility to find non-Gaussian estimates for the current state of the climate. In doing so we may find that the same model may demonstrate multiple likely scenarios for forecasts on a multi-annular/decadal timescale. The experiments consider to assimilating artificial sea surface temperatures daily for several years. We will discuss how an ensemble based method for assimilation in a coupled system avoids issues faced by variational methods. Practical details of how the experiments were carried out, specifically the use of the EMPIRE data assimilation framework, will be discussed. The results from applying the nonlinear data assimilation method can always be improved through having a better representation of the model error covariance matrix. We will discuss the representation which we have used for this matrix, and in particular, how it was generated from the coupled system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4474858','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4474858"><span id="translatedtitle">A Modified <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> Technique for Finding <span class="hlt">Optimal</span> Designs for Mixture Models</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wong, Weng Kee; Chen, Ray-Bing; Huang, Chien-Chih; Wang, Weichung</p> <p>2015-01-01</p> <p><span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) is a meta-heuristic algorithm that has been shown to be successful in solving a wide variety of real and complicated <span class="hlt">optimization</span> problems in engineering and computer science. This paper introduces a projection based PSO technique, named ProjPSO, to efficiently find different types of <span class="hlt">optimal</span> designs, or nearly <span class="hlt">optimal</span> designs, for mixture models with and without constraints on the components, and also for related models, like the log contrast models. We also compare the modified PSO performance with Fedorov's algorithm, a popular algorithm used to generate <span class="hlt">optimal</span> designs, Cocktail algorithm, and the recent algorithm proposed by [1]. PMID:26091237</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EUCAS...6..263O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EUCAS...6..263O"><span id="translatedtitle"><span class="hlt">Optimization</span>-based tuning of LPV fault detection <span class="hlt">filters</span> for civil transport aircraft</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ossmann, D.; Varga, A.</p> <p>2013-12-01</p> <p>In this paper, a two-step <span class="hlt">optimal</span> synthesis approach of robust fault detection (FD) <span class="hlt">filters</span> for the model based diagnosis of sensor faults for an augmented civil aircraft is suggested. In the first step, a direct analytic synthesis of a linear parameter varying (LPV) FD <span class="hlt">filter</span> is performed for the open-loop aircraft using an extension of the nullspace based synthesis method to LPV systems. In the second step, a multiobjective <span class="hlt">optimization</span> problem is solved for the <span class="hlt">optimal</span> tuning of the LPV detector parameters to ensure satisfactory FD performance for the augmented nonlinear closed-loop aircraft. Worst-case global search has been employed to assess the robustness of the fault detection system in the presence of aerodynamics uncertainties and estimation errors in the aircraft parameters. An application of the proposed method is presented for the detection of failures in the angle-of-attack sensor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19830033191&hterms=water+filter&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dwater%2Bfilter','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19830033191&hterms=water+filter&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dwater%2Bfilter"><span id="translatedtitle"><span class="hlt">Optimal</span> interpolation and the Kalman <span class="hlt">filter</span>. [for analysis of numerical weather predictions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cohn, S.; Isaacson, E.; Ghil, M.</p> <p>1981-01-01</p> <p>The estimation theory of stochastic-dynamic systems is described and used in a numerical study of <span class="hlt">optimal</span> interpolation. The general form of data assimilation methods is reviewed. The Kalman-Bucy, KB <span class="hlt">filter</span>, and <span class="hlt">optimal</span> interpolation (OI) <span class="hlt">filters</span> are examined for effectiveness in performance as gain matrices using a one-dimensional form of the shallow-water equations. Control runs in the numerical analyses were performed for a ten-day forecast in concert with the OI method. The effects of <span class="hlt">optimality</span>, initialization, and assimilation were studied. It was found that correct initialization is necessary in order to localize errors, especially near boundary points. Also, the use of small forecast error growth rates over data-sparse areas was determined to offset inaccurate modeling of correlation functions near boundaries.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993gnc..conf.1740A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993gnc..conf.1740A"><span id="translatedtitle">Development of an <span class="hlt">optimized</span> LEB <span class="hlt">filter</span> and its application to INS/GPS test data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Antonini, Claudio D.</p> <p></p> <p>An <span class="hlt">optimized</span> linear-ellipsoidal-bounded (LEB) <span class="hlt">filter</span> has been developed and applied to data obtained from a ground test using a combined INS/GPS configuration. In this cascaded configuration, the <span class="hlt">filter</span> receives eight outputs from the INS (accelerations, velocity, angles, altitude) and six outputs from the GPS (velocities and positions). The GPS measurements have included the effect of SA of varying or unknown spectrum which, although likely to be estimated and compensated with some modelling techniques at the expense of including extra state variables, could also be dealt with the approach indicated in this article at much less effort. An <span class="hlt">optimized</span> formulation for the LEB <span class="hlt">filter</span> is presented in which the volume of the ellipsoid containing the estimation errors is minimized at every step or at selected intervals. The SA effect is modelled as an unknown-but-bounded (UBB) noise process. Comparisons with an Extended Kalman <span class="hlt">filter</span> (KF) show that KF innovations are not white and the LEB <span class="hlt">filter</span> estimates are one order of magnitude smaller that those produced by the KF.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013IJEEP..14..477B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013IJEEP..14..477B"><span id="translatedtitle">Decoupled Control Strategy of Grid Interactive Inverter System with <span class="hlt">Optimal</span> LCL <span class="hlt">Filter</span> Design</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Babu, B. Chitti; Anurag, Anup; Sowmya, Tontepu; Marandi, Debati; Bal, Satarupa</p> <p>2013-09-01</p> <p>This article presents a control strategy for a three-phase grid interactive voltage source inverter that links a renewable energy source to the utility grid through a LCL-type <span class="hlt">filter</span>. An <span class="hlt">optimized</span> LCL-type <span class="hlt">filter</span> has been designed and modeled so as to reduce the current harmonics in the grid, considering the conduction and switching losses at constant modulation index (Ma). The control strategy adopted here decouples the active and reactive power loops, thus achieving desirable performance with independent control of active and reactive power injected into the grid. The startup transients can also be controlled by the implementation of this proposed control strategy: in addition to this, <span class="hlt">optimal</span> LCL <span class="hlt">filter</span> with lesser conduction and switching copper losses as well as core losses. A trade-off has been made between the total losses in the LCL <span class="hlt">filter</span> and the Total Harmonic Distortion (THD%) of the grid current, and the <span class="hlt">filter</span> inductor has been designed accordingly. In order to study the dynamic performance of the system and to confirm the analytical results, the models are simulated in the MATLAB/Simulink environment, and the results are analyzed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1010409','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1010409"><span id="translatedtitle">Design <span class="hlt">Optimization</span> of Vena Cava <span class="hlt">Filters</span>: An application to dual filtration devices</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Singer, M A; Wang, S L; Diachin, D P</p> <p>2009-12-03</p> <p>Pulmonary embolism (PE) is a significant medical problem that results in over 300,000 fatalities per year. A common preventative treatment for PE is the insertion of a metallic <span class="hlt">filter</span> into the inferior vena cava that traps thrombi before they reach the lungs. The goal of this work is to use methods of mathematical modeling and design <span class="hlt">optimization</span> to determine the configuration of trapped thrombi that minimizes the hemodynamic disruption. The resulting configuration has implications for constructing an <span class="hlt">optimally</span> designed vena cava <span class="hlt">filter</span>. Computational fluid dynamics is coupled with a nonlinear <span class="hlt">optimization</span> algorithm to determine the <span class="hlt">optimal</span> configuration of trapped model thrombus in the inferior vena cava. The location and shape of the thrombus are parameterized, and an objective function, based on wall shear stresses, determines the worthiness of a given configuration. The methods are fully automated and demonstrate the capabilities of a design <span class="hlt">optimization</span> framework that is broadly applicable. Changes to thrombus location and shape alter the velocity contours and wall shear stress profiles significantly. For vena cava <span class="hlt">filters</span> that trap two thrombi simultaneously, the undesirable flow dynamics past one thrombus can be mitigated by leveraging the flow past the other thrombus. Streamlining the shape of thrombus trapped along the cava wall reduces the disruption to the flow, but increases the area exposed to abnormal wall shear stress. Computer-based design <span class="hlt">optimization</span> is a useful tool for developing vena cava <span class="hlt">filters</span>. Characterizing and parameterizing the design requirements and constraints is essential for constructing devices that address clinical complications. In addition, formulating a well-defined objective function that quantifies clinical risks and benefits is needed for designing devices that are clinically viable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007SPIE.6508E..0MD','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007SPIE.6508E..0MD"><span id="translatedtitle">Multiple hypothesis shape tracking using <span class="hlt">particle</span> <span class="hlt">filtering</span> and Hough-based observation models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dore, Alessio; Asadi, Majid; Regazzoni, Carlo S.</p> <p>2007-01-01</p> <p>In the last years, the <span class="hlt">Particle</span> <span class="hlt">Filter</span> algorithm has been extensively proposed and employed for handling the problem of visual tracking of multiple moving objects under different assumptions. This wide usage is due to the capability of performing a recursive multiple hypothesis state estimation for non-linear non-Gaussian motion and observation models. In this paper a method, based on the <span class="hlt">Particle</span> <span class="hlt">Filter</span> framework, is proposed for multiple objects tracking, exploiting a target representation consisting of position and shape described as a fixed dimensionality vector composed by a fixed number of grouped target corners. However, usually, application domains of visual tracking algorithms are characterized by non-rigid objects and high occlusions rate entailing new corners to appear and others to disappear at each frame. In order to cope with this problem, a voting method (i.e. the Generalized Hough Transform) is employed to estimate the likelihood function to weight different propagated <span class="hlt">particles</span> (i.e. multiple corners configurations describing shapes) by means of the corners extracted from the currently observed image. This method, in addition to the high dimensionality of the state representation, depicts the two main particularities of the presented <span class="hlt">Particle</span> <span class="hlt">Filter</span>. The proposed algorithm has been tested in a real-world domain and experiments indicate good results in tracking both rigid and non-rigid objects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21592912','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21592912"><span id="translatedtitle">Integration of fuzzy spatial information in tracking based on <span class="hlt">particle</span> <span class="hlt">filtering</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Widynski, Nicolas; Dubuisson, Séverine; Bloch, Isabelle</p> <p>2011-06-01</p> <p>In this paper, we propose a novel method to introduce spatial information in <span class="hlt">particle</span> <span class="hlt">filters</span>. This information may be expressed as spatial relations (orientation, distance, etc.), velocity, scaling, or shape information. Spatial information is modeled in a generic fuzzy-set framework. The fuzzy models are then introduced in the <span class="hlt">particle</span> <span class="hlt">filter</span> and automatically define transition and prior spatial distributions. We also propose an efficient importance distribution to produce relevant <span class="hlt">particles</span>, which is dedicated to the proposed fuzzy framework. The fuzzy modeling provides flexibility both in the semantics of information and in the transitions from one instant to another one. This allows one to take into account situations where a tracked object changes its direction in a quite abrupt way and where poor prior information on dynamics is available, as demonstrated on synthetic data. As an illustration, two tests on real video sequences are performed in this paper. The first one concerns a classical tracking problem and shows that our approach efficiently tracks objects with complex and unknown dynamics, outperforming classical <span class="hlt">filtering</span> techniques while using only a small number of <span class="hlt">particles</span>. In the second experiment, we show the flexibility of our approach for modeling: Fuzzy shapes are modeled in a generic way and allow the tracking of objects with changing shape. PMID:21592912</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19700488','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19700488"><span id="translatedtitle">Large <span class="hlt">particle</span> penetration through N95 respirator <span class="hlt">filters</span> and facepiece leaks with cyclic flow.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cho, Kyungmin Jacob; Reponen, Tiina; McKay, Roy; Shukla, Rakesh; Haruta, Hiroki; Sekar, Padmini; Grinshpun, Sergey A</p> <p>2010-01-01</p> <p>The aim of this study was to investigate respirator <span class="hlt">filter</span> and faceseal penetration of <span class="hlt">particles</span> representing bacterial and fungal spore size ranges (0.7-4 mum). First, field experiments were conducted to determine workplace protection factors (WPFs) for a typical N95 <span class="hlt">filtering</span> facepiece respirator (FFR). These data (average WPF = 515) were then used to position the FFR on a manikin to simulate realistic donning conditions for laboratory experiments. <span class="hlt">Filter</span> penetration was also measured after the FFR was fully sealed on the manikin face. This value was deducted from the total penetration (obtained from tests with the partially sealed FFR) to determine the faceseal penetration. All manikin experiments were repeated using three sinusoidal breathing flow patterns corresponding to mean inspiratory flow rates of 15, 30, and 85 l min(-1). The faceseal penetration varied from 0.1 to 1.1% and decreased with increasing <span class="hlt">particle</span> size (P < 0.001) and breathing rate (P < 0.001). The fractions of aerosols penetrating through the faceseal leakage varied from 0.66 to 0.94. In conclusion, even for a well-fitting FFR respirator, most <span class="hlt">particle</span> penetration occurs through faceseal leakage, which varies with breathing flow rate and <span class="hlt">particle</span> size. PMID:19700488</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006SPIE.6360E..0LB','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006SPIE.6360E..0LB"><span id="translatedtitle"><span class="hlt">Optimal</span> band selection in hyperspectral remote sensing of aquatic benthic features: a wavelet <span class="hlt">filter</span> window approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bostater, Charles R., Jr.</p> <p>2006-09-01</p> <p>This paper describes a wavelet based approach to derivative spectroscopy. The approach is utilized to select, through <span class="hlt">optimization</span>, <span class="hlt">optimal</span> channels or bands to use as derivative based remote sensing algorithms. The approach is applied to airborne and modeled or synthetic reflectance signatures of environmental media and features or objects within such media, such as benthic submerged vegetation canopies. The technique can also applied to selected pixels identified within a hyperspectral image cube obtained from an board an airborne, ground based, or subsurface mobile imaging system. This wavelet based image processing technique is an extremely fast numerical method to conduct higher order derivative spectroscopy which includes nonlinear <span class="hlt">filter</span> windows. Essentially, the wavelet <span class="hlt">filter</span> scans a measured or synthetic signature in an automated sequential manner in order to develop a library of <span class="hlt">filtered</span> spectra. The library is utilized in real time to select the <span class="hlt">optimal</span> channels for direct algorithm application. The unique wavelet based derivative <span class="hlt">filtering</span> technique makes us of a translating, and dilating derivative spectroscopy signal processing (TDDS-SP (R)) approach based upon remote sensing science and radiative transfer processes unlike other signal processing techniques applied to hyperspectral signatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26569247','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26569247"><span id="translatedtitle"><span class="hlt">Optimization</span> Algorithm for Kalman <span class="hlt">Filter</span> Exploiting the Numerical Characteristics of SINS/GPS Integrated Navigation Systems.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hu, Shaoxing; Xu, Shike; Wang, Duhu; Zhang, Aiwu</p> <p>2015-01-01</p> <p>Aiming at addressing the problem of high computational cost of the traditional Kalman <span class="hlt">filter</span> in SINS/GPS, a practical <span class="hlt">optimization</span> algorithm with offline-derivation and parallel processing methods based on the numerical characteristics of the system is presented in this paper. The algorithm exploits the sparseness and/or symmetry of matrices to simplify the computational procedure. Thus plenty of invalid operations can be avoided by offline derivation using a block matrix technique. For enhanced efficiency, a new parallel computational mechanism is established by subdividing and restructuring calculation processes after analyzing the extracted "useful" data. As a result, the algorithm saves about 90% of the CPU processing time and 66% of the memory usage needed in a classical Kalman <span class="hlt">filter</span>. Meanwhile, the method as a numerical approach needs no precise-loss transformation/approximation of system modules and the accuracy suffers little in comparison with the <span class="hlt">filter</span> before computational <span class="hlt">optimization</span>. Furthermore, since no complicated matrix theories are needed, the algorithm can be easily transplanted into other modified <span class="hlt">filters</span> as a secondary <span class="hlt">optimization</span> method to achieve further efficiency. PMID:26569247</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4701286','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4701286"><span id="translatedtitle"><span class="hlt">Optimization</span> Algorithm for Kalman <span class="hlt">Filter</span> Exploiting the Numerical Characteristics of SINS/GPS Integrated Navigation Systems</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hu, Shaoxing; Xu, Shike; Wang, Duhu; Zhang, Aiwu</p> <p>2015-01-01</p> <p>Aiming at addressing the problem of high computational cost of the traditional Kalman <span class="hlt">filter</span> in SINS/GPS, a practical <span class="hlt">optimization</span> algorithm with offline-derivation and parallel processing methods based on the numerical characteristics of the system is presented in this paper. The algorithm exploits the sparseness and/or symmetry of matrices to simplify the computational procedure. Thus plenty of invalid operations can be avoided by offline derivation using a block matrix technique. For enhanced efficiency, a new parallel computational mechanism is established by subdividing and restructuring calculation processes after analyzing the extracted “useful” data. As a result, the algorithm saves about 90% of the CPU processing time and 66% of the memory usage needed in a classical Kalman <span class="hlt">filter</span>. Meanwhile, the method as a numerical approach needs no precise-loss transformation/approximation of system modules and the accuracy suffers little in comparison with the <span class="hlt">filter</span> before computational <span class="hlt">optimization</span>. Furthermore, since no complicated matrix theories are needed, the algorithm can be easily transplanted into other modified <span class="hlt">filters</span> as a secondary <span class="hlt">optimization</span> method to achieve further efficiency. PMID:26569247</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/6632838','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/6632838"><span id="translatedtitle">An <span class="hlt">optimal</span> linear <span class="hlt">filter</span> for the reduction of noise superimposed to the EEG signal.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bartoli, F; Cerutti, S</p> <p>1983-10-01</p> <p>In the present paper a procedure for the reduction of super-imposed noise on EEG tracings is described, which makes use of linear digital <span class="hlt">filtering</span> and identification methods. In particular, an <span class="hlt">optimal</span> <span class="hlt">filter</span> (a Kalman <span class="hlt">filter</span>) has been developed which is intended to capture the disturbances of the electromyographic noise on the basis of an a priori modelling which considers a series of impulses with a temporal occurrence according to a Poisson distribution as a noise generating mechanism. The experimental results refer to the EEG tracings recorded from 20 patients in normal resting conditions: the procedure consists of a preprocessing phase (which uses also a low-pass FIR digital <span class="hlt">filter</span>), followed by the implementation of the identification and the Kalman <span class="hlt">filter</span>. The performance of the <span class="hlt">filters</span> is satisfactory also from the clinical standpoint, obtaining a marked reduction of noise without distorting the useful information contained in the signal. Furthermore, when using the introduced method, the EEG signal generating mechanism is accordingly parametrized as AR/ARMA models, thus obtaining an extremely sensitive feature extraction with interesting and not yet completely studied pathophysiological meanings. The above procedure may find a general application in the field of noise reduction and the better enhancement of information contained in the wide set of biological signals. PMID:6632838</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009pcms.confE..89B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009pcms.confE..89B"><span id="translatedtitle">Sub-<span class="hlt">Optimal</span> Ensemble <span class="hlt">Filters</span> and distributed hydrologic modeling: a new challenge in flood forecasting</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baroncini, F.; Castelli, F.</p> <p>2009-09-01</p> <p>Data assimilation techniques based on Ensemble <span class="hlt">Filtering</span> are widely regarded as the best approach in solving forecast and calibration problems in geophysics models. Often the implementation of statistical <span class="hlt">optimal</span> techniques, like the Ensemble Kalman <span class="hlt">Filter</span>, is unfeasible because of the large amount of replicas used in each time step of the model for updating the error covariance matrix. Therefore the sub <span class="hlt">optimal</span> approach seems to be a more suitable choice. Various sub-<span class="hlt">optimal</span> techniques were tested in atmospheric and oceanographic models, some of them are based on the detection of a "null space". Distributed Hydrologic Models differ from the other geo-fluid-dynamics models in some fundamental aspects that make complex to understanding the relative efficiency of the different suboptimal techniques. Those aspects include threshold processes , preferential trajectories for convection and diffusion, low observability of the main state variables and high parametric uncertainty. This research study is focused on such topics and explore them through some numerical experiments on an continuous hydrologic model, MOBIDIC. This model include both water mass balance and surface energy balance, so it's able to assimilate a wide variety of datasets like traditional hydrometric "on ground" measurements or land surface temperature retrieval from satellite. The experiments that we present concern to a basin of 700 kmq in center Italy, with hourly dataset on a 8 months period that includes both drought and flood events, in this first set of experiment we worked on a low spatial resolution version of the hydrologic model (3.2 km). A new Kalman <span class="hlt">Filter</span> based algorithm is presented : this <span class="hlt">filter</span> try to address the main challenges of hydrological modeling uncertainty. The proposed <span class="hlt">filter</span> use in Forecast step a COFFEE (Complementary Orthogonal <span class="hlt">Filter</span> For Efficient Ensembles) approach with a propagation of both deterministic and stochastic ensembles to improve robustness and convergence proprieties. After, through a P.O.D. Reduction from control theory, we compute a Reduced Order Forecast Covariance matrix . In analysis step the <span class="hlt">filter</span> uses a LE (Local Ensemble) Kalman <span class="hlt">Filter</span> approach. We modify the LE Kalman <span class="hlt">Filter</span> assimilation scheme and we adapt its formulation to the P.O.D. Reduced sub-space propagated in forecast step. Through this, assimilation of observations is made only in the maximum covariance directions of the model error. Then the efficiency of this technique is weighed in term of hydrometric forecast accuracy in a preliminary convergence test of a synthetic rainfall event toward a real rain fall event.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060035916&hterms=fortran+code&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dfortran%2Bcode','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060035916&hterms=fortran+code&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dfortran%2Bcode"><span id="translatedtitle"><span class="hlt">Optimization</span> of <span class="hlt">Particle</span>-in-Cell Codes on RISC Processors</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Decyk, Viktor K.; Karmesin, Steve Roy; Boer, Aeint de; Liewer, Paulette C.</p> <p>1996-01-01</p> <p>General strategies are developed to <span class="hlt">optimize</span> <span class="hlt">particle</span>-cell-codes written in Fortran for RISC processors which are commonly used on massively parallel computers. These strategies include data reorganization to improve cache utilization and code reorganization to improve efficiency of arithmetic pipelines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25300451','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25300451"><span id="translatedtitle">Combining Video, Audio and Lexical Indicators of Affect in Spontaneous Conversation via <span class="hlt">Particle</span> <span class="hlt">Filtering</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Savran, Arman; Cao, Houwei; Shah, Miraj; Nenkova, Ani; Verma, Ragini</p> <p>2012-01-01</p> <p>We present experiments on fusing facial video, audio and lexical indicators for affect estimation during dyadic conversations. We use temporal statistics of texture descriptors extracted from facial video, a combination of various acoustic features, and lexical features to create regression based affect estimators for each modality. The single modality regressors are then combined using <span class="hlt">particle</span> <span class="hlt">filtering</span>, by treating these independent regression outputs as measurements of the affect states in a Bayesian <span class="hlt">filtering</span> framework, where previous observations provide prediction about the current state by means of learned affect dynamics. Tested on the Audio-visual Emotion Recognition Challenge dataset, our single modality estimators achieve substantially higher scores than the official baseline method for every dimension of affect. Our <span class="hlt">filtering</span>-based multi-modality fusion achieves correlation performance of 0.344 (baseline: 0.136) and 0.280 (baseline: 0.096) for the fully continuous and word level sub challenges, respectively. PMID:25300451</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4187218','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4187218"><span id="translatedtitle">Combining Video, Audio and Lexical Indicators of Affect in Spontaneous Conversation via <span class="hlt">Particle</span> <span class="hlt">Filtering</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Savran, Arman; Cao, Houwei; Shah, Miraj; Nenkova, Ani; Verma, Ragini</p> <p>2013-01-01</p> <p>We present experiments on fusing facial video, audio and lexical indicators for affect estimation during dyadic conversations. We use temporal statistics of texture descriptors extracted from facial video, a combination of various acoustic features, and lexical features to create regression based affect estimators for each modality. The single modality regressors are then combined using <span class="hlt">particle</span> <span class="hlt">filtering</span>, by treating these independent regression outputs as measurements of the affect states in a Bayesian <span class="hlt">filtering</span> framework, where previous observations provide prediction about the current state by means of learned affect dynamics. Tested on the Audio-visual Emotion Recognition Challenge dataset, our single modality estimators achieve substantially higher scores than the official baseline method for every dimension of affect. Our <span class="hlt">filtering</span>-based multi-modality fusion achieves correlation performance of 0.344 (baseline: 0.136) and 0.280 (baseline: 0.096) for the fully continuous and word level sub challenges, respectively. PMID:25300451</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24663450','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24663450"><span id="translatedtitle">Two-dimensional temperature measurements in <span class="hlt">particle</span> loaded technical flames by <span class="hlt">filtered</span> Rayleigh scattering.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Müller, D; Pagel, R; Burkert, A; Wagner, V; Paa, W</p> <p>2014-03-20</p> <p><span class="hlt">Filtered</span> Rayleigh scattering (FRS) is applied to determine two-dimensional temperature distributions in a hexamethyldisiloxane loaded propane/air flame intended for combustion chemical vapor deposition processes. An iodine cell as a molecular <span class="hlt">filter</span> suppresses background scattering, e.g., by <span class="hlt">particles</span>, while the wings of the spectrally broadened Rayleigh scattering can pass this <span class="hlt">filter</span>. A frequency-doubled Nd:YAG laser is tuned to a strong absorption line of iodine. The gas temperature is deduced from the transmitted Rayleigh scattering signal. Since FRS also depends on molecule-specific scattering cross sections, the local gas composition of majority species is measured using the Raman scattering technique. Limits and restrictions are discussed. PMID:24663450</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20150009149&hterms=decompose&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ddecompose','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20150009149&hterms=decompose&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ddecompose"><span id="translatedtitle"><span class="hlt">Optimized</span> FPGA Implementation of Multi-Rate FIR <span class="hlt">Filters</span> Through Thread Decomposition</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zheng, Jason Xin; Nguyen, Kayla; He, Yutao</p> <p>2010-01-01</p> <p>Multirate (decimation/interpolation) <span class="hlt">filters</span> are among the essential signal processing components in spaceborne instruments where Finite Impulse Response (FIR) <span class="hlt">filters</span> are often used to minimize nonlinear group delay and finite-precision effects. Cascaded (multi-stage) designs of Multi-Rate FIR (MRFIR) <span class="hlt">filters</span> are further used for large rate change ratio, in order to lower the required throughput while simultaneously achieving comparable or better performance than single-stage designs. Traditional representation and implementation of MRFIR employ polyphase decomposition of the original <span class="hlt">filter</span> structure, whose main purpose is to compute only the needed output at the lowest possible sampling rate. In this paper, an alternative representation and implementation technique, called TD-MRFIR (Thread Decomposition MRFIR), is presented. The basic idea is to decompose MRFIR into output computational threads, in contrast to a structural decomposition of the original <span class="hlt">filter</span> as done in the polyphase decomposition. Each thread represents an instance of the finite convolution required to produce a single output of the MRFIR. The <span class="hlt">filter</span> is thus viewed as a finite collection of concurrent threads. The technical details of TD-MRFIR will be explained, first showing its applicability to the implementation of downsampling, upsampling, and resampling FIR <span class="hlt">filters</span>, and then describing a general strategy to <span class="hlt">optimally</span> allocate the number of <span class="hlt">filter</span> taps. A particular FPGA design of multi-stage TD-MRFIR for the L-band radar of NASA's SMAP (Soil Moisture Active Passive) instrument is demonstrated; and its implementation results in several targeted FPGA devices are summarized in terms of the functional (bit width, fixed-point error) and performance (time closure, resource usage, and power estimation) parameters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120016941','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120016941"><span id="translatedtitle">Statistical Orbit Determination using the <span class="hlt">Particle</span> <span class="hlt">Filter</span> for Incorporating Non-Gaussian Uncertainties</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mashiku, Alinda; Garrison, James L.; Carpenter, J. Russell</p> <p>2012-01-01</p> <p>The tracking of space objects requires frequent and accurate monitoring for collision avoidance. As even collision events with very low probability are important, accurate prediction of collisions require the representation of the full probability density function (PDF) of the random orbit state. Through representing the full PDF of the orbit state for orbit maintenance and collision avoidance, we can take advantage of the statistical information present in the heavy tailed distributions, more accurately representing the orbit states with low probability. The classical methods of orbit determination (i.e. Kalman <span class="hlt">Filter</span> and its derivatives) provide state estimates based on only the second moments of the state and measurement errors that are captured by assuming a Gaussian distribution. Although the measurement errors can be accurately assumed to have a Gaussian distribution, errors with a non-Gaussian distribution could arise during propagation between observations. Moreover, unmodeled dynamics in the orbit model could introduce non-Gaussian errors into the process noise. A <span class="hlt">Particle</span> <span class="hlt">Filter</span> (PF) is proposed as a nonlinear <span class="hlt">filtering</span> technique that is capable of propagating and estimating a more complete representation of the state distribution as an accurate approximation of a full PDF. The PF uses Monte Carlo runs to generate <span class="hlt">particles</span> that approximate the full PDF representation. The PF is applied in the estimation and propagation of a highly eccentric orbit and the results are compared to the Extended Kalman <span class="hlt">Filter</span> and Splitting Gaussian Mixture algorithms to demonstrate its proficiency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009MeScT..20e5203A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009MeScT..20e5203A"><span id="translatedtitle">Hybrid extended <span class="hlt">particle</span> <span class="hlt">filter</span> (HEPF) for integrated inertial navigation and global positioning systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aggarwal, Priyanka; Syed, Zainab; El-Sheimy, Naser</p> <p>2009-05-01</p> <p>Navigation includes the integration of methodologies and systems for estimating time-varying position, velocity and attitude of moving objects. Navigation incorporating the integrated inertial navigation system (INS) and global positioning system (GPS) generally requires extensive evaluations of nonlinear equations involving double integration. Currently, integrated navigation systems are commonly implemented using the extended Kalman <span class="hlt">filter</span> (EKF). The EKF assumes a linearized process, measurement models and Gaussian noise distributions. These assumptions are unrealistic for highly nonlinear systems like land vehicle navigation and may cause <span class="hlt">filter</span> divergence. A <span class="hlt">particle</span> <span class="hlt">filter</span> (PF) is developed to enhance integrated INS/GPS system performance as it can easily deal with nonlinearity and non-Gaussian noises. In this paper, a hybrid extended <span class="hlt">particle</span> <span class="hlt">filter</span> (HEPF) is developed as an alternative to the well-known EKF to achieve better navigation data accuracy for low-cost microelectromechanical system sensors. The results show that the HEPF performs better than the EKF during GPS outages, especially when simulated outages are located in periods with high vehicle dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25240099','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25240099"><span id="translatedtitle">Retention of radioactive <span class="hlt">particles</span> and associated effects in the <span class="hlt">filter</span>-feeding marine mollusc Mytilus edulis.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jaeschke, B C; Lind, O C; Bradshaw, C; Salbu, B</p> <p>2015-01-01</p> <p>Radioactive <span class="hlt">particles</span> are aggregates of radioactive atoms that may contain significant activity concentrations. They have been released into the environment from nuclear weapons tests, and from accidents and effluents associated with the nuclear fuel cycle. Aquatic <span class="hlt">filter</span>-feeders can capture and potentially retain radioactive <span class="hlt">particles</span>, which could then provide concentrated doses to nearby tissues. This study experimentally investigated the retention and effects of radioactive <span class="hlt">particles</span> in the blue mussel, Mytilus edulis. Spent fuel <span class="hlt">particles</span> originating from the Dounreay nuclear establishment, and collected in the field, comprised a U and Al alloy containing fission products such as (137)Cs and (90)Sr/(90)Y. <span class="hlt">Particles</span> were introduced into mussels in suspension with plankton-food or through implantation in the extrapallial cavity. Of the <span class="hlt">particles</span> introduced with food, 37% were retained for 70 h, and were found on the siphon or gills, with the notable exception of one <span class="hlt">particle</span> that was ingested and found in the stomach. <span class="hlt">Particles</span> not retained seemed to have been actively rejected and expelled by the mussels. The largest and most radioactive <span class="hlt">particle</span> (estimated dose rate 3.18 ± 0.06 Gyh(-1)) induced a significant increase in Comet tail-DNA %. In one case this <span class="hlt">particle</span> caused a large white mark (suggesting necrosis) in the mantle tissue with a simultaneous increase in micronucleus frequency observed in the haemolymph collected from the muscle, implying that non-targeted effects of radiation were induced by radiation from the retained <span class="hlt">particle</span>. White marks found in the tissue were attributed to ionising radiation and physical irritation. The results indicate that current methods used for risk assessment, based upon the absorbed dose equivalent limit and estimating the "no-effect dose" are inadequate for radioactive <span class="hlt">particle</span> exposures. Knowledge is lacking about the ecological implications of radioactive <span class="hlt">particles</span> released into the environment, for example potential recycling within a population, or trophic transfer in the food chain. PMID:25240099</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007SPIE.6786E..1GL','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007SPIE.6786E..1GL"><span id="translatedtitle">Real-time target tracking with <span class="hlt">particle</span> <span class="hlt">filter</span> in moving monocular camera</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Guocheng; Wang, Yongji</p> <p>2007-11-01</p> <p>In this paper, we propose an improved <span class="hlt">particle</span> <span class="hlt">filter</span> algorithm for real-time tracking a randomly moving target in dynamic environment with a moving monocular camera. For making the tracking task robustly and effectively, color histogram based target model is integrated into <span class="hlt">particle</span> <span class="hlt">filter</span> algorithm. Bhattacharyya distance is used to weight samples by calculating each sample's histogram with a specified target model and it makes the measurement matching and samples' weight updating more reasonable. In order to reduce sample depletion, the improved algorithm will be able to take the latest observation into account. The experimental results confirm that the method is effective even when the monocular camera is moving and the target object is partially occluded in a clutter background.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010SPIE.7539E..0ZS','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010SPIE.7539E..0ZS"><span id="translatedtitle">Active visual tracking method self-adapting to illumination based on <span class="hlt">particle</span> <span class="hlt">filter</span> pre-location</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Su, Jie; Yin, Guisheng; Wei, Zhenhua; Xie, Yining</p> <p>2010-01-01</p> <p>To improve the identification rate and tracking rate for quickly moving target, expand tracking scope and lower the sensitivity to illumination varying, an active visual tracking system self-adapting to illumination based on <span class="hlt">particle</span> <span class="hlt">filter</span> pre-location is proposed. The algorithm of object pre-location based on <span class="hlt">particle</span> <span class="hlt">filter</span> is used to realize realtime tracking to moving target by forecasting its location and control camera joints of Tilt and Pan. The method resetting system is used to improve accuracy of system. Brightness histogram equalization method is used to reduce the affect of illuminating varying in pre-location algorithm. Experiments and property analysis show that the real-time and accuracy are greatly improved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9069E..1MY','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9069E..1MY"><span id="translatedtitle">Automatic extraction of power lines by <span class="hlt">particle</span> <span class="hlt">filtering</span> from aerial images</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ye, Famao; Li, Fuyu; Hu, Shihong</p> <p>2014-01-01</p> <p>In this paper an approach based on <span class="hlt">particle</span> <span class="hlt">filtering</span> to automatic extract power lines from aerial images is presented. We integrate the similarity of grey value of power lines into <span class="hlt">particle</span> <span class="hlt">filtering</span> to track the points on power lines, and use those extracted points to fit the power line as a parabola. Moreover, a fully automatic initialization strategy is used. Experimental results show that the proposed approach is a promising and fully automatic method for extracting power lines from very complex background. This algorithm will play an important role in the exact 3D-reconstructions of power lines that can help the power grid company to ensure the safety of the power lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020002861','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020002861"><span id="translatedtitle"><span class="hlt">Particle</span> <span class="hlt">Filters</span> for Real-Time Fault Detection in Planetary Rovers</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dearden, Richard; Clancy, Dan; Koga, Dennis (Technical Monitor)</p> <p>2001-01-01</p> <p>Planetary rovers provide a considerable challenge for robotic systems in that they must operate for long periods autonomously, or with relatively little intervention. To achieve this, they need to have on-board fault detection and diagnosis capabilities in order to determine the actual state of the vehicle, and decide what actions are safe to perform. Traditional model-based diagnosis techniques are not suitable for rovers due to the tight coupling between the vehicle's performance and its environment. Hybrid diagnosis using <span class="hlt">particle</span> <span class="hlt">filters</span> is presented as an alternative, and its strengths and weakeners are examined. We also present some extensions to <span class="hlt">particle</span> <span class="hlt">filters</span> that are designed to make them more suitable for use in diagnosis problems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9301E..1PZ','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9301E..1PZ"><span id="translatedtitle">A fast <span class="hlt">particle</span> <span class="hlt">filter</span> object tracking algorithm by dual features fusion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Shou-wei; Wang, Wei-ming; Ma, Sa-sa; Zhang, Yong; Yu, Ming</p> <p>2014-11-01</p> <p>Under the <span class="hlt">particle</span> <span class="hlt">filtering</span> framework, a video object tracking method described by dual cues extracting from integral histogram and integral image is proposed. The method takes both the color histogram feature and the Harr-like feature of the target region as the feature representation model, tracking the target region by <span class="hlt">particle</span> <span class="hlt">filter</span>. In the premise of ensuring the real-time responsiveness, it overcomes the shortcomings of poor precision, large fluctuations, light sensitive defects and so on by only relying on histogram feature tracking. It shows high efficiency by tracking the target object in multiple video sequences. Finally, it is applied in the augmented reality assisted maintenance prototype system, which proves that the method can be used in the tracking registration process of the augmented reality system based on natural feature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3871098','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3871098"><span id="translatedtitle">Unscented <span class="hlt">Particle</span> <span class="hlt">Filtering</span> for Estimation of Shipboard Deformation Based on Inertial Measurement Units</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Bo; Xiao, Xuan; Xia, Yuanqing; Fu, Mengyin</p> <p>2013-01-01</p> <p>Shipboard is not an absolute rigid body. Many factors could cause deformations which lead to large errors of mounted devices, especially for the navigation systems. Such errors should be estimated and compensated effectively, or they will severely reduce the navigation accuracy of the ship. In order to estimate the deformation, an unscented <span class="hlt">particle</span> <span class="hlt">filter</span> method for estimation of shipboard deformation based on an inertial measurement unit is presented. In this method, a nonlinear shipboard deformation model is built. Simulations demonstrated the accuracy reduction due to deformation. Then an attitude plus angular rate match mode is proposed as a frame to estimate the shipboard deformation using inertial measurement units. In this frame, for the nonlinearity of the system model, an unscented <span class="hlt">particle</span> <span class="hlt">filter</span> method is proposed to estimate and compensate the deformation angles. Simulations show that the proposed method gives accurate and rapid deformation estimations, which can increase navigation accuracy after compensation of deformation. PMID:24248280</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040087092','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040087092"><span id="translatedtitle">Combining <span class="hlt">Particle</span> <span class="hlt">Filters</span> and Consistency-Based Approaches for Monitoring and Diagnosis of Stochastic Hybrid Systems</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Narasimhan, Sriram; Dearden, Richard; Benazera, Emmanuel</p> <p>2004-01-01</p> <p>Fault detection and isolation are critical tasks to ensure correct operation of systems. When we consider stochastic hybrid systems, diagnosis algorithms need to track both the discrete mode and the continuous state of the system in the presence of noise. Deterministic techniques like Livingstone cannot deal with the stochasticity in the system and models. Conversely Bayesian belief update techniques such as <span class="hlt">particle</span> <span class="hlt">filters</span> may require many computational resources to get a good approximation of the true belief state. In this paper we propose a fault detection and isolation architecture for stochastic hybrid systems that combines look-ahead Rao-Blackwellized <span class="hlt">Particle</span> <span class="hlt">Filters</span> (RBPF) with the Livingstone 3 (L3) diagnosis engine. In this approach RBPF is used to track the nominal behavior, a novel n-step prediction scheme is used for fault detection and L3 is used to generate a set of candidates that are consistent with the discrepant observations which then continue to be tracked by the RBPF scheme.