Science.gov

Sample records for real-time dynamic modeling

  1. A channel dynamics model for real-time flood forecasting

    USGS Publications Warehouse

    Hoos, A.B.; Koussis, A.D.; Beale, G.O.

    1989-01-01

    A new channel dynamics scheme ASPIRE (alternative system predictor in real time), designed specifically for real-time river flow forecasting, is introduced to reduce uncertainty in the forecast. ASPIRE is a storage routing model that limits the influence of catchment model forecast errors to the downstream station closest to the catchment. Comparisons with the Muskingum routing scheme in field tests suggest that the ASPIRE scheme can provide more accurate forecasts, probably because discharge observations are used to a maximum advantage and routing reaches (and model errors in each reach) are uncoupled. Using ASPIRE in conjunction with the Kalman filter did not improve forecast accuracy relative to a deterministic updating procedure. Theoretical analysis suggests that this is due to a large process noise to measurement noise ratio. -Authors

  2. A Stochastic-Dynamic Model for Real Time Flood Forecasting

    NASA Astrophysics Data System (ADS)

    Chow, K. C. A.; Watt, W. E.; Watts, D. G.

    1983-06-01

    A stochastic-dynamic model for real time flood forecasting was developed using Box-Jenkins modelling techniques. The purpose of the forecasting system is to forecast flood levels of the Saint John River at Fredericton, New Brunswick. The model consists of two submodels: an upstream model used to forecast the headpond level at the Mactaquac Dam and a downstream model to forecast the water level at Fredericton. Inputs to the system are recorded values of the water level at East Florenceville, the headpond level and gate position at Mactaquac, and the water level at Fredericton. The model was calibrated for the spring floods of 1973, 1974, 1977, and 1978, and its usefulness was verified for the 1979 flood. The forecasting results indicated that the stochastic-dynamic model produces reasonably accurate forecasts for lead times up to two days. These forecasts were then compared to those from the existing forecasting system and were found to be as reliable as those from the existing system.

  3. Improved Real-Time Helicopter Flight Dynamics Modelling

    NASA Astrophysics Data System (ADS)

    Haycock, Bruce Charles

    The University of Toronto Institute for Aerospace Studies has a number of previously developed real-time helicopter models for piloted simulations. An area of concern with physics-based helicopter models is that they often have an inaccurate off-axis response to cyclic control inputs compared to flight test data. To explain the cause of this problem, several theories have been put forth in the literature concerning which aspects are modelled incorrectly or not at all, including blade elasticity, rotor wake distortion and curvature, and unsteady aerodynamic effects. In this thesis these modelling improvements were implemented and their effectiveness evaluated. To include blade elasticity, a rotor model was developed using a Ritz expansion approach with constrained elastic modes. The effect of including these features on the on-axis and off-axis response of the UTIAS helicopter models was examined. The various improvements were successful in altering the off-axis response, with notable improvements in some areas, without disrupting the on-axis response. In some conditions, the magnitude of change due to flexibility was greater than differences noted due to dynamic wake distortion or unsteady aerodynamics. The best results were obtained when blade flexibility and wake distortion were used together, which is also the most physically accurate model. The impact of these changes was also evaluated from a pilot-in-the-loop perspective, quantifying the perceived changes using simulation fidelity ratings. Since this is a newly developed metric, the simulator was first evaluated using the original baseline vehicle models. Through this process, experience could be gained in the usage of the fidelity rating scale, while also examining what effect changes to the dynamics had on the overall simulator fidelity rating obtained. While an improved match to flight test data was found to lead to a higher rated fidelity, there was a limit to how high these improvements could increase

  4. Computer Modeling of Real-Time Dynamic Lighting

    NASA Technical Reports Server (NTRS)

    Maida, James C.; Pace, J.; Novak, J.; Russo, Dane M. (Technical Monitor)

    2000-01-01

    Space Station tasks involve procedures that are very complex and highly dependent on the availability of visual information. In many situations, cameras are used as tools to help overcome the visual and physical restrictions associated with space flight. However, these cameras are effected by the dynamic lighting conditions of space. Training for these is conditions is necessary. The current project builds on the findings of an earlier NRA funded project, which revealed improved performance by humans when trained with computer graphics and lighting effects such as shadows and glare.

  5. Real-Time Dynamic Modeling - Data Information Requirements and Flight Test Results

    NASA Technical Reports Server (NTRS)

    Morelli, Eugene A.; Smith, Mark S.

    2008-01-01

    Practical aspects of identifying dynamic models for aircraft in real time were studied. Topics include formulation of an equation-error method in the frequency domain to estimate non-dimensional stability and control derivatives in real time, data information content for accurate modeling results, and data information management techniques such as data forgetting, incorporating prior information, and optimized excitation. Real-time dynamic modeling was applied to simulation data and flight test data from a modified F-15B fighter aircraft, and to operational flight data from a subscale jet transport aircraft. Estimated parameter standard errors and comparisons with results from a batch output-error method in the time domain were used to demonstrate the accuracy of the identified real-time models.

  6. Real-Time Dynamic Modeling - Data Information Requirements and Flight Test Results

    NASA Technical Reports Server (NTRS)

    Morelli, Eugene A.; Smith, Mark S.

    2010-01-01

    Practical aspects of identifying dynamic models for aircraft in real time were studied. Topics include formulation of an equation-error method in the frequency domain to estimate non-dimensional stability and control derivatives in real time, data information content for accurate modeling results, and data information management techniques such as data forgetting, incorporating prior information, and optimized excitation. Real-time dynamic modeling was applied to simulation data and flight test data from a modified F-15B fighter aircraft, and to operational flight data from a subscale jet transport aircraft. Estimated parameter standard errors, prediction cases, and comparisons with results from a batch output-error method in the time domain were used to demonstrate the accuracy of the identified real-time models.

  7. Real-time forecasting of infectious disease dynamics with a stochastic semi-mechanistic model.

    PubMed

    Funk, Sebastian; Camacho, Anton; Kucharski, Adam J; Eggo, Rosalind M; Edmunds, W John

    2016-12-16

    Real-time forecasts of infectious diseases can help public health planning, especially during outbreaks. If forecasts are generated from mechanistic models, they can be further used to target resources or to compare the impact of possible interventions. However, paremeterising such models is often difficult in real time, when information on behavioural changes, interventions and routes of transmission are not readily available. Here, we present a semi-mechanistic model of infectious disease dynamics that was used in real time during the 2013-2016 West African Ebola epidemic, and show fits to a Ebola Forecasting Challenge conducted in late 2015 with simulated data mimicking the true epidemic. We assess the performance of the model in different situations and identify strengths and shortcomings of our approach. Models such as the one presented here which combine the power of mechanistic models with the flexibility to include uncertainty about the precise outbreak dynamics may be an important tool in combating future outbreaks.

  8. Langevin model for real-time Brownian dynamics of interacting nanodefects in irradiated metals

    SciTech Connect

    Dudarev, S. L.; Arakawa, K.; Mori, H.; Yao, Z.; Jenkins, M. L.; Derlet, P. M.

    2010-06-01

    In situ real-time electron microscope observations of metals irradiated with ultrahigh-energy electrons or energetic ions show that the dynamics of microstructural evolution in these materials is strongly influenced by long-range elastic interactions between mobile nanoscale radiation defects. Treating long-range interactions is also necessary for modeling microstructures formed in ex situ high-dose-rate ion-beam irradiation experiments, and for interpolating the ion-beam irradiation data to the low-dose-rate limit characterizing the neutron irradiation environments of fission or fusion power plants. We show that simulations, performed using an algorithm where nanoscale radiation defects are treated as interacting Langevin particles, are able to match and explain the real-time dynamics of nanodefects observed in in situ electron microscope experiments.

  9. Modeling of galfenol bending actuator considering nonlinear hysteresis and dynamic real-time control strategy

    NASA Astrophysics Data System (ADS)

    Shu, Liang; Wu, Guichu; Chen, Dingfang; Dapino, Marcelo J.

    2016-03-01

    On active bending structures, the actuation direction and the excitation field direction are not the same. Simple lumped parameter models are inadequate to describe the relationship between output displacement and input field. In this paper, a dynamic distributed parameter model is presented to describe the system dynamics of a galfenol bending actuator. To consider nonlinearities and hysteresis in bending, a nonlinear magnetomechanical model is developed to characterize the hysteretic magnetostriction generated by the galfenol layer. A dynamic real-time control strategy is proposed to compensate for hysteresis. A nonlinear inverse filter is constructed to linearize the hysteresis based on the proposed distributed parameter model. In order to increase the calculation efficiency, a new iteration method is proposed to calculate the filter. The iteration stepsize of the input field can be adaptively updated according to the inverting error. Simulation results show that significant enhancement of convergence efficiency can be achieved by using the proposed method compared with the existing fixed step size method. Experiments have been conducted to verify the real-time control strategy.

  10. Dynamic fuel cell stack model for real-time simulation based on system identification

    NASA Astrophysics Data System (ADS)

    Meiler, M.; Schmid, O.; Schudy, M.; Hofer, E. P.

    The authors have been developing an empirical mathematical model to predict the dynamic behaviour of a polymer electrolyte membrane fuel cell (PEMFC) stack. Today there is a great number of models, describing steady-state behaviour of fuel cells by estimating the equilibrium voltage for a certain set of operating parameters, but models capable of predicting the transient process between two steady-state points are rare. However, in automotive applications round about 80% of operating situations are dynamic. To improve the reliability of fuel cell systems by model-based control for real-time simulation dynamic fuel cell stack model is needed. Physical motivated models, described by differential equations, usually are complex and need a lot of computing time. To meet the real-time capability the focus is set on empirical models. Fuel cells are highly nonlinear systems, so often used auto-regressive (AR), output-error (OE) or Box-Jenkins (BJ) models do not accomplish satisfying accuracy. Best results are achieved by splitting the behaviour into a nonlinear static and a linear dynamic subsystem, a so-called Uryson-Model. For system identification and model validation load steps with different amplitudes are applied to the fuel cell stack at various operation points and the voltage response is recorded. The presented model is implemented in MATLAB environment and has a computing time of less than 1 ms per step on a standard desktop computer with a 2.8 MHz CPU and 504 MB RAM. Lab tests are carried out at DaimlerChrysler R&D Centre with DaimlerChrysler PEMFC hardware and a good agreement is found between model simulations and lab tests.

  11. Dynamics of symmetry breaking during quantum real-time evolution in a minimal model system.

    PubMed

    Heyl, Markus; Vojta, Matthias

    2014-10-31

    One necessary criterion for the thermalization of a nonequilibrium quantum many-particle system is ergodicity. It is, however, not sufficient in cases where the asymptotic long-time state lies in a symmetry-broken phase but the initial state of nonequilibrium time evolution is fully symmetric with respect to this symmetry. In equilibrium, one particular symmetry-broken state is chosen as a result of an infinitesimal symmetry-breaking perturbation. From a dynamical point of view the question is: Can such an infinitesimal perturbation be sufficient for the system to establish a nonvanishing order during quantum real-time evolution? We study this question analytically for a minimal model system that can be associated with symmetry breaking, the ferromagnetic Kondo model. We show that after a quantum quench from a completely symmetric state the system is able to break its symmetry dynamically and discuss how these features can be observed experimentally.

  12. Real-time computational attention model for dynamic scenes analysis: from implementation to evaluation

    NASA Astrophysics Data System (ADS)

    Courboulay, Vincent; Perreira Da Silva, Matthieu

    2012-06-01

    Providing real time analysis of the huge amount of data generated by computer vision algorithms in interactive applications is still an open problem. It promises great advances across a wide variety of fields. When using dynamics scene analysis algorithms for computer vision, a trade-off must be found between the quality of the results expected, and the amount of computer resources allocated for each task. It is usually a design time decision, implemented through the choice of pre-defined algorithms and parameters. However, this way of doing limits the generality of the system. Using an adaptive vision system provides a more flexible solution as its analysis strategy can be changed according to the new information available. As a consequence, such a system requires some kind of guiding mechanism to explore the scene faster and more efficiently. We propose a visual attention system that it adapts its processing according to the interest (or salience) of each element of the dynamic scene. Somewhere in between hierarchical salience based and competitive distributed, we propose a hierarchical yet competitive and non salience based model. Our original approach allows the generation of attentional focus points without the need of neither saliency map nor explicit inhibition of return mechanism. This new realtime computational model is based on a preys / predators system. The use of this kind of dynamical system is justified by an adjustable trade-off between nondeterministic attentional behavior and properties of stability, reproducibility and reactiveness.

  13. Transfer of Real-time Dynamic Radiation Environment Assimilation Model; Research to Operation

    NASA Astrophysics Data System (ADS)

    Cho, K. S. F.; Hwang, J.; Shin, D. K.; Kim, G. J.; Morley, S.; Henderson, M. G.; Friedel, R. H.; Reeves, G. D.

    2015-12-01

    Real-time Dynamic Radiation Environment Assimilation Model (rtDREAM) was developed by LANL for nowcast of energetic electrons' flux at the radiation belt to quantify potential risks from radiation damage at the satellites. Assimilated data are from multiple sources including LANL assets (GEO, GPS). For transfer from research to operation of the rtDREAM code, LANL/KSWC/NOAA makes a Memorandum Of Understanding (MOU) on the collaboration between three parts. By this MOU, KWSC/RRA provides all the support for transitioning the research version of DREAM to operations. KASI is primarily responsible for providing all the interfaces between the current scientific output formats of the code and useful space weather products that can be used and accessed through the web. In the second phase, KASI will be responsible in performing the work needed to transform the Van Allen Probes beacon data into "DREAM ready" inputs. KASI will also provide the "operational" code framework and additional data preparation, model output, display and web page codes back to LANL and SWPC. KASI is already a NASA partnering ground station for the Van Allen Probes' space weather beacon data and can here show use and utility of these data for comparison between rtDREAM and observations by web. NOAA has offered to take on some of the data processing tasks specific to the GOES data.

  14. Cell Models Adapted to Real-Time Imaging of the Cytoskeleton Dynamics in Altered Gravity

    NASA Astrophysics Data System (ADS)

    Willems, Jérôme; Deroanne, Christophe; Colige, Alain; Garbacki, Nancy

    2014-11-01

    Spatial and temporal regulation of cell phenotype by mechanical forces is a growing field of research in health sciences since these stimuli influence cellular functions, such as proliferation, migration, differentiation and gene expression. In the context of the Fluolive project selected by the European Space Agency and aiming at evaluating the impact of gravity alterations on the cell phenotype, we have developed new bone-derived cell lines adapted for live-cell imaging of the cytoskeleton. Osteoblastic cells derived from human osteosarcomas were used as experimental models. U2-OS and SaoS-2 cells stably expressing TagGFP2- β-actin and mCherry- α-tubulin were established and single-cell clonal cultures were characterized in terms of recombinant proteins production and localization, fluorescence intensity, cell proliferation and migration rates. Living fluorescently-tagged cell lines allow real-time fluorescence microscopy of the cytoskeleton dynamics without bleaching and without alteration of cell morphology. U2-OS and SaoS-2 TagGFP2- β-actin and mCherry- α-tubulin clones will be used to monitor the effect of mechanical forces in models of altered gravity on Earth and possibly on the ISS.

  15. Test Cases for Wind Power Plant Dynamic Models on Real-Time Digital Simulator: Preprint

    SciTech Connect

    Singh, M.; Muljadi, E.; Gevorgian, V.

    2012-06-01

    The objective of this paper is to present test cases for wind turbine generator and wind power plant models commonly used during commissioning of wind power plants to ensure grid integration compatibility. In this paper, different types of wind power plant models based on the Western Electricity Coordinating Council Wind Generator Modeling Group's standardization efforts are implemented on a real-time digital simulator, and different test cases are used to gauge their grid integration capability. The low-voltage ride through and reactive power support capability and limitations of wind turbine generators under different grid conditions are explored. Several types of transient events (e.g., symmetrical and unsymmetrical faults, frequency dips) are included in the test cases. The differences in responses from different types of wind turbine are discussed in detail.

  16. A simple dynamic engine model for use in a real-time aircraft simulation with thrust vectoring

    NASA Technical Reports Server (NTRS)

    Johnson, Steven A.

    1990-01-01

    A simple dynamic engine model was developed for use in thrust vectoring control law development and real-time aircraft simulation. Engine dynamics were simulated using a throttle rate limiter and low-pass filter. This paper includes a description of a method to account for axial thrust loss resulting from thrust vectoring and the development of the simple dynamic engine model and its incorporation into the F-18 high alpha research vehicle (HARV) thrust vectoring simulation. The simple dynamic engine model was evaluated at Mach 0.2, 35,000-ft altitude and at Mach 0.7, 35,000-ft altitude. The simple dynamic engine model is within 3 percent of the steady state response, and within 25 percent of the transient response of the complete nonlinear dynamic engine model.

  17. Modeling fast electron dynamics with real-time time-dependent density functional theory: application to small molecules and chromophores

    SciTech Connect

    Lopata, Kenneth A.; Govind, Niranjan

    2011-05-10

    The response of matter to external fields forms the basis for a vast wealth of fundamental physical processes ranging from light harvesting to nanoscale electron transport. Accurately modeling ultrafast electron dynamics in excited systems thus o_ers unparalleled insight, but requires an inherently non-linear time-resolved approach. To this end, an e_cient and massively parallel real-time real-space time-dependent density functional theory (RT-TDDFT) implementation in NWChem is presented. The implementation is first validated against linearresponse TDDFT and experimental results for a series of molecules subjected to small electric field perturbations. Second, non-linear excitation of green fluorescent protein is studied, which shows a blue-shift in the spectrum with increasing perturbation, as well as a saturation in absorption. Next, the charge dynamics of optically excited zinc porphyrin is presented in real-time and real-space, with relevance to charge injection in photovoltaic devices. Finally, intermolecular excitation in an adenine-thymine base pair is studied using the BNL range separated functional [Baer, R.; Neuhauser, D. Phys. Rev. Lett. 2005, 94, 043002], demonstrating the utility of a real-time approach in capturing charge transfer processes.

  18. A tool for modeling concurrent real-time computation

    NASA Technical Reports Server (NTRS)

    Sharma, D. D.; Huang, Shie-Rei; Bhatt, Rahul; Sridharan, N. S.

    1990-01-01

    Real-time computation is a significant area of research in general, and in AI in particular. The complexity of practical real-time problems demands use of knowledge-based problem solving techniques while satisfying real-time performance constraints. Since the demands of a complex real-time problem cannot be predicted (owing to the dynamic nature of the environment) powerful dynamic resource control techniques are needed to monitor and control the performance. A real-time computation model for a real-time tool, an implementation of the QP-Net simulator on a Symbolics machine, and an implementation on a Butterfly multiprocessor machine are briefly described.

  19. A simple dynamic engine model for use in a real-time aircraft simulation with thrust vectoring

    NASA Technical Reports Server (NTRS)

    Johnson, Steven A.

    1990-01-01

    A simple dynamic engine model was developed at the NASA Ames Research Center, Dryden Flight Research Facility, for use in thrust vectoring control law development and real-time aircraft simulation. The simple dynamic engine model of the F404-GE-400 engine (General Electric, Lynn, Massachusetts) operates within the aircraft simulator. It was developed using tabular data generated from a complete nonlinear dynamic engine model supplied by the manufacturer. Engine dynamics were simulated using a throttle rate limiter and low-pass filter. Included is a description of a method to account for axial thrust loss resulting from thrust vectoring. In addition, the development of the simple dynamic engine model and its incorporation into the F-18 high alpha research vehicle (HARV) thrust vectoring simulation. The simple dynamic engine model was evaluated at Mach 0.2, 35,000 ft altitude and at Mach 0.7, 35,000 ft altitude. The simple dynamic engine model is within 3 percent of the steady state response, and within 25 percent of the transient response of the complete nonlinear dynamic engine model.

  20. Real-time prediction of respiratory motion based on a local dynamic model in an augmented space

    NASA Astrophysics Data System (ADS)

    Hong, S.-M.; Jung, B.-H.; Ruan, D.

    2011-03-01

    Motion-adaptive radiotherapy aims to deliver ablative radiation dose to the tumor target with minimal normal tissue exposure, by accounting for real-time target movement. In practice, prediction is usually necessary to compensate for system latency induced by measurement, communication and control. This work focuses on predicting respiratory motion, which is most dominant for thoracic and abdominal tumors. We develop and investigate the use of a local dynamic model in an augmented space, motivated by the observation that respiratory movement exhibits a locally circular pattern in a plane augmented with a delayed axis. By including the angular velocity as part of the system state, the proposed dynamic model effectively captures the natural evolution of respiratory motion. The first-order extended Kalman filter is used to propagate and update the state estimate. The target location is predicted by evaluating the local dynamic model equations at the required prediction length. This method is complementary to existing work in that (1) the local circular motion model characterizes 'turning', overcoming the limitation of linear motion models; (2) it uses a natural state representation including the local angular velocity and updates the state estimate systematically, offering explicit physical interpretations; (3) it relies on a parametric model and is much less data-satiate than the typical adaptive semiparametric or nonparametric method. We tested the performance of the proposed method with ten RPM traces, using the normalized root mean squared difference between the predicted value and the retrospective observation as the error metric. Its performance was compared with predictors based on the linear model, the interacting multiple linear models and the kernel density estimator for various combinations of prediction lengths and observation rates. The local dynamic model based approach provides the best performance for short to medium prediction lengths under relatively

  1. Real-time dynamics and proposal for feasible experiments of lattice gauge-Higgs model simulated by cold atoms

    NASA Astrophysics Data System (ADS)

    Kuno, Yoshihito; Kasamatsu, Kenichi; Takahashi, Yoshiro; Ichinose, Ikuo; Matsui, Tetsuo

    2015-06-01

    Lattice gauge theory has provided a crucial non-perturbative method in studying canonical models in high-energy physics such as quantum chromodynamics. Among other models of lattice gauge theory, the lattice gauge-Higgs model is a quite important one because it describes a wide variety of phenomena/models related to the Anderson-Higgs mechanism, such as superconductivity, the standard model of particle physics, and the inflation process of the early Universe. In this paper, we first show that atomic description of the lattice gauge model allows us to explore real-time dynamics of the gauge variables by using the Gross-Pitaevskii equations. Numerical simulations of the time development of an electric flux reveal some interesting characteristics of the dynamic aspect of the model and determine its phase diagram. Next, to realize a quantum simulator of the U(1) lattice gauge-Higgs model on an optical lattice filled by cold atoms, we propose two feasible methods: (i) Wannier states in the excited bands and (ii) dipolar atoms in a multilayer optical lattice. We pay attention to the constraint of Gauss's law and avoid nonlocal gauge interactions.

  2. Compaction-Based Deformable Terrain Model as an Interface for Real-Time Vehicle Dynamics Simulations

    DTIC Science & Technology

    2013-04-16

    to vehicular loads, and the resulting visco-elastic-plastic stress/strain on the affected soil volume. Pedo transfer functions allow for the... resulting visco-elastic-plastic stress/strain on the affected soil volume. Pedo transfer functions allow for the calculation of the soil mechanics model...in section 2. Example simulations will include timing and profiling results for sequential, CPU parallel and CPU & GPU parallel implementations in

  3. Dynamic quality of service model for improving performance of multimedia real-time transmission in industrial networks.

    PubMed

    Gopalakrishnan, Ravichandran C; Karunakaran, Manivannan

    2014-01-01

    Nowadays, quality of service (QoS) is very popular in various research areas like distributed systems, multimedia real-time applications and networking. The requirements of these systems are to satisfy reliability, uptime, security constraints and throughput as well as application specific requirements. The real-time multimedia applications are commonly distributed over the network and meet various time constraints across networks without creating any intervention over control flows. In particular, video compressors make variable bit-rate streams that mismatch the constant-bit-rate channels typically provided by classical real-time protocols, severely reducing the efficiency of network utilization. Thus, it is necessary to enlarge the communication bandwidth to transfer the compressed multimedia streams using Flexible Time Triggered- Enhanced Switched Ethernet (FTT-ESE) protocol. FTT-ESE provides automation to calculate the compression level and change the bandwidth of the stream. This paper focuses on low-latency multimedia transmission over Ethernet with dynamic quality-of-service (QoS) management. This proposed framework deals with a dynamic QoS for multimedia transmission over Ethernet with FTT-ESE protocol. This paper also presents distinct QoS metrics based both on the image quality and network features. Some experiments with recorded and live video streams show the advantages of the proposed framework. To validate the solution we have designed and implemented a simulator based on the Matlab/Simulink, which is a tool to evaluate different network architecture using Simulink blocks.

  4. Dynamic Quality of Service Model for Improving Performance of Multimedia Real-Time Transmission in Industrial Networks

    PubMed Central

    Gopalakrishnan, Ravichandran C.; Karunakaran, Manivannan

    2014-01-01

    Nowadays, quality of service (QoS) is very popular in various research areas like distributed systems, multimedia real-time applications and networking. The requirements of these systems are to satisfy reliability, uptime, security constraints and throughput as well as application specific requirements. The real-time multimedia applications are commonly distributed over the network and meet various time constraints across networks without creating any intervention over control flows. In particular, video compressors make variable bit-rate streams that mismatch the constant-bit-rate channels typically provided by classical real-time protocols, severely reducing the efficiency of network utilization. Thus, it is necessary to enlarge the communication bandwidth to transfer the compressed multimedia streams using Flexible Time Triggered- Enhanced Switched Ethernet (FTT-ESE) protocol. FTT-ESE provides automation to calculate the compression level and change the bandwidth of the stream. This paper focuses on low-latency multimedia transmission over Ethernet with dynamic quality-of-service (QoS) management. This proposed framework deals with a dynamic QoS for multimedia transmission over Ethernet with FTT-ESE protocol. This paper also presents distinct QoS metrics based both on the image quality and network features. Some experiments with recorded and live video streams show the advantages of the proposed framework. To validate the solution we have designed and implemented a simulator based on the Matlab/Simulink, which is a tool to evaluate different network architecture using Simulink blocks. PMID:25170768

  5. An Optimization Framework for Dynamic, Distributed Real-Time Systems

    NASA Technical Reports Server (NTRS)

    Eckert, Klaus; Juedes, David; Welch, Lonnie; Chelberg, David; Bruggerman, Carl; Drews, Frank; Fleeman, David; Parrott, David; Pfarr, Barbara

    2003-01-01

    Abstract. This paper presents a model that is useful for developing resource allocation algorithms for distributed real-time systems .that operate in dynamic environments. Interesting aspects of the model include dynamic environments, utility and service levels, which provide a means for graceful degradation in resource-constrained situations and support optimization of the allocation of resources. The paper also provides an allocation algorithm that illustrates how to use the model for producing feasible, optimal resource allocations.

  6. Real-time DIRCM system modeling

    NASA Astrophysics Data System (ADS)

    Petersson, Mikael

    2004-12-01

    Directed infrared countermeasures (DIRCM) play an increasingly important role in electronic warfare to counteract threats posed by infrared seekers. The usefulness and performance of such countermeasures depend, for example, on atmospheric conditions (attenuation and turbulence) and platform vibrations, causing pointing and tracking errors for the laser beam and reducing the power transferred to the seeker aperture. These problems make it interesting to simulate the performance of a DIRCM system in order to understand how easy or difficult it is to counteract an approaching threat and evaluate limiting factors in various situations. This paper describes a DIRCM model that has been developed, including atmospheric effects such as attenuation and turbulence as well as closed loop tracking algorithms, where the retro reflex of the laser is used for the pointing control of the beam. The DIRCM model is part of a large simulation framework (EWSim), which also incorporates several descriptions of different seekers (e.g. reticle, rosette, centroid, nutating cross) and models of robot dynamics. Effects of a jamming laser on a specific threat can be readily verified by simulations within this framework. The duel between missile and countermeasure is simulated in near real-time and visualized graphically in 3D. A typical simulation with a reticle seeker jammed by a modulated laser is included in the paper.

  7. A wavelet-based non-linear autoregressive with exogenous inputs (WNARX) dynamic neural network model for real-time flood forecasting using satellite-based rainfall products

    NASA Astrophysics Data System (ADS)

    Nanda, Trushnamayee; Sahoo, Bhabagrahi; Beria, Harsh; Chatterjee, Chandranath

    2016-08-01

    Although flood forecasting and warning system is a very important non-structural measure in flood-prone river basins, poor raingauge network as well as unavailability of rainfall data in real-time could hinder its accuracy at different lead times. Conversely, since the real-time satellite-based rainfall products are now becoming available for the data-scarce regions, their integration with the data-driven models could be effectively used for real-time flood forecasting. To address these issues in operational streamflow forecasting, a new data-driven model, namely, the wavelet-based non-linear autoregressive with exogenous inputs (WNARX) is proposed and evaluated in comparison with four other data-driven models, viz., the linear autoregressive moving average with exogenous inputs (ARMAX), static artificial neural network (ANN), wavelet-based ANN (WANN), and dynamic nonlinear autoregressive with exogenous inputs (NARX) models. First, the quality of input rainfall products of Tropical Rainfall Measuring Mission Multi-satellite Precipitation Analysis (TMPA), viz., TRMM and TRMM-real-time (RT) rainfall products is assessed through statistical evaluation. The results reveal that the satellite rainfall products moderately correlate with the observed rainfall, with the gauge-adjusted TRMM product outperforming the real-time TRMM-RT product. The TRMM rainfall product better captures the ground observations up to 95 percentile range (30.11 mm/day), although the hit rate decreases for high rainfall intensity. The effect of antecedent rainfall (AR) and climate forecast system reanalysis (CFSR) temperature product on the catchment response is tested in all the developed models. The results reveal that, during real-time flow simulation, the satellite-based rainfall products generally perform worse than the gauge-based rainfall. Moreover, as compared to the existing models, the flow forecasting by the WNARX model is way better than the other four models studied herein with the

  8. Real-time remote scientific model validation

    NASA Technical Reports Server (NTRS)

    Frainier, Richard; Groleau, Nicolas

    1994-01-01

    This paper describes flight results from the use of a CLIPS-based validation facility to compare analyzed data from a space life sciences (SLS) experiment to an investigator's preflight model. The comparison, performed in real-time, either confirms or refutes the model and its predictions. This result then becomes the basis for continuing or modifying the investigator's experiment protocol. Typically, neither the astronaut crew in Spacelab nor the ground-based investigator team are able to react to their experiment data in real time. This facility, part of a larger science advisor system called Principal Investigator in a Box, was flown on the space shuttle in October, 1993. The software system aided the conduct of a human vestibular physiology experiment and was able to outperform humans in the tasks of data integrity assurance, data analysis, and scientific model validation. Of twelve preflight hypotheses associated with investigator's model, seven were confirmed and five were rejected or compromised.

  9. Neural Network Retinal Model Real Time Implementation

    DTIC Science & Technology

    1992-09-02

    addresses the specific needs of vision processing. The goal of this SBIR Phase I project has been to take a significant neural network vision...application and to map it onto dedicated hardware for real time implementation. The neural network was already demonstrated using software simulation on a...general purpose computer. During Phase 1, HNC took a neural network model of the retina and, using HNC’s Vision Processor (ViP) prototype hardware

  10. Real-Time Ocean Modeling Systems

    DTIC Science & Technology

    2013-10-22

    2002 2. REPORT TYPE 3. DATES COVERED (From - To) Journal Article 4 . TITLE AND SUBTITLE Real-time 16iebaf Modeling Systems \\&&»A 5a...Director NCST E.O. Hartwig, 7000 Public Affairs (Unclassified/ Unlimited Only), Code 7n30 4 Division, Code Author, Code HQ-NRL 5511/6 (Rev. 12-93...according to the routing in Section 4 . 1. NRL Reports Submit the diskette (if available), manuscript, typed double-spaced, complete with tables

  11. Real-time dynamic simulation of the Cassini spacecraft using DARTS. Part 2: Parallel/vectorized real-time implementation

    NASA Technical Reports Server (NTRS)

    Fijany, A.; Roberts, J. A.; Jain, A.; Man, G. K.

    1993-01-01

    Part 1 of this paper presented the requirements for the real-time simulation of Cassini spacecraft along with some discussion of the DARTS algorithm. Here, in Part 2 we discuss the development and implementation of parallel/vectorized DARTS algorithm and architecture for real-time simulation. Development of the fast algorithms and architecture for real-time hardware-in-the-loop simulation of spacecraft dynamics is motivated by the fact that it represents a hard real-time problem, in the sense that the correctness of the simulation depends on both the numerical accuracy and the exact timing of the computation. For a given model fidelity, the computation should be computed within a predefined time period. Further reduction in computation time allows increasing the fidelity of the model (i.e., inclusion of more flexible modes) and the integration routine.

  12. Dynamic shape modeling of the mitral valve from real-time 3D ultrasound images using continuous medial representation

    NASA Astrophysics Data System (ADS)

    Pouch, Alison M.; Yushkevich, Paul A.; Jackson, Benjamin M.; Gorman, Joseph H., III; Gorman, Robert C.; Sehgal, Chandra M.

    2012-03-01

    Purpose: Patient-specific shape analysis of the mitral valve from real-time 3D ultrasound (rt-3DUS) has broad application to the assessment and surgical treatment of mitral valve disease. Our goal is to demonstrate that continuous medial representation (cm-rep) is an accurate valve shape representation that can be used for statistical shape modeling over the cardiac cycle from rt-3DUS images. Methods: Transesophageal rt-3DUS data acquired from 15 subjects with a range of mitral valve pathology were analyzed. User-initialized segmentation with level sets and symmetric diffeomorphic normalization delineated the mitral leaflets at each time point in the rt-3DUS data series. A deformable cm-rep was fitted to each segmented image of the mitral leaflets in the time series, producing a 4D parametric representation of valve shape in a single cardiac cycle. Model fitting accuracy was evaluated by the Dice overlap, and shape interpolation and principal component analysis (PCA) of 4D valve shape were performed. Results: Of the 289 3D images analyzed, the average Dice overlap between each fitted cm-rep and its target segmentation was 0.880+/-0.018 (max=0.912, min=0.819). The results of PCA represented variability in valve morphology and localized leaflet thickness across subjects. Conclusion: Deformable medial modeling accurately captures valve geometry in rt-3DUS images over the entire cardiac cycle and enables statistical shape analysis of the mitral valve.

  13. Integrating real-time and manual monitored data to predict hillslope soil moisture dynamics with high spatio-temporal resolution using linear and non-linear models

    NASA Astrophysics Data System (ADS)

    Zhu, Qing; Zhou, Zhiwen; Duncan, Emily W.; Lv, Ligang; Liao, Kaihua; Feng, Huihui

    2017-02-01

    Spatio-temporal variability of soil moisture (θ) is a challenge that remains to be better understood. A trade-off exists between spatial coverage and temporal resolution when using the manual and real-time θ monitoring methods. This restricted the comprehensive and intensive examination of θ dynamics. In this study, we integrated the manual and real-time monitored data to depict the hillslope θ dynamics with good spatial coverage and temporal resolution. Linear (stepwise multiple linear regression-SMLR) and non-linear (support vector machines-SVM) models were used to predict θ at 39 manual sites (collected 1-2 times per month) with θ collected at three real-time monitoring sites (collected every 5 mins). By comparing the accuracies of SMLR and SVM for each depth and manual site, an optimal prediction model was then determined at this depth of this site. Results showed that θ at the 39 manual sites can be reliably predicted (root mean square errors <0.028 m3 m-3) using both SMLR and SVM. The linear or non-linear relationship between θ at each manual site and at the three real-time monitoring sites was the main reason for choosing SMLR or SVM as the optimal prediction model. The subsurface flow dynamics was an important factor that determined whether the relationship was linear or non-linear. Depth to bedrock, elevation, topographic wetness index, profile curvature, and θ temporal stability influenced the selection of prediction model since they were related to the subsurface soil water distribution and movement. Using this approach, hillslope θ spatial distributions at un-sampled times and dates can be predicted. Missing information of hillslope θ dynamics can be acquired successfully.

  14. A novel platelet-rich arterial thrombosis model in rabbits. Simple, reproducible, and dynamic real-time measurement by using double-opposing inverted-sutures model.

    PubMed

    Shieh, S J; Chiu, H Y; Shi, G Y; Wu, C M; Wang, J C; Chen, C H; Wu, H L

    2001-09-01

    Though numerous animal thrombosis models have been introduced, an easy, reliable, and reproducible arterial thrombosis model remains a continuing challenge prior to a thrombolytic study. In an effort to evaluate the efficiency of various recombinant thrombolytic agents with specific affinity to activated platelets in vivo, we developed a novel double-opposing inverted-sutures model to create a platelet-rich thrombus in the femoral artery of rabbits. The arteriotomy was done semicircumferentially, and variously sized microsurgical sutures were introduced intraluminally in a double-opposing inverted manner. The animals were divided into three groups according to the double-opposing inverted-sutures used: Group 1 with 10-0 nylon (n=6), Group 2 with 9-0 nylon (n=6), and Group 3 with 8-0 nylon (n=22). The superficial epigastric branch was cannulated with a thin polyethylene (PE) tube for intraarterial administration of the studied thrombolytic agent. The blood flow was continuously measured with a real-time ultrasonic flow meter. Within 2 h of installation of the sutures, there was no thrombus formation in either Group 1 or 2. In Group 3, the thrombosis rate was 91% (20 of 22) under a steady baseline flow (with an average of 12.23+/-2.40 ml/min). It was highly statistically significant with a P-value of .0000743 using Fisher's Exact Test. The averaged time to thrombosis was 21.8+/-9.8 min. The ultrasonic flow meter to record the dynamic real-time measurement of blood flow was a guideline for thrombus formation or dissolution, which was correlated with the morphological findings of stenotic status of the vessel detected by the Doppler sonography. The components of the thrombus were proven to be platelet-rich predominant by histological examination via hematoxylin and eosin (H&E) stain and transmission electron microscopy (TEM). To confirm that the double-opposing inverted-sutures model would be useful for a study of thrombolytic agents, we evaluated the effects of

  15. beta2-adrenergic receptor signaling and desensitization elucidated by quantitative modeling of real time cAMP dynamics.

    PubMed

    Violin, Jonathan D; DiPilato, Lisa M; Yildirim, Necmettin; Elston, Timothy C; Zhang, Jin; Lefkowitz, Robert J

    2008-02-01

    G protein-coupled receptor signaling is dynamically regulated by multiple feedback mechanisms, which rapidly attenuate signals elicited by ligand stimulation, causing desensitization. The individual contributions of these mechanisms, however, are poorly understood. Here, we use an improved fluorescent biosensor for cAMP to measure second messenger dynamics stimulated by endogenous beta(2)-adrenergic receptor (beta(2)AR) in living cells. beta(2)AR stimulation with isoproterenol results in a transient pulse of cAMP, reaching a maximal concentration of approximately 10 microm and persisting for less than 5 min. We investigated the contributions of cAMP-dependent kinase, G protein-coupled receptor kinases, and beta-arrestin to the regulation of beta(2)AR signal kinetics by using small molecule inhibitors, small interfering RNAs, and mouse embryonic fibroblasts. We found that the cAMP response is restricted in duration by two distinct mechanisms in HEK-293 cells: G protein-coupled receptor kinase (GRK6)-mediated receptor phosphorylation leading to beta-arrestin mediated receptor inactivation and cAMP-dependent kinase-mediated induction of cAMP metabolism by phosphodiesterases. A mathematical model of beta(2)AR signal kinetics, fit to these data, revealed that direct receptor inactivation by cAMP-dependent kinase is insignificant but that GRK6/beta-arrestin-mediated inactivation is rapid and profound, occurring with a half-time of 70 s. This quantitative system analysis represents an important advance toward quantifying mechanisms contributing to the physiological regulation of receptor signaling.

  16. Real-time estimation of dynamic functional connectivity networks.

    PubMed

    Monti, Ricardo Pio; Lorenz, Romy; Braga, Rodrigo M; Anagnostopoulos, Christoforos; Leech, Robert; Montana, Giovanni

    2017-01-01

    Two novel and exciting avenues of neuroscientific research involve the study of task-driven dynamic reconfigurations of functional connectivity networks and the study of functional connectivity in real-time. While the former is a well-established field within neuroscience and has received considerable attention in recent years, the latter remains in its infancy. To date, the vast majority of real-time fMRI studies have focused on a single brain region at a time. This is due in part to the many challenges faced when estimating dynamic functional connectivity networks in real-time. In this work, we propose a novel methodology with which to accurately track changes in time-varying functional connectivity networks in real-time. The proposed method is shown to perform competitively when compared to state-of-the-art offline algorithms using both synthetic as well as real-time fMRI data. The proposed method is applied to motor task data from the Human Connectome Project as well as to data obtained from a visuospatial attention task. We demonstrate that the algorithm is able to accurately estimate task-related changes in network structure in real-time. Hum Brain Mapp 38:202-220, 2017. © 2016 Wiley Periodicals, Inc.

  17. A new computational structure for real-time dynamics

    SciTech Connect

    Izaguirre, A. ); Hashimoto, Minoru )

    1992-08-01

    The authors present an efficient structure for the computation of robot dynamics in real time. The fundamental characteristic of this structure is the division of the computation into a high-priority synchronous task and low-priority background tasks, possibly sharing the resources of a conventional computing unit based on commercial microprocessors. The background tasks compute the inertial and gravitational coefficients as well as the forces due to the velocities of the joints. In each control sample period, the high-priority synchronous task computes the product of the inertial coefficients by the accelerations of the joints and performs the summation of the torques due to the velocities and gravitational forces. Kircanski et al. (1986) have shown that the bandwidth of the variation of joint angles and of their velocities is an order of magnitude less than the variation of joint accelerations. This result agrees with the experiments the authors have carried out using a PUMA 260 robot. Two main strategies contribute to reduce the computational burden associated with the evaluation of the dynamic equations. The first involves the use of efficient algorithms for the evaluation of the equations. The second is aimed at reducing the number of dynamic parameters by identifying beforehand the linear dependencies among these parameters, as well as carrying out a significance analysis of the parameters' contribution to the final joint torques. The actual code used to evaluate this dynamic model is entirely computer generated from experimental data, requiring no other manual intervention than performing a campaign of measurements.

  18. Coordinated scheduling for dynamic real-time systems

    NASA Technical Reports Server (NTRS)

    Natarajan, Swaminathan; Zhao, Wei

    1994-01-01

    In this project, we addressed issues in coordinated scheduling for dynamic real-time systems. In particular, we concentrated on design and implementation of a new distributed real-time system called R-Shell. The design objective of R-Shell is to provide computing support for space programs that have large, complex, fault-tolerant distributed real-time applications. In R-shell, the approach is based on the concept of scheduling agents, which reside in the application run-time environment, and are customized to provide just those resource management functions which are needed by the specific application. With this approach, we avoid the need for a sophisticated OS which provides a variety of generalized functionality, while still not burdening application programmers with heavy responsibility for resource management. In this report, we discuss the R-Shell approach, summarize the achievement of the project, and describe a preliminary prototype of R-Shell system.

  19. Integrating real-time and manual monitored data to predict hillslope soil moisture dynamics with high spatio-temporal resolution using linear and non-linear models

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spatio-temporal variability of soil moisture (') is a challenge that remains to be better understood. A trade-off exists between spatial coverage and temporal resolution when using the manual and real-time ' monitoring methods. This restricted the comprehensive and intensive examination of ' dynamic...

  20. Real-time high dynamic range laser scanning microscopy

    PubMed Central

    Vinegoni, C.; Leon Swisher, C.; Fumene Feruglio, P.; Giedt, R. J.; Rousso, D. L.; Stapleton, S.; Weissleder, R.

    2016-01-01

    In conventional confocal/multiphoton fluorescence microscopy, images are typically acquired under ideal settings and after extensive optimization of parameters for a given structure or feature, often resulting in information loss from other image attributes. To overcome the problem of selective data display, we developed a new method that extends the imaging dynamic range in optical microscopy and improves the signal-to-noise ratio. Here we demonstrate how real-time and sequential high dynamic range microscopy facilitates automated three-dimensional neural segmentation. We address reconstruction and segmentation performance on samples with different size, anatomy and complexity. Finally, in vivo real-time high dynamic range imaging is also demonstrated, making the technique particularly relevant for longitudinal imaging in the presence of physiological motion and/or for quantification of in vivo fast tracer kinetics during functional imaging. PMID:27032979

  1. Real-time high dynamic range laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Vinegoni, C.; Leon Swisher, C.; Fumene Feruglio, P.; Giedt, R. J.; Rousso, D. L.; Stapleton, S.; Weissleder, R.

    2016-04-01

    In conventional confocal/multiphoton fluorescence microscopy, images are typically acquired under ideal settings and after extensive optimization of parameters for a given structure or feature, often resulting in information loss from other image attributes. To overcome the problem of selective data display, we developed a new method that extends the imaging dynamic range in optical microscopy and improves the signal-to-noise ratio. Here we demonstrate how real-time and sequential high dynamic range microscopy facilitates automated three-dimensional neural segmentation. We address reconstruction and segmentation performance on samples with different size, anatomy and complexity. Finally, in vivo real-time high dynamic range imaging is also demonstrated, making the technique particularly relevant for longitudinal imaging in the presence of physiological motion and/or for quantification of in vivo fast tracer kinetics during functional imaging.

  2. Toward Dynamic Real-Time Informative Warning Systems

    NASA Astrophysics Data System (ADS)

    Pahle, Robert; Ozel, Filiz

    A great deal of research has been done to improve safety in the built environment. Disaster preparedness plans have been developed for a variety of situations; however, these plans often fail to convey sufficient information flow to the target audience. The literature discusses a variety of arguments that both support and limit giving information to the target audience. One of the arguments for limiting information is the assumption that people could panic and increase the difficulties at hand. Yet, a literature search for this paper indicates that target audience panics only in very rare situations. Furthermore, it shows that most people seek information about the event and that they actually try to make good decisions to ensure their survival. A system that could bring information to persons during an emergency could therefore address a variety of decision-making challenges in these tense situations. The handling of information could encompass a variety of scales: from national to urban to building scale. This paper looks into the realm of dynamic, real-time informative warning systems that deliver information to occupants of buildings during emergencies. It builds on a cognitive model for navigation in the built environment. A theoretical approach for the design of the warning message is discussed. Since this is an ongoing research project, only the results of the initial assessment will be presented here.

  3. Monte Carlo Study of Real Time Dynamics on the Lattice

    NASA Astrophysics Data System (ADS)

    Alexandru, Andrei; Başar, Gökçe; Bedaque, Paulo F.; Vartak, Sohan; Warrington, Neill C.

    2016-08-01

    Monte Carlo studies involving real time dynamics are severely restricted by the sign problem that emerges from a highly oscillatory phase of the path integral. In this Letter, we present a new method to compute real time quantities on the lattice using the Schwinger-Keldysh formalism via Monte Carlo simulations. The key idea is to deform the path integration domain to a complex manifold where the phase oscillations are mild and the sign problem is manageable. We use the previously introduced "contraction algorithm" to create a Markov chain on this alternative manifold. We substantiate our approach by analyzing the quantum mechanical anharmonic oscillator. Our results are in agreement with the exact ones obtained by diagonalization of the Hamiltonian. The method we introduce is generic and, in principle, applicable to quantum field theory albeit very slow. We discuss some possible improvements that should speed up the algorithm.

  4. Adaptive Modeling and Real-Time Simulation

    DTIC Science & Technology

    1984-01-01

    34 Artificial Inteligence , Vol. 13, pp. 27-39 (1980). Describes circumscription which is just the assumption that everything that is known to have a particular... Artificial Intelligence Truth Maintenance Planning Resolution Modeling Wcrld Models ~ .. ~2.. ASSTR AT (Coninue n evrse sieIf necesaran Identfy by...represents a marriage of (1) the procedural-network st, planning technology developed in artificial intelligence with (2) the PERT/CPM technology developed in

  5. Real-time extended dynamic range imaging in shearography

    SciTech Connect

    Groves, Roger M.; Pedrini, Giancarlo; Osten, Wolfgang

    2008-10-20

    Extended dynamic range (EDR) imaging is a postprocessing technique commonly associated with photography. Multiple images of a scene are recorded by the camera using different shutter settings and are merged into a single higher dynamic range image. Speckle interferometry and holography techniques require a well-modulated intensity signal to extract the phase information, and of these techniques shearography is most sensitive to different object surface reflectivities as it uses self-referencing from a sheared image. In this paper the authors demonstrate real-time EDR imaging in shearography and present experimental results from a difficult surface reflectivity sample: a wooden panel painting containing gold and dark earth color paint.

  6. Real-time inverse kinematics and inverse dynamics for lower limb applications using OpenSim.

    PubMed

    Pizzolato, C; Reggiani, M; Modenese, L; Lloyd, D G

    2017-03-01

    Real-time estimation of joint angles and moments can be used for rapid evaluation in clinical, sport, and rehabilitation contexts. However, real-time calculation of kinematics and kinetics is currently based on approximate solutions or generic anatomical models. We present a real-time system based on OpenSim solving inverse kinematics and dynamics without simplifications at 2000 frame per seconds with less than 31.5 ms of delay. We describe the software architecture, sensitivity analyses to minimise delays and errors, and compare offline and real-time results. This system has the potential to strongly impact current rehabilitation practices enabling the use of personalised musculoskeletal models in real-time.

  7. Method for Real-Time Model Based Structural Anomaly Detection

    NASA Technical Reports Server (NTRS)

    Smith, Timothy A. (Inventor); Urnes, James M., Sr. (Inventor); Reichenbach, Eric Y. (Inventor)

    2015-01-01

    A system and methods for real-time model based vehicle structural anomaly detection are disclosed. A real-time measurement corresponding to a location on a vehicle structure during an operation of the vehicle is received, and the real-time measurement is compared to expected operation data for the location to provide a modeling error signal. A statistical significance of the modeling error signal to provide an error significance is calculated, and a persistence of the error significance is determined. A structural anomaly is indicated, if the persistence exceeds a persistence threshold value.

  8. Architecture for dynamically reconfigurable real-time lossless compression

    NASA Astrophysics Data System (ADS)

    Carter, Alison J.; Audsley, Neil C.

    2004-05-01

    Image compression is a computationally intensive task, which can be undertaken most efficiently by dedicated hardware. If a portable device is to carry out real-time compression on a variety of image types, then it may be useful to reconfigure the circuitry dynamically. Using commercial off-the shelf (COTS) chips, reconfiguration is usually implemented by a complete re-load from memory, but it is also possible to perform a partial reconfiguration. This work studies the use of programmable hardware devices to implement the lossless JPEG compression algorithm in real-time on a stream of independent image frames. The data rate is faster than can be compressed serially in hardware by a single processor, so the operation is split amongst several processors. These are implemented as programmable circuits, together with necessary buffering of input and output data. The timing of input and output, bearing in mind the different, and context-dependent amounts of data due to Huffman coding, is analyzed using storage-timing graphs. Because there may be differing parameters from one frame to the next, several different configurations are prepared and stored, ready to load as required. The scheduling of these reconfigurations, and the distribution/recombination of data streams is studied, giving an analysis of the real-time performance.

  9. Capturing Real-Time Power System Dynamics: Opportunities and Challenges

    SciTech Connect

    Huang, Zhenyu; Zhou, Ning; Diao, Ruisheng; Wang, Shaobu; Elbert, Stephen T.; Meng, Da; Lu, Shuai

    2015-09-01

    The power grid evolves towards a new mix of generation and consumption that introduces new dynamic and stochastic behaviors. These emerging grid behaviors would invalidate the steady-state assumption in today’s state estimation – an essential function for real-time power grid operation. This paper examines this steady-state assumption and identifies the need for estimating dynamic states. Supporting technologies are presented as well as a proposed formulation for estimating dynamic states. Metrics for evaluating methods for solving the dynamic state estimation problem are proposed, with example results to illustrate the use of these metrics. The overall objective of this paper is to provide a basis that more research on this topic can follow.

  10. Real-Time Bioluminescent Tracking of Cellular Population Dynamics

    SciTech Connect

    Close, Dan; Sayler, Gary Steven; Xu, Tingting; Ripp, Steven Anthony

    2014-01-01

    Cellular population dynamics are routinely monitored across many diverse fields for a variety of purposes. In general, these dynamics are assayed either through the direct counting of cellular aliquots followed by extrapolation to the total population size, or through the monitoring of signal intensity from any number of externally stimulated reporter proteins. While both viable methods, here we describe a novel technique that allows for the automated, non-destructive tracking of cellular population dynamics in real-time. This method, which relies on the detection of a continuous bioluminescent signal produced through expression of the bacterial luciferase gene cassette, provides a low cost, low time-intensive means for generating additional data compared to alternative methods.

  11. Real-Time Bioluminescent Tracking of Cellular Population Dynamics

    PubMed Central

    Close, Dan; Xu, Tingling; Ripp, Steven; Sayler, Gary

    2015-01-01

    Cellular population dynamics are routinely monitored across many diverse fields for a variety of purposes. In general, these dynamics are assayed either through the direct counting of cellular aliquots followed by extrapolation to the total population size, or through the monitoring of signal intensity from any number of externally stimulated reporter proteins. While both viable methods, here we describe a novel technique that allows for the automated, non-destructive tracking of cellular population dynamics in real-time. This method, which relies on the detection of a continuous bioluminescent signal produced through expression of the bacterial luciferase gene cassette, provides a low cost, low time-intensive means for generating additional data compared to alternative methods. PMID:24166372

  12. Application of a dynamic in vitro model with real-time determination of acetylcholinesterase activity for the investigation of tabun analogues and oximes.

    PubMed

    Worek, Franz; Herkert, Nadja M; Koller, Marianne; Thiermann, Horst; Wille, Timo

    2015-12-25

    Tabun-inhibited acetylcholinesterase (AChE) is rather resistant towards reactivation by oximes in vitro while in vivo experiments showed some protection of animals poisoned by this chemical warfare nerve agent after treatment with an oxime and atropine. In addition, AChE inhibited by close tabun analogues, N,N-diethyltabun and N,N-di-n-propyltabun was completely resistant towards reactivation by oximes. In order to get more insight into potential mechanisms of this oxime resistance experiments with these toxic agents and the oximes obidoxime, 2-PAM, MMB-4 and HI-6 were performed utilizing a dynamic model with real-time determination of AChE activity. This experimental setup allowed the investigation of reactivation with minimized side reactions. The determined reactivation constants with tabun-inhibited human AChE were in good agreement with previously reported constants determined with a static model. N,N-diethyl- and N,N-di-n-propyltabun-inhibited human AChE could not be reactivated by oximes which indicates that the inadequate oxime effect was not due to re-inhibition by phosphonyloximes. Additional experiments with tabun-inhibited human and Rhesus monkey AChE revealed that no reactivation occurred with HI-6. These data give further support to the assumption that an interaction of tabun with residues in the active site gorge of AChE prevents effective reactivation by oximes, a mechanism which may also be the reason for the total oxime resistance of N,N-diethyl- and N,N-di-n-propyltabun-inhibited human AChE.

  13. Real-time dynamics of the confining string

    NASA Astrophysics Data System (ADS)

    Loshaj, Frasher

    Quantum chromodynamics (QCD) describes the interaction of quarks and gluons, which are charged under the color group. Due to confinement of color charge, only colorless hadrons are observed in experiment. At very short distances (hard processes), perturbation theory is a valid tool for calculations and predictions can be made which agree well with experiment. Confinement, which is not yet understood from first principles, is important even for hard processes, because after the perturbative evolution is finished, the final colored particles combine to create the final state hadrons. There are many effective theories of confinement developed over the years. We will consider the Abelian projection; the gauge theory becomes Abelian-like and the theory contains magnetic monopoles. Confinement happens due to the dual Meissner effect, where dual in this case means the roles of the electric and magnetic fields are reversed. The field between charges resembles that of an Abrikosov-Nielsen-Olesen vortex or string. Based on the Abelian nature of the confining string, because fermion zero modes are localized along the vortex and by considering very energetic jets, we assume that the dynamics along this string is described by massless quantum electrodynamics in 1+1 dimensions. This theory shares with QCD many important properties: confinement, chiral symmetry breaking, theta-vacuum, and is exactly soluble. We use the model to compute the fragmentation functions of jets in electron-positron annihilation and after fixing two adjustable parameters, we study the modification of fragmentation functions of jets in the QCD medium. We address an important puzzle in hadron scattering: the soft photon yield in processes with hadrons in the final state is much larger than what is expected from the Low theorem. We find that soft photons produced from currents induced during the real-time dynamics of jet fragmentation can contribute in the enhancement of photons. We compare the result with

  14. Real-Time Statistical Modeling of Blood Sugar.

    PubMed

    Otoom, Mwaffaq; Alshraideh, Hussam; Almasaeid, Hisham M; López-de-Ipiña, Diego; Bravo, José

    2015-10-01

    Diabetes is considered a chronic disease that incurs various types of cost to the world. One major challenge in the control of Diabetes is the real time determination of the proper insulin dose. In this paper, we develop a prototype for real time blood sugar control, integrated with the cloud. Our system controls blood sugar by observing the blood sugar level and accordingly determining the appropriate insulin dose based on patient's historical data, all in real time and automatically. To determine the appropriate insulin dose, we propose two statistical models for modeling blood sugar profiles, namely ARIMA and Markov-based model. Our experiment used to evaluate the performance of the two models shows that the ARIMA model outperforms the Markov-based model in terms of prediction accuracy.

  15. Spatio-temporal modeling for real-time ozone forecasting.

    PubMed

    Paci, Lucia; Gelfand, Alan E; Holland, David M

    2013-05-01

    The accurate assessment of exposure to ambient ozone concentrations is important for informing the public and pollution monitoring agencies about ozone levels that may lead to adverse health effects. High-resolution air quality information can offer significant health benefits by leading to improved environmental decisions. A practical challenge facing the U.S. Environmental Protection Agency (USEPA) is to provide real-time forecasting of current 8-hour average ozone exposure over the entire conterminous United States. Such real-time forecasting is now provided as spatial forecast maps of current 8-hour average ozone defined as the average of the previous four hours, current hour, and predictions for the next three hours. Current 8-hour average patterns are updated hourly throughout the day on the EPA-AIRNow web site. The contribution here is to show how we can substantially improve upon current real-time forecasting systems. To enable such forecasting, we introduce a downscaler fusion model based on first differences of real-time monitoring data and numerical model output. The model has a flexible coefficient structure and uses an efficient computational strategy to fit model parameters. Our hybrid computational strategy blends continuous background updated model fitting with real-time predictions. Model validation analyses show that we are achieving very accurate and precise ozone forecasts.

  16. Modeling and Real-Time Simulation of UPFC

    NASA Astrophysics Data System (ADS)

    Kimura, Misao; Takahashi, Choei; Kishibe, Hideto; Miyazaki, Yasuyuki; Noro, Yasuhiro; Iio, Naotaka

    We have developed a digital real time simulator of Power Electronics Controllers, so called FACTS (Flexible AC Transmission Systems) Controllers and/or Custom Power by using MATLABTM/SIMULINKTM and dSPACETM System. This paper describes the modeling and the calculation accuracy of a UPFC (Unified Power Flow Controller) model. Hence the developed simulator operates at a large time step, in order to improve simulation accuracy, a correction processing of the switching delay is implemented into the UPFC model. Calculation accuracy of the real time UPFC model is the same level as EMTDCTM results. We confirm stable operation of the developed UPFC model with connecting a commercial real time digital simulator (RTDSTM).

  17. Real-time dynamic holographic image storage device

    NASA Technical Reports Server (NTRS)

    Lafleur, Sharon S. (Inventor); Montgomery, Raymond C. (Inventor)

    1990-01-01

    A real-time dynamic holographic image storage device uses four-wave mixing in a pair of photorefractive crystals. An oscillation is produced between the crystals which can be maintained indefinitely after the initial object beam is discontinued. The object beam produces an interference pattern in a first crystal to produce phase-conjugated object beam which is directed towards the second crystal. In the second crystal another interference pattern is created which produces a reconstructed object beam. The reconstructed object beam is directed back towards the first crystal. The interference patterns are produced by interaction of the object and phase-conjugated object beam with a read and write beam in each of the crystals. By manipulation of the ratio of the read and write beam intensities in at least one of the crystals, the phase-conjugate or reconstructed object beam output therefrom can be amplified to maintain stable oscillation between the two crystals.

  18. ARTEMIS: Ares Real Time Environments for Modeling, Integration, and Simulation

    NASA Technical Reports Server (NTRS)

    Hughes, Ryan; Walker, David

    2009-01-01

    This slide presentation reviews the use of ARTEMIS in the development and testing of the ARES launch vehicles. Ares Real Time Environment for Modeling, Simulation and Integration (ARTEMIS) is the real time simulation supporting Ares I hardware-in-the-loop (HWIL) testing. ARTEMIS accurately models all Ares/Orion/Ground subsystems which interact with Ares avionics components from pre-launch through orbit insertion The ARTEMIS System integration Lab, and the STIF architecture is reviewed. The functional components of ARTEMIS are outlined. An overview of the models and a block diagram is presented.

  19. Real-time Social Internet Data to Guide Forecasting Models

    SciTech Connect

    Del Valle, Sara Y.

    2016-09-20

    Our goal is to improve decision support by monitoring and forecasting events using social media, mathematical models, and quantifying model uncertainty. Our approach is real-time, data-driven forecasts with quantified uncertainty: Not just for weather anymore. Information flow from human observations of events through an Internet system and classification algorithms is used to produce quantitatively uncertain forecast. In summary, we want to develop new tools to extract useful information from Internet data streams, develop new approaches to assimilate real-time information into predictive models, validate approaches by forecasting events, and our ultimate goal is to develop an event forecasting system using mathematical approaches and heterogeneous data streams.

  20. Real Time Fire Reconnaissance Satellite Monitoring System Failure Model

    NASA Astrophysics Data System (ADS)

    Nino Prieto, Omar Ariosto; Colmenares Guillen, Luis Enrique

    2013-09-01

    In this paper the Real Time Fire Reconnaissance Satellite Monitoring System is presented. This architecture is a legacy of the Detection System for Real-Time Physical Variables which is undergoing a patent process in Mexico. The methodologies for this design are the Structured Analysis for Real Time (SA- RT) [8], and the software is carried out by LACATRE (Langage d'aide à la Conception d'Application multitâche Temps Réel) [9,10] Real Time formal language. The system failures model is analyzed and the proposal is based on the formal language for the design of critical systems and Risk Assessment; AltaRica. This formal architecture uses satellites as input sensors and it was adapted from the original model which is a design pattern for physical variation detection in Real Time. The original design, whose task is to monitor events such as natural disasters and health related applications, or actual sickness monitoring and prevention, as the Real Time Diabetes Monitoring System, among others. Some related work has been presented on the Mexican Space Agency (AEM) Creation and Consultation Forums (2010-2011), and throughout the International Mexican Aerospace Science and Technology Society (SOMECYTA) international congress held in San Luis Potosí, México (2012). This Architecture will allow a Real Time Fire Satellite Monitoring, which will reduce the damage and danger caused by fires which consumes the forests and tropical forests of Mexico. This new proposal, permits having a new system that impacts on disaster prevention, by combining national and international technologies and cooperation for the benefit of humankind.

  1. International journal of computational fluid dynamics real-time prediction of unsteady flow based on POD reduced-order model and particle filter

    NASA Astrophysics Data System (ADS)

    Kikuchi, Ryota; Misaka, Takashi; Obayashi, Shigeru

    2016-04-01

    An integrated method consisting of a proper orthogonal decomposition (POD)-based reduced-order model (ROM) and a particle filter (PF) is proposed for real-time prediction of an unsteady flow field. The proposed method is validated using identical twin experiments of an unsteady flow field around a circular cylinder for Reynolds numbers of 100 and 1000. In this study, a PF is employed (ROM-PF) to modify the temporal coefficient of the ROM based on observation data because the prediction capability of the ROM alone is limited due to the stability issue. The proposed method reproduces the unsteady flow field several orders faster than a reference numerical simulation based on Navier-Stokes equations. Furthermore, the effects of parameters, related to observation and simulation, on the prediction accuracy are studied. Most of the energy modes of the unsteady flow field are captured, and it is possible to stably predict the long-term evolution with ROM-PF.

  2. Waste collection multi objective model with real time traceability data.

    PubMed

    Faccio, Maurizio; Persona, Alessandro; Zanin, Giorgia

    2011-12-01

    Waste collection is a highly visible municipal service that involves large expenditures and difficult operational problems, plus it is expensive to operate in terms of investment costs (i.e. vehicles fleet), operational costs (i.e. fuel, maintenances) and environmental costs (i.e. emissions, noise and traffic congestions). Modern traceability devices, like volumetric sensors, identification RFID (Radio Frequency Identification) systems, GPRS (General Packet Radio Service) and GPS (Global Positioning System) technology, permit to obtain data in real time, which is fundamental to implement an efficient and innovative waste collection routing model. The basic idea is that knowing the real time data of each vehicle and the real time replenishment level at each bin makes it possible to decide, in function of the waste generation pattern, what bin should be emptied and what should not, optimizing different aspects like the total covered distance, the necessary number of vehicles and the environmental impact. This paper describes a framework about the traceability technology available in the optimization of solid waste collection, and introduces an innovative vehicle routing model integrated with the real time traceability data, starting the application in an Italian city of about 100,000 inhabitants. The model is tested and validated using simulation and an economical feasibility study is reported at the end of the paper.

  3. Model Checking Real Time Java Using Java PathFinder

    NASA Technical Reports Server (NTRS)

    Lindstrom, Gary; Mehlitz, Peter C.; Visser, Willem

    2005-01-01

    The Real Time Specification for Java (RTSJ) is an augmentation of Java for real time applications of various degrees of hardness. The central features of RTSJ are real time threads; user defined schedulers; asynchronous events, handlers, and control transfers; a priority inheritance based default scheduler; non-heap memory areas such as immortal and scoped, and non-heap real time threads whose execution is not impeded by garbage collection. The Robust Software Systems group at NASA Ames Research Center has JAVA PATHFINDER (JPF) under development, a Java model checker. JPF at its core is a state exploring JVM which can examine alternative paths in a Java program (e.g., via backtracking) by trying all nondeterministic choices, including thread scheduling order. This paper describes our implementation of an RTSJ profile (subset) in JPF, including requirements, design decisions, and current implementation status. Two examples are analyzed: jobs on a multiprogramming operating system, and a complex resource contention example involving autonomous vehicles crossing an intersection. The utility of JPF in finding logic and timing errors is illustrated, and the remaining challenges in supporting all of RTSJ are assessed.

  4. The Near Real Time Ionospheric Model of Latvia

    NASA Astrophysics Data System (ADS)

    Kaļinka, M.; Zvirgzds, J.; Dobelis, D.; Lazdāns, E.; Reiniks, M.

    2015-11-01

    A highly accurate ionosphere model is necessary to enable a fast and reliable coordinate determination with GNSS in real time. It is a partially ionized atmospheric region ranging up to 1,000 km height, affected by spatial variations, space weather, seasonal and solar cycle dependence. New approaches and algorithms of modelling techniques are sought to provide better solutions in the territory of Latvia. Ionospheric TEC value has large differences in Western Latvia and Eastern Latvia. Actual ionospheric map should be calculated and delivered to the surveyors near real time and published on the WEB. Delivering actual map to rover GNSS devices in a field will provide the surveyors with ionospheric conditions and allow choosing best time for surveying and making geodetic measurements with higher accuracy and reliability.

  5. Eye tracker uncertainty analysis and modelling in real time

    NASA Astrophysics Data System (ADS)

    Fornaser, A.; De Cecco, M.; Leuci, M.; Conci, N.; Daldoss, M.; Armanini, A.; Maule, L.; De Natale, F.; Da Lio, M.

    2017-01-01

    Techniques for tracking the eyes took place since several decades for different applications that range from military, to education, entertainment and clinics. The existing systems are in general of two categories: precise but intrusive or comfortable but less accurate. The idea of this work is to calibrate an eye tracker of the second category. In particular we have estimated the uncertainty both in nominal and in case of variable operating conditions. We took into consideration different influencing factors such as: head movement and rotation, eyes detected, target position on the screen, illumination and objects in front of the eyes. Results proved that the 2D uncertainty can be modelled as a circular confidence interval as far as there is no stable principal directions in both the systematic and the repeatability effects. This confidence region was also modelled as a function of the current working conditions. In this way we can obtain a value of the uncertainty that is a function of the operating condition estimated in real time opening the field to new applications that reconfigure the human machine interface as a function of the operating conditions. Examples can range from option buttons reshape, local zoom dynamically adjusted, speed optimization to regulate interface responsiveness, the possibility to take into account the uncertainty associated to a particular interaction. Furthermore, in the analysis of visual scanning patterns, the resulting Point of Regard maps would be associated with proper confidence levels thus allowing to draw accurate conclusions. We conducted an experimental campaign to estimate and validate the overall modelling procedure obtaining valid results in 86% of the cases.

  6. Modelling the world in real time: how robots engineer information.

    PubMed

    Davison, Andrew J

    2003-12-15

    Programming robots and other autonomous systems to interact with the world in real time is bringing into sharp focus general questions about representation, inference and understanding. These artificial agents use digital computation to interpret the data gleaned from sensors and produce decisions and actions to guide their future behaviour. In a physical system, however, finite computational resources unavoidably impose the need to approximate and make selective use of the information available to reach prompt deductions. Recent research has led to widespread adoption of the methodology of Bayesian inference, which provides the absolute framework to understand this process fully via modelling as informed, fully acknowledged approximation. The performance of modern systems has improved greatly on the heuristic methods of the early days of artificial intelligence. We discuss the general problem of real-time inference and computation, and draw on examples from recent research in computer vision and robotics: specifically visual tracking and simultaneous localization and mapping.

