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Sample records for fast tracking algorithm

  1. A Fast MEANSHIFT Algorithm-Based Target Tracking System

    PubMed Central

    Sun, Jian

    2012-01-01

    Tracking moving targets in complex scenes using an active video camera is a challenging task. Tracking accuracy and efficiency are two key yet generally incompatible aspects of a Target Tracking System (TTS). A compromise scheme will be studied in this paper. A fast mean-shift-based Target Tracking scheme is designed and realized, which is robust to partial occlusion and changes in object appearance. The physical simulation shows that the image signal processing speed is >50 frame/s. PMID:22969397

  2. Fast randomized Hough transformation track initiation algorithm based on multi-scale clustering

    NASA Astrophysics Data System (ADS)

    Wan, Minjie; Gu, Guohua; Chen, Qian; Qian, Weixian; Wang, Pengcheng

    2015-10-01

    A fast randomized Hough transformation track initiation algorithm based on multi-scale clustering is proposed to overcome existing problems in traditional infrared search and track system(IRST) which cannot provide movement information of the initial target and select the threshold value of correlation automatically by a two-dimensional track association algorithm based on bearing-only information . Movements of all the targets are presumed to be uniform rectilinear motion throughout this new algorithm. Concepts of space random sampling, parameter space dynamic linking table and convergent mapping of image to parameter space are developed on the basis of fast randomized Hough transformation. Considering the phenomenon of peak value clustering due to shortcomings of peak detection itself which is built on threshold value method, accuracy can only be ensured on condition that parameter space has an obvious peak value. A multi-scale idea is added to the above-mentioned algorithm. Firstly, a primary association is conducted to select several alternative tracks by a low-threshold .Then, alternative tracks are processed by multi-scale clustering methods , through which accurate numbers and parameters of tracks are figured out automatically by means of transforming scale parameters. The first three frames are processed by this algorithm in order to get the first three targets of the track , and then two slightly different gate radius are worked out , mean value of which is used to be the global threshold value of correlation. Moreover, a new model for curvilinear equation correction is applied to the above-mentioned track initiation algorithm for purpose of solving the problem of shape distortion when a space three-dimensional curve is mapped to a two-dimensional bearing-only space. Using sideways-flying, launch and landing as examples to build models and simulate, the application of the proposed approach in simulation proves its effectiveness , accuracy , and adaptivity

  3. Fast parallel tracking algorithm for the muon detector of the CBM experiment at fair

    NASA Astrophysics Data System (ADS)

    Lebedev, A.; Höhne, C.; Kisel, I.; Ososkov, G.

    2010-07-01

    Particle trajectory recognition is an important and challenging task in the Compressed Baryonic Matter (CBM) experiment at the future FAIR accelerator at Darmstadt. The tracking algorithms have to process terabytes of input data produced in particle collisions. Therefore, the speed of the tracking software is extremely important for data analysis. In this contribution, a fast parallel track reconstruction algorithm which uses available features of modern processors is presented. These features comprise a SIMD instruction set (SSE) and multithreading. The first allows one to pack several data items into one register and to operate on all of them in parallel thus achieving more operations per cycle. The second feature enables the routines to exploit all available CPU cores and hardware threads. This parallel version of the tracking algorithm has been compared to the initial serial scalar version which uses a similar approach for tracking. A speed-up factor of 487 was achieved (from 730 to 1.5 ms/event) for a computer with 2 × Intel Core i7 processors at 2.66 GHz.

  4. A segmentation algorithm for automated tracking of fast swimming unlabelled cells in three dimensions.

    PubMed

    Pimentel, J A; Carneiro, J; Darszon, A; Corkidi, G

    2012-01-01

    Recent advances in microscopy and cytolabelling methods enable the real time imaging of cells as they move and interact in their real physiological environment. Scenarios in which multiple cells move autonomously in all directions are not uncommon in biology. A remarkable example is the swimming of marine spermatozoa in search of the conspecific oocyte. Imaging cells in these scenarios, particularly when they move fast and are poorly labelled or even unlabelled requires very fast three-dimensional time-lapse (3D+t) imaging. This 3D+t imaging poses challenges not only to the acquisition systems but also to the image analysis algorithms. It is in this context that this work describes an original automated multiparticle segmentation method to analyse motile translucent cells in 3D microscopical volumes. The proposed segmentation technique takes advantage of the way the cell appearance changes with the distance to the focal plane position. The cells translucent properties and their interaction with light produce a specific pattern: when the cell is within or close to the focal plane, its two-dimensional (2D) appearance matches a bright spot surrounded by a dark ring, whereas when it is farther from the focal plane the cell contrast is inverted looking like a dark spot surrounded by a bright ring. The proposed method analyses the acquired video sequence frame-by-frame taking advantage of 2D image segmentation algorithms to identify and select candidate cellular sections. The crux of the method is in the sequential filtering of the candidate sections, first by template matching of the in-focus and out-of-focus templates and second by considering adjacent candidates sections in 3D. These sequential filters effectively narrow down the number of segmented candidate sections making the automatic tracking of cells in three dimensions a straightforward operation. PMID:21999166

  5. Development of a radiation-hardened SRAM with EDAC algorithm for fast readout CMOS pixel sensors for charged particle tracking

    NASA Astrophysics Data System (ADS)

    Wei, X.; Li, B.; Chen, N.; Wang, J.; Zheng, R.; Gao, W.; Wei, T.; Gao, D.; Hu, Y.

    2014-08-01

    CMOS pixel sensors (CPS) are attractive for use in the innermost particle detectors for charged particle tracking due to their good trade-off between spatial resolution, material budget, radiation hardness, and readout speed. With the requirements of high readout speed and high radiation hardness to total ionizing dose (TID) for particle tracking, fast readout CPS are composed by integrating a data compression block and two SRAM IP cores. However, the radiation hardness of the SRAM IP cores is not as high as that of the other parts in CPS, and thus the radiation hardness of the whole CPS chip is lowered. Especially, when CPS are migrated into 0.18-μm processes, the single event upset (SEU) effects should be also considered besides TID and single event latchup (SEL) effects. This paper presents a radiation-hardened SRAM with enhanced radiation hardness to SEU. An error detection and correction (EDAC) algorithm and a bit-interleaving storage strategy are adopted in the design. The prototype design has been fabricated in a 0.18-μm process. The area of the new SRAM is increased 1.6 times as compared with a non-radiation-hardened SRAM due to the integration of EDAC algorithm and the adoption of radiation hardened layout. The access time is increased from 5 ns to 8 ns due to the integration of EDAC algorithm. The test results indicate that the design satisfy requirements of CPS for charged particle tracking.

  6. Fast Compressive Tracking.

    PubMed

    Zhang, Kaihua; Zhang, Lei; Yang, Ming-Hsuan

    2014-10-01

    It is a challenging task to develop effective and efficient appearance models for robust object tracking due to factors such as pose variation, illumination change, occlusion, and motion blur. Existing online tracking algorithms often update models with samples from observations in recent frames. Despite much success has been demonstrated, numerous issues remain to be addressed. First, while these adaptive appearance models are data-dependent, there does not exist sufficient amount of data for online algorithms to learn at the outset. Second, online tracking algorithms often encounter the drift problems. As a result of self-taught learning, misaligned samples are likely to be added and degrade the appearance models. In this paper, we propose a simple yet effective and efficient tracking algorithm with an appearance model based on features extracted from a multiscale image feature space with data-independent basis. The proposed appearance model employs non-adaptive random projections that preserve the structure of the image feature space of objects. A very sparse measurement matrix is constructed to efficiently extract the features for the appearance model. We compress sample images of the foreground target and the background using the same sparse measurement matrix. The tracking task is formulated as a binary classification via a naive Bayes classifier with online update in the compressed domain. A coarse-to-fine search strategy is adopted to further reduce the computational complexity in the detection procedure. The proposed compressive tracking algorithm runs in real-time and performs favorably against state-of-the-art methods on challenging sequences in terms of efficiency, accuracy and robustness. PMID:26352631

  7. Large scale tracking algorithms.

    SciTech Connect

    Hansen, Ross L.; Love, Joshua Alan; Melgaard, David Kennett; Karelitz, David B.; Pitts, Todd Alan; Zollweg, Joshua David; Anderson, Dylan Z.; Nandy, Prabal; Whitlow, Gary L.; Bender, Daniel A.; Byrne, Raymond Harry

    2015-01-01

    Low signal-to-noise data processing algorithms for improved detection, tracking, discrimination and situational threat assessment are a key research challenge. As sensor technologies progress, the number of pixels will increase signi cantly. This will result in increased resolution, which could improve object discrimination, but unfortunately, will also result in a significant increase in the number of potential targets to track. Many tracking techniques, like multi-hypothesis trackers, suffer from a combinatorial explosion as the number of potential targets increase. As the resolution increases, the phenomenology applied towards detection algorithms also changes. For low resolution sensors, "blob" tracking is the norm. For higher resolution data, additional information may be employed in the detection and classfication steps. The most challenging scenarios are those where the targets cannot be fully resolved, yet must be tracked and distinguished for neighboring closely spaced objects. Tracking vehicles in an urban environment is an example of such a challenging scenario. This report evaluates several potential tracking algorithms for large-scale tracking in an urban environment.

  8. Fast tracking hospital construction.

    PubMed

    Quirk, Andrew

    2013-03-01

    Hospital leaders should consider four factors in determining whether to fast track a hospital construction project: Expectations of project length, quality, and cost. Whether decisions can be made quickly as issues arise. Their own time commitment to the project, as well as that of architects, engineers, construction managers, and others. The extent to which they are willing to share with the design and construction teams how and why decisions are being made. PMID:23513759

  9. Fast Track Study

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The NASA Fast Track Study supports the efforts of a Special Study Group (SSG) made up of members of the Advanced Project Management Class number 23 (APM-23) that met at the Wallops Island Management Education Center from April 28 - May 8, 1996. Members of the Class expressed interest to Mr. Vem Weyers in having an input to the NASA Policy Document (NPD) 7120.4, that will replace NASA Management Institute (NMI) 7120.4, and the NASA Program/Project Management Guide. The APM-23 SSG was tasked with assisting in development of NASA policy on managing Fast Track Projects, defined as small projects under $150 million and completed within three years. 'Me approach of the APM-23 SSG was to gather data on successful projects working in a 'Better, Faster, Cheaper' environment, within and outside of NASA and develop the Fast Track Project section of the NASA Program/Project Management Guide. Fourteen interviews and four other data gathering efforts were conducted by the SSG, and 16 were conducted by Strategic Resources, Inc. (SRI), including five interviews at the Jet Propulsion Laboratory (JPL) and one at the Applied Physics Laboratory (APL). The interviews were compiled and analyzed for techniques and approaches commonly used to meet severe cost and schedule constraints.

  10. A fast meteor detection algorithm

    NASA Astrophysics Data System (ADS)

    Gural, P.

    2016-01-01

    A low latency meteor detection algorithm for use with fast steering mirrors had been previously developed to track and telescopically follow meteors in real-time (Gural, 2007). It has been rewritten as a generic clustering and tracking software module for meteor detection that meets both the demanding throughput requirements of a Raspberry Pi while also maintaining a high probability of detection. The software interface is generalized to work with various forms of front-end video pre-processing approaches and provides a rich product set of parameterized line detection metrics. Discussion will include the Maximum Temporal Pixel (MTP) compression technique as a fast thresholding option for feeding the detection module, the detection algorithm trade for maximum processing throughput, details on the clustering and tracking methodology, processing products, performance metrics, and a general interface description.

  11. NEKF IMM tracking algorithm

    NASA Astrophysics Data System (ADS)

    Owen, Mark W.; Stubberud, Allen R.

    2003-12-01

    Highly maneuvering threats are a major concern for the Navy and the DoD and the technology discussed in this paper is intended to help address this issue. A neural extended Kalman filter algorithm has been embedded in an interacting multiple model architecture for target tracking. The neural extended Kalman filter algorithm is used to improve motion model prediction during maneuvers. With a better target motion mode, noise reduction can be achieved through a maneuver. Unlike the interacting multiple model architecture which uses a high process noise model to hold a target through a maneuver with poor velocity and acceleration estimates, a neural extended Kalman filter is used to predict corrections to the velocity and acceleration states of a target through a maneuver. The neural extended Kalman filter estimates the weights of a neural network, which in turn are used to modify the state estimate predictions of the filter as measurements are processed. The neural network training is performed on-line as data is processed. In this paper, the simulation results of a tracking problem using a neural extended Kalman filter embedded in an interacting multiple model tracking architecture are shown. Preliminary results on the 2nd Benchmark Problem are also given.

  12. NEKF IMM tracking algorithm

    NASA Astrophysics Data System (ADS)

    Owen, Mark W.; Stubberud, Allen R.

    2004-01-01

    Highly maneuvering threats are a major concern for the Navy and the DoD and the technology discussed in this paper is intended to help address this issue. A neural extended Kalman filter algorithm has been embedded in an interacting multiple model architecture for target tracking. The neural extended Kalman filter algorithm is used to improve motion model prediction during maneuvers. With a better target motion mode, noise reduction can be achieved through a maneuver. Unlike the interacting multiple model architecture which uses a high process noise model to hold a target through a maneuver with poor velocity and acceleration estimates, a neural extended Kalman filter is used to predict corrections to the velocity and acceleration states of a target through a maneuver. The neural extended Kalman filter estimates the weights of a neural network, which in turn are used to modify the state estimate predictions of the filter as measurements are processed. The neural network training is performed on-line as data is processed. In this paper, the simulation results of a tracking problem using a neural extended Kalman filter embedded in an interacting multiple model tracking architecture are shown. Preliminary results on the 2nd Benchmark Problem are also given.

  13. TrackEye tracking algorithm characterization

    NASA Astrophysics Data System (ADS)

    Valley, Michael T.; Shields, Robert W.; Reed, Jack M.

    2004-10-01

    TrackEye is a film digitization and target tracking system that offers the potential for quantitatively measuring the dynamic state variables (e.g., absolute and relative position, orientation, linear and angular velocity/acceleration, spin rate, trajectory, angle of attack, etc.) for moving objects using captured single or dual view image sequences. At the heart of the system is a set of tracking algorithms that automatically find and quantify the location of user selected image details such as natural test article features or passive fiducials that have been applied to cooperative test articles. This image position data is converted into real world coordinates and rates with user specified information such as the image scale and frame rate. Though tracking methods such as correlation algorithms are typically robust by nature, the accuracy and suitability of each TrackEye tracking algorithm is in general unknown even under good imaging conditions. The challenges of optimal algorithm selection and algorithm performance/measurement uncertainty are even more significant for long range tracking of high-speed targets where temporally varying atmospheric effects degrade the imagery. This paper will present the preliminary results from a controlled test sequence used to characterize the performance of the TrackEye tracking algorithm suite.

  14. TrackEye tracking algorithm characterization.

    SciTech Connect

    Reed, Jack W.; Shields, Rob W; Valley, Michael T.

    2004-08-01

    TrackEye is a film digitization and target tracking system that offers the potential for quantitatively measuring the dynamic state variables (e.g., absolute and relative position, orientation, linear and angular velocity/acceleration, spin rate, trajectory, angle of attack, etc.) for moving objects using captured single or dual view image sequences. At the heart of the system is a set of tracking algorithms that automatically find and quantify the location of user selected image details such as natural test article features or passive fiducials that have been applied to cooperative test articles. This image position data is converted into real world coordinates and rates with user specified information such as the image scale and frame rate. Though tracking methods such as correlation algorithms are typically robust by nature, the accuracy and suitability of each TrackEye tracking algorithm is in general unknown even under good imaging conditions. The challenges of optimal algorithm selection and algorithm performance/measurement uncertainty are even more significant for long range tracking of high-speed targets where temporally varying atmospheric effects degrade the imagery. This paper will present the preliminary results from a controlled test sequence used to characterize the performance of the TrackEye tracking algorithm suite.

  15. Tracking filter algorithm for automatic video tracking

    NASA Astrophysics Data System (ADS)

    McEver, Mark A.; Kimbrell, James E.

    2006-05-01

    In addition to servo control and power amplification, motion control systems for optical tracking pedestals feature capabilities such as electro-optical tracking using an integrated Automatic Video Tracker (AVT) card. An electro-optical system tracking loop is comprised of sensors mounted on a pointing pedestal, an AVT that detects a target in the sensor imagery, and a tracking filter algorithm that commands the pedestal to follow the target. The tracking filter algorithm receives the target boresight error from the AVT and calculates motion demands for the pedestal servo controller. This paper presents a tracking algorithm based on target state estimation using a Kalman filter. The servo demands are based on calculating the Kalman filter state estimate from absolute line-of-sight angles to the target. Simulations are used to compare its performance to tracking loops without tracking filters, and to other tracking filter algorithms, such as rate feedback loops closed around boresight error. Issues such as data latency and sensor alignment error are discussed.

  16. Fast-Tracking Colostomy Closures.

    PubMed

    Nanavati, Aditya J; Prabhakar, Subramaniam

    2015-12-01

    There have been very few studies on applying fast-track principles to colostomy closures. We believe that outcome may be significantly improved with multimodal interventions in the peri-operative care of patients undergoing this procedure. A retrospective study was carried out comparing patients who had undergone colostomy closures by the fast-track and traditional care protocols at our centre. We intended to analyse peri-operative period and recovery in colostomy closures to confirm that fast-track surgery principles improved outcomes. Twenty-six patients in the fast-track arm and 24 patients in the traditional care arm had undergone colostomy closures. Both groups were comparable in terms of their baseline parameters. Patients in the fast-track group were ambulatory and accepted oral feeding earlier. There was a significant reduction in the duration of stay (4.73 ± 1.43 days vs. 7.21 ± 1.38 days, p = 0.0000). We did not observe a rise in complications or 30-day re-admissions. Fast-track surgery can safely be applied to colostomy closures. It shows earlier ambulation and reduction in length of hospital stay. PMID:27011527

  17. Fast SIMDized Kalman filter based track fit

    NASA Astrophysics Data System (ADS)

    Gorbunov, S.; Kebschull, U.; Kisel, I.; Lindenstruth, V.; Müller, W. F. J.

    2008-03-01

    Modern high energy physics experiments have to process terabytes of input data produced in particle collisions. The core of many data reconstruction algorithms in high energy physics is the Kalman filter. Therefore, the speed of Kalman filter based algorithms is of crucial importance in on-line data processing. This is especially true for the combinatorial track finding stage where the Kalman filter based track fit is used very intensively. Therefore, developing fast reconstruction algorithms, which use maximum available power of processors, is important, in particular for the initial selection of events which carry signals of interesting physics. One of such powerful feature supported by almost all up-to-date PC processors is a SIMD instruction set, which allows packing several data items in one register and to operate on all of them, thus achieving more operations per clock cycle. The novel Cell processor extends the parallelization further by combining a general-purpose PowerPC processor core with eight streamlined coprocessing elements which greatly accelerate vector processing applications. In the investigation described here, after a significant memory optimization and a comprehensive numerical analysis, the Kalman filter based track fitting algorithm of the CBM experiment has been vectorized using inline operator overloading. Thus the algorithm continues to be flexible with respect to any CPU family used for data reconstruction. Because of all these changes the SIMDized Kalman filter based track fitting algorithm takes 1 μs per track that is 10000 times faster than the initial version. Porting the algorithm to a Cell Blade computer gives another factor of 10 of the speedup. Finally, we compare performance of the tracking algorithm running on three different CPU architectures: Intel Xeon, AMD Opteron and Cell Broadband Engine.

  18. Fast-Track Teacher Recruitment.

    ERIC Educational Resources Information Center

    Grant, Franklin Dean

    2001-01-01

    Schools need a Renaissance human-resources director to implement strategic staffing and fast-track teacher-recruitment plans. The HR director must attend to customer satisfaction, candidate supply, web-based recruitment possibilities, stabilization of newly hired staff, retention of veteran staff, utilization of retired employees, and latest…

  19. Fast tracking using edge histograms

    NASA Astrophysics Data System (ADS)

    Rokita, Przemyslaw

    1997-04-01

    This paper proposes a new algorithm for tracking objects and objects boundaries. This algorithm was developed and applied in a system used for compositing computer generated images and real world video sequences, but can be applied in general in all tracking systems where accuracy and high processing speed are required. The algorithm is based on analysis of histograms obtained by summing along chosen axles pixels of edge segmented images. Edge segmentation is done by spatial convolution using gradient operator. The advantage of such an approach is that it can be performed in real-time using available on the market hardware convolution filters. After edge extraction and histograms computation, respective positions of maximums in edge intensity histograms, in current and previous frame, are compared and matched. Obtained this way information about displacement of histograms maximums, can be directly converted into information about changes of target boundaries positions along chosen axles.

  20. Fast track to 340B.

    PubMed

    Gricius, Robert F; Wong, Douglas

    2016-01-01

    Hospitals that are newly qualified for the 340B Drug Pricing Program may have an opportunity for fast-track approval to participate in the program. Three steps are required to seize this opportunity: Use data analytics to assess current and future percentages of Medicaid utilization and eligibility for federal SSI cash benefits. Determine the feasibility of early cost report filing. Prepare appropriate documentation and undertake the initial enrollment process. PMID:26863836

  1. PUBLISHER'S ANNOUNCEMENT: Fast Track Communications

    NASA Astrophysics Data System (ADS)

    Wald, Robert; Adams, Judith

    2006-12-01

    We are very pleased to announce that Classical and Quantum Gravity will launch a new Fast Track Communications section from January 2007, after which date Letters to the Editor will no longer be published. Fast Track Communications (FTCs) are short, timely papers presenting only the most important new developments. To reflect their high significance FTCs will be published at the front of the journal and will be freely available online to ensure the widest visibility. As with all articles submitted to Classical and Quantum Gravity, there are no page charges, including online colour reproduction and multi-media attachments. Authors who wish to include colour in the print version of their article will, however, be required to cover the costs. Submissions to the new Fast Track Communications section are very welcome. For details of how to submit an FTC please visit IOP Publishing's webpages http://authors.iop.org, or contact the journal at cqg@iop.org. To facilitate refereeing, authors are asked to submit a short statement accompanying their FTC, outlining why they feel that the article merits high-priority publication. Length restrictions will also be applied such that FTCs should be a maximum of 8 journal pages (5000 words) in length. The section will aim to be a high-quality, high-profile outlet for new and important research of interest to the Classical and Quantum Gravity community. We look forward to seeing it grow and take shape over the next year.

  2. Knowledge-based tracking algorithm

    NASA Astrophysics Data System (ADS)

    Corbeil, Allan F.; Hawkins, Linda J.; Gilgallon, Paul F.

    1990-10-01

    This paper describes the Knowledge-Based Tracking (KBT) algorithm for which a real-time flight test demonstration was recently conducted at Rome Air Development Center (RADC). In KBT processing, the radar signal in each resolution cell is thresholded at a lower than normal setting to detect low RCS targets. This lower threshold produces a larger than normal false alarm rate. Therefore, additional signal processing including spectral filtering, CFAR and knowledge-based acceptance testing are performed to eliminate some of the false alarms. TSC's knowledge-based Track-Before-Detect (TBD) algorithm is then applied to the data from each azimuth sector to detect target tracks. In this algorithm, tentative track templates are formed for each threshold crossing and knowledge-based association rules are applied to the range, Doppler, and azimuth measurements from successive scans. Lastly, an M-association out of N-scan rule is used to declare a detection. This scan-to-scan integration enhances the probability of target detection while maintaining an acceptably low output false alarm rate. For a real-time demonstration of the KBT algorithm, the L-band radar in the Surveillance Laboratory (SL) at RADC was used to illuminate a small Cessna 310 test aircraft. The received radar signal wa digitized and processed by a ST-100 Array Processor and VAX computer network in the lab. The ST-100 performed all of the radar signal processing functions, including Moving Target Indicator (MTI) pulse cancelling, FFT Doppler filtering, and CFAR detection. The VAX computers performed the remaining range-Doppler clustering, beamsplitting and TBD processing functions. The KBT algorithm provided a 9.5 dB improvement relative to single scan performance with a nominal real time delay of less than one second between illumination and display.

  3. Fast track management and control

    SciTech Connect

    Cameron, M.D.O.

    1996-12-31

    This paper, one of a group of papers describing the development of BP`s West of Shetland Foinaven field will set-out the challenges experienced in managing a fast-track project from system design through to offshore installation. ABB Seatec Limited (formerly GEC Marconi Oil and Gas) were commissioned to provide a Multiplexed Electro-Hydraulic Subsea Control System designed for deepwater and for installation/retrieval in a hostile environment. The paper will address the projects critical phase, the project controls implemented, the practical working methods used within a Subsea Alliance and those involved in Client Interaction, Concurrent Engineering, Team Coaching, Internal Procedures and Interface Management in order to meet the exacting schedule for First Oil deliveries. The Project is currently proceeding on routine production deliveries to complete the field development requirements.

  4. A Probabilistic Cell Tracking Algorithm

    NASA Astrophysics Data System (ADS)

    Steinacker, Reinhold; Mayer, Dieter; Leiding, Tina; Lexer, Annemarie; Umdasch, Sarah

    2013-04-01

    The research described below was carried out during the EU-Project Lolight - development of a low cost, novel and accurate lightning mapping and thunderstorm (supercell) tracking system. The Project aims to develop a small-scale tracking method to determine and nowcast characteristic trajectories and velocities of convective cells and cell complexes. The results of the algorithm will provide a higher accuracy than current locating systems distributed on a coarse scale. Input data for the developed algorithm are two temporally separated lightning density fields. Additionally a Monte Carlo method minimizing a cost function is utilizied which leads to a probabilistic forecast for the movement of thunderstorm cells. In the first step the correlation coefficients between the first and the second density field are computed. Hence, the first field is shifted by all shifting vectors which are physically allowed. The maximum length of each vector is determined by the maximum possible speed of thunderstorm cells and the difference in time for both density fields. To eliminate ambiguities in determination of directions and velocities, the so called Random Walker of the Monte Carlo process is used. Using this method a grid point is selected at random. Moreover, one vector out of all predefined shifting vectors is suggested - also at random but with a probability that is related to the correlation coefficient. If this exchange of shifting vectors reduces the cost function, the new direction and velocity are accepted. Otherwise it is discarded. This process is repeated until the change of cost functions falls below a defined threshold. The Monte Carlo run gives information about the percentage of accepted shifting vectors for all grid points. In the course of the forecast, amplifications of cell density are permitted. For this purpose, intensity changes between the investigated areas of both density fields are taken into account. Knowing the direction and speed of thunderstorm

  5. Improved motion information-based infrared dim target tracking algorithms

    NASA Astrophysics Data System (ADS)

    Lei, Liu; Zhijian, Huang

    2014-11-01

    Accurate and fast tracking of infrared (IR) dim target has very important meaning for infrared precise guidance, early warning, video surveillance, etc. However, under complex backgrounds, such as clutter, varying illumination, and occlusion, the traditional tracking method often converges to a local maximum and loses the real infrared target. To cope with these problems, three improved tracking algorithm based on motion information are proposed in this paper, namely improved mean shift algorithm, improved Optical flow method and improved Particle Filter method. The basic principles and the implementing procedure of these modified algorithms for target tracking are described. Using these algorithms, the experiments on some real-life IR and color images are performed. The whole algorithm implementing processes and results are analyzed, and those algorithms for tracking targets are evaluated from the two aspects of subjective and objective. The results prove that the proposed method has satisfying tracking effectiveness and robustness. Meanwhile, it has high tracking efficiency and can be used for real-time tracking.

  6. [FAST TRACK CONCEPT IN MODERN NEUROANESTHESIOLOGY].

    PubMed

    Kulikov, A S; Lubnin, A Yu

    2016-01-01

    The concept of fast-track is one of the most discussed trends in the development of modern surgery. According to supporters of this ideology, the use of fast-track leads to the reduction ofhospital stay without increasing in readmission, reducing the frequency of postoperative complications, which is reflected in the decrease in the cost of the treatment and social expenses, due to earlier return of patients to normal life. The authors of this review discuss different anesthetic issues of fast-track approach (early awakening, postoperative analgesia, prevention of PONV; neuromuscular block reversion). The paper contains also valuable reasons for using fast-track in neurosurgery, as well as contraindications to the use of this approach. PMID:27468505

  7. The Physics of Fast Track

    ERIC Educational Resources Information Center

    Kibble, Bob

    2007-01-01

    Toys can provide motivational contexts for learning and teaching about physics. A cheap car track provides an almost frictionless environment from which a quantitative study of conservation of energy and circular motion can be made.

  8. Math on the Fast Track

    ERIC Educational Resources Information Center

    Howe, Quincy

    2006-01-01

    In this article, the author relates how a math-assessment software has allowed his school to track the academic progress of its students. The author relates that in the first year that the software was deployed, schoolwide averages in terms of national standing on the math ITBS rose from the 42nd to 59th percentile. In addition, a significant…

  9. Fast-track surgery in India.

    PubMed

    Nanavati, Aditya J; Nagral, Sanjay; Prabhakar, Subramaniam

    2014-01-01

    Fast-track surgery or 'enhanced recovery after surgery' or 'multimodal rehabilitation after surgery' is a form of protocol-based perioperative care programme. It is an amalgamation of evidence-based practices that have been proven to improve patient outcome independently and exert a synergistic effect when applied together. The philosophy is to treat the patient's pathology with minimal disturbance to the physiology. Several surgical subspecialties have now adopted such protocols with good results. The role of fast-track surgery in colorectal procedures has been well demonstrated. Its application to other major abdominal surgical procedures is not as well defined but there are encouraging results in the few studies conducted. There has been resistance to several aspects of this programme among gastrointestinal and general surgeons. There is little data from India in the available literature on the application of fast-tracking in gastrointestinal surgery. In a country such as India the existing healthcare structure stands to gain the most by widespread adoption of fast-track methods. Early discharge, early ambulation, earlier return to work and increased hospital efficiency are some of the benefits. The cost gains derived from this programme stand to benefit the patient, doctor and government as well. The practice and implementation of fast-track surgery involves a multidisciplinary team approach. It requires policy formation at an institutional level and interdepartmental coordination. More research is required in areas like implementation of such protocols across India to derive the maximum benefit from them. PMID:25471759

  10. A Reliability-Based Track Fusion Algorithm

    PubMed Central

    Xu, Li; Pan, Liqiang; Jin, Shuilin; Liu, Haibo; Yin, Guisheng

    2015-01-01

    The common track fusion algorithms in multi-sensor systems have some defects, such as serious imbalances between accuracy and computational cost, the same treatment of all the sensor information regardless of their quality, high fusion errors at inflection points. To address these defects, a track fusion algorithm based on the reliability (TFR) is presented in multi-sensor and multi-target environments. To improve the information quality, outliers in the local tracks are eliminated at first. Then the reliability of local tracks is calculated, and the local tracks with high reliability are chosen for the state estimation fusion. In contrast to the existing methods, TFR reduces high fusion errors at the inflection points of system tracks, and obtains a high accuracy with less computational cost. Simulation results verify the effectiveness and the superiority of the algorithm in dense sensor environments. PMID:25950174

  11. Fast-tracking in cardiac surgery.

    PubMed

    Aps, C

    Fast-tracking in cardiac surgery evolved as the pressure on bed space in intensive therapy units (ITU) grew and clinical management improved. It relies on achieving a patient condition that allows for earlier extubation and postoperative management in alternative facilities to the ITU. PMID:7582363

  12. Accelerated Leadership Development: Fast Tracking School Leaders

    ERIC Educational Resources Information Center

    Earley, Peter; Jones, Jeff

    2010-01-01

    "Accelerated Leadership Development" captures and communicates the lessons learned from successful fast-track leadership programmes in the private and public sector, and provides a model which schools can follow and customize as they plan their own leadership development strategies. As large numbers of headteachers and other senior staff retire,…

  13. UWB Tracking Algorithms: AOA and TDOA

    NASA Technical Reports Server (NTRS)

    Ni, Jianjun David; Arndt, D.; Ngo, P.; Gross, J.; Refford, Melinda

    2006-01-01

    Ultra-Wideband (UWB) tracking prototype systems are currently under development at NASA Johnson Space Center for various applications on space exploration. For long range applications, a two-cluster Angle of Arrival (AOA) tracking method is employed for implementation of the tracking system; for close-in applications, a Time Difference of Arrival (TDOA) positioning methodology is exploited. Both AOA and TDOA are chosen to utilize the achievable fine time resolution of UWB signals. This talk presents a brief introduction to AOA and TDOA methodologies. The theoretical analysis of these two algorithms reveal the affecting parameters impact on the tracking resolution. For the AOA algorithm, simulations show that a tracking resolution less than 0.5% of the range can be achieved with the current achievable time resolution of UWB signals. For the TDOA algorithm used in close-in applications, simulations show that the (sub-inch) high tracking resolution is achieved with a chosen tracking baseline configuration. The analytical and simulated results provide insightful guidance for the UWB tracking system design.

  14. Fast infrared dim and small target tracking

    NASA Astrophysics Data System (ADS)

    Qian, Kun; Zhou, Huixin; Rong, Shenghui; Wang, Bingjian; Yin, Shiming; Zeng, Qingjie

    2015-10-01

    The target tracking by the spatio-temporal learning is a kind of online tracking algorithm based on Bayesian framework. But it has the excursion problem when applied in the infrared dim target. Based on the principle of the spatio-temporal learning algorithm, the excursion problem was analyzed and a new robust algorithm for infrared dim target tracking is proposed in this paper. Firstly, the Guide Image Filter was adopted to process the input image to preserve edges and eliminate the noise of the image. Secondly, the ideal spatial context model was calculated with the input image that contains little noise, which can be got by subtracting the filtering result from the original image. Simultaneously, a new weight in the context prior model was proposed to indicate that the prior is also related to the local gray level difference. The performance of the presented algorithm was tested with two infrared air image sequences, and the experimental results show that the proposed algorithm performs well in terms of efficiency, accuracy and robustness.

  15. Fast decoding algorithms for coded aperture systems

    NASA Astrophysics Data System (ADS)

    Byard, Kevin

    2014-08-01

    Fast decoding algorithms are described for a number of established coded aperture systems. The fast decoding algorithms for all these systems offer significant reductions in the number of calculations required when reconstructing images formed by a coded aperture system and hence require less computation time to produce the images. The algorithms may therefore be of use in applications that require fast image reconstruction, such as near real-time nuclear medicine and location of hazardous radioactive spillage. Experimental tests confirm the efficacy of the fast decoding techniques.

  16. Procrustes algorithm for multisensor track fusion

    NASA Astrophysics Data System (ADS)

    Fernandez, Manuel F.; Aridgides, Tom; Evans, John S., Jr.

    1990-10-01

    The association or "fusion" of multiple-sensor reports allows the generation of a highly accurate description of the environment by enabling efficient compression and processing of otherwise unwieldy quantities of data. Assuming that the observations from each sensor are aligned in feature space and in time, this association procedure may be executed on the basis of how well each sensor's vectors of observations match previously fused tracks. Unfortunately, distance-based algorithms alone do not suffice in those situations where match-assignments are not of an obvious nature (e.g., high target density or high false alarm rate scenarios). Our proposed approach is based on recognizing that, together, the sensors' observations and the fused tracks span a vector subspace whose dimensionality and singularity characteristics can be used to determine the total number of targets appearing across sensors. A properly constrained transformation can then be found which aligns the subspaces spanned individually by the observations and by the fused tracks, yielding the relationship existing between both sets of vectors ("Procrustes Problem"). The global nature of this approach thus enables fusing closely-spaced targets by treating them--in a manner analogous to PDA/JPDA algorithms - as clusters across sensors. Since our particular version of the Procrustes Problem consists basically of a minimization in the Total Least Squares sense, the resulting transformations associate both observations-to-tracks and tracks-to--observations. This means that the number of tracks being updated will increase or decrease depending on the number of targets present, automatically initiating or deleting "fused" tracks as required, without the need of ancillary procedures. In addition, it is implicitly assumed that both the tracker filters' target trajectory models and the sensors' observations are "noisy", yielding an algorithm robust even against maneuvering targets. Finally, owing to the fact

  17. Fast object tracking based on template matching and region information fusion extraction

    NASA Astrophysics Data System (ADS)

    Liu, Liman; Chen, Yun; Liu, Haihua

    2015-12-01

    In this paper, a fast object tracking algorithm based on template matching and region information fusion extraction is proposed. In the prediction framework, the data connection task is achieved by object template and object information extraction. And then the object is tracked accurately by using the object motion information. We handle the tracking shift by using the confidence estimation strategy. The experiments show that the proposed algorithm has robust performance.

  18. Online empirical evaluation of tracking algorithms.

    PubMed

    Wu, Hao; Sankaranarayanan, Aswin C; Chellappa, Rama

    2010-08-01

    Evaluation of tracking algorithms in the absence of ground truth is a challenging problem. There exist a variety of approaches for this problem, ranging from formal model validation techniques to heuristics that look for mismatches between track properties and the observed data. However, few of these methods scale up to the task of visual tracking, where the models are usually nonlinear and complex and typically lie in a high-dimensional space. Further, scenarios that cause track failures and/or poor tracking performance are also quite diverse for the visual tracking problem. In this paper, we propose an online performance evaluation strategy for tracking systems based on particle filters using a time-reversed Markov chain. The key intuition of our proposed methodology relies on the time-reversible nature of physical motion exhibited by most objects, which in turn should be possessed by a good tracker. In the presence of tracking failures due to occlusion, low SNR, or modeling errors, this reversible nature of the tracker is violated. We use this property for detection of track failures. To evaluate the performance of the tracker at time instant t, we use the posterior of the tracking algorithm to initialize a time-reversed Markov chain. We compute the posterior density of track parameters at the starting time t=0 by filtering back in time to the initial time instant. The distance between the posterior density of the time-reversed chain (at t=0) and the prior density used to initialize the tracking algorithm forms the decision statistic for evaluation. It is observed that when the data are generated by the underlying models, the decision statistic takes a low value. We provide a thorough experimental analysis of the evaluation methodology. Specifically, we demonstrate the effectiveness of our approach for tackling common challenges such as occlusion, pose, and illumination changes and provide the Receiver Operating Characteristic (ROC) curves. Finally, we also show

  19. 40 CFR 72.82 - Fast-track modifications.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 false Fast-track modifications. 72.82... (CONTINUED) PERMITS REGULATION Permit Revisions § 72.82 Fast-track modifications. The following procedures shall apply to all fast-track modifications. (a) If the Administrator is the permitting authority,...

  20. 40 CFR 72.82 - Fast-track modifications.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 17 2012-07-01 2012-07-01 false Fast-track modifications. 72.82... (CONTINUED) PERMITS REGULATION Permit Revisions § 72.82 Fast-track modifications. The following procedures shall apply to all fast-track modifications. (a) If the Administrator is the permitting authority,...

  1. 40 CFR 72.82 - Fast-track modifications.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 false Fast-track modifications. 72.82... (CONTINUED) PERMITS REGULATION Permit Revisions § 72.82 Fast-track modifications. The following procedures shall apply to all fast-track modifications. (a) If the Administrator is the permitting authority,...

  2. 40 CFR 72.82 - Fast-track modifications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Fast-track modifications. 72.82... (CONTINUED) PERMITS REGULATION Permit Revisions § 72.82 Fast-track modifications. The following procedures shall apply to all fast-track modifications. (a) If the Administrator is the permitting authority,...

  3. 40 CFR 72.82 - Fast-track modifications.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Fast-track modifications. 72.82... (CONTINUED) PERMITS REGULATION Permit Revisions § 72.82 Fast-track modifications. The following procedures shall apply to all fast-track modifications. (a) If the Administrator is the permitting authority,...

  4. UWB Tracking System Design with TDOA Algorithm

    NASA Technical Reports Server (NTRS)

    Ni, Jianjun; Arndt, Dickey; Ngo, Phong; Phan, Chau; Gross, Julia; Dusl, John; Schwing, Alan

    2006-01-01

    This presentation discusses an ultra-wideband (UWB) tracking system design effort using a tracking algorithm TDOA (Time Difference of Arrival). UWB technology is exploited to implement the tracking system due to its properties, such as high data rate, fine time resolution, and low power spectral density. A system design using commercially available UWB products is proposed. A two-stage weighted least square method is chosen to solve the TDOA non-linear equations. Matlab simulations in both two-dimensional space and three-dimensional space show that the tracking algorithm can achieve fine tracking resolution with low noise TDOA data. The error analysis reveals various ways to improve the tracking resolution. Lab experiments demonstrate the UWBTDOA tracking capability with fine resolution. This research effort is motivated by a prototype development project Mini-AERCam (Autonomous Extra-vehicular Robotic Camera), a free-flying video camera system under development at NASA Johnson Space Center for aid in surveillance around the International Space Station (ISS).

  5. Neural network fusion capabilities for efficient implementation of tracking algorithms

    NASA Astrophysics Data System (ADS)

    Sundareshan, Malur K.; Amoozegar, Farid

    1996-05-01

    The ability to efficiently fuse information of different forms for facilitating intelligent decision-making is one of the major capabilities of trained multilayer neural networks that is being recognized int eh recent times. While development of innovative adaptive control algorithms for nonlinear dynamical plants which attempt to exploit these capabilities seems to be more popular, a corresponding development of nonlinear estimation algorithms using these approaches, particularly for application in target surveillance and guidance operations, has not received similar attention. In this paper we describe the capabilities and functionality of neural network algorithms for data fusion and implementation of nonlinear tracking filters. For a discussion of details and for serving as a vehicle for quantitative performance evaluations, the illustrative case of estimating the position and velocity of surveillance targets is considered. Efficient target tracking algorithms that can utilize data from a host of sensing modalities and are capable of reliably tracking even uncooperative targets executing fast and complex maneuvers are of interest in a number of applications. The primary motivation for employing neural networks in these applications comes form the efficiency with which more features extracted from different sensor measurements can be utilized as inputs for estimating target maneuvers. Such an approach results in an overall nonlinear tracking filter which has several advantages over the popular efforts at designing nonlinear estimation algorithms for tracking applications, the principle one being the reduction of mathematical and computational complexities. A system architecture that efficiently integrates the processing capabilities of a trained multilayer neural net with the tracking performance of a Kalman filter is described in this paper.

  6. HYBRID FAST HANKEL TRANSFORM ALGORITHM FOR ELECTROMAGNETIC MODELING

    EPA Science Inventory

    A hybrid fast Hankel transform algorithm has been developed that uses several complementary features of two existing algorithms: Anderson's digital filtering or fast Hankel transform (FHT) algorithm and Chave's quadrature and continued fraction algorithm. A hybrid FHT subprogram ...

  7. 1995 Fast Track: cost reduction and improvement.

    PubMed

    Panzer, R J; Tuttle, D N; Kolker, R M

    1997-01-01

    To respond to a cost reduction crisis, Strong Memorial Hospital implemented an aggressively managed program of accelerated improvement teams. "Fast-track" teams combined the application of many management tools (total quality management, breakthrough thinking, reengineering, etc.) into one problem-solving process. Teams and managers were charged to work on specific cost reduction strategies. Teams were given additional instruction on interpersonal skills such as communication, teamwork, and leadership. Paradoxically, quality improvement in our hospital was advanced more through this effort at cost reduction than had previously been done in the name of quality itself. PMID:10176411

  8. Fast algorithms for transport models

    SciTech Connect

    Manteuffel, T.A.

    1992-12-01

    The objective of this project is the development of numerical solution techniques for deterministic models of the transport of neutral and charged particles and the demonstration of their effectiveness in both a production environment and on advanced architecture computers. The primary focus is on various versions of the linear Boltzman equation. These equations are fundamental in many important applications. This project is an attempt to integrate the development of numerical algorithms with the process of developing production software. A major thrust of this reject will be the implementation of these algorithms on advanced architecture machines that reside at the Advanced Computing Laboratory (ACL) at Los Alamos National Laboratories (LANL).

  9. A fast assistant decision-making system on the emergent maneuver of the tracking ship

    NASA Astrophysics Data System (ADS)

    Huang, Qiong; Xue, G. H.; Ni, X. Q.

    2016-02-01

    This paper studies a fast assistant decision-making system on the emergent maneuver of the tracking ship, adopting the design method of the emergent working state of the tracking ship based on the meteorological prediction, the virtual display technology based on the multi-stage mapping, and the 2-dimension area algorithm based on the line-scanning. It solves problems that the tracking ship met during working, such as the long TT&C time, the dense crucial observation arc, the complicated working flow, and the changeful scheme. It established the hard basement for the fast design of the emergency working state when the tracking ship in the awful sea conditions.

  10. Fast ordering algorithm for exact histogram specification.

    PubMed

    Nikolova, Mila; Steidl, Gabriele

    2014-12-01

    This paper provides a fast algorithm to order in a meaningful, strict way the integer gray values in digital (quantized) images. It can be used in any exact histogram specification-based application. Our algorithm relies on the ordering procedure based on the specialized variational approach. This variational method was shown to be superior to all other state-of-the art ordering algorithms in terms of faithful total strict ordering but not in speed. Indeed, the relevant functionals are in general difficult to minimize because their gradient is nearly flat over vast regions. In this paper, we propose a simple and fast fixed point algorithm to minimize these functionals. The fast convergence of our algorithm results from known analytical properties of the model. Our algorithm is equivalent to an iterative nonlinear filtering. Furthermore, we show that a particular form of the variational model gives rise to much faster convergence than other alternative forms. We demonstrate that only a few iterations of this filter yield almost the same pixel ordering as the minimizer. Thus, we apply only few iteration steps to obtain images, whose pixels can be ordered in a strict and faithful way. Numerical experiments confirm that our algorithm outperforms by far its main competitors. PMID:25347881

  11. How to incorporate generic refraction models into multistatic tracking algorithms

    NASA Astrophysics Data System (ADS)

    Crouse, D. F.

    The vast majority of literature published on target tracking ignores the effects of atmospheric refraction. When refraction is considered, the solutions are generally tailored to a simple exponential atmospheric refraction model. This paper discusses how arbitrary refraction models can be incorporated into tracking algorithms. Attention is paid to multistatic tracking problems, where uncorrected refractive effects can worsen track accuracy and consistency in centralized tracking algorithms, and can lead to difficulties in track-to-track association in distributed tracking filters. Monostatic and bistatic track initialization using refraction-corrupted measurements is discussed. The results are demonstrated using an exponential refractive model, though an arbitrary refraction profile can be substituted.

  12. Security market reaction to FDA fast track designations.

    PubMed

    Anderson, Christopher W; Zhang, Ying

    2010-01-01

    Pharmaceutical firms can apply for the Food and Drug Administration to 'fast track' research and de velopment on new drugs, accelerating clinical trials and expediting regulatory review required prior to marketing to consumers. We investigate security market reaction to more than 100 fast track designations from 1998 to 2004. Fast track designation appears to enhance investor recognition of firm value. Specifically, fast track designation coincides with abnormal trading volume and excess daily stock returns for sponsoring firms. Institutional ownership and analyst attention also increase. Market response is more pronounced for firms that are smaller, do not yet market products, and have low institutional ownership. PMID:21294437

  13. Fast Track'' nuclear thermal propulsion concept

    SciTech Connect

    Johnson, R.A.; Zweig, H.R. ); Cooper, M.H.; Wett, J. Jr. )

    1993-01-10

    The objective of the Space Exploration Initiative ( America at the Threshold...,'' 1991) is the exploration of Mars by man in the second decade of the 21st century. The NASA Fast Track'' approach (NASA-LeRC Presentation, 1992) could accelerate the manned exploration of Mars to 2007. NERVA-derived nuclear propulsion represents a viable near-term technology approach to accomplish the accelerated schedule. Key milestones in the progression to the manned Mars mission are (1) demonstration of TRL-6 for the man-rateable system by 1999, (2) a robotic lunar mission by 2000, (3) the first cargo mission to Mars by 2005, and (4) the piloted Mars mission in 2007. The Rocketdyne-Westinghouse concept for nuclear thermal propulsion to achieve these milestones combines the nuclear reactor technology of the Rover/NERVA programs and the state-of-the-art hardware designs from hydrogen-fueled rocket engine successes like the Space Shuttle Main Engine (SSME).

  14. Fast Fourier Transform algorithm design and tradeoffs

    NASA Technical Reports Server (NTRS)

    Kamin, Ray A., III; Adams, George B., III

    1988-01-01

    The Fast Fourier Transform (FFT) is a mainstay of certain numerical techniques for solving fluid dynamics problems. The Connection Machine CM-2 is the target for an investigation into the design of multidimensional Single Instruction Stream/Multiple Data (SIMD) parallel FFT algorithms for high performance. Critical algorithm design issues are discussed, necessary machine performance measurements are identified and made, and the performance of the developed FFT programs are measured. Fast Fourier Transform programs are compared to the currently best Cray-2 FFT program.