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21147325','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21147325"><span id="translatedtitle">An approach to measure trace elements in <span class="hlt">particles</span> collected on fiber <span class="hlt">filters</span> using EDXRF.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Oztürk, Fatma; Zararsiz, Abdullah; Kirmaz, Ridvan; Tuncel, Gürdal</p> <p>2011-01-15</p> <p>A method developed for analyzes of large number of aerosol samples using Energy Dispersive X-Ray Fluorescence (EDXRF) and its performance were discussed in this manuscript. Atmospheric aerosol samples evaluated in this study were collected on cellulose fiber (Whatman-41) <span class="hlt">filters</span>, employing a Hi-Vol sampler, at a monitoring station located on the Mediterranean coast of Turkey, between 1993 and 2001. Approximately 1700 samples were collected in this period. Six-hundred of these samples were analyzed by instrumental neutron activation (INAA), and the rest were archived. EDXRF was selected as an analytical technique to analyze 1700 aerosol samples because of its speed and non-destructive nature. However, analysis of aerosol samples collected on fiber <span class="hlt">filters</span> with a surface technique such as EDXRF was a challenge. Penetration depth calculation performed in this study revealed that EDXRF can obtain information from top 150μm of our fiber <span class="hlt">filter</span> material. Calibration of the instrument with currently available thin film standards caused unsatisfactory results since the actual penetration depth of <span class="hlt">particles</span> into fiber <span class="hlt">filters</span> were much deeper than 150μm. A method was developed in this manuscript to analyze fiber <span class="hlt">filter</span> samples quickly with XRF. Two hundred samples that were analyzed by INAA were divided into two equal batches. One of these batches was used to calibrate the XRF and the second batch was used for verification. The results showed that developed method can be reliably used for routine analysis of fiber samples loaded with ambient aerosol. PMID:21147325</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/835884','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/835884"><span id="translatedtitle">A HIGH TEMPERATURE TEST FACILITY FOR STUDYING ASH <span class="hlt">PARTICLE</span> CHARACTERISTICS OF CANDLE <span class="hlt">FILTER</span> DURING SURFACE REGENERATION</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kang, B.S-J.; Johnson, E.K.; Rincon, J.</p> <p>2002-09-19</p> <p>Hot gas particulate filtration is a basic component in advanced power generation systems such as Integrated Gasification Combined Cycle (IGCC) and Pressurized Fluidized Bed Combustion (PFBC). These systems require effective particulate removal to protect the downstream gas turbine and also to meet environmental emission requirements. The ceramic barrier <span class="hlt">filter</span> is one of the options for hot gas filtration. Hot gases flow through ceramic candle <span class="hlt">filters</span> leaving ash deposited on the outer surface of the <span class="hlt">filter</span>. A process known as surface regeneration removes the deposited ash periodically by using a high pressure back pulse cleaning jet. After this cleaning process has been done there may be some residual ash on the <span class="hlt">filter</span> surface. This residual ash may grow and this may lead to mechanical failure of the <span class="hlt">filter</span>. A High Temperature Test Facility (HTTF) was built to investigate the ash characteristics during surface regeneration at high temperatures. The system is capable of conducting surface regeneration tests of a single candle <span class="hlt">filter</span> at temperatures up to 1500 F. Details of the HTTF apparatus as well as some preliminary test results are presented in this paper. In order to obtain sequential digital images of ash <span class="hlt">particle</span> distribution during the surface regeneration process, a high resolution, high speed image acquisition system was integrated into the HTTF system. The regeneration pressure and the transient pressure difference between the inside of the candle <span class="hlt">filter</span> and the chamber during regeneration were measured using a high speed PC data acquisition system. The control variables for the high temperature regeneration tests were (1) face velocity, (2) pressure of the back pulse, and (3) cyclic ash built-up time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21413209','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21413209"><span id="translatedtitle"><span class="hlt">Optimal</span> configurations of <span class="hlt">filter</span> cavity in future gravitational-wave detectors</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Khalili, F. Ya.</p> <p>2010-06-15</p> <p>Sensitivity of future laser interferometric gravitational wave detectors can be improved using squeezed light with frequency-dependent squeeze angle and/or amplitude, which can be created using additional so-called <span class="hlt">filter</span> cavities. Here we compare performances of several variants of this scheme, proposed during the last few years, assuming the case of a single relatively short (tens of meters) <span class="hlt">filter</span> cavity suitable for implementation already during the life cycle of the second-generation detectors, like Advanced LIGO. Using numerical <span class="hlt">optimization</span>, we show that the phase <span class="hlt">filtering</span> scheme proposed by Kimble et al [H. J. Kimble, Yu. Levin, A. B. Matsko, K. S. Thorne, and S. P. Vyatchanin, Phys. Rev. D 65, 022002 (2001).] looks like the best candidate for this scenario.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ITEIS.132.1066T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ITEIS.132.1066T"><span id="translatedtitle">Design of FIR <span class="hlt">Filters</span> with Discrete Coefficients using Ant Colony <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsutsumi, Shuntaro; Suyama, Kenji</p> <p></p> <p>In this paper, we propose a new design method for linear phase FIR (Finite Impulse Response) <span class="hlt">filters</span> with discrete coefficients. In a hardware implementation, <span class="hlt">filter</span> coefficients must be represented as discrete values. The design problem of digital <span class="hlt">filters</span> with discrete coefficients is formulated as the integer programming problem. Then, an enormous amount of computational time is required to solve the problem in a strict solver. Recently, ACO (Ant Colony <span class="hlt">Optimization</span>) which is one heuristic approach, is used widely for solving combinational problem like the traveling salesman problem. In our method, we formulate the design problem as the 0-1 integer programming problem and solve it by using the ACO. Several design examples are shown to present effectiveness of the proposed method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009ITEIS.129...59O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009ITEIS.129...59O"><span id="translatedtitle"><span class="hlt">Optimal</span> Design of CSD Coefficient FIR <span class="hlt">Filters</span> Subject to Number of Nonzero Digits</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ozaki, Yuichi; Suyama, Kenji</p> <p></p> <p>In a hardware implementation of FIR(Finite Impulse Response) digital <span class="hlt">filters</span>, it is desired to reduce a total number of nonzero digits used for a representation of <span class="hlt">filter</span> coefficients. In general, a design problem of FIR <span class="hlt">filters</span> with CSD(Canonic Signed Digit) representation, which is efficient one for the reduction of numbers of multiplier units, is often considered as one of the 0-1 combinational problems. In such the problem, some difficult constraints make us prevent to linearize the problem. Although many kinds of heuristic approaches have been applied to solve the problem, the solution obtained by such a manner could not guarantee its <span class="hlt">optimality</span>. In this paper, we attempt to formulate the design problem as the 0-1 mixed integer linear programming problem and solve it by using the branch and bound technique, which is a powerful method for solving integer programming problem. Several design examples are shown to present an efficient performance of the proposed method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15885419','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15885419"><span id="translatedtitle">The effect of ash and <span class="hlt">filter</span> media characteristics on <span class="hlt">particle</span> filtration efficiency in fluidized bed.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wey, Ming-Yen; Chen, Ke-Hao; Liu, Kuang-Yu</p> <p>2005-05-20</p> <p>The phenomenon of <span class="hlt">filtering</span> <span class="hlt">particles</span> by a fluidized bed is complex and the parameters that affect the control efficiency of filtration have not yet been clarified. The major objective of the study focuses on the effect of characteristics of ash and <span class="hlt">filter</span> media on filtration efficiency in a fluidized bed. The performance of the fluidized bed for removal of <span class="hlt">particles</span> in flue gas at various fluidized operating conditions, and then the mechanisms of collecting <span class="hlt">particles</span> were studied. The evaluated parameters included (1) various ashes (coal ash and incinerator ash); (2) bed material size; (3) operating gas velocity; and (4) bed temperature. The results indicate that the removal efficiency of coal ash increases initially with gas velocity, then decreases gradually as velocity exceeds some specific value. Furthermore, the removal of coal ash enhance with silica sand size decreasing. When the fluidized bed is operated at high temperature, diffusion is a more important mechanism than at room temperature especially for small <span class="hlt">particles</span>. Although the inertial impaction is the main collection mechanism, the "bounce off" effect when the <span class="hlt">particles</span> collide with the bed material could reduce the removal efficiency significantly. Because of layer inversion in fluidized bed, the removal efficiency of incinerator ash is decreased with increasing of gas velocity. PMID:15885419</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22285035','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22285035"><span id="translatedtitle"><span class="hlt">Particles</span> in swimming pool <span class="hlt">filters</span>--does pH determine the DBP formation?</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hansen, Kamilla M S; Willach, Sarah; Mosbæk, Hans; Andersen, Henrik R</p> <p>2012-04-01</p> <p>The formation was investigated for different groups of disinfection byproducts (DBPs) during chlorination of <span class="hlt">filter</span> <span class="hlt">particles</span> from swimming pools at different pH-values and the toxicity was estimated. Specifically, the formation of the DBP group trihalomethanes (THMs), which is regulated in many countries, and the non-regulated haloacetic acids (HAAs) and haloacetonitriles (HANs) were investigated at 6.0≤pH≤8.0, under controlled chlorination conditions. The investigated <span class="hlt">particles</span> were collected from a hot tub with a drum micro <span class="hlt">filter</span>. In two series of experiments with either constant initial active or initial free chlorine concentrations the <span class="hlt">particles</span> were chlorinated at different pH-values in the relevant range for swimming pools. THM and HAA formations were reduced by decreasing pH while HAN formation increased with decreasing pH. Based on the organic content the relative DBP formation from the <span class="hlt">particles</span> was higher than previously reported for body fluid analogue and filling water. The genotoxicity and cytotoxicity estimated from formation of DBPs from the treated <span class="hlt">particle</span> suspension increased with decreasing pH. Among the quantified DBP groups the HANs were responsible for the majority of the toxicity from the measured DBPs. PMID:22285035</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009IEITF..92.2801S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009IEITF..92.2801S"><span id="translatedtitle">Hardware Accelerator for Run-Time Learning Adopted in Object Recognition with Cascade <span class="hlt">Particle</span> <span class="hlt">Filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sugano, Hiroki; Ochi, Hiroyuki; Nakamura, Yukihiro; Miyamoto, Ryusuke</p> <p></p> <p>Recently, many researchers tackle accurate object recognition algorithms and many algorithms are proposed. However, these algorithms have some problems caused by variety of real environments such as a direction change of the object or its shading change. The new tracking algorithm, Cascade <span class="hlt">Particle</span> <span class="hlt">Filter</span>, is proposed to fill such demands in real environments by constructing the object model while tracking the objects. We have been investigating to implement accurate object recognition on embedded systems in real-time. In order to apply the Cascade <span class="hlt">Particle</span> <span class="hlt">Filter</span> to embedded applications such as surveillance, automotives, and robotics, a hardware accelerator is indispensable because of limitations in power consumption. In this paper we propose a hardware implementation of the Discrete AdaBoost algorithm that is the most computationally intensive part of the Cascade <span class="hlt">Particle</span> <span class="hlt">Filter</span>. To implement the proposed hardware, we use PICO Express, a high level synthesis tool provided by Synfora, for rapid prototyping. Implementation result shows that the synthesized hardware has 1, 132, 038 transistors and the die area is 2,195µm × 1,985µm under a 0.180µm library. The simulation result shows that total processing time is about 8.2 milliseconds at 65MHz operation frequency.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25192318','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25192318"><span id="translatedtitle">Robust dead reckoning system for mobile robots based on <span class="hlt">particle</span> <span class="hlt">filter</span> and raw range scan.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Duan, Zhuohua; Cai, Zixing; Min, Huaqing</p> <p>2014-01-01</p> <p>Robust dead reckoning is a complicated problem for wheeled mobile robots (WMRs), where the robots are faulty, such as the sticking of sensors or the slippage of wheels, for the discrete fault models and the continuous states have to be estimated simultaneously to reach a reliable fault diagnosis and accurate dead reckoning. <span class="hlt">Particle</span> <span class="hlt">filters</span> are one of the most promising approaches to handle hybrid system estimation problems, and they have also been widely used in many WMRs applications, such as pose tracking, SLAM, video tracking, fault identification, etc. In this paper, the readings of a laser range finder, which may be also interfered with by noises, are used to reach accurate dead reckoning. The main contribution is that a systematic method to implement fault diagnosis and dead reckoning in a <span class="hlt">particle</span> <span class="hlt">filter</span> framework concurrently is proposed. Firstly, the perception model of a laser range finder is given, where the raw scan may be faulty. Secondly, the kinematics of the normal model and different fault models for WMRs are given. Thirdly, the <span class="hlt">particle</span> <span class="hlt">filter</span> for fault diagnosis and dead reckoning is discussed. At last, experiments and analyses are reported to show the accuracy and efficiency of the presented method. PMID:25192318</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4208186','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4208186"><span id="translatedtitle">Robust Dead Reckoning System for Mobile Robots Based on <span class="hlt">Particle</span> <span class="hlt">Filter</span> and Raw Range Scan</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Duan, Zhuohua; Cai, Zixing; Min, Huaqing</p> <p>2014-01-01</p> <p>Robust dead reckoning is a complicated problem for wheeled mobile robots (WMRs), where the robots are faulty, such as the sticking of sensors or the slippage of wheels, for the discrete fault models and the continuous states have to be estimated simultaneously to reach a reliable fault diagnosis and accurate dead reckoning. <span class="hlt">Particle</span> <span class="hlt">filters</span> are one of the most promising approaches to handle hybrid system estimation problems, and they have also been widely used in many WMRs applications, such as pose tracking, SLAM, video tracking, fault identification, etc. In this paper, the readings of a laser range finder, which may be also interfered with by noises, are used to reach accurate dead reckoning. The main contribution is that a systematic method to implement fault diagnosis and dead reckoning in a <span class="hlt">particle</span> <span class="hlt">filter</span> framework concurrently is proposed. Firstly, the perception model of a laser range finder is given, where the raw scan may be faulty. Secondly, the kinematics of the normal model and different fault models for WMRs are given. Thirdly, the <span class="hlt">particle</span> <span class="hlt">filter</span> for fault diagnosis and dead reckoning is discussed. At last, experiments and analyses are reported to show the accuracy and efficiency of the presented method. PMID:25192318</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009MSSP...23..652C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009MSSP...23..652C"><span id="translatedtitle"><span class="hlt">Optimal</span> <span class="hlt">filtering</span> of gear signals for early damage detection based on the spectral kurtosis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Combet, F.; Gelman, L.</p> <p>2009-04-01</p> <p>In this paper, we propose a methodology for the enhancement of small transients in gear vibration signals in order to detect local tooth faults, such as pitting, at an early stage of damage. We propose to apply the <span class="hlt">optimal</span> denoising (Wiener) <span class="hlt">filter</span> based on the spectral kurtosis (SK). The originality is to estimate and apply this <span class="hlt">filter</span> to the gear residual signal, as classically obtained after removing the mesh harmonics from the time synchronous average (TSA). This presents several advantages over the direct estimation from the raw vibration signal: improved signal/noise ratio, reduced interferences from other stages of the gearbox and easier detection of excited structural resonance(s) within the range of the mesh harmonic components. From the SK-based <span class="hlt">filtered</span> residual signal, called SK-residual, we define the local power as the smoothed squared envelope, which reflects both the energy and the degree of non-stationarity of the fault-induced transients. The methodology is then applied to an industrial case and shows the possibility of detection of relatively small tooth surface pitting (less than 10%) in a two-stage helical reduction gearbox. The adjustment of the resolution for the SK estimation appears to be <span class="hlt">optimal</span> when the length of the analysis window is approximately matched with the mesh period of the gear. The proposed approach is also compared to an inverse <span class="hlt">filtering</span> (blind deconvolution) approach. However, the latter turns out to be more unstable and sensitive to noise and shows a lower degree of separation, quantified by the Fisher criterion, between the estimated diagnostic features in the pitted and unpitted cases. Thus, the proposed <span class="hlt">optimal</span> <span class="hlt">filtering</span> methodology based on the SK appears to be well adapted for the early detection of local tooth damage in gears.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21396177','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21396177"><span id="translatedtitle">Multiobjective <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> for the <span class="hlt">optimal</span> design of photovoltaic grid-connected systems</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kornelakis, Aris</p> <p>2010-12-15</p> <p><span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) is a highly efficient evolutionary <span class="hlt">optimization</span> algorithm. In this paper a multiobjective <span class="hlt">optimization</span> algorithm based on PSO applied to the <span class="hlt">optimal</span> design of photovoltaic grid-connected systems (PVGCSs) is presented. The proposed methodology intends to suggest the <span class="hlt">optimal</span> number of system devices and the <span class="hlt">optimal</span> PV module installation details, such that the economic and environmental benefits achieved during the system's operational lifetime period are both maximized. The objective function describing the economic benefit of the proposed <span class="hlt">optimization</span> process is the lifetime system's total net profit which is calculated according to the method of the Net Present Value (NPV). The second objective function, which corresponds to the environmental benefit, equals to the pollutant gas emissions avoided due to the use of the PVGCS. The <span class="hlt">optimization</span>'s decision variables are the <span class="hlt">optimal</span> number of the PV modules, the PV modules <span class="hlt">optimal</span> tilt angle, the <span class="hlt">optimal</span> placement of the PV modules within the available installation area and the <span class="hlt">optimal</span> distribution of the PV modules among the DC/AC converters. (author)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950028531&hterms=discrimination&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Ddiscrimination','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950028531&hterms=discrimination&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Ddiscrimination"><span id="translatedtitle"><span class="hlt">Optimizing</span> binary phase and amplitude <span class="hlt">filters</span> for PCE, SNR, and discrimination</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Downie, John D.</p> <p>1992-01-01</p> <p>Binary phase-only <span class="hlt">filters</span> (BPOFs) have generated much study because of their implementation on currently available spatial light modulator devices. On polarization-rotating devices such as the magneto-optic spatial light modulator (SLM), it is also possible to encode binary amplitude information into two SLM transmission states, in addition to the binary phase information. This is done by varying the rotation angle of the polarization analyzer following the SLM in the optical train. Through this parameter, a continuum of <span class="hlt">filters</span> may be designed that span the space of binary phase and amplitude <span class="hlt">filters</span> (BPAFs) between BPOFs and binary amplitude <span class="hlt">filters</span>. In this study, we investigate the design of <span class="hlt">optimal</span> BPAFs for the key correlation characteristics of peak sharpness (through the peak-to-correlation energy (PCE) metric), signal-to-noise ratio (SNR), and discrimination between in-class and out-of-class images. We present simulation results illustrating improvements obtained over conventional BPOFs, and trade-offs between the different performance criteria in terms of the <span class="hlt">filter</span> design parameter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000053101','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000053101"><span id="translatedtitle">Multi-Bandwidth Frequency Selective Surfaces for Near Infrared <span class="hlt">Filtering</span>: Design and <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cwik, Tom; Fernandez, Salvador; Ksendzov, A.; LaBaw, Clayton C.; Maker, Paul D.; Muller, Richard E.</p> <p>1998-01-01</p> <p>Frequency selective surfaces are widely used in the microwave and millimeter wave regions of the spectrum for <span class="hlt">filtering</span> signals. They are used in telecommunication systems for multi-frequency operation or in instrument detectors for spectroscopy. The frequency selective surface operation depends on a periodic array of elements resonating at prescribed wavelengths producing a <span class="hlt">filter</span> response. The size of the elements is on the order of half the electrical wavelength, and the array period is typically less than a wavelength for efficient operation. When operating in the optical region, diffraction gratings are used for <span class="hlt">filtering</span>. In this regime the period of the grating may be several wavelengths producing multiple orders of light in reflection or transmission. In regions between these bands (specifically in the infrared band) frequency selective <span class="hlt">filters</span> consisting of patterned metal layers fabricated using electron beam lithography are beginning to be developed. The operation is completely analogous to surfaces made in the microwave and millimeter wave region except for the choice of materials used and the fabrication process. In addition, the lithography process allows an arbitrary distribution of patterns corresponding to resonances at various wavelengths to be produced. The design of sub-millimeter <span class="hlt">filters</span> follows the design methods used in the microwave region. Exacting modal matching, integral equation or finite element methods can be used for design. A major difference though is the introduction of material parameters and thicknesses that may not be important in longer wavelength designs. This paper describes the design of multi- bandwidth <span class="hlt">filters</span> operating in the 1-5 micrometer wavelength range. This work follows on a previous design. In this paper extensions based on further <span class="hlt">optimization</span> and an examination of the specific shape of the element in the periodic cell will be reported. Results from the design, manufacture and test of linear wedge <span class="hlt">filters</span> built using microlithographic techniques and used in spectral imaging applications will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20050123787&hterms=selective+surface&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dselective%2Bsurface','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20050123787&hterms=selective+surface&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dselective%2Bsurface"><span id="translatedtitle">Multi-Bandwidth Frequency Selective Surfaces for Near Infrared <span class="hlt">Filtering</span>: Design and <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cwik, Tom; Fernandez, Salvador; Ksendzov, A.; LaBaw, Clayton C.; Maker, Paul D.; Muller, Richard E.</p> <p>1999-01-01</p> <p>Frequency selective surfaces are widely used in the microwave and millimeter wave regions of the spectrum for <span class="hlt">filtering</span> signals. They are used in telecommunication systems for multi-frequency operation or in instrument detectors for spectroscopy. The frequency selective surface operation depends on a periodic array of elements resonating at prescribed wavelengths producing a <span class="hlt">filter</span> response. The size of the elements is on the order of half the electrical wavelength, and the array period is typically less than a wavelength for efficient operation. When operating in the optical region, diffraction gratings are used for <span class="hlt">filtering</span>. In this regime the period of the grating may be several wavelengths producing multiple orders of light in reflection or transmission. In regions between these bands (specifically in the infrared band) frequency selective <span class="hlt">filters</span> consisting of patterned metal layers fabricated using electron beam lithography are beginning to be developed. The operation is completely analogous to surfaces made in the microwave and millimeter wave region except for the choice of materials used and the fabrication process. In addition, the lithography process allows an arbitrary distribution of patterns corresponding to resonances at various wavelengths to be produced. The design of sub-millimeter <span class="hlt">filters</span> follows the design methods used in the microwave region. Exacting modal matching, integral equation or finite element methods can be used for design. A major difference though is the introduction of material parameters and thicknesses tha_ may not be important in longer wavelength designs. This paper describes the design of multi-bandwidth <span class="hlt">filters</span> operating in the I-5 micrometer wavelength range. This work follows on previous design [1,2]. In this paper extensions based on further <span class="hlt">optimization</span> and an examination of the specific shape of the element in the periodic cell will be reported. Results from the design, manufacture and test of linear wedge <span class="hlt">filters</span> built using micro-lithographic techniques and used ir spectral imaging applications will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23796954','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23796954"><span id="translatedtitle"><span class="hlt">Optimization</span> of adenovirus 40 and 41 recovery from tap water using small disk <span class="hlt">filters</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McMinn, Brian R</p> <p>2013-11-01</p> <p>Currently, the U.S. Environmental Protection Agency's Information Collection Rule (ICR) for the primary concentration of viruses from drinking and surface waters uses the 1MDS <span class="hlt">filter</span>, but a more cost effective option, the NanoCeram® <span class="hlt">filter</span>, has been shown to recover comparable levels of enterovirus and norovirus from both matrices. In order to achieve the highest viral recoveries, filtration methods require the identification of <span class="hlt">optimal</span> concentration conditions that are unique for each virus type. This study evaluated the effectiveness of 1MDS and NanoCeram <span class="hlt">filters</span> in recovering adenovirus (AdV) 40 and 41 from tap water, and <span class="hlt">optimized</span> two secondary concentration procedures the celite and organic flocculation method. Adjustments in pH were made to both virus elution solutions and sample matrices to determine which resulted in higher virus recovery. Samples were analyzed by quantitative PCR (qPCR) and Most Probable Number (MPN) techniques and AdV recoveries were determined by comparing levels of virus in sample concentrates to that in the initial input. The recovery of adenovirus was highest for samples in unconditioned tap water (pH 8) using the 1MDS <span class="hlt">filter</span> and celite for secondary concentration. Elution buffer containing 0.1% sodium polyphosphate at pH 10.0 was determined to be most effective overall for both AdV types. Under these conditions, the average recovery for AdV40 and 41 was 49% and 60%, respectively. By <span class="hlt">optimizing</span> secondary elution steps, AdV recovery from tap water could be improved at least two-fold compared to the currently used methodology. Identification of the <span class="hlt">optimal</span> concentration conditions for human AdV (HAdV) is important for timely and sensitive detection of these viruses from both surface and drinking waters. PMID:23796954</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JBO....20e5003W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JBO....20e5003W"><span id="translatedtitle"><span class="hlt">Optimal</span> spectral <span class="hlt">filtering</span> in soliton self-frequency shift for deep-tissue multiphoton microscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Ke; Qiu, Ping</p> <p>2015-05-01</p> <p>Tunable optical solitons generated by soliton self-frequency shift (SSFS) have become valuable tools for multiphoton microscopy (MPM). Recent progress in MPM using 1700 nm excitation enabled visualizing subcortical structures in mouse brain in vivo for the first time. Such an excitation source can be readily obtained by SSFS in a large effective-mode-area photonic crystal rod with a 1550-nm fiber femtosecond laser. A longpass <span class="hlt">filter</span> was typically used to isolate the soliton from the residual in order to avoid excessive energy deposit on the sample, which ultimately leads to optical damage. However, since the soliton was not cleanly separated from the residual, the criterion for choosing the <span class="hlt">optimal</span> <span class="hlt">filtering</span> wavelength is lacking. Here, we propose maximizing the ratio between the multiphoton signal and the n'th power of the excitation pulse energy as a criterion for <span class="hlt">optimal</span> spectral <span class="hlt">filtering</span> in SSFS when the soliton shows dramatic overlapping with the residual. This <span class="hlt">optimization</span> is based on the most efficient signal generation and entirely depends on physical quantities that can be easily measured experimentally. Its application to MPM may reduce tissue damage, while maintaining high signal levels for efficient deep penetration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhFl...24h3302S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhFl...24h3302S"><span id="translatedtitle">Inertial <span class="hlt">particle</span> acceleration statistics in turbulence: Effects of <span class="hlt">filtering</span>, biased sampling, and flow topology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salazar, Juan P. L. C.; Collins, Lance R.</p> <p>2012-08-01</p> <p>In this study, we investigate the effect of "biased sampling," i.e., the clustering of inertial <span class="hlt">particles</span> in regions of the flow with low vorticity, and "<span class="hlt">filtering</span>," i.e., the tendency of inertial <span class="hlt">particles</span> to attenuate the fluid velocity fluctuations, on the probability density function of inertial <span class="hlt">particle</span> accelerations. In particular, we find that the concept of "biased <span class="hlt">filtering</span>" introduced by Ayyalasomayajula et al. ["Modeling inertial <span class="hlt">particle</span> acceleration statistics in isotropic turbulence," Phys. Fluids 20, 0945104 (2008), 10.1063/1.2976174], in which <span class="hlt">particles</span> <span class="hlt">filter</span> stronger acceleration events more than weaker ones, is relevant to the higher order moments of acceleration. Flow topology and its connection to acceleration is explored through invariants of the velocity-gradient, strain-rate, and rotation-rate tensors. A semi-quantitative analysis is performed where we assess the contribution of specific flow topologies to acceleration moments. Our findings show that the contributions of regions of high vorticity and low strain decrease significantly with Stokes number, a non-dimensional measure of <span class="hlt">particle</span> inertia. The contribution from regions of low vorticity and high strain exhibits a peak at a Stokes number of approximately 0.2. Following the methodology of Ooi et al. ["A study of the evolution and characteristics of the invariants of the velocity-gradient tensor in isotropic turbulence," J. Fluid Mech. 381, 141 (1999), 10.1017/S0022112098003681], we compute mean conditional trajectories in planes formed by pairs of tensor invariants in time. Among the interesting findings is the existence of a stable focus in the plane formed by the second invariants of the strain-rate and rotation-rate tensors. Contradicting the results of Ooi et al., we find a stable focus in the plane formed by the second and third invariants of the strain-rate tensor for fluid tracers. We confirm, at an even higher Reynolds number, the conjecture of Collins and Keswani ["Reynolds number scaling of <span class="hlt">particle</span> clustering in turbulent aerosols," New J. Phys. 6, 119 (2004), 10.1088/1367-2630/6/1/119] that inertial <span class="hlt">particle</span> clustering saturates at large Reynolds numbers. The result is supported by the theory presented in Chun et al. ["Clustering of aerosol <span class="hlt">particles</span> in isotropic turbulence," J. Fluid Mech. 536, 219 (2005), 10.1017/S0022112005004568].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......124J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......124J"><span id="translatedtitle">Multivariable <span class="hlt">optimization</span> of liquid rocket engines using <span class="hlt">particle</span> swarm algorithms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jones, Daniel Ray</p> <p></p> <p>Liquid rocket engines are highly reliable, controllable, and efficient compared to other conventional forms of rocket propulsion. As such, they have seen wide use in the space industry and have become the standard propulsion system for launch vehicles, orbit insertion, and orbital maneuvering. Though these systems are well understood, historical <span class="hlt">optimization</span> techniques are often inadequate due to the highly non-linear nature of the engine performance problem. In this thesis, a <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) variant was applied to maximize the specific impulse of a finite-area combustion chamber (FAC) equilibrium flow rocket performance model by controlling the engine's oxidizer-to-fuel ratio and de Laval nozzle expansion and contraction ratios. In addition to the PSO-controlled parameters, engine performance was calculated based on propellant chemistry, combustion chamber pressure, and ambient pressure, which are provided as inputs to the program. The performance code was validated by comparison with NASA's Chemical Equilibrium with Applications (CEA) and the commercially available Rocket Propulsion Analysis (RPA) tool. Similarly, the PSO algorithm was validated by comparison with brute-force <span class="hlt">optimization</span>, which calculates all possible solutions and subsequently determines which is the optimum. <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> was shown to be an effective <span class="hlt">optimizer</span> capable of quick and reliable convergence for complex functions of multiple non-linear variables.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23713673','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23713673"><span id="translatedtitle">PCDD/F formation in an iron/potassium-catalyzed diesel <span class="hlt">particle</span> <span class="hlt">filter</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Heeb, Norbert V; Zennegg, Markus; Haag, Regula; Wichser, Adrian; Schmid, Peter; Seiler, Cornelia; Ulrich, Andrea; Honegger, Peter; Zeyer, Kerstin; Emmenegger, Lukas; Bonsack, Peter; Zimmerli, Yan; Czerwinski, Jan; Kasper, Markus; Mayer, Andreas</p> <p>2013-06-18</p> <p>Catalytic diesel <span class="hlt">particle</span> <span class="hlt">filters</span> (DPFs) have evolved to a powerful environmental technology. Several metal-based, fuel soluble catalysts, so-called fuel-borne catalysts (FBCs), were developed to catalyze soot combustion and support <span class="hlt">filter</span> regeneration. Mainly iron- and cerium-based FBCs have been commercialized for passenger cars and heavy-duty vehicle applications. We investigated a new iron/potassium-based FBC used in combination with an uncoated silicon carbide <span class="hlt">filter</span> and report effects on emissions of polychlorinated dibenzodioxins/furans (PCDD/Fs). The PCDD/F formation potential was assessed under best and worst case conditions, as required for <span class="hlt">filter</span> approval under the VERT protocol. TEQ-weighted PCDD/F emissions remained low when using the Fe/K catalyst (37/7.5 μg/g) with the <span class="hlt">filter</span> and commercial, low-sulfur fuel. The addition of chlorine (10 μg/g) immediately led to an intense PCDD/F formation in the Fe/K-DPF. TEQ-based emissions increased 51-fold from engine-out levels of 95 to 4800 pg I-TEQ/L after the DPF. Emissions of 2,3,7,8-TCDD, the most toxic congener (TEF = 1.0), increased 320-fold, those of 2,3,7,8-TCDF (TEF = 0.1) even 540-fold. Remarkable pattern changes were noticed, indicating a preferential formation of tetrachlorinated dibenzofurans. It has been shown that potassium acts as a structural promoter inducing the formation of magnetite (Fe3O4) rather than hematite (Fe2O3). This may alter the catalytic properties of iron. But the chemical nature of this new catalyst is yet unknown, and we are far from an established mechanism for this new pathway to PCDD/Fs. In conclusion, the iron/potassium-catalyzed DPF has a high PCDD/F formation potential, similar to the ones of copper-catalyzed <span class="hlt">filters</span>, the latter are prohibited by Swiss legislation. PMID:23713673</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AcAau.113..149H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AcAau.113..149H"><span id="translatedtitle"><span class="hlt">Optimal</span> satellite formation reconfiguration using co-evolutionary <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> in deep space</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huang, Haibin; Zhuang, Yufei</p> <p>2015-08-01</p> <p>This paper proposes a method that plans energy-<span class="hlt">optimal</span> trajectories for multi-satellite formation reconfiguration in deep space environment. A novel co-evolutionary <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> algorithm is stated to solve the nonlinear programming problem, so that the computational complexity of calculating the gradient information could be avoided. One swarm represents one satellite, and through communication with other swarms during the evolution, collisions between satellites can be avoided. In addition, a dynamic depth first search algorithm is proposed to solve the redundant search problem of a co-evolutionary <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> method, with which the computation time can be shorten a lot. In order to make the actual trajectories <span class="hlt">optimal</span> and collision-free with disturbance, a re-planning strategy is deduced for formation reconfiguration maneuver.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AIPC.1052..116O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AIPC.1052..116O"><span id="translatedtitle"><span class="hlt">Optimal</span> Pid Tuning for Power System Stabilizers Using Adaptive <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> Technique</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oonsivilai, Anant; Marungsri, Boonruang</p> <p>2008-10-01</p> <p>An application of the intelligent search technique to find <span class="hlt">optimal</span> parameters of power system stabilizer (PSS) considering proportional-integral-derivative controller (PID) for a single-machine infinite-bus system is presented. Also, an efficient intelligent search technique, adaptive <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (APSO), is engaged to express usefulness of the intelligent search techniques in tuning of the PID—PSS parameters. Improve damping frequency of system is <span class="hlt">optimized</span> by minimizing an objective function with adaptive <span class="hlt">particle</span> swarm <span class="hlt">optimization</span>. At the same operating point, the PID—PSS parameters are also tuned by the Ziegler-Nichols method. The performance of proposed controller compared to the conventional Ziegler-Nichols PID tuning controller. The results reveal superior effectiveness of the proposed APSO based PID controller.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2683099','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2683099"><span id="translatedtitle"><span class="hlt">Filter</span> feeders and plankton increase <span class="hlt">particle</span> encounter rates through flow regime control</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Humphries, Stuart</p> <p>2009-01-01</p> <p>Collisions between <span class="hlt">particles</span> or between <span class="hlt">particles</span> and other objects are fundamental to many processes that we take for granted. They drive the functioning of aquatic ecosystems, the onset of rain and snow precipitation, and the manufacture of pharmaceuticals, powders and crystals. Here, I show that the traditional assumption that viscosity dominates these situations leads to consistent and large-scale underestimation of encounter rates between <span class="hlt">particles</span> and of deposition rates on surfaces. Numerical simulations reveal that the encounter rate is Reynolds number dependent and that encounter efficiencies are consistent with the sparse experimental data. This extension of aerosol theory has great implications for understanding of selection pressure on the physiology and ecology of organisms, for example <span class="hlt">filter</span> feeders able to gather food at rates up to 5 times higher than expected. I provide evidence that <span class="hlt">filter</span> feeders have been strongly selected to take advantage of this flow regime and show that both the predicted peak concentration and the steady-state concentrations of plankton during blooms are ≈33% of that predicted by the current models of <span class="hlt">particle</span> encounter. Many ecological and industrial processes may be operating at substantially greater rates than currently assumed. PMID:19416879</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=48142&keyword=Radioactivity&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=72993233&CFTOKEN=53175719','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=48142&keyword=Radioactivity&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=72993233&CFTOKEN=53175719"><span id="translatedtitle">USE OF AN INERT RADIOACTIVE <span class="hlt">PARTICLE</span> FOR MEASURING <span class="hlt">PARTICLE</span> ACCUMULATION BY <span class="hlt">FILTER</span>-FEEDING BIVALVE MOLLUSCS</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The use of an inert, radioactively labeled microsphere as a measure of <span class="hlt">particle</span> accumulation (filtration activity) by Mulinia lateralis (Say) and Mytilus edulis L. was evaluated. Bottom sediment plus temperature and salinity of the water were varied to induce changes in filtratio...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015FlDyR..47e1404C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015FlDyR..47e1404C"><span id="translatedtitle">A <span class="hlt">particle</span> <span class="hlt">filter</span> to reconstruct a free-surface flow from a depth camera</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Combés, Benoit; Heitz, Dominique; Guibert, Anthony; Mémin, Etienne</p> <p>2015-10-01</p> <p>We investigate the combined use of a kinect depth sensor and of a stochastic data assimilation (DA) method to recover free-surface flows. More specifically, we use a weighted ensemble Kalman <span class="hlt">filter</span> method to reconstruct the complete state of free-surface flows from a sequence of depth images only. This <span class="hlt">particle</span> <span class="hlt">filter</span> accounts for model and observations errors. This DA scheme is enhanced with the use of two observations instead of one classically. We evaluate the developed approach on two numerical test cases: a collapse of a water column as a toy-example and a flow in an suddenly expanding flume as a more realistic flow. The robustness of the method to depth data errors and also to initial and inflow conditions is considered. We illustrate the interest of using two observations instead of one observation into the correction step, especially for unknown inflow boundary conditions. Then, the performance of the Kinect sensor in capturing the temporal sequences of depth observations is investigated. Finally, the efficiency of the algorithm is qualified for a wave in a real rectangular flat bottomed tank. It is shown that for basic initial conditions, the <span class="hlt">particle</span> <span class="hlt">filter</span> rapidly and remarkably reconstructs the velocity and height of the free surface flow based on noisy measurements of the elevation alone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24342270','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24342270"><span id="translatedtitle">Cascaded Kalman and <span class="hlt">particle</span> <span class="hlt">filters</span> for photogrammetry based gyroscope drift and robot attitude estimation.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sadaghzadeh N, Nargess; Poshtan, Javad; Wagner, Achim; Nordheimer, Eugen; Badreddin, Essameddin</p> <p>2014-03-01</p> <p>Based on a cascaded Kalman-<span class="hlt">Particle</span> <span class="hlt">Filtering</span>, gyroscope drift and robot attitude estimation method is proposed in this paper. Due to noisy and erroneous measurements of MEMS gyroscope, it is combined with Photogrammetry based vision navigation scenario. Quaternions kinematics and robot angular velocity dynamics with augmented drift dynamics of gyroscope are employed as system state space model. Nonlinear attitude kinematics, drift and robot angular movement dynamics each in 3 dimensions result in a nonlinear high dimensional system. To reduce the complexity, we propose a decomposition of system to cascaded subsystems and then design separate cascaded observers. This design leads to an easier tuning and more precise debugging from the perspective of programming and such a setting is well suited for a cooperative modular system with noticeably reduced computation time. Kalman <span class="hlt">Filtering</span> (KF) is employed for the linear and Gaussian subsystem consisting of angular velocity and drift dynamics together with gyroscope measurement. The estimated angular velocity is utilized as input of the second <span class="hlt">Particle</span> <span class="hlt">Filtering</span> (PF) based observer in two scenarios of stochastic and deterministic inputs. Simulation results are provided to show the efficiency of the proposed method. Moreover, the experimental results based on data from a 3D MEMS IMU and a 3D camera system are used to demonstrate the efficiency of the method. PMID:24342270</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhRvE..89b2726V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhRvE..89b2726V"><span id="translatedtitle"><span class="hlt">Optimal</span> estimation of diffusion coefficients from single-<span class="hlt">particle</span> trajectories</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vestergaard, Christian L.; Blainey, Paul C.; Flyvbjerg, Henrik</p> <p>2014-02-01</p> <p>How does one <span class="hlt">optimally</span> determine the diffusion coefficient of a diffusing <span class="hlt">particle</span> from a single-time-lapse recorded trajectory of the <span class="hlt">particle</span>? We answer this question with an explicit, unbiased, and practically <span class="hlt">optimal</span> covariance-based estimator (CVE). This estimator is regression-free and is far superior to commonly used methods based on measured mean squared displacements. In experimentally relevant parameter ranges, it also outperforms the analytically intractable and computationally more demanding maximum likelihood estimator (MLE). For the case of diffusion on a flexible and fluctuating substrate, the CVE is biased by substrate motion. However, given some long time series and a substrate under some tension, an extended MLE can separate <span class="hlt">particle</span> diffusion on the substrate from substrate motion in the laboratory frame. This provides benchmarks that allow removal of bias caused by substrate fluctuations in CVE. The resulting unbiased CVE is <span class="hlt">optimal</span> also for short time series on a fluctuating substrate. We have applied our estimators to human 8-oxoguanine DNA glycolase proteins diffusing on flow-stretched DNA, a fluctuating substrate, and found that diffusion coefficients are severely overestimated if substrate fluctuations are not accounted for.