  7. Generalized Sparselet Models for Real-Time Multiclass Object Recognition.

    PubMed

    Song, Hyun Oh; Girshick, Ross; Zickler, Stefan; Geyer, Christopher; Felzenszwalb, Pedro; Darrell, Trevor

    2015-05-01

    The problem of real-time multiclass object recognition is of great practical importance in object recognition. In this paper, we describe a framework that simultaneously utilizes shared representation, reconstruction sparsity, and parallelism to enable real-time multiclass object detection with deformable part models at 5Hz on a laptop computer with almost no decrease in task performance. Our framework is trained in the standard structured output prediction formulation and is generically applicable for speeding up object recognition systems where the computational bottleneck is in multiclass, multi-convolutional inference. We experimentally demonstrate the efficiency and task performance of our method on PASCAL VOC, subset of ImageNet, Caltech101 and Caltech256 dataset.

  8. D Model Visualization Enhancements in Real-Time Game Engines

    NASA Astrophysics Data System (ADS)

    Merlo, A.; Sánchez Belenguer, C.; Vendrell Vidal, E.; Fantini, F.; Aliperta, A.

    2013-02-01

    This paper describes two procedures used to disseminate tangible cultural heritage through real-time 3D simulations providing accurate-scientific representations. The main idea is to create simple geometries (with low-poly count) and apply two different texture maps to them: a normal map and a displacement map. There are two ways to achieve models that fit with normal or displacement maps: with the former (normal maps), the number of polygons in the reality-based model may be dramatically reduced by decimation algorithms and then normals may be calculated by rendering them to texture solutions (baking). With the latter, a LOD model is needed; its topology has to be quad-dominant for it to be converted to a good quality subdivision surface (with consistent tangency and curvature all over). The subdivision surface is constructed using methodologies for the construction of assets borrowed from character animation: these techniques have been recently implemented in many entertainment applications known as "retopology". The normal map is used as usual, in order to shade the surface of the model in a realistic way. The displacement map is used to finish, in real-time, the flat faces of the object, by adding the geometric detail missing in the low-poly models. The accuracy of the resulting geometry is progressively refined based on the distance from the viewing point, so the result is like a continuous level of detail, the only difference being that there is no need to create different 3D models for one and the same object. All geometric detail is calculated in real-time according to the displacement map. This approach can be used in Unity, a real-time 3D engine originally designed for developing computer games. It provides a powerful rendering engine, fully integrated with a complete set of intuitive tools and rapid workflows that allow users to easily create interactive 3D contents. With the release of Unity 4.0, new rendering features have been added, including Direct

  9. A system for EPID-based real-time treatment delivery verification during dynamic IMRT treatment

    SciTech Connect

    Fuangrod, Todsaporn; Woodruff, Henry C.; O’Connor, Daryl J.; Uytven, Eric van; McCurdy, Boyd M. C.; Kuncic, Zdenka; Greer, Peter B.

    2013-09-15

    Purpose: To design and develop a real-time electronic portal imaging device (EPID)-based delivery verification system for dynamic intensity modulated radiation therapy (IMRT) which enables detection of gross treatment delivery errors before delivery of substantial radiation to the patient.Methods: The system utilizes a comprehensive physics-based model to generate a series of predicted transit EPID image frames as a reference dataset and compares these to measured EPID frames acquired during treatment. The two datasets are using MLC aperture comparison and cumulative signal checking techniques. The system operation in real-time was simulated offline using previously acquired images for 19 IMRT patient deliveries with both frame-by-frame comparison and cumulative frame comparison. Simulated error case studies were used to demonstrate the system sensitivity and performance.Results: The accuracy of the synchronization method was shown to agree within two control points which corresponds to approximately ∼1% of the total MU to be delivered for dynamic IMRT. The system achieved mean real-time gamma results for frame-by-frame analysis of 86.6% and 89.0% for 3%, 3 mm and 4%, 4 mm criteria, respectively, and 97.9% and 98.6% for cumulative gamma analysis. The system can detect a 10% MU error using 3%, 3 mm criteria within approximately 10 s. The EPID-based real-time delivery verification system successfully detected simulated gross errors introduced into patient plan deliveries in near real-time (within 0.1 s).Conclusions: A real-time radiation delivery verification system for dynamic IMRT has been demonstrated that is designed to prevent major mistreatments in modern radiation therapy.

  10. Casualty modeling for real-time medical training.

    PubMed

    Chi, D M; Clarke, J R; Webber, B L; Badler, N I

    1996-01-01

    We present a model for simulating casualties in virtual environments for real-time medical training. It allows a user to choose diagnostic and therapeutic actions to carry out on a simulated casualty who will manifest appropriate physiological, behavioral, and physical responses. Currently, the user or a "stealth instructor" can specify one or more injuries that the casualty has sustained. The model responds by continuously determining the state of the casualty, responding appropriately to medical assessment and treatment procedures. So far, we have modeled four medical conditions and over 20 procedures. The model has been designed to handle the addition of other injuries and medical procedures.

  11. Application of real time systems to the analysis of neuronal dynamics

    NASA Astrophysics Data System (ADS)

    Cymbalyuk, Gennady; Shilnikov, Andrey

    2008-03-01

    Neurons exhibit various activity regimes and transitions in between. The central pattern generator controlling the leech's heartbeat contains identified pairs of mutually inhibitory neurons (Calabrese et al. 1995). We describe real time systems approaches to the analysis of their activity. The hybrid system consists of a living neuron and a model neuron (or an artificial silicon neuron) interacting in the real time. Dynamic clamp is used to implement artificial ionic currents and synapses in the system (Sharp et al. 1993). Our study determines the mechanisms underlying and regulating bursting activity, based on intrinsic membrane dynamics and network interactions. The complexity of endogenous dynamics originates from the diversity of ionic currents operating on different time scales. Hybrid system analysis and slow-fast dynamical systems analysis have been combined in our studies of bursting, its origin and transformations in heart interneurons both as single cells and in the mutually inhibitory configuration.

  12. A Real-Time Groundwater Management Model Using Data Assimilation

    NASA Astrophysics Data System (ADS)

    Cheng, W.; Putti, M.; Kendall, D.; Yeh, W. W.

    2009-12-01

    This study develops a groundwater management model for real time operation of an aquifer system. A groundwater flow model is allied with a nudging data assimilation algorithm that reduces the forecast error, minimizes the risk of system failure, and improves management strategies. The nudging algorithm treats the unknown private pumping as an additional sink term in the groundwater flow equations and provides a consistently physical interpretation for pumping rates identification. The response of the groundwater simulation model due to pumping/injection is represented by a response matrix which is generated by the influence coefficient method. The response matrix with a much smaller dimension (referred to as the reduced simulation model) is directly embedded in the management model as a part of the constraint set. Additionally, the influence coefficient method is utilized to include the nudging effect as additional terms in the reduced simulation model. The management model optimizes monthly operational policy for 12 months into the future with given initial condition and system constraints. We apply the developed management model to the Aquifer Storage and Recovery (ASR) project of the Las Posas Groundwater Basin in southern California. We consider both the injection and pumping scenarios. In the case studies, six unknown pumping rates from private wells are estimated using measured heads from four observation wells. The management model determines the optimal operational strategies using the information provided by nudging and is updated at the beginning of each month when new head observations become available. We also discuss the utility, accuracy, and efficiency of the proposed management model for real time operation.

  13. Dynamic multiplanar real time ultrasound guided infraclavicular subclavian vein catheterization.

    PubMed

    Zhong, Xin; Hamill, Mark; Collier, Bryan; Bradburn, Eric; Ferrara, John

    2015-06-01

    Ultrasound guided vascular access has been well-characterized as a safe and effective technique for internal jugular and femoral vein catheterization. However, there is limited experience with the use of ultrasound to access the infraclavicular subclavian vein. Multiple ultrasound techniques do exist to identify the subclavian vein, but real time access is limited by vessel identification in a single planar view. To overcome this limitation, a novel technique of ultrasound guided infraclavicular subclavian vein catheterization using a real time multiplanar approach has been developed. The initial experience with this approach is described. A single surgeon used combined oblique, transverse, and longitudinal views along with Doppler color flow images to both define the infraclavicular anatomy and to obtain subclavian vein access in 42 adult patients (20 M/22 F and 22 L/20 R) with a mean body mass index of 29.2 (range = 18.9-55.4). Chest x-ray was obtained to confirm position and to rule out pneumothorax. Subclavian vein cannulation was achieved in 100 per cent of patients; subsequent catheterization was successful in 92.9 per cent. The number of attempts required for cannulation averaged 1.3 (range = 1-5), and decreased after a five patient learning curve. No patient developed a pneumothorax, hematoma, or cannula malposition. Ultrasound guided multiplanar infraclavicular subclavian vein access appears to be a safe and effective adjunct for central line placement.

  14. Real Time Land-Surface Hydrologic Modeling Over Continental US

    NASA Technical Reports Server (NTRS)

    Houser, Paul R.

    1998-01-01

    The land surface component of the hydrological cycle is fundamental to the overall functioning of the atmospheric and climate processes. Spatially and temporally variable rainfall and available energy, combined with land surface heterogeneity cause complex variations in all processes related to surface hydrology. The characterization of the spatial and temporal variability of water and energy cycles are critical to improve our understanding of land surface-atmosphere interaction and the impact of land surface processes on climate extremes. Because the accurate knowledge of these processes and their variability is important for climate predictions, most Numerical Weather Prediction (NWP) centers have incorporated land surface schemes in their models. However, errors in the NWP forcing accumulate in the surface and energy stores, leading to incorrect surface water and energy partitioning and related processes. This has motivated the NWP to impose ad hoc corrections to the land surface states to prevent this drift. A proposed methodology is to develop Land Data Assimilation schemes (LDAS), which are uncoupled models forced with observations, and not affected by NWP forcing biases. The proposed research is being implemented as a real time operation using an existing Surface Vegetation Atmosphere Transfer Scheme (SVATS) model at a 40 km degree resolution across the United States to evaluate these critical science questions. The model will be forced with real time output from numerical prediction models, satellite data, and radar precipitation measurements. Model parameters will be derived from the existing GIS vegetation and soil coverages. The model results will be aggregated to various scales to assess water and energy balances and these will be validated with various in-situ observations.

  15. A Circuit Model of Real Time Human Body Hydration.

    PubMed

    Asogwa, Clement Ogugua; Teshome, Assefa K; Collins, Stephen F; Lai, Daniel T H

    2016-06-01

    Changes in human body hydration leading to excess fluid losses or overload affects the body fluid's ability to provide the necessary support for healthy living. We propose a time-dependent circuit model of real-time human body hydration, which models the human body tissue as a signal transmission medium. The circuit model predicts the attenuation of a propagating electrical signal. Hydration rates are modeled by a time constant τ, which characterizes the individual specific metabolic function of the body part measured. We define a surrogate human body anthropometric parameter θ by the muscle-fat ratio and comparing it with the body mass index (BMI), we find theoretically, the rate of hydration varying from 1.73 dB/min, for high θ and low τ to 0.05 dB/min for low θ and high τ. We compare these theoretical values with empirical measurements and show that real-time changes in human body hydration can be observed by measuring signal attenuation. We took empirical measurements using a vector network analyzer and obtained different hydration rates for various BMI, ranging from 0.6 dB/min for 22.7 [Formula: see text] down to 0.04 dB/min for 41.2 [Formula: see text]. We conclude that the galvanic coupling circuit model can predict changes in the volume of the body fluid, which are essential in diagnosing and monitoring treatment of body fluid disorder. Individuals with high BMI would have higher time-dependent biological characteristic, lower metabolic rate, and lower rate of hydration.

  16. A Real-Time Assimilative Model for IRI

    NASA Astrophysics Data System (ADS)

    Reinisch, B. W.; Huang, X.; Galkin, I.; Bilitza, D.

    2012-04-01

    Ionospheric models are mostly unable to correctly predict the effects of space weather events and atmospheric disturbances on the ionosphere. This is especially true for the International Reference Ionosphere (IRI) which by design is a monthly median (climatological) model [Bilitza et al., 2011]. We propose a Real-Time Assimilative Model "RTAM" for IRI that is ingesting, initially, the available real-time Digisonde GIRO [Reinisch and Galkin, 2011] data streams: foF2/hmF2, MUF3000F2, foF1/hmF1, and foE/hmF2 [Galkin et al., 2011]. Deviations of these characteristics, especially foF2, from the monthly median values are the main cause for errors in the IRI model prediction. The assimilative modeling will provide a high-resolution, global picture of the ionospheric response to various short-term events observed during periods of storm activity or the impact of gravity waves coupling the ionosphere to the lower atmosphere, including timelines of the vertical restructuring of the plasma distribution. GIRO currently provides reliable real-time data from 42 stations at a cadence of 15 min or 5 min. The number of stations is rapidly growing and is likely to soon be complemented by satellite borne topside sounders. IRI uses the characteristics predictions based on CCIR/URSI maps of coefficients. The diurnal variation of the foF2 characteristic, for example, is presented by the Fourier series Σ6 foF 2(T, φ,λ,χ) = a0(φ,λ,χ)+ (an(φ,λ,χ)cosnT + bn(φ,λ,χ)sin nT), n=1 where T is Universal Time in hours, and φ, λ, χ are the geographic latitude, longitude, and modified dip latitude, respectively. The coefficients an are in turn expanded as functions φ, λ, χ resulting in a set of 24 global maps of 988 coefficients each, one for each month of the year and for two levels of solar activity, R12=10 and 100, where R12 is the 12-month running-mean of the monthly sunspot number Rm (2*12*988 = 23,712 coefficients in all) [ITU-R, 2011]. For a given point in time, 988

  17. Real-time dynamic simulator for the Topaz II reactor power system

    SciTech Connect

    Kwok, K.S.

    1994-10-01

    A dynamic simulator of the TOPAZ II reactor system has been developed for the Nuclear Electric Propulsion Space Test Program. The simulator is a self-contained IBM-PC compatible based system that executes at a speed faster than real-time. The simulator combines first-principle modeling and empirical correlations in its algorithm to attain the modeling accuracy and computational through-put that are required for real-time execution. The overall execution time of the simulator for each time step is 15 ms when no data is written to the disk, and 18 ms when nine double precision data points are written to the disk once in every time step. The simulation program has been tested and it is able to handle a step decrease of $8 worth of reactivity. It also provides simulation of fuel, emitter, collector, stainless steel, and ZrH moderator failures. Presented in this paper are the models used in the calculations, a sample simulation session, and a discussion of the performance and limitations of the simulator. The simulator has been found to provide realistic real-time dynamic response of the TOPAZ II reactor system under both normal and causality conditions.

  18. Math modeling and computer mechanization for real time simulation of rotary-wing aircraft

    NASA Technical Reports Server (NTRS)

    Howe, R. M.

    1979-01-01

    Mathematical modeling and computer mechanization for real time simulation of rotary wing aircraft is discussed. Error analysis in the digital simulation of dynamic systems, such as rotary wing aircraft is described. The method for digital simulation of nonlinearities with discontinuities, such as exist in typical flight control systems and rotor blade hinges, is discussed.

  19. Discrete-event requirements model for sensor fusion to provide real-time diagnostic feedback

    NASA Astrophysics Data System (ADS)

    Rokonuzzaman, Mohd; Gosine, Raymond G.

    1998-06-01

    Minimally-invasive surgical techniques reduce the size of the access corridor and affected zones resulting in limited real-time perceptual information available to the practitioners. A real-time feedback system is required to offset deficiencies in perceptual information. This feedback system acquires data from multiple sensors and fuses these data to extract pertinent information within defined time windows. To perform this task, a set of computing components interact with each other resulting in a discrete event dynamic system. In this work, a new discrete event requirements model for sensor fusion has been proposed to ensure logical and temporal correctness of the operation of the real-time diagnostic feedback system. This proposed scheme models system requirements as a Petri net based discrete event dynamic machine. The graphical representation and quantitative analysis of this model has been developed. Having a natural graphical property, this Petri net based model enables the requirements engineer to communicate intuitively with the client to avoid faults in the early phase of the development process. The quantitative analysis helps justify the logical and temporal correctness of the operation of the system. It has been shown that this model can be analyzed to check the presence of deadlock, reachability, and repetitiveness of the operation of the sensor fusion system. This proposed novel technique to model the requirements of sensor fusion as a discrete event dynamic system has the potential to realize highly reliable real-time diagnostic feedback system for many applications, such as minimally invasive instrumentation.

  20. Application of linear programming techniques for controlling linear dynamic plants in real time

    NASA Astrophysics Data System (ADS)

    Gabasov, R.; Kirillova, F. M.; Ha, Vo Thi Thanh

    2016-03-01

    The problem of controlling a linear dynamic plant in real time given its nondeterministic model and imperfect measurements of the inputs and outputs is considered. The concepts of current distributions of the initial state and disturbance parameters are introduced. The method for the implementation of disclosable loop using the separation principle is described. The optimal control problem under uncertainty conditions is reduced to the problems of optimal observation, optimal identification, and optimal control of the deterministic system. To extend the domain where a solution to the optimal control problem under uncertainty exists, a two-stage optimal control method is proposed. Results are illustrated using a dynamic plant of the fourth order.

  1. Real-time estimation of lead-acid battery parameters: A dynamic data-driven approach

    NASA Astrophysics Data System (ADS)

    Li, Yue; Shen, Zheng; Ray, Asok; Rahn, Christopher D.

    2014-12-01

    This short paper presents a recently reported dynamic data-driven method, Symbolic Dynamic Filtering (SDF), for real-time estimation of the state-of-health (SOH) and state-of-charge (SOC) in lead-acid batteries, as an alternative to model-based analysis techniques. In particular, SOC estimation relies on a k-NN regression algorithm while SOH estimation is obtained from the divergence between extracted features. The results show that the proposed data-driven method successfully distinguishes battery voltage responses under different SOC and SOH situations.

  2. Real-time electron dynamics simulation of two-electron transfer reactions induced by nuclear motion

    NASA Astrophysics Data System (ADS)

    Suzuki, Yasumitsu; Yamashita, Koichi

    2012-04-01

    Real-time electron dynamics of two-electron transfer reactions induced by nuclear motion is calculated by three methods: the numerically exact propagation method, the time-dependent Hartree (TDH) method and the Ehrenfest method. We find that, as long as the nuclei move as localized wave packets, the TDH and Ehrenfest methods can reproduce the exact electron dynamics of a simple charge transfer reaction model containing two electrons qualitatively well, even when nonadiabatic transitions between adiabatic states occur. In particular, both methods can reproduce the cases where a complete two-electron transfer reaction occurs and those where it does not occur.

  3. Designers Workbench: Towards Real-Time Immersive Modeling

    SciTech Connect

    Kuester, F; Duchaineau, M A; Hamann, B; Joy, K I; Ma, K L

    2001-10-03

    This paper introduces the DesignersWorkbench, a semi-immersive virtual environment for two-handed modeling, sculpting and analysis tasks. The paper outlines the fundamental tools, design metaphors and hardware components required for an intuitive real-time modeling system. As companies focus on streamlining productivity to cope with global competition, the migration to computer-aided design (CAD), computer-aided manufacturing (CAM), and computer-aided engineering (CAE) systems has established a new backbone of modern industrial product development. However, traditionally a product design frequently originates from a clay model that, after digitization, forms the basis for the numerical description of CAD primitives. The DesignersWorkbench aims at closing this technology or ''digital gap'' experienced by design and CAD engineers by transforming the classical design paradigm into its filly integrated digital and virtual analog allowing collaborative development in a semi-immersive virtual environment. This project emphasizes two key components from the classical product design cycle: freeform modeling and analysis. In the freeform modeling stage, content creation in the form of two-handed sculpting of arbitrary objects using polygonal, volumetric or mathematically defined primitives is emphasized, whereas the analysis component provides the tools required for pre- and post-processing steps for finite element analysis tasks applied to the created models.

  4. Real-time application of the drag based model

    NASA Astrophysics Data System (ADS)

    Žic, Tomislav; Temmer, Manuela; Vršnak, Bojan

    2016-04-01

    The drag-based model (DBM) is an analytical model which is usually used for calculating kinematics of coronal mass ejections (CMEs) in the interplanetary space, prediction of the CME arrival times and impact speeds at arbitrary targets in the heliosphere. The main assumption of the model is that beyond a distance of about 20 solar radii from the Sun, the drag is dominant in the interplanetary space. The previous version of DBM relied on the rough assumption of averaged, unperturbed and constant environmental conditions as well as constant CME properties throughout the entire interplanetary CME propagation. The continuation of our work consists of enhancing the model into a form which uses a time dependent and perturbed environment without constraints on CME properties and distance forecasting. The extension provides the possibility of application in various scenarios, such as automatic least-square fitting on initial CME kinematic data suitable for a real-time forecasting of CME kinematics, or embedding the DBM into pre-calculated interplanetary ambient conditions provided by advanced numerical simulations (for example, codes of ENLIL, EUHFORIA, etc.). A demonstration of the enhanced DBM is available on the web-site: http://www.geof.unizg.hr/~tzic/dbm.html. We acknowledge the support of European Social Fund under the "PoKRet" project.

  5. Real-time simulation model of the HL-20 lifting body

    NASA Astrophysics Data System (ADS)

    Jackson, E. Bruce; Cruz, Christopher I.; Ragsdale, W. A.

    1992-07-01

    A proposed manned spacecraft design, designated the HL-20, has been under investigation at Langley Research Center. Included in that investigation are flight control design and flying qualities studies utilizing a man-in-the-loop real-time simulator. This report documents the current real-time simulation model of the HL-20 lifting body vehicle, known as version 2.0, presently in use at NASA Langley Research Center. Included are data on vehicle aerodynamics, inertias, geometries, guidance and control laws, and cockpit displays and controllers. In addition, trim case and dynamic check case data is provided. The intent of this document is to provide the reader with sufficient information to develop and validate an equivalent simulation of the HL-20 for use in real-time or analytical studies.

  6. Real-time simulation model of the HL-20 lifting body

    NASA Technical Reports Server (NTRS)

    Jackson, E. Bruce; Cruz, Christopher I.; Ragsdale, W. A.

    1992-01-01

    A proposed manned spacecraft design, designated the HL-20, has been under investigation at Langley Research Center. Included in that investigation are flight control design and flying qualities studies utilizing a man-in-the-loop real-time simulator. This report documents the current real-time simulation model of the HL-20 lifting body vehicle, known as version 2.0, presently in use at NASA Langley Research Center. Included are data on vehicle aerodynamics, inertias, geometries, guidance and control laws, and cockpit displays and controllers. In addition, trim case and dynamic check case data is provided. The intent of this document is to provide the reader with sufficient information to develop and validate an equivalent simulation of the HL-20 for use in real-time or analytical studies.

  7. Development of a dynamic model for real-time determination of membrane-bound acetylcholinesterase activity upon perfusion with inhibitors and reactivators.

    PubMed

    Eckert, Saskia; Eyer, Peter; Mückter, Harald; Worek, Franz

    2006-07-28

    Quantitative predictions of the course of acetylcholinesterase (AChE) activity, following interference of inhibitors and reactivators, are usually obscured by the time-dependent changes of all reaction partners. To mimic these dynamics we developed an in vitro model. Immobilized human erythrocyte ghosts in a bioreactor were continuously perfused while AChE activity was monitored by a modified Ellman method. The perfusion system consisted of two HPLC pumps with integrated quaternary low-pressure gradient formers that were programmed by a computer using commercial HPLC software. The combined eluates passed a particle filter (Millex-GS, 0.22 microm) containing a thin layer of erythrocytes that was immersed in a temperature-controlled water bath. The effluent passed a flow cell in a UV-vis detector, the signal of which was digitized, written to disc and calculated with curve fitting programs. AChE activity decreased by 3.4% within 2.5 h. The day-to-day variation of the freshly prepared bioreactor using the same enzyme source was +/-3.3%. Residual activity of 0.2% marked the limit of quantification. Following perfusion with paraoxon, pseudo first-order rate constants of inhibition were established that did not differ from results obtained in conventional assays. The same holds true for reactivation with obidoxime. The set-up presented allows freely programmable time-dependent changes of up to eight solvents to mimic pharmacokinetic profiles without accumulation of products. Due to some hysteresis in the system, reaction half-lives should be >3 min and concentration changes in critical compounds should exceed half-lives of 5 min. Otherwise, the system offers much flexibility and operates with high precision.

  8. Real-Time, Holographic, Dynamic Image-Storage Device

    NASA Technical Reports Server (NTRS)

    Montgomery, Raymond C.; Lafleur, Sharon S.

    1995-01-01

    Solid-state device developed for high-speed acquisition, dynamic storage, and amplification of three-dimensional holographic images. Holograms generated via four-wave mixing in two or more photorefractive crystals (or subelements of single crystal) to create single-crystal or multicrystal oscillator. Apparatus provides dynamic storage of holographic image of object after electronic shutter closed to turn off object beam. Provides capability to store, amplify, process, and transmit time-varying, two-dimensional, spatial information. Developments include sensors, actuators, and optical computers operating at speeds on order of speed of light. Potential in applications in which need for high-speed acquisition and storage of three-dimensional holographic images.

  9. Real-time dynamics of lattice gauge theories with a few-qubit quantum computer

    NASA Astrophysics Data System (ADS)

    Martinez, Esteban A.; Muschik, Christine A.; Schindler, Philipp; Nigg, Daniel; Erhard, Alexander; Heyl, Markus; Hauke, Philipp; Dalmonte, Marcello; Monz, Thomas; Zoller, Peter; Blatt, Rainer

    2016-06-01

    Gauge theories are fundamental to our understanding of interactions between the elementary constituents of matter as mediated by gauge bosons. However, computing the real-time dynamics in gauge theories is a notorious challenge for classical computational methods. This has recently stimulated theoretical effort, using Feynman’s idea of a quantum simulator, to devise schemes for simulating such theories on engineered quantum-mechanical devices, with the difficulty that gauge invariance and the associated local conservation laws (Gauss laws) need to be implemented. Here we report the experimental demonstration of a digital quantum simulation of a lattice gauge theory, by realizing (1 + 1)-dimensional quantum electrodynamics (the Schwinger model) on a few-qubit trapped-ion quantum computer. We are interested in the real-time evolution of the Schwinger mechanism, describing the instability of the bare vacuum due to quantum fluctuations, which manifests itself in the spontaneous creation of electron-positron pairs. To make efficient use of our quantum resources, we map the original problem to a spin model by eliminating the gauge fields in favour of exotic long-range interactions, which can be directly and efficiently implemented on an ion trap architecture. We explore the Schwinger mechanism of particle-antiparticle generation by monitoring the mass production and the vacuum persistence amplitude. Moreover, we track the real-time evolution of entanglement in the system, which illustrates how particle creation and entanglement generation are directly related. Our work represents a first step towards quantum simulation of high-energy theories using atomic physics experiments—the long-term intention is to extend this approach to real-time quantum simulations of non-Abelian lattice gauge theories.

  10. Real-time dynamics of lattice gauge theories with a few-qubit quantum computer.

    PubMed

    Martinez, Esteban A; Muschik, Christine A; Schindler, Philipp; Nigg, Daniel; Erhard, Alexander; Heyl, Markus; Hauke, Philipp; Dalmonte, Marcello; Monz, Thomas; Zoller, Peter; Blatt, Rainer

    2016-06-23

    Gauge theories are fundamental to our understanding of interactions between the elementary constituents of matter as mediated by gauge bosons. However, computing the real-time dynamics in gauge theories is a notorious challenge for classical computational methods. This has recently stimulated theoretical effort, using Feynman's idea of a quantum simulator, to devise schemes for simulating such theories on engineered quantum-mechanical devices, with the difficulty that gauge invariance and the associated local conservation laws (Gauss laws) need to be implemented. Here we report the experimental demonstration of a digital quantum simulation of a lattice gauge theory, by realizing (1 + 1)-dimensional quantum electrodynamics (the Schwinger model) on a few-qubit trapped-ion quantum computer. We are interested in the real-time evolution of the Schwinger mechanism, describing the instability of the bare vacuum due to quantum fluctuations, which manifests itself in the spontaneous creation of electron-positron pairs. To make efficient use of our quantum resources, we map the original problem to a spin model by eliminating the gauge fields in favour of exotic long-range interactions, which can be directly and efficiently implemented on an ion trap architecture. We explore the Schwinger mechanism of particle-antiparticle generation by monitoring the mass production and the vacuum persistence amplitude. Moreover, we track the real-time evolution of entanglement in the system, which illustrates how particle creation and entanglement generation are directly related. Our work represents a first step towards quantum simulation of high-energy theories using atomic physics experiments-the long-term intention is to extend this approach to real-time quantum simulations of non-Abelian lattice gauge theories.

  11. Real-time visualization of dynamic particle contact failures

    NASA Astrophysics Data System (ADS)

    Parab, Niranjan D.; Hudspeth, Matthew; Claus, Ben; Guo, Zherui; Sun, Tao; Fezzaa, Kamel; Chen, Weinong W.

    2017-01-01

    Granular materials are widely used to resist impact and blast. Under these dynamic loadings, the constituent particles in the granular system fracture. To study the fracture mechanisms in brittle particles under dynamic compressive loading, a high speed X-ray phase contrast imaging setup was synchronized with a Kolsky bar apparatus. Controlled compressive loading was applied on two contacting particles using the Kolsky bar apparatus and fracture process was captured using the high speed X-ray imaging setup. Five different particles were investigated: soda-lime glass, polycrystalline silica (silicon dioxide), polycrystalline silicon, barium titanate glass, and yttrium stabilized zirconia. For both soda lime glass and polycrystalline silica particles, one of the particles fragmented explosively, thus breaking into many small pieces. For Silicon and barium titanate glass particles, a finite number of cracks were observed in one of the particles causing it to fracture. For yttrium stabilized zirconia particles, a single meridonial crack developed in one of the particles, breaking it into two parts.

  12. Towards Real-Time Global Localization in Dynamic Unstructured Environments

    NASA Astrophysics Data System (ADS)

    Tanaka, Kanji; Kondo, Eiji

    Global localization is the problem in which a mobile robot has to estimate the self-position with respect to an a priori given map as it navigates without using any a priori knowledge of the initial self-position. Previous studies on global localization mainly focused on static environments, where the a priori map is almost correct. On the other hand, in dynamic environments, there are several sources of computational complexity. For example, not only the self-position but also the map should be estimated due to the map errors. The main contribution of this paper is to address such computational complexity by decomposing our global localization problem into two smaller subproblems, and solving the subproblems in a practical computation time. Also, we demonstrate the robustness and the efficiency of the proposed method in various large and complex environments.

  13. Dynamic simulation and optimal real-time operation of CHP systems for buildings

    NASA Astrophysics Data System (ADS)

    Cho, Hee Jin

    Combined Cooling, Heating, and Power (CHP) systems have been widely recognized as a key alternative for electric and thermal energy generation because of their outstanding energy efficiency, reduced environmental emissions, and relative independence from centralized power grids. The systems provide simultaneous onsite or near-site electric and thermal energy generation in a single, integrated package. As CHP becomes increasingly popular worldwide and its total capacity increases rapidly, the research on the topics of CHP performance assessment, design, and operational strategy become increasingly important. Following this trend of research activities to improve energy efficiency, environmental emissions, and operational cost, this dissertation focuses on the following aspects: (a) performance evaluation of a CHP system using a transient simulation model; (b) development of a dynamic simulation model of a power generation unit that can be effectively used in transient simulations of CHP systems; (c) investigation of real-time operation of CHP systems based on optimization with respect to operational cost, primary energy consumption, and carbon dioxide emissions; and (d) development of optimal supervisory feed-forward control that can provide realistic real-time operation of CHP systems with electric and thermal energy storages using short-term weather forecasting. The results from a transient simulation of a CHP system show that technical and economical performance can be readily evaluated using the transient model and that the design, component selection, and control of a CHP system can be improved using this model. The results from the case studies using optimal real-time operation strategies demonstrate that CHP systems with an energy dispatch algorithm have the potential to yield savings in operational cost, primary energy consumption, and carbon dioxide emissions with respect to a conventional HVAC system. Finally, the results from the case study using a

  14. Real-time performance modeling of (3G) UMTS system

    NASA Astrophysics Data System (ADS)

    Badrinath, R.; Mitra, Abhijit; Sinha, Nishant; Mukherjee, Niloy

    2001-11-01

    Universal Mobile Telecommunications System (UMTS) wireless technologies is a proposed standardization as a part of 3GPP solutions to satisfy IMT-2000 requirements. It is based on wideband CDMA technology. It will provide full coverage and mobility for 144 Kb/s, preferably 384 Kb/s and limited coverage and mobility for 2 Mb/s. It proposes high spectrum efficiency compared to existing systems, handling of different QOS profiles and high flexibility to introduce new service. In this paper, we present our work on modeling of the access stratum (AS) on the User Equipment/Mobile Termination (UE/MT) side of the radio (Uu) interface in accordance with 3GPP UMTS standards. The AS has the following sub-layers: Medium Access Control/Radio Link Control (MAC/RLC), Broadcast Multicast Control (BMC), Packet Data Convergence Protocol (PDCP) and Radio Resource Control (RRC). We have assumed the number of transport channels interfacing the AS MAC sub layer and the physical layer to be eight. The data rates have been assumed to be 384 Kb/s per transport channel both in uplink and downlink. Processing in each sub-layer with corresponding delays and interaction between adjacent sublayers having timing restrictions or rate restrictions have been analyzed. Interaction of the upper sub-layers with the non-access stratum (NAS) and interaction between peer AS sub-layers in the UE and the UTRAN have also been incorporated. A real time priority based scheduler process has been specified to honor the time restrictions e.g. the Transmission Time Intervals (TTI) of the channels. The system has been simulated on Virtual Silicon, a C based SDL tool and evaluated on CR16C architecture family using CR16C debugger, both developed by National Semi Conductor Corp., U.S.A.

  15. Analysis of real-time reservoir monitoring : reservoirs, strategies, & modeling.

    SciTech Connect

    Mani, Seethambal S.; van Bloemen Waanders, Bart Gustaaf; Cooper, Scott Patrick; Jakaboski, Blake Elaine; Normann, Randy Allen; Jennings, Jim; Gilbert, Bob; Lake, Larry W.; Weiss, Chester Joseph; Lorenz, John Clay; Elbring, Gregory Jay; Wheeler, Mary Fanett; Thomas, Sunil G.; Rightley, Michael J.; Rodriguez, Adolfo; Klie, Hector; Banchs, Rafael; Nunez, Emilio J.; Jablonowski, Chris

    2006-11-01

    The project objective was to detail better ways to assess and exploit intelligent oil and gas field information through improved modeling, sensor technology, and process control to increase ultimate recovery of domestic hydrocarbons. To meet this objective we investigated the use of permanent downhole sensors systems (Smart Wells) whose data is fed real-time into computational reservoir models that are integrated with optimized production control systems. The project utilized a three-pronged approach (1) a value of information analysis to address the economic advantages, (2) reservoir simulation modeling and control optimization to prove the capability, and (3) evaluation of new generation sensor packaging to survive the borehole environment for long periods of time. The Value of Information (VOI) decision tree method was developed and used to assess the economic advantage of using the proposed technology; the VOI demonstrated the increased subsurface resolution through additional sensor data. Our findings show that the VOI studies are a practical means of ascertaining the value associated with a technology, in this case application of sensors to production. The procedure acknowledges the uncertainty in predictions but nevertheless assigns monetary value to the predictions. The best aspect of the procedure is that it builds consensus within interdisciplinary teams The reservoir simulation and modeling aspect of the project was developed to show the capability of exploiting sensor information both for reservoir characterization and to optimize control of the production system. Our findings indicate history matching is improved as more information is added to the objective function, clearly indicating that sensor information can help in reducing the uncertainty associated with reservoir characterization. Additional findings and approaches used are described in detail within the report. The next generation sensors aspect of the project evaluated sensors and packaging

  16. Real-time multi-model decadal climate predictions

    NASA Astrophysics Data System (ADS)

    Smith, Doug M.; Scaife, Adam A.; Boer, George J.; Caian, Mihaela; Doblas-Reyes, Francisco J.; Guemas, Virginie; Hawkins, Ed; Hazeleger, Wilco; Hermanson, Leon; Ho, Chun Kit; Ishii, Masayoshi; Kharin, Viatcheslav; Kimoto, Masahide; Kirtman, Ben; Lean, Judith; Matei, Daniela; Merryfield, William J.; Müller, Wolfgang A.; Pohlmann, Holger; Rosati, Anthony; Wouters, Bert; Wyser, Klaus

    2013-12-01

    We present the first climate prediction of the coming decade made with multiple models, initialized with prior observations. This prediction accrues from an international activity to exchange decadal predictions in near real-time, in order to assess differences and similarities, provide a consensus view to prevent over-confidence in forecasts from any single model, and establish current collective capability. We stress that the forecast is experimental, since the skill of the multi-model system is as yet unknown. Nevertheless, the forecast systems used here are based on models that have undergone rigorous evaluation and individually have been evaluated for forecast skill. Moreover, it is important to publish forecasts to enable open evaluation, and to provide a focus on climate change in the coming decade. Initialized forecasts of the year 2011 agree well with observations, with a pattern correlation of 0.62 compared to 0.31 for uninitialized projections. In particular, the forecast correctly predicted La Niña in the Pacific, and warm conditions in the north Atlantic and USA. A similar pattern is predicted for 2012 but with a weaker La Niña. Indices of Atlantic multi-decadal variability and Pacific decadal variability show no signal beyond climatology after 2015, while temperature in the Niño3 region is predicted to warm slightly by about 0.5 °C over the coming decade. However, uncertainties are large for individual years and initialization has little impact beyond the first 4 years in most regions. Relative to uninitialized forecasts, initialized forecasts are significantly warmer in the north Atlantic sub-polar gyre and cooler in the north Pacific throughout the decade. They are also significantly cooler in the global average and over most land and ocean regions out to several years ahead. However, in the absence of volcanic eruptions, global temperature is predicted to continue to rise, with each year from 2013 onwards having a 50 % chance of exceeding the

  17. A Provenance Model for Real-Time Water Information Systems

    NASA Astrophysics Data System (ADS)

    Liu, Q.; Bai, Q.; Zednik, S.; Taylor, P.; Fox, P. A.; Taylor, K.; Kloppers, C.; Peters, C.; Terhorst, A.; West, P.; Compton, M.; Shu, Y.; Provenance Management Team

    2010-12-01

    Generating hydrological data products, such as flow forecasts, involves complex interactions among instruments, data simulation models, computational facilities and data providers. Correct interpretation of the data produced at various stages requires good understanding of how data was generated or processed. Provenance describes the lineage of a data product. Making provenance information accessible to hydrologists and decision makers not only helps to determine the data’s value, accuracy and authorship, but also enables users to determine the trustworthiness of the data product. In the water domain, WaterML2 [1] is an emerging standard which describes an information model and format for the publication of water observations data in XML. The W3C semantic sensor network incubator group (SSN-XG) [3] is producing ontologies for the description of sensor configurations. By integrating domain knowledge of this kind into the provenance information model, the integrated information model will enable water domain researchers and water resource managers to better analyse how observations and derived data products were generated. We first introduce the Proof Mark Language (PML2) [2], WaterML2 and the SSN-XG sensor ontology as the proposed provenance representation formalism. Then we describe some initial implementations how these standards could be integrated to represent the lineage of water information products. Finally we will highlight how the provenance model for a distributed real-time water information system assists the interpretation of the data product and establishing trust. Reference [1] Taylor, P., Walker, G., Valentine, D., Cox, Simon: WaterML2.0: Harmonising standards for water observation data. Geophysical Research Abstracts. Vol. 12. [2] da Silva, P.P., McGuinness, D.L., Fikes, R.: A proof markup language for semantic web services. Inf. Syst. 31(4) (2006), 381-395. [3] W3C Semantic Sensor Network Incubator Group http://www.w3.org/2005/Incubator

  18. Characteristics and control response of the TOPAZ II Reactor System Real-time Dynamic Simulator

    SciTech Connect

    Kwok, K.S.

    1993-11-12

    A dynamic simulator of the TOPAZ II reactor system has been developed for the Nuclear Electric Propulsion Space Test Program. The simulator combines first-principle modeling and empirical correlations in its algorithm to attain the modeling accuracy and computational through-put that are required for real-time execution. The overall execution time of the simulator for each time step is 15 ms when no data is written to the disk, and 18 ms when nine double precision data points are written to the disk once in every time step. The simulation program has been tested and it is able to handle a step decrease of $8 worth of reactivity. It also provides simulations of fuel, emitter, collector, stainless steel, and ZrH moderator failures. Presented in this paper are the models used in the calculations, a sample simulation session, and a discussion of the performance and limitations of the simulator. The simulator has been found to provide realistic real-time dynamic response of the TOPAZ II reactor system under both normal and casualty conditions.

  19. Real-Time linux dynamic clamp: a fast and flexible way to construct virtual ion channels in living cells.

    PubMed

    Dorval, A D; Christini, D J; White, J A

    2001-10-01

    We describe a system for real-time control of biological and other experiments. This device, based around the Real-Time Linux operating system, was tested specifically in the context of dynamic clamping, a demanding real-time task in which a computational system mimics the effects of nonlinear membrane conductances in living cells. The system is fast enough to represent dozens of nonlinear conductances in real time at clock rates well above 10 kHz. Conductances can be represented in deterministic form, or more accurately as discrete collections of stochastically gating ion channels. Tests were performed using a variety of complex models of nonlinear membrane mechanisms in excitable cells, including simulations of spatially extended excitable structures, and multiple interacting cells. Only in extreme cases does the computational load interfere with high-speed "hard" real-time processing (i.e., real-time processing that never falters). Freely available on the worldwide web, this experimental control system combines good performance. immense flexibility, low cost, and reasonable ease of use. It is easily adapted to any task involving real-time control, and excels in particular for applications requiring complex control algorithms that must operate at speeds over 1 kHz.

  20. Holographic entropy and real-time dynamics of quarkonium dissociation in non-Abelian plasma

    DOE PAGES

    Iatrakis, Ioannis; Kharzeev, Dmitri E.

    2016-04-26

    The peak of the heavy quark pair entropy at the deconfinement transition, observed in lattice QCD, suggests that the transition is effectively driven by the increase of the entropy of bound states. The growth of the entropy with the interquark distance leads to the emergent entropic force that induces dissociation of quarkonium states. Since the quark-gluon plasma around the transition point is a strongly coupled system, we use the gauge-gravity duality to study the entropy of heavy quarkonium and the real-time dynamics of its dissociation. In particular, we employ the improved holographic QCD model as a dual description of largemore » Nc Yang-Mills theory. Studying the dynamics of the fundamental string between the quarks placed on the boundary, we find that the entropy peaks at the transition point. We also study the real-time dynamics of the system by considering the holographic string falling in the black hole horizon where it equilibrates. As a result, in the vicinity of the deconfinement transition, the dissociation time is found to be less than a fermi, suggesting that the entropic destruction is the dominant dissociation mechanism in this temperature region.« less

  1. Holographic entropy and real-time dynamics of quarkonium dissociation in non-Abelian plasma

    SciTech Connect

    Iatrakis, Ioannis; Kharzeev, Dmitri E.

    2016-04-26

    The peak of the heavy quark pair entropy at the deconfinement transition, observed in lattice QCD, suggests that the transition is effectively driven by the increase of the entropy of bound states. The growth of the entropy with the interquark distance leads to the emergent entropic force that induces dissociation of quarkonium states. Since the quark-gluon plasma around the transition point is a strongly coupled system, we use the gauge-gravity duality to study the entropy of heavy quarkonium and the real-time dynamics of its dissociation. In particular, we employ the improved holographic QCD model as a dual description of large Nc Yang-Mills theory. Studying the dynamics of the fundamental string between the quarks placed on the boundary, we find that the entropy peaks at the transition point. We also study the real-time dynamics of the system by considering the holographic string falling in the black hole horizon where it equilibrates. As a result, in the vicinity of the deconfinement transition, the dissociation time is found to be less than a fermi, suggesting that the entropic destruction is the dominant dissociation mechanism in this temperature region.

  2. A Macroscopic Mathematical Model for Cell Migration Assays Using a Real-Time Cell Analysis

    PubMed Central

    Angelini, Claudia; Carfora, Maria Francesca; Carriero, Maria Vincenza; Natalini, Roberto

    2016-01-01

    Experiments of cell migration and chemotaxis assays have been classically performed in the so-called Boyden Chambers. A recent technology, xCELLigence Real Time Cell Analysis, is now allowing to monitor the cell migration in real time. This technology measures impedance changes caused by the gradual increase of electrode surface occupation by cells during the course of time and provide a Cell Index which is proportional to cellular morphology, spreading, ruffling and adhesion quality as well as cell number. In this paper we propose a macroscopic mathematical model, based on advection-reaction-diffusion partial differential equations, describing the cell migration assay using the real-time technology. We carried out numerical simulations to compare simulated model dynamics with data of observed biological experiments on three different cell lines and in two experimental settings: absence of chemotactic signals (basal migration) and presence of a chemoattractant. Overall we conclude that our minimal mathematical model is able to describe the phenomenon in the real time scale and numerical results show a good agreement with the experimental evidences. PMID:27680883

  3. A Macroscopic Mathematical Model for Cell Migration Assays Using a Real-Time Cell Analysis.

    PubMed

    Di Costanzo, Ezio; Ingangi, Vincenzo; Angelini, Claudia; Carfora, Maria Francesca; Carriero, Maria Vincenza; Natalini, Roberto

    Experiments of cell migration and chemotaxis assays have been classically performed in the so-called Boyden Chambers. A recent technology, xCELLigence Real Time Cell Analysis, is now allowing to monitor the cell migration in real time. This technology measures impedance changes caused by the gradual increase of electrode surface occupation by cells during the course of time and provide a Cell Index which is proportional to cellular morphology, spreading, ruffling and adhesion quality as well as cell number. In this paper we propose a macroscopic mathematical model, based on advection-reaction-diffusion partial differential equations, describing the cell migration assay using the real-time technology. We carried out numerical simulations to compare simulated model dynamics with data of observed biological experiments on three different cell lines and in two experimental settings: absence of chemotactic signals (basal migration) and presence of a chemoattractant. Overall we conclude that our minimal mathematical model is able to describe the phenomenon in the real time scale and numerical results show a good agreement with the experimental evidences.

  4. Determinants of the spatiotemporal dynamics of the 2009 H1N1 pandemic in Europe: implications for real-time modelling.

    PubMed

    Merler, Stefano; Ajelli, Marco; Pugliese, Andrea; Ferguson, Neil M

    2011-09-01

    Influenza pandemics in the last century were characterized by successive waves and differences in impact and timing between different regions, for reasons not clearly understood. The 2009 H1N1 pandemic showed rapid global spread, but with substantial heterogeneity in timing within each hemisphere. Even within Europe substantial variation was observed, with the UK being unique in experiencing a major first wave of transmission in early summer and all other countries having a single major epidemic in the autumn/winter, with a West to East pattern of spread. Here we show that a microsimulation model, parameterised using data about H1N1pdm collected by the beginning of June 2009, explains the occurrence of two waves in UK and a single wave in the rest of Europe as a consequence of timing of H1N1pdm spread, fluxes of travels from US and Mexico, and timing of school vacations. The model provides a description of pandemic spread through Europe, depending on intra-European mobility patterns and socio-demographic structure of the European populations, which is in broad agreement with observed timing of the pandemic in different countries. Attack rates are predicted to depend on the socio-demographic structure, with age dependent attack rates broadly agreeing with available serological data. Results suggest that the observed heterogeneity can be partly explained by the between country differences in Europe: marked differences in school calendars, mobility patterns and sociodemographic structures. Moreover, higher susceptibility of children to infection played a key role in determining the epidemiology of the 2009 pandemic. Our work shows that it would have been possible to obtain a broad-brush prediction of timing of the European pandemic well before the autumn of 2009, much more difficult to achieve with simpler models or pre-pandemic parameterisation. This supports the use of models accounting for the structure of complex modern societies for giving insight to policy

  5. Determinants of the Spatiotemporal Dynamics of the 2009 H1N1 Pandemic in Europe: Implications for Real-Time Modelling

    PubMed Central

    Merler, Stefano; Ajelli, Marco; Pugliese, Andrea; Ferguson, Neil M.

    2011-01-01

    Influenza pandemics in the last century were characterized by successive waves and differences in impact and timing between different regions, for reasons not clearly understood. The 2009 H1N1 pandemic showed rapid global spread, but with substantial heterogeneity in timing within each hemisphere. Even within Europe substantial variation was observed, with the UK being unique in experiencing a major first wave of transmission in early summer and all other countries having a single major epidemic in the autumn/winter, with a West to East pattern of spread. Here we show that a microsimulation model, parameterised using data about H1N1pdm collected by the beginning of June 2009, explains the occurrence of two waves in UK and a single wave in the rest of Europe as a consequence of timing of H1N1pdm spread, fluxes of travels from US and Mexico, and timing of school vacations. The model provides a description of pandemic spread through Europe, depending on intra-European mobility patterns and socio-demographic structure of the European populations, which is in broad agreement with observed timing of the pandemic in different countries. Attack rates are predicted to depend on the socio-demographic structure, with age dependent attack rates broadly agreeing with available serological data. Results suggest that the observed heterogeneity can be partly explained by the between country differences in Europe: marked differences in school calendars, mobility patterns and sociodemographic structures. Moreover, higher susceptibility of children to infection played a key role in determining the epidemiology of the 2009 pandemic. Our work shows that it would have been possible to obtain a broad-brush prediction of timing of the European pandemic well before the autumn of 2009, much more difficult to achieve with simpler models or pre-pandemic parameterisation. This supports the use of models accounting for the structure of complex modern societies for giving insight to policy

  6. Modeling and real-time control of urban drainage systems: A review

    NASA Astrophysics Data System (ADS)

    García, L.; Barreiro-Gomez, J.; Escobar, E.; Téllez, D.; Quijano, N.; Ocampo-Martinez, C.

    2015-11-01

    Urban drainage systems (UDS) may be considered large-scale systems given their large number of associated states and decision actions, making challenging their real-time control (RTC) design. Moreover, the complexity of the dynamics of the UDS makes necessary the development of strategies for the control design. This paper reviews and discusses several techniques and strategies commonly used for the control of UDS. Moreover, the models to describe, simulate, and control the transport of wastewater in UDS are also reviewed.

  7. Real-time micro-modelling of city evacuations

    NASA Astrophysics Data System (ADS)

    Löhner, Rainald; Haug, Eberhard; Zinggerling, Claudio; Oñate, Eugenio

    2017-01-01

    A methodology to integrate geographical information system (GIS) data with large-scale pedestrian simulations has been developed. Advances in automatic data acquisition and archiving from GIS databases, automatic input for pedestrian simulations, as well as scalable pedestrian simulation tools have made it possible to simulate pedestrians at the individual level for complete cities in real time. An example that simulates the evacuation of the city of Barcelona demonstrates that this is now possible. This is the first step towards a fully integrated crowd prediction and management tool that takes into account not only data gathered in real time from cameras, cell phones or other sensors, but also merges these with advanced simulation tools to predict the future state of the crowd.

  8. A Real-Time Air Dispersion Modeling System.

    DTIC Science & Technology

    1984-04-01

    Toxic Corridors Spills of Toxic Chemicals 20. ABSTRACT (Continue on reveres side If necessary and Identify by block numbe,) .This report documents a...microcomputer-based system for the real-time computation of toxic corridors associated with chemical releases. The program assists the user with...interactive input of critical meteorological parameters and accesses user-specified data bases of information regarding toxic chemical attributes. Graphic

  9. An Innovative Real-time Environment for Unified Deterministic and Stochastic Groundwater Modeling

    NASA Astrophysics Data System (ADS)

    Li, S.; Liu, Q.

    2003-12-01

    , and mass balance analyses. IGW continually provides and displays results that are intelligently processed, organized, overlaid, and displayed. It seamlessly and dynamically merges heterogeneous geo-spatial data into graphical images - integrating related data to reveal the complex interplay among the geology, hydrology and chemistry across multiple spatial and time scales. This unprecedented capability in real-time modeling, steering, integration, analysis, and visualization transforms the way we model and profoundly expands the utility of groundwater model as a tool for research, education, and professional investigation related to groundwater.

  10. Optical Response of Warm Dense Matter Using Real-Time Electron Dynamics

    NASA Astrophysics Data System (ADS)

    Baczewski, Andrew; Shulenburger, Luke; Desjarlais, Michael; Magyar, Rudolph

    2014-03-01

    The extreme temperatures and solid-like densities in warm dense matter present a unique challenge for theory, wherein neither conventional models from condensed matter nor plasma physics capture all of the relevant phenomenology. While Kubo-Greenwood DFT calculations have proven capable of reproducing optical properties of WDM, they require a significant number of virtual orbitals to reach convergence due to their perturbative nature. Real-time TDDFT presents a complementary framework with a number of computationally favorable properties, including reduced cost complexity and better scalability, and has been used to reproduce the optical response of finite and ordered extended systems. We will describe the use of Ehrenfest-TDDFT to evolve coupled electron-nuclear dynamics in WDM systems, and the subsequent evaluation of optical response functions from the real-time electron dynamics. The advantages and disadvantages of this approach will be discussed relative to the current state-of-the-art. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Security Administration under contract DE-AC04-94AL85000.

  11. Crowd dynamics evacuations: The roles of shape optimization and real-time computational models. Comment on "Human behaviours in evacuation crowd dynamics: From modelling to "big data" toward crisis management" by Nicola Bellomo et al.

    NASA Astrophysics Data System (ADS)

    Delle Monache, Maria Laura

    2016-09-01

    This paper focuses on mathematical models for crowd dynamics in real life situations for support to decision making in critical situations. It deals with the modeling and the computations in the light of improving safety and pedestrians behavior.

  12. Ultrasound-array-based real-time photoacoustic microscopy of human pulsatile dynamics in vivo

    NASA Astrophysics Data System (ADS)

    Song, Liang; Maslov, Konstantin; Shung, K. Kirk; Wang, Lihong V.

    2010-03-01

    With a refined ultrasound-array-based real-time photoacoustic microscopy (UA-PAM) system, we demonstrate the feasibility of noninvasive in vivo imaging of human pulsatile dynamics. The system, capable of real-time B-scan imaging at 50 Hz and high-speed 3-D imaging, is validated by imaging the subcutaneous microvasculature in rats and humans. After the validation, a human artery around the palm-wrist area is imaged, and its pulsatile dynamics, including the arterial pulsatile motion and changes in hemoglobin concentration, is monitored with 20-ms B-scan imaging temporal resolution. To our knowledge, this is the first demonstration of real-time photoacoustic imaging of human physiological dynamics. Our results show that UA-PAM can potentially enable many new possibilities for studying functional and physiological dynamics in both preclinical and clinical imaging settings.

  13. Validating the Rice neural network and the Wing Kp real-time models

    NASA Astrophysics Data System (ADS)

    Bala, Ramkumar; Reiff, Patricia

    2014-06-01

    The Rice neural network models of Kp have been running in real time at http://mms.rice.edu/realtime/forecast.html since October 2007; Dst and AE models were added to our operations in May 2010. All these models use the Boyle index as basis functions computed from ACE real time inputs. Later, two more driving functions were included in November 2012: (a) the "Ram" functions that had dynamic pressure term added to the Boyle index and (b) the Newell functions. The Wing models are a set of neural network-based Kp forecast models adopted by NOAA/Space Weather Prediction Center in March 2011 to supersede the Costello Kp model. This study indicates that any of the three Rice neural net predictors had a better success rate than the Wing model in predicting Kp (r=0.828 with Boyle, r=0.843 with Ram, and r=0.820 with Newell for 1 h predictions; similarly, r=0.739, 0.769, and 0.755 for 3 h predictions) in real time. In a head-to-head challenge using harvested real-time outputs between April 2011 and February 2013, the Rice Boyle Kp models predicted better than the Wing models (0.771 versus 0.714 for 1 h predictions and 0.770 versus 0.744 for 3 h predictions). In addition, Wing's prediction was missing more often than the Rice prediction (≈6% versus 4.6%), meaning it had less reliability. The Rice models also predict AE(r=0.811 with Boyle; 0.806 with Ram; 0.765 with Newell, and 0.743 with Boyle; 0.747 with Ram for 1 h and 3 h predictions) and pressure-corrected Dst (r=0.790; 0.767, and 0.704, and r=0.795; 0.797 and 0.707 for 1 h and 3 h predictions).

  14. A generalised Dynamic Overflow Risk Assessment (DORA) for Real Time Control of urban drainage systems

    NASA Astrophysics Data System (ADS)

    Vezzaro, Luca; Grum, Morten

    2014-07-01

    An innovative and generalised approach to the integrated Real Time Control of urban drainage systems is presented. The Dynamic Overflow Risk Assessment (DORA) strategy aims to minimise the expected Combined Sewer Overflow (CSO) risk by considering (i) the water volume presently stored in the drainage network, (ii) the expected runoff volume (calculated by radar-based nowcast models) and - most important - (iii) the estimated uncertainty of the runoff forecasts. The inclusion of uncertainty allows for a more confident use of Real Time Control (RTC). Overflow risk is calculated by a flexible function which allows for the prioritisation of the discharge points according to their sensitivity and intended use. DORA was tested on a hypothetical example inspired by the main catchment in the city of Aarhus (Denmark). An analysis of DORA’s performance over a range of events with different return periods, using a simple conceptual model, is presented. Compared to a traditional local control approach, DORA contributed to reduce CSO volumes from the most sensitive points while reducing total CSO volumes discharged from the catchment. Additionally, the results show that the inclusion of forecasts and their uncertainty contributed to further improving the performance of drainage systems. The results of this paper will contribute to the wider usage of global RTC methods in the management of urban drainage networks.

  15. REAL-TIME MODEL-BASED ELECTRICAL POWERED WHEELCHAIR CONTROL

    PubMed Central

    Wang, Hongwu; Salatin, Benjamin; Grindle, Garrett G.; Ding, Dan; Cooper, Rory A.

    2009-01-01

    The purpose of this study was to evaluate the effects of three different control methods on driving speed variation and wheel-slip of an electric-powered wheelchair (EPW). A kinematic model as well as 3-D dynamic model was developed to control the velocity and traction of the wheelchair. A smart wheelchair platform was designed and built with a computerized controller and encoders to record wheel speeds and to detect the slip. A model based, a proportional-integral-derivative (PID) and an open-loop controller were applied with the EPW driving on four different surfaces at three specified speeds. The speed errors, variation, rise time, settling time and slip coefficient were calculated and compared for a speed step-response input. Experimental results showed that model based control performed best on all surfaces across the speeds. PMID:19733494

  16. Real-time model based electrical powered wheelchair control.

    PubMed

    Wang, Hongwu; Salatin, Benjamin; Grindle, Garrett G; Ding, Dan; Cooper, Rory A

    2009-12-01

    The purpose of this study was to evaluate the effects of three different control methods on driving speed variation and wheel slip of an electric-powered wheelchair (EPW). A kinematic model as well as 3D dynamic model was developed to control the velocity and traction of the wheelchair. A smart wheelchair platform was designed and built with a computerized controller and encoders to record wheel speeds and to detect the slip. A model based, a proportional-integral-derivative (PID) and an open-loop controller were applied with the EPW driving on four different surfaces at three specified speeds. The speed errors, variation, rise time, settling time and slip coefficient were calculated and compared for a speed step-response input. Experimental results showed that model based control performed best on all surfaces across the speeds.

  17. Real-time probabilistic covariance tracking with efficient model update.

    PubMed

    Wu, Yi; Cheng, Jian; Wang, Jinqiao; Lu, Hanqing; Wang, Jun; Ling, Haibin; Blasch, Erik; Bai, Li

    2012-05-01

    The recently proposed covariance region descriptor has been proven robust and versatile for a modest computational cost. The covariance matrix enables efficient fusion of different types of features, where the spatial and statistical properties, as well as their correlation, are characterized. The similarity between two covariance descriptors is measured on Riemannian manifolds. Based on the same metric but with a probabilistic framework, we propose a novel tracking approach on Riemannian manifolds with a novel incremental covariance tensor learning (ICTL). To address the appearance variations, ICTL incrementally learns a low-dimensional covariance tensor representation and efficiently adapts online to appearance changes of the target with only O(1) computational complexity, resulting in a real-time performance. The covariance-based representation and the ICTL are then combined with the particle filter framework to allow better handling of background clutter, as well as the temporary occlusions. We test the proposed probabilistic ICTL tracker on numerous benchmark sequences involving different types of challenges including occlusions and variations in illumination, scale, and pose. The proposed approach demonstrates excellent real-time performance, both qualitatively and quantitatively, in comparison with several previously proposed trackers.

  18. Dynamic Adjustment of Stimuli in Real Time Functional Magnetic Resonance Imaging

    PubMed Central

    Feng, I. Jung; Jack, Anthony I.; Tatsuoka, Curtis

    2015-01-01

    The conventional fMRI image analysis approach to associating stimuli to brain activation is performed by carrying out a massive number of parallel univariate regression analyses. fMRI blood-oxygen-level dependent (BOLD) signal, the basis of these analyses, is known for its low signal-noise-ratio and high spatial and temporal signal correlation. In order to ensure accurate localization of brain activity, stimulus administration in an fMRI session is often lengthy and repetitive. Real-time fMRI BOLD signal analysis is carried out as the signal is observed. This method allows for dynamic, real-time adjustment of stimuli through sequential experimental designs. We have developed a voxel-wise sequential probability ratio test (SPRT) approach for dynamically determining localization, as well as decision rules for stopping stimulus administration. SPRT methods and general linear model (GLM) approaches are combined to identify brain regions that are activated by specific elements of stimuli. Stimulus administration is dynamically stopped when sufficient statistical evidence is collected to determine activation status across regions of interest, following predetermined statistical error thresholds. Simulation experiments and an example based on real fMRI data show that scan volumes can be substantially reduced when compared with pre-determined, fixed designs while achieving similar or better accuracy in detecting activated voxels. Moreover, the proposed approach is also able to accurately detect differentially activated areas, and other comparisons between task-related GLM parameters that can be formulated in a hypothesis-testing framework. Finally, we give a demonstration of SPRT being employed in conjunction with a halving algorithm to dynamically adjust stimuli. PMID:25785856

  19. Generic Spacecraft Model for Real-Time Simulation

    NASA Technical Reports Server (NTRS)

    Kenney, Patrick S.; Ragsdale, William; Neuhaus, Jason R.

    2008-01-01

    Generic Spacecraft is the name of an evolving library of software that provides for simulation of a generic spacecraft that can orbit the Earth and land on the Moon (and, eventually, on Mars). This library is incorporated into the Langley Standard Realtime Simulation in C++ (LaSRS++) software framework. The generic-spacecraft simulation serves as a test bed for modeling spacecraft dynamics, propulsion, control systems, guidance, and displays. The Generic Spacecraft library supplements the LaSRS++ framework with an interface that facilitates the connection of new models into the LaSRS++ simulation by eliminating what would otherwise be the necessity of writing additional C++ classes to record data from the models and code to display values on graphical user interfaces (GUIs): The library includes routines for integrating new models into the LaSRS++ framework, identifying model inputs and outputs with full descriptions and units identified, recording data, and automatically generating graphical user interfaces (GUIs). The library is designed to be used in a manner similar to that of LaSRS++ software components for simulating vehicles other than the generic spacecraft. The user specifies (1) a spacecraft and individual models to be constructed and (2) connections between individual model inputs and outputs.

  20. A Study on Modeling of Transmission Line in Digital Type Real-Time Power System Simulator

    NASA Astrophysics Data System (ADS)

    Yasuda, Yuji; Yokoyama, Akihiko; Tada, Yasuyuki

    In modern power systems, it is important to analyze various kindes of dynamic phenomena which appear in the system. When the effectiveness of new power electronics based apparatus, protective relay systems and etc. is tested, a real-time power system simulator is becoming a very effective tool. In general, however, it is very expensive and it is very difficult for beginners to understand how to use it. Therefore, studies on low-cost and easy-use real-time power system simulators have so far been done. We have developed models of power system components for the real-time power system simulator using DSP (Digital Signal Processor) combined with commercial CAD (Computer Aided Design) soft "MATLAB/SIMULINK". The use of commercial softwares can drastically decrease the development cost of the simulator. In this paper, a simplified reduction model of unbalanced three-phase transmission network with mutual impedance is proposed for analysis of various kinds of stability phenomena by use of the digital simulator. The proposed network model is constructed automatically and efficiently even for connection of both current source type models and voltage source type models of power apparatus such as generators, FACTS devices and loads.

  1. Real-time Visualization of Tissue Dynamics during Embryonic Development and Malignant Transformation

    NASA Astrophysics Data System (ADS)

    Yamada, Kenneth

    Tissues undergo dramatic changes in organization during embryonic development, as well as during cancer progression and invasion. Recent advances in microscopy now allow us to visualize and track directly the dynamic movements of tissues, their constituent cells, and cellular substructures. This behavior can now be visualized not only in regular tissue culture on flat surfaces (`2D' environments), but also in a variety of 3D environments that may provide physiological cues relevant to understanding dynamics within living organisms. Acquisition of imaging data using various microscopy modalities will provide rich opportunities for determining the roles of physical factors and for computational modeling of complex processes in living tissues. Direct visualization of real-time motility is providing insight into biology spanning multiple spatio-temporal scales. Many cells in our body are known to be in contact with connective tissue and other forms of extracellular matrix. They do so through microscopic cellular adhesions that bind to matrix proteins. In particular, fluorescence microscopy has revealed that cells dynamically probe and bend the matrix at the sites of cell adhesions, and that 3D matrix architecture, stiffness, and elasticity can each regulate migration of the cells. Conversely, cells remodel their local matrix as organs form or tumors invade. Cancer cells can invade tissues using microscopic protrusions that degrade the surrounding matrix; in this case, the local matrix protein concentration is more important for inducing the micro-invasive protrusions than stiffness. On the length scales of tissues, transiently high rates of individual cell movement appear to help establish organ architecture. In fact, isolated cells can self-organize to form tissue structures. In all of these cases, in-depth real-time visualization will ultimately provide the extensive data needed for computer modeling and for testing hypotheses in which physical forces interact

  2. Can the ring polymer molecular dynamics method be interpreted as real time quantum dynamics?

    SciTech Connect

    Jang, Seogjoo; Sinitskiy, Anton V.; Voth, Gregory A.

    2014-04-21

    The ring polymer molecular dynamics (RPMD) method has gained popularity in recent years as a simple approximation for calculating real time quantum correlation functions in condensed media. However, the extent to which RPMD captures real dynamical quantum effects and why it fails under certain situations have not been clearly understood. Addressing this issue has been difficult in the absence of a genuine justification for the RPMD algorithm starting from the quantum Liouville equation. To this end, a new and exact path integral formalism for the calculation of real time quantum correlation functions is presented in this work, which can serve as a rigorous foundation for the analysis of the RPMD method as well as providing an alternative derivation of the well established centroid molecular dynamics method. The new formalism utilizes the cyclic symmetry of the imaginary time path integral in the most general sense and enables the expression of Kubo-transformed quantum time correlation functions as that of physical observables pre-averaged over the imaginary time path. Upon filtering with a centroid constraint function, the formulation results in the centroid dynamics formalism. Upon filtering with the position representation of the imaginary time path integral, we obtain an exact quantum dynamics formalism involving the same variables as the RPMD method. The analysis of the RPMD approximation based on this approach clarifies that an explicit quantum dynamical justification does not exist for the use of the ring polymer harmonic potential term (imaginary time kinetic energy) as implemented in the RPMD method. It is analyzed why this can cause substantial errors in nonlinear correlation functions of harmonic oscillators. Such errors can be significant for general correlation functions of anharmonic systems. We also demonstrate that the short time accuracy of the exact path integral limit of RPMD is of lower order than those for finite discretization of path. The

  3. A Comprehensive Software System for Interactive, Real-time, Visual 3D Deterministic and Stochastic Groundwater Modeling

    NASA Astrophysics Data System (ADS)

    Li, S.

    2002-05-01

    Taking advantage of the recent developments in groundwater modeling research and computer, image and graphics processing, and objected oriented programming technologies, Dr. Li and his research group have recently developed a comprehensive software system for unified deterministic and stochastic groundwater modeling. Characterized by a new real-time modeling paradigm and improved computational algorithms, the software simulates 3D unsteady flow and reactive transport in general groundwater formations subject to both systematic and "randomly" varying stresses and geological and chemical heterogeneity. The software system has following distinct features and capabilities: Interactive simulation and real time visualization and animation of flow in response to deterministic as well as stochastic stresses. Interactive, visual, and real time particle tracking, random walk, and reactive plume modeling in both systematically and randomly fluctuating flow. Interactive statistical inference, scattered data interpolation, regression, and ordinary and universal Kriging, conditional and unconditional simulation. Real-time, visual and parallel conditional flow and transport simulations. Interactive water and contaminant mass balance analysis and visual and real-time flux update. Interactive, visual, and real time monitoring of head and flux hydrographs and concentration breakthroughs. Real-time modeling and visualization of aquifer transition from confined to unconfined to partially de-saturated or completely dry and rewetting Simultaneous and embedded subscale models, automatic and real-time regional to local data extraction; Multiple subscale flow and transport models Real-time modeling of steady and transient vertical flow patterns on multiple arbitrarily-shaped cross-sections and simultaneous visualization of aquifer stratigraphy, properties, hydrological features (rivers, lakes, wetlands, wells, drains, surface seeps), and dynamically adjusted surface flooding area

  4. Resolving dynamics of cell signaling via real-time imaging of the immunological synapse.

    SciTech Connect

    Stevens, Mark A.; Pfeiffer, Janet R.; Wilson, Bridget S.; Timlin, Jerilyn Ann; Thomas, James L.; Lidke, Keith A.; Spendier, Kathrin; Oliver, Janet M.; Carroll-Portillo, Amanda; Aaron, Jesse S.; Mirijanian, Dina T.; Carson, Bryan D.; Burns, Alan Richard; Rebeil, Roberto

    2009-10-01

    This highly interdisciplinary team has developed dual-color, total internal reflection microscopy (TIRF-M) methods that enable us to optically detect and track in real time protein migration and clustering at membrane interfaces. By coupling TIRF-M with advanced analysis techniques (image correlation spectroscopy, single particle tracking) we have captured subtle changes in membrane organization that characterize immune responses. We have used this approach to elucidate the initial stages of cell activation in the IgE signaling network of mast cells and the Toll-like receptor (TLR-4) response in macrophages stimulated by bacteria. To help interpret these measurements, we have undertaken a computational modeling effort to connect the protein motion and lipid interactions. This work provides a deeper understanding of the initial stages of cellular response to external agents, including dynamics of interaction of key components in the signaling network at the 'immunological synapse,' the contact region of the cell and its adversary.