  15. Python algorithms in particle tracking microrheology

    PubMed Central

    2012-01-01

    Background Particle tracking passive microrheology relates recorded trajectories of microbeads, embedded in soft samples, to the local mechanical properties of the sample. The method requires intensive numerical data processing and tools allowing control of the calculation errors. Results We report the development of a software package collecting functions and scripts written in Python for automated and manual data processing, to extract viscoelastic information about the sample using recorded particle trajectories. The resulting program package analyzes the fundamental diffusion characteristics of particle trajectories and calculates the frequency dependent complex shear modulus using methods published in the literature. In order to increase conversion accuracy, segmentwise, double step, range-adaptive fitting and dynamic sampling algorithms are introduced to interpolate the data in a splinelike manner. Conclusions The presented set of algorithms allows for flexible data processing for particle tracking microrheology. The package presents improved algorithms for mean square displacement estimation, controlling effects of frame loss during recording, and a novel numerical conversion method using segmentwise interpolation, decreasing the conversion error from about 100% to the order of 1%. PMID:23186362

  16. Fast Track Teaching: Beginning the Experiment in Accelerated Leadership Development

    ERIC Educational Resources Information Center

    Churches, Richard; Hutchinson, Geraldine; Jones, Jeff

    2009-01-01

    This article provides an overview of the development of the Fast Track teaching programme and personalised nature of the training and support that has been delivered. Fast Track teacher promotion rates are compared to national statistics demonstrating significant progression for certain groups, particularly women. (Contains 3 tables and 3 figures.)

  17. Fast Track: A Language Arts Program for Middle School Gifted

    ERIC Educational Resources Information Center

    Schneider, Jean

    2008-01-01

    "Fast Track" is a pseudonym for an accelerated, advanced language arts program for verbally gifted and high potential students in grades 6-8. The critical thinking model used for "Fast Track" was gleaned from Coalition of Essential Schools founder Ted Sizer's Habits of Mind: significance, evidence, connections, perspective, and supposition, as…

  18. Fast regional readout CMOS Image Sensor for dynamic MLC tracking

    NASA Astrophysics Data System (ADS)

    Zin, H.; Harris, E.; Osmond, J.; Evans, P.

    2014-03-01

    Advanced radiotherapy techniques such as volumetric modulated arc therapy (VMAT) require verification of the complex beam delivery including tracking of multileaf collimators (MLC) and monitoring the dose rate. This work explores the feasibility of a prototype Complementary metal-oxide semiconductor Image Sensor (CIS) for tracking these complex treatments by utilising fast, region of interest (ROI) read out functionality. An automatic edge tracking algorithm was used to locate the MLC leaves edges moving at various speeds (from a moving triangle field shape) and imaged with various sensor frame rates. The CIS demonstrates successful edge detection of the dynamic MLC motion within accuracy of 1.0 mm. This demonstrates the feasibility of the sensor to verify treatment delivery involving dynamic MLC up to ~400 frames per second (equivalent to the linac pulse rate), which is superior to any current techniques such as using electronic portal imaging devices (EPID). CIS provides the basis to an essential real-time verification tool, useful in accessing accurate delivery of complex high energy radiation to the tumour and ultimately to achieve better cure rates for cancer patients.

  19. MATLAB tensor classes for fast algorithm prototyping.

    SciTech Connect

    Bader, Brett William; Kolda, Tamara Gibson

    2004-10-01

    Tensors (also known as mutidimensional arrays or N-way arrays) are used in a variety of applications ranging from chemometrics to psychometrics. We describe four MATLAB classes for tensor manipulations that can be used for fast algorithm prototyping. The tensor class extends the functionality of MATLAB's multidimensional arrays by supporting additional operations such as tensor multiplication. The tensor as matrix class supports the 'matricization' of a tensor, i.e., the conversion of a tensor to a matrix (and vice versa), a commonly used operation in many algorithms. Two additional classes represent tensors stored in decomposed formats: cp tensor and tucker tensor. We descibe all of these classes and then demonstrate their use by showing how to implement several tensor algorithms that have appeared in the literature.

  20. Real time tracking with a silicon telescope prototype using the "artificial retina" algorithm

    NASA Astrophysics Data System (ADS)

    Abba, A.; Bedeschi, F.; Caponio, F.; Cenci, R.; Citterio, M.; Coelli, S.; Fu, J.; Geraci, A.; Grizzuti, M.; Lusardi, N.; Marino, P.; Monti, M.; Morello, M. J.; Neri, N.; Ninci, D.; Petruzzo, M.; Piucci, A.; Punzi, G.; Ristori, L.; Spinella, F.; Stracka, S.; Tonelli, D.; Walsh, J.

    2016-07-01

    We present the first prototype of a silicon tracker using the artificial retina algorithm for fast track finding. The algorithm is inspired by the neurobiological mechanism of recognition of edges in mammals visual cortex. It is based on extensive parallelization and is implemented on commercial FPGAs allowing us to reconstruct real time tracks with offline-like quality and < 1 μs latencies. The practical device consists of a telescope with 8 single-sided silicon strip sensors and custom DAQ boards equipped with Xilinx Kintex 7 FPGAs that perform the readout of the sensors and the track reconstruction in real time.

  1. Automatic face detection and tracking based on Adaboost with camshift algorithm

    NASA Astrophysics Data System (ADS)

    Lin, Hui; Long, JianFeng

    2011-10-01

    With the development of information technology, video surveillance is widely used in security monitoring and identity recognition. For most of pure face tracking algorithms are hard to specify the initial location and scale of face automatically, this paper proposes a fast and robust method to detect and track face by combining adaboost with camshift algorithm. At first, the location and scale of face is specified by adaboost algorithm based on Haar-like features and it will be conveyed to the initial search window automatically. Then, we apply camshift algorithm to track face. The experimental results based on OpenCV software yield good results, even in some special circumstances, such as light changing and face rapid movement. Besides, by drawing out the tracking trajectory of face movement, some abnormal behavior events can be analyzed.

  2. Fastballs a Fast Track to 'Tommy John Surgery'?

    MedlinePlus

    ... 159058.html Fastballs a Fast Track to 'Tommy John Surgery'? Other pitches not linked to the elbow ... pitcher's risk of an elbow injury requiring "Tommy John surgery." "Our findings suggest that throwing a high ...

  3. Fast computation algorithms for speckle pattern simulation

    SciTech Connect

    Nascov, Victor; Samoilă, Cornel; Ursuţiu, Doru

    2013-11-13

    We present our development of a series of efficient computation algorithms, generally usable to calculate light diffraction and particularly for speckle pattern simulation. We use mainly the scalar diffraction theory in the form of Rayleigh-Sommerfeld diffraction formula and its Fresnel approximation. Our algorithms are based on a special form of the convolution theorem and the Fast Fourier Transform. They are able to evaluate the diffraction formula much faster than by direct computation and we have circumvented the restrictions regarding the relative sizes of the input and output domains, met on commonly used procedures. Moreover, the input and output planes can be tilted each to other and the output domain can be off-axis shifted.

  4. Fast-moving target tracking system based on CMOS image sensor

    NASA Astrophysics Data System (ADS)

    Miao, Zhun; Jiang, Jie; Zhang, Guangjun

    2008-10-01

    This paper introduces a fast-moving target tracking system based on CMOS (Complementary Metal-Oxygen Semiconductor) image sensor. A pipeline parallel architecture of region segmentation and first order moment algorithms on FPGA (Field Programmable Gate Array) platform enables driving the high frame rate CMOS image sensor and processing real-time images at the same time, extracting coordinates of the bright target spots in the high-rate consecutive image frames. In the end of this paper, an experiment proved that this system performs well in tracking fast-moving target in satisfying demand of speed and accuracy.

  5. Fast-Acquisition/Weak-Signal-Tracking GPS Receiver for HEO

    NASA Technical Reports Server (NTRS)

    Wintemitz, Luke; Boegner, Greg; Sirotzky, Steve

    2004-01-01

    A report discusses the technical background and design of the Navigator Global Positioning System (GPS) receiver -- . a radiation-hardened receiver intended for use aboard spacecraft. Navigator is capable of weak signal acquisition and tracking as well as much faster acquisition of strong or weak signals with no a priori knowledge or external aiding. Weak-signal acquisition and tracking enables GPS use in high Earth orbits (HEO), and fast acquisition allows for the receiver to remain without power until needed in any orbit. Signal acquisition and signal tracking are, respectively, the processes of finding and demodulating a signal. Acquisition is the more computationally difficult process. Previous GPS receivers employ the method of sequentially searching the two-dimensional signal parameter space (code phase and Doppler). Navigator exploits properties of the Fourier transform in a massively parallel search for the GPS signal. This method results in far faster acquisition times [in the lab, 12 GPS satellites have been acquired with no a priori knowledge in a Low-Earth-Orbit (LEO) scenario in less than one second]. Modeling has shown that Navigator will be capable of acquiring signals down to 25 dB-Hz, appropriate for HEO missions. Navigator is built using the radiation-hardened ColdFire microprocessor and housing the most computationally intense functions in dedicated field-programmable gate arrays. The high performance of the algorithm and of the receiver as a whole are made possible by optimizing computational efficiency and carefully weighing tradeoffs among the sampling rate, data format, and data-path bit width.

  6. Fast TracKer: A fast hardware track trigger for the ATLAS detector

    NASA Astrophysics Data System (ADS)

    Pandini, Carlo

    2016-07-01

    The trigger system at the ATLAS experiment is designed to lower the event rate occurring from the nominal bunch crossing rate of 40 MHz to about 1 kHz for a LHC luminosity of the order of 1034cm-2s-1. To achieve high background rejection while maintaining good efficiency for interesting physics signals, sophisticated algorithms are needed which require an extensive use of tracking information. The Fast TracKer (FTK) trigger system, part of the ATLAS trigger upgrade program, is a highly parallel hardware device designed to perform track-finding at 100 kHz. Modern, powerful Field Programmable Gate Arrays (FPGAs) form an important part of the system architecture, and the combinatorial problem of pattern recognition is solved by 8000 standard-cell ASICs used to implement an Associative Memory architecture. The availability of the tracking and subsequent vertex information within a short latency ensures robust selections and allows improved trigger performance for the most difficult signatures, such as b-jets and τ leptons.

  7. Experiments with conjugate gradient algorithms for homotopy curve tracking

    NASA Technical Reports Server (NTRS)

    Irani, Kashmira M.; Ribbens, Calvin J.; Watson, Layne T.; Kamat, Manohar P.; Walker, Homer F.

    1991-01-01

    There are algorithms for finding zeros or fixed points of nonlinear systems of equations that are globally convergent for almost all starting points, i.e., with probability one. The essence of all such algorithms is the construction of an appropriate homotopy map and then tracking some smooth curve in the zero set of this homotopy map. HOMPACK is a mathematical software package implementing globally convergent homotopy algorithms with three different techniques for tracking a homotopy zero curve, and has separate routines for dense and sparse Jacobian matrices. The HOMPACK algorithms for sparse Jacobian matrices use a preconditioned conjugate gradient algorithm for the computation of the kernel of the homotopy Jacobian matrix, a required linear algebra step for homotopy curve tracking. Here, variants of the conjugate gradient algorithm are implemented in the context of homotopy curve tracking and compared with Craig's preconditioned conjugate gradient method used in HOMPACK. The test problems used include actual large scale, sparse structural mechanics problems.

  8. Ultra fast-track extubation in heart transplant surgery patients

    PubMed Central

    Kianfar, Amir Abbas; Ahmadi, Zargham Hossein; Mirhossein, Seyed Mohsen; Jamaati, Hamidreza; Kashani, Babak Sharif; Mohajerani, Seyed Amir; Firoozi, Ehsan; Salehi, Farshid; Radmand, Golnar; Hashemian, Seyed Mohammadreza

    2015-01-01

    Background: Heart transplant surgeries using cardiopulmonary bypass (CPB) typically requires mechanical ventilation in intensive care units (ICU) in post-operation period. Ultra fast-track extubation (UFE) have been described in patients undergoing various cardiac surgeries. Aim: To determine the possibility of ultra-fast-track extubation instead of late extubation in post heart transplant patients. Materials and Methods: Patients randomly assigned into two groups; Ultra fast-track extubation (UFE) group was defined by extubation inside operating room right after surgery. Late extubation group was defined by patients who were not extubated in operating room and transferred to post operation cardiac care unit (CCU) to extubate. Results: The mean cardiopulmonary bypass time was 136.8 ± 25.7 minutes in ultra-fast extubation and 145.3 ± 29.8 minutes in late extubation patients (P > 0.05). Mechanical ventilation duration (days) was 0 days in ultra-fast and 2.31 ± 1.8 days in late extubation. Length of ICU stay was significantly higher in late extubation group (4.2 ± 1.2 days) than the UFE group (1.72 ± 1.5 days) (P = 0.02). In survival analysis there was no significant difference between ultra-fast and late extubation groups (Log-rank test, P = 0.9). Conclusions: Patients undergoing cardiac transplant could be managed with “ultra-fast-track extubation”, without increased morbidity and mortality. PMID:26157651

  9. Why Graduate Students Reject the Fast Track

    ERIC Educational Resources Information Center

    Mason, Mary Ann; Goulden, Marc; Frasch, Karie

    2009-01-01

    The authors recently completed an unparalleled survey, with more than eight thousand doctoral student respondents across the University of California system, and what they heard is worrisome: major research universities may be losing some of the most talented tenure-track academics before they even arrive. In the eyes of many doctoral students,…

  10. Energy Dynamics: A Fast Track Inquiry

    ERIC Educational Resources Information Center

    Schmidt, Stan M.; Hrynyshyn, Alec

    2004-01-01

    Students investigate energy conversions by collaborating to develop a free standing track of plastic tubing through which a ball bearing moves at the fastest possible speed. Friendly competition leads to discussion of what worked and did not work and to the identification and investigation of underlying principles. (Contains 4 charts.)

  11. Unbounded Binary Search for a Fast and Accurate Maximum Power Point Tracking

    NASA Astrophysics Data System (ADS)

    Kim, Yong Sin; Winston, Roland

    2011-12-01

    This paper presents a technique for maximum power point tracking (MPPT) of a concentrating photovoltaic system using cell level power optimization. Perturb and observe (P&O) has been a standard for an MPPT, but it introduces a tradeoff between the tacking speed and the accuracy of the maximum power delivered. The P&O algorithm is not suitable for a rapid environmental condition change by partial shading and self-shading due to its tracking time being linear to the length of the voltage range. Some of researches have been worked on fast tracking but they come with internal ad hoc parameters. In this paper, by using the proposed unbounded binary search algorithm for the MPPT, tracking time becomes a logarithmic function of the voltage search range without ad hoc parameters.

  12. A fast DFT algorithm using complex integer transforms

    NASA Technical Reports Server (NTRS)

    Reed, I. S.; Truong, T. K.

    1978-01-01

    Winograd's algorithm for computing the discrete Fourier transform is extended considerably for certain large transform lengths. This is accomplished by performing the cyclic convolution, required by Winograd's method, by a fast transform over certain complex integer fields. This algorithm requires fewer multiplications than either the standard fast Fourier transform or Winograd's more conventional algorithms.

  13. Nonlinear filter algorithm for opto-electronic target tracking

    NASA Astrophysics Data System (ADS)

    Xiong, Mao-tao; Song, Jian-xun; Wu, Qin-zhang

    2009-05-01

    At present in opto-electronic targets tracking, traditional accepted algorithms inevitably connect with linear errors. To improve the degraded performance of general algorithms, the Adaptive Unscented Particle Kalman Filter (AUPF) algorithm is proposed. The algorithm combines with Unscented Kalman Filter (UKF) to incorporate the most current observation datum and to generate the importance density function. Additionally, the Markov Chain Monte Carlo (MCMC) steps are adopted to counteract the problem of particles impoverishment caused by re-sampling step and thus the diversity of the particles is maintained. The AUPF algorithm reduces the nonlinear influence and improves the tracking accuracy of the opto-electronic targets tracking system. The analytic results of Monte Carlo simulation prove the AUPF algorithm is right and feasible, and it enhances the stability, the convergence rate and the accuracy of tracking system. The simulation results and algorithm provide a new approach for precise tracking of opto-electronic targets, they must have better applicative prospect in various engineering than the traditional tracking algorithms.

  14. A Fast Implementation of the ISOCLUS Algorithm

    NASA Technical Reports Server (NTRS)

    Memarsadeghi, Nargess; Mount, David M.; Netanyahu, Nathan S.; LeMoigne, Jacqueline

    2003-01-01

    (kn) time, where k denotes the current number of centers. Traditional techniques for accelerating nearest neighbor searching involve storing the k centers in a data structure. However, because of the iterative nature of the algorithm, this data structure would need to be rebuilt with each new iteration. Our approach is to store the data points in a kd-tree data structure. The assignment of points to nearest neighbors is carried out by a filtering process, which successively eliminates centers that can not possibly be the nearest neighbor for a given region of space. This algorithm is significantly faster, because large groups of data points can be assigned to their nearest center in a single operation. Preliminary results on a number of real Landsat datasets show that our revised ISOCLUS-like scheme runs about twice as fast.

  15. Modeling and performance analysis of GPS vector tracking algorithms

    NASA Astrophysics Data System (ADS)

    Lashley, Matthew

    This dissertation provides a detailed analysis of GPS vector tracking algorithms and the advantages they have over traditional receiver architectures. Standard GPS receivers use a decentralized architecture that separates the tasks of signal tracking and position/velocity estimation. Vector tracking algorithms combine the two tasks into a single algorithm. The signals from the various satellites are processed collectively through a Kalman filter. The advantages of vector tracking over traditional, scalar tracking methods are thoroughly investigated. A method for making a valid comparison between vector and scalar tracking loops is developed. This technique avoids the ambiguities encountered when attempting to make a valid comparison between tracking loops (which are characterized by noise bandwidths and loop order) and the Kalman filters (which are characterized by process and measurement noise covariance matrices) that are used by vector tracking algorithms. The improvement in performance offered by vector tracking is calculated in multiple different scenarios. Rule of thumb analysis techniques for scalar Frequency Lock Loops (FLL) are extended to the vector tracking case. The analysis tools provide a simple method for analyzing the performance of vector tracking loops. The analysis tools are verified using Monte Carlo simulations. Monte Carlo simulations are also used to study the effects of carrier to noise power density (C/N0) ratio estimation and the advantage offered by vector tracking over scalar tracking. The improvement from vector tracking ranges from 2.4 to 6.2 dB in various scenarios. The difference in the performance of the three vector tracking architectures is analyzed. The effects of using a federated architecture with and without information sharing between the receiver's channels are studied. A combination of covariance analysis and Monte Carlo simulation is used to analyze the performance of the three algorithms. The federated algorithm without

  16. A fast track to IAIMS: the Vanderbilt University strategy.

    PubMed

    Stead, W W; Baker, W; Harris, T R; Hodges, T M; Sittig, D F

    1992-01-01

    In July 1991, Vanderbilt University Medical Center (VUMC) initiated a fast track approach to the implementation of an Integrated Academic Information Management System (IAIMS). The fast track approach has four elements: 1) an integrated organizational structure combining various operational information management units and the academic informatics program into a single entity to enhance efficiency; 2) technology transfer and network access to remote resources in preference to de novo development; 3) parallel IAIMS planning and infrastructure construction; 4) restriction of the scope of the initial IAIMS to permit a manageable implementation project. The fast track approach is intended to provide a truly functional IAIMS within a time period (7 years) associated with other major construction projects such as the building of a replacement hospital. PMID:1336415

  17. Fast Markerless Tracking for Augmented Reality in Planar Environment

    NASA Astrophysics Data System (ADS)

    Basori, Ahmad Hoirul; Afif, Fadhil Noer; Almazyad, Abdulaziz S.; AbuJabal, Hamza Ali S.; Rehman, Amjad; Alkawaz, Mohammed Hazim

    2015-12-01

    Markerless tracking for augmented reality should not only be accurate but also fast enough to provide a seamless synchronization between real and virtual beings. Current reported methods showed that a vision-based tracking is accurate but requires high computational power. This paper proposes a real-time hybrid-based method for tracking unknown environments in markerless augmented reality. The proposed method provides collaboration of vision-based approach with accelerometers and gyroscopes sensors as camera pose predictor. To align the augmentation relative to camera motion, the tracking method is done by substituting feature-based camera estimation with combination of inertial sensors with complementary filter to provide more dynamic response. The proposed method managed to track unknown environment with faster processing time compared to available feature-based approaches. Moreover, the proposed method can sustain its estimation in a situation where feature-based tracking loses its track. The collaboration of sensor tracking managed to perform the task for about 22.97 FPS, up to five times faster than feature-based tracking method used as comparison. Therefore, the proposed method can be used to track unknown environments without depending on amount of features on scene, while requiring lower computational cost.

  18. A maximum power point tracking algorithm for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Nelatury, Sudarshan R.; Gray, Robert

    2013-05-01

    The voltage and current characteristic of a photovoltaic (PV) cell is highly nonlinear and operating a PV cell for maximum power transfer has been a challenge for a long time. Several techniques have been proposed to estimate and track the maximum power point (MPP) in order to improve the overall efficiency of a PV panel. A strategic use of the mean value theorem permits obtaining an analytical expression for a point that lies in a close neighborhood of the true MPP. But hitherto, an exact solution in closed form for the MPP is not published. This problem can be formulated analytically as a constrained optimization, which can be solved using the Lagrange method. This method results in a system of simultaneous nonlinear equations. Solving them directly is quite difficult. However, we can employ a recursive algorithm to yield a reasonably good solution. In graphical terms, suppose the voltage current characteristic and the constant power contours are plotted on the same voltage current plane, the point of tangency between the device characteristic and the constant power contours is the sought for MPP. It is subject to change with the incident irradiation and temperature and hence the algorithm that attempts to maintain the MPP should be adaptive in nature and is supposed to have fast convergence and the least misadjustment. There are two parts in its implementation. First, one needs to estimate the MPP. The second task is to have a DC-DC converter to match the given load to the MPP thus obtained. Availability of power electronics circuits made it possible to design efficient converters. In this paper although we do not show the results from a real circuit, we use MATLAB to obtain the MPP and a buck-boost converter to match the load. Under varying conditions of load resistance and irradiance we demonstrate MPP tracking in case of a commercially available solar panel MSX-60. The power electronics circuit is simulated by PSIM software.

  19. Motion object tracking algorithm using multi-cameras

    NASA Astrophysics Data System (ADS)

    Kong, Xiaofang; Chen, Qian; Gu, Guohua

    2015-09-01

    Motion object tracking is one of the most important research directions in computer vision. Challenges in designing a robust tracking method are usually caused by partial or complete occlusions on targets. However, motion object tracking algorithm based on multiple cameras according to the homography relation in three views can deal with this issue effectively since the information combining from multiple cameras in different views can make the target more complete and accurate. In this paper, a robust visual tracking algorithm based on the homography relations of three cameras in different views is presented to cope with the occlusion. First of all, being the main contribution of this paper, the motion object tracking algorithm based on the low-rank matrix representation under the framework of the particle filter is applied to track the same target in the public region respectively in different views. The target model and the occlusion model are established and an alternating optimization algorithm is utilized to solve the proposed optimization formulation while tracking. Then, we confirm the plane in which the target has the largest occlusion weight to be the principal plane and calculate the homography to find out the mapping relations between different views. Finally, the images of the other two views are projected into the main plane. By making use of the homography relation between different views, the information of the occluded target can be obtained completely. The proposed algorithm has been examined throughout several challenging image sequences, and experiments show that it overcomes the failure of the motion tracking especially under the situation of the occlusion. Besides, the proposed algorithm improves the accuracy of the motion tracking comparing with other state-of-the-art algorithms.

  20. An efficient central DOA tracking algorithm for multiple incoherently distributed sources

    NASA Astrophysics Data System (ADS)

    Hassen, Sonia Ben; Samet, Abdelaziz

    2015-12-01

    In this paper, we develop a new tracking method for the direction of arrival (DOA) parameters assuming multiple incoherently distributed (ID) sources. The new approach is based on a simple covariance fitting optimization technique exploiting the central and noncentral moments of the source angular power densities to estimate the central DOAs. The current estimates are treated as measurements provided to the Kalman filter that model the dynamic property of directional changes for the moving sources. Then, the covariance-fitting-based algorithm and the Kalman filtering theory are combined to formulate an adaptive tracking algorithm. Our algorithm is compared to the fast approximated power iteration-total least square-estimation of signal parameters via rotational invariance technique (FAPI-TLS-ESPRIT) algorithm using the TLS-ESPRIT method and the subspace updating via FAPI-algorithm. It will be shown that the proposed algorithm offers an excellent DOA tracking performance and outperforms the FAPI-TLS-ESPRIT method especially at low signal-to-noise ratio (SNR) values. Moreover, the performances of the two methods increase as the SNR values increase. This increase is more prominent with the FAPI-TLS-ESPRIT method. However, their performances degrade when the number of sources increases. It will be also proved that our method depends on the form of the angular distribution function when tracking the central DOAs. Finally, it will be shown that the more the sources are spaced, the more the proposed method can exactly track the DOAs.

  1. Edge-following algorithm for tracking geological features

    NASA Technical Reports Server (NTRS)

    Tietz, J. C.

    1977-01-01

    Sequential edge-tracking algorithm employs circular scanning to point permit effective real-time tracking of coastlines and rivers from earth resources satellites. Technique eliminates expensive high-resolution cameras. System might also be adaptable for application in monitoring automated assembly lines, inspecting conveyor belts, or analyzing thermographs, or x ray images.

  2. Automatic Tracking Algorithm in Coaxial Near-Infrared Laser Ablation Endoscope for Fetus Surgery

    NASA Astrophysics Data System (ADS)

    Hu, Yan; Yamanaka, Noriaki; Masamune, Ken

    2014-07-01

    This article reports a stable vessel object tracking method for the treatment of twin-to-twin transfusion syndrome based on our previous 2 DOF endoscope. During the treatment of laser coagulation, it is necessary to focus on the exact position of the target object, however it moves by the mother's respiratory motion and still remains a challenge to obtain and track the position precisely. In this article, an algorithm which uses features from accelerated segment test (FAST) to extract the features and optical flow as the object tracking method, is proposed to deal with above problem. Further, we experimentally simulate the movement due to the mother's respiration, and the results of position errors and similarity verify the effectiveness of the proposed tracking algorithm for laser ablation endoscopy in-vitro and under water considering two influential factors. At average, the errors are about 10 pixels and the similarity over 0.92 are obtained in the experiments.

  3. Education For All (EFA) - Fast Track Initiative Progress Report 30046

    ERIC Educational Resources Information Center

    World Bank Education Advisory Service, 2004

    2004-01-01

    Launched in June 2002, the Education For All-Fast Track Initiative (FTI) is a performance-based program focusing on the implementation of sustainable policies in support of universal primary completion (UPC) and the required resource mobilization. During its twenty months of implementation, FTI has delivered on results, which give reason for…

  4. Fast Track: Elementary School. What Works Clearinghouse Intervention Report

    ERIC Educational Resources Information Center

    What Works Clearinghouse, 2014

    2014-01-01

    "Fast Track" is a comprehensive intervention designed to reduce conduct problems and promote academic, behavioral, and social improvement. The program's components include the "Promoting Alternative THinking Strategies" curriculum, parent groups, parent-child sharing time, child social skills training, home visiting, child…

  5. Fast Track to Success: Top Young Trainers 2012

    ERIC Educational Resources Information Center

    Freifeld, Lorri

    2012-01-01

    Supercharged. High-performers. Leaders of the pack. This article presents "Training" magazine's 2012 Top Young Trainers--those high-potential training professionals who are on the fast track to success. For the fifth year, "Training" magazine is pleased to recognize the outstanding talents, accomplishments, and leadership exhibited by 40 learning…

  6. Internal model control of a fast steering mirror for electro-optical fine tracking

    NASA Astrophysics Data System (ADS)

    Xia, Yun-xia; Bao, Qi-liang; Wu, Qiong-yan

    2010-11-01

    The objective of this research is to develop advanced control methods to improve the bandwidth and tracking precision of the electro-optical fine tracking system using a fast steering mirror (FSM). FSM is the most important part in this control system. The model of FSM is established at the beginning of this paper. Compared with the electro-optical fine tracking system with ground based platform, the electro-optical fine tracking system with movement based platform must be a wide bandwidth and a robustness system. An advanced control method based on internal model control law is developed for electro-optical fine tracking system. The IMC is an advanced algorithm. Theoretically, it can eliminate disturbance completely and make sure output equals to input even there is model error. Moreover, it separates process to the system dynamic characteristic and the object perturbation. Compared with the PID controller, the controller is simpler and the parameter regulation is more convenient and the system is more robust. In addition, we design an improved structure based on classic IMC. The tracking error of the two-port control system is much better than which of the classic IMC. The simulation results indicate that the electro-optical control system based on the internal model control algorithm is very effective. It shows a better performance at the tracing precision and the disturbance suppresses. Thus a new method is provided for the high-performance electro-optical fine tracking system.

  7. Fast tracking mode predictive centroiding scheme

    NASA Astrophysics Data System (ADS)

    Rehman, Masood-Ur; Fang, Jiancheng; Saffih, Faycal; Quan, Wei

    2008-10-01

    The autonomous star trackers, using charge couple device CCD camera, or active pixel sensor APS, as natural sensors for optical input, has assumed a permanent position. This is due to their highly accurate attitude determination, small size, light weight and simple functionality, making them devices of choice in nearly all modern space vehicles especially for Nano-satellites. In all star trackers, star centroiding is a fundamental process necessary for pattern recognition. In this paper, a new method is presented, which predicts centers of regions of star locations, in successive image frames, from the current knowledge of boresight direction, which is updated successively. This method is very attractive for hardware implementation using APS imagers known for their random accessibility feature lacked in CCD's. The big advantage of this method is that it does not need pattern recognition, thus making it fast. This reduction of computational budget, power consumption and time, added to the capability of incorporating them in APS imagers, is appealing to Nano-satellites navigational instrumentation.

  8. Multiple Object Tracking Using the Shortest Path Faster Association Algorithm

    PubMed Central

    Liu, Heping; Liu, Huaping; Yang, Bin

    2014-01-01

    To solve the persistently multiple object tracking in cluttered environments, this paper presents a novel tracking association approach based on the shortest path faster algorithm. First, the multiple object tracking is formulated as an integer programming problem of the flow network. Then we relax the integer programming to a standard linear programming problem. Therefore, the global optimum can be quickly obtained using the shortest path faster algorithm. The proposed method avoids the difficulties of integer programming, and it has a lower worst-case complexity than competing methods but better robustness and tracking accuracy in complex environments. Simulation results show that the proposed algorithm takes less time than other state-of-the-art methods and can operate in real time. PMID:25215322

  9. Acquisition and track algorithms for the Astros star tracker

    NASA Technical Reports Server (NTRS)

    Shalom, E.; Alexander, J. W.; Stanton, R. H.

    1985-01-01

    The Astros star tracker has been designed for an employment with the Space Shuttle. An achievement of the performance levels needed has required critical trade-offs between the hardware design and the control algorithms. This paper provides a description of the development of the acquisition and track algorithms. Attention is given to an Astros system overview, a system firmware description, cluster evaluation, guide star selection, exposure time determination, video data input, update interval timing, exposure time sequencing full frame video A/D conversion, analog threshold for acquisition, minimum threshold determination, and the theoretical basis for the track algorithm.

  10. Video tracking algorithm of long-term experiment using stand-alone recording system

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Jen; Li, Yan-Chay; Huang, Ke-Nung; Jen, Sun-Lon; Young, Ming-Shing

    2008-08-01

    Many medical and behavioral applications require the ability to monitor and quantify the behavior of small animals. In general these animals are confined in small cages. Often these situations involve very large numbers of cages. Modern research facilities commonly monitor simultaneously thousands of animals over long periods of time. However, conventional systems require one personal computer per monitoring platform, which is too complex, expensive, and increases power consumption for large laboratory applications. This paper presents a simplified video tracking algorithm for long-term recording using a stand-alone system. The feature of the presented tracking algorithm revealed that computation speed is very fast data storage requirements are small, and hardware requirements are minimal. The stand-alone system automatically performs tracking and saving acquired data to a secure digital card. The proposed system is designed for video collected at a 640×480 pixel with 16 bit color resolution. The tracking result is updated every 30 frames/s. Only the locomotive data are stored. Therefore, the data storage requirements could be minimized. In addition, detection via the designed algorithm uses the Cb and Cr values of a colored marker affixed to the target to define the tracked position and allows multiobject tracking against complex backgrounds. Preliminary experiment showed that such tracking information stored by the portable and stand-alone system could provide comprehensive information on the animal's activity.

  11. Novel automatic eye detection and tracking algorithm

    NASA Astrophysics Data System (ADS)

    Ghazali, Kamarul Hawari; Jadin, Mohd Shawal; Jie, Ma; Xiao, Rui

    2015-04-01

    The eye is not only one of the most complex but also the most important sensory organ of the human body. Eye detection and eye tracking are basement and hot issue in image processing. A non-invasive eye location and eye tracking is promising for hands-off gaze-based human-computer interface, fatigue detection, instrument control by paraplegic patients and so on. For this purpose, an innovation work frame is proposed to detect and tracking eye in video sequence in this paper. The contributions of this work can be divided into two parts. The first contribution is that eye filters were trained which can detect eye location efficiently and accurately without constraints on the background and skin colour. The second contribution is that a framework of tracker based on sparse representation and LK optic tracker were built which can track eye without constraint on eye status. The experimental results demonstrate the accuracy aspects and the real-time applicability of the proposed approach.

  12. Divergence detectors for multitarget tracking algorithms

    NASA Astrophysics Data System (ADS)

    Mahler, Ronald

    2013-05-01

    Single-target tracking filters will typically diverge when their internal measurement or motion models deviate too much from the actual models. Niu, Varshney, Alford, Bubalo, Jones, and Scalzo have proposed a metric-- the normalized innovation squared (NIS)--that recursively estimates the degree of nonlinearity in a single-target tracking problem by detecting filter divergence. This paper establishes the following: (1) NIS can be extended to generalized NIS (GNIS), which addresses more general nonlinearities; (2) NIS and GNIS are actually anomaly detectors, rather than filter-divergence detectors; (3) NIS can be heuristically generalized to a multitarget NIS (MNIS) metric; (4) GNIS also can be rigorously extended to multitarget problems via the multitarget GNIS (MGNIS); (5) explicit, computationally tractable formulas for MGNIS can be derived for use with CPHD and PHD filters; and thus (6) these formulas can be employed as anomaly detectors for use with these filters.

  13. A Novel Tracking Algorithm via Feature Points Matching

    PubMed Central

    Luo, Nan; Sun, Quansen; Chen, Qiang; Ji, Zexuan; Xia, Deshen

    2015-01-01

    Visual target tracking is a primary task in many computer vision applications and has been widely studied in recent years. Among all the tracking methods, the mean shift algorithm has attracted extraordinary interest and been well developed in the past decade due to its excellent performance. However, it is still challenging for the color histogram based algorithms to deal with the complex target tracking. Therefore, the algorithms based on other distinguishing features are highly required. In this paper, we propose a novel target tracking algorithm based on mean shift theory, in which a new type of image feature is introduced and utilized to find the corresponding region between the neighbor frames. The target histogram is created by clustering the features obtained in the extraction strategy. Then, the mean shift process is adopted to calculate the target location iteratively. Experimental results demonstrate that the proposed algorithm can deal with the challenging tracking situations such as: partial occlusion, illumination change, scale variations, object rotation and complex background clutter. Meanwhile, it outperforms several state-of-the-art methods. PMID:25617769

  14. An automatic and fast centerline extraction algorithm for virtual colonoscopy.

    PubMed

    Jiang, Guangxiang; Gu, Lixu

    2005-01-01

    This paper introduces a new refined centerline extraction algorithm, which is based on and significantly improved from distance mapping algorithms. The new approach include three major parts: employing a colon segmentation method; designing and realizing a fast Euclidean Transform algorithm and inducting boundary voxels cutting (BVC) approach. The main contribution is the BVC processing, which greatly speeds up the Dijkstra algorithm and improves the whole performance of the new algorithm. Experimental results demonstrate that the new centerline algorithm was more efficient and accurate comparing with existing algorithms. PMID:17281406

  15. Quantitative comparison of algorithms for tracking single fluorescent particles.

    PubMed

    Cheezum, M K; Walker, W F; Guilford, W H

    2001-10-01

    Single particle tracking has seen numerous applications in biophysics, ranging from the diffusion of proteins in cell membranes to the movement of molecular motors. A plethora of computer algorithms have been developed to monitor the sub-pixel displacement of fluorescent objects between successive video frames, and some have been claimed to have "nanometer" resolution. To date, there has been no rigorous comparison of these algorithms under realistic conditions. In this paper, we quantitatively compare specific implementations of four commonly used tracking algorithms: cross-correlation, sum-absolute difference, centroid, and direct Gaussian fit. Images of fluorescent objects ranging in size from point sources to 5 microm were computer generated with known sub-pixel displacements. Realistic noise was added and the above four algorithms were compared for accuracy and precision. We found that cross-correlation is the most accurate algorithm for large particles. However, for point sources, direct Gaussian fit to the intensity distribution is the superior algorithm in terms of both accuracy and precision, and is the most robust at low signal-to-noise. Most significantly, all four algorithms fail as the signal-to-noise ratio approaches 4. We judge direct Gaussian fit to be the best algorithm when tracking single fluorophores, where the signal-to-noise is frequently near 4. PMID:11566807

  16. Three hypothesis algorithm with occlusion reasoning for multiple people tracking

    NASA Astrophysics Data System (ADS)

    Reta, Carolina; Altamirano, Leopoldo; Gonzalez, Jesus A.; Medina-Carnicer, Rafael

    2015-01-01

    This work proposes a detection-based tracking algorithm able to locate and keep the identity of multiple people, who may be occluded, in uncontrolled stationary environments. Our algorithm builds a tracking graph that models spatio-temporal relationships among attributes of interacting people to predict and resolve partial and total occlusions. When a total occlusion occurs, the algorithm generates various hypotheses about the location of the occluded person considering three cases: (a) the person keeps the same direction and speed, (b) the person follows the direction and speed of the occluder, and (c) the person remains motionless during occlusion. By analyzing the graph, our algorithm can detect trajectories produced by false alarms and estimate the location of missing or occluded people. Our algorithm performs acceptably under complex conditions, such as partial visibility of individuals getting inside or outside the scene, continuous interactions and occlusions among people, wrong or missing information on the detection of persons, as well as variation of the person's appearance due to illumination changes and background-clutter distracters. Our algorithm was evaluated on test sequences in the field of intelligent surveillance achieving an overall precision of 93%. Results show that our tracking algorithm outperforms even trajectory-based state-of-the-art algorithms.

  17. An enhanced fast scanning algorithm for image segmentation

    NASA Astrophysics Data System (ADS)

    Ismael, Ahmed Naser; Yusof, Yuhanis binti

    2015-12-01

    Segmentation is an essential and important process that separates an image into regions that have similar characteristics or features. This will transform the image for a better image analysis and evaluation. An important benefit of segmentation is the identification of region of interest in a particular image. Various algorithms have been proposed for image segmentation and this includes the Fast Scanning algorithm which has been employed on food, sport and medical images. It scans all pixels in the image and cluster each pixel according to the upper and left neighbor pixels. The clustering process in Fast Scanning algorithm is performed by merging pixels with similar neighbor based on an identified threshold. Such an approach will lead to a weak reliability and shape matching of the produced segments. This paper proposes an adaptive threshold function to be used in the clustering process of the Fast Scanning algorithm. This function used the gray'value in the image's pixels and variance Also, the level of the image that is more the threshold are converted into intensity values between 0 and 1, and other values are converted into intensity values zero. The proposed enhanced Fast Scanning algorithm is realized on images of the public and private transportation in Iraq. Evaluation is later made by comparing the produced images of proposed algorithm and the standard Fast Scanning algorithm. The results showed that proposed algorithm is faster in terms the time from standard fast scanning.

  18. Vehicle tracking algorithm based on GPS and map-matching

    NASA Astrophysics Data System (ADS)

    Guan, Guixia; Yan, Lei; Chen, Jiabin; Wu, Taixia

    2008-10-01

    In the land vehicle positioning and tracking system, the vehicle moving route is sometimes positioned outside the vehicle running road because of the GPS positioning errors. It may cause the tracking system unavailable. In order to improve the positioning accuracy of vehicle tracking system, a current statistical model is employed as the vehicle moving model. At the same time, the map-matching algorithm with the nearest location and the suitable moving angle is proposed to amend GPS measured data. The algorithm can determine the best matching road by making full use of the road geographic information of electronic map. Simulation results show that the vehicle tracking system has high positioning accuracy besides the navigation function.

  19. Robust illumination-invariant tracking algorithm based on HOGs

    NASA Astrophysics Data System (ADS)

    Miramontes-Jaramillo, Daniel; Kober, Vitaly; Díaz-Ramírez, Víctor H.

    2015-09-01

    Common tracking systems are usually affected by environmental and technical interferences such as non-uniform illumination, sensors' noise, geometrical scene distortion, etc. Among these issues, the former is particularly interesting because it destroys important spatial characteristics of objects in observed scenes. We propose a two-step tracking algorithm: first, preprocessing locally normalizes the illumination difference between the target object and observed frames; second, the normalized object is tracked by means of a designed template structure based on histograms of oriented gradients and kinematic prediction model. The algorithm performance is tested in terms of recognition and localization errors in real scenarios. In order to achieve high rate of the processing, we use GPU parallel processing technologies. Finally, our algorithm is compared with other state-of-the-art trackers.

  20. Silicon vertex tracker: a fast precise tracking trigger for CDF

    NASA Astrophysics Data System (ADS)

    Ashmanskas, W.; Bardi, A.; Bari, M.; Belforte, S.; Berryhill, J.; Bogdan, M.; Cerri, A.; Clark, A. G.; Chlanchidze, G.; Condorelli, R.; Culbertson, R.; Dell'Orso, M.; Donati, S.; Frisch, H. J.; Galeotti, S.; Giannetti, P.; Glagolev, V.; Leger, A.; Meschi, E.; Morsani, F.; Nakaya, T.; Punzi, G.; Ristori, L.; Sanders, H.; Semenov, A.; Signorelli, G.; Shochet, M.; Speer, T.; Spinella, F.; Wilson, P.; Wu, Xin; Zanetti, A. M.

    2000-06-01

    The Silicon Vertex Tracker (SVT), currently being built for the CDF II experiment, is a hardware device that reconstructs 2-D tracks online using measurements from the Silicon Vertex Detector (SVXII) and the Central Outer Tracker (COT). The precise measurement of the impact parameter of the SVT tracks will allow, for the first time in a hadron collider environment, to trigger on events containing B hadrons that are very important for many studies, such as CP violation in the b sector and searching for new heavy particles decaying to b b¯ . In this report we describe the overall architecture, algorithms and the hardware implementation of the SVT.

  1. Visual tracking method based on cuckoo search algorithm

    NASA Astrophysics Data System (ADS)

    Gao, Ming-Liang; Yin, Li-Ju; Zou, Guo-Feng; Li, Hai-Tao; Liu, Wei

    2015-07-01

    Cuckoo search (CS) is a new meta-heuristic optimization algorithm that is based on the obligate brood parasitic behavior of some cuckoo species in combination with the Lévy flight behavior of some birds and fruit flies. It has been found to be efficient in solving global optimization problems. An application of CS is presented to solve the visual tracking problem. The relationship between optimization and visual tracking is comparatively studied and the parameters' sensitivity and adjustment of CS in the tracking system are experimentally studied. To demonstrate the tracking ability of a CS-based tracker, a comparative study of tracking accuracy and speed of the CS-based tracker with six "state-of-art" trackers, namely, particle filter, meanshift, PSO, ensemble tracker, fragments tracker, and compressive tracker are presented. Comparative results show that the CS-based tracker outperforms the other trackers.

  2. Implementation and analysis of a fast backprojection algorithm

    NASA Astrophysics Data System (ADS)

    Gorham, LeRoy A.; Majumder, Uttam K.; Buxa, Peter; Backues, Mark J.; Lindgren, Andrew C.

    2006-05-01

    The convolution backprojection algorithm is an accurate synthetic aperture radar imaging technique, but it has seen limited use in the radar community due to its high computational costs. Therefore, significant research has been conducted for a fast backprojection algorithm, which surrenders some image quality for increased computational efficiency. This paper describes an implementation of both a standard convolution backprojection algorithm and a fast backprojection algorithm optimized for use on a Linux cluster and a field-programmable gate array (FPGA) based processing system. The performance of the different implementations is compared using synthetic ideal point targets and the SPIE XPatch Backhoe dataset.

  3. Fast non-iterative calibration of an external motion tracking device

    PubMed Central

    Zahneisen, Benjamin; Lovell-Smith, Chris; Herbst, Michael; Zaitsev, Maxim; Speck, Oliver; Armstrong, Brian; Ernst, Thomas

    2013-01-01

    Purpose Prospective motion correction of MR scans commonly uses an external device, such as a camera, to track the pose of the organ of interest. However, in order for external tracking data to be translated into the MR scanner reference frame, the pose of the camera relative to the MR scanner must be known accurately. Here, we describe a fast, accurate, non-iterative technique to determine the position of an external tracking device de novo relative to the MR reference frame. Theory and Methods The method relies on imaging a sparse object that allows simultaneous tracking of arbitrary rigid body transformations in the reference frame of the MRI machine and that of the external tracking device. Results Large motions in the MRI reference frame can be measured using a sparse phantom with an accuracy of 0.2 mm, or approximately 1/10 of the voxel size. By using a dual quaternion algorithm to solve the calibration problem, a good camera calibration can be achieved with fewer than 6 measurements. Further refinements can be achieved by applying the method iteratively and using motion correction feedback. Conclusion Independent tracking of a series of movements in two reference frames allows for an analytical solution to the hand-eye-calibration problem for various motion tracking setups in MRI. PMID:23788117

  4. A fast quaternion-based orientation optimizer via virtual rotation for human motion tracking.

    PubMed

    Lee, Jung Keun; Park, Edward J

    2009-05-01

    For real-time ambulatory human motion tracking with low-cost inertial/magnetic sensors, a computationally efficient and robust algorithm for estimating orientation is critical. This paper presents a quaternion-based orientation optimizer for tracking human body motion, using triaxis rate gyro, accelerometer, and magnetometer signals. The proposed optimizer uses a Gauss-Newton (G-N) method for finding the best-fit quaternion. In order to decrease the computing time, the optimizer is formulated using a virtual rotation concept that allows very fast quaternion updates compared to the conventional G-N method. In addition, to guard against the effects of fast body motions and temporary ferromagnetic disturbances, a situational measurement vector selection procedure is adopted in conjunction with the G-N optimizer. The accuracy of orientation estimates is validated experimentally, using arm motion trials. PMID:19473934

  5. Solar Load Voltage Tracking for Water Pumping: An Algorithm

    NASA Astrophysics Data System (ADS)

    Kappali, M.; Udayakumar, R. Y.

    2014-07-01

    Maximum power is to be harnessed from solar photovoltaic (PV) panel to minimize the effective cost of solar energy. This is accomplished by maximum power point tracking (MPPT). There are different methods to realise MPPT. This paper proposes a simple algorithm to implement MPPT lv method in a closed loop environment for centrifugal pump driven by brushed PMDC motor. Simulation testing of the algorithm is done and the results are found to be encouraging and supportive of the proposed method MPPT lv .

  6. Ground maneuvering target tracking based on the strong tracking and the cubature Kalman filter algorithms

    NASA Astrophysics Data System (ADS)

    Gao, Min; Zhang, Heng; Zhou, Yulong; Zhang, Baoquan

    2016-03-01

    In an effort to improve the tracking accuracy of the ground maneuvering target in infrared images, a method is proposed based on the strong tracking filter (STF) and the cubature Kalman filter (CKF) algorithms. In this method, the fading factor is introduced from the STF algorithm and is calculated by transforming the nonlinear measurement variance matrix to be linear approximately, and then the fading factor is used to correct the prediction error covariance matrix (PECM) of CKF, so that the gain matrix can be adjusted at real time and hence the tracking ability of the maneuvering target could be improved. After the digital simulation experiment, it is shown that, comparing with CKF and the unscented Kalman filter algorithms, the average tracking accuracy of the location is increased by more than 20% with the target velocity under 20 m/s and acceleration under 5 m/s2, and it can even be increased by 50% when the target step maneuver occurs. With the tracking experiment on the real infrared tank images, it can be concluded that the target could be tracked stably by the proposed method, and the maximum tracking error is not more than 8 pixels even though the 180 deg turning takes place.