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1009716','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1009716"><span id="translatedtitle"><span class="hlt">Optimizing</span> Magnetite Nanoparticles for Mass Sensitivity in Magnetic <span class="hlt">Particle</span> Imaging</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ferguson, R Matthew; Minard, Kevin R; Khandhar, Amit P; Krishnan, Kannan M</p> <p>2011-03-01</p> <p>Purpose: Magnetic <span class="hlt">particle</span> imaging (MPI), using magnetite nanoparticles (MNPs) as tracer material, shows great promise as a platform for fast tomographic imaging. To date, the magnetic properties of MNPs used in imaging have not been <span class="hlt">optimized</span>. As nanoparticle magnetism shows strong size dependence, we explore how varying MNP size impacts imaging performance in order to determine <span class="hlt">optimal</span> MNP characteristics for MPI at any driving field frequency f<sub>0</sub>. Methods: Monodisperse MNPs of varying size were synthesized and their magnetic properties characterized. Their MPI response was measured experimentally, at an arbitrarily chosen f<sub>0</sub> = 250 kHz, using a custom-built MPI transceiver designed to detect the third harmonic of MNP magnetization. Results were interpreted using a model of dynamic MNP magnetization that is based on the Langevin theory of superparamagnetism and accounts for sample size distribution, and size-dependent magnetic relaxation. Results: Our experimental results show clear variation in the MPI signal intensity as a function of MNP size that is in good agreement with modeled results. A maxima in the plot of MPI signal vs. MNP size indicates there is a particular size that is <span class="hlt">optimal</span> for the chosen frequency of 250 kHz. Conclusions: For MPI at any chosen frequency, there will exist a characteristic <span class="hlt">particle</span> size that generates maximum signal amplitude. We illustrate this at 250 kHz with <span class="hlt">particles</span> of 15 nm core diameter.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4499655','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4499655"><span id="translatedtitle">Designing Artificial Neural Networks Using <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> Algorithms</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Garro, Beatriz A.; Vázquez, Roberto A.</p> <p>2015-01-01</p> <p>Artificial Neural Network (ANN) design is a complex task because its performance depends on the architecture, the selected transfer function, and the learning algorithm used to train the set of synaptic weights. In this paper we present a methodology that automatically designs an ANN using <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> algorithms such as Basic <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO), Second Generation of <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (SGPSO), and a New Model of PSO called NMPSO. The aim of these algorithms is to evolve, at the same time, the three principal components of an ANN: the set of synaptic weights, the connections or architecture, and the transfer functions for each neuron. Eight different fitness functions were proposed to evaluate the fitness of each solution and find the best design. These functions are based on the mean square error (MSE) and the classification error (CER) and implement a strategy to avoid overtraining and to reduce the number of connections in the ANN. In addition, the ANN designed with the proposed methodology is compared with those designed manually using the well-known Back-Propagation and Levenberg-Marquardt Learning Algorithms. Finally, the accuracy of the method is tested with different nonlinear pattern classification problems. PMID:26221132</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16551127','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16551127"><span id="translatedtitle">Considerations in identifying <span class="hlt">optimal</span> <span class="hlt">particles</span> for radiation medicine.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Slater, James M</p> <p>2006-04-01</p> <p>Of the many ionizing <span class="hlt">particles</span> discovered so far, only a few are reasonable to consider for radiation therapy. These include photons, protons, neutrons, electrons, mesons, antiprotons, and ions heavier than hydrogen. Most of these <span class="hlt">particles</span> are used therapeutically to destroy or inactivate malignant and sometimes benign cells. Since the late 1930s, accelerators have been developed that have expanded radiation oncologists' abilities to produce various ionizing <span class="hlt">particle</span> beams. Over the past decade, radiation oncologists have become increasingly interested in pursuing <span class="hlt">particles</span> other than the conventional photons that have been used almost exclusively since X-rays were discovered in 1895. Physicians recognize that normal-tissue morbidity from all forms of anti-cancer treatment is the primary factor limiting the success of those treatments. In radiation therapy, all <span class="hlt">particles</span> mentioned above can destroy any cancer cell; controlling the beam in three dimensions, thus providing the physician with the capability of avoiding normal-tissue injury, is the fundamental deficiency in the use of X-rays (photons). Heavy charged <span class="hlt">particles</span> possess near-ideal characteristics for exercising control in three dimensions; their primary differences are due to the number of protons contained within their nuclei. As their number of protons increase (atomic number) their ionization density (LET) increases. In selecting the <span class="hlt">optimal</span> <span class="hlt">particle</span> for therapy from among the heavy charged <span class="hlt">particles</span>, one must carefully consider the ionization density created by each specific <span class="hlt">particle</span>. Ionization density creates both advantages and disadvantages for patient treatment; these factors must be matched with the patients' precise clinical needs. The current state of the art involves studying the clinical advantages and disadvantages of the lightest ion, the proton, as compared to other <span class="hlt">particles</span> used or contemplated for use. Full analysis must await adequate data developed from long-term studies to determine the precise role of each potential <span class="hlt">particle</span> for human use. It is expected that one <span class="hlt">particle</span> beam will emerge as the mainstream for treating human disease, and a small number of <span class="hlt">particles</span> may emerge in an adjunctive role. PMID:16551127</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4475762','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4475762"><span id="translatedtitle">Nanodosimetry-Based Plan <span class="hlt">Optimization</span> for <span class="hlt">Particle</span> Therapy</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Casiraghi, Margherita; Schulte, Reinhard W.</p> <p>2015-01-01</p> <p>Treatment planning for <span class="hlt">particle</span> therapy is currently an active field of research due uncertainty in how to modify physical dose in order to create a uniform biological dose response in the target. A novel treatment plan <span class="hlt">optimization</span> strategy based on measurable nanodosimetric quantities rather than biophysical models is proposed in this work. Simplified proton and carbon treatment plans were simulated in a water phantom to investigate the <span class="hlt">optimization</span> feasibility. Track structures of the mixed radiation field produced at different depths in the target volume were simulated with Geant4-DNA and nanodosimetric descriptors were calculated. The fluences of the treatment field pencil beams were <span class="hlt">optimized</span> in order to create a mixed field with equal nanodosimetric descriptors at each of the multiple positions in spread-out <span class="hlt">particle</span> Bragg peaks. For both proton and carbon ion plans, a uniform spatial distribution of nanodosimetric descriptors could be obtained by <span class="hlt">optimizing</span> opposing-field but not single-field plans. The results obtained indicate that uniform nanodosimetrically weighted plans, which may also be radiobiologically uniform, can be obtained with this approach. Future investigations need to demonstrate that this approach is also feasible for more complicated beam arrangements and that it leads to biologically uniform response in tumor cells and tissues. PMID:26167202</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SPIE.7497E..0LX','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SPIE.7497E..0LX"><span id="translatedtitle"><span class="hlt">Optimal</span> control of switched linear systems based on Migrant <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> algorithm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xie, Fuqiang; Wang, Yongji; Zheng, Zongzhun; Li, Chuanfeng</p> <p>2009-10-01</p> <p>The <span class="hlt">optimal</span> control problem for switched linear systems with internally forced switching has more constraints than with externally forced switching. Heavy computations and slow convergence in solving this problem is a major obstacle. In this paper we describe a new approach for solving this problem, which is called Migrant <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (Migrant PSO). Imitating the behavior of a flock of migrant birds, the Migrant PSO applies naturally to both continuous and discrete spaces, in which definitive <span class="hlt">optimization</span> algorithm and stochastic search method are combined. The efficacy of the proposed algorithm is illustrated via a numerical example.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.A23K..05K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.A23K..05K"><span id="translatedtitle">Effects of <span class="hlt">Particle</span> <span class="hlt">Filters</span> and Accelerated Engine Replacement on Heavy-Duty Diesel Vehicle Emissions of Black Carbon, Nitrogen Oxides, and Ultrafine <span class="hlt">Particles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kirchstetter, T.; Preble, C.; Dallmann, T. R.; DeMartini, S. J.; Tang, N. W.; Kreisberg, N. M.; Hering, S. V.; Harley, R. A.</p> <p>2013-12-01</p> <p>Diesel <span class="hlt">particle</span> <span class="hlt">filters</span> have become widely used in the United States since the introduction in 2007 of a more stringent exhaust particulate matter emission standard for new heavy-duty diesel vehicle engines. California has instituted additional regulations requiring retrofit or replacement of older in-use engines to accelerate emission reductions and air quality improvements. This presentation summarizes pollutant emission changes measured over several field campaigns at the Port of Oakland in the San Francisco Bay Area associated with diesel particulate <span class="hlt">filter</span> use and accelerated modernization of the heavy-duty truck fleet. Pollutants in the exhaust plumes of hundreds of heavy-duty trucks en route to the Port were measured in 2009, 2010, 2011, and 2013. Ultrafine <span class="hlt">particle</span> number, black carbon (BC), nitrogen oxides (NOx), and nitrogen dioxide (NO2) concentrations were measured at a frequency ≤ 1 Hz and normalized to measured carbon dioxide concentrations to quantify fuel-based emission factors (grams of pollutant emitted per kilogram of diesel consumed). The size distribution of <span class="hlt">particles</span> in truck exhaust plumes was also measured at 1 Hz. In the two most recent campaigns, emissions were linked on a truck-by-truck basis to installed emission control equipment via the matching of transcribed license plates to a Port truck database. Accelerated replacement of older engines with newer engines and retrofit of trucks with diesel <span class="hlt">particle</span> <span class="hlt">filters</span> reduced fleet-average emissions of BC and NOx. Preliminary results from the two most recent field campaigns indicate that trucks without diesel <span class="hlt">particle</span> <span class="hlt">filters</span> emit 4 times more BC than <span class="hlt">filter</span>-equipped trucks. Diesel <span class="hlt">particle</span> <span class="hlt">filters</span> increase emissions of NO2, however, and <span class="hlt">filter</span>-equipped trucks have NO2/NOx ratios that are 4 to 7 times greater than trucks without <span class="hlt">filters</span>. Preliminary findings related to <span class="hlt">particle</span> size distribution indicate that (a) most trucks emitted <span class="hlt">particles</span> characterized by a single mode of approximately 100 nm in diameter and (b) new trucks originally equipped with diesel <span class="hlt">particle</span> <span class="hlt">filters</span> were 5 to 6 times more likely than <span class="hlt">filter</span>-retrofitted trucks and trucks without <span class="hlt">filters</span> to emit <span class="hlt">particles</span> characterized by a single mode in the range of 10 to 30 nm in diameter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24273145','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24273145"><span id="translatedtitle"><span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> for discrete-time inverse <span class="hlt">optimal</span> control of a doubly fed induction generator.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ruiz-Cruz, Riemann; Sanchez, Edgar N; Ornelas-Tellez, Fernando; Loukianov, Alexander G; Harley, Ronald G</p> <p>2013-12-01</p> <p>In this paper, the authors propose a <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO) for a discrete-time inverse <span class="hlt">optimal</span> control scheme of a doubly fed induction generator (DFIG). For the inverse <span class="hlt">optimal</span> scheme, a control Lyapunov function (CLF) is proposed to obtain an inverse <span class="hlt">optimal</span> control law in order to achieve trajectory tracking. A posteriori, it is established that this control law minimizes a meaningful cost function. The CLFs depend on matrix selection in order to achieve the control objectives; this matrix is determined by two mechanisms: initially, fixed parameters are proposed for this matrix by a trial-and-error method and then by using the PSO algorithm. The inverse <span class="hlt">optimal</span> control scheme is illustrated via simulations for the DFIG, including the comparison between both mechanisms. PMID:24273145</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120017458','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120017458"><span id="translatedtitle">Representation of Probability Density Functions from Orbit Determination using the <span class="hlt">Particle</span> <span class="hlt">Filter</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mashiku, Alinda K.; Garrison, James; Carpenter, J. Russell</p> <p>2012-01-01</p> <p>Statistical orbit determination enables us to obtain estimates of the state and the statistical information of its region of uncertainty. In order to obtain an accurate representation of the probability density function (PDF) that incorporates higher order statistical information, we propose the use of nonlinear estimation methods such as the <span class="hlt">Particle</span> <span class="hlt">Filter</span>. The <span class="hlt">Particle</span> <span class="hlt">Filter</span> (PF) is capable of providing a PDF representation of the state estimates whose accuracy is dependent on the number of <span class="hlt">particles</span> or samples used. For this method to be applicable to real case scenarios, we need a way of accurately representing the PDF in a compressed manner with little information loss. Hence we propose using the Independent Component Analysis (ICA) as a non-Gaussian dimensional reduction method that is capable of maintaining higher order statistical information obtained using the PF. Methods such as the Principal Component Analysis (PCA) are based on utilizing up to second order statistics, hence will not suffice in maintaining maximum information content. Both the PCA and the ICA are applied to two scenarios that involve a highly eccentric orbit with a lower apriori uncertainty covariance and a less eccentric orbit with a higher a priori uncertainty covariance, to illustrate the capability of the ICA in relation to the PCA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26501280','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26501280"><span id="translatedtitle">Modified <span class="hlt">particle</span> <span class="hlt">filtering</span> algorithm for single acoustic vector sensor DOA tracking.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Xinbo; Sun, Haixin; Jiang, Liangxu; Shi, Yaowu; Wu, Yue</p> <p>2015-01-01</p> <p>The conventional direction of arrival (DOA) estimation algorithm with static sources assumption usually estimates the source angles of two adjacent moments independently and the correlation of the moments is not considered. In this article, we focus on the DOA estimation of moving sources and a modified <span class="hlt">particle</span> <span class="hlt">filtering</span> (MPF) algorithm is proposed with state space model of single acoustic vector sensor. Although the <span class="hlt">particle</span> <span class="hlt">filtering</span> (PF) algorithm has been introduced for acoustic vector sensor applications, it is not suitable for the case that one dimension angle of source is estimated with large deviation, the two dimension angles (pitch angle and azimuth angle) cannot be simultaneously employed to update the state through resampling processing of PF algorithm. To solve the problems mentioned above, the MPF algorithm is proposed in which the state estimation of previous moment is introduced to the <span class="hlt">particle</span> sampling of present moment to improve the importance function. Moreover, the independent relationship of pitch angle and azimuth angle is considered and the two dimension angles are sampled and evaluated, respectively. Then, the MUSIC spectrum function is used as the "likehood" function of the MPF algorithm, and the modified PF-MUSIC (MPF-MUSIC) algorithm is proposed to improve the root mean square error (RMSE) and the probability of convergence. The theoretical analysis and the simulation results validate the effectiveness and feasibility of the two proposed algorithms. PMID:26501280</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4634417','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4634417"><span id="translatedtitle">Modified <span class="hlt">Particle</span> <span class="hlt">Filtering</span> Algorithm for Single Acoustic Vector Sensor DOA Tracking</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Li, Xinbo; Sun, Haixin; Jiang, Liangxu; Shi, Yaowu; Wu, Yue</p> <p>2015-01-01</p> <p>The conventional direction of arrival (DOA) estimation algorithm with static sources assumption usually estimates the source angles of two adjacent moments independently and the correlation of the moments is not considered. In this article, we focus on the DOA estimation of moving sources and a modified <span class="hlt">particle</span> <span class="hlt">filtering</span> (MPF) algorithm is proposed with state space model of single acoustic vector sensor. Although the <span class="hlt">particle</span> <span class="hlt">filtering</span> (PF) algorithm has been introduced for acoustic vector sensor applications, it is not suitable for the case that one dimension angle of source is estimated with large deviation, the two dimension angles (pitch angle and azimuth angle) cannot be simultaneously employed to update the state through resampling processing of PF algorithm. To solve the problems mentioned above, the MPF algorithm is proposed in which the state estimation of previous moment is introduced to the <span class="hlt">particle</span> sampling of present moment to improve the importance function. Moreover, the independent relationship of pitch angle and azimuth angle is considered and the two dimension angles are sampled and evaluated, respectively. Then, the MUSIC spectrum function is used as the “likehood” function of the MPF algorithm, and the modified PF-MUSIC (MPF-MUSIC) algorithm is proposed to improve the root mean square error (RMSE) and the probability of convergence. The theoretical analysis and the simulation results validate the effectiveness and feasibility of the two proposed algorithms. PMID:26501280</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AcAau..94..852P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AcAau..94..852P"><span id="translatedtitle"><span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> of ascent trajectories of multistage launch vehicles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pontani, Mauro</p> <p>2014-02-01</p> <p>Multistage launch vehicles are commonly employed to place spacecraft and satellites in their operational orbits. If the rocket characteristics are specified, the <span class="hlt">optimization</span> of its ascending trajectory consists of determining the <span class="hlt">optimal</span> control law that leads to maximizing the final mass at orbit injection. The numerical solution of a similar problem is not trivial and has been pursued with different methods, for decades. This paper is concerned with an original approach based on the joint use of swarming theory and the necessary conditions for <span class="hlt">optimality</span>. The <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> technique represents a heuristic population-based <span class="hlt">optimization</span> method inspired by the natural motion of bird flocks. Each individual (or <span class="hlt">particle</span>) that composes the swarm corresponds to a solution of the problem and is associated with a position and a velocity vector. The formula for velocity updating is the core of the method and is composed of three terms with stochastic weights. As a result, the population migrates toward different regions of the search space taking advantage of the mechanism of information sharing that affects the overall swarm dynamics. At the end of the process the best <span class="hlt">particle</span> is selected and corresponds to the <span class="hlt">optimal</span> solution to the problem of interest. In this work the three-dimensional trajectory of the multistage rocket is assumed to be composed of four arcs: (i) first stage propulsion, (ii) second stage propulsion, (iii) coast arc (after release of the second stage), and (iv) third stage propulsion. The Euler-Lagrange equations and the Pontryagin minimum principle, in conjunction with the Weierstrass-Erdmann corner conditions, are employed to express the thrust angles as functions of the adjoint variables conjugate to the dynamics equations. The use of these analytical conditions coming from the calculus of variations leads to obtaining the overall rocket dynamics as a function of seven parameters only, namely the unknown values of the initial state and costate components, the coast duration, and the upper stage thrust duration. In addition, a simple approach is introduced and successfully applied with the purpose of satisfying exactly the path constraint related to the maximum dynamical pressure in the atmospheric phase. The basic version of the swarming technique, which is used in this research, is extremely simple and easy to program. Nevertheless, the algorithm proves to be capable of yielding the <span class="hlt">optimal</span> rocket trajectory with a very satisfactory numerical accuracy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007SPIE.6764E..0UC','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007SPIE.6764E..0UC"><span id="translatedtitle">Dynamic omni-directional vision localization using a beacon tracker based on <span class="hlt">particle</span> <span class="hlt">filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cao, Zuoliang; Liu, Shiyu</p> <p>2007-09-01</p> <p>Omni-directional vision navigation for AGVs appears definite significant since its advantage of panoramic sight with a single compact visual scene. This unique guidance technique involves target recognition, vision tracking, object positioning, path programming. An algorithm for omni-vision based global localization which utilizes two overhead features as beacon pattern is proposed in this paper. An approach for geometric restoration of omni-vision images has to be considered since an inherent distortion exists. The mapping between image coordinates and physical space parameters of the targets can be obtained by means of the imaging principle on the fisheye lens. The localization of the robot can be achieved by geometric computation. Dynamic localization employs a beacon tracker to follow the landmarks in real time during the arbitrary movement of the vehicle. The coordinate transformation is devised for path programming based on time sequence images analysis. The beacon recognition and tracking are a key procedure for an omni-vision guided mobile unit. The conventional image processing such as shape decomposition, description, matching and other usually employed technique are not directly applicable in omni-vision. <span class="hlt">Particle</span> <span class="hlt">filter</span> (PF) has been shown to be successful for several nonlinear estimation problems. A beacon tracker based on <span class="hlt">Particle</span> <span class="hlt">Filter</span> which offers a probabilistic framework for dynamic state estimation in visual tracking has been developed. We independently use two <span class="hlt">Particle</span> <span class="hlt">Filters</span> to track double landmarks but a composite algorithm on multiple objects tracking conducts for vehicle localization. We have implemented the tracking and localization system and demonstrated the relevant of the algorithm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9808E..3QL','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9808E..3QL"><span id="translatedtitle">Spatial join <span class="hlt">optimization</span> among WFSs based on recursive partitioning and <span class="hlt">filtering</span> rate estimation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lan, Guiwen; Wu, Congcong; Shi, Guangyi; Chen, Qi; Yang, Zhao</p> <p>2015-12-01</p> <p>Spatial join among Web Feature Services (WFS) is time-consuming for most of non-candidate spatial objects may be encoded by GML and transferred to client side. In this paper, an <span class="hlt">optimization</span> strategy is proposed to enhance performance of these joins by <span class="hlt">filtering</span> non-candidate spatial objects as many as possible. By recursive partitioning, the data skew of sub-areas is facilitated to reduce data transmission using spatial semi-join. Moreover <span class="hlt">filtering</span> rate is used to determine whether a spatial semi-join for a sub-area is profitable and choose a suitable execution plan for it. The experimental results show that the proposed strategy is feasible under most circumstances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26736755','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26736755"><span id="translatedtitle">Spatial <span class="hlt">filter</span> and feature selection <span class="hlt">optimization</span> based on EA for multi-channel EEG.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yubo Wang; Mohanarangam, Krithikaa; Mallipeddi, Rammohan; Veluvolu, K C</p> <p>2015-08-01</p> <p>The EEG signals employed for BCI systems are generally band-limited. The band-limited multiple Fourier linear combiner (BMFLC) with Kalman <span class="hlt">filter</span> was developed to obtain amplitude estimates of the EEG signal in a pre-fixed frequency band in real-time. However, the high-dimensionality of the feature vector caused by the application of BMFLC to multi-channel EEG based BCI deteriorates the performance of the classifier. In this work, we apply evolutionary algorithm (EA) to tackle this problem. The real-valued EA encodes both the spatial <span class="hlt">filter</span> and the feature selection into its solution and <span class="hlt">optimizes</span> it with respect to the classification error. Three BMFLC based BCI configurations are proposed. Our results show that the BMFLC-KF with covariance matrix adaptation evolution strategy (CMAES) has the best overall performance. PMID:26736755</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011SCPMA..54.1083Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011SCPMA..54.1083Z"><span id="translatedtitle">An algorithm for terrain-aided inertial navigation based on nonlinear <span class="hlt">optimal</span> <span class="hlt">filtering</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Long</p> <p>2011-06-01</p> <p>When the initial position error or the altimeter measurement noise is large, the BUAA Inertial Terrain-Aided Navigation (BITAN) algorithm based on extended Kalman <span class="hlt">filtering</span> can not be located accurately. To solve this problem, we propose a modified BITAN algorithm based on nonlinear <span class="hlt">optimal</span> <span class="hlt">filtering</span>. The posterior probability density correction is obtained by using the prior probability density of the system's state transition model and the most recent observations. Hence, the local unobservable system caused by the measurement equation through terrain linearization is avoided. This algorithm is tested by using the digital elevation model and flight data, and is compared with BITAN. Results show that the accuracy of the proposed algorithm is higher than BITAN, and the robustness of the system is improved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003SPIE.5100...73T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003SPIE.5100...73T"><span id="translatedtitle"><span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> for the clustering of wireless sensors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tillett, Jason C.; Rao, Raghuveer M.; Sahin, Ferat; Rao, T. M.</p> <p>2003-07-01</p> <p>Clustering is necessary for data aggregation, hierarchical routing, <span class="hlt">optimizing</span> sleep patterns, election of extremal sensors, <span class="hlt">optimizing</span> coverage and resource allocation, reuse of frequency bands and codes, and conserving energy. <span class="hlt">Optimal</span> clustering is typically an NP-hard problem. Solutions to NP-hard problems involve searches through vast spaces of possible solutions. Evolutionary algorithms have been applied successfully to a variety of NP-hard problems. We explore one such approach, <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO), an evolutionary programming technique where a 'swarm' of test solutions, analogous to a natural swarm of bees, ants or termites, is allowed to interact and cooperate to find the best solution to the given problem. We use the PSO approach to cluster sensors in a sensor network. The energy efficiency of our clustering in a data-aggregation type sensor network deployment is tested using a modified LEACH-C code. The PSO technique with a recursive bisection algorithm is tested against random search and simulated annealing; the PSO technique is shown to be robust. We further investigate developing a distributed version of the PSO algorithm for clustering <span class="hlt">optimally</span> a wireless sensor network.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AIPC.1298....7R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AIPC.1298....7R"><span id="translatedtitle"><span class="hlt">Particle</span> Swarm and Ant Colony Approaches in Multiobjective <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rao, S. S.</p> <p>2010-10-01</p> <p>The social behavior of groups of birds, ants, insects and fish has been used to develop evolutionary algorithms known as swarm intelligence techniques for solving <span class="hlt">optimization</span> problems. This work presents the development of strategies for the application of two of the popular swarm intelligence techniques, namely the <span class="hlt">particle</span> swarm and ant colony methods, for the solution of multiobjective <span class="hlt">optimization</span> problems. In a multiobjective <span class="hlt">optimization</span> problem, the objectives exhibit a conflicting nature and hence no design vector can minimize all the objectives simultaneously. The concept of Pareto-<span class="hlt">optimal</span> solution is used in finding a compromise solution. A modified cooperative game theory approach, in which each objective is associated with a different player, is used in this work. The applicability and computational efficiencies of the proposed techniques are demonstrated through several illustrative examples involving unconstrained and constrained problems with single and multiple objectives and continuous and mixed design variables. The present methodologies are expected to be useful for the solution of a variety of practical continuous and mixed <span class="hlt">optimization</span> problems involving single or multiple objectives with or without constraints.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JSDD....1..410S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JSDD....1..410S"><span id="translatedtitle">Augmented Lagrangian <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> in Mechanism Design</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sedlaczek, Kai; Eberhard, Peter</p> <p></p> <p>The problem of <span class="hlt">optimizing</span> nonlinear multibody systems is in general nonlinear and nonconvex. This is especially true for the dimensional synthesis process of rigid body mechanisms, where often only local solutions might be found with gradient-based <span class="hlt">optimization</span> methods. An attractive alternative for solving such multimodal <span class="hlt">optimization</span> problems is the <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) algorithm. This stochastic solution technique allows a derivative-free search for a global solution without the need for any initial design. In this work, we present an extension to the basic PSO algorithm in order to solve the problem of dimensional synthesis with nonlinear equality and inequality constraints. It utilizes the Augmented Lagrange Multiplier Method in combination with an advanced non-stationary penalty function approach that does not rely on excessively large penalty factors for sufficiently accurate solutions. Although the PSO method is even able to solve nonsmooth and discrete problems, this augmented algorithm can additionally calculate accurate Lagrange multiplier estimates for differentiable formulations, which are helpful in the analysis process of the <span class="hlt">optimization</span> results. We demonstrate this method and show its very promising applicability to the constrained dimensional synthesis process of rigid body mechanisms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ITEIS.131.2196N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ITEIS.131.2196N"><span id="translatedtitle">Tracking and Feature Extraction of Easily Deformable Object Using <span class="hlt">Particle</span> <span class="hlt">Filter</span> and Adaptive Vector Quantization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nishida, Takeshi; Ikoma, Norikazu; Kurogi, Shuichi; Sakamoto, Tetsuzo</p> <p></p> <p>PF-mCRL method is a rapid and robust information extraction method for non-Gaussian probability distribution by combination of a <span class="hlt">particle</span> <span class="hlt">filter</span> (PF) and an adaptive vector quantization algorithm mCRL (modified Competitive Re-initialization Learning). In this research, a novel method for tracking and shape estimation of easily deformable object in dynamic scene by using the PF-mCRL is proposed. Moreover, several feature value extraction methods from output of PF-mCRL useful for the robot handling are proposed. Further, effectiveness of this proposed method is shown by a real image experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18002445','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18002445"><span id="translatedtitle">Indoor patient position estimation using <span class="hlt">particle</span> <span class="hlt">filtering</span> and wireless body area networks.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ren, Hongliang; Meng, Max Q H; Xu, Lisheng</p> <p>2007-01-01</p> <p>Wireless Body Area Network (WBAN) has been recently promoted to monitor the physiological parameters of patient in an unobtrusive and natural way. This paper towards to make advantage of those ongoing wireless communication links between the body sensors to provide estimated position information of patients or particular body area networks, which make daily activity surveillance possible for further analysis. The proposed <span class="hlt">particle</span> <span class="hlt">filtering</span> based localization algorithm just picks up the received radio signal strength information from beacons or its neighbors to infer its own pose, which do not require additional hardware or instruments. Theoretical analysis and simulation experiments are presented to examine the performance of location estimating method. PMID:18002445</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26987381','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26987381"><span id="translatedtitle">Characterization of exhaled breath <span class="hlt">particles</span> collected by an electret <span class="hlt">filter</span> technique.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tinglev, Åsa Danielsson; Ullah, Shahid; Ljungkvist, Göran; Viklund, Emilia; Olin, Anna-Carin; Beck, Olof</p> <p>2016-01-01</p> <p>Aerosol <span class="hlt">particles</span> that are present in exhaled breath carry nonvolatile components and have gained interest as a specimen for potential biomarkers. Nonvolatile compounds detected in exhaled breath include both endogenous and exogenous compounds. The aim of this study was to study <span class="hlt">particles</span> collected with a new, simple and convenient <span class="hlt">filter</span> technique. Samples of breath were collected from healthy volunteers from approximately 30 l of exhaled air. <span class="hlt">Particles</span> were counted with an optical <span class="hlt">particle</span> counter and two phosphatidylcholines were measured by liquid chromatography-tandem mass spectrometry. In addition, phosphatidylcholines and methadone was analysed in breath from patients in treatment with methadone and oral fluid was collected with the Quantisal device. The results demonstrated that the majority of <span class="hlt">particles</span> are  <1 μm in size and that the fraction of larger <span class="hlt">particle</span> contributes most to the total mass. The phosphatidylcholine PC(16 : 0/16 : 0) dominated over PC(16 : 0/18 : 1) and represented a major constituent of the <span class="hlt">particles</span>. The concentration of the PC(16 : 0/16 : 0) homolog was significantly correlated (p  <  0.001) with total mass. From the low concentration of the two phosphatidylcholines and their relative abundance in oral fluid a major contribution from the oral cavity could be ruled out. The concentration of PC(16 : 0/16 : 0) in breath was positively correlated with age (p  <  0.01). An attempt to use PC(16 : 0/16 : 0) as a sample size indicator for methadone was not successful, as the large intra-individual variability between samplings even increased after normalization. In conclusion, it was demonstrated that exhaled breath sampled with the <span class="hlt">filter</span> device represents a specimen corresponding to surfactant. The possible use of PC(16 : 0/16 : 0) as a sample size indicator was supported and deserves further investigations. We propose that the direct and selective collection of the breath aerosol <span class="hlt">particles</span> is a promising strategy for measurement of nonvolatiles in breath. PMID:26987381</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.A21F0110K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.A21F0110K"><span id="translatedtitle"><span class="hlt">Optimal</span> Shape in Electromagnetic Scattering by Small Aspherical <span class="hlt">Particles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kostinski, A. B.; Mongkolsittisilp, A.</p> <p>2013-12-01</p> <p>We consider the question of <span class="hlt">optimal</span> shape for scattering by randomly oriented <span class="hlt">particles</span>, e.g., shape causing minimal extinction among those of equal volume. Guided by the isoperimetric property of a sphere, relevant in the geometrical optics limit of scattering by large <span class="hlt">particles</span>, we examine an analogous question in the low frequency (electrostatics) approximation, seeking to disentangle electric and geometric contributions. To that end, we survey the literature on shape functionals and focus on ellipsoids, giving a simple proof of spherical <span class="hlt">optimality</span> for the coated ellipsoidal <span class="hlt">particle</span>. Monotonic increase with asphericity in the low frequency regime for orientation-averaged induced dipole moments and scattering cross-sections is also established. Additional physical insight is obtained from the Rayleigh-Gans (transparent) limit and eccentricity expansions. We propose linking low and high frequency regime in a single minimum principle valid for all size parameters, provided that reasonable size distributions wash out the resonances for inter-mediate size parameters. This proposal is further supported by the sum rule for integrated extinction. Implications for spectro-polarimetric scattering are explicitly considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050182658','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050182658"><span id="translatedtitle">A Parallel <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> Algorithm Accelerated by Asynchronous Evaluations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Venter, Gerhard; Sobieszczanski-Sobieski, Jaroslaw</p> <p>2005-01-01</p> <p>A parallel <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) algorithm is presented. <span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> is a fairly recent addition to the family of non-gradient based, probabilistic search algorithms that is based on a simplified social model and is closely tied to swarming theory. Although PSO algorithms present several attractive properties to the designer, they are plagued by high computational cost as measured by elapsed time. One approach to reduce the elapsed time is to make use of coarse-grained parallelization to evaluate the design points. Previous parallel PSO algorithms were mostly implemented in a synchronous manner, where all design points within a design iteration are evaluated before the next iteration is started. This approach leads to poor parallel speedup in cases where a heterogeneous parallel environment is used and/or where the analysis time depends on the design point being analyzed. This paper introduces an asynchronous parallel PSO algorithm that greatly improves the parallel e ciency. The asynchronous algorithm is benchmarked on a cluster assembled of Apple Macintosh G5 desktop computers, using the multi-disciplinary <span class="hlt">optimization</span> of a typical transport aircraft wing as an example.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24072983','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24072983"><span id="translatedtitle">Discrete <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> with scout <span class="hlt">particles</span> for library materials acquisition.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wu, Yi-Ling; Ho, Tsu-Feng; Shyu, Shyong Jian; Lin, Bertrand M T</p> <p>2013-01-01</p> <p>Materials acquisition is one of the critical challenges faced by academic libraries. This paper presents an integer programming model of the studied problem by considering how to select materials in order to maximize the average preference and the budget execution rate under some practical restrictions including departmental budget, limitation of the number of materials in each category and each language. To tackle the constrained problem, we propose a discrete <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (DPSO) with scout <span class="hlt">particles</span>, where each <span class="hlt">particle</span>, represented as a binary matrix, corresponds to a candidate solution to the problem. An initialization algorithm and a penalty function are designed to cope with the constraints, and the scout <span class="hlt">particles</span> are employed to enhance the exploration within the solution space. To demonstrate the effectiveness and efficiency of the proposed DPSO, a series of computational experiments are designed and conducted. The results are statistically analyzed, and it is evinced that the proposed DPSO is an effective approach for the studied problem. PMID:24072983</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SPIE.7495E..14C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SPIE.7495E..14C"><span id="translatedtitle">Fusion of cues for occlusion handling in tracking with <span class="hlt">particle</span> <span class="hlt">filters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Xiaobo; Men, Aidong; Pan, Xinting; Yang, Bo; Wang, Wei</p> <p>2009-10-01</p> <p>In this paper, a new approach is presented for tracking object accurately and steadily when the target encountering occlusion in video sequences. First, we use Canny algorithm to extract the edges of the object. The edge pixels are classified as foreground/background for each frame using background subtraction. On the next stage, a set of cues including a motion model, an elliptical shape model, a spatial-color mixture of Gaussians appearance model, and an edge orientation histogram model is fused in a principled manner. All these cues could be modeled by a data likelihood function; Then, a <span class="hlt">particle</span> <span class="hlt">filter</span> algorithm is used for tracking and the <span class="hlt">particles</span> are re-sampled based on the fusion of the cues. Result form simulations and experiments with real video sequences show the effectiveness of our approach for tracking people under occlusion conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SPIE.7383E..1CW','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SPIE.7383E..1CW"><span id="translatedtitle">Study on color image tracking and detection algorithms based on <span class="hlt">particle</span> <span class="hlt">filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Chuan; Sun, Hai-jiang; Yang, Dong</p> <p>2009-07-01</p> <p>In Video tracking, detection and tracking need two algorithms. The process is complex and need much time which detection and tracking is. In this paper a hybrid valued sequential state vector is formulated. The state vector is characterized by information of target appearance and of location. <span class="hlt">Particle</span> <span class="hlt">filter</span>-based method implements detection and tracking. In order to reduce process time and think of pixel position in tracking field, feature histogram of color-based is as observe vector and used posterior estimate. The experimental results confirm that method can detect and track object in 17.68ms successfully when the number of <span class="hlt">particles</span> is 160. The method is robust for rolling ,scale and partial occlusion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008ITEIS.128.1447K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008ITEIS.128.1447K"><span id="translatedtitle">3D Head Pose Tracking Using a <span class="hlt">Particle</span> <span class="hlt">Filter</span> with Nose Template Matching</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kubota, Hitoshi; Takeshi, Masami; Saito, Hideo</p> <p></p> <p>In this paper, we propose a real-time tracking method for driver's head pose in real vehicle environment by using multiple NIR cameras. In order to achieve real-time performance and high-accuracy, 6-DOF of head pose is estimated by a <span class="hlt">particle</span> <span class="hlt">filter</span> with restricted state space. Firstly, the 3D position of nose hole is measured by template matching of stereo images. Because nose hole is the most dark area in the captured NIR images, we can robustly detect the position of the nose very precisely. From the 3D position of the nose, we can estimate the head pose as an initial estimate. Then, each hypothesis is updated by prior probability with a constraint of nose position. Thus it can reduce the number of <span class="hlt">particles</span> with maintained accuracy. The experimental results indicate that this method is effective for head pose tracking.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22915477','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22915477"><span id="translatedtitle"><span class="hlt">Particle</span> image velocimetry (PIV) study of rotating cylindrical <span class="hlt">filters</span> for animal cell perfusion processes.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Figueredo-Cardero, Alvio; Chico, Ernesto; Castilho, Leda; de Andrade Medronho, Ricardo</p> <p>2012-01-01</p> <p>In the present work, the main fluid flow features inside a rotating cylindrical filtration (RCF) system used as external cell retention device for animal cell perfusion processes were investigated using <span class="hlt">particle</span> image velocimetry (PIV). The motivation behind this work was to provide experimental fluid dynamic data for such turbulent flow using a high-permeability <span class="hlt">filter</span>, given the lack of information about this system in the literature. The results shown herein gave evidence that, at the boundary between the <span class="hlt">filter</span> mesh and the fluid, a slip velocity condition in the tangential direction does exist, which had not been reported in the literature so far. In the RCF system tested, this accounted for a fluid velocity 10% lower than that of the <span class="hlt">filter</span> tip, which could be important for the cake formation kinetics during filtration. Evidence confirming the existence of Taylor vortices under conditions of turbulent flow and high permeability, typical of animal cell perfusion RCF systems, was obtained. Second-order turbulence statistics were successfully calculated. The radial behavior of the second-order turbulent moments revealed that turbulence in this system is highly anisotropic, which is relevant for performing numerical simulations of this system. PMID:22915477</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000PhRvD..61j2001B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000PhRvD..61j2001B"><span id="translatedtitle">?2 testing of <span class="hlt">optimal</span> <span class="hlt">filters</span> for gravitational wave signals: An experimental implementation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baggio, L.; Cerdonio, M.; Ortolan, A.; Vedovato, G.; Taffarello, L.; Zendri, J.-P.; Bonaldi, M.; Falferi, P.; Martinucci, V.; Mezzena, R.; Prodi, G. A.; Vitale, S.