  5. Traffic dynamics: Method for estimating freeway travel times in real time from flow measurements

    SciTech Connect

    Nam, D.H.; Drew, D.R.

    1996-05-01

    This paper presents a method for estimating freeway travel times in real time directly from flow measurements, which is desirable for present and future Intelligent Vehicle-Highway Systems (IVHS) applications. An inductive modeling approach adapted here is based on stochastic queuing theory and the principle of conservation of vehicles. The analytical expression for link travel times satisfies traffic dynamics where the new form of the conservation of vehicles has been derived under generalized traffic conditions. A computer program has been developed to implement the algorithm. Analysis results show that the estimates have good agreement with empirical data measured at 30-s intervals. This methodology has potential applicable to automatic traffic control and automatic incident detection.

  6. Integration of domain and resource-based reasoning for real-time control in dynamic environments

    NASA Technical Reports Server (NTRS)

    Morgan, Keith; Whitebread, Kenneth R.; Kendus, Michael; Cromarty, Andrew S.

    1993-01-01

    A real-time software controller that successfully integrates domain-based and resource-based control reasoning to perform task execution in a dynamically changing environment is described. The design of the controller is based on the concept of partitioning the process to be controlled into a set of tasks, each of which achieves some process goal. It is assumed that, in general, there are multiple ways (tasks) to achieve a goal. The controller dynamically determines current goals and their current criticality, choosing and scheduling tasks to achieve those goals in the time available. It incorporates rule-based goal reasoning, a TMS-based criticality propagation mechanism, and a real-time scheduler. The controller has been used to build a knowledge-based situation assessment system that formed a major component of a real-time, distributed, cooperative problem solving system built under DARPA contract. It is also being employed in other applications now in progress.

  7. Model-based planning and real-time predictive control for laser-induced thermal therapy

    PubMed Central

    Feng, Yusheng; Fuentes, David

    2014-01-01

    In this article, the major idea and mathematical aspects of model-based planning and real-time predictive control for laser-induced thermal therapy (LITT) are presented. In particular, a computational framework and its major components developed by authors in recent years are reviewed. The framework provides the backbone for not only treatment planning but also real-time surgical monitoring and control with a focus on MR thermometry enabled predictive control and applications to image-guided LITT, or MRgLITT. Although this computational framework is designed for LITT in treating prostate cancer, it is further applicable to other thermal therapies in focal lesions induced by radio-frequency (RF), microwave and high-intensity-focused ultrasound (HIFU). Moreover, the model-based dynamic closed-loop predictive control algorithms in the framework, facilitated by the coupling of mathematical modelling and computer simulation with real-time imaging feedback, has great potential to enable a novel methodology in thermal medicine. Such technology could dramatically increase treatment efficacy and reduce morbidity. PMID:22098360

  8. Real-time physics-based 3D biped character animation using an inverted pendulum model.

    PubMed

    Tsai, Yao-Yang; Lin, Wen-Chieh; Cheng, Kuangyou B; Lee, Jehee; Lee, Tong-Yee

    2010-01-01

    We present a physics-based approach to generate 3D biped character animation that can react to dynamical environments in real time. Our approach utilizes an inverted pendulum model to online adjust the desired motion trajectory from the input motion capture data. This online adjustment produces a physically plausible motion trajectory adapted to dynamic environments, which is then used as the desired motion for the motion controllers to track in dynamics simulation. Rather than using Proportional-Derivative controllers whose parameters usually cannot be easily set, our motion tracking adopts a velocity-driven method which computes joint torques based on the desired joint angular velocities. Physically correct full-body motion of the 3D character is computed in dynamics simulation using the computed torques and dynamical model of the character. Our experiments demonstrate that tracking motion capture data with real-time response animation can be achieved easily. In addition, physically plausible motion style editing, automatic motion transition, and motion adaptation to different limb sizes can also be generated without difficulty.

  9. Dynamic Beam Solutions for Real-Time Simulation and Control Development of Flexible Rockets

    NASA Technical Reports Server (NTRS)

    Su, Weihua; King, Cecilia K.; Clark, Scott R.; Griffin, Edwin D.; Suhey, Jeffrey D.; Wolf, Michael G.

    2016-01-01

    In this study, flexible rockets are structurally represented by linear beams. Both direct and indirect solutions of beam dynamic equations are sought to facilitate real-time simulation and control development for flexible rockets. The direct solution is completed by numerically integrate the beam structural dynamic equation using an explicit Newmark-based scheme, which allows for stable and fast transient solutions to the dynamics of flexile rockets. Furthermore, in the real-time operation, the bending strain of the beam is measured by fiber optical sensors (FOS) at intermittent locations along the span, while both angular velocity and translational acceleration are measured at a single point by the inertial measurement unit (IMU). Another study in this paper is to find the analytical and numerical solutions of the beam dynamics based on the limited measurement data to facilitate the real-time control development. Numerical studies demonstrate the accuracy of these real-time solutions to the beam dynamics. Such analytical and numerical solutions, when integrated with data processing and control algorithms and mechanisms, have the potential to increase launch availability by processing flight data into the flexible launch vehicle's control system.

  10. Applying MDA to SDR for Space to Model Real-time Issues

    NASA Technical Reports Server (NTRS)

    Blaser, Tammy M.

    2007-01-01

    NASA space communications systems have the challenge of designing SDRs with highly-constrained Size, Weight and Power (SWaP) resources. A study is being conducted to assess the effectiveness of applying the MDA Platform-Independent Model (PIM) and one or more Platform-Specific Models (PSM) specifically to address NASA space domain real-time issues. This paper will summarize our experiences with applying MDA to SDR for Space to model real-time issues. Real-time issues to be examined, measured, and analyzed are: meeting waveform timing requirements and efficiently applying Real-time Operating System (RTOS) scheduling algorithms, applying safety control measures, and SWaP verification. Real-time waveform algorithms benchmarked with the worst case environment conditions under the heaviest workload will drive the SDR for Space real-time PSM design.

  11. Real-time estimation of TP load in a Mississippi Delta stream using a dynamic data driven application system.

    PubMed

    Ouyang, Ying; Leininger, Theodor D; Hatten, Jeff

    2013-06-15

    Elevated phosphorus (P) in surface waters can cause eutrophication of aquatic ecosystems and can impair water for drinking, industry, agriculture, and recreation. Currently, no effort has been devoted to estimating real-time variation and load of total P (TP) in surface waters due to the lack of suitable and/or cost-effective wireless sensors. However, when considering human health, drinking water supply, and rapidly developing events such as algal blooms, the availability of timely P information is very critical. In this study, we developed a new approach in the form of a dynamic data driven application system (DDDAS) for monitoring the real-time variation and load of TP in surface water. This DDDAS consisted of the following three major components: (1) a User Control that interacts with Schedule Run to implement the DDDAS with starting and ending times; (2) a Schedule Run that activates the Hydstra model; and (3) a Hydstra model that downloads the real-time data from a US Geological Survey (USGS) website that is updated every 15 min with data from USGS monitoring stations, predicts real-time variation and load of TP, graphs the variables in real-time on a computer screen, and sends email alerts when the TP exceeds a certain value. The DDDAS was applied to monitor real-time variation and load of TP for 30 days in Deer Creek, a stream located east of Leland, Mississippi, USA. Results showed that the TP concentrations in the stream ranged from 0.24 to 0.48 mg L(-1) with an average of 0.30 mg L(-1) for a 30-day monitoring period, whereas the cumulative load of TP from the stream was about 2.8 kg for the same monitoring period. Our study suggests that the DDDAS developed in this study was useful for estimating the real-time variation and load of TP in surface water ecosystems.

  12. Real-time submillisecond single-molecule FRET dynamics of freely diffusing molecules with liposome tethering

    NASA Astrophysics Data System (ADS)

    Kim, Jae-Yeol; Kim, Cheolhee; Lee, Nam Ki

    2015-04-01

    Single-molecule fluorescence resonance energy transfer (smFRET) is one of the powerful techniques for deciphering the dynamics of unsynchronized biomolecules. However, smFRET is limited in its temporal resolution for observing dynamics. Here, we report a novel method for observing real-time dynamics with submillisecond resolution by tethering molecules to freely diffusing 100-nm-sized liposomes. The observation time for a diffusing molecule is extended to 100 ms with a submillisecond resolution, which allows for direct analysis of the transition states from the FRET time trace using hidden Markov modelling. We measure transition rates of up to 1,500 s-1 between two conformers of a Holliday junction. The rapid diffusional migration of Deinococcus radiodurans single-stranded DNA-binding protein (SSB) on single-stranded DNA is resolved by FRET, faster than that of Escherichia coli SSB by an order of magnitude. Our approach is a powerful method for studying the dynamics and movements of biomolecules at submillisecond resolution.

  13. Real-time dynamics of high-velocity micro-particle impact

    NASA Astrophysics Data System (ADS)

    Veysset, David; Hsieh, Alex; Kooi, Steve; Maznev, Alex A.; Tang, Shengchang; Olsen, Bradley D.; Nelson, Keith A.

    High-velocity micro-particle impact is important for many areas of science and technology, from space exploration to the development of novel drug delivery platforms. We present real-time observations of supersonic micro-particle impacts using multi-frame imaging. In an all optical laser-induced projectile impact test, a monolayer of micro-particles is placed on a transparent substrate coated with a laser absorbing polymer layer. Ablation of a laser-irradiated polymer region accelerates the micro-particles into free space with speeds up to 1.0 km/s. The particles are monitored during the impact on the target with an ultrahigh-speed multi-frame camera that can record up to 16 images with time resolution as short as 3 ns. In particular, we investigated the high-velocity impact deformation response of poly(urethane urea) (PUU) elastomers to further the fundamental understanding of the molecular influence on dynamical behaviors of PUUs. We show the dynamic-stiffening response of the PUUs and demonstrate the significance of segmental dynamics in the response. We also present movies capturing individual particle impact and penetration in gels, and discuss the observed dynamics. The results will provide an impetus for modeling high-velocity microscale impact responses and high strain rate deformation in polymers, gels, and other materials.

  14. A Sarsa(λ)-based control model for real-time traffic light coordination.

    PubMed

    Zhou, Xiaoke; Zhu, Fei; Liu, Quan; Fu, Yuchen; Huang, Wei

    2014-01-01

    Traffic problems often occur due to the traffic demands by the outnumbered vehicles on road. Maximizing traffic flow and minimizing the average waiting time are the goals of intelligent traffic control. Each junction wants to get larger traffic flow. During the course, junctions form a policy of coordination as well as constraints for adjacent junctions to maximize their own interests. A good traffic signal timing policy is helpful to solve the problem. However, as there are so many factors that can affect the traffic control model, it is difficult to find the optimal solution. The disability of traffic light controllers to learn from past experiences caused them to be unable to adaptively fit dynamic changes of traffic flow. Considering dynamic characteristics of the actual traffic environment, reinforcement learning algorithm based traffic control approach can be applied to get optimal scheduling policy. The proposed Sarsa(λ)-based real-time traffic control optimization model can maintain the traffic signal timing policy more effectively. The Sarsa(λ)-based model gains traffic cost of the vehicle, which considers delay time, the number of waiting vehicles, and the integrated saturation from its experiences to learn and determine the optimal actions. The experiment results show an inspiring improvement in traffic control, indicating the proposed model is capable of facilitating real-time dynamic traffic control.

  15. A Sarsa(λ)-Based Control Model for Real-Time Traffic Light Coordination

    PubMed Central

    Zhu, Fei; Liu, Quan; Fu, Yuchen; Huang, Wei

    2014-01-01

    Traffic problems often occur due to the traffic demands by the outnumbered vehicles on road. Maximizing traffic flow and minimizing the average waiting time are the goals of intelligent traffic control. Each junction wants to get larger traffic flow. During the course, junctions form a policy of coordination as well as constraints for adjacent junctions to maximize their own interests. A good traffic signal timing policy is helpful to solve the problem. However, as there are so many factors that can affect the traffic control model, it is difficult to find the optimal solution. The disability of traffic light controllers to learn from past experiences caused them to be unable to adaptively fit dynamic changes of traffic flow. Considering dynamic characteristics of the actual traffic environment, reinforcement learning algorithm based traffic control approach can be applied to get optimal scheduling policy. The proposed Sarsa(λ)-based real-time traffic control optimization model can maintain the traffic signal timing policy more effectively. The Sarsa(λ)-based model gains traffic cost of the vehicle, which considers delay time, the number of waiting vehicles, and the integrated saturation from its experiences to learn and determine the optimal actions. The experiment results show an inspiring improvement in traffic control, indicating the proposed model is capable of facilitating real-time dynamic traffic control. PMID:24592183

  16. Real-time image processing for non-contact monitoring of dynamic displacements using smartphone technologies

    NASA Astrophysics Data System (ADS)

    Min, Jae-Hong; Gelo, Nikolas J.; Jo, Hongki

    2016-04-01

    The newly developed smartphone application, named RINO, in this study allows measuring absolute dynamic displacements and processing them in real time using state-of-the-art smartphone technologies, such as high-performance graphics processing unit (GPU), in addition to already powerful CPU and memories, embedded high-speed/ resolution camera, and open-source computer vision libraries. A carefully designed color-patterned target and user-adjustable crop filter enable accurate and fast image processing, allowing up to 240fps for complete displacement calculation and real-time display. The performances of the developed smartphone application are experimentally validated, showing comparable accuracy with those of conventional laser displacement sensor.

  17. Real Time Tracking of Magmatic Intrusions by means of Ground Deformation Modeling during Volcanic Crises

    PubMed Central

    Cannavò, Flavio; Camacho, Antonio G.; González, Pablo J.; Mattia, Mario; Puglisi, Giuseppe; Fernández, José

    2015-01-01

    Volcano observatories provide near real-time information and, ultimately, forecasts about volcano activity. For this reason, multiple physical and chemical parameters are continuously monitored. Here, we present a new method to efficiently estimate the location and evolution of magmatic sources based on a stream of real-time surface deformation data, such as High-Rate GPS, and a free-geometry magmatic source model. The tool allows tracking inflation and deflation sources in time, providing estimates of where a volcano might erupt, which is important in understanding an on-going crisis. We show a successful simulated application to the pre-eruptive period of May 2008, at Mount Etna (Italy). The proposed methodology is able to track the fast dynamics of the magma migration by inverting the real-time data within seconds. This general method is suitable for integration in any volcano observatory. The method provides first order unsupervised and realistic estimates of the locations of magmatic sources and of potential eruption sites, information that is especially important for civil protection purposes. PMID:26055494

  18. Real Time Tracking of Magmatic Intrusions by means of Ground Deformation Modeling during Volcanic Crises.

    PubMed

    Cannavò, Flavio; Camacho, Antonio G; González, Pablo J; Mattia, Mario; Puglisi, Giuseppe; Fernández, José

    2015-06-09

    Volcano observatories provide near real-time information and, ultimately, forecasts about volcano activity. For this reason, multiple physical and chemical parameters are continuously monitored. Here, we present a new method to efficiently estimate the location and evolution of magmatic sources based on a stream of real-time surface deformation data, such as High-Rate GPS, and a free-geometry magmatic source model. The tool allows tracking inflation and deflation sources in time, providing estimates of where a volcano might erupt, which is important in understanding an on-going crisis. We show a successful simulated application to the pre-eruptive period of May 2008, at Mount Etna (Italy). The proposed methodology is able to track the fast dynamics of the magma migration by inverting the real-time data within seconds. This general method is suitable for integration in any volcano observatory. The method provides first order unsupervised and realistic estimates of the locations of magmatic sources and of potential eruption sites, information that is especially important for civil protection purposes.

  19. Real Time Tracking of Magmatic Intrusions by means of Ground Deformation Modeling during Volcanic Crises

    NASA Astrophysics Data System (ADS)

    Cannavò, Flavio; Camacho, Antonio G.; González, Pablo J.; Mattia, Mario; Puglisi, Giuseppe; Fernández, José

    2015-06-01

    Volcano observatories provide near real-time information and, ultimately, forecasts about volcano activity. For this reason, multiple physical and chemical parameters are continuously monitored. Here, we present a new method to efficiently estimate the location and evolution of magmatic sources based on a stream of real-time surface deformation data, such as High-Rate GPS, and a free-geometry magmatic source model. The tool allows tracking inflation and deflation sources in time, providing estimates of where a volcano might erupt, which is important in understanding an on-going crisis. We show a successful simulated application to the pre-eruptive period of May 2008, at Mount Etna (Italy). The proposed methodology is able to track the fast dynamics of the magma migration by inverting the real-time data within seconds. This general method is suitable for integration in any volcano observatory. The method provides first order unsupervised and realistic estimates of the locations of magmatic sources and of potential eruption sites, information that is especially important for civil protection purposes.

  20. Substructurability: the effect of interface location on a real-time dynamic substructuring test

    PubMed Central

    Neild, S. A.; Lowenberg, M.; Szalai, R.; Krauskopf, B.

    2016-01-01

    A full-scale experimental test for large and complex structures is not always achievable. This can be due to many reasons, the most prominent one being the size limitations of the test. Real-time dynamic substructuring is a hybrid testing method where part of the system is modelled numerically and the rest of the system is kept as the physical test specimen. The numerical–physical parts are connected via actuators and sensors and the interface is controlled by advanced algorithms to ensure that the tested structure replicates the emulated system with sufficient accuracy. The main challenge in such a test is to overcome the dynamic effects of the actuator and associated controller, that inevitably introduce delay into the substructured system which, in turn, can destabilize the experiment. To date, most research concentrates on developing control strategies for stable recreation of the full system when the interface location is given a priori. Therefore, substructurability is mostly studied in terms of control. Here, we consider the interface location as a parameter and study its effect on the stability of the system in the presence of delay due to actuator dynamics and define substructurability as the system’s tolerance to delay in terms of the different interface locations. It is shown that the interface location has a major effect on the tolerable delays in an experiment and, therefore, careful selection of it is necessary. PMID:27616930

  1. Substructurability: the effect of interface location on a real-time dynamic substructuring test.

    PubMed

    Terkovics, N; Neild, S A; Lowenberg, M; Szalai, R; Krauskopf, B

    2016-08-01

    A full-scale experimental test for large and complex structures is not always achievable. This can be due to many reasons, the most prominent one being the size limitations of the test. Real-time dynamic substructuring is a hybrid testing method where part of the system is modelled numerically and the rest of the system is kept as the physical test specimen. The numerical-physical parts are connected via actuators and sensors and the interface is controlled by advanced algorithms to ensure that the tested structure replicates the emulated system with sufficient accuracy. The main challenge in such a test is to overcome the dynamic effects of the actuator and associated controller, that inevitably introduce delay into the substructured system which, in turn, can destabilize the experiment. To date, most research concentrates on developing control strategies for stable recreation of the full system when the interface location is given a priori. Therefore, substructurability is mostly studied in terms of control. Here, we consider the interface location as a parameter and study its effect on the stability of the system in the presence of delay due to actuator dynamics and define substructurability as the system's tolerance to delay in terms of the different interface locations. It is shown that the interface location has a major effect on the tolerable delays in an experiment and, therefore, careful selection of it is necessary.

  2. VTI Driving Simulator: Mathematical Model of a Four-wheeled Vehicle for Simulation in Real Time. VTI Rapport 267A.

    ERIC Educational Resources Information Center

    Nordmark, Staffan

    1984-01-01

    This report contains a theoretical model for describing the motion of a passenger car. The simulation program based on this model is used in conjunction with an advanced driving simulator and run in real time. The mathematical model is complete in the sense that the dynamics of the engine, transmission and steering system is described in some…

  3. Automatic mathematical modeling for real time simulation program (AI application)

    NASA Technical Reports Server (NTRS)

    Wang, Caroline; Purinton, Steve

    1989-01-01

    A methodology is described for automatic mathematical modeling and generating simulation models. The major objective was to create a user friendly environment for engineers to design, maintain, and verify their models; to automatically convert the mathematical models into conventional code for computation; and finally, to document the model automatically.

  4. Nonequilibrium study of the chiral magnetic effect from real-time simulations with dynamical fermions

    NASA Astrophysics Data System (ADS)

    Mace, Mark; Mueller, Niklas; Schlichting, Sören; Sharma, Sayantan

    2017-02-01

    We present a real-time lattice approach to study the nonequilibrium dynamics of vector and axial charges in S U (N )×U (1 ) gauge theories. Based on a classical description of the non-Abelian and Abelian gauge fields, we include dynamical fermions and develop operator definitions for (improved) Wilson and overlap fermions that allow us to study real-time manifestations of the axial anomaly from first principles. We present a first application of this approach to anomalous transport phenomena such as the chiral magnetic effect (CME) and the chiral separation effect (CSE) by studying the dynamics of fermions during and after a S U (N ) sphaleron transition in the presence of a U (1 ) magnetic field. We investigate the fermion mass and magnetic field dependence of the suggested signatures of the CME and the CSE and point out some important aspects which need to be accounted for in the macroscopic description of anomalous transport phenomena.

  5. Real-Time Description of the Electronic Dynamics for a Molecule Close to a Plasmonic Nanoparticle

    PubMed Central

    2016-01-01

    The optical properties of molecules close to plasmonic nanostructures greatly differ from their isolated molecule counterparts. To theoretically investigate such systems from a quantum-chemistry perspective, one has to take into account that the plasmonic nanostructure (e.g., a metal nanoparticle–NP) is often too large to be treated atomistically. Therefore, a multiscale description, where the molecule is treated by an ab initio approach and the metal NP by a lower level description, is needed. Here we present an extension of one such multiscale model [Corni, S.; Tomasi, J. J. Chem. Phys.2001, 114, 3739], originally inspired by the polarizable continuum model, to a real-time description of the electronic dynamics of the molecule and of the NP. In particular, we adopt a time-dependent configuration interaction (TD CI) approach for the molecule, the metal NP is described as a continuous dielectric of complex shape characterized by a Drude–Lorentz dielectric function, and the molecule–NP electromagnetic coupling is treated by an equation-of-motion (EOM) extension of the quasi-static boundary element method (BEM). The model includes the effects of both the mutual molecule–NP time-dependent polarization and the modification of the probing electromagnetic field due to the plasmonic resonances of the NP. Finally, such an approach is applied to the investigation of the light absorption of a model chromophore, LiCN, in the presence of a metal–NP of complex shape. PMID:28035246

  6. Efficient DMFT impurity solver using real-time dynamics with matrix product states

    NASA Astrophysics Data System (ADS)

    Ganahl, Martin; Aichhorn, Markus; Evertz, Hans Gerd; Thunström, Patrik; Held, Karsten; Verstraete, Frank

    2015-10-01

    We propose to calculate spectral functions of quantum impurity models using the time evolving block decimation (TEBD) for matrix product states. The resolution of the spectral function is improved by a so-called linear prediction approach. We apply the method as an impurity solver within the dynamical mean-field theory (DMFT) for the single- and two-band Hubbard model on the Bethe lattice. For the single-band model, we observe sharp features at the inner edges of the Hubbard bands. A finite-size scaling shows that they remain present in the thermodynamic limit. We analyze the real time-dependence of the double occupation after adding a single electron and observe oscillations at the same energy as the sharp feature in the Hubbard band, indicating a long-lived coherent superposition of states that correspond to the Kondo peak and the side peaks. For a two-band Hubbard model, we observe an even richer structure in the Hubbard bands, which cannot be related to a multiplet structure of the impurity, in addition to sharp excitations at the band edges of a type similar to the single-band case.

  7. Estimating Model Parameters of Adaptive Software Systems in Real-Time

    NASA Astrophysics Data System (ADS)

    Kumar, Dinesh; Tantawi, Asser; Zhang, Li

    Adaptive software systems have the ability to adapt to changes in workload and execution environment. In order to perform resource management through model based control in such systems, an accurate mechanism for estimating the software system's model parameters is required. This paper deals with real-time estimation of a performance model for adaptive software systems that process multiple classes of transactional workload. First, insights in to the static performance model estimation problem are provided. Then an Extended Kalman Filter (EKF) design is combined with an open queueing network model to dynamically estimate the model parameters in real-time. Specific problems that are encountered in the case of multiple classes of workload are analyzed. These problems arise mainly due to the under-deterministic nature of the estimation problem. This motivates us to propose a modified design of the filter. Insights for choosing tuning parameters of the modified design, i.e., number of constraints and sampling intervals are provided. The modified filter design is shown to effectively tackle problems with multiple classes of workload through experiments.

  8. Real-time dynamics simulation of the Cassini spacecraft using DARTS. Part 1: Functional capabilities and the spatial algebra algorithm

    NASA Technical Reports Server (NTRS)

    Jain, A.; Man, G. K.

    1993-01-01

    This paper describes the Dynamics Algorithms for Real-Time Simulation (DARTS) real-time hardware-in-the-loop dynamics simulator for the National Aeronautics and Space Administration's Cassini spacecraft. The spacecraft model consists of a central flexible body with a number of articulated rigid-body appendages. The demanding performance requirements from the spacecraft control system require the use of a high fidelity simulator for control system design and testing. The DARTS algorithm provides a new algorithmic and hardware approach to the solution of this hardware-in-the-loop simulation problem. It is based upon the efficient spatial algebra dynamics for flexible multibody systems. A parallel and vectorized version of this algorithm is implemented on a low-cost, multiprocessor computer to meet the simulation timing requirements.

  9. Learning Models and Real-Time Speech Recognition.

    ERIC Educational Resources Information Center

    Danforth, Douglas G.; And Others

    This report describes the construction and testing of two "psychological" learning models for the purpose of computer recognition of human speech over the telephone. One of the two models was found to be superior in all tests. A regression analysis yielded a 92.3% recognition rate for 14 subjects ranging in age from 6 to 13 years. Tests…

  10. Revealing Real-Time Emotional Responses: a Personalized Assessment based on Heartbeat Dynamics

    PubMed Central

    Valenza, Gaetano; Citi, Luca; Lanatá, Antonio; Scilingo, Enzo Pasquale; Barbieri, Riccardo

    2014-01-01

    Emotion recognition through computational modeling and analysis of physiological signals has been widely investigated in the last decade. Most of the proposed emotion recognition systems require relatively long-time series of multivariate records and do not provide accurate real-time characterizations using short-time series. To overcome these limitations, we propose a novel personalized probabilistic framework able to characterize the emotional state of a subject through the analysis of heartbeat dynamics exclusively. The study includes thirty subjects presented with a set of standardized images gathered from the international affective picture system, alternating levels of arousal and valence. Due to the intrinsic nonlinearity and nonstationarity of the RR interval series, a specific point-process model was devised for instantaneous identification considering autoregressive nonlinearities up to the third-order according to the Wiener-Volterra representation, thus tracking very fast stimulus-response changes. Features from the instantaneous spectrum and bispectrum, as well as the dominant Lyapunov exponent, were extracted and considered as input features to a support vector machine for classification. Results, estimating emotions each 10 seconds, achieve an overall accuracy in recognizing four emotional states based on the circumplex model of affect of 79.29%, with 79.15% on the valence axis, and 83.55% on the arousal axis. PMID:24845973

  11. Robust human detection within a highly dynamic aquatic environment in real time.

    PubMed

    Eng, How-Lung; Wang, Junxian; Wah, Alvin Harvey Kam Siew; Yau, Wei-Yun

    2006-06-01

    This paper presents a real-time foreground detection method for monitoring swimming activities at an outdoor swimming pool. Robust performance and high accuracy of detecting objects-of-interest are two central issues of concern. Therefore, in this paper, a considerable amount of attention has been placed on the following aspects: 1) to establish a better method of modeling aquatic background, which exhibitis dynamic characteristics with random spatial movements, and 2) to establish a method of enhancing the visibility of the foreground by removing specular reflection at nighttime. First, the development of a new background modeling method is reported. In the proposed approach, the background is modeled as a composition of homogeneous blob movements. With an implementation of a spatial searching process, the proposed method shows capability in associating and distinguishing movements caused by the background. Hence, this contributes to better performance in foreground detection. On the issue of enhancing the visibility of the foreground, a decision-based filtering scheme is proposed as a preprocessing step. A defined concept term, fluctuation measure, is defined for classifying each pixel to be one of the predefined types. This has allowed suitable spatial or spatiotemporal filters to be applied accordingly for color the compensation step. All of these developments are evaluated by testing live on a busy Olympic-size outdoor public swimming pool. Both qualitative and quantitative evaluations are reported. This provides a comprehensive study of the system.

  12. Real-time imaging of glutamate clearance reveals normal striatal uptake in Huntington disease mouse models.

    PubMed

    Parsons, Matthew P; Vanni, Matthieu P; Woodard, Cameron L; Kang, Rujun; Murphy, Timothy H; Raymond, Lynn A

    2016-04-07

    It has become well accepted that Huntington disease (HD) is associated with impaired glutamate uptake, resulting in a prolonged time-course of extracellular glutamate that contributes to excitotoxicity. However, the data supporting this view come largely from work in synaptosomes, which may overrepresent nerve-terminal uptake over astrocytic uptake. Here, we quantify real-time glutamate dynamics in HD mouse models by high-speed imaging of an intensity-based glutamate-sensing fluorescent reporter (iGluSnFR) and electrophysiological recordings of synaptically activated transporter currents in astrocytes. These techniques reveal a disconnect between the results obtained in synaptosomes and those in situ. Exogenous glutamate uptake is impaired in synaptosomes, whereas real-time measures of glutamate clearance in the HD striatum are normal or even accelerated, particularly in the aggressive R6/2 model. Our results highlight the importance of quantifying glutamate dynamics under endogenous release conditions, and suggest that the widely cited uptake impairment in HD does not contribute to pathogenesis.

  13. Real-time imaging of glutamate clearance reveals normal striatal uptake in Huntington disease mouse models

    PubMed Central

    Parsons, Matthew P.; Vanni, Matthieu P.; Woodard, Cameron L.; Kang, Rujun; Murphy, Timothy H.; Raymond, Lynn A.

    2016-01-01

    It has become well accepted that Huntington disease (HD) is associated with impaired glutamate uptake, resulting in a prolonged time-course of extracellular glutamate that contributes to excitotoxicity. However, the data supporting this view come largely from work in synaptosomes, which may overrepresent nerve-terminal uptake over astrocytic uptake. Here, we quantify real-time glutamate dynamics in HD mouse models by high-speed imaging of an intensity-based glutamate-sensing fluorescent reporter (iGluSnFR) and electrophysiological recordings of synaptically activated transporter currents in astrocytes. These techniques reveal a disconnect between the results obtained in synaptosomes and those in situ. Exogenous glutamate uptake is impaired in synaptosomes, whereas real-time measures of glutamate clearance in the HD striatum are normal or even accelerated, particularly in the aggressive R6/2 model. Our results highlight the importance of quantifying glutamate dynamics under endogenous release conditions, and suggest that the widely cited uptake impairment in HD does not contribute to pathogenesis. PMID:27052848

  14. Real-Time Global Nonlinear Aerodynamic Modeling for Learn-To-Fly

    NASA Technical Reports Server (NTRS)

    Morelli, Eugene A.

    2016-01-01

    Flight testing and modeling techniques were developed to accurately identify global nonlinear aerodynamic models for aircraft in real time. The techniques were developed and demonstrated during flight testing of a remotely-piloted subscale propeller-driven fixed-wing aircraft using flight test maneuvers designed to simulate a Learn-To-Fly scenario. Prediction testing was used to evaluate the quality of the global models identified in real time. The real-time global nonlinear aerodynamic modeling algorithm will be integrated and further tested with learning adaptive control and guidance for NASA Learn-To-Fly concept flight demonstrations.

  15. Model for LMFBR core transient analysis in real-time

    SciTech Connect

    Tzanos, C.P.

    1986-01-01

    This paper discusses the modeling of LMFBR core transients. It is shown that with a proper choice of shape functions a nodal approximation of the coolant, cladding, and fuel temperature distributions leads to adequately accurate power and temperature predictions, as well as adequately short computation times.

  16. Model compilation for embedded real-time planning and diagnosis

    NASA Technical Reports Server (NTRS)

    Barrett, Anthony

    2004-01-01

    This paper describes MEXEC, an implemented micro executive that compiles a device model into an interal structure. Not only does this structure facilitate computing the most likely current device mode from n sets of sensor measurements, but it also facilitates generating an n step reconfiguration plan that is most likely not to result in reaching a target mode - if such a plan exists.

  17. A dynamical systems perspective for a real-time response to a marine oil spill.

    PubMed

    García-Garrido, V J; Ramos, A; Mancho, A M; Coca, J; Wiggins, S

    2016-11-15

    This paper discusses the combined use of tools from dynamical systems theory and remote sensing techniques and shows how they are effective instruments which may greatly contribute to the decision making protocols of the emergency services for the real-time management of oil spills. This work presents the successful interplay of these techniques for a recent situation, the sinking of the Oleg Naydenov fishing ship that took place in Spain, close to the Canary Islands, in April 2015.

  18. Empirical modeling for intelligent, real-time manufacture control

    NASA Technical Reports Server (NTRS)

    Xu, Xiaoshu

    1994-01-01

    Artificial neural systems (ANS), also known as neural networks, are an attempt to develop computer systems that emulate the neural reasoning behavior of biological neural systems (e.g. the human brain). As such, they are loosely based on biological neural networks. The ANS consists of a series of nodes (neurons) and weighted connections (axons) that, when presented with a specific input pattern, can associate specific output patterns. It is essentially a highly complex, nonlinear, mathematical relationship or transform. These constructs have two significant properties that have proven useful to the authors in signal processing and process modeling: noise tolerance and complex pattern recognition. Specifically, the authors have developed a new network learning algorithm that has resulted in the successful application of ANS's to high speed signal processing and to developing models of highly complex processes. Two of the applications, the Weld Bead Geometry Control System and the Welding Penetration Monitoring System, are discussed in the body of this paper.

  19. Method of modeling transmissions for real-time simulation

    DOEpatents

    Hebbale, Kumaraswamy V.

    2012-09-25

    A transmission modeling system includes an in-gear module that determines an in-gear acceleration when a vehicle is in gear. A shift module determines a shift acceleration based on a clutch torque when the vehicle is shifting between gears. A shaft acceleration determination module determines a shaft acceleration based on at least one of the in-gear acceleration and the shift acceleration.

  20. Tactical Atmospheric Modeling System-Real Time (TAMS-RT)

    DTIC Science & Technology

    2016-06-07

    purpose of this award was to enhance the demonstration by supporting execution of tactical decision aids (TDA) using the organic high-resolution...and Windows Electro-Optical Tactical Decision Aid (EOTDA) programs at NCMOC and link to the TEDS database for the model fields. APPROACH Since...mesoscale features influenced by complex terrain, and the use of the resultant data by decision aids will be of great value to the Navy by improving

  1. Real-time robot path planning based on a modified pulse-coupled neural network model.

    PubMed

    Qu, Hong; Yang, Simon X; Willms, Allan R; Yi, Zhang

    2009-11-01

    This paper presents a modified pulse-coupled neural network (MPCNN) model for real-time collision-free path planning of mobile robots in nonstationary environments. The proposed neural network for robots is topologically organized with only local lateral connections among neurons. It works in dynamic environments and requires no prior knowledge of target or barrier movements. The target neuron fires first, and then the firing event spreads out, through the lateral connections among the neurons, like the propagation of a wave. Obstacles have no connections to their neighbors. Each neuron records its parent, that is, the neighbor that caused it to fire. The real-time optimal path is then the sequence of parents from the robot to the target. In a static case where the barriers and targets are stationary, this paper proves that the generated wave in the network spreads outward with travel times proportional to the linking strength among neurons. Thus, the generated path is always the global shortest path from the robot to the target. In addition, each neuron in the proposed model can propagate a firing event to its neighboring neuron without any comparing computations. The proposed model is applied to generate collision-free paths for a mobile robot to solve a maze-type problem, to circumvent concave U-shaped obstacles, and to track a moving target in an environment with varying obstacles. The effectiveness and efficiency of the proposed approach is demonstrated through simulation and comparison studies.

  2. Real-time C Code Generation in Ptolemy II for the Giotto Model of Computation

    DTIC Science & Technology

    2009-05-20

    Real-time C Code Generation in Ptolemy II for the Giotto Model of Computation Shanna-Shaye Forbes Electrical Engineering and Computer Sciences...MAY 2009 2. REPORT TYPE 3. DATES COVERED 00-00-2009 to 00-00-2009 4. TITLE AND SUBTITLE Real-time C Code Generation in Ptolemy II for the Giotto...periodic and there are multiple modes of operation. Ptolemy II is a university based open source modeling and simulation framework that supports model

  3. A Comparison and Evaluation of Real-Time Software Systems Modeling Languages

    NASA Technical Reports Server (NTRS)

    Evensen, Kenneth D.; Weiss, Kathryn Anne

    2010-01-01

    A model-driven approach to real-time software systems development enables the conceptualization of software, fostering a more thorough understanding of its often complex architecture and behavior while promoting the documentation and analysis of concerns common to real-time embedded systems such as scheduling, resource allocation, and performance. Several modeling languages have been developed to assist in the model-driven software engineering effort for real-time systems, and these languages are beginning to gain traction with practitioners throughout the aerospace industry. This paper presents a survey of several real-time software system modeling languages, namely the Architectural Analysis and Design Language (AADL), the Unified Modeling Language (UML), Systems Modeling Language (SysML), the Modeling and Analysis of Real-Time Embedded Systems (MARTE) UML profile, and the AADL for UML profile. Each language has its advantages and disadvantages, and in order to adequately describe a real-time software system's architecture, a complementary use of multiple languages is almost certainly necessary. This paper aims to explore these languages in the context of understanding the value each brings to the model-driven software engineering effort and to determine if it is feasible and practical to combine aspects of the various modeling languages to achieve more complete coverage in architectural descriptions. To this end, each language is evaluated with respect to a set of criteria such as scope, formalisms, and architectural coverage. An example is used to help illustrate the capabilities of the various languages.

  4. Real-time tracking mitochondrial dynamic remodeling with two-photon phosphorescent iridium (III) complexes.

    PubMed

    Huang, Huaiyi; Yang, Liang; Zhang, Pingyu; Qiu, Kangqiang; Huang, Juanjuan; Chen, Yu; Diao, JiaJie; Liu, Jiankang; Ji, Liangnian; Long, Jiangang; Chao, Hui

    2016-03-01

    Mitochondrial fission and fusion control the shape, size, number, and function of mitochondria in the cells of organisms from yeast to mammals. The disruption of mitochondrial fission and fusion is involved in severe human diseases such as Parkinson's disease, Alzheimer's disease, metabolic diseases, and cancers. Agents that can real-time track the mitochondrial dynamics are of great importance. However, the short excitation wavelengths and rapidly photo-bleaching properties of commercial mitochondrial dyes render them unsuitable for tracking mitochondrial dynamics. Thus, mitochondrial targeting agents that exhibit superior photo-stability under continual light irradiation, deep tissue penetration and at intrinsically high three-dimensional resolutions are urgently needed. Two-photon-excited compounds employ low-energy near-infrared light and have emerged as a non-invasive tool for real-time cell imaging. Here, cyclometalated Ir(III) complexes (Ir1-Ir5) are demonstrated as one- and two-photon phosphorescent probes for the real-time imaging and tracking of mitochondrial fission and fusion. The results indicate that Ir2 is well suited for two-photon phosphorescent tracking of mitochondrial fission and fusion in living cells and in Caenorhabditis elegans (C. elegans). This study provides a practical use for mitochondrial targeting two-photon phosphorescent Ir(III) complexes.

  5. Monte Carlo Study of Real Time Dynamics on the Lattice.

    PubMed

    Alexandru, Andrei; Başar, Gökçe; Bedaque, Paulo F; Vartak, Sohan; Warrington, Neill C

    2016-08-19

    Monte Carlo studies involving real time dynamics are severely restricted by the sign problem that emerges from a highly oscillatory phase of the path integral. In this Letter, we present a new method to compute real time quantities on the lattice using the Schwinger-Keldysh formalism via Monte Carlo simulations. The key idea is to deform the path integration domain to a complex manifold where the phase oscillations are mild and the sign problem is manageable. We use the previously introduced "contraction algorithm" to create a Markov chain on this alternative manifold. We substantiate our approach by analyzing the quantum mechanical anharmonic oscillator. Our results are in agreement with the exact ones obtained by diagonalization of the Hamiltonian. The method we introduce is generic and, in principle, applicable to quantum field theory albeit very slow. We discuss some possible improvements that should speed up the algorithm.

  6. Dynamical theory of spin noise and relaxation: Prospects for real-time NMR measurements.

    PubMed

    Field, Timothy R

    2014-11-01

    Recent developments in theoretical aspects of spin noise and relaxation and their interrelationship reveal a modified spin density, distinct from the density matrix, as the necessary object to describe fluctuations in spin systems. These fluctuations are to be viewed as an intrinsic quantum mechanical property of such systems immersed in random magnetic environments and are observed as "spin noise" in the absence of any radio frequency excitation. With the prospect of ultrafast digitization, the role of spin noise in real-time parameter extraction for (NMR) spin systems, and the advantage over standard techniques, is of essential importance, especially for systems containing a small number of spins. In this article we outline prospects for harnessing the recent dynamical theory in terms of spin-noise measurement, with attention to real-time properties.

  7. Real-time visualization of excited-state dynamics in molecular chains

    NASA Astrophysics Data System (ADS)

    Li, Yonghui; Ullrich, Carsten

    2011-03-01

    Time-dependent density-functional theory allows one to calculate excitation energies and the associated transition densities in principle exactly. The transition density matrix (TDM) provides additional information on electron-hole localization and coherence of a specific excitation. We have extended the TDM concept into the real-time domain in order to visualize the excited-state dynamics in conjugated molecules. Our computational scheme is based on solving the time-dependent Kohn-Sham equations with the OCTOPUS code and then calculating the time-dependent Kohn-Sham TDM using a spatial partitioning scheme. The method is applied to show in real time how locally created electron-hole pairs spread out over neighboring conjugated molecular chains. The coupling mechanism, electron-hole coherence, and the possibility of charge separation are discussed. This work is supported by NSF Grants DMR-0553485 and DMR-1005651.

  8. Dynamic Scheduling Real-Time Task Using Primary-Backup Overloading Strategy for Multiprocessor Systems

    NASA Astrophysics Data System (ADS)

    Sun, Wei; Yu, Chen; Défago, Xavier; Inoguchi, Yasushi

    The scheduling of real-time tasks with fault-tolerant requirements has been an important problem in multiprocessor systems. The primary-backup (PB) approach is often used as a fault-tolerant technique to guarantee the deadlines of tasks despite the presence of faults. In this paper we propose a dynamic PB-based task scheduling approach, wherein an allocation parameter is used to search the available time slots for a newly arriving task, and the previously scheduled tasks can be re-scheduled when there is no available time slot for the newly arriving task. In order to improve the schedulability we also propose an overloading strategy for PB-overloading and Backup-backup (BB) overloading. Our proposed task scheduling algorithm is compared with some existing scheduling algorithms in the literature through simulation studies. The results have shown that the task rejection ratio of our real-time task scheduling algorithm is almost 50% lower than the compared algorithms.

  9. Imaging Excited-State Dynamics of Doped He Nanodroplets in Real-Time.

    PubMed

    von Vangerow, Johannes; Coppens, François; Leal, Antonio; Pi, Martí; Barranco, Manuel; Halberstadt, Nadine; Stienkemeier, Frank; Mudrich, Marcel

    2017-01-05

    The real-time dynamics of excited alkali metal atoms (Rb) attached to quantum fluid He nanodroplets is investigated using femtosecond imaging spectroscopy and time-dependent density functional theory. We disentangle the competing dynamics of desorption of excited Rb atoms off the He droplet surface and solvation inside the droplet interior as the Rb atom is ionized. For Rb excited to the 5p and 6p states, desorption occurs on starkly differing time scales (∼100 versus ∼1 ps, respectively). The comparison between theory and experiment indicates that desorption proceeds either impulsively (6p) or in a transition regime between impulsive dissociation and complex desorption (5p).

  10. Physically-Based Modelling and Real-Time Simulation of Fluids.

    NASA Astrophysics Data System (ADS)

    Chen, Jim Xiong

    1995-01-01

    Simulating physically realistic complex fluid behaviors presents an extremely challenging problem for computer graphics researchers. Such behaviors include the effects of driving boats through water, blending differently colored fluids, rain falling and flowing on a terrain, fluids interacting in a Distributed Interactive Simulation (DIS), etc. Such capabilities are useful in computer art, advertising, education, entertainment, and training. We present a new method for physically-based modeling and real-time simulation of fluids in computer graphics and dynamic virtual environments. By solving the 2D Navier -Stokes equations using a CFD method, we map the surface into 3D using the corresponding pressures in the fluid flow field. This achieves realistic real-time fluid surface behaviors by employing the physical governing laws of fluids but avoiding extensive 3D fluid dynamics computations. To complement the surface behaviors, we calculate fluid volume and external boundary changes separately to achieve full 3D general fluid flow. To simulate physical activities in a DIS, we introduce a mechanism which uses a uniform time scale proportional to the clock-time and variable time-slicing to synchronize physical models such as fluids in the networked environment. Our approach can simulate many different fluid behaviors by changing the internal or external boundary conditions. It can model different kinds of fluids by varying the Reynolds number. It can simulate objects moving or floating in fluids. It can also produce synchronized general fluid flows in a DIS. Our model can serve as a testbed to simulate many other fluid phenomena which have never been successfully modeled previously.

  11. Extended kinetic model of real-time polymerase chain reaction process

    NASA Astrophysics Data System (ADS)

    Fedorov, A. A.; Sochivko, D. G.; Varlamov, D. A.; Kurochkin, V. E.

    2016-11-01

    Real-time polymerase chain reaction (real-time PCR) is the main molecular genetic method used for qualitative and quantitative analysis of specific nucleic acid sequences in many areas of biomedical research. Theoretical study of pCr models allows to estimate the influence of various reaction components and parameters, and to determine the unknown parameter values by approximating the experimental real-time PCR curves. An extended kinetic model of real-time PCR is presented. The model takes into account the enzyme activity based on Michaelis-Menten kinetics, the hybridization of complementary DNA fragments, the presence of a fluorescent probe used for detection of the reaction products, and the temperature dependence of primers and probe hybridization.

  12. Exact real-time dynamics of electron transport in mesoscopic systems

    NASA Astrophysics Data System (ADS)

    Zheng, Xiao; Jin, Jinshuang; Yan, Yijing

    2009-03-01

    We present a formally exact and numerically tractable quantum dissipation theory for time-dependent quantum transport in mesoscopic systems. It is formulated in terms of hierarchically coupled equations of motion, which govern the non-Markovian dynamics of an arbitrary fermionic system interacting with grand canonical electron reservoirs, in the presence of arbitrary time-dependent applied voltages [1-2]. We also present numerical results on the real-time dynamics of open quantum dot systems. The linear response admittance is mapped to classical equivalent circuits; while the nonlinear response dynamics is associated with dot-state transitions, such as the dynamic Coulomb blockade effect involved in interacting quantum dots [3-4]. Real-time Kondo phenomena are also demonstrated, with the cotunneling induced Kondo transition distinguished in the transient response current. This work highlights the significance and versatility of quantum dissipation theory for transient dynamics calculations. [1] J. S. Jin, S. Welack, J. Y. Luo, X. Q. Li, P. Cui, R. X. Xu, and Y. J. Yan, J. Chem. Phys. 126, 134113 (2007). [2] J. S. Jin, X. Zheng, and Y. J. Yan, J. Chem. Phys. 128, 234703 (2008). [3] X. Zheng, J. S. Jin, and Y. J. Yan, J. Chem. Phys. 129, 184112 (2008). [4] X. Zheng, J. S. Jin, and Y. J. Yan, New J. Phys. 10, 093016 (2008).

  13. Review of Real-Time Simulator and the Steps Involved for Implementation of a Model from MATLAB/SIMULINK to Real-Time

    NASA Astrophysics Data System (ADS)

    Mikkili, Suresh; Panda, Anup Kumar; Prattipati, Jayanthi

    2014-07-01

    Nowadays the researchers want to develop their model in real-time environment. Simulation tools have been widely used for the design and improvement of electrical systems since the mid twentieth century. The evolution of simulation tools has progressed in step with the evolution of computing technologies. In recent years, computing technologies have improved dramatically in performance and become widely available at a steadily decreasing cost. Consequently, simulation tools have also seen dramatic performance gains and steady cost decreases. Researchers and engineers now have the access to affordable, high performance simulation tools that were previously too cost prohibitive, except for the largest manufacturers. This work has introduced a specific class of digital simulator known as a real-time simulator by answering the questions "what is real-time simulation", "why is it needed" and "how it works". The latest trend in real-time simulation consists of exporting simulation models to FPGA. In this article, the Steps involved for implementation of a model from MATLAB to REAL-TIME are provided in detail.

  14. Real-Time Aircraft Cosmic Ray Radiation Exposure Predictions from the NAIRAS Model

    NASA Astrophysics Data System (ADS)

    Mertens, C. J.; Tobiska, W.; Kress, B. T.; Xu, X.

    2012-12-01

    The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) is a prototype operational model for predicting commercial aircraft radiation exposure from galactic and solar cosmic rays. NAIRAS predictions are currently streaming live from the project's public website, and the exposure rate nowcast is also available on the SpaceWx smartphone app for iPhone, IPad, and Android. Cosmic rays are the primary source of human exposure to high linear energy transfer radiation at aircraft altitudes, which increases the risk of cancer and other adverse health effects. Thus, the NAIRAS model addresses an important national need with broad societal, public health and economic benefits. There is also interest in extending NAIRAS to the LEO environment to address radiation hazard issues for the emerging commercial spaceflight industry. The processes responsible for the variability in the solar wind, interplanetary magnetic field, solar energetic particle spectrum, and the dynamical response of the magnetosphere to these space environment inputs, strongly influence the composition and energy distribution of the atmospheric ionizing radiation field. Real-time observations are required at a variety of locations within the geospace environment. The NAIRAS model is driven by real-time input data from ground-, atmospheric-, and space-based platforms. During the development of the NAIRAS model, new science questions and observational data gaps were identified that must be addressed in order to obtain a more reliable and robust operational model of atmospheric radiation exposure. The focus of this talk is to present the current capabilities of the NAIRAS model, discuss future developments in aviation radiation modeling and instrumentation, and propose strategies and methodologies of bridging known gaps in current modeling and observational capabilities.

  15. A model for real-time quantitative rainfall forecasting using remote sensing. 1. Formulation

    NASA Astrophysics Data System (ADS)

    French, Mark N.; Krajewski, Witold F.

    1994-04-01

    A physically based rainfall forecasting model for real-time hydrologic applications is developed with emphasis on utilization of remote sensing observations. Temporal and spatial scales of interest are lead times of the order of hours and areas of the order of 10 km2. The dynamic model is derived from conservation of mass in a cloud column as defined by the continuity equations for air, liquid water, water vapor, and cloud water. Conservation of momentum is modeled using a semi-Lagrangian frame of reference. The model state is vertically integrated liquid water content in a column of the atmosphere. Additionally, laws of thermodynamics, adiabatic air parcel theory, and cloud microphysics are applied to derive a basic parameterization of the governing equations of model dynamics. The parameterization is in terms of hydrometeorologic observables including radar reflectivity, satellite-infrared brightness temperature, and ground-level air temperature, dew point temperature, and pressure. Implementation and application is described by French et al. (this issue) and involves incorporation of uncertainty analysis and a two-dimensional spatial domain, where the dynamics of the continuous space-time rainfall process are discretized onto a rectangular grid.

  16. Optimizing Real-Time Vaccine Allocation in a Stochastic SIR Model

    PubMed Central

    Nguyen, Chantal; Carlson, Jean M.

    2016-01-01

    Real-time vaccination following an outbreak can effectively mitigate the damage caused by an infectious disease. However, in many cases, available resources are insufficient to vaccinate the entire at-risk population, logistics result in delayed vaccine deployment, and the interaction between members of different cities facilitates a wide spatial spread of infection. Limited vaccine, time delays, and interaction (or coupling) of cities lead to tradeoffs that impact the overall magnitude of the epidemic. These tradeoffs mandate investigation of optimal strategies that minimize the severity of the epidemic by prioritizing allocation of vaccine to specific subpopulations. We use an SIR model to describe the disease dynamics of an epidemic which breaks out in one city and spreads to another. We solve a master equation to determine the resulting probability distribution of the final epidemic size. We then identify tradeoffs between vaccine, time delay, and coupling, and we determine the optimal vaccination protocols resulting from these tradeoffs. PMID:27043931

  17. Defect Dynamics in Artificial Colloidal Ice: Real-Time Observation, Manipulation, and Logic Gate.

    PubMed

    Loehr, Johannes; Ortiz-Ambriz, Antonio; Tierno, Pietro

    2016-10-14

    We study the defect dynamics in a colloidal spin ice system realized by filling a square lattice of topographic double well islands with repulsively interacting magnetic colloids. We focus on the contraction of defects in the ground state, and contraction or expansion in a metastable biased state. Combining real-time experiments with simulations, we prove that these defects behave like emergent topological monopoles obeying a Coulomb law with an additional line tension. We further show how to realize a completely resettable "nor" gate, which provides guidelines for fabrication of nanoscale logic devices based on the motion of topological magnetic monopoles.

  18. Quasi-dynamical analysis and real-time tissue temperature monitoring during laser vaporization

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Ray, Aditi; Jebens, Dave; Chia, Ray; Hasenberg, Tom

    2014-03-01

    Vaporization and coagulation are two fundamental processes that can be performed during laser-tissue ablation. We demonstrated a method allowing quasi-dynamically observing of the cross-sectional images of tissue response during ablation. The results showed that coagulation depth is relatively constant during vaporization, which supports the excellent hemostasis of green laser benign prostate hyperplasia (BPH) treatment. We also verified a new technology for real-time, in situ tissue temperature monitoring, which may be promising for in vivo tissue vaporization degree feedback during laser ablation to improve the vaporization efficiency and avoid complications.

  19. Real-time high-resolution heterodyne-based measurements of spectral dynamics in fibre lasers

    NASA Astrophysics Data System (ADS)

    Sugavanam, Srikanth; Fabbri, Simon; Le, Son Thai; Lobach, Ivan; Kablukov, Sergey; Khorev, Serge; Churkin, Dmitry

    2016-03-01

    Conventional tools for measurement of laser spectra (e.g. optical spectrum analysers) capture data averaged over a considerable time period. However, the generation spectrum of many laser types may involve spectral dynamics whose relatively fast time scale is determined by their cavity round trip period, calling for instrumentation featuring both high temporal and spectral resolution. Such real-time spectral characterisation becomes particularly challenging if the laser pulses are long, or they have continuous or quasi-continuous wave radiation components. Here we combine optical heterodyning with a technique of spatio-temporal intensity measurements that allows the characterisation of such complex sources. Fast, round-trip-resolved spectral dynamics of cavity-based systems in real-time are obtained, with temporal resolution of one cavity round trip and frequency resolution defined by its inverse (85 ns and 24 MHz respectively are demonstrated). We also show how under certain conditions for quasi-continuous wave sources, the spectral resolution could be further increased by a factor of 100 by direct extraction of phase information from the heterodyned dynamics or by using double time scales within the spectrogram approach.

  20. Real-time high-resolution heterodyne-based measurements of spectral dynamics in fibre lasers.

    PubMed

    Sugavanam, Srikanth; Fabbri, Simon; Le, Son Thai; Lobach, Ivan; Kablukov, Sergey; Khorev, Serge; Churkin, Dmitry

    2016-03-17

    Conventional tools for measurement of laser spectra (e.g. optical spectrum analysers) capture data averaged over a considerable time period. However, the generation spectrum of many laser types may involve spectral dynamics whose relatively fast time scale is determined by their cavity round trip period, calling for instrumentation featuring both high temporal and spectral resolution. Such real-time spectral characterisation becomes particularly challenging if the laser pulses are long, or they have continuous or quasi-continuous wave radiation components. Here we combine optical heterodyning with a technique of spatio-temporal intensity measurements that allows the characterisation of such complex sources. Fast, round-trip-resolved spectral dynamics of cavity-based systems in real-time are obtained, with temporal resolution of one cavity round trip and frequency resolution defined by its inverse (85 ns and 24 MHz respectively are demonstrated). We also show how under certain conditions for quasi-continuous wave sources, the spectral resolution could be further increased by a factor of 100 by direct extraction of phase information from the heterodyned dynamics or by using double time scales within the spectrogram approach.

  1. Real-time high-resolution heterodyne-based measurements of spectral dynamics in fibre lasers

    PubMed Central

    Sugavanam, Srikanth; Fabbri, Simon; Le, Son Thai; Lobach, Ivan; Kablukov, Sergey; Khorev, Serge; Churkin, Dmitry

    2016-01-01

    Conventional tools for measurement of laser spectra (e.g. optical spectrum analysers) capture data averaged over a considerable time period. However, the generation spectrum of many laser types may involve spectral dynamics whose relatively fast time scale is determined by their cavity round trip period, calling for instrumentation featuring both high temporal and spectral resolution. Such real-time spectral characterisation becomes particularly challenging if the laser pulses are long, or they have continuous or quasi-continuous wave radiation components. Here we combine optical heterodyning with a technique of spatio-temporal intensity measurements that allows the characterisation of such complex sources. Fast, round-trip-resolved spectral dynamics of cavity-based systems in real-time are obtained, with temporal resolution of one cavity round trip and frequency resolution defined by its inverse (85 ns and 24 MHz respectively are demonstrated). We also show how under certain conditions for quasi-continuous wave sources, the spectral resolution could be further increased by a factor of 100 by direct extraction of phase information from the heterodyned dynamics or by using double time scales within the spectrogram approach. PMID:26984634

  2. Real-time capable first principle based modelling of tokamak turbulent transport

    NASA Astrophysics Data System (ADS)

    Citrin, J.; Breton, S.; Felici, F.; Imbeaux, F.; Aniel, T.; Artaud, J. F.; Baiocchi, B.; Bourdelle, C.; Camenen, Y.; Garcia, J.

    2015-09-01

    A real-time capable core turbulence tokamak transport model is developed. This model is constructed from the regularized nonlinear regression of quasilinear gyrokinetic transport code output. The regression is performed with a multilayer perceptron neural network. The transport code input for the neural network training set consists of five dimensions, and is limited to adiabatic electrons. The neural network model successfully reproduces transport fluxes predicted by the original quasilinear model, while gaining five orders of magnitude in computation time. The model is implemented in a real-time capable tokamak simulator, and simulates a 300 s ITER discharge in 10 s. This proof-of-principle for regression based transport models anticipates a significant widening of input space dimensionality and physics realism for future training sets. This aims to provide unprecedented computational speed coupled with first-principle based physics for real-time control and integrated modelling applications.

  3. Real-Time Probing of Electron Dynamics Using Attosecond Time-Resolved Spectroscopy

    NASA Astrophysics Data System (ADS)

    Ramasesha, Krupa; Leone, Stephen R.; Neumark, Daniel M.

    2016-05-01

    Attosecond science has paved the way for direct probing of electron dynamics in gases and solids. This review provides an overview of recent attosecond measurements, focusing on the wealth of knowledge obtained by the application of isolated attosecond pulses in studying dynamics in gases and solid-state systems. Attosecond photoelectron and photoion measurements in atoms reveal strong-field tunneling ionization and a delay in the photoemission from different electronic states. These measurements applied to molecules have shed light on ultrafast intramolecular charge migration. Similar approaches are used to understand photoemission processes from core and delocalized electronic states in metal surfaces. Attosecond transient absorption spectroscopy is used to follow the real-time motion of valence electrons and to measure the lifetimes of autoionizing channels in atoms. In solids, it provides the first measurements of bulk electron dynamics, revealing important phenomena such as the timescales governing the switching from an insulator to a metallic state and carrier-carrier interactions.

  4. Real-time observation of the conformational dynamics of mitochondrial Hsp70 by spFRET.

    PubMed

    Sikor, Martin; Mapa, Koyeli; von Voithenberg, Lena Voith; Mokranjac, Dejana; Lamb, Don C

    2013-05-29

    The numerous functions of the important class of molecular chaperones, heat shock proteins 70 (Hsp70), rely on cycles of intricate conformational changes driven by ATP-hydrolysis and regulated by cochaperones and substrates. Here, we used Förster resonance energy transfer to study the conformational dynamics of individual molecules of Ssc1, a mitochondrial Hsp70, in real time. The intrinsic dynamics of the substrate-binding domain of Ssc1 was observed to be uncoupled from the dynamic interactions between substrate- and nucleotide-binding domains. Analysis of the fluctuations in the interdomain separation revealed frequent transitions to a nucleotide-free state. The nucleotide-exchange factor Mge1 did not induce ADP release, as expected, but rather facilitated binding of ATP. These results indicate that the conformational cycle of Ssc1 is more elaborate than previously thought and provide insight into how the Hsp70s can perform a wide variety of functions.

  5. Real-time measurements of membrane surface dynamics on macrophages and the phagocytosis of Leishmania parasites.

    PubMed

    Coelho Neto, José; Agero, Ubirajara; Oliveira, Diogo C P; Gazzinelli, Ricardo T; Mesquita, Oscar N

    2005-02-15

    Defocusing microscopy was used for real-time observation and quantification of membrane surface dynamics in murine bone marrow macrophages. Small random membrane fluctuations (SRMF), possibly metabolic driven, were detected uniformly over all membrane surface. Morphological and dynamical parameters of ruffles, such as shape, dimensions, and velocity of propagation, were analyzed. Optical tweezers were used to promote phagocytosis of single Leishmania amazonensis amastigotes by selected macrophages. Analysis of ruffling activity on the macrophages before and during phagocytosis of the parasites indicated that increased ruffling response near forming phagosomes, most likely induced by the parasite, accelerates phagocytosis. The effects of temperature decrease on the dynamics of membrane surface fluctuations and on the phagocytosis of parasites were used to determine the overall activation energies involved in these processes. The values obtained support the existence of strong correlation between membrane motility and phagocytic capacity.

  6. Real time acousto-ultrasonic NDE technique for monitoring damage in ceramic composites under dynamic loads

    NASA Technical Reports Server (NTRS)

    Tiwari, Anil

    1995-01-01

    Research effort was directed towards developing a near real-time, acousto-ultrasonic (AU), nondestructive evaluation (NDE) tool to study the failure mechanisms of ceramic composites. Progression of damage is monitored in real-time by observing the changes in the received AU signal during the actual test. During the real-time AU test, the AU signals are generated and received by the AU transducers attached to the specimen while it is being subjected to increasing quasi-static loads or cyclic loads (10 Hz, R = 1.0). The received AU signals for 64 successive pulses were gated in the time domain (T = 40.96 micro sec) and then averaged every second over ten load cycles and stored in a computer file during fatigue tests. These averaged gated signals are representative of the damage state of the specimen at that point of its fatigue life. This is also the first major attempt in the development and application of real-time AU for continuously monitoring damage accumulation during fatigue without interrupting the test. The present work has verified the capability of the AU technique to assess the damage state in silicon carbide/calcium aluminosilicate (SiC/CAS) and silicon carbide/ magnesium aluminosilicate (SiC/MAS) ceramic composites. Continuous monitoring of damage initiation and progression under quasi-static ramp loading in tension to failure of unidirectional and cross-ply SiC/CAS and quasi-isotropic SiC/MAS ceramic composite specimens at room temperature was accomplished using near real-time AU parameters. The AU technique was shown to be able to detect the stress levels for the onset and saturation of matrix cracks, respectively. The critical cracking stress level is used as a design stress for brittle matrix composites operating at elevated temperatures. The AU technique has found that the critical cracking stress level is 10-15% below the level presently obtained for design purposes from analytical models. An acousto-ultrasonic stress-strain response (AUSSR) model

  7. Design of real-time locomotion generator with map-based neuronal models

    NASA Astrophysics Data System (ADS)

    Rulkov, Nikolai; Ayers, Joseph; Hunt, Mark

    2008-03-01

    We are developing an electronic nervous system for a biomimetic robot based on an established neurobiological model system, the Sea Lamprey. Undulatory locomotion of the lamprey is coordinated by a concatenated network of over 100 segmental central pattern generators (CPGs). To achieve real time operation in a DSP chip, we are using simple phenomenological models of neurons and synapses based on the dynamics of nonlinear maps. CPG networks based on known neuronal circuitry have replicated main properties of the dynamical behavior of the animal model. The results of numerical studies of the neuronal activity coordinating various swimming patterns in the reduced model of the CPG are considered. Both ascending and descending connections between segmental CPGs can mediate both forward and backward propagating flexion waves based on anterior or posterior bias by descending premotor commands. Bilaterally asymmetric biases of descending commands can mediate turning. The CPG outputs control 5 shape memory alloy actuators on each side to generate coordinated undulations. Two dorsal and ventral pitch actuators control the angle between the hull and undulator to control dive and climb. Descending commands are modulated by an analog compass, inclinometers, accelerometers and a short baseline sonar array to mediate homing by the vehicle on a sonar beacon.

  8. A New Model for Real-Time Regional Vertical Total Electron Content and Differential Code Bias Estimation Using IGS Real-Time Service (IGS-RTS) Products

    NASA Astrophysics Data System (ADS)

    Abdelazeem, Mohamed; Çelik, Rahmi N.; El-Rabbany, Ahmed

    2016-04-01

    The international global navigation satellite system (GNSS) real-time service (IGS-RTS) products have been used extensively for real-time precise point positioning and ionosphere modeling applications. In this study, we develop a regional model for real-time vertical total electron content (RT-VTEC) and differential code bias (RT-DCB) estimation over Europe using the IGS-RTS satellite orbit and clock products. The developed model has a spatial and temporal resolution of 1°×1° and 15 minutes, respectively. GPS observations from a regional network consisting of 60 IGS and EUREF reference stations are processed in the zero-difference mode using the Bernese-5.2 software package in order to extract the geometry-free linear combination of the smoothed code observations. The spherical harmonic expansion function is used to model the VTEC, the receiver and the satellite DCBs. To validate the proposed model, the RT-VTEC values are computed and compared with the final IGS-global ionospheric map (IGS-GIM) counterparts in three successive days under high solar activity including one of an extreme geomagnetic activity. The real-time satellite DCBs are also estimated and compared with the IGS-GIM counterparts. Moreover, the real-time receiver DCB for six IGS stations are obtained and compared with the IGS-GIM counterparts. The examined stations are located in different latitudes with different receiver types. The findings reveal that the estimated RT-VTEC values show agreement with the IGS-GIM counterparts with root mean-square-errors (RMSEs) values less than 2 TEC units. In addition, RMSEs of both the satellites and receivers DCBs are less than 0.85 ns and 0.65 ns, respectively in comparison with the IGS-GIM.

  9. A Mixed Model for Real-Time, Interactive Simulation of a Cable Passing Through Several Pulleys

    SciTech Connect

    Garcia-Fernandez, Ignacio; Pla-Castells, Marta; Martinez-Dura, Rafael J.

    2007-09-06

    A model of a cable and pulleys is presented that can be used in Real Time Computer Graphics applications. The model is formulated by the coupling of a damped spring and a variable coefficient wave equation, and can be integrated in more complex mechanical models of lift systems, such as cranes, elevators, etc. with a high degree of interactivity.

  10. Quantum statistics and classical mechanics: real time correlation functions from ring polymer molecular dynamics.

    PubMed

    Craig, Ian R; Manolopoulos, David E

    2004-08-22

    We propose an approximate method for calculating Kubo-transformed real-time correlation functions involving position-dependent operators, based on path integral (Parrinello-Rahman) molecular dynamics. The method gives the exact quantum mechanical correlation function at time zero, exactly satisfies the quantum mechanical detailed balance condition, and for correlation functions of the form C(Ax)(t) and C(xB)(t) it gives the exact result for a harmonic potential. It also works reasonably well at short times for more general potentials and correlation functions, as we illustrate with some example calculations. The method provides a consistent improvement over purely classical molecular dynamics that is most apparent in the low-temperature regime.

  11. Real-time data acquisition system for the NASA Langley transonic dynamics tunnel

    NASA Technical Reports Server (NTRS)

    Cole, P. H.

    1979-01-01

    The hardware configuration of the Transonic Dynamics Wind Tunnel Data Acquisition System (DAS) which consists of an analog front end that can process up to 260 channels of data is presented. The DAS also has a multi-channel analog-to-digital subsystem that can process up to 50,000 samples of data per sec, and a digital computer with standard and nonstandard devices, with graphics capability. The software configuration of the DAS and complex hardware/software interfaces are described, which can provide automatic amplifier gain and offset adjustment for each data channel. Finally, a summary of specific DAS applications is given including the real-time processing of dynamic deflection data, unsteady pressure measurements, and flutter and buffet data.