  7. Fast algorithm for peptide sequencing by mass spectroscopy.

    PubMed

    Bartels, C

    1990-01-01

    An automatic algorithm for sequencing polypeptides from fast atom bombardment tandem mass spectra is presented.Based on graph theory considerations it finds the most probable sequences, even if the amino acid composition is unknown, by scoring mass differences. The algorithm is fast as the computing time increases by less than the square of the number of amino acids. Pairs of two or three amino acids are proposed to explain the gap if peaks are missing. PMID:24730078

  8. Real-Time Robust Tracking for Motion Blur and Fast Motion via Correlation Filters.

    PubMed

    Xu, Lingyun; Luo, Haibo; Hui, Bin; Chang, Zheng

    2016-01-01

    Visual tracking has extensive applications in intelligent monitoring and guidance systems. Among state-of-the-art tracking algorithms, Correlation Filter methods perform favorably in robustness, accuracy and speed. However, it also has shortcomings when dealing with pervasive target scale variation, motion blur and fast motion. In this paper we proposed a new real-time robust scheme based on Kernelized Correlation Filter (KCF) to significantly improve performance on motion blur and fast motion. By fusing KCF and STC trackers, our algorithm also solve the estimation of scale variation in many scenarios. We theoretically analyze the problem for CFs towards motions and utilize the point sharpness function of the target patch to evaluate the motion state of target. Then we set up an efficient scheme to handle the motion and scale variation without much time consuming. Our algorithm preserves the properties of KCF besides the ability to handle special scenarios. In the end extensive experimental results on benchmark of VOT datasets show our algorithm performs advantageously competed with the top-rank trackers. PMID:27618046

  9. From the Fast Track to the Fast Lane--To What?

    ERIC Educational Resources Information Center

    Weininger, Otto

    1990-01-01

    Young children are being fast tracked at early age because of pressures from parents, schools, society, and media. One result is troubled teenagers who experience stress of these pressures without having adult means to cope with them. Time spent with parents and in play activities are activities that help children to gain security, happiness, and…

  10. A baseline algorithm for face detection and tracking in video

    NASA Astrophysics Data System (ADS)

    Manohar, Vasant; Soundararajan, Padmanabhan; Korzhova, Valentina; Boonstra, Matthew; Goldgof, Dmitry; Kasturi, Rangachar

    2007-10-01

    Establishing benchmark datasets, performance metrics and baseline algorithms have considerable research significance in gauging the progress in any application domain. These primarily allow both users and developers to compare the performance of various algorithms on a common platform. In our earlier works, we focused on developing performance metrics and establishing a substantial dataset with ground truth for object detection and tracking tasks (text and face) in two video domains -- broadcast news and meetings. In this paper, we present the results of a face detection and tracking algorithm on broadcast news videos with the objective of establishing a baseline performance for this task-domain pair. The detection algorithm uses a statistical approach that was originally developed by Viola and Jones and later extended by Lienhart. The algorithm uses a feature set that is Haar-like and a cascade of boosted decision tree classifiers as a statistical model. In this work, we used the Intel Open Source Computer Vision Library (OpenCV) implementation of the Haar face detection algorithm. The optimal values for the tunable parameters of this implementation were found through an experimental design strategy commonly used in statistical analyses of industrial processes. Tracking was accomplished as continuous detection with the detected objects in two frames mapped using a greedy algorithm based on the distances between the centroids of bounding boxes. Results on the evaluation set containing 50 sequences (~ 2.5 mins.) using the developed performance metrics show good performance of the algorithm reflecting the state-of-the-art which makes it an appropriate choice as the baseline algorithm for the problem.

  11. [A tracking algorithm for live mitochondria in fluorescent microscopy images].

    PubMed

    Xu, Junmei; Li, Yang; Du, Sidan; Zhao, Kanglian

    2012-04-01

    Quantitative analysis of biological image data generally involves the detection of many pixel spots. In live mitochondria video image, for which fluorescent microscopy is often used, the signal-to-noise ratio (SNR) can be extremely low, making the detection and tracking of mitochondria particle difficult. It is especially not easy to get the movement curve when the movement of the mitochondria involves its self-move and the motion caused by the neuron. An tracking algorithm for live mitochondria is proposed in this paper. First the whole image sequence is frame-to-frame registered, in which the edge corners are chosen to be the feature points. Then the mitochondria particles are tracked by frame-to-frame displacement vector. The algorithm proposed has been applied to the dynamic image sequence including neuron and mitochondria, saving time without manually picking up the feature points. It provides an new method and reference for medical image processing and biotechnological research. PMID:22616189

  12. Multi-expert tracking algorithm based on improved compressive tracker

    NASA Astrophysics Data System (ADS)

    Feng, Yachun; Zhang, Hong; Yuan, Ding

    2015-12-01

    Object tracking is a challenging task in computer vision. Most state-of-the-art methods maintain an object model and update the object model by using new examples obtained incoming frames in order to deal with the variation in the appearance. It will inevitably introduce the model drift problem into the object model updating frame-by-frame without any censorship mechanism. In this paper, we adopt a multi-expert tracking framework, which is able to correct the effect of bad updates after they happened such as the bad updates caused by the severe occlusion. Hence, the proposed framework exactly has the ability which a robust tracking method should process. The expert ensemble is constructed of a base tracker and its formal snapshot. The tracking result is produced by the current tracker that is selected by means of a simple loss function. We adopt an improved compressive tracker as the base tracker in our work and modify it to fit the multi-expert framework. The proposed multi-expert tracking algorithm significantly improves the robustness of the base tracker, especially in the scenes with frequent occlusions and illumination variations. Experiments on challenging video sequences with comparisons to several state-of-the-art trackers demonstrate the effectiveness of our method and our tracking algorithm can run at real-time.

  13. Fast feature identification for holographic tracking: the orientation alignment transform.

    PubMed

    Krishnatreya, Bhaskar Jyoti; Grier, David G

    2014-06-01

    The concentric fringe patterns created by features in holograms may be associated with a complex-valued orientational order field. Convolution with an orientational alignment operator then identifies centers of symmetry that correspond to the two-dimensional positions of the features. Feature identification through orientational alignment is reminiscent of voting algorithms such as Hough transforms, but may be implemented with fast convolution methods, and so can be orders of magnitude faster. PMID:24921472

  14. Fast algorithms for computing isogenies between elliptic curves

    NASA Astrophysics Data System (ADS)

    Bostan, A.; Morain, F.; Salvy, B.; Schost, E.

    2008-09-01

    We survey algorithms for computing isogenies between elliptic curves defined over a field of characteristic either 0 or a large prime. We introduce a new algorithm that computes an isogeny of degree ell ( ell different from the characteristic) in time quasi-linear with respect to ell E This is based in particular on fast algorithms for power series expansion of the Weierstrass wp -function and related functions.

  15. Fast algorithms for transport models. Final report

    SciTech Connect

    Manteuffel, T.A.

    1994-10-01

    This project has developed a multigrid in space algorithm for the solution of the S{sub N} equations with isotropic scattering in slab geometry. The algorithm was developed for the Modified Linear Discontinuous (MLD) discretization in space which is accurate in the thick diffusion limit. It uses a red/black two-cell {mu}-line relaxation. This relaxation solves for all angles on two adjacent spatial cells simultaneously. It takes advantage of the rank-one property of the coupling between angles and can perform this inversion in O(N) operations. A version of the multigrid in space algorithm was programmed on the Thinking Machines Inc. CM-200 located at LANL. It was discovered that on the CM-200 a block Jacobi type iteration was more efficient than the block red/black iteration. Given sufficient processors all two-cell block inversions can be carried out simultaneously with a small number of parallel steps. The bottleneck is the need for sums of N values, where N is the number of discrete angles, each from a different processor. These are carried out by machine intrinsic functions and are well optimized. The overall algorithm has computational complexity O(log(M)), where M is the number of spatial cells. The algorithm is very efficient and represents the state-of-the-art for isotropic problems in slab geometry. For anisotropic scattering in slab geometry, a multilevel in angle algorithm was developed. A parallel version of the multilevel in angle algorithm has also been developed. Upon first glance, the shifted transport sweep has limited parallelism. Once the right-hand-side has been computed, the sweep is completely parallel in angle, becoming N uncoupled initial value ODE`s. The author has developed a cyclic reduction algorithm that renders it parallel with complexity O(log(M)). The multilevel in angle algorithm visits log(N) levels, where shifted transport sweeps are performed. The overall complexity is O(log(N)log(M)).

  16. Application of fast BLMS algorithm in acoustic echo cancellation

    NASA Astrophysics Data System (ADS)

    Zhao, Yue; Li, Nian Q.

    2013-03-01

    The acoustic echo path is usually very long and ranges from several hundreds to few thousands of taps. Frequency domain adaptive filter provides a solution to acoustic echo cancellation by means of resulting a significant reduction in the computational burden. In this paper, fast BLMS (Block Least-Mean-Square) algorithm in frequency domain is realized by using fast FFT technology. The adaptation of filter parameters is actually performed in the frequency domain. The proposed algorithm can ensure convergence with high speed and reduce computational complexity. Simulation results indicate that the algorithm demonstrates good performance for acoustic echo cancellation in communication systems.

  17. A hybrid fast Hankel transform algorithm for electromagnetic modeling

    USGS Publications Warehouse

    Anderson, W.L.

    1989-01-01

    A hybrid fast Hankel transform algorithm has been developed that uses several complementary features of two existing algorithms: Anderson's digital filtering or fast Hankel transform (FHT) algorithm and Chave's quadrature and continued fraction algorithm. A hybrid FHT subprogram (called HYBFHT) written in standard Fortran-77 provides a simple user interface to call either subalgorithm. The hybrid approach is an attempt to combine the best features of the two subalgorithms to minimize the user's coding requirements and to provide fast execution and good accuracy for a large class of electromagnetic problems involving various related Hankel transform sets with multiple arguments. Special cases of Hankel transforms of double-order and double-argument are discussed, where use of HYBFHT is shown to be advantageous for oscillatory kernal functions. -Author

  18. Fast Algorithms for Model-Based Diagnosis

    NASA Technical Reports Server (NTRS)

    Fijany, Amir; Barrett, Anthony; Vatan, Farrokh; Mackey, Ryan

    2005-01-01

    Two improved new methods for automated diagnosis of complex engineering systems involve the use of novel algorithms that are more efficient than prior algorithms used for the same purpose. Both the recently developed algorithms and the prior algorithms in question are instances of model-based diagnosis, which is based on exploring the logical inconsistency between an observation and a description of a system to be diagnosed. As engineering systems grow more complex and increasingly autonomous in their functions, the need for automated diagnosis increases concomitantly. In model-based diagnosis, the function of each component and the interconnections among all the components of the system to be diagnosed (for example, see figure) are represented as a logical system, called the system description (SD). Hence, the expected behavior of the system is the set of logical consequences of the SD. Faulty components lead to inconsistency between the observed behaviors of the system and the SD. The task of finding the faulty components (diagnosis) reduces to finding the components, the abnormalities of which could explain all the inconsistencies. Of course, the meaningful solution should be a minimal set of faulty components (called a minimal diagnosis), because the trivial solution, in which all components are assumed to be faulty, always explains all inconsistencies. Although the prior algorithms in question implement powerful methods of diagnosis, they are not practical because they essentially require exhaustive searches among all possible combinations of faulty components and therefore entail the amounts of computation that grow exponentially with the number of components of the system.

  19. A Midsize Tokamak As Fast Track To Burning Plasmas

    SciTech Connect

    E. Mazzucato

    2010-07-14

    This paper presents a midsize tokamak as a fast track to the investigation of burning plasmas. It is shown that it could reach large values of energy gain (≥10) with only a modest improvement in confinement over the scaling that was used for designing the International Thermonuclear Experimental Reactor (ITER). This could be achieved by operating in a low plasma recycling regime that experiments indicate can lead to improved plasma confinement. The possibility of reaching the necessary conditions of low recycling using a more efficient magnetic divertor than those of present tokamaks is discussed.

  20. Short Hospital Stay after Laparoscopic Colorectal Surgery without Fast Track

    PubMed Central

    Burgdorf, Stefan K.; Rosenberg, Jacob

    2012-01-01

    Purpose. Short hospital stay and equal or reduced complication rates have been demonstrated after fast track open colonic surgery. However, fast track principles of perioperative care can be difficult to implement and often require increased nursing staff because of more concentrated nursing tasks during the shorter hospital stay. Specific data on nursing requirements after laparoscopic surgery are lacking. The purpose of the study was to evaluate the effect of operative technique (open versus laparoscopic operation), but without changing nurse staffing or principles for peri- or postoperative care, that is, without implementing fast track principles, on length of stay after colorectal resection for cancer. Methods. Records of all patients operated for colorectal cancer from November 2004 to December 2008 in our department were reviewed. No specific patients were selected for laparoscopic repair, which was solely dependent on the presence of two specific surgeons at the same time. Thus, the patients were not selected for laparoscopic repair based on patient-related factors, but only on the simultaneous presence of two specific surgeons on the day of the operation. Results. Of a total of 540 included patients, 213 (39%) were operated by a laparoscopic approach. The median hospital stay for patients with a primary anastomosis was significantly shorter after laparoscopic than after conventional open surgery (5 versus 8 days, P < 0.001) while there was no difference in patients receiving a stoma (10 versus 10 days, ns), with no changes in the perioperative care regimens. Furthermore there were significant lower blood loss (50 versus 200 mL, P < 0.001) and lower complication rate (21% versus 32%, P = 0.006) in the laparoscopic group. Conclusion. Implementing laparoscopic colorectal surgery in our department resulted in shorter hospital stay without using fast track principles for peri- and postoperative care in patients not receiving a stoma during the operation

  1. Fast algorithm for probabilistic bone edge detection (FAPBED)

    NASA Astrophysics Data System (ADS)

    Scepanovic, Danilo; Kirshtein, Joshua; Jain, Ameet K.; Taylor, Russell H.

    2005-04-01

    The registration of preoperative CT to intra-operative reality systems is a crucial step in Computer Assisted Orthopedic Surgery (CAOS). The intra-operative sensors include 3D digitizers, fiducials, X-rays and Ultrasound (US). FAPBED is designed to process CT volumes for registration to tracked US data. Tracked US is advantageous because it is real time, noninvasive, and non-ionizing, but it is also known to have inherent inaccuracies which create the need to develop a framework that is robust to various uncertainties, and can be useful in US-CT registration. Furthermore, conventional registration methods depend on accurate and absolute segmentation. Our proposed probabilistic framework addresses the segmentation-registration duality, wherein exact segmentation is not a prerequisite to achieve accurate registration. In this paper, we develop a method for fast and automatic probabilistic bone surface (edge) detection in CT images. Various features that influence the likelihood of the surface at each spatial coordinate are combined using a simple probabilistic framework, which strikes a fair balance between a high-level understanding of features in an image and the low-level number crunching of standard image processing techniques. The algorithm evaluates different features for detecting the probability of a bone surface at each voxel, and compounds the results of these methods to yield a final, low-noise, probability map of bone surfaces in the volume. Such a probability map can then be used in conjunction with a similar map from tracked intra-operative US to achieve accurate registration. Eight sample pelvic CT scans were used to extract feature parameters and validate the final probability maps. An un-optimized fully automatic Matlab code runs in five minutes per CT volume on average, and was validated by comparison against hand-segmented gold standards. The mean probability assigned to nonzero surface points was 0.8, while nonzero non-surface points had a mean

  2. Fast-neutron spectroscopy studies using induced-proton tracks in PADC track detectors

    NASA Astrophysics Data System (ADS)

    El-Sersy, A. R.; Eman, S. A.

    2010-06-01

    In this work, a simple and adequate method for fast-neutron spectroscopy is proposed. This method was performed by free-in-air fast-neutron irradiation of CR-39 Nuclear Track Detectors (NTD) using an Am-Be source. Detectors were then chemically etched to remove few layers up to a thickness of 6.25 μm. By using an automatic image analyzer system for studying the registration of the induced-proton tracks in the NTD, the obtained data were analyzed via two tracks shapes. In the first one, the elliptical tracks were eliminated from the calculation and only the circular ones were considered in developing the response function. In the second method all registered tracks were considered and the corresponding response function was obtained. The rate of energy loss of the protons as a function of V[(d E/d X) - V] was calculated using the Monte Carlo simulation. The induced-proton energy was extracted from the corresponding d E/d X in NTD using a computer program based on the Bethe-Bloch function. The energy of the incident particles was up to few hundred MeV/nucleon. The energy of the interacting neutrons was then estimated by means of the extracted induced-proton energies and the scattering angle. It was found that the present resulting energy distribution of the fast-neutron spectrum from the Am-Be source was similar to that given in the literature where an average neutron energy of 4.6MeV was obtained.

  3. A fast SEQUEST cross correlation algorithm.

    PubMed

    Eng, Jimmy K; Fischer, Bernd; Grossmann, Jonas; Maccoss, Michael J

    2008-10-01

    The SEQUEST program was the first and remains one of the most widely used tools for assigning a peptide sequence within a database to a tandem mass spectrum. The cross correlation score is the primary score function implemented within SEQUEST and it is this score that makes the tool particularly sensitive. Unfortunately, this score is computationally expensive to calculate, and thus, to make the score manageable, SEQUEST uses a less sensitive but fast preliminary score and restricts the cross correlation to just the top 500 peptides returned by the preliminary score. Classically, the cross correlation score has been calculated using Fast Fourier Transforms (FFT) to generate the full correlation function. We describe an alternate method of calculating the cross correlation score that does not require FFTs and can be computed efficiently in a fraction of the time. The fast calculation allows all candidate peptides to be scored by the cross correlation function, potentially mitigating the need for the preliminary score, and enables an E-value significance calculation based on the cross correlation score distribution calculated on all candidate peptide sequences obtained from a sequence database. PMID:18774840

  4. Infrared image guidance for ground vehicle based on fast wavelet image focusing and tracking

    NASA Astrophysics Data System (ADS)

    Akiyama, Akira; Kobayashi, Nobuaki; Mutoh, Eiichiro; Kumagai, Hideo; Yamada, Hirofumi; Ishii, Hiromitsu

    2009-08-01

    We studied the infrared image guidance for ground vehicle based on the fast wavelet image focusing and tracking. Here we uses the image of the uncooled infrared imager mounted on the two axis gimbal system and the developed new auto focusing algorithm on the Daubechies wavelet transform. The developed new focusing algorithm on the Daubechies wavelet transform processes the result of the high pass filter effect to meet the direct detection of the objects. This new focusing gives us the distance information of the outside world smoothly, and the information of the gimbal system gives us the direction of objects in the outside world to match the sense of the spherical coordinate system. We installed this system on the hand made electric ground vehicle platform powered by 24VDC battery. The electric vehicle equips the rotary encoder units and the inertia rate sensor units to make the correct navigation process. The image tracking also uses the developed newt wavelet focusing within several image processing. The size of the hand made electric ground vehicle platform is about 1m long, 0.75m wide, 1m high, and 50kg weight. We tested the infrared image guidance for ground vehicle based on the new wavelet image focusing and tracking using the electric vehicle indoor and outdoor. The test shows the good results by the developed infrared image guidance for ground vehicle based on the new wavelet image focusing and tracking.

  5. Fast search algorithms for computational protein design.

    PubMed

    Traoré, Seydou; Roberts, Kyle E; Allouche, David; Donald, Bruce R; André, Isabelle; Schiex, Thomas; Barbe, Sophie

    2016-05-01

    One of the main challenges in computational protein design (CPD) is the huge size of the protein sequence and conformational space that has to be computationally explored. Recently, we showed that state-of-the-art combinatorial optimization technologies based on Cost Function Network (CFN) processing allow speeding up provable rigid backbone protein design methods by several orders of magnitudes. Building up on this, we improved and injected CFN technology into the well-established CPD package Osprey to allow all Osprey CPD algorithms to benefit from associated speedups. Because Osprey fundamentally relies on the ability of A* to produce conformations in increasing order of energy, we defined new A* strategies combining CFN lower bounds, with new side-chain positioning-based branching scheme. Beyond the speedups obtained in the new A*-CFN combination, this novel branching scheme enables a much faster enumeration of suboptimal sequences, far beyond what is reachable without it. Together with the immediate and important speedups provided by CFN technology, these developments directly benefit to all the algorithms that previously relied on the DEE/ A* combination inside Osprey* and make it possible to solve larger CPD problems with provable algorithms. PMID:26833706

  6. Two fast algorithms of image inpainting

    NASA Astrophysics Data System (ADS)

    He, Yuqing; Hou, Zhengxin; Wang, Chengyou

    2008-03-01

    Digital image inpainting is an interesting new research topic in multimedia computing and image processing since 2000. This talk covers the most recent contributions in digital image inpainting and image completion, as well as concepts in video inpainting. Image inpainting refers to reconstructing the corrupt regions where the data are all destroyed. A primary class of the technique is to build up a Partial Differential Equation (PDE), consider it as a boundary problem, and solve it by some iterative method. The most representative and creative one of the inpainting algorithms is Bertalmio-Sapiro-Caselles-Bellester (BSCB) model. After summarizes the development of image inpainting technique, this paper points the research at the improvement on BSCB model, and proposes two algorithms to solve the two drawbacks of this model. The first is selective adaptive interpolation which develops the traditional adaptive interpolation algorithm by introducing a priority value. Besides much faster than BSCB model, it can improve the inpainting effects. The second takes selective adaptive interpolation as a preprocessing step, reduces the operation time and improves the inpainting quality further.

  7. Quantization Effects and Stabilization of the Fast-Kalman Algorithm

    NASA Astrophysics Data System (ADS)

    Papaodysseus, Constantin; Alexiou, Constantin; Roussopoulos, George; Panagopoulos, Athanasios

    2001-12-01

    The exact and actual cause of the failure of the fast-Kalman algorithm due to the generation and propagation of finite-precision or quantization error is presented. It is demonstrated that out of all the formulas that constitute this fast Recursive Least Squares (RLS) scheme only three generate an amount of finite-precision error that consistently propagates in the subsequent iterations and eventually makes the algorithm fail after a certain number of recursions. Moreover, it is shown that there is a very limited number of specific formulas that transmit the generated finite-precision error, while there is another class of formulas that lift or "relax" this error. In addition, a number of general propositions is presented that allow for the calculation of the exact number of erroneous digits with which the various quantities of the fast-Kalman scheme are computed, including the filter coefficients. On the basis of the previous analysis a method of stabilization of the fast-Kalman algorithm is developed and is presented here, a method that allows for the fast-Kalman algorithm to follow very difficult signals such as music, speech, environmental noise, and other nonstationary ones. Finally, a general methodology is pointed out, that allows for the development of new algorithms which, intrinsically, suffer far less of finite-precision problems.

  8. A fast algorithm for numerical solutions to Fortet's equation

    NASA Astrophysics Data System (ADS)

    Brumen, Gorazd

    2008-10-01

    A fast algorithm for computation of default times of multiple firms in a structural model is presented. The algorithm uses a multivariate extension of the Fortet's equation and the structure of Toeplitz matrices to significantly improve the computation time. In a financial market consisting of M[not double greater-than sign]1 firms and N discretization points in every dimension the algorithm uses O(nlogn·M·M!·NM(M-1)/2) operations, where n is the number of discretization points in the time domain. The algorithm is applied to firm survival probability computation and zero coupon bond pricing.

  9. X-33 Environmental Impact Statement: A Fast Track Approach

    NASA Technical Reports Server (NTRS)

    McCaleb, Rebecca C.; Holland, Donna L.

    1998-01-01

    NASA is required by the National Environmental Policy Act (NEPA) to prepare an appropriate level environmental analysis for its major projects. Development of the X-33 Technology Demonstrator and its associated flight test program required an environmental impact statement (EIS) under the NEPA. The EIS process is consists of four parts: the "Notice of Intent" to prepare an EIS and scoping; the draft EIS which is distributed for review and comment; the final ETS; and the "Record of Decision." Completion of this process normally takes from 2 - 3 years, depending on the complexity of the proposed action. Many of the agency's newest fast track, technology demonstration programs require NEPA documentation, but cannot sustain the lengthy time requirement between program concept development to implementation. Marshall Space Flight Center, in cooperation with Kennedy Space Center, accomplished the NEPA process for the X-33 Program in 13 months from Notice of Intent to Record of Decision. In addition, the environmental team implemented an extensive public involvement process, conducting a total of 23 public meetings for scoping and draft EIS comment along with numerous informal meetings with public officials, civic organizations, and Native American Indians. This paper will discuss the fast track approach used to successfully accomplish the NEPA process for X-33 on time.

  10. "Eztrack": A single-vehicle deterministic tracking algorithm

    SciTech Connect

    Carrano, C J

    2007-12-20

    A variety of surveillance operations require the ability to track vehicles over a long period of time using sequences of images taken from a camera mounted on an airborne or similar platform. In order to be able to see and track a vehicle for any length of time, either a persistent surveillance imager is needed that can image wide fields of view over a long time-span or a highly maneuverable smaller field-of-view imager is needed that can follow the vehicle of interest. The algorithm described here was designed for the persistence surveillance case. In turns out that most vehicle tracking algorithms described in the literature[1,2,3,4] are designed for higher frame rates (> 5 FPS) and relatively short ground sampling distances (GSD) and resolutions ({approx} few cm to a couple tens of cm). But for our datasets, we are restricted to lower resolutions and GSD's ({ge}0.5 m) and limited frame-rates ({le}2.0 Hz). As a consequence, we designed our own simple approach in IDL which is a deterministic, motion-guided object tracker. The object tracking relies both on object features and path dynamics. The algorithm certainly has room for future improvements, but we have found it to be a useful tool in evaluating effects of frame-rate, resolution/GSD, and spectral content (eg. grayscale vs. color imaging ). A block diagram of the tracking approach is given in Figure 1. We describe each of the blocks of the diagram in the upcoming sections.

  11. Fast Track Finding in the ILC's Silicon Detecgor, SiD01

    SciTech Connect

    Baker, David E.; /Carnegie Mellon U.

    2007-11-07

    A fast track finder is presented which, unlike its more efficient, more computationally costly O(n3) time counterparts, tracks particles in O(n) time (for n being the number of hits). Developed as a tool for processing data from the ILC's proposed SiD detector, development of this fast track finder began with that proposed by Pablo Yepes in 1996 and adjusted to accommodate the changes in geometry of the SiD detector. First, space within the detector is voxellated, with hits assigned to voxels according to their r, {phi}, and {eta} coordinates. A hit on the outermost layer is selected, and a 'sample space' is built from the hits in the selected hit's surrounding voxels. The hit in the sample space with the smallest distance to the first is then selected, and the sample space recalculated for this hit. This process continues until the list of hits becomes large enough, at which point the helical circle in the x, y plane is conformally mapped to a line in the x', y' plane, and hits are chosen from the sample spaces of the previous fit by selecting the hits which fit a line to the previously selected points with the smallest {chi}{sup 2}. Track finding terminates when the innermost layer has been reached or no hit in the sample space fits those previously selected to an acceptable {chi}{sup 2}. Again, a hit on the outermost layer is selected and the process repeats until no assignable hits remain. The algorithm proved to be very efficient on artificial diagnostic events, such as one hundred muons scattered at momenta of 1 GeV/c to 10 GeV/c. Unfortunately, when tracking simulated events corresponding to actual physics, the track finder's efficiency decreased drastically (mostly due to signal noise), though future data cleaning programs could noticeably increase its efficiency on these events.

  12. Fast, Parallel and Secure Cryptography Algorithm Using Lorenz's Attractor

    NASA Astrophysics Data System (ADS)

    Marco, Anderson Gonçalves; Martinez, Alexandre Souto; Bruno, Odemir Martinez

    A novel cryptography method based on the Lorenz's attractor chaotic system is presented. The proposed algorithm is secure and fast, making it practical for general use. We introduce the chaotic operation mode, which provides an interaction among the password, message and a chaotic system. It ensures that the algorithm yields a secure codification, even if the nature of the chaotic system is known. The algorithm has been implemented in two versions: one sequential and slow and the other, parallel and fast. Our algorithm assures the integrity of the ciphertext (we know if it has been altered, which is not assured by traditional algorithms) and consequently its authenticity. Numerical experiments are presented, discussed and show the behavior of the method in terms of security and performance. The fast version of the algorithm has a performance comparable to AES, a popular cryptography program used commercially nowadays, but it is more secure, which makes it immediately suitable for general purpose cryptography applications. An internet page has been set up, which enables the readers to test the algorithm and also to try to break into the cipher.

  13. Some important observations on fast decoupled load flow algorithm

    SciTech Connect

    Nanda, J.; Kothari, D.P.; Srivastava, S.C.

    1987-05-01

    This letter brings out clearly for the first time the relative importance and weightage of some of the assumptions made by B. Scott and O. Alsac in their fast decoupled load flow (FDLF) algorithm on its convergence property. Results have been obtained for two sample IEEE test systems. The conclusions of this work are envisaged to be of immense practical relevance while developing a fast decoupled load flow program.

  14. Fast prediction algorithm for multiview video coding

    NASA Astrophysics Data System (ADS)

    Abdelazim, Abdelrahman; Mein, Stephen James; Varley, Martin Roy; Ait-Boudaoud, Djamel

    2013-03-01

    The H.264/multiview video coding (MVC) standard has been developed to enable efficient coding for three-dimensional and multiple viewpoint video sequences. The inter-view statistical dependencies are utilized and an inter-view prediction is employed to provide more efficient coding; however, this increases the overall encoding complexity. Motion homogeneity is exploited here to selectively enable inter-view prediction, and to reduce complexity in the motion estimation (ME) and the mode selection processes. This has been accomplished by defining situations that relate macro-blocks' motion characteristics to the mode selection and the inter-view prediction processes. When comparing the proposed algorithm to the H.264/MVC reference software and other recent work, the experimental results demonstrate a significant reduction in ME time while maintaining similar rate-distortion performance.

  15. Computer program for fast Karhunen Loeve transform algorithm

    NASA Technical Reports Server (NTRS)

    Jain, A. K.

    1976-01-01

    The fast KL transform algorithm was applied for data compression of a set of four ERTS multispectral images and its performance was compared with other techniques previously studied on the same image data. The performance criteria used here are mean square error and signal to noise ratio. The results obtained show a superior performance of the fast KL transform coding algorithm on the data set used with respect to the above stated perfomance criteria. A summary of the results is given in Chapter I and details of comparisons and discussion on conclusions are given in Chapter IV.

  16. Fast sampling algorithm for Lie-Trotter products.

    PubMed

    Predescu, Cristian

    2005-04-01

    A fast algorithm for path sampling in path-integral Monte Carlo simulations is proposed. The algorithm utilizes the Lévy-Ciesielski implementation of Lie-Trotter products to achieve a mathematically proven computational cost of n log2(n) with the number of time slices n, despite the fact that each path variable is updated separately, for reasons of optimality. In this respect, we demonstrate that updating a group of random variables simultaneously results in loss of efficiency. PMID:15903719

  17. Fast algorithm for integrating inconsistent gradient fields.

    PubMed

    Rivera, M; Marroquin, J L; Servin, M; Rodriguez-Vera, R

    1997-11-10

    A discrete Fourier transform (DFT) based algorithm for solving a quadratic cost functional is proposed; this regularized functional allows one to obtain a consistent gradient field from an inconsistent one. The calculated consistent gradient may then be integrated by use of simple methods. The technique is presented in the context of the phase-unwrapping problem; however, it may be applied to other problems, such as shapes from shading (a robot-vision technique) when inconsistent gradient fields with irregular domains are obtained. The regularized functional introduced here has advantages over existing techniques; in particular, it is able to manage complex irregular domains and to interpolate over regions with invalid data without any smoothness assumptions over the rest of the lattice, so that the estimation error is reduced. Furthermore, there are no free parameters to adjust. The DFT is used to compute a preconditioner because there is highly efficient hardware to perform the calculations and also because it may be computed by optical means. PMID:18264380

  18. A fast image matching algorithm based on key points

    NASA Astrophysics Data System (ADS)

    Wang, Huilin; Wang, Ying; An, Ru; Yan, Peng

    2014-05-01

    Image matching is a very important technique in image processing. It has been widely used for object recognition and tracking, image retrieval, three-dimensional vision, change detection, aircraft position estimation, and multi-image registration. Based on the requirements of matching algorithm for craft navigation, such as speed, accuracy and adaptability, a fast key point image matching method is investigated and developed. The main research tasks includes: (1) Developing an improved celerity key point detection approach using self-adapting threshold of Features from Accelerated Segment Test (FAST). A method of calculating self-adapting threshold was introduced for images with different contrast. Hessian matrix was adopted to eliminate insecure edge points in order to obtain key points with higher stability. This approach in detecting key points has characteristics of small amount of computation, high positioning accuracy and strong anti-noise ability; (2) PCA-SIFT is utilized to describe key point. 128 dimensional vector are formed based on the SIFT method for the key points extracted. A low dimensional feature space was established by eigenvectors of all the key points, and each eigenvector was projected onto the feature space to form a low dimensional eigenvector. These key points were re-described by dimension-reduced eigenvectors. After reducing the dimension by the PCA, the descriptor was reduced to 20 dimensions from the original 128. This method can reduce dimensions of searching approximately near neighbors thereby increasing overall speed; (3) Distance ratio between the nearest neighbour and second nearest neighbour searching is regarded as the measurement criterion for initial matching points from which the original point pairs matched are obtained. Based on the analysis of the common methods (e.g. RANSAC (random sample consensus) and Hough transform cluster) used for elimination false matching point pairs, a heuristic local geometric restriction

  19. Fast image matching algorithm based on projection characteristics

    NASA Astrophysics Data System (ADS)

    Zhou, Lijuan; Yue, Xiaobo; Zhou, Lijun

    2011-06-01

    Based on analyzing the traditional template matching algorithm, this paper identified the key factors restricting the speed of matching and put forward a brand new fast matching algorithm based on projection. Projecting the grayscale image, this algorithm converts the two-dimensional information of the image into one-dimensional one, and then matches and identifies through one-dimensional correlation, meanwhile, because of normalization has been done, when the image brightness or signal amplitude increasing in proportion, it could also perform correct matching. Experimental results show that the projection characteristics based image registration method proposed in this article could greatly improve the matching speed, which ensuring the matching accuracy as well.

  20. A fast directional algorithm for high-frequency electromagnetic scattering

    SciTech Connect

    Tsuji, Paul; Ying Lexing

    2011-06-20

    This paper is concerned with the fast solution of high-frequency electromagnetic scattering problems using the boundary integral formulation. We extend the O(N log N) directional multilevel algorithm previously proposed for the acoustic scattering case to the vector electromagnetic case. We also detail how to incorporate the curl operator of the magnetic field integral equation into the algorithm. When combined with a standard iterative method, this results in an almost linear complexity solver for the combined field integral equations. In addition, the butterfly algorithm is utilized to compute the far field pattern and radar cross section with O(N log N) complexity.

  1. Fast frequency acquisition via adaptive least squares algorithm

    NASA Technical Reports Server (NTRS)

    Kumar, R.

    1986-01-01

    A new least squares algorithm is proposed and investigated for fast frequency and phase acquisition of sinusoids in the presence of noise. This algorithm is a special case of more general, adaptive parameter-estimation techniques. The advantages of the algorithms are their conceptual simplicity, flexibility and applicability to general situations. For example, the frequency to be acquired can be time varying, and the noise can be nonGaussian, nonstationary and colored. As the proposed algorithm can be made recursive in the number of observations, it is not necessary to have a priori knowledge of the received signal-to-noise ratio or to specify the measurement time. This would be required for batch processing techniques, such as the fast Fourier transform (FFT). The proposed algorithm improves the frequency estimate on a recursive basis as more and more observations are obtained. When the algorithm is applied in real time, it has the extra advantage that the observations need not be stored. The algorithm also yields a real time confidence measure as to the accuracy of the estimator.

  2. MATLAB tensor classes for fast algorithm prototyping : source code.

    SciTech Connect

    Bader, Brett William; Kolda, Tamara Gibson

    2004-10-01

    We present the source code for three MATLAB classes for manipulating tensors in order to allow fast algorithm prototyping. A tensor is a multidimensional or Nway array. This is a supplementary report; details on using this code are provided separately in SAND-XXXX.

  3. Validation of a track repeating algorithm for intensity modulated proton therapy: clinical cases study

    NASA Astrophysics Data System (ADS)

    Yepes, Pablo P.; Eley, John G.; Liu, Amy; Mirkovic, Dragan; Randeniya, Sharmalee; Titt, Uwe; Mohan, Radhe

    2016-04-01

    Monte Carlo (MC) methods are acknowledged as the most accurate technique to calculate dose distributions. However, due its lengthy calculation times, they are difficult to utilize in the clinic or for large retrospective studies. Track-repeating algorithms, based on MC-generated particle track data in water, accelerate dose calculations substantially, while essentially preserving the accuracy of MC. In this study, we present the validation of an efficient dose calculation algorithm for intensity modulated proton therapy, the fast dose calculator (FDC), based on a track-repeating technique. We validated the FDC algorithm for 23 patients, which included 7 brain, 6 head-and-neck, 5 lung, 1 spine, 1 pelvis and 3 prostate cases. For validation, we compared FDC-generated dose distributions with those from a full-fledged Monte Carlo based on GEANT4 (G4). We compared dose-volume-histograms, 3D-gamma-indices and analyzed a series of dosimetric indices. More than 99% of the voxels in the voxelized phantoms describing the patients have a gamma-index smaller than unity for the 2%/2 mm criteria. In addition the difference relative to the prescribed dose between the dosimetric indices calculated with FDC and G4 is less than 1%. FDC reduces the calculation times from 5 ms per proton to around 5 μs.

  4. Validation of a track repeating algorithm for intensity modulated proton therapy: clinical cases study.

    PubMed

    Yepes, Pablo P; Eley, John G; Liu, Amy; Mirkovic, Dragan; Randeniya, Sharmalee; Titt, Uwe; Mohan, Radhe

    2016-04-01

    Monte Carlo (MC) methods are acknowledged as the most accurate technique to calculate dose distributions. However, due its lengthy calculation times, they are difficult to utilize in the clinic or for large retrospective studies. Track-repeating algorithms, based on MC-generated particle track data in water, accelerate dose calculations substantially, while essentially preserving the accuracy of MC. In this study, we present the validation of an efficient dose calculation algorithm for intensity modulated proton therapy, the fast dose calculator (FDC), based on a track-repeating technique. We validated the FDC algorithm for 23 patients, which included 7 brain, 6 head-and-neck, 5 lung, 1 spine, 1 pelvis and 3 prostate cases. For validation, we compared FDC-generated dose distributions with those from a full-fledged Monte Carlo based on GEANT4 (G4). We compared dose-volume-histograms, 3D-gamma-indices and analyzed a series of dosimetric indices. More than 99% of the voxels in the voxelized phantoms describing the patients have a gamma-index smaller than unity for the 2%/2 mm criteria. In addition the difference relative to the prescribed dose between the dosimetric indices calculated with FDC and G4 is less than 1%. FDC reduces the calculation times from 5 ms per proton to around 5 μs. PMID:26961764

  5. A fast algorithm for sparse matrix computations related to inversion

    NASA Astrophysics Data System (ADS)

    Li, S.; Wu, W.; Darve, E.

    2013-06-01

    We have developed a fast algorithm for computing certain entries of the inverse of a sparse matrix. Such computations are critical to many applications, such as the calculation of non-equilibrium Green's functions Gr and G< for nano-devices. The FIND (Fast Inverse using Nested Dissection) algorithm is optimal in the big-O sense. However, in practice, FIND suffers from two problems due to the width-2 separators used by its partitioning scheme. One problem is the presence of a large constant factor in the computational cost of FIND. The other problem is that the partitioning scheme used by FIND is incompatible with most existing partitioning methods and libraries for nested dissection, which all use width-1 separators. Our new algorithm resolves these problems by thoroughly decomposing the computation process such that width-1 separators can be used, resulting in a significant speedup over FIND for realistic devices — up to twelve-fold in simulation. The new algorithm also has the added advantage that desired off-diagonal entries can be computed for free. Consequently, our algorithm is faster than the current state-of-the-art recursive methods for meshes of any size. Furthermore, the framework used in the analysis of our algorithm is the first attempt to explicitly apply the widely-used relationship between mesh nodes and matrix computations to the problem of multiple eliminations with reuse of intermediate results. This framework makes our algorithm easier to generalize, and also easier to compare against other methods related to elimination trees. Finally, our accuracy analysis shows that the algorithms that require back-substitution are subject to significant extra round-off errors, which become extremely large even for some well-conditioned matrices or matrices with only moderately large condition numbers. When compared to these back-substitution algorithms, our algorithm is generally a few orders of magnitude more accurate, and our produced round-off errors

  6. Fast parallel algorithm for slicing STL based on pipeline

    NASA Astrophysics Data System (ADS)

    Ma, Xulong; Lin, Feng; Yao, Bo

    2016-04-01

    In Additive Manufacturing field, the current researches of data processing mainly focus on a slicing process of large STL files or complicated CAD models. To improve the efficiency and reduce the slicing time, a parallel algorithm has great advantages. However, traditional algorithms can't make full use of multi-core CPU hardware resources. In the paper, a fast parallel algorithm is presented to speed up data processing. A pipeline mode is adopted to design the parallel algorithm. And the complexity of the pipeline algorithm is analyzed theoretically. To evaluate the performance of the new algorithm, effects of threads number and layers number are investigated by a serial of experiments. The experimental results show that the threads number and layers number are two remarkable factors to the speedup ratio. The tendency of speedup versus threads number reveals a positive relationship which greatly agrees with the Amdahl's law, and the tendency of speedup versus layers number also keeps a positive relationship agreeing with Gustafson's law. The new algorithm uses topological information to compute contours with a parallel method of speedup. Another parallel algorithm based on data parallel is used in experiments to show that pipeline parallel mode is more efficient. A case study at last shows a suspending performance of the new parallel algorithm. Compared with the serial slicing algorithm, the new pipeline parallel algorithm can make full use of the multi-core CPU hardware, accelerate the slicing process, and compared with the data parallel slicing algorithm, the new slicing algorithm in this paper adopts a pipeline parallel model, and a much higher speedup ratio and efficiency is achieved.

  7. Fast parallel algorithm for slicing STL based on pipeline

    NASA Astrophysics Data System (ADS)

    Ma, Xulong; Lin, Feng; Yao, Bo

    2016-05-01

    In Additive Manufacturing field, the current researches of data processing mainly focus on a slicing process of large STL files or complicated CAD models. To improve the efficiency and reduce the slicing time, a parallel algorithm has great advantages. However, traditional algorithms can't make full use of multi-core CPU hardware resources. In the paper, a fast parallel algorithm is presented to speed up data processing. A pipeline mode is adopted to design the parallel algorithm. And the complexity of the pipeline algorithm is analyzed theoretically. To evaluate the performance of the new algorithm, effects of threads number and layers number are investigated by a serial of experiments. The experimental results show that the threads number and layers number are two remarkable factors to the speedup ratio. The tendency of speedup versus threads number reveals a positive relationship which greatly agrees with the Amdahl's law, and the tendency of speedup versus layers number also keeps a positive relationship agreeing with Gustafson's law. The new algorithm uses topological information to compute contours with a parallel method of speedup. Another parallel algorithm based on data parallel is used in experiments to show that pipeline parallel mode is more efficient. A case study at last shows a suspending performance of the new parallel algorithm. Compared with the serial slicing algorithm, the new pipeline parallel algorithm can make full use of the multi-core CPU hardware, accelerate the slicing process, and compared with the data parallel slicing algorithm, the new slicing algorithm in this paper adopts a pipeline parallel model, and a much higher speedup ratio and efficiency is achieved.

  8. Particle filter-based track before detect algorithms

    NASA Astrophysics Data System (ADS)

    Boers, Yvo; Driessen, Hans

    2003-12-01

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

  9. Particle filter-based track before detect algorithms

    NASA Astrophysics Data System (ADS)

    Boers, Yvo; Driessen, Hans

    2004-01-01

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

  10. Performance analysis of bearings-only tracking algorithm

    NASA Astrophysics Data System (ADS)

    van Huyssteen, David; Farooq, Mohamad

    1998-07-01

    A number of 'bearing-only' target motion analysis algorithms have appeared in the literature over the years, all suited to track an object based solely on noisy measurements of its angular position. In their paper 'Utilization of Modified Polar (MP) Coordinates for Bearings-Only Tracking' Aidala and Hammel advocate a filter in which the observable and unobservable states are naturally decoupled. While the MP filter has certain advantages over Cartesian and pseudolinear extended Kalman filters, it does not escape the requirement for the observer to steer an optimum maneuvering course to guarantee acceptable performance. This paper demonstrates by simulation the consequence if the observer deviates from this profile, even if it is sufficient to produce full state observability.

  11. A generic sun-tracking algorithm for on-axis solar collector in mobile platforms

    NASA Astrophysics Data System (ADS)

    Lai, An-Chow; Chong, Kok-Keong; Lim, Boon-Han; Ho, Ming-Cheng; Yap, See-Hao; Heng, Chun-Kit; Lee, Jer-Vui; King, Yeong-Jin

    2015-04-01

    This paper proposes a novel dynamic sun-tracking algorithm which allows accurate tracking of the sun for both non-concentrated and concentrated photovoltaic systems located on mobile platforms to maximize solar energy extraction. The proposed algorithm takes not only the date, time, and geographical information, but also the dynamic changes of coordinates of the mobile platforms into account to calculate the sun position angle relative to ideal azimuth-elevation axes in real time using general sun-tracking formulas derived by Chong and Wong. The algorithm acquires data from open-loop sensors, i.e. global position system (GPS) and digital compass, which are readily available in many off-the-shelf portable gadgets, such as smart phone, to instantly capture the dynamic changes of coordinates of mobile platforms. Our experiments found that a highly accurate GPS is not necessary as the coordinate changes of practical mobile platforms are not fast enough to produce significant differences in the calculation of the incident angle. On the contrary, it is critical to accurately identify the quadrant and angle where the mobile platforms are moving toward in real time, which can be resolved by using digital compass. In our implementation, a noise filtering mechanism is found necessary to remove unexpected spikes in the readings of the digital compass to ensure stability in motor actuations and effectiveness in continuous tracking. Filtering mechanisms being studied include simple moving average and linear regression; the results showed that a compound function of simple moving average and linear regression produces a better outcome. Meanwhile, we found that a sampling interval is useful to avoid excessive motor actuations and power consumption while not sacrificing the accuracy of sun-tracking.

  12. The effect of a 'fast-track' unit on the performance of a cardiothoracic department.

    PubMed Central

    Hadjinikolaou, L.; Cohen, A.; Glenville, B.; Stanbridge, R. D.

    2000-01-01

    OBJECTIVE: The objective of this study was to describe the impact of a 'fast-track' unit, combined with a computerised system for information collection and analysis, on the clinical practice and finance of a cardiothoracic department over the first 12 month period of its application. METHODS: Within 12 months, starting December 1996, 642 major cardiothoracic cases were performed at the Cardiothoracic Department, St Mary's Hospital, London, after the establishment of a 3-bed 'fast-track' unit, which was supported by a computerised system for admission planning and a pre-admission clinic. The main outcome measures were operating numbers, financial income, patient recovery and operative mortality. RESULTS: The 'fast-track' unit resulted in an increase of the operating numbers (11.3% increase in major cardiac cases) and income (38%), as compared with the year before. Some 525 patients out of 642 (81.8%) were scheduled for the 'fast-track' unit and 492 (93.7%) were successfully 'fast-tracked'. Coronary artery bypass grafting operations had the lowest 'fast-track' failure and mortality rates. Re-do operations and complex coronary procedures presented a high 'fast-track' failure rate of approximately 20-25%. Low cardiac output, postoperative bleeding and respiratory problems were the most frequent causes for 'fast-track' failure. CONCLUSIONS: The development of a 'fast-track' unit, supported by a computerised system for information collection and analysis and a pre-admission clinic, has resulted in a substantial improvement of operating numbers and financial income, without adversely affecting the clinical results. This task demanded close collaboration between a dedicated list manager and a designated member of the medical team. Patient selection with appropriate 'fast-track,' criteria may improve further the efficiency of 'fast-track' units in the future. PMID:10700770

  13. Tracking algorithms using log-polar mapped image coordinates

    NASA Technical Reports Server (NTRS)

    Weiman, Carl F. R.; Juday, Richard D.