</p> <p>2000-05-01</p> <p>We have implemented likelihood testing of the performance of an <span class="hlt">optimal</span> <span class="hlt">filter</span> within the online analysis of AURIGA, a sub-Kelvin resonant-bar gravitational wave detector. We demonstrate the effectiveness of this technique in discriminating between impulsive mechanical excitations of the resonant-bar and other spurious excitations. This technique also ensures the accuracy of the estimated parameters such as the signal-to-noise ratio. The efficiency of the technique to deal with nonstationary noise and its application to data from a network of detectors are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26176879','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26176879"><span id="translatedtitle">Biofuel-Promoted Polychlorinated Dibenzodioxin/furan Formation in an Iron-Catalyzed Diesel <span class="hlt">Particle</span> <span class="hlt">Filter</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Heeb, Norbert V; Rey, Maria Dolores; Zennegg, Markus; Haag, Regula; Wichser, Adrian; Schmid, Peter; Seiler, Cornelia; Honegger, Peter; Zeyer, Kerstin; Mohn, Joachim; Bürki, Samuel; Zimmerli, Yan; Czerwinski, Jan; Mayer, Andreas</p> <p>2015-08-01</p> <p>Iron-catalyzed diesel <span class="hlt">particle</span> <span class="hlt">filters</span> (DPFs) are widely used for <span class="hlt">particle</span> abatement. Active catalyst <span class="hlt">particles</span>, so-called fuel-borne catalysts (FBCs), are formed in situ, in the engine, when combusting precursors, which were premixed with the fuel. The obtained iron oxide <span class="hlt">particles</span> catalyze soot oxidation in <span class="hlt">filters</span>. Iron-catalyzed DPFs are considered as safe with respect to their potential to form polychlorinated dibenzodioxins/furans (PCDD/Fs). We reported that a bimetallic potassium/iron FBC supported an intense PCDD/F formation in a DPF. Here, we discuss the impact of fatty acid methyl ester (FAME) biofuel on PCDD/F emissions. The iron-catalyzed DPF indeed supported a PCDD/F formation with biofuel but remained inactive with petroleum-derived diesel fuel. PCDD/F emissions (I-TEQ) increased 23-fold when comparing biofuel and diesel data. Emissions of 2,3,7,8-TCDD, the most toxic congener [toxicity equivalence factor (TEF) = 1.0], increased 90-fold, and those of 2,3,7,8-TCDF (TEF = 0.1) increased 170-fold. Congener patterns also changed, indicating a preferential formation of tetra- and penta-chlorodibenzofurans. Thus, an inactive iron-catalyzed DPF becomes active, supporting a PCDD/F formation, when operated with biofuel containing impurities of potassium. Alkali metals are inherent constituents of biofuels. According to the current European Union (EU) legislation, levels of 5 μg/g are accepted. We conclude that risks for a secondary PCDD/F formation in iron-catalyzed DPFs increase when combusting potassium-containing biofuels. PMID:26176879</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015CoPhC.186...11S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015CoPhC.186...11S"><span id="translatedtitle">Structural <span class="hlt">optimization</span> of Pt-Pd alloy nanoparticles using an improved discrete <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> algorithm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shao, Gui-Fang; Wang, Ting-Na; Liu, Tun-Dong; Chen, Jun-Ren; Zheng, Ji-Wen; Wen, Yu-Hua</p> <p>2015-01-01</p> <p>Pt-Pd alloy nanoparticles, as potential catalyst candidates for new-energy resources such as fuel cells and lithium ion batteries owing to their excellent reactivity and selectivity, have aroused growing attention in the past years. Since structure determines physical and chemical properties of nanoparticles, the development of a reliable method for searching the stable structures of Pt-Pd alloy nanoparticles has become of increasing importance to exploring the origination of their properties. In this article, we have employed the <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> algorithm to investigate the stable structures of alloy nanoparticles with fixed shape and atomic proportion. An improved discrete <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> algorithm has been proposed and the corresponding scheme has been presented. Subsequently, the swap operator and swap sequence have been applied to reduce the probability of premature convergence to the local optima. Furthermore, the parameters of the exchange probability and the '<span class="hlt">particle</span>' size have also been considered in this article. Finally, tetrahexahedral Pt-Pd alloy nanoparticles has been used to test the effectiveness of the proposed method. The calculated results verify that the improved <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> algorithm has superior convergence and stability compared with the traditional one.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009LNCS.5854..281F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009LNCS.5854..281F"><span id="translatedtitle">Constraint Web Service Composition Based on Discrete <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fang, Xianwen; Fan, Xiaoqin; Yin, Zhixiang</p> <p></p> <p>Web service composition provides an open, standards-based approach for connecting web services together to create higher-level business processes. The Standards are designed to reduce the complexity required to compose web services, hence reducing time and costs, and increase overall efficiency in businesses. This paper present independent global constrains web service composition <span class="hlt">optimization</span> methods based on Discrete <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (DPSO) and associate Petri net (APN). Combining with the properties of APN, an efficient DPSO algorithm is presented which is used to search a legal firing sequence in the APN model. Using legal firing sequences of the Petri net makes the service composition locating space based on DPSO shrink greatly. Finally, for comparing our methods with the approximating methods, the simulation experiment is given out. Theoretical analysis and experimental results indicate that this method owns both lower computation cost and higher success ratio of service composition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Nanos...715175D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Nanos...715175D"><span id="translatedtitle">A challenge for theranostics: is the <span class="hlt">optimal</span> <span class="hlt">particle</span> for therapy also <span class="hlt">optimal</span> for diagnostics?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dreifuss, Tamar; Betzer, Oshra; Shilo, Malka; Popovtzer, Aron; Motiei, Menachem; Popovtzer, Rachela</p> <p>2015-09-01</p> <p>Theranostics is defined as the combination of therapeutic and diagnostic capabilities in the same agent. Nanotechnology is emerging as an efficient platform for theranostics, since nanoparticle-based contrast agents are powerful tools for enhancing in vivo imaging, while therapeutic nanoparticles may overcome several limitations of conventional drug delivery systems. Theranostic nanoparticles have drawn particular interest in cancer treatment, as they offer significant advantages over both common imaging contrast agents and chemotherapeutic drugs. However, the development of platforms for theranostic applications raises critical questions; is the <span class="hlt">optimal</span> <span class="hlt">particle</span> for therapy also the <span class="hlt">optimal</span> <span class="hlt">particle</span> for diagnostics? Are the specific characteristics needed to <span class="hlt">optimize</span> diagnostic imaging parallel to those required for treatment applications? This issue is examined in the present study, by investigating the effect of the gold nanoparticle (GNP) size on tumor uptake and tumor imaging. A series of anti-epidermal growth factor receptor conjugated GNPs of different sizes (diameter range: 20-120 nm) was synthesized, and then their uptake by human squamous cell carcinoma head and neck cancer cells, in vitro and in vivo, as well as their tumor visualization capabilities were evaluated using CT. The results showed that the size of the nanoparticle plays an instrumental role in determining its potential activity in vivo. Interestingly, we found that although the highest tumor uptake was obtained with 20 nm C225-GNPs, the highest contrast enhancement in the tumor was obtained with 50 nm C225-GNPs, thus leading to the conclusion that the <span class="hlt">optimal</span> <span class="hlt">particle</span> size for drug delivery is not necessarily <span class="hlt">optimal</span> for imaging. These findings stress the importance of the investigation and design of <span class="hlt">optimal</span> nanoparticles for theranostic applications.Theranostics is defined as the combination of therapeutic and diagnostic capabilities in the same agent. Nanotechnology is emerging as an efficient platform for theranostics, since nanoparticle-based contrast agents are powerful tools for enhancing in vivo imaging, while therapeutic nanoparticles may overcome several limitations of conventional drug delivery systems. Theranostic nanoparticles have drawn particular interest in cancer treatment, as they offer significant advantages over both common imaging contrast agents and chemotherapeutic drugs. However, the development of platforms for theranostic applications raises critical questions; is the <span class="hlt">optimal</span> <span class="hlt">particle</span> for therapy also the <span class="hlt">optimal</span> <span class="hlt">particle</span> for diagnostics? Are the specific characteristics needed to <span class="hlt">optimize</span> diagnostic imaging parallel to those required for treatment applications? This issue is examined in the present study, by investigating the effect of the gold nanoparticle (GNP) size on tumor uptake and tumor imaging. A series of anti-epidermal growth factor receptor conjugated GNPs of different sizes (diameter range: 20-120 nm) was synthesized, and then their uptake by human squamous cell carcinoma head and neck cancer cells, in vitro and in vivo, as well as their tumor visualization capabilities were evaluated using CT. The results showed that the size of the nanoparticle plays an instrumental role in determining its potential activity in vivo. Interestingly, we found that although the highest tumor uptake was obtained with 20 nm C225-GNPs, the highest contrast enhancement in the tumor was obtained with 50 nm C225-GNPs, thus leading to the conclusion that the <span class="hlt">optimal</span> <span class="hlt">particle</span> size for drug delivery is not necessarily <span class="hlt">optimal</span> for imaging. These findings stress the importance of the investigation and design of <span class="hlt">optimal</span> nanoparticles for theranostic applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03119b</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=81405&keyword=real+AND+options&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=59671013&CFTOKEN=53746085','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=81405&keyword=real+AND+options&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=59671013&CFTOKEN=53746085"><span id="translatedtitle">EFFECT OF VENTILATION SYSTEMS AND AIR <span class="hlt">FILTERS</span> ON DECAY RATES OF <span class="hlt">PARTICLES</span> PRODUCED BY INDOOR SOURCES IN AN OCCUPIED TOWNHOUSE</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Several studies have shown the importance of <span class="hlt">particle</span> losses in real homes due to deposition and filtration; however, none have quantitatively shown the impact of using a central forced air fan and in-duct <span class="hlt">filter</span> on <span class="hlt">particle</span> loss rates. In an attempt to provide such data, we me...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010LNCS.6466..506Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010LNCS.6466..506Z"><span id="translatedtitle"><span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> with Watts-Strogatz Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, Zhuanghua</p> <p></p> <p><span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> (PSO) is a popular swarm intelligent methodology by simulating the animal social behaviors. Recent study shows that this type of social behaviors is a complex system, however, for most variants of PSO, all individuals lie in a fixed topology, and conflict this natural phenomenon. Therefore, in this paper, a new variant of PSO combined with Watts-Strogatz small-world topology model, called WSPSO, is proposed. In WSPSO, the topology is changed according to Watts-Strogatz rules within the whole evolutionary process. Simulation results show the proposed algorithm is effective and efficient.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/962257','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/962257"><span id="translatedtitle">Generating <span class="hlt">optimal</span> initial conditions for smooth <span class="hlt">particle</span> hydrodynamics (SPH) simulations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Diehl, Steven; Rockefeller, Gabriel M; Fryer, Christopher L</p> <p>2008-01-01</p> <p>We present a new <span class="hlt">optimal</span> method to set up initial conditions for Smooth <span class="hlt">Particle</span> Hydrodynamics Simulations, which may also be of interest for N-body simulations. This new method is based on weighted Voronoi tesselations (WVTs) and can meet arbitrarily complex spatial resolution requirements. We conduct a comprehensive review of existing SPH setup methods, and outline their advantages, limitations and drawbacks. A serial version of our WVT setup method is publicly available and we give detailed instruction on how to easily implement the new method on top of an existing parallel SPH code.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JEI....22d1123C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JEI....22d1123C"><span id="translatedtitle">Panorama parking assistant system with improved <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cheng, Ruzhong; Zhao, Yong; Li, Zhichao; Jiang, Weigang; Wang, Xin'an; Xu, Yong</p> <p>2013-10-01</p> <p>A panorama parking assistant system (PPAS) for the automotive aftermarket together with a practical improved <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> method (IPSO) are proposed in this paper. In the PPAS system, four fisheye cameras are installed in the vehicle with different views, and four channels of video frames captured by the cameras are processed as a 360-deg top-view image around the vehicle. Besides the embedded design of PPAS, the key problem for image distortion correction and mosaicking is the efficiency of parameter <span class="hlt">optimization</span> in the process of camera calibration. In order to address this problem, an IPSO method is proposed. Compared with other parameter <span class="hlt">optimization</span> methods, the proposed method allows a certain range of dynamic change for the intrinsic and extrinsic parameters, and can exploit only one reference image to complete all of the <span class="hlt">optimization</span>; therefore, the efficiency of the whole camera calibration is increased. The PPAS is commercially available, and the IPSO method is a highly practical way to increase the efficiency of the installation and the calibration of PPAS in automobile 4S shops.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19933014','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19933014"><span id="translatedtitle">Deform PF-MT: <span class="hlt">particle</span> <span class="hlt">filter</span> with mode tracker for tracking nonaffine contour deformations.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vaswani, Namrata; Rathi, Yogesh; Yezzi, Anthony; Tannenbaum, Allen</p> <p>2010-04-01</p> <p>We propose algorithms for tracking the boundary contour of a deforming object from an image sequence, when the nonaffine (local) deformation over consecutive frames is large and there is overlapping clutter, occlusions, low contrast, or outlier imagery. When the object is arbitrarily deforming, each, or at least most, contour points can move independently. Contour deformation then forms an infinite (in practice, very large), dimensional space. Direct application of <span class="hlt">particle</span> <span class="hlt">filters</span> (PF) for large dimensional problems is impractically expensive. However, in most real problems, at any given time, most of the contour deformation occurs in a small number of dimensions ("effective basis space") while the residual deformation in the rest of the state space ("residual space") is small. This property enables us to apply the <span class="hlt">particle</span> <span class="hlt">filtering</span> with mode tracking (PF-MT) idea that was proposed for such large dimensional problems in recent work. Since most contour deformation is low spatial frequency, we propose to use the space of deformation at a subsampled set of locations as the effective basis space. The resulting algorithm is called deform PF-MT. It requires significant modifications compared to the original PF-MT because the space of contours is a non-Euclidean infinite dimensional space. PMID:19933014</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014E%26ES...17a2126B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014E%26ES...17a2126B"><span id="translatedtitle">Assimilation of microwave brightness temperatures for soil moisture estimation using <span class="hlt">particle</span> <span class="hlt">filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bi, H. Y.; Ma, J. W.; Qin, S. X.; Zeng, J. Y.</p> <p>2014-03-01</p> <p>Soil moisture plays a significant role in global water cycles. Both model simulations and remote sensing observations have their limitations when estimating soil moisture on a large spatial scale. Data assimilation (DA) is a promising tool which can combine model dynamics and remote sensing observations to obtain more precise ground soil moisture distribution. Among various DA methods, the <span class="hlt">particle</span> <span class="hlt">filter</span> (PF) can be applied to non-linear and non-Gaussian systems, thus holding great potential for DA. In this study, a data assimilation scheme based on the residual resampling <span class="hlt">particle</span> <span class="hlt">filter</span> (RR-PF) was developed to assimilate microwave brightness temperatures into the macro-scale semi-distributed Variance Infiltration Capacity (VIC) Model to estimate surface soil moisture. A radiative transfer model (RTM) was used to link brightness temperatures with surface soil moisture. Finally, the data assimilation scheme was validated by experimental data obtained at Arizona during the Soil Moisture Experiment 2004 (SMEX04). The results show that the estimation accuracy of soil moisture can be improved significantly by RR-PF through assimilating microwave brightness temperatures into VIC model. Both the overall trends and specific values of the assimilation results are more consistent with ground observations compared with model simulation results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.8128N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.8128N"><span id="translatedtitle">Streamflow data assimilation for the mesoscale hydrologic model (mHM) using <span class="hlt">particle</span> <span class="hlt">filtering</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Noh, Seong Jin; Rakovec, Oldrich; Kumar, Rohini; Samaniego, Luis; Choi, Shin-woo</p> <p>2015-04-01</p> <p>Data assimilation has been becoming popular to increase the certainty of the hydrologic prediction considering various sources of uncertainty through the hydrologic modeling chain. In this study, we develop a data assimilation framework for the mesoscale hydrologic model (mHM 5.2, http://www.ufz.de/mhm) using <span class="hlt">particle</span> <span class="hlt">filtering</span>, which is a sequential DA method for non-linear and non-Gaussian models. The mHM is a grid based distributed model that is based on numerical approximations of dominant hydrologic processes having similarity with the HBV and VIC models. The developed DA framework for the mHM represents simulation uncertainty by model ensembles and updates spatial distributions of model state variables when new observations are available in each updating time interval. The evaluation of the proposed method is carried out within several large European basins via assimilating multiple streamflow measurements in a daily interval. Dimensional limitations of <span class="hlt">particle</span> <span class="hlt">filtering</span> is resolved by effective noise specification methods, which uses spatial and temporal correlation of weather forcing data to represent model structural uncertainty. The presentation will be focused on gains and limitations of streamflow data assimilation in several hindcasting experiments. In addition, impacts of non-Gaussian distributions of state variables on model performance will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H41A0773Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H41A0773Y"><span id="translatedtitle">Improving Hydrologic Data Assimilation by a Multivariate <span class="hlt">Particle</span> <span class="hlt">Filter</span>-Markov Chain Monte Carlo</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yan, H.; DeChant, C. M.; Moradkhani, H.</p> <p>2014-12-01</p> <p>Data assimilation (DA) is a popular method for merging information from multiple sources (i.e. models and remotely sensing), leading to improved hydrologic prediction. With the increasing availability of satellite observations (such as soil moisture) in recent years, DA is emerging in operational forecast systems. Although these techniques have seen widespread application, developmental research has continued to further refine their effectiveness. This presentation will examine potential improvements to the <span class="hlt">Particle</span> <span class="hlt">Filter</span> (PF) through the inclusion of multivariate correlation structures. Applications of the PF typically rely on univariate DA schemes (such as assimilating the outlet observed discharge), and multivariate schemes generally ignore the spatial correlation of the observations. In this study, a multivariate DA scheme is proposed by introducing geostatistics into the newly developed <span class="hlt">particle</span> <span class="hlt">filter</span> with Markov chain Monte Carlo (PF-MCMC) method. This new method is assessed by a case study over one of the basin with natural hydrologic process in Model Parameter Estimation Experiment (MOPEX), located in Arizona. The multivariate PF-MCMC method is used to assimilate the Advanced Scatterometer (ASCAT) grid (12.5 km) soil moisture retrievals and the observed streamflow in five gages (four inlet and one outlet gages) into the Sacramento Soil Moisture Accounting (SAC-SMA) model for the same scale (12.5 km), leading to greater skill in hydrologic predictions.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMNS41A..02F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMNS41A..02F"><span id="translatedtitle">What is <span class="hlt">Particle</span> Swarm <span class="hlt">optimization</span>? Application to hydrogeophysics (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fernández Martïnez, J.; García Gonzalo, E.; Mukerji, T.</p> <p>2009-12-01</p> <p>Inverse problems are generally ill-posed. This yields lack of uniqueness and/or numerical instabilities. These features cause local <span class="hlt">optimization</span> methods without prior information to provide unpredictable results, not being able to discriminate among the multiple models consistent with the end criteria. Stochastic approaches to inverse problems consist in shifting attention to the probability of existence of certain interesting subsurface structures instead of "looking for a unique model". Some well-known stochastic methods include genetic algorithms and simulated annealing. A more recent method, <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span>, is a global <span class="hlt">optimization</span> technique that has been successfully applied to solve inverse problems in many engineering fields, although its use in geosciences is still limited. Like all stochastic methods, PSO requires reasonably fast forward modeling. The basic idea behind PSO is that each model searches the model space according to its misfit history and the misfit of the other models of the swarm. PSO algorithm can be physically interpreted as a damped spring-mass system. This physical analogy was used to define a whole family of PSO <span class="hlt">optimizers</span> and to establish criteria, based on the stability of <span class="hlt">particle</span> swarm trajectories, to tune the PSO parameters: inertia, local and global accelerations. In this contribution we show application to different low-cost hydrogeophysical inverse problems: 1) a salt water intrusion problem using Vertical Electrical Soundings, 2) the inversion of Spontaneous Potential data for groundwater modeling, 3) the identification of Cole-Cole parameters for Induced Polarization data. We show that with this stochastic approach we are able to answer questions related to risk analysis, such as what is the depth of the salt intrusion with a certain probability, or giving probabilistic bounds for the water table depth. Moreover, these measures of uncertainty are obtained with small computational cost and time, allowing us a very dynamical and practical analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4730493','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4730493"><span id="translatedtitle">Experimental Study on Ultrafine <span class="hlt">Particle</span> Removal Performance of Portable Air Cleaners with Different <span class="hlt">Filters</span> in an Office Room</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ma, Huan; Shen, Henggen; Shui, Tiantian; Li, Qing; Zhou, Liuke</p> <p>2016-01-01</p> <p>Size- and time-dependent aerodynamic behaviors of indoor <span class="hlt">particles</span>, including PM1.0, were evaluated in a school office in order to test the performance of air-cleaning devices using different <span class="hlt">filters</span>. In-situ real-time measurements were taken using an optical <span class="hlt">particle</span> counter. The filtration characteristics of <span class="hlt">filter</span> media, including single-pass efficiency, volume and effectiveness, were evaluated and analyzed. The electret <span class="hlt">filter</span> (EE) medium shows better initial removal efficiency than the high efficiency (HE) medium in the 0.3–3.5 μm <span class="hlt">particle</span> size range, while under the same face velocity, the filtration resistance of the HE medium is several times higher than that of the EE medium. During service life testing, the efficiency of the EE medium decreased to 60% with a total purifying air flow of 25 × 104 m3/m2. The resistance curve rose slightly before the efficiency reached the bottom, and then increased almost exponentially. The single-pass efficiency of portable air cleaner (PAC) with the pre-<span class="hlt">filter</span> (PR) or the active carbon granule <span class="hlt">filter</span> (CF) was relatively poor. While PAC with the pre-<span class="hlt">filter</span> and the high efficiency <span class="hlt">filter</span> (PR&HE) showed maximum single-pass efficiency for PM1.0 (88.6%), PAC with the HE was the most effective at removing PM1.0. The enhancement of PR with HE and electret <span class="hlt">filters</span> augmented the single-pass efficiency, but lessened the airflow rate and effectiveness. Combined with PR, the decay constant of large-sized <span class="hlt">particles</span> could be greater than for PACs without PR. Without regard to the lifetime, the electret <span class="hlt">filters</span> performed better with respect to resource saving and purification improvement. A most penetrating <span class="hlt">particle</span> size range (MPPS: 0.4–0.65 μm) exists in both HE and electret <span class="hlt">filters</span>; the MPPS tends to become larger after HE and electret <span class="hlt">filters</span> are combined with PR. These results serve to provide a better understanding of the indoor <span class="hlt">particle</span> removal performance of PACs when combined with different kinds of <span class="hlt">filters</span> in school office buildings. PMID:26742055</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26742055','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26742055"><span id="translatedtitle">Experimental Study on Ultrafine <span class="hlt">Particle</span> Removal Performance of Portable Air Cleaners with Different <span class="hlt">Filters</span> in an Office Room.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ma, Huan; Shen, Henggen; Shui, Tiantian; Li, Qing; Zhou, Liuke</p> <p>2016-01-01</p> <p>Size- and time-dependent aerodynamic behaviors of indoor <span class="hlt">particles</span>, including PM1.0, were evaluated in a school office in order to test the performance of air-cleaning devices using different <span class="hlt">filters</span>. In-situ real-time measurements were taken using an optical <span class="hlt">particle</span> counter. The filtration characteristics of <span class="hlt">filter</span> media, including single-pass efficiency, volume and effectiveness, were evaluated and analyzed. The electret <span class="hlt">filter</span> (EE) medium shows better initial removal efficiency than the high efficiency (HE) medium in the 0.3-3.5 μm <span class="hlt">particle</span> size range, while under the same face velocity, the filtration resistance of the HE medium is several times higher than that of the EE medium. During service life testing, the efficiency of the EE medium decreased to 60% with a total purifying air flow of 25 × 10⁴ m³/m². The resistance curve rose slightly before the efficiency reached the bottom, and then increased almost exponentially. The single-pass efficiency of portable air cleaner (PAC) with the pre-<span class="hlt">filter</span> (PR) or the active carbon granule <span class="hlt">filter</span> (CF) was relatively poor. While PAC with the pre-<span class="hlt">filter</span> and the high efficiency <span class="hlt">filter</span> (PR&HE) showed maximum single-pass efficiency for PM1.0 (88.6%), PAC with the HE was the most effective at removing PM1.0. The enhancement of PR with HE and electret <span class="hlt">filters</span> augmented the single-pass efficiency, but lessened the airflow rate and effectiveness. Combined with PR, the decay constant of large-sized <span class="hlt">particles</span> could be greater than for PACs without PR. Without regard to the lifetime, the electret <span class="hlt">filters</span> performed better with respect to resource saving and purification improvement. A most penetrating <span class="hlt">particle</span> size range (MPPS: 0.4-0.65 μm) exists in both HE and electret <span class="hlt">filters</span>; the MPPS tends to become larger after HE and electret <span class="hlt">filters</span> are combined with PR. These results serve to provide a better understanding of the indoor <span class="hlt">particle</span> removal performance of PACs when combined with different kinds of <span class="hlt">filters</span> in school office buildings. PMID:26742055</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23470039','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23470039"><span id="translatedtitle"><span class="hlt">Filterable</span> redox cycling activity: a comparison between diesel exhaust <span class="hlt">particles</span> and secondary organic aerosol constituents.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McWhinney, Robert D; Badali, Kaitlin; Liggio, John; Li, Shao-Meng; Abbatt, Jonathan P D</p> <p>2013-04-01</p> <p>The redox activity of diesel exhaust <span class="hlt">particles</span> (DEP) collected from a light-duty diesel passenger car engine was examined using the dithiothreitol (DTT) assay. DEP was highly redox-active, causing DTT to decay at a rate of 23-61 pmol min(-1) μg(-1) of <span class="hlt">particle</span> used in the assay, which was an order of magnitude higher than ambient coarse and fine particulate matter (PM) collected from downtown Toronto. Only 2-11% of the redox activity was in the water-soluble portion, while the remainder occurred at the black carbon surface. This is in contrast to redox-active secondary organic aerosol constituents, in which upward of 90% of the activity occurs in the water-soluble fraction. The redox activity of DEP is not extractable by moderately polar (methanol) and nonpolar (dichloromethane) organic solvents, and is hypothesized to arise from redox-active moieties contiguous with the black carbon portion of the <span class="hlt">particles</span>. These measurements illustrate that "<span class="hlt">Filterable</span> Redox Cycling Activity" may therefore be useful to distinguish black carbon-based oxidative capacity from water-soluble organic-based activity. The difference in chemical environment leading to redox activity highlights the need to further examine the relationship between activity in the DTT assay and toxicology measurements across <span class="hlt">particles</span> of different origins and composition. PMID:23470039</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPRS..114...10W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPRS..114...10W"><span id="translatedtitle">Modified patch-based locally <span class="hlt">optimal</span> Wiener method for interferometric SAR phase <span class="hlt">filtering</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Yang; Huang, Haifeng; Dong, Zhen; Wu, Manqing</p> <p>2016-04-01</p> <p>This paper presents a modified patch-based locally <span class="hlt">optimal</span> Wiener (PLOW) method for interferometric synthetic aperture radar (InSAR) phase <span class="hlt">filtering</span>. PLOW is a linear minimum mean squared error (LMMSE) estimator based on a Gaussian additive noise condition. It jointly estimates moments, including mean and covariance, using a non-local technique. By using similarities between image patches, this method can effectively <span class="hlt">filter</span> noise while preserving details. When applied to InSAR phase <span class="hlt">filtering</span>, three modifications are proposed based on spatial variant noise. First, pixels are adaptively clustered according to their coherence magnitudes. Second, rather than a global estimator, a locally adaptive estimator is used to estimate noise covariance. Third, using the coherence magnitudes as weights, the mean of each cluster is estimated, using a weighted mean to further reduce noise. The performance of the proposed method is experimentally verified using simulated and real data. The results of our study demonstrate that the proposed method is on par or better than the non-local interferometric SAR (NL-InSAR) method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1757777','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1757777"><span id="translatedtitle">Bronchoalveolar inflammation after exposure to diesel exhaust: comparison between unfiltered and <span class="hlt">particle</span> trap <span class="hlt">filtered</span> exhaust</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rudell, B.; Blomberg, A.; Helleday, R.; Ledin, M. C.; Lundback, B.; Stjernberg, N.; Horstedt, P.; Sandstrom, T.</p> <p>1999-01-01</p> <p>OBJECTIVES: Air pollution particulates have been identified as having adverse effects on respiratory health. The present study was undertaken to further clarify the effects of diesel exhaust on bronchoalveolar cells and soluble components in normal healthy subjects. The study was also designed to evaluate whether a ceramic <span class="hlt">particle</span> trap at the end of the tail pipe, from an idling engine, would reduce indices of airway inflammation. METHODS: The study comprised three exposures in all 10 healthy never smoking subjects; air, diluted diesel exhaust, and diluted diesel exhaust <span class="hlt">filtered</span> with a ceramic <span class="hlt">particle</span> trap. The exposures were given for 1 hour in randomised order about 3 weeks apart. The diesel exhaust exposure apperatus has previously been carefully developed and evaluated. Bronchoalveolar lavage was performed 24 hours after exposures and the lavage fluids from the bronchial and bronchoalveolar region were analysed for cells and soluble components. RESULTS: The <span class="hlt">particle</span> trap reduced the mean steady state number of <span class="hlt">particles</span> by 50%, but the concentrations of the other measured compounds were almost unchanged. It was found that diesel exhaust caused an increase in neutrophils in airway lavage, together with an adverse influence on the phagocytosis by alveolar macrophages in vitro. Furthermore, the diesel exhaust was found to be able to induce a migration of alveolar macrophages into the airspaces, together with reduction in CD3+CD25+ cells. (CD = cluster of differentiation) The use of the specific ceramic <span class="hlt">particle</span> trap at the end of the tail pipe was not sufficient to completely abolish these effects when interacting with the exhaust from an idling vehicle. CONCLUSIONS: The current study showed that exposure to diesel exhaust may induce neutrophil and alveolar macrophage recruitment into the airways and suppress alveolar macrophage function. The <span class="hlt">particle</span> trap did not cause significant reduction of effects induced by diesel exhaust compared with unfiltered diesel exhaust. Further studies are warranted to evaluate more efficient treatment devices to reduce adverse reactions to diesel exhaust in the airways. PMID:10492649</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010LNCS.6466..639S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010LNCS.6466..639S"><span id="translatedtitle">Security Constrained <span class="hlt">Optimal</span> Power Flow with FACTS Devices Using Modified <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Somasundaram, P.; Muthuselvan, N. B.</p> <p></p> <p>This paper presents new computationally efficient improved <span class="hlt">Particle</span> Swarm algorithms for solving Security Constrained <span class="hlt">Optimal</span> Power Flow (SCOPF) in power systems with the inclusion of FACTS devices. The proposed algorithms are developed based on the combined application of Gaussian and Cauchy Probability distribution functions incorporated in <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO). The power flow algorithm with the presence of Static Var Compensator (SVC) Thyristor Controlled Series Capacitor (TCSC) and Unified Power Flow Controller (UPFC), has been formulated and solved. The proposed algorithms are tested on standard IEEE 30-bus system. The analysis using PSO and modified PSO reveals that the proposed algorithms are relatively simple, efficient, reliable and suitable for real-time applications. And these algorithms can provide accurate solution with fast convergence and have the potential to be applied to other power engineering problems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhCS.645a2018C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhCS.645a2018C"><span id="translatedtitle">Towards <span class="hlt">Optimal</span> <span class="hlt">Filtering</span> on ARM for ATLAS Tile Calorimeter Front-End Processing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cox, Mitchell A.</p> <p>2015-10-01</p> <p>The Large Hadron Collider at CERN generates enormous amounts of raw data which presents a serious computing challenge. After planned upgrades in 2022, the data output from the ATLAS Tile Calorimeter will increase by 200 times to over 40 Tb/s. Advanced and characteristically expensive Digital Signal Processors (DSPs) and Field Programmable Gate Arrays (FPGAs) are currently used to process this quantity of data. It is proposed that a cost- effective, high data throughput Processing Unit (PU) can be developed by using several ARM System on Chips in a cluster configuration to allow aggregated processing performance and data throughput while maintaining minimal software design difficulty for the end-user. ARM is a cost effective and energy efficient alternative CPU architecture to the long established x86 architecture. This PU could be used for a variety of high-level algorithms on the high data throughput raw data. An <span class="hlt">Optimal</span> <span class="hlt">Filtering</span> algorithm has been implemented in C++ and several ARM platforms have been tested. <span class="hlt">Optimal</span> <span class="hlt">Filtering</span> is currently used in the ATLAS Tile Calorimeter front-end for basic energy reconstruction and is currently implemented on DSPs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/790968','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/790968"><span id="translatedtitle"><span class="hlt">OPTIMIZATION</span> OF COAL <span class="hlt">PARTICLE</span> FLOW PATTERNS IN LOW NOX BURNERS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jost O.L. Wendt; Gregory E. Ogden; Jennifer Sinclair; Caner Yurteri</p> <p>2001-08-20</p> <p>The proposed research is directed at evaluating the effect of flame aerodynamics on NO{sub x} emissions from coal fired burners in a systematic manner. This fundamental research includes both experimental and modeling efforts being performed at the University of Arizona in collaboration with Purdue University. The objective of this effort is to develop rational design tools for <span class="hlt">optimizing</span> low NO{sub x} burners to the kinetic emissions limit (below 0.2 lb./MMBTU). Experimental studies include both cold and hot flow evaluations of the following parameters: flame holder geometry, secondary air swirl, primary and secondary inlet air velocity, coal concentration in the primary air and coal <span class="hlt">particle</span> size distribution. Hot flow experiments will also evaluate the effect of wall temperature on burner performance. Cold flow studies will be conducted with surrogate <span class="hlt">particles</span> as well as pulverized coal. The cold flow furnace will be similar in size and geometry to the hot-flow furnace but will be designed to use a laser Doppler velocimeter/phase Doppler <span class="hlt">particle</span> size analyzer. The results of these studies will be used to predict <span class="hlt">particle</span> trajectories in the hot-flow furnace as well as to estimate the effect of flame holder geometry on furnace flow field. The hot-flow experiments will be conducted in a novel near-flame down-flow pulverized coal furnace. The furnace will be equipped with externally heated walls. Both reactors will be sized to minimize wall effects on <span class="hlt">particle</span> flow fields. The cold-flow results will be compared with Fluent computation fluid dynamics model predictions and correlated with the hot-flow results with the overall goal of providing insight for novel low NO{sub x} burner geometry's.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JHyd..514..249R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JHyd..514..249R"><span id="translatedtitle"><span class="hlt">Optimal</span> hydrograph separation <span class="hlt">filter</span> to evaluate transport routines of hydrological models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rimmer, Alon; Hartmann, Andreas</p> <p>2014-06-01</p> <p>Hydrograph separation (HS) using recursive digital <span class="hlt">filter</span> approaches focuses on trying to distinguish between the rapidly occurring discharge components like surface runoff, and the slowly changing discharge originating from interflow and groundwater. <span class="hlt">Filter</span> approaches are mathematical procedures, which perform the HS using a set of separation parameters. The first goal of this study is to minimize the subjective influence that a user of the <span class="hlt">filter</span> technique exerts on the results by the choice of such <span class="hlt">filter</span> parameters. A simple <span class="hlt">optimal</span> HS (OHS) technique for the estimation of the separation parameters was introduced, relying on measured stream hydrochemistry. The second goal is to use the OHS parameters to benchmark the performance of process-based hydro-geochemical (HG) models. The new HG routine can be used to quantify the degree of knowledge that the stream flow time series itself contributes to the HG analysis, using newly developed benchmark geochemistry efficiency (BGE). Results of the OHS show that the two HS fractions (“rapid” and “slow”) differ according to the HG substances which were selected. The BFImax parameter (long-term ratio of baseflow to total streamflow) ranged from 0.26 to 0.94 for SO4-2 and total suspended solids, TSS, respectively. Then, predictions of SO4-2 transport from a process-based hydrological model were benchmarked with the proposed HG routine, in order to evaluate the significance of the HG routines in the process-based model. This comparison provides valuable quality test that would not be obvious when using the traditional measures like r2 or the NSE (Nash-Sutcliffe efficiency). The process-based model resulted in r2 = 0.65 and NSE = 0.65, while the benchmark routine results were slightly lower with r2 = 0.61 and NSE = 0.58. However, the comparison between the two model resulted in obvious advantage for the process-based model with BGE = 0.15.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JPhCS.385a2012W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JPhCS.385a2012W"><span id="translatedtitle">GPU-Based Asynchronous Global <span class="hlt">Optimization</span> with <span class="hlt">Particle</span> Swarm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wachowiak, M. P.; Lambe Foster, A. E.</p> <p>2012-10-01</p> <p>The recent upsurge in research into general-purpose applications for graphics processing units (GPUs) has made low cost high-performance computing increasingly more accessible. Many global <span class="hlt">optimization</span> algorithms that have previously benefited from parallel computation are now poised to take advantage of general-purpose GPU computing as well. In this paper, a global parallel asynchronous <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO) approach is employed to solve three relatively complex, realistic parameter estimation problems in which each processor performs significant computation. Although PSO is readily parallelizable, memory bandwidth limitations with GPUs must be addressed, which is accomplished by minimizing communication among individual population members though asynchronous operations. The effect of asynchronous PSO on robustness and efficiency is assessed as a function of problem and population size. Experiments were performed with different population sizes on NVIDIA GPUs and on single-core CPUs. Results for successful trials exhibit marked speedup increases with the population size, indicating that more <span class="hlt">particles</span> may be used to improve algorithm robustness while maintaining nearly constant time. This work also suggests that asynchronous operations on the GPU may be viable in stochastic population-based algorithms to increase efficiency without sacrificing the quality of the solutions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24108491','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24108491"><span id="translatedtitle">A scatter learning <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> algorithm for multimodal problems.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ren, Zhigang; Zhang, Aimin; Wen, Changyun; Feng, Zuren</p> <p>2014-07-01</p> <p><span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> (PSO) has been proved to be an effective tool for function <span class="hlt">optimization</span>. Its performance depends heavily on the characteristics of the employed exemplars. This necessitates considering both the fitness and the distribution of exemplars in designing PSO algorithms. Following this idea, we propose a novel PSO variant, called scatter learning PSO algorithm (SLPSOA) for multimodal problems. SLPSOA contains some new algorithmic features while following the basic framework of PSO. It constructs an exemplar pool (EP) that is composed of a certain number of relatively high-quality solutions scattered in the solution space, and requires <span class="hlt">particles</span> to select their exemplars from EP using the roulette wheel rule. By this means, more promising solution regions can be found. In addition, SLPSOA employs Solis and Wets' algorithm as a local searcher to enhance its fine search ability in the newfound solution regions. To verify the efficiency of the proposed algorithm, we test it on a set of 16 benchmark functions and compare it with six existing typical PSO algorithms. Computational results demonstrate that SLPSOA can prevent premature convergence and produce competitive solutions. PMID:24108491</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015OEng....5...31D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015OEng....5...31D"><span id="translatedtitle"><span class="hlt">Optimal</span> high speed CMOS inverter design using craziness based <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> Algorithm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>De, Bishnu P.; Kar, Rajib; Mandal, Durbadal; Ghoshal, Sakti P.</p> <p>2015-07-01</p> <p>The inverter is the most fundamental logic gate that performs a Boolean operation on a single input variable. In this paper, an <span class="hlt">optimal</span> design of CMOS inverter using an improved version of <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> technique called Craziness based <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (CRPSO) is proposed. CRPSO is very simple in concept, easy to implement and computationally efficient algorithm with two main advantages: it has fast, nearglobal convergence, and it uses nearly robust control parameters. The performance of PSO depends on its control parameters and may be influenced by premature convergence and stagnation problems. To overcome these problems the PSO algorithm has been modiffed to CRPSO in this paper and is used for CMOS inverter design. In birds' flocking or ffsh schooling, a bird or a ffsh often changes direction suddenly. In the proposed technique, the sudden change of velocity is modelled by a direction reversal factor associated with the previous velocity and a "craziness" velocity factor associated with another direction reversal factor. The second condition is introduced depending on a predeffned craziness probability to maintain the diversity of <span class="hlt">particles</span>. The performance of CRPSO is compared with real code.gnetic algorithm (RGA), and conventional PSO reported in the recent literature. CRPSO based design results are also compared with the PSPICE based results. The simulation results show that the CRPSO is superior to the other algorithms for the examples considered and can be efficiently used for the CMOS inverter design.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/638543','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/638543"><span id="translatedtitle">Effects of fan cycling on the <span class="hlt">particle</span> shedding of particulate air <span class="hlt">filters</span> used for IAQ control. Report for January--July 1996</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kuehn, T.H.; Yang, C.H.; Kulp, R.N.