  12. Real-time identification method of driver model with steering manipulation

    NASA Astrophysics Data System (ADS)

    Tokutake, Hiroshi; Sugimoto, Youichi; Shirakata, Tetsuro

    2013-01-01

    This study proposes a method for real-time identification of a driver model. The proposed method requires only the yaw rate sensor, the steering angle sensor, and velocity sensors that are usually installed in the production car. The identification algorithm involves the division of the recorded data, prefiltering of the divided data, estimation of the driver's desired response, and identification. The prefilter extracts the driver's involuntary response that can be modelled in a simple form. The ideal car response that the driver attempts to track is estimated from the recorded data, and this response is provided to the identification algorithm of the feedback driver model for error tracking. These newly developed methods enable real-time identification under actual driving conditions. The driving simulator experiments and the actual driving tests were performed, and the proposed method was validated. The results show that the time history of the variation in the driver's characteristics can be realised in real time using the proposed method.

  13. Real-time modeling and simulation of distribution feeder and distributed resources

    NASA Astrophysics Data System (ADS)

    Singh, Pawan

    The analysis of the electrical system dates back to the days when analog network analyzers were used. With the advent of digital computers, many programs were written for power-flow and short circuit analysis for the improvement of the electrical system. Real-time computer simulations can answer many what-if scenarios in the existing or the proposed power system. In this thesis, the standard IEEE 13-Node distribution feeder is developed and validated on a real-time platform OPAL-RT. The concept and the challenges of the real-time simulation are studied and addressed. Distributed energy resources include some of the commonly used distributed generation and storage devices like diesel engine, solar photovoltaic array, and battery storage system are modeled and simulated on a real-time platform. A microgrid encompasses a portion of an electric power distribution which is located downstream of the distribution substation. Normally, the microgrid operates in paralleled mode with the grid; however, scheduled or forced isolation can take place. In such conditions, the microgrid must have the ability to operate stably and autonomously. The microgrid can operate in grid connected and islanded mode, both the operating modes are studied in the last chapter. Towards the end, a simple microgrid controller modeled and simulated on the real-time platform is developed for energy management and protection for the microgrid.

  14. A Dynamic Bioinspired Neural Network Based Real-Time Path Planning Method for Autonomous Underwater Vehicles

    PubMed Central

    2017-01-01

    Real-time path planning for autonomous underwater vehicle (AUV) is a very difficult and challenging task. Bioinspired neural network (BINN) has been used to deal with this problem for its many distinct advantages: that is, no learning process is needed and realization is also easy. However, there are some shortcomings when BINN is applied to AUV path planning in a three-dimensional (3D) unknown environment, including complex computing problem when the environment is very large and repeated path problem when the size of obstacles is bigger than the detection range of sensors. To deal with these problems, an improved dynamic BINN is proposed in this paper. In this proposed method, the AUV is regarded as the core of the BINN and the size of the BINN is based on the detection range of sensors. Then the BINN will move with the AUV and the computing could be reduced. A virtual target is proposed in the path planning method to ensure that the AUV can move to the real target effectively and avoid big-size obstacles automatically. Furthermore, a target attractor concept is introduced to improve the computing efficiency of neural activities. Finally, some experiments are conducted under various 3D underwater environments. The experimental results show that the proposed BINN based method can deal with the real-time path planning problem for AUV efficiently. PMID:28255297

  15. A Dynamic Bioinspired Neural Network Based Real-Time Path Planning Method for Autonomous Underwater Vehicles.

    PubMed

    Ni, Jianjun; Wu, Liuying; Shi, Pengfei; Yang, Simon X

    2017-01-01

    Real-time path planning for autonomous underwater vehicle (AUV) is a very difficult and challenging task. Bioinspired neural network (BINN) has been used to deal with this problem for its many distinct advantages: that is, no learning process is needed and realization is also easy. However, there are some shortcomings when BINN is applied to AUV path planning in a three-dimensional (3D) unknown environment, including complex computing problem when the environment is very large and repeated path problem when the size of obstacles is bigger than the detection range of sensors. To deal with these problems, an improved dynamic BINN is proposed in this paper. In this proposed method, the AUV is regarded as the core of the BINN and the size of the BINN is based on the detection range of sensors. Then the BINN will move with the AUV and the computing could be reduced. A virtual target is proposed in the path planning method to ensure that the AUV can move to the real target effectively and avoid big-size obstacles automatically. Furthermore, a target attractor concept is introduced to improve the computing efficiency of neural activities. Finally, some experiments are conducted under various 3D underwater environments. The experimental results show that the proposed BINN based method can deal with the real-time path planning problem for AUV efficiently.

  16. FPGA-based fused smart sensor for real-time plant-transpiration dynamic estimation.

    PubMed

    Millan-Almaraz, Jesus Roberto; de Jesus Romero-Troncoso, Rene; Guevara-Gonzalez, Ramon Gerardo; Contreras-Medina, Luis Miguel; Carrillo-Serrano, Roberto Valentin; Osornio-Rios, Roque Alfredo; Duarte-Galvan, Carlos; Rios-Alcaraz, Miguel Angel; Torres-Pacheco, Irineo

    2010-01-01

    Plant transpiration is considered one of the most important physiological functions because it constitutes the plants evolving adaptation to exchange moisture with a dry atmosphere which can dehydrate or eventually kill the plant. Due to the importance of transpiration, accurate measurement methods are required; therefore, a smart sensor that fuses five primary sensors is proposed which can measure air temperature, leaf temperature, air relative humidity, plant out relative humidity and ambient light. A field programmable gate array based unit is used to perform signal processing algorithms as average decimation and infinite impulse response filters to the primary sensor readings in order to reduce the signal noise and improve its quality. Once the primary sensor readings are filtered, transpiration dynamics such as: transpiration, stomatal conductance, leaf-air-temperature-difference and vapor pressure deficit are calculated in real time by the smart sensor. This permits the user to observe different primary and calculated measurements at the same time and the relationship between these which is very useful in precision agriculture in the detection of abnormal conditions. Finally, transpiration related stress conditions can be detected in real time because of the use of online processing and embedded communications capabilities.

  17. FPGA-based Fused Smart Sensor for Real-Time Plant-Transpiration Dynamic Estimation

    PubMed Central

    Millan-Almaraz, Jesus Roberto; de Jesus Romero-Troncoso, Rene; Guevara-Gonzalez, Ramon Gerardo; Contreras-Medina, Luis Miguel; Carrillo-Serrano, Roberto Valentin; Osornio-Rios, Roque Alfredo; Duarte-Galvan, Carlos; Rios-Alcaraz, Miguel Angel; Torres-Pacheco, Irineo

    2010-01-01

    Plant transpiration is considered one of the most important physiological functions because it constitutes the plants evolving adaptation to exchange moisture with a dry atmosphere which can dehydrate or eventually kill the plant. Due to the importance of transpiration, accurate measurement methods are required; therefore, a smart sensor that fuses five primary sensors is proposed which can measure air temperature, leaf temperature, air relative humidity, plant out relative humidity and ambient light. A field programmable gate array based unit is used to perform signal processing algorithms as average decimation and infinite impulse response filters to the primary sensor readings in order to reduce the signal noise and improve its quality. Once the primary sensor readings are filtered, transpiration dynamics such as: transpiration, stomatal conductance, leaf-air-temperature-difference and vapor pressure deficit are calculated in real time by the smart sensor. This permits the user to observe different primary and calculated measurements at the same time and the relationship between these which is very useful in precision agriculture in the detection of abnormal conditions. Finally, transpiration related stress conditions can be detected in real time because of the use of online processing and embedded communications capabilities. PMID:22163656

  18. Predictable Components of ENSO Evolution in Real-time Multi-Model Predictions

    PubMed Central

    Zheng, Zhihai; Hu, Zeng-Zhen; L’Heureux, Michelle

    2016-01-01

    The most predictable components of the El Niño-Southern Oscillation (ENSO) evolution in real-time multi-model predictions are identified by applying an empirical orthogonal function analysis of the model data that maximizes the signal-to-noise ratio (MSN EOF). The normalized Niño3.4 index is analyzed for nine 3-month overlapping seasons. In this sense, the first most predictable component (MSN EOF1) is the decaying phase of ENSO during the Northern Hemisphere spring, followed by persistence through autumn and winter. The second most predictable component of ENSO evolution, with lower prediction skill and smaller explained variance than MSN EOF1, corresponds to the growth during spring and then persistence in summer and autumn. This result suggests that decay phase of ENSO is more predictable than the growth phase. Also, the most predictable components and the forecast skills in dynamical and statistical models are similar overall, with some differences arising during spring season initial conditions. Finally, the reconstructed predictions, with only the first two MSN components, show higher skill than the model raw predictions. Therefore this method can be used as a diagnostic for model comparison and development, and it can provide a new perspective for the most predictable components of ENSO. PMID:27775016

  19. REAL-TIME MODELING OF MOTOR VEHICLE EMISSIONS FOR ESTIMATING HUMAN EXPOSURES NEAR ROADWAYS

    EPA Science Inventory

    The United States Environmental Protection Agency's (EPA) National Exposure Research Laboratory is developing a real-time model of motor vehicle emissions to improve the methodology for modeling human exposure to motor vehicle emissions. The overall project goal is to develop ...

  20. IR image quality assessment and real-time optimum seeking method based on dynamic visual characteristics

    NASA Astrophysics Data System (ADS)

    Li, Bin; Liu, Gang; Gao, Yongmin; Lei, Hao; Wu, Haiying; Wang, Yu; Rong, Xiaolong

    2016-10-01

    Image quality is an important factor that influences the dynamic target information perception; it is the key factor of real-time target state analysis and judgment. In order to solve the multi-observation station comparison and video optimum seeking problem in the process of target information perception and recognition, an image quality assessment method based on visual characteristics is proposed for infrared target tracking. First, it analyses the basic infrared target image characteristics and application requirements, analyses the status and problems of the multi station optimum seeking technology. According to the expected research results, the processing flow of image processing is established. Then, the image quality objective assessment index is established, which reflects the basic characteristics of the target image, and the assessment index is integrated into the normalized assessment function. According to the quality assessment function, the infrared image quality assessment based on infrared target recognition and image analysis processing is realized, which is mainly characterized by the region of interest and dynamic visual characteristics. And on the basis of this technology, the real-time optimum seeking of multi station infrared target tracking image is completed. In order to verify the effectiveness of the method and the practical application effect, it designs the quality assessment and comparison of different station infrared images. Example shows that the method proposed in this paper can realize multi-observation station infrared image assessment comparison, image quality sorting, the optimum seeking of the infrared image based on the quality assessment. The results accord with the characteristics of infrared target image and dynamic visual characteristics.

  1. Dynamic Chemical and Structural Changes of Heterogeneous Catalysts Observed in Real Time: From Catalysis-Induced Fluxionality to Catalytic Cycles

    DTIC Science & Technology

    2014-11-26

    AFRL-OSR-VA-TR-2014-0321 Dynamic Chemical and Structural Changes of Heterogeneous Catalysts Robert Rioux PENNSYLVANIA STATE UNIVERSITY Final Report...Changes of Heterogeneous Catalysts Observed in Real Time: From Catalysis-Induced Fluxionality to Catalytic Cycles” (FA9550-12-1-0204) Robert M. Rioux...report The results from “Dynamic Chemical and Structural Changes of Heterogeneous Catalysts Observed in Real Time: From Catalysis-Induced

  2. Dynamics of supersonic microparticle impact on elastomers revealed by real-time multi-frame imaging.

    PubMed

    Veysset, David; Hsieh, Alex J; Kooi, Steven; Maznev, Alexei A; Masser, Kevin A; Nelson, Keith A

    2016-05-09

    Understanding high-velocity microparticle impact is essential for many fields, from space exploration to medicine and biology. Investigations of microscale impact have hitherto been limited to post-mortem analysis of impacted specimens, which does not provide direct information on the impact dynamics. Here we report real-time multi-frame imaging studies of the impact of 7 μm diameter glass spheres traveling at 700-900 m/s on elastomer polymers. With a poly(urethane urea) (PUU) sample, we observe a hyperelastic impact phenomenon not seen on the macroscale: a microsphere undergoes a full conformal penetration into the specimen followed by a rebound which leaves the specimen unscathed. The results challenge the established interpretation of the behaviour of elastomers under high-velocity impact.

  3. Real-time quantification of single RNA translation dynamics in living cells.

    PubMed

    Morisaki, Tatsuya; Lyon, Kenneth; DeLuca, Keith F; DeLuca, Jennifer G; English, Brian P; Zhang, Zhengjian; Lavis, Luke D; Grimm, Jonathan B; Viswanathan, Sarada; Looger, Loren L; Lionnet, Timothee; Stasevich, Timothy J

    2016-06-17

    Although messenger RNA (mRNA) translation is a fundamental biological process, it has never been imaged in real time in vivo with single-molecule precision. To achieve this, we developed nascent chain tracking (NCT), a technique that uses multi-epitope tags and antibody-based fluorescent probes to quantify protein synthesis dynamics at the single-mRNA level. NCT reveals an elongation rate of ~10 amino acids per second, with initiation occurring stochastically every ~30 seconds. Polysomes contain ~1 ribosome every 200 to 900 nucleotides and are globular rather than elongated in shape. By developing multicolor probes, we showed that most polysomes act independently; however, a small fraction (~5%) form complexes in which two distinct mRNAs can be translated simultaneously. The sensitivity and versatility of NCT make it a powerful new tool for quantifying mRNA translation kinetics.

  4. Real-time dynamic coupling of GPC-enhanced diffraction-limited focal spots

    NASA Astrophysics Data System (ADS)

    Villangca, Mark; Bañas, Andrew; Kopylov, Oleksii; Palima, Darwin; Glückstad, Jesper

    2015-03-01

    We have previously demonstrated on-demand dynamic coupling of an optically manipulated wave-guided optical waveguide (WOW) using diffractive techniques on a "point and shoot" approach. In this work, the generation of the coupling focal spots is done in real-time following the position of the WOW. Object-tracking routine has been added in the trapping program to get the position of the WOW. This approach allows continuous coupling of light through the WOWs which may be useful in some application. In addition, we include a GPC light shaper module in the holography setup to efficiently illuminate the spatial light modulator (SLM). The ability to switch from on-demand to continuous addressing with efficient illumination leverages our WOWs for potential applications in stimulation and nonlinear optics.

  5. Real-Time Local Range On-Demand and Dynamic Regional Range Images

    SciTech Connect

    Tsap, L.V.

    2000-02-22

    This paper presents a new approach to a gesture tracking system using real-time range on-demand. The system represents a gesture-controlled interface for interactive visual exploration of large data sets. The paper describes a method performing range processing only when necessary and where necessary. Range data is processed only for non-static regions of interest. This is accomplished by a set of filters on the color, motion, and range data. The speedup achieved is between 41% and 54%. The algorithm also includes a robust skin color segmentation insensitive to illumination changes. Selective range processing results in dynamic regional range images (DRRIs). This development is also placed in a broader context of a biological visual system emulation, specifically redundancies and attention mechanisms.

  6. Real-Time Local Range On-Demand for Tracking Gestures and Dynamic Regional Range Images

    SciTech Connect

    Tsap, L.V.

    2000-05-30

    This paper presents a new approach to a gesture-tracking system using real-time range on-demand. The system represents a gesture-controlled interface for interactive visual exploration of large data sets. The paper describes a method performing range processing only when necessary and where necessary. Range data is processed only for non-static regions of interest. This is accomplished by a set of filters on the color, motion, and range data. The speedup achieved is between 41% and 54%. The algorithm also includes a robust skin-color segmentation insensitive to illumination changes. Selective range processing results in dynamic regional range images (DRRIs). This development is also placed in a broader context of a biological visual system emulation, specifically redundancies and attention mechanisms.

  7. Crystallization Dynamics of Organolead Halide Perovskite by Real-Time X-ray Diffraction.

    PubMed

    Miyadera, Tetsuhiko; Shibata, Yosei; Koganezawa, Tomoyuki; Murakami, Takurou N; Sugita, Takeshi; Tanigaki, Nobutaka; Chikamatsu, Masayuki

    2015-08-12

    We analyzed the crystallization process of the CH3NH3PbI3 perovskite by observing real-time X-ray diffraction immediately after combining a PbI2 thin film with a CH3NH3I solution. A detailed analysis of the transformation kinetics demonstrated the fractal diffusion of the CH3NH3I solution into the PbI2 film. Moreover, the perovskite crystal was found to be initially oriented based on the PbI2 crystal orientation but to gradually transition to a random orientation. The fluctuating characteristics of the crystallization process of perovskites, such as fractal penetration and orientational transformation, should be controlled to allow the fabrication of high-quality perovskite crystals. The characteristic reaction dynamics observed in this study should assist in establishing reproducible fabrication processes for perovskite solar cells.

  8. Application of troposphere model from NWP and GNSS data into real-time precise positioning

    NASA Astrophysics Data System (ADS)

    Wilgan, Karina; Hadas, Tomasz; Kazmierski, Kamil; Rohm, Witold; Bosy, Jaroslaw

    2016-04-01

    The tropospheric delay empirical models are usually functions of meteorological parameters (temperature, pressure and humidity). The application of standard atmosphere parameters or global models, such as GPT (global pressure/temperature) model or UNB3 (University of New Brunswick, version 3) model, may not be sufficient, especially for positioning in non-standard weather conditions. The possible solution is to use regional troposphere models based on real-time or near-real time measurements. We implement a regional troposphere model into the PPP (Precise Point Positioning) software GNSS-WARP (Wroclaw Algorithms for Real-time Positioning) developed at Wroclaw University of Environmental and Life Sciences. The software is capable of processing static and kinematic multi-GNSS data in real-time and post-processing mode and takes advantage of final IGS (International GNSS Service) products as well as IGS RTS (Real-Time Service) products. A shortcoming of PPP technique is the time required for the solution to converge. One of the reasons is the high correlation among the estimated parameters: troposphere delay, receiver clock offset and receiver height. To efficiently decorrelate these parameters, a significant change in satellite geometry is required. Alternative solution is to introduce the external high-quality regional troposphere delay model to constrain troposphere estimates. The proposed model consists of zenith total delays (ZTD) and mapping functions calculated from meteorological parameters from Numerical Weather Prediction model WRF (Weather Research and Forecasting) and ZTDs from ground-based GNSS stations using the least-squares collocation software COMEDIE (Collocation of Meteorological Data for Interpretation and Estimation of Tropospheric Pathdelays) developed at ETH Zurich.

  9. Development and implementation of a real-time 30-day readmission predictive model.

    PubMed

    Cronin, Patrick R; Greenwald, Jeffrey L; Crevensten, Gwen C; Chueh, Henry C; Zai, Adrian H

    2014-01-01

    Hospitals are under great pressure to reduce readmissions of patients. Being able to reliably predict patients at increased risk for rehospitalization would allow for tailored interventions to be offered to them. This requires the creation of a functional predictive model specifically designed to support real-time clinical operations. A predictive model for readmissions within 30 days of discharge was developed using retrospective data from 45,924 MGH admissions between 2/1/2012 and 1/31/2013 only including factors that would be available by the day after admission. It was then validated prospectively in a real-time implementation for 3,074 MGH admissions between 10/1/2013 and 10/31/2013. The model developed retrospectively had an AUC of 0.705 with good calibration. The real-time implementation had an AUC of 0.671 although the model was overestimating readmission risk. A moderately discriminative real-time 30-day readmission predictive model can be developed and implemented in a large academic hospital.

  10. Crash Frequency Modeling Using Real-Time Environmental and Traffic Data and Unbalanced Panel Data Models

    PubMed Central

    Chen, Feng; Chen, Suren; Ma, Xiaoxiang

    2016-01-01

    Traffic and environmental conditions (e.g., weather conditions), which frequently change with time, have a significant impact on crash occurrence. Traditional crash frequency models with large temporal scales and aggregated variables are not sufficient to capture the time-varying nature of driving environmental factors, causing significant loss of critical information on crash frequency modeling. This paper aims at developing crash frequency models with refined temporal scales for complex driving environments, with such an effort providing more detailed and accurate crash risk information which can allow for more effective and proactive traffic management and law enforcement intervention. Zero-inflated, negative binomial (ZINB) models with site-specific random effects are developed with unbalanced panel data to analyze hourly crash frequency on highway segments. The real-time driving environment information, including traffic, weather and road surface condition data, sourced primarily from the Road Weather Information System, is incorporated into the models along with site-specific road characteristics. The estimation results of unbalanced panel data ZINB models suggest there are a number of factors influencing crash frequency, including time-varying factors (e.g., visibility and hourly traffic volume) and site-varying factors (e.g., speed limit). The study confirms the unique significance of the real-time weather, road surface condition and traffic data to crash frequency modeling. PMID:27322306

  11. Crash Frequency Modeling Using Real-Time Environmental and Traffic Data and Unbalanced Panel Data Models.

    PubMed

    Chen, Feng; Chen, Suren; Ma, Xiaoxiang

    2016-06-18

    Traffic and environmental conditions (e.g., weather conditions), which frequently change with time, have a significant impact on crash occurrence. Traditional crash frequency models with large temporal scales and aggregated variables are not sufficient to capture the time-varying nature of driving environmental factors, causing significant loss of critical information on crash frequency modeling. This paper aims at developing crash frequency models with refined temporal scales for complex driving environments, with such an effort providing more detailed and accurate crash risk information which can allow for more effective and proactive traffic management and law enforcement intervention. Zero-inflated, negative binomial (ZINB) models with site-specific random effects are developed with unbalanced panel data to analyze hourly crash frequency on highway segments. The real-time driving environment information, including traffic, weather and road surface condition data, sourced primarily from the Road Weather Information System, is incorporated into the models along with site-specific road characteristics. The estimation results of unbalanced panel data ZINB models suggest there are a number of factors influencing crash frequency, including time-varying factors (e.g., visibility and hourly traffic volume) and site-varying factors (e.g., speed limit). The study confirms the unique significance of the real-time weather, road surface condition and traffic data to crash frequency modeling.

  12. Effects of Real-Time NASA Vegetation Data on Model Forecasts of Severe Weather

    NASA Technical Reports Server (NTRS)

    Case, Jonathan L.; Bell, Jordan R.; LaFontaine, Frank J.; Peters-Lidard, Christa D.

    2012-01-01

    The NASA Short-term Prediction Research and Transition (SPoRT) Center has developed a Greenness Vegetation Fraction (GVF) dataset, which is updated daily using swaths of Normalized Difference Vegetation Index data from the Moderate Resolution Imaging Spectroradiometer (MODIS) data aboard the NASA-EOS Aqua and Terra satellites. NASA SPoRT started generating daily real-time GVF composites at 1-km resolution over the Continental United States beginning 1 June 2010. A companion poster presentation (Bell et al.) primarily focuses on impact results in an offline configuration of the Noah land surface model (LSM) for the 2010 warm season, comparing the SPoRT/MODIS GVF dataset to the current operational monthly climatology GVF available within the National Centers for Environmental Prediction (NCEP) and Weather Research and Forecasting (WRF) models. This paper/presentation primarily focuses on individual case studies of severe weather events to determine the impacts and possible improvements by using the real-time, high-resolution SPoRT-MODIS GVFs in place of the coarser-resolution NCEP climatological GVFs in model simulations. The NASA-Unified WRF (NU-WRF) modeling system is employed to conduct the sensitivity simulations of individual events. The NU-WRF is an integrated modeling system based on the Advanced Research WRF dynamical core that is designed to represents aerosol, cloud, precipitation, and land processes at satellite-resolved scales in a coupled simulation environment. For this experiment, the coupling between the NASA Land Information System (LIS) and the WRF model is utilized to measure the impacts of the daily SPoRT/MODIS versus the monthly NCEP climatology GVFs. First, a spin-up run of the LIS is integrated for two years using the Noah LSM to ensure that the land surface fields reach an equilibrium state on the 4-km grid mesh used. Next, the spin-up LIS is run in two separate modes beginning on 1 June 2010, one continuing with the climatology GVFs while the

  13. Real-Time Quantum Dynamics Reveals Complex, Many-Body Interactions in Solvated Nanodroplets.

    PubMed

    Oviedo, M Belén; Wong, Bryan M

    2016-04-12

    Electronic excitations in the liquid phase are surprisingly rich and considerably more complex than either gas-phase or solid-state systems. While the majority of physical and biological processes take place in solvent, our understanding of nonequilibrium excited-state processes in these condensed phase environments remains far from complete. A central and long-standing issue in these solvated environments is the assessment of many-body interactions, particularly when the entire system is out of equilibrium and many quantum states participate in the overall process. Here we present a microscopic picture of solute-solvent electron dynamics and solvatochromic effects, which we uncover using a new real-time quantum dynamics approach for extremely large solvated nanodroplets. In particular, we find that a complex interplay of quantum interactions underlies our observations of solute-solvent effects, and simple macroscopic solvatochromic shifts can even be qualitatively different at the microscopic molecular level in these systems. By treating both the solvent and the solute on the same footing at a quantum-mechanical level, we demonstrate that the electron dynamics in these systems are surprisingly complex, and the emergence of many-body interactions underlies the dynamics in these solvated systems.

  14. Real-time frequency dynamics and high-resolution spectra of a semiconductor laser with delayed feedback

    PubMed Central

    Brunner, Daniel; Porte, Xavier; Soriano, Miguel C.; Fischer, Ingo

    2012-01-01

    The unstable emission of semiconductor lasers due to delayed optical feedback is characterized by combined intensity and frequency dynamics. Nevertheless, real-time experimental investigations have so far been restricted to measurements of intensity dynamics only. Detailed analysis and comparison with numerical models, therefore, have suffered from limited experimental information. Here, we report the simultaneous determination of the lasers optical emission intensity and emission frequency with high temporal resolution. The frequency dynamics is made accessible using a heterodyne detection scheme, in which a beat signal between the delayed feedback laser and a reference laser is generated. Our experiment provides insight into the overall spectral drift on nanosecond timescales, the spectral distribution of the unstable pulsations and the role of the individual external cavity modes. This opens new perspectives for the analysis, understanding and functional utilization of delayed feedback semiconductor lasers. PMID:23066501

  15. Real-time characterization of partially observed epidemics using surrogate models.

    SciTech Connect

    Safta, Cosmin; Ray, Jaideep; Lefantzi, Sophia; Crary, David; Sargsyan, Khachik; Cheng, Karen

    2011-09-01

    We present a statistical method, predicated on the use of surrogate models, for the 'real-time' characterization of partially observed epidemics. Observations consist of counts of symptomatic patients, diagnosed with the disease, that may be available in the early epoch of an ongoing outbreak. Characterization, in this context, refers to estimation of epidemiological parameters that can be used to provide short-term forecasts of the ongoing epidemic, as well as to provide gross information on the dynamics of the etiologic agent in the affected population e.g., the time-dependent infection rate. The characterization problem is formulated as a Bayesian inverse problem, and epidemiological parameters are estimated as distributions using a Markov chain Monte Carlo (MCMC) method, thus quantifying the uncertainty in the estimates. In some cases, the inverse problem can be computationally expensive, primarily due to the epidemic simulator used inside the inversion algorithm. We present a method, based on replacing the epidemiological model with computationally inexpensive surrogates, that can reduce the computational time to minutes, without a significant loss of accuracy. The surrogates are created by projecting the output of an epidemiological model on a set of polynomial chaos bases; thereafter, computations involving the surrogate model reduce to evaluations of a polynomial. We find that the epidemic characterizations obtained with the surrogate models is very close to that obtained with the original model. We also find that the number of projections required to construct a surrogate model is O(10)-O(10{sup 2}) less than the number of samples required by the MCMC to construct a stationary posterior distribution; thus, depending upon the epidemiological models in question, it may be possible to omit the offline creation and caching of surrogate models, prior to their use in an inverse problem. The technique is demonstrated on synthetic data as well as observations from

  16. A potentially robust plasma profile control approach for ITER using real-time estimation of linearized profile response models

    NASA Astrophysics Data System (ADS)

    Kim, S. H.; Lister, J. B.

    2012-07-01

    An active plasma profile control approach for ITER, which is potentially robust by being tolerant to changing and uncertain physics, has been explored in this work, using a technique based on real-time estimation of linearized profile response models. The linearized models approximate static responses of the plasma profiles to power changes in auxiliary heating and current drive systems. These models are updated in real-time, differing from the model-based technique which deduces a dynamic model from identification experiments. The underlying physics is simplified with several assumptions to allow real-time update of the profile response models; however, without significant loss of information necessary for feedback control of the plasma profiles. The response of the electron temperature profile is modelled by simplifying the electron heat transport equation. The response of the safety factor profile is computed by directly relating it to the changes in source current density profiles. The required actuator power changes are directly computed by inverting the response matrix using the singular value decomposition technique. The saturation of the actuator powers is taken into account and the capability of using quantized auxiliary powers is provided. The potential of our active control approach has been tested by applying it to simulations of the ITER hybrid mode operation using CRONOS. In these simulations, either a global transport model or a theory-based local transport model has been used and the electron temperature and safety factor profiles were well controlled either independently or simultaneously.

  17. Real-time dynamic display of registered 4D cardiac MR and ultrasound images using a GPU

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Huang, X.; Eagleson, R.; Guiraudon, G.; Peters, T. M.

    2007-03-01

    In minimally invasive image-guided surgical interventions, different imaging modalities, such as magnetic resonance imaging (MRI), computed tomography (CT), and real-time three-dimensional (3D) ultrasound (US), can provide complementary, multi-spectral image information. Multimodality dynamic image registration is a well-established approach that permits real-time diagnostic information to be enhanced by placing lower-quality real-time images within a high quality anatomical context. For the guidance of cardiac procedures, it would be valuable to register dynamic MRI or CT with intraoperative US. However, in practice, either the high computational cost prohibits such real-time visualization of volumetric multimodal images in a real-world medical environment, or else the resulting image quality is not satisfactory for accurate guidance during the intervention. Modern graphics processing units (GPUs) provide the programmability, parallelism and increased computational precision to begin to address this problem. In this work, we first outline our research on dynamic 3D cardiac MR and US image acquisition, real-time dual-modality registration and US tracking. Then we describe image processing and optimization techniques for 4D (3D + time) cardiac image real-time rendering. We also present our multimodality 4D medical image visualization engine, which directly runs on a GPU in real-time by exploiting the advantages of the graphics hardware. In addition, techniques such as multiple transfer functions for different imaging modalities, dynamic texture binding, advanced texture sampling and multimodality image compositing are employed to facilitate the real-time display and manipulation of the registered dual-modality dynamic 3D MR and US cardiac datasets.

  18. Real-time PCR Machine System Modeling and a Systematic Approach for the Robust Design of a Real-time PCR-on-a-Chip System

    PubMed Central

    Lee, Da-Sheng

    2010-01-01

    Chip-based DNA quantification systems are widespread, and used in many point-of-care applications. However, instruments for such applications may not be maintained or calibrated regularly. Since machine reliability is a key issue for normal operation, this study presents a system model of the real-time Polymerase Chain Reaction (PCR) machine to analyze the instrument design through numerical experiments. Based on model analysis, a systematic approach was developed to lower the variation of DNA quantification and achieve a robust design for a real-time PCR-on-a-chip system. Accelerated lift testing was adopted to evaluate the reliability of the chip prototype. According to the life test plan, this proposed real-time PCR-on-a-chip system was simulated to work continuously for over three years with similar reproducibility in DNA quantification. This not only shows the robustness of the lab-on-a-chip system, but also verifies the effectiveness of our systematic method for achieving a robust design. PMID:22315563

  19. Real-time PCR machine system modeling and a systematic approach for the robust design of a real-time PCR-on-a-chip system.

    PubMed

    Lee, Da-Sheng

    2010-01-01

    Chip-based DNA quantification systems are widespread, and used in many point-of-care applications. However, instruments for such applications may not be maintained or calibrated regularly. Since machine reliability is a key issue for normal operation, this study presents a system model of the real-time Polymerase Chain Reaction (PCR) machine to analyze the instrument design through numerical experiments. Based on model analysis, a systematic approach was developed to lower the variation of DNA quantification and achieve a robust design for a real-time PCR-on-a-chip system. Accelerated lift testing was adopted to evaluate the reliability of the chip prototype. According to the life test plan, this proposed real-time PCR-on-a-chip system was simulated to work continuously for over three years with similar reproducibility in DNA quantification. This not only shows the robustness of the lab-on-a-chip system, but also verifies the effectiveness of our systematic method for achieving a robust design.

  20. Real-Time Monitoring of Photocytotoxicity in Nanoparticles-Based Photodynamic Therapy: A Model-Based Approach

    PubMed Central

    Benachour, Hamanou; Bastogne, Thierry; Toussaint, Magali; Chemli, Yosra; Sève, Aymeric; Frochot, Céline; Lux, François; Tillement, Olivier; Vanderesse, Régis; Barberi-Heyob, Muriel

    2012-01-01

    Nanoparticles are widely suggested as targeted drug-delivery systems. In photodynamic therapy (PDT), the use of multifunctional nanoparticles as photoactivatable drug carriers is a promising approach for improving treatment efficiency and selectivity. However, the conventional cytotoxicity assays are not well adapted to characterize nanoparticles cytotoxic effects and to discriminate early and late cell responses. In this work, we evaluated a real-time label-free cell analysis system as a tool to investigate in vitro cyto- and photocyto-toxicity of nanoparticles-based photosensitizers compared with classical metabolic assays. To do so, we introduced a dynamic approach based on real-time cell impedance monitoring and a mathematical model-based analysis to characterize the measured dynamic cell response. Analysis of real-time cell responses requires indeed new modeling approaches able to describe suited use of dynamic models. In a first step, a multivariate analysis of variance associated with a canonical analysis of the obtained normalized cell index (NCI) values allowed us to identify different relevant time periods following nanoparticles exposure. After light irradiation, we evidenced discriminant profiles of cell index (CI) kinetics in a concentration- and light dose-dependent manner. In a second step, we proposed a full factorial design of experiments associated with a mixed effect kinetic model of the CI time responses. The estimated model parameters led to a new characterization of the dynamic cell responses such as the magnitude and the time constant of the transient phase in response to the photo-induced dynamic effects. These parameters allowed us to characterize totally the in vitro photodynamic response according to nanoparticle-grafted photosensitizer concentration and light dose. They also let us estimate the strength of the synergic photodynamic effect. This dynamic approach based on statistical modeling furnishes new insights for in vitro

  1. A real-time dynamic imaging system for centrifugal microflow platforms

    NASA Astrophysics Data System (ADS)

    Chang, Hsing-Cheng; Tsou, Chingfu; Lai, Chi-Chih; Wun, Guo-Hong

    2008-07-01

    Based on the operational concept of quasi-static state and optoelectronic measurement technology, this research develops a real-time dynamic imaging system for centrifugal microfluidic platforms. Unlike the conventional centrifugal inspection system, which can only be used for examination of the final steady stage in microflow analysis, the developed system with a multi-speed controller and object tracking design is fabricated with low cost to recognize dynamic microflow patterns for different kinds of compact disc-type centrifugal microstructures. The characteristics of rotational control efficiency and image acquisition quality are obtained from fluidic microvalve experiments that are achieved in measuring microflow dynamic responses and in visualizing transient microflow patterns. A man-machine interface was connected with a computer to perform the control and alignment adjustments to catch exact image data for following analysis. The rotation stability of the system has been evaluated, and the rotation speed up to 4500 rpm with vertical vibration less than ±0.2 mm is achieved measured at radial distance of 5 cm. The image acquisition is transferred via USB 2.0 at a speed of up to 30 images per second to the display and memory module.

  2. Real-time characterization of the spatio-temporal dynamics of deformable mirrors

    NASA Astrophysics Data System (ADS)

    Kilpatrick, James; Apostol, Adela; Khizhnya, Anatoliy; Markov, Vladimir; Beresnev, Leonid

    2016-09-01

    Innovative technologies are needed to support and augment the development of various types of deformable mirrors (DM), such as Micro Electro Mechanical Systems (MEMS), segmented, bimorph and membrane types that are currently used in adaptive-optic (AO) systems. The paper discusses the results of initial studies that, could, potentially, be employed for full characterization of the dynamic behavior of adaptive optics mirrors. The experimental data were obtained from a typical bimorph mirror using both, a Shack-Hartman wavefront sensor (SHWFS) and an Imaging Laser Doppler Vibrometer (ILDV) developed exclusively by AS and T Inc. These two sensors were employed for quantitative measurement of both the spatial and temporal dynamics of the DM under broadband excitation via the piezo electric drive elements. The need to characterize the spatial and temporal dynamic response of current and future DM mirror designs is essential for optimizing their performance to a level adequate for high bandwidth AO systems, such as those employed for real-time compensation of wavefront perturbations.

  3. AL and Dst Predictions with the Real-Time WINDMI Model

    NASA Astrophysics Data System (ADS)

    Mays, L.; Horton, W.; Spencer, E.; Weigel, R.; Vassiliadis, D.; Kozyra, J.

    2006-12-01

    First results are presented of the space weather forecasting capability of the real-time WINDMI model that has been operating since February 2006 as a physics based AL and Dst prediction tool. The well documented WINDMI model is a network of eight coupled ordinary differential equations which describe the transfer of power from the solar wind through the geomagnetic tail, the ionosphere, and ring current in the solar WIND driven Magnetosphere-Ionosphere system. WINDMI includes ring current energization physics from substrom injections and outputs a predicted westward auroral electojet index (AL) and equatorial geomagnetic disturbance storm time index (Dst). At the time of abstract submission (August 2006) real-time WINDMI has captured two storms with the first alarm being sent by email for a moderate -150 nT storm on 14-15 April 2006 and a second -100 nT storm on 19-20 August 2006. During the August 2006 storm period the WINDMI model was a more consistent Dst predictor than the Kyoto WDC Quicklook Dst data which has an incorrect offset of ~-100 nT. Real-time WINDMI uses real-time solar wind data from received from ACE every ten minutes to derive in less than one minute of computational time a predicted AL and Dst and magnetopause standoff distance. Real-time WINDMI predicts the AL index one hour earlier than the data is available from the Kyoto WDC Quicklook website and the Dst index two hours earlier. Every ten minutes real-time AL and Dst data and WINDMI predictions are shown on this website: http://orion.ph.utexas.edu/~windmi/realtime/. The 18 physical parameters of WINDMI are approximated analytically from planetary parameters and optimized within physically allowable ranges using the genetic algorithm. Real-time WINDMI parameters are optimized every hour based on 8 hours of past model/data comparison. In addition to the geomagnetic indices the model predicts the major energy components and power transfers in the solar wind-magnetosphere-ionosphere system. The

  4. Real-time inverse hysteresis compensation of piezoelectric actuators with a modified Prandtl-Ishlinskii model.

    PubMed

    Gu, Guo-Ying; Yang, Mei-Ju; Zhu, Li-Min

    2012-06-01

    This paper presents a novel real-time inverse hysteresis compensation method for piezoelectric actuators exhibiting asymmetric hysteresis effect. The proposed method directly utilizes a modified Prandtl-Ishlinskii hysteresis model to characterize the inverse hysteresis effect of piezoelectric actuators. The hysteresis model is then cascaded in the feedforward path for hysteresis cancellation. It avoids the complex and difficult mathematical procedure for constructing an inversion of the hysteresis model. For the purpose of validation, an experimental platform is established. To identify the model parameters, an adaptive particle swarm optimization algorithm is adopted. Based on the identified model parameters, a real-time feedforward controller is implemented for fast hysteresis compensation. Finally, tests are conducted with various kinds of trajectories. The experimental results show that the tracking errors caused by the hysteresis effect are reduced by about 90%, which clearly demonstrates the effectiveness of the proposed inverse compensation method with the modified Prandtl-Ishlinskii model.

  5. Real-Time Onboard Global Nonlinear Aerodynamic Modeling from Flight Data

    NASA Technical Reports Server (NTRS)

    Brandon, Jay M.; Morelli, Eugene A.

    2014-01-01

    Flight test and modeling techniques were developed to accurately identify global nonlinear aerodynamic models onboard an aircraft. The techniques were developed and demonstrated during piloted flight testing of an Aermacchi MB-326M Impala jet aircraft. Advanced piloting techniques and nonlinear modeling techniques based on fuzzy logic and multivariate orthogonal function methods were implemented with efficient onboard calculations and flight operations to achieve real-time maneuver monitoring and analysis, and near-real-time global nonlinear aerodynamic modeling and prediction validation testing in flight. Results demonstrated that global nonlinear aerodynamic models for a large portion of the flight envelope were identified rapidly and accurately using piloted flight test maneuvers during a single flight, with the final identified and validated models available before the aircraft landed.

  6. Functional Fault Modeling Conventions and Practices for Real-Time Fault Isolation

    NASA Technical Reports Server (NTRS)

    Ferrell, Bob; Lewis, Mark; Perotti, Jose; Oostdyk, Rebecca; Brown, Barbara

    2010-01-01

    The purpose of this paper is to present the conventions, best practices, and processes that were established based on the prototype development of a Functional Fault Model (FFM) for a Cryogenic System that would be used for real-time Fault Isolation in a Fault Detection, Isolation, and Recovery (FDIR) system. The FDIR system is envisioned to perform health management functions for both a launch vehicle and the ground systems that support the vehicle during checkout and launch countdown by using a suite of complimentary software tools that alert operators to anomalies and failures in real-time. The FFMs were created offline but would eventually be used by a real-time reasoner to isolate faults in a Cryogenic System. Through their development and review, a set of modeling conventions and best practices were established. The prototype FFM development also provided a pathfinder for future FFM development processes. This paper documents the rationale and considerations for robust FFMs that can easily be transitioned to a real-time operating environment.

  7. Queueing analysis of a canonical model of real-time multiprocessors

    NASA Technical Reports Server (NTRS)

    Krishna, C. M.; Shin, K. G.

    1983-01-01

    A logical classification of multiprocessor structures from the point of view of control applications is presented. A computation of the response time distribution for a canonical model of a real time multiprocessor is presented. The multiprocessor is approximated by a blocking model. Two separate models are derived: one created from the system's point of view, and the other from the point of view of an incoming task.

  8. Real-Time Cognitive Computing Architecture for Data Fusion in a Dynamic Environment

    NASA Technical Reports Server (NTRS)

    Duong, Tuan A.; Duong, Vu A.

    2012-01-01

    A novel cognitive computing architecture is conceptualized for processing multiple channels of multi-modal sensory data streams simultaneously, and fusing the information in real time to generate intelligent reaction sequences. This unique architecture is capable of assimilating parallel data streams that could be analog, digital, synchronous/asynchronous, and could be programmed to act as a knowledge synthesizer and/or an "intelligent perception" processor. In this architecture, the bio-inspired models of visual pathway and olfactory receptor processing are combined as processing components, to achieve the composite function of "searching for a source of food while avoiding the predator." The architecture is particularly suited for scene analysis from visual data and odorant.

  9. Evaluation of the predictability of real-time crash risk models.

    PubMed

    Xu, Chengcheng; Liu, Pan; Wang, Wei

    2016-09-01

    The primary objective of the present study was to investigate the predictability of crash risk models that were developed using high-resolution real-time traffic data. More specifically the present study sought answers to the following questions: (a) how to evaluate the predictability of a real-time crash risk model; and (b) how to improve the predictability of a real-time crash risk model. The predictability is defined as the crash probability given the crash precursor identified by the crash risk model. An equation was derived based on the Bayes' theorem for estimating approximately the predictability of crash risk models. The estimated predictability was then used to quantitatively evaluate the effects of the threshold of crash precursors, the matched and unmatched case-control design, and the control-to-case ratio on the predictability of crash risk models. It was found that: (a) the predictability of a crash risk model can be measured as the product of prior crash probability and the ratio between sensitivity and false alarm rate; (b) there is a trade-off between the predictability and sensitivity of a real-time crash risk model; (c) for a given level of sensitivity, the predictability of the crash risk model that is developed using the unmatched case-controlled sample is always better than that of the model developed using the matched case-controlled sample; and (d) when the control-to-case ratio is beyond 4:1, the increase in control-to-case ratio does not lead to clear improvements in predictability.

  10. Model for Correlating Real-Time Survey Results to Contaminant Concentrations - 12183

    SciTech Connect

    Walker, Stuart A.

    2012-07-01

    The U.S. Environmental Protection Agency (EPA) Superfund program is developing a new Counts Per Minute (CPM) calculator to correlate real-time survey results, which are often expressed as counts per minute, to contaminant concentrations that are more typically provided in risk assessments or for cleanup levels, usually expressed in pCi/g or pCi/m{sup 2}. Currently there is no EPA guidance for Superfund sites on correlating count per minute field survey readings back to risk, dose, or other ARAR based concentrations. The CPM calculator is a web-based model that estimates a gamma detector response for a given level of contamination. The intent of the CPM calculator is to facilitate more real-time measurements within a Superfund response framework. The draft of the CPM calculator is still undergoing internal EPA review. This will be followed by external peer review. It is expected that the CPM calculator will at least be in peer review by the time of WM2012 and possibly finalized at that time. The CPM calculator should facilitate greater use of real-time measurement at Superfund sites. The CPM calculator may also standardize the process of converting lab data to real time measurements. It will thus lessen the amount of lab sampling that is needed for site characterization and confirmation surveys, but it will not remove the need for sampling. (authors)

  11. Extended Time-lapse Intravital Imaging of Real-time Multicellular Dynamics in the Tumor Microenvironment

    PubMed Central

    Harney, Allison S.; Wang, Yarong; Condeelis, John S.; Entenberg, David

    2016-01-01

    In the tumor microenvironment, host stromal cells interact with tumor cells to promote tumor progression, angiogenesis, tumor cell dissemination and metastasis. Multicellular interactions in the tumor microenvironment can lead to transient events including directional tumor cell motility and vascular permeability. Quantification of tumor vascular permeability has frequently used end-point experiments to measure extravasation of vascular dyes. However, due to the transient nature of multicellular interactions and vascular permeability, the kinetics of these dynamic events cannot be discerned. By labeling cells and vasculature with injectable dyes or fluorescent proteins, high-resolution time-lapse intravital microscopy has allowed the direct, real-time visualization of transient events in the tumor microenvironment. Here we describe a method for using multiphoton microscopy to perform extended intravital imaging in live mice to directly visualize multicellular dynamics in the tumor microenvironment. This method details cellular labeling strategies, the surgical preparation of a mammary skin flap, the administration of injectable dyes or proteins by tail vein catheter and the acquisition of time-lapse images. The time-lapse sequences obtained from this method facilitate the visualization and quantitation of the kinetics of cellular events of motility and vascular permeability in the tumor microenvironment. PMID:27341448

  12. Chapter 8: Spatiotemporal dynamics in bacterial cells: real-time studies with single-event resolution.

    PubMed

    Golding, Ido; Cox, Edward C

    2008-01-01

    To produce a quantitative picture of cellular life, one has to study the processes comprising it in individual living cells, quantifying intracellular dynamics with sufficient resolution to describe individual events in space and time. To perform such studies, we have recently developed a novel measurement approach, based on quantitative fluorescence microscopy, and applied it to the study of transcription in Escherichia coli and of the spatiotemporal dynamics of individual mRNA molecules in the cell (Golding and Cox, 2004, 2006a; Golding et al., 2005). The ability to detect individual events in real time depends on the engineering of an endogenous cellular process for amplifying the biological signal, in a way which allows signal detection to be independent of slow and highly stochastic cellular processes (Golding and Cox, 2006a). In this chapter, we describe the ingredients of our system and the way data is acquired and analyzed. We attempt to give general lessons for researchers who wish to implement a similar approach for the study of transcription in other organisms and, more generally, for the study of cellular processes with single-event resolution.

  13. Dynamics formulations for the real-time simulation of constrained motion

    NASA Technical Reports Server (NTRS)

    Kelly, Frederick A.

    1987-01-01

    The Space Shuttle program has relied heavily on simulation throughout all phases of development and operation. Real-time, man-in-the-loop simulation has served the NASA manned space flight program by providing the means to evaluate systems design and integrated systems performance in a simulated flight environment as well as provide a means to train flight crews. New challenges are presented by the development and operation of a permanently manned space station. The assembly of the space station, the transferral of payloads and the use of the space station manipulator to berth the Orbiter are operations critical to the success of the space station. All these operations are examples of constrained motion among the bodies associated with the Orbiter and space station system. The state of the art of formulating the governing dynamical equations of motion for constrained systems are described. The uses of the two basic problems in multibody dynamics are discussed. The most efficient formulations of the equations of motion are addressed from the point of view of completeness. The issues surrounding incorporating the constraints into the equation of motion are presented.

  14. Real time dynamic strain monitoring of optical links using the backreflection of live PSK data.

    PubMed

    Martins, H F; Shi, K; Thomsen, B C; Martin-Lopez, S; Gonzalez-Herraez, M; Savory, S J

    2016-09-19

    A major cause of faults in optical communication links is related to unintentional third party intrusions (normally related to civil/agricultural works) causing fiber breaks or cable damage. These intrusions could be anticipated and avoided by monitoring the dynamic strain recorded along the cable. In this work, a novel technique is proposed to implement real-time distributed strain sensing in parallel with an operating optical communication channel. The technique relies on monitoring the Rayleigh backscattered light from optical communication data transmitted using standard modulation formats. The system is treated as a phase-sensitive OTDR (ΦOTDR) using random and non-periodical non-return-to-zero (NRZ) phase-shift keying (PSK) pulse coding. An I/Q detection unit allows for a full (amplitude, phase and polarization) characterization of the backscattered optical signal, thus achieving a fully linear system in terms of ΦOTDR trace coding/decoding. The technique can be used with different modulation formats, and operation using 4 Gbaud single-polarization dual PSK and 4 Gbaud dual-polarization quadrature PSK is demonstrated. As a proof of concept, distributed sensing of dynamic strain with a sampling of 125 kHz and a spatial resolution of 2.5 cm (set by the bit size) over 500 m is demonstrated for applied sinusoidal strain signals of 500 Hz. The limitations and possibilities for improvement of the technique are also discussed.

  15. Reachability and Real-Time Actuation Strategies for the Active SLIP Model

    DTIC Science & Technology

    2015-06-01

    reachability space of the actuated SLIP model by acti- vating the series elastic actuator at any possible time during the stance phase. Starting from the...University of California Santa Barbara Reachability and Real- Time Actuation Strategies for the Active SLIP Model A dissertation submitted in partial...Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions

  16. A modified elastance model to control mock ventricles in real-time: numerical and experimental validation.

    PubMed

    Colacino, Francesco Maria; Moscato, Francesco; Piedimonte, Fabio; Danieli, Guido; Nicosia, Salvatore; Arabia, Maurizio

    2008-01-01

    This article describes an elastance-based mock ventricle able to reproduce the correct ventricular pressure-volume relationship and its correct interaction with the hydraulic circuit connected to it. A real-time control of the mock ventricle was obtained by a new left ventricular mathematical model including resistive and inductive terms added to the classical Suga-Sagawa elastance model throughout the whole cardiac cycle. A valved piston pump was used to mimic the left ventricle. The pressure measured into the pump chamber was fed back into the mathematical model and the calculated reference left ventricular volume was used to drive the piston. Results show that the classical model is very sensitive to pressure disturbances, especially during the filling phase, while the modified model is able to filter out the oscillations thus eliminating their detrimental effects. The presented model is thus suitable to control mock ventricles in real-time, where sudden pressure disturbances represent a key issue and are not negligible. This real-time controlled mock ventricle is able to reproduce the elastance mechanism of a natural ventricle by mimicking its preload (mean atrial pressure) and afterload (mean aortic pressure) sensitivity, i.e., the Starling law. Therefore, it can be used for designing and testing cardiovascular prostheses due to its capability to reproduce the correct ventricle-vascular system interaction.

  17. A Likelihood Approach for Real-Time Calibration of Stochastic Compartmental Epidemic Models

    PubMed Central

    Zimmer, Christoph; Cohen, Ted

    2017-01-01

    Stochastic transmission dynamic models are especially useful for studying the early emergence of novel pathogens given the importance of chance events when the number of infectious individuals is small. However, methods for parameter estimation and prediction for these types of stochastic models remain limited. In this manuscript, we describe a calibration and prediction framework for stochastic compartmental transmission models of epidemics. The proposed method, Multiple Shooting for Stochastic systems (MSS), applies a linear noise approximation to describe the size of the fluctuations, and uses each new surveillance observation to update the belief about the true epidemic state. Using simulated outbreaks of a novel viral pathogen, we evaluate the accuracy of MSS for real-time parameter estimation and prediction during epidemics. We assume that weekly counts for the number of new diagnosed cases are available and serve as an imperfect proxy of incidence. We show that MSS produces accurate estimates of key epidemic parameters (i.e. mean duration of infectiousness, R0, and Reff) and can provide an accurate estimate of the unobserved number of infectious individuals during the course of an epidemic. MSS also allows for accurate prediction of the number and timing of future hospitalizations and the overall attack rate. We compare the performance of MSS to three state-of-the-art benchmark methods: 1) a likelihood approximation with an assumption of independent Poisson observations; 2) a particle filtering method; and 3) an ensemble Kalman filter method. We find that MSS significantly outperforms each of these three benchmark methods in the majority of epidemic scenarios tested. In summary, MSS is a promising method that may improve on current approaches for calibration and prediction using stochastic models of epidemics. PMID:28095403

  18. A Likelihood Approach for Real-Time Calibration of Stochastic Compartmental Epidemic Models.

    PubMed

    Zimmer, Christoph; Yaesoubi, Reza; Cohen, Ted

    2017-01-01

    Stochastic transmission dynamic models are especially useful for studying the early emergence of novel pathogens given the importance of chance events when the number of infectious individuals is small. However, methods for parameter estimation and prediction for these types of stochastic models remain limited. In this manuscript, we describe a calibration and prediction framework for stochastic compartmental transmission models of epidemics. The proposed method, Multiple Shooting for Stochastic systems (MSS), applies a linear noise approximation to describe the size of the fluctuations, and uses each new surveillance observation to update the belief about the true epidemic state. Using simulated outbreaks of a novel viral pathogen, we evaluate the accuracy of MSS for real-time parameter estimation and prediction during epidemics. We assume that weekly counts for the number of new diagnosed cases are available and serve as an imperfect proxy of incidence. We show that MSS produces accurate estimates of key epidemic parameters (i.e. mean duration of infectiousness, R0, and Reff) and can provide an accurate estimate of the unobserved number of infectious individuals during the course of an epidemic. MSS also allows for accurate prediction of the number and timing of future hospitalizations and the overall attack rate. We compare the performance of MSS to three state-of-the-art benchmark methods: 1) a likelihood approximation with an assumption of independent Poisson observations; 2) a particle filtering method; and 3) an ensemble Kalman filter method. We find that MSS significantly outperforms each of these three benchmark methods in the majority of epidemic scenarios tested. In summary, MSS is a promising method that may improve on current approaches for calibration and prediction using stochastic models of epidemics.

  19. Formal Verification of a Power Controller Using the Real-Time Model Checker UPPAAL

    NASA Technical Reports Server (NTRS)

    Havelund, Klaus; Larsen, Kim Guldstrand; Skou, Arne

    1999-01-01

    A real-time system for power-down control in audio/video components is modeled and verified using the real-time model checker UPPAAL. The system is supposed to reside in an audio/video component and control (read from and write to) links to neighbor audio/video components such as TV, VCR and remote-control. In particular, the system is responsible for the powering up and down of the component in between the arrival of data, and in order to do so in a safe way without loss of data, it is essential that no link interrupts are lost. Hence, a component system is a multitasking system with hard real-time requirements, and we present techniques for modeling time consumption in such a multitasked, prioritized system. The work has been carried out in a collaboration between Aalborg University and the audio/video company B&O. By modeling the system, 3 design errors were identified and corrected, and the following verification confirmed the validity of the design but also revealed the necessity for an upper limit of the interrupt frequency. The resulting design has been implemented and it is going to be incorporated as part of a new product line.

  20. Diagnosis of delay-deadline failures in real time discrete event models.

    PubMed

    Biswas, Santosh; Sarkar, Dipankar; Bhowal, Prodip; Mukhopadhyay, Siddhartha

    2007-10-01

    In this paper a method for fault detection and diagnosis (FDD) of real time systems has been developed. A modeling framework termed as real time discrete event system (RTDES) model is presented and a mechanism for FDD of the same has been developed. The use of RTDES framework for FDD is an extension of the works reported in the discrete event system (DES) literature, which are based on finite state machines (FSM). FDD of RTDES models are suited for real time systems because of their capability of representing timing faults leading to failures in terms of erroneous delays and deadlines, which FSM-based ones cannot address. The concept of measurement restriction of variables is introduced for RTDES and the consequent equivalence of states and indistinguishability of transitions have been characterized. Faults are modeled in terms of an unmeasurable condition variable in the state map. Diagnosability is defined and the procedure of constructing a diagnoser is provided. A checkable property of the diagnoser is shown to be a necessary and sufficient condition for diagnosability. The methodology is illustrated with an example of a hydraulic cylinder.

  1. Heterogeneous Wireless Sensor Network for Real Time Remote Monitoring of Sand Dynamics on Coastal Dunes

    NASA Astrophysics Data System (ADS)

    Pozzebon, Alessandro; Bove, Carmine; Cappelli, Irene; Alquini, Fernanda; Bertoni, Duccio; Sarti, Giovanni

    2016-10-01

    In this paper, the architecture of a heterogeneous Wireless Sensor Network (WSN) to be deployed on coastal sand dunes is described, the aim of which is to provide real time measurements of physical parameters to better define the sediment transport in connection with Aeolian processes. The WSN integrates different typologies of sensors and is provided with both local and remote connection. In particular, three different typologies of sensors are integrated in the network: a multilayer anemometric station, a sensor developed ad-hoc to measure the sand dune level and a sand collector capable of measuring the weight of trapped sand and its quantity. Each sensor node is made up at least of a ZigBee radio module that is able to transmit the data collected by the sensor at a distance of about 100 meters. While the sand level sensor and the sand collector are provided only with this transmission module, the anemometric station also integrates a microprocessor board in charge of data processing. A Gateway node provided with a GSM connection for remote data transmission and a Zigbee radio module for Local Area communication has also been developed. This node is in charge of collecting all the data packets sent by the Sensor Nodes and transmit them to a remote server through GPRS connection. A Web server has been set up to collect these packets and store them in a database. The proposed WSN can provide both a static and a dynamic framework of sand transport processes acting on coastal dunes.

  2. Real-time measurements to characterize dynamics of emulsion interface during simulated intestinal digestion.

    PubMed

    Pan, Yuanjie; Nitin, N

    2016-05-01

    Efficient delivery of bioactives remains a critical challenge due to their limited bioavailability and solubility. While many encapsulation systems are designed to modulate the digestion and release of bioactives within the human gastrointestinal tract, there is limited understanding of how engineered structures influence the delivery of bioactives. The objective of this study was to develop a real-time quantitative method to measure structural changes in emulsion interface during simulated intestinal digestion and to correlate these changes with the release of free fatty acids (FFAs). Fluorescence resonant energy transfer (FRET) was used for rapid in-situ measurement of the structural changes in emulsion interface during simulated intestinal digestion. By using FRET, changes in the intermolecular spacing between the two different fluorescent probes labeled emulsifier were characterized. Changes in FRET measurements were compared with the release of FFAs. The results showed that bile salts and pancreatic lipase interacted immediately with the emulsion droplets and disrupted the emulsion interface as evidenced by reduction in FRET efficacy compared to the control. Similarly, a significant amount of FFAs was released during digestion. Moreover, addition of a second layer of polymers at emulsion interface decreased the extent of interface disruption by bile salts and pancreatic lipase and impacted the amount or rate of FFA release during digestion. These results were consistent with the lower donor/acceptor ratio of the labeled probes from the FRET result. Overall, this study provides a novel approach to analyze the dynamics of emulsion interface during digestion and their relationship with the release of FFAs.

  3. The real-time link between person perception and action: brain potential evidence for dynamic continuity.

    PubMed

    Freeman, Jonathan B; Ambady, Nalini; Midgley, Katherine J; Holcomb, Phillip J

    2011-01-01

    Using event-related potentials, we investigated how the brain extracts information from another's face and translates it into relevant action in real time. In Study 1, participants made between-hand sex categorizations of sex-typical and sex-atypical faces. Sex-atypical faces evoked negativity between 250 and 550 ms (N300/N400 effects), reflecting the integration of accumulating sex-category knowledge into a coherent sex-category interpretation. Additionally, the lateralized readiness potential revealed that the motor cortex began preparing for a correct hand response while social category knowledge was still gradually evolving in parallel. In Study 2, participants made between-hand eye-color categorizations as part of go/no-go trials that were contingent on a target's sex. On no-go trials, although the hand did not actually move, information about eye color partially prepared the motor cortex to move the hand before perception of sex had finalized. Together, these findings demonstrate the dynamic continuity between person perception and action, such that ongoing results from face processing are immediately and continuously cascaded into the motor system over time. The preparation of action begins based on tentative perceptions of another's face before perceivers have finished interpreting what they just saw.

  4. Toward real-time particle tracking using an event-based dynamic vision sensor

    NASA Astrophysics Data System (ADS)

    Drazen, David; Lichtsteiner, Patrick; Häfliger, Philipp; Delbrück, Tobi; Jensen, Atle

    2011-11-01

    Optically based measurements in high Reynolds number fluid flows often require high-speed imaging techniques. These cameras typically record data internally and thus are limited by the amount of onboard memory available. A novel camera technology for use in particle tracking velocimetry is presented in this paper. This technology consists of a dynamic vision sensor in which pixels operate in parallel, transmitting asynchronous events only when relative changes in intensity of approximately 10% are encountered with a temporal resolution of 1 μs. This results in a recording system whose data storage and bandwidth requirements are about 100 times smaller than a typical high-speed image sensor. Post-processing times of data collected from this sensor also increase to about 10 times faster than real time. We present a proof-of-concept study comparing this novel sensor with a high-speed CMOS camera capable of recording up to 2,000 fps at 1,024 × 1,024 pixels. Comparisons are made in the ability of each system to track dense (ρ >1 g/cm3) particles in a solid-liquid two-phase pipe flow. Reynolds numbers based on the bulk velocity and pipe diameter up to 100,000 are investigated.

  5. Topological Casimir effect in a quantum LC circuit: Real-time dynamics

    NASA Astrophysics Data System (ADS)

    Yao, Yuan; Zhitnitsky, Ariel R.

    2017-03-01

    We study novel contributions to the partition function of the Maxwell system defined on a small compact manifold M with nontrivial mappings π1[U (1 )]≅Z . These contributions cannot be described in terms of conventional physical propagating photons with two transverse polarizations and instead emerge as a result of tunneling transitions between topologically different but physically identical vacuum winding states. We argue that if the same system is considered in the background of a small external time-dependent electromagnetic field, then real physical photons will be emitted from the vacuum, similar to the dynamical Casimir effect where photons are radiated from the vacuum due to time-dependent boundary conditions. The fundamental technical difficulty for such an analysis is that the radiation of physical photons on mass shell is inherently a real-time Minkowskian phenomenon while the vacuum fluctuations interpolating between topological |k ⟩ sectors rest upon a Euclidean instanton formulation. We overcome this obstacle by introducing auxiliary topological fields, which allows for a simple analytical continuation between Minkowski and Euclidean descriptions, and develop a quantum mechanical technique to compute these effects. We also propose an experimental realization of such small effects using a microwave cavity with appropriate boundary conditions. Finally, we comment on the possible cosmological implications of this effect.

  6. Real-time tracking of two-electron dynamics in the ionization continuum of Xe

    NASA Astrophysics Data System (ADS)

    Baggash, M.; Rottke, H.

    2015-05-01

    Real-time tracking of atomic two-electron coherent dynamics is investigated through excitation of autoionizing wave packets in the ionization continuum of xenon. Extreme-ultraviolet high-order harmonics of ultrashort Ti:Sapphire laser pulses start the wave packets in energy ranges with a dense covering by two-valence-electron and single-inner-valence-electron excited-state resonances. The 15th harmonic covers resonances of type 5 s 5 p6n l with principle quantum number n ranging from n ≈14 up to n ≈21 and one resonance of type 5 s25 p4n l n'l' with fixed n ,n' and orbital angular momenta l ,l' . In parallel the 17th harmonic starts a wave packet beyond the Xe 5 s 5 p6 ionization threshold where exclusively resonances contribute with two-valence electrons being excited. The evolution in time of these wave packets is probed by inducing a continuum-continuum transition with the Ti:Sapphire laser pulses at variable delay times and detecting the photoelectrons after this two-photon transition. The dependence of the experimental data on the pump-probe delay time can be approximated by a two-photon transition probability derived on the basis of Fano's theory.

  7. The real-time link between person perception and action: Brain potential evidence for dynamic continuity

    PubMed Central

    Freeman, Jonathan B.; Ambady, Nalini; Midgley, Katherine J.; Holcomb, Phillip J.

    2010-01-01

    Using event-related potentials, we investigated how the brain extracts information from another’s face and translates it into relevant action in real-time. In Study 1, participants made between-hand sex categorizations of sex-typical and sex-atypical faces. Sex-atypical faces evoked negativity between 250-550 ms (N300/N400 effects), reflecting the integration of accumulating sex-category knowledge into a coherent sex-category interpretation. Additionally, the lateralized readiness potential (LRP) revealed that the motor cortex began preparing for a correct hand response while social category knowledge was still gradually evolving in parallel. In Study 2, participants made between-hand eye-color categorizations as part of go/no-go trials that were contingent on a target’s sex. On no-go trials, although the hand did not actually move, information about eye color partially prepared the motor cortex to move the hand before perception of sex had finalized. Together, these findings demonstrate the dynamic continuity between person perception and action, such that ongoing results from face processing are immediately and continuously cascaded into the motor system over time. The preparation of action begins based on tentative perceptions of another’s face before perceivers have finished interpreting what they just saw. PMID:20602284

  8. Real-time dynamics of RNA Polymerase II clustering in live human cells

    NASA Astrophysics Data System (ADS)

    Cisse, Ibrahim

    2014-03-01

    Transcription is the first step in the central dogma of molecular biology, when genetic information encoded on DNA is made into messenger RNA. How this fundamental process occurs within living cells (in vivo) is poorly understood,[1] despite extensive biochemical characterizations with isolated biomolecules (in vitro). For high-order organisms, like humans, transcription is reported to be spatially compartmentalized in nuclear foci consisting of clusters of RNA Polymerase II, the enzyme responsible for synthesizing all messenger RNAs. However, little is known of when these foci assemble or their relative stability. We developed an approach based on photo-activation localization microscopy (PALM) combined with a temporal correlation analysis, which we refer to as tcPALM. The tcPALM method enables the real-time characterization of biomolecular spatiotemporal organization, with single-molecule sensitivity, directly in living cells.[2] Using tcPALM, we observed that RNA Polymerase II clusters form transiently, with an average lifetime of 5.1 (+/- 0.4) seconds. Stimuli affecting transcription regulation yielded orders of magnitude changes in the dynamics of the polymerase clusters, implying that clustering is regulated and plays a role in the cells ability to effect rapid response to external signals. Our results suggest that the transient crowding of enzymes may aid in rate-limiting steps of genome regulation.

  9. Vocal tract in female registers--a dynamic real-time MRI study.

    PubMed

    Echternach, Matthias; Sundberg, Johan; Arndt, Susan; Markl, Michael; Schumacher, Martin; Richter, Bernhard

    2010-03-01

    The area of vocal registers is still unclarified. In a previous investigation, dynamic real-time magnetic resonance imaging (MRI), which is able to produce up to 10 frames per second, was successfully applied for examinations of vocal tract modifications in register transitions in male singers. In the present study, the same MRI technique was used to study vocal tract shapes during four professional young sopranos' lower and upper register transitions. The subjects were asked to sing a scale on the vowel /a/ across their transitions. The transitions were acoustically identified by four raters. In neither of these transitions, clear vocal tract changes could be ascertained. However, substantial changes, that is, widening of the lips, opening of the jaw, elevation of the tongue dorsum, and continuous widening of the pharynx, were observed when the singers reached fundamental frequencies that were close to the frequency of the first formant of the vowel sung. These findings suggest that in these subjects register transition was not primarily the result of modifications of the vocal tract.

  10. Real-time modeling of transverse emittance growth due to ground motion

    SciTech Connect

    Shiltsev, V.D.; Parkhomchuk, V.V. |

    1993-09-01

    Ground motion noise at frequencies around 1 kHz causes growth of transverse emittance of the Superconducting Super Collider (SSC) collider beams. The effect was quantitatively investigated using real-time signals from seismometers installed at the tunnel depth and on the surface. The SSC beam was modeled as an ensemble of oscillators with a spread of betatron frequencies. The effect of transverse feedback on emittance growth was investigated.

  11. Real-Time Robust Adaptive Modeling and Scheduling for an Electronic Commerce Server

    NASA Astrophysics Data System (ADS)

    Du, Bing; Ruan, Chun

    With the increasing importance and pervasiveness of Internet services, it is becoming a challenge for the proliferation of electronic commerce services to provide performance guarantees under extreme overload. This paper describes a real-time optimization modeling and scheduling approach for performance guarantee of electronic commerce servers. We show that an electronic commerce server may be simulated as a multi-tank system. A robust adaptive server model is subject to unknown additive load disturbances and uncertain model matching. Overload control techniques are based on adaptive admission control to achieve timing guarantees. We evaluate the performance of the model using a complex simulation that is subjected to varying model parameters and massive overload.

  12. Computational modeling and real-time control of patient-specific laser treatment of cancer.

    PubMed

    Fuentes, D; Oden, J T; Diller, K R; Hazle, J D; Elliott, A; Shetty, A; Stafford, R J

    2009-04-01

    An adaptive feedback control system is presented which employs a computational model of bioheat transfer in living tissue to guide, in real-time, laser treatments of prostate cancer monitored by magnetic resonance thermal imaging. The system is built on what can be referred to as cyberinfrastructure-a complex structure of high-speed network, large-scale parallel computing devices, laser optics, imaging, visualizations, inverse-analysis algorithms, mesh generation, and control systems that guide laser therapy to optimally control the ablation of cancerous tissue. The computational system has been successfully tested on in vivo, canine prostate. Over the course of an 18 min laser-induced thermal therapy performed at M.D. Anderson Cancer Center (MDACC) in Houston, Texas, the computational models were calibrated to intra-operative real-time thermal imaging treatment data and the calibrated models controlled the bioheat transfer to within 5 degrees C of the predetermined treatment plan. The computational arena is in Austin, Texas and managed at the Institute for Computational Engineering and Sciences (ICES). The system is designed to control the bioheat transfer remotely while simultaneously providing real-time remote visualization of the on-going treatment. Post-operative histology of the canine prostate reveal that the damage region was within the targeted 1.2 cm diameter treatment objective.