    1990-01-01

    The use of log-polar image sampling coordinates rather than conventional Cartesian coordinates offers a number of advantages for visual tracking and docking of space vehicles. Pixel count is reduced without decreasing the field of view, with commensurate reduction in peripheral resolution. Smaller memory requirements and reduced processing loads are the benefits in working environments where bulk and energy are at a premium. Rotational and zoom symmetries of log-polar coordinates accommodate range and orientation extremes without computational penalties. Separation of radial and rotational coordinates reduces the complexity of several target centering algorithms, described below.

  14. Fast pixel shifting phase unwrapping algorithm in quantitative interferometric microscopy

    NASA Astrophysics Data System (ADS)

    Xu, Mingfei; Shan, Yanke; Yan, Keding; Xue, Liang; Wang, Shouyu; Liu, Fei

    2014-11-01

    Quantitative interferometric microscopy is an important method for observing biological samples such as cells and tissues. In order to obtain continuous phase distribution of the sample from the interferogram, phase extracting and phase unwrapping are both needed in quantitative interferometric microscopy. Phase extracting includes fast Fourier transform method and Hilbert transform method, etc., almost all of them are rapid methods. However, traditional unwrapping methods such as least squares algorithm, minimum network flow method, etc. are time-consuming to locate the phase discontinuities which lead to low processing efficiency. Other proposed high-speed phase unwrapping methods always need at least two interferograms to recover final phase distributions which cannot realize real time processing. Therefore, high-speed phase unwrapping algorithm for single interferogram is required to improve the calculation efficiency. Here, we propose a fast phase unwrapping algorithm to realize high-speed quantitative interferometric microscopy, by shifting mod 2π wrapped phase map for one pixel, then multiplying the original phase map and the shifted one, then the phase discontinuities location can be easily determined. Both numerical simulation and experiments confirm that the algorithm features fast, precise and reliable.

  15. Improved genetic algorithm for fast path planning of USV

    NASA Astrophysics Data System (ADS)

    Cao, Lu

    2015-12-01

    Due to the complex constraints, more uncertain factors and critical real-time demand of path planning for USV(Unmanned Surface Vehicle), an approach of fast path planning based on voronoi diagram and improved Genetic Algorithm is proposed, which makes use of the principle of hierarchical path planning. First the voronoi diagram is utilized to generate the initial paths and then the optimal path is searched by using the improved Genetic Algorithm, which use multiprocessors parallel computing techniques to improve the traditional genetic algorithm. Simulation results verify that the optimal time is greatly reduced and path planning based on voronoi diagram and the improved Genetic Algorithm is more favorable in the real-time operation.

  16. The Empirical Mode Decomposition algorithm via Fast Fourier Transform

    NASA Astrophysics Data System (ADS)

    Myakinin, Oleg O.; Zakharov, Valery P.; Bratchenko, Ivan A.; Kornilin, Dmitry V.; Artemyev, Dmitry N.; Khramov, Alexander G.

    2014-09-01

    In this paper we consider a problem of implementing a fast algorithm for the Empirical Mode Decomposition (EMD). EMD is one of the newest methods for decomposition of non-linear and non-stationary signals. A basis of EMD is formed "on-the-fly", i.e. it depends from a distribution of the signal and not given a priori in contrast on cases Fourier Transform (FT) or Wavelet Transform (WT). The EMD requires interpolating of local extrema sets of signal to find upper and lower envelopes. The data interpolation on an irregular lattice is a very low-performance procedure. A classical description of EMD by Huang suggests doing this through splines, i.e. through solving of a system of equations. Existence of a fast algorithm is the main advantage of the FT. A simple description of an algorithm in terms of Fast Fourier Transform (FFT) is a standard practice to reduce operation's count. We offer a fast implementation of EMD (FEMD) through FFT and some other cost-efficient algorithms. Basic two-stage interpolation algorithm for EMD is composed of a Upscale procedure through FFT and Downscale procedure through a selection procedure for signal's points. First we consider the local maxima (or minima) set without reference to the axis OX, i.e. on a regular lattice. The Upscale through the FFT change the signal's length to the Least Common Multiple (LCM) value of all distances between neighboring extremes on the axis OX. If the LCM value is too large then it is necessary to limit local set of extrema. In this case it is an analog of the spline interpolation. A demo for FEMD in noise reduction task for OCT has been shown.

  17. Study of image matching algorithm and sub-pixel fitting algorithm in target tracking

    NASA Astrophysics Data System (ADS)

    Yang, Ming-dong; Jia, Jianjun; Qiang, Jia; Wang, Jian-yu

    2015-03-01

    Image correlation matching is a tracking method that searched a region most approximate to the target template based on the correlation measure between two images. Because there is no need to segment the image, and the computation of this method is little. Image correlation matching is a basic method of target tracking. This paper mainly studies the image matching algorithm of gray scale image, which precision is at sub-pixel level. The matching algorithm used in this paper is SAD (Sum of Absolute Difference) method. This method excels in real-time systems because of its low computation complexity. The SAD method is introduced firstly and the most frequently used sub-pixel fitting algorithms are introduced at the meantime. These fitting algorithms can't be used in real-time systems because they are too complex. However, target tracking often requires high real-time performance, we put forward a fitting algorithm named paraboloidal fitting algorithm based on the consideration above, this algorithm is simple and realized easily in real-time system. The result of this algorithm is compared with that of surface fitting algorithm through image matching simulation. By comparison, the precision difference between these two algorithms is little, it's less than 0.01pixel. In order to research the influence of target rotation on precision of image matching, the experiment of camera rotation was carried on. The detector used in the camera is a CMOS detector. It is fixed to an arc pendulum table, take pictures when the camera rotated different angles. Choose a subarea in the original picture as the template, and search the best matching spot using image matching algorithm mentioned above. The result shows that the matching error is bigger when the target rotation angle is larger. It's an approximate linear relation. Finally, the influence of noise on matching precision was researched. Gaussian noise and pepper and salt noise were added in the image respectively, and the image

  18. "Fast Track" and "Traditional Path" Coaches: Affordances, Agency and Social Capital

    ERIC Educational Resources Information Center

    Rynne, Steven

    2014-01-01

    A recent development in large-scale coach accreditation (certification) structures has been the "fast tracking" of former elite athletes. Former elite athletes are often exempted from entry-level qualifications and are generally granted access to fast track courses that are shortened versions of the accreditation courses undertaken by…

  19. National Diffusion Network's Evaluation of the Fast Track Music System 1992-93.

    ERIC Educational Resources Information Center

    Szymczuk, Michael

    This document reports on an evaluation project to determine the effectiveness of the Fast Track method of instrumental music instruction as applied to beginning band instruction. The Fast Track music system is unique because it simultaneously aids both visual and aural learning by using a book and cassette tape approach to instruction. Traditional…

  20. Financing Access and Participation in Primary Education: Is There a "Fast-Track" for Fragile States?

    ERIC Educational Resources Information Center

    Turrent, Victoria

    2011-01-01

    Despite moves to "fast-track" progress towards universal primary education, few fragile states have been able to access Fast Track Initiative (FTI) funding facilities. Weak systems and capacity have made these countries a high-risk proposition for donor investment. The absence of credible education sector plans has meant that the majority of…

  1. Fast-track for fast times: catching and keeping generation Y in the nursing workforce.

    PubMed

    Walker, Kim

    2007-04-01

    There is little doubt we find ourselves in challenging times as never before has there been such generational diversity in the nursing workforce. Currently, nurses from four distinct (and now well recognised and discussed) generational groups jostle for primacy of recognition and reward. Equally significant is the acute realisation that our ageing profession must find ways to sustain itself in the wake of huge attrition as the 'baby boomer' nurses start retiring over the next ten to fifteen years. These realities impel us to become ever more strategic in our thinking about how best to manage the workforce of the future. This paper presents two exciting and original innovations currently in train at one of Australia's leading Catholic health care providers: firstly, a new fast-track bachelor of nursing program for fee-paying domestic students. This is a collaborative venture between St Vincent's and Mater Health, Sydney (SV&MHS) and the University of Tasmania (UTas); as far as we know, it is unprecedented in Australia. As well, the two private facilities of SV&MHS, St Vincent's Private (SVPH) and the Mater Hospitals, have developed and implemented a unique 'accelerated progression pathway' (APP) to enable registered nurses with talent and ambition to fast track their career through a competency and merit based system of performance management and reward. Both these initiatives are aimed squarely at the gen Y demographic and provide potential to significantly augment our capacity to recruit and retain quality people well into the future. PMID:17563323

  2. Mean-shift tracking algorithm based on adaptive fusion of multi-feature

    NASA Astrophysics Data System (ADS)

    Yang, Kai; Xiao, Yanghui; Wang, Ende; Feng, Junhui

    2015-10-01

    The classic mean-shift tracking algorithm has achieved success in the field of computer vision because of its speediness and efficiency. However, classic mean-shift tracking algorithm would fail to track in some complicated conditions such as some parts of the target are occluded, little color difference between the target and background exists, or sudden change of illumination and so on. In order to solve the problems, an improved algorithm is proposed based on the mean-shift tracking algorithm and adaptive fusion of features. Color, edges and corners of the target are used to describe the target in the feature space, and a method for measuring the discrimination of various features is presented to make feature selection adaptive. Then the improved mean-shift tracking algorithm is introduced based on the fusion of various features. For the purpose of solving the problem that mean-shift tracking algorithm with the single color feature is vulnerable to sudden change of illumination, we eliminate the effects by the fusion of affine illumination model and color feature space which ensures the correctness and stability of target tracking in that condition. Using a group of videos to test the proposed algorithm, the results show that the tracking correctness and stability of this algorithm are better than the mean-shift tracking algorithm with single feature space. Furthermore the proposed algorithm is more robust than the classic algorithm in the conditions of occlusion, target similar with background or illumination change.

  3. Fast wavelet based algorithms for linear evolution equations

    NASA Technical Reports Server (NTRS)

    Engquist, Bjorn; Osher, Stanley; Zhong, Sifen

    1992-01-01

    A class was devised of fast wavelet based algorithms for linear evolution equations whose coefficients are time independent. The method draws on the work of Beylkin, Coifman, and Rokhlin which they applied to general Calderon-Zygmund type integral operators. A modification of their idea is applied to linear hyperbolic and parabolic equations, with spatially varying coefficients. A significant speedup over standard methods is obtained when applied to hyperbolic equations in one space dimension and parabolic equations in multidimensions.

  4. A fast track influenza virus vaccine produced in insect cells.

    PubMed

    Cox, Manon M J; Hashimoto, Yoshifumi

    2011-07-01

    The viral surface protein hemagglutinin (HA) has been recognized as a key antigen in the host response to influenza virus in both natural infection and vaccination because neutralizing antibodies directed against HA can mitigate or prevent infection. The baculovirus-insect cell system can be used for the production of recombinant HA molecules and is suitable for influenza vaccine production where annual adjustment of the vaccine is required. This expression system is generally considered safe with minimal potential for growth of human pathogens. Extensive characterization of this novel cell substrate has been performed, none of which has revealed the presence of adventitious agents. Multiple clinical studies have demonstrated that the vaccine is safe, well-tolerated and immunogenic. The baculovirus-insect cell system could, therefore, be used for the expedited production of a safe and efficacious influenza vaccine. As a result, this technology should provide a fast track worldwide solution for newly emerging influenza strains or pandemic preparedness within a few years. PMID:21784229

  5. Performance appraisal of estimation algorithms and application of estimation algorithms to target tracking

    NASA Astrophysics Data System (ADS)

    Zhao, Zhanlue

    This dissertation consists of two parts. The first part deals with the performance appraisal of estimation algorithms. The second part focuses on the application of estimation algorithms to target tracking. Performance appraisal is crucial for understanding, developing and comparing various estimation algorithms. In particular, with the evolvement of estimation theory and the increase of problem complexity, performance appraisal is getting more and more challenging for engineers to make comprehensive conclusions. However, the existing theoretical results are inadequate for practical reference. The first part of this dissertation is dedicated to performance measures which include local performance measures, global performance measures and model distortion measure. The second part focuses on application of the recursive best linear unbiased estimation (BLUE) or linear minimum mean square error (LIB-M-ISE) estimation to nonlinear measurement problem in target tracking. Kalman filter has been the dominant basis for dynamic state filtering for several decades. Beyond Kalman filter, a more fundamental basis for the recursive best linear unbiased filtering has been thoroughly investigated in a series of papers by my advisor Dr. X. Rong Li. Based on the so-called quasi-recursive best linear unbiased filtering technique, the constraints of the Kalman filter Linear-Gaussian assumptions can be relaxed such that a general linear filtering technique for nonlinear systems can be achieved. An approximate optimal BLUE filter is implemented for nonlinear measurements in target tracking which outperforms the existing method significantly in terms of accuracy, credibility and robustness.

  6. A parallel, volume-tracking algorithm for unstructured meshes

    SciTech Connect

    Mosso, S.J.; Swartz, B.K.; Kothe, D.B.; Ferrell, R.C.

    1996-10-01

    Many diverse areas of industry benefit from the use of volume of fluid methods to predict the movement of materials. Casting is a common method of part fabrication. The accurate prediction of the casting process is pivotal to industry. Mold design and casting is currently considered an art by industry. It typically involves many trial mold designs, and the rejection of defective parts is costly. Failure of cast parts, because residual stresses reduce the part`s strength, can be catastrophic. Cast parts should have precise geometric details that reduce or eliminate the need for machining after casting. Volume of fluid codes will help designers predict how the molten metal fills a mold and where ay trapped voids remain. Prediction of defects due to thermal contraction or expansion will eliminate defective, trial mold designs and speed the parts to market with fewer rejections. Increasing the predictability and therefore the accuracy of the casting process will reduce the art that is involved in mold design and parts casting. Here, recent enhancements to multidimensional volume-tracking algorithms are presented. Illustrations in two dimensions are given. The improvements include new, local algorithms for interface normal constructions and a new full remapping algorithm for time integration. These methods are used on structured and unstructured grids.

  7. A fast seed detection using local geometrical feature for automatic tracking of coronary arteries in CTA.

    PubMed

    Han, Dongjin; Doan, Nam-Thai; Shim, Hackjoon; Jeon, Byunghwan; Lee, Hyunna; Hong, Youngtaek; Chang, Hyuk-Jae

    2014-11-01

    We propose a fast seed detection for automatic tracking of coronary arteries in coronary computed tomographic angiography (CCTA). To detect vessel regions, Hessian-based filtering is combined with a new local geometric feature that is based on the similarity of the consecutive cross-sections perpendicular to the vessel direction. It is in turn founded on the prior knowledge that a vessel segment is shaped like a cylinder in axial slices. To improve computational efficiency, an axial slice, which contains part of three main coronary arteries, is selected and regions of interest (ROIs) are extracted in the slice. Only for the voxels belonging to the ROIs, the proposed geometric feature is calculated. With the seed points, which are the centroids of the detected vessel regions, and their vessel directions, vessel tracking method can be used for artery extraction. Here a particle filtering-based tracking algorithm is tested. Using 19 clinical CCTA datasets, it is demonstrated that the proposed method detects seed points and can be used for full automatic coronary artery extraction. ROC (receiver operating characteristic) curve analysis shows the advantages of the proposed method. PMID:25106730

  8. Fast algorithm of low power image reformation for OLED display

    NASA Astrophysics Data System (ADS)

    Lee, Myungwoo; Kim, Taewhan

    2014-04-01

    We propose a fast algorithm of low-power image reformation for organic light-emitting diode (OLED) display. The proposed algorithm scales the image histogram in a way to reduce power consumption in OLED display by remapping the gray levels of the pixels in the image based on the fast analysis of the histogram of the input image while maintaining contrast of the image. The key idea is that a large number of gray levels are never used in the images and these gray levels can be effectively exploited to reduce power consumption. On the other hand, to maintain the image contrast the gray level remapping is performed by taking into account the object size in the image to which each gray level is applied, that is, reforming little for the gray levels in the objects of large size. Through experiments with 24 Kodak images, it is shown that our proposed algorithm is able to reduce the power consumption by 10% even with 9% contrast enhancement. Our algorithm runs in a linear time so that it can be applied to moving pictures with high resolution.

  9. A Fast and Exact Algorithm for the Exemplar Breakpoint Distance.

    PubMed

    Shao, Mingfu; Moret, Bernard M E

    2016-05-01

    A fundamental problem in comparative genomics is to compute the distance between two genomes. For two genomes without duplicate genes, we can easily compute a variety of distance measures in linear time, but the problem is NP-hard under most models when genomes contain duplicate genes. Sankoff proposed the use of exemplars to tackle the problem of duplicate genes and gene families: each gene family is represented by a single gene (the exemplar for that family), chosen so as to optimize some metric. Unfortunately, choosing exemplars is itself an NP-hard problem. In this article, we propose a very fast and exact algorithm to compute the exemplar breakpoint distance, based on new insights in the underlying structure of genome rearrangements and exemplars. We evaluate the performance of our algorithm on simulation data and compare its performance to the best effort to date (a divide-and-conquer approach), showing that our algorithm runs much faster and scales much better. We also devise a new algorithm for the intermediate breakpoint distance problem, which can then be applied to assign orthologs. We compare our algorithm with the state-of-the-art method MSOAR by assigning orthologs among five well annotated mammalian genomes, showing that our algorithm runs much faster and is slightly more accurate than MSOAR. PMID:26953781

  10. A fast algorithm for sparse matrix computations related to inversion

    SciTech Connect

    Li, S.; Wu, W.; Darve, E.

    2013-06-01

    We have developed a fast algorithm for computing certain entries of the inverse of a sparse matrix. Such computations are critical to many applications, such as the calculation of non-equilibrium Green’s functions G{sup r} and G{sup <} for nano-devices. The FIND (Fast Inverse using Nested Dissection) algorithm is optimal in the big-O sense. However, in practice, FIND suffers from two problems due to the width-2 separators used by its partitioning scheme. One problem is the presence of a large constant factor in the computational cost of FIND. The other problem is that the partitioning scheme used by FIND is incompatible with most existing partitioning methods and libraries for nested dissection, which all use width-1 separators. Our new algorithm resolves these problems by thoroughly decomposing the computation process such that width-1 separators can be used, resulting in a significant speedup over FIND for realistic devices — up to twelve-fold in simulation. The new algorithm also has the added advantage that desired off-diagonal entries can be computed for free. Consequently, our algorithm is faster than the current state-of-the-art recursive methods for meshes of any size. Furthermore, the framework used in the analysis of our algorithm is the first attempt to explicitly apply the widely-used relationship between mesh nodes and matrix computations to the problem of multiple eliminations with reuse of intermediate results. This framework makes our algorithm easier to generalize, and also easier to compare against other methods related to elimination trees. Finally, our accuracy analysis shows that the algorithms that require back-substitution are subject to significant extra round-off errors, which become extremely large even for some well-conditioned matrices or matrices with only moderately large condition numbers. When compared to these back-substitution algorithms, our algorithm is generally a few orders of magnitude more accurate, and our produced round

  11. Fast algorithm for calculating chemical kinetics in turbulent reacting flow

    NASA Technical Reports Server (NTRS)

    Radhakrishnan, K.; Pratt, D. T.

    1986-01-01

    This paper addresses the need for a fast batch chemistry solver to perform the kinetics part of a split operator formulation of turbulent reacting flows, with special attention focused on the solution of the ordinary differential equations governing a homogeneous gas-phase chemical reaction. For this purpose, a two-part predictor-corrector algorithm which incorporates an exponentially fitted trapezoidal method was developed. The algorithm performs filtering of ill-posed initial conditions, automatic step-size selection, and automatic selection of Jacobi-Newton or Newton-Raphson iteration for convergence to achieve maximum computational efficiency while observing a prescribed error tolerance. The new algorithm, termed CREK1D (combustion reaction kinetics, one-dimensional), compared favorably with the code LSODE when tested on two representative problems drawn from combustion kinetics, and is faster than LSODE.

  12. A fast image encryption algorithm based on chaotic map

    NASA Astrophysics Data System (ADS)

    Liu, Wenhao; Sun, Kehui; Zhu, Congxu

    2016-09-01

    Derived from Sine map and iterative chaotic map with infinite collapse (ICMIC), a new two-dimensional Sine ICMIC modulation map (2D-SIMM) is proposed based on a close-loop modulation coupling (CMC) model, and its chaotic performance is analyzed by means of phase diagram, Lyapunov exponent spectrum and complexity. It shows that this map has good ergodicity, hyperchaotic behavior, large maximum Lyapunov exponent and high complexity. Based on this map, a fast image encryption algorithm is proposed. In this algorithm, the confusion and diffusion processes are combined for one stage. Chaotic shift transform (CST) is proposed to efficiently change the image pixel positions, and the row and column substitutions are applied to scramble the pixel values simultaneously. The simulation and analysis results show that this algorithm has high security, low time complexity, and the abilities of resisting statistical analysis, differential, brute-force, known-plaintext and chosen-plaintext attacks.

  13. A Fast Conformal Mapping Algorithm with No FFT

    NASA Astrophysics Data System (ADS)

    Luchini, P.; Manzo, F.

    1992-08-01

    An algorithm is presented for the computation of a conformal mapping discretized on a non-uniformly spaced point set, useful for the numerical solution of many problems of fluid dynamics. Most existing iterative techniques, both those having a linear and those having a quadratic type of convergence, rely on the fast Fourier transform ( FFT) algorithm for calculating a convolution integral which represents the most time-consuming phase of the computation. The FFT, however, definitely cannot be applied to a non-uniform spacing. The algorithm presented in this paper has been made possible by the construction of a calculation method for convolution integrals which, despite not using an FFT, maintains a computation time of the same order as that of the FFT. The new technique is successfully applied to the problem of conformally mapping a closely spaced cascade of airfoils onto a circle, which requires an exceedingly large number of points if it is solved with uniform spacing.

  14. The Block V Receiver fast acquisition algorithm for the Galileo S-band mission

    NASA Technical Reports Server (NTRS)

    Aung, M.; Hurd, W. J.; Buu, C. M.; Berner, J. B.; Stephens, S. A.; Gevargiz, J. M.

    1994-01-01

    A fast acquisition algorithm for the Galileo suppressed carrier, subcarrier, and data symbol signals under low data rate, signal-to-noise ratio (SNR) and high carrier phase-noise conditions has been developed. The algorithm employs a two-arm fast Fourier transform (FFT) method utilizing both the in-phase and quadrature-phase channels of the carrier. The use of both channels results in an improved SNR in the FFT acquisition, enabling the use of a shorter FFT period over which the carrier instability is expected to be less significant. The use of a two-arm FFT also enables subcarrier and symbol acquisition before carrier acquisition. With the subcarrier and symbol loops locked first, the carrier can be acquired from an even shorter FFT period. Two-arm tracking loops are employed to lock the subcarrier and symbol loops parameter modification to achieve the final (high) loop SNR in the shortest time possible. The fast acquisition algorithm is implemented in the Block V Receiver (BVR). This article describes the complete algorithm design, the extensive computer simulation work done for verification of the design and the analysis, implementation issues in the BVR, and the acquisition times of the algorithm. In the expected case of the Galileo spacecraft at Jupiter orbit insertion PD/No equals 14.6 dB-Hz, R(sym) equals 16 symbols per sec, and the predicted acquisition time of the algorithm (to attain a 0.2-dB degradation from each loop to the output symbol SNR) is 38 sec.

  15. Fast Three-Dimensional Single-Particle Tracking in Natural Brain Tissue.

    PubMed

    Sokoll, Stefan; Prokazov, Yury; Hanses, Magnus; Biermann, Barbara; Tönnies, Klaus; Heine, Martin

    2015-10-01

    Observation of molecular dynamics is often biased by the optical very heterogeneous environment of cells and complex tissue. Here, we have designed an algorithm that facilitates molecular dynamic analyses within brain slices. We adjust fast astigmatism-based three-dimensional single-particle tracking techniques to depth-dependent optical aberrations induced by the refractive index mismatch so that they are applicable to complex samples. In contrast to existing techniques, our online calibration method determines the aberration directly from the acquired two-dimensional image stream by exploiting the inherent particle movement and the redundancy introduced by the astigmatism. The method improves the positioning by reducing the systematic errors introduced by the aberrations, and allows correct derivation of the cellular morphology and molecular diffusion parameters in three dimensions independently of the imaging depth. No additional experimental effort for the user is required. Our method will be useful for many imaging configurations, which allow imaging in deep cellular structures. PMID:26445447

  16. Vision-based vehicle detection and tracking algorithm design

    NASA Astrophysics Data System (ADS)

    Hwang, Junyeon; Huh, Kunsoo; Lee, Donghwi

    2009-12-01

    The vision-based vehicle detection in front of an ego-vehicle is regarded as promising for driver assistance as well as for autonomous vehicle guidance. The feasibility of vehicle detection in a passenger car requires accurate and robust sensing performance. A multivehicle detection system based on stereo vision has been developed for better accuracy and robustness. This system utilizes morphological filter, feature detector, template matching, and epipolar constraint techniques in order to detect the corresponding pairs of vehicles. After the initial detection, the system executes the tracking algorithm for the vehicles. The proposed system can detect front vehicles such as the leading vehicle and side-lane vehicles. The position parameters of the vehicles located in front are obtained based on the detection information. The proposed vehicle detection system is implemented on a passenger car, and its performance is verified experimentally.

  17. 3DRISM Multigrid Algorithm for Fast Solvation Free Energy Calculations.

    PubMed

    Sergiievskyi, Volodymyr P; Fedorov, Maxim V

    2012-06-12

    In this paper we present a fast and accurate method for modeling solvation properties of organic molecules in water with a main focus on predicting solvation (hydration) free energies of small organic compounds. The method is based on a combination of (i) a molecular theory, three-dimensional reference interaction sites model (3DRISM); (ii) a fast multigrid algorithm for solving the high-dimensional 3DRISM integral equations; and (iii) a recently introduced universal correction (UC) for the 3DRISM solvation free energies by properly scaled molecular partial volume (3DRISM-UC, Palmer et al., J. Phys.: Condens. Matter2010, 22, 492101). A fast multigrid algorithm is the core of the method because it helps to reduce the high computational costs associated with solving the 3DRISM equations. To facilitate future applications of the method, we performed benchmarking of the algorithm on a set of several model solutes in order to find optimal grid parameters and to test the performance and accuracy of the algorithm. We have shown that the proposed new multigrid algorithm is on average 24 times faster than the simple Picard method and at least 3.5 times faster than the MDIIS method which is currently actively used by the 3DRISM community (e.g., the MDIIS method has been recently implemented in a new 3DRISM implicit solvent routine in the recent release of the AmberTools 1.4 molecular modeling package (Luchko et al. J. Chem. Theory Comput. 2010, 6, 607-624). Then we have benchmarked the multigrid algorithm with chosen optimal parameters on a set of 99 organic compounds. We show that average computational time required for one 3DRISM calculation is 3.5 min per a small organic molecule (10-20 atoms) on a standard personal computer. We also benchmarked predicted solvation free energy values for all of the compounds in the set against the corresponding experimental data. We show that by using the proposed multigrid algorithm and the 3DRISM-UC model, it is possible to obtain good

  18. A novel fast median filter algorithm without sorting

    NASA Astrophysics Data System (ADS)

    Yang, Weiping; Zhang, Zhilong; Lu, Xinping; Li, Jicheng; Chen, Dong; Yang, Guopeng

    2016-04-01

    As one of widely applied nonlinear smoothing filtering methods, median filter is quite effective for removing salt-andpepper noise and impulsive noise while maintaining image edge information without blurring its boundaries, but its computation load is the maximal drawback while applied in real-time processing systems. In order to solve the issue, researchers have proposed many effective fast algorithms and published many papers. However most of the algorithms are based on sorting operations so as to make real-time implementation difficult. In this paper considering the large scale Boolean calculation function and convenient shift operation which are two of the advantages of FPGA(Field Programmable Gate Array), we proposed a novel median value finding algorithm without sorting, which can find the median value effectively and its performing time almost keeps changeless despite how large the filter radius is. Based on the algorithm, a real-time median filter has been realized. A lot of tests demonstrate the validity and correctness of proposed algorithm.

  19. Waiting time at a fast-track diagnostic clinic.

    PubMed

    Basta, Y L; Tytgat, K M A J; Klinkenbijl, J H G; Fockens, P; Smets, E M A

    2016-06-13

    Purpose - Guidelines stating maximum waiting times fail to take cancer patients' expectations into account. Therefore, the purpose of this paper is to assess patients' expectations and experiences with their waiting time at a fast-track clinic. Design/methodology/approach - Patients were selected using a purposeful sampling strategy and were interviewed four times: before the visit; one day after; two weeks after the visit; and one week after starting treatment. Interviews were audiotaped and independently coded by two researchers. Findings - All patients (n=9) preferred a short waiting time before the first visit; they feared that their disease would spread and believed that cancer warrants priority treatment. Six patients experienced the waiting time as short, one had no expectations and two felt they waited longer than expected; three patients changed this evaluation during the study. Six patients received treatment - four preferred to wait before treatment and two wanted to start treatment immediately. Reasons to wait included putting one's affairs in order, or needing to adjust to the diagnosis. Practical implications - Cancer patients prefer a short waiting time before the first visit but have different expectations and needs regarding waiting time before treatment. Ideally, their expectations are managed by their treating physician to match waiting time reality. Originality/value - This is the first study to assess cancer patients' waiting time experiences and how these experiences change over time. This study paves the way for establishing a framework to better assess patient satisfaction with oncology care waiting time. An important aspect, is managing patients' expectations. PMID:27256775

  20. Performance evaluation of imaging seeker tracking algorithm based on multi-features

    NASA Astrophysics Data System (ADS)

    Li, Yujue; Yan, Jinglong

    2011-08-01

    The paper presents a new efficient method for performance evaluation of imaging seeker tracking algorithm. The method utilizes multi features which associate with tracking point of each video frame, gets local score(LS) for every feature, and achieves global score(GS) for given tracking algorithm according to the combined strategy. The method can be divided into three steps. In a first step, it extracts evaluation feature from neighbor zone of each tracking point. The feature may include tracking error, shape of target, area of target, tracking path, and so on. Then, as to each feature, a local score can be got rely on the number of target which tracked successfully. It uses similarity measurement and experiential threshold between neighbor zone of tracking point and target template to define tracking successful or not. Of course, the number should be 0 or 1 for single target tracking. Finally, it assigns weight for each feature according to the validity grade for the performance. The weights multiply by local scores and normalized between 0 and 1, this gets global score of certain tracking algorithm. By compare the global score of each tracking algorithm as to certain type of scene, it can evaluate the performance of tracking algorithm quantificational. The proposed method nearly covers all tracking error factors which can be introduced into the process of target tracking, so the evaluation result has a higher reliability. Experimental results, obtained with flying video of infrared imaging seeker, and also included several target tracking algorithms, illustrate the performance of target tracking, demonstrate the effectiveness and robustness of the proposed method.

  1. A fast contour descriptor algorithm for supernova imageclassification

    SciTech Connect

    Aragon, Cecilia R.; Aragon, David Bradburn

    2006-07-16

    We describe a fast contour descriptor algorithm and its application to a distributed supernova detection system (the Nearby Supernova Factory) that processes 600,000 candidate objects in 80 GB of image data per night. Our shape-detection algorithm reduced the number of false positives generated by the supernova search pipeline by 41% while producing no measurable impact on running time. Fourier descriptors are an established method of numerically describing the shapes of object contours, but transform-based techniques are ordinarily avoided in this type of application due to their computational cost. We devised a fast contour descriptor implementation for supernova candidates that meets the tight processing budget of the application. Using the lowest-order descriptors (F{sub 1} and F{sub -1}) and the total variance in the contour, we obtain one feature representing the eccentricity of the object and another denoting its irregularity. Because the number of Fourier terms to be calculated is fixed and small, the algorithm runs in linear time, rather than the O(n log n) time of an FFT. Constraints on object size allow further optimizations so that the total cost of producing the required contour descriptors is about 4n addition/subtraction operations, where n is the length of the contour.

  2. Algorithms for High-Speed Noninvasive Eye-Tracking System

    NASA Technical Reports Server (NTRS)

    Talukder, Ashit; Morookian, John-Michael; Lambert, James

    2010-01-01

    Two image-data-processing algorithms are essential to the successful operation of a system of electronic hardware and software that noninvasively tracks the direction of a person s gaze in real time. The system was described in High-Speed Noninvasive Eye-Tracking System (NPO-30700) NASA Tech Briefs, Vol. 31, No. 8 (August 2007), page 51. To recapitulate from the cited article: Like prior commercial noninvasive eyetracking systems, this system is based on (1) illumination of an eye by a low-power infrared light-emitting diode (LED); (2) acquisition of video images of the pupil, iris, and cornea in the reflected infrared light; (3) digitization of the images; and (4) processing the digital image data to determine the direction of gaze from the centroids of the pupil and cornea in the images. Most of the prior commercial noninvasive eyetracking systems rely on standard video cameras, which operate at frame rates of about 30 Hz. Such systems are limited to slow, full-frame operation. The video camera in the present system includes a charge-coupled-device (CCD) image detector plus electronic circuitry capable of implementing an advanced control scheme that effects readout from a small region of interest (ROI), or subwindow, of the full image. Inasmuch as the image features of interest (the cornea and pupil) typically occupy a small part of the camera frame, this ROI capability can be exploited to determine the direction of gaze at a high frame rate by reading out from the ROI that contains the cornea and pupil (but not from the rest of the image) repeatedly. One of the present algorithms exploits the ROI capability. The algorithm takes horizontal row slices and takes advantage of the symmetry of the pupil and cornea circles and of the gray-scale contrasts of the pupil and cornea with respect to other parts of the eye. The algorithm determines which horizontal image slices contain the pupil and cornea, and, on each valid slice, the end coordinates of the pupil and cornea

  3. The advanced position compensation to improve the dynamic tracking ability for fast moving target in an optoelectronic tracking system

    NASA Astrophysics Data System (ADS)

    Wu, Nengwei; Zhao, Lirong; Zhou, Hui; Chen, Juan

    2005-12-01

    The servo control system of the optoelectronic tracking equipment usually is a kind of SISO. When the fast moving target is tracked, the over-tune of the servo system is the main representation for the dynamic tracking error. As the result, the tracking ability may be improved by limiting the over-tune. We put forward a method, the advanced position compensation (called as APC in short), which is to check the speed-overtune by applying the advanced position information. For the large accelerate target, small over-tune tracking is achieved, but it lowers the ability for tracking the sine signal at low frequency area. While the dynamic high-type can improve the tracking precision for the sine signal at low frequency area, we work out a brand-new method, which combines the advantages of the both. It increases the tracking precision in the whole frequency band at large scale for the optoelectronic tracking system. The simulation results show that when the target moves with the largest accelerate 120°/s2, 120°/s, the maximum static tracking error is about 0.6".

  4. Spermatozoa motion detection and trajectory tracking algorithm based on orthogonal search

    NASA Astrophysics Data System (ADS)

    Chacon Murguia, Mario I.; Valdez Martinez, Antonio

    1999-10-01

    This paper presents a new algorithm for object motion detection and trajectory tracking. This method was developed as part of a machine vision system for human fertility analysis. Fertility analysis is based on the amount of spermatozoa in semen samples and their type of movement. Two approaches were tested to detect the movement of the spermatozoa, image subtraction, and optical flow. Image subtraction is a simple and fast method but it has some complications to detect individual motion when large amounts of objects are presented. The optical flow method is able to detect motion but it turns to be computationally time expensive. It does not generate a specific trajectory of each spermatozoon, and it does not detect static spermatozoa. The algorithm developed detects object motion through an orthogonal search of blocks in consecutive frames. Matching of two blocks in consecutive frames is defined by square differences. A dynamic control array is used to store the trajectory of each spermatozoon, and to deal with all the different situations in the trajectories like, new spermatozoa entering in a frame, spermatozoa leaving the frame, and spermatozoa collision. The algorithm developed turns out to be faster than the optical flow algorithm and solves the problem of the image subtraction method. It also detects static spermatozoa, and generates a motion vector for each spermatozoon that describes their trajectory.

  5. Fast independent component analysis algorithm for quaternion valued signals.

    PubMed

    Javidi, Soroush; Took, Clive Cheong; Mandic, Danilo P

    2011-12-01

    An extension of the fast independent component analysis algorithm is proposed for the blind separation of both Q-proper and Q-improper quaternion-valued signals. This is achieved by maximizing a negentropy-based cost function, and is derived rigorously using the recently developed HR calculus in order to implement Newton optimization in the augmented quaternion statistics framework. It is shown that the use of augmented statistics and the associated widely linear modeling provides theoretical and practical advantages when dealing with general quaternion signals with noncircular (rotation-dependent) distributions. Simulations using both benchmark and real-world quaternion-valued signals support the approach. PMID:22027374

  6. A fast direct sampling algorithm for equilateral closed polygons

    NASA Astrophysics Data System (ADS)

    Cantarella, Jason; Duplantier, Bertrand; Shonkwiler, Clayton; Uehara, Erica

    2016-07-01

    Sampling equilateral closed polygons is of interest in the statistical study of ring polymers. Over the past 30 years, previous authors have proposed a variety of simple Markov chain algorithms (but have not been able to show that they converge to the correct probability distribution) and complicated direct samplers (which require extended-precision arithmetic to evaluate numerically unstable polynomials). We present a simple direct sampler which is fast and numerically stable, and analyze its runtime using a new formula for the volume of equilateral polygon space as a Dirichlet-type integral.

  7. A fast-marching like algorithm for geometrical shock dynamics

    NASA Astrophysics Data System (ADS)

    Noumir, Y.; Le Guilcher, A.; Lardjane, N.; Monneau, R.; Sarrazin, A.

    2015-03-01

    We develop a new algorithm for the computation of the Geometrical Shock Dynamics (GSD) model. The method relies on the fast-marching paradigm and enables the discrete evaluation of the first arrival time of a shock wave and its local velocity on a Cartesian grid. The proposed algorithm is based on a first order upwind finite difference scheme and reduces to a local nonlinear system of two equations solved by an iterative procedure. Reference solutions are built for a smooth radial configuration and for the 2D Riemann problem. The link between the GSD model and p-systems is given. Numerical experiments demonstrate the efficiency of the scheme and its ability to handle singularities.

  8. Fast Particle Pair Detection Algorithms for Particle Simulations

    NASA Astrophysics Data System (ADS)

    Iwai, T.; Hong, C.-W.; Greil, P.

    New algorithms with O(N) complexity have been developed for fast particle-pair detections in particle simulations like the discrete element method (DEM) and molecular dynamic (MD). They exhibit robustness against broad particle size distributions when compared with conventional boxing methods. Almost similar calculation speeds are achieved at particle size distributions from is mono-size to 1:10 while the linked-cell method results in calculations more than 20 times. The basic algorithm, level-boxing, uses the variable search range according to each particle. The advanced method, multi-level boxing, employs multiple cell layers to reduce the particle size discrepancy. Another method, indexed-level boxing, reduces the size of cell arrays by introducing the hash procedure to access the cell array, and is effective for sparse particle systems with a large number of particles.

  9. Fast clustering algorithm for codebook production in image vector quantization

    NASA Astrophysics Data System (ADS)

    Al-Otum, Hazem M.

    2001-04-01

    In this paper, a fast clustering algorithm (FCA) is proposed to be implemented in vector quantization codebook production. This algorithm gives the ability to avoid iterative averaging of vectors and is based on collecting vectors with similar or closely similar characters to produce corresponding clusters. FCA gives an increase in peak signal-to-noise ratio (PSNR) about 0.3 - 1.1 dB, over the LBG algorithm and reduces the computational cost for codebook production (10% - 60%) at different bit rates. Here, two FCA modifications are proposed: FCA with limited cluster size 1& (FCA-LCS1 and FCA-LCS2, respectively). FCA- LCS1 tends to subdivide large clusters into smaller ones while FCA-LCS2 reduces a predetermined threshold by a step to reach the required cluster size. The FCA-LCS1 and FCA- LCS2 give an increase in PSNR of about 0.9 - 1.0 and 0.9 - 1.1 dB, respectively, over the FCA algorithm, at the expense of about 15% - 25% and 18% - 28% increase in the output codebook size.

  10. Peak detection in fiber Bragg grating using a fast phase correlation algorithm

    NASA Astrophysics Data System (ADS)

    Lamberti, A.; Vanlanduit, S.; De Pauw, B.; Berghmans, F.

    2014-05-01

    Fiber Bragg grating sensing principle is based on the exact tracking of the peak wavelength location. Several peak detection techniques have already been proposed in literature. Among these, conventional peak detection (CPD) methods such as the maximum detection algorithm (MDA), do not achieve very high precision and accuracy, especially when the Signal to Noise Ratio (SNR) and the wavelength resolution are poor. On the other hand, recently proposed algorithms, like the cross-correlation demodulation algorithm (CCA), are more precise and accurate but require higher computational effort. To overcome these limitations, we developed a novel fast phase correlation algorithm (FPC) which performs as well as the CCA, being at the same time considerably faster. This paper presents the FPC technique and analyzes its performances for different SNR and wavelength resolutions. Using simulations and experiments, we compared the FPC with the MDA and CCA algorithms. The FPC detection capabilities were as precise and accurate as those of the CCA and considerably better than those of the CPD. The FPC computational time was up to 50 times lower than CCA, making the FPC a valid candidate for future implementation in real-time systems.

  11. Repositioning: the fast track to new anti-malarial medicines?

    PubMed Central

    2014-01-01

    Background Repositioning of existing drugs has been suggested as a fast track for developing new anti-malarial agents. The compound libraries of GlaxoSmithKline (GSK), Pfizer and AstraZeneca (AZ) comprising drugs that have undergone clinical studies in other therapeutic areas, but not achieved approval, and a set of US Food and Drug Administration (FDA)-approved drugs and other bio-actives were tested against Plasmodium falciparum blood stages. Methods Molecules were tested initially against erythrocytic co-cultures of P. falciparum to measure proliferation inhibition using one of the following methods: SYBR®I dye DNA staining assay (3D7, K1 or NF54 strains); [3H] hypoxanthine radioisotope incorporation assay (3D7 and 3D7A strain); or 4’,6-diamidino-2-phenylindole (DAPI) DNA imaging assay (3D7 and Dd2 strains). After review of the available clinical pharmacokinetic and safety data, selected compounds with low μM activity and a suitable clinical profile were tested in vivo either in a Plasmodium berghei four-day test or in the P. falciparum Pf3D70087/N9 huSCID ‘humanized’ mouse model. Results Of the compounds included in the GSK and Pfizer sets, 3.8% (9/238) had relevant in vitro anti-malarial activity while 6/100 compounds from the AZ candidate drug library were active. In comparison, around 0.6% (24/3,800) of the FDA-approved drugs and other bio-actives were active. After evaluation of available clinical data, four investigational drugs, active in vitro were tested in the P. falciparum humanized mouse model: UK-112,214 (PAF-H1 inhibitor), CEP-701 (protein kinase inhibitor), CEP-1347 (protein kinase inhibitor), and PSC-833 (p-glycoprotein inhibitor). Only UK-112,214 showed significant efficacy against P. falciparum in vivo, although at high doses (ED90 131.3 mg/kg [95% CI 112.3, 156.7]), and parasitaemia was still present 96 hours after treatment commencement. Of the six actives from the AZ library, two compounds (AZ-1 and AZ-3) were marginally

  12. Studies of the possibility to use Gas Pixel Detector as a fast trigger tracking device

    NASA Astrophysics Data System (ADS)

    Sinev, N.; Bashindzhagyan, G.; Korotkova, N.; Romaniouk, A.; Tikhomirov, V.

    2016-02-01

    Gas Pixel Detector (GPD) technology offers new possibilities, which make them very attractive for application in existing and future accelerator experiments and beyond. GPDs combine advantages of silicon and gaseous detectors. They can be produced radiation hard and with low power consumption using relatively cheap technology. Low capacitance of the individual pixel channel allows us to obtain a large signal to noise ratio. Using a time projection method for GPD readout one obtains 3D track image with precise coordinate (31 µm) and angular information (0.40°). This feature would allow us to achieve performance of one GPD layer equal to a few layers of silicon detectors. Implementation of a fast readout and data processing at the front-end level allows one to reconstruct a track segment in less than 1 μs, and to use this information for the first level trigger generation. The relevant algorithms of data acquisition and analysis are described and the results of simulations are presented in this paper.

  13. Fast Field Calibration of MIMU Based on the Powell Algorithm

    PubMed Central

    Ma, Lin; Chen, Wanwan; Li, Bin; You, Zheng; Chen, Zhigang

    2014-01-01

    The calibration of micro inertial measurement units is important in ensuring the precision of navigation systems, which are equipped with microelectromechanical system sensors that suffer from various errors. However, traditional calibration methods cannot meet the demand for fast field calibration. This paper presents a fast field calibration method based on the Powell algorithm. As the key points of this calibration, the norm of the accelerometer measurement vector is equal to the gravity magnitude, and the norm of the gyro measurement vector is equal to the rotational velocity inputs. To resolve the error parameters by judging the convergence of the nonlinear equations, the Powell algorithm is applied by establishing a mathematical error model of the novel calibration. All parameters can then be obtained in this manner. A comparison of the proposed method with the traditional calibration method through navigation tests shows the classic performance of the proposed calibration method. The proposed calibration method also saves more time compared with the traditional calibration method. PMID:25177801

  14. Open-source feature-tracking algorithm for sea ice drift retrieval from Sentinel-1 SAR imagery

    NASA Astrophysics Data System (ADS)

    Muckenhuber, Stefan; Andreevich Korosov, Anton; Sandven, Stein

    2016-04-01

    A computationally efficient, open-source feature-tracking algorithm, called ORB, is adopted and tuned for sea ice drift retrieval from Sentinel-1 SAR (Synthetic Aperture Radar) images. The most suitable setting and parameter values have been found using four Sentinel-1 image pairs representative of sea ice conditions between Greenland and Severnaya Zemlya during winter and spring. The performance of the algorithm is compared to two other feature-tracking algorithms, namely SIFT (Scale-Invariant Feature Transform) and SURF (Speeded-Up Robust Features). Having been applied to 43 test image pairs acquired over Fram Strait and the north-east of Greenland, the tuned ORB (Oriented FAST and Rotated BRIEF) algorithm produces the highest number of vectors (177 513, SIFT: 43 260 and SURF: 25 113), while being computationally most efficient (66 s, SIFT: 182 s and SURF: 99 s per image pair using a 2.7 GHz processor with 8 GB memory). For validation purposes, 314 manually drawn vectors have been compared with the closest calculated vectors, and the resulting root mean square error of ice drift is 563 m. All test image pairs show a significantly better performance of the HV (horizontal transmit, vertical receive) channel due to higher informativeness. On average, around four times as many vectors have been found using HV polarization. All software requirements necessary for applying the presented feature-tracking algorithm are open source to ensure a free and easy implementation.

  15. A fast poly-energetic iterative FBP algorithm

    NASA Astrophysics Data System (ADS)

    Lin, Yuan; Samei, Ehsan

    2014-04-01

    The beam hardening (BH) effect can influence medical interpretations in two notable ways. First, high attenuation materials, such as bones, can induce strong artifacts, which severely deteriorate the image quality. Second, voxel values can significantly deviate from the real values, which can lead to unreliable quantitative evaluation results. Some iterative methods have been proposed to eliminate the BH effect, but they cannot be widely applied for clinical practice because of the slow computational speed. The purpose of this study was to develop a new fast and practical poly-energetic iterative filtered backward projection algorithm (piFBP). The piFBP is composed of a novel poly-energetic forward projection process and a robust FBP-type backward updating process. In the forward projection process, an adaptive base material decomposition method is presented, based on which diverse body tissues (e.g., lung, fat, breast, soft tissue, and bone) and metal implants can be incorporated to accurately evaluate poly-energetic forward projections. In the backward updating process, one robust and fast FBP-type backward updating equation with a smoothing kernel is introduced to avoid the noise accumulation in the iteration process and to improve the convergence properties. Two phantoms were designed to quantitatively validate our piFBP algorithm in terms of the beam hardening index (BIdx) and the noise index (NIdx). The simulation results showed that piFBP possessed fast convergence speed, as the images could be reconstructed within four iterations. The variation range of the BIdx's of various tissues across phantom size and spectrum were reduced from [-7.5, 17.5] for FBP to [-0.1, 0.1] for piFBP while the NIdx's were maintained in the same low level (about [0.3, 1.7]). When a metal implant presented in a complex phantom, piFBP still had excellent reconstruction performance, as the variation range of the BIdx's of body tissues were reduced from [-2.9, 15.9] for FBP to [-0

  16. ATLAS Tracking Detector Upgrade studies using the Fast Simulation Engine

    NASA Astrophysics Data System (ADS)

    Calace, Noemi; Salzburger, Andreas

    2015-12-01

    The successful physics program of the LHC Run-1 data taking period has put a strong emphasis on design studies for future upgrades of the existing LHC detectors. In ATLAS, testing alternative layouts through the full simulation and reconstruction chain is a work-intensive program, which can only be carried out for a few concept layouts. To facilitate layout prototyping, a novel technique based on the ATLAS reconstruction geometry and a fast simulation engine have been established that allow fast layout iterations and a realistic but fast Monte Carlo simulation. This approach is extended by a fast digitisation and reconstruction module.