</p> <p>1998-08-01</p> <p>The purpose of the present study is to investigate the effect of fan cycling on two types of bag <span class="hlt">filters</span>. Total <span class="hlt">particle</span> concentrations and viable bioaerosol concentrations were measured upstream and downstream of the <span class="hlt">filters</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4032252','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4032252"><span id="translatedtitle"><span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> with Scale-Free Interactions</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Liu, Chen; Du, Wen-Bo; Wang, Wen-Xu</p> <p>2014-01-01</p> <p>The <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO) algorithm, in which individuals collaborate with their interacted neighbors like bird flocking to search for the optima, has been successfully applied in a wide range of fields pertaining to searching and convergence. Here we employ the scale-free network to represent the inter-individual interactions in the population, named SF-PSO. In contrast to the traditional PSO with fully-connected topology or regular topology, the scale-free topology used in SF-PSO incorporates the diversity of individuals in searching and information dissemination ability, leading to a quite different <span class="hlt">optimization</span> process. Systematic results with respect to several standard test functions demonstrate that SF-PSO gives rise to a better balance between the convergence speed and the optimum quality, accounting for its much better performance than that of the traditional PSO algorithms. We further explore the dynamical searching process microscopically, finding that the cooperation of hub nodes and non-hub nodes play a crucial role in <span class="hlt">optimizing</span> the convergence process. Our work may have implications in computational intelligence and complex networks. PMID:24859007</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhDT.......163H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhDT.......163H"><span id="translatedtitle">Adaptive Resampling <span class="hlt">Particle</span> <span class="hlt">Filters</span> for GPS Carrier-Phase Navigation and Collision Avoidance System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hwang, Soon Sik</p> <p></p> <p>This dissertation addresses three problems: 1) adaptive resampling technique (ART) for <span class="hlt">Particle</span> <span class="hlt">Filters</span>, 2) precise relative positioning using Global Positioning System (GPS) Carrier-Phase (CP) measurements applied to nonlinear integer resolution problem for GPS CP navigation using <span class="hlt">Particle</span> <span class="hlt">Filters</span>, and 3) collision detection system based on GPS CP broadcasts. First, Monte Carlo <span class="hlt">filters</span>, called <span class="hlt">Particle</span> <span class="hlt">Filters</span> (PF), are widely used where the system is non-linear and non-Gaussian. In real-time applications, their estimation accuracies and efficiencies are significantly affected by the number of <span class="hlt">particles</span> and the scheduling of relocating weights and samples, the so-called resampling step. In this dissertation, the appropriate number of <span class="hlt">particles</span> is estimated adaptively such that the error of the sample mean and variance stay in bounds. These bounds are given by the confidence interval of a normal probability distribution for a multi-variate state. Two required number of samples maintaining the mean and variance error within the bounds are derived. The time of resampling is determined when the required sample number for the variance error crosses the required sample number for the mean error. Second, the PF using GPS CP measurements with adaptive resampling is applied to precise relative navigation between two GPS antennas. In order to make use of CP measurements for navigation, the unknown number of cycles between GPS antennas, the so called integer ambiguity, should be resolved. The PF is applied to this integer ambiguity resolution problem where the relative navigation states estimation involves nonlinear observations and nonlinear dynamics equation. Using the PF, the probability density function of the states is estimated by sampling from the position and velocity space and the integer ambiguities are resolved without using the usual hypothesis tests to search for the integer ambiguity. The ART manages the number of position samples and the frequency of the resampling step for real-time kinematics GPS navigation. The experimental results demonstrate the performance of the ART and the insensitivity of the proposed approach to GPS CP cycle-slips. Third, the GPS has great potential for the development of new collision avoidance systems and is being considered for the next generation Traffic alert and Collision Avoidance System (TCAS). The current TCAS equipment, is capable of broadcasting GPS code information to nearby airplanes, and also, the collision avoidance system using the navigation information based on GPS code has been studied by researchers. In this dissertation, the aircraft collision detection system using GPS CP information is addressed. The PF with position samples is employed for the CP based relative position estimation problem and the same algorithm can be used to determine the vehicle attitude if multiple GPS antennas are used. For a reliable and enhanced collision avoidance system, three dimensional trajectories are projected using the estimates of the relative position, velocity, and the attitude. It is shown that the performance of GPS CP based collision detecting algorithm meets the accuracy requirements for a precise approach of flight for auto landing with significantly less unnecessary collision false alarms and no miss alarms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008SPIE.6623E..21L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008SPIE.6623E..21L"><span id="translatedtitle">Implementation and <span class="hlt">optimization</span> of an improved morphological <span class="hlt">filtering</span> algorithm for speckle removal based on DSPs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Qitao; Li, Yingchun; Sun, Huayan; Zhao, Yanzhong</p> <p>2008-03-01</p> <p>Laser active imaging system, which is of high resolution, anti-jamming and can be three-dimensional (3-D) imaging, has been used widely. But its imagery is usually affected by speckle noise which makes the grayscale of pixels change violently, hides the subtle details and makes the imaging resolution descend greatly. Removing speckle noise is one of the most difficult problems encountered in this system because of the poor statistical property of speckle. Based on the analysis of the statistical characteristic of speckle and morphological <span class="hlt">filtering</span> algorithm, in this paper, an improved multistage morphological <span class="hlt">filtering</span> algorithm is studied and implemented on TMS320C6416 DSP. The algorithm makes the morphological open-close and close-open transformation by using two different linear structure elements respectively, and then takes a weighted average over the above transformational results. The weighted coefficients are decided by the statistical characteristic of speckle. This algorithm is implemented on the TMS320C6416 DSPs after simulation on computer. The procedure of software design is fully presented. The methods are fully illustrated to achieve and <span class="hlt">optimize</span> the algorithm in the research of the structural characteristic of TMS320C6416 DSP and feature of the algorithm. In order to fully benefit from such devices and increase the performance of the whole system, it is necessary to take a series of steps to <span class="hlt">optimize</span> the DSP programs. This paper introduces some effective methods, including refining code structure, eliminating memory dependence, <span class="hlt">optimizing</span> assembly code via linear assembly and so on, for TMS320C6x C language <span class="hlt">optimization</span> and then offers the results of the application in a real-time implementation. The results of processing to the images blurred by speckle noise shows that the algorithm can not only effectively suppress speckle noise but also preserve the geometrical features of images. The results of the <span class="hlt">optimized</span> code running on the DSP platform show that the <span class="hlt">optimized</span> outcome realizes better instruction-level parallelism and pipeline operation and the program is proved to be reliable, effective and high real time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMNG43A1572S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMNG43A1572S"><span id="translatedtitle">Numerical experiments with an implicit <span class="hlt">particle</span> <span class="hlt">filter</span> for the shallow water equations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Souopgui, I.; Chorin, A. J.; Hussaini, M.</p> <p>2012-12-01</p> <p>The estimation of initial conditions for the shallow water equations for a given set of later data is a well known test problem for data assimilation codes. A popular approach to this problem is the variational method (4D-Var), i.e. the computation of the mode of the posterior probability density function (pdf) via the adjoint technique. Here, we improve on 4D-Var by computing the conditional mean (the minimum least square error estimator) rather than the mode (a biased estimator) and we do so with implicit sampling, a Monte Carlo (MC) importance sampling method. The idea in implicit sampling is to first search for the high-probability region of the posterior pdf and then to find samples in this region. Because the samples are concentrated in the high-probability region, fewer samples are required than with competing MC schemes. The search for the high-probability region can be implemented by a minimization that is very similar to the minimization in 4D-Var, and we make use of a 4D-Var code in our implementation. The samples are obtained by solving algebraic equations with a random right-hand-side. These equations can be solved efficiently, so that the additional cost of our approach, compared to traditional 4D-Var, is small. The long-term goal is to assimilate experimental data, obtained with the CORIOLIS turntable in Grenoble (France), to study the drift of a vortex. We present results from numerical twin experiments as a first step towards our long-term goal. We discretize the shallow water equations on a square domain (2.5m× 2.5m) using finite differences on a staggered grid of size 28× 28 and a fourth order Runge-Kutta. We assume open boundary conditions and estimate the initial state (velocities and surface height) given noisy observations of the state. We solve the <span class="hlt">optimization</span> problem using a 4D-Var code that relies on a L-BFGS method; the random algebraic equations are solved with random maps, i.e. we look for solutions in given, but random, directions of the state space. In our numerical experiments, we varied the availability of the data (in both space and time) as well as the variance of the observation noise. We found that the implicit <span class="hlt">particle</span> <span class="hlt">filter</span> is reliable and efficient in all scenarios we considered. The implicit sampling method could improve the accuracy of the traditional variational approach. Moreover, we obtain quantitative measures of the uncertainty of the state estimate ``for free,'' while no information about the uncertainty is easily available using the traditional 4D-Var method only.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JPhCS.318g2019F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JPhCS.318g2019F"><span id="translatedtitle">A fast atmospheric turbulent parameters estimation using <span class="hlt">particle</span> <span class="hlt">filtering</span>. Application to LIDAR observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Florian, Suzat; Christophe, Baehr; Alain, Dabas</p> <p>2011-12-01</p> <p>Estimating fast turbulence fluctuations in the boundary layer of the atmosphere, using remote detection instrument is an important scientific issue. Doppler LIDAR, is typically used to get this kind of information because it can make fast, distant, precise, and non-intrusive measurements of the wind field by giving the radial component in any direction. The objective of those measurements is to evaluate as precisely as possible the wind structure using the partial wind information provided, in order to estimate turbulent parameters. The approach presented in this paper, consist in coupling the remote detection system and a stochastic Lagrangian model of the atmosphere. The fluid is represented by a set of interacting <span class="hlt">particles</span>, evolving according to an evolution system based on S.B Pope work. Data provided by the instrument are assimilated in real time in the model using a <span class="hlt">particle</span> <span class="hlt">filtering</span> algorithm. The purpose is to locally correct the properties of <span class="hlt">particles</span> using measurements, to fit the real fluid observed. A precise real time estimation of the wind field, allows then to estimate turbulent parameters. The methodology has produced convincing results on simulated Doppler LIDAR measurements, in tree-dimensional modeling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JAP...101c4302L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JAP...101c4302L"><span id="translatedtitle">Regular silicon pillars and dichroic <span class="hlt">filters</span> produced via <span class="hlt">particle</span>-imprinted membranes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ladenburger, Andreas; Reiser, Anton; Konle, Johannes; Feneberg, Martin; Sauer, Rolf; Thonke, Klaus; Yan, Feng; Goedel, Werner A.</p> <p>2007-02-01</p> <p>We have produced regular silicon pillar arrays and porous gold films on the 100 nm scale without any optical or e-beam lithography. Using <span class="hlt">particle</span>-assisted wetting we produced a nanoporous polymer membrane on silicon. The membrane incorporated a regular array of pores generated by embedding silica <span class="hlt">particles</span> in an organic liquid and subsequently removing the <span class="hlt">particles</span> after polymerization of the liquid. Gold vapor was deposited onto the silicon wafer coated by the porous polymer structure. This process created an array of gold dots on the substrate at the bottom of the pores, and at the same time, a sievelike porous gold layer on top of the polymer matrix. The top layer was lifted off and used as an optical short-pass <span class="hlt">filter</span>. After removal of the polymer membrane, the remaining gold dot pattern on the substrate served as a mask in a deep reactive ion etching process. We obtain large-area arrays of silicon nanopillars up to 1.5 μm in height and below 200 nm in diameter.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9091E..1IY','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9091E..1IY"><span id="translatedtitle">A Bayesian framework with an auxiliary <span class="hlt">particle</span> <span class="hlt">filter</span> for GMTI-based ground vehicle tracking aided by domain knowledge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, Miao; Liu, Cunjia; Chen, Wen-hua; Chambers, Jonathon</p> <p>2014-06-01</p> <p>In this work, we propose a new ground moving target indicator (GMTI) radar based ground vehicle tracking method which exploits domain knowledge. Multiple state models are considered and a Monte-Carlo sampling based algorithm is preferred due to the manoeuvring of the ground vehicle and the non-linearity of the GMTI measurement model. Unlike the commonly used algorithms such as the interacting multiple model <span class="hlt">particle</span> <span class="hlt">filter</span> (IMMPF) and bootstrap multiple model <span class="hlt">particle</span> <span class="hlt">filter</span> (BS-MMPF), we propose a new algorithm integrating the more efficient auxiliary <span class="hlt">particle</span> <span class="hlt">filter</span> (APF) into a Bayesian framework. Moreover, since the movement of the ground vehicle is likely to be constrained by the road, this information is taken as the domain knowledge and applied together with the tracking algorithm for improving the tracking performance. Simulations are presented to show the advantages of both the new algorithm and incorporation of the road information by evaluating the root mean square error (RMSE).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110012253','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110012253"><span id="translatedtitle"><span class="hlt">Optimal</span> Tuner Selection for Kalman-<span class="hlt">Filter</span>-Based Aircraft Engine Performance Estimation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Simon, Donald L.; Garg, Sanjay</p> <p>2011-01-01</p> <p>An emerging approach in the field of aircraft engine controls and system health management is the inclusion of real-time, onboard models for the inflight estimation of engine performance variations. This technology, typically based on Kalman-<span class="hlt">filter</span> concepts, enables the estimation of unmeasured engine performance parameters that can be directly utilized by controls, prognostics, and health-management applications. A challenge that complicates this practice is the fact that an aircraft engine s performance is affected by its level of degradation, generally described in terms of unmeasurable health parameters such as efficiencies and flow capacities related to each major engine module. Through Kalman-<span class="hlt">filter</span>-based estimation techniques, the level of engine performance degradation can be estimated, given that there are at least as many sensors as health parameters to be estimated. However, in an aircraft engine, the number of sensors available is typically less than the number of health parameters, presenting an under-determined estimation problem. A common approach to address this shortcoming is to estimate a subset of the health parameters, referred to as model tuning parameters. The problem/objective is to <span class="hlt">optimally</span> select the model tuning parameters to minimize Kalman-filterbased estimation error. A tuner selection technique has been developed that specifically addresses the under-determined estimation problem, where there are more unknown parameters than available sensor measurements. A systematic approach is applied to produce a model tuning parameter vector of appropriate dimension to enable estimation by a Kalman <span class="hlt">filter</span>, while minimizing the estimation error in the parameters of interest. Tuning parameter selection is performed using a multi-variable iterative search routine that seeks to minimize the theoretical mean-squared estimation error of the Kalman <span class="hlt">filter</span>. This approach can significantly reduce the error in onboard aircraft engine parameter estimation applications such as model-based diagnostic, controls, and life usage calculations. The advantage of the innovation is the significant reduction in estimation errors that it can provide relative to the conventional approach of selecting a subset of health parameters to serve as the model tuning parameter vector. Because this technique needs only to be performed during the system design process, it places no additional computation burden on the onboard Kalman <span class="hlt">filter</span> implementation. The technique has been developed for aircraft engine onboard estimation applications, as this application typically presents an under-determined estimation problem. However, this generic technique could be applied to other industries using gas turbine engine technology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26999130','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26999130"><span id="translatedtitle"><span class="hlt">Particle</span> <span class="hlt">Filter</span> with Novel Nonlinear Error Model for Miniature Gyroscope-Based Measurement While Drilling Navigation.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Tao; Yuan, Gannan; Li, Wang</p> <p>2016-01-01</p> <p>The derivation of a conventional error model for the miniature gyroscope-based measurement while drilling (MGWD) system is based on the assumption that the errors of attitude are small enough so that the direction cosine matrix (DCM) can be approximated or simplified by the errors of small-angle attitude. However, the simplification of the DCM would introduce errors to the navigation solutions of the MGWD system if the initial alignment cannot provide precise attitude, especially for the low-cost microelectromechanical system (MEMS) sensors operated in harsh multilateral horizontal downhole drilling environments. This paper proposes a novel nonlinear error model (NNEM) by the introduction of the error of DCM, and the NNEM can reduce the propagated errors under large-angle attitude error conditions. The zero velocity and zero position are the reference points and the innovations in the states estimation of <span class="hlt">particle</span> <span class="hlt">filter</span> (PF) and Kalman <span class="hlt">filter</span> (KF). The experimental results illustrate that the performance of PF is better than KF and the PF with NNEM can effectively restrain the errors of system states, especially for the azimuth, velocity, and height in the quasi-stationary condition. PMID:26999130</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4813946','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4813946"><span id="translatedtitle"><span class="hlt">Particle</span> <span class="hlt">Filter</span> with Novel Nonlinear Error Model for Miniature Gyroscope-Based Measurement While Drilling Navigation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Li, Tao; Yuan, Gannan; Li, Wang</p> <p>2016-01-01</p> <p>The derivation of a conventional error model for the miniature gyroscope-based measurement while drilling (MGWD) system is based on the assumption that the errors of attitude are small enough so that the direction cosine matrix (DCM) can be approximated or simplified by the errors of small-angle attitude. However, the simplification of the DCM would introduce errors to the navigation solutions of the MGWD system if the initial alignment cannot provide precise attitude, especially for the low-cost microelectromechanical system (MEMS) sensors operated in harsh multilateral horizontal downhole drilling environments. This paper proposes a novel nonlinear error model (NNEM) by the introduction of the error of DCM, and the NNEM can reduce the propagated errors under large-angle attitude error conditions. The zero velocity and zero position are the reference points and the innovations in the states estimation of <span class="hlt">particle</span> <span class="hlt">filter</span> (PF) and Kalman <span class="hlt">filter</span> (KF). The experimental results illustrate that the performance of PF is better than KF and the PF with NNEM can effectively restrain the errors of system states, especially for the azimuth, velocity, and height in the quasi-stationary condition. PMID:26999130</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23464014','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23464014"><span id="translatedtitle"><span class="hlt">Particle</span> velocity estimation based on a two-microphone array and Kalman <span class="hlt">filter</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bai, Mingsian R; Juan, Shen-Wei; Chen, Ching-Cheng</p> <p>2013-03-01</p> <p>A traditional method to measure <span class="hlt">particle</span> velocity is based on the finite difference (FD) approximation of pressure gradient by using a pair of well matched pressure microphones. This approach is known to be sensitive to sensor noise and mismatch. Recently, a double hot-wire sensor termed Microflown became available in light of micro-electro-mechanical system technology. This sensor eliminates the robustness issue of the conventional FD-based methods. In this paper, an alternative two-microphone approach termed the u-sensor is developed from the perspective of robust adaptive <span class="hlt">filtering</span>. With two ordinary microphones, the proposed u-sensor does not require novel fabrication technology. In the method, plane wave and spherical wave models are employed in the formulation of a Kalman <span class="hlt">filter</span> with process and measurement noise taken into account. Both numerical and experimental investigations were undertaken to validate the proposed u-sensor technique. The results have shown that the proposed approach attained better performance than the FD method, and comparable performance to a Microflown sensor. PMID:23464014</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SPIE.7495E..2FC','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SPIE.7495E..2FC"><span id="translatedtitle"><span class="hlt">Particle-filter</span>-based object tracking with color and texture information fusion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, RuiQing; Zhang, ZhaoHui; Lu, HanQing; Cui, HuiQing; Yan, YuKun</p> <p>2009-10-01</p> <p>In this paper, we investigate object tracking in video sequences and propose a <span class="hlt">particle</span> <span class="hlt">filter</span> based tracking algorithm with color and texture information fusion, in which the target model is jointly represented by spatial-weighted color histogram and LBP (Local Binary Patterns) texture histogram. The property of local grayscale or color invariance for LBP operator makes it more reliable to measure the spatial structure of local image texture. The system is less sensitive to illumination changes and partial occlusions, and can be able to track objects in diverse conditions. Experimental results demonstrate that the performance of the proposed method is more robust and accurate than the original color based method, especially when tracking objects with similar color appearance to the background and partial occlusions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4481977','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4481977"><span id="translatedtitle">Mobile Robot Positioning with 433-MHz Wireless Motes with Varying Transmission Powers and a <span class="hlt">Particle</span> <span class="hlt">Filter</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Canedo-Rodriguez, Adrian; Rodriguez, Jose Manuel; Alvarez-Santos, Victor; Iglesias, Roberto; Regueiro, Carlos V.</p> <p>2015-01-01</p> <p>In wireless positioning systems, the transmitter's power is usually fixed. In this paper, we explore the use of varying transmission powers to increase the performance of a wireless localization system. To this extent, we have designed a robot positioning system based on wireless motes. Our motes use an inexpensive, low-power sub-1-GHz system-on-chip (CC1110) working in the 433-MHz ISM band. Our localization algorithm is based on a <span class="hlt">particle</span> <span class="hlt">filter</span> and infers the robot position by: (1) comparing the power received with the expected one; and (2) integrating the robot displacement. We demonstrate that the use of transmitters that vary their transmission power over time improves the performance of the wireless positioning system significantly, with respect to a system that uses fixed power transmitters. This opens the door for applications where the robot can localize itself actively by requesting the transmitters to change their power in real time. PMID:25942641</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EJASP2009....7P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EJASP2009....7P"><span id="translatedtitle">Video Tracking Using Dual-Tree Wavelet Polar Matching and Rao-Blackwellised <span class="hlt">Particle</span> <span class="hlt">Filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pang, Sze Kim; Nelson, James D. B.; Godsill, Simon J.; Kingsbury, Nick</p> <p>2010-12-01</p> <p>We describe a video tracking application using the dual-tree Polar Matching Algorithm. We develop the dynamical and observation models in a probabilistic setting and study the empirical probability distribution of the Polar Matching output. We model the visible and occluded target statistics using Beta distributions. This is incorporated into a Track-Before-Detect (TBD) solution for the overall observation likelihood of each video frame and provides a principled derivation of the observation likelihood. Due to the nonlinear nature of the problem, we design a Rao-Blackwellised <span class="hlt">Particle</span> <span class="hlt">Filter</span> (RBPF) for the sequential inference. Computer simulations demonstrate the ability of the algorithm to track a simulated video moving target in an urban environment with complete and partial occlusions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015OptRv..22..294J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015OptRv..22..294J"><span id="translatedtitle">Indoor anti-occlusion visible light positioning systems based on <span class="hlt">particle</span> <span class="hlt">filtering</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jiang, Meng; Huang, Zhitong; Li, Jianfeng; Zhang, Ruqi; Ji, Yuefeng</p> <p>2015-04-01</p> <p>As one of the most popular categories of mobile services, a rapid growth of indoor location-based services has been witnessed over the past decades. Indoor positioning methods based on Wi-Fi, radio-frequency identification or Bluetooth are widely commercialized; however, they have disadvantages such as low accuracy or high cost. An emerging method using visible light is under research recently. The existed visible light positioning (VLP) schemes using carrier allocation, time allocation and multiple receivers all have limitations. This paper presents a novel mechanism using <span class="hlt">particle</span> <span class="hlt">filtering</span> in VLP system. By this method no additional devices are needed and the occlusion problem in visible light would be alleviated which will effectively enhance the flexibility for indoor positioning.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JIEIC..96...49M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JIEIC..96...49M"><span id="translatedtitle">An Accelerated <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> Algorithm on Parametric <span class="hlt">Optimization</span> of WEDM of Die-Steel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Muthukumar, V.; Suresh Babu, A.; Venkatasamy, R.; Senthil Kumar, N.</p> <p>2015-01-01</p> <p>This study employed Accelerated <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (APSO) algorithm to <span class="hlt">optimize</span> the machining parameters that lead to a maximum Material Removal Rate (MRR), minimum surface roughness and minimum kerf width values for Wire Electrical Discharge Machining (WEDM) of AISI D3 die-steel. Four machining parameters that are <span class="hlt">optimized</span> using APSO algorithm include Pulse on-time, Pulse off-time, Gap voltage, Wire feed. The machining parameters are evaluated by Taguchi's L9 Orthogonal Array (OA). Experiments are conducted on a CNC WEDM and output responses such as material removal rate, surface roughness and kerf width are determined. The empirical relationship between control factors and output responses are established by using linear regression models using Minitab software. Finally, APSO algorithm, a nature inspired metaheuristic technique, is used to <span class="hlt">optimize</span> the WEDM machining parameters for higher material removal rate and lower kerf width with surface roughness as constraint. The confirmation experiments carried out with the optimum conditions show that the proposed algorithm was found to be potential in finding numerous <span class="hlt">optimal</span> input machining parameters which can fulfill wide requirements of a process engineer working in WEDM industry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ITEIS.131..461M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ITEIS.131..461M"><span id="translatedtitle"><span class="hlt">Optimal</span> Price Decision Problem for Simultaneous Multi-article Auction and Its <span class="hlt">Optimal</span> Price Searching Method by <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Masuda, Kazuaki; Aiyoshi, Eitaro</p> <p></p> <p>We propose a method for solving <span class="hlt">optimal</span> price decision problems for simultaneous multi-article auctions. An auction problem, originally formulated as a combinatorial problem, determines both every seller's whether or not to sell his/her article and every buyer's which article(s) to buy, so that the total utility of buyers and sellers will be maximized. Due to the duality theory, we transform it equivalently into a dual problem in which Lagrange multipliers are interpreted as articles' transaction price. As the dual problem is a continuous <span class="hlt">optimization</span> problem with respect to the multipliers (i.e., the transaction prices), we propose a numerical method to solve it by applying heuristic global search methods. In this paper, <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) is used to solve the dual problem, and experimental results are presented to show the validity of the proposed method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25675449','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25675449"><span id="translatedtitle">Graphics-processor-unit-based parallelization of <span class="hlt">optimized</span> baseline wander <span class="hlt">filtering</span> algorithms for long-term electrocardiography.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Niederhauser, Thomas; Wyss-Balmer, Thomas; Haeberlin, Andreas; Marisa, Thanks; Wildhaber, Reto A; Goette, Josef; Jacomet, Marcel; Vogel, Rolf</p> <p>2015-06-01</p> <p>Long-term electrocardiogram (ECG) often suffers from relevant noise. Baseline wander in particular is pronounced in ECG recordings using dry or esophageal electrodes, which are dedicated for prolonged registration. While analog high-pass <span class="hlt">filters</span> introduce phase distortions, reliable offline <span class="hlt">filtering</span> of the baseline wander implies a computational burden that has to be put in relation to the increase in signal-to-baseline ratio (SBR). Here, we present a graphics processor unit (GPU)-based parallelization method to speed up offline baseline wander <span class="hlt">filter</span> algorithms, namely the wavelet, finite, and infinite impulse response, moving mean, and moving median <span class="hlt">filter</span>. Individual <span class="hlt">filter</span> parameters were <span class="hlt">optimized</span> with respect to the SBR increase based on ECGs from the Physionet database superimposed to autoregressive modeled, real baseline wander. A Monte-Carlo simulation showed that for low input SBR the moving median <span class="hlt">filter</span> outperforms any other method but negatively affects ECG wave detection. In contrast, the infinite impulse response <span class="hlt">filter</span> is preferred in case of high input SBR. However, the parallelized wavelet <span class="hlt">filter</span> is processed 500 and four times faster than these two algorithms on the GPU, respectively, and offers superior baseline wander suppression in low SBR situations. Using a signal segment of 64 mega samples that is <span class="hlt">filtered</span> as entire unit, wavelet <span class="hlt">filtering</span> of a seven-day high-resolution ECG is computed within less than 3 s. Taking the high <span class="hlt">filtering</span> speed into account, the GPU wavelet <span class="hlt">filter</span> is the most efficient method to remove baseline wander present in long-term ECGs, with which computational burden can be strongly reduced. PMID:25675449</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AIPC.1168..240S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AIPC.1168..240S"><span id="translatedtitle"><span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> Approach in a Consignment Inventory System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sharifyazdi, Mehdi; Jafari, Azizollah; Molamohamadi, Zohreh; Rezaeiahari, Mandana; Arshizadeh, Rahman</p> <p>2009-09-01</p> <p>Consignment Inventory (CI) is a kind of inventory which is in the possession of the customer, but is still owned by the supplier. This creates a condition of shared risk whereby the supplier risks the capital investment associated with the inventory while the customer risks dedicating retail space to the product. This paper considers both the vendor's and the retailers' costs in an integrated model. The vendor here is a warehouse which stores one type of product and supplies it at the same wholesale price to multiple retailers who then sell the product in independent markets at retail prices. Our main aim is to design a CI system which generates minimum costs for the two parties. Here a <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) algorithm is developed to calculate the proper values. Finally a sensitivity analysis is performed to examine the effects of each parameter on decision variables. Also PSO performance is compared with genetic algorithm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4658170','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4658170"><span id="translatedtitle">Reliably Detecting Clinically Important Variants Requires Both Combined Variant Calls and <span class="hlt">Optimized</span> <span class="hlt">Filtering</span> Strategies</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Field, Matthew A.; Cho, Vicky</p> <p>2015-01-01</p> <p>A diversity of tools is available for identification of variants from genome sequence data. Given the current complexity of incorporating external software into a genome analysis infrastructure, a tendency exists to rely on the results from a single tool alone. The quality of the output variant calls is highly variable however, depending on factors such as sequence library quality as well as the choice of short-read aligner, variant caller, and variant caller <span class="hlt">filtering</span> strategy. Here we present a two-part study first using the high quality ‘genome in a bottle’ reference set to demonstrate the significant impact the choice of aligner, variant caller, and variant caller <span class="hlt">filtering</span> strategy has on overall variant call quality and further how certain variant callers outperform others with increased sample contamination, an important consideration when analyzing sequenced cancer samples. This analysis confirms previous work showing that combining variant calls of multiple tools results in the best quality resultant variant set, for either specificity or sensitivity, depending on whether the intersection or union, of all variant calls is used respectively. Second, we analyze a melanoma cell line derived from a control lymphocyte sample to determine whether software choices affect the detection of clinically important melanoma risk-factor variants finding that only one of the three such variants is unanimously detected under all conditions. Finally, we describe a cogent strategy for implementing a clinical variant detection pipeline; a strategy that requires careful software selection, variant caller <span class="hlt">filtering</span> <span class="hlt">optimizing</span>, and combined variant calls in order to effectively minimize false negative variants. While implementing such features represents an increase in complexity and computation the results offer indisputable improvements in data quality. PMID:26600436</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8777E..1BE','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8777E..1BE"><span id="translatedtitle">Spectral <span class="hlt">filtering</span> <span class="hlt">optimization</span> of a measuring channel of an x-ray broadband spectrometer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Emprin, B.; Troussel, Ph.; Villette, B.; Delmotte, F.</p> <p>2013-05-01</p> <p>A new channel of an X-ray broadband spectrometer has been developed for the 2 - 4 keV spectral range. It uses a spectral <span class="hlt">filtering</span> by using a non-periodic multilayer mirror. This channel is composed by a <span class="hlt">filter</span>, an aperiodic multilayer mirror and a detector. The design and realization of the optical coating mirror has been defined such as the reflectivity is above 8% in almost the entire bandwidth range 2 - 4 keV and lower than 2% outside. The mirror is <span class="hlt">optimized</span> for working at 1.9° grazing incidence. The mirror is coated with a stack of 115 chromium / scandium (Cr / Sc) non-periodic layers, between 0.6 nm and 7.3 nm and a 3 nm thick top SiO2 layer to protect the stack from oxidization. To control thin thicknesses, we produced specific multilayer mirrors which consist on a superposition of two periodic Cr / Sc multilayers with the layer to calibrate in between. The mirror and subnanometric layers characterizations were made at the "Laboratoire Charles Fabry" (LCF) with a grazing incidence reflectometer working at 8.048 keV (Cu Kα radiation) and at the synchrotron radiation facility SOLEIL on the hard X-ray branch of the "Metrology" beamline. The reflectivity of the mirrors as a function of the photon energy was obtained in the Physikalisch Technische Bundesanstalt (PTB) laboratory at the synchrotron radiation facility Bessy II.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22917190','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22917190"><span id="translatedtitle">A modified statistically <span class="hlt">optimal</span> null <span class="hlt">filter</span> method for recognizing protein-coding regions.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Lei; Tian, Fengchun; Wang, Shiyuan</p> <p>2012-06-01</p> <p>Computer-aided protein-coding gene prediction in uncharacterized genomic DNA sequences is one of the most important issues of biological signal processing. A modified <span class="hlt">filter</span> method based on a statistically <span class="hlt">optimal</span> null <span class="hlt">filter</span> (SONF) theory is proposed for recognizing protein-coding regions. The square deviation gain (SDG) between the input and output of the model is used to identify the coding regions. The effective SDG amplification model with Class I and Class II enhancement is designed to suppress the non-coding regions. Also, an evaluation algorithm has been used to compare the modified model with most gene prediction methods currently available in terms of sensitivity, specificity and precision. The performance for identification of protein-coding regions has been evaluated at the nucleotide level using benchmark datasets and 91.4%, 96%, 93.7% were obtained for sensitivity, specificity and precision, respectively. These results suggest that the proposed model is potentially useful in gene finding field, which can help recognize protein-coding regions with higher precision and speed than present algorithms. PMID:22917190</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JaJAP..54hKA05T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JaJAP..54hKA05T"><span id="translatedtitle"><span class="hlt">Optimal</span> design of bandpass <span class="hlt">filters</span> to reduce emission from photovoltaic cells under monochromatic illumination</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Takeda, Yasuhiko; Iizuka, Hideo; Ito, Tadashi; Mizuno, Shintaro; Hasegawa, Kazuo; Ichikawa, Tadashi; Ito, Hiroshi; Kajino, Tsutomu; Higuchi, Kazuo; Ichiki, Akihisa; Motohiro, Tomoyoshi</p> <p>2015-08-01</p> <p>We have theoretically investigated photovoltaic cells used under the illumination condition of monochromatic light incident from a particular direction, which is very different from that for solar cells under natural sunlight, using detailed balance modeling. A multilayer bandpass <span class="hlt">filter</span> formed on the surface of the cell has been found to trap the light generated by radiative recombination inside the cell, reduce emission from the cell, and consequently improve conversion efficiency. The light trapping mechanism is interpreted in terms of a one-dimensional photonic crystal, and the design guide to <span class="hlt">optimize</span> the multilayer structure has been clarified. For obliquely incident illumination, as well as normal incidence, a significant light trapping effect has been achieved, although the emission patterns are extremely different from each other depending on the incident directions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015OptCo.349...31S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015OptCo.349...31S"><span id="translatedtitle">An <span class="hlt">optimized</span> strain demodulation method for PZT driven fiber Fabry-Perot tunable <span class="hlt">filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sheng, Wenjuan; Peng, G. D.; Liu, Yang; Yang, Ning</p> <p>2015-08-01</p> <p>An <span class="hlt">optimized</span> strain-demodulation-method based on piezo-electrical transducer (PZT) driven fiber Fabry-Perot (FFP) <span class="hlt">filter</span> is proposed and experimentally demonstrated. Using a parallel processing mode to drive the PZT continuously, the hysteresis effect is eliminated, and the system demodulation rate is increased. Furthermore, an AC-DC compensation method is developed to address the intrinsic nonlinear relationship between the displacement and voltage of PZT. The experimental results show that the actual demodulation rate is improved from 15 Hz to 30 Hz, the random error of the strain measurement is decreased by 95%, and the deviation between the test values after compensation and the theoretical values is less than 1 pm/??.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012MSSP...28..597C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012MSSP...28..597C"><span id="translatedtitle">Machine remaining useful life prediction: An integrated adaptive neuro-fuzzy and high-order <span class="hlt">particle</span> <span class="hlt">filtering</span> approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Chaochao; Vachtsevanos, George; Orchard, Marcos E.</p> <p>2012-04-01</p> <p>Machine prognosis can be considered as the generation of long-term predictions that describe the evolution in time of a fault indicator, with the purpose of estimating the remaining useful life (RUL) of a failing component/subsystem so that timely maintenance can be performed to avoid catastrophic failures. This paper proposes an integrated RUL prediction method using adaptive neuro-fuzzy inference systems (ANFIS) and high-order <span class="hlt">particle</span> <span class="hlt">filtering</span>, which forecasts the time evolution of the fault indicator and estimates the probability density function (pdf) of RUL. The ANFIS is trained and integrated in a high-order <span class="hlt">particle</span> <span class="hlt">filter</span> as a model describing the fault progression. The high-order <span class="hlt">particle</span> <span class="hlt">filter</span> is used to estimate the current state and carry out p-step-ahead predictions via a set of <span class="hlt">particles</span>. These predictions are used to estimate the RUL pdf. The performance of the proposed method is evaluated via the real-world data from a seeded fault test for a UH-60 helicopter planetary gear plate. The results demonstrate that it outperforms both the conventional ANFIS predictor and the <span class="hlt">particle-filter</span>-based predictor where the fault growth model is a first-order model that is trained via the ANFIS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3064684','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3064684"><span id="translatedtitle"><span class="hlt">Optimizing</span> magnetite nanoparticles for mass sensitivity in magnetic <span class="hlt">particle</span> imaging</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ferguson, R. Matthew; Minard, Kevin R.; Khandhar, Amit P.; Krishnan, Kannan M.</p> <p>2011-01-01</p> <p>Purpose: Magnetic <span class="hlt">particle</span> imaging (MPI), using magnetite nanoparticles (MNPs) as tracer material, shows great promise as a platform for fast tomographic imaging. To date, the magnetic properties of MNPs used in imaging have not been <span class="hlt">optimized</span>. As nanoparticle magnetism shows strong size dependence, the authors explore how varying MNP size impacts imaging performance in order to determine <span class="hlt">optimal</span> MNP characteristics for MPI at any driving field frequency f0. Methods: Monodisperse MNPs of varying size were synthesized and their magnetic properties characterized. Their MPI response was measured experimentally using a custom-built MPI transceiver designed to detect the third harmonic of MNP magnetization. The driving field amplitude H0=6 mT μ0−1 and frequency f0=250 kHz were chosen to be suitable for imaging small animals. Experimental results were interpreted using a model of dynamic MNP magnetization that is based on the Langevin theory of superparamagnetism and accounts for sample size distribution and size-dependent magnetic relaxation. Results: The experimental results show a clear variation in the MPI signal intensity as a function of MNP diameter that is in agreement with simulated results. A maximum in the plot of MPI signal vs MNP size indicates there is a particular size that is <span class="hlt">optimal</span> for the chosen f0. Conclusions: The authors observed that MNPs 15 nm in diameter generate maximum signal amplitude in MPI experiments at 250 kHz. The authors expect the physical basis for this result, the change in magnetic relaxation with MNP size, will impact MPI under other experimental conditions. PMID:21520874</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23339437','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23339437"><span id="translatedtitle">Penetration of fiber versus spherical <span class="hlt">particles</span> through <span class="hlt">filter</span> media and faceseal leakage of N95 <span class="hlt">filtering</span> facepiece respirators with cyclic flow.