  13. Parsimonious model development for real-time monitoring of moisture in red meat using hyperspectral imaging.

    PubMed

    Kamruzzaman, Mohammed; Makino, Yoshio; Oshita, Seiichi

    2016-04-01

    A hyperspectral imaging system in the spectral range of 400-1000 nm was investigated to develop a multispectral real-time imaging system allowing the meat industry to determine moisture content in red meat including beef, lamb, and pork. Multivariate calibration models were developed using partial least-squares regression (PLSR) and least-squares support vector machines (LS-SVM) in the full spectral range. Instead of selection of different sets of feature wavelengths for beef, lamb, and pork, a set of 10 feature wavelengths was selected for convenient industrial application for the determination of moisture content in red meat. A quantitative linear function was then established using MLR based on these key feature wavelengths for predicting moisture content of red meat in an online system and creating moisture distribution maps. The results reveal that the combination of hyperspectral imaging and multivariate has great potential in the meat industry for real-time determination of moisture content.

  14. Real Time Optima Tracking Using Harvesting Models of the Genetic Algorithm

    NASA Technical Reports Server (NTRS)

    Baskaran, Subbiah; Noever, D.

    1999-01-01

    Tracking optima in real time propulsion control, particularly for non-stationary optimization problems is a challenging task. Several approaches have been put forward for such a study including the numerical method called the genetic algorithm. In brief, this approach is built upon Darwinian-style competition between numerical alternatives displayed in the form of binary strings, or by analogy to 'pseudogenes'. Breeding of improved solution is an often cited parallel to natural selection in.evolutionary or soft computing. In this report we present our results of applying a novel model of a genetic algorithm for tracking optima in propulsion engineering and in real time control. We specialize the algorithm to mission profiling and planning optimizations, both to select reduced propulsion needs through trajectory planning and to explore time or fuel conservation strategies.

  15. Functional Fault Modeling of a Cryogenic System for Real-Time Fault Detection and Isolation

    NASA Technical Reports Server (NTRS)

    Ferrell, Bob; Lewis, Mark; Oostdyk, Rebecca; Perotti, Jose

    2009-01-01

    When setting out to model and/or simulate a complex mechanical or electrical system, a modeler is faced with a vast array of tools, software, equations, algorithms and techniques that may individually or in concert aid in the development of the model. Mature requirements and a well understood purpose for the model may considerably shrink the field of possible tools and algorithms that will suit the modeling solution. Is the model intended to be used in an offline fashion or in real-time? On what platform does it need to execute? How long will the model be allowed to run before it outputs the desired parameters? What resolution is desired? Do the parameters need to be qualitative or quantitative? Is it more important to capture the physics or the function of the system in the model? Does the model need to produce simulated data? All these questions and more will drive the selection of the appropriate tools and algorithms, but the modeler must be diligent to bear in mind the final application throughout the modeling process to ensure the model meets its requirements without needless iterations of the design. The purpose of this paper is to describe the considerations and techniques used in the process of creating a functional fault model of a liquid hydrogen (LH2) system that will be used in a real-time environment to automatically detect and isolate failures.

  16. Logic Model Checking of Time-Periodic Real-Time Systems

    NASA Technical Reports Server (NTRS)

    Florian, Mihai; Gamble, Ed; Holzmann, Gerard

    2012-01-01

    In this paper we report on the work we performed to extend the logic model checker SPIN with built-in support for the verification of periodic, real-time embedded software systems, as commonly used in aircraft, automobiles, and spacecraft. We first extended the SPIN verification algorithms to model priority based scheduling policies. Next, we added a library to support the modeling of periodic tasks. This library was used in a recent application of the SPIN model checker to verify the engine control software of an automobile, to study the feasibility of software triggers for unintended acceleration events.

  17. Platform for Real-Time Simulation of Dynamic Systems and Hardware-in-the-Loop for Control Algorithms

    PubMed Central

    de Souza, Isaac D. T.; Silva, Sergio N.; Teles, Rafael M.; Fernandes, Marcelo A. C.

    2014-01-01

    The development of new embedded algorithms for automation and control of industrial equipment usually requires the use of real-time testing. However, the equipment required is often expensive, which means that such tests are often not viable. The objective of this work was therefore to develop an embedded platform for the distributed real-time simulation of dynamic systems. This platform, called the Real-Time Simulator for Dynamic Systems (RTSDS), could be applied in both industrial and academic environments. In industrial applications, the RTSDS could be used to optimize embedded control algorithms. In the academic sphere, it could be used to support research into new embedded solutions for automation and control and could also be used as a tool to assist in undergraduate and postgraduate teaching related to the development of projects concerning on-board control systems. PMID:25320906

  18. Platform for real-time simulation of dynamic systems and hardware-in-the-loop for control algorithms.

    PubMed

    de Souza, Isaac D T; Silva, Sergio N; Teles, Rafael M; Fernandes, Marcelo A C

    2014-10-15

    The development of new embedded algorithms for automation and control of industrial equipment usually requires the use of real-time testing. However, the equipment required is often expensive, which means that such tests are often not viable. The objective of this work was therefore to develop an embedded platform for the distributed real-time simulation of dynamic systems. This platform, called the Real-Time Simulator for Dynamic Systems (RTSDS), could be applied in both industrial and academic environments. In industrial applications, the RTSDS could be used to optimize embedded control algorithms. In the academic sphere, it could be used to support research into new embedded solutions for automation and control and could also be used as a tool to assist in undergraduate and postgraduate teaching related to the development of projects concerning on-board control systems.

  19. Real-time dynamics and control strategies for space operations of flexible structures

    NASA Technical Reports Server (NTRS)

    Park, K. C.; Alvin, K. F.; Alexander, S.

    1993-01-01

    This project (NAG9-574) was meant to be a three-year research project. However, due to NASA's reorganizations during 1992, the project was funded only for one year. Accordingly, every effort was made to make the present final report as if the project was meant to be for one-year duration. Originally, during the first year we were planning to accomplish the following: we were to start with a three dimensional flexible manipulator beam with articulated joints and with a linear control-based controller applied at the joints; using this simple example, we were to design the software systems requirements for real-time processing, introduce the streamlining of various computational algorithms, perform the necessary reorganization of the partitioned simulation procedures, and assess the potential speed-up realization of the solution process by parallel computations. The three reports included as part of the final report address: the streamlining of various computational algorithms; the necessary reorganization of the partitioned simulation procedures, in particular the observer models; and an initial attempt of reconfiguring the flexible space structures.

  20. [Research progress on real-time deformable models of soft tissues for surgery simulation].

    PubMed

    Xu, Shaoping; Liu, Xiaoping; Zhang, Hua; Luo, Jie

    2010-04-01

    Biological tissues generally exhibit nonlinearity, anisotropy, quasi-incompressibility and viscoelasticity about material properties. Simulating the behaviour of elastic objects in real time is one of the current objectives of virtual surgery simulation which is still a challenge for researchers to accurately depict the behaviour of human tissues. In this paper, we present a classification of the different deformable models that have been developed. We present the advantages and disadvantages of each one. Finally, we make a comparison of deformable models and perform an evaluation of the state of the art and the future of deformable models.

  1. Unattended real-time re-establishment of visibility in high dynamic range video and stills

    NASA Astrophysics Data System (ADS)

    Abidi, B.

    2014-05-01

    We describe a portable unattended persistent surveillance system that corrects for harsh illumination conditions, where bright sun light creates mixed contrast effects, i.e., heavy shadows and washouts. These effects result in high dynamic range scenes, where illuminance can vary from few luxes to a 6 figure value. When using regular monitors and cameras, such wide span of illuminations can only be visualized if the actual range of values is compressed, leading to the creation of saturated and/or dark noisy areas and a loss of information in these areas. Images containing extreme mixed contrast cannot be fully enhanced from a single exposure, simply because all information is not present in the original data. The active intervention in the acquisition process is required. A software package, capable of integrating multiple types of COTS and custom cameras, ranging from Unmanned Aerial Systems (UAS) data links to digital single-lens reflex cameras (DSLR), is described. Hardware and software are integrated via a novel smart data acquisition algorithm, which communicates to the camera the parameters that would maximize information content in the final processed scene. A fusion mechanism is then applied to the smartly acquired data, resulting in an enhanced scene where information in both dark and bright areas is revealed. Multi-threading and parallel processing are exploited to produce automatic real time full motion corrected video. A novel enhancement algorithm was also devised to process data from legacy and non-controllable cameras. The software accepts and processes pre-recorded sequences and stills, enhances visible, night vision, and Infrared data, and successfully applies to night time and dark scenes. Various user options are available, integrating custom functionalities of the application into intuitive and easy to use graphical interfaces. The ensuing increase in visibility in surveillance video and intelligence imagery will expand the performance and

  2. Quantitative detection of Vibrio cholera toxin by real-time and dynamic cytotoxicity monitoring.

    PubMed

    Jin, Dazhi; Luo, Yun; Zheng, Min; Li, Haijing; Zhang, Jing; Stampfl, Melinda; Xu, Xiao; Ding, Gangqiang; Zhang, Yanjun; Tang, Yi-Wei

    2013-12-01

    We report here the quantitative detection of Vibrio cholerae toxin (CT) in isolates and stool specimens by dynamic monitoring of the full course of CT-mediated cytotoxicity in a real-time cell analysis (RTCA) system. Four cell lines, including Y-1 mouse adrenal tumor cells, Chinese hamster ovary (CHO) cells, small intestine epithelial (FHs74Int) cells, and mouse adrenal gland (PC12-Adh) cells, were evaluated for their suitability for CT-induced cytotoxicity testing. Among them, the Y-1 line was demonstrated to be the most sensitive for CT-mediated cytotoxicity, with limits of detection of 7.0 pg/ml for purified CT and 0.11 ng/ml for spiked CT in pooled negative stool specimens. No CT-mediated cytotoxicity was observed for nontoxigenic V. cholerae, non-V. cholerae species, or non-V. cholerae enterotoxins. The CT-RTCA assay was further validated with 100 stool specimens consecutively collected from patients with diarrhea and 200 V. cholerae isolates recovered from patients and the environment, in comparison to a reference using three detection methods. The CT-RTCA assay had sensitivities and specificities of 97.5% and 100.0%, respectively, for V. cholerae isolates and 90.0% and 97.2% for stool specimens. For stool specimens spiked with CT concentrations ranging from 3.5 pg/ml to 1.8 ng/ml, the inoculation-to-detection time was 1.12 ± 0.38 h, and the values were inversely correlated with CT concentrations (ρ = -1; P = 0.01). The results indicate that the CT-RTCA assay with the Y-1 cell line provides a rapid and sensitive tool for the quantitative detection of CT activities in clinical specimens.

  3. The Real-Time Dynamic Monitoring of microRNA Function in Cholangiocarcinoma

    PubMed Central

    Guo, Zihao; Sun, Xiaoxin; Zhang, Jie

    2014-01-01

    Background Although many studies have confirmed a relationship between microRNAs (miRNAs) and cholangiocarcinoma (CCA), the real-time dynamics of miRNA function have not been examined. Methods miRNA reporter constructs were generated using a recombinant adeno-associated virus vector, which contained complementary sequences for six miRNAs (miR-200a, miR-200b, miR-21, miR-146a, miR-155, and miR-221), along with two independent expression cassettes encoding the fluorescent reporter genes Fluc and Gluc. The spatio-temporal function of each miRNA was monitored both in CCA and control tissues. Results All miRNAs participated in CCA development, with distinct patterns of expression over time. The activity of miR-21 was significantly lower in female T3N0M0 CCA tissue relative to controls at three time points, yet was higher in two male T3N1M0 CCA tissues. The difference in miR-200b function between two male T3N1M0 CCA tissues and their corresponding controls peaked at 24 h, while function in a female T3N0M0 CCA was detected only at 72 h. The four remaining miRNAs (miR-200a, miR146a, miR-155, and miR-221) displayed patient-specific activity patterns in both CCA and control tissues. Conclusion Significant variability was observed in the temporal function of all six miRNAs, which may play an important role in the development of CCA. PMID:24918778

  4. OneRTM: an online real-time modelling platform for the next generation of numerical environmental modelling

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Kingdon, Andrew

    2014-05-01

    Numerical modelling has been applied in many fields to better understand and predict the behaviours of different processes. In our increasingly dynamic world there is an imperative to identify potential stresses and threats in the environment and to respond quickly with sound decisions. However, the limitations in traditional modelling methodologies make it difficult to respond quickly to rapidly developing environmental events, such as floods, droughts and pollution incidents. For example, it is both time consuming and costly to keep model data up-to-date and also to disseminate models results and modelled output datasets to end-users. Crucially it is difficult for people who has limited numerical modelling skills to understand and interact with models and modelled results. In response to these challenges, a proof-of-concept online real-time modelling platform (OneRTM) has been developed as a mechanism for maintaining and disseminating numerical models and datasets. This automatically keeps models current for the most recent input data, links models based on data flow; it makes models and modelled datasets (historic, real-time and forecasted) immediately available via the internet as easy-to-understand dynamic GIS layers and graphs; and it provides online modelling functions to allow non-modellers to manipulate model including running pre-defined scenarios with a few mouse clicks. OneRTM has been successfully applied and tested in the Chalk groundwater flow modelling in the Thames Basin, UK. The system hosts and links groundwater recharge and groundwater flow models in the case study area, and automatically publishes the latest groundwater level layers on the internet once the current weather datasets becomes available. It also provides online functions of generating groundwater hydrograph and running groundwater abstraction scenarios. Although OneRTM is currently tested using groundwater flow modelling as an example, it could be further developed into a platform

  5. Real-time ECG emulation: a multiple dipole model for electrocardiography simulation.

    PubMed

    Abkai, Ciamak; Hesser, Jürgen

    2009-01-01

    A new model for describing electrocardiography (ECG) is presented, which is based on multiple dipoles compared to standard single dipole approaches in vector electrocardiography. The multiple dipole parameters are derived from real data (e.g. four dipoles from 12-channel ECG) by solving the backward problem of ECG numerically. Results are transformed to a waveform description based on Gaussian mixture for every dimension of each dipole. These compact parameterized descriptors are used for a very realistic real-time simulation applying the forward solution of the proposed model.

  6. Interdyad Differences in Early Mother-Infant Face-to-Face Communication: Real-Time Dynamics and Developmental Pathways

    ERIC Educational Resources Information Center

    Lavelli, Manuela; Fogel, Alan

    2013-01-01

    A microgenetic research design with a multiple case study method and a combination of quantitative and qualitative analyses was used to investigate interdyad differences in real-time dynamics and developmental change processes in mother-infant face-to-face communication over the first 3 months of life. Weekly observations of 24 mother-infant dyads…

  7. The Ionosphere Real-Time Assimilative Model, IRTAM - A Status Report

    NASA Astrophysics Data System (ADS)

    Reinisch, Bodo; Galkin, Ivan; Huang, Xueqin; Vesnin, Artem; Bilitza, Dieter

    2014-05-01

    Ionospheric models are generally unable to correctly predict the effects of space weather events on the ionosphere. Taking advantage of today's real-time availability of measured electron density profiles of the bottomside ionosphere, we have developed a technique "IRTAM" to specify real-time foF2 and hmF2 global maps. The measured data arrive at the Lowell GIRO Data Center (LGDC) from some ~70 ionosonde stations of the Global Ionosphere Radio Observatory (GIRO) [Reinisch and Galkin, 2011], usually at a 15 min cadence, and are ingested in LGDC's databases (http://ulcar.uml.edu/DIDBase/). We use the International Reference Ionosphere (IRI) electron density model [Bilitza et al., 2011] as the background model. It is an empirical monthly median model that critically depends on the correct values of the F2 layer peak height hmF2 and density NmF2 (or critical frequency foF2). The IRI model uses the so-called CCIR (or URSI) coefficients for the specification of the median foF2 and hmF2 maps. IRTAM assimilates the measured GIRO data in IRI by "adjusting" the CCIR coefficients on-the-fly. The updated maps of foF2 and hmF2 for the last 24 hours before now-time are continuously displayed on http://giro.uml.edu/RTAM [Galkin et al., 2012]. The "adjusted" bottomside profiles can be extended to the topside by using the new Vary-Chap topside profile model [Nsumei et al., 2012] which extends the profile from hmF2 to the plasmasphere. References Bilitza D., L.-A. McKinnell, B. Reinisch, and T. Fuller-Rowell (2011), The International Reference Ionosphere (IRI) today and in the future, J. Geodesy, 85:909-920, DOI 10.1007/s00190-010-0427-x Galkin, I. A., B. W. Reinisch, X. Huang, and D. Bilitza (2012), Assimilation of GIRO Data into a Real-Time IRI, Radio Sci., 47, RS0L07, doi:10.1029/2011RS004952. Nsumei, P., B. W. Reinisch, X. Huang, and D. Bilitza (2012), New Vary-Chap profile of the topside ionosphere electron density distribution for use with the IRI Model and the GIRO real time

  8. A model-based, multichannel, real-time capable sawtooth crash detector

    NASA Astrophysics Data System (ADS)

    van den Brand, H.; de Baar, M. R.; van Berkel, M.; Blanken, T. C.; Felici, F.; Westerhof, E.; Willensdorfer, M.; The ASDEX Upgrade Team; The EUROfusion MST1 Team

    2016-07-01

    Control of the time between sawtooth crashes, necessary for ITER and DEMO, requires real-time detection of the moment of the sawtooth crash. In this paper, estimation of sawtooth crash times is demonstrated using the model-based interacting multiple model (IMM) estimator, based on simplified models for the sawtooth crash. In contrast to previous detectors, this detector uses the spatial extent of the sawtooth crash as detection characteristic. The IMM estimator is tuned and applied to multiple ECE channels at once. A model for the sawtooth crash is introduced, which is used in the IMM algorithm. The IMM algorithm is applied to seven datasets from the ASDEX Upgrade tokamak. Five crash models with different mixing radii are used. All sawtooth crashes that have been identified beforehand by visual inspection of the data, are detected by the algorithm. A few additional detections are made, which upon closer inspection are seen to be sawtooth crashes, which show a partial reconnection. A closer inspection of the detected normal crashes shows that about 42% are not well fitted by any of the full reconnection models and show some characteristics of a partial reconnection. In some case, the measurement time is during the sawtooth crashes, which also results in an incorrect estimate of the mixing radius. For data provided at a sampling rate of 1 kHz, the run time of the IMM estimator is below 1 ms, thereby fulfilling real-time requirements.

  9. Real-time nonlinear feedback control of pattern formation in (bio)chemical reaction-diffusion processes: a model study.

    PubMed

    Brandt-Pollmann, U; Lebiedz, D; Diehl, M; Sager, S; Schlöder, J

    2005-09-01

    Theoretical and experimental studies related to manipulation of pattern formation in self-organizing reaction-diffusion processes by appropriate control stimuli become increasingly important both in chemical engineering and cellular biochemistry. In a model study, we demonstrate here exemplarily the application of an efficient nonlinear model predictive control (NMPC) algorithm to real-time optimal feedback control of pattern formation in a bacterial chemotaxis system modeled by nonlinear partial differential equations. The corresponding drift-diffusion model type is representative for many (bio)chemical systems involving nonlinear reaction dynamics and nonlinear diffusion. We show how the computed optimal feedback control strategy exploits the system inherent physical property of wave propagation to achieve desired control aims. We discuss various applications of our approach to optimal control of spatiotemporal dynamics.

  10. Real-time nonlinear feedback control of pattern formation in (bio)chemical reaction-diffusion processes: A model study

    NASA Astrophysics Data System (ADS)

    Brandt-Pollmann, U.; Lebiedz, D.; Diehl, M.; Sager, S.; Schlöder, J.

    2005-09-01

    Theoretical and experimental studies related to manipulation of pattern formation in self-organizing reaction-diffusion processes by appropriate control stimuli become increasingly important both in chemical engineering and cellular biochemistry. In a model study, we demonstrate here exemplarily the application of an efficient nonlinear model predictive control (NMPC) algorithm to real-time optimal feedback control of pattern formation in a bacterial chemotaxis system modeled by nonlinear partial differential equations. The corresponding drift-diffusion model type is representative for many (bio)chemical systems involving nonlinear reaction dynamics and nonlinear diffusion. We show how the computed optimal feedback control strategy exploits the system inherent physical property of wave propagation to achieve desired control aims. We discuss various applications of our approach to optimal control of spatiotemporal dynamics.

  11. A robust approach to battery fuel gauging, part I: Real time model identification

    NASA Astrophysics Data System (ADS)

    Balasingam, B.; Avvari, G. V.; Pattipati, B.; Pattipati, K. R.; Bar-Shalom, Y.

    2014-12-01

    In this paper, the first of a series of papers on battery fuel gauge (BFG), we present a real time parameter estimation strategy for robust state of charge (SOC) tracking. The proposed parameter estimation scheme has the following novel features: it models hysteresis as an error in the open circuit voltage (OCV) and employs a combination of real time, linear parameter estimation and SOC tracking technique to compensate for it. This obviates the need for modeling of hysteresis as a function of SOC and load current. We identify the presence of correlated noise that has been so far ignored in the literature and use it to enhance the accuracy of model identification. As a departure from the conventional "one model fits all" strategy, we identify four different equivalent models of the battery that represent four modes of typical battery operation and develop the framework for seamless SOC tracking by switching. The proposed parameter approach enables a robust initialization/re-initialization strategy for continuous operation of the BFG. The performance of the online parameter estimation scheme was first evaluated through simulated data. Then, the proposed algorithm was validated using hardware-in-the-loop (HIL) data collected from commercially available Li-ion batteries.

  12. Real-time simulation of a spiking neural network model of the basal ganglia circuitry using general purpose computing on graphics processing units.

    PubMed

    Igarashi, Jun; Shouno, Osamu; Fukai, Tomoki; Tsujino, Hiroshi

    2011-11-01

    Real-time simulation of a biologically realistic spiking neural network is necessary for evaluation of its capacity to interact with real environments. However, the real-time simulation of such a neural network is difficult due to its high computational costs that arise from two factors: (1) vast network size and (2) the complicated dynamics of biologically realistic neurons. In order to address these problems, mainly the latter, we chose to use general purpose computing on graphics processing units (GPGPUs) for simulation of such a neural network, taking advantage of the powerful computational capability of a graphics processing unit (GPU). As a target for real-time simulation, we used a model of the basal ganglia that has been developed according to electrophysiological and anatomical knowledge. The model consists of heterogeneous populations of 370 spiking model neurons, including computationally heavy conductance-based models, connected by 11,002 synapses. Simulation of the model has not yet been performed in real-time using a general computing server. By parallelization of the model on the NVIDIA Geforce GTX 280 GPU in data-parallel and task-parallel fashion, faster-than-real-time simulation was robustly realized with only one-third of the GPU's total computational resources. Furthermore, we used the GPU's full computational resources to perform faster-than-real-time simulation of three instances of the basal ganglia model; these instances consisted of 1100 neurons and 33,006 synapses and were synchronized at each calculation step. Finally, we developed software for simultaneous visualization of faster-than-real-time simulation output. These results suggest the potential power of GPGPU techniques in real-time simulation of realistic neural networks.

  13. Real-time modeling of primitive environments through wavelet sensors and Hebbian learning

    NASA Astrophysics Data System (ADS)

    Vaccaro, James M.; Yaworsky, Paul S.

    1999-06-01

    Modeling the world through sensory input necessarily provides a unique perspective for the observer. Given a limited perspective, objects and events cannot always be encoded precisely but must involve crude, quick approximations to deal with sensory information in a real- time manner. As an example, when avoiding an oncoming car, a pedestrian needs to identify the fact that a car is approaching before ascertaining the model or color of the vehicle. In our methodology, we use wavelet-based sensors with self-organized learning to encode basic sensory information in real-time. The wavelet-based sensors provide necessary transformations while a rank-based Hebbian learning scheme encodes a self-organized environment through translation, scale and orientation invariant sensors. Such a self-organized environment is made possible by combining wavelet sets which are orthonormal, log-scale with linear orientation and have automatically generated membership functions. In earlier work we used Gabor wavelet filters, rank-based Hebbian learning and an exponential modulation function to encode textural information from images. Many different types of modulation are possible, but based on biological findings the exponential modulation function provided a good approximation of first spike coding of `integrate and fire' neurons. These types of Hebbian encoding schemes (e.g., exponential modulation, etc.) are useful for quick response and learning, provide several advantages over contemporary neural network learning approaches, and have been found to quantize data nonlinearly. By combining wavelets with Hebbian learning we can provide a real-time front-end for modeling an intelligent process, such as the autonomous control of agents in a simulated environment.

  14. PIV measurements in a real time controlled model wind turbine wake simulator

    NASA Astrophysics Data System (ADS)

    Castillo, R.; Wang, Y.; Monk, T.; Vasquez, S.; Pol, S.; Ren, B.; Swift, A.; Hussain, F.; Westergaard, C. H.

    2016-09-01

    A wind tunnel based “Hyper Accelerated Wind Farm Kinematic-Control Simulator” (HAWKS) is being built at Texas Tech University (TTU) to emulate controlled wind turbine flow physics. The HAWKS model turbine has pitch, yaw and speed controls that could be operated in real time with different power coefficient (Cp) conditions. The purpose of HAWKS is to simulate control strategies, operating at much faster turnaround times. Currently, the fundamental building blocks of the simulator are being tested. A few salient tests results are presented here.

  15. Tailored motivational message generation: A model and practical framework for real-time physical activity coaching.

    PubMed

    Op den Akker, Harm; Cabrita, Miriam; Op den Akker, Rieks; Jones, Valerie M; Hermens, Hermie J

    2015-06-01

    This paper presents a comprehensive and practical framework for automatic generation of real-time tailored messages in behavior change applications. Basic aspects of motivational messages are time, intention, content and presentation. Tailoring of messages to the individual user may involve all aspects of communication. A linear modular system is presented for generating such messages. It is explained how properties of user and context are taken into account in each of the modules of the system and how they affect the linguistic presentation of the generated messages. The model of motivational messages presented is based on an analysis of existing literature as well as the analysis of a corpus of motivational messages used in previous studies. The model extends existing 'ontology-based' approaches to message generation for real-time coaching systems found in the literature. Practical examples are given on how simple tailoring rules can be implemented throughout the various stages of the framework. Such examples can guide further research by clarifying what it means to use e.g. user targeting to tailor a message. As primary example we look at the issue of promoting daily physical activity. Future work is pointed out in applying the present model and framework, defining efficient ways of evaluating individual tailoring components, and improving effectiveness through the creation of accurate and complete user- and context models.

  16. Computer considerations for real time simulation of a generalized rotor model

    NASA Technical Reports Server (NTRS)

    Howe, R. M.; Fogarty, L. E.

    1977-01-01

    Scaled equations were developed to meet requirements for real time computer simulation of the rotor system research aircraft. These equations form the basis for consideration of both digital and hybrid mechanization for real time simulation. For all digital simulation estimates of the required speed in terms of equivalent operations per second are developed based on the complexity of the equations and the required intergration frame rates. For both conventional hybrid simulation and hybrid simulation using time-shared analog elements the amount of required equipment is estimated along with a consideration of the dynamic errors. Conventional hybrid mechanization using analog simulation of those rotor equations which involve rotor-spin frequencies (this consititutes the bulk of the equations) requires too much analog equipment. Hybrid simulation using time-sharing techniques for the analog elements appears possible with a reasonable amount of analog equipment. All-digital simulation with affordable general-purpose computers is not possible because of speed limitations, but specially configured digital computers do have the required speed and consitute the recommended approach.

  17. Real Time Filtering and Parameter Estimation for Dynamical Systems With Many Degrees of Freedom

    DTIC Science & Technology

    2009-08-05

    Forms for Reduced Stochastic Climate Models," PNAS, March 2009, Vol. 16, no. 10, pp. 3649-3653 (with R. Abramov ,) "New Algorithms for Low Frequency...Equatorial Shallow-Water Dynamics," CPAM, Vol. LXI, March 2008, pp. 0002 - 0012 (with R. Abramov ,) "New Approximations and Tests of Linear Fluctuation...Response for Chaotic Nonlinear Forced-Dissipative Dynamical Systems," J. Nonlinear Sci., Vol 18, pp. 303-341,2008 (with R. Abramov ,) "Blended Response

  18. Communication: Constant uncertainty molecular dynamics: A simple and efficient algorithm to incorporate quantum nature into a real-time molecular dynamics simulation.

    PubMed

    Hasegawa, Taisuke

    2016-11-07

    We propose a novel molecular dynamics (MD) algorithm for approximately dealing with a nuclear quantum dynamics in a real-time MD simulation. We have found that real-time dynamics of the ensemble of classical particles acquires quantum nature by introducing a constant quantum mechanical uncertainty constraint on its classical dynamics. The constant uncertainty constraint is handled by the Lagrange multiplier method and implemented into a conventional MD algorithm. The resulting constant uncertainty molecular dynamics (CUMD) is applied to the calculation of quantum position autocorrelation functions on quartic and Morse potentials. The test calculations show that CUMD gives better performance than ring-polymer MD because of the inclusion of the quantum zero-point energy during real-time evolution as well as the quantum imaginary-time statistical effect stored in an initial condition. The CUMD approach will be a possible starting point for new real-time quantum dynamics simulation in condensed phase.

  19. Communication: Constant uncertainty molecular dynamics: A simple and efficient algorithm to incorporate quantum nature into a real-time molecular dynamics simulation

    NASA Astrophysics Data System (ADS)

    Hasegawa, Taisuke

    2016-11-01

    We propose a novel molecular dynamics (MD) algorithm for approximately dealing with a nuclear quantum dynamics in a real-time MD simulation. We have found that real-time dynamics of the ensemble of classical particles acquires quantum nature by introducing a constant quantum mechanical uncertainty constraint on its classical dynamics. The constant uncertainty constraint is handled by the Lagrange multiplier method and implemented into a conventional MD algorithm. The resulting constant uncertainty molecular dynamics (CUMD) is applied to the calculation of quantum position autocorrelation functions on quartic and Morse potentials. The test calculations show that CUMD gives better performance than ring-polymer MD because of the inclusion of the quantum zero-point energy during real-time evolution as well as the quantum imaginary-time statistical effect stored in an initial condition. The CUMD approach will be a possible starting point for new real-time quantum dynamics simulation in condensed phase.

  20. Real-time remote sensing driven river basin modeling using radar altimetry

    NASA Astrophysics Data System (ADS)

    Pereira-Cardenal, S. J.; Riegels, N. D.; Berry, P. A. M.; Smith, R. G.; Yakovlev, A.; Siegfried, T. U.; Bauer-Gottwein, P.

    2011-01-01

    Many river basins have a weak in-situ hydrometeorological monitoring infrastructure. However, water resources practitioners depend on reliable hydrological models for management purposes. Remote sensing (RS) data have been recognized as an alternative to in-situ hydrometeorological data in remote and poorly monitored areas and are increasingly used to force, calibrate, and update hydrological models. In this study, we evaluate the potential of informing a river basin model with real-time radar altimetry measurements over reservoirs. We present a lumped, conceptual, river basin water balance modeling approach based entirely on RS and reanalysis data: precipitation was obtained from the Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA), temperature from the European Centre for Medium-Range Weather Forecast's (ECMWF) Operational Surface Analysis dataset and reference evapotranspiration was derived from temperature data. The Ensemble Kalman Filter was used to assimilate radar altimetry (ERS2 and Envisat) measurements of reservoir water levels. The modeling approach was applied to the Syr Darya River Basin, a snowmelt-dominated basin with large topographical variability, several large reservoirs and scarce hydrometeorological data that is located in Central Asia and shared between 4 countries with conflicting water management interests. The modeling approach was tested over a historical period for which in-situ reservoir water levels were available. Assimilation of radar altimetry data significantly improved the performance of the hydrological model. Without assimilation of radar altimetry data, model performance was limited, probably because of the size and complexity of the model domain, simplifications inherent in model design, and the uncertainty of RS and reanalysis data. Altimetry data assimilation reduced the mean absolute error of the simulated reservoir water levels from 4.7 to 1.9 m, and overall model RMSE from 10.3 m to 6

  1. Real-time remote sensing driven river basin modelling using radar altimetry

    NASA Astrophysics Data System (ADS)

    Pereira-Cardenal, S. J.; Riegels, N. D.; Berry, P. A. M.; Smith, R. G.; Yakovlev, A.; Siegfried, T. U.; Bauer-Gottwein, P.

    2010-10-01

    Many river basins have a weak in-situ hydrometeorological monitoring infrastructure. However, water resources practitioners depend on reliable hydrological models for management purposes. Remote sensing (RS) data have been recognized as an alternative to in-situ hydrometeorological data in remote and poorly monitored areas and are increasingly used to force, calibrate, and update hydrological models. In this study, we evaluate the potential of informing a river basin model with real-time radar altimetry measurements over reservoirs. We present a lumped, conceptual, river basin water balance modelling approach based entirely on RS and reanalysis data: precipitation was obtained from the Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA), temperature from the European Centre for Medium-Range Weather Forecast's (ECMWF) Operational Surface Analysis dataset and reference evapotranspiration was derived from temperature data. The Ensemble Kalman Filter was used to assimilate radar altimetry (ERS2 and Envisat) measurements of reservoir water levels. The modelling approach was applied to the Syr Darya River Basin, a snowmelt-dominated basin with large topographical variability, several large reservoirs and scarce hydrometeorological data that is shared between 4 countries with conflicting water management interests. The modelling approach was tested over a historical period for which in-situ reservoir water levels were available. Assimilation of radar altimetry data significantly improved the performance of the hydrological model. Without assimilation of radar altimetry data, model performance was limited, probably because of the size and complexity of the model domain, simplifications inherent in model design, and the uncertainty of RS and reanalysis data. Altimetry data assimilation reduced the mean error of the simulated reservoir water levels from 4.7 to 1.9 m, and overall model RMSE from 10.3 m to 6.7 m. Because of its easy

  2. Real-Time Mesoscale Modeling Over Antarctica: The Antarctic Mesoscale Prediction System*.

    NASA Astrophysics Data System (ADS)

    Powers, Jordan G.; Monaghan, Andrew J.; Cayette, Arthur M.; Bromwich, David H.; Kuo, Ying-Hwa; Manning, Kevin W.

    2003-11-01

    *Byrd Polar Research Center Contribution Number 1276In support of the United States Antarctic Program (USAP), the National Center for Atmospheric Research and the Byrd Polar Research Center of The Ohio State University have created the Antarctic Mesoscale Prediction System (AMPS): an experimental, real-time mesoscale modeling system covering Antarctica. AMPS has been designed to serve flight forecasters at McMurdo Station, to support science and operations around the continent, and to be a vehicle for the development of physical parameterizations suitable for polar regions. Since 2000, AMPS has been producing high-resolution forecasts (grids to 3.3 km) with the “Polar MM5,” a version of the fifth-generation Pennsylvania State University NCAR Mesoscale Model tuned for the polar atmosphere. Beyond its basic mission of serving the USAP flight forecasters at McMurdo, AMPS has assisted both in emergency operations to save lives and in programs to explore the extreme polar environment. The former have included a medical evacuation from the South Pole and a marine rescue from the continental margin. The latter have included scientific field campaigns and the daily activities of international Antarctic forecasters and researchers. The AMPS program has been a success in terms of advancing polar mesoscale NWP, serving critical logistical operations of the USAP, and, most visibly, assisting in emergency rescue missions to save lives. The history and performance of AMPS are described and the successes of this unique real-time mesoscale modeling system in crisis support are detailed.

  3. Modeling Real-Time Coordination of Distributed Expertise and Event Response in NASA Mission Control Center Operations

    NASA Astrophysics Data System (ADS)

    Onken, Jeffrey

    This dissertation introduces a multidisciplinary framework for the enabling of future research and analysis of alternatives for control centers for real-time operations of safety-critical systems. The multidisciplinary framework integrates functional and computational models that describe the dynamics in fundamental concepts of previously disparate engineering and psychology research disciplines, such as group performance and processes, supervisory control, situation awareness, events and delays, and expertise. The application in this dissertation is the real-time operations within the NASA Mission Control Center in Houston, TX. This dissertation operationalizes the framework into a model and simulation, which simulates the functional and computational models in the framework according to user-configured scenarios for a NASA human-spaceflight mission. The model and simulation generates data according to the effectiveness of the mission-control team in supporting the completion of mission objectives and detecting, isolating, and recovering from anomalies. Accompanying the multidisciplinary framework is a proof of concept, which demonstrates the feasibility of such a framework. The proof of concept demonstrates that variability occurs where expected based on the models. The proof of concept also demonstrates that the data generated from the model and simulation is useful for analyzing and comparing MCC configuration alternatives because an investigator can give a diverse set of scenarios to the simulation and the output compared in detail to inform decisions about the effect of MCC configurations on mission operations performance.

  4. Assimilation of Real-Time Satellite And Human Sensor Networks for Modeling Natural Disasters

    NASA Astrophysics Data System (ADS)

    Aulov, O.; Halem, M.; Lary, D. J.

    2011-12-01

    We describe the development of underlying technologies needed to address the merging of a web of real time satellite sensor Web (SSW) and Human Sensor Web (HSW) needed to augment the US response to extreme events. As an initial prototyping step and use case scenario, we consider the development of two major system tools that can be transitioned from research to the responding operational agency for mitigating coastal oil spills. These tools consist of the capture of Situation Aware (SA) Social Media (SM) Data, and assimilation of the processed information into forecasting models to provide incident decision managers with interactive virtual spatial temporal animations superimposed with probabilistic data estimates. The system methodologies are equally applicable to the wider class of extreme events such as plume dispersions from volcanoes or massive fires, major floods, hurricane impacts, radioactive isotope dispersions from nuclear accidents, etc. A successful feasibility demonstration of this technology has been shown in the case of the Deepwater Horizon Oil Spill where Human Sensor Networks have been combined with a geophysical model to perform parameter assessments. Flickr images of beached oil were mined from the spill area, geolocated and timestamped and converted into geophysical data. This data was incorporated into General NOAA Operational Modeling Environment (GNOME), a Lagrangian forecast model that uses near real-time surface winds, ocean currents, and satellite shape profiles of oil to generate a forecast of plume movement. As a result, improved estimates of diffusive coefficients and rates of oil spill were determined. Current approaches for providing satellite derived oil distributions are collected from a satellite sensor web of operational and research sensors from many countries, and a manual analysis is performed by NESDIS. A real time SA HSW processing system based on geolocated SM data from sources such as Twitter, Flickr, YouTube etc., greatly

  5. Numerical modelling for real-time forecasting of marine oil pollution and hazard assessment

    NASA Astrophysics Data System (ADS)

    De Dominicis, Michela; Pinardi, Nadia; Bruciaferri, Diego; Liubartseva, Svitlana

    2015-04-01

    (MEDESS4MS) system, which is an integrated operational multi-model oil spill prediction service, that can be used by different users to run simulations of oil spills at sea, even in real time, through a web portal. The MEDESS4MS system gathers different oil spill modelling systems and data from meteorological and ocean forecasting systems, as well as operational information on response equipment, together with environmental and socio-economic sensitivity maps. MEDSLIK-II has been also used to provide an assessment of hazard stemming from operational oil ship discharges in the Southern Adriatic and Northern Ionian (SANI) Seas. Operational pollution resulting from ships consists of a movable hazard with a magnitude that changes dynamically as a result of a number of external parameters varying in space and time (temperature, wind, sea currents). Simulations of oil releases have been performed with realistic oceanographic currents and the results show that the oil pollution hazard distribution has an inherent spatial and temporal variability related to the specific flow field variability.

  6. Real-Time, Model-Based Spray-Cooling Control System for Steel Continuous Casting

    NASA Astrophysics Data System (ADS)

    Petrus, Bryan; Zheng, Kai; Zhou, X.; Thomas, Brian G.; Bentsman, Joseph

    2011-02-01

    This article presents a new system to control secondary cooling water sprays in continuous casting of thin steel slabs (CONONLINE). It uses real-time numerical simulation of heat transfer and solidification within the strand as a software sensor in place of unreliable temperature measurements. The one-dimensional finite-difference model, CON1D, is adapted to create the real-time predictor of the slab temperature and solidification state. During operation, the model is updated with data collected by the caster automation systems. A decentralized controller configuration based on a bank of proportional-integral controllers with antiwindup is developed to maintain the shell surface-temperature profile at a desired set point. A new method of set-point generation is proposed to account for measured mold heat flux variations. A user-friendly monitor visualizes the results and accepts set-point changes from the caster operator. Example simulations demonstrate how a significantly better shell surface-temperature control is achieved.

  7. Near infrared spectroscopic calibration models for real time monitoring of powder density.

    PubMed

    Román-Ospino, Andrés D; Singh, Ravendra; Ierapetritou, Marianthi; Ramachandran, Rohit; Méndez, Rafael; Ortega-Zuñiga, Carlos; Muzzio, Fernando J; Romañach, Rodolfo J

    2016-10-15

    Near infrared spectroscopic (NIRS) calibration models for real time prediction of powder density (tap, bulk and consolidated) were developed for a pharmaceutical formulation. Powder density is a critical property in the manufacturing of solid oral dosages, related to critical quality attributes such as tablet mass, hardness and dissolution. The establishment of calibration techniques for powder density is highly desired towards the development of control strategies. Three techniques were evaluated to obtain the required variation in powder density for calibration sets: 1) different tap density levels (for a single component), 2) generating different strain levels in powders blends (and as consequence powder density), through a modified shear Couette Cell, and 3) applying normal forces during a compressibility test with a powder rheometer to a pharmaceutical blend. For each variation in powder density, near infrared spectra were acquired to develop partial least squares (PLS) calibration models. Test samples were predicted with a relative standard error of prediction of 0.38%, 7.65% and 0.93% for tap density (single component), shear and rheometer respectively. Spectra obtained in real time in a continuous manufacturing (CM) plant were compared to the spectra from the three approaches used to vary powder density. The calibration based on the application of different strain levels showed the greatest similarity with the blends produced in the CM plant.

  8. A model-based technique for integrated real-time profile control in the JET tokamak

    NASA Astrophysics Data System (ADS)

    Laborde, L.; Mazon, D.; Moreau, D.; Murari, A.; Felton, R.; Zabeo, L.; Albanese, R.; Ariola, M.; Bucalossi, J.; Crisanti, F.; de Baar, M.; de Tommasi, G.; de Vries, P.; Joffrin, E.; Lennholm, M.; Litaudon, X.; Pironti, A.; Tala, T.; Tuccillo, A.

    2005-01-01

    This paper describes a new technique which has been implemented on the JET tokamak to investigate integrated real-time control of several plasma profiles simultaneously (such as current, temperature and pressure) and reports the results of the first experimental tests. The profiles are handled through their projection on a suitable basis of functions according to the Galerkin scheme. Their response to three actuators (heating and current drive powers injected in the plasma) is linearized in an experimentally deduced multi-input multi-output model. The singular value decomposition of this model operator allows us to design a distributed-parameter real-time controller which maximizes the steady state decoupling of the multiple feedback loops. It enables us to control several coupled profiles simultaneously, with some degree of fuzziness to let the plasma evolve towards an accessible non-linear state which is the closest to the requested one, despite a limited number of actuators. The first experiments using these techniques show that different current and electron temperature profiles can be obtained and sustained by the controller during a closed-loop operation time window. Future improvements and perspectives are briefly mentioned.

  9. Drosophila Embryos as Model Systems for Monitoring Bacterial Infection in Real Time

    PubMed Central

    Evans, Iwan R.; Waterfield, Nicholas; ffrench-Constant, Richard H.; Wood, Will

    2009-01-01

    Drosophila embryos are well studied developmental microcosms that have been used extensively as models for early development and more recently wound repair. Here we extend this work by looking at embryos as model systems for following bacterial infection in real time. We examine the behaviour of injected pathogenic (Photorhabdus asymbiotica) and non-pathogenic (Escherichia coli) bacteria and their interaction with embryonic hemocytes using time-lapse confocal microscopy. We find that embryonic hemocytes both recognise and phagocytose injected wild type, non-pathogenic E. coli in a Dscam independent manner, proving that embryonic hemocytes are phagocytically competent. In contrast, injection of bacterial cells of the insect pathogen Photorhabdus leads to a rapid ‘freezing’ phenotype of the hemocytes associated with significant rearrangement of the actin cytoskeleton. This freezing phenotype can be phenocopied by either injection of the purified insecticidal toxin Makes Caterpillars Floppy 1 (Mcf1) or by recombinant E. coli expressing the mcf1 gene. Mcf1 mediated hemocyte freezing is shibire dependent, suggesting that endocytosis is required for Mcf1 toxicity and can be modulated by dominant negative or constitutively active Rac expression, suggesting early and unexpected effects of Mcf1 on the actin cytoskeleton. Together these data show how Drosophila embryos can be used to track bacterial infection in real time and how mutant analysis can be used to genetically dissect the effects of specific bacterial virulence factors. PMID:19609447

  10. A real-time emergency response workstation using a 3-D numerical model initialized with sodar

    SciTech Connect

    Lawver, B.S.; Sullivan, T.J.; Baskett, R.L.

    1993-01-28

    Many emergency response dispersion modeling systems provide simple Gaussian models driven by single meteorological tower inputs to estimate the downwind consequences from accidental spills or stack releases. Complex meteorological or terrain settings demand more sophisticated resolution of the three-dimensional structure of the atmosphere to reliably calculate plume dispersion. Mountain valleys and sea breeze flows are two common examples of such settings. To address these complexities, the authors have implemented the three-dimensional diagnostic MATHEW mass-adjusted wind field and ADPIC particle-in-cell dispersion models on a workstation for use in real-time emergency response modeling. MATHEW/ADPIC have shown their utility in a variety of complex settings over the last 15 years within the Department of Energy`s Atmospheric Release Advisory Capability (ARAC) project. The models are initialized using an array of surface wind measurements from meteorological towers coupled with vertical profiles from an acoustic sounder (sodar). The workstation automatically acquires the meteorological data every 15 minutes. A source term is generated using either defaults or a real-time stack monitor. Model outputs include contoured isopleths displayed on site geography or plume densities shown over 3-D color shaded terrain. The models are automatically updated every 15 minutes to provide the emergency response manager with a continuous display of potentially hazardous ground-level conditions if an actual release were to occur. Model run time is typically less than 2 minutes on 6 megaflop ({approximately}30 MIPS) workstations. Data acquisition, limited by dial-up modem communications, requires 3 to 5 minutes.

  11. Toward a Global Model for Predicting Earthquake-Induced Landslides in Near-Real Time

    NASA Astrophysics Data System (ADS)

    Nowicki, M. A.; Wald, D. J.; Hamburger, M. W.; Hearne, M.; Thompson, E.

    2013-12-01

    We present a newly developed statistical model for estimating the distribution of earthquake-triggered landslides in near-real time, which is designed for use in the USGS Prompt Assessment of Global Earthquakes for Response (PAGER) and ShakeCast systems. We use standardized estimates of ground shaking from the USGS ShakeMap Atlas 2.0 to develop an empirical landslide probability model by combining shaking estimates with broadly available landslide susceptibility proxies, including topographic slope, surface geology, and climatic parameters. While the initial model was based on four earthquakes for which digitally mapped landslide inventories and well constrained ShakeMaps are available--the Guatemala (1976), Northridge, California (1994), Chi-Chi, Taiwan (1999), and Wenchuan, China (2008) earthquakes, our improved model includes observations from approximately ten other events from a variety of tectonic and geomorphic settings for which we have obtained landslide inventories. Using logistic regression, this database is used to build a predictive model of the probability of landslide occurrence. We assess the performance of the regression model using statistical goodness-of-fit metrics to determine which combination of the tested landslide proxies provides the optimum prediction of observed landslides while minimizing ';false alarms' in non-landslide zones. Our initial results indicate strong correlations with peak ground acceleration and maximum slope, and weaker correlations with surface geological and soil wetness proxies. In terms of the original four events included, the global model predicts landslides most accurately when applied to the Wenchuan and Chi-Chi events, and less accurately when applied to the Northridge and Guatemala datasets. Combined with near-real time ShakeMaps, the model can be used to make generalized predictions of whether or not landslides are likely to occur (and if so, where) for future earthquakes around the globe, and these estimates

  12. Real-time Ensemble Forecasting of Coronal Mass Ejections using the WSA-ENLIL+Cone Model

    NASA Astrophysics Data System (ADS)

    Mays, M. L.; Taktakishvili, A.; Pulkkinen, A. A.; MacNeice, P. J.; Rastaetter, L.; Kuznetsova, M. M.; Odstrcil, D.

    2013-12-01

    Ensemble forecasting of coronal mass ejections (CMEs) provides significant information in that it provides an estimation of the spread or uncertainty in CME arrival time predictions due to uncertainties in determining CME input parameters. Ensemble modeling of CME propagation in the heliosphere is performed by forecasters at the Space Weather Research Center (SWRC) using the WSA-ENLIL cone model available at the Community Coordinated Modeling Center (CCMC). SWRC is an in-house research-based operations team at the CCMC which provides interplanetary space weather forecasting for NASA's robotic missions and performs real-time model validation. A distribution of n (routinely n=48) CME input parameters are generated using the CCMC Stereo CME Analysis Tool (StereoCAT) which employs geometrical triangulation techniques. These input parameters are used to perform n different simulations yielding an ensemble of solar wind parameters at various locations of interest (satellites or planets), including a probability distribution of CME shock arrival times (for hits), and geomagnetic storm strength (for Earth-directed hits). Ensemble simulations have been performed experimentally in real-time at the CCMC since January 2013. We present the results of ensemble simulations for a total of 15 CME events, 10 of which were performed in real-time. The observed CME arrival was within the range of ensemble arrival time predictions for 5 out of the 12 ensemble runs containing hits. The average arrival time prediction was computed for each of the twelve ensembles predicting hits and using the actual arrival time an average absolute error of 8.20 hours was found for all twelve ensembles, which is comparable to current forecasting errors. Some considerations for the accuracy of ensemble CME arrival time predictions include the importance of the initial distribution of CME input parameters, particularly the mean and spread. When the observed arrivals are not within the predicted range, this

  13. Dynamic keyhole: A novel method to improve MR images in the presence of respiratory motion for real-time MRI

    SciTech Connect

    Lee, Danny; Pollock, Sean; Whelan, Brendan; Keall, Paul; Kim, Taeho

    2014-07-15

    Purpose: In this work, the authors present a novel magnetic resonance imaging reconstruction method to improve the quality of MR images in the presence of respiratory motion for real-time thoracic image-guided radiotherapy. Methods: This new reconstruction method is called dynamic keyhole and utilizes a library of previously acquired, peripheral k-space datasets from the same (or similar) respiratory state in conjunction with central k-space datasets acquired in real-time. Internal or external respiratory signals are utilized to sort, match, and combine the two separate peripheral and central k-space datasets with respect to respiratory displacement, thereby reducing acquisition time and improving image quality without respiratory-related artifacts. In this study, the dynamic keyhole, conventional keyhole, and zero-filling methods were compared to full k-space acquisition (ground truth) for 60 coronal datasets acquired from 15 healthy human subjects. Results: For the same image-quality difference from the ground-truth image, the dynamic keyhole method reused 79% of the prior peripheral phase-encoding lines, while the conventional keyhole reused 73% and zero-filling 63% (p-value < 0.0001), corresponding to faster acquisition speed of dynamic keyhole for real-time imaging applications. Conclusions: This study demonstrates that the dynamic keyhole method is a promising technique for clinical applications such as image-guided radiotherapy requiring real-time MR monitoring of the thoracic region. Based on the results from this study, the dynamic keyhole method could increase the temporal resolution by a factor of five compared with full k-space methods.

  14. V/STOL tilt rotor aircraft study mathematical model for a real time simulation of a tilt rotor aircraft (Boeing Vertol Model 222), volume 8

    NASA Technical Reports Server (NTRS)

    Rosenstein, H.; Mcveigh, M. A.; Mollenkof, P. A.

    1973-01-01

    A mathematical model for a real time simulation of a tilt rotor aircraft was developed. The mathematical model is used for evaluating aircraft performance and handling qualities. The model is based on an eleven degree of freedom total force representation. The rotor is treated as a point source of forces and moments with appropriate response time lags and actuator dynamics. The aerodynamics of the wing, tail, rotors, landing gear, and fuselage are included.

  15. The Drive-Reinforcement Neuronal Model: A Real-Time Learning Mechanism For Unsupervised Learning

    NASA Astrophysics Data System (ADS)

    Klopf, A. H.

    1988-05-01

    The drive-reinforcement neuronal model is described as an example of a newly discovered class of real-time learning mechanisms that correlate earlier derivatives of inputs with later derivatives of outputs. The drive-reinforcement neuronal model has been demonstrated to predict a wide range of classical conditioning phenomena in animal learning. A variety of classes of connectionist and neural network models have been investigated in recent years (Hinton and Anderson, 1981; Levine, 1983; Barto, 1985; Feldman, 1985; Rumelhart and McClelland, 1986). After a brief review of these models, discussion will focus on the class of real-time models because they appear to be making the strongest contact with the experimental evidence of animal learning. Theoretical models in physics have inspired Boltzmann machines (Ackley, Hinton, and Sejnowski, 1985) and what are sometimes called Hopfield networks (Hopfield, 1982; Hopfield and Tank, 1986). These connectionist models utilize symmetric connections and adaptive equilibrium processes during which the networks settle into minimal energy states. Networks utilizing error-correction learning mechanisms go back to Rosenblatt's (1962) perception and Widrow's (1962) adaline and currently take the form of back propagation networks (Parker, 1985; Rumelhart, Hinton, and Williams, 1985, 1986). These networks require a "teacher" or "trainer" to provide error signals indicating the difference between desired and actual responses. Networks employing real-time learning mechanisms, in which the temporal association of signals is of fundamental importance, go back to Hebb (1949). Real-time learning mechanisms may require no teacher or trainer and thus may lend themselves to unsupervised learning. Such models have been extended by Klopf (1972, 1982), who introduced the notions of synaptic eligibility and generalized reinforcement. Sutton and Barto (1981) advanced this class of models by proposing that a derivative of the theoretical neuron's out

  16. Surrogate Modeling of High-Fidelity Fracture Simulations for Real-Time Residual Strength Predictions

    NASA Technical Reports Server (NTRS)

    Spear, Ashley D.; Priest, Amanda R.; Veilleux, Michael G.; Ingraffea, Anthony R.; Hochhalter, Jacob D.

    2011-01-01

    A surrogate model methodology is described for predicting in real time the residual strength of flight structures with discrete-source damage. Starting with design of experiment, an artificial neural network is developed that takes as input discrete-source damage parameters and outputs a prediction of the structural residual strength. Target residual strength values used to train the artificial neural network are derived from 3D finite element-based fracture simulations. A residual strength test of a metallic, integrally-stiffened panel is simulated to show that crack growth and residual strength are determined more accurately in discrete-source damage cases by using an elastic-plastic fracture framework rather than a linear-elastic fracture mechanics-based method. Improving accuracy of the residual strength training data would, in turn, improve accuracy of the surrogate model. When combined, the surrogate model methodology and high-fidelity fracture simulation framework provide useful tools for adaptive flight technology.

  17. Near real time weather and ocean model data access with rNOMADS

    NASA Astrophysics Data System (ADS)

    Bowman, D. C.; Lees, J. M.

    2015-05-01

    The National Oceanic and Atmospheric Administration Operational Model Archive and Distribution System (NOMADS) facilitates rapid delivery of real time and archived atmospheric and oceanic model outputs from multiple agencies. These data are free to the scientific community, industry, and the public. The rNOMADS package provides an interface between NOMADS and the R programming language. Like R itself, rNOMADS is open source and cross platform. It utilizes server-side functionality on the NOMADS system to subset model outputs for delivery to client R users. We discuss rNOMADS implementation and usage as well as provide two case studies. Users can download rNOMADS from within the R interpreter or from the Comprehensive R Archive Network (CRAN).

  18. Development of a globally applicable model for near real-time prediction of seismically induced landslides

    USGS Publications Warehouse

    Nowicki, M. Anna; Wald, David J.; Hamburger, Michael W.; Hearne, Mike; Thompson, Eric M.

    2014-01-01

    Substantial effort has been invested to understand where seismically induced landslides may occur in the future, as they are a costly and frequently fatal threat in mountainous regions. The goal of this work is to develop a statistical model for estimating the spatial distribution of landslides in near real-time around the globe for use in conjunction with the U.S. Geological Survey (USGS) Prompt Assessment of Global Earthquakes for Response (PAGER) system. This model uses standardized outputs of ground shaking from the USGS ShakeMap Atlas 2.0 to develop an empirical landslide probability model, combining shaking estimates with broadly available landslide susceptibility proxies, i.e., topographic slope, surface geology, and climate parameters. We focus on four earthquakes for which digitally mapped landslide inventories and well-constrainedShakeMaps are available. The resulting database is used to build a predictive model of the probability of landslide occurrence. The landslide database includes the Guatemala (1976), Northridge (1994), Chi-Chi (1999), and Wenchuan (2008) earthquakes. Performance of the regression model is assessed using statistical goodness-of-fit metrics and a qualitative review to determine which combination of the proxies provides both the optimum prediction of landslide-affected areas and minimizes the false alarms in non-landslide zones. Combined with near real-time ShakeMaps, these models can be used to make generalized predictions of whether or not landslides are likely to occur (and if so, where) for earthquakes around the globe, and eventually to inform loss estimates within the framework of the PAGER system.

  19. Applications For Real Time NOMADS At NCEP To Disseminate NOAA's Operational Model Data Base

    NASA Astrophysics Data System (ADS)

    Alpert, J. C.; Wang, J.; Rutledge, G.

    2007-05-01

    A wide range of environmental information, in digital form, with metadata descriptions and supporting infrastructure is contained in the NOAA Operational Modeling Archive Distribution System (NOMADS) and its Real Time (RT) project prototype at the National Centers for Environmental Prediction (NCEP). NOMADS is now delivering on its goal of a seamless framework, from archival to real time data dissemination for NOAA's operational model data holdings. A process is under way to make NOMADS part of NCEP's operational production of products. A goal is to foster collaborations among the research and education communities, value added retailers, and public access for science and development. In the National Research Council's "Completing the Forecast", Recommendation 3.4 states: "NOMADS should be maintained and extended to include (a) long-term archives of the global and regional ensemble forecasting systems at their native resolution, and (b) re-forecast datasets to facilitate post-processing." As one of many participants of NOMADS, NCEP serves the operational model data base using data application protocol (Open-DAP) and other services for participants to serve their data sets and users to obtain them. Using the NCEP global ensemble data as an example, we show an Open-DAP (also known as DODS) client application that provides a request-and-fulfill mechanism for access to the complex ensemble matrix of holdings. As an example of the DAP service, we show a client application which accesses the Global or Regional Ensemble data set to produce user selected weather element event probabilities. The event probabilities are easily extended over model forecast time to show probability histograms defining the future trend of user selected events. This approach insures an efficient use of computer resources because users transmit only the data necessary for their tasks. Data sets are served by OPeN-DAP allowing commercial clients such as MATLAB or IDL as well as freeware clients

  20. An ex vivo laser-induced spinal cord injury model to assess mechanisms of axonal degeneration in real-time.

    PubMed

    Okada, Starlyn L M; Stivers, Nicole S; Stys, Peter K; Stirling, David P

    2014-11-25

    Injured CNS axons fail to regenerate and often retract away from the injury site. Axons spared from the initial injury may later undergo secondary axonal degeneration. Lack of growth cone formation, regeneration, and loss of additional myelinated axonal projections within the spinal cord greatly limits neurological recovery following injury. To assess how central myelinated axons of the spinal cord respond to injury, we developed an ex vivo living spinal cord model utilizing transgenic mice that express yellow fluorescent protein in axons and a focal and highly reproducible laser-induced spinal cord injury to document the fate of axons and myelin (lipophilic fluorescent dye Nile Red) over time using two-photon excitation time-lapse microscopy. Dynamic processes such as acute axonal injury, axonal retraction, and myelin degeneration are best studied in real-time. However, the non-focal nature of contusion-based injuries and movement artifacts encountered during in vivo spinal cord imaging make differentiating primary and secondary axonal injury responses using high resolution microscopy challenging. The ex vivo spinal cord model described here mimics several aspects of clinically relevant contusion/compression-induced axonal pathologies including axonal swelling, spheroid formation, axonal transection, and peri-axonal swelling providing a useful model to study these dynamic processes in real-time. Major advantages of this model are excellent spatiotemporal resolution that allows differentiation between the primary insult that directly injures axons and secondary injury mechanisms; controlled infusion of reagents directly to the perfusate bathing the cord; precise alterations of the environmental milieu (e.g., calcium, sodium ions, known contributors to axonal injury, but near impossible to manipulate in vivo); and murine models also offer an advantage as they provide an opportunity to visualize and manipulate genetically identified cell populations and subcellular

  1. Validation of real-time PCR assays for bioforensic detection of model plant pathogens.

    PubMed

    James, Mindy; Blagden, Trenna; Moncrief, Ian; Burans, James P; Schneider, Katherine; Fletcher, Jacqueline

    2014-03-01

    The U.S. agricultural sector is vulnerable to intentionally introduced microbial threats because of its wide and open distribution and economic importance. To investigate such events, forensically valid assays for plant pathogen detection are needed. In this work, real-time PCR assays were developed for three model plant pathogens: Pseudomonas syringae pathovar tomato, Xylella fastidiosa, and Wheat streak mosaic virus. Validation included determination of the linearity and range, limit of detection, sensitivity, specificity, and exclusivity of each assay. Additionally, positive control plasmids, distinguishable from native signature by restriction enzyme digestion, were developed to support forensic application of the assays. Each assay displayed linear amplification of target nucleic acid, detected 100 fg or less of target nucleic acid, and was specific to its target pathogen. Results obtained with these model pathogens provide the framework for development and validation of similar assays for other plant pathogens of high consequence.

  2. A new device for real time monitoring of microbial population dynamics during in situ and ex situ bioremediation

    SciTech Connect

    Woodward, R.E.; Malone, R.W.

    1995-12-31

    Monitoring of microbial population dynamics is an important operating parameter for successful bioremediation projects. The traditional method of plate counts or most probable number (MPN) requires 2 to 7 days for development and therefore provides a historical measurement of little real-time operational significance. Selected enzyme activity is directly proportional to microbial population density and is linear in the population range from 10{sub 4} to 10{sup 8} CFU/mL. This paper summarizes the use of this enzyme based, real-time measurement of microbial population dynamics for the management of four bioremediation projects: (1) differentiation of assimilation from nitrification during the metabolism of ammonia in an industrial waste stream, (2) treatability assessment and management of activated sludge processes during the treatment of a hazardous, petrochemical waste, (3) measurement of intrinsic microbial activity in soil cores at a spill site, and (4) non-invasive monitoring of microbial populations during in situ bioremediation of two aquifers.

  3. Real time hybrid simulation with online model updating: An analysis of accuracy

    NASA Astrophysics Data System (ADS)

    Ou, Ge; Dyke, Shirley J.; Prakash, Arun

    2017-02-01

    In conventional hybrid simulation (HS) and real time hybrid simulation (RTHS) applications, the information exchanged between the experimental substructure and numerical substructure is typically restricted to the interface boundary conditions (force, displacement, acceleration, etc.). With additional demands being placed on RTHS and recent advances in recursive system identification techniques, an opportunity arises to improve the fidelity by extracting information from the experimental substructure. Online model updating algorithms enable the numerical model of components (herein named the target model), that are similar to the physical specimen to be modified accordingly. This manuscript demonstrates the power of integrating a model updating algorithm into RTHS (RTHSMU) and explores the possible challenges of this approach through a practical simulation. Two Bouc-Wen models with varying levels of complexity are used as target models to validate the concept and evaluate the performance of this approach. The constrained unscented Kalman filter (CUKF) is selected for using in the model updating algorithm. The accuracy of RTHSMU is evaluated through an estimation output error indicator, a model updating output error indicator, and a system identification error indicator. The results illustrate that, under applicable constraints, by integrating model updating into RTHS, the global response accuracy can be improved when the target model is unknown. A discussion on model updating parameter sensitivity to updating accuracy is also presented to provide guidance for potential users.

  4. Dynamics of traffic flows on crossing roads induced by real-time information

    NASA Astrophysics Data System (ADS)

    Fukui, Minoru; Ishibashi, Yoshihiro; Nishinari, Katsuhiro

    2013-02-01

    Traffic flows on crossing roads with an information board installed at the intersection have been simulated by a cellular automaton model. In the model, drivers have to enter the road with a shorter trip-time indicated on the information board, by making a turn at the intersection if necessary. The movement of drivers induces various traffic states, which are classified into six phases as a function of the car density. The dynamics of the traffic is expressed as the return map in the density-flow space, and analyzed on the basis of the car configuration on the roads.

  5. Review of RT-LAB and Steps Involved for Implementation of a Simulink Model from MATLAB to REAL-TIME

    NASA Astrophysics Data System (ADS)

    Mikkili, Suresh; Panda, Anup Kumar

    2013-11-01

    In recent days, every researcher wants to develop his/her model in real-time. Simulation tools have been widely used for the design and improvement of electrical systems since the mid-twentieth century. The evolution of simulation tools has progressed in step with the evolution of computing technologies. Now a days, computing technologies have improved dramatically in performance and become widely available at a steadily decreasing cost. Consequently, simulation tools have also seen dramatic performance gains and steady cost decreases. Researchers and engineers now have access to affordable, high-performance simulation tools that were previously too cost prohibitive, except for the largest manufacturers and utilities.This article has introduced a specific class of digital simulator known as a real-time simulator by answering the questions "What is real-time simulation?" "Why is it needed" and "How it works". The latest trend in real-time simulation consists of exporting simulation models to FPGA. In this article, the steps involved for implementation of a model from MATLAB to REAL-TIME are provided in detail. The detailed real-time results are presented to support the feasibility of real-time digital simulator.

  6. Toward Global Real Time Hydrologic Modeling - An "Open" View From the Trenches

    NASA Astrophysics Data System (ADS)

    Nelson, J.

    2015-12-01

    Big Data has become a popular term to describe the exponential growth of data and related cyber infrastructure to process it so that better analysis can be performed and lead to improved decision-making. How are we doing in the hydrologic sciences? As part of a significant collaborative effort that brought together scientists from public, private, and academic organizations a new transformative hydrologic forecasting modeling infrastructure has been developed. How was it possible to go from deterministic hydrologic forecasts largely driven through manual interactions at 3600 stations to automated 15-day ensemble forecasts at 2.67 million stations? Earth observations of precipitation, temperature, moisture, and other atmospheric and land surface conditions form the foundation of global hydrologic forecasts, but this project demonstrates a critical component to harness these resources can be summed up in one word: OPEN. Whether it is open data sources, open software solutions with open standards, or just being open to collaborations and building teams across institutions, disciplines, and international boundaries, time and time again through my involvement in the development of a high-resolution real time global hydrologic forecasting model I have discovered that in every aspect the sum has always been greater than the parts. While much has been accomplished, much more remains to be done, but the most important lesson learned has been to the degree that we can remain open and work together, the greater our ability will be to use big data hydrologic modeling resources to solve the world's most vexing water related challenges. This presentation will demonstrate a transformational global real time hydrologic forecasting application based on downscaled ECMWF ensemble forecasts, RAPID routing, and Tethys Platform for cloud computing and visualization with discussions of the human and cyber infrastructure connections that make it successful and needs moving forward.

  7. A Real-Time MODIS Vegetation Composite for Land Surface Models and Short-Term Forecasting

    NASA Technical Reports Server (NTRS)

    Case, Jonathan L.; LaFontaine, Frank J.; Kumar, Sujay V.; Jedlovec, Gary J.

    2011-01-01

    The NASA Short-term Prediction Research and Transition (SPoRT) Center is producing real-time, 1- km resolution Normalized Difference Vegetation Index (NDVI) gridded composites over a Continental U.S. domain. These composites are updated daily based on swath data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor aboard the polar orbiting NASA Aqua and Terra satellites, with a product time lag of about one day. A simple time-weighting algorithm is applied to the NDVI swath data that queries the previous 20 days of data to ensure a continuous grid of data populated at all pixels. The daily composites exhibited good continuity both spatially and temporally during June and July 2010. The composites also nicely depicted high greenness anomalies that resulted from significant rainfall over southwestern Texas, Mexico, and New Mexico during July due to early-season tropical cyclone activity. The SPoRT Center is in the process of computing greenness vegetation fraction (GVF) composites from the MODIS NDVI data at the same spatial and temporal resolution for use in the NASA Land Information System (LIS). The new daily GVF dataset would replace the monthly climatological GVF database (based on Advanced Very High Resolution Radiometer [AVHRR] observations from 1992-93) currently available to the Noah land surface model (LSM) in both LIS and the public version of the Weather Research and Forecasting (WRF) model. The much higher spatial resolution (1 km versus 0.15 degree) and daily updates based on real-time satellite observations have the capability to greatly improve the simulation of the surface energy budget in the Noah LSM within LIS and WRF. Once code is developed in LIS to incorporate the daily updated GVFs, the SPoRT Center will conduct simulation sensitivity experiments to quantify the impacts and improvements realized by the MODIS real-time GVF data. This presentation will describe the methodology used to develop the 1-km MODIS NDVI composites and

  8. A real-time inverse quantised transform for multi-standard with dynamic resolution support

    NASA Astrophysics Data System (ADS)

    Sun, Chi-Chia; Lin, Chun-Ying; Zhang, Ce

    2016-06-01

    In this paper, a real-time configurable intelligent property (IP) core is presented for image/video decoding process in compatibility with the standard MPEG-4 Visual and the standard H.264/AVC. The inverse quantised discrete cosine and integer transform can be used to perform inverse quantised discrete cosine transform and inverse quantised inverse integer transforms which only required shift and add operations. Meanwhile, COordinate Rotation DIgital Computer iterations and compensation steps are adjustable in order to compensate for the video compression quality regarding various data throughput. The implementations are embedded in publicly available software XVID Codes 1.2.2 for the standard MPEG-4 Visual and the H.264/AVC reference software JM 16.1, where the experimental results show that the balance between the computational complexity and video compression quality is retained. At the end, FPGA synthesised results show that the proposed IP core can bring advantages to low hardware costs and also provide real-time performance for Full HD and 4K-2K video decoding.