  17. A fast, robust algorithm for power line interference cancellation in neural recording

    NASA Astrophysics Data System (ADS)

    Keshtkaran, Mohammad Reza; Yang, Zhi

    2014-04-01

    Objective. Power line interference may severely corrupt neural recordings at 50/60 Hz and harmonic frequencies. The interference is usually non-stationary and can vary in frequency, amplitude and phase. To retrieve the gamma-band oscillations at the contaminated frequencies, it is desired to remove the interference without compromising the actual neural signals at the interference frequency bands. In this paper, we present a robust and computationally efficient algorithm for removing power line interference from neural recordings. Approach. The algorithm includes four steps. First, an adaptive notch filter is used to estimate the fundamental frequency of the interference. Subsequently, based on the estimated frequency, harmonics are generated by using discrete-time oscillators, and then the amplitude and phase of each harmonic are estimated by using a modified recursive least squares algorithm. Finally, the estimated interference is subtracted from the recorded data. Main results. The algorithm does not require any reference signal, and can track the frequency, phase and amplitude of each harmonic. When benchmarked with other popular approaches, our algorithm performs better in terms of noise immunity, convergence speed and output signal-to-noise ratio (SNR). While minimally affecting the signal bands of interest, the algorithm consistently yields fast convergence (<100 ms) and substantial interference rejection (output SNR >30 dB) in different conditions of interference strengths (input SNR from -30 to 30 dB), power line frequencies (45-65 Hz) and phase and amplitude drifts. In addition, the algorithm features a straightforward parameter adjustment since the parameters are independent of the input SNR, input signal power and the sampling rate. A hardware prototype was fabricated in a 65 nm CMOS process and tested. Software implementation of the algorithm has been made available for open access at https://github.com/mrezak/removePLI. Significance. The proposed

  18. Tracking at CDF: algorithms and experience from Run I and Run II

    SciTech Connect

    Snider, F.D.; /Fermilab

    2005-10-01

    The authors describe the tracking algorithms used during Run I and Run II by CDF at the Fermilab Tevatron Collider, covering the time from about 1992 through the present, and discuss the performance of the algorithms at high luminosity. By tracing the evolution of the detectors and algorithms, they reveal some of the successful strategies used by CDF to address the problems of tracking at high luminosities.

  19. Detection of a Faint Fast-moving Near-Earth Asteroid Using the Synthetic Tracking Technique

    NASA Astrophysics Data System (ADS)

    Zhai, Chengxing; Shao, Michael; Nemati, Bijan; Werne, Thomas; Zhou, Hanying; Turyshev, Slava G.; Sandhu, Jagmit; Hallinan, Gregg; Harding, Leon K.

    2014-09-01

    We report a detection of a faint near-Earth asteroid (NEA) using our synthetic tracking technique and the CHIMERA instrument on the Palomar 200 inch telescope. With an apparent magnitude of 23 (H = 29, assuming detection at 20 lunar distances), the asteroid was moving at 6.°32 day-1 and was detected at a signal-to-noise ratio (S/N) of 15 using 30 s of data taken at a 16.7 Hz frame rate. The detection was confirmed by a second observation 77 minutes later at the same S/N. Because of its high proper motion, the NEA moved 7 arcsec over the 30 s of observation. Synthetic tracking avoided image degradation due to trailing loss that affects conventional techniques relying on 30 s exposures; the trailing loss would have degraded the surface brightness of the NEA image on the CCD down to an approximate magnitude of 25 making the object undetectable. This detection was a result of our 12 hr blind search conducted on the Palomar 200 inch telescope over two nights, scanning twice over six (5.°3 × 0.°046) fields. Detecting only one asteroid is consistent with Harris's estimates for the distribution of the asteroid population, which was used to predict a detection of 1.2 NEAs in the H-magnitude range 28-31 for the two nights. The experimental design, data analysis methods, and algorithms are presented. We also demonstrate milliarcsecond-level astrometry using observations of two known bright asteroids on the same system with synthetic tracking. We conclude by discussing strategies for scheduling observations to detect and characterize small and fast-moving NEAs using the new technique.

  20. Detection of a faint fast-moving near-Earth asteroid using the synthetic tracking technique

    SciTech Connect

    Zhai, Chengxing; Shao, Michael; Nemati, Bijan; Werne, Thomas; Zhou, Hanying; Turyshev, Slava G.; Sandhu, Jagmit; Hallinan, Gregg; Harding, Leon K.

    2014-09-01

    We report a detection of a faint near-Earth asteroid (NEA) using our synthetic tracking technique and the CHIMERA instrument on the Palomar 200 inch telescope. With an apparent magnitude of 23 (H = 29, assuming detection at 20 lunar distances), the asteroid was moving at 6.°32 day{sup –1} and was detected at a signal-to-noise ratio (S/N) of 15 using 30 s of data taken at a 16.7 Hz frame rate. The detection was confirmed by a second observation 77 minutes later at the same S/N. Because of its high proper motion, the NEA moved 7 arcsec over the 30 s of observation. Synthetic tracking avoided image degradation due to trailing loss that affects conventional techniques relying on 30 s exposures; the trailing loss would have degraded the surface brightness of the NEA image on the CCD down to an approximate magnitude of 25 making the object undetectable. This detection was a result of our 12 hr blind search conducted on the Palomar 200 inch telescope over two nights, scanning twice over six (5.°3 × 0.°046) fields. Detecting only one asteroid is consistent with Harris's estimates for the distribution of the asteroid population, which was used to predict a detection of 1.2 NEAs in the H-magnitude range 28-31 for the two nights. The experimental design, data analysis methods, and algorithms are presented. We also demonstrate milliarcsecond-level astrometry using observations of two known bright asteroids on the same system with synthetic tracking. We conclude by discussing strategies for scheduling observations to detect and characterize small and fast-moving NEAs using the new technique.

  1. Fast Dating Using Least-Squares Criteria and Algorithms

    PubMed Central

    To, Thu-Hien; Jung, Matthieu; Lycett, Samantha; Gascuel, Olivier

    2016-01-01

    Phylogenies provide a useful way to understand the evolutionary history of genetic samples, and data sets with more than a thousand taxa are becoming increasingly common, notably with viruses (e.g., human immunodeficiency virus (HIV)). Dating ancestral events is one of the first, essential goals with such data. However, current sophisticated probabilistic approaches struggle to handle data sets of this size. Here, we present very fast dating algorithms, based on a Gaussian model closely related to the Langley–Fitch molecular-clock model. We show that this model is robust to uncorrelated violations of the molecular clock. Our algorithms apply to serial data, where the tips of the tree have been sampled through times. They estimate the substitution rate and the dates of all ancestral nodes. When the input tree is unrooted, they can provide an estimate for the root position, thus representing a new, practical alternative to the standard rooting methods (e.g., midpoint). Our algorithms exploit the tree (recursive) structure of the problem at hand, and the close relationships between least-squares and linear algebra. We distinguish between an unconstrained setting and the case where the temporal precedence constraint (i.e., an ancestral node must be older that its daughter nodes) is accounted for. With rooted trees, the former is solved using linear algebra in linear computing time (i.e., proportional to the number of taxa), while the resolution of the latter, constrained setting, is based on an active-set method that runs in nearly linear time. With unrooted trees the computing time becomes (nearly) quadratic (i.e., proportional to the square of the number of taxa). In all cases, very large input trees (>10,000 taxa) can easily be processed and transformed into time-scaled trees. We compare these algorithms to standard methods (root-to-tip, r8s version of Langley–Fitch method, and BEAST). Using simulated data, we show that their estimation accuracy is similar to

  2. Fast Dating Using Least-Squares Criteria and Algorithms.

    PubMed

    To, Thu-Hien; Jung, Matthieu; Lycett, Samantha; Gascuel, Olivier

    2016-01-01

    Phylogenies provide a useful way to understand the evolutionary history of genetic samples, and data sets with more than a thousand taxa are becoming increasingly common, notably with viruses (e.g., human immunodeficiency virus (HIV)). Dating ancestral events is one of the first, essential goals with such data. However, current sophisticated probabilistic approaches struggle to handle data sets of this size. Here, we present very fast dating algorithms, based on a Gaussian model closely related to the Langley-Fitch molecular-clock model. We show that this model is robust to uncorrelated violations of the molecular clock. Our algorithms apply to serial data, where the tips of the tree have been sampled through times. They estimate the substitution rate and the dates of all ancestral nodes. When the input tree is unrooted, they can provide an estimate for the root position, thus representing a new, practical alternative to the standard rooting methods (e.g., midpoint). Our algorithms exploit the tree (recursive) structure of the problem at hand, and the close relationships between least-squares and linear algebra. We distinguish between an unconstrained setting and the case where the temporal precedence constraint (i.e., an ancestral node must be older that its daughter nodes) is accounted for. With rooted trees, the former is solved using linear algebra in linear computing time (i.e., proportional to the number of taxa), while the resolution of the latter, constrained setting, is based on an active-set method that runs in nearly linear time. With unrooted trees the computing time becomes (nearly) quadratic (i.e., proportional to the square of the number of taxa). In all cases, very large input trees (>10,000 taxa) can easily be processed and transformed into time-scaled trees. We compare these algorithms to standard methods (root-to-tip, r8s version of Langley-Fitch method, and BEAST). Using simulated data, we show that their estimation accuracy is similar to that

  3. Fast imaging system and algorithm for monitoring microlymphatics

    NASA Astrophysics Data System (ADS)

    Akl, T.; Rahbar, E.; Zawieja, D.; Gashev, A.; Moore, J.; Coté, G.

    2010-02-01

    The lymphatic system is not well understood and tools to quantify aspects of its behavior are needed. A technique to monitor lymph velocity that can lead to flow, the main determinant of transport, in a near real time manner can be extremely valuable. We recently built a new system that measures lymph velocity, vessel diameter and contractions using optical microscopy digital imaging with a high speed camera (500fps) and a complex processing algorithm. The processing time for a typical data period was significantly reduced to less than 3 minutes in comparison to our previous system in which readings were available 30 minutes after the vessels were imaged. The processing was based on a correlation algorithm in the frequency domain, which, along with new triggering methods, reduced the processing and acquisition time significantly. In addition, the use of a new data filtering technique allowed us to acquire results from recordings that were irresolvable by the previous algorithm due to their high noise level. The algorithm was tested by measuring velocities and diameter changes in rat mesenteric micro-lymphatics. We recorded velocities of 0.25mm/s on average in vessels of diameter ranging from 54um to 140um with phasic contraction strengths of about 6 to 40%. In the future, this system will be used to monitor acute effects that are too fast for previous systems and will also increase the statistical power when dealing with chronic changes. Furthermore, we plan on expanding its functionality to measure the propagation of the contractile activity.

  4. Improvement in fast particle track reconstruction with robust statistics

    NASA Astrophysics Data System (ADS)

    Aartsen, M. G.; Abbasi, R.; Abdou, Y.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Altmann, D.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Baum, V.; Bay, R.; Beatty, J. J.; Bechet, S.; Becker Tjus, J.; Becker, K.-H.; Benabderrahmane, M. L.; BenZvi, S.; Berghaus, P.; Berley, D.; Bernardini, E.; Bernhard, A.; Besson, D. Z.; Binder, G.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohaichuk, S.; Bohm, C.; Bose, D.; Böser, S.; Botner, O.; Brayeur, L.; Bretz, H.-P.; Brown, A. M.; Bruijn, R.; Brunner, J.; Carson, M.; Casey, J.; Casier, M.; Chirkin, D.; Christov, A.; Christy, B.; Clark, K.; Clevermann, F.; Coenders, S.; Cohen, S.; Cowen, D. F.; Cruz Silva, A. H.; Danninger, M.; Daughhetee, J.; Davis, J. C.; Day, M.; De Clercq, C.; De Ridder, S.; Desiati, P.; de Vries, K. D.; de With, M.; DeYoung, T.; Díaz-Vélez, J. C.; Dunkman, M.; Eagan, R.; Eberhardt, B.; Eisch, J.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feintzeig, J.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Flis, S.; Franckowiak, A.; Frantzen, K.; Fuchs, T.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Golup, G.; Gonzalez, J. G.; Goodman, J. A.; Góra, D.; Grandmont, D. T.; Grant, D.; Groß, A.; Ha, C.; Haj Ismail, A.; Hallen, P.; Hallgren, A.; Halzen, F.; Hanson, K.; Heereman, D.; Heinen, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Homeier, A.; Hoshina, K.; Huelsnitz, W.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jacobi, E.; Jacobsen, J.; Jagielski, K.; Japaridze, G. S.; Jero, K.; Jlelati, O.; Kaminsky, B.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kiryluk, J.; Kläs, J.; Klein, S. R.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Krasberg, M.; Krings, K.; Kroll, G.; Kunnen, J.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Landsman, H.; Larson, M. J.; Lesiak-Bzdak, M.; Leuermann, M.; Leute, J.; Lünemann, J.; Macías, O.; Madsen, J.; Maggi, G.; Maruyama, R.; Mase, K.; Matis, H. S.; McNally, F.; Meagher, K.; Merck, M.; Meures, T.; Miarecki, S.; Middell, E.; Milke, N.; Miller, J.; Mohrmann, L.; Montaruli, T.; Morse, R.; Nahnhauer, R.; Naumann, U.; Niederhausen, H.; Nowicki, S. C.; Nygren, D. R.; Obertacke, A.; Odrowski, S.; Olivas, A.; Omairat, A.; O'Murchadha, A.; Paul, L.; Pepper, J. A.; Pérez de los Heros, C.; Pfendner, C.; Pieloth, D.; Pinat, E.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Rädel, L.; Rameez, M.; Rawlins, K.; Redl, P.; Reimann, R.; Resconi, E.; Rhode, W.; Ribordy, M.; Richman, M.; Riedel, B.; Rodrigues, J. P.; Rott, C.; Ruhe, T.; Ruzybayev, B.; Ryckbosch, D.; Saba, S. M.; Salameh, T.; Sander, H.-G.; Santander, M.; Sarkar, S.; Schatto, K.; Scheriau, F.; Schmidt, T.; Schmitz, M.; Schoenen, S.; Schöneberg, S.; Schönwald, A.; Schukraft, A.; Schulte, L.; Schulz, O.; Seckel, D.; Sestayo, Y.; Seunarine, S.; Shanidze, R.; Sheremata, C.; Smith, M. W. E.; Soldin, D.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stasik, A.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Strahler, E. A.; Ström, R.; Sullivan, G. W.; Taavola, H.; Taboada, I.; Tamburro, A.; Tepe, A.; Ter-Antonyan, S.; Tešić, G.; Tilav, S.; Toale, P. A.; Toscano, S.; Unger, E.; Usner, M.; Vallecorsa, S.; van Eijndhoven, N.; Van Overloop, A.; van Santen, J.; Vehring, M.; Voge, M.; Vraeghe, M.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Weaver, Ch.; Wellons, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Williams, D. R.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, D. L.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; Ziemann, J.; Zierke, S.; Zoll, M.; Recht, B.; Ré, C.

    2014-02-01

    The IceCube project has transformed 1 km3 of deep natural Antarctic ice into a Cherenkov detector. Muon neutrinos are detected and their direction is inferred by mapping the light produced by the secondary muon track inside the volume instrumented with photomultipliers. Reconstructing the muon track from the observed light is challenging due to noise, light scattering in the ice medium, and the possibility of simultaneously having multiple muons inside the detector, resulting from the large flux of cosmic ray muons. This paper describes work on two problems: (1) the track reconstruction problem, in which, given a set of observations, the goal is to recover the track of a muon; and (2) the coincident event problem, which is to determine how many muons are active in the detector during a time window. Rather than solving these problems by developing more complex physical models that are applied at later stages of the analysis, our approach is to augment the detector's early reconstruction with data filters and robust statistical techniques. These can be implemented at the level of on-line reconstruction and, therefore, improve all subsequent reconstructions. Using the metric of median angular resolution, a standard metric for track reconstruction, we improve the accuracy in the initial reconstruction direction by 13%. We also present improvements in measuring the number of muons in coincident events: we can accurately determine the number of muons 98% of the time.

  5. The Fleet Application for Scheduling and Tracking (FAST) Management Website

    NASA Technical Reports Server (NTRS)

    Marrero-Perez, Radames J.

    2014-01-01

    The FAST application was designed to replace the paper and pen method of checking out and checking in GSA Vehicles at KSC. By innovating from a paper and pen based checkout system to a fully digital one, not only the resources wasted by printing the checkout forms have been reduced, but it also reduces significantly the time that users and fleet managers need to interact with the system as well as improving the record accuracy for each vehicle. The vehicle information is pulled from a centralized database server in the SPSDL. In an attempt to add a new feature to the FAST application, the author of this report (alongside the FAST developers) has been designing and developing the FAST Management Website. The GSA fleet managers had to rely on the FAST developers in order to add new vehicles, edit vehicles and previous transactions, or for generating vehicles reports. By providing an easy-to-use FAST Management Website portal, the GSA fleet managers are now able to easily move vehicles, edit records, and print reports.

  6. A fast algorithm for the phonemic segmentation of continuous speech

    NASA Astrophysics Data System (ADS)

    Smidt, D.

    1986-04-01

    The method of differential learning (DL method) was applied to the fast phonemic classification of acoustic speech spectra. The method was also tested with a simple algorithm for continuous speech recognition. In every learning step of the DL method only that single pattern component which deviates most from the reference value is used for a new rule. Several rules of this type were connected in a conjunctive or disjunctive way. Tests with a single speaker demonstrate good classification capability and a very high speed. The inclusion of automatically additional features selected according to their relevance is discussed. It is shown that there exists a correspondence between processes related to the DL method and pattern recognition in living beings with their ability for generalization and differentiation.

  7. Fast Probabilistic Particle Identification algorithm using silicon strip detectors

    NASA Astrophysics Data System (ADS)

    Di Fino, L.; Zaconte, V.; Ciccotelli, A.; Larosa, M.; Narici, L.

    2012-08-01

    Active detectors used as radiation monitors in space are not usually able to perform Particle Identification (PID). Common techniques need energy loss spectra with high statistics to estimate ion abundances. The ALTEA-space detector system is a set of silicon strip particle telescopes monitoring the radiation environment on board the International Space Station since July 2006 with real-time telemetry capabilities. Its large geometrical factor due to the concurrent use of six detectors permits the acquisition of good energy loss spectra even in a short period of observation. In this paper we present a novel Fast Probabilistic Particle Identification (FPPI) algorithm developed for the ALTEA data analysis in order to perform nuclear identification with low statistics and, with some limitations, also in real time.

  8. Fast volume rendering algorithm in a virtual endoscopy system

    NASA Astrophysics Data System (ADS)

    Kim, Sang H.; Kim, Jin K.; Ra, Jong Beom

    2002-05-01

    Recently, 3D virtual endoscopy has been used as an alternative noninvasive procedure for visualization of a hollow organ. In this paper, we propose a fast volume rendering scheme based on perspective ray casting for virtual endoscopy. As a pre-processing step, the algorithm divides a volume into hierarchical blocks and classifies them into opaque or transparent blocks. Then, the rendering procedure is as follows. In the first step, we perform ray casting only for sub-sampled pixels on the image plane, and determine their pixel values and depth information. In the second step, by reducing the sub-sampling factor by half, we repeat ray casting for newly added pixels, and their pixel values and depth information are determined. Here, the previously obtained depth information is utilized to reduce the processing time. This step is performed recursively until the full-size rendering image is acquired. Experiments conducted on a PC shows that the proposed algorithm can reduce the rendering time by 70-80% for the bronchus and colon endoscopy, compared with the brute-force ray casting scheme. Thereby, interactive rendering becomes more realizable in a PC environment without any specific hardware.

  9. Fast half-sibling population reconstruction: theory and algorithms

    PubMed Central

    2013-01-01

    Background Kinship inference is the task of identifying genealogically related individuals. Kinship information is important for determining mating structures, notably in endangered populations. Although many solutions exist for reconstructing full sibling relationships, few exist for half-siblings. Results We consider the problem of determining whether a proposed half-sibling population reconstruction is valid under Mendelian inheritance assumptions. We show that this problem is NP-complete and provide a 0/1 integer program that identifies the minimum number of individuals that must be removed from a population in order for the reconstruction to become valid. We also present SibJoin, a heuristic-based clustering approach based on Mendelian genetics, which is strikingly fast. The software is available at http://github.com/ddexter/SibJoin.git+. Conclusions Our SibJoin algorithm is reasonably accurate and thousands of times faster than existing algorithms. The heuristic is used to infer a half-sibling structure for a population which was, until recently, too large to evaluate. PMID:23849037

  10. A guidance and control algorithm for scent tracking micro-robotic vehicle swarms

    SciTech Connect

    Dohner, J.L.

    1998-03-01

    Cooperative micro-robotic scent tracking vehicles are designed to collectively sniff out locations of high scent concentrations in unknown, geometrically complex environments. These vehicles are programmed with guidance and control algorithms that allow inter cooperation among vehicles. In this paper a cooperative guidance and control algorithm for scent tracking micro-robotic vehicles is presented. This algorithm is comprised of a sensory compensation sub-algorithm using point source cancellation, a guidance sub-algorithm using gradient descent tracking, and a control sub-algorithm using proportional feedback. The concepts of social rank and point source cancellation are new concepts introduced within. Simulation results for cooperative vehicles swarms are given. Limitations are discussed.

  11. Implementation of the fast track surgery in patients undergoing the colonic resection: own experience.

    PubMed

    Morończyk, Daniel Antoni F; Krasnodębski, Ireneusz Wojciech

    2011-09-01

    A perioperative care in the colorectal surgery has been considerably changed recently. The fast track surgery decreases complications rate, shortens length of stay, improves quality of life and leads to cost reduction. It is achieved by: resignation of a mechanical bowel preparation before and a nasogastric tube insertion after operation, optimal pain and intravenous fluid management, an early rehabilitation, enteral nutrition and removal of a vesical catheter and abdominal drain if used.The aim of the study was to compare the results of an implementation the fast track surgery protocol with results achieving in the conventional care regimen.Material and methods. Two groups of patients undergoing colonic resection have been compared. The study group was formed by patients treated with fast track concept, the control group - by patients who were dealt with hitherto regimen. Procedures needed stoma performing, rectal and laparoscopic surgery were excluded. The perioperative period was investigated by telephone call to patient or his family.Results. Statistical significant reduction was reached in a favour of the fast track group in the following parameters: the length of hospital stay (2.5 days shorter), duration of an abdominal cavity and vesicle drainage (3 and 2 days shorter respectively), postoperative day on which oral diet was implemented (2,5 days faster) and finally extended (1.5 days faster). There were no statistical difference in mortality, morbidity neither reoperation rate between two groups.Conclusion. The fast track surgery is a safe strategy and may improve a perioperative care. PMID:22166736

  12. Modal analysis of rotating plate using tracking laser Doppler vibrometer: algorithm modification

    NASA Astrophysics Data System (ADS)

    Khalil, Hossam; Kim, Dongkyu; Nam, Joonsik; Park, Kyihwan

    2015-07-01

    A modified algorithm for tracking laser Doppler vibrometer (TLDV) is introduced to measure the vibration of rotating objects. The proposed algorithm unlike the old algorithm for TLDV can be used when the speed of the object to be tracked varies continuously or alternating in a small range. The proposed algorithm is to use encoder only as a position sensor. The position from the encoder is used to calculate the driving signals to the galvanometers. To verify the proposed method, experimental modal analysis of the circular plate in stationary and rotating cases are made.

  13. A group tracking algorithm for ground vehicle convoys

    NASA Astrophysics Data System (ADS)

    Chin, Wei C.; Lee, Hian B.; Xiao, Xu H.; Ng, Gee W.; How, Khee Y.

    2005-03-01

    Tracking multiple ground targets under clutter and in real time poses several likely challenges: vehicles often get masked by foliage or line-of-sight (LOS) problems, manifesting in misdetections and false alarms. Further complications also arise when groups of vehicles merge or split. This paper presents an attempt to address these issues using a group tracking approach. Group tracking is a way to ameliorate, or at least soften the impact of such issues from the hope that at least partial information will be received from each target group even when the probability of detection, PD of each individual member is low. A Strongest Neighbour Association (SNA) method of measurement-to-track association based on space-time reasoning and track-measurement similarity measures has been derived. We combine the association strengths of the space-time dynamics, the degree-of-overlap and the historical affinity metrics to relate measurements and tracks. The state estimation is based on standard Kalman filter. Lastly, a Pairwise Historical Affinity Ratios (PHAR) is proposed for the detection of a split scenario. This method has been tested to work well on a simulated convoy-splitting scenario. Monte Carlo experiment runs of six different error rates with five different compositions of errors have been conducted to assess the performance of the tracker. Results indicated that the group tracker remains robust (>80% precision) even in the presence of high individual source track error rates of up to 30%.

  14. Design of a hardware track finder (Fast Tracker) for the ATLAS trigger

    NASA Astrophysics Data System (ADS)

    Cavaliere, V.; Adelman, J.; Albicocco, P.; Alison, J.; Ancu, L. S.; Anderson, J.; Andari, N.; Andreani, A.; Andreazza, A.; Annovi, A.; Antonelli, M.; Asbah, N.; Atkinson, M.; Baines, J.; Barberio, E.; Beccherle, R.; Beretta, M.; Bertolucci, F.; Biesuz, N. V.; Blair, R.; Bogdan, M.; Boveia, A.; Britzger, D.; Bryant, P.; Burghgrave, B.; Calderini, G.; Camplani, A.; Cavasinni, V.; Chakraborty, D.; Chang, P.; Cheng, Y.; Citraro, S.; Citterio, M.; Crescioli, F.; Dawe, N.; Dell'Orso, M.; Donati, S.; Dondero, P.; Drake, G.; Gadomski, S.; Gatta, M.; Gentsos, C.; Giannetti, P.; Gkaitatzis, S.; Gramling, J.; Howarth, J. W.; Iizawa, T.; Ilic, N.; Jiang, Z.; Kaji, T.; Kasten, M.; Kawaguchi, Y.; Kim, Y. K.; Kimura, N.; Klimkovich, T.; Kolb, M.; Kordas, K.; Krizka, K.; Kubota, T.; Lanza, A.; Li, H. L.; Liberali, V.; Lisovyi, M.; Liu, L.; Love, J.; Luciano, P.; Luongo, C.; Magalotti, D.; Maznas, I.; Meroni, C.; Mitani, T.; Nasimi, H.; Negri, A.; Neroutsos, P.; Neubauer, M.; Nikolaidis, S.; Okumura, Y.; Pandini, C.; Petridou, C.; Piendibene, M.; Proudfoot, J.; Rados, P.; Roda, C.; Rossi, E.; Sakurai, Y.; Sampsonidis, D.; Saxon, J.; Schmitt, S.; Schoening, A.; Shochet, M.; Shojaii, S.; Soltveit, H.; Sotiropoulou, C. L.; Stabile, A.; Swiatlowski, M.; Tang, F.; Taylor, P. T.; Testa, M.; Tompkins, L.; Vercesi, V.; Volpi, G.; Wang, R.; Watari, R.; Webster, J.; Wu, X.; Yorita, K.; Yurkewicz, A.; Zeng, J. C.; Zhang, J.; Zou, R.

    2016-02-01

    The use of tracking information at the trigger level in the LHC Run II period is crucial for the trigger and data acquisition system and will be even more so as contemporary collisions that occur at every bunch crossing will increase in Run III. The Fast TracKer is part of the ATLAS trigger upgrade project; it is a hardware processor that will provide every Level-1 accepted event (100 kHz) and within 100μs, full tracking information for tracks with momentum as low as 1 GeV . Providing fast, extensive access to tracking information, with resolution comparable to the offline reconstruction, FTK will help in precise detection of the primary and secondary vertices to ensure robust selections and improve the trigger performance.

  15. Note: Fast neutron efficiency in CR-39 nuclear track detectors

    SciTech Connect

    Cavallaro, S.

    2015-03-15

    CR-39 samples are commonly employed for fast neutron detection in fusion reactors and in inertial confinement fusion experiments. The literature reported efficiencies are strongly depending on experimental conditions and, in some cases, highly dispersed. The present note analyses the dependence of efficiency as a function of various parameters and experimental conditions in both the radiator-assisted and the stand-alone CR-39 configurations. Comparisons of literature experimental data with Monte Carlo calculations and optimized efficiency values are shown and discussed.

  16. Fast and long term lipid droplet tracking with CARS microscopy.

    PubMed

    Jüngst, Christian; Winterhalder, Martin J; Zumbusch, Andreas

    2011-06-01

    Photobleaching of organic fluorophores commonly used in fluorescence microscopy puts a limit to the number of images which can be acquired. Label-free imaging techniques therefore offer advantages both for rapid image acquisition and for long-term observations. CARS microscopy is a label-free imaging technique offering molecule specific contrast. Here we demonstrate that CARS microscopy allows video-rate tracking of intracellular transport of lipid droplets, but also continuous long-term observation of cells over several hours. PMID:21445955

  17. Biased Randomized Algorithm for Fast Model-Based Diagnosis

    NASA Technical Reports Server (NTRS)

    Williams, Colin; Vartan, Farrokh

    2005-01-01

    A biased randomized algorithm has been developed to enable the rapid computational solution of a propositional- satisfiability (SAT) problem equivalent to a diagnosis problem. The closest competing methods of automated diagnosis are described in the preceding article "Fast Algorithms for Model-Based Diagnosis" and "Two Methods of Efficient Solution of the Hitting-Set Problem" (NPO-30584), which appears elsewhere in this issue. It is necessary to recapitulate some of the information from the cited articles as a prerequisite to a description of the present method. As used here, "diagnosis" signifies, more precisely, a type of model-based diagnosis in which one explores any logical inconsistencies between the observed and expected behaviors of an engineering system. The function of each component and the interconnections among all the components of the engineering system are represented as a logical system. Hence, the expected behavior of the engineering system is represented as a set of logical consequences. Faulty components lead to inconsistency between the observed and expected behaviors of the system, represented by logical inconsistencies. Diagnosis - the task of finding the faulty components - reduces to finding the components, the abnormalities of which could explain all the logical inconsistencies. One seeks a minimal set of faulty components (denoted a minimal diagnosis), because the trivial solution, in which all components are deemed to be faulty, always explains all inconsistencies. In the methods of the cited articles, the minimal-diagnosis problem is treated as equivalent to a minimal-hitting-set problem, which is translated from a combinatorial to a computational problem by mapping it onto the Boolean-satisfiability and integer-programming problems. The integer-programming approach taken in one of the prior methods is complete (in the sense that it is guaranteed to find a solution if one exists) and slow and yields a lower bound on the size of the

  18. Restoring integrity—A grounded theory of coping with a fast track surgery programme

    PubMed Central

    Jørgensen, Lene Bastrup; Fridlund, Bengt

    2016-01-01

    Aims and objectives The aim of this study was to generate a theory conceptualizing and explaining behavioural processes involved in coping in order to identify the predominant coping types and coping type-specific features. Background Patients undergoing fast track procedures do not experience a higher risk of complications, readmission, or mortality. However, such programmes presuppose an increasing degree of patient involvement, placing high educational, physical, and mental demands on the patients. There is a lack of knowledge about how patients understand and cope with fast track programmes. Design The study design used classical grounded theory. Methods The study used a multimodal approach with qualitative and quantitative data sets from 14 patients. Results Four predominant types of coping, with distinct physiological, cognitive, affective, and psychosocial features, existed among patients going through a fast track total hip replacement programme. These patients’ main concern was to restore their physical and psychosocial integrity, which had been compromised by reduced function and mobility in daily life. To restore integrity they economized their mental resources, while striving to fulfil the expectations of the fast track programme. This goal was achieved by being mentally proactive and physically active. Three out of the four predominant types of coping matched the expectations expressed in the fast track programme. The non-matching behaviour was seen among the most nervous patients, who claimed the right to diverge from the programme. Conclusion In theory, four predominant types of coping with distinct physiological, cognitive, affective, and psychosocial features occur among patients going through a fast track total hip arthroplasty programme. PMID:26751199

  19. Surface track potential created by fast protons at LiF surfaces

    NASA Astrophysics Data System (ADS)

    Arnau, A.; Gravielle, M. S.; Miraglia, J. E.; Ponce, V. H.

    2003-06-01

    A model based on atomic ionization of F- sites at the surface is used to calculate the surface track potential created by fast protons at LiF surfaces. For 100-keV protons at grazing incidence, we find that the track potential close to the surface plays a significant role in determining the shift to lower energies of the convoy electron peak with respect to the unperturbed cusp value.

  20. Visual Tracking Based on an Improved Online Multiple Instance Learning Algorithm.

    PubMed

    Wang, Li Jia; Zhang, Hua

    2016-01-01

    An improved online multiple instance learning (IMIL) for a visual tracking algorithm is proposed. In the IMIL algorithm, the importance of each instance contributing to a bag probability is with respect to their probabilities. A selection strategy based on an inner product is presented to choose weak classifier from a classifier pool, which avoids computing instance probabilities and bag probability M times. Furthermore, a feedback strategy is presented to update weak classifiers. In the feedback update strategy, different weights are assigned to the tracking result and template according to the maximum classifier score. Finally, the presented algorithm is compared with other state-of-the-art algorithms. The experimental results demonstrate that the proposed tracking algorithm runs in real-time and is robust to occlusion and appearance changes. PMID:26843855

  1. Visual Tracking Based on an Improved Online Multiple Instance Learning Algorithm

    PubMed Central

    Wang, Li Jia; Zhang, Hua

    2016-01-01

    An improved online multiple instance learning (IMIL) for a visual tracking algorithm is proposed. In the IMIL algorithm, the importance of each instance contributing to a bag probability is with respect to their probabilities. A selection strategy based on an inner product is presented to choose weak classifier from a classifier pool, which avoids computing instance probabilities and bag probability M times. Furthermore, a feedback strategy is presented to update weak classifiers. In the feedback update strategy, different weights are assigned to the tracking result and template according to the maximum classifier score. Finally, the presented algorithm is compared with other state-of-the-art algorithms. The experimental results demonstrate that the proposed tracking algorithm runs in real-time and is robust to occlusion and appearance changes. PMID:26843855

  2. An Improved Wake Vortex Tracking Algorithm for Multiple Aircraft

    NASA Technical Reports Server (NTRS)

    Switzer, George F.; Proctor, Fred H.; Ahmad, Nashat N.; LimonDuparcmeur, Fanny M.

    2010-01-01

    The accurate tracking of vortex evolution from Large Eddy Simulation (LES) data is a complex and computationally intensive problem. The vortex tracking requires the analysis of very large three-dimensional and time-varying datasets. The complexity of the problem is further compounded by the fact that these vortices are embedded in a background turbulence field, and they may interact with the ground surface. Another level of complication can arise, if vortices from multiple aircrafts are simulated. This paper presents a new technique for post-processing LES data to obtain wake vortex tracks and wake intensities. The new approach isolates vortices by defining "regions of interest" (ROI) around each vortex and has the ability to identify vortex pairs from multiple aircraft. The paper describes the new methodology for tracking wake vortices and presents application of the technique for single and multiple aircraft.

  3. Multiphase Interface Tracking with Fast Semi-Lagrangian Contouring.

    PubMed

    Li, Xiaosheng; He, Xiaowei; Liu, Xuehui; Zhang, Jian J; Liu, Baoquan; Wu, Enhua

    2016-08-01

    We propose a semi-Lagrangian method for multiphase interface tracking. In contrast to previous methods, our method maintains an explicit polygonal mesh, which is reconstructed from an unsigned distance function and an indicator function, to track the interface of arbitrary number of phases. The surface mesh is reconstructed at each step using an efficient multiphase polygonization procedure with precomputed stencils while the distance and indicator function are updated with an accurate semi-Lagrangian path tracing from the meshes of the last step. Furthermore, we provide an adaptive data structure, multiphase distance tree, to accelerate the updating of both the distance function and the indicator function. In addition, the adaptive structure also enables us to contour the distance tree accurately with simple bisection techniques. The major advantage of our method is that it can easily handle topological changes without ambiguities and preserve both the sharp features and the volume well. We will evaluate its efficiency, accuracy and robustness in the results part with several examples. PMID:26353373

  4. An effective automatic tracking algorithm based on Camshift and Kalman filter

    NASA Astrophysics Data System (ADS)

    Liang, Juan; Hou, Jianhua; Xiang, Jun; Da, Bangyou; Chen, Shaobo

    2011-11-01

    An automatic tracking algorithm based on Camshift and Kalman filter is proposed in this paper to deal with the problems in traditional Camshift algorithm, such as artificial orientation and increasing possibility of tracking failure under occlusion. The inter-frame difference and canny edge detection are combined to segment perfect moving object region accurately, and the center point of the region is obtained as the initial position of the object. With regard to tracking under occlusion, Kalman filter is used to predict the position and velocity of the target. Specifically, the initial iterative position of Camshift algorithm is obtained by Kalman filter in every frame, and then Camshift algorithm is utilized to track the target position. Finally, the parameters of adaptive Kalman filter are updated by the optimal position. However, when severe occlusion appears, the optimal position calculated by Camshift algorithm is inaccurate, and the Kalman filter fails to estimate the coming state effectively. In this situation, the Kalman filter is updated by the Kalman predictive value instead of the value calculated by the Camshift algorithm. The experiment results demonstrate that the proposed algorithm can detect and track the target object accurately and has better robustness to occlusion.

  5. Note: fast neutron efficiency in CR-39 nuclear track detectors.

    PubMed

    Cavallaro, S

    2015-03-01

    CR-39 samples are commonly employed for fast neutron detection in fusion reactors and in inertial confinement fusion experiments. The literature reported efficiencies are strongly depending on experimental conditions and, in some cases, highly dispersed. The present note analyses the dependence of efficiency as a function of various parameters and experimental conditions in both the radiator-assisted and the stand-alone CR-39 configurations. Comparisons of literature experimental data with Monte Carlo calculations and optimized efficiency values are shown and discussed. PMID:25832287

  6. An algorithm for fast DNS cavitating flows simulations using homogeneous mixture approach

    NASA Astrophysics Data System (ADS)

    Žnidarčič, A.; Coutier-Delgosha, O.; Marquillie, M.; Dular, M.

    2015-12-01

    A new algorithm for fast DNS cavitating flows simulations is developed. The algorithm is based on Kim and Moin projection method form. Homogeneous mixture approach with transport equation for vapour volume fraction is used to model cavitation and various cavitation models can be used. Influence matrix and matrix diagonalisation technique enable fast parallel computations.

  7. A simple backscattering microscope for fast tracking of biological molecules.

    PubMed

    Sowa, Yoshiyuki; Steel, Bradley C; Berry, Richard M

    2010-11-01

    Recent developments in techniques for observing single molecules under light microscopes have helped reveal the mechanisms by which molecular machines work. A wide range of markers can be used to detect molecules, from single fluorophores to micron sized markers, depending on the research interest. Here, we present a new and simple objective-type backscattering microscope to track gold nanoparticles with nanometer and microsecond resolution. The total noise of our system in a 55 kHz bandwidth is ~0.6 nm per axis, sufficient to measure molecular movement. We found our backscattering microscopy to be useful not only for in vitro but also for in vivo experiments because of lower background scattering from cells than in conventional dark-field microscopy. We demonstrate the application of this technique to measuring the motion of a biological rotary molecular motor, the bacterial flagellar motor, in live Escherichia coli cells. PMID:21133475

  8. L1Track: A fast Level 1 track trigger for the ATLAS high luminosity upgrade

    NASA Astrophysics Data System (ADS)

    Cerri, Alessandro

    2016-07-01

    With the planned high-luminosity upgrade of the LHC (HL-LHC), the ATLAS detector will see its collision rate increase by approximately a factor of 5 with respect to the current LHC operation. The earliest hardware-based ATLAS trigger stage ("Level 1") will have to provide a higher rejection factor in a more difficult environment: a new improved Level 1 trigger architecture is under study, which includes the possibility of extracting with low latency and high accuracy tracking information in time for the decision taking process. In this context, the feasibility of potential approaches aimed at providing low-latency high-quality tracking at Level 1 is discussed.

  9. Lightning Jump Algorithm and Relation to Thunderstorm Cell Tracking, GLM Proxy and other Meteorological Measurements

    NASA Technical Reports Server (NTRS)

    Schultz, Christopher J.; Carey, Larry; Cecil, Dan; Bateman, Monte; Stano, Geoffrey; Goodman, Steve

    2012-01-01

    Objective of project is to refine, adapt and demonstrate the Lightning Jump Algorithm (LJA) for transition to GOES -R GLM (Geostationary Lightning Mapper) readiness and to establish a path to operations Ongoing work . reducing risk in GLM lightning proxy, cell tracking, LJA algorithm automation, and data fusion (e.g., radar + lightning).

  10. A novel track reconstruction algorithm for photoelectric X-ray polarimetry

    NASA Astrophysics Data System (ADS)

    Li, Tenglin; Li, Hong; Feng, Hua; Zeng, Ming

    2016-07-01

    The key to the photoelectric X-ray polarimetry is the determination of the emission direction of photoelectrons. Due to the low mass of an electron, the ionization track is not straight and the useful information is stored only in its initial part where less energy is deposited. We present a new algorithm in order to reconstruct the electron track from a 2D track image that is blurred due to diffusion during drift in the gas chamber. The algorithm is based on the shortest path problem in graph theory, and a spatial energy filter is implemented as an improvement. Tested with simulated data, which approximate the real measurement with the gas pixel detector, we find that the new algorithm is able to trace the initial part of the track more closely and produce a higher degree of modulation than past algorithms, especially for long tracks created by high energy X-rays, in which cases the past algorithms may fail due to complicated track patterns.

  11. Fast Flux Test Facility Asbestos Location Tracking Program

    SciTech Connect

    REYNOLDS, J.A.

    1999-04-13

    Procedure Number HNF-PRO-408, revision 0, paragraph 1.0, ''Purpose,'' and paragraph 2.0, ''Requirements for Facility Management of Asbestos,'' relate building inspection and requirements for documentation of existing asbestos-containing building material (ACBM) per each building assessment. This documentation shall be available to all personnel (including contractor personnel) entering the facility at their request. Corrective action was required by 400 Area Integrated Annual Appraisal/Audit for Fiscal Year 1992 (IAA-92-0007) to provide this notification documentation. No formal method had been developed to communicate the location and nature of ACBM to maintenance personnel in the Fast Flux Test Facility (FFTF) 400 Area. The scope of this Data Package Document is to locate and evaluate any ACBM found at FFTF which constitutes a baseline. This includes all buildings within the protected area. These findings are compiled from earlier reports, numerous work packages and engineering evaluations of employee findings.

  12. A novel multitarget tracking algorithm for Myosin VI protein molecules on actin filaments in TIRFM sequences.

    PubMed

    Li, G; Sanchez, V; Nagaraj, P C S B; Khan, S; Rajpoot, N

    2015-12-01

    We propose a novel multitarget tracking framework for Myosin VI protein molecules in total internal reflection fluorescence microscopy sequences which integrates an extended Hungarian algorithm with an interacting multiple model filter. The extended Hungarian algorithm, which is a linear assignment problem based method, helps to solve measurement assignment and spot association problems commonly encountered when dealing with multiple targets, although a two-motion model interacting multiple model filter increases the tracking accuracy by modelling the nonlinear dynamics of Myosin VI protein molecules on actin filaments. The evaluation of our tracking framework is conducted on both real and synthetic total internal reflection fluorescence microscopy sequences. The results show that the framework achieves higher tracking accuracies compared to the state-of-the-art tracking methods, especially for sequences with high spot density. PMID:26259144

  13. Out-of-sequence measurement updates for multi-hypothesis tracking algorithms

    NASA Astrophysics Data System (ADS)

    Chan, Stephanie; Paffenroth, Randy

    2008-04-01

    In multi-sensor tracking systems, observations are often exchanged over a network for processing. Network delays create situations in which measurements arrive out-of-sequence. The out-of-sequence measurement (OOSM) update problem is of particular significance in networked multiple hypothesis tracking (MHT) algorithms. The advantage of MHT is the ability to revoke past measurement assignment decisions as future information becomes available. Accordingly, we not only have to deal with network delays for initial assignment, but must also address delayed assignment revocations. We study the performance of extant algorithms and two algorithm modifications for the purpose of OOSM filtering in MHT architectures.

  14. A vectorized track finding and fitting algorithm in experimental high energy physics using a cyber-205

    NASA Astrophysics Data System (ADS)

    Georgiopoulos, C. H.; Goldman, J. H.; Hodous, M. F.

    1987-11-01

    We report on a fully vectorized track finding and fitting algorithm that has been used to reconstruct charged particle trajectories in a multiwire chamber system. This algorithm is currently used for data analysis of the E-711 experiment a Fermilab. The program is written for a CYBER 205 on which the average event takes 13.5 ms to process compared to 6.7 s for an optimized scalar algorithm on a VAX-11/780.

  15. "Joined up" Thinking? Unsupported "Fast-Track" Transitions in the Context of Parental Substance Use

    ERIC Educational Resources Information Center

    Wilson, Sarah; Cunningham-Burley, Sarah; Bancroft, Angus; Backett-Milburn, Kathryn

    2008-01-01

    Recent policy responses to the risks entailed in "fast-track" school-work transitions have targeted careleavers and young people identified as "not in education, employment or training" (NEET). However, this approach has been criticised as diverting attention away from the fragile circumstances of others who may receive little parental or service…

  16. New Medical-School Programs Put Students on a Fast Track to the White Coat

    ERIC Educational Resources Information Center

    Mangan, Katherine

    2009-01-01

    California's lieutenant governor has proposed a fast-track medical school that would shave three years off the training needed to become a physician. It is not the first time such an idea has been offered. The proposal, for a hoped-for medical school at the University of California at Merced, struck some medical educators as both unrealistic and…

  17. Preventing Serious Conduct Problems in School-Age Youth: The Fast Track Program

    ERIC Educational Resources Information Center

    Slough, Nancy M.; McMahon, Robert J.; Bierman, Karen L.; Coie, John D.; Dodge, Kenneth A.; Foster, E. Michael; Greenberg, Mark T.; Lochman, John E.; McMahon, Robert J.; Pinderhughes, Ellen E.

    2008-01-01

    Children with early-starting conduct problems have a very poor prognosis and exact a high cost to society. The Fast Track project is a multisite, collaborative research project investigating the efficacy of a comprehensive, long-term, multicomponent intervention designed to "prevent" the development of serious conduct problems in high-risk…

  18. The Effects of the Fast Track Preventive Intervention on the Development of Conduct Disorder across Childhood

    ERIC Educational Resources Information Center

    Child Development, 2011

    2011-01-01

    The impact of the Fast Track intervention on externalizing disorders across childhood was examined. Eight hundred-ninety-one early-starting children (69% male; 51% African American) were randomly assigned by matched sets of schools to intervention or control conditions. The 10-year intervention addressed parent behavior-management, child social…

  19. The Status of Girls' Education in Education for All Fast Track Initiative Partner Countries

    ERIC Educational Resources Information Center

    Clarke, Prema

    2011-01-01

    This viewpoint examines girls' performance in primary education in the countries that joined the Education for All Fast Track Initiative between 2002 and 2008. At the time they joined the initiative, a first group of countries (high performers) had already achieved high and equal enrollment of girls and boys. Significant progress is evident in a…

  20. Fast Track Initiative: Building a Global Compact for Education. Education Notes

    ERIC Educational Resources Information Center

    Human Development Network Education, 2005

    2005-01-01

    This note series is intended to summarize lessons learned and key policy findings on the World Bank's work in education. "Fast Track Initiative" ("FTI") was launched in 2002 as a partnership between donor and developing countries to accelerate progress towards the Millennium Development Goal (MDG) of universal primary education. "FTI" is built on…

  1. Online Tracking Algorithms on GPUs for the P̅ANDA Experiment at FAIR

    NASA Astrophysics Data System (ADS)

    Bianchi, L.; Herten, A.; Ritman, J.; Stockmanns, T.; Adinetz, A.; Kraus, J.; Pleiter, D.