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cho, Kyungmin Jacob; Turkevich, Leonid; Miller, Matthew; McKay, Roy; Grinshpun, Sergey A; Ha, KwonChul; Reponen, Tiina</p> <p>2013-01-01</p> <p>This study investigated differences in penetration between fibers and spherical <span class="hlt">particles</span> through faceseal leakage of an N95 <span class="hlt">filtering</span> facepiece respirator. Three cyclic breathing flows were generated corresponding to mean inspiratory flow rates (MIF) of 15, 30, and 85 L/min. Fibers had a mean diameter of 1 μm and a median length of 4.9 μm (calculated aerodynamic diameter, d(ae) = 1.73 μm). Monodisperse polystyrene spheres with a mean physical diameter of 1.01 μm (PSI) and 1.54 μm (PSII) were used for comparison (calculated d(ae) = 1.05 and 1.58 μm, respectively). Two optical <span class="hlt">particle</span> counters simultaneously determined concentrations inside and outside the respirator. Geometric means (GMs) for <span class="hlt">filter</span> penetration of the fibers were 0.06, 0.09, and 0.08% at MIF of 15, 30, and 85 L/min, respectively. Corresponding values for PSI were 0.07, 0.12, and 0.12%. GMs for faceseal penetration of fibers were 0.40, 0.14, and 0.09% at MIF of 15, 30, and 85 L/min, respectively. Corresponding values for PSI were 0.96, 0.41, and 0.17%. Faceseal penetration decreased with increased breathing rate for both types of <span class="hlt">particles</span> (p ≤ 0.001). GMs of <span class="hlt">filter</span> and faceseal penetration of PSII at an MIF of 30 L/min were 0.14% and 0.36%, respectively. <span class="hlt">Filter</span> penetration and faceseal penetration of fibers were significantly lower than those of PSI (p < 0.001) and PSII (p < 0.003). This confirmed that higher penetration of PSI was not due to slightly smaller aerodynamic diameter, indicating that the shape of fibers rather than their calculated mean aerodynamic diameter is a prevailing factor on deposition mechanisms through the tested respirator. In conclusion, faceseal penetration of fibers and spherical <span class="hlt">particles</span> decreased with increasing breathing rate, which can be explained by increased capture by impaction. Spherical <span class="hlt">particles</span> had 2.0-2.8 times higher penetration through faceseal leaks and 1.1-1.5 higher penetration through <span class="hlt">filter</span> media than fibers, which can be attributed to differences in interception losses. PMID:23339437</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AtmEn..44..909T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AtmEn..44..909T"><span id="translatedtitle">Diesel passenger car PM emissions: From Euro 1 to Euro 4 with <span class="hlt">particle</span> <span class="hlt">filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tzamkiozis, Theodoros; Ntziachristos, Leonidas; Samaras, Zissis</p> <p>2010-03-01</p> <p>This paper examines the impact of the emission control and fuel technology development on the emissions of gaseous and, in particular, PM pollutants from diesel passenger cars. Three cars in five configurations in total were measured, and covered the range from Euro 1 to Euro 4 standards. The emission control ranged from no aftertreatment in the Euro 1 case, an oxidation catalyst in Euro 2, two oxidation catalysts and exhaust gas recirculation in Euro 3 and Euro 4, while a catalyzed diesel <span class="hlt">particle</span> <span class="hlt">filter</span> (DPF) fitted in the Euro 4 car led to a Euro 4 + DPF configuration. Both certification test and real-world driving cycles were employed. The results showed that CO and HC emissions were much lower than the emission standard over the hot-start real-world cycles. However, vehicle technologies from Euro 2 to Euro 4 exceeded the NOx and PM emission levels over at least one real-world cycle. The NOx emission level reached up to 3.6 times the certification level in case of the Euro 4 car. PM were up to 40% and 60% higher than certification level for the Euro 2 and Euro 3 cars, while the Euro 4 car emitted close or slightly below the certification level over the real-world driving cycles. PM mass reductions from Euro 1 to Euro 4 were associated with a relevant decrease in the total <span class="hlt">particle</span> number, in particular over the certification test. This was not followed by a respective reduction in the solid <span class="hlt">particle</span> number which remained rather constant between the four technologies at 0.86 × 10 14 km -1 (coefficient of variation 9%). As a result, the ratio of solid vs. total <span class="hlt">particle</span> number ranged from ˜50% in Euro 1-100% in Euro 4. A significant reduction of more than three orders of magnitude in solid <span class="hlt">particle</span> number is achieved with the introduction of the DPF. However, the potential for nucleation mode formation at high speed from the DPF car is an issue that needs to be considered in the over all assessment of its environmental benefit. Finally, comparison of the mobility and aerodynamic diameters of airborne <span class="hlt">particles</span> led to fractal dimensions dropping from 2.60 (Euro 1) to 2.51 (Euro 4), denoting a more loose structure with improving technology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......437M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......437M"><span id="translatedtitle">Microwave-based medical diagnosis using <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> algorithm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Modiri, Arezoo</p> <p></p> <p>This dissertation proposes and investigates a novel architecture intended for microwave-based medical diagnosis (MBMD). Furthermore, this investigation proposes novel modifications of <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> algorithm for achieving enhanced convergence performance. MBMD has been investigated through a variety of innovative techniques in the literature since the 1990's and has shown significant promise in early detection of some specific health threats. In comparison to the X-ray- and gamma-ray-based diagnostic tools, MBMD does not expose patients to ionizing radiation; and due to the maturity of microwave technology, it lends itself to miniaturization of the supporting systems. This modality has been shown to be effective in detecting breast malignancy, and hence, this study focuses on the same modality. A novel radiator device and detection technique is proposed and investigated in this dissertation. As expected, hardware design and implementation are of paramount importance in such a study, and a good deal of research, analysis, and evaluation has been done in this regard which will be reported in ensuing chapters of this dissertation. It is noteworthy that an important element of any detection system is the algorithm used for extracting signatures. Herein, the strong intrinsic potential of the swarm-intelligence-based algorithms in solving complicated electromagnetic problems is brought to bear. This task is accomplished through addressing both mathematical and electromagnetic problems. These problems are called benchmark problems throughout this dissertation, since they have known answers. After evaluating the performance of the algorithm for the chosen benchmark problems, the algorithm is applied to MBMD tumor detection problem. The chosen benchmark problems have already been tackled by solution techniques other than <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO) algorithm, the results of which can be found in the literature. However, due to the relatively high level of complexity and randomness inherent to the selection of electromagnetic benchmark problems, a trend to resort to oversimplification in order to arrive at reasonable solutions has been taken in literature when utilizing analytical techniques. Here, an attempt has been made to avoid oversimplification when using the proposed swarm-based <span class="hlt">optimization</span> algorithms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013OptEn..52k3105K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013OptEn..52k3105K"><span id="translatedtitle">Human tracking in thermal images using adaptive <span class="hlt">particle</span> <span class="hlt">filters</span> with online random forest learning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ko, Byoung Chul; Kwak, Joon-Young; Nam, Jae-Yeal</p> <p>2013-11-01</p> <p>This paper presents a fast and robust human tracking method to use in a moving long-wave infrared thermal camera under poor illumination with the existence of shadows and cluttered backgrounds. To improve the human tracking performance while minimizing the computation time, this study proposes an online learning of classifiers based on <span class="hlt">particle</span> <span class="hlt">filters</span> and combination of a local intensity distribution (LID) with oriented center-symmetric local binary patterns (OCS-LBP). Specifically, we design a real-time random forest (RF), which is the ensemble of decision trees for confidence estimation, and confidences of the RF are converted into a likelihood function of the target state. First, the target model is selected by the user and <span class="hlt">particles</span> are sampled. Then, RFs are generated using the positive and negative examples with LID and OCS-LBP features by online learning. The learned RF classifiers are used to detect the most likely target position in the subsequent frame in the next stage. Then, the RFs are learned again by means of fast retraining with the tracked object and background appearance in the new frame. The proposed algorithm is successfully applied to various thermal videos as tests and its tracking performance is better than those of other methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008SPIE.6813E..04W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008SPIE.6813E..04W"><span id="translatedtitle">Video object tracking using improved chamfer matching and condensation <span class="hlt">particle</span> <span class="hlt">filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Tao; Ding, Xiaoqing; Wang, Shengjin; Wang, Kongqiao</p> <p>2008-02-01</p> <p>Object tracking is an essential problem in the field of video and image processing. Although tracking algorithms working on gray video are convenient in actual applications, they are more difficult to be developed than those using color features, since less information is taken into account. Few researches have been dedicated to tracking object using edge information. In this paper, we proposed a novel video tracking algorithm based on edge information for gray videos. This method adopts the combination of a condensation <span class="hlt">particle</span> <span class="hlt">filter</span> and an improved chamfer matching. The improved chamfer matching is rotation invariant and capable of estimating the shift between an observed image patch and a template by an orientation distance transform. A modified discriminative likelihood measurement method that focuses on the difference is adopted. These values are normalized and used as the weights of <span class="hlt">particles</span> which predict and track the object. Experiment results show that our modifications to chamfer matching improve its performance in video tracking problem. And the algorithm is stable, robust, and can effectively handle rotation distortion. Further work can be done on updating the template to adapt to significant viewpoint and scale changes of the appearance of the object during the tracking process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8301E..0WR','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8301E..0WR"><span id="translatedtitle">Object tracking with adaptive HOG detector and adaptive Rao-Blackwellised <span class="hlt">particle</span> <span class="hlt">filter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rosa, Stefano; Paleari, Marco; Ariano, Paolo; Bona, Basilio</p> <p>2012-01-01</p> <p>Scenarios for a manned mission to the Moon or Mars call for astronaut teams to be accompanied by semiautonomous robots. A prerequisite for human-robot interaction is the capability of successfully tracking humans and objects in the environment. In this paper we present a system for real-time visual object tracking in 2D images for mobile robotic systems. The proposed algorithm is able to specialize to individual objects and to adapt to substantial changes in illumination and object appearance during tracking. The algorithm is composed by two main blocks: a detector based on Histogram of Oriented Gradient (HOG) descriptors and linear Support Vector Machines (SVM), and a tracker which is implemented by an adaptive Rao-Blackwellised <span class="hlt">particle</span> <span class="hlt">filter</span> (RBPF). The SVM is re-trained online on new samples taken from previous predicted positions. We use the effective sample size to decide when the classifier needs to be re-trained. Position hypotheses for the tracked object are the result of a clustering procedure applied on the set of <span class="hlt">particles</span>. The algorithm has been tested on challenging video sequences presenting strong changes in object appearance, illumination, and occlusion. Experimental tests show that the presented method is able to achieve near real-time performances with a precision of about 7 pixels on standard video sequences of dimensions 320 × 240.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011OptEn..50i7203H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011OptEn..50i7203H"><span id="translatedtitle">Tracking of mitochondrial transports using a <span class="hlt">particle</span> <span class="hlt">filtering</span> method with a spatial constraint</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hong, Sungmin; Shim, Hackjoon; Chung, Yoojin</p> <p>2011-09-01</p> <p>This paper describes a tracking method to trace the movements of fluorescently labeled mitochondria in time-lapse image sequences. It is based on <span class="hlt">particle</span> <span class="hlt">filtering</span>, which is a state-of-the-art tracking method, and is enhanced with a spatial constraint to improve robustness. Since mitochondria move only through axons, the spatial constraint is generated by axon segmentation on a single frame, which is the average of all the frames. The spatial constraint limits the search space of the state vector and, consequently, lowers the chance for the tracking to get lost. Using a background subtraction algorithm, the proposed method is also equipped with automatic detection of starting points, thus minimizing the requirement for user input. Implementation of the proposed method for tracking of fluorescently labeled mitochondria in time-lapse images showed substantially improved robustness and speed compared to a conventional method. With these improvements, this new <span class="hlt">particle</span> tracking method is expected to increase the throughput of fluorescently labeled mitochondrial transport experiments, which are required for neuroscience research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/10817828','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/10817828"><span id="translatedtitle"><span class="hlt">Filter</span>-feeding and cruising swimming speeds of basking sharks compared with <span class="hlt">optimal</span> models: they <span class="hlt">filter</span>-feed slower than predicted for their size.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sims</p> <p>2000-06-01</p> <p>Movements of six basking sharks (4.0-6.5 m total body length, L(T)) swimming at the surface were tracked and horizontal velocities determined. Sharks were tracked for between 1.8 and 55 min with between 4 and 21 mean speed determinations per shark track. The mean <span class="hlt">filter</span>-feeding swimming speed was 0.85 m s(-1) (+/-0.05 S.E., n=49 determinations) compared to the non-feeding (cruising) mean speed of 1.08 m s(-1) (+/-0.03 S.E., n=21 determinations). Both absolute (m s(-1)) and specific (L s(-1)) swimming speeds during <span class="hlt">filter</span>-feeding were significantly lower than when cruise swimming with the mouth closed, indicating basking sharks select speeds approximately 24% lower when engaged in <span class="hlt">filter</span>-feeding. This reduction in speed during <span class="hlt">filter</span>-feeding could be a behavioural response to avoid increased drag-induced energy costs associated with feeding at higher speeds. Non-feeding basking sharks (4 m L(T)) cruised at speeds close to, but slightly faster ( approximately 18%) than the optimum speed predicted by the Weihs (1977) [Weihs, D., 1977. Effects of size on the sustained swimming speeds of aquatic organisms. In: Pedley, T.J. (Ed.), Scale Effects in Animal Locomotion. Academic Press, London, pp. 333-338.] <span class="hlt">optimal</span> cruising speed model. In contrast, <span class="hlt">filter</span>-feeding basking sharks swam between 29 and 39% slower than the speed predicted by the Weihs and Webb (1983) [Weihs, D., Webb, P.W., 1983. <span class="hlt">Optimization</span> of locomotion. In: Webb, P.W., Weihs, D. (Eds.), Fish Biomechanics. Praeger, New York, pp. 339-371.] <span class="hlt">optimal</span> <span class="hlt">filter</span>-feeding model. This significant under-estimation in observed feeding speed compared to model predictions was most likely accounted for by surface drag effects reducing optimum speeds of tracked sharks, together with inaccurate parameter estimates used in the general model to predict <span class="hlt">optimal</span> speeds of basking sharks from body size extrapolations. PMID:10817828</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3934314','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3934314"><span id="translatedtitle">An Adaptive Hybrid Algorithm Based on <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> and Differential Evolution for Global <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yu, Xiaobing; Cao, Jie; Shan, Haiyan; Zhu, Li; Guo, Jun</p> <p>2014-01-01</p> <p><span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> (PSO) and differential evolution (DE) are both efficient and powerful population-based stochastic search techniques for solving <span class="hlt">optimization</span> problems, which have been widely applied in many scientific and engineering fields. Unfortunately, both of them can easily fly into local optima and lack the ability of jumping out of local optima. A novel adaptive hybrid algorithm based on PSO and DE (HPSO-DE) is formulated by developing a balanced parameter between PSO and DE. Adaptive mutation is carried out on current population when the population clusters around local optima. The HPSO-DE enjoys the advantages of PSO and DE and maintains diversity of the population. Compared with PSO, DE, and their variants, the performance of HPSO-DE is competitive. The balanced parameter sensitivity is discussed in detail. PMID:24688370</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JIEIB..95..231K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JIEIB..95..231K"><span id="translatedtitle">Reliability <span class="hlt">Optimization</span> of Radial Distribution Systems Employing Differential Evolution and Bare Bones <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kela, K. B.; Arya, L. D.</p> <p>2014-09-01</p> <p>This paper describes a methodology for determination of optimum failure rate and repair time for each section of a radial distribution system. An objective function in terms of reliability indices and their target values is selected. These indices depend mainly on failure rate and repair time of a section present in a distribution network. A cost is associated with the modification of failure rate and repair time. Hence the objective function is <span class="hlt">optimized</span> subject to failure rate and repair time of each section of the distribution network considering the total budget allocated to achieve the task. The problem has been solved using differential evolution and bare bones <span class="hlt">particle</span> swarm <span class="hlt">optimization</span>. The algorithm has been implemented on a sample radial distribution system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008SPIE.7140E..2ZU','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008SPIE.7140E..2ZU"><span id="translatedtitle">The first on-site evaluation of a new <span class="hlt">filter</span> <span class="hlt">optimized</span> for TARC and developer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Umeda, Toru; Ishibashi, Takeo; Nakamura, Atsushi; Ide, Junichi; Nagano, Masaru; Omura, Koichi; Tsuzuki, Shuichi; Numaguchi, Toru</p> <p>2008-11-01</p> <p>In previous studies, we identified <span class="hlt">filter</span> properties that have a strong effect on microbubble formation on the downstream side of the <span class="hlt">filter</span> membrane. A new Highly Asymmetric Polyarylsulfone (HAPAS) <span class="hlt">filter</span> was developed based on the findings. In the current study, we evaluated newly-developed HAPAS <span class="hlt">filter</span> in environmentally preferred non-PFOS TARC in a laboratory setting. Test results confirmed that microbubble counts downstream of the <span class="hlt">filter</span> were lower than those of a conventional HDPE <span class="hlt">filter</span>. Further testing in a manufacturing environment confirmed that HAPAS filtration of TARC at point of use was able to reduce defectivity caused by microbubbles on both unpatterned and patterned wafers, compared with a HDPE <span class="hlt">filter</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003PhDT........93T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003PhDT........93T"><span id="translatedtitle"><span class="hlt">Optimal</span> spatial <span class="hlt">filtering</span> for design of a conformal velocity sonar array</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Traweek, Charles M.</p> <p></p> <p>In stark contrast to the ubiquitous <span class="hlt">optimization</span> problem posed in the array processing literature, tactical hull sonar arrays have traditionally been designed using extrapolations of low spatial resolution empirical self noise data, dominated by hull noise at moderate speeds, in conjunction with assumptions regarding achievable conventional beamformer sidelobe levels by so-called Taylor shading for a time domain, delay-and-sum beamformer. That ad hoc process defaults to an extremely conservative (expensive and heavy) design for an array baffle as a means to assure environmental noise limited sonar performance. As an alternative, this dissertation formulates, implements, and demonstrates an objective function that results from the expression of the log likelihood ratio of the <span class="hlt">optimal</span> Bayesian detector as a comparison to a threshold. Its purpose is to maximize the deflection coefficient of a square-law energy detector over an arbitrarily specified frequency band by appropriate selection of array shading weights for the generalized conformal velocity sonar array under the assumption that it will employ the traditional time domain delay-and-sum beamformer. The restrictive assumptions that must be met in order to appropriately use the deflection coefficient as a performance metric are carefully delineated. A series of conformal velocity sonar array spatial <span class="hlt">filter</span> <span class="hlt">optimization</span> problems was defined using a data set characterized by spatially complex structural noise from a large aperture conformal velocity sonar array experiment. The detection performance of an 80-element cylindrical array was <span class="hlt">optimized</span> over a reasonably broad range of frequencies (from k0a = 12.95 to k 0a = 15.56) for the cases of broadside and off-broadside signal incidence. In each case, performance of the array using <span class="hlt">optimal</span> real-valued time domain delay-and-sum beamformer weights was much better than that achieved for either uniform shading or for Taylor shading. The result is an analytical engine with which to consider not only the tradeoff between <span class="hlt">optimality</span> and robustness in the definition of array baffle design requirements, but numerous other tradeoffs within the array design error budget allocation process as well.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AtmEn..37.5295H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AtmEn..37.5295H"><span id="translatedtitle">Effect of ventilation systems and air <span class="hlt">filters</span> on decay rates of <span class="hlt">particles</span> produced by indoor sources in an occupied townhouse</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Howard-Reed, Cynthia; Wallace, Lance A.; Emmerich, Steven J.</p> <p></p> <p>Several studies have shown the importance of <span class="hlt">particle</span> losses in real homes due to deposition and filtration; however, none have quantitatively shown the impact of using a central forced air fan and in-duct <span class="hlt">filter</span> on <span class="hlt">particle</span> loss rates. In an attempt to provide such data, we measured the deposition of <span class="hlt">particles</span> ranging from 0.3 to 10 μm in an occupied townhouse and also in an unoccupied test house. Experiments were run with three different sources (cooking with a gas stove, citronella candle, pouring kitty litter), with the central heating and air conditioning (HAC) fan on or off, and with two different types of in-duct <span class="hlt">filters</span> (electrostatic precipitator and ordinary furnace <span class="hlt">filter</span>). <span class="hlt">Particle</span> size, HAC fan operation, and the electrostatic precipitator had significant effects on <span class="hlt">particle</span> loss rates. The standard furnace <span class="hlt">filter</span> had no effect. Surprisingly, the type of source (combustion vs. mechanical generation) and the type of furnishings (fully furnished including carpet vs. largely unfurnished including mostly bare floor) also had no measurable effect on the deposition rates of <span class="hlt">particles</span> of comparable size. With the HAC fan off, average deposition rates varied from 0.3 h -1 for the smallest <span class="hlt">particle</span> range (0.3-0.5 μm) to 5.2 h -1 for <span class="hlt">particles</span> greater than 10 μm. Operation of the central HAC fan approximately doubled these rates for <span class="hlt">particles</span> <5 μm, and increased rates by 2 h -1 for the larger <span class="hlt">particles</span>. An in-duct electrostatic precipitator increased the loss rates compared to the fan-off condition by factors of 5-10 for <span class="hlt">particles</span> <2.5 μm, and by a factor of 3 for 2.5-5.0 μm <span class="hlt">particles</span>. In practical terms, use of the central fan alone could reduce indoor <span class="hlt">particle</span> concentrations by 25-50%, and use of an in-duct ESP could reduce <span class="hlt">particle</span> concentrations by 55-85% compared to fan-off conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040006352','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040006352"><span id="translatedtitle">An Explicit Linear <span class="hlt">Filtering</span> Solution for the <span class="hlt">Optimization</span> of Guidance Systems with Statistical Inputs</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stewart, Elwood C.</p> <p>1961-01-01</p> <p>The determination of optimum <span class="hlt">filtering</span> characteristics for guidance system design is generally a tedious process which cannot usually be carried out in general terms. In this report a simple explicit solution is given which is applicable to many different types of problems. It is shown to be applicable to problems which involve <span class="hlt">optimization</span> of constant-coefficient guidance systems and time-varying homing type systems for several stationary and nonstationary inputs. The solution is also applicable to off-design performance, that is, the evaluation of system performance for inputs for which the system was not specifically <span class="hlt">optimized</span>. The solution is given in generalized form in terms of the minimum theoretical error, the optimum transfer functions, and the optimum transient response. The effects of input signal, contaminating noise, and limitations on the response are included. From the results given, it is possible in an interception problem, for example, to rapidly assess the effects on minimum theoretical error of such factors as target noise and missile acceleration. It is also possible to answer important questions regarding the effect of type of target maneuver on optimum performance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=50576&keyword=refraction&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=71679909&CFTOKEN=61253857','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=50576&keyword=refraction&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=71679909&CFTOKEN=61253857"><span id="translatedtitle">PHOTOACOUSTIC DETERMINATION OF OPTICAL PROPERTIES OF AEROSOL <span class="hlt">PARTICLES</span> COLLECTED ON <span class="hlt">FILTERS</span>: DEVELOPMENT OF A METHOD TAKING INTO ACCOUNT SUBSTRATE REFLECTIVITY</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The absorptivity and imaginary index of refraction for carbon and methylene blue <span class="hlt">particles</span> were inferred from the photoacoustic spectra of samples collected on Teflon <span class="hlt">filter</span> substrates. Three models of varying complexity were developed to describe the photoacoustic signal as a fu...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AAS...21543809C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AAS...21543809C"><span id="translatedtitle">Fishing for Data: Using <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> to Search Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caputo, Daniel P.; Dolan, R.</p> <p>2010-01-01</p> <p>As the size of data and model sets continue to increase, more efficient ways are needed to sift through the available information. We present a computational method which will efficiently search large parameter spaces to either map the space or find individual data/models of interest. <span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> (PSO) is a subclass of artificial life computer algorithms. The PSO algorithm attempts to leverage "swarm intelligence” against finding <span class="hlt">optimal</span> solutions to a problem. This system is often based on a biological model of a swarm (e.g. schooling fish). These biological models are broken down into a few simple rules which govern the behavior of the system. "Agents” (e.g. fish) are introduced and the agents, following the rules, search out solutions much like a fish would seek out food. We have made extensive modifications to the standard PSO model which increase its efficiency as-well-as adding the capacity to map a parameter space and find multiple solutions. Our modified PSO is ideally suited to search and map large sets of data/models which are degenerate or to search through data/models which are too numerous to analyze by hand. One example of this would include radiative transfer models, which are inherently degenerate. Applying the PSO algorithm will allow the degeneracy space to be mapped and thus better determine limits on dust shell parameters. Another example is searching through legacy data from a survey for hints of Polycyclic Aromatic Hydrocarbon emission. What might have once taken years of searching (and many frustrated graduate students) can now be relegated to the task of a computer which will work day and night for only the cost of electricity. We hope this algorithm will allow fellow astronomers to more efficiently search data and models, thereby freeing them to focus on the physics of the Universe.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993SPIE.1772..201F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993SPIE.1772..201F"><span id="translatedtitle">Performance of mixed-metric <span class="hlt">optimized</span> ternary correlation <span class="hlt">filters</span> on realistic binary and gray-scale imagery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Flannery, David L.; Phillips, William E., III; Goldstein, Dennis H.</p> <p>1993-01-01</p> <p>The ternary phase-amplitude <span class="hlt">filter</span> (TPAF) is by definition restricted to the modulation values -1, 0, and 1, thus comprising a binary phase-only <span class="hlt">filter</span> (BPOF) multiplied by a binary- amplitude pattern, i.e., a region of support. The TPAF offers an attractive combination of real-time implementation with available devices and good correlation performance. Smart (<span class="hlt">optimized</span> distortion-invariant) TPAF formulations have been developed. The TPAF enables <span class="hlt">filter</span> implementation with magneto-optic devices and these devices also can be used for image input if gray scale scenes can be binarized while preserving good correlation performance. We provide simulation results addressing the comparative performance of mixed-metric smart TPAF's using gray scale, edge-enhanced and binary images derived from identical original scenes. The variation of <span class="hlt">filter</span> performance with training set background intensity level is examined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994OptEn..33.1767H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994OptEn..33.1767H"><span id="translatedtitle">Design and evaluation of three-level composite <span class="hlt">filters</span> obtained by <span class="hlt">optimizing</span> a compromise average performance measure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hendrix, Charles D.; Vijaya Kumar, B. V. K.</p> <p>1994-06-01</p> <p>Correlation <span class="hlt">filters</span> with three transmittance levels (+1, 0, and -1) are of interest in optical pattern recognition because they can be implemented on available spatial light modulators and because the zero level allows us to include a region of support (ROS). The ROS can provide additional control over the <span class="hlt">filter</span>'s noise tolerance and peak sharpness. A new algorithm based on <span class="hlt">optimizing</span> a compromise average performance measure (CAPM) is proposed for designing three-level composite <span class="hlt">filters</span>. The performance of this algorithm is compared to other three-level composite <span class="hlt">filter</span> designs using a common image database and using figures of merit such as the Fisher ratio, error rate, and light efficiency. It is shown that the CAPM algorithm yields better results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23144937','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23144937"><span id="translatedtitle">A Bayesian interpretation of the <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> and its kernel extension.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Andras, Peter</p> <p>2012-01-01</p> <p><span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> is a popular method for solving difficult <span class="hlt">optimization</span> problems. There have been attempts to formulate the method in formal probabilistic or stochastic terms (e.g. bare bones <span class="hlt">particle</span> swarm) with the aim to achieve more generality and explain the practical behavior of the method. Here we present a Bayesian interpretation of the <span class="hlt">particle</span> swarm <span class="hlt">optimization</span>. This interpretation provides a formal framework for incorporation of prior knowledge about the problem that is being solved. Furthermore, it also allows to extend the <span class="hlt">particle</span> <span class="hlt">optimization</span> method through the use of kernel functions that represent the intermediary transformation of the data into a different space where the <span class="hlt">optimization</span> problem is expected to be easier to be resolved-such transformation can be seen as a form of prior knowledge about the nature of the <span class="hlt">optimization</span> problem. We derive from the general Bayesian formulation the commonly used <span class="hlt">particle</span> swarm methods as particular cases. PMID:23144937</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22413537','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22413537"><span id="translatedtitle"><span class="hlt">Optimization</span> of leaf margins for lung stereotactic body radiotherapy using a flattening <span class="hlt">filter</span>-free beam</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wakai, Nobuhide; Sumida, Iori; Otani, Yuki; Suzuki, Osamu; Seo, Yuji; Isohashi, Fumiaki; Yoshioka, Yasuo; Ogawa, Kazuhiko; Hasegawa, Masatoshi</p> <p>2015-05-15</p> <p>Purpose: The authors sought to determine the <span class="hlt">optimal</span> collimator leaf margins which minimize normal tissue dose while achieving high conformity and to evaluate differences between the use of a flattening <span class="hlt">filter</span>-free (FFF) beam and a flattening-<span class="hlt">filtered</span> (FF) beam. Methods: Sixteen lung cancer patients scheduled for stereotactic body radiotherapy underwent treatment planning for a 7 MV FFF and a 6 MV FF beams to the planning target volume (PTV) with a range of leaf margins (−3 to 3 mm). Forty grays per four fractions were prescribed as a PTV D95. For PTV, the heterogeneity index (HI), conformity index, modified gradient index (GI), defined as the 50% isodose volume divided by target volume, maximum dose (Dmax), and mean dose (Dmean) were calculated. Mean lung dose (MLD), V20 Gy, and V5 Gy for the lung (defined as the volumes of lung receiving at least 20 and 5 Gy), mean heart dose, and Dmax to the spinal cord were measured as doses to organs at risk (OARs). Paired t-tests were used for statistical analysis. Results: HI was inversely related to changes in leaf margin. Conformity index and modified GI initially decreased as leaf margin width increased. After reaching a minimum, the two values then increased as leaf margin increased (“V” shape). The <span class="hlt">optimal</span> leaf margins for conformity index and modified GI were −1.1 ± 0.3 mm (mean ± 1 SD) and −0.2 ± 0.9 mm, respectively, for 7 MV FFF compared to −1.0 ± 0.4 and −0.3 ± 0.9 mm, respectively, for 6 MV FF. Dmax and Dmean for 7 MV FFF were higher than those for 6 MV FF by 3.6% and 1.7%, respectively. There was a positive correlation between the ratios of HI, Dmax, and Dmean for 7 MV FFF to those for 6 MV FF and PTV size (R = 0.767, 0.809, and 0.643, respectively). The differences in MLD, V20 Gy, and V5 Gy for lung between FFF and FF beams were negligible. The <span class="hlt">optimal</span> leaf margins for MLD, V20 Gy, and V5 Gy for lung were −0.9 ± 0.6, −1.1 ± 0.8, and −2.1 ± 1.2 mm, respectively, for 7 MV FFF compared to −0.9 ± 0.6, −1.1 ± 0.8, and −2.2 ± 1.3 mm, respectively, for 6 MV FF. With the heart inside the radiation field, the mean heart dose showed a V-shaped relationship with leaf margins. The <span class="hlt">optimal</span> leaf margins were −1.0 ± 0.6 mm for both beams. Dmax to the spinal cord showed no clear trend for changes in leaf margin. Conclusions: The differences in doses to OARs between FFF and FF beams were negligible. Conformity index, modified GI, MLD, lung V20 Gy, lung V5 Gy, and mean heart dose showed a V-shaped relationship with leaf margins. There were no significant differences in <span class="hlt">optimal</span> leaf margins to minimize these parameters between both FFF and FF beams. The authors’ results suggest that a leaf margin of −1 mm achieves high conformity and minimizes doses to OARs for both FFF and FF beams.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/790986','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/790986"><span id="translatedtitle"><span class="hlt">OPTIMIZATION</span> OF COAL <span class="hlt">PARTICLE</span> FLOW PATTERNS IN LOW NOX BURNERS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jost O.L. Wendt; Gregory E. Ogden; Jennifer Sinclair; Stephanus Budilarto</p> <p>2001-09-04</p> <p>It is well understood that the stability of axial diffusion flames is dependent on the mixing behavior of the fuel and combustion air streams. Combustion aerodynamic texts typically describe flame stability and transitions from laminar diffusion flames to fully developed turbulent flames as a function of increasing jet velocity. Turbulent diffusion flame stability is greatly influenced by recirculation eddies that transport hot combustion gases back to the burner nozzle. This recirculation enhances mixing and heats the incoming gas streams. Models describing these recirculation eddies utilize conservation of momentum and mass assumptions. Increasing the mass flow rate of either fuel or combustion air increases both the jet velocity and momentum for a fixed burner configuration. Thus, differentiating between gas velocity and momentum is important when evaluating flame stability under various operating conditions. The research efforts described herein are part of an ongoing project directed at evaluating the effect of flame aerodynamics on NO{sub x} emissions from coal fired burners in a systematic manner. This research includes both experimental and modeling efforts being performed at the University of Arizona in collaboration with Purdue University. The objective of this effort is to develop rational design tools for <span class="hlt">optimizing</span> low NO{sub x} burners. Experimental studies include both cold-and hot-flow evaluations of the following parameters: primary and secondary inlet air velocity, coal concentration in the primary air, coal <span class="hlt">particle</span> size distribution and flame holder geometry. Hot-flow experiments will also evaluate the effect of wall temperature on burner performance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ArFKT..22....9A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ArFKT..22....9A"><span id="translatedtitle"><span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> algorithm based low cost magnetometer calibration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ali, A. S.; Siddharth, S., Syed, Z., El-Sheimy, N.</p> <p>2011-12-01</p> <p>Inertial Navigation Systems (INS) consist of accelerometers, gyroscopes and a microprocessor provide inertial digital data from which position and orientation is obtained by integrating the specific forces and rotation rates. In addition to the accelerometers and gyroscopes, magnetometers can be used to derive the absolute user heading based on Earth's magnetic field. Unfortunately, the measurements of the magnetic field obtained with low cost sensors are corrupted by several errors including manufacturing defects and external electro-magnetic fields. Consequently, proper calibration of the magnetometer is required to achieve high accuracy heading measurements. In this paper, a <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) based calibration algorithm is presented to estimate the values of the bias and scale factor of low cost magnetometer. The main advantage of this technique is the use of the artificial intelligence which does not need any error modeling or awareness of the nonlinearity. The estimated bias and scale factor errors from the proposed algorithm improve the heading accuracy and the results are also statistically significant. Also, it can help in the development of the Pedestrian Navigation Devices (PNDs) when combined with the INS and GPS/Wi-Fi especially in the indoor environments</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JPhCS.540a2007W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JPhCS.540a2007W"><span id="translatedtitle">High-Dimensional Adaptive <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> on Heterogeneous Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wachowiak, M. P.; Sarlo, B. B.; Lambe Foster, A. E.</p> <p>2014-10-01</p> <p>Much work has recently been reported in parallel GPU-based <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO). Motivated by the encouraging results of these investigations, while also recognizing the limitations of GPU-based methods for big problems using a large amount of data, this paper explores the efficacy of employing other types of parallel hardware for PSO. Most commodity systems feature a variety of architectures whose high-performance capabilities can be exploited. In this paper, high-dimensional problems and those that employ a large amount of external data are explored within the context of heterogeneous systems. Large problems are decomposed into constituent components, and analyses are undertaken of which components would benefit from multi-core or GPU parallelism. The current study therefore provides another demonstration that "supercomputing on a budget" is possible when subtasks of large problems are run on hardware most suited to these tasks. Experimental results show that large speedups can be achieved on high dimensional, data-intensive problems. Cost functions must first be analysed for parallelization opportunities, and assigned hardware based on the particular task.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/316373','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/316373"><span id="translatedtitle">Removal of iron oxide <span class="hlt">particles</span> in a gas stream by means of a magnetically stabilized granular <span class="hlt">filter</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rodriguez, J.M.; Macias-Machin, A.; Alvaro, A.; Sanchez, J.R.; Estevez, A.M.</p> <p>1999-01-01</p> <p>The present study deals with the influence of diverse operating variables such as gas velocity, height of the bed, magnetic field strength, and <span class="hlt">particle</span> bounce on separation of fine dust <span class="hlt">particles</span> (iron oxide) in magnetically stabilized granular <span class="hlt">filters</span> (MSF). The collection results are more effective when the height of the MSF and dust sizes increase. Investigations concerning the magnetic field behavior have shown that the collection efficiency increases when the magnetic field also increases. And the increase of the magnetic field strength has shown that <span class="hlt">particle</span> bounce significantly decreases and the adhesion probability of the MSF improves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/862917','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/862917"><span id="translatedtitle"><span class="hlt">Filtering</span> coal-derived oil through a <span class="hlt">filter</span> media precoated with <span class="hlt">particles</span> partially solubilized by said oil</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Rodgers, Billy R.; Edwards, Michael S.</p> <p>1977-01-01</p> <p>Solids such as char, ash, and refractory organic compounds are removed from coal-derived liquids from coal liquefaction processes by the pressure precoat filtration method using <span class="hlt">particles</span> of 85-350 mesh material selected from the group of bituminous coal, anthracite coal, lignite, and devolatilized coals as precoat materials and as body feed to the unfiltered coal-derived liquid.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MSSP...75..301J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MSSP...75..301J"><span id="translatedtitle"><span class="hlt">Particle</span> <span class="hlt">filter</span> based hybrid prognostics for health monitoring of uncertain systems in bond graph framework</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jha, Mayank Shekhar; Dauphin-Tanguy, G.; Ould-Bouamama, B.</p> <p>2016-06-01</p> <p>The paper's main objective is to address the problem of health monitoring of system parameters in Bond Graph (BG) modeling framework, by exploiting its structural and causal properties. The system in feedback control loop is considered uncertain globally. Parametric uncertainty is modeled in interval form. The system parameter is undergoing degradation (prognostic candidate) and its degradation model is assumed to be known a priori. The detection of degradation commencement is done in a passive manner which involves interval valued robust adaptive thresholds over the nominal part of the uncertain BG-derived interval valued analytical redundancy relations (I-ARRs). The latter forms an efficient diagnostic module. The prognostics problem is cast as joint state-parameter estimation problem, a hybrid prognostic approach, wherein the fault model is constructed by considering the statistical degradation model of the system parameter (prognostic candidate). The observation equation is constructed from nominal part of the I-ARR. Using <span class="hlt">particle</span> <span class="hlt">filter</span> (PF) algorithms; the estimation of state of health (state of prognostic candidate) and associated hidden time-varying degradation progression parameters is achieved in probabilistic terms. A simplified variance adaptation scheme is proposed. Associated uncertainties which arise out of noisy measurements, parametric degradation process, environmental conditions etc. are effectively managed by PF. This allows the production of effective predictions of the remaining useful life of the prognostic candidate with suitable confidence bounds. The effectiveness of the novel methodology is demonstrated through simulations and experiments on a mechatronic system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GeCar..63..219Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GeCar..63..219Z"><span id="translatedtitle">Usefulness of Nonlinear Interpolation and <span class="hlt">Particle</span> <span class="hlt">Filter</span> in Zigbee Indoor Positioning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Xiang; Wu, Helei; Uradziński, Marcin</p> <p>2014-12-01</p> <p>The key to fingerprint positioning algorithm is establishing effective fingerprint information database based on different reference nodes of received signal strength indicator (RSSI). Traditional method is to set the location area calibration multiple information sampling points, and collection of a large number sample data what is very time consuming. With Zigbee sensor networks as platform, considering the influence of positioning signal interference, we proposed an improved algorithm of getting virtual database based on polynomial interpolation, while the pre-estimated result was disposed by <span class="hlt">particle</span> <span class="hlt">filter</span>. Experimental result shows that this method can generate a quick, simple fine-grained localization information database, and improve the positioning accuracy at the same time. Kluczem do algorytmu pozycjonowania wykorzystującego metodę fi ngerprinting jest ustanowienie skutecznej bazy danych na podstawie informacji z radiowych nadajników referencyjnych przy wykorzystaniu wskaźnika mocy odbieranego sygnału (RSSI). Tradycyjna metoda oparta jest na przeprowadzeniu kalibracji obszaru lokalizacji na podstawie wielu punktów pomiarowych i otrzymaniu dużej liczby próbek, co jest bardzo czasochłonne.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JNEng..12d6018S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JNEng..12d6018S"><span id="translatedtitle">Incorporating advanced language models into the P300 speller using <span class="hlt">particle</span> <span class="hlt">filtering</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Speier, W.; Arnold, C. W.; Deshpande, A.; Knall, J.; Pouratian, N.</p> <p>2015-08-01</p> <p>Objective. The P300 speller is a common brain-computer interface (BCI) application designed to communicate language by detecting event related potentials in a subject’s electroencephalogram signal. Information about the structure of natural language can be valuable for BCI communication, but attempts to use this information have thus far been limited to rudimentary n-gram models. While more sophisticated language models are prevalent in natural language processing literature, current BCI analysis methods based on dynamic programming cannot handle their complexity. Approach. Sampling methods can overcome this complexity by estimating the posterior distribution without searching the entire state space of the model. In this study, we implement sequential importance resampling, a commonly used <span class="hlt">particle</span> <span class="hlt">filtering</span> (PF) algorithm, to integrate a probabilistic automaton language model. Main result. This method was first evaluated offline on a dataset of 15 healthy subjects, which showed significant increases in speed and accuracy when compared to standard classification methods as well as a recently published approach using a hidden Markov model (HMM). An online pilot study verified these results as the average speed and accuracy achieved using the PF method was significantly higher than that using the HMM method. Significance. These findings strongly support the integration of domain-specific knowledge into BCI classification to improve system performance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22067364','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22067364"><span id="translatedtitle"><span class="hlt">Particle</span> <span class="hlt">filter</span> with a mode tracker for visual tracking across illumination changes.