  9. Dissolution Dynamic Nuclear Polarization Instrumentation for Real-time Enzymatic Reaction Rate Measurements by NMR.

    PubMed

    Balzan, Riccardo; Fernandes, Laetitia; Comment, Arnaud; Pidial, Laetitia; Tavitian, Bertrand; Vasos, Paul R

    2016-02-23

    The main limitation of NMR-based investigations is low sensitivity. This prompts for long acquisition times, thus preventing real-time NMR measurements of metabolic transformations. Hyperpolarization via dissolution DNP circumvents part of the sensitivity issues thanks to the large out-of-equilibrium nuclear magnetization stemming from the electron-to-nucleus spin polarization transfer. The high NMR signal obtained can be used to monitor chemical reactions in real time. The downside of hyperpolarized NMR resides in the limited time window available for signal acquisition, which is usually on the order of the nuclear spin longitudinal relaxation time constant, T1, or, in favorable cases, on the order of the relaxation time constant associated with the singlet-state of coupled nuclei, TLLS. Cellular uptake of endogenous molecules and metabolic rates can provide essential information on tumor development and drug response. Numerous previous hyperpolarized NMR studies have demonstrated the relevancy of pyruvate as a metabolic substrate for monitoring enzymatic activity in vivo. This work provides a detailed description of the experimental setup and methods required for the study of enzymatic reactions, in particular the pyruvate-to-lactate conversion rate in presence of lactate dehydrogenase (LDH), by hyperpolarized NMR.

  10. Detection of real-time dynamics of drug-target interactions by ultralong nanowalls.

    PubMed

    Menzel, Andreas; Gübeli, Raphael J; Güder, Firat; Weber, Wilfried; Zacharias, Margit

    2013-11-07

    Detecting drug-target interactions in real-time is a powerful approach for drug discovery and analytics. We show here for the first time the ultra fast electrical real-time detection and quantification of antibiotics using a novel biohybrid nanosensor. The biomolecular sensing is performed on ultralong (mm range) high aspect ratio nanowall (50 nm width) surfaces functionalized with operator DNA tetO which is specifically bound by the sensor protein TetR. This sensor protein is released from the operator DNA in a dose dependent manner by exposing the device functionalized with this bound DNA-protein complex to tetracycline antibiotics. As a result, the electrical conductance is accordingly modulated by these surface net charge changes. The switching mechanism of sensor proteins attached at the functionalized surfaces and releasing them again by antibiotics is demonstrated. With the here presented device the detection limit is below the limits of prevailing detection methods. Moreover, the study is extended to detect antibiotic residues in spiked organic milk from cows far below the maximum residual level of the European Union. In spiked milk samples a detection limit for tetracycline concentrations in the 100 fM level was achieved. The nanowall devices are fabricated by atomic layer deposition-based spacer lithography on full wafer scale which is a simple approach capable for mass production.

  11. Real-Time Nanoscale Open-Circuit Voltage Dynamics of Perovskite Solar Cells.

    PubMed

    Garrett, Joseph L; Tennyson, Elizabeth M; Hu, Miao; Huang, Jinsong; Munday, Jeremy N; Leite, Marina S

    2017-03-10

    Hybrid organic-inorganic perovskites based on methylammonium lead (MAPbI3) are an emerging material with great potential for high-performance and low-cost photovoltaics. However, for perovskites to become a competitive and reliable solar cell technology their instability and spatial variation must be understood and controlled. While the macroscopic characterization of the devices as a function of time is very informative, a nanoscale identification of their real-time local optoelectronic response is still missing. Here, we implement a four-dimensional imaging method through illuminated heterodyne Kelvin probe force microscopy to spatially (<50 nm) and temporally (16 s/scan) resolve the voltage of perovskite solar cells in a low relative humidity environment. Local open-circuit voltage (Voc) images show nanoscale sites with voltage variation >300 mV under 1-sun illumination. Surprisingly, regions of voltage that relax in seconds and after several minutes consistently coexist. Time-dependent changes of the local Voc are likely due to intragrain ion migration and are reversible at low injection level. These results show for the first time the real-time transient behavior of the Voc in perovskite solar cells at the nanoscale. Understanding and controlling the light-induced electrical changes that affect device performance are critical to the further development of stable perovskite-based solar technologies.

  12. A Multi-Model Real Time Forecasting Prototype System in the Mara Basin (Kenya/Tanzania)

    NASA Astrophysics Data System (ADS)

    Serrat-Capdevila, A.; Valdes, J. B.; Valdes, R.; Demaria, E. M.; Durcik, M.; Maitaria, K.; Roy, T.

    2013-12-01

    Remote sensing data and hydrologic models can respond to monitoring and forecasting needs in Africa and other poorly gauged regions. We present here the progress to date in developing a multi-model platform to provide hydrologic monitoring and forecasting using real time remote sensing observations. Satellite precipitation products such as CMORPH, TMPA (at 0.25° resolution) and PERSIANN-CCS (at 4km resolution) are used to force two models of different structure. One model is physically based and distributed, and the other is conceptual and lumped at the sub-basin level. The performance of both models is evaluated using different metrics, and the uncertainty in their predictions based on the errors incurred during the historical simulations period is computed. The models were compared and the potential increase in performance from using both models versus a single one will be assessed. This work provides insights into the advantages of a multi-model platform over a single model, with respect to different management and decision-making purposes. The methods were applied to the Mara Basin (Kenya/Tanzania), where growing human demands on water and land use are likely to alter significantly the hydrologic balance of the basin and the ecosystems that depend on it. These efforts are part of the Applied Sciences Team of the NASA SERVIR Program in collaboration with its East Africa Hub at the Regional Center for Mapping of Resources for Development (Nairobi,Kenya).

  13. The NIST Real-Time Control System (RCS): A Reference Model Architecture for Computational Intelligence

    NASA Technical Reports Server (NTRS)

    Albus, James S.

    1996-01-01

    The Real-time Control System (RCS) developed at NIST and elsewhere over the past two decades defines a reference model architecture for design and analysis of complex intelligent control systems. The RCS architecture consists of a hierarchically layered set of functional processing modules connected by a network of communication pathways. The primary distinguishing feature of the layers is the bandwidth of the control loops. The characteristic bandwidth of each level is determined by the spatial and temporal integration window of filters, the temporal frequency of signals and events, the spatial frequency of patterns, and the planning horizon and granularity of the planners that operate at each level. At each level, tasks are decomposed into sequential subtasks, to be performed by cooperating sets of subordinate agents. At each level, signals from sensors are filtered and correlated with spatial and temporal features that are relevant to the control function being implemented at that level.

  14. Real-time model-based vision system for object acquisition and tracking

    NASA Technical Reports Server (NTRS)

    Wilcox, Brian; Gennery, Donald B.; Bon, Bruce; Litwin, Todd

    1987-01-01

    A machine vision system is described which is designed to acquire and track polyhedral objects moving and rotating in space by means of two or more cameras, programmable image-processing hardware, and a general-purpose computer for high-level functions. The image-processing hardware is capable of performing a large variety of operations on images and on image-like arrays of data. Acquisition utilizes image locations and velocities of the features extracted by the image-processing hardware to determine the three-dimensional position, orientation, velocity, and angular velocity of the object. Tracking correlates edges detected in the current image with edge locations predicted from an internal model of the object and its motion, continually updating velocity information to predict where edges should appear in future frames. With some 10 frames processed per second, real-time tracking is possible.

  15. Providing Real-time Sea Ice Modeling Support to the U.S. Coast Guard

    NASA Astrophysics Data System (ADS)

    Allard, Richard; Dykes, James; Hebert, David; Posey, Pamela; Rogers, Erick; Wallcraft, Alan; Phelps, Michael; Smedstad, Ole Martin; Wang, Shouping; Geiszler, Dan

    2016-04-01

    The Naval Research Laboratory (NRL) supported the U.S. Coast Guard Research Development Center (RDC) through a demonstration project during the summer and autumn of 2015. Specifically, a modeling system composed of a mesoscale atmospheric model, regional sea ice model, and regional wave model were loosely coupled to provide real-time 72-hr forecasts of environmental conditions for the Beaufort/Chukchi Seas. The system components included a 2-km regional Community Ice CodE (CICE) sea ice model, 15-km Coupled Ocean Atmosphere Mesoscale Prediction System (COAMPS) atmospheric model, and a 5-km regional WAVEWATCH III wave model. The wave model utilized modeled sea ice concentration fields to incorporate the effects of sea ice on waves. The other modeling components assimilated atmosphere, ocean, and ice observations available from satellite and in situ sources. The modeling system generated daily 72-hr forecasts of synoptic weather (including visibility), ice drift, ice thickness, ice concentration and ice strength for missions within the economic exclusion zone off the coast of Alaska and a transit to the North Pole in support of the National Science Foundation GEOTRACES cruise. Model forecasts graphics were shared on a common web page with selected graphical products made available via ftp for bandwidth limited users. Model ice thickness and ice drift show very good agreement compared with Cold Regions Research and Engineering Laboratory (CRREL) Ice Mass Balance buoys. This demonstration served as a precursor to a fully coupled atmosphere-ocean-wave-ice modeling system under development. National Ice Center (NIC) analysts used these model data products (CICE and COAMPS) along with other existing model and satellite data to produce the predicted 48-hr position of the ice edge. The NIC served as a liaison with the RDC and NRL to provide feedback on the model predictions. This evaluation provides a baseline analysis of the current models for future comparison studies

  16. Improving Computational Efficiency of Model Predictive Control Genetic Algorithms for Real-Time Decision Support

    NASA Astrophysics Data System (ADS)

    Minsker, B. S.; Zimmer, A. L.; Ostfeld, A.; Schmidt, A.

    2014-12-01

    Enabling real-time decision support, particularly under conditions of uncertainty, requires computationally efficient algorithms that can rapidly generate recommendations. In this paper, a suite of model predictive control (MPC) genetic algorithms are developed and tested offline to explore their value for reducing CSOs during real-time use in a deep-tunnel sewer system. MPC approaches include the micro-GA, the probability-based compact GA, and domain-specific GA methods that reduce the number of decision variable values analyzed within the sewer hydraulic model, thus reducing algorithm search space. Minimum fitness and constraint values achieved by all GA approaches, as well as computational times required to reach the minimum values, are compared to large population sizes with long convergence times. Optimization results for a subset of the Chicago combined sewer system indicate that genetic algorithm variations with coarse decision variable representation, eventually transitioning to the entire range of decision variable values, are most efficient at addressing the CSO control problem. Although diversity-enhancing micro-GAs evaluate a larger search space and exhibit shorter convergence times, these representations do not reach minimum fitness and constraint values. The domain-specific GAs prove to be the most efficient and are used to test CSO sensitivity to energy costs, CSO penalties, and pressurization constraint values. The results show that CSO volumes are highly dependent on the tunnel pressurization constraint, with reductions of 13% to 77% possible with less conservative operational strategies. Because current management practices may not account for varying costs at CSO locations and electricity rate changes in the summer and winter, the sensitivity of the results is evaluated for variable seasonal and diurnal CSO penalty costs and electricity-related system maintenance costs, as well as different sluice gate constraint levels. These findings indicate

  17. Real-time source deformation modeling through GNSS permanent stations at Merapi volcano (Indonesia

    NASA Astrophysics Data System (ADS)

    Beauducel, F.; Nurnaning, A.; Iguchi, M.; Fahmi, A. A.; Nandaka, M. A.; Sumarti, S.; Subandriyo, S.; Metaxian, J. P.

    2014-12-01

    Mt. Merapi (Java, Indonesia) is one of the most active and dangerous volcano in the world. A first GPS repetition network was setup and periodically measured since 1993, allowing detecting a deep magma reservoir, quantifying magma flux in conduit and identifying shallow discontinuities around the former crater (Beauducel and Cornet, 1999;Beauducel et al., 2000, 2006). After the 2010 centennial eruption, when this network was almost completely destroyed, Indonesian and Japanese teams installed a new continuous GPS network for monitoring purpose (Iguchi et al., 2011), consisting of 3 stations located at the volcano flanks, plus a reference station at the Yogyakarta Observatory (BPPTKG).In the framework of DOMERAPI project (2013-2016) we have completed this network with 5 additional stations, which are located on the summit area and volcano surrounding. The new stations are 1-Hz sampling, GNSS (GPS + GLONASS) receivers, and near real-time data streaming to the Observatory. An automatic processing has been developed and included in the WEBOBS system (Beauducel et al., 2010) based on GIPSY software computing precise daily moving solutions every hour, and for different time scales (2 months, 1 and 5 years), time series and velocity vectors. A real-time source modeling estimation has also been implemented. It uses the depth-varying point source solution (Mogi, 1958; Williams and Wadge, 1998) in a systematic inverse problem model exploration that displays location, volume variation and 3-D probability map.The operational system should be able to better detect and estimate the location and volume variations of possible magma sources, and to follow magma transfer towards the surface. This should help monitoring and contribute to decision making during future unrest or eruption.

  18. Aggregate modeling of fast-acting demand response and control under real-time pricing

    DOE PAGES

    Chassin, David P.; Rondeau, Daniel

    2016-08-24

    This paper develops and assesses the performance of a short-term demand response (DR) model for utility load control with applications to resource planning and control design. Long term response models tend to underestimate short-term demand response when induced by prices. This has two important consequences. First, planning studies tend to undervalue DR and often overlook its benefits in utility demand management program development. Second, when DR is not overlooked, the open-loop DR control gain estimate may be too low. This can result in overuse of load resources, control instability and excessive price volatility. Our objective is therefore to develop amore » more accurate and better performing short-term demand response model. We construct the model from first principles about the nature of thermostatic load control and show that the resulting formulation corresponds exactly to the Random Utility Model employed in economics to study consumer choice. The model is tested against empirical data collected from field demonstration projects and is shown to perform better than alternative models commonly used to forecast demand in normal operating conditions. Finally, the results suggest that (1) existing utility tariffs appear to be inadequate to incentivize demand response, particularly in the presence of high renewables, and (2) existing load control systems run the risk of becoming unstable if utilities close the loop on real-time prices.« less

  19. Aggregate modeling of fast-acting demand response and control under real-time pricing

    SciTech Connect

    Chassin, David P.; Rondeau, Daniel

    2016-08-24

    This paper develops and assesses the performance of a short-term demand response (DR) model for utility load control with applications to resource planning and control design. Long term response models tend to underestimate short-term demand response when induced by prices. This has two important consequences. First, planning studies tend to undervalue DR and often overlook its benefits in utility demand management program development. Second, when DR is not overlooked, the open-loop DR control gain estimate may be too low. This can result in overuse of load resources, control instability and excessive price volatility. Our objective is therefore to develop a more accurate and better performing short-term demand response model. We construct the model from first principles about the nature of thermostatic load control and show that the resulting formulation corresponds exactly to the Random Utility Model employed in economics to study consumer choice. The model is tested against empirical data collected from field demonstration projects and is shown to perform better than alternative models commonly used to forecast demand in normal operating conditions. Finally, the results suggest that (1) existing utility tariffs appear to be inadequate to incentivize demand response, particularly in the presence of high renewables, and (2) existing load control systems run the risk of becoming unstable if utilities close the loop on real-time prices.

  20. Techniques for increasing the update rate of real-time dynamic computer graphic displays

    NASA Technical Reports Server (NTRS)

    Kahlbaum, W. M., Jr.

    1986-01-01

    This paper describes several techniques which may be used to increase the animation update rate of real-time computer raster graphic displays. The techniques were developed on the ADAGE RDS 3000 graphic system in support of the Advanced Concepts Simulator at the NASA Langley Research Center. The first technique involves pre-processing of the next animation frame while the previous one is being erased from the screen memory. The second technique involves the use of a parallel processor, the AGG4, for high speed character generation. The description of the AGG4 includes the Barrel Shifter which is a part of the hardware and is the key to the high speed character rendition. The final result of this total effort was a four fold increase in the update rate of an existing primary flight display from 4 to 16 frames per second.

  1. Real time wave forecasting using wind time history and numerical model

    NASA Astrophysics Data System (ADS)

    Jain, Pooja; Deo, M. C.; Latha, G.; Rajendran, V.

    Operational activities in the ocean like planning for structural repairs or fishing expeditions require real time prediction of waves over typical time duration of say a few hours. Such predictions can be made by using a numerical model or a time series model employing continuously recorded waves. This paper presents another option to do so and it is based on a different time series approach in which the input is in the form of preceding wind speed and wind direction observations. This would be useful for those stations where the costly wave buoys are not deployed and instead only meteorological buoys measuring wind are moored. The technique employs alternative artificial intelligence approaches of an artificial neural network (ANN), genetic programming (GP) and model tree (MT) to carry out the time series modeling of wind to obtain waves. Wind observations at four offshore sites along the east coast of India were used. For calibration purpose the wave data was generated using a numerical model. The predicted waves obtained using the proposed time series models when compared with the numerically generated waves showed good resemblance in terms of the selected error criteria. Large differences across the chosen techniques of ANN, GP, MT were not noticed. Wave hindcasting at the same time step and the predictions over shorter lead times were better than the predictions over longer lead times. The proposed method is a cost effective and convenient option when a site-specific information is desired.

  2. Real time forecasts through physical and stochastic models of earthquake clustering

    NASA Astrophysics Data System (ADS)

    Murru, M.; Console, R.; Catalli, F.; Falcone, G.

    2005-12-01

    The phenomenon of earthquake interaction has become a popular subject of study because it can shed light on the physical processes leading to earthquakes, and because it has a potential value for short-term earthquake forecast and hazard mitigation. In this study we start from a purely stochastic approach known as the so-called epidemic model (ETAS) introduced by Ogata in 1988 and its variations. Then we build up an approach by which this model and the rate-and-state constitutive law introduced by Dieterich in the `90s have been merged in a single algorithm and statistically tested. Tests on real seismicity and comparison with a plain time-independent Poissonian model through likelihood-based methods have reliably proved their validity. The models are suitable for real-time forecast of the seismic activity. In the context of the low-magnitude Italian seismicity recorded from 1987 to 2005, the new model incorporating the physical concept of the rate-and-state theory performs not better than the purely stochastic model. Nevertheless, it has the advantage of needing a smaller number of free parameters and providing new interesting insights on the physics of the seismogenic process.

  3. Real-time observation of dynamic floor motion of the KEKB injector linac with a laser-based alignment system

    NASA Astrophysics Data System (ADS)

    Suwada, T.; Enomoto, Y.; Kakihara, K.; Mikawa, K.; Higo, T.

    2017-03-01

    A new remote-controllable sensing system for a laser-based alignment system is in development to measure slow dynamic displacements of the tunnel floor in real time at the KEKB injector linac. Although the injector linac had initially been aligned with a laser-based alignment system, we have found that, based on recent real-time observations, the transverse displacements of the tunnel floor to the laser axis caused by dynamic ground motion are not negligibly small compared with the required alignment tolerance, in terms of the straightness of the beam line. Based on spatial and temporal cross-correlation analyses performed using displacement vectors from data recorded during a nearly eight-month period, it was found that the tunnel floor moves coherently in space and time domains over the entire length of the linac on average over long periods of time, while the cross-correlation function varies irregularly and complexly over shorter periods of time. This report describes in detail the basic design, experimental results, and present status of the new remote-sensing system for real-time alignment observations at the KEKB injector linac.

  4. Real-time dynamic calibration of a tunable frequency laser source using a Fabry-Pérot interferometer

    SciTech Connect

    Mandula, Gábor Kis, Zsolt; Lengyel, Krisztián

    2015-12-15

    We report on a method for real-time dynamic calibration of a tunable external cavity diode laser by using a partially mode-matched plano-concave Fabry-Pérot interferometer in reflection geometry. Wide range laser frequency scanning is carried out by piezo-driven tilting of a diffractive grating playing the role of a frequency selective mirror in the laser cavity. The grating tilting system has a considerable mechanical inertness, so static laser frequency calibration leads to false results. The proposed real-time dynamic calibration based on the identification of primary- and Gouy-effect type secondary interference peaks with known frequency and temporal history can be used for a wide scanning range (from 0.2 GHz to more than 1 GHz). A concave spherical mirror with a radius of R = 100 cm and a plain 1% transmitting mirror was used as a Fabry-Pérot interferometer with various resonator lengths to investigate and demonstrate real-time calibration procedures for two kinds of laser frequency scanning functions.

  5. High dynamic range adaptive real-time smart camera: an overview of the HDR-ARTiST project

    NASA Astrophysics Data System (ADS)

    Lapray, Pierre-Jean; Heyrman, Barthélémy; Ginhac, Dominique

    2015-04-01

    Standard cameras capture only a fraction of the information that is visible to the human visual system. This is specifically true for natural scenes including areas of low and high illumination due to transitions between sunlit and shaded areas. When capturing such a scene, many cameras are unable to store the full Dynamic Range (DR) resulting in low quality video where details are concealed in shadows or washed out by sunlight. The imaging technique that can overcome this problem is called HDR (High Dynamic Range) imaging. This paper describes a complete smart camera built around a standard off-the-shelf LDR (Low Dynamic Range) sensor and a Virtex-6 FPGA board. This smart camera called HDR-ARtiSt (High Dynamic Range Adaptive Real-time Smart camera) is able to produce a real-time HDR live video color stream by recording and combining multiple acquisitions of the same scene while varying the exposure time. This technique appears as one of the most appropriate and cheapest solution to enhance the dynamic range of real-life environments. HDR-ARtiSt embeds real-time multiple captures, HDR processing, data display and transfer of a HDR color video for a full sensor resolution (1280 1024 pixels) at 60 frames per second. The main contributions of this work are: (1) Multiple Exposure Control (MEC) dedicated to the smart image capture with alternating three exposure times that are dynamically evaluated from frame to frame, (2) Multi-streaming Memory Management Unit (MMMU) dedicated to the memory read/write operations of the three parallel video streams, corresponding to the different exposure times, (3) HRD creating by combining the video streams using a specific hardware version of the Devebecs technique, and (4) Global Tone Mapping (GTM) of the HDR scene for display on a standard LCD monitor.

  6. A feedback control system for real-time formant estimation. I--Static and dynamic analysis for sinusoidal input signals.

    PubMed

    Zierhofer, C M; Hochmair, E S

    1993-09-01

    This paper presents a novel analog scheme suitable for the real-time estimation of formant frequencies. Formant tracking is based on a feedback technique which uses both the amplitude and phase characteristics of two stagger-tuned bandpass filters to give an improved dynamic behavior. The implementation of the system requires a small number of components, and is practical for low-power applications. An analysis of the static and dynamic behavior is given for sinusoidal input signals. The transient response is independent of the amplitude level of the input signal. The system is designed for second formant detection in a cochlear prosthesis system.

  7. Real-time model based process monitoring of enzymatic biodiesel production.

    PubMed

    Price, Jason; Nordblad, Mathias; Woodley, John M; Huusom, Jakob K

    2015-01-01

    In this contribution we extend our modelling work on the enzymatic production of biodiesel where we demonstrate the application of a Continuous-Discrete Extended Kalman Filter (a state estimator). The state estimator is used to correct for mismatch between the process data and the process model for Fed-batch production of biodiesel. For the three process runs investigated, using a single tuning parameter, qx  = 2 × 10(-2) which represents the uncertainty in the process model, it was possible over the entire course of the reaction to reduce the overall mean and standard deviation of the error between the model and the process data for all of the five measured components (triglycerides, diglycerides, monoglycerides, fatty acid methyl esters, and free fatty acid). The most significant reduction for the three process runs, were for the monoglyceride and free fatty acid concentration. For those components, there was over a ten-fold decrease in the overall mean error for the state estimator prediction compared with the predictions from the pure model simulations. It is also shown that the state estimator can be used as a tool for detection of outliers in the measurement data. For the enzymatic biodiesel process, given the infrequent and sometimes uncertain measurements obtained we see the use of the Continuous-Discrete Extended Kalman Filter as a viable tool for real time process monitoring.

  8. A search for model parsimony in a real time flood forecasting system

    NASA Astrophysics Data System (ADS)

    Grossi, G.; Balistrocchi, M.

    2009-04-01

    As regards the hydrological simulation of flood events, a physically based distributed approach is the most appealing one, especially in those areas where the spatial variability of the soil hydraulic properties as well as of the meteorological forcing cannot be left apart, such as in mountainous regions. On the other hand, dealing with real time flood forecasting systems, less detailed models requiring a minor number of parameters may be more convenient, reducing both the computational costs and the calibration uncertainty. In fact in this case a precise quantification of the entire hydrograph pattern is not necessary, while the expected output of a real time flood forecasting system is just an estimate of the peak discharge, the time to peak and in some cases the flood volume. In this perspective a parsimonious model has to be found in order to increase the efficiency of the system. A suitable case study was identified in the northern Apennines: the Taro river is a right tributary to the Po river and drains about 2000 km2 of mountains, hills and floodplain, equally distributed . The hydrometeorological monitoring of this medium sized watershed is managed by ARPA Emilia Romagna through a dense network of uptodate gauges (about 30 rain gauges and 10 hydrometers). Detailed maps of the surface elevation, land use and soil texture characteristics are also available. Five flood events were recorded by the new monitoring network in the years 2003-2007: during these events the peak discharge was higher than 1000 m3/s, which is actually quite a high value when compared to the mean discharge rate of about 30 m3/s. The rainfall spatial patterns of such storms were analyzed in previous works by means of geostatistical tools and a typical semivariogram was defined, with the aim of establishing a typical storm structure leading to flood events in the Taro river. The available information was implemented into a distributed flood event model with a spatial resolution of 90m

  9. Real-time inversions for finite fault slip models and rupture geometry based on high-rate GPS data

    USGS Publications Warehouse

    Minson, Sarah E.; Murray, Jessica R.; Langbein, John O.; Gomberg, Joan S.

    2015-01-01

    We present an inversion strategy capable of using real-time high-rate GPS data to simultaneously solve for a distributed slip model and fault geometry in real time as a rupture unfolds. We employ Bayesian inference to find the optimal fault geometry and the distribution of possible slip models for that geometry using a simple analytical solution. By adopting an analytical Bayesian approach, we can solve this complex inversion problem (including calculating the uncertainties on our results) in real time. Furthermore, since the joint inversion for distributed slip and fault geometry can be computed in real time, the time required to obtain a source model of the earthquake does not depend on the computational cost. Instead, the time required is controlled by the duration of the rupture and the time required for information to propagate from the source to the receivers. We apply our modeling approach, called Bayesian Evidence-based Fault Orientation and Real-time Earthquake Slip, to the 2011 Tohoku-oki earthquake, 2003 Tokachi-oki earthquake, and a simulated Hayward fault earthquake. In all three cases, the inversion recovers the magnitude, spatial distribution of slip, and fault geometry in real time. Since our inversion relies on static offsets estimated from real-time high-rate GPS data, we also present performance tests of various approaches to estimating quasi-static offsets in real time. We find that the raw high-rate time series are the best data to use for determining the moment magnitude of the event, but slightly smoothing the raw time series helps stabilize the inversion for fault geometry.

  10. Application of a ground based minicomputer system for real time, closed loop control of remotely piloted aircraft models used in stall/spin research

    NASA Technical Reports Server (NTRS)

    Montoya, R. J.; Jai, A. R.

    1979-01-01

    The paper describes a minicomputer-based, real-time closed loop remote control system at NASA Langley outdoor facility which is used to determine the stall/departure/spin characteristics of high-performance aircraft. The experiments are conducted with 15% dynamically scaled, unpowered models that are dropped from 3000 m and ground controlled. The effects of time delays and sampling rates on the stability of the control system and the selection of digital algorithms to meet frequency response and real time constraints are examined. Also described is the implementation of the modular software for the flexible programming of multi-axis control laws.

  11. Real-time classification of humans versus animals using profiling sensors and hidden Markov tree model

    NASA Astrophysics Data System (ADS)

    Hossen, Jakir; Jacobs, Eddie L.; Chari, Srikant

    2015-07-01

    Linear pyroelectric array sensors have enabled useful classifications of objects such as humans and animals to be performed with relatively low-cost hardware in border and perimeter security applications. Ongoing research has sought to improve the performance of these sensors through signal processing algorithms. In the research presented here, we introduce the use of hidden Markov tree (HMT) models for object recognition in images generated by linear pyroelectric sensors. HMTs are trained to statistically model the wavelet features of individual objects through an expectation-maximization learning process. Human versus animal classification for a test object is made by evaluating its wavelet features against the trained HMTs using the maximum-likelihood criterion. The classification performance of this approach is compared to two other techniques; a texture, shape, and spectral component features (TSSF) based classifier and a speeded-up robust feature (SURF) classifier. The evaluation indicates that among the three techniques, the wavelet-based HMT model works well, is robust, and has improved classification performance compared to a SURF-based algorithm in equivalent computation time. When compared to the TSSF-based classifier, the HMT model has a slightly degraded performance but almost an order of magnitude improvement in computation time enabling real-time implementation.

  12. Robust Real-Time Music Transcription with a Compositional Hierarchical Model

    PubMed Central

    Pesek, Matevž; Leonardis, Aleš; Marolt, Matija

    2017-01-01

    The paper presents a new compositional hierarchical model for robust music transcription. Its main features are unsupervised learning of a hierarchical representation of input data, transparency, which enables insights into the learned representation, as well as robustness and speed which make it suitable for real-world and real-time use. The model consists of multiple layers, each composed of a number of parts. The hierarchical nature of the model corresponds well to hierarchical structures in music. The parts in lower layers correspond to low-level concepts (e.g. tone partials), while the parts in higher layers combine lower-level representations into more complex concepts (tones, chords). The layers are learned in an unsupervised manner from music signals. Parts in each layer are compositions of parts from previous layers based on statistical co-occurrences as the driving force of the learning process. In the paper, we present the model’s structure and compare it to other hierarchical approaches in the field of music information retrieval. We evaluate the model’s performance for the multiple fundamental frequency estimation. Finally, we elaborate on extensions of the model towards other music information retrieval tasks. PMID:28046074

  13. Computer optimization techniques for NASA Langley's CSI evolutionary model's real-time control system

    NASA Technical Reports Server (NTRS)

    Elliott, Kenny B.; Ugoletti, Roberto; Sulla, Jeff

    1992-01-01

    The evolution and optimization of a real-time digital control system is presented. The control system is part of a testbed used to perform focused technology research on the interactions of spacecraft platform and instrument controllers with the flexible-body dynamics of the platform and platform appendages. The control system consists of Computer Automated Measurement and Control (CAMAC) standard data acquisition equipment interfaced to a workstation computer. The goal of this work is to optimize the control system's performance to support controls research using controllers with up to 50 states and frame rates above 200 Hz. The original system could support a 16-state controller operating at a rate of 150 Hz. By using simple yet effective software improvements, Input/Output (I/O) latencies and contention problems are reduced or eliminated in the control system. The final configuration can support a 16-state controller operating at 475 Hz. Effectively the control system's performance was increased by a factor of 3.

  14. Improving real-time inflow forecasting into hydropower reservoirs through a complementary modelling framework

    NASA Astrophysics Data System (ADS)

    Gragne, A. S.; Sharma, A.; Mehrotra, R.; Alfredsen, K.

    2015-08-01

    Accuracy of reservoir inflow forecasts is instrumental for maximizing the value of water resources and benefits gained through hydropower generation. Improving hourly reservoir inflow forecasts over a 24 h lead time is considered within the day-ahead (Elspot) market of the Nordic exchange market. A complementary modelling framework presents an approach for improving real-time forecasting without needing to modify the pre-existing forecasting model, but instead formulating an independent additive or complementary model that captures the structure the existing operational model may be missing. We present here the application of this principle for issuing improved hourly inflow forecasts into hydropower reservoirs over extended lead times, and the parameter estimation procedure reformulated to deal with bias, persistence and heteroscedasticity. The procedure presented comprises an error model added on top of an unalterable constant parameter conceptual model. This procedure is applied in the 207 km2 Krinsvatn catchment in central Norway. The structure of the error model is established based on attributes of the residual time series from the conceptual model. Besides improving forecast skills of operational models, the approach estimates the uncertainty in the complementary model structure and produces probabilistic inflow forecasts that entrain suitable information for reducing uncertainty in the decision-making processes in hydropower systems operation. Deterministic and probabilistic evaluations revealed an overall significant improvement in forecast accuracy for lead times up to 17 h. Evaluation of the percentage of observations bracketed in the forecasted 95 % confidence interval indicated that the degree of success in containing 95 % of the observations varies across seasons and hydrologic years.

  15. Real-time filtering and detection of dynamics for compression of HDTV

    NASA Technical Reports Server (NTRS)

    Sauer, Ken D.; Bauer, Peter

    1991-01-01

    The preprocessing of video sequences for data compressing is discussed. The end goal associated with this is a compression system for HDTV capable of transmitting perceptually lossless sequences at under one bit per pixel. Two subtopics were emphasized to prepare the video signal for more efficient coding: (1) nonlinear filtering to remove noise and shape the signal spectrum to take advantage of insensitivities of human viewers; and (2) segmentation of each frame into temporally dynamic/static regions for conditional frame replenishment. The latter technique operates best under the assumption that the sequence can be modelled as a superposition of active foreground and static background. The considerations were restricted to monochrome data, since it was expected to use the standard luminance/chrominance decomposition, which concentrates most of the bandwidth requirements in the luminance. Similar methods may be applied to the two chrominance signals.

  16. Hydraulic Modeling and Evolutionary Optimization for Enhanced Real-Time Decision Support of Combined Sewer Overflows

    NASA Astrophysics Data System (ADS)

    Zimmer, A. L.; Minsker, B. S.; Schmidt, A. R.; Ostfeld, A.

    2011-12-01

    Real-time mitigation of combined sewer overflows (CSOs) requires evaluation of multiple operational strategies during rapidly changing rainfall events. Simulation models for hydraulically complex systems can effectively provide decision support for short time intervals when coupled with efficient optimization. This work seeks to reduce CSOs for a test case roughly based on the North Branch of the Chicago Tunnel and Reservoir Plan (TARP), which is operated by the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC). The North Branch tunnel flows to a junction with the main TARP system. The Chicago combined sewer system alleviates potential CSOs by directing high interceptor flows through sluice gates and dropshafts to a deep tunnel. Decision variables to control CSOs consist of sluice gate positions that control water flow to the tunnel as well as a treatment plant pumping rate that lowers interceptor water levels. A physics-based numerical model is used to simulate the hydraulic effects of changes in the decision variables. The numerical model is step-wise steady and conserves water mass and momentum at each time step by iterating through a series of look-up tables. The look-up tables are constructed offline to avoid extensive real-time calculations, and describe conduit storage and water elevations as a function of flow. A genetic algorithm (GA) is used to minimize CSOs at each time interval within a moving horizon framework. Decision variables are coded at 15-minute increments and GA solutions are two hours in duration. At each 15-minute interval, the algorithm identifies a good solution for a two-hour rainfall forecast. Three GA modifications help reduce optimization time. The first adjustment reduces the search alphabet by eliminating sluice gate positions that do not influence overflow volume. The second GA retains knowledge of the best decision at the previous interval by shifting the genes in the best previous sequence to initialize search at

  17. Model Integration for Real-Time Flood Forecasting Inundation Mapping for Nashville Tributaries

    NASA Astrophysics Data System (ADS)

    Charley, W.; Moran, B.; LaRosa, J.

    2012-12-01

    In May of 2010, between 14 and 19 inches of rain fell on the Nashville metro area in two days, quickly overwhelming tributaries to the Cumberland River and causing wide-spread, serious flooding. Tractor-trailers and houses were seen floating down Mill Creek, a primary tributary in the south eastern area of Nashville. Twenty-six people died and over 2 billion dollars in damage occurred as a result of the flood. Since that time, several other significant rainfall events have occurred in the area. Emergency responders were unable to deliver aid or preventive measures to areas under threat of flooding (or under water) in time to reduce damages because they could not identify those areas far enough in advance of the floods. Nashville Metro Water, the National Weather Service, the US Geological Survey and the US Army Corps of Engineers established a joint venture to seek ways to better forecast short-term flood events in the region. One component of this effort was a pilot project to compute and display real time inundation maps for Mill Creek, a 108 square-mile basin to the south east of Nashville. HEC-RTS (Real-Time Simulation) was used to assimilate and integrate the hydrologic model HEC-HMS with the hydraulics model HEC-RAS and the inundation mapping program HEC-RAS Mapper. The USGS, along with the other agencies, installed additional precipitation and flow/stage gages in the area. Measurements are recorded every 5-30 minutes and are posted on the USGS NWIS database, which are downloaded by HEC-RTS. Using this data in combination with QPFs (Quantitative Precipitation Forecasts) from the NWS, HEC-RTS applies HEC-HMS and HEC-RAS to estimate current and forecast stage hydrographs. The peak stages are read by HEC-RAS Mapper to compute inundation depths for 6 by 6 foot grid cells. HEC-RTS displays the inundation on a high resolution MrSid aerial photo, along with subbasin boundary, street and various other layers. When a user zooms in and "mouses" over a cell, the

  18. Earthquake and failure forecasting in real-time: A Forecasting Model Testing Centre

    NASA Astrophysics Data System (ADS)

    Filgueira, Rosa; Atkinson, Malcolm; Bell, Andrew; Main, Ian; Boon, Steven; Meredith, Philip

    2013-04-01

    Across Europe there are a large number of rock deformation laboratories, each of which runs many experiments. Similarly there are a large number of theoretical rock physicists who develop constitutive and computational models both for rock deformation and changes in geophysical properties. Here we consider how to open up opportunities for sharing experimental data in a way that is integrated with multiple hypothesis testing. We present a prototype for a new forecasting model testing centre based on e-infrastructures for capturing and sharing data and models to accelerate the Rock Physicist (RP) research. This proposal is triggered by our work on data assimilation in the NERC EFFORT (Earthquake and Failure Forecasting in Real Time) project, using data provided by the NERC CREEP 2 experimental project as a test case. EFFORT is a multi-disciplinary collaboration between Geoscientists, Rock Physicists and Computer Scientist. Brittle failure of the crust is likely to play a key role in controlling the timing of a range of geophysical hazards, such as volcanic eruptions, yet the predictability of brittle failure is unknown. Our aim is to provide a facility for developing and testing models to forecast brittle failure in experimental and natural data. Model testing is performed in real-time, verifiably prospective mode, in order to avoid selection biases that are possible in retrospective analyses. The project will ultimately quantify the predictability of brittle failure, and how this predictability scales from simple, controlled laboratory conditions to the complex, uncontrolled real world. Experimental data are collected from controlled laboratory experiments which includes data from the UCL Laboratory and from Creep2 project which will undertake experiments in a deep-sea laboratory. We illustrate the properties of the prototype testing centre by streaming and analysing realistically noisy synthetic data, as an aid to generating and improving testing methodologies in

  19. Real-time radiography

    SciTech Connect

    Bossi, R.H.; Oien, C.T.

    1981-02-26

    Real-time radiography is used for imaging both dynamic events and static objects. Fluorescent screens play an important role in converting radiation to light, which is then observed directly or intensified and detected. The radiographic parameters for real-time radiography are similar to conventional film radiography with special emphasis on statistics and magnification. Direct-viewing fluoroscopy uses the human eye as a detector of fluorescent screen light or the light from an intensifier. Remote-viewing systems replace the human observer with a television camera. The remote-viewing systems have many advantages over the direct-viewing conditions such as safety, image enhancement, and the capability to produce permanent records. This report reviews real-time imaging system parameters and components.

  20. Accessing near real-time data for use in global data assimilation models

    NASA Astrophysics Data System (ADS)

    Schunk, R. W.; Gardner, L. C.; Scherliess, L.; Eccles, V.; Zhu, L.

    2015-12-01

    Data assimilation plays a vital part in real-time specification of the ionosphere/thermosphere/atmosphere system for improving geo-location, communication, raytracing, weather prediction, etc. In order to have the best specifications available, it is necessary to acquire and use all the data available on the Internet. With the limited availability of data in the ionosphere/thermosphere, it is important to have as many sources of data as possible to get a good specification, especially with regard to global simulations. For the ionosphere the use of gps slant TEC, ionosonde, DMSP in-situ, and DMSP UV sensors data has been incorporated into the USU GAIM models. The amount of data, the quality of data, and how the data is chosen for use in the data assimilation models and its impacts on model performance will be discussed. The data available comes from GPS satellites, ionosondes/digisondes, DMSP satellites, and other sporadic sources. Even with all of these sources more data is needed in order to produce improved specifications, and more reliable forecasts.

  1. A Dispersion Model Evaluation Study for Real-Time Application in Complex Terrain.

    NASA Astrophysics Data System (ADS)

    Desiato, F.

    1991-08-01

    A few tracer experiments were carried out in autumn 1984 and summer 1985 at the Lago Brasimone site, on the Appennini Mountains approximately 50 km south of Bologna with the purpose assessing the atmospheric dispersion of pollutants under drainage flow conditions. The three-dimensional transport and diffusion model MATHEW/ADPIC (M/A) has been applied to selected tracer and meteorological data with the aim of assessing the model performance under complex terrain and meteorological conditions, and its sensitivity to input data available in real-time applications. Boundary layer input parameters were derived through standard algorithms based on tethersonde and pilot balloon measurements. Model simulations of the most significant tracer experiments have been assessed by means of several evaluation criteria, and the sensitivity to some input data has been investigated. The results show that if a limited spatial uncertainty in the computed concentration pattern is taken into account, M/A provides a good agreement with observed concentrations. The quality of the results is very sensitive to the presence of wind measurements where the deviation of the flow due to the shape of the valley is observed.

  2. Near Real-Time Probabilistic Damage Diagnosis Using Surrogate Modeling and High Performance Computing

    NASA Technical Reports Server (NTRS)

    Warner, James E.; Zubair, Mohammad; Ranjan, Desh

    2017-01-01

    This work investigates novel approaches to probabilistic damage diagnosis that utilize surrogate modeling and high performance computing (HPC) to achieve substantial computational speedup. Motivated by Digital Twin, a structural health management (SHM) paradigm that integrates vehicle-specific characteristics with continual in-situ damage diagnosis and prognosis, the methods studied herein yield near real-time damage assessments that could enable monitoring of a vehicle's health while it is operating (i.e. online SHM). High-fidelity modeling and uncertainty quantification (UQ), both critical to Digital Twin, are incorporated using finite element method simulations and Bayesian inference, respectively. The crux of the proposed Bayesian diagnosis methods, however, is the reformulation of the numerical sampling algorithms (e.g. Markov chain Monte Carlo) used to generate the resulting probabilistic damage estimates. To this end, three distinct methods are demonstrated for rapid sampling that utilize surrogate modeling and exploit various degrees of parallelism for leveraging HPC. The accuracy and computational efficiency of the methods are compared on the problem of strain-based crack identification in thin plates. While each approach has inherent problem-specific strengths and weaknesses, all approaches are shown to provide accurate probabilistic damage diagnoses and several orders of magnitude computational speedup relative to a baseline Bayesian diagnosis implementation.

  3. Modelling effluent quality based on a real-time optical monitoring of the wastewater treatment process.

    PubMed

    Tomperi, Jani; Koivuranta, Elisa; Kuokkanen, Anna; Leiviskä, Kauko

    2017-01-01

    A novel optical monitoring device was used for imaging an activated sludge process in situ during a period of over one year. In this study, the dependencies between the results of image analysis and the process measurements were studied, and the optical monitoring results were utilized to predict the important quality parameters for the wastewater treatment process efficiency: suspended solids, biological oxygen demand, chemical oxygen demand, total nitrogen and total phosphorous in biologically treated wastewater. The optimal subsets of variables for each model were searched using five variable selection methods. It was shown that online optical analysis results have clear dependencies on some process variables and the purification result. The model based on optical monitoring and process variables from the early stage of the treatment process can be used to predict the levels of important quality parameters, and to show the quality of the biologically treated wastewater hours in advance. This study confirms that the optical monitoring method is a valuable tool for monitoring a wastewater treatment process and receiving new information in real time. Combined with predictive modelling, it has the potential to be used in process control, keeping the process in a stable operating condition and avoiding environmental risks.

  4. Improved Strategies and Optimization of Calibration Models for Real-time PCR Absolute Quantification

    EPA Science Inventory

    Real-time PCR absolute quantification applications rely on the use of standard curves to make estimates of DNA target concentrations in unknown samples. Traditional absolute quantification approaches dictate that a standard curve must accompany each experimental run. However, t...

  5. Electron dynamics in complex environments with real-time time dependent density functional theory in a QM-MM framework.

    PubMed

    Morzan, Uriel N; Ramírez, Francisco F; Oviedo, M Belén; Sánchez, Cristián G; Scherlis, Damián A; Lebrero, Mariano C González

    2014-04-28

    This article presents a time dependent density functional theory (TDDFT) implementation to propagate the Kohn-Sham equations in real time, including the effects of a molecular environment through a Quantum-Mechanics Molecular-Mechanics (QM-MM) hamiltonian. The code delivers an all-electron description employing Gaussian basis functions, and incorporates the Amber force-field in the QM-MM treatment. The most expensive parts of the computation, comprising the commutators between the hamiltonian and the density matrix-required to propagate the electron dynamics-, and the evaluation of the exchange-correlation energy, were migrated to the CUDA platform to run on graphics processing units, which remarkably accelerates the performance of the code. The method was validated by reproducing linear-response TDDFT results for the absorption spectra of several molecular species. Two different schemes were tested to propagate the quantum dynamics: (i) a leap-frog Verlet algorithm, and (ii) the Magnus expansion to first-order. These two approaches were confronted, to find that the Magnus scheme is more efficient by a factor of six in small molecules. Interestingly, the presence of iron was found to seriously limitate the length of the integration time step, due to the high frequencies associated with the core-electrons. This highlights the importance of pseudopotentials to alleviate the cost of the propagation of the inner states when heavy nuclei are present. Finally, the methodology was applied to investigate the shifts induced by the chemical environment on the most intense UV absorption bands of two model systems of general relevance: the formamide molecule in water solution, and the carboxy-heme group in Flavohemoglobin. In both cases, shifts of several nanometers are observed, consistently with the available experimental data.

  6. Real-Time Flood Forecasting System Using Channel Flow Routing Model with Updating by Particle Filter

    NASA Astrophysics Data System (ADS)

    Kudo, R.; Chikamori, H.; Nagai, A.

    2008-12-01

    A real-time flood forecasting system using channel flow routing model was developed for runoff forecasting at water gauged and ungaged points along river channels. The system is based on a flood runoff model composed of upstream part models, tributary part models and downstream part models. The upstream part models and tributary part models are lumped rainfall-runoff models, and the downstream part models consist of a lumped rainfall-runoff model for hillslopes adjacent to a river channel and a kinematic flow routing model for a river channel. The flow forecast of this model is updated by Particle filtering of the downstream part model as well as by the extended Kalman filtering of the upstream part model and the tributary part models. The Particle filtering is a simple and powerful updating algorithm for non-linear and non-gaussian system, so that it can be easily applied to the downstream part model without complicated linearization. The presented flood runoff model has an advantage in simlecity of updating procedure to the grid-based distributed models, which is because of less number of state variables. This system was applied to the Gono-kawa River Basin in Japan, and flood forecasting accuracy of the system with both Particle filtering and extended Kalman filtering and that of the system with only extended Kalman filtering were compared. In this study, water gauging stations in the objective basin were divided into two types of stations, that is, reference stations and verification stations. Reference stations ware regarded as ordinary water gauging stations and observed data at these stations are used for calibration and updating of the model. Verification stations ware considered as ungaged or arbitrary points and observed data at these stations are used not for calibration nor updating but for only evaluation of forecasting accuracy. The result confirms that Particle filtering of the downstream part model improves forecasting accuracy of runoff at

  7. Dynamics of microcystin production and quantification of potentially toxigenic Microcystis sp. using real-time PCR.

    PubMed

    Srivastava, Ankita; Choi, Gang-Guk; Ahn, Chi-Yong; Oh, Hee-Mock; Ravi, Alok Kumar; Asthana, Ravi Kumar

    2012-03-01

    Cyanobacterial blooms in eutrophied water body are generally composed of various genotypes with or without microcystin-producing genes (mcy gene cluster). Thus there is a need for quantification of potent toxin producing strains. The present study aimed at identifying microcystin variants and its producer strains in Durgakund pond, Varanasi, India, based on quantification of cpcBA-IGS and mcyA (condensation domain) genes using real-time PCR and LC-MS. Increase in microcystin concentrations was correlated with increase in mcyA copy number and the level of pigments (chlorophyll a, phycocyanin and carotenoids). Also, selected environmental factors (water temperature, light irradiance, rainfall, pH, N and P) and the concentration of microcystin variants (MC-LR, -RR and -YR) were also assessed in samples during May 2010 to April 2011 to establish the possible correlation among these parameters. Nutrients favored cyanobacterial bloom but it could not be correlated with the levels of microcystin variants and seemed to be geographically specific. Microcystis sp. dominant in the pond comprised potentially toxigenic cells. The ratio of potentially toxigenic Microcystis sp. to that of total Microcystis sp. ranged from 0% to 14%. Such studies paved the way to identify and quantify the most potent microcystin producer in the tropical aquatic body.

  8. Monitoring in real-time focal adhesion protein dynamics in response to a discrete mechanical stimulus.

    PubMed

    von Bilderling, Catalina; Caldarola, Martín; Masip, Martín E; Bragas, Andrea V; Pietrasanta, Lía I

    2017-01-01

    The adhesion of cells to the extracellular matrix is a hierarchical, force-dependent, multistage process that evolves at several temporal scales. An understanding of this complex process requires a precise measurement of forces and its correlation with protein responses in living cells. We present a method to quantitatively assess live cell responses to a local and specific mechanical stimulus. Our approach combines atomic force microscopy with fluorescence imaging. Using this approach, we evaluated the recruitment of adhesion proteins such as vinculin, focal adhesion kinase, paxillin, and zyxin triggered by applying forces in the nN regime to live cells. We observed in real time the development of nascent adhesion sites, evident from the accumulation of early adhesion proteins at the position where the force was applied. We show that the method can be used to quantify the recruitment characteristic times for adhesion proteins in the formation of focal complexes. We also found a spatial remodeling of the mature focal adhesion protein zyxin as a function of the applied force. Our approach allows the study of a variety of complex biological processes involved in cellular mechanotransduction.

  9. Real-Time Manganese Phase Dynamics during Biological and Abiotic Manganese Oxide Reduction.

    PubMed

    Johnson, Jena E; Savalia, Pratixa; Davis, Ryan; Kocar, Benjamin D; Webb, Samuel M; Nealson, Kenneth H; Fischer, Woodward W

    2016-04-19

    Manganese oxides are often highly reactive and easily reduced, both abiotically, by a variety of inorganic chemical species, and biologically during anaerobic respiration by microbes. To evaluate the reaction mechanisms of these different reduction routes and their potential lasting products, we measured the sequence progression of microbial manganese(IV) oxide reduction mediated by chemical species (sulfide and ferrous iron) and the common metal-reducing microbe Shewanella oneidensis MR-1 under several endmember conditions, using synchrotron X-ray spectroscopic measurements complemented by X-ray diffraction and Raman spectroscopy on precipitates collected throughout the reaction. Crystalline or potentially long-lived phases produced in these experiments included manganese(II)-phosphate, manganese(II)-carbonate, and manganese(III)-oxyhydroxides. Major controls on the formation of these discrete phases were alkalinity production and solution conditions such as inorganic carbon and phosphate availability. The formation of a long-lived Mn(III) oxide appears to depend on aqueous Mn(2+) production and the relative proportion of electron donors and electron acceptors in the system. These real-time measurements identify mineralogical products during Mn(IV) oxide reduction, contribute to understanding the mechanism of various Mn(IV) oxide reduction pathways, and assist in interpreting the processes occurring actively in manganese-rich environments and recorded in the geologic record of manganese-rich strata.

  10. USC/JPL GAIM: A Real-Time Global Ionospheric Data Assimilation Model

    NASA Astrophysics Data System (ADS)

    Mandrake, L.; Wilson, B. D.; Hajj, G.; Wang, C.; Pi, X. `; Iijima, B.

    2004-12-01

    We are in the midst of a revolution in ionospheric remote sensing driven by the illuminating powers of ground and space-based GPS receivers, new UV remote sensing satellites, and the advent of data assimilation techniques for space weather. The University of Southern Califronia (USC) and the Jet Propulsion Laboratory (JPL) have jointly developed a Global Assimilative Ionospheric Model (GAIM) to monitor space weather, study storm effects, and provide ionospheric calibration for DoD customers and NASA flight projects. GAIM is a physics-based 3D data assimilation model that uses both 4DVAR and Kalman filter techniques to solve for the ion & electron density state and key drivers such as equatorial electrodynamics, neutral winds, and production terms. GAIM accepts as input ground GPS TEC data from 900+ sites, occultation links from CHAMP, SAC-C, IOX, and the coming COSMIC constellation, UV limb and nadir scans from the TIMED and DMSP satellites, and in situ data from a variety of satellites (C/NOFS & DMSP). GAIM can ingest multiple data sources in real time, updates the 3D electron density grid every 5 minutes, and solves for improved drivers every 1-2 hours. GAIM density retrievals have been validated by comparisons to vertical TEC measurements from TOPEX & JASON, slant TEC measurements from independent GPS sites, density profiles from ionosondes & incoherent scatter radars, and alternative tomographic retrievals. Daily USC/JPL GAIM runs have been operational since March 2003 using 100-200 ground GPS sites as input and TOPEX/JASON and ionosondes for daily validation. A prototype real-time GAIM system has been running since May 2004. RT GAIM ingests TEC data from 77+ streaming GPS sites every 5 minutes, adds more TEC for better global coverage every hour from hourly GPS sites, and updates the ionospheric state every 5 minutes using the Kalman filter. We plan to add TEC links from COSMIC occultations and UV radiance data from the DMSP satellites, when they become

  11. Towards real-time change detection in videos based on existing 3D models

    NASA Astrophysics Data System (ADS)

    Ruf, Boitumelo; Schuchert, Tobias

    2016-10-01

    Image based change detection is of great importance for security applications, such as surveillance and reconnaissance, in order to find new, modified or removed objects. Such change detection can generally be performed by co-registration and comparison of two or more images. However, existing 3d objects, such as buildings, may lead to parallax artifacts in case of inaccurate or missing 3d information, which may distort the results in the image comparison process, especially when the images are acquired from aerial platforms like small unmanned aerial vehicles (UAVs). Furthermore, considering only intensity information may lead to failures in detection of changes in the 3d structure of objects. To overcome this problem, we present an approach that uses Structure-from-Motion (SfM) to compute depth information, with which a 3d change detection can be performed against an existing 3d model. Our approach is capable of the change detection in real-time. We use the input frames with the corresponding camera poses to compute dense depth maps by an image-based depth estimation algorithm. Additionally we synthesize a second set of depth maps, by rendering the existing 3d model from the same camera poses as those of the image-based depth map. The actual change detection is performed by comparing the two sets of depth maps with each other. Our method is evaluated on synthetic test data with corresponding ground truth as well as on real image test data.

  12. Gaussian Cubes: Real-Time Modeling for Visual Exploration of Large Multidimensional Datasets.

    PubMed

    Wang, Zhe; Ferreira, Nivan; Wei, Youhao; Bhaskar, Aarthy Sankari; Scheidegger, Carlos

    2017-01-01

    Recently proposed techniques have finally made it possible for analysts to interactively explore very large datasets in real time. However powerful, the class of analyses these systems enable is somewhat limited: specifically, one can only quickly obtain plots such as histograms and heatmaps. In this paper, we contribute Gaussian Cubes, which significantly improves on state-of-the-art systems by providing interactive modeling capabilities, which include but are not limited to linear least squares and principal components analysis (PCA). The fundamental insight in Gaussian Cubes is that instead of precomputing counts of many data subsets (as state-of-the-art systems do), Gaussian Cubes precomputes the best multivariate Gaussian for the respective data subsets. As an example, Gaussian Cubes can fit hundreds of models over millions of data points in well under a second, enabling novel types of visual exploration of such large datasets. We present three case studies that highlight the visualization and analysis capabilities in Gaussian Cubes, using earthquake safety simulations, astronomical catalogs, and transportation statistics. The dataset sizes range around one hundred million elements and 5 to 10 dimensions. We present extensive performance results, a discussion of the limitations in Gaussian Cubes, and future research directions.

  13. Toward real-time three-dimensional mapping of surficial aquifers using a hybrid modeling approach

    NASA Astrophysics Data System (ADS)

    Friedel, Michael J.; Esfahani, Akbar; Iwashita, Fabio

    2016-02-01

    A hybrid modeling approach is proposed for near real-time three-dimensional (3D) mapping of surficial aquifers. First, airborne frequency-domain electromagnetic (FDEM) measurements are numerically inverted to obtain subsurface resistivities. Second, a machine-learning (ML) algorithm is trained using the FDEM measurements and inverted resistivity profiles, and borehole geophysical and hydrogeologic data. Third, the trained ML algorithm is used together with independent FDEM measurements to map the spatial distribution of the aquifer system. Efficacy of the hybrid approach is demonstrated for mapping a heterogeneous surficial aquifer and confining unit in northwestern Nebraska, USA. For this case, independent performance testing reveals that aquifer mapping is unbiased with a strong correlation (0.94) among numerically inverted and ML-estimated binary (clay-silt or sand-gravel) layer resistivities (5-20 ohm-m or 21-5,000 ohm-m), and an intermediate correlation (0.74) for heterogeneous (clay, silt, sand, gravel) layer resistivities (5-5,000 ohm-m). Reduced correlation for the heterogeneous model is attributed to over-estimating the under-sampled high-resistivity gravels (about 0.5 % of the training data), and when removed the correlation increases (0.87). Independent analysis of the numerically inverted and ML-estimated resistivities finds that the hybrid procedure preserves both univariate and spatial statistics for each layer. Following training, the algorithms can map 3D surficial aquifers as fast as leveled FDEM measurements are presented to the ML network.

  14. Model Estimation and Selection towardsUnconstrained Real-Time Tracking and Mapping.

    PubMed

    Gauglitz, Steffen; Sweeney, Chris; Ventura, Jonathan; Turk, Matthew; Höllerer, Tobias

    2014-06-01

    We present an approach and prototype implementation to initialization-free real-time tracking and mapping that supports any type of camera motion in 3D environments, that is, parallax-inducing as well as rotation-only motions. Our approach effectively behaves like a keyframe-based Simultaneous Localization and Mapping system or a panorama tracking and mapping system, depending on the camera movement. It seamlessly switches between the two modes and is thus able to track and map through arbitrary sequences of parallax-inducing and rotation-only camera movements. The system integrates both model-based and model-free tracking, automatically choosing between the two depending on the situation, and subsequently uses the "Geometric Robust Information Criterion" to decide whether the current camera motion can best be represented as a parallax-inducing motion or a rotation-only motion. It continues to collect and map data after tracking failure by creating separate tracks which are later merged if they are found to overlap. This is in contrast to most existing tracking and mapping systems, which suspend tracking and mapping and thus discard valuable data until relocalization with respect to the initial map is successful. We tested our prototype implementation on a variety of video sequences, successfully tracking through different camera motions and fully automatically building combinations of panoramas and 3D structure.

  15. Real-time scattered light dark-field microscopic imaging of the dynamic degradation process of sodium dimethyldithiocarbamate

    NASA Astrophysics Data System (ADS)

    Lei, Gang; Gao, Peng Fei; Liu, Hui; Huang, Cheng Zhi

    2015-12-01

    Single nanoparticle analysis (SNA) technique with the aid of a dark-field microscopic imaging (iDFM) technique has attracted wide attention owing to its high sensitivity. Considering that the degradation of pesticides can bring about serious problems in food and the environment, and that the real-time monitoring of the dynamic degradation process of pesticides can help understand and define their degradation mechanisms, herein we real-time monitored the decomposition dynamics of sodium dimethyldithiocarbamate (NaDDC) under neutral and alkaline conditions by imaging single silver nanoparticles (AgNPs) under a dark-field microscope (DFM); the localized surface plasmon resonance (LSPR) scattering signals were measured at a single nanoparticle level. As a result, the chemical mechanism of the degradation of NaDDC under neutral and alkaline conditions was proposed, and the inhibition effects of metal ions including Zn(ii) and Cu(ii) were investigated in order to understand the decomposition process in different environments. It was found that Cu(ii) forms the most stable complex with NaDDC with a stoichiometric ratio of 1 : 2, which greatly reduces the toxicity.Single nanoparticle analysis (SNA) technique with the aid of a dark-field microscopic imaging (iDFM) technique has attracted wide attention owing to its high sensitivity. Considering that the degradation of pesticides can bring about serious problems in food and the environment, and that the real-time monitoring of the dynamic degradation process of pesticides can help understand and define their degradation mechanisms, herein we real-time monitored the decomposition dynamics of sodium dimethyldithiocarbamate (NaDDC) under neutral and alkaline conditions by imaging single silver nanoparticles (AgNPs) under a dark-field microscope (DFM); the localized surface plasmon resonance (LSPR) scattering signals were measured at a single nanoparticle level. As a result, the chemical mechanism of the degradation of Na

  16. Demand response-enabled model predictive HVAC load control in buildings using real-time electricity pricing

    NASA Astrophysics Data System (ADS)

    Avci, Mesut

    A practical cost and energy efficient model predictive control (MPC) strategy is proposed for HVAC load control under dynamic real-time electricity pricing. The MPC strategy is built based on a proposed model that jointly minimizes the total energy consumption and hence, cost of electricity for the user, and the deviation of the inside temperature from the consumer's preference. An algorithm that assigns temperature set-points (reference temperatures) to price ranges based on the consumer's discomfort tolerance index is developed. A practical parameter prediction model is also designed for mapping between the HVAC load and the inside temperature. The prediction model and the produced temperature set-points are integrated as inputs into the MPC controller, which is then used to generate signal actions for the AC unit. To investigate and demonstrate the effectiveness of the proposed approach, a simulation based experimental analysis is presented using real-life pricing data. An actual prototype for the proposed HVAC load control strategy is then built and a series of prototype experiments are conducted similar to the simulation studies. The experiments reveal that the MPC strategy can lead to significant reductions in overall energy consumption and cost savings for the consumer. Results suggest that by providing an efficient response strategy for the consumers, the proposed MPC strategy can enable the utility providers to adopt efficient demand management policies using real-time pricing. Finally, a cost-benefit analysis is performed to display the economic feasibility of implementing such a controller as part of a building energy management system, and the payback period is identified considering cost of prototype build and cost savings to help the adoption of this controller in the building HVAC control industry.

  17. Assimilation of real-time riometer measurements into models of 30 MHz polar cap absorption

    NASA Astrophysics Data System (ADS)

    Rogers, Neil Christopher; Honary, Farideh

    2015-04-01

    Space weather events may adversely affect high frequency (HF) radio propagation, hence the ability to provide nowcasting and forecasting of HF radio absorption is key for industries that rely on HF communications. This paper presents methods of assimilating 30 MHz radio absorption measurements into two types of ionospheric polar cap absorption (PCA) model to improve their performance as nowcasting tools. Type 1 models calculate absorption as m times the square root of the flux of solar protons above an energy threshold, Et. Measurements from 14 riometers during 94 solar proton events (1995-2010) are assimilated by optimising the day and night values of m by linear regression. Further non-linear optimisations are demonstrated in which parameters such as Et are also optimised and additional terms characterise local time and seasonal variations. These optimisations reduce RMS errors by up to 36%. Type 2 models incorporate altitude profiles of electron and neutral densities and electron temperatures. Here the scale height of the effective recombination coefficient profile in the D-region is optimised by regression. Furthermore, two published models of the rigidity cut-off latitude (CL) are assessed by comparison with riometer measurements. A small improvement in performance is observed by introducing a 3-h lag in the geomagnetic index Kp in the CL models. Assimilating data from a single riometer in the polar cap reduces RMS errors below 1 dB with less than 0.2 dB bias. However, many high-latitude riometers now provide absorption measurements in near-real time and we demonstrate how these data may be assimilated by fitting a low-order spherical harmonic function to both the measurements and a PCA model with optimised parameters.

  18. Real-Time Dynamic Atomic Spectroscopy Using Electro-Optic Frequency Combs

    NASA Astrophysics Data System (ADS)

    Hébert, Nicolas Bourbeau; Michaud-Belleau, Vincent; Perrella, Christopher; Truong, Gar-Wing; Anstie, James D.; Stace, Thomas M.; Genest, Jérôme; Luiten, Andre N.

    2016-10-01

    Spectroscopy is a key technology for both fundamental and applied science. A long-held desire has been the development of a means to continuously acquire broadband spectral data with simultaneous high time and frequency resolution. Frequency-comb technology can open this door: here, we use a spectroscopic technique based on an electro-optic comb to make continuous observations of cesium vapor across a 3.2-GHz spectral bandwidth with a 2-μ s time resolution and with 10-MHz frequency sampling. We use a rapidly switched pump laser to burn narrow features into the spectral line and study the response to this step perturbation. This examination allows us to see a number of unexpected effects, including the temporal evolution of the bandwidth, the amplitude, and the frequency of these burnt features. We also report on the previously unobserved effect of radiation reabsorption, which slowly produces a broad pedestal of perturbation around each feature. We present models that can explain these dynamical effects.

  19. V/STOL tilt rotor study. Volume 5: A mathematical model for real time flight simulation of the Bell model 301 tilt rotor research aircraft

    NASA Technical Reports Server (NTRS)

    Harendra, P. B.; Joglekar, M. J.; Gaffey, T. M.; Marr, R. L.

    1973-01-01

    A mathematical model for real-time flight simulation of a tilt rotor research aircraft was developed. The mathematical model was used to support the aircraft design, pilot training, and proof-of-concept aspects of the development program. The structure of the mathematical model is indicated by a block diagram. The mathematical model differs from that for a conventional fixed wing aircraft principally in the added requirement to represent the dynamics and aerodynamics of the rotors, the interaction of the rotor wake with the airframe, and the rotor control and drive systems. The constraints imposed on the mathematical model are defined.

  20. WE-G-18C-08: Real Time Tumor Imaging Using a Novel Dynamic Keyhole MRI Reconstruction Technique

    SciTech Connect

    Lee, D; Pollock, S; Whelan, B; Keall, P; Greer, P; Kim, T

    2014-06-15

    Purpose: To test the hypothesis that the novel Dynamic Keyhole MRI reconstruction technique can accelerate image acquisition whilst maintaining high image quality for lung cancer patients. Methods: 18 MRI datasets from 5 lung cancer patients were acquired using a 3T MRI scanner. These datasets were retrospectively reconstructed using (A) The novel Dynamic Keyhole technique, (B) The conventional keyhole technique and (C) the conventional zero filling technique. The dynamic keyhole technique in MRI refers to techniques in which previously acquired k-space data is used to supplement under sampled data obtained in real time. The novel Dynamic Keyhole technique utilizes a previously acquired a library of kspace datasets in conjunction with central k-space datasets acquired in realtime. A simultaneously acquired respiratory signal is utilized to sort, match and combine the two k-space streams with respect to respiratory displacement. Reconstruction performance was quantified by (1) comparing the keyhole size (which corresponds to imaging speed) required to achieve the same image quality, and (2) maintaining a constant keyhole size across the three reconstruction methods to compare the resulting image quality to the ground truth image. Results: (1) The dynamic keyhole method required a mean keyhole size which was 48% smaller than the conventional keyhole technique and 60% smaller than the zero filling technique to achieve the same image quality. This directly corresponds to faster imaging. (2) When a constant keyhole size was utilized, the Dynamic Keyhole technique resulted in the smallest difference of the tumor region compared to the ground truth. Conclusion: The dynamic keyhole is a simple and adaptable technique for clinical applications requiring real-time imaging and tumor monitoring such as MRI guided radiotherapy. Based on the results from this study, the dynamic keyhole method could increase the imaging frequency by a factor of five compared with full k

  1. Ocean-Science Mission Needs: Real-Time AUV Data for Command, Control, and Model Inputs

    NASA Technical Reports Server (NTRS)

    Carder, Kendall L.; Costello, D. K.; Warrior, H.; Langebrake, L. C.; Hou, W.; Patten, J. T.; Kaltenbacher, E.

    2001-01-01

    Predictive models for tides, hydrodynamics, and bio-optical properties affecting the visibility and buoyancy of coastal waters are needed to evaluate the safety of personnel and equipment engaged in maritime operations under potentially hazardous conditions. Predicted currents can be markedly different for two-layer systems affected by terrestrial runoff than for well-mixed conditions because the layering decouples the surface and bottom Ekman layers and rectifies the current response to oscillatory upwelling-and downwelling-favorable winds. Standard ocean models (e.g. Princeton Ocean Model) require initial-and boundary data on the physical and optical properties of the multilayered water column to provide accurate simulations of heat budgets and circulation. Two observational systems are designed to measure vertically structured conditions on the West Florida Shelf (WFS): a tethered buoy network and an autonomous underwater vehicle (AUV) observational system. The AUV system is described with a focus on the observational systems that challenge or limit the communications command and control network for various types of measurement programs. These include vertical oscillatory missions on shelf transects to observe the optical and hydrographic properties of the water column, and bottom-following missions for measuring the bottom albedo. Models of light propagation, absorption, and conversion to heat as well as determination of the buoyancy terms for physical models require these measurements. High data rates associated with video bottom imagery are the most challenging for the real-time, command and control communications system, but they are met through a combination of loss-less and lossy data-compression methods, depending upon the data-rate of the radio links.