    2015-12-01

    P̅ANDA is a future hadron and nuclear physics experiment at the FAIR facility in construction in Darmstadt, Germany. In contrast to the majority of current experiments, PANDA's strategy for data acquisition is based on event reconstruction from free-streaming data, performed in real time entirely by software algorithms using global detector information. This paper reports the status of the development of algorithms for the reconstruction of charged particle tracks, optimized online data processing applications, using General-Purpose Graphic Processing Units (GPU). Two algorithms for trackfinding, the Triplet Finder and the Circle Hough, are described, and details of their GPU implementations are highlighted. Average track reconstruction times of less than 100 ns are obtained running the Triplet Finder on state-of- the-art GPU cards. In addition, a proof-of-concept system for the dispatch of data to tracking algorithms using Message Queues is presented.

  2. An Efficient Lagrangean Relaxation-based Object Tracking Algorithm in Wireless Sensor Networks

    PubMed Central

    Lin, Frank Yeong-Sung; Lee, Cheng-Ta

    2010-01-01

    In this paper we propose an energy-efficient object tracking algorithm in wireless sensor networks (WSNs). Such sensor networks have to be designed to achieve energy-efficient object tracking for any given arbitrary topology. We consider in particular the bi-directional moving objects with given frequencies for each pair of sensor nodes and link transmission cost. This problem is formulated as a 0/1 integer-programming problem. A Lagrangean relaxation-based (LR-based) heuristic algorithm is proposed for solving the optimization problem. Experimental results showed that the proposed algorithm achieves near optimization in energy-efficient object tracking. Furthermore, the algorithm is very efficient and scalable in terms of the solution time. PMID:22163643

  3. A fast and memory-sparing probabilistic selection algorithm for the GPU

    SciTech Connect

    Monroe, Laura M; Wendelberger, Joanne; Michalak, Sarah

    2010-09-29

    A fast and memory-sparing probabilistic top-N selection algorithm is implemented on the GPU. This probabilistic algorithm gives a deterministic result and always terminates. The use of randomization reduces the amount of data that needs heavy processing, and so reduces both the memory requirements and the average time required for the algorithm. This algorithm is well-suited to more general parallel processors with multiple layers of memory hierarchy. Probabilistic Las Vegas algorithms of this kind are a form of stochastic optimization and can be especially useful for processors having a limited amount of fast memory available.

  4. Life in the Fast Track: How States Seek to Balance Incentives and Quality in Alternative Teacher Certification Programs

    ERIC Educational Resources Information Center

    Johnson, Susan Moore; Birkeland, Sarah E.; Peske, Heather G.

    2005-01-01

    The prospect of overseeing the rapid preparation of many participants in fast-track alternative certification programs presents several challenges for state education officials who seek to maintain, or even enhance, the quality of the state's teaching force. This study examined a range of fast-track alternative teacher certification programs in 11…

  5. Fast three-step phase-shifting algorithm

    SciTech Connect

    Huang, Peisen S.; Zhang Song

    2006-07-20

    We propose a new three-step phase-shifting algorithm, which is much faster than the traditional three-step algorithm. We achieve the speed advantage by using a simple intensity ratio function to replace the arc tangent function in the traditional algorithm. The phase error caused by this new algorithm is compensated for by use of a lookup table. Our experimental result sshow that both the new algorithm and the traditional algorithm generate similar results, but the new algorithm is 3.4 times faster. By implementing this new algorithm in a high-resolution, real-time three-dimensional shape measurement system,we were able to achieve a measurement speed of 40 frames per second ata resolution of 532x500 pixels, all with an ordinary personal computer.

  6. A Novel Validation Algorithm Allows for Automated Cell Tracking and the Extraction of Biologically Meaningful Parameters

    PubMed Central

    Madany Mamlouk, Amir; Schicktanz, Simone; Kruse, Charli

    2011-01-01

    Automated microscopy is currently the only method to non-invasively and label-free observe complex multi-cellular processes, such as cell migration, cell cycle, and cell differentiation. Extracting biological information from a time-series of micrographs requires each cell to be recognized and followed through sequential microscopic snapshots. Although recent attempts to automatize this process resulted in ever improving cell detection rates, manual identification of identical cells is still the most reliable technique. However, its tedious and subjective nature prevented tracking from becoming a standardized tool for the investigation of cell cultures. Here, we present a novel method to accomplish automated cell tracking with a reliability comparable to manual tracking. Previously, automated cell tracking could not rival the reliability of manual tracking because, in contrast to the human way of solving this task, none of the algorithms had an independent quality control mechanism; they missed validation. Thus, instead of trying to improve the cell detection or tracking rates, we proceeded from the idea to automatically inspect the tracking results and accept only those of high trustworthiness, while rejecting all other results. This validation algorithm works independently of the quality of cell detection and tracking through a systematic search for tracking errors. It is based only on very general assumptions about the spatiotemporal contiguity of cell paths. While traditional tracking often aims to yield genealogic information about single cells, the natural outcome of a validated cell tracking algorithm turns out to be a set of complete, but often unconnected cell paths, i.e. records of cells from mitosis to mitosis. This is a consequence of the fact that the validation algorithm takes complete paths as the unit of rejection/acceptance. The resulting set of complete paths can be used to automatically extract important biological parameters with high

  7. A novel validation algorithm allows for automated cell tracking and the extraction of biologically meaningful parameters.

    PubMed

    Rapoport, Daniel H; Becker, Tim; Madany Mamlouk, Amir; Schicktanz, Simone; Kruse, Charli

    2011-01-01

    Automated microscopy is currently the only method to non-invasively and label-free observe complex multi-cellular processes, such as cell migration, cell cycle, and cell differentiation. Extracting biological information from a time-series of micrographs requires each cell to be recognized and followed through sequential microscopic snapshots. Although recent attempts to automatize this process resulted in ever improving cell detection rates, manual identification of identical cells is still the most reliable technique. However, its tedious and subjective nature prevented tracking from becoming a standardized tool for the investigation of cell cultures. Here, we present a novel method to accomplish automated cell tracking with a reliability comparable to manual tracking. Previously, automated cell tracking could not rival the reliability of manual tracking because, in contrast to the human way of solving this task, none of the algorithms had an independent quality control mechanism; they missed validation. Thus, instead of trying to improve the cell detection or tracking rates, we proceeded from the idea to automatically inspect the tracking results and accept only those of high trustworthiness, while rejecting all other results. This validation algorithm works independently of the quality of cell detection and tracking through a systematic search for tracking errors. It is based only on very general assumptions about the spatiotemporal contiguity of cell paths. While traditional tracking often aims to yield genealogic information about single cells, the natural outcome of a validated cell tracking algorithm turns out to be a set of complete, but often unconnected cell paths, i.e. records of cells from mitosis to mitosis. This is a consequence of the fact that the validation algorithm takes complete paths as the unit of rejection/acceptance. The resulting set of complete paths can be used to automatically extract important biological parameters with high

  8. Ballistic target tracking algorithm based on improved particle filtering

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  9. Vision-based measurement for rotational speed by improving Lucas-Kanade template tracking algorithm.

    PubMed

    Guo, Jie; Zhu, Chang'an; Lu, Siliang; Zhang, Dashan; Zhang, Chunyu

    2016-09-01

    Rotational angle and speed are important parameters for condition monitoring and fault diagnosis of rotating machineries, and their measurement is useful in precision machining and early warning of faults. In this study, a novel vision-based measurement algorithm is proposed to complete this task. A high-speed camera is first used to capture the video of the rotational object. To extract the rotational angle, the template-based Lucas-Kanade algorithm is introduced to complete motion tracking by aligning the template image in the video sequence. Given the special case of nonplanar surface of the cylinder object, a nonlinear transformation is designed for modeling the rotation tracking. In spite of the unconventional and complex form, the transformation can realize angle extraction concisely with only one parameter. A simulation is then conducted to verify the tracking effect, and a practical tracking strategy is further proposed to track consecutively the video sequence. Based on the proposed algorithm, instantaneous rotational speed (IRS) can be measured accurately and efficiently. Finally, the effectiveness of the proposed algorithm is verified on a brushless direct current motor test rig through the comparison with results obtained by the microphone. Experimental results demonstrate that the proposed algorithm can extract accurately rotational angles and can measure IRS with the advantage of noncontact and effectiveness. PMID:27607300

  10. Fast neutrons detection in CR-39 and DAM-ADC nuclear track detectors

    NASA Astrophysics Data System (ADS)

    Abdalla, A. M.; Ashraf, O.; Rammah, Y. S.; Ashry, A. H.; Eisa, M.; Tsuruta, T.

    2015-03-01

    Fast detection of neutrons in CR-39 and DAM-ADC nuclear track detectors were investigated using new etching conditions. The neutron irradiation is performed using a 5 mCi Am-Be source present at the National Institute of Standards (NIS) of Egypt. Using the new etching condition, irradiated CR-39 samples were etched for 4 h and DAM-ADC samples for 80 min. Suitable analyzing software has been used to analyze experimental data.The dependence of neutrons track density on the neutrons fluence is investigated. When etched under optimum conditions, the relationship between track density and fluence is determined which is found to be linear. Detection efficiency has been represented for both SSNTDs and found to be constant with fluence, which reflects the importance of using CR-39 and DAM-ADC detectors in the field of neutron dosimetry. Linear relationship between track density and effective dose is determined.

  11. Lightning Jump Algorithm and Relation to Thunderstorm Cell Tracking, GLM Proxy and Other Meteorological Measurements

    NASA Technical Reports Server (NTRS)

    Schultz, Christopher J.; Carey, Lawrence D.; Cecil, Daniel J.; Bateman, Monte

    2012-01-01

    The lightning jump algorithm has a robust history in correlating upward trends in lightning to severe and hazardous weather occurrence. The algorithm uses the correlation between the physical principles that govern an updraft's ability to produce microphysical and kinematic conditions conducive for electrification and its role in the development of severe weather conditions. Recent work has demonstrated that the lightning jump algorithm concept holds significant promise in the operational realm, aiding in the identification of thunderstorms that have potential to produce severe or hazardous weather. However, a large amount of work still needs to be completed in spite of these positive results. The total lightning jump algorithm is not a stand-alone concept that can be used independent of other meteorological measurements, parameters, and techniques. For example, the algorithm is highly dependent upon thunderstorm tracking to build lightning histories on convective cells. Current tracking methods show that thunderstorm cell tracking is most reliable and cell histories are most accurate when radar information is incorporated with lightning data. In the absence of radar data, the cell tracking is a bit less reliable but the value added by the lightning information is much greater. For optimal application, the algorithm should be integrated with other measurements that assess storm scale properties (e.g., satellite, radar). Therefore, the recent focus of this research effort has been assessing the lightning jump's relation to thunderstorm tracking, meteorological parameters, and its potential uses in operational meteorology. Furthermore, the algorithm must be tailored for the optically-based GOES-R Geostationary Lightning Mapper (GLM), as what has been observed using Very High Frequency Lightning Mapping Array (VHF LMA) measurements will not exactly translate to what will be observed by GLM due to resolution and other instrument differences. Herein, we present some of

  12. A fast portable implementation of the Secure Hash Algorithm, III.

    SciTech Connect

    McCurley, Kevin S.

    1992-10-01

    In 1992, NIST announced a proposed standard for a collision-free hash function. The algorithm for producing the hash value is known as the Secure Hash Algorithm (SHA), and the standard using the algorithm in known as the Secure Hash Standard (SHS). Later, an announcement was made that a scientist at NSA had discovered a weakness in the original algorithm. A revision to this standard was then announced as FIPS 180-1, and includes a slight change to the algorithm that eliminates the weakness. This new algorithm is called SHA-1. In this report we describe a portable and efficient implementation of SHA-1 in the C language. Performance information is given, as well as tips for porting the code to other architectures. We conclude with some observations on the efficiency of the algorithm, and a discussion of how the efficiency of SHA might be improved.

  13. The new approach for infrared target tracking based on the particle filter algorithm

    NASA Astrophysics Data System (ADS)

    Sun, Hang; Han, Hong-xia

    2011-08-01

    Target tracking on the complex background in the infrared image sequence is hot research field. It provides the important basis in some fields such as video monitoring, precision, and video compression human-computer interaction. As a typical algorithms in the target tracking framework based on filtering and data connection, the particle filter with non-parameter estimation characteristic have ability to deal with nonlinear and non-Gaussian problems so it were widely used. There are various forms of density in the particle filter algorithm to make it valid when target occlusion occurred or recover tracking back from failure in track procedure, but in order to capture the change of the state space, it need a certain amount of particles to ensure samples is enough, and this number will increase in accompany with dimension and increase exponentially, this led to the increased amount of calculation is presented. In this paper particle filter algorithm and the Mean shift will be combined. Aiming at deficiencies of the classic mean shift Tracking algorithm easily trapped into local minima and Unable to get global optimal under the complex background. From these two perspectives that "adaptive multiple information fusion" and "with particle filter framework combining", we expand the classic Mean Shift tracking framework .Based on the previous perspective, we proposed an improved Mean Shift infrared target tracking algorithm based on multiple information fusion. In the analysis of the infrared characteristics of target basis, Algorithm firstly extracted target gray and edge character and Proposed to guide the above two characteristics by the moving of the target information thus we can get new sports guide grayscale characteristics and motion guide border feature. Then proposes a new adaptive fusion mechanism, used these two new information adaptive to integrate into the Mean Shift tracking framework. Finally we designed a kind of automatic target model updating strategy

  14. Data Association and Bullet Tracking Algorithms for the Fight Sight Experiment

    SciTech Connect

    Breitfeller, E; Roberts, R

    2005-10-07

    Previous LLNL investigators developed a bullet and projectile tracking system over a decade ago. Renewed interest in the technology has spawned research that culminated in a live-fire experiment, called Fight Sight, in September 2005. The experiment was more complex than previous LLNL bullet tracking experiments in that it included multiple shooters with simultaneous fire, new sensor-shooter geometries, large amounts of optical clutter, and greatly increased sensor-shooter distances. This presentation describes the data association and tracking algorithms for the Fight Sight experiment. Image processing applied to the imagery yields a sequence of bullet features which are input to a data association routine. The data association routine matches features with existing tracks, or initializes new tracks as needed. A Kalman filter is used to smooth and extrapolate existing tracks. The Kalman filter is also used to back-track bullets to their point of origin, thereby revealing the location of the shooter. It also provides an error ellipse for each shooter, quantifying the uncertainty of shooter location. In addition to describing the data association and tracking algorithms, several examples from the Fight Sight experiment are also presented.

  15. Recent numerical and algorithmic advances within the volume tracking framework for modeling interfacial flows

    SciTech Connect

    François, Marianne M.

    2015-05-28

    A review of recent advances made in numerical methods and algorithms within the volume tracking framework is presented. The volume tracking method, also known as the volume-of-fluid method has become an established numerical approach to model and simulate interfacial flows. Its advantage is its strict mass conservation. However, because the interface is not explicitly tracked but captured via the material volume fraction on a fixed mesh, accurate estimation of the interface position, its geometric properties and modeling of interfacial physics in the volume tracking framework remain difficult. Several improvements have been made over the last decade to address these challenges. In this study, the multimaterial interface reconstruction method via power diagram, curvature estimation via heights and mean values and the balanced-force algorithm for surface tension are highlighted.

  16. Recent numerical and algorithmic advances within the volume tracking framework for modeling interfacial flows

    DOE PAGESBeta

    François, Marianne M.

    2015-05-28

    A review of recent advances made in numerical methods and algorithms within the volume tracking framework is presented. The volume tracking method, also known as the volume-of-fluid method has become an established numerical approach to model and simulate interfacial flows. Its advantage is its strict mass conservation. However, because the interface is not explicitly tracked but captured via the material volume fraction on a fixed mesh, accurate estimation of the interface position, its geometric properties and modeling of interfacial physics in the volume tracking framework remain difficult. Several improvements have been made over the last decade to address these challenges.more » In this study, the multimaterial interface reconstruction method via power diagram, curvature estimation via heights and mean values and the balanced-force algorithm for surface tension are highlighted.« less

  17. Fast TPC Online Tracking on GPUs and Asynchronous Data Processing in the ALICE HLT to facilitate Online Calibration

    NASA Astrophysics Data System (ADS)

    Rohr, David; Gorbunov, Sergey; Krzewicki, Mikolaj; Breitner, Timo; Kretz, Matthias; Lindenstruth, Volker

    2015-12-01

    ALICE (A Large Heavy Ion Experiment) is one of the four major experiments at the Large Hadron Collider (LHC) at CERN, which is today the most powerful particle accelerator worldwide. The High Level Trigger (HLT) is an online compute farm of about 200 nodes, which reconstructs events measured by the ALICE detector in real-time. The HLT uses a custom online data-transport framework to distribute data and workload among the compute nodes. ALICE employs several calibration-sensitive subdetectors, e.g. the TPC (Time Projection Chamber). For a precise reconstruction, the HLT has to perform the calibration online. Online- calibration can make certain Offline calibration steps obsolete and can thus speed up Offline analysis. Looking forward to ALICE Run III starting in 2020, online calibration becomes a necessity. The main detector used for track reconstruction is the TPC. Reconstructing the trajectories in the TPC is the most compute-intense step during event reconstruction. Therefore, a fast tracking implementation is of great importance. Reconstructed TPC tracks build the basis for the calibration making a fast online-tracking mandatory. We present several components developed for the ALICE High Level Trigger to perform fast event reconstruction and to provide features required for online calibration. As first topic, we present our TPC tracker, which employs GPUs to speed up the processing, and which bases on a Cellular Automaton and on the Kalman filter. Our TPC tracking algorithm has been successfully used in 2011 and 2012 in the lead-lead and the proton-lead runs. We have improved it to leverage features of newer GPUs and we have ported it to support OpenCL, CUDA, and CPUs with a single common source code. This makes us vendor independent. As second topic, we present framework extensions required for online calibration. The extensions, however, are generic and can be used for other purposes as well. We have extended the framework to support asynchronous compute

  18. Determining the bias and variance of a deterministic finger-tracking algorithm.

    PubMed

    Morash, Valerie S; van der Velden, Bas H M

    2016-06-01

    Finger tracking has the potential to expand haptic research and applications, as eye tracking has done in vision research. In research applications, it is desirable to know the bias and variance associated with a finger-tracking method. However, assessing the bias and variance of a deterministic method is not straightforward. Multiple measurements of the same finger position data will not produce different results, implying zero variance. Here, we present a method of assessing deterministic finger-tracking variance and bias through comparison to a non-deterministic measure. A proof-of-concept is presented using a video-based finger-tracking algorithm developed for the specific purpose of tracking participant fingers during a psychological research study. The algorithm uses ridge detection on videos of the participant's hand, and estimates the location of the right index fingertip. The algorithm was evaluated using data from four participants, who explored tactile maps using only their right index finger and all right-hand fingers. The algorithm identified the index fingertip in 99.78 % of one-finger video frames and 97.55 % of five-finger video frames. Although the algorithm produced slightly biased and more dispersed estimates relative to a human coder, these differences (x=0.08 cm, y=0.04 cm) and standard deviations (σ x =0.16 cm, σ y =0.21 cm) were small compared to the size of a fingertip (1.5-2.0 cm). Some example finger-tracking results are provided where corrections are made using the bias and variance estimates. PMID:26174712

  19. The implementation of an automated tracking algorithm for the track detection of migratory anticyclones affecting the Mediterranean

    NASA Astrophysics Data System (ADS)

    Hatzaki, Maria; Flocas, Elena A.; Simmonds, Ian; Kouroutzoglou, John; Keay, Kevin; Rudeva, Irina

    2013-04-01

    Migratory cyclones and anticyclones mainly account for the short-term weather variations in extra-tropical regions. By contrast to cyclones that have drawn major scientific attention due to their direct link to active weather and precipitation, climatological studies on anticyclones are limited, even though they also are associated with extreme weather phenomena and play an important role in global and regional climate. This is especially true for the Mediterranean, a region particularly vulnerable to climate change, and the little research which has been done is essentially confined to the manual analysis of synoptic charts. For the construction of a comprehensive climatology of migratory anticyclonic systems in the Mediterranean using an objective methodology, the Melbourne University automatic tracking algorithm is applied, based to the ERA-Interim reanalysis mean sea level pressure database. The algorithm's reliability in accurately capturing the weather patterns and synoptic climatology of the transient activity has been widely proven. This algorithm has been extensively applied for cyclone studies worldwide and it has been also successfully applied for the Mediterranean, though its use for anticyclone tracking is limited to the Southern Hemisphere. In this study the performance of the tracking algorithm under different data resolutions and different choices of parameter settings in the scheme is examined. Our focus is on the appropriate modification of the algorithm in order to efficiently capture the individual characteristics of the anticyclonic tracks in the Mediterranean, a closed basin with complex topography. We show that the number of the detected anticyclonic centers and the resulting tracks largely depend upon the data resolution and the search radius. We also find that different scale anticyclones and secondary centers that lie within larger anticyclone structures can be adequately represented; this is important, since the extensions of major

  20. Fast algorithm for detecting community structure in networks

    NASA Astrophysics Data System (ADS)

    Newman, M. E.

    2004-06-01

    Many networks display community structure—groups of vertices within which connections are dense but between which they are sparser—and sensitive computer algorithms have in recent years been developed for detecting this structure. These algorithms, however, are computationally demanding, which limits their application to small networks. Here we describe an algorithm which gives excellent results when tested on both computer-generated and real-world networks and is much faster, typically thousands of times faster, than previous algorithms. We give several example applications, including one to a collaboration network of more than 50 000 physicists.

  1. Algorithm For Simplified Robotic Tracking Of Weld Seams

    NASA Technical Reports Server (NTRS)

    Gutow, David A.; Paternoster, Vincent Y.

    1992-01-01

    Algorithm computes small cross-seam corrections to programmed path of welding robot. Intended for use with add-on vision system loosely coupled to robot, transmitting small amount of information about weld seam ahead of torch. Position of welding torch in reference frame of moving window estimated on basis of data on weld seam and speed of torch. Does not need data on position of torch, and does not transform data on seam to another reference frame.

  2. A fast algorithm for reconstruction of spectrally sparse signals in super-resolution

    NASA Astrophysics Data System (ADS)

    Cai, Jian-Feng; Liu, Suhui; Xu, Weiyu

    2015-08-01

    We propose a fast algorithm to reconstruct spectrally sparse signals from a small number of randomly observed time domain samples. Different from conventional compressed sensing where frequencies are discretized, we consider the super-resolution case where the frequencies can be any values in the normalized continuous frequency domain [0; 1). We first convert our signal recovery problem into a low rank Hankel matrix completion problem, for which we then propose an efficient feasible point algorithm named projected Wirtinger gradient algorithm(PWGA). The algorithm can be further accelerated by a scheme inspired by the fast iterative shrinkage-thresholding algorithm (FISTA). Numerical experiments are provided to illustrate the effectiveness of our proposed algorithm. Different from earlier approaches, our algorithm can solve problems of large scale efficiently.

  3. Fast Optimal Load Balancing Algorithms for 1D Partitioning

    SciTech Connect

    Pinar, Ali; Aykanat, Cevdet

    2002-12-09

    One-dimensional decomposition of nonuniform workload arrays for optimal load balancing is investigated. The problem has been studied in the literature as ''chains-on-chains partitioning'' problem. Despite extensive research efforts, heuristics are still used in parallel computing community with the ''hope'' of good decompositions and the ''myth'' of exact algorithms being hard to implement and not runtime efficient. The main objective of this paper is to show that using exact algorithms instead of heuristics yields significant load balance improvements with negligible increase in preprocessing time. We provide detailed pseudocodes of our algorithms so that our results can be easily reproduced. We start with a review of literature on chains-on-chains partitioning problem. We propose improvements on these algorithms as well as efficient implementation tips. We also introduce novel algorithms, which are asymptotically and runtime efficient. We experimented with data sets from two different applications: Sparse matrix computations and Direct volume rendering. Experiments showed that the proposed algorithms are 100 times faster than a single sparse-matrix vector multiplication for 64-way decompositions on average. Experiments also verify that load balance can be significantly improved by using exact algorithms instead of heuristics. These two findings show that exact algorithms with efficient implementations discussed in this paper can effectively replace heuristics.

  4. Context exploitation in intelligence, surveillance, and reconnaissance for detection and tracking algorithms

    NASA Astrophysics Data System (ADS)

    Tucker, Jonathan D.; Stanfill, S. Robert

    2015-05-01

    Intelligence, Surveillance, and Reconnaissance (ISR) missions involve complex analysis of sensor data that can benefit from the exploitation of geographically aligned context. In this paper we discuss our approach to utilizing geo-registered imagery and context for the purpose of aiding ISR detection and tracking applications. Specifically this includes rendering context masks on imagery, increasing the speed at which detection algorithms process data, providing a way to intelligently control detection density for given ground areas, identifying difficult traffic terrain, refining peak suppression for congested areas, reducing target center of mass location errors, and increasing track coverage and duration through track prediction error robustness.

  5. A fast and convergent stochastic MLP learning algorithm.

    PubMed

    Sakurai, A

    2001-12-01

    We propose a stochastic learning algorithm for multilayer perceptrons of linear-threshold function units, which theoretically converges with probability one and experimentally exhibits 100% convergence rate and remarkable speed on parity and classification problems with typical generalization accuracy. For learning the n bit parity function with n hidden units, the algorithm converged on all the trials we tested (n=2 to 12) after 5.8 x 4.1(n) presentations for 0.23 x 4.0(n-6) seconds on a 533MHz Alpha 21164A chip on average, which is five to ten times faster than Levenberg-Marquardt algorithm with restarts. For a medium size classification problem known as Thyroid in UCI repository, the algorithm is faster in speed and comparative in generalization accuracy than the standard backpropagation and Levenberg-Marquardt algorithms. PMID:11852440

  6. Improving GPU-accelerated adaptive IDW interpolation algorithm using fast kNN search.

    PubMed

    Mei, Gang; Xu, Nengxiong; Xu, Liangliang

    2016-01-01

    This paper presents an efficient parallel Adaptive Inverse Distance Weighting (AIDW) interpolation algorithm on modern Graphics Processing Unit (GPU). The presented algorithm is an improvement of our previous GPU-accelerated AIDW algorithm by adopting fast k-nearest neighbors (kNN) search. In AIDW, it needs to find several nearest neighboring data points for each interpolated point to adaptively determine the power parameter; and then the desired prediction value of the interpolated point is obtained by weighted interpolating using the power parameter. In this work, we develop a fast kNN search approach based on the space-partitioning data structure, even grid, to improve the previous GPU-accelerated AIDW algorithm. The improved algorithm is composed of the stages of kNN search and weighted interpolating. To evaluate the performance of the improved algorithm, we perform five groups of experimental tests. The experimental results indicate: (1) the improved algorithm can achieve a speedup of up to 1017 over the corresponding serial algorithm; (2) the improved algorithm is at least two times faster than our previous GPU-accelerated AIDW algorithm; and (3) the utilization of fast kNN search can significantly improve the computational efficiency of the entire GPU-accelerated AIDW algorithm. PMID:27610308

  7. Low-Complexity Saliency Detection Algorithm for Fast Perceptual Video Coding

    PubMed Central

    Liu, Pengyu; Jia, Kebin

    2013-01-01

    A low-complexity saliency detection algorithm for perceptual video coding is proposed; low-level encoding information is adopted as the characteristics of visual perception analysis. Firstly, this algorithm employs motion vector (MV) to extract temporal saliency region through fast MV noise filtering and translational MV checking procedure. Secondly, spatial saliency region is detected based on optimal prediction mode distributions in I-frame and P-frame. Then, it combines the spatiotemporal saliency detection results to define the video region of interest (VROI). The simulation results validate that the proposed algorithm can avoid a large amount of computation work in the visual perception characteristics analysis processing compared with other existing algorithms; it also has better performance in saliency detection for videos and can realize fast saliency detection. It can be used as a part of the video standard codec at medium-to-low bit-rates or combined with other algorithms in fast video coding. PMID:24489495

  8. How Does the Fast Track Intervention Prevent Adverse Outcomes in Young Adulthood?

    PubMed

    Sorensen, Lucy C; Dodge, Kenneth A

    2016-03-01

    Numerous studies have shown that childhood interventions can foster improved outcomes in adulthood. Less well understood is precisely how-that is, through which developmental pathways-these interventions work. This study assesses mechanisms by which the Fast Track project (n = 891), a randomized intervention in the early 1990s for high-risk children in four communities (Durham, NC; Nashville, TN; rural PA; and Seattle, WA), reduced delinquency, arrests, and general and mental health service utilization in adolescence through young adulthood (ages 12-20). A decomposition of treatment effects indicates that about a third of Fast Track's impact on later crime outcomes can be accounted for by improvements in social and self-regulation skills during childhood (ages 6-11), such as prosocial behavior, emotion regulation, and problem solving. These skills proved less valuable for the prevention of general and mental health problems. PMID:26670938

  9. Preventing Serious Conduct Problems in School-Age Youths: The Fast Track Program

    PubMed Central

    Slough, Nancy M.; McMahon, Robert J.; Bierman, Karen L.; Coie, John D.; Dodge, Kenneth A.; Foster, E. Michael; Greenberg, Mark T.; Lochman, John E.; McMahon, Robert J.; Pinderhughes, Ellen E.

    2009-01-01

    Children with early-starting conduct Problems have a very poor prognosis and exact a high cost to society. The Fast Track project is a multisite, collaborative research project investigating the efficacy of a comprehensive, long-term, multicomponent intervention designed to prevent the development of serious conduct problems in high-risk children. In this article, we (a) provide an overview of the development model that serves as the conceptual foundation for the Fast Track intervention and describe its integration into the intervention model; (b) outline the research design and intervention model, with an emphasis on the elementary school phase of the intervention; and (c) summarize findings to dale concerning intervention outcomes. We then provide a case illustration, and conclude with a discussion of guidelines for practitioners who work with children with conduct problems. PMID:19890487

  10. Developmental Mediation of Genetic Variation in Response to the Fast Track Prevention Program

    PubMed Central

    Albert, Dustin; Belsky, Daniel W.; Crowley, D. Max; Bates, John E.; Pettit, Gregory S.; Lansford, Jennifer E.; Dick, Danielle; Dodge, Kenneth A.

    2015-01-01

    We conducted a developmental analysis of genetic moderation of the effect of the Fast Track intervention on adult externalizing psychopathology. The Fast Track intervention enrolled 891 children at high risk to develop externalizing behavior problems when they were in kindergarten. Half of the enrolled children were randomly assigned to receive 10 years of treatment with a range of services and resources provided to the children and their families and the other half to usual care (controls). We previously showed that the effect of the Fast Track intervention on participants’ risk of externalizing psychopathology at age 25 years was moderated by a variant in the Glucocorticoid Receptor Gene (NR3C1). Children who carried copies of the A-allele of the single-nucleotide polymorphism rs10482672 had the highest risk of externalizing psychopathology if they were in the control arm of the trial and the lowest risk of externalizing psychopathology if they were in the treatment arm. In this study, we test a developmental hypothesis about the origins of this for-better-and-for-worse gene-by-intervention interaction (GxI): That the observed GxI effect on adult psychopathology is mediated by the proximal impact of intervention on childhood externalizing problems and adolescent substance use and delinquency. We analyzed longitudinal data tracking the 270 European-American children in the Fast Track RCT with available genetic information (129 intervention children and 141 control-group peers, 69% male) from kindergarten through age 25 years. Results show that the same pattern of “for-better-and-for-worse” susceptibility to intervention observed at the age-25 follow-up was evident already during childhood. At the elementary school follow-ups and at the middle/high-school follow-ups, rs10482672 predicted better adjustment among children receiving the Fast Track intervention, and worse adjustment among children in the control condition. In turn, these proximal GxI effects

  11. TRACC: Algorithm for Predicting and Tracking Barges on Inland Waterways

    Energy Science and Technology Software Center (ESTSC)

    2010-04-23

    Algorithm developed in this work is used to predict the location and estimate the traveling speed of a barge moving in inland waterway network. Measurements obtained from GPS or other systems are corrupted with measurement noise and reported at large, irregular time intervals. Thus, creating uncertainty about the current location of the barge and minimizing the effectiveness of emergency response activities in case of an accident or act of terrorism. Developing a prediction algorithm becomemore » a non-trivial problem due to estimation of speed becomes challenging, attributed to the complex interactions between multiple systems associated in the process. This software, uses systems approach in modeling the motion dynamics of the barge and estimates the location and speed of the barge at next, user defined, time interval. In this work, first, to estimate the speed a non-linear, stochastic modeling technique was developed that take local variations and interactions existing in the system. Output speed is then used as an observation in a statistically optimal filtering technique, Kalman filter, formulated in state-space to minimize numerous errors observed in the system. The combined system synergistically fuses the local information available with measurements obtained to predict the location and speed of traveling of the barge accurately.« less

  12. TRACC: Algorithm for Predicting and Tracking Barges on Inland Waterways

    SciTech Connect

    Randeniya, Duminda I.B.

    2010-04-23

    Algorithm developed in this work is used to predict the location and estimate the traveling speed of a barge moving in inland waterway network. Measurements obtained from GPS or other systems are corrupted with measurement noise and reported at large, irregular time intervals. Thus, creating uncertainty about the current location of the barge and minimizing the effectiveness of emergency response activities in case of an accident or act of terrorism. Developing a prediction algorithm become a non-trivial problem due to estimation of speed becomes challenging, attributed to the complex interactions between multiple systems associated in the process. This software, uses systems approach in modeling the motion dynamics of the barge and estimates the location and speed of the barge at next, user defined, time interval. In this work, first, to estimate the speed a non-linear, stochastic modeling technique was developed that take local variations and interactions existing in the system. Output speed is then used as an observation in a statistically optimal filtering technique, Kalman filter, formulated in state-space to minimize numerous errors observed in the system. The combined system synergistically fuses the local information available with measurements obtained to predict the location and speed of traveling of the barge accurately.

  13. A fast track path improves access to palliative care for people with learning disabilities.

    PubMed

    Whitington, Jane; Ma, Peng

    People with learning disabilities often experience inequalities in accessing general health services. This group, their families and carers need access to effective palliative care when facing a life limiting illness. This article describes the development and implementation of a fast track referral pathway for people with learning disabilities at St Francis Hospice in Essex. Our aim is to share this pathway so others can replicate the collaborative working to improve access to palliative care services for this group. PMID:20514883

  14. FAST: A fully asynchronous and status-tracking pattern for geoprocessing services orchestration

    NASA Astrophysics Data System (ADS)

    Wu, Huayi; You, Lan; Gui, Zhipeng; Gao, Shuang; Li, Zhenqiang; Yu, Jingmin

    2014-09-01

    Geoprocessing service orchestration (GSO) provides a unified and flexible way to implement cross-application, long-lived, and multi-step geoprocessing service workflows by coordinating geoprocessing services collaboratively. Usually, geoprocessing services and geoprocessing service workflows are data and/or computing intensive. The intensity feature may make the execution process of a workflow time-consuming. Since it initials an execution request without blocking other interactions on the client side, an asynchronous mechanism is especially appropriate for GSO workflows. Many critical problems remain to be solved in existing asynchronous patterns for GSO including difficulties in improving performance, status tracking, and clarifying the workflow structure. These problems are a challenge when orchestrating performance efficiency, making statuses instantly available, and constructing clearly structured GSO workflows. A Fully Asynchronous and Status-Tracking (FAST) pattern that adopts asynchronous interactions throughout the whole communication tier of a workflow is proposed for GSO. The proposed FAST pattern includes a mechanism that actively pushes the latest status to clients instantly and economically. An independent proxy was designed to isolate the status tracking logic from the geoprocessing business logic, which assists the formation of a clear GSO workflow structure. A workflow was implemented in the FAST pattern to simulate the flooding process in the Poyang Lake region. Experimental results show that the proposed FAST pattern can efficiently tackle data/computing intensive geoprocessing tasks. The performance of all collaborative partners was improved due to the asynchronous mechanism throughout communication tier. A status-tracking mechanism helps users retrieve the latest running status of a GSO workflow in an efficient and instant way. The clear structure of the GSO workflow lowers the barriers for geospatial domain experts and model designers to

  15. Nurse initiated thrombolysis in the accident and emergency department: safe, accurate, and faster than fast track

    PubMed Central

    Heath, S; Bain, R; Andrews, A; Chida, S; Kitchen, S; Walters, M

    2003-01-01

    Objective: To reduce the time between arrival at hospital of a patient with acute myocardial infarction and administration of thrombolytic therapy (door to needle time) by the introduction of nurse initiated thrombolysis in the accident and emergency department. Methods: Two acute chest pain nurse specialists (ACPNS) based in A&E for 62.5 hours of the week were responsible for initiating thrombolysis in the A&E department. The service reverts to a "fast track" system outside of these hours, with the on call medical team prescribing thrombolysis on the coronary care unit. Prospectively gathered data were analysed for a nine month period and a head to head comparison made between the mean and median door to needle times for both systems of thrombolysis delivery. Results: Data from 91 patients were analysed; 43 (47%) were thrombolysed in A&E by the ACPNS and 48 (53%) were thrombolysed in the coronary care unit by the on call medical team. The ACPNS achieved a median door to needle time of 23 minutes (IQR=17 to 32) compared with 56 minutes (IQR=34 to 79.5) for the fast track. The proportion of patients thrombolysed in 30 minutes by the ACPNS and fast track system was 72% (31 of 43) and 21% (10 of 48) respectively (difference=51%, 95% confidence intervals 34% to 69%, p<0.05). Conclusion: Diagnosis of acute myocardial infarction and administration of thrombolysis by experienced cardiology nurses in A&E is a safe and effective strategy for reducing door to needle times, even when compared with a conventional fast track system. PMID:12954678

  16. Transformed Governance and the Education for All-Fast Track Initiative. Policy Brief 2010-02

    ERIC Educational Resources Information Center

    Gartner, David

    2010-01-01

    The Education for All-Fast Track Initiative (FTI) grew out of the "New Focus on Education for All" communique of the G-8 when Canada hosted the summit in 2002 at Kananaskis. As Canada prepares again to host the G-8, and Korea assumes leadership of the newly-empowered G-20, it is a valuable moment to revisit and re-think the current global…

  17. Fast left ventricle tracking in CMR images using localized anatomical affine optical flow

    NASA Astrophysics Data System (ADS)

    Queirós, Sandro; Vilaça, João. L.; Morais, Pedro; Fonseca, Jaime C.; D'hooge, Jan; Barbosa, Daniel

    2015-03-01

    In daily cardiology practice, assessment of left ventricular (LV) global function using non-invasive imaging remains central for the diagnosis and follow-up of patients with cardiovascular diseases. Despite the different methodologies currently accessible for LV segmentation in cardiac magnetic resonance (CMR) images, a fast and complete LV delineation is still limitedly available for routine use. In this study, a localized anatomically constrained affine optical flow method is proposed for fast and automatic LV tracking throughout the full cardiac cycle in short-axis CMR images. Starting from an automatically delineated LV in the end-diastolic frame, the endocardial and epicardial boundaries are propagated by estimating the motion between adjacent cardiac phases using optical flow. In order to reduce the computational burden, the motion is only estimated in an anatomical region of interest around the tracked boundaries and subsequently integrated into a local affine motion model. Such localized estimation enables to capture complex motion patterns, while still being spatially consistent. The method was validated on 45 CMR datasets taken from the 2009 MICCAI LV segmentation challenge. The proposed approach proved to be robust and efficient, with an average distance error of 2.1 mm and a correlation with reference ejection fraction of 0.98 (1.9 +/- 4.5%). Moreover, it showed to be fast, taking 5 seconds for the tracking of a full 4D dataset (30 ms per image). Overall, a novel fast, robust and accurate LV tracking methodology was proposed, enabling accurate assessment of relevant global function cardiac indices, such as volumes and ejection fraction

  18. Development of Fast Algorithms Using Recursion, Nesting and Iterations for Computational Electromagnetics

    NASA Technical Reports Server (NTRS)

    Chew, W. C.; Song, J. M.; Lu, C. C.; Weedon, W. H.

    1995-01-01

    In the first phase of our work, we have concentrated on laying the foundation to develop fast algorithms, including the use of recursive structure like the recursive aggregate interaction matrix algorithm (RAIMA), the nested equivalence principle algorithm (NEPAL), the ray-propagation fast multipole algorithm (RPFMA), and the multi-level fast multipole algorithm (MLFMA). We have also investigated the use of curvilinear patches to build a basic method of moments code where these acceleration techniques can be used later. In the second phase, which is mainly reported on here, we have concentrated on implementing three-dimensional NEPAL on a massively parallel machine, the Connection Machine CM-5, and have been able to obtain some 3D scattering results. In order to understand the parallelization of codes on the Connection Machine, we have also studied the parallelization of 3D finite-difference time-domain (FDTD) code with PML material absorbing boundary condition (ABC). We found that simple algorithms like the FDTD with material ABC can be parallelized very well allowing us to solve within a minute a problem of over a million nodes. In addition, we have studied the use of the fast multipole method and the ray-propagation fast multipole algorithm to expedite matrix-vector multiplication in a conjugate-gradient solution to integral equations of scattering. We find that these methods are faster than LU decomposition for one incident angle, but are slower than LU decomposition when many incident angles are needed as in the monostatic RCS calculations.

  19. Tracking lung tumour motion using a dynamically weighted optical flow algorithm and electronic portal imaging device

    NASA Astrophysics Data System (ADS)

    Teo, P. T.; Crow, R.; Van Nest, S.; Sasaki, D.; Pistorius, S.

    2013-07-01

    This paper investigates the feasibility and accuracy of using a computer vision algorithm and electronic portal images to track the motion of a tumour-like target from a breathing phantom. A multi-resolution optical flow algorithm that incorporates weighting based on the differences between frames was used to obtain a set of vectors corresponding to the motion between two frames. A global value representing the average motion was obtained by computing the average weighted mean from the set of vectors. The tracking accuracy of the optical flow algorithm as a function of the breathing rate and target visibility was investigated. Synthetic images with different contrast-to-noise ratios (CNR) were created, and motions were tracked. The accuracy of the proposed algorithm was compared against potentiometer measurements giving average position errors of 0.6 ± 0.2 mm, 0.2 ± 0.2 mm and 0.1 ± 0.1 mm with average velocity errors of 0.2 ± 0.2 mm s-1, 0.4 ± 0.3 mm s-1 and 0.6 ± 0.5 mm s-1 for 6, 12 and 16 breaths min-1 motions, respectively. The cumulative average position error reduces more rapidly with the greater number of breathing cycles present in higher breathing rates. As the CNR increases from 4.27 to 5.6, the average relative error approaches zero and the errors are less dependent on the velocity. When tracking a tumour on a patient's digitally reconstructed radiograph images, a high correlation was obtained between the dynamically weighted optical flow algorithm, a manual delineation process and a centroid tracking algorithm. While the accuracy of our approach is similar to that of other methods, the benefits are that it does not require manual delineation of the target and can therefore provide accurate real-time motion estimation during treatment.

  20. Vectorized Rebinning Algorithm for Fast Data Down-Sampling

    NASA Technical Reports Server (NTRS)

    Dean, Bruce; Aronstein, David; Smith, Jeffrey

    2013-01-01

    A vectorized rebinning (down-sampling) algorithm, applicable to N-dimensional data sets, has been developed that offers a significant reduction in computer run time when compared to conventional rebinning algorithms. For clarity, a two-dimensional version of the algorithm is discussed to illustrate some specific details of the algorithm content, and using the language of image processing, 2D data will be referred to as "images," and each value in an image as a "pixel." The new approach is fully vectorized, i.e., the down-sampling procedure is done as a single step over all image rows, and then as a single step over all image columns. Data rebinning (or down-sampling) is a procedure that uses a discretely sampled N-dimensional data set to create a representation of the same data, but with fewer discrete samples. Such data down-sampling is fundamental to digital signal processing, e.g., for data compression applications.

  1. A fast recursive algorithm for molecular dynamics simulation

    NASA Technical Reports Server (NTRS)

    Jain, A.; Vaidehi, N.; Rodriguez, G.

    1993-01-01

    The present recursive algorithm for solving molecular systems' dynamical equations of motion employs internal variable models that reduce such simulations' computation time by an order of magnitude, relative to Cartesian models. Extensive use is made of spatial operator methods recently developed for analysis and simulation of the dynamics of multibody systems. A factor-of-450 speedup over the conventional O(N-cubed) algorithm is demonstrated for the case of a polypeptide molecule with 400 residues.

  2. Fast algorithm for automatically computing Strahler stream order

    USGS Publications Warehouse

    Lanfear, Kenneth J.

    1990-01-01

    An efficient algorithm was developed to determine Strahler stream order for segments of stream networks represented in a Geographic Information System (GIS). The algorithm correctly assigns Strahler stream order in topologically complex situations such as braided streams and multiple drainage outlets. Execution time varies nearly linearly with the number of stream segments in the network. This technique is expected to be particularly useful for studying the topology of dense stream networks derived from digital elevation model data.

  3. Fast parallel algorithms for short-range molecular dynamics

    SciTech Connect

    Plimpton, S.

    1993-05-01

    Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a subset of atoms; the second assigns each a subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently -- those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 10,000,000 atoms on three parallel supercomputers, the nCUBE 2, Intel iPSC/860, and Intel Delta. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and the Intel Delta performs about 30 times faster than a single Y-MP processor and 12 times faster than a single C90 processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

  4. A fast neural-network algorithm for VLSI cell placement.

    PubMed

    Aykanat, Cevdet; Bultan, Tevfik; Haritaoğlu, Ismail

    1998-12-01

    Cell placement is an important phase of current VLSI circuit design styles such as standard cell, gate array, and Field Programmable Gate Array (FPGA). Although nondeterministic algorithms such as Simulated Annealing (SA) were successful in solving this problem, they are known to be slow. In this paper, a neural network algorithm is proposed that produces solutions as good as SA in substantially less time. This algorithm is based on Mean Field Annealing (MFA) technique, which was successfully applied to various combinatorial optimization problems. A MFA formulation for the cell placement problem is derived which can easily be applied to all VLSI design styles. To demonstrate that the proposed algorithm is applicable in practice, a detailed formulation for the FPGA design style is derived, and the layouts of several benchmark circuits are generated. The performance of the proposed cell placement algorithm is evaluated in comparison with commercial automated circuit design software Xilinx Automatic Place and Route (APR) which uses SA technique. Performance evaluation is conducted using ACM/SIGDA Design Automation benchmark circuits. Experimental results indicate that the proposed MFA algorithm produces comparable results with APR. However, MFA is almost 20 times faster than APR on the average. PMID:12662737

  5. Performance analysis of visual tracking algorithms for motion-based user interfaces on mobile devices

    NASA Astrophysics Data System (ADS)

    Winkler, Stefan; Rangaswamy, Karthik; Tedjokusumo, Jefry; Zhou, ZhiYing

    2008-02-01

    Determining the self-motion of a camera is useful for many applications. A number of visual motion-tracking algorithms have been developed till date, each with their own advantages and restrictions. Some of them have also made their foray into the mobile world, powering augmented reality-based applications on phones with inbuilt cameras. In this paper, we compare the performances of three feature or landmark-guided motion tracking algorithms, namely marker-based tracking with MXRToolkit, face tracking based on CamShift, and MonoSLAM. We analyze and compare the complexity, accuracy, sensitivity, robustness and restrictions of each of the above methods. Our performance tests are conducted over two stages: The first stage of testing uses video sequences created with simulated camera movements along the six degrees of freedom in order to compare accuracy in tracking, while the second stage analyzes the robustness of the algorithms by testing for manipulative factors like image scaling and frame-skipping.

  6. Dim moving target tracking algorithm based on particle discriminative sparse representation

    NASA Astrophysics Data System (ADS)

    Li, Zhengzhou; Li, Jianing; Ge, Fengzeng; Shao, Wanxing; Liu, Bing; Jin, Gang

    2016-03-01

    The small dim moving target usually submerged in strong noise, and its motion observability is debased by numerous false alarms for low signal-to-noise ratio (SNR). A target tracking algorithm based on particle filter and discriminative sparse representation is proposed in this paper to cope with the uncertainty of dim moving target tracking. The weight of every particle is the crucial factor to ensuring the accuracy of dim target tracking for particle filter (PF) that can achieve excellent performance even under the situation of non-linear and non-Gaussian motion. In discriminative over-complete dictionary constructed according to image sequence, the target dictionary describes target signal and the background dictionary embeds background clutter. The difference between target particle and background particle is enhanced to a great extent, and the weight of every particle is then measured by means of the residual after reconstruction using the prescribed number of target atoms and their corresponding coefficients. The movement state of dim moving target is then estimated and finally tracked by these weighted particles. Meanwhile, the subspace of over-complete dictionary is updated online by the stochastic estimation algorithm. Some experiments are induced and the experimental results show the proposed algorithm could improve the performance of moving target tracking by enhancing the consistency between the posteriori probability distribution and the moving target state.