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Das, Samarjit; Kale, Amit; Vaswani, Namrata</p> <p>2012-04-01</p> <p>In this correspondence, our goal is to develop a visual tracking algorithm that is able to track moving objects in the presence of illumination variations in the scene and that is robust to occlusions. We treat the illumination and motion ( x-y translation and scale) parameters as the unknown "state" sequence. The observation is the entire image, and the observation model allows for occasional occlusions (modeled as outliers). The nonlinearity and multimodality of the observation model necessitate the use of a <span class="hlt">particle</span> <span class="hlt">filter</span> (PF). Due to the inclusion of illumination parameters, the state dimension increases, thus making regular PFs impractically expensive. We show that the recently proposed approach using a PF with a mode tracker can be used here since, even in most occlusion cases, the posterior of illumination conditioned on motion and the previous state is unimodal and quite narrow. The key idea is to importance sample on the motion states while approximating importance sampling by posterior mode tracking for estimating illumination. Experiments demonstrate the advantage of the proposed algorithm over existing PF-based approaches for various face and vehicle tracking. We are also able to detect illumination model changes, e.g., those due to transition from shadow to sunlight or vice versa by using the generalized expected log-likelihood statistics and successfully compensate for it without ever loosing track. PMID:22067364</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006EJASP2007..295L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006EJASP2007..295L"><span id="translatedtitle"><span class="hlt">Particle</span> <span class="hlt">Filter</span> with Integrated Voice Activity Detection for Acoustic Source Tracking</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lehmann, Eric A.; Johansson, Anders M.</p> <p>2006-12-01</p> <p>In noisy and reverberant environments, the problem of acoustic source localisation and tracking (ASLT) using an array of microphones presents a number of challenging difficulties. One of the main issues when considering real-world situations involving human speakers is the temporally discontinuous nature of speech signals: the presence of silence gaps in the speech can easily misguide the tracking algorithm, even in practical environments with low to moderate noise and reverberation levels. A natural extension of currently available sound source tracking algorithms is the integration of a voice activity detection (VAD) scheme. We describe a new ASLT algorithm based on a <span class="hlt">particle</span> <span class="hlt">filtering</span> (PF) approach, where VAD measurements are fused within the statistical framework of the PF implementation. Tracking accuracy results for the proposed method is presented on the basis of synthetic audio samples generated with the image method, whereas performance results obtained with a real-time implementation of the algorithm, and using real audio data recorded in a reverberant room, are published elsewhere. Compared to a previously proposed PF algorithm, the experimental results demonstrate the improved robustness of the method described in this work when tracking sources emitting real-world speech signals, which typically involve significant silence gaps between utterances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3188653','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3188653"><span id="translatedtitle">Multisource modeling of flattening <span class="hlt">filter</span> free (FFF) beam and the <span class="hlt">optimization</span> of model parameters</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Cho, Woong; Kielar, Kayla N.; Mok, Ed; Xing, Lei; Park, Jeong-Hoon; Jung, Won-Gyun; Suh, Tae-Suk</p> <p>2011-01-01</p> <p>Purpose: With the introduction of flattening <span class="hlt">filter</span> free (FFF) linear accelerators to radiation oncology, new analytical source models for a FFF beam applicable to current treatment planning systems is needed. In this work, a multisource model for the FFF beam and the <span class="hlt">optimization</span> of involved model parameters were designed. Methods: The model is based on a previous three source model proposed by Yang [“A three-source model for the calculation of head scatter factors,” Med. Phys. 29, 2024–2033 (2002)]. An off axis ratio (OAR) of photon fluence was introduced to the primary source term to generate cone shaped profiles. The parameters of the source model were determined from measured head scatter factors using a line search <span class="hlt">optimization</span> technique. The OAR of the photon fluence was determined from a measured dose profile of a 40×40 cm2 field size with the same <span class="hlt">optimization</span> technique, but a new method to acquire gradient terms for OARs was developed to enhance the speed of the <span class="hlt">optimization</span> process. The improved model was validated with measured dose profiles from 3×3 to 40×40 cm2 field sizes at 6 and 10 MV from a TrueBeam™ STx linear accelerator. Furthermore, planar dose distributions for clinically used radiation fields were also calculated and compared to measurements using a 2D array detector using the gamma index method. Results: All dose values for the calculated profiles agreed with the measured dose profiles within 0.5% at 6 and 10 MV beams, except for some low dose regions for larger field sizes. A slight overestimation was seen in the lower penumbra region near the field edge for the large field sizes by 1%–4%. The planar dose calculations showed comparable passing rates (>98%) when the criterion of the gamma index method was selected to be 3%∕3 mm. Conclusions: The developed source model showed good agreements between measured and calculated dose distributions. The model is easily applicable to any other linear accelerator using FFF beams as the required data include only the measured PDD, dose profiles, and output factors for various field sizes, which are easily acquired during conventional beam commissioning process. PMID:21626926</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.5797B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.5797B"><span id="translatedtitle">Improved design and <span class="hlt">optimization</span> of subsurface flow constructed wetlands and sand <span class="hlt">filters</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brovelli, A.; Carranza-Díaz, O.; Rossi, L.; Barry, D. A.</p> <p>2010-05-01</p> <p>Subsurface flow constructed wetlands and sand <span class="hlt">filters</span> are engineered systems capable of eliminating a wide range of pollutants from wastewater. These devices are easy to operate, flexible and have low maintenance costs. For these reasons, they are particularly suitable for small settlements and isolated farms and their use has substantially increased in the last 15 years. Furthermore, they are also becoming used as a tertiary - polishing - step in traditional treatment plants. Recent work observed that research is however still necessary to understand better the biogeochemical processes occurring in the porous substrate, their mutual interactions and feedbacks, and ultimately to identify the <span class="hlt">optimal</span> conditions to degrade or remove from the wastewater both traditional and anthropogenic recalcitrant pollutants, such as hydrocarbons, pharmaceuticals, personal care products. <span class="hlt">Optimal</span> pollutant elimination is achieved if the contact time between microbial biomass and the contaminated water is sufficiently long. The contact time depends on the hydraulic residence time distribution (HRTD) and is controlled by the hydrodynamic properties of the system. Previous reports noted that poor hydrodynamic behaviour is frequent, with water flowing mainly through preferential paths resulting in a broad HRTD. In such systems the flow rate must be decreased to allow a sufficient proportion of the wastewater to experience the minimum residence time. The pollutant removal efficiency can therefore be significantly reduced, potentially leading to the failure of the system. The aim of this work was to analyse the effect of the heterogeneous distribution of the hydraulic properties of the porous substrate on the HRTD and treatment efficiency, and to develop an improved design methodology to reduce the risk of system failure and to <span class="hlt">optimize</span> existing systems showing poor hydrodynamics. Numerical modelling was used to evaluate the effect of substrate heterogeneity on the breakthrough curves of both a conservative tracer and a reactive organic compound. Random, spatially correlated hydraulic conductivity fields following a log-normal distribution were generated to represent the heterogeneous distribution of the hydraulic properties. The effect of the variance of the hydraulic conductivity distribution, as well as the aspect ratio of the correlation lengths were analyzed and compared to experimental findings. The proposed design methodology is based on the target hydraulic residence time, that is, the residence time required to achieve the degradation of the contaminants. The effect of the heterogeneity is accounted for using a Monte Carlo approach. From the analysis of the simulation results the probability of failure of the system can be estimated and used to design a new system or <span class="hlt">optimize</span> existing systems. The methodology was illustrated using a realistic test case with water contaminated with benzene.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010LNCS.6466..440S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010LNCS.6466..440S"><span id="translatedtitle">A <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> Algorithm for <span class="hlt">Optimal</span> Operating Parameters of VMI Systems in a Two-Echelon Supply Chain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sue-Ann, Goh; Ponnambalam, S. G.</p> <p></p> <p>This paper focuses on the operational issues of a Two-echelon Single-Vendor-Multiple-Buyers Supply chain (TSVMBSC) under vendor managed inventory (VMI) mode of operation. To determine the <span class="hlt">optimal</span> sales quantity for each buyer in TSVMBC, a mathematical model is formulated. Based on the <span class="hlt">optimal</span> sales quantity can be obtained and the <span class="hlt">optimal</span> sales price that will determine the <span class="hlt">optimal</span> channel profit and contract price between the vendor and buyer. All this parameters depends upon the understanding of the revenue sharing between the vendor and buyers. A <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) is proposed for this problem. Solutions obtained from PSO is compared with the best known results reported in literature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23741525','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23741525"><span id="translatedtitle">Design <span class="hlt">optimization</span> of pin fin geometry using <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> algorithm.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hamadneh, Nawaf; Khan, Waqar A; Sathasivam, Saratha; Ong, Hong Choon</p> <p>2013-01-01</p> <p><span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> (PSO) is employed to investigate the overall performance of a pin fin.The following study will examine the effect of governing parameters on overall thermal/fluid performance associated with different fin geometries, including, rectangular plate fins as well as square, circular, and elliptical pin fins. The idea of entropy generation minimization, EGM is employed to combine the effects of thermal resistance and pressure drop within the heat sink. A general dimensionless expression for the entropy generation rate is obtained by considering a control volume around the pin fin including base plate and applying the conservations equations for mass and energy with the entropy balance. Selected fin geometries are examined for the heat transfer, fluid friction, and the minimum entropy generation rate corresponding to different parameters including axis ratio, aspect ratio, and Reynolds number. The results clearly indicate that the preferred fin profile is very dependent on these parameters. PMID:23741525</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3669212','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3669212"><span id="translatedtitle">Design <span class="hlt">Optimization</span> of Pin Fin Geometry Using <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> Algorithm</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hamadneh, Nawaf; Khan, Waqar A.; Sathasivam, Saratha; Ong, Hong Choon</p> <p>2013-01-01</p> <p><span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> (PSO) is employed to investigate the overall performance of a pin fin.The following study will examine the effect of governing parameters on overall thermal/fluid performance associated with different fin geometries, including, rectangular plate fins as well as square, circular, and elliptical pin fins. The idea of entropy generation minimization, EGM is employed to combine the effects of thermal resistance and pressure drop within the heat sink. A general dimensionless expression for the entropy generation rate is obtained by considering a control volume around the pin fin including base plate and applying the conservations equations for mass and energy with the entropy balance. Selected fin geometries are examined for the heat transfer, fluid friction, and the minimum entropy generation rate corresponding to different parameters including axis ratio, aspect ratio, and Reynolds number. The results clearly indicate that the preferred fin profile is very dependent on these parameters. PMID:23741525</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4650781','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4650781"><span id="translatedtitle">Spatial mapping of the biologic effectiveness of scanned <span class="hlt">particle</span> beams: towards biologically <span class="hlt">optimized</span> <span class="hlt">particle</span> therapy</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Guan, Fada; Bronk, Lawrence; Titt, Uwe; Lin, Steven H.; Mirkovic, Dragan; Kerr, Matthew D.; Zhu, X. Ronald; Dinh, Jeffrey; Sobieski, Mary; Stephan, Clifford; Peeler, Christopher R.; Taleei, Reza; Mohan, Radhe; Grosshans, David R.</p> <p>2015-01-01</p> <p>The physical properties of <span class="hlt">particles</span> used in radiation therapy, such as protons, have been well characterized, and their dose distributions are superior to photon-based treatments. However, proton therapy may also have inherent biologic advantages that have not been capitalized on. Unlike photon beams, the linear energy transfer (LET) and hence biologic effectiveness of <span class="hlt">particle</span> beams varies along the beam path. Selective placement of areas of high effectiveness could enhance tumor cell kill and simultaneously spare normal tissues. However, previous methods for mapping spatial variations in biologic effectiveness are time-consuming and often yield inconsistent results with large uncertainties. Thus the data needed to accurately model relative biological effectiveness to guide novel treatment planning approaches are limited. We used Monte Carlo modeling and high-content automated clonogenic survival assays to spatially map the biologic effectiveness of scanned proton beams with high accuracy and throughput while minimizing biological uncertainties. We found that the relationship between cell kill, dose, and LET, is complex and non-unique. Measured biologic effects were substantially greater than in most previous reports, and non-linear surviving fraction response was observed even for the highest LET values. Extension of this approach could generate data needed to <span class="hlt">optimize</span> proton therapy plans incorporating variable RBE. PMID:25984967</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25984967','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25984967"><span id="translatedtitle">Spatial mapping of the biologic effectiveness of scanned <span class="hlt">particle</span> beams: towards biologically <span class="hlt">optimized</span> <span class="hlt">particle</span> therapy.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Guan, Fada; Bronk, Lawrence; Titt, Uwe; Lin, Steven H; Mirkovic, Dragan; Kerr, Matthew D; Zhu, X Ronald; Dinh, Jeffrey; Sobieski, Mary; Stephan, Clifford; Peeler, Christopher R; Taleei, Reza; Mohan, Radhe; Grosshans, David R</p> <p>2015-01-01</p> <p>The physical properties of <span class="hlt">particles</span> used in radiation therapy, such as protons, have been well characterized, and their dose distributions are superior to photon-based treatments. However, proton therapy may also have inherent biologic advantages that have not been capitalized on. Unlike photon beams, the linear energy transfer (LET) and hence biologic effectiveness of <span class="hlt">particle</span> beams varies along the beam path. Selective placement of areas of high effectiveness could enhance tumor cell kill and simultaneously spare normal tissues. However, previous methods for mapping spatial variations in biologic effectiveness are time-consuming and often yield inconsistent results with large uncertainties. Thus the data needed to accurately model relative biological effectiveness to guide novel treatment planning approaches are limited. We used Monte Carlo modeling and high-content automated clonogenic survival assays to spatially map the biologic effectiveness of scanned proton beams with high accuracy and throughput while minimizing biological uncertainties. We found that the relationship between cell kill, dose, and LET, is complex and non-unique. Measured biologic effects were substantially greater than in most previous reports, and non-linear surviving fraction response was observed even for the highest LET values. Extension of this approach could generate data needed to <span class="hlt">optimize</span> proton therapy plans incorporating variable RBE. PMID:25984967</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050239001','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050239001"><span id="translatedtitle">An <span class="hlt">Optimal</span> Orthogonal Decomposition Method for Kalman <span class="hlt">Filter</span>-Based Turbofan Engine Thrust Estimation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Litt, Jonathan S.</p> <p>2005-01-01</p> <p>A new linear point design technique is presented for the determination of tuning parameters that enable the <span class="hlt">optimal</span> estimation of unmeasured engine outputs such as thrust. The engine s performance is affected by its level of degradation, generally described in terms of unmeasurable health parameters related to each major engine component. Accurate thrust reconstruction depends upon knowledge of these health parameters, but there are usually too few sensors to be able to estimate their values. In this new technique, a set of tuning parameters is determined which accounts for degradation by representing the overall effect of the larger set of health parameters as closely as possible in a least squares sense. The technique takes advantage of the properties of the singular value decomposition of a matrix to generate a tuning parameter vector of low enough dimension that it can be estimated by a Kalman <span class="hlt">filter</span>. A concise design procedure to generate a tuning vector that specifically takes into account the variables of interest is presented. An example demonstrates the tuning parameters ability to facilitate matching of both measured and unmeasured engine outputs, as well as state variables. Additional properties of the formulation are shown to lend themselves well to diagnostics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20100042588&hterms=Kalman&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DKalman','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20100042588&hterms=Kalman&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DKalman"><span id="translatedtitle">An <span class="hlt">Optimal</span> Orthogonal Decomposition Method for Kalman <span class="hlt">Filter</span>-Based Turbofan Engine Thrust Estimation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Litt, Jonathan S.</p> <p>2007-01-01</p> <p>A new linear point design technique is presented for the determination of tuning parameters that enable the <span class="hlt">optimal</span> estimation of unmeasured engine outputs, such as thrust. The engine's performance is affected by its level of degradation, generally described in terms of unmeasurable health parameters related to each major engine component. Accurate thrust reconstruction depends on knowledge of these health parameters, but there are usually too few sensors to be able to estimate their values. In this new technique, a set of tuning parameters is determined that accounts for degradation by representing the overall effect of the larger set of health parameters as closely as possible in a least squares sense. The technique takes advantage of the properties of the singular value decomposition of a matrix to generate a tuning parameter vector of low enough dimension that it can be estimated by a Kalman <span class="hlt">filter</span>. A concise design procedure to generate a tuning vector that specifically takes into account the variables of interest is presented. An example demonstrates the tuning parameters ability to facilitate matching of both measured and unmeasured engine outputs, as well as state variables. Additional properties of the formulation are shown to lend themselves well to diagnostics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20080047455&hterms=Kalman&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DKalman','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20080047455&hterms=Kalman&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DKalman"><span id="translatedtitle">An <span class="hlt">Optimal</span> Orthogonal Decomposition Method for Kalman <span class="hlt">Filter</span>-Based Turbofan Engine Thrust Estimation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Litt, Jonathan S.</p> <p>2007-01-01</p> <p>A new linear point design technique is presented for the determination of tuning parameters that enable the <span class="hlt">optimal</span> estimation of unmeasured engine outputs, such as thrust. The engine s performance is affected by its level of degradation, generally described in terms of unmeasurable health parameters related to each major engine component. Accurate thrust reconstruction depends on knowledge of these health parameters, but there are usually too few sensors to be able to estimate their values. In this new technique, a set of tuning parameters is determined that accounts for degradation by representing the overall effect of the larger set of health parameters as closely as possible in a least-squares sense. The technique takes advantage of the properties of the singular value decomposition of a matrix to generate a tuning parameter vector of low enough dimension that it can be estimated by a Kalman <span class="hlt">filter</span>. A concise design procedure to generate a tuning vector that specifically takes into account the variables of interest is presented. An example demonstrates the tuning parameters ability to facilitate matching of both measured and unmeasured engine outputs, as well as state variables. Additional properties of the formulation are shown to lend themselves well to diagnostics.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22453408','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22453408"><span id="translatedtitle"><span class="hlt">Optimizing</span> single mode robustness of the distributed modal <span class="hlt">filtering</span> rod fiber amplifier.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jørgensen, Mette Marie; Petersen, Sidsel Rübner; Laurila, Marko; Lægsgaard, Jesper; Alkeskjold, Thomas Tanggaard</p> <p>2012-03-26</p> <p>High-power fiber amplifiers for pulsed applications require large mode area (LMA) fibers having high pump absorption and near diffraction limited output. Photonic crystal fibers allow realization of short LMA fiber amplifiers having high pump absorption through a pump cladding that is decoupled from the outer fiber diameter. However, achieving ultra low NA for single mode (SM) guidance is challenging, thus different design strategies must be applied. The distributed modal <span class="hlt">filtering</span> (DMF) design enables SM guidance in ultra low NA fibers with very large cores, where large preform tolerances can be compensated during the fiber draw. Design <span class="hlt">optimization</span> of the SM bandwidth of the DMF rod fiber is presented. Analysis of band gap properties results in a fourfold increase of the SM bandwidth compared to previous results, achieved by utilizing the first band of cladding modes, which can cover a large fraction of the Yb emission band including wavelengths of 1030 nm and 1064 nm. Design parameters tolerating refractive index fabrication uncertainties of ± 10⁻⁴ are targeted to yield stable SM bandwidths. PMID:22453408</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/7270999','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/7270999"><span id="translatedtitle">Study of the effect of humidity, <span class="hlt">particle</span> hygroscopicity and size on the mass loading capacity of HEPA <span class="hlt">filters</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gupta, A.</p> <p>1992-01-01</p> <p>The effect of humidity, <span class="hlt">particle</span> hygroscopicity and size on the mass loading capacity of glass fiber HEPA <span class="hlt">filters</span> has been studied. At humidifies above the deliquescent point, the pressure drop across the HEPA <span class="hlt">filter</span> increased non-linearly with the areal loading density (mass collected/filtration area) of NaCl aerosol, thus significantly reducing the mass loading capacity of the <span class="hlt">filter</span> compared to dry hygroscopic or non-hygroscopic <span class="hlt">particle</span> mass loadings. The specific cake resistance, K{sub 2}, has been computed for different test conditions and used as a measure of the mass loading capacity. K. was found to decrease with increasing humidity for the non-hygroscopic aluminum oxide <span class="hlt">particles</span> and the hygroscopic NaCl <span class="hlt">particles</span> (at humidities below the deliquescent point). It is postulated that an increase in humidity leads to the formation of a more open particulate cake which lowers the pressure drop for a given mass loading. A formula for predicting K{sub 2} for lognormally distributed aerosols (parameters obtained from impactor data) is derived. The resistance factor, R, calculated using this formula was compared to the theoretical R calculated using the Rudnick-Happel expression. For the non-hygroscopic aluminum oxide the agreement was good but for the hygroscopic sodium chloride, due to large variation in the cake porosity estimates, the agreement was poor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10172571','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10172571"><span id="translatedtitle">Study of the effect of humidity, <span class="hlt">particle</span> hygroscopicity and size on the mass loading capacity of HEPA <span class="hlt">filters</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gupta, A.</p> <p>1992-09-01</p> <p>The effect of humidity, <span class="hlt">particle</span> hygroscopicity and size on the mass loading capacity of glass fiber HEPA <span class="hlt">filters</span> has been studied. At humidifies above the deliquescent point, the pressure drop across the HEPA <span class="hlt">filter</span> increased non-linearly with the areal loading density (mass collected/filtration area) of NaCl aerosol, thus significantly reducing the mass loading capacity of the <span class="hlt">filter</span> compared to dry hygroscopic or non-hygroscopic <span class="hlt">particle</span> mass loadings. The specific cake resistance, K{sub 2}, has been computed for different test conditions and used as a measure of the mass loading capacity. K. was found to decrease with increasing humidity for the non-hygroscopic aluminum oxide <span class="hlt">particles</span> and the hygroscopic NaCl <span class="hlt">particles</span> (at humidities below the deliquescent point). It is postulated that an increase in humidity leads to the formation of a more open particulate cake which lowers the pressure drop for a given mass loading. A formula for predicting K{sub 2} for lognormally distributed aerosols (parameters obtained from impactor data) is derived. The resistance factor, R, calculated using this formula was compared to the theoretical R calculated using the Rudnick-Happel expression. For the non-hygroscopic aluminum oxide the agreement was good but for the hygroscopic sodium chloride, due to large variation in the cake porosity estimates, the agreement was poor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21807026','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21807026"><span id="translatedtitle">Dimension reduction: additional benefit of an <span class="hlt">optimal</span> <span class="hlt">filter</span> for independent component analysis to extract event-related potentials.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cong, Fengyu; Leppänen, Paavo H T; Astikainen, Piia; Hämäläinen, Jarmo; Hietanen, Jari K; Ristaniemi, Tapani</p> <p>2011-09-30</p> <p>The present study addresses benefits of a linear <span class="hlt">optimal</span> <span class="hlt">filter</span> (OF) for independent component analysis (ICA) in extracting brain event-related potentials (ERPs). A <span class="hlt">filter</span> such as the digital <span class="hlt">filter</span> is usually considered as a denoising tool. Actually, in <span class="hlt">filtering</span> ERP recordings by an OF, the ERP' topography should not be changed by the <span class="hlt">filter</span>, and the output should also be able to be modeled by the linear transformation. Moreover, an OF designed for a specific ERP source or component may remove noise, as well as reduce the overlap of sources and even reject some non-targeted sources in the ERP recordings. The OF can thus accomplish both the denoising and dimension reduction (reducing the number of sources) simultaneously. We demonstrated these effects using two datasets, one containing visual and the other auditory ERPs. The results showed that the method including OF and ICA extracted much more reliable components than the sole ICA without OF did, and that OF removed some non-targeted sources and made the underdetermined model of EEG recordings approach to the determined one. Thus, we suggest designing an OF based on the properties of an ERP to <span class="hlt">filter</span> recordings before using ICA decomposition to extract the targeted ERP component. PMID:21807026</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19720014625&hterms=pigments&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dpigments','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19720014625&hterms=pigments&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dpigments"><span id="translatedtitle">The determination and <span class="hlt">optimization</span> of (rutile) pigment <span class="hlt">particle</span> size distributions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Richards, L. W.</p> <p>1972-01-01</p> <p>A light scattering <span class="hlt">particle</span> size test which can be used with materials having a broad <span class="hlt">particle</span> size distribution is described. This test is useful for pigments. The relation between the <span class="hlt">particle</span> size distribution of a rutile pigment and its optical performance in a gray tint test at low pigment concentration is calculated and compared with experimental data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4667038','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4667038"><span id="translatedtitle"><span class="hlt">Optimal</span> multi-floor plant layout based on the mathematical programming and <span class="hlt">particle</span> swarm <span class="hlt">optimization</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>LEE, Chang Jun</p> <p>2015-01-01</p> <p>In the fields of researches associated with plant layout <span class="hlt">optimization</span>, the main goal is to minimize the costs of pipelines and pumping between connecting equipment under various constraints. However, what is the lacking of considerations in previous researches is to transform various heuristics or safety regulations into mathematical equations. For example, proper safety distances between equipments have to be complied for preventing dangerous accidents on a complex plant. Moreover, most researches have handled single-floor plant. However, many multi-floor plants have been constructed for the last decade. Therefore, the proper algorithm handling various regulations and multi-floor plant should be developed. In this study, the Mixed Integer Non-Linear Programming (MINLP) problem including safety distances, maintenance spaces, etc. is suggested based on mathematical equations. The objective function is a summation of pipeline and pumping costs. Also, various safety and maintenance issues are transformed into inequality or equality constraints. However, it is really hard to solve this problem due to complex nonlinear constraints. Thus, it is impossible to use conventional MINLP solvers using derivatives of equations. In this study, the <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) technique is employed. The ethylene oxide plant is illustrated to verify the efficacy of this study. PMID:26027708</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26027708','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26027708"><span id="translatedtitle"><span class="hlt">Optimal</span> multi-floor plant layout based on the mathematical programming and <span class="hlt">particle</span> swarm <span class="hlt">optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lee, Chang Jun</p> <p>2015-01-01</p> <p>In the fields of researches associated with plant layout <span class="hlt">optimization</span>, the main goal is to minimize the costs of pipelines and pumping between connecting equipment under various constraints. However, what is the lacking of considerations in previous researches is to transform various heuristics or safety regulations into mathematical equations. For example, proper safety distances between equipments have to be complied for preventing dangerous accidents on a complex plant. Moreover, most researches have handled single-floor plant. However, many multi-floor plants have been constructed for the last decade. Therefore, the proper algorithm handling various regulations and multi-floor plant should be developed. In this study, the Mixed Integer Non-Linear Programming (MINLP) problem including safety distances, maintenance spaces, etc. is suggested based on mathematical equations. The objective function is a summation of pipeline and pumping costs. Also, various safety and maintenance issues are transformed into inequality or equality constraints. However, it is really hard to solve this problem due to complex nonlinear constraints. Thus, it is impossible to use conventional MINLP solvers using derivatives of equations. In this study, the <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) technique is employed. The ethylene oxide plant is illustrated to verify the efficacy of this study. PMID:26027708</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24766596','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24766596"><span id="translatedtitle">Removal of <span class="hlt">particles</span> in organic <span class="hlt">filters</span> in experimental treatment systems for domestic wastewater and black water.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Todt, Daniel; Jenssen, Petter D; Klemenčič, Aleksandra Krivograd; Oarga, Andreea; Bulc, Tjaša Griessler</p> <p>2014-01-01</p> <p>This study assesses the total suspended solids (TSS) retention capacity of different organic <span class="hlt">filter</span> media for two potential applications: (i) a polishing unit for package treatment plants and (ii) a pretreatment for blackwater from low-flushing toilets. The results showed that the peat <span class="hlt">filter</span> media used can be significantly improved in terms of structural stability and TSS removal capacity by mixing it with sawdust. Most of the TSS accumulated in the upper part of the <span class="hlt">filter</span> material, and <span class="hlt">filter</span> thickness exceeding 15 cm had no statistically significant effect (P < 0.1) on the TSS treatment performance. The experimental system reached a TSS reduction of 60-70% for blackwater and 80-90% for simulated effluent peaks from a package treatment plant. The main challenge of a full-scale application of an organic <span class="hlt">filter</span> is the issue of clogging, especially when treating concentrated blackwater. However, this work indicates that a clogged <span class="hlt">filter</span> media can be regenerated by mixing the uppermost <span class="hlt">filter</span> layer without significant loss of <span class="hlt">filter</span> performance regarding TSS. More research is needed to develop an appropriate mechanical unit for automatic <span class="hlt">filter</span> media regeneration. PMID:24766596</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013aero.confE..97S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013aero.confE..97S"><span id="translatedtitle"><span class="hlt">Optimized</span> FIR <span class="hlt">filters</span> for digital pulse compression of biphase codes with low sidelobes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sanal, M.; Kuloor, R.; Sagayaraj, M. J.</p> <p></p> <p>In miniaturized radars where power, real estate, speed and low cost are tight constraints and Doppler tolerance is not a major concern biphase codes are popular and FIR <span class="hlt">filter</span> is used for digital pulse compression (DPC) implementation to achieve required range resolution. Disadvantage of low peak to sidelobe ratio (PSR) of biphase codes can be overcome by linear programming for either single stage mismatched <span class="hlt">filter</span> or two stage approach i.e. matched <span class="hlt">filter</span> followed by sidelobe suppression <span class="hlt">filter</span> (SSF) <span class="hlt">filter</span>. Linear programming (LP) calls for longer <span class="hlt">filter</span> lengths to obtain desirable PSR. Longer the <span class="hlt">filter</span> length greater will be the number of multipliers, hence more will be the requirement of logic resources used in the FPGAs and many time becomes design challenge for system on chip (SoC) requirement. This requirement of multipliers can be brought down by clustering the tap weights of the <span class="hlt">filter</span> by kmeans clustering algorithm at the cost of few dB deterioration in PSR. The cluster centroid as tap weight reduces logic used in FPGA for FIR <span class="hlt">filters</span> to a great extent by reducing number of weight multipliers. Since k-means clustering is an iterative algorithm, centroid for weights cluster is different in different iterations and causes different clusters. This causes difference in clustering of weights and sometimes even it may happen that lesser number of multiplier and lesser length of <span class="hlt">filter</span> provide better PSR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25250730','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25250730"><span id="translatedtitle">Biologically induced deposition of fine suspended <span class="hlt">particles</span> by <span class="hlt">filter</span>-feeding bivalves in land-based industrial marine aquaculture wastewater.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhou, Yi; Zhang, Shaojun; Liu, Ying; Yang, Hongsheng</p> <p>2014-01-01</p> <p>Industrial aquaculture wastewater contains large quantities of suspended <span class="hlt">particles</span> that can be easily broken down physically. Introduction of macro-bio-<span class="hlt">filters</span>, such as bivalve <span class="hlt">filter</span> feeders, may offer the potential for treatment of fine suspended matter in industrial aquaculture wastewater. In this study, we employed two kinds of bivalve <span class="hlt">filter</span> feeders, the Pacific oyster Crassostrea gigas and the blue mussel Mytilus galloprovincialis, to deposit suspended solids from marine fish aquaculture wastewater in flow-through systems. Results showed that the biodeposition rate of suspended <span class="hlt">particles</span> by C. gigas (shell height: 8.67 ± 0.99 cm) and M. galloprovincialis (shell height: 4.43 ± 0.98 cm) was 77.84 ± 7.77 and 6.37 ± 0.67 mg ind(-1) • d(-1), respectively. The total solid suspension (TSS) deposition rates of oyster and mussel treatments were 3.73 ± 0.27 and 2.76 ± 0.20 times higher than that of the control treatment without bivalves, respectively. The TSS deposition rates of bivalve treatments were significantly higher than the natural sedimentation rate of the control treatment (P < 0.001). Furthermore, organic matter and C, N in the sediments of bivalve treatments were significantly lower than those in the sediments of the control (P < 0.05). It was suggested that the <span class="hlt">filter</span> feeders C. gigas and M. galloprovincialis had considerable potential to <span class="hlt">filter</span> and accelerate the deposition of suspended <span class="hlt">particles</span> from industrial aquaculture wastewater, and simultaneously yield value-added biological products. PMID:25250730</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4175470','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4175470"><span id="translatedtitle">Biologically Induced Deposition of Fine Suspended <span class="hlt">Particles</span> by <span class="hlt">Filter</span>-Feeding Bivalves in Land-Based Industrial Marine Aquaculture Wastewater</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhou, Yi; Zhang, Shaojun; Liu, Ying; Yang, Hongsheng</p> <p>2014-01-01</p> <p>Industrial aquaculture wastewater contains large quantities of suspended <span class="hlt">particles</span> that can be easily broken down physically. Introduction of macro-bio-<span class="hlt">filters</span>, such as bivalve <span class="hlt">filter</span> feeders, may offer the potential for treatment of fine suspended matter in industrial aquaculture wastewater. In this study, we employed two kinds of bivalve <span class="hlt">filter</span> feeders, the Pacific oyster Crassostrea gigas and the blue mussel Mytilus galloprovincialis, to deposit suspended solids from marine fish aquaculture wastewater in flow-through systems. Results showed that the biodeposition rate of suspended <span class="hlt">particles</span> by C. gigas (shell height: 8.67±0.99 cm) and M. galloprovincialis (shell height: 4.43±0.98 cm) was 77.84±7.77 and 6.37±0.67 mg ind−1•d−1, respectively. The total solid suspension (TSS) deposition rates of oyster and mussel treatments were 3.73±0.27 and 2.76±0.20 times higher than that of the control treatment without bivalves, respectively. The TSS deposition rates of bivalve treatments were significantly higher than the natural sedimentation rate of the control treatment (P<0.001). Furthermore, organic matter and C, N in the sediments of bivalve treatments were significantly lower than those in the sediments of the control (P<0.05). It was suggested that the <span class="hlt">filter</span> feeders C. gigas and M. galloprovincialis had considerable potential to <span class="hlt">filter</span> and accelerate the deposition of suspended <span class="hlt">particles</span> from industrial aquaculture wastewater, and simultaneously yield value-added biological products. PMID:25250730</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/989127','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/989127"><span id="translatedtitle">An Analysis of Field-Aged Diesel Particulate <span class="hlt">Filter</span> Performance: <span class="hlt">Particle</span> Emissions Before, During and After Regeneration</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Barone, Teresa L; Storey, John Morse; Domingo, Norberto</p> <p>2010-01-01</p> <p>A field-aged, passive diesel particulate <span class="hlt">filter</span> (DPF) employed in a school bus retrofit program was evaluated for emissions of <span class="hlt">particle</span> mass and number concentration before, during and after regeneration. For the <span class="hlt">particle</span> mass measurements, <span class="hlt">filter</span> samples were collected for gravimetric analysis with a partial flow sampling system, which sampled proportionally to the exhaust flow. Total number concentration and number-size distributions were measured by a condensation <span class="hlt">particle</span> counter and scanning mobility <span class="hlt">particle</span> sizer, respectively. The results of the evaluation show that the number concentration emissions decreased as the DPF became loaded with soot. However after soot removal by regeneration, the number concentration emissions were approximately 20 times greater, which suggests the importance of the soot layer in helping to trap <span class="hlt">particles</span>. Contrary to the number concentration results, <span class="hlt">particle</span> mass emissions decreased from 6 1 mg/hp-hr before regeneration to 3 2 mg/hp-hr after regeneration. This indicates that nanoparticles with diameter less than 50 nm may have been emitted after regeneration since these <span class="hlt">particles</span> contribute little to the total mass. Overall, average <span class="hlt">particle</span> emission reductions of 95% by mass and 10,000-fold by number concentration after four years of use provided evidence of the durability of a field-aged DPF. In contrast to previous reports for new DPFs in which elevated number concentrations occurred during the first 200 seconds of a transient cycle, the number concentration emissions were elevated during the second half of the heavy-duty federal test procedure when high speed was sustained. This information is relevant for the analysis of mechanisms by which <span class="hlt">particles</span> are emitted from field-aged DPFs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22382184','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22382184"><span id="translatedtitle">An iterative <span class="hlt">particle</span> <span class="hlt">filter</span> approach for coupled hydro-geophysical inversion of a controlled infiltration experiment</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Manoli, Gabriele; Rossi, Matteo; Pasetto, Damiano; Deiana, Rita; Ferraris, Stefano; Cassiani, Giorgio; Putti, Mario</p> <p>2015-02-15</p> <p>The modeling of unsaturated groundwater flow is affected by a high degree of uncertainty related to both measurement and model errors. Geophysical methods such as Electrical Resistivity Tomography (ERT) can provide useful indirect information on the hydrological processes occurring in the vadose zone. In this paper, we propose and test an iterated <span class="hlt">particle</span> <span class="hlt">filter</span> method to solve the coupled hydrogeophysical inverse problem. We focus on an infiltration test monitored by time-lapse ERT and modeled using Richards equation. The goal is to identify hydrological model parameters from ERT electrical potential measurements. Traditional uncoupled inversion relies on the solution of two sequential inverse problems, the first one applied to the ERT measurements, the second one to Richards equation. This approach does not ensure an accurate quantitative description of the physical state, typically violating mass balance. To avoid one of these two inversions and incorporate in the process more physical simulation constraints, we cast the problem within the framework of a SIR (Sequential Importance Resampling) data assimilation approach that uses a Richards equation solver to model the hydrological dynamics and a forward ERT simulator combined with Archie's law to serve as measurement model. ERT observations are then used to update the state of the system as well as to estimate the model parameters and their posterior distribution. The limitations of the traditional sequential Bayesian approach are investigated and an innovative iterative approach is proposed to estimate the model parameters with high accuracy. The numerical properties of the developed algorithm are verified on both homogeneous and heterogeneous synthetic test cases based on a real-world field experiment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JCoPh.283...37M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JCoPh.283...37M"><span id="translatedtitle">An iterative <span class="hlt">particle</span> <span class="hlt">filter</span> approach for coupled hydro-geophysical inversion of a controlled infiltration experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Manoli, Gabriele; Rossi, Matteo; Pasetto, Damiano; Deiana, Rita; Ferraris, Stefano; Cassiani, Giorgio; Putti, Mario</p> <p>2015-02-01</p> <p>The modeling of unsaturated groundwater flow is affected by a high degree of uncertainty related to both measurement and model errors. Geophysical methods such as Electrical Resistivity Tomography (ERT) can provide useful indirect information on the hydrological processes occurring in the vadose zone. In this paper, we propose and test an iterated <span class="hlt">particle</span> <span class="hlt">filter</span> method to solve the coupled hydrogeophysical inverse problem. We focus on an infiltration test monitored by time-lapse ERT and modeled using Richards equation. The goal is to identify hydrological model parameters from ERT electrical potential measurements. Traditional uncoupled inversion relies on the solution of two sequential inverse problems, the first one applied to the ERT measurements, the second one to Richards equation. This approach does not ensure an accurate quantitative description of the physical state, typically violating mass balance. To avoid one of these two inversions and incorporate in the process more physical simulation constraints, we cast the problem within the framework of a SIR (Sequential Importance Resampling) data assimilation approach that uses a Richards equation solver to model the hydrological dynamics and a forward ERT simulator combined with Archie's law to serve as measurement model. ERT observations are then used to update the state of the system as well as to estimate the model parameters and their posterior distribution. The limitations of the traditional sequential Bayesian approach are investigated and an innovative iterative approach is proposed to estimate the model parameters with high accuracy. The numerical properties of the developed algorithm are verified on both homogeneous and heterogeneous synthetic test cases based on a real-world field experiment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JMSTL...1..319N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JMSTL...1..319N"><span id="translatedtitle">Proposed Method for Estimating Traffic Accident Risk Factors Based on Object Tracking and Behavior Prediction Using <span class="hlt">Particle</span> <span class="hlt">Filtering</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Natori, Youichi; Kawamoto, Kazuhiko; Takahashi, Hiroshi; Hirota, Kaoru</p> <p></p> <p>A traffic accident prediction method using a priori knowledge based on accident data is proposed for safe driving support. Implementation is achieved by an algorithm using <span class="hlt">particle</span> <span class="hlt">filtering</span> and fuzzy inference to estimate accident risk factors. With this method, the distance between the host vehicle and a vehicle ahead and their relative velocity and relative acceleration are obtained from the results of <span class="hlt">particle</span> <span class="hlt">filtering</span> of driving data and are used as attributes to build the relative driving state space. The attributes are evaluated as likelihoods and then consolidated as a risk level using fuzzy inference. Experimental validation was done using videos of general driving situations obtained with an on-vehicle CCD camera and one simulated accident situation created based on the video data. The results show that high risk levels were calculated with the proposed method in the early stages of the accident situations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3791008','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3791008"><span id="translatedtitle">Globally <span class="hlt">Optimal</span> Multisensor Distributed Random Parameter Matrices Kalman <span class="hlt">Filtering</span> Fusion with Applications</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Luo, Yingting; Zhu, Yunmin; Luo, Dandan; Zhou, Jie; Song, Enbin; Wang, Donghua</p> <p>2008-01-01</p> <p>This paper proposes a new distributed Kalman <span class="hlt">filtering</span> fusion with random state transition and measurement matrices, i.e., random parameter matrices Kalman <span class="hlt">filtering</span>. It is proved that under a mild condition the fused state estimate is equivalent to the centralized Kalman <span class="hlt">filtering</span> using all sensor measurements; therefore, it achieves the best performance. More importantly, this result can be applied to Kalman <span class="hlt">filtering</span> with uncertain observations including the measurement with a false alarm probability as a special case, as well as, randomly variant dynamic systems with multiple models. Numerical examples are given which support our analysis and show significant performance loss of ignoring the randomness of the parameter matrices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25945859','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25945859"><span id="translatedtitle"><span class="hlt">Particle</span> removal in a novel sequential mechanical <span class="hlt">filter</span> system loaded with blackwater.