  2. A Human Sensor Network Framework in Support of Near Real Time Situational Geophysical Modeling

    NASA Astrophysics Data System (ADS)

    Aulov, O.; Price, A.; Smith, J. A.; Halem, M.

    2013-12-01

    The area of Disaster Management is well established among Federal Agencies such as FEMA, EPA, NOAA and NASA. These agencies have well formulated frameworks for response and mitigation based on near real time satellite and conventional observing networks for assimilation into geophysical models. Forecasts from these models are used to communicate with emergency responders and the general public. More recently, agencies have started using social media to broadcast warnings and alerts to potentially affected communities. In this presentation, we demonstrate the added benefits of mining and assimilating the vast amounts of social media data available from heterogeneous hand held devices and social networks into established operational geophysical modeling frameworks as they apply to the five cornerstones of disaster management - Prevention, Mitigation, Preparedness, Response and Recovery. Often, in situations of extreme events, social media provide the earliest notification of adverse extreme events. However, various forms of social media data also can provide useful geolocated and time stamped in situ observations, complementary to directly sensed conventional observations. We use the concept of a Human Sensor Network where one views social media users as carrying field deployed "sensors" whose posts are the remotely "sensed instrument measurements.' These measurements can act as 'station data' providing the resolution and coverage needed for extreme event specific modeling and validation. Here, we explore the use of social media through the use of a Human Sensor Network (HSN) approach as another data input source for assimilation into geophysical models. Employing the HSN paradigm can provide useful feedback in near real-time, but presents software challenges for rapid access, quality filtering and transforming massive social media data into formats consistent with the operational models. As a use case scenario, we demonstrate the value of HSN for disaster management

  3. Modeling solvation effects in real-space and real-time within density functional approaches.

    PubMed

    Delgado, Alain; Corni, Stefano; Pittalis, Stefano; Rozzi, Carlo Andrea

    2015-10-14

    The Polarizable Continuum Model (PCM) can be used in conjunction with Density Functional Theory (DFT) and its time-dependent extension (TDDFT) to simulate the electronic and optical properties of molecules and nanoparticles immersed in a dielectric environment, typically liquid solvents. In this contribution, we develop a methodology to account for solvation effects in real-space (and real-time) (TD)DFT calculations. The boundary elements method is used to calculate the solvent reaction potential in terms of the apparent charges that spread over the van der Waals solute surface. In a real-space representation, this potential may exhibit a Coulomb singularity at grid points that are close to the cavity surface. We propose a simple approach to regularize such singularity by using a set of spherical Gaussian functions to distribute the apparent charges. We have implemented the proposed method in the Octopus code and present results for the solvation free energies and solvatochromic shifts for a representative set of organic molecules in water.

  4. Double point source W-phase inversion: Real-time implementation and automated model selection

    USGS Publications Warehouse

    Nealy, Jennifer; Hayes, Gavin

    2015-01-01

    Rapid and accurate characterization of an earthquake source is an extremely important and ever evolving field of research. Within this field, source inversion of the W-phase has recently been shown to be an effective technique, which can be efficiently implemented in real-time. An extension to the W-phase source inversion is presented in which two point sources are derived to better characterize complex earthquakes. A single source inversion followed by a double point source inversion with centroid locations fixed at the single source solution location can be efficiently run as part of earthquake monitoring network operational procedures. In order to determine the most appropriate solution, i.e., whether an earthquake is most appropriately described by a single source or a double source, an Akaike information criterion (AIC) test is performed. Analyses of all earthquakes of magnitude 7.5 and greater occurring since January 2000 were performed with extended analyses of the September 29, 2009 magnitude 8.1 Samoa earthquake and the April 19, 2014 magnitude 7.5 Papua New Guinea earthquake. The AIC test is shown to be able to accurately select the most appropriate model and the selected W-phase inversion is shown to yield reliable solutions that match published analyses of the same events.

  5. Double Point Source W-phase Inversion: Real-time Implementation and Automated Model Selection

    NASA Astrophysics Data System (ADS)

    Nealy, J. L.; Hayes, G. P.

    2015-12-01

    Rapid and accurate characterization of an earthquake source is an extremely important and ever-evolving field of research. Within this field, source inversion of the W-phase has recently been shown to be an effective technique, which can be efficiently implemented in real-time. An extension to the W-phase source inversion is presented in which two point sources are derived to better characterize complex earthquakes. A single source inversion followed by a double point source inversion with centroid locations fixed at the single source solution location can be efficiently run as part of earthquake monitoring network operational procedures. In order to determine the most appropriate solution, i.e., whether an earthquake is most appropriately described by a single source or a double source, an Akaike information criterion (AIC) test is performed. Analyses of all earthquakes of magnitude 7.5 and greater occurring since January 2000 were performed with extended analyses of the September 29, 2009 magnitude 8.1 Samoa and the April 19, 2014 magnitude 7.5 Papua New Guinea earthquakes. The AIC test is shown to be able to accurately select the most appropriate model and the selected W-phase inversion is shown to yield reliable solutions that match previously published analyses of the same events.

  6. Double point source W-phase inversion: Real-time implementation and automated model selection

    NASA Astrophysics Data System (ADS)

    Nealy, Jennifer L.; Hayes, Gavin P.

    2015-12-01

    Rapid and accurate characterization of an earthquake source is an extremely important and ever evolving field of research. Within this field, source inversion of the W-phase has recently been shown to be an effective technique, which can be efficiently implemented in real-time. An extension to the W-phase source inversion is presented in which two point sources are derived to better characterize complex earthquakes. A single source inversion followed by a double point source inversion with centroid locations fixed at the single source solution location can be efficiently run as part of earthquake monitoring network operational procedures. In order to determine the most appropriate solution, i.e., whether an earthquake is most appropriately described by a single source or a double source, an Akaike information criterion (AIC) test is performed. Analyses of all earthquakes of magnitude 7.5 and greater occurring since January 2000 were performed with extended analyses of the September 29, 2009 magnitude 8.1 Samoa earthquake and the April 19, 2014 magnitude 7.5 Papua New Guinea earthquake. The AIC test is shown to be able to accurately select the most appropriate model and the selected W-phase inversion is shown to yield reliable solutions that match published analyses of the same events.

  7. Modeling solvation effects in real-space and real-time within density functional approaches

    SciTech Connect

    Delgado, Alain; Corni, Stefano; Pittalis, Stefano; Rozzi, Carlo Andrea

    2015-10-14

    The Polarizable Continuum Model (PCM) can be used in conjunction with Density Functional Theory (DFT) and its time-dependent extension (TDDFT) to simulate the electronic and optical properties of molecules and nanoparticles immersed in a dielectric environment, typically liquid solvents. In this contribution, we develop a methodology to account for solvation effects in real-space (and real-time) (TD)DFT calculations. The boundary elements method is used to calculate the solvent reaction potential in terms of the apparent charges that spread over the van der Waals solute surface. In a real-space representation, this potential may exhibit a Coulomb singularity at grid points that are close to the cavity surface. We propose a simple approach to regularize such singularity by using a set of spherical Gaussian functions to distribute the apparent charges. We have implemented the proposed method in the OCTOPUS code and present results for the solvation free energies and solvatochromic shifts for a representative set of organic molecules in water.

  8. Modeling solvation effects in real-space and real-time within density functional approaches

    NASA Astrophysics Data System (ADS)

    Delgado, Alain; Corni, Stefano; Pittalis, Stefano; Rozzi, Carlo Andrea

    2015-10-01

    The Polarizable Continuum Model (PCM) can be used in conjunction with Density Functional Theory (DFT) and its time-dependent extension (TDDFT) to simulate the electronic and optical properties of molecules and nanoparticles immersed in a dielectric environment, typically liquid solvents. In this contribution, we develop a methodology to account for solvation effects in real-space (and real-time) (TD)DFT calculations. The boundary elements method is used to calculate the solvent reaction potential in terms of the apparent charges that spread over the van der Waals solute surface. In a real-space representation, this potential may exhibit a Coulomb singularity at grid points that are close to the cavity surface. We propose a simple approach to regularize such singularity by using a set of spherical Gaussian functions to distribute the apparent charges. We have implemented the proposed method in the Octopus code and present results for the solvation free energies and solvatochromic shifts for a representative set of organic molecules in water.

  9. Real-time three dimensional echo-guided closure of atrial septal defect: an experimental model.

    PubMed

    Orihashi, Kazumasa; Sueda, Taijiro; Okada, Kenji; Imai, Katsuhiko; Ban, Koji; Hamamoto, Masaki

    2005-10-01

    Real-time 3D echo may open the way to off-pump closure of an atrial septal defect with a robotic surgery technique without remnant of closure device. We report the preliminary results of 3D echo-guided closure of defect in an experimental model. A sheet with an oval defect immersed in water was visualized with 3D echo as well as surgical instruments. The defect was closed under echo guidance. Visualization of objects and instruments, and feasibility and problems of this technique were examined. The defect was visualized like an endoscopic view. Changing the view point without moving the transducer was a unique advantage. Visualization of instruments was acceptable with the lowest gain level. Acoustic shadow was helpful for comprehending the spatial relationship among the objects. Position of needle entry could be confirmed by the movement of the sheet. As the defect was sutured, fold convergence appeared on the sheet. Difficulties were encountered in passing the needle between instruments because of echo dropout. The string was poorly visualized. 3D echo-guided suturing was feasible with adequate image quality. However, an improvement of the surface of instruments and a wider scanning area is necessary for achieving surgical procedures with more safety and reliability.

  10. Evaluation of Lung Metastasis in Mouse Mammary Tumor Models by Quantitative Real-time PCR

    PubMed Central

    Abt, Melissa A.; Grek, Christina L.; Ghatnekar, Gautam S.; Yeh, Elizabeth S.

    2016-01-01

    Metastatic disease is the spread of malignant tumor cells from the primary cancer site to a distant organ and is the primary cause of cancer associated death 1. Common sites of metastatic spread include lung, lymph node, brain, and bone 2. Mechanisms that drive metastasis are intense areas of cancer research. Consequently, effective assays to measure metastatic burden in distant sites of metastasis are instrumental for cancer research. Evaluation of lung metastases in mammary tumor models is generally performed by gross qualitative observation of lung tissue following dissection. Quantitative methods of evaluating metastasis are currently limited to ex vivo and in vivo imaging based techniques that require user defined parameters. Many of these techniques are at the whole organism level rather than the cellular level 3–6. Although newer imaging methods utilizing multi-photon microscopy are able to evaluate metastasis at the cellular level 7, these highly elegant procedures are more suited to evaluating mechanisms of dissemination rather than quantitative assessment of metastatic burden. Here, a simple in vitro method to quantitatively assess metastasis is presented. Using quantitative Real-time PCR (QRT-PCR), tumor cell specific mRNA can be detected within the mouse lung tissue. PMID:26862835

  11. Evaluation of Lung Metastasis in Mouse Mammary Tumor Models by Quantitative Real-time PCR.

    PubMed

    Abt, Melissa A; Grek, Christina L; Ghatnekar, Gautam S; Yeh, Elizabeth S

    2016-01-29

    Metastatic disease is the spread of malignant tumor cells from the primary cancer site to a distant organ and is the primary cause of cancer associated death. Common sites of metastatic spread include lung, lymph node, brain, and bone. Mechanisms that drive metastasis are intense areas of cancer research. Consequently, effective assays to measure metastatic burden in distant sites of metastasis are instrumental for cancer research. Evaluation of lung metastases in mammary tumor models is generally performed by gross qualitative observation of lung tissue following dissection. Quantitative methods of evaluating metastasis are currently limited to ex vivo and in vivo imaging based techniques that require user defined parameters. Many of these techniques are at the whole organism level rather than the cellular level. Although newer imaging methods utilizing multi-photon microscopy are able to evaluate metastasis at the cellular level, these highly elegant procedures are more suited to evaluating mechanisms of dissemination rather than quantitative assessment of metastatic burden. Here, a simple in vitro method to quantitatively assess metastasis is presented. Using quantitative Real-time PCR (QRT-PCR), tumor cell specific mRNA can be detected within the mouse lung tissue.

  12. LANL* V1.0: a radiation belt drift shell model suitable for real-time and reanalysis applications

    SciTech Connect

    Koller, Josep; Reeves, Geoffrey D; Friedel, Reiner H W

    2008-01-01

    Space weather modeling, forecasts, and predictions, especially for the radiation belts in the inner magnetosphere, require detailed information about the Earth's magnetic field. Results depend on the magnetic field model and the L* (pron. L-star) values which are used to describe particle drift shells. Space wather models require integrating particle motions along trajectories that encircle the Earth. Numerical integration typically takes on the order of 10{sup 5} calls to a magnetic field model which makes the L* calculations very slow, in particular when using a dynamic and more accurate magnetic field model. Researchers currently tend to pick simplistic models over more accurate ones but also risking large inaccuracies and even wrong conclusions. For example, magnetic field models affect the calculation of electron phase space density by applying adiabatic invariants including the drift shell value L*. We present here a new method using a surrogate model based on a neural network technique to replace the time consuming L* calculations made with modern magnetic field models. The advantage of surrogate models (or meta-models) is that they can compute the same output in a fraction of the time while adding only a marginal error. Our drift shell model LANL* (Los Alamos National Lab L-star) is based on L* calculation using the TSK03 model. The surrogate model has currently been tested and validated only for geosynchronous regions but the method is generally applicable to any satellite orbit. Computations with the new model are several million times faster compared to the standard integration method while adding less than 1% error. Currently, real-time applications for forecasting and even nowcasting inner magnetospheric space weather is limited partly due to the long computing time of accurate L* values. Without them, real-time applications are limited in accuracy. Reanalysis application of past conditions in the inner magnetosphere are used to understand physical

  13. Insights into explosion dynamics at Stromboli in 2009 from ash samples collected in real-time

    NASA Astrophysics Data System (ADS)

    Taddeucci, J.; Lautze, N.; Andronico, D.; D'Auria, L.; Niemeijer, A.; Houghton, B.; Scarlato, P.

    2012-04-01

    Rapid characterization of tephra during explosive eruptions can provide valuable insights into eruptive mechanisms, also integrating other monitoring systems. Here we reveal a perspective on Stromboli's conduit processes by linking ash textures to geophysical estimates of eruption parameters of observed explosions. A three day campaign at Stromboli was undertaken by Italy's Istituto Nazionale di Geofisica e Vulcanologia (INGV) in October 2009. At this time activity was moderately intense, with an average 4 to 5, both ash-rich and ash-poor, explosions per hour at each the SW and NE vents. A total of fifteen ash samples were collected in real time. We used binocular and scanning electron microscopes to analyze the components, grain size and morphology distributions, and surface chemistry of ash particles within eight selected samples. In addition, the INGV monitoring network provided visual, thermal, and seismic information on the explosions that generated the sampled ash. In each sample, the proportion of fluidal, glassy sideromelane (as opposed to blocky, microcrystalline tachylite plus lithics), the degree of "chemical freshness" (as opposed to chemical alteration), and the average size of particles appear to correlate directly with the maximum height and the seismic amplitude of the corresponding explosion, and inversely correlate with the amount of ash erupted, as estimated by monitoring videos. These observations suggest that more violent explosions (i.e., those driven by the release of larger and more pressurized gas volumes) produce ash via the fragmentation of hotter, more fluid magma, while weaker ones mostly erupt ash-sized particles derived by the fragmentation of colder magma and incorporation of conduit wall debris. The formation of fluidal ash particles (up to Pele's hairs) requires aerodynamic deformation of a relatively low-viscosity magma, in agreement with the strong acceleration imposed upon fragmented magma clots by the rapid expansion of

  14. Diffusion Modelling as a Useful Petrological Tool for Near-Real-Time Volcanic Eruption Monitoring

    NASA Astrophysics Data System (ADS)

    Couperthwaite, F.; Morgan, D. J.; Thordarson, T.; Shea, T.; Harvey, J.; Trusdell, F.; Pankhurst, M. J.

    2015-12-01

    Diffusion modelling is a well-established petrological technique for investigating the timescales of sub-surface processes occurring within magma storage bodies and transport systems prior to eruption. The technique typically produces - at best - results some weeks after a volcanic eruption has commenced. This contribution describes progress made on a user-friendly, easy-to-use petrological 'tool' that can be deployed in near-real time at the onset of and during an eruption. This is important for fast timescale retrieval (within days rather than weeks) without compromising the reliability of the timescale retrieved. This has implications for eruption monitoring and hazard mitigation, providing a petrological time-series complementing existing geophysical monitoring techniques. Current methods are constrained by data processing rates and the geometrical corrections required to control for random sectioning, crystal shape uncertainties and mineral anisotropy. Using a set of Piton de la Fournaise (Réunion Island) lava flow samples and a suite of Mauna Loa (HI, US) air fall and lava flow samples, magmatic timescales for Mg-Fe diffusion in olivine have been retrieved. Piton has a monodisperse crystal population, making a near-perfect baseline from which to pick apart the current diffusion modelling method. In so doing, a greater understanding of the sources of scatter and uncertainty in the process of timescale retrieval was obtained. The variety of potential sectioning orientations and their interaction with diffusion processes led to the proposal by Shea et al, 2015, in press, of selection rules to select boundaries, based on numerical models. Combined with evaluations of crystal shape, crystal axial ratios, interfacial angles, U-stage measurements and a statistical approach, such selection rules should allow the orientation of the grain within a sample to be inferred, negating the need for independent EBSD measurements and enabling a faster processing technique.

  15. Electron dynamics in complex environments with real-time time dependent density functional theory in a QM-MM framework

    SciTech Connect

    Morzan, Uriel N.; Ramírez, Francisco F.; Scherlis, Damián A. E-mail: mcgl@qb.ffyb.uba.ar; Lebrero, Mariano C. González E-mail: mcgl@qb.ffyb.uba.ar

    2014-04-28

    This article presents a time dependent density functional theory (TDDFT) implementation to propagate the Kohn-Sham equations in real time, including the effects of a molecular environment through a Quantum-Mechanics Molecular-Mechanics (QM-MM) hamiltonian. The code delivers an all-electron description employing Gaussian basis functions, and incorporates the Amber force-field in the QM-MM treatment. The most expensive parts of the computation, comprising the commutators between the hamiltonian and the density matrix—required to propagate the electron dynamics—, and the evaluation of the exchange-correlation energy, were migrated to the CUDA platform to run on graphics processing units, which remarkably accelerates the performance of the code. The method was validated by reproducing linear-response TDDFT results for the absorption spectra of several molecular species. Two different schemes were tested to propagate the quantum dynamics: (i) a leap-frog Verlet algorithm, and (ii) the Magnus expansion to first-order. These two approaches were confronted, to find that the Magnus scheme is more efficient by a factor of six in small molecules. Interestingly, the presence of iron was found to seriously limitate the length of the integration time step, due to the high frequencies associated with the core-electrons. This highlights the importance of pseudopotentials to alleviate the cost of the propagation of the inner states when heavy nuclei are present. Finally, the methodology was applied to investigate the shifts induced by the chemical environment on the most intense UV absorption bands of two model systems of general relevance: the formamide molecule in water solution, and the carboxy-heme group in Flavohemoglobin. In both cases, shifts of several nanometers are observed, consistently with the available experimental data.

  16. Electron dynamics in complex environments with real-time time dependent density functional theory in a QM-MM framework

    NASA Astrophysics Data System (ADS)

    Morzan, Uriel N.; Ramírez, Francisco F.; Oviedo, M. Belén; Sánchez, Cristián G.; Scherlis, Damián A.; Lebrero, Mariano C. González

    2014-04-01

    This article presents a time dependent density functional theory (TDDFT) implementation to propagate the Kohn-Sham equations in real time, including the effects of a molecular environment through a Quantum-Mechanics Molecular-Mechanics (QM-MM) hamiltonian. The code delivers an all-electron description employing Gaussian basis functions, and incorporates the Amber force-field in the QM-MM treatment. The most expensive parts of the computation, comprising the commutators between the hamiltonian and the density matrix—required to propagate the electron dynamics—, and the evaluation of the exchange-correlation energy, were migrated to the CUDA platform to run on graphics processing units, which remarkably accelerates the performance of the code. The method was validated by reproducing linear-response TDDFT results for the absorption spectra of several molecular species. Two different schemes were tested to propagate the quantum dynamics: (i) a leap-frog Verlet algorithm, and (ii) the Magnus expansion to first-order. These two approaches were confronted, to find that the Magnus scheme is more efficient by a factor of six in small molecules. Interestingly, the presence of iron was found to seriously limitate the length of the integration time step, due to the high frequencies associated with the core-electrons. This highlights the importance of pseudopotentials to alleviate the cost of the propagation of the inner states when heavy nuclei are present. Finally, the methodology was applied to investigate the shifts induced by the chemical environment on the most intense UV absorption bands of two model systems of general relevance: the formamide molecule in water solution, and the carboxy-heme group in Flavohemoglobin. In both cases, shifts of several nanometers are observed, consistently with the available experimental data.

  17. Adaptive Optics Correction in Real-Time for Dynamic Wavefront Errors

    DTIC Science & Technology

    1990-03-15

    This paper reports on the principles for the use of, and the experimental results obtained from, an adaptive optics system for correcting dynamic...control system. Keywords: Adaptive optics ; Wavefront sensing; Deformable mirror; Chinese translations.

  18. Real-Time Target Position Estimation Using Stereoscopic Kilovoltage/Megavoltage Imaging and External Respiratory Monitoring for Dynamic Multileaf Collimator Tracking

    SciTech Connect

    Cho, Byungchul; Poulsen, Per Rugaard; Sawant, Amit; Ruan, Dan; Keall, Paul J.

    2011-01-01

    Purpose: To develop a real-time target position estimation method using stereoscopic kilovoltage (kV)/megavoltage (MV) imaging and external respiratory monitoring, and to investigate the performance of a dynamic multileaf collimator tracking system using this method. Methods and Materials: The real-time three-dimensional internal target position estimation was established by creating a time-varying correlation model that connected the external respiratory signals with the internal target motion measured intermittently using kV/MV imaging. The method was integrated into a dynamic multileaf collimator tracking system. Tracking experiments were performed for 10 thoracic/abdominal traces. A three-dimensional motion platform carrying a gold marker and a separate one-dimensional motion platform were used to reproduce the target and external respiratory motion, respectively. The target positions were detected by kV (1 Hz) and MV (5.2 Hz) imaging, and external respiratory motion was captured by an optical system (30 Hz). The beam-target alignment error was quantified as the positional difference between the target and circular beam center on the MV images acquired during tracking. The correlation model error was quantified by comparing a model estimate and measured target positions. Results: The root-mean-square errors in the beam-target alignment that had ranged from 3.1 to 7.6 mm without tracking were reduced to <1.5 mm with tracking, except during the model building period (6 s). The root-mean-square error in the correlation model was submillimeters in all directions. Conclusion: A novel real-time target position estimation method was developed and integrated into a dynamic multileaf collimator tracking system and demonstrated an average submillimeter geometric accuracy after initializing the internal/external correlation model. The method used hardware tools available on linear accelerators and therefore shows promise for clinical implementation.

  19. Real-Time Monitoring of Non-linear Suicidal Dynamics: Methodology and a Demonstrative Case Report

    PubMed Central

    Fartacek, Clemens; Schiepek, Günter; Kunrath, Sabine; Fartacek, Reinhold; Plöderl, Martin

    2016-01-01

    In recent years, a number of different authors have stressed the usefulness of non-linear dynamic systems approach in suicide research and suicide prevention. This approach applies specific methods of time series analysis and, consequently, it requires a continuous and fine-meshed assessment of the processes under consideration. The technical means for this kind of process assessment and process analysis are now available. This paper outlines how suicidal dynamics can be monitored in high-risk patients by an Internet-based application for continuous self-assessment with integrated tools of non-linear time series analysis: the Synergetic Navigation System. This procedure is illustrated by data from a patient who attempted suicide at the end of a 90-day monitoring period. Additionally, future research topics and clinical applications of a non-linear dynamic systems approach in suicidology are discussed. PMID:26913016

  20. Real-time monitoring of metabolic function in liver-on-chip microdevices tracks the dynamics of mitochondrial dysfunction

    PubMed Central

    Bavli, Danny; Prill, Sebastian; Ezra, Elishai; Levy, Gahl; Cohen, Merav; Vinken, Mathieu; Vanfleteren, Jan; Jaeger, Magnus; Nahmias, Yaakov

    2016-01-01

    Microfluidic organ-on-a-chip technology aims to replace animal toxicity testing, but thus far has demonstrated few advantages over traditional methods. Mitochondrial dysfunction plays a critical role in the development of chemical and pharmaceutical toxicity, as well as pluripotency and disease processes. However, current methods to evaluate mitochondrial activity still rely on end-point assays, resulting in limited kinetic and prognostic information. Here, we present a liver-on-chip device capable of maintaining human tissue for over a month in vitro under physiological conditions. Mitochondrial respiration was monitored in real time using two-frequency phase modulation of tissue-embedded phosphorescent microprobes. A computer-controlled microfluidic switchboard allowed contiguous electrochemical measurements of glucose and lactate, providing real-time analysis of minute shifts from oxidative phosphorylation to anaerobic glycolysis, an early indication of mitochondrial stress. We quantify the dynamics of cellular adaptation to mitochondrial damage and the resulting redistribution of ATP production during rotenone-induced mitochondrial dysfunction and troglitazone (Rezulin)-induced mitochondrial stress. We show troglitazone shifts metabolic fluxes at concentrations previously regarded as safe, suggesting a mechanism for its observed idiosyncratic effect. Our microfluidic platform reveals the dynamics and strategies of cellular adaptation to mitochondrial damage, a unique advantage of organ-on-chip technology. PMID:27044092

  1. Real Time Dynamics of Laser Activated Interface Processes at the Molecular Scale

    SciTech Connect

    Eric Borguet

    2007-12-30

    Nanotechnology is one of the most interesting and challenging frontiers of science and technology. We are motivated by the belief that progress will come from improved understanding and control of structure, dynamics and reactivity at interfaces. First, we provide a summary of our projects and key findings. The following pages provide a more detailed account.

  2. Decision Consequence Model (DCM): Integrating environmental data and analysis into real time decision making

    SciTech Connect

    Cimorelli, A.J.; Stahl, C.H.; Chow, A.H.; Fernandez, C.

    1999-07-01

    A critical evaluation of the many environmental issues facing EPA Region 3 has established five major priorities: (1) ozone pollution (and its precursors); (2) impacts of acidification (acid deposition and acid mine drainage); (3) eutrophication of the Chesapeake Bay from atmospheric nitrogen deposition; (4) Cities/Urban Environment (ozone, particulate matter (PM), air toxics are some of the air components); and (5) Climate Change. Recognizing the complex nature of the systems controlling these issues, Region III's Air Protection Division (APD) is developing a decision support tool, i.e., the Decision Consequence Model (DCM), that will integrate and automate the analysis of environmental impacts in a manner that allows them to holistically address these regional priorities. Using this tool the authors intend to consider the interdependency of pollutants and their environmental impacts in order to support real-time decision making. The purpose of this paper is to outline the basic concept of the DCM and to present an example set of environmental indicators to illustrate how the DCM will be used to evaluate environmental impacts. The authors will discuss their process of indicator development, and present an example suite of indicators to provide a concrete example of the concepts presented above and, to illustrate the utility of the DCM to simultaneously evaluate multiple effects of a single pollutant. They will discuss the type of indicators chosen for this example as well as the general criteria the DCM indicators must satisfy. The framework that was developed to construct the indicators is discussed and used to calculate the example indicators. The yearly magnitudes of these example indicators are calculated for various multi-year periods to show their behavior over time.

  3. Aircraft Conflict Analysis and Real-Time Conflict Probing Using Probabilistic Trajectory Modeling

    NASA Technical Reports Server (NTRS)

    Yang, Lee C.; Kuchar, James K.

    2000-01-01

    Methods for maintaining separation between aircraft in the current airspace system have been built from a foundation of structured routes and evolved procedures. However, as the airspace becomes more congested and the chance of failures or operational error become more problematic, automated conflict alerting systems have been proposed to help provide decision support and to serve as traffic monitoring aids. The problem of conflict detection and resolution has been tackled from a number of different ways, but in this thesis, it is recast as a problem of prediction in the presence of uncertainties. Much of the focus is concentrated on the errors and uncertainties from the working trajectory model used to estimate future aircraft positions. The more accurate the prediction, the more likely an ideal (no false alarms, no missed detections) alerting system can be designed. Additional insights into the problem were brought forth by a review of current operational and developmental approaches found in the literature. An iterative, trial and error approach to threshold design was identified. When examined from a probabilistic perspective, the threshold parameters were found to be a surrogate to probabilistic performance measures. To overcome the limitations in the current iterative design method, a new direct approach is presented where the performance measures are directly computed and used to perform the alerting decisions. The methodology is shown to handle complex encounter situations (3-D, multi-aircraft, multi-intent, with uncertainties) with relative ease. Utilizing a Monte Carlo approach, a method was devised to perform the probabilistic computations in near realtime. Not only does this greatly increase the method's potential as an analytical tool, but it also opens up the possibility for use as a real-time conflict alerting probe. A prototype alerting logic was developed and has been utilized in several NASA Ames Research Center experimental studies.

  4. Real-time passive tracking for multi-touch medical modeling and simulation.

    PubMed

    Guerra, Christopher J; Hackett, Matthew; Carrola, John T; Couvillion, Warren C; Chambers, David R; Desai, Sapna A

    2014-01-01

    The military medical community expects to minimize use of live tissue and cadavers for training purposes. This research demonstrates an innovative use of synthetic tissue and passive tracking computer vision to create a real-time, interactive environment for training medical staff.

  5. Inverse modelling for real-time estimation of radiological consequences in the early stage of an accidental radioactivity release.

    PubMed

    Pecha, Petr; Šmídl, Václav

    2016-11-01

    A stepwise sequential assimilation algorithm is proposed based on an optimisation approach for recursive parameter estimation and tracking of radioactive plume propagation in the early stage of a radiation accident. Predictions of the radiological situation in each time step of the plume propagation are driven by an existing short-term meteorological forecast and the assimilation procedure manipulates the model parameters to match the observations incoming concurrently from the terrain. Mathematically, the task is a typical ill-posed inverse problem of estimating the parameters of the release. The proposed method is designated as a stepwise re-estimation of the source term release dynamics and an improvement of several input model parameters. It results in a more precise determination of the adversely affected areas in the terrain. The nonlinear least-squares regression methodology is applied for estimation of the unknowns. The fast and adequately accurate segmented Gaussian plume model (SGPM) is used in the first stage of direct (forward) modelling. The subsequent inverse procedure infers (re-estimates) the values of important model parameters from the actual observations. Accuracy and sensitivity of the proposed method for real-time forecasting of the accident propagation is studied. First, a twin experiment generating noiseless simulated "artificial" observations is studied to verify the minimisation algorithm. Second, the impact of the measurement noise on the re-estimated source release rate is examined. In addition, the presented method can be used as a proposal for more advanced statistical techniques using, e.g., importance sampling.

  6. Breaking Computational Barriers: Real-time Analysis and Optimization with Large-scale Nonlinear Models via Model Reduction

    SciTech Connect

    Carlberg, Kevin Thomas; Drohmann, Martin; Tuminaro, Raymond S.; Boggs, Paul T.; Ray, Jaideep; van Bloemen Waanders, Bart Gustaaf

    2014-10-01

    Model reduction for dynamical systems is a promising approach for reducing the computational cost of large-scale physics-based simulations to enable high-fidelity models to be used in many- query (e.g., Bayesian inference) and near-real-time (e.g., fast-turnaround simulation) contexts. While model reduction works well for specialized problems such as linear time-invariant systems, it is much more difficult to obtain accurate, stable, and efficient reduced-order models (ROMs) for systems with general nonlinearities. This report describes several advances that enable nonlinear reduced-order models (ROMs) to be deployed in a variety of time-critical settings. First, we present an error bound for the Gauss-Newton with Approximated Tensors (GNAT) nonlinear model reduction technique. This bound allows the state-space error for the GNAT method to be quantified when applied with the backward Euler time-integration scheme. Second, we present a methodology for preserving classical Lagrangian structure in nonlinear model reduction. This technique guarantees that important properties--such as energy conservation and symplectic time-evolution maps--are preserved when performing model reduction for models described by a Lagrangian formalism (e.g., molecular dynamics, structural dynamics). Third, we present a novel technique for decreasing the temporal complexity --defined as the number of Newton-like iterations performed over the course of the simulation--by exploiting time-domain data. Fourth, we describe a novel method for refining projection-based reduced-order models a posteriori using a goal-oriented framework similar to mesh-adaptive h -refinement in finite elements. The technique allows the ROM to generate arbitrarily accurate solutions, thereby providing the ROM with a 'failsafe' mechanism in the event of insufficient training data. Finally, we present the reduced-order model error surrogate (ROMES) method for statistically quantifying reduced- order-model errors. This

  7. Time-resolved x-ray photoelectron spectroscopy techniques for real-time studies of interfacial charge transfer dynamics

    NASA Astrophysics Data System (ADS)

    Shavorskiy, Andrey; Cordones, Amy; Vura-Weis, Josh; Siefermann, Katrin; Slaughter, Daniel; Sturm, Felix; Weise, Fabian; Bluhm, Hendrik; Strader, Matthew; Cho, Hana; Lin, Ming-Fu; Bacellar, Camila; Khurmi, Champak; Hertlein, Marcus; Guo, Jinghua; Tyliszczak, Tolek; Prendergast, David; Coslovich, Giacomo; Robinson, Joseph; Kaindl, Robert A.; Schoenlein, Robert W.; Belkacem, Ali; Weber, Thorsten; Neumark, Daniel M.; Leone, Stephen R.; Nordlund, Dennis; Ogasawara, Hirohito; Nilsson, Anders R.; Krupin, Oleg; Turner, Joshua J.; Schlotter, William F.; Holmes, Michael R.; Heimann, Philip A.; Messerschmidt, Marc; Minitti, Michael P.; Beye, Martin; Gul, Sheraz; Zhang, Jin Z.; Huse, Nils; Gessner, Oliver

    2013-04-01

    X-ray based spectroscopy techniques are particularly well suited to gain access to local oxidation states and electronic dynamics in complex systems with atomic pinpoint accuracy. Traditionally, these techniques are applied in a quasi-static fashion that usually highlights the steady-state properties of a system rather than the fast dynamics that often define the system function on a molecular level. Novel x-ray spectroscopy techniques enabled by free electron lasers (FELs) and synchrotron based pump-probe schemes provide the opportunity to monitor intramolecular and interfacial charge transfer processes in real-time and with element and chemical specificity. Two complementary time-domain xray photoelectron spectroscopy techniques are presented that are applied at the Linac Coherent Light Source (LCLS) and the Advanced Light Source (ALS) to study charge transfer processes in N3 dye-sensitized ZnO semiconductor nanocrystals, which are at the heart of emerging light-harvesting technologies.

  8. Time-resolved x-ray photoelectron spectroscopy techniques for real-time studies of interfacial charge transfer dynamics

    SciTech Connect

    Shavorskiy, Andrey; Hertlein, Marcus; Guo Jinghua; Tyliszczak, Tolek; Cordones, Amy; Vura-Weis, Josh; Siefermann, Katrin; Slaughter, Daniel; Sturm, Felix; Weise, Fabian; Khurmi, Champak; Belkacem, Ali; Weber, Thorsten; Gessner, Oliver; Bluhm, Hendrik; Strader, Matthew; Cho, Hana; Coslovich, Giacomo; Kaindl, Robert A.; Lin, Ming-Fu; and others

    2013-04-19

    X-ray based spectroscopy techniques are particularly well suited to gain access to local oxidation states and electronic dynamics in complex systems with atomic pinpoint accuracy. Traditionally, these techniques are applied in a quasi-static fashion that usually highlights the steady-state properties of a system rather than the fast dynamics that often define the system function on a molecular level. Novel x-ray spectroscopy techniques enabled by free electron lasers (FELs) and synchrotron based pump-probe schemes provide the opportunity to monitor intramolecular and interfacial charge transfer processes in real-time and with element and chemical specificity. Two complementary time-domain xray photoelectron spectroscopy techniques are presented that are applied at the Linac Coherent Light Source (LCLS) and the Advanced Light Source (ALS) to study charge transfer processes in N3 dye-sensitized ZnO semiconductor nanocrystals, which are at the heart of emerging light-harvesting technologies.

  9. Real-Time and High-Fidelity Simulation Environment for Autonomous Ground Vehicle Dynamics

    NASA Technical Reports Server (NTRS)

    Cameron, Jonathan; Myint, Steven; Kuo, Calvin; Jain, Abhi; Grip, Havard; Jayakumar, Paramsothy; Overholt, Jim

    2013-01-01

    This paper reports on a collaborative project between U.S. Army TARDEC and Jet Propulsion Laboratory (JPL) to develop a unmanned ground vehicle (UGV) simulation model using the ROAMS vehicle modeling framework. Besides modeling the physical suspension of the vehicle, the sensing and navigation of the HMMWV vehicle are simulated. Using models of urban and off-road environments, the HMMWV simulation was tested in several ways, including navigation in an urban environment with obstacle avoidance and the performance of a lane change maneuver.

  10. Real-time dose computation: GPU-accelerated source modeling and superposition/convolution

    SciTech Connect

    Jacques, Robert; Wong, John; Taylor, Russell; McNutt, Todd

    2011-01-15

    } times were 8.3 and 94 s, respectively, on an AMD (Sunnyvale, CA) Opteron 254 (two cores, 2.8 GHz). Conclusions: The authors have completed a comprehensive, GPU-accelerated dose engine in order to provide a substantial performance gain over CPU based implementations. Real-time dose computation is feasible with the accuracy levels of the superposition/convolution algorithm.

  11. Real-time imaging of hydrogen peroxide dynamics in vegetative and pathogenic hyphae of Fusarium graminearum

    PubMed Central

    Mentges, Michael; Bormann, Jörg

    2015-01-01

    Balanced dynamics of reactive oxygen species in the phytopathogenic fungus Fusarium graminearum play key roles for development and infection. To monitor those dynamics, ratiometric analysis using the novel hydrogen peroxide (H2O2) sensitive fluorescent indicator protein HyPer-2 was established for the first time in phytopathogenic fungi. H2O2 changes the excitation spectrum of HyPer-2 with an excitation maximum at 405 nm for the reduced and 488 nm for the oxidized state, facilitating ratiometric readouts with maximum emission at 516 nm. HyPer-2 analyses were performed using a microtiter fluorometer and confocal laser scanning microscopy (CLSM). Addition of external H2O2 to mycelia caused a steep and transient increase in fluorescence excited at 488 nm. This can be reversed by the addition of the reducing agent dithiothreitol. HyPer-2 in F. graminearum is highly sensitive and specific to H2O2 even in tiny amounts. Hyperosmotic treatment elicited a transient internal H2O2 burst. Hence, HyPer-2 is suitable to monitor the intracellular redox balance. Using CLSM, developmental processes like nuclear division, tip growth, septation, and infection structure development were analyzed. The latter two processes imply marked accumulations of intracellular H2O2. Taken together, HyPer-2 is a valuable and reliable tool for the analysis of environmental conditions, cellular development, and pathogenicity. PMID:26446493

  12. Highly Dynamic and Adaptive Traffic Congestion Avoidance in Real-Time Inspired by Honey Bee Behavior

    NASA Astrophysics Data System (ADS)

    Wedde, Horst F.; Lehnhoff, Sebastian; van Bonn, Bernhard; Bay, Z.; Becker, S.; Böttcher, S.; Brunner, C.; Büscher, A.; Fürst, T.; Lazarescu, A. M.; Rotaru, E.; Senge, S.; Steinbach, B.; Yilmaz, F.; Zimmermann, T.

    Traffic congestions have become a major problem in metropolitan areas world-wide, within and between cities, to an extent where they make driving and transportation times largely unpredictable. Due to the highly dynamic character of congestion building and dissolving this phenomenon appears even to resist a formal treatment. Static approaches, and even more their global management, have proven counterproductive in practice. Given the latest progress in VANET technology and the remarkable commercially driven efforts like in the European C2C consortium, or the VSC Project in the US, allow meanwhile to tackle various aspects of traffic regulation through VANET communication. In this paper we introduce a novel, completely decentralized multi-agent routing algorithm (termed BeeJamA) which we have derived from the foraging behavior of honey bees. It is highly dynamic, adaptive, robust, and scalable, and it allows for both avoiding congestions, and minimizing traveling times to individual destinations. Vehicle guidance is provided well ahead of every intersection, depending on the individual speeds. Thus strict deadlines are imposed on, and respected by, the BeeJamA algorithm. We report on extensive simulation experiments which show the superior performance of BeeJamA over conventional approaches.

  13. Advanced fluorescence microscopy methods for the real-time study of transcription and chromatin dynamics

    PubMed Central

    Annibale, Paolo; Gratton, Enrico

    2014-01-01

    In this contribution we provide an overview of the recent advances allowed by the use of fluorescence microscopy methods in the study of transcriptional processes and their interplay with the chromatin architecture in living cells. Although the use of fluorophores to label nucleic acids dates back at least to about half a century ago,1 two recent breakthroughs have effectively opened the way to use fluorescence routinely for specific and quantitative probing of chromatin organization and transcriptional activity in living cells: namely, the possibility of labeling first the chromatin loci and then the mRNA synthesized from a gene using fluorescent proteins. In this contribution we focus on methods that can probe rapid dynamic processes by analyzing fast fluorescence fluctuations. PMID:25764219

  14. Real-time investigation of dynamic protein crystallization in living cellsa)

    PubMed Central

    Schönherr, R.; Klinge, M.; Rudolph, J. M.; Fita, K.; Rehders, D.; Lübber, F.; Schneegans, S.; Majoul, I. V.; Duszenko, M.; Betzel, C.; Brandariz-Nuñez, A.; Martinez-Costas, J.; Duden, R.; Redecke, L.

    2015-01-01

    X-ray crystallography requires sufficiently large crystals to obtain structural insights at atomic resolution, routinely obtained in vitro by time-consuming screening. Recently, successful data collection was reported from protein microcrystals grown within living cells using highly brilliant free-electron laser and third-generation synchrotron radiation. Here, we analyzed in vivo crystal growth of firefly luciferase and Green Fluorescent Protein-tagged reovirus μNS by live-cell imaging, showing that dimensions of living cells did not limit crystal size. The crystallization process is highly dynamic and occurs in different cellular compartments. In vivo protein crystallization offers exciting new possibilities for proteins that do not form crystals in vitro. PMID:26798811

  15. Monitoring of Dynamic Microbiological Processes Using Real-Time Flow Cytometry

    PubMed Central

    Arnoldini, Markus; Heck, Tobias; Blanco-Fernández, Alfonso; Hammes, Frederik

    2013-01-01

    We describe a straightforward approach to continuously monitor a variety of highly dynamic microbiological processes in millisecond resolution with flow cytometry, using standard bench-top instrumentation. Four main experimental examples are provided, namely: (1) green fluorescent protein expression by antibiotic-stressed Escherichia coli, (2) fluorescent labeling of heat-induced membrane damage in an autochthonous freshwater bacterial community, (3) the initial growth response of late stationary E. coli cells inoculated into fresh growth media, and (4) oxidative disinfection of a mixed culture of auto-fluorescent microorganisms. These examples demonstrate the broad applicability of the method to diverse biological experiments, showing that it allows the collection of detailed, time-resolved information on complex processes. PMID:24244624

  16. Air Asset to Mission Assignment for Dynamic High-Threat Environments in Real-Time

    DTIC Science & Technology

    2015-03-01

    unlimited 12b. DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) This thesis develops pre- processing algorithms and a mixed integer programming model...the planning timeline and coordination burden by handling the heavy computational aspects of the planning process . It takes as input current aircraft...develops pre- processing algorithms and a mixed integer programming model that solves the route selection and asset-to-mission assignment problem in

  17. Entrainment to a real time fractal visual stimulus modulates fractal gait dynamics.

    PubMed

    Rhea, Christopher K; Kiefer, Adam W; D'Andrea, Susan E; Warren, William H; Aaron, Roy K

    2014-08-01

    Fractal patterns characterize healthy biological systems and are considered to reflect the ability of the system to adapt to varying environmental conditions. Previous research has shown that fractal patterns in gait are altered following natural aging or disease, and this has potential negative consequences for gait adaptability that can lead to increased risk of injury. However, the flexibility of a healthy neurological system to exhibit different fractal patterns in gait has yet to be explored, and this is a necessary step toward understanding human locomotor control. Fifteen participants walked for 15min on a treadmill, either in the absence of a visual stimulus or while they attempted to couple the timing of their gait with a visual metronome that exhibited a persistent fractal pattern (contained long-range correlations) or a random pattern (contained no long-range correlations). The stride-to-stride intervals of the participants were recorded via analog foot pressure switches and submitted to detrended fluctuation analysis (DFA) to determine if the fractal patterns during the visual metronome conditions differed from the baseline (no metronome) condition. DFA α in the baseline condition was 0.77±0.09. The fractal patterns in the stride-to-stride intervals were significantly altered when walking to the fractal metronome (DFA α=0.87±0.06) and to the random metronome (DFA α=0.61±0.10) (both p<.05 when compared to the baseline condition), indicating that a global change in gait dynamics was observed. A variety of strategies were identified at the local level with a cross-correlation analysis, indicating that local behavior did not account for the consistent global changes. Collectively, the results show that a gait dynamics can be shifted in a prescribed manner using a visual stimulus and the shift appears to be a global phenomenon.

  18. Predictive modeling of respiratory tumor motion for real-time prediction of baseline shifts.

    PubMed

    Balasubramanian, A; Shamsuddin, R; Prabhakaran, B; Sawant, A

    2017-03-07

    Baseline shifts in respiratory patterns can result in significant spatiotemporal changes in patient anatomy (compared to that captured during simulation), in turn, causing geometric and dosimetric errors in the administration of thoracic and abdominal radiotherapy. We propose predictive modeling of the tumor motion trajectories for predicting a baseline shift ahead of its occurrence. The key idea is to use the features of the tumor motion trajectory over a 1 min window, and predict the occurrence of a baseline shift in the 5 s that immediately follow (lookahead window). In this study, we explored a preliminary trend-based analysis with multi-class annotations as well as a more focused binary classification analysis. In both analyses, a number of different inter-fraction and intra-fraction training strategies were studied, both offline as well as online, along with data sufficiency and skew compensation for class imbalances. The performance of different training strategies were compared across multiple machine learning classification algorithms, including nearest neighbor, Naïve Bayes, linear discriminant and ensemble Adaboost. The prediction performance is evaluated using metrics such as accuracy, precision, recall and the area under the curve (AUC) for repeater operating characteristics curve. The key results of the trend-based analysis indicate that (i) intra-fraction training strategies achieve highest prediction accuracies (90.5-91.4%); (ii) the predictive modeling yields lowest accuracies (50-60%) when the training data does not include any information from the test patient; (iii) the prediction latencies are as low as a few hundred milliseconds, and thus conducive for real-time prediction. The binary classification performance is promising, indicated by high AUCs (0.96-0.98). It also confirms the utility of prior data from previous patients, and also the necessity of training the classifier on some initial data from the new patient for reasonable

  19. Predictive modeling of respiratory tumor motion for real-time prediction of baseline shifts

    NASA Astrophysics Data System (ADS)

    Balasubramanian, A.; Shamsuddin, R.; Prabhakaran, B.; Sawant, A.

    2017-03-01

    Baseline shifts in respiratory patterns can result in significant spatiotemporal changes in patient anatomy (compared to that captured during simulation), in turn, causing geometric and dosimetric errors in the administration of thoracic and abdominal radiotherapy. We propose predictive modeling of the tumor motion trajectories for predicting a baseline shift ahead of its occurrence. The key idea is to use the features of the tumor motion trajectory over a 1 min window, and predict the occurrence of a baseline shift in the 5 s that immediately follow (lookahead window). In this study, we explored a preliminary trend-based analysis with multi-class annotations as well as a more focused binary classification analysis. In both analyses, a number of different inter-fraction and intra-fraction training strategies were studied, both offline as well as online, along with data sufficiency and skew compensation for class imbalances. The performance of different training strategies were compared across multiple machine learning classification algorithms, including nearest neighbor, Naïve Bayes, linear discriminant and ensemble Adaboost. The prediction performance is evaluated using metrics such as accuracy, precision, recall and the area under the curve (AUC) for repeater operating characteristics curve. The key results of the trend-based analysis indicate that (i) intra-fraction training strategies achieve highest prediction accuracies (90.5–91.4%) (ii) the predictive modeling yields lowest accuracies (50–60%) when the training data does not include any information from the test patient; (iii) the prediction latencies are as low as a few hundred milliseconds, and thus conducive for real-time prediction. The binary classification performance is promising, indicated by high AUCs (0.96–0.98). It also confirms the utility of prior data from previous patients, and also the necessity of training the classifier on some initial data from the new patient for reasonable

  20. Towards a real-time interface between a biomimetic model of sensorimotor cortex and a robotic arm

    PubMed Central

    Dura-Bernal, Salvador; Chadderdon, George L; Neymotin, Samuel A; Francis, Joseph T; Lytton, William W

    2015-01-01

    Brain-machine interfaces can greatly improve the performance of prosthetics. Utilizing biomimetic neuronal modeling in brain machine interfaces (BMI) offers the possibility of providing naturalistic motor-control algorithms for control of a robotic limb. This will allow finer control of a robot, while also giving us new tools to better understand the brain’s use of electrical signals. However, the biomimetic approach presents challenges in integrating technologies across multiple hardware and software platforms, so that the different components can communicate in real-time. We present the first steps in an ongoing effort to integrate a biomimetic spiking neuronal model of motor learning with a robotic arm. The biomimetic model (BMM) was used to drive a simple kinematic two-joint virtual arm in a motor task requiring trial-and-error convergence on a single target. We utilized the output of this model in real time to drive mirroring motion of a Barrett Technology WAM robotic arm through a user datagram protocol (UDP) interface. The robotic arm sent back information on its joint positions, which was then used by a visualization tool on the remote computer to display a realistic 3D virtual model of the moving robotic arm in real time. This work paves the way towards a full closed-loop biomimetic brain-effector system that can be incorporated in a neural decoder for prosthetic control, to be used as a platform for developing biomimetic learning algorithms for controlling real-time devices. PMID:26709323

  1. Real-time automated 3D sensing, detection, and recognition of dynamic biological micro-organic events

    NASA Astrophysics Data System (ADS)

    Javidi, Bahram; Yeom, Seokwon; Moon, Inkyu; Daneshpanah, Mehdi

    2006-05-01

    In this paper, we present an overview of three-dimensional (3D) optical imaging techniques for real-time automated sensing, visualization, and recognition of dynamic biological microorganisms. Real time sensing and 3D reconstruction of the dynamic biological microscopic objects can be performed by single-exposure on-line (SEOL) digital holographic microscopy. A coherent 3D microscope-based interferometer is constructed to record digital holograms of dynamic micro biological events. Complex amplitude 3D images of the biological microorganisms are computationally reconstructed at different depths by digital signal processing. Bayesian segmentation algorithms are applied to identify regions of interest for further processing. A number of pattern recognition approaches are addressed to identify and recognize the microorganisms. One uses 3D morphology of the microorganisms by analyzing 3D geometrical shapes which is composed of magnitude and phase. Segmentation, feature extraction, graph matching, feature selection, and training and decision rules are used to recognize the biological microorganisms. In a different approach, 3D technique is used that are tolerant to the varying shapes of the non-rigid biological microorganisms. After segmentation, a number of sampling patches are arbitrarily extracted from the complex amplitudes of the reconstructed 3D biological microorganism. These patches are processed using a number of cost functions and statistical inference theory for the equality of means and equality of variances between the sampling segments. Also, we discuss the possibility of employing computational integral imaging for 3D sensing, visualization, and recognition of biological microorganisms illuminated under incoherent light. Experimental results with several biological microorganisms are presented to illustrate detection, segmentation, and identification of micro biological events.

  2. Real-time blood circulation and bleeding model for surgical training.

    PubMed

    Boisvert, Jonathan; Poirier, Guillaume; Borgeat, Louis; Godin, Guy

    2013-04-01

    Intraoperative management of bleeding is a critical skill all surgeons must possess. It is, however, very challenging to create a safe and realistic learning environment for its acquisition. In this paper, we propose a simple and efficient approach to integrate blood circulation to computerized surgical simulation systems and allow for real-time processing of punctures, ruptures, and cauterization of blood vessels. Blood pressures and flows are calculated using a system of ordinary differential equations, which can be simulated very efficiently. The equation system itself is constructed using a graph of the vessels' connectivity extracted from magnetic resonance angiograms (MRA) and completed with virtual vessels deduced from the principle of minimum work. Real-time performances of the method are assessed and results are demonstrated on ten patients who underwent a MRA before removal of a brain tumor.

  3. Mathematical models based on transfer functions to estimate tissue temperature during RF cardiac ablation in real time.

    PubMed

    Alba-Martínez, Jose; Trujillo, Macarena; Blasco-Gimenez, Ramon; Berjano, Enrique

    2012-01-01

    Radiofrequency cardiac ablation (RFCA) has been used to treat certain types of cardiac arrhythmias by producing a thermal lesion. Even though a tissue temperature higher than 50ºC is required to destroy the target, thermal mapping is not currently used during RFCA. Our aim was thus to develop mathematical models capable of estimating tissue temperature from tissue characteristics acquired or estimated at the beginning of the procedure (electrical conductivity, thermal conductivity, specific heat and density) and the applied voltage at any time. Biological tissue was considered as a system with an input (applied voltage) and output (tissue temperature), and so the mathematical models were based on transfer functions relating these variables. We used theoretical models based on finite element method to verify the mathematical models. Firstly, we solved finite element models to identify the transfer functions between the temperature at a depth of 4 mm and a constant applied voltage using a 7Fr and 4 mm electrode. The results showed that the relationships can be expressed as first-order transfer functions. Changes in electrical conductivity only affected the static gain of the system, while specific heat variations produced a change in the dynamic system response. In contrast, variations in thermal conductivity modified both the static gain and the dynamic system response. Finally, to assess the performance of the transfer functions obtained, we conducted a new set of computer simulations using a controlled temperature protocol and considering the temperature dependence of the thermal and electrical conductivities, i.e. conditions closer to those found in clinical use. The results showed that the difference between the values estimated from transfer functions and the temperatures obtained from finite element models was less than 4ºC, which suggests that the proposed method could be used to estimate tissue temperature in real time.

  4. Validation of Real-time Modeling of Coronal Mass Ejections Using the WSA-ENLIL+Cone Heliospheric Model

    NASA Astrophysics Data System (ADS)

    Romano, M.; Mays, M. L.; Taktakishvili, A.; MacNeice, P. J.; Zheng, Y.; Pulkkinen, A. A.; Kuznetsova, M. M.; Odstrcil, D.

    2013-12-01

    Modeling coronal mass ejections (CMEs) is of great interest to the space weather research and forecasting communities. We present recent validation work of real-time CME arrival time predictions at different satellites using the WSA-ENLIL+Cone three-dimensional MHD heliospheric model available at the Community Coordinated Modeling Center (CCMC) and performed by the Space Weather Research Center (SWRC). SWRC is an in-house research-based operations team at the CCMC which provides interplanetary space weather forecasting for NASA's robotic missions and performs real-time model validation. The quality of model operation is evaluated by comparing its output to a measurable parameter of interest such as the CME arrival time and geomagnetic storm strength. The Kp index is calculated from the relation given in Newell et al. (2007), using solar wind parameters predicted by the WSA-ENLIL+Cone model at Earth. The CME arrival time error is defined as the difference between the predicted arrival time and the observed in-situ CME shock arrival time at the ACE, STEREO A, or STEREO B spacecraft. This study includes all real-time WSA-ENLIL+Cone model simulations performed between June 2011-2013 (over 400 runs) at the CCMC/SWRC. We report hit, miss, false alarm, and correct rejection statistics for all three spacecraft. For hits we show the average absolute CME arrival time error, and the dependence of this error on CME input parameters such as speed, width, and direction. We also present the predicted geomagnetic storm strength (using the Kp index) error for Earth-directed CMEs.

  5. Forced oscillations dynamic tribometer with real-time insights of lubricated interfaces

    NASA Astrophysics Data System (ADS)

    Yahiaoui, M.; Rigaud, E.; Mazuyer, D.; Cayer-Barrioz, J.

    2017-03-01

    This paper presents an innovative forced oscillations dynamic tribometer, the CHRONOS tribometer, with a lubricated ball-on-flat contact configuration fitted out with an in situ optical visualization system and a triggered high-speed camera. The CHRONOS tribometer generates controlled oscillating kinematics by means of a shaker with a range of strokes from 5 μm to 2.5 mm and an oscillation frequency which can be adjusted from 5 Hz to 250 Hz. Displacement and velocity are measured using a vibrometer. The ball-on-flat mean contact pressure is set between 200 MPa and 600 MPa. During motion, the instantaneous normal and friction forces and the interfacial film thickness distribution (in the nanometer scale) are simultaneously measured. In addition to this instantaneous approach, a more macroscopic approach is developed in terms of moving averages of friction and velocity. Another parameter, the friction-velocity tilt angle, is also introduced. This last parameter may give information on the friction-velocity dependence. Eventually, the experiments performed on the CHRONOS device lead to the representation of synchronized temporal signals of displacement/velocity, friction, and lubricant central film thickness. This superimposition of key parameters reveals time effects introduced by the periodical fluid squeeze and flow in the contact.

  6. Real-time Observation of Vo ordering dynamics in LaCoO3 /STO superlattice

    NASA Astrophysics Data System (ADS)

    Jang, Jae Hyuck; Mishra, Rohan; Kim, Young-Min; He, Qian; Qiao, Liang; Biegalski, Michael D.; Lupini, Andrew R.; Pantelides, Sokrates T.; Pennycook, Stephen J.; Kalinin, Sergei V.; Borisevich, Albina Y.; Oak Ridge National Lab. Collaboration; Vanderbilt University Collaboration; Korea Basic Science Institute Collaboration

    2014-03-01

    Properties of solid oxide fuel cell, catalysts etc. is dependent on the distribution and transport behavior of oxygen ions. In this study, we observe the dynamics of vacancy ordering in LaCoO3/SrTiO3 (LCO/STO) superlattice and LCO films using high angle annular dark field and annular bright field (ABF) STEM. Vo ordering was directly observed by tracking interatomic spacings, withs nucleation, propagation and interaction of different Vo nuclei demonstrated. Moreover, ABF images show that on 1-D (110) vacancy channels form in the depleted layers.In the case for superlattice, very small contribution of vacancy injection was observed. When this approach is applied to 15 u.c. LCO film, however, a sequence of different phases is observed, starting from disordered perovskite LaCoO3-x to a brownmillerite La3Co3O8-x to eventually brownmillerite La2Co2O5-x. Kinetics of the ordering and vacancy injection, as well as implications for beam-driven phase-transformation at an atomic scale, will be discussed. Research at ORNL supported by the MSE division, BES U.S. DOE, and through a user project supported by ORNL's CMMS, which is also sponsored by BES U.S. DOE.

  7. Real-time imaging of dynamic translocation of fluorescent proteins at synapses in living neurons.

    NASA Astrophysics Data System (ADS)

    De Koninck, Paul

    2003-02-01

    To understand the biology of living cells, such as the neurons in our brain, we focus on the molecular signaling interactions that proteins perform intracellularly. We have been studying the behavior of an enzyme, termed 'CaMKII', inside living neurons maintained in tissue culture. This enzyme plays a critical role in the control of synaptic transmission. Such role may involve the dynamic translocation of the enzyme at synaptic sites upon specific stimuli. To study this translocation, we use a cellular imaging technique that allows us to monitor the movement and targeting of CaMKII tagged by genetic engineering with a green fluorescent protein (GFP). We find that the enzyme translocates within seconds to synapses upon synaptic activation by neurotransmitter application. Our approach has lead to several key findings on the regulation of CaMKII translocation to the synapse and on its potential role in synaptic plasticity. However, several new advances in photonics and image analysis, which we will implement in our laboratory, will greatly help pushing the limits of our resolution of such type molecular event in living cells.

  8. An independent system for real-time dynamic multileaf collimation trajectory verification using EPID

    NASA Astrophysics Data System (ADS)

    Fuangrod, Todsaporn; Woodruff, Henry C.; Rowshanfarzad, Pejman; O'Connor, Daryl J.; Middleton, Richard H.; Greer, Peter B.

    2014-01-01

    A new tool has been developed to verify the trajectory of dynamic multileaf collimators (MLCs) used in advanced radiotherapy techniques using only the information provided by the electronic portal imaging devices (EPID) measured image frames. The prescribed leaf positions are resampled to a higher resolution in a pre-processing stage to improve the verification precision. Measured MLC positions are extracted from the EPID frames using a template matching method. A cosine similarity metric is then applied to synchronise measured and planned leaf positions for comparison. Three additional comparison functions were incorporated to ensure robust synchronisation. The MLC leaf trajectory error detection was simulated for both intensity modulated radiation therapy (IMRT) (prostate) and volumetric modulated arc therapy (VMAT) (head-and-neck) deliveries with anthropomorphic phantoms in the beam. The overall accuracy for MLC positions automatically extracted from EPID image frames was approximately 0.5 mm. The MLC leaf trajectory verification system can detect leaf position errors during IMRT and VMAT with a tolerance of 3.5 mm within 1 s.

  9. Accurate ampacity determination: Temperature-Sag Model for operational real time ratings

    SciTech Connect

    Seppa, T.O.

    1995-07-01

    This report presents a method for determining transmission line ratings based on the relationship between the conductor`s temperature and its sag. The method is based on the Ruling Span principle and the use of transmission line tension monitoring systems. The report also presents a method of accurately calibrating the final sag of the conductor and determining the actual Ruling Span length of the line sections between deadend structures. Main error sources for two other real time methods are also examined.

  10. Modelling, Simulation, Animation, and Real-Time Control (Mosart) for a Class of Electromechanical Systems: A System-Theoretic Approach

    ERIC Educational Resources Information Center

    Rodriguez, Armando A.; Metzger, Richard P.; Cifdaloz, Oguzhan; Dhirasakdanon, Thanate; Welfert, Bruno

    2004-01-01

    This paper describes an interactive modelling, simulation, animation, and real-time control (MoSART) environment for a class of 'cart-pendulum' electromechanical systems that may be used to enhance learning within differential equations and linear algebra classes. The environment is useful for conveying fundamental mathematical/systems concepts…

  11. Control-oriented modeling and real-time control for the ozone dosing process of drinking water treatment.

    PubMed

    Wang, Dongsheng; Li, Shihua; Zhou, Xingpeng

    2013-03-05

    Ozonation is one of the most important steps during drinking water treatment. To improve the efficiency of ozonation and to stabilize the quality of the treated water, control-oriented modeling and a real-time control method for the ozone dosing process are developed in this study. Compared with existing ozonation models developed by bench-scale and pilot-scale batch experiments, the model reported herein is control-oriented and based on plant-scale batch experiments. A real-time control strategy for maintaining a constant ozone exposure is attempted to meet primary disinfection requirements. An internal model control scheme is proposed to maintain a constant ozone exposure by adjusting the ozone dosage. The proposed real-time control method can cope with changing water quality, water flow rate, and process operational conditions. Both simulations and experimental studies have been carried out and implemented for the ozone dosing process control system, and the results demonstrate the effectiveness and practicality of this real-time control method.

  12. REAL-TIME MEASUREMENT OF AIRWAY RESPONSES TO SULOFUR DIOXIDE (SO2) IN AN INTACT, AWAKE GUINEA PIG MODEL

    EPA Science Inventory

    Real-time measurment of airway responses to Sulfur Dioxide (SO2) in an intact, awake guinea pig model. J Stanek1,2, Q Krantz2, J Nolan2, D Winsett2, W Watkinson2, and D Costa2. 1College of Veterinary Medicine, NCSU, Raleigh, NC, USA; 2Pulmonary Toxicology Branch, ETD, NHEERL, US...

  13. REAL-TIME MODELING AND MEASUREMENT OF MOBILE SOURCE POLLUTANT CONCENTRATIONS FOR ESTIMATING HUMAN EXPOSURES IN COMMUNITIES NEAR ROADWAYS

    EPA Science Inventory

    The United States Environmental Protection Agency's (EPA) National Exposure Research Laboratory (NERL) is pursuing a project to improve the methodology for real-time site specific modeling of human exposure to pollutants from motor vehicles. The overall project goal is to deve...

  14. Dynamic regulation of mechanosensitive channels: capacitance used to monitor patch tension in real time

    NASA Astrophysics Data System (ADS)

    Suchyna, Thomas M.; Besch, Steven R.; Sachs, Frederick

    2004-03-01

    All cells, from bacteria to human, are mechanically sensitive. The most rapid of these membrane protein transducers are mechanosensitive ion channels, ionic pores in the membrane that open and close in response to membrane tension. In specific sensory organs, these channels serve the senses of touch and hearing, and inform the central nervous system about the filling of hollow organs such as the bladder. Non-specialized cells use these channels to report on changes in cell volume and local strain. To preserve dynamic sensitivity, sensory receptors adapt to steady-state stimuli. Here we show that in rat astrocytes, the most abundant cells in the brain, this apparent adaptation to the stimulus is actually an inactivation. We have been able to track the time course of local strain by measuring attofarad changes in membrane capacitance and show that it is not correlated with loss of channel activity. The reduction in current with time is caused by an increased occupancy of low conductance states, and a reduction in the probability of opening, not a relaxation of local stress. The occupancy of these substates depends on the integrity of the cell's cytoplasm. However, while disruption of the cytoskeleton leads to a loss of inactivation, it leaves activation unaffected. The activation process is voltage-insensitive, closely correlated with changes in capacitance, and seems to arise solely from stress in the bilayer. The inactivation rate decreases with depolarization, and kinetic analysis suggests that the process involves multiple cytoplasmic ligands. Surprisingly, multivalent ions such as Gd+3 and Ca+2 that bind to the lipids and affect channel gating, do not affect the strain-induced increase in membrane capacitance; contrary to expectations, membrane elasticity is unchanged.

  15. Improving BeiDou real-time precise point positioning with numerical weather models

    NASA Astrophysics Data System (ADS)

    Lu, Cuixian; Li, Xingxing; Zus, Florian; Heinkelmann, Robert; Dick, Galina; Ge, Maorong; Wickert, Jens; Schuh, Harald

    2017-02-01

    Precise positioning with the current Chinese BeiDou Navigation Satellite System is proven to be of comparable accuracy to the Global Positioning System, which is at centimeter level for the horizontal components and sub-decimeter level for the vertical component. But the BeiDou precise point positioning (PPP) shows its limitation in requiring a relatively long convergence time. In this study, we develop a numerical weather model (NWM) augmented PPP processing algorithm to improve BeiDou precise positioning. Tropospheric delay parameters, i.e., zenith delays, mapping functions, and horizontal delay gradients, derived from short-range forecasts from the Global Forecast System of the National Centers for Environmental Prediction (NCEP) are applied into BeiDou real-time PPP. Observational data from stations that are capable of tracking the BeiDou constellation from the International GNSS Service (IGS) Multi-GNSS Experiments network are processed, with the introduced NWM-augmented PPP and the standard PPP processing. The accuracy of tropospheric delays derived from NCEP is assessed against with the IGS final tropospheric delay products. The positioning results show that an improvement in convergence time up to 60.0 and 66.7% for the east and vertical components, respectively, can be achieved with the NWM-augmented PPP solution compared to the standard PPP solutions, while only slight improvement in the solution convergence can be found for the north component. A positioning accuracy of 5.7 and 5.9 cm for the east component is achieved with the standard PPP that estimates gradients and the one that estimates no gradients, respectively, in comparison to 3.5 cm of the NWM-augmented PPP, showing an improvement of 38.6 and 40.1%. Compared to the accuracy of 3.7 and 4.1 cm for the north component derived from the two standard PPP solutions, the one of the NWM-augmented PPP solution is improved to 2.0 cm, by about 45.9 and 51.2%. The positioning accuracy for the up component

  16. Real-Time and High-Fidelity Simulation Environment for Autonomous Ground Vehicle Dynamics

    DTIC Science & Technology

    2013-08-01

    was rendered in OpenGL . Urban Environment The environment consisted of a 3D mesh model of a city. The mesh was created using a commercial tool...system. We rendered the 3D scene (in OpenGL ) and read back the depth buffer in a raster that matched the raster characteristics of a typical LIDAR...configure the simulation. Visualization is done using custom 3D graphics software based on OGRE and OpenGL . The software runs on a standard Linux

  17. Real time measurement of myocardial oxygen dynamics during cardiac ischemia-reperfusion of rats.

    PubMed

    Lee, Gi-Ja; Kim, Seung Ki; Kang, Sung Wook; Kim, Ok-Kyun; Chae, Su-Jin; Choi, Samjin; Shin, Jae Ho; Park, Hun-Kuk; Chung, Joo-Ho

    2012-11-21

    tissue injury and severity of ischemia. Therefore, quantitative measurements of oxygen tension dynamics in the myocardium would be helpful for evaluation of the cardioprotective effects of therapeutic treatments such as drug administration.

  18. Near real-time tracking of dynamic properties for standalone structural health monitoring systems

    NASA Astrophysics Data System (ADS)

    Rainieri, C.; Fabbrocino, G.; Cosenza, E.