  7. [Fast segmentation algorithm of high resolution remote sensing image based on multiscale mean shift].

    PubMed

    Wang, Lei-Guang; Zheng, Chen; Lin, Li-Yu; Chen, Rong-Yuan; Mei, Tian-Can

    2011-01-01

    Mean Shift algorithm is a robust approach toward feature space analysis and it has been used wildly for natural scene image and medical image segmentation. However, high computational complexity of the algorithm has constrained its application in remote sensing images with massive information. A fast image segmentation algorithm is presented by extending traditional mean shift method to wavelet domain. In order to evaluate the effectiveness of the proposed algorithm, multispectral remote sensing image and synthetic image are utilized. The results show that the proposed algorithm can improve the speed 5-7 times compared to the traditional MS method in the premise of segmentation quality assurance. PMID:21428083

  8. Through-Wall Multiple Targets Vital Signs Tracking Based on VMD Algorithm.

    PubMed

    Yan, Jiaming; Hong, Hong; Zhao, Heng; Li, Yusheng; Gu, Chen; Zhu, Xiaohua

    2016-01-01

    Targets located at the same distance are easily neglected in most through-wall multiple targets detecting applications which use the single-input single-output (SISO) ultra-wideband (UWB) radar system. In this paper, a novel multiple targets vital signs tracking algorithm for through-wall detection using SISO UWB radar has been proposed. Taking advantage of the high-resolution decomposition of the Variational Mode Decomposition (VMD) based algorithm, the respiration signals of different targets can be decomposed into different sub-signals, and then, we can track the time-varying respiration signals accurately when human targets located in the same distance. Intensive evaluation has been conducted to show the effectiveness of our scheme with a 0.15 m thick concrete brick wall. Constant, piecewise-constant and time-varying vital signs could be separated and tracked successfully with the proposed VMD based algorithm for two targets, even up to three targets. For the multiple targets' vital signs tracking issues like urban search and rescue missions, our algorithm has superior capability in most detection applications. PMID:27537880

  9. Tracking Problem Solving by Multivariate Pattern Analysis and Hidden Markov Model Algorithms

    ERIC Educational Resources Information Center

    Anderson, John R.

    2012-01-01

    Multivariate pattern analysis can be combined with Hidden Markov Model algorithms to track the second-by-second thinking as people solve complex problems. Two applications of this methodology are illustrated with a data set taken from children as they interacted with an intelligent tutoring system for algebra. The first "mind reading" application…

  10. A Linac Simulation Code for Macro-Particles Tracking and Steering Algorithm Implementation

    SciTech Connect

    sun, yipeng

    2012-05-03

    In this paper, a linac simulation code written in Fortran90 is presented and several simulation examples are given. This code is optimized to implement linac alignment and steering algorithms, and evaluate the accelerator errors such as RF phase and acceleration gradient, quadrupole and BPM misalignment. It can track a single particle or a bunch of particles through normal linear accelerator elements such as quadrupole, RF cavity, dipole corrector and drift space. One-to-one steering algorithm and a global alignment (steering) algorithm are implemented in this code.

  11. Visual Servoing of Quadrotor Micro-Air Vehicle Using Color-Based Tracking Algorithm

    NASA Astrophysics Data System (ADS)

    Azrad, Syaril; Kendoul, Farid; Nonami, Kenzo

    This paper describes a vision-based tracking system using an autonomous Quadrotor Unmanned Micro-Aerial Vehicle (MAV). The vision-based control system relies on color target detection and tracking algorithm using integral image, Kalman filters for relative pose estimation, and a nonlinear controller for the MAV stabilization and guidance. The vision algorithm relies on information from a single onboard camera. An arbitrary target can be selected in real-time from the ground control station, thereby outperforming template and learning-based approaches. Experimental results obtained from outdoor flight tests, showed that the vision-control system enabled the MAV to track and hover above the target as long as the battery is available. The target does not need to be pre-learned, or a template for detection. The results from image processing are sent to navigate a non-linear controller designed for the MAV by the researchers in our group.

  12. Least average residual algorithm (LARA) for tracking the motion of Arctic sea ice

    SciTech Connect

    Das Peddada, S.; McDevitt, R.

    1996-07-01

    Suppose one has two images A and B of a collection of ice floes taken at times t{sub 0} and t{sub 1}, respectively. Given an ice flow 1 in A, the authors develop a new automated tracking algorithm to track the position of A in image B. The proposed least average residual algorithm (LARA) performs a constrained search for matching ice floes by determining an appropriate search space for each floe to be tracked. LARA takes a stepwide approach with suitable decision rules at various stages. It takes into account various distinguishing characteristics such as: (i) the geometry of the ice field; (ii) size of an ice floe; and (iii) geometry of the floe. LARA also attempts to detect broken floes and amalgamated floes.

  13. A High-Speed Vision-Based Sensor for Dynamic Vibration Analysis Using Fast Motion Extraction Algorithms.

    PubMed

    Zhang, Dashan; Guo, Jie; Lei, Xiujun; Zhu, Changan

    2016-01-01

    The development of image sensor and optics enables the application of vision-based techniques to the non-contact dynamic vibration analysis of large-scale structures. As an emerging technology, a vision-based approach allows for remote measuring and does not bring any additional mass to the measuring object compared with traditional contact measurements. In this study, a high-speed vision-based sensor system is developed to extract structure vibration signals in real time. A fast motion extraction algorithm is required for this system because the maximum sampling frequency of the charge-coupled device (CCD) sensor can reach up to 1000 Hz. Two efficient subpixel level motion extraction algorithms, namely the modified Taylor approximation refinement algorithm and the localization refinement algorithm, are integrated into the proposed vision sensor. Quantitative analysis shows that both of the two modified algorithms are at least five times faster than conventional upsampled cross-correlation approaches and achieve satisfactory error performance. The practicability of the developed sensor is evaluated by an experiment in a laboratory environment and a field test. Experimental results indicate that the developed high-speed vision-based sensor system can extract accurate dynamic structure vibration signals by tracking either artificial targets or natural features. PMID:27110784

  14. A High-Speed Vision-Based Sensor for Dynamic Vibration Analysis Using Fast Motion Extraction Algorithms

    PubMed Central

    Zhang, Dashan; Guo, Jie; Lei, Xiujun; Zhu, Changan

    2016-01-01

    The development of image sensor and optics enables the application of vision-based techniques to the non-contact dynamic vibration analysis of large-scale structures. As an emerging technology, a vision-based approach allows for remote measuring and does not bring any additional mass to the measuring object compared with traditional contact measurements. In this study, a high-speed vision-based sensor system is developed to extract structure vibration signals in real time. A fast motion extraction algorithm is required for this system because the maximum sampling frequency of the charge-coupled device (CCD) sensor can reach up to 1000 Hz. Two efficient subpixel level motion extraction algorithms, namely the modified Taylor approximation refinement algorithm and the localization refinement algorithm, are integrated into the proposed vision sensor. Quantitative analysis shows that both of the two modified algorithms are at least five times faster than conventional upsampled cross-correlation approaches and achieve satisfactory error performance. The practicability of the developed sensor is evaluated by an experiment in a laboratory environment and a field test. Experimental results indicate that the developed high-speed vision-based sensor system can extract accurate dynamic structure vibration signals by tracking either artificial targets or natural features. PMID:27110784

  15. A new hybrid algorithm for computing a fast discrete Fourier transform

    NASA Technical Reports Server (NTRS)

    Reed, I. S.; Truong, T. K.

    1979-01-01

    In this paper for certain long transform lengths, Winograd's algorithm for computing the discrete Fourier transform (DFT) is extended considerably. This is accomplished by performing the cyclic convolution, required by Winograd's method, with the Mersenne prime number-theoretic transform developed originally by Rader. This new algorithm requires fewer multiplications than either the standard fast Fourier transform (FFT) or Winograd's more conventional algorithm. However, more additions are required.

  16. Fast Combinatorial Algorithm for the Solution of Linearly Constrained Least Squares Problems

    DOEpatents

    Van Benthem, Mark H.; Keenan, Michael R.

    2008-11-11

    A fast combinatorial algorithm can significantly reduce the computational burden when solving general equality and inequality constrained least squares problems with large numbers of observation vectors. The combinatorial algorithm provides a mathematically rigorous solution and operates at great speed by reorganizing the calculations to take advantage of the combinatorial nature of the problems to be solved. The combinatorial algorithm exploits the structure that exists in large-scale problems in order to minimize the number of arithmetic operations required to obtain a solution.

  17. International collaborative project to compare and track the nutritional composition of fast foods

    PubMed Central

    2012-01-01

    Background Chronic diseases are the leading cause of premature death and disability in the world with over-nutrition a primary cause of diet-related ill health. Excess quantities of energy, saturated fat, sugar and salt derived from fast foods contribute importantly to this disease burden. Our objective is to collate and compare nutrient composition data for fast foods as a means of supporting improvements in product formulation. Methods/design Surveys of fast foods will be done in each participating country each year. Information on the nutrient composition for each product will be sought either through direct chemical analysis, from fast food companies, in-store materials or from company websites. Foods will be categorized into major groups for the primary analyses which will compare mean levels of saturated fat, sugar, sodium, energy and serving size at baseline and over time. Countries currently involved include Australia, New Zealand, France, UK, USA, India, Spain, China and Canada, with more anticipated to follow. Discussion This collaborative approach to the collation and sharing of data will enable low-cost tracking of fast food composition around the world. This project represents a significant step forward in the objective and transparent monitoring of industry and government commitments to improve the quality of fast foods. PMID:22838731

  18. Evaluation of optical flow algorithms for tracking endocardial surfaces on three-dimensional ultrasound data

    NASA Astrophysics Data System (ADS)

    Duan, Qi; Angelini, Elsa D.; Herz, Susan L.; Ingrassia, Christopher M.; Gerard, Olivier; Costa, Kevin D.; Holmes, Jeffrey W.; Laine, Andrew F.

    2005-04-01

    With relatively high frame rates and the ability to acquire volume data sets with a stationary transducer, 3D ultrasound systems, based on matrix phased array transducers, provide valuable three-dimensional information, from which quantitative measures of cardiac function can be extracted. Such analyses require segmentation and visual tracking of the left ventricular endocardial border. Due to the large size of the volumetric data sets, manual tracing of the endocardial border is tedious and impractical for clinical applications. Therefore the development of automatic methods for tracking three-dimensional endocardial motion is essential. In this study, we evaluate a four-dimensional optical flow motion tracking algorithm to determine its capability to follow the endocardial border in three dimensional ultrasound data through time. The four-dimensional optical flow method was implemented using three-dimensional correlation. We tested the algorithm on an experimental open-chest dog data set and a clinical data set acquired with a Philips' iE33 three-dimensional ultrasound machine. Initialized with left ventricular endocardial data points obtained from manual tracing at end-diastole, the algorithm automatically tracked these points frame by frame through the whole cardiac cycle. A finite element surface was fitted through the data points obtained by both optical flow tracking and manual tracing by an experienced observer for quantitative comparison of the results. Parameterization of the finite element surfaces was performed and maps displaying relative differences between the manual and semi-automatic methods were compared. The results showed good consistency between manual tracing and optical flow estimation on 73% of the entire surface with fewer than 10% difference. In addition, the optical flow motion tracking algorithm greatly reduced processing time (about 94% reduction compared to human involvement per cardiac cycle) for analyzing cardiac function in three

  19. Simple, fast codebook training algorithm by entropy sequence for vector quantization

    NASA Astrophysics Data System (ADS)

    Pang, Chao-yang; Yao, Shaowen; Qi, Zhang; Sun, Shi-xin; Liu, Jingde

    2001-09-01

    The traditional training algorithm for vector quantization such as the LBG algorithm uses the convergence of distortion sequence as the condition of the end of algorithm. We presented a novel training algorithm for vector quantization in this paper. The convergence of the entropy sequence of each region sequence is employed as the condition of the end of the algorithm. Compared with the famous LBG algorithm, it is simple, fast and easy to be comprehended and controlled. We test the performance of the algorithm by typical test image Lena and Barb. The result shows that the PSNR difference between the algorithm and LBG is less than 0.1dB, but the running time of it is at most one second of LBG.

  20. Outline of a fast hardware implementation of Winograd's DFT algorithm

    NASA Technical Reports Server (NTRS)

    Zohar, S.

    1980-01-01

    The main characteristics of the discrete Fourier transform (DFT) algorithm considered by Winograd (1976) is a significant reduction in the number of multiplications. Its primary disadvantage is a higher structural complexity. It is, therefore, difficult to translate the reduced number of multiplications into faster execution of the DFT by means of a software implementation of the algorithm. For this reason, a hardware implementation is considered in the current study, taking into account a design based on the algorithm prescription discussed by Zohar (1979). The hardware implementation of a FORTRAN subroutine is proposed, giving attention to a pipelining scheme in which 5 consecutive data batches are being operated on simultaneously, each batch undergoing one of 5 processing phases.

  1. BFL: a node and edge betweenness based fast layout algorithm for large scale networks

    PubMed Central

    Hashimoto, Tatsunori B; Nagasaki, Masao; Kojima, Kaname; Miyano, Satoru

    2009-01-01

    Background Network visualization would serve as a useful first step for analysis. However, current graph layout algorithms for biological pathways are insensitive to biologically important information, e.g. subcellular localization, biological node and graph attributes, or/and not available for large scale networks, e.g. more than 10000 elements. Results To overcome these problems, we propose the use of a biologically important graph metric, betweenness, a measure of network flow. This metric is highly correlated with many biological phenomena such as lethality and clusters. We devise a new fast parallel algorithm calculating betweenness to minimize the preprocessing cost. Using this metric, we also invent a node and edge betweenness based fast layout algorithm (BFL). BFL places the high-betweenness nodes to optimal positions and allows the low-betweenness nodes to reach suboptimal positions. Furthermore, BFL reduces the runtime by combining a sequential insertion algorim with betweenness. For a graph with n nodes, this approach reduces the expected runtime of the algorithm to O(n2) when considering edge crossings, and to O(n log n) when considering only density and edge lengths. Conclusion Our BFL algorithm is compared against fast graph layout algorithms and approaches requiring intensive optimizations. For gene networks, we show that our algorithm is faster than all layout algorithms tested while providing readability on par with intensive optimization algorithms. We achieve a 1.4 second runtime for a graph with 4000 nodes and 12000 edges on a standard desktop computer. PMID:19146673

  2. A fast non-local image denoising algorithm

    NASA Astrophysics Data System (ADS)

    Dauwe, A.; Goossens, B.; Luong, H. Q.; Philips, W.

    2008-02-01

    In this paper we propose several improvements to the original non-local means algorithm introduced by Buades et al. which obtains state-of-the-art denoising results. The strength of this algorithm is to exploit the repetitive character of the image in order to denoise the image unlike conventional denoising algorithms, which typically operate in a local neighbourhood. Due to the enormous amount of weight computations, the original algorithm has a high computational cost. An improvement of image quality towards the original algorithm is to ignore the contributions from dissimilar windows. Even though their weights are very small at first sight, the new estimated pixel value can be severely biased due to the many small contributions. This bad influence of dissimilar windows can be eliminated by setting their corresponding weights to zero. Using the preclassification based on the first three statistical moments, only contributions from similar neighborhoods are computed. To decide whether a window is similar or dissimilar, we will derive thresholds for images corrupted with additive white Gaussian noise. Our accelerated approach is further optimized by taking advantage of the symmetry in the weights, which roughly halves the computation time, and by using a lookup table to speed up the weight computations. Compared to the original algorithm, our proposed method produces images with increased PSNR and better visual performance in less computation time. Our proposed method even outperforms state-of-the-art wavelet denoising techniques in both visual quality and PSNR values for images containing a lot of repetitive structures such as textures: the denoised images are much sharper and contain less artifacts. The proposed optimizations can also be applied in other image processing tasks which employ the concept of repetitive structures such as intra-frame super-resolution or detection of digital image forgery.

  3. Gradient maintenance: A new algorithm for fast online replanning

    SciTech Connect

    Ahunbay, Ergun E. Li, X. Allen

    2015-06-15

    Purpose: Clinical use of online adaptive replanning has been hampered by the unpractically long time required to delineate volumes based on the image of the day. The authors propose a new replanning algorithm, named gradient maintenance (GM), which does not require the delineation of organs at risk (OARs), and can enhance automation, drastically reducing planning time and improving consistency and throughput of online replanning. Methods: The proposed GM algorithm is based on the hypothesis that if the dose gradient toward each OAR in daily anatomy can be maintained the same as that in the original plan, the intended plan quality of the original plan would be preserved in the adaptive plan. The algorithm requires a series of partial concentric rings (PCRs) to be automatically generated around the target toward each OAR on the planning and the daily images. The PCRs are used in the daily optimization objective function. The PCR dose constraints are generated with dose–volume data extracted from the original plan. To demonstrate this idea, GM plans generated using daily images acquired using an in-room CT were compared to regular optimization and image guided radiation therapy repositioning plans for representative prostate and pancreatic cancer cases. Results: The adaptive replanning using the GM algorithm, requiring only the target contour from the CT of the day, can be completed within 5 min without using high-power hardware. The obtained adaptive plans were almost as good as the regular optimization plans and were better than the repositioning plans for the cases studied. Conclusions: The newly proposed GM replanning algorithm, requiring only target delineation, not full delineation of OARs, substantially increased planning speed for online adaptive replanning. The preliminary results indicate that the GM algorithm may be a solution to improve the ability for automation and may be especially suitable for sites with small-to-medium size targets surrounded by

  4. Fast algorithms for transport models. Technical progress report

    SciTech Connect

    Manteuffel, T.A.

    1992-12-01

    The objective of this project is the development of numerical solution techniques for deterministic models of the transport of neutral and charged particles and the demonstration of their effectiveness in both a production environment and on advanced architecture computers. The primary focus is on various versions of the linear Boltzman equation. These equations are fundamental in many important applications. This project is an attempt to integrate the development of numerical algorithms with the process of developing production software. A major thrust of this reject will be the implementation of these algorithms on advanced architecture machines that reside at the Advanced Computing Laboratory (ACL) at Los Alamos National Laboratories (LANL).

  5. A Simple and Fast Spline Filtering Algorithm for Surface Metrology

    PubMed Central

    Zhang, Hao; Ott, Daniel; Song, John; Tong, Mingsi; Chu, Wei

    2015-01-01

    Spline filters and their corresponding robust filters are commonly used filters recommended in ISO (the International Organization for Standardization) standards for surface evaluation. Generally, these linear and non-linear spline filters, composed of symmetric, positive-definite matrices, are solved in an iterative fashion based on a Cholesky decomposition. They have been demonstrated to be relatively efficient, but complicated and inconvenient to implement. A new spline-filter algorithm is proposed by means of the discrete cosine transform or the discrete Fourier transform. The algorithm is conceptually simple and very convenient to implement. PMID:26958443

  6. RaceTrack: An Approximation Algorithm for the Mobile Sink Routing Problem

    NASA Astrophysics Data System (ADS)

    Yuan, Yuan; Peng, Yuxing

    In large-scale monitoring applications, randomly deployed wireless sensor networks may not be fully connected. Using mobile sink for data collection is one of the feasible solutions. For energy saving, it is necessary to plan a shortest route for the mobile sink. Mobile sink routing problem can be regarded as a special case of TSP with neighborhoods (TSPN) problem. In this paper, we propose a novel approximation algorithm called RaceTrack. This algorithm forms a "racetrack" based on the TSP route, which is constructed from the locations of the deployed sensor nodes. By using inner lane heuristic and concave bend heuristic of auto racing, and a shortcut finding step, we optimize the obtained TSP route within O(n) computation time. Through formal proofs and large-scale simulations, we verified that our RaceTrack algorithm can achieve a good approximation ratio.

  7. 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.

  8. Target-tracking and identity management algorithms for air traffic surveillance

    NASA Astrophysics Data System (ADS)

    Balakrishnan, Hamsa

    The air traffic control system of the United States is responsible for managing traffic in the National Airspace System; safety is a paramount concern. The air traffic surveillance network has the task of collecting and processing information on the positions, velocities and identities of the aircraft in the system, before presenting it to air traffic controllers to use in maintaining an orderly flow of traffic. This dissertation attempts to design techniques that provide controllers with high-fidelity information about the aircraft in their controlled airspace, using the observations of the air traffic surveillance network. We propose algorithms for the efficient tracking of aircraft, as well as for maintaining beliefs of their identities. Such methods would improve the processing of aircraft situation data, particularly in a congested airspace with general aviation. In this thesis, we propose an algorithmic framework for the simultaneous tracking and identity management of multiple maneuvering targets. We design an algorithm that efficiently tracks the positions, velocities, flight modes, and identities of multiple aircraft in cluttered environments. We tackle the challenges of data association, identity management and state estimation of aircraft trajectories by proposing a modification of the Joint Probabilistic Data Association algorithm, an algorithm based on identity-mass flow, and a state estimation algorithm for tracking hybrid systems, respectively. The identity of each aircraft, an essential feature of aircraft situation data, is often not available but needs to be inferred from radar observations, and maintained in terms of probabilities. We present an algorithm to update the probabilistic matrices that represent the belief of aircraft identities, in the presence of intermittent measurements. We demonstrate the performance of the framework using examples drawn from air traffic surveillance. We also consider the problem of identifying stochastic hybrid

  9. Fast Quantum Algorithms for Numerical Integrals and Stochastic Processes

    NASA Technical Reports Server (NTRS)

    Abrams, D.; Williams, C.

    1999-01-01

    We discuss quantum algorithms that calculate numerical integrals and descriptive statistics of stochastic processes. With either of two distinct approaches, one obtains an exponential speed increase in comparison to the fastest known classical deterministic algotithms and a quadratic speed increase incomparison to classical Monte Carlo methods.

  10. Attitude determination using vector observations: A fast optimal matrix algorithm

    NASA Technical Reports Server (NTRS)

    Markley, F. Landis

    1993-01-01

    The attitude matrix minimizing Wahba's loss function is computed directly by a method that is competitive with the fastest known algorithm for finding this optimal estimate. The method also provides an estimate of the attitude error covariance matrix. Analysis of the special case of two vector observations identifies those cases for which the TRIAD or algebraic method minimizes Wahba's loss function.

  11. Fast algorithms for combustion kinetics calculations: A comparison

    NASA Technical Reports Server (NTRS)

    Radhakrishnan, K.

    1984-01-01

    To identify the fastest algorithm currently available for the numerical integration of chemical kinetic rate equations, several algorithms were examined. Findings to date are summarized. The algorithms examined include two general-purpose codes EPISODE and LSODE and three special-purpose (for chemical kinetic calculations) codes CHEMEQ, CRK1D, and GCKP84. In addition, an explicit Runge-Kutta-Merson differential equation solver (IMSL Routine DASCRU) is used to illustrate the problems associated with integrating chemical kinetic rate equations by a classical method. Algorithms were applied to two test problems drawn from combustion kinetics. These problems included all three combustion regimes: induction, heat release and equilibration. Variations of the temperature and species mole fraction are given with time for test problems 1 and 2, respectively. Both test problems were integrated over a time interval of 1 ms in order to obtain near-equilibration of all species and temperature. Of the codes examined in this study, only CREK1D and GCDP84 were written explicitly for integrating exothermic, non-isothermal combustion rate equations. These therefore have built-in procedures for calculating the temperature.

  12. An Iterative CT Reconstruction Algorithm for Fast Fluid Flow Imaging.

    PubMed

    Van Eyndhoven, Geert; Batenburg, K Joost; Kazantsev, Daniil; Van Nieuwenhove, Vincent; Lee, Peter D; Dobson, Katherine J; Sijbers, Jan

    2015-11-01

    The study of fluid flow through solid matter by computed tomography (CT) imaging has many applications, ranging from petroleum and aquifer engineering to biomedical, manufacturing, and environmental research. To avoid motion artifacts, current experiments are often limited to slow fluid flow dynamics. This severely limits the applicability of the technique. In this paper, a new iterative CT reconstruction algorithm for improved a temporal/spatial resolution in the imaging of fluid flow through solid matter is introduced. The proposed algorithm exploits prior knowledge in two ways. First, the time-varying object is assumed to consist of stationary (the solid matter) and dynamic regions (the fluid flow). Second, the attenuation curve of a particular voxel in the dynamic region is modeled by a piecewise constant function over time, which is in accordance with the actual advancing fluid/air boundary. Quantitative and qualitative results on different simulation experiments and a real neutron tomography data set show that, in comparison with the state-of-the-art algorithms, the proposed algorithm allows reconstruction from substantially fewer projections per rotation without image quality loss. Therefore, the temporal resolution can be substantially increased, and thus fluid flow experiments with faster dynamics can be performed. PMID:26259219

  13. Towards designing an optical-flow based colonoscopy tracking algorithm: a comparative study

    NASA Astrophysics Data System (ADS)

    Liu, Jianfei; Subramanian, Kalpathi R.; Yoo, Terry S.

    2013-03-01

    Automatic co-alignment of optical and virtual colonoscopy images can supplement traditional endoscopic procedures, by providing more complete information of clinical value to the gastroenterologist. In this work, we present a comparative analysis of our optical flow based technique for colonoscopy tracking, in relation to current state of the art methods, in terms of tracking accuracy, system stability, and computational efficiency. Our optical-flow based colonoscopy tracking algorithm starts with computing multi-scale dense and sparse optical flow fields to measure image displacements. Camera motion parameters are then determined from optical flow fields by employing a Focus of Expansion (FOE) constrained egomotion estimation scheme. We analyze the design choices involved in the three major components of our algorithm: dense optical flow, sparse optical flow, and egomotion estimation. Brox's optical flow method,1 due to its high accuracy, was used to compare and evaluate our multi-scale dense optical flow scheme. SIFT6 and Harris-affine features7 were used to assess the accuracy of the multi-scale sparse optical flow, because of their wide use in tracking applications; the FOE-constrained egomotion estimation was compared with collinear,2 image deformation10 and image derivative4 based egomotion estimation methods, to understand the stability of our tracking system. Two virtual colonoscopy (VC) image sequences were used in the study, since the exact camera parameters(for each frame) were known; dense optical flow results indicated that Brox's method was superior to multi-scale dense optical flow in estimating camera rotational velocities, but the final tracking errors were comparable, viz., 6mm vs. 8mm after the VC camera traveled 110mm. Our approach was computationally more efficient, averaging 7.2 sec. vs. 38 sec. per frame. SIFT and Harris affine features resulted in tracking errors of up to 70mm, while our sparse optical flow error was 6mm. The comparison

  14. Fast adaptive schemes for tracking voltage phasor and local frequency in power transmission and distribution systems

    SciTech Connect

    Kamwa, I.; Grondin, R. )

    1992-04-01

    Real-time measurements of voltage phasor and local frequency deviation find applications in computer-based relaying, static state estimation, disturbance monitoring and control. This paper proposes two learning schemes for fast estimation of these basic quantities. We attacked the problem from a system identification perspective, in opposition to the well-established Extended Kalman Filtering (EKF) technique. It is shown that, from a simple non-linear model of the system voltage which involves only two parameters, the Recursive Least Squares (RLS) and the Least Means Squares (LMS) algorithms can each provide dynamic estimates of the voltage phasor. The finite derivative of the phase deviation, followed by a moving-average filter, then leads to the local frequency deviation. A constant forgetting factor included in these algorithms provides both fast adaptation in time-varying situations and good smoothing of the estimates when necessary.

  15. Feature-based tracking algorithms for imaging infrared anti-ship missiles

    NASA Astrophysics Data System (ADS)

    Gray, Greer J.; Aouf, Nabil; Richardson, Mark A.; Butters, Brian; Walmsley, Roy; Nicholls, Edgar

    2011-11-01

    This paper investigates feature based tracking algorithms that could be used within models of imaging infrared anti-ship missile seekers in a simulation environment. The algorithms use global shape based object features such as Fourier Descriptors or Hu Moments to track a target in rendered sensor images. A template of the desired target is saved during acquisition, and matching is performed between the template and the features of unknown objects extracted from subsequent sensor images. The centroid of the object that matches the best becomes the seeker aim-point. A seeker using local features, generated by the Scale Invariant Feature Transform, to track objects will also be examined. It discriminates between objects within the sensor images by clustering SIFT features that have neighbouring regions of similar intensity. The cluster of features whose average neighbouring intensity is the closest to a desired target template is chosen as the highest priority cluster. A variable radius distance metric is used to reject features in this cluster that are too far from the seeker's previous aim-point. The new aim-point is calculated as the centroid of the cluster of remaining features. Comparisons of the three algorithms' ability to track a naval vessel deploying countermeasures will be also presented.

  16. Single-Cell Tracking with PET using a Novel Trajectory Reconstruction Algorithm

    PubMed Central

    Lee, Keum Sil; Kim, Tae Jin

    2015-01-01

    Virtually all biomedical applications of positron emission tomography (PET) use images to represent the distribution of a radiotracer. However, PET is increasingly used in cell tracking applications, for which the “imaging” paradigm may not be optimal. Here we investigate an alternative approach, which consists in reconstructing the time-varying position of individual radiolabeled cells directly from PET measurements. As a proof of concept, we formulate a new algorithm for reconstructing the trajectory of one single moving cell directly from list-mode PET data. We model the trajectory as a 3D B-spline function of the temporal variable and use non-linear optimization to minimize the mean-square distance between the trajectory and the recorded list-mode coincidence events. Using Monte Carlo simulations (GATE), we show that this new algorithm can track a single source moving within a small-animal PET system with <3 mm accuracy provided that the activity of the cell [Bq] is greater than four times its velocity [mm/s]. The algorithm outperforms conventional ML-EM as well as the “minimum distance” method used for positron emission particle tracking (PEPT). The new method was also successfully validated using experimentally acquired PET data. In conclusion, we demonstrated the feasibility of a new method for tracking a single moving cell directly from PET list-mode data, at the whole-body level, for physiologically relevant activities and velocities. PMID:25423651

  17. Accuracy Refinement Algorithm for Mobile Target Location Tracking by Radio Signal Strength Indication Approach

    NASA Astrophysics Data System (ADS)

    Lau, Erin-Ee-Lin; Chung, Wan-Young

    A novel RSSI (Received Signal Strength Indication) refinement algorithm is proposed to enhance the resolution for indoor and outdoor real-time location tracking system. The proposed refinement algorithm is implemented in two separate phases. During the first phase, called the pre-processing step, RSSI values at different static locations are collected and processed to build a calibrated model for each reference node. Different measurement campaigns pertinent to each parameter in the model are implemented to analyze the sensitivity of RSSI. The propagation models constructed for each reference nodes are needed by the second phase. During the next phase, called the runtime process, real-time tracking is performed. Smoothing algorithm is proposed to minimize the dynamic fluctuation of radio signal received from each reference node when the mobile target is moving. Filtered RSSI values are converted to distances using formula calibrated in the first phase. Finally, an iterative trilateration algorithm is used for position estimation. Experiments relevant to the optimization algorithm are carried out in both indoor and outdoor environments and the results validated the feasibility of proposed algorithm in reducing the dynamic fluctuation for more accurate position estimation.

  18. A Fast Implementation of the ISODATA Clustering Algorithm

    NASA Technical Reports Server (NTRS)

    Memarsadeghi, Nargess; Mount, David M.; Netanyahu, Nathan S.; LeMoigne, Jacqueline

    2005-01-01

    Clustering is central to many image processing and remote sensing applications. ISODATA is one of the most popular and widely used clustering methods in geoscience applications, but it can run slowly, particularly with large data sets. We present a more efficient approach to ISODATA clustering, which achieves better running times by storing the points in a kd-tree and through a modification of the way in which the algorithm estimates the dispersion of each cluster. We also present an approximate version of the algorithm which allows the user to further improve the running time, at the expense of lower fidelity in computing the nearest cluster center to each point. We provide both theoretical and empirical justification that our modified approach produces clusterings that are very similar to those produced by the standard ISODATA approach. We also provide empirical studies on both synthetic data and remotely sensed Landsat and MODIS images that show that our approach has significantly lower running times.

  19. Compressed Sensing Photoacoustic Imaging Based on Fast Alternating Direction Algorithm

    PubMed Central

    Liu, Xueyan; Peng, Dong; Guo, Wei; Ma, Xibo; Yang, Xin; Tian, Jie

    2012-01-01

    Photoacoustic imaging (PAI) has been employed to reconstruct endogenous optical contrast present in tissues. At the cost of longer calculations, a compressive sensing reconstruction scheme can achieve artifact-free imaging with fewer measurements. In this paper, an effective acceleration framework using the alternating direction method (ADM) was proposed for recovering images from limited-view and noisy observations. Results of the simulation demonstrated that the proposed algorithm could perform favorably in comparison to two recently introduced algorithms in computational efficiency and data fidelity. In particular, it ran considerably faster than these two methods. PAI with ADM can improve convergence speed with fewer ultrasonic transducers, enabling a high-performance and cost-effective PAI system for biomedical applications. PMID:23365553

  20. Sunspots and Coronal Bright Points Tracking using a Hybrid Algorithm of PSO and Active Contour Model

    NASA Astrophysics Data System (ADS)

    Dorotovic, I.; Shahamatnia, E.; Lorenc, M.; Rybansky, M.; Ribeiro, R. A.; Fonseca, J. M.

    2014-02-01

    In the last decades there has been a steady increase of high-resolution data, from ground-based and space-borne solar instruments, and also of solar data volume. These huge image archives require efficient automatic image processing software tools capable of detecting and tracking various features in the solar atmosphere. Results of application of such tools are essential for studies of solar activity evolution, climate change understanding and space weather prediction. The follow up of interplanetary and near-Earth phenomena requires, among others, automatic tracking algorithms that can determine where a feature is located, on successive images taken along the period of observation. Full-disc solar images, obtained both with the ground-based solar telescopes and the instruments onboard the satellites, provide essential observational material for solar physicists and space weather researchers for better understanding the Sun, studying the evolution of various features in the solar atmosphere, and also investigating solar differential rotation by tracking such features along time. Here we demonstrate and discuss the suitability of applying a hybrid Particle Swarm Optimization (PSO) algorithm and Active Contour model for tracking and determining the differential rotation of sunspots and coronal bright points (CBPs) on a set of selected solar images. The results obtained confirm that the proposed approach constitutes a promising tool for investigating the evolution of solar activity and also for automating tracking features on massive solar image archives.

  1. Fast algorithms for improved speech coding and recognition

    NASA Astrophysics Data System (ADS)

    Turner, J. M.; Morf, M.; Stirling, W.; Shynk, J.; Huang, S. S.

    1983-12-01

    This research effort has studied estimation techniques for processes that contain Gaussian noise and jump components, and classification methods for transitional signals by using recursive estimation with vector quantization. The major accomplishments presented are an algorithm for joint estimation of excitation and vocal tract response, a pitch pulse location method using recursive least squares estimation, and a stop consonant recognition method using recursive estimation and vector quantization.

  2. Fast automatic algorithm for bifurcation detection in vascular CTA scans

    NASA Astrophysics Data System (ADS)

    Brozio, Matthias; Gorbunova, Vladlena; Godenschwager, Christian; Beck, Thomas; Bernhardt, Dominik

    2012-02-01

    Endovascular imaging aims at identifying vessels and their branches. Automatic vessel segmentation and bifurcation detection eases both clinical research and routine work. In this article a state of the art bifurcation detection algorithm is developed and applied on vascular computed tomography angiography (CTA) scans to mark the common iliac artery and its branches, the internal and external iliacs. In contrast to other methods our algorithm does not rely on a complete segmentation of a vessel in the 3D volume, but evaluates the cross-sections of the vessel slice by slice. Candidates for vessels are obtained by thresholding, following by 2D connected component labeling and prefiltering by size and position. The remaining candidates are connected in a squared distanced weighted graph. With Dijkstra algorithm the graph is traversed to get candidates for the arteries. We use another set of features considering length and shape of the paths to determine the best candidate and detect the bifurcation. The method was tested on 119 datasets acquired with different CT scanners and varying protocols. Both easy to evaluate datasets with high resolution and no apparent clinical diseases and difficult ones with low resolution, major calcifications, stents or poor contrast between the vessel and surrounding tissue were included. The presented results are promising, in 75.7% of the cases the bifurcation was labeled correctly, and in 82.7% the common artery and one of its branches were assigned correctly. The computation time was on average 0.49 s +/- 0.28 s, close to human interaction time, which makes the algorithm applicable for time-critical applications.

  3. FPGA design and implementation of a fast pixel purity index algorithm for endmember extraction in hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Valencia, David; Plaza, Antonio; Vega-Rodríguez, Miguel A.; Pérez, Rosa M.

    2005-11-01

    Hyperspectral imagery is a class of image data which is used in many scientific areas, most notably, medical imaging and remote sensing. It is characterized by a wealth of spatial and spectral information. Over the last years, many algorithms have been developed with the purpose of finding "spectral endmembers," which are assumed to be pure signatures in remotely sensed hyperspectral data sets. Such pure signatures can then be used to estimate the abundance or concentration of materials in mixed pixels, thus allowing sub-pixel analysis which is crucial in many remote sensing applications due to current sensor optics and configuration. One of the most popular endmember extraction algorithms has been the pixel purity index (PPI), available from Kodak's Research Systems ENVI software package. This algorithm is very time consuming, a fact that has generally prevented its exploitation in valid response times in a wide range of applications, including environmental monitoring, military applications or hazard and threat assessment/tracking (including wildland fire detection, oil spill mapping and chemical and biological standoff detection). Field programmable gate arrays (FPGAs) are hardware components with millions of gates. Their reprogrammability and high computational power makes them particularly attractive in remote sensing applications which require a response in near real-time. In this paper, we present an FPGA design for implementation of PPI algorithm which takes advantage of a recently developed fast PPI (FPPI) algorithm that relies on software-based optimization. The proposed FPGA design represents our first step toward the development of a new reconfigurable system for fast, onboard analysis of remotely sensed hyperspectral imagery.

  4. Fast motion prediction algorithm for multiview video coding

    NASA Astrophysics Data System (ADS)

    Abdelazim, Abdelrahman; Zhang, Guang Y.; Mein, Stephen J.; Varley, Martin R.; Ait-Boudaoud, Djamel

    2011-06-01

    Multiview Video Coding (MVC) is an extension to the H.264/MPEG-4 AVC video compression standard developed with joint efforts by MPEG/VCEG to enable efficient encoding of sequences captured simultaneously from multiple cameras using a single video stream. Therefore the design is aimed at exploiting inter-view dependencies in addition to reducing temporal redundancies. However, this further increases the overall encoding complexity In this paper, the high correlation between a macroblock and its enclosed partitions is utilised to estimate motion homogeneity, and based on the result inter-view prediction is selectively enabled or disabled. Moreover, if the MVC is divided into three layers in terms of motion prediction; the first being the full and sub-pixel motion search, the second being the mode selection process and the third being repetition of the first and second for inter-view prediction, the proposed algorithm significantly reduces the complexity in the three layers. To assess the proposed algorithm, a comprehensive set of experiments were conducted. The results show that the proposed algorithm significantly reduces the motion estimation time whilst maintaining similar Rate Distortion performance, when compared to both the H.264/MVC reference software and recently reported work.

  5. Constant Modulus Algorithm with Reduced Complexity Employing DFT Domain Fast Filtering

    NASA Astrophysics Data System (ADS)

    Yang, Yoon Gi; Lee, Chang Su; Yang, Soo Mi

    In this paper, a novel CMA (constant modulus algorithm) algorithm employing fast convolution in the DFT (discrete Fourier transform) domain is proposed. We propose a non-linear adaptation algorithm that minimizes CMA cost function in the DFT domain. The proposed algorithm is completely new one as compared to the recently introduced similar DFT domain CMA algorithm in that, the original CMA cost function has not been changed to develop DFT domain algorithm, resulting improved convergence properties. Using the proposed approach, we can reduce the number of multiplications to O(N log 2 N), whereas the conventional CMA has the computation order of O(N2). Simulation results show that the proposed algorithm provides a comparable performance to the conventional CMA.

  6. Fast time-reversible algorithms for molecular dynamics of rigid-body systems.

    PubMed

    Kajima, Yasuhiro; Hiyama, Miyabi; Ogata, Shuji; Kobayashi, Ryo; Tamura, Tomoyuki

    2012-06-21

    In this paper, we present time-reversible simulation algorithms for rigid bodies in the quaternion representation. By advancing a time-reversible algorithm [Y. Kajima, M. Hiyama, S. Ogata, and T. Tamura, J. Phys. Soc. Jpn. 80, 114002 (2011)] that requires iterations in calculating the angular velocity at each time step, we propose two kinds of iteration-free fast time-reversible algorithms. They are easily implemented in codes. The codes are compared with that of existing algorithms through demonstrative simulation of a nanometer-sized water droplet to find their stability of the total energy and computation speeds. PMID:22779579

  7. A fast algorithm for the calculation of junction capacitance and its application for impurity profile determination.

    NASA Technical Reports Server (NTRS)

    De Man, H. J. J.

    1972-01-01

    A fast algorithm is described which calculates the space charge layer width and junction capacitance for an arbitrary impurity profile and for plane, cylindrical and spherical junctions. The algorithm is based on the abrupt space charge edge (ASCE) approximation. A method to use the algorithm for the determination of impurity profiles for two-sided junctions is presented. An expression is derived for the built-in voltage to be used for capacitance calculations with the ASCE approximation. Experimental evidence is given that the algorithm permits very accurate capacitance calculations and also predicts the exact temperature dependence of the junction capacitance.

  8. A fast algorithm for nonlinear finite element analysis using equivalent magnetization current

    NASA Astrophysics Data System (ADS)

    Lee, Joon-Ho; Park, Il-Han; Kim, Dong-Hun; Lee, Ki-Sik

    2002-05-01

    A fast algorithm for iterative nonlinear finite element analysis is presented in this paper. The algorithm replaces updated permeability by an equivalent magnetization current and moves it to the source current term. Once the initial system matrix is decomposed in the LU form, the iterative procedure involves the trivial step of back-substitution from the LU form. Consequently, the computation time for the nonlinear analysis is greatly reduced. A numerical model of a cylindrical conductor enclosed with saturable iron is tested to validate the proposed algorithm. Numerical results are compared with those obtained using conventional Newton-Raphson algorithm in respect to accuracy and computational time.

  9. Fast and accurate image recognition algorithms for fresh produce food safety sensing

    NASA Astrophysics Data System (ADS)

    Yang, Chun-Chieh; Kim, Moon S.; Chao, Kuanglin; Kang, Sukwon; Lefcourt, Alan M.

    2011-06-01

    This research developed and evaluated the multispectral algorithms derived from hyperspectral line-scan fluorescence imaging under violet LED excitation for detection of fecal contamination on Golden Delicious apples. The algorithms utilized the fluorescence intensities at four wavebands, 680 nm, 684 nm, 720 nm, and 780 nm, for computation of simple functions for effective detection of contamination spots created on the apple surfaces using four concentrations of aqueous fecal dilutions. The algorithms detected more than 99% of the fecal spots. The effective detection of feces showed that a simple multispectral fluorescence imaging algorithm based on violet LED excitation may be appropriate to detect fecal contamination on fast-speed apple processing lines.

  10. The small-voxel tracking algorithm for simulating chemical reactions among diffusing molecules

    SciTech Connect

    Gillespie, Daniel T. Gillespie, Carol A.; Seitaridou, Effrosyni

    2014-12-21

    Simulating the evolution of a chemically reacting system using the bimolecular propensity function, as is done by the stochastic simulation algorithm and its reaction-diffusion extension, entails making statistically inspired guesses as to where the reactant molecules are at any given time. Those guesses will be physically justified if the system is dilute and well-mixed in the reactant molecules. Otherwise, an accurate simulation will require the extra effort and expense of keeping track of the positions of the reactant molecules as the system evolves. One molecule-tracking algorithm that pays careful attention to the physics of molecular diffusion is the enhanced Green's function reaction dynamics (eGFRD) of Takahashi, Tănase-Nicola, and ten Wolde [Proc. Natl. Acad. Sci. U.S.A. 107, 2473 (2010)]. We introduce here a molecule-tracking algorithm that has the same theoretical underpinnings and strategic aims as eGFRD, but a different implementation procedure. Called the small-voxel tracking algorithm (SVTA), it combines the well known voxel-hopping method for simulating molecular diffusion with a novel procedure for rectifying the unphysical predictions of the diffusion equation on the small spatiotemporal scale of molecular collisions. Indications are that the SVTA might be more computationally efficient than eGFRD for the problematic class of non-dilute systems. A widely applicable, user-friendly software implementation of the SVTA has yet to be developed, but we exhibit some simple examples which show that the algorithm is computationally feasible and gives plausible results.

  11. The small-voxel tracking algorithm for simulating chemical reactions among diffusing molecules

    NASA Astrophysics Data System (ADS)

    Gillespie, Daniel T.; Seitaridou, Effrosyni; Gillespie, Carol A.

    2014-12-01

    Simulating the evolution of a chemically reacting system using the bimolecular propensity function, as is done by the stochastic simulation algorithm and its reaction-diffusion extension, entails making statistically inspired guesses as to where the reactant molecules are at any given time. Those guesses will be physically justified if the system is dilute and well-mixed in the reactant molecules. Otherwise, an accurate simulation will require the extra effort and expense of keeping track of the positions of the reactant molecules as the system evolves. One molecule-tracking algorithm that pays careful attention to the physics of molecular diffusion is the enhanced Green's function reaction dynamics (eGFRD) of Takahashi, Tănase-Nicola, and ten Wolde [Proc. Natl. Acad. Sci. U.S.A. 107, 2473 (2010)]. We introduce here a molecule-tracking algorithm that has the same theoretical underpinnings and strategic aims as eGFRD, but a different implementation procedure. Called the small-voxel tracking algorithm (SVTA), it combines the well known voxel-hopping method for simulating molecular diffusion with a novel procedure for rectifying the unphysical predictions of the diffusion equation on the small spatiotemporal scale of molecular collisions. Indications are that the SVTA might be more computationally efficient than eGFRD for the problematic class of non-dilute systems. A widely applicable, user-friendly software implementation of the SVTA has yet to be developed, but we exhibit some simple examples which show that the algorithm is computationally feasible and gives plausible results.

  12. Atom ejection from a fast-ion track: A molecular-dynamics study

    SciTech Connect

    Urbassek, H.M. ); Kafemann, H. ); Johnson, R.E. )

    1994-01-01

    As a model for atom ejection from fast-ion tracks, molecular-dynamics simulations of a cylindrical track of energized particles are performed. An idealized situation is studied where every atom in a cylindrical track of radius [ital R][sub 0] is energized with energy [ital E][sub 0]. The emission yield [ital Y]([ital E][sub 0],[ital R][sub 0]) shows the existence of two ejection regimes. If the particle energy [ital E][sub 0] is below the sublimation energy [ital U] of the material, a threshold regime is seen in which [ital Y] rises roughly like the third power of [ital E][sub 0]; for high-energy densities [ital E][sub 0][approx gt][ital U], the yield rises much more slowly, roughly linearly. In both cases, ejected particles mostly originate from the track, rather than from its surroundings, and from the first or the first few monolayers. The behavior found is interpreted here in terms of emission due to a pressure-driven jet (linear regime) or due to a pressure pulse (threshold regime). These both behave differently from the often-used thermal-spike sputtering model.

  13. Adaptive control of piezoelectric fast steering mirror for high precision tracking application

    NASA Astrophysics Data System (ADS)

    Wang, Geng; Rao, Changhui

    2015-03-01

    A piezoelectric fast steering mirror (PFSM) is a complex, strong coupling nonlinear system that integrates optics, mechanics, electrics, and control. Due to the existence of hysteresis nonlinearity, mechanical resonance, and all kinds of disturbances, precise tracking control of a PFSM is a challenging task. This paper presents a comprehensive study of modeling, controller design, and simulation evaluation for a PFSM system. First a general model of a PFSM system integrating mechanical dynamics, electrical dynamics, and hysteresis nonlinearity is proposed, and then a robust adaptive controller is developed under both unknown hysteresis nonlinearities and parameter uncertainties. The parameters needed directly in the formulation of the controller are adaptively estimated. The proposed control law ensures the uniform boundedness of all signals in the closed-loop system. Furthermore, a stability analysis of the control system is performed to guarantee that the output tracking error converges to zero asymptotically. Finally, simulation tests with different motion trajectories are conducted to verify the effectiveness of the proposed method.