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Todt, Daniel; Jenssen, Petter D</p> <p>2015-01-01</p> <p>A novel sequential mechanical <span class="hlt">filter</span> system was developed as an alternative primary treatment method for onsite wastewater treatment. The <span class="hlt">filter</span> combines traditional screening with a novel type of counter-flow <span class="hlt">filter</span> using wood-shavings as a biodegradable <span class="hlt">filter</span> matrix. This study tested the system in a batch loading regime simulating high frequency toilet flushing using blackwater from a student dormitory. The <span class="hlt">filter</span> removed 78-85% of suspended solids, 60-80% of chemical oxygen demand, and 42-57% of total-P in blackwater, giving a retentate with a dry matter content of 13-20%. Data analysis clearly indicated a tendency towards higher removal performance with high inlet concentrations, hence, the system seems to be most applicable to blackwater or other types of wastewater with a high content of suspended solids. PMID:25945859</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/973636','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/973636"><span id="translatedtitle">Toward an <span class="hlt">Optimal</span> Position for IVC <span class="hlt">Filters</span>: Computational Modeling of the Impact of Renal Vein Inflow</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wang, S L; Singer, M A</p> <p>2009-07-13</p> <p>The purpose of this report is to evaluate the hemodynamic effects of renal vein inflow and <span class="hlt">filter</span> position on unoccluded and partially occluded IVC <span class="hlt">filters</span> using three-dimensional computational fluid dynamics. Three-dimensional models of the TrapEase and Gunther Celect IVC <span class="hlt">filters</span>, spherical thrombi, and an IVC with renal veins were constructed. Hemodynamics of steady-state flow was examined for unoccluded and partially occluded TrapEase and Gunther Celect IVC <span class="hlt">filters</span> in varying proximity to the renal veins. Flow past the unoccluded <span class="hlt">filters</span> demonstrated minimal disruption. Natural regions of stagnant/recirculating flow in the IVC are observed superior to the bilateral renal vein inflows, and high flow velocities and elevated shear stresses are observed in the vicinity of renal inflow. Spherical thrombi induce stagnant and/or recirculating flow downstream of the thrombus. Placement of the TrapEase <span class="hlt">filter</span> in the suprarenal vein position resulted in a large area of low shear stress/stagnant flow within the <span class="hlt">filter</span> just downstream of thrombus trapped in the upstream trapping position. <span class="hlt">Filter</span> position with respect to renal vein inflow influences the hemodynamics of <span class="hlt">filter</span> trapping. Placement of the TrapEase <span class="hlt">filter</span> in a suprarenal location may be thrombogenic with redundant areas of stagnant/recirculating flow and low shear stress along the caval wall due to the upstream trapping position and the naturally occurring region of stagnant flow from the renal veins. Infrarenal vein placement of IVC <span class="hlt">filters</span> in a near juxtarenal position with the downstream cone near the renal vein inflow likely confers increased levels of mechanical lysis of trapped thrombi due to increased shear stress from renal vein inflow.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23664450','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23664450"><span id="translatedtitle">Global localization of 3D anatomical structures by pre-<span class="hlt">filtered</span> Hough forests and discrete <span class="hlt">optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Donner, René; Menze, Bjoern H; Bischof, Horst; Langs, Georg</p> <p>2013-12-01</p> <p>The accurate localization of anatomical landmarks is a challenging task, often solved by domain specific approaches. We propose a method for the automatic localization of landmarks in complex, repetitive anatomical structures. The key idea is to combine three steps: (1) a classifier for pre-<span class="hlt">filtering</span> anatomical landmark positions that (2) are refined through a Hough regression model, together with (3) a parts-based model of the global landmark topology to select the final landmark positions. During training landmarks are annotated in a set of example volumes. A classifier learns local landmark appearance, and Hough regressors are trained to aggregate neighborhood information to a precise landmark coordinate position. A non-parametric geometric model encodes the spatial relationships between the landmarks and derives a topology which connects mutually predictive landmarks. During the global search we classify all voxels in the query volume, and perform regression-based agglomeration of landmark probabilities to highly accurate and specific candidate points at potential landmark locations. We encode the candidates' weights together with the conformity of the connecting edges to the learnt geometric model in a Markov Random Field (MRF). By solving the corresponding discrete <span class="hlt">optimization</span> problem, the most probable location for each model landmark is found in the query volume. We show that this approach is able to consistently localize the model landmarks despite the complex and repetitive character of the anatomical structures on three challenging data sets (hand radiographs, hand CTs, and whole body CTs), with a median localization error of 0.80 mm, 1.19 mm and 2.71 mm, respectively. PMID:23664450</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014CNSNS..19..914C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014CNSNS..19..914C"><span id="translatedtitle">Tribal <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> for neurofuzzy inference systems and its prediction applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Cheng-Hung; Liao, Yen-Yun</p> <p>2014-04-01</p> <p>This study presents tribal <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (TPSO) to <span class="hlt">optimize</span> the parameters of the functional-link-based neurofuzzy inference system (FLNIS) for prediction applications. The proposed TPSO uses <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO) as evolution strategies of the tribes <span class="hlt">optimization</span> algorithm (TOA) to balance local and global exploration of the search space. The proposed TPSO uses a self-clustering algorithm to divide the <span class="hlt">particle</span> swarm into multiple tribes, and selects suitable evolution strategies to update each <span class="hlt">particle</span>. The TPSO also uses a tribal adaptation mechanism to remove and generate <span class="hlt">particles</span> and reconstruct tribal links. The tribal adaptation mechanism can improve the qualities of the tribe and the tribe adaptation. Finally, the FLNIS model with the proposed TPSO (FLNIS-TPSO) was used in several predictive applications. Experimental results demonstrated that the proposed TPSO method converges quickly and yields a lower RMS error than other current methods.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1076691','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1076691"><span id="translatedtitle">STEPS: A Grid Search Methodology for <span class="hlt">Optimized</span> Peptide Identification <span class="hlt">Filtering</span> of MS/MS Database Search Results</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Piehowski, Paul D.; Petyuk, Vladislav A.; Sandoval, John D.; Burnum, Kristin E.; Kiebel, Gary R.; Monroe, Matthew E.; Anderson, Gordon A.; Camp, David G.; Smith, Richard D.</p> <p>2013-03-01</p> <p>For bottom-up proteomics there are a wide variety of database searching algorithms in use for matching peptide sequences to tandem MS spectra. Likewise, there are numerous strategies being employed to produce a confident list of peptide identifications from the different search algorithm outputs. Here we introduce a grid search approach for determining <span class="hlt">optimal</span> database <span class="hlt">filtering</span> criteria in shotgun proteomics data analyses that is easily adaptable to any search. Systematic Trial and Error Parameter Selection - referred to as STEPS - utilizes user-defined parameter ranges to test a wide array of parameter combinations to arrive at an <span class="hlt">optimal</span> "parameter set" for data <span class="hlt">filtering</span>, thus maximizing confident identifications. The benefits of this approach in terms of numbers of true positive identifications are demonstrated using datasets derived from immunoaffinity-depleted blood serum and a bacterial cell lysate, two common proteomics sample types.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21032835','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21032835"><span id="translatedtitle">Dual-energy approach to contrast-enhanced mammography using the balanced <span class="hlt">filter</span> method: Spectral <span class="hlt">optimization</span> and preliminary phantom measurement</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Saito, Masatoshi</p> <p>2007-11-15</p> <p>Dual-energy contrast agent-enhanced mammography is a technique of demonstrating breast cancers obscured by a cluttered background resulting from the contrast between soft tissues in the breast. The technique has usually been implemented by exploiting two exposures to different x-ray tube voltages. In this article, another dual-energy approach using the balanced <span class="hlt">filter</span> method without switching the tube voltages is described. For the spectral <span class="hlt">optimization</span> of dual-energy mammography using the balanced <span class="hlt">filters</span>, we applied a theoretical framework reported by Lemacks et al. [Med. Phys. 29, 1739-1751 (2002)] to calculate the signal-to-noise ratio (SNR) in an iodinated contrast agent subtraction image. This permits the selection of beam parameters such as tube voltage and balanced <span class="hlt">filter</span> material, and the <span class="hlt">optimization</span> of the latter's thickness with respect to some critical quantity--in this case, mean glandular dose. For an imaging system with a 0.1 mm thick CsI:Tl scintillator, we predict that the <span class="hlt">optimal</span> tube voltage would be 45 kVp for a tungsten anode using zirconium, iodine, and neodymium balanced <span class="hlt">filters</span>. A mean glandular dose of 1.0 mGy is required to obtain an SNR of 5 in order to detect 1.0 mg/cm{sup 2} iodine in the resulting clutter-free image of a 5 cm thick breast composed of 50% adipose and 50% glandular tissue. In addition to spectral <span class="hlt">optimization</span>, we carried out phantom measurements to demonstrate the present dual-energy approach for obtaining a clutter-free image, which preferentially shows iodine, of a breast phantom comprising three major components - acrylic spheres, olive oil, and an iodinated contrast agent. The detection of iodine details on the cluttered background originating from the contrast between acrylic spheres and olive oil is analogous to the task of distinguishing contrast agents in a mixture of glandular and adipose tissues.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ApPhL.103i3702I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ApPhL.103i3702I"><span id="translatedtitle">Focusing time harmonic scalar fields in non-homogenous lossy media: Inverse <span class="hlt">filter</span> vs. constrained power focusing <span class="hlt">optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Iero, D. A. M.; Isernia, T.; Crocco, L.</p> <p>2013-08-01</p> <p>Two strategies to focus time harmonic scalar fields in known inhomogeneous lossy media are compared. The first one is the Inverse <span class="hlt">Filter</span> (IF) method, which faces the focusing task as the synthesis of a nominal field. The second one is the Constrained Power Focusing <span class="hlt">Optimization</span> (CPFO) method, which tackles the problem in terms of constrained mask constrained power <span class="hlt">optimization</span>. Numerical examples representative of focusing in noninvasive microwave hyperthermia are provided to show that CPFO is able to outperform IF, thanks to the additional degrees of freedom arising from the adopted power synthesis formulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4180414','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4180414"><span id="translatedtitle">Using Animal Instincts to Design Efficient Biomedical Studies via <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Qiu, Jiaheng; Chen, Ray-Bing; Wang, Weichung; Wong, Weng Kee</p> <p>2014-01-01</p> <p><span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> (PSO) is an increasingly popular metaheuristic algorithm for solving complex <span class="hlt">optimization</span> problems. Its popularity is due to its repeated successes in finding an optimum or a near <span class="hlt">optimal</span> solution for problems in many applied disciplines. The algorithm makes no assumption of the function to be <span class="hlt">optimized</span> and for biomedical experiments like those presented here, PSO typically finds the <span class="hlt">optimal</span> solutions in a few seconds of CPU time on a garden-variety laptop. We apply PSO to find various types of <span class="hlt">optimal</span> designs for several problems in the biological sciences and compare PSO performance relative to the differential evolution algorithm, another popular metaheuristic algorithm in the engineering literature. PMID:25285268</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25285268','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25285268"><span id="translatedtitle">Using Animal Instincts to Design Efficient Biomedical Studies via <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Qiu, Jiaheng; Chen, Ray-Bing; Wang, Weichung; Wong, Weng Kee</p> <p>2014-10-01</p> <p><span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> (PSO) is an increasingly popular metaheuristic algorithm for solving complex <span class="hlt">optimization</span> problems. Its popularity is due to its repeated successes in finding an optimum or a near <span class="hlt">optimal</span> solution for problems in many applied disciplines. The algorithm makes no assumption of the function to be <span class="hlt">optimized</span> and for biomedical experiments like those presented here, PSO typically finds the <span class="hlt">optimal</span> solutions in a few seconds of CPU time on a garden-variety laptop. We apply PSO to find various types of <span class="hlt">optimal</span> designs for several problems in the biological sciences and compare PSO performance relative to the differential evolution algorithm, another popular metaheuristic algorithm in the engineering literature. PMID:25285268</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4359813','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4359813"><span id="translatedtitle"><span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> Algorithm for <span class="hlt">Optimizing</span> Assignment of Blood in Blood Banking System</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Olusanya, Micheal O.; Arasomwan, Martins A.; Adewumi, Aderemi O.</p> <p>2015-01-01</p> <p>This paper reports the performance of <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO) for the assignment of blood to meet patients' blood transfusion requests for blood transfusion. While the drive for blood donation lingers, there is need for effective and efficient management of available blood in blood banking systems. Moreover, inherent danger of transfusing wrong blood types to patients, unnecessary importation of blood units from external sources, and wastage of blood products due to nonusage necessitate the development of mathematical models and techniques for effective handling of blood distribution among available blood types in order to minimize wastages and importation from external sources. This gives rise to the blood assignment problem (BAP) introduced recently in literature. We propose a queue and multiple knapsack models with PSO-based solution to address this challenge. Simulation is based on sets of randomly generated data that mimic real-world population distribution of blood types. Results obtained show the efficiency of the proposed algorithm for BAP with no blood units wasted and very low importation, where necessary, from outside the blood bank. The result therefore can serve as a benchmark and basis for decision support tools for real-life deployment. PMID:25815046</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4121098','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4121098"><span id="translatedtitle">Stochastic <span class="hlt">Optimized</span> Relevance Feedback <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> for Content Based Image Retrieval</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hashim, Rathiah; Noor Elaiza, Abd Khalid; Irtaza, Aun</p> <p>2014-01-01</p> <p>One of the major challenges for the CBIR is to bridge the gap between low level features and high level semantics according to the need of the user. To overcome this gap, relevance feedback (RF) coupled with support vector machine (SVM) has been applied successfully. However, when the feedback sample is small, the performance of the SVM based RF is often poor. To improve the performance of RF, this paper has proposed a new technique, namely, PSO-SVM-RF, which combines SVM based RF with <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO). The aims of this proposed technique are to enhance the performance of SVM based RF and also to minimize the user interaction with the system by minimizing the RF number. The PSO-SVM-RF was tested on the coral photo gallery containing 10908 images. The results obtained from the experiments showed that the proposed PSO-SVM-RF achieved 100% accuracy in 8 feedback iterations for top 10 retrievals and 80% accuracy in 6 iterations for 100 top retrievals. This implies that with PSO-SVM-RF technique high accuracy rate is achieved at a small number of iterations. PMID:25121136</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhyA..416..157L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhyA..416..157L"><span id="translatedtitle">Evacuation dynamic and exit <span class="hlt">optimization</span> of a supermarket based on <span class="hlt">particle</span> swarm <span class="hlt">optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Lin; Yu, Zhonghai; Chen, Yang</p> <p>2014-12-01</p> <p>A modified <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> algorithm is proposed in this paper to investigate the dynamic of pedestrian evacuation from a fire in a public building-a supermarket with multiple exits and configurations of counters. Two distinctive evacuation behaviours featured by the shortest-path strategy and the following-up strategy are simulated in the model, accounting for different categories of age and sex of the pedestrians along with the impact of the fire, including gases, heat and smoke. To examine the relationship among the progress of the overall evacuation and the layout and configuration of the site, a series of simulations are conducted in various settings: without a fire and with a fire at different locations. Those experiments reveal a general pattern of two-phase evacuation, i.e., a steep section and a flat section, in addition to the impact of the presence of multiple exits on the evacuation along with the geographic locations of the exits. For the study site, our simulations indicated the deficiency of the configuration and the current layout of this site in the process of evacuation and verified the availability of proposed solutions to resolve the deficiency. More specifically, for improvement of the effectiveness of the evacuation from the site, adding an exit between Exit 6 and Exit 7 and expanding the corridor at the right side of Exit 7 would significantly reduce the evacuation time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25815046','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25815046"><span id="translatedtitle"><span class="hlt">Particle</span> swarm <span class="hlt">optimization</span> algorithm for <span class="hlt">optimizing</span> assignment of blood in blood banking system.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Olusanya, Micheal O; Arasomwan, Martins A; Adewumi, Aderemi O</p> <p>2015-01-01</p> <p>This paper reports the performance of <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO) for the assignment of blood to meet patients' blood transfusion requests for blood transfusion. While the drive for blood donation lingers, there is need for effective and efficient management of available blood in blood banking systems. Moreover, inherent danger of transfusing wrong blood types to patients, unnecessary importation of blood units from external sources, and wastage of blood products due to nonusage necessitate the development of mathematical models and techniques for effective handling of blood distribution among available blood types in order to minimize wastages and importation from external sources. This gives rise to the blood assignment problem (BAP) introduced recently in literature. We propose a queue and multiple knapsack models with PSO-based solution to address this challenge. Simulation is based on sets of randomly generated data that mimic real-world population distribution of blood types. Results obtained show the efficiency of the proposed algorithm for BAP with no blood units wasted and very low importation, where necessary, from outside the blood bank. The result therefore can serve as a benchmark and basis for decision support tools for real-life deployment. PMID:25815046</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25121136','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25121136"><span id="translatedtitle">Stochastic <span class="hlt">optimized</span> relevance feedback <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> for content based image retrieval.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Imran, Muhammad; Hashim, Rathiah; Noor Elaiza, Abd Khalid; Irtaza, Aun</p> <p>2014-01-01</p> <p>One of the major challenges for the CBIR is to bridge the gap between low level features and high level semantics according to the need of the user. To overcome this gap, relevance feedback (RF) coupled with support vector machine (SVM) has been applied successfully. However, when the feedback sample is small, the performance of the SVM based RF is often poor. To improve the performance of RF, this paper has proposed a new technique, namely, PSO-SVM-RF, which combines SVM based RF with <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO). The aims of this proposed technique are to enhance the performance of SVM based RF and also to minimize the user interaction with the system by minimizing the RF number. The PSO-SVM-RF was tested on the coral photo gallery containing 10908 images. The results obtained from the experiments showed that the proposed PSO-SVM-RF achieved 100% accuracy in 8 feedback iterations for top 10 retrievals and 80% accuracy in 6 iterations for 100 top retrievals. This implies that with PSO-SVM-RF technique high accuracy rate is achieved at a small number of iterations. PMID:25121136</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MS%26E..114a2055I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MS%26E..114a2055I"><span id="translatedtitle">Performance evaluation of different types of <span class="hlt">particle</span> representation procedures of <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> in Job-shop Scheduling Problems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Izah Anuar, Nurul; Saptari, Adi</p> <p>2016-02-01</p> <p>This paper addresses the types of <span class="hlt">particle</span> representation (encoding) procedures in a population-based stochastic <span class="hlt">optimization</span> technique in solving scheduling problems known in the job-shop manufacturing environment. It intends to evaluate and compare the performance of different <span class="hlt">particle</span> representation procedures in <span class="hlt">Particle</span> Swarm <span class="hlt">Optimization</span> (PSO) in the case of solving Job-shop Scheduling Problems (JSP). <span class="hlt">Particle</span> representation procedures refer to the mapping between the <span class="hlt">particle</span> position in PSO and the scheduling solution in JSP. It is an important step to be carried out so that each <span class="hlt">particle</span> in PSO can represent a schedule in JSP. Three procedures such as Operation and <span class="hlt">Particle</span> Position Sequence (OPPS), random keys representation and random-key encoding scheme are used in this study. These procedures have been tested on FT06 and FT10 benchmark problems available in the OR-Library, where the objective function is to minimize the makespan by the use of MATLAB software. Based on the experimental results, it is discovered that OPPS gives the best performance in solving both benchmark problems. The contribution of this paper is the fact that it demonstrates to the practitioners involved in complex scheduling problems that different <span class="hlt">particle</span> representation procedures can have significant effects on the performance of PSO in solving JSP.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005PMB....50.5509C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005PMB....50.5509C"><span id="translatedtitle"><span class="hlt">Optimal</span> <span class="hlt">filter</span> design for shielded and unshielded ambient noise reduction in fetal magnetocardiography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Comani, S.; Mantini, D.; Alleva, G.; Di Luzio, S.; Romani, G. L.</p> <p>2005-12-01</p> <p>The greatest impediment to extracting high-quality fetal signals from fetal magnetocardiography (fMCG) is environmental magnetic noise, which may have peak-to-peak intensity comparable to fetal QRS amplitude. Being an unstructured Gaussian signal with large disturbances at specific frequencies, ambient field noise can be reduced with hardware-based approaches and/or with software algorithms that digitally <span class="hlt">filter</span> magnetocardiographic recordings. At present, no systematic evaluation of <span class="hlt">filters</span>' performances on shielded and unshielded fMCG is available. We designed high-pass and low-pass Chebychev II-type <span class="hlt">filters</span> with zero-phase and stable impulse response; the most commonly used band-pass <span class="hlt">filters</span> were implemented combining high-pass and low-pass <span class="hlt">filters</span>. The achieved ambient noise reduction in shielded and unshielded recordings was quantified, and the corresponding signal-to-noise ratio (SNR) and signal-to-distortion ratio (SDR) of the retrieved fetal signals was evaluated. The study regarded 66 fMCG datasets at different gestational ages (22-37 weeks). Since the spectral structures of shielded and unshielded magnetic noise were very similar, we concluded that the same <span class="hlt">filter</span> setting might be applied to both conditions. Band-pass <span class="hlt">filters</span> (1.0-100 Hz) and (2.0-100 Hz) provided the best combinations of fetal signal detection rates, SNR and SDR; however, the former should be preferred in the case of arrhythmic fetuses, which might present spectral components below 2 Hz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/387286','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/387286"><span id="translatedtitle">A comparison of biologically active <span class="hlt">filters</span> for the removal of ozone by-products, turbidity, and <span class="hlt">particles</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Coffey, B.M.; Krasner, S.W.; Sclimenti, M.J.; Hacker, P.A.; Gramith, J.T.</p> <p>1996-11-01</p> <p>Biofiltration tests were performed at the Metropolitan Water District of Southern California`s 5.5-mgd (21,000 m{sup 3}d) demonstration plant using two 400 ft{sup 2} (37 m{sup 2}) anthracite/sand <span class="hlt">filters</span> and a 6 ft{sup 2} (0.56 m{sup 2}) granular activated carbon (GAC)/sand <span class="hlt">filter</span> operated in parallel. The empty-bed contact time (EBCT) within the GAC and anthracite ranged from 2.1-3.1 min. The <span class="hlt">filters</span> were evaluated based on (1) conventional filtration performance (turbidity, <span class="hlt">particle</span> removal, and headloss); (2) removal of biodegradable ozone by-products (assimilable organic carbon [AOC], aldehydes, and aldoketoacids) after startup; (3) removal of biodegradable ozone by-products at steady state; and (4) resistance to short-term process upsets such as intermittent chlorination or <span class="hlt">filter</span> out-of-service time. Approximately 80 percent formaldehyde removal was achieved by the anthracite/sand <span class="hlt">filter</span> operated at a 2.1-min EBCT (6 gpm/ft{sup 2} [15 m/h]) within 8 days of ozone operation. The GAC/sand <span class="hlt">filter</span> operated at the same rate achieved 80 percent removal within 1 day, possibly as an additive effect of adsorption and biological removal. In-depth aldehyde monitoring at four depths (0.5-min EBCT intervals) provided additional insight into the removal kinetics. During periods of warmer water temperature, from 20 to 48 percent of the AOC was removed in the flocculation/sedimentation basins by 40-75 percent. This percentage removal typically resulted in AOC concentrations within 40 {mu}g C/L of the raw, unozonated water levels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9387E..0OG','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9387E..0OG"><span id="translatedtitle">Three dimensional indoor positioning based on visible light with Gaussian mixture sigma-point <span class="hlt">particle</span> <span class="hlt">filter</span> technique</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gu, Wenjun; Zhang, Weizhi; Wang, Jin; Amini Kashani, M. R.; Kavehrad, Mohsen</p> <p>2015-01-01</p> <p>Over the past decade, location based services (LBS) have found their wide applications in indoor environments, such as large shopping malls, hospitals, warehouses, airports, etc. Current technologies provide wide choices of available solutions, which include Radio-frequency identification (RFID), Ultra wideband (UWB), wireless local area network (WLAN) and Bluetooth. With the rapid development of light-emitting-diodes (LED) technology, visible light communications (VLC) also bring a practical approach to LBS. As visible light has a better immunity against multipath effect than radio waves, higher positioning accuracy is achieved. LEDs are utilized both for illumination and positioning purpose to realize relatively lower infrastructure cost. In this paper, an indoor positioning system using VLC is proposed, with LEDs as transmitters and photo diodes as receivers. The algorithm for estimation is based on received-signalstrength (RSS) information collected from photo diodes and trilateration technique. By appropriately making use of the characteristics of receiver movements and the property of trilateration, estimation on three-dimensional (3-D) coordinates is attained. <span class="hlt">Filtering</span> technique is applied to enable tracking capability of the algorithm, and a higher accuracy is reached compare to raw estimates. Gaussian mixture Sigma-point <span class="hlt">particle</span> <span class="hlt">filter</span> (GM-SPPF) is proposed for this 3-D system, which introduces the notion of Gaussian Mixture Model (GMM). The number of <span class="hlt">particles</span> in the <span class="hlt">filter</span> is reduced by approximating the probability distribution with Gaussian components.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24527647','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24527647"><span id="translatedtitle">Preliminary study on filamentous <span class="hlt">particle</span> distribution in septic tank effluent and their impact on <span class="hlt">filter</span> cake development.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Spychała, Marcin; Nieć, Jakub; Pawlak, Maciej</p> <p>2013-01-01</p> <p>In this paper, the preliminary study on the impact of filamentous <span class="hlt">particles</span> (FP) in the septic tank effluent (STE) on <span class="hlt">filter</span> cake (FC) development was presented. The number, length and diameter (30 p./cm3, 451 and 121 microm, respectively, on average) of FPs were measured using microscope image analysis of STE samples condensed using a vacuum evaporation set. Results of this study showed, that 0.73% of volatile suspended solids (VSSs) mass from the STE occurs in the form of FPs. No correlation between FP total mass and VSS was found. An experiment with a layer of FPs simulated by ground toilet paper was conducted and showed the impact of this layer (4.89 mg/cm2) on wastewater hydraulic conductivity--for an FC with FPs (FC-FP), hydraulic conductivity was seven times lower than for the FC without the FP layer, and on outflow quality (lower concentration of organic matter expressed as chemical oxygen demand (COD) in effluent from the FC-FP <span class="hlt">filter</span> than in the effluent from the FC <span class="hlt">filter</span>: 618 and 732 gO2/m3, respectively). Despite a relatively small amount of FPs in STE solids (as volume fraction), they play an important role in FC development due to their relatively high length and low degradability. Probably relatively small pores of the FC containing FPs (FC-FP) caused a small <span class="hlt">particle</span> blocking and a decrease in permeability. PMID:24527647</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007SPIE.6789E..22W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007SPIE.6789E..22W"><span id="translatedtitle"><span class="hlt">Optimal</span> features selection based on circular Gabor <span class="hlt">filters</span> and RSE in texture segmentation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Qiong; Liu, Jian; Tian, Jinwen</p> <p>2007-12-01</p> <p>This paper designs the circular Gabor <span class="hlt">filters</span> incorporating into the human visual characteristics, and the concept of mutual information entropy in rough set is introduced to evaluate the effect of the features extracted from different <span class="hlt">filters</span> on clustering, redundant features are got rid of, Experimental results indicate that the proposed algorithm outperforms conventional approaches in terms of both objective measurements and visual evaluation in texture segmentation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4818102','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4818102"><span id="translatedtitle">Robust Brain-Machine Interface Design Using <span class="hlt">Optimal</span> Feedback Control Modeling and Adaptive Point Process <span class="hlt">Filtering</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Carmena, Jose M.</p> <p>2016-01-01</p> <p>Much progress has been made in brain-machine interfaces (BMI) using decoders such as Kalman <span class="hlt">filters</span> and finding their parameters with closed-loop decoder adaptation (CLDA). However, current decoders do not model the spikes directly, and hence may limit the processing time-scale of BMI control and adaptation. Moreover, while specialized CLDA techniques for intention estimation and assisted training exist, a unified and systematic CLDA framework that generalizes across different setups is lacking. Here we develop a novel closed-loop BMI training architecture that allows for processing, control, and adaptation using spike events, enables robust control and extends to various tasks. Moreover, we develop a unified control-theoretic CLDA framework within which intention estimation, assisted training, and adaptation are performed. The architecture incorporates an infinite-horizon <span class="hlt">optimal</span> feedback-control (OFC) model of the brain’s behavior in closed-loop BMI control, and a point process model of spikes. The OFC model infers the user’s motor intention during CLDA—a process termed intention estimation. OFC is also used to design an autonomous and dynamic assisted training technique. The point process model allows for neural processing, control and decoder adaptation with every spike event and at a faster time-scale than current decoders; it also enables dynamic spike-event-based parameter adaptation unlike current CLDA methods that use batch-based adaptation on much slower adaptation time-scales. We conducted closed-loop experiments in a non-human primate over tens of days to dissociate the effects of these novel CLDA components. The OFC intention estimation improved BMI performance compared with current intention estimation techniques. OFC assisted training allowed the subject to consistently achieve proficient control. Spike-event-based adaptation resulted in faster and more consistent performance convergence compared with batch-based methods, and was robust to parameter initialization. Finally, the architecture extended control to tasks beyond those used for CLDA training. These results have significant implications towards the development of clinically-viable neuroprosthetics. PMID:27035820</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27035820','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27035820"><span id="translatedtitle">Robust Brain-Machine Interface Design Using <span class="hlt">Optimal</span> Feedback Control Modeling and Adaptive Point Process <span class="hlt">Filtering</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shanechi, Maryam M; Orsborn, Amy L; Carmena, Jose M</p> <p>2016-04-01</p> <p>Much progress has been made in brain-machine interfaces (BMI) using decoders such as Kalman <span class="hlt">filters</span> and finding their parameters with closed-loop decoder adaptation (CLDA). However, current decoders do not model the spikes directly, and hence may limit the processing time-scale of BMI control and adaptation. Moreover, while specialized CLDA techniques for intention estimation and assisted training exist, a unified and systematic CLDA framework that generalizes across different setups is lacking. Here we develop a novel closed-loop BMI training architecture that allows for processing, control, and adaptation using spike events, enables robust control and extends to various tasks. Moreover, we develop a unified control-theoretic CLDA framework within which intention estimation, assisted training, and adaptation are performed. The architecture incorporates an infinite-horizon <span class="hlt">optimal</span> feedback-control (OFC) model of the brain's behavior in closed-loop BMI control, and a point process model of spikes. The OFC model infers the user's motor intention during CLDA-a process termed intention estimation. OFC is also used to design an autonomous and dynamic assisted training technique. The point process model allows for neural processing, control and decoder adaptation with every spike event and at a faster time-scale than current decoders; it also enables dynamic spike-event-based parameter adaptation unlike current CLDA methods that use batch-based adaptation on much slower adaptation time-scales. We conducted closed-loop experiments in a non-human primate over tens of days to dissociate the effects of these novel CLDA components. The OFC intention estimation improved BMI performance compared with current intention estimation techniques. OFC assisted training allowed the subject to consistently achieve proficient control. Spike-event-based adaptation resulted in faster and more consistent performance convergence compared with batch-based methods, and was robust to parameter initialization. Finally, the architecture extended control to tasks beyond those used for CLDA training. These results have significant implications towards the development of clinically-viable neuroprosthetics. PMID:27035820</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=131206&keyword=kong&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=58233451&CFTOKEN=66746762','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=131206&keyword=kong&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=58233451&CFTOKEN=66746762"><span id="translatedtitle">MODELING REFLECTANCE AND TRANSMITTANCE OF QUARTZ-FIBER <span class="hlt">FILTER</span> SAMPLES CONTAINING ELEMENTAL CARBON <span class="hlt">PARTICLES</span>: IMPLICATIONS FOR THERMAL/OPTICAL ANALYSIS. (R831086)</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p><p>A radiative transfer scheme that considers absorption, scattering, and distribution of light-absorbing elemental carbon (EC) <span class="hlt">particles</span> collected on a quartz-fiber <span class="hlt">filter</span> was developed to explain simultaneous <span class="hlt">filter</span> reflectance and transmittance observations prior to and during...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H13F1182S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H13F1182S"><span id="translatedtitle">Pareto <span class="hlt">optimal</span> calibration of highly nonlinear reactive transport groundwater models using <span class="hlt">particle</span> swarm <span class="hlt">optimization</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Siade, A. J.; Prommer, H.; Welter, D.</p> <p>2014-12-01</p> <p>Groundwater management and remediation requires the implementation of numerical models in order to evaluate the potential anthropogenic impacts on aquifer systems. In many situations, the numerical model must, not only be able to simulate groundwater flow and transport, but also geochemical and biological processes. Each process being simulated carries with it a set of parameters that must be identified, along with differing potential sources of model-structure error. Various data types are often collected in the field and then used to calibrate the numerical model; however, these data types can represent very different processes and can subsequently be sensitive to the model parameters in extremely complex ways. Therefore, developing an appropriate weighting strategy to address the contributions of each data type to the overall least-squares objective function is not straightforward. This is further compounded by the presence of potential sources of model-structure errors that manifest themselves differently for each observation data type. Finally, reactive transport models are highly nonlinear, which can lead to convergence failure for algorithms operating on the assumption of local linearity. In this study, we propose a variation of the popular, <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> algorithm to address trade-offs associated with the calibration of one data type over another. This method removes the need to specify weights between observation groups and instead, produces a multi-dimensional Pareto front that illustrates the trade-offs between data types. We use the PEST++ run manager, along with the standard PEST input/output structure, to implement parallel programming across multiple desktop computers using TCP/IP communications. This allows for very large swarms of <span class="hlt">particles</span> without the need of a supercomputing facility. The method was applied to a case study in which modeling was used to gain insight into the mobilization of arsenic at a deepwell injection site. Multiple data types (e.g., hydrochemical, geophysical, tracer, temperature, etc.) were collected prior to, and during an injection trial. Visualizing the trade-off between the calibration of each data type has provided the means of identifying some model-structure deficiencies.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020035545&hterms=particles+lead&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dparticles%2Blead','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020035545&hterms=particles+lead&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dparticles%2Blead"><span id="translatedtitle"><span class="hlt">Optimization</span> of Time-Dependent <span class="hlt">Particle</span> Tracing Using Tetrahedral Decomposition</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kenwright, David; Lane, David</p> <p>1995-01-01</p> <p>An efficient algorithm is presented for computing <span class="hlt">particle</span> paths, streak lines and time lines in time-dependent flows with moving curvilinear grids. The integration, velocity interpolation and step-size control are all performed in physical space which avoids the need to transform the velocity field into computational space. This leads to higher accuracy because there are no Jacobian matrix approximations or expensive matrix inversions. Integration accuracy is maintained using an adaptive step-size control scheme which is regulated by the path line curvature. The problem of cell-searching, point location and interpolation in physical space is simplified by decomposing hexahedral cells into tetrahedral cells. This enables the point location to be done analytically and substantially faster than with a Newton-Raphson iterative method. Results presented show this algorithm is up to six times faster than <span class="hlt">particle</span> tracers which operate on hexahedral cells yet produces almost identical <span class="hlt">particle</span> trajectories.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012APS..DPPUP8008R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012APS..DPPUP8008R"><span id="translatedtitle">Programmable physical parameter <span class="hlt">optimization</span> for <span class="hlt">particle</span> plasma simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ragan-Kelley, Benjamin; Verboncoeur, John; Lin, Ming-Chieh</p> <p>2012-10-01</p> <p>We have developed a scheme for interactive and programmable <span class="hlt">optimization</span> of physical parameters for plasma simulations. The simulation code Object-Oriented Plasma Device 1-D (OOPD1) has been adapted to a Python interface, allowing sophisticated user or program interaction with simulations, and detailed numerical analysis via numpy. Because the analysis/diagnostic interface is the same as the input mechanism (the Python programming language), it is straightforward to <span class="hlt">optimize</span> simulation parameters based on analysis of previous runs and automate the <span class="hlt">optimization</span> process using a user-determined scheme and criteria. An example use case of the Child-Langmuir space charge limit in bipolar flow is demonstrated, where the beam current is iterated upon by measuring the relationship of the measured current and the injected current.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014HMT....50.1375G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014HMT....50.1375G"><span id="translatedtitle">Thermal-economic multi-objective <span class="hlt">optimization</span> of shell and tube heat exchanger using <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ghanei, A.; Assareh, E.; Biglari, M.; Ghanbarzadeh, A.; Noghrehabadi, A. R.</p> <p>2014-10-01</p> <p>Many studies are performed by researchers about shell and tube heat exchanger (STHE) but the multi-objective <span class="hlt">particle</span> swarm <span class="hlt">optimization</span> (PSO) technique has never been used in such studies. This paper presents application of thermal-economic multi-objective <span class="hlt">optimization</span> of STHE using PSO. For <span class="hlt">optimal</span> design of a STHE, it was first thermally modeled using e-number of transfer units method while Bell-Delaware procedure was applied to estimate its shell side heat transfer coefficient and pressure drop. Multi objective PSO (MOPSO) method was applied to obtain the maximum effectiveness (heat recovery) and the minimum total cost as two objective functions. The results of <span class="hlt">optimal</span> designs were a set of multiple optimum solutions, called `Pareto <span class="hlt">optimal</span> solutions'. In order to show the accuracy of the algorithm, a comparison is made with the non-dominated sorting genetic algorithm (NSGA-II) and MOPSO which are developed for the same problem.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvE..92f2830I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvE..92f2830I"><span id="translatedtitle">Flow instability originating from <span class="hlt">particle</span> configurations using the two-dimensional <span class="hlt">optimal</span> velocity model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ishiwata, Ryosuke; Sugiyama, Yuki</p> <p>2015-12-01</p> <p>The two-dimensional <span class="hlt">optimal</span> velocity model has potential applications to pedestrian dynamics and the collective motion of animals. In this paper, we extend the linear stability analysis presented in a previous paper [A Nakayama et al., Phys. Rev. E. 77, 016105 (2008), 10.1103/PhysRevE.77.016105] and investigate the effects of <span class="hlt">particle</span> configuration on the stability of several wave modes of collective oscillations of moving <span class="hlt">particles</span>. We find that, when a <span class="hlt">particle</span> moves without interacting with <span class="hlt">particles</span> that are positioned in a diagonally forward or backward direction, the stable region of the <span class="hlt">particle</span> flow is completely removed by the elliptically polarized mode.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/7565389','P