    2011-11-01

    Automated modal parameter identification of civil engineering structures has been analyzed in a previous paper. An original algorithm, named LEONIDA, working in frequency domain, has been presented and a number of test cases have been discussed in order to point out advantages and drawbacks. It has been demonstrated that LEONIDA represents a promising and reliable tool, in particular for modal testing. Conversely, integration of such a procedure into a fully automated structural health monitoring (SHM) system has shown that it can be used as modal information engine, but length of record durations, amount of computational burden and response time lead to recognize that serious drawbacks and limitations exist for a class of applications, such as continuous monitoring of structures in seismically prone areas. In fact, a fast assessment of relevant structure health conditions in the early post-earthquake phase is becoming of interest in different European areas. In such a context, the statistical treatment of measured dynamic properties could be certainly useful, but it requires the collection of an extensive amount of local and global data in a short time. As a consequence, availability of reliable, robust and fairly fast data processing procedures for modal tracking is fundamental whenever really effective and useful SHM systems are adopted to support civil protection activities during seismic sequences. This applies mainly to strategic structures, whose health conditions must be rapidly assessed after any seismic event, in order to securely manage rescue operations. In the present paper, the main issues related to a fast, robust and reliable modal tracking for emergency management are outlined. Then, an automated modal tracking strategy for SHM applications in earthquake prone regions is described. It is based on the knowledge of the experimental mode shapes and a revised concept of spatial filtering. Results of sample applications of the proposed procedure refer

  19. Real-time global flood estimation using satellite-based precipitation and a coupled land surface and routing model

    SciTech Connect

    Wu, Huan; Adler, Robert F.; Tian, Yudong; Huffman, George J.; Li, Hongyi; Wang, JianJian

    2014-03-01

    A widely used land surface model, the Variable Infiltration Capacity (VIC) model, is coupled with a newly developed hierarchical dominant river tracing-based runoff-routing model to form the Dominant river tracing-Routing Integrated with VIC Environment (DRIVE) model, which serves as the new core of the real-time Global Flood Monitoring System (GFMS). The GFMS uses real-time satellite-based precipitation to derive flood monitoring parameters for the latitude band 50°N–50°S at relatively high spatial (~12 km) and temporal (3 hourly) resolution. Examples of model results for recent flood events are computed using the real-time GFMS (http://flood.umd.edu). To evaluate the accuracy of the new GFMS, the DRIVE model is run retrospectively for 15 years using both research-quality and real-time satellite precipitation products. Evaluation results are slightly better for the research-quality input and significantly better for longer duration events (3 day events versus 1 day events). Basins with fewer dams tend to provide lower false alarm ratios. For events longer than three days in areas with few dams, the probability of detection is ~0.9 and the false alarm ratio is ~0.6. In general, these statistical results are better than those of the previous system. Streamflow was evaluated at 1121 river gauges across the quasi-global domain. Validation using real-time precipitation across the tropics (30°S–30°N) gives positive daily Nash-Sutcliffe Coefficients for 107 out of 375 (28%) stations with a mean of 0.19 and 51% of the same gauges at monthly scale with a mean of 0.33. Finally, there were poorer results in higher latitudes, probably due to larger errors in the satellite precipitation input.

  20. Real-Time Global Flood Estimation Using Satellite-Based Precipitation and a Coupled Land Surface and Routing Model

    NASA Technical Reports Server (NTRS)

    Wu, Huan; Adler, Robert F.; Tian, Yudong; Huffman, George J.; Li, Hongyi; Wang, JianJian

    2014-01-01

    A widely used land surface model, the Variable Infiltration Capacity (VIC) model, is coupled with a newly developed hierarchical dominant river tracing-based runoff-routing model to form the Dominant river tracing-Routing Integrated with VIC Environment (DRIVE) model, which serves as the new core of the real-time Global Flood Monitoring System (GFMS). The GFMS uses real-time satellite-based precipitation to derive flood monitoring parameters for the latitude band 50 deg. N - 50 deg. S at relatively high spatial (approximately 12 km) and temporal (3 hourly) resolution. Examples of model results for recent flood events are computed using the real-time GFMS (http://flood.umd.edu). To evaluate the accuracy of the new GFMS, the DRIVE model is run retrospectively for 15 years using both research-quality and real-time satellite precipitation products. Evaluation results are slightly better for the research-quality input and significantly better for longer duration events (3 day events versus 1 day events). Basins with fewer dams tend to provide lower false alarm ratios. For events longer than three days in areas with few dams, the probability of detection is approximately 0.9 and the false alarm ratio is approximately 0.6. In general, these statistical results are better than those of the previous system. Streamflow was evaluated at 1121 river gauges across the quasi-global domain. Validation using real-time precipitation across the tropics (30 deg. S - 30 deg. N) gives positive daily Nash-Sutcliffe Coefficients for 107 out of 375 (28%) stations with a mean of 0.19 and 51% of the same gauges at monthly scale with a mean of 0.33. There were poorer results in higher latitudes, probably due to larger errors in the satellite precipitation input.

  1. Real-time simulation of power transmission lines using Marti model with optimal fitting on dual-DSP card

    SciTech Connect

    Dufour, C.; Le-Huy, H.; El Hakimi, A.; Soumagne, J.C.

    1996-01-01

    Real-time simulation of a small power network containing a Marti modeled transmission line is made using 2 parallel DSP`s. A new fitting method is used in the modeling of the Marti line which is optimized with regards to the fitting error curve. Results are presented which show the time costs of the Marti line modeling versus constant-parameter line modeling and the time savings by using two parallel DSP`s.

  2. A real time dynamic data acquisition and processing system for velocity, density, and total temperature fluctuation measurements

    NASA Technical Reports Server (NTRS)

    Clukey, Steven J.

    1991-01-01

    The real time Dynamic Data Acquisition and Processing System (DDAPS) is described which provides the capability for the simultaneous measurement of velocity, density, and total temperature fluctuations. The system of hardware and software is described in context of the wind tunnel environment. The DDAPS replaces both a recording mechanism and a separate data processing system. DDAPS receives input from hot wire anemometers. Amplifiers and filters condition the signals with computer controlled modules. The analog signals are simultaneously digitized and digitally recorded on disk. Automatic acquisition collects necessary calibration and environment data. Hot wire sensitivities are generated and applied to the hot wire data to compute fluctuations. The presentation of the raw and processed data is accomplished on demand. The interface to DDAPS is described along with the internal mechanisms of DDAPS. A summary of operations relevant to the use of the DDAPS is also provided.

  3. Real-time hybrid simulation of a complex bridge model with MR dampers using the convolution integral method

    NASA Astrophysics Data System (ADS)

    Jiang, Zhaoshuo; Jig Kim, Sung; Plude, Shelley; Christenson, Richard

    2013-10-01

    Magneto-rheological (MR) fluid dampers can be used to reduce the traffic induced vibration in highway bridges and protect critical structural components from fatigue. Experimental verification is needed to verify the applicability of the MR dampers for this purpose. Real-time hybrid simulation (RTHS), where the MR dampers are physically tested and dynamically linked to a numerical model of the highway bridge and truck traffic, provides an efficient and effective means to experimentally examine the efficacy of MR dampers for fatigue protection of highway bridges. In this paper a complex highway bridge model with 263 178 degrees-of-freedom under truck loading is tested using the proposed convolution integral (CI) method of RTHS for a semiactive structural control strategy employing two large-scale 200 kN MR dampers. The formation of RTHS using the CI method is first presented, followed by details of the various components in the RTHS and a description of the implementation of the CI method for this particular test. The experimental results confirm the practicability of the CI method for conducting RTHS of complex systems.

  4. Towards Real-Time Maneuver Detection: Automatic State and Dynamics Estimation with the Adaptive Optimal Control Based Estimator

    NASA Astrophysics Data System (ADS)

    Lubey, D.; Scheeres, D.

    Tracking objects in Earth orbit is fraught with complications. This is due to the large population of orbiting spacecraft and debris that continues to grow, passive (i.e. no direct communication) and data-sparse observations, and the presence of maneuvers and dynamics mismodeling. Accurate orbit determination in this environment requires an algorithm to capture both a system's state and its state dynamics in order to account for mismodelings. Previous studies by the authors yielded an algorithm called the Optimal Control Based Estimator (OCBE) - an algorithm that simultaneously estimates a system's state and optimal control policies that represent dynamic mismodeling in the system for an arbitrary orbit-observer setup. The stochastic properties of these estimated controls are then used to determine the presence of mismodelings (maneuver detection), as well as characterize and reconstruct the mismodelings. The purpose of this paper is to develop the OCBE into an accurate real-time orbit tracking and maneuver detection algorithm by automating the algorithm and removing its linear assumptions. This results in a nonlinear adaptive estimator. In its original form the OCBE had a parameter called the assumed dynamic uncertainty, which is selected by the user with each new measurement to reflect the level of dynamic mismodeling in the system. This human-in-the-loop approach precludes real-time application to orbit tracking problems due to their complexity. This paper focuses on the Adaptive OCBE, a version of the estimator where the assumed dynamic uncertainty is chosen automatically with each new measurement using maneuver detection results to ensure that state uncertainties are properly adjusted to account for all dynamic mismodelings. The paper also focuses on a nonlinear implementation of the estimator. Originally, the OCBE was derived from a nonlinear cost function then linearized about a nominal trajectory, which is assumed to be ballistic (i.e. the nominal optimal

  5. Using an external surrogate for predictor model training in real-time motion management of lung tumors

    SciTech Connect

    Rottmann, Joerg; Berbeco, Ross

    2014-12-15

    Purpose: Precise prediction of respiratory motion is a prerequisite for real-time motion compensation techniques such as beam, dynamic couch, or dynamic multileaf collimator tracking. Collection of tumor motion data to train the prediction model is required for most algorithms. To avoid exposure of patients to additional dose from imaging during this procedure, the feasibility of training a linear respiratory motion prediction model with an external surrogate signal is investigated and its performance benchmarked against training the model with tumor positions directly. Methods: The authors implement a lung tumor motion prediction algorithm based on linear ridge regression that is suitable to overcome system latencies up to about 300 ms. Its performance is investigated on a data set of 91 patient breathing trajectories recorded from fiducial marker tracking during radiotherapy delivery to the lung of ten patients. The expected 3D geometric error is quantified as a function of predictor lookahead time, signal sampling frequency and history vector length. Additionally, adaptive model retraining is evaluated, i.e., repeatedly updating the prediction model after initial training. Training length for this is gradually increased with incoming (internal) data availability. To assess practical feasibility model calculation times as well as various minimum data lengths for retraining are evaluated. Relative performance of model training with external surrogate motion data versus tumor motion data is evaluated. However, an internal–external motion correlation model is not utilized, i.e., prediction is solely driven by internal motion in both cases. Results: Similar prediction performance was achieved for training the model with external surrogate data versus internal (tumor motion) data. Adaptive model retraining can substantially boost performance in the case of external surrogate training while it has little impact for training with internal motion data. A minimum

  6. Draft Forecasts from Real-Time Runs of Physics-Based Models - A Road to the Future

    NASA Technical Reports Server (NTRS)

    Hesse, Michael; Rastatter, Lutz; MacNeice, Peter; Kuznetsova, Masha

    2008-01-01

    The Community Coordinated Modeling Center (CCMC) is a US inter-agency activity aiming at research in support of the generation of advanced space weather models. As one of its main functions, the CCMC provides to researchers the use of space science models, even if they are not model owners themselves. The second focus of CCMC activities is on validation and verification of space weather models, and on the transition of appropriate models to space weather forecast centers. As part of the latter activity, the CCMC develops real-time simulation systems that stress models through routine execution. A by-product of these real-time calculations is the ability to derive model products, which may be useful for space weather operators. After consultations with NOAA/SEC and with AFWA, CCMC has developed a set of tools as a first step to make real-time model output useful to forecast centers. In this presentation, we will discuss the motivation for this activity, the actions taken so far, and options for future tools from model output.

  7. Network dynamics with BrainX3: a large-scale simulation of the human brain network with real-time interaction

    PubMed Central

    Arsiwalla, Xerxes D.; Zucca, Riccardo; Betella, Alberto; Martinez, Enrique; Dalmazzo, David; Omedas, Pedro; Deco, Gustavo; Verschure, Paul F. M. J.

    2015-01-01

    BrainX3 is a large-scale simulation of human brain activity with real-time interaction, rendered in 3D in a virtual reality environment, which combines computational power with human intuition for the exploration and analysis of complex dynamical networks. We ground this simulation on structural connectivity obtained from diffusion spectrum imaging data and model it on neuronal population dynamics. Users can interact with BrainX3 in real-time by perturbing brain regions with transient stimulations to observe reverberating network activity, simulate lesion dynamics or implement network analysis functions from a library of graph theoretic measures. BrainX3 can thus be used as a novel immersive platform for exploration and analysis of dynamical activity patterns in brain networks, both at rest or in a task-related state, for discovery of signaling pathways associated to brain function and/or dysfunction and as a tool for virtual neurosurgery. Our results demonstrate these functionalities and shed insight on the dynamics of the resting-state attractor. Specifically, we found that a noisy network seems to favor a low firing attractor state. We also found that the dynamics of a noisy network is less resilient to lesions. Our simulations on TMS perturbations show that even though TMS inhibits most of the network, it also sparsely excites a few regions. This is presumably due to anti-correlations in the dynamics and suggests that even a lesioned network can show sparsely distributed increased activity compared to healthy resting-state, over specific brain areas. PMID:25759649

  8. The Elastic Body Model: A Pedagogical Approach Integrating Real Time Measurements and Modelling Activities

    ERIC Educational Resources Information Center

    Fazio, C.; Guastella, I.; Tarantino, G.

    2007-01-01

    In this paper, we describe a pedagogical approach to elastic body movement based on measurements of the contact times between a metallic rod and small bodies colliding with it and on modelling of the experimental results by using a microcomputer-based laboratory and simulation tools. The experiments and modelling activities have been built in the…

  9. A biomechanical model for real-time simulation of PMMA injection with haptics.

    PubMed

    Lian, Z; Chui, C-K; Teoh, S-H

    2008-03-01

    We have developed a computationally efficient rheological model to simulate polymethylmethacrylate (PMMA) injection into cancellous bone during percutaneous vertebroplasty. The model employs the Hagen-Poiseuille law to predict pressure drop across a delivery cannula with viscoelastic changes of curing PMMA modeled via a time and shear-rate-dependent power law. The power law was derived based on dynamic rheological testing of curing PMMA samples. In conjunction with a branching-pipe geometrical model that is reconstructed from micro-computed tomography scans of cancellous bone for estimating pressure changes during PMMA flow in bone, the method provides a fast estimation of overall injection pressure, and, hence, the reaction force during manual PMMA injection.

  10. A real-time photo-realistic rendering algorithm of ocean color based on bio-optical model

    NASA Astrophysics Data System (ADS)

    Ma, Chunyong; Xu, Shu; Wang, Hongsong; Tian, Fenglin; Chen, Ge

    2016-12-01

    A real-time photo-realistic rendering algorithm of ocean color is introduced in the paper, which considers the impact of ocean bio-optical model. The ocean bio-optical model mainly involves the phytoplankton, colored dissolved organic material (CDOM), inorganic suspended particle, etc., which have different contributions to absorption and scattering of light. We decompose the emergent light of the ocean surface into the reflected light from the sun and the sky, and the subsurface scattering light. We establish an ocean surface transmission model based on ocean bidirectional reflectance distribution function (BRDF) and the Fresnel law, and this model's outputs would be the incident light parameters of subsurface scattering. Using ocean subsurface scattering algorithm combined with bio-optical model, we compute the scattering light emergent radiation in different directions. Then, we blend the reflection of sunlight and sky light to implement the real-time ocean color rendering in graphics processing unit (GPU). Finally, we use two kinds of radiance reflectance calculated by Hydrolight radiative transfer model and our algorithm to validate the physical reality of our method, and the results show that our algorithm can achieve real-time highly realistic ocean color scenes.

  11. Retrieving of atmospheric parameters from multi-GNSS in real time: Validation with water vapor radiometer and numerical weather model

    NASA Astrophysics Data System (ADS)

    Li, Xingxing; Zus, Florian; Lu, Cuixian; Dick, Galina; Ning, Tong; Ge, Maorong; Wickert, Jens; Schuh, Harald

    2015-07-01

    The multiconstellation Global Navigation Satellite Systems (GNSS) (e.g., GPS, GLObal NAvigation Satellite System (GLONASS), Galileo, and BeiDou) offers great opportunities for real-time retrieval of atmospheric parameters for supporting numerical weather prediction nowcasting or severe weather event monitoring. In this study, the observations from different GNSS are combined to retrieve atmospheric parameters based on the real-time precise point positioning technique. The atmospheric parameters, retrieved from multi-GNSS observations of a 180 day period from about 100 globally distributed stations, including zenith total delay, integrated water vapor, horizontal gradient, and slant total delay (STD), are analyzed and evaluated. The water vapor radiometer data and a numerical weather model, the operational analysis of the European Centre for Medium-Range Weather Forecasts (ECMWF), are used to independently validate the performance of individual GNSS and also demonstrate the benefits of multiconstellation GNSS for real-time atmospheric monitoring. Our results show that the GLONASS and BeiDou have the potential capability for real-time atmospheric parameter retrieval for time-critical meteorological applications as GPS does, and the combination of multi-GNSS observations can improve the performance of a single-system solution in meteorological applications with higher accuracy and robustness. The multi-GNSS processing greatly increases the number of STDs. The mean and standard deviation of STDs between each GNSS and ECMWF exhibit a good stability as function of the elevation angle, the azimuth angle, and time, in general. An obvious latitude dependence is confirmed by a map of station specific mean and standard deviations. Such real-time atmospheric products, provided by multi-GNSS processing with higher accuracy, stronger reliability, and better distribution, might be highly valuable for atmospheric sounding systems, especially for nowcasting of extreme weather.

  12. A novel application of real-time RT-LAMP for body fluid identification: using HBB detection as the model.

    PubMed

    Su, Chih-Wen; Li, Chiao-Yun; Lee, James Chun-I; Ji, Dar-Der; Li, Shu-Ying; Daniel, Barbara; Syndercombe-Court, Denise; Linacre, Adrian; Hsieh, Hsing-Mei

    2015-06-01

    We report on a novel application of real-time reverse transcription-loop-mediated isothermal amplification (real-time RT-LAMP) to identify the presence of a specific body fluid using blood as a proof-of-concept model. By comparison with recently developed methods of body fluid identification, the RT-LAMP assay is rapid and requires only one simple heating-block maintained at a single temperature, circumventing the need for dedicated equipment. RNA was extracted from different body fluids (blood, semen, saliva, menstrual blood, sweat, and urine) for use in real-time RT-LAMP reaction. The 18S rRNA locus was used as the internal control and hemoglobin beta (HBB) as the blood-specific marker. Reverse transcription and LAMP reaction were performed in the same tube using a turbidimeter for real-time monitoring the reaction products within a threshold of 60 min. HBB LAMP products were only detected in blood and not in any of the other body fluid, but products from the 18S rRNA gene were detected in all the tested body fluids as expected. The limit of detection was a minimum of 10(-5) ng total RNA for detection of both 18S rRNA and HBB. Augmenting the detection of RT-LAMP products was performed by separation of the products using gel electrophoresis and collecting the fluorescence of calcein. The data collected indicated complete concordance with the body fluid tested regardless of the method of detection used. This is the first application of real-time RT-LAMP to detect body fluid specific RNA and indicates the use of this method in forensic biology.

  13. Real-time modelling used for outbreak management during a cholera epidemic, Haiti, 2010-2011.

    PubMed

    Abrams, J Y; Copeland, J R; Tauxe, R V; Date, K A; Belay, E D; Mody, R K; Mintz, E D

    2013-06-01

    The emergence of epidemic cholera in post-earthquake Haiti portended a public health disaster of uncertain magnitude. In order to coordinate relief efforts in an environment with limited healthcare infrastructure and stretched resources, timely and realistic projections of the extent of the cholera outbreak were crucial. Projections were shared with Government and partner organizations beginning 5 days after the first reported case and were updated using progressively more advanced methods as more surveillance data became available. The first projection estimated that 105 000 cholera cases would occur in the first year. Subsequent projections using different methods estimated up to 652 000 cases and 163 000-247 000 hospitalizations during the first year. Current surveillance data show these projections to have provided reasonable approximations of the observed epidemic. Providing the real-time projections allowed Haitian ministries and external aid organizations to better plan and implement response measures during the evolving epidemic.

  14. A Real-Time Rover Executive based On Model-Based Reactive Planning

    NASA Technical Reports Server (NTRS)

    Bias, M. Bernardine; Lemai, Solange; Muscettola, Nicola; Korsmeyer, David (Technical Monitor)

    2003-01-01

    This paper reports on the experimental verification of the ability of IDEA (Intelligent Distributed Execution Architecture) effectively operate at multiple levels of abstraction in an autonomous control system. The basic hypothesis of IDEA is that a large control system can be structured as a collection of interacting control agents, each organized around the same fundamental structure. Two IDEA agents, a system-level agent and a mission-level agent, are designed and implemented to autonomously control the K9 rover in real-time. The system is evaluated in the scenario where the rover must acquire images from a specified set of locations. The IDEA agents are responsible for enabling the rover to achieve its goals while monitoring the execution and safety of the rover and recovering from dangerous states when necessary. Experiments carried out both in simulation and on the physical rover, produced highly promising results.

  15. Real-time Non-contact Millimeter Wave Characterization of Water-Freezing and Ice-Melting Dynamics

    SciTech Connect

    Sundaram, S. K.; Woskov, Paul P.

    2008-11-12

    We applied millimeter wave radiometry for the first time to monitor water-freezing and ice-melting dynamics in real-time non-contact. The measurements were completed at a frequency of 137 GHz. Small amounts (about 2 mL) of freshwater or saltwater were frozen over a Peltier cooler and the freezing and melting sequence was recorded. Saltwater was prepared in the laboratory that contained 3.5% of table salt to simulate the ocean water. The dynamics of freezing-melting was observed by measuring the millimeter wave temperature as well as the changes in the ice or water surface reflectivity and position. This was repeated using large amounts of freshwater and saltwater (800 mL) mimicking glaciers. Millimeter wave surface level fluctuations indicated as the top surface melted, the light ice below floated up indicating lower surface temperature until the ice completely melted. Our results are useful for remote sensing and tracking temperature for potentially large-scale environmental applications, e.g., global warming.

  16. Investigating bacterial population structure and dynamics in traditional koumiss from Inner Mongolia using single molecule real-time sequencing.

    PubMed

    Gesudu, Qimu; Zheng, Yi; Xi, Xiaoxia; Hou, Qiang Chuan; Xu, Haiyan; Huang, Weiqiang; Zhang, Heping; Menghe, Bilige; Liu, Wenjun

    2016-10-01

    Koumiss is considered as a complete dairy product high in nutrients and with medicinal properties. The bacterial communities involved in production of koumiss play a crucial role in the fermentation cycle. To reveal bacterial biodiversity in koumiss and the dynamics of succession in bacterial populations during fermentation, 22 samples were collected from 5 sampling sites and the full length of the 16S ribosomal RNA genes sequenced using single molecule real-time sequencing technology. One hundred forty-eight species were identified from 82 bacterial genera and 8 phyla. These results suggested that the structural difference in the bacterial community could be attributed to geographical location. The most significant difference in bacterial composition occurred in samples from group D compared with other groups. The sampling location of group D was distant from the city and maintained the primitive local nomadic life. The dynamics of succession in bacterial communities showed that Lactobacillus helveticus increased in abundance from 0 to 9h and reached its peak at 9h and then decreased. In contrast, Enterococcus faecalis, Enterococcus durans, and Enterococcus casseliflavus increased gradually throughout the fermentation process, and reached a maximum after 24h.

  17. Parallel processing of real-time dynamic systems simulation on OSCAR (Optimally SCheduled Advanced multiprocessoR)

    NASA Technical Reports Server (NTRS)

    Kasahara, Hironori; Honda, Hiroki; Narita, Seinosuke

    1989-01-01

    Parallel processing of real-time dynamic systems simulation on a multiprocessor system named OSCAR is presented. In the simulation of dynamic systems, generally, the same calculation are repeated every time step. However, we cannot apply to Do-all or the Do-across techniques for parallel processing of the simulation since there exist data dependencies from the end of an iteration to the beginning of the next iteration and furthermore data-input and data-output are required every sampling time period. Therefore, parallelism inside the calculation required for a single time step, or a large basic block which consists of arithmetic assignment statements, must be used. In the proposed method, near fine grain tasks, each of which consists of one or more floating point operations, are generated to extract the parallelism from the calculation and assigned to processors by using optimal static scheduling at compile time in order to reduce large run time overhead caused by the use of near fine grain tasks. The practicality of the scheme is demonstrated on OSCAR (Optimally SCheduled Advanced multiprocessoR) which has been developed to extract advantageous features of static scheduling algorithms to the maximum extent.

  18. Intraoperative, Real-Time Monitoring of Blood Flow Dynamics Associated With Laser Surgery of Port Wine Stain Birthmarks

    PubMed Central

    Yang, Bruce; Yang, Owen; Guzman, John; Nguyen, Paul; Crouzet, Christian; Osann, Kathryn E.; Kelly, Kristen M.; Nelson, J. Stuart; Choi, Bernard

    2015-01-01

    Background and Objective Port-wine stain (PWS) birthmarks affect ~22 million people worldwide. After several treatment sessions, complete disappearance of the PWS occurs in only ~10% of treated patients. There is a need to develop a new strategy to improve the efficacy of each treatment session and the overall treatment outcome. The study objective was to determine how intraoperative measurements of blood flow correlate with treatment response assessed several weeks post treatment. Study Design/Materials and Methods We employed Laser Speckle Imaging (LSI) to measure intraoperative blood-flow dynamics. We collected data from 24 subjects undergoing laser therapy for facial PWS birthmarks. Photographs were taken before treatment and at a follow-up visit, and analyzed by two expert observers. Results Intraoperative LSI enables real-time monitoring of blood-flow dynamics in response to laser treatment and can inform clinicians on the need for focused re-treatment. The degree of PWS blanching achieved is positively correlated with the log-transformed acute blood-flow reduction (P =0.022). Conclusion LSI is a simple, intraoperative monitoring tool during laser therapy of PWS birthmarks. LSI provides a single value for blood flow that correlates well with the degree of blanching achieved with laser therapy. Lasers Surg. Med. PMID:26040983

  19. Real-time cosmology

    NASA Astrophysics Data System (ADS)

    Quercellini, Claudia; Amendola, Luca; Balbi, Amedeo; Cabella, Paolo; Quartin, Miguel

    2012-12-01

    In recent years, improved astrometric and spectroscopic techniques have opened the possibility of measuring the temporal change of radial and transverse position of sources in the sky over relatively short time intervals. This has made at least conceivable to establish a novel research domain, which we dub “real-time cosmology”. We review for the first time most of the work already done in this field, analysing the theoretical framework as well as some foreseeable observational strategies and their capability to constrain models. We first focus on real-time measurements of the overall redshift drift and angular separation shift in distant sources, which allows the observer to trace the background cosmic expansion and large scale anisotropy, respectively. We then examine the possibility of employing the same kind of observations to probe peculiar and proper accelerations in clustered systems, and therefore their gravitational potential. The last two sections are devoted to the future change of the cosmic microwave background on “short” time scales, as well as to the temporal shift of the temperature anisotropy power spectrum and maps. We conclude revisiting in this context the usefulness of upcoming experiments (like CODEX and Gaia) for real-time observations.

  20. A Satellite Driven Real-time Forecasting Platform in the Upper Zambezi Basin: A Multi-model Comparison

    NASA Astrophysics Data System (ADS)

    Valdes, J. B.; Wi, S.; Serrat-Capdevila, A.; Demaria, E. M.; Durcik, M.

    2015-12-01

    In large basins such as the Upper Zambezi where concentration times are of many days or even weeks, satellite precipitation products available in real-time become a key component enabling - with the use of hydrologic models - streamflow forecasts for downstream locations with enough lead time to inform decision-making. We present a real-time streamflow forecasting application based on this concept, using the TMPA and CMORPH rainfall products (which we bias-correct using the CHIRPS product) to force four distributed hydrologic models (VIC, HyMod, HBV, Sacramento) covering a variety of levels of model complexity. This study aims at establishing a multi-model satellite-based streamflow forecasting platform as a tool that can inform water management in real-time. This work is part of the efforts of the SERVIR Applied Sciences Team to bring NASA Earth Observation Applications into decision support tools for managing water resources in the Upper Zambezi, in collaboration with the Southern African Development Community Climate Services Center and the Zambezi Watercourse Commission.

  1. Modelling, Simulation, Fabrication, Experiments and Real-Time Linear State Variable Feedback Control of Cuk Converter using Pole Placement Technique

    NASA Astrophysics Data System (ADS)

    Nanda, S.; Sengupta, M.; Sengupta, A.

    2014-01-01

    Using a suitable combination of some of the basic converter topologies representing the Buck, the Boost and the Buck-Boost converters, one may obtain some other useful dc-to-dc converters. A typical example is the cascade connection of the Boost and the Buck converter which produces the well known Cuk converter. This work emphasises on the modelling, real-time simulations, fabrication and closed-loop control of a Cuk converter. For the modelling and real time simulation, FPGA platform has been used. Small signal modelling and conventional control aspects (compensator) of Cuk converter are discussed. A 200W, 10kHz Cuk converter is designed, fabricated and tested in the laboratory. The converter model is of fourth order. The transfer function being a non-minimum phase one with two right-half plane zeroes, a limited work has been done on this. For such systems, conventional control methods are demonstrated to fail. Pole placement technique, which is envisaged to be a suitable control technique for a higher order non-minimum phase system has been adopted. Excellent correlation between off-line and real-time simulation results establishes the accuracy of the work. Agreement between open-loop results obtained from the experimental set-up under steady state vis-a-vis those obtained from simulation is also a major highlight of the paper.

  2. A Microfluidic Flow Chamber Model for Platelet Transfusion and Hemostasis Measures Platelet Deposition and Fibrin Formation in Real-time.

    PubMed

    Six, Katrijn R; Devloo, Rosalie; Van Aelst, Britt; Vandekerckhove, Philippe; Feys, Hendrik B; Compernolle, Veerle

    2017-02-14

    Microfluidic models of hemostasis assess platelet function under conditions of hydrodynamic shear, but in the presence of anticoagulants, this analysis is restricted to platelet deposition only. The intricate relationship between Ca(2+)-dependent coagulation and platelet function requires careful and controlled recalcification of blood prior to analysis. Our setup uses a Y-shaped mixing channel, which supplies concentrated Ca(2+)/Mg(2+) buffer to flowing blood just prior to perfusion, enabling rapid recalcification without sample stasis. A ten-fold difference in flow velocity between both reservoirs minimizes dilution. The recalcified blood is then perfused in a collagen-coated analysis chamber, and differential labeling permits real-time imaging of both platelet and fibrin deposition using fluorescence video microscopy. The system uses only commercially available tools, increasing the chances of standardization. Reconstitution of thrombocytopenic blood with platelets from banked concentrates furthermore models platelet transfusion, proving its use in this research domain. Exemplary data demonstrated that coagulation onset and fibrin deposition were linearly dependent on the platelet concentration, confirming the relationship between primary and secondary hemostasis in our model. In a timeframe of 16 perfusion min, contact activation did not take place, despite recalcification to normal Ca(2+) and Mg(2+) levels. When coagulation factor XIIa was inhibited by corn trypsin inhibitor, this time frame was even longer, indicating a considerable dynamic range in which the changes in the procoagulant nature of the platelets can be assessed. Co-immobilization of tissue factor with collagen significantly reduced the time to onset of coagulation, but not its rate. The option to study the tissue factor and/or the contact pathway increases the versatility and utility of the assay.

  3. Couch-based motion compensation: modelling, simulation and real-time experiments

    NASA Astrophysics Data System (ADS)

    Haas, Olivier C. L.; Skworcow, Piotr; Paluszczyszyn, Daniel; Sahih, Abdelhamid; Ruta, Mariusz; Mills, John A.

    2012-09-01

    The paper presents a couch-based active motion compensation strategy evaluated in simulation and validated experimentally using both a research and a clinical Elekta Precise Table™. The control strategy combines a Kalman filter to predict the surrogate motion used as a reference by a linear model predictive controller with the control action calculation based on estimated position and velocity feedback provided by an observer as well as predicted couch position and velocity using a linearized state space model. An inversion technique is used to compensate for the dead-zone nonlinearity. New generic couch models are presented and applied to model the Elekta Precise Table™ dynamics and nonlinearities including dead zone. Couch deflection was measured for different manufacturers and found to be up to 25 mm. A feed-forward approach is proposed to compensate for such couch deflection. Simultaneous motion compensation for longitudinal, lateral and vertical motions was evaluated using arbitrary trajectories generated from sensors or loaded from files. Tracking errors were between 0.5 and 2 mm RMS. A dosimetric evaluation of the motion compensation was done using a sinusoidal waveform. No notable differences were observed between films obtained for a fixed- or motion-compensated target. Further dosimetric improvement could be made by combining gating, based on tracking error together with beam on/off time, and PSS compensation.

  4. Couch-based motion compensation: modelling, simulation and real-time experiments.

    PubMed

    Haas, Olivier C L; Skworcow, Piotr; Paluszczyszyn, Daniel; Sahih, Abdelhamid; Ruta, Mariusz; Mills, John A

    2012-09-21

    The paper presents a couch-based active motion compensation strategy evaluated in simulation and validated experimentally using both a research and a clinical Elekta Precise Table™. The control strategy combines a Kalman filter to predict the surrogate motion used as a reference by a linear model predictive controller with the control action calculation based on estimated position and velocity feedback provided by an observer as well as predicted couch position and velocity using a linearized state space model. An inversion technique is used to compensate for the dead-zone nonlinearity. New generic couch models are presented and applied to model the Elekta Precise Table™ dynamics and nonlinearities including dead zone. Couch deflection was measured for different manufacturers and found to be up to 25 mm. A feed-forward approach is proposed to compensate for such couch deflection. Simultaneous motion compensation for longitudinal, lateral and vertical motions was evaluated using arbitrary trajectories generated from sensors or loaded from files. Tracking errors were between 0.5 and 2 mm RMS. A dosimetric evaluation of the motion compensation was done using a sinusoidal waveform. No notable differences were observed between films obtained for a fixed- or motion-compensated target. Further dosimetric improvement could be made by combining gating, based on tracking error together with beam on/off time, and PSS compensation.

  5. Towards real-time communication between in vivo neurophysiological data sources and simulator-based brain biomimetic models

    PubMed Central

    Lee, Giljae; Matsunaga, Andréa; Dura-Bernal, Salvador; Zhang, Wenjie; Lytton, William W; Francis, Joseph T; Fortes, José AB

    2015-01-01

    Development of more sophisticated implantable brain-machine interface (BMI) will require both interpretation of the neurophysiological data being measured and subsequent determination of signals to be delivered back to the brain. Computational models are the heart of the machine of BMI and therefore an essential tool in both of these processes. One approach is to utilize brain biomimetic models (BMMs) to develop and instantiate these algorithms. These then must be connected as hybrid systems in order to interface the BMM with in vivo data acquisition devices and prosthetic devices. The combined system then provides a test bed for neuroprosthetic rehabilitative solutions and medical devices for the repair and enhancement of damaged brain. We propose here a computer network-based design for this purpose, detailing its internal modules and data flows. We describe a prototype implementation of the design, enabling interaction between the Plexon Multichannel Acquisition Processor (MAP) server, a commercial tool to collect signals from microelectrodes implanted in a live subject and a BMM, a NEURON-based model of sensorimotor cortex capable of controlling a virtual arm. The prototype implementation supports an online mode for real-time simulations, as well as an offline mode for data analysis and simulations without real-time constraints, and provides binning operations to discretize continuous input to the BMM and filtering operations for dealing with noise. Evaluation demonstrated that the implementation successfully delivered monkey spiking activity to the BMM through LAN environments, respecting real-time constraints. PMID:26702394

  6. Real-time interferometric monitoring and measuring of photopolymerization based stereolithographic additive manufacturing process: sensor model and algorithm

    NASA Astrophysics Data System (ADS)

    Zhao, X.; Rosen, D. W.

    2017-01-01

    As additive manufacturing is poised for growth and innovations, it faces barriers of lack of in-process metrology and control to advance into wider industry applications. The exposure controlled projection lithography (ECPL) is a layerless mask-projection stereolithographic additive manufacturing process, in which parts are fabricated from photopolymers on a stationary transparent substrate. To improve the process accuracy with closed-loop control for ECPL, this paper develops an interferometric curing monitoring and measuring (ICM&M) method which addresses the sensor modeling and algorithms issues. A physical sensor model for ICM&M is derived based on interference optics utilizing the concept of instantaneous frequency. The associated calibration procedure is outlined for ICM&M measurement accuracy. To solve the sensor model, particularly in real time, an online evolutionary parameter estimation algorithm is developed adopting moving horizon exponentially weighted Fourier curve fitting and numerical integration. As a preliminary validation, simulated real-time measurement by offline analysis of a video of interferograms acquired in the ECPL process is presented. The agreement between the cured height estimated by ICM&M and that measured by microscope indicates that the measurement principle is promising as real-time metrology for global measurement and control of the ECPL process.

  7. Binary versus non-binary information in real time series: empirical results and maximum-entropy matrix models

    NASA Astrophysics Data System (ADS)

    Almog, Assaf; Garlaschelli, Diego

    2014-09-01

    The dynamics of complex systems, from financial markets to the brain, can be monitored in terms of multiple time series of activity of the constituent units, such as stocks or neurons, respectively. While the main focus of time series analysis is on the magnitude of temporal increments, a significant piece of information is encoded into the binary projection (i.e. the sign) of such increments. In this paper we provide further evidence of this by showing strong nonlinear relations between binary and non-binary properties of financial time series. These relations are a novel quantification of the fact that extreme price increments occur more often when most stocks move in the same direction. We then introduce an information-theoretic approach to the analysis of the binary signature of single and multiple time series. Through the definition of maximum-entropy ensembles of binary matrices and their mapping to spin models in statistical physics, we quantify the information encoded into the simplest binary properties of real time series and identify the most informative property given a set of measurements. Our formalism is able to accurately replicate, and mathematically characterize, the observed binary/non-binary relations. We also obtain a phase diagram allowing us to identify, based only on the instantaneous aggregate return of a set of multiple time series, a regime where the so-called ‘market mode’ has an optimal interpretation in terms of collective (endogenous) effects, a regime where it is parsimoniously explained by pure noise, and a regime where it can be regarded as a combination of endogenous and exogenous factors. Our approach allows us to connect spin models, simple stochastic processes, and ensembles of time series inferred from partial information.

  8. Real-time solution of linear computational problems using databases of parametric reduced-order models with arbitrary underlying meshes

    NASA Astrophysics Data System (ADS)

    Amsallem, David; Tezaur, Radek; Farhat, Charbel

    2016-12-01

    A comprehensive approach for real-time computations using a database of parametric, linear, projection-based reduced-order models (ROMs) based on arbitrary underlying meshes is proposed. In the offline phase of this approach, the parameter space is sampled and linear ROMs defined by linear reduced operators are pre-computed at the sampled parameter points and stored. Then, these operators and associated ROMs are transformed into counterparts that satisfy a certain notion of consistency. In the online phase of this approach, a linear ROM is constructed in real-time at a queried but unsampled parameter point by interpolating the pre-computed linear reduced operators on matrix manifolds and therefore computing an interpolated linear ROM. The proposed overall model reduction framework is illustrated with two applications: a parametric inverse acoustic scattering problem associated with a mockup submarine, and a parametric flutter prediction problem associated with a wing-tank system. The second application is implemented on a mobile device, illustrating the capability of the proposed computational framework to operate in real-time.

  9. Lipid tethering of breast tumor cells enables real-time imaging of free-floating cell dynamics and drug response

    PubMed Central

    Whipple, Rebecca A.; Zhang, Peipei; Sooklal, Elisabeth L.; Martin, Stuart S.; Jewell, Christopher M.

    2016-01-01

    Free-floating tumor cells located in the blood of cancer patients, known as circulating tumor cells (CTCs), have become key targets for studying metastasis. However, effective strategies to study the free-floating behavior of tumor cells in vitro have been a major barrier limiting the understanding of the functional properties of CTCs. Upon extracellular-matrix (ECM) detachment, breast tumor cells form tubulin-based protrusions known as microtentacles (McTNs) that play a role in the aggregation and re-attachment of tumor cells to increase their metastatic efficiency. In this study, we have designed a strategy to spatially immobilize ECM-detached tumor cells while maintaining their free-floating character. We use polyelectrolyte multilayers deposited on microfluidic substrates to prevent tumor cell adhesion and the addition of lipid moieties to tether tumor cells to these surfaces through interactions with the cell membranes. This coating remains optically clear, allowing capture of high-resolution images and videos of McTNs on viable free-floating cells. In addition, we show that tethering allows for the real-time analysis of McTN dynamics on individual tumor cells and in response to tubulin-targeting drugs. The ability to image detached tumor cells can vastly enhance our understanding of CTCs under conditions that better recapitulate the microenvironments they encounter during metastasis. PMID:26871289

  10. Real-time pressure monitoring for dynamic control during paper mill operation using fiber optic pressure sensors

    NASA Astrophysics Data System (ADS)

    Fielder, Robert S.; Boyd, Clark; Palmer, Matthew; Eriksen, Oddbjørn

    2006-03-01

    Fiber optic pressure sensors were integrated into the grinding plates of an operational paper pulp mill for real-time monitoring of the pulp grinding process. On-line system monitoring will allow smart, active control of the grinding plates thereby improving the quality and consistency of the pulp produced. Sensors were constructed and calibrated for use in the harsh environment of an operating paper pulp grinder. The sensors were 1.65mm in diameter including titanium housing, and were installed directly into the grooves of the grinding plates. The sensing elements were flush-mounted with the wall and exposed to the wood pulp slurry. Nine sensors were calibrated up to 1000psi. During operation, pressure was sampled at 1.0MHz, and pressure spikes up to 175psi were observed. Pressure pulses measured are due to the relative motion between the grooves and channels on two pulp grinding plates. The consistency, size distribution, and quality of paper pulp exiting from the grinder are directly related to the distance between the channels on the two rotating elements. The pressure pulses produced are also proportional to the distance between channels. Therefore, by monitoring pressure fluctuations, grinding elements can be dynamically controlled thereby producing a "smart mill."

  11. Dynamic resource allocation engine for cloud-based real-time video transcoding in mobile cloud computing environments

    NASA Astrophysics Data System (ADS)

    Adedayo, Bada; Wang, Qi; Alcaraz Calero, Jose M.; Grecos, Christos

    2015-02-01

    The recent explosion in video-related Internet traffic has been driven by the widespread use of smart mobile devices, particularly smartphones with advanced cameras that are able to record high-quality videos. Although many of these devices offer the facility to record videos at different spatial and temporal resolutions, primarily with local storage considerations in mind, most users only ever use the highest quality settings. The vast majority of these devices are optimised for compressing the acquired video using a single built-in codec and have neither the computational resources nor battery reserves to transcode the video to alternative formats. This paper proposes a new low-complexity dynamic resource allocation engine for cloud-based video transcoding services that are both scalable and capable of being delivered in real-time. Firstly, through extensive experimentation, we establish resource requirement benchmarks for a wide range of transcoding tasks. The set of tasks investigated covers the most widely used input formats (encoder type, resolution, amount of motion and frame rate) associated with mobile devices and the most popular output formats derived from a comprehensive set of use cases, e.g. a mobile news reporter directly transmitting videos to the TV audience of various video format requirements, with minimal usage of resources both at the reporter's end and at the cloud infrastructure end for transcoding services.

  12. Continuous real-time photoacoustic demodulation via field programmable gate array for dynamic imaging of zebrafish cardiac cycle.

    PubMed

    Mattison, Scott P; Shelton, Ryan L; Maxson, Ryan T; Applegate, Brian E

    2013-01-01

    A four dimensional data set of the cardiac cycle of a zebrafish embryo was acquired using postacquisition synchronization of real time photoacoustic b-scans. Utilizing an off-axis photoacoustic microscopy (OA-PAM) setup, we have expanded upon our previous work with OA-PAM to develop a system that can sustain 100 kHz line rates while demodulating the bipolar photoacoustic signal in real-time. Real-time processing was accomplished by quadrature demodulation on a Field Programmable Gate Array (FPGA) in line with the signal digitizer. Simulated data acquisition verified the system is capable of real-time processing up to a line rate of 1 MHz. Galvanometer-scanning of the excitation laser inside the focus of the ultrasonic transducer enables real data acquisition of a 200 by 200 by 200 pixel, volumetric data set across a 2 millimeter field of view at a rate of 2.5 Hz.

  13. Processor core for real time background identification of HD video based on OpenCV Gaussian mixture model algorithm

    NASA Astrophysics Data System (ADS)

    Genovese, Mariangela; Napoli, Ettore

    2013-05-01

    The identification of moving objects is a fundamental step in computer vision processing chains. The development of low cost and lightweight smart cameras steadily increases the request of efficient and high performance circuits able to process high definition video in real time. The paper proposes two processor cores aimed to perform the real time background identification on High Definition (HD, 1920 1080 pixel) video streams. The implemented algorithm is the OpenCV version of the Gaussian Mixture Model (GMM), an high performance probabilistic algorithm for the segmentation of the background that is however computationally intensive and impossible to implement on general purpose CPU with the constraint of real time processing. In the proposed paper, the equations of the OpenCV GMM algorithm are optimized in such a way that a lightweight and low power implementation of the algorithm is obtained. The reported performances are also the result of the use of state of the art truncated binary multipliers and ROM compression techniques for the implementation of the non-linear functions. The first circuit has commercial FPGA devices as a target and provides speed and logic resource occupation that overcome previously proposed implementations. The second circuit is oriented to an ASIC (UMC-90nm) standard cell implementation. Both implementations are able to process more than 60 frames per second in 1080p format, a frame rate compatible with HD television.

  14. A real-time recording model of key indicators for energy consumption and carbon emissions of sustainable buildings.

    PubMed

    Wu, Weiwei; Yang, Huanjia; Chew, David; Hou, Yanhong; Li, Qiming

    2014-05-14

    Buildings' sustainability is one of the crucial parts for achieving urban sustainability. Applied to buildings, life-cycle assessment encompasses the analysis and assessment of the environmental effects of building materials, components and assemblies throughout the entire life of the building construction, use and demolition. Estimate of carbon emissions is essential and crucial for an accurate and reasonable life-cycle assessment. Addressing the need for more research into integrating analysis of real-time and automatic recording of key indicators for a more accurate calculation and comparison, this paper aims to design a real-time recording model of these crucial indicators concerning the calculation and estimation of energy use and carbon emissions of buildings based on a Radio Frequency Identification (RFID)-based system. The architecture of the RFID-based carbon emission recording/tracking system, which contains four functional layers including data record layer, data collection/update layer, data aggregation layer and data sharing/backup layer, is presented. Each of these layers is formed by RFID or network devices and sub-systems that operate at a specific level. In the end, a proof-of-concept system is developed to illustrate the implementation of the proposed architecture and demonstrate the feasibility of the design. This study would provide the technical solution for real-time recording system of building carbon emissions and thus is of great significance and importance to improve urban sustainability.

  15. A Real-Time Recording Model of Key Indicators for Energy Consumption and Carbon Emissions of Sustainable Buildings

    PubMed Central

    Wu, Weiwei; Yang, Huanjia; Chew, David; Hou, Yanhong; Li, Qiming

    2014-01-01

    Buildings' sustainability is one of the crucial parts for achieving urban sustainability. Applied to buildings, life-cycle assessment encompasses the analysis and assessment of the environmental effects of building materials, components and assemblies throughout the entire life of the building construction, use and demolition. Estimate of carbon emissions is essential and crucial for an accurate and reasonable life-cycle assessment. Addressing the need for more research into integrating analysis of real-time and automatic recording of key indicators for a more accurate calculation and comparison, this paper aims to design a real-time recording model of these crucial indicators concerning the calculation and estimation of energy use and carbon emissions of buildings based on a Radio Frequency Identification (RFID)-based system. The architecture of the RFID-based carbon emission recording/tracking system, which contains four functional layers including data record layer, data collection/update layer, data aggregation layer and data sharing/backup layer, is presented. Each of these layers is formed by RFID or network devices and sub-systems that operate at a specific level. In the end, a proof-of-concept system is developed to illustrate the implementation of the proposed architecture and demonstrate the feasibility of the design. This study would provide the technical solution for real-time recording system of building carbon emissions and thus is of great significance and importance to improve urban sustainability. PMID:24831109

  16. Automated system for near-real time modelling and prediction of altimeter-derived sea level anomalies

    NASA Astrophysics Data System (ADS)

    Niedzielski, Tomasz; Miziński, Bartłomiej

    2013-08-01

    This paper serves as a presentation of a novel geoinformation system and a dedicated service, jointly named as Prognocean and based at the University of Wrocław (Poland), that aim to predict Sea Level Anomaly (SLA) maps and publish them online. The system works in near-real time and is updated daily. The data are provided by the Archiving, Validation and Interpretation of Satellite Oceanographic data (AVISO), and the time series processed by Prognocean is delivered by various altimetric satellites. The emphasis is put on gridded SLA maps, also known as MSLA, which are provided as Delayed Time (DT) and Near-Real Time (NRT) daily products. The daily sampling interval, however, does not coincide with typical repeat cycles of altimetric satellites and is obtained through reprocessing produced by AVISO. The two-module infrastructure forms the system. The first module is responsible for the near-real time communication with AVISO to download the most recent MSLA data and acquire the corrected data when the geophysical corrections have been available. The second module forms the main engine which does data processing, modelling, forecasting, statistical quality control and finally generates products as maps. The online service, however, publishes the products online every day. The above-mentioned components and infrastructure are described in detail. The performance of the system was evaluated using at least 150 predicted MSLA maps, available after half year of computations carried out in near-real time. We identified a few regions of imperfect performance of our prognoses and found that they spatially correspond to the mouth of the Amazon River and locations of key mesoscale eddies, the vast majority of which being nonlinear and hence unmodelled in our experiment.

  17. Real-time in vivo imaging of butterfly wing development: revealing the cellular dynamics of the pupal wing tissue.

    PubMed

    Iwata, Masaki; Ohno, Yoshikazu; Otaki, Joji M

    2014-01-01

    Butterfly wings are covered with regularly arranged single-colored scales that are formed at the pupal stage. Understanding pupal wing development is therefore crucial to understand wing color pattern formation. Here, we successfully employed real-time in vivo imaging techniques to observe pupal hindwing development over time in the blue pansy butterfly, Junonia orithya. A transparent sheet of epithelial cells that were not yet regularly arranged was observed immediately after pupation. Bright-field imaging and autofluorescent imaging revealed free-moving hemocytes and tracheal branches of a crinoid-like structure underneath the epithelium. The wing tissue gradually became gray-white, epithelial cells were arranged regularly, and hemocytes disappeared, except in the bordering lacuna, after which scales grew. The dynamics of the epithelial cells and scale growth were also confirmed by fluorescent imaging. Fluorescent in vivo staining further revealed that these cells harbored many mitochondria at the surface of the epithelium. Organizing centers for the border symmetry system were apparent immediately after pupation, exhibiting a relatively dark optical character following treatment with fluorescent dyes, as well as in autofluorescent images. The wing tissue exhibited slow and low-frequency contraction pulses with a cycle of approximately 10 to 20 minutes, mainly occurring at 2 to 3 days postpupation. The pulses gradually became slower and weaker and eventually stopped. The wing tissue area became larger after contraction, which also coincided with an increase in the autofluorescence intensity that might have been caused by scale growth. Examination of the pattern of color development revealed that the black pigment was first deposited in patches in the central areas of an eyespot black ring and a parafocal element. These results of live in vivo imaging that covered wide wing area for a long time can serve as a foundation for studying the cellular dynamics of living

  18. Real-Time In Vivo Imaging of Butterfly Wing Development: Revealing the Cellular Dynamics of the Pupal Wing Tissue

    PubMed Central

    Iwata, Masaki; Ohno, Yoshikazu; Otaki, Joji M.

    2014-01-01

    Butterfly wings are covered with regularly arranged single-colored scales that are formed at the pupal stage. Understanding pupal wing development is therefore crucial to understand wing color pattern formation. Here, we successfully employed real-time in vivo imaging techniques to observe pupal hindwing development over time in the blue pansy butterfly, Junonia orithya. A transparent sheet of epithelial cells that were not yet regularly arranged was observed immediately after pupation. Bright-field imaging and autofluorescent imaging revealed free-moving hemocytes and tracheal branches of a crinoid-like structure underneath the epithelium. The wing tissue gradually became gray-white, epithelial cells were arranged regularly, and hemocytes disappeared, except in the bordering lacuna, after which scales grew. The dynamics of the epithelial cells and scale growth were also confirmed by fluorescent imaging. Fluorescent in vivo staining further revealed that these cells harbored many mitochondria at the surface of the epithelium. Organizing centers for the border symmetry system were apparent immediately after pupation, exhibiting a relatively dark optical character following treatment with fluorescent dyes, as well as in autofluorescent images. The wing tissue exhibited slow and low-frequency contraction pulses with a cycle of approximately 10 to 20 minutes, mainly occurring at 2 to 3 days postpupation. The pulses gradually became slower and weaker and eventually stopped. The wing tissue area became larger after contraction, which also coincided with an increase in the autofluorescence intensity that might have been caused by scale growth. Examination of the pattern of color development revealed that the black pigment was first deposited in patches in the central areas of an eyespot black ring and a parafocal element. These results of live in vivo imaging that covered wide wing area for a long time can serve as a foundation for studying the cellular dynamics of living

  19. Continuous piecewise-linear, reduced-order electrochemical model for lithium-ion batteries in real-time applications

    NASA Astrophysics Data System (ADS)

    Farag, Mohammed; Fleckenstein, Matthias; Habibi, Saeid

    2017-02-01

    Model-order reduction and minimization of the CPU run-time while maintaining the model accuracy are critical requirements for real-time implementation of lithium-ion electrochemical battery models. In this paper, an isothermal, continuous, piecewise-linear, electrode-average model is developed by using an optimal knot placement technique. The proposed model reduces the univariate nonlinear function of the electrode's open circuit potential dependence on the state of charge to continuous piecewise regions. The parameterization experiments were chosen to provide a trade-off between extensive experimental characterization techniques and purely identifying all parameters using optimization techniques. The model is then parameterized in each continuous, piecewise-linear, region. Applying the proposed technique cuts down the CPU run-time by around 20%, compared to the reduced-order, electrode-average model. Finally, the model validation against real-time driving profiles (FTP-72, WLTP) demonstrates the ability of the model to predict the cell voltage accurately with less than 2% error.

  20. A Real-Time Mathematical Model for the Two-Dimensional Temperature Field of Petroleum Coke Calcination in Vertical Shaft Calciner

    NASA Astrophysics Data System (ADS)

    Xiao, Jin; Huang, Jindi; Zhong, Qifan; Li, Fachuang; Zhang, Hongliang; Li, Jie

    2016-08-01

    A real-time mathematical model for the two-dimensional temperature field of petroleum coke calcination in vertical shaft calciner was developed based on computational fluid dynamics. In the modeling process, the petroleum coke discharging process was described by the solid viscous flow, the dynamic heat flux boundary condition was adopted to specify the heat transfer between the flue wall and the gas in the flue, and the Arrhenius equation was used to characterize the pyrolysis process of petroleum coke. The model was validated with both measurement data and data from the literature. The effects of discharge rate per pot, volatile content of green coke, and excess air coefficient on the temperature field of the vertical shaft calciner were investigated with the use of the developed model. The following reasonable operating conditions were obtained: the discharge rate per pot should be less than 90 kg/h, the volatile content of green coke should be in the range of 9-11%, and the excess air coefficient should be in the range of 1.10-1.20. In this work, the governing equations were discretized by using the finite volume method, and the discrete linear equations were solved by using sparse matrix package UMFPACK. The model calculating process takes about less than 15 s. Therefore, the model is beneficial in realizing real-time online temperature detection of petroleum coke calcination in a vertical shaft calciner.

  1. Plasma models for real-time control of advanced tokamak scenarios

    NASA Astrophysics Data System (ADS)

    Moreau, D.; Mazon, D.; Walker, M. L.; Ferron, J. R.; Burrell, K. H.; Flanagan, S. M.; Gohil, P.; Groebner, R. J.; Hyatt, A. W.; La Haye, R. J.; Lohr, J.; Turco, F.; Schuster, E.; Ou, Y.; Xu, C.; Takase, Y.; Sakamoto, Y.; Ide, S.; Suzuki, T.; ITPA-IOS Group members; experts

    2011-06-01

    An integrated plasma profile control strategy, ARTAEMIS, is being developed for extrapolating present-day advanced tokamak (AT) scenarios to steady-state operation. The approach is based on semi-empirical modelling and was initially explored on JET (Moreau et al 2008 Nucl. Fusion 48 106001). This paper deals with the general applicability of this strategy for simultaneous magnetic and kinetic control on various tokamaks. The determination of the device-specific, control-oriented models that are needed to compute optimal controller matrices for a given operation scenario is discussed. The methodology is generic and can be applied to any device, with different sets of heating and current drive actuators, controlled variables and profiles. The system identification algorithms take advantage of the large ratio between the magnetic and thermal diffusion time scales and have been recently applied to both JT-60U and DIII-D data. On JT-60U, an existing series of high bootstrap current (~70%), 0.9 MA non-inductive AT discharges was used. The actuators consisted of four groups of neutral beam injectors aimed at perpendicular injection (on-axis and off-axis), and co-current tangential injection (also on-axis and off-axis). On DIII-D, dedicated system identification experiments were carried out in the loop voltage (Vext) control mode (as opposed to current control) to avoid feedback in the response data from the primary circuit. The reference plasma state was that of a 0.9 MA AT scenario which had been optimized to combine non-inductive current fractions near unity with 3.5 < βN < 3.9, bootstrap current fractions larger than 65% and H98(y,2) = 1.5. Actuators other than Vext were co-current, counter-current and balanced neutral beam injection, and electron cyclotron current drive. Power and loop voltage modulations resulted in dynamic variations of the plasma current between 0.7 and 1.2 MA. It is concluded that the response of essential plasma parameter profiles to specific

  2. The Stomatogastric Nervous System as a Model for Studying Sensorimotor Interactions in Real-Time Closed-Loop Conditions

    PubMed Central

    Daur, Nelly; Diehl, Florian; Mader, Wolfgang; Stein, Wolfgang

    2012-01-01

    The perception of proprioceptive signals that report the internal state of the body is one of the essential tasks of the nervous system and helps to continuously adapt body movements to changing circumstances. Despite the impact of proprioceptive feedback on motor activity it has rarely been studied in conditions in which motor output and sensory activity interact as they do in behaving animals, i.e., in closed-loop conditions. The interaction of motor and sensory activities, however, can create emergent properties that may govern the functional characteristics of the system. We here demonstrate a method to use a well-characterized model system for central pattern generation, the stomatogastric nervous system, for studying these properties in vitro. We created a real-time computer model of a single-cell muscle tendon organ in the gastric mill of the crab foregut that uses intracellular current injections to control the activity of the biological proprioceptor. The resulting motor output of a gastric mill motor neuron is then recorded intracellularly and fed into a simple muscle model consisting of a series of low-pass filters. The muscle output is used to activate a one-dimensional Hodgkin–Huxley type model of the muscle tendon organ in real-time, allowing closed-loop conditions. Model properties were either hand tuned to achieve the best match with data from semi-intact muscle preparations, or an exhaustive search was performed to determine the best set of parameters. We report the real-time capabilities of our models, its performance and its interaction with the biological motor system. PMID:22435059

  3. Ultrasound simulation of real-time temperature estimation during radiofrequency ablation using finite element models.

    PubMed

    Daniels, M J; Jiang, J; Varghese, T

    2008-03-01

    Radiofrequency ablation is the most common minimally invasive therapy used in the United States to treat hepatocellular carcinoma and liver metastases. The ability to perform real-time temperature imaging while a patient is undergoing ablation therapy may help reduce the high recurrence rates following ablation therapy. Ultrasound echo signals undergo time shifts with increasing temperature due to sound speed and thermal expansion, which are tracked using both 1D cross correlation and 2D block matching based speckle tracking methods. In this paper, we present a quantitative evaluation of the accuracy and precision of temperature estimation using the above algorithms on both simulated and experimental data. A finite element analysis simulation of radiofrequency ablation of hepatic tissue was developed. Finite element analysis provides a method to obtain the exact temperature distribution along with a mapping of the tissue displacement due to thermal expansion. These local displacement maps were combined with the displacement due to speed of sound changes and utilized to generate ultrasound radiofrequency frames at specified time increments over the entire ablation procedure. These echo signals provide an ideal test-bed to evaluate the performance of both speckle tracking methods, since the estimated temperature results can be compared directly to the exact finite element solution. Our results indicate that the 1D cross-correlation (CC) method underestimates the cumulative displacement by 0.20mm, while the underestimation with 2D block matching (BM) is about 0.14 mm after 360 s of ablation. The 1D method also overestimates the size of the ablated region by 5.4% when compared to 2.4% with the 2D method after 720 s of ablation. Hence 2D block matching provides better tracking of temperature variations when compared to the 1D cross-correlation method over the entire duration of the ablation procedure. In addition, results obtained using 1D cross-correlation diverge from

  4. Probability of real-time detection versus probability of infection for aerosolized biowarfare agents: a model study.

    PubMed

    Sabelnikov, Alexander; Zhukov, Vladimir; Kempf, Ruth

    2006-05-15

    Real-time biosensors are expected to provide significant help in emergency response management should a terrorist attack with the use of biowarfare, BW, agents occur. In spite of recent and spectacular progress in the field of biosensors, several core questions still remain unaddressed. For instance, how sensitive should be a sensor? To what levels of infection would the different sensitivity limits correspond? How the probabilities of identification correspond to the probabilities of infection by an agent? In this paper, an attempt was made to address these questions. A simple probability model was generated for the calculation of risks of infection of humans exposed to different doses of infectious agents and of the probability of their simultaneous real-time detection/identification by a model biosensor and its network. A model biosensor was defined as a single device that included an aerosol sampler and a device for identification by any known (or conceived) method. A network of biosensors was defined as a set of several single biosensors that operated in a similar way and dealt with the same amount of an agent. Neither the particular deployment of sensors within the network, nor the spacious and timely distribution of agent aerosols due to wind, ventilation, humidity, temperature, etc., was considered by the model. Three model biosensors based on PCR-, antibody/antigen-, and MS-technique were used for simulation. A wide range of their metric parameters encompassing those of commercially available and laboratory biosensors, and those of future, theoretically conceivable devices was used for several hundred simulations. Based on the analysis of the obtained results, it is concluded that small concentrations of aerosolized agents that are still able to provide significant risks of infection especially for highly infectious agents (e.g. for small pox those risk are 1, 8, and 37 infected out of 1000 exposed, depending on the viability of the virus preparation) will

  5. Bayesian Algorithm Implementation in a Real Time Exposure Assessment Model on Benzene with Calculation of Associated Cancer Risks

    PubMed Central

    Sarigiannis, Dimosthenis A.; Karakitsios, Spyros P.; Gotti, Alberto; Papaloukas, Costas L.; Kassomenos, Pavlos A.; Pilidis, Georgios A.

    2009-01-01

    The objective of the current study was the development of a reliable modeling platform to calculate in real time the personal exposure and the associated health risk for filling station employees evaluating current environmental parameters (traffic, meteorological and amount of fuel traded) determined by the appropriate sensor network. A set of Artificial Neural Networks (ANNs) was developed to predict benzene exposure pattern for the filling station employees. Furthermore, a Physiology Based Pharmaco-Kinetic (PBPK) risk assessment model was developed in order to calculate the lifetime probability distribution of leukemia to the employees, fed by data obtained by the ANN model. Bayesian algorithm was involved in crucial points of both model sub compartments. The application was evaluated in two filling stations (one urban and one rural). Among several algorithms available for the development of the ANN exposure model, Bayesian regularization provided the best results and seemed to be a promising technique for prediction of the exposure pattern of that occupational population group. On assessing the estimated leukemia risk under the scope of providing a distribution curve based on the exposure levels and the different susceptibility of the population, the Bayesian algorithm was a prerequisite of the Monte Carlo approach, which is integrated in the PBPK-based risk model. In conclusion, the modeling system described herein is capable of exploiting the information collected by the environmental sensors in order to estimate in real time the personal exposure and the resulting health risk for employees of gasoline filling stations. PMID:22399936

  6. Interactions of Calcium Fluctuations during Cardiomyocyte Contraction with Real-Time cAMP Dynamics Detected by FRET

    PubMed Central

    Sprenger, Julia U.; Bork, Nadja I.; Herting, Jonas; Fischer, Thomas H.; Nikolaev, Viacheslav O.

    2016-01-01

    Calcium (Ca2+) and 3’,5’-cyclic adenosine monophosphate (cAMP) play a critical role for cardiac excitation-contraction-coupling. Both second messengers are known to interact with each other, for example via Ca2+-dependent modulation of phosphodiesterase 1 (PDE1) and adenylyl cyclase 5/6 (AC 5/6) activities, which is supposed to occur especially at the local level in distinct subcellular microdomains. Currently, many studies analyze global and local cAMP signaling and its regulation in resting cardiomyocytes devoid of electrical stimulation. For example, Förster resonance energy transfer (FRET) microscopy is a popular approach for visualization of real time cAMP dynamics performed in resting cardiomyocytes to avoid potential contractility-related movement artifacts. However, it is unknown whether such data are comparable with the cell behavior under more physiologically relevant conditions during contraction. Here, we directly compare the cAMP-FRET responses to AC stimulation and PDE inhibition in resting vs. paced adult mouse ventricular cardiomyocytes for both cytosolic and subsarcolemmal microdomains. Interestingly, no significant differences in cAMP dynamics could be detected after β-adrenergic (isoproterenol) stimulation, suggesting low impact of rapidly changing contractile Ca2+ concentrations on cytosolic cAMP levels associated with AC activation. However, the contribution of the calcium-dependent PDE1, but not of the Ca2+-insensitive PDE4, to the regulation of cAMP levels after forskolin stimulation was significantly increased. This increase could be mimicked by pretreatment of resting cells with Ca2+ elevating agents. Ca2+ imaging demonstrated significantly higher amplitudes of Ca2+ transients in forskolin than in isoproterenol stimulated cells, suggesting that forskolin stimulation might lead to stronger activation of PDE1. In conclusion, changes in intracellular Ca2+ during cardiomyocyte contraction dynamically interact with cAMP levels, especially

  7. Real-time digital holographic interferometry set-up for phase gradient study in dynamic phase objects using spatial modulator

    NASA Astrophysics Data System (ADS)

    Sima, Adrian; Schiopu, Paul; Logofatu, Petre C.

    2016-12-01

    A fully digital experimental set-up for real-time digital acquisition and digital optical reconstruction of holographic sequences is presented: a He-Ne laser, a CCD camera and a Phase Only Spatial Light Modulator (SLM) area are part of the set-up. CCD registering and SLM projector are working simultaneously. Using a custom made software of our own, real-time Digital Holographic Interferometry (DHI) "fringe motion pictures" can be performed by subtracting consecutive frames from a reference one and instantly displaying the differences on the SLM illuminated with a playback wave. Phase variations of the objects can be visualized in real-time by observing the interference fringe pattern evolution.

  8. Real-Time Kennedy Space Center and Cape Canaveral Air Force Station High-Resolution Model Implementation and Verification

    NASA Technical Reports Server (NTRS)

    Shafer, Jaclyn; Watson, Leela R.

    2015-01-01

    NASA's Launch Services Program, Ground Systems Development and Operations, Space Launch System and other programs at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) use the daily and weekly weather forecasts issued by the 45th Weather Squadron (45 WS) as decision tools for their day-to-day and launch operations on the Eastern Range (ER). Examples include determining if they need to limit activities such as vehicle transport to the launch pad, protect people, structures or exposed launch vehicles given a threat of severe weather, or reschedule other critical operations. The 45 WS uses numerical weather prediction models as a guide for these weather forecasts, particularly the Air Force Weather Agency (AFWA) 1.67 km Weather Research and Forecasting (WRF) model. Considering the 45 WS forecasters' and Launch Weather Officers' (LWO) extensive use of the AFWA model, the 45 WS proposed a task at the September 2013 Applied Meteorology Unit (AMU) Tasking Meeting requesting the AMU verify this model. Due to the lack of archived model data available from AFWA, verification is not yet possible. Instead, the AMU proposed to implement and verify the performance of an ER version of the high-resolution WRF Environmental Modeling System (EMS) model configured by the AMU (Watson 2013) in real time. Implementing a real-time version of the ER WRF-EMS would generate a larger database of model output than in the previous AMU task for determining model performance, and allows the AMU more control over and access to the model output archive. The tasking group agreed to this proposal; therefore the AMU implemented the WRF-EMS model on the second of two NASA AMU modeling clusters. The AMU also calculated verification statistics to determine model performance compared to observational data. Finally, the AMU made the model output available on the AMU Advanced Weather Interactive Processing System II (AWIPS II) servers, which allows the 45 WS and AMU staff to customize

  9. Real-time flutter identification

    NASA Technical Reports Server (NTRS)

    Roy, R.; Walker, R.

    1985-01-01

    The techniques and a FORTRAN 77 MOdal Parameter IDentification (MOPID) computer program developed for identification of the frequencies and damping ratios of multiple flutter modes in real time are documented. Physically meaningful model parameterization was combined with state of the art recursive identification techniques and applied to the problem of real time flutter mode monitoring. The performance of the algorithm in terms of convergence speed and parameter estimation error is demonstrated for several simulated data cases, and the results of actual flight data ana