  14. In vivo optic nerve head biomechanics: performance testing of a three-dimensional tracking algorithm

    PubMed Central

    Girard, Michaël J. A.; Strouthidis, Nicholas G.; Desjardins, Adrien; Mari, Jean Martial; Ethier, C. Ross

    2013-01-01

    Measurement of optic nerve head (ONH) deformations could be useful in the clinical management of glaucoma. Here, we propose a novel three-dimensional tissue-tracking algorithm designed to be used in vivo. We carry out preliminary verification of the algorithm by testing its accuracy and its robustness. An algorithm based on digital volume correlation was developed to extract ONH tissue displacements from two optical coherence tomography (OCT) volumes of the ONH (undeformed and deformed). The algorithm was tested by applying artificial deformations to a baseline OCT scan while manipulating speckle noise, illumination and contrast enhancement. Tissue deformations determined by our algorithm were compared with the known (imposed) values. Errors in displacement magnitude, orientation and strain decreased with signal averaging and were 0.15 µm, 0.15° and 0.0019, respectively (for optimized algorithm parameters). Previous computational work suggests that these errors are acceptable to provide in vivo characterization of ONH biomechanics. Our algorithm is robust to OCT speckle noise as well as to changes in illumination conditions, and increasing signal averaging can produce better results. This algorithm has potential be used to quantify ONH three-dimensional strains in vivo, of benefit in the diagnosis and identification of risk factors in glaucoma. PMID:23883953

  15. Quadrant architecture for fast in-place algorithms

    SciTech Connect

    Besslich, P.W.; Kurowski, J.O.

    1983-10-01

    The architecture proposed is tailored to support Radix-2/sup k/ based in-place processing of pictorial data. The algorithms make use of signal-flow graphs to describe 2-dimensional in-place operations suitable for image processing. They may be executed on a general-purpose computer but may also be supported by a special parallel architecture. Major advantages of the scheme are in-place processing and parallel access to disjoint sections of memory only. A quadtree-like decomposition of the picture prevents blocking and queuing of private and common buses. 9 references.

  16. Fast Huffman encoding algorithms in MPEG-4 advanced audio coding

    NASA Astrophysics Data System (ADS)

    Brzuchalski, Grzegorz

    2014-11-01

    This paper addresses the optimisation problem of Huffman encoding in MPEG-4 Advanced Audio Coding stan- dard. At first, the Huffman encoding problem and the need of encoding two side info parameters scale factor and Huffman codebook are presented. Next, Two Loop Search, Maximum Noise Mask Ratio and Trellis Based algorithms of bit allocation are briefly described. Further, Huffman encoding optimisation are shown. New methods try to check and change scale factor bands as little as possible to estimate bitrate cost or its change. Finally, the complexity of old and new methods is calculated, compared and measured time of encoding is given.

  17. Morbidity and mortality after bilateral simultaneous total knee arthroplasty in a fast-track setting.

    PubMed

    Gromov, Kirill; Troelsen, Anders; Stahl Otte, Kristian; Ørsnes, Thue; Husted, Henrik

    2016-06-01

    Background and purpose - The safety aspects of bilateral simultaneous total knee arthroplasty (BSTKA) are still debated. In this retrospective single-center study, we investigated early morbidity and mortality following BSTKA in a modern fast-track setting. We also identified risk factors for re-admission within 90 days and for a length of stay (LOS) of more than 5 days. Patients and methods - 284 patients were selected to receive BSTKA at our institution from 2008 through 2014 in a well-described, standardized fast-track setup (Husted 2012a, b). All re-admissions within 90 days were identified and mortality rates and time until death were recorded. Transfusion rates and numbers of transfusions were also recorded. Logistic regression analysis was used to identify risk factors for re-admission within 90 days, and also for a LOS of more than 5 days. Results - 90-day mortality was 0%. 10% of the patients were re-admitted within 90 days. Median time to re-admission was 18 (3-75) days. 153 patients (54%) received postoperative blood transfusions. An ASA score of 3 was identified as an independent risk factor for re-admission within 90 days (OR = 5, 95% CI: 1.3-19) and for LOS of > 5 days (OR = 6, 95% CI: 1.6-21). Higher BMI was a weak risk factor for re-admission within 90 days. Interpretation - BSTKA in selected patients without cardiopulmonary disease in a fast-track setting appears to be safe with respect to early postoperative morbidity and mortality. Surgeons should be aware that patients with an ASA score of 3 have an increased risk of re-admission and a prolonged length of stay, while patients with higher BMI have an increased risk of re-admission following BSTKA. PMID:26823094

  18. Morbidity and mortality after bilateral simultaneous total knee arthroplasty in a fast-track setting

    PubMed Central

    Gromov, Kirill; Troelsen, Anders; Stahl Otte, Kristian; Ørsnes, Thue; Husted, Henrik

    2016-01-01

    Background and purpose The safety aspects of bilateral simultaneous total knee arthroplasty (BSTKA) are still debated. In this retrospective single-center study, we investigated early morbidity and mortality following BSTKA in a modern fast-track setting. We also identified risk factors for re-admission within 90 days and for a length of stay (LOS) of more than 5 days. Patients and methods 284 patients were selected to receive BSTKA at our institution from 2008 through 2014 in a well-described, standardized fast-track setup (Husted 2012a, b). All re-admissions within 90 days were identified and mortality rates and time until death were recorded. Transfusion rates and numbers of transfusions were also recorded. Logistic regression analysis was used to identify risk factors for re-admission within 90 days, and also for a LOS of more than 5 days. Results 90-day mortality was 0%. 10% of the patients were re-admitted within 90 days. Median time to re-admission was 18 (3–75) days. 153 patients (54%) received postoperative blood transfusions. An ASA score of 3 was identified as an independent risk factor for re-admission within 90 days (OR = 5, 95% CI: 1.3–19) and for LOS of > 5 days (OR = 6, 95% CI: 1.6–21). Higher BMI was a weak risk factor for re-admission within 90 days. Interpretation BSTKA in selected patients without cardiopulmonary disease in a fast-track setting appears to be safe with respect to early postoperative morbidity and mortality. Surgeons should be aware that patients with an ASA score of 3 have an increased risk of re-admission and a prolonged length of stay, while patients with higher BMI have an increased risk of re-admission following BSTKA. PMID:26823094

  19. "Fast-Tracking": Ain't No Golden Parachute So Don't Slide off the Rainbow.

    ERIC Educational Resources Information Center

    Newburger, Craig; Butler, Jerry

    Awareness of the corporate cultural phenomenon of fast-tracking, a process whereby executives are advanced within and among organizations, should assist communication students and practicing professionals to become more effective corporate communicators. A critical distinction between self-directed fast-trackers and their corporately-sanctioned…

  20. Efficient parallel algorithm for statistical ion track simulations in crystalline materials

    NASA Astrophysics Data System (ADS)

    Jeon, Byoungseon; Grønbech-Jensen, Niels

    2009-02-01

    We present an efficient parallel algorithm for statistical Molecular Dynamics simulations of ion tracks in solids. The method is based on the Rare Event Enhanced Domain following Molecular Dynamics (REED-MD) algorithm, which has been successfully applied to studies of, e.g., ion implantation into crystalline semiconductor wafers. We discuss the strategies for parallelizing the method, and we settle on a host-client type polling scheme in which a multiple of asynchronous processors are continuously fed to the host, which, in turn, distributes the resulting feed-back information to the clients. This real-time feed-back consists of, e.g., cumulative damage information or statistics updates necessary for the cloning in the rare event algorithm. We finally demonstrate the algorithm for radiation effects in a nuclear oxide fuel, and we show the balanced parallel approach with high parallel efficiency in multiple processor configurations.

  1. A steady tracking technology adopted to fast FH/BPSK signal under satellite channel

    NASA Astrophysics Data System (ADS)

    Guo, SuLi; Lou, Zhigang; Wang, XiDuo; Xia, ShuangZhi

    2015-07-01

    In order to survive under the conditions with great jamming and interference, fast frequency hopped signal are employed in satellite communication system. This paper discusses the nonlinear phases induced by the equipment and atmosphere, and their influence on the FFH/BPSK tracking loop. Two methods are developed including compensating phase which is based on channel estimation and compensating Doppler frequency based on velocity normalization. Simulation results for a real circuit with proper parameters shows that the degradation due to the demodulation of frequency-hopped is only a fraction of one dB in an AWGN environment under satellite channel.

  2. Fast track lunar NTR systems assessment for the First Lunar Outpost and its evolvability to Mars

    NASA Technical Reports Server (NTRS)

    Borowski, Stanley K.; Alexander, Stephen W.

    1992-01-01

    The objectives of the 'fast track' lunar Nuclear Thermal Rocket (NTR) analysis are to quantify necessary engine/stage characteristics to perform NASA's 'First Lunar Outpost' scenario and to assess the potential for evolution to Mars mission applications. By developing NTR/stage technologies for use in NASA's 'First Lunar Outpost' scenario, NASA will make a major down payment on the key components needed for the follow-on Mars Space Transportation System. A faster, cheaper approach to overall lunar/Mars exploration is expected.

  3. A fast algorithm for the simulation of arterial pulse waves

    NASA Astrophysics Data System (ADS)

    Du, Tao; Hu, Dan; Cai, David

    2016-06-01

    One-dimensional models have been widely used in studies of the propagation of blood pulse waves in large arterial trees. Under a periodic driving of the heartbeat, traditional numerical methods, such as the Lax-Wendroff method, are employed to obtain asymptotic periodic solutions at large times. However, these methods are severely constrained by the CFL condition due to large pulse wave speed. In this work, we develop a new numerical algorithm to overcome this constraint. First, we reformulate the model system of pulse wave propagation using a set of Riemann variables and derive a new form of boundary conditions at the inlet, the outlets, and the bifurcation points of the arterial tree. The new form of the boundary conditions enables us to design a convergent iterative method to enforce the boundary conditions. Then, after exchanging the spatial and temporal coordinates of the model system, we apply the Lax-Wendroff method in the exchanged coordinate system, which turns the large pulse wave speed from a liability to a benefit, to solve the wave equation in each artery of the model arterial system. Our numerical studies show that our new algorithm is stable and can perform ∼15 times faster than the traditional implementation of the Lax-Wendroff method under the requirement that the relative numerical error of blood pressure be smaller than one percent, which is much smaller than the modeling error.

  4. Fast Quantum Algorithm for Predicting Descriptive Statistics of Stochastic Processes

    NASA Technical Reports Server (NTRS)

    Williams Colin P.

    1999-01-01

    Stochastic processes are used as a modeling tool in several sub-fields of physics, biology, and finance. Analytic understanding of the long term behavior of such processes is only tractable for very simple types of stochastic processes such as Markovian processes. However, in real world applications more complex stochastic processes often arise. In physics, the complicating factor might be nonlinearities; in biology it might be memory effects; and in finance is might be the non-random intentional behavior of participants in a market. In the absence of analytic insight, one is forced to understand these more complex stochastic processes via numerical simulation techniques. In this paper we present a quantum algorithm for performing such simulations. In particular, we show how a quantum algorithm can predict arbitrary descriptive statistics (moments) of N-step stochastic processes in just O(square root of N) time. That is, the quantum complexity is the square root of the classical complexity for performing such simulations. This is a significant speedup in comparison to the current state of the art.

  5. Fast algorithms for glassy materials: methods and explorations

    NASA Astrophysics Data System (ADS)

    Middleton, A. Alan

    2014-03-01

    Glassy materials with frozen disorder, including random magnets such as spin glasses and interfaces in disordered materials, exhibit striking non-equilibrium behavior such as the ability to store a history of external parameters (memory). Precisely due to their glassy nature, direct simulation of models of these materials is very slow. In some fortunate cases, however, algorithms exist that exactly compute thermodynamic quantities. Such cases include spin glasses in two dimensions and interfaces and random field magnets in arbitrary dimensions at zero temperature. Using algorithms built using ideas developed by computer scientists and mathematicians, one can even directly sample equilibrium configurations in very large systems, as if one picked the configurations out of a ``hat'' of all configurations weighted by their Boltzmann factors. This talk will provide some of the background for these methods and discuss the connections between physics and computer science, as used by a number of groups. Recent applications of these methods to investigating phase transitions in glassy materials and to answering qualitative questions about the free energy landscape and memory effects will be discussed. This work was supported in part by NSF grant DMR-1006731. Creighton Thomas and David Huse also contributed to much of the work to be presented.

  6. An Improved Interacting Multiple Model Filtering Algorithm Based on the Cubature Kalman Filter for Maneuvering Target Tracking.

    PubMed

    Zhu, Wei; Wang, Wei; Yuan, Gannan

    2016-01-01

    In order to improve the tracking accuracy, model estimation accuracy and quick response of multiple model maneuvering target tracking, the interacting multiple models five degree cubature Kalman filter (IMM5CKF) is proposed in this paper. In the proposed algorithm, the interacting multiple models (IMM) algorithm processes all the models through a Markov Chain to simultaneously enhance the model tracking accuracy of target tracking. Then a five degree cubature Kalman filter (5CKF) evaluates the surface integral by a higher but deterministic odd ordered spherical cubature rule to improve the tracking accuracy and the model switch sensitivity of the IMM algorithm. Finally, the simulation results demonstrate that the proposed algorithm exhibits quick and smooth switching when disposing different maneuver models, and it also performs better than the interacting multiple models cubature Kalman filter (IMMCKF), interacting multiple models unscented Kalman filter (IMMUKF), 5CKF and the optimal mode transition matrix IMM (OMTM-IMM). PMID:27258285

  7. An Improved Interacting Multiple Model Filtering Algorithm Based on the Cubature Kalman Filter for Maneuvering Target Tracking

    PubMed Central

    Zhu, Wei; Wang, Wei; Yuan, Gannan

    2016-01-01

    In order to improve the tracking accuracy, model estimation accuracy and quick response of multiple model maneuvering target tracking, the interacting multiple models five degree cubature Kalman filter (IMM5CKF) is proposed in this paper. In the proposed algorithm, the interacting multiple models (IMM) algorithm processes all the models through a Markov Chain to simultaneously enhance the model tracking accuracy of target tracking. Then a five degree cubature Kalman filter (5CKF) evaluates the surface integral by a higher but deterministic odd ordered spherical cubature rule to improve the tracking accuracy and the model switch sensitivity of the IMM algorithm. Finally, the simulation results demonstrate that the proposed algorithm exhibits quick and smooth switching when disposing different maneuver models, and it also performs better than the interacting multiple models cubature Kalman filter (IMMCKF), interacting multiple models unscented Kalman filter (IMMUKF), 5CKF and the optimal mode transition matrix IMM (OMTM-IMM). PMID:27258285

  8. Fast computation of Lagrangian coherent structures: algorithms and error analysis

    NASA Astrophysics Data System (ADS)

    Brunton, Steven; Rowley, Clarence

    2009-11-01

    This work investigates a number of efficient methods for computing finite time Lyapunov exponent (FTLE) fields in unsteady flows by approximating the particle flow map and eliminating redundant particle integrations in neighboring flow maps. Ridges of the FTLE fields are Lagrangian coherent structures (LCS) and provide an unsteady analogue of invariant manifolds from dynamical systems theory. The fast methods fall into two categories, unidirectional and bidirectional, depending on whether flow maps in one or both time directions are composed to form an approximate flow map. An error analysis is presented which shows that the unidirectional methods are accurate while the bidirectional methods have significant error which is aligned with the opposite time coherent structures. This relies on the fact that material from the positive time LCS attracts onto the negative time LCS near time-dependent saddle points.

  9. "Mtrack 1.0": A multi-vehicle, deterministic tracking algorithm

    SciTech Connect

    Carrano, C J

    2008-05-22

    As overhead persistent surveillance sensors become more capable at acquiring wide-field image sequences for longer time-spans, the need to exploit such data becomes ever greater. A desirable use of such sensors is to be able to track all the observable vehicles while they persist in the imagery. Typically, this imagery is characterized by lower resolutions (e.g. >= 0.5 m/pixel ) and lower frame rates (e.g. {approx} few Hz). We describe our initial implementation of a multiple-vehicle tracking algorithm for overhead persistent surveillance imagery. Subsequent reports will then present results of applying this tracker to specific persistent surveillance imagery as well as algorithm improvements and extensions for dealing with wider-field imagery.

  10. Residual Elimination Algorithm Enhancements to Improve Foot Motion Tracking During Forward Dynamic Simulations of Gait.

    PubMed

    Jackson, Jennifer N; Hass, Chris J; Fregly, Benjamin J

    2015-11-01

    Patient-specific gait optimizations capable of predicting post-treatment changes in joint motions and loads could improve treatment design for gait-related disorders. To maximize potential clinical utility, such optimizations should utilize full-body three-dimensional patient-specific musculoskeletal models, generate dynamically consistent gait motions that reproduce pretreatment marker measurements closely, and achieve accurate foot motion tracking to permit deformable foot-ground contact modeling. This study enhances an existing residual elimination algorithm (REA) Remy, C. D., and Thelen, D. G., 2009, “Optimal Estimation of Dynamically Consistent Kinematics and Kinetics for Forward Dynamic Simulation of Gait,” ASME J. Biomech. Eng., 131(3), p. 031005) to achieve all three requirements within a single gait optimization framework. We investigated four primary enhancements to the original REA: (1) manual modification of tracked marker weights, (2) automatic modification of tracked joint acceleration curves, (3) automatic modification of algorithm feedback gains, and (4) automatic calibration of model joint and inertial parameter values. We evaluated the enhanced REA using a full-body three-dimensional dynamic skeletal model and movement data collected from a subject who performed four distinct gait patterns: walking, marching, running, and bounding. When all four enhancements were implemented together, the enhanced REA achieved dynamic consistency with lower marker tracking errors for all segments, especially the feet (mean root-mean-square (RMS) errors of 3.1 versus 18.4 mm), compared to the original REA. When the enhancements were implemented separately and in combinations, the most important one was automatic modification of tracked joint acceleration curves, while the least important enhancement was automatic modification of algorithm feedback gains. The enhanced REA provides a framework for future gait optimization studies that seek to predict subject

  11. Compiling fast partial derivatives of functions given by algorithms

    SciTech Connect

    Speelpenning, B.

    1980-01-01

    If the gradient of the function y = f(x/sub 1/,..., x/sub n/) is desired, where f is given by an algoritym Af(x, n, y), most numerical analysts will use numerical differencing. This is a sampling scheme that approximates derivatives by the slope of secants in closely spaced points. Symbolic methods that make full use of the program text of Af should be able to come up with a better way to evaluate the gradient of F. The system Jake described produces gradients significantly faster than numerical differencing. Jake can handle algorithms Af with arbitrary flow of control. Measurements performed on one particular machine suggest that Jake is faster than numerical differencing for n > 8. Somewhat weaker results were obtained for the problem of computing Jacobians of arbitrary shape.

  12. Probe Vehicle Track-Matching Algorithm Based on Spatial Semantic Features

    NASA Astrophysics Data System (ADS)

    Luo, Y.; Song, X.; Zheng, L.; Yang, C.; Yu, M.; Sun, M.

    2015-07-01

    The matching of GPS received locations to roads is challenging. Traditional matching method is based on the position of the GPS receiver, the vehicle position and vehicle behavior near the receiving time. However, for probe vehicle trajectories, the sampling interval is too sparse and there is a poor correlation between adjacent sampling points, so it cannot partition the GPS noise through the historical positions. For the data mining of probe vehicle tracks based on spatial semantics, the matching is learned from the traditional electronic navigation map matching, and it is proposed that the probe vehicle track matching algorithm is based on spatial semantic features. Experimental results show that the proposed global-path matching method gets a good matching results, and restores the true path through the probe vehicle track.

  13. Ultra-fast fluence optimization for beam angle selection algorithms

    NASA Astrophysics Data System (ADS)

    Bangert, M.; Ziegenhein, P.; Oelfke, U.

    2014-03-01

    Beam angle selection (BAS) including fluence optimization (FO) is among the most extensive computational tasks in radiotherapy. Precomputed dose influence data (DID) of all considered beam orientations (up to 100 GB for complex cases) has to be handled in the main memory and repeated FOs are required for different beam ensembles. In this paper, the authors describe concepts accelerating FO for BAS algorithms using off-the-shelf multiprocessor workstations. The FO runtime is not dominated by the arithmetic load of the CPUs but by the transportation of DID from the RAM to the CPUs. On multiprocessor workstations, however, the speed of data transportation from the main memory to the CPUs is non-uniform across the RAM; every CPU has a dedicated memory location (node) with minimum access time. We apply a thread node binding strategy to ensure that CPUs only access DID from their preferred node. Ideal load balancing for arbitrary beam ensembles is guaranteed by distributing the DID of every candidate beam equally to all nodes. Furthermore we use a custom sorting scheme of the DID to minimize the overall data transportation. The framework is implemented on an AMD Opteron workstation. One FO iteration comprising dose, objective function, and gradient calculation takes between 0.010 s (9 beams, skull, 0.23 GB DID) and 0.070 s (9 beams, abdomen, 1.50 GB DID). Our overall FO time is < 1 s for small cases, larger cases take ~ 4 s. BAS runs including FOs for 1000 different beam ensembles take ~ 15-70 min, depending on the treatment site. This enables an efficient clinical evaluation of different BAS algorithms.

  14. [An improved fast algorithm for ray casting volume rendering of medical images].

    PubMed

    Tao, Ling; Wang, Huina; Tian, Zhiliang

    2006-10-01

    Ray casting algorithm can obtain better quality images in volume rendering, however, it presents some problems such as powerful computing capacity and slow rendering velocity. Therefore, a new fast algorithm of ray casting volume rendering is proposed in this paper. This algorithm reduces matrix computation by the matrix transformation characteristics of re-sampling points in two coordinate system, so re-sampled computational process is accelerated. By extending the Bresenham algorithm to three dimension and utilizing boundary box technique, this algorithm avoids the sampling in empty voxel and greatly improves the efficiency of ray casting. The experiment results show that the improved acceleration algorithm can produce the required quality images, at the same time reduces the total operations remarkably, and speeds up the volume rendering. PMID:17121341

  15. PTM Along Track Algorithm to Maintain Spacing During Same Direction Pair-Wise Trajectory Management Operations

    NASA Technical Reports Server (NTRS)

    Carreno, Victor A.

    2015-01-01

    Pair-wise Trajectory Management (PTM) is a cockpit based delegated responsibility separation standard. When an air traffic service provider gives a PTM clearance to an aircraft and the flight crew accepts the clearance, the flight crew will maintain spacing and separation from a designated aircraft. A PTM along track algorithm will receive state information from the designated aircraft and from the own ship to produce speed guidance for the flight crew to maintain spacing and separation

  16. Evaluation of the Jonker-Volgenant-Castanon (JVC) assignment algorithm for track association

    NASA Astrophysics Data System (ADS)

    Malkoff, Donald B.

    1997-07-01

    The Jonker-Volgenant-Castanon (JVC) assignment algorithm was used by Lockheed Martin Advanced Technology Laboratories (ATL) for track association in the Rotorcraft Pilot's Associate (RPA) program. RPA is Army Aviation's largest science and technology program, involving an integrated hardware/software system approach for a next generation helicopter containing advanced sensor equipments and applying artificial intelligence `associate' technologies. ATL is responsible for the multisensor, multitarget, onboard/offboard track fusion. McDonnell Douglas Helicopter Systems is the prime contractor and Lockheed Martin Federal Systems is responsible for developing much of the cognitive decision aiding and controls-and-displays subsystems. RPA is scheduled for flight testing beginning in 1997. RPA is unique in requiring real-time tracking and fusion for large numbers of highly-maneuverable ground (and air) targets in a target-dense environment. It uses diverse sensors and is concerned with a large area of interest. Target class and identification data is tightly integrated with spatial and kinematic data throughout the processing. Because of platform constraints, processing hardware for track fusion was quite limited. No previous experience using JVC in this type environment had been reported. ATL performed extensive testing of the JVC, concentrating on error rates and run- times under a variety of conditions. These included wide ranging numbers and types of targets, sensor uncertainties, target attributes, differing degrees of target maneuverability, and diverse combinations of sensors. Testing utilized Monte Carlo approaches, as well as many kinds of challenging scenarios. Comparisons were made with a nearest-neighbor algorithm and a new, proprietary algorithm (the `Competition' algorithm). The JVC proved to be an excellent choice for the RPA environment, providing a good balance between speed of operation and accuracy of results.

  17. A multi-region algorithm for markerless beam's-eye view lung tumor tracking

    NASA Astrophysics Data System (ADS)

    Rottmann, J.; Aristophanous, M.; Chen, A.; Court, L.; Berbeco, R.

    2010-09-01

    Methods that allow online lung tumor tracking during radiotherapy are desirable for a variety of applications that have the potential to vastly improve treatment accuracy, dose conformity and sparing of healthy tissue. Several publications have proposed the use of an on-board kV x-ray imager to assess the tumor location during treatment. However, there is some concern that this strategy may expose the patient to a significant amount of additional dose over the course of a typical radiotherapy treatment. In this paper we present an algorithm that utilizes the on-board portal imager of the treatment machine to track lung tumors. This does not expose the patient to additional dose, but is somewhat more challenging as the quality of portal images is inferior when compared to kV x-ray images. To quantify the performance of the proposed algorithm we retrospectively applied it to portal image sequences retrieved from a dynamic chest phantom study and an SBRT treatment performed at our institution. The results were compared to manual tracking by an expert. For the phantom data the tracking error was found to be smaller than 1 mm and for the patient data smaller than 2 mm, which was in the same range as the uncertainty of the gold standard.

  18. SIML: A Fast SIMD Algorithm for Calculating LINGO Chemical Similarities on GPUs and CPUs

    PubMed Central

    Haque, Imran S.; Walters, W. Patrick

    2010-01-01

    LINGOs are a holographic measure of chemical similarity based on text comparison of SMILES strings. We present a new algorithm for calculating LINGO similarities amenable to parallelization on SIMD architectures (such as GPUs and vector units of modern CPUs). We show that it is nearly 3 times as fast as existing algorithms on a CPU, and over 80 times faster than existing methods when run on a GPU. PMID:20218693

  19. A preliminary report on the development of MATLAB tensor classes for fast algorithm prototyping.

    SciTech Connect

    Bader, Brett William; Kolda, Tamara Gibson

    2004-07-01

    We describe three MATLAB classes for manipulating tensors in order to allow fast algorithm prototyping. A tensor is a multidimensional or N-way array. We present a tensor class for manipulating tensors which allows for tensor multiplication and 'matricization.' We have further added two classes for representing tensors in decomposed format: cp{_}tensor and tucker{_}tensor. We demonstrate the use of these classes by implementing several algorithms that have appeared in the literature.

  20. Track extraction of moving targets in astronomical images based on the algorithm of NCST-PCNN

    NASA Astrophysics Data System (ADS)

    Du, Lin; Sun, Huayan; Zhang, Tinghua; Xu, Taohu

    2015-10-01

    Space targets in astronomical images such as spacecraft and space debris are always in the low level of brightness and hold a small amount of pixels, which are difficult to distinguish from fixed stars. Because of the difficulties of space target information extraction, dynamic object monitoring plays an important role in the military, aerospace and other fields, track extraction of moving targets in short-exposure astronomical images holds great significance. Firstly, capture the interesting stars by region growing method in the sequence of short-exposure images and extract the barycenter of interesting star by gray weighted method. Secondly, use adaptive threshold method to remove the error matching points and register the sequence of astronomical images. Thirdly, fuse the registered images by NCST-PCNN image fusion algorithm to hold the energy of stars in the images. Fourthly, get the difference of fused star image and final star image by subtraction of brightness value in the two images, the interesting possible moving targets will be captured by energy accumulation method. Finally, the track of moving target in astronomical images will be extracted by judging the accuracy of moving targets by track association and excluding the false moving targets. The algorithm proposed in the paper can effectively extract the moving target which is added artificially from three images or four images respectively, which verifies the effectiveness of the algorithm.

  1. Fiber tracking algorithm in combined PIV/PTV measurement of fiber suspension flow

    NASA Astrophysics Data System (ADS)

    Hoseini, Afshin Abbasi; Zavareh, Zahra; Lundell, Fredrik; Anderson, Helge I.

    2013-10-01

    A new algorithm for fiber tracking in combined PIV/PTV measurement of fiber suspension flow is proposed based on SOM neural network and is examined by synthetic images of fibers showing 2D suspension flows. There is a new idea in the algorithm to take the orientation of fibers into account for matching as well as their position. In two-phase PIV measurements of fiber-laded suspension flows, fiber tracking has a key role together with PIV measurement of fluid phase. The essential parts of fiber tracking are to correctly identify and match fibers in successive images. The development of a method in order to determine the position and orientation of fibers using steerable filter with a reasonable accuracy have already been done, [3]. The present study is concentrated in the development of an algorithm for pairing fibers in consecutive images. The method used is based on the SOM neural network that finds most likely matching link in images on the basis of feature extraction and clustering. The fundamental concept is finding the corresponding fibers with the nearest characteristics, position and angle in images. It improves not only the robustness against loss-of-pair fibers between two image frames but also reliable matching at large numbers of dispersed fibers image using one more characteristics of fibers in image, namely their orientation, in addition to their coordinate vector.

  2. Four-dimensional IMRT treatment planning using a DMLC motion-tracking algorithm

    NASA Astrophysics Data System (ADS)

    Suh, Yelin; Sawant, Amit; Venkat, Raghu; Keall, Paul J.

    2009-06-01

    The purpose of this study is to develop a four-dimensional (4D) intensity-modulated radiation therapy (IMRT) treatment-planning method by modifying and applying a dynamic multileaf collimator (DMLC) motion-tracking algorithm. The 4D radiotherapy treatment scenario investigated is to obtain a 4D treatment plan based on a 4D computed tomography (CT) planning scan and to have the delivery flexible enough to account for changes in tumor position during treatment delivery. For each of 4D CT planning scans from 12 lung cancer patients, a reference phase plan was created; with its MLC leaf positions and three-dimensional (3D) tumor motion, the DMLC motion-tracking algorithm generated MLC leaf sequences for the plans of other respiratory phases. Then, a deformable dose-summed 4D plan was created by merging the leaf sequences of individual phase plans. Individual phase plans, as well as the deformable dose-summed 4D plan, are similar for each patient, indicating that this method is dosimetrically robust to the variations of fractional time spent in respiratory phases on a given 4D CT planning scan. The 4D IMRT treatment-planning method utilizing the DMLC motion-tracking algorithm explicitly accounts for 3D tumor motion and thus hysteresis and nonlinear motion, and is deliverable on a linear accelerator.

  3. Fast algorithm for calculation of the moving tsunami wave height

    NASA Astrophysics Data System (ADS)

    Krivorotko, Olga; Kabanikhin, Sergey

    2014-05-01

    One of the most urgent problems of mathematical tsunami modeling is estimation of a tsunami wave height while a wave approaches to the coastal zone. There are two methods for solving this problem, namely, Airy-Green formula in one-dimensional case ° --- S(x) = S(0) 4 H(0)/H (x), and numerical solution of an initial-boundary value problem for linear shallow water equations ( { ηtt = div (gH (x,y)gradη), (x,y,t) ∈ ΩT := Ω ×(0,T); ( η|t=0 = q(x,y), ηt|t=0 = 0, (x,y ) ∈ Ω := (0,Lx)× (0,Ly ); (1) η|δΩT = 0. Here η(x,y,t) is the free water surface vertical displacement, H(x,y) is the depth at point (x,y), q(x,y) is the initial amplitude of a tsunami wave, S(x) is a moving tsunami wave height at point x. The main difficulty problem of tsunami modeling is a very big size of the computational domain ΩT. The calculation of the function η(x,y,t) of three variables in ΩT requires large computing resources. We construct a new algorithm to solve numerically the problem of determining the moving tsunami wave height which is based on kinematic-type approach and analytical representation of fundamental solution (2). The wave is supposed to be generated by the seismic fault of the bottom η(x,y,0) = g(y) ·θ(x), where θ(x) is a Heaviside theta-function. Let τ(x,y) be a solution of the eikonal equation 1 τ2x +τ2y = --, gH (x,y) satisfying initial conditions τ(0,y) = 0 and τx(0,y) = (gH (0,y))-1/2. Introducing new variables and new functions: ° -- z = τ(x,y), u(z,y,t) = ηt(x,y,t), b(z,y) = gH(x,y). We obtain an initial-boundary value problem in new variables from (1) ( 2 2 (2 bz- ) { utt = uzz + b uyy + 2b τyuzy + b(τxx + τyy) + 2b + 2bbyτy uz+ ( +2b(bzτy + by)uy, z,y- >2 0,t > 0,2 -1/2 u|t 0,t > 0. Then after some mathematical transformation we get the structure of the function u(x,y,t) in the form u(z,y,t) = S(z,y)·θ(t - z) + ˜u(z,y,t). (2) Here Å©(z,y,t) is a smooth function, S(z,y) is the solution of the problem: { S + b2τ S + (1b2(τ +

  4. Fast Estimation of Defect Profiles from the Magnetic Flux Leakage Signal Based on a Multi-Power Affine Projection Algorithm

    PubMed Central

    Han, Wenhua; Shen, Xiaohui; Xu, Jun; Wang, Ping; Tian, Guiyun; Wu, Zhengyang

    2014-01-01

    Magnetic flux leakage (MFL) inspection is one of the most important and sensitive nondestructive testing approaches. For online MFL inspection of a long-range railway track or oil pipeline, a fast and effective defect profile estimating method based on a multi-power affine projection algorithm (MAPA) is proposed, where the depth of a sampling point is related with not only the MFL signals before it, but also the ones after it, and all of the sampling points related to one point appear as serials or multi-power. Defect profile estimation has two steps: regulating a weight vector in an MAPA filter and estimating a defect profile with the MAPA filter. Both simulation and experimental data are used to test the performance of the proposed method. The results demonstrate that the proposed method exhibits high speed while maintaining the estimated profiles clearly close to the desired ones in a noisy environment, thereby meeting the demand of accurate online inspection. PMID:25192314

  5. Fast estimation of defect profiles from the magnetic flux leakage signal based on a multi-power affine projection algorithm.

    PubMed

    Han, Wenhua; Shen, Xiaohui; Xu, Jun; Wang, Ping; Tian, Guiyun; Wu, Zhengyang

    2014-01-01

    Magnetic flux leakage (MFL) inspection is one of the most important and sensitive nondestructive testing approaches. For online MFL inspection of a long-range railway track or oil pipeline, a fast and effective defect profile estimating method based on a multi-power affine projection algorithm (MAPA) is proposed, where the depth of a sampling point is related with not only the MFL signals before it, but also the ones after it, and all of the sampling points related to one point appear as serials or multi-power. Defect profile estimation has two steps: regulating a weight vector in an MAPA filter and estimating a defect profile with the MAPA filter. Both simulation and experimental data are used to test the performance of the proposed method. The results demonstrate that the proposed method exhibits high speed while maintaining the estimated profiles clearly close to the desired ones in a noisy environment, thereby meeting the demand of accurate online inspection. PMID:25192314

  6. Fast-track program in laparoscopic liver surgery: Theory or fact?

    PubMed Central

    Sánchez-Pérez, Belinda; Aranda-Narváez, José Manuel; Suárez-Muñoz, Miguel Angel; elAdel-delFresno, Moises; Fernández-Aguilar, José Luis; Pérez-Daga, Jose Antonio; Pulido-Roa, Ysabel; Santoyo-Santoyo, Julio

    2012-01-01

    AIM: To analyze our results after the introduction of a fast-track (FT) program after laparoscopic liver surgery in our Hepatobiliarypancreatic Unit. METHODS: All patients (43) undergoing laparoscopic liver surgery between March 2004 and March 2010 were included and divided into two consecutive groups: Control group (CG) from March 2004 until December 2006 with traditional perioperative cares (17 patients) and fast-track group (FTG) from January 2007 until March 2010 with FT program cares (26 patients). Primary endpoint was the influence of the program on the postoperative stay, the amount of re-admissions, morbidity and mortality. Secondarily we considered duration of surgery, use of drains, conversion to open surgery, intensive cares needs and transfusion. RESULTS: Both groups were homogeneous in age and sex. No differences in technique, time of surgery or conversion to open surgery were found, but more malignant diseases were operated in the FTG, and then transfusions were higher in FTG. Readmissions and morbidity were similar in both groups, without mortality. Postoperative stay was similar, with a median of 3 for CG vs 2.5 for FTG. However, the 80.8% of patients from FTG left the hospital within the first 3 d after surgery (58.8% for CG). CONCLUSION: The introduction of a FT program after laparoscopic liver surgery improves the recovery of patients without increasing complications or re-admissions, which leads to a reduction of the stay and costs. PMID:23493957

  7. Fast track anesthesia for liver transplantation: Review of the current practice.

    PubMed

    Aniskevich, Stephen; Pai, Sher-Lu

    2015-09-18

    Historically, patients undergoing liver transplantation were left intubated and extubated in the intensive care unit (ICU) after a period of recovery. Proponents of this practice argued that these patients were critically ill and need time to be properly optimized from a physiological and pain standpoint prior to extubation. Recently, there has been a growing movement toward early extubation in transplant centers worldwide. Initially fueled by research into early extubation following cardiac surgery, extubation in the operating room or soon after arrival to the ICU, has been shown to be safe with proper patient selection. Additionally, as experience at determining appropriate candidates has improved, some institutions have developed systems to allow select patients to bypass the ICU entirely and be admitted to the surgical ward after transplant. We discuss the history of early extubation and the arguments in favor and against fast track anesthesia. We also described our practice of fast track anesthesia at Mayo Clinic Florida, in which, we extubate approximately 60% of our patients in the operating room and send them to the surgical ward after a period of time in the post anesthesia recovery unit. PMID:26380654

  8. Detailed Evaluation of Five 3D Speckle Tracking Algorithms Using Synthetic Echocardiographic Recordings.

    PubMed

    Alessandrini, Martino; Heyde, Brecht; Queiros, Sandro; Cygan, Szymon; Zontak, Maria; Somphone, Oudom; Bernard, Olivier; Sermesant, Maxime; Delingette, Herve; Barbosa, Daniel; De Craene, Mathieu; ODonnell, Matthew; Dhooge, Jan

    2016-08-01

    A plethora of techniques for cardiac deformation imaging with 3D ultrasound, typically referred to as 3D speckle tracking techniques, are available from academia and industry. Although the benefits of single methods over alternative ones have been reported in separate publications, the intrinsic differences in the data and definitions used makes it hard to compare the relative performance of different solutions. To address this issue, we have recently proposed a framework to simulate realistic 3D echocardiographic recordings and used it to generate a common set of ground-truth data for 3D speckle tracking algorithms, which was made available online. The aim of this study was therefore to use the newly developed database to contrast non-commercial speckle tracking solutions from research groups with leading expertise in the field. The five techniques involved cover the most representative families of existing approaches, namely block-matching, radio-frequency tracking, optical flow and elastic image registration. The techniques were contrasted in terms of tracking and strain accuracy. The feasibility of the obtained strain measurements to diagnose pathology was also tested for ischemia and dyssynchrony. PMID:26960220

  9. Speed-up hyperspheres homotopic path tracking algorithm for PWL circuits simulations.

    PubMed

    Ramirez-Pinero, A; Vazquez-Leal, H; Jimenez-Fernandez, V M; Sedighi, H M; Rashidi, M M; Filobello-Nino, U; Castaneda-Sheissa, R; Huerta-Chua, J; Sarmiento-Reyes, L A; Laguna-Camacho, J R; Castro-Gonzalez, F

    2016-01-01

    In the present work, we introduce an improved version of the hyperspheres path tracking method adapted for piecewise linear (PWL) circuits. This enhanced version takes advantage of the PWL characteristics from the homotopic curve, achieving faster path tracking and improving the performance of the homotopy continuation method (HCM). Faster computing time allows the study of complex circuits with higher complexity; the proposed method also decrease, significantly, the probability of having a diverging problem when using the Newton-Raphson method because it is applied just twice per linear region on the homotopic path. Equilibrium equations of the studied circuits are obtained applying the modified nodal analysis; this method allows to propose an algorithm for nonlinear circuit analysis. Besides, a starting point criteria is proposed to obtain better performance of the HCM and a technique for avoiding the reversion phenomenon is also proposed. To prove the efficiency of the path tracking method, several cases study with bipolar (BJT) and CMOS transistors are provided. Simulation results show that the proposed approach can be up to twelve times faster than the original path tracking method and also helps to avoid several reversion cases that appears when original hyperspheres path tracking scheme was employed. PMID:27386338

  10. A new fast scanning system for the measurement of large angle tracks in nuclear emulsions

    NASA Astrophysics Data System (ADS)

    Alexandrov, A.; Buonaura, A.; Consiglio, L.; D'Ambrosio, N.; De Lellis, G.; Di Crescenzo, A.; Di Marco, N.; Galati, G.; Lauria, A.; Montesi, M. C.; Pupilli, F.; Shchedrina, T.; Tioukov, V.; Vladymyrov, M.

    2015-11-01

    Nuclear emulsions have been widely used in particle physics to identify new particles through the observation of their decays thanks to their unique spatial resolution. Nevertheless, before the advent of automatic scanning systems, the emulsion analysis was very demanding in terms of well trained manpower. Due to this reason, they were gradually replaced by electronic detectors, until the '90s, when automatic microscopes started to be developed in Japan and in Europe. Automatic scanning was essential to conceive large scale emulsion-based neutrino experiments like CHORUS, DONUT and OPERA. Standard scanning systems have been initially designed to recognize tracks within a limited angular acceptance (θ lesssim 30°) where θ is the track angle with respect to a line perpendicular to the emulsion plane. In this paper we describe the implementation of a novel fast automatic scanning system aimed at extending the track recognition to the full angular range and improving the present scanning speed. Indeed, nuclear emulsions do not have any intrinsic limit to detect particle direction. Such improvement opens new perspectives to use nuclear emulsions in several fields in addition to large scale neutrino experiments, like muon radiography, medical applications and dark matter directional detection.

  11. An evolutionary computation based algorithm for calculating solar differential rotation by automatic tracking of coronal bright points

    NASA Astrophysics Data System (ADS)

    Shahamatnia, Ehsan; Dorotovič, Ivan; Fonseca, Jose M.; Ribeiro, Rita A.

    2016-03-01

    Developing specialized software tools is essential to support studies of solar activity evolution. With new space missions such as Solar Dynamics Observatory (SDO), solar images are being produced in unprecedented volumes. To capitalize on that huge data availability, the scientific community needs a new generation of software tools for automatic and efficient data processing. In this paper a prototype of a modular framework for solar feature detection, characterization, and tracking is presented. To develop an efficient system capable of automatic solar feature tracking and measuring, a hybrid approach combining specialized image processing, evolutionary optimization, and soft computing algorithms is being followed. The specialized hybrid algorithm for tracking solar features allows automatic feature tracking while gathering characterization details about the tracked features. The hybrid algorithm takes advantages of the snake model, a specialized image processing algorithm widely used in applications such as boundary delineation, image segmentation, and object tracking. Further, it exploits the flexibility and efficiency of Particle Swarm Optimization (PSO), a stochastic population based optimization algorithm. PSO has been used successfully in a wide range of applications including combinatorial optimization, control, clustering, robotics, scheduling, and image processing and video analysis applications. The proposed tool, denoted PSO-Snake model, was already successfully tested in other works for tracking sunspots and coronal bright points. In this work, we discuss the application of the PSO-Snake algorithm for calculating the sidereal rotational angular velocity of the solar corona. To validate the results we compare them with published manual results performed by an expert.

  12. A ground track control algorithm for the Topographic Mapping Laser Altimeter (TMLA)

    NASA Technical Reports Server (NTRS)

    Blaes, V.; Mcintosh, R.; Roszman, L.; Cooley, J.

    1993-01-01

    The results of an analysis of an algorithm that will provide autonomous onboard orbit control using orbits determined with Global Positioning System (GPS) data. The algorithm uses the GPS data to (1) compute the ground track error relative to a fixed longitude grid, and (2) determine the altitude adjustment required to correct the longitude error. A program was written on a personal computer (PC) to test the concept for numerous altitudes and values of solar flux using a simplified orbit model including only the J sub 2 zonal harmonic and simple orbit decay computations. The algorithm was then implemented in a precision orbit propagation program having a full range of perturbations. The analysis showed that, even with all perturbations (including actual time histories of solar flux variation), the algorithm could effectively control the spacecraft ground track and yield more than 99 percent Earth coverage in the time required to complete one coverage cycle on the fixed grid (220 to 230 days depending on altitude and overlap allowance).

  13. Modified fast frequency acquisition via adaptive least squares algorithm

    NASA Technical Reports Server (NTRS)

    Kumar, Rajendra (Inventor)

    1992-01-01

    A method and the associated apparatus for estimating the amplitude, frequency, and phase of a signal of interest are presented. The method comprises the following steps: (1) inputting the signal of interest; (2) generating a reference signal with adjustable amplitude, frequency and phase at an output thereof; (3) mixing the signal of interest with the reference signal and a signal 90 deg out of phase with the reference signal to provide a pair of quadrature sample signals comprising respectively a difference between the signal of interest and the reference signal and a difference between the signal of interest and the signal 90 deg out of phase with the reference signal; (4) using the pair of quadrature sample signals to compute estimates of the amplitude, frequency, and phase of an error signal comprising the difference between the signal of interest and the reference signal employing a least squares estimation; (5) adjusting the amplitude, frequency, and phase of the reference signal from the numerically controlled oscillator in a manner which drives the error signal towards zero; and (6) outputting the estimates of the amplitude, frequency, and phase of the error signal in combination with the reference signal to produce a best estimate of the amplitude, frequency, and phase of the signal of interest. The preferred method includes the step of providing the error signal as a real time confidence measure as to the accuracy of the estimates wherein the closer the error signal is to zero, the higher the probability that the estimates are accurate. A matrix in the estimation algorithm provides an estimate of the variance of the estimation error.

  14. Comparing precorrected-FFT and fast multipole algorithms for solving three-dimensional potential integral equations

    SciTech Connect

    White, J.; Phillips, J.R.; Korsmeyer, T.

    1994-12-31

    Mixed first- and second-kind surface integral equations with (1/r) and {partial_derivative}/{partial_derivative} (1/r) kernels are generated by a variety of three-dimensional engineering problems. For such problems, Nystroem type algorithms can not be used directly, but an expansion for the unknown, rather than for the entire integrand, can be assumed and the product of the singular kernal and the unknown integrated analytically. Combining such an approach with a Galerkin or collocation scheme for computing the expansion coefficients is a general approach, but generates dense matrix problems. Recently developed fast algorithms for solving these dense matrix problems have been based on multipole-accelerated iterative methods, in which the fast multipole algorithm is used to rapidly compute the matrix-vector products in a Krylov-subspace based iterative method. Another approach to rapidly computing the dense matrix-vector products associated with discretized integral equations follows more along the lines of a multigrid algorithm, and involves projecting the surface unknowns onto a regular grid, then computing using the grid, and finally interpolating the results from the regular grid back to the surfaces. Here, the authors describe a precorrectted-FFT approach which can replace the fast multipole algorithm for accelerating the dense matrix-vector product associated with discretized potential integral equations. The precorrected-FFT method, described below, is an order n log(n) algorithm, and is asymptotically slower than the order n fast multipole algorithm. However, initial experimental results indicate the method may have a significant constant factor advantage for a variety of engineering problems.

  15. Satellite orbit determination by tracking data from ground station with statistical Kalman filter algorithm

    NASA Astrophysics Data System (ADS)

    Culp, Robert D.; Mackison, Don; Fu, Ho-Ling

    This paper deals with an advanced Kalman filter application to orbit determination from satellite tracking data. Modern control theory is used to set up an optimal Kalman gain for the estimation problem and to estimate its errors out of the system outputs. The classical orbit determination techniques have been used over the years for the evaluation of data analysis. A recent study was conducted to find the initial state values by modern orbit determination with Kalman gain. An original algorithm introduced by Born et al. (1986) has been applied to the spacecraft and earth satellite orbit determination for several years. The determination of the desired process and special Kalman gain for the best estimator include three kinds of computational algorithms: Batch, Sequential, and Extended Sequential processors. The model is based on a minimum variance using estimation and prediction techniques. Moreover, the estimation and computational algorithms have been modified in the UNIX system simulating to the TOPEX satellite orbit data process.

  16. Image Artifacts Resulting from Gamma-Ray Tracking Algorithms Used with Compton Imagers

    SciTech Connect

    Seifert, Carolyn E.; He, Zhong

    2005-10-01

    For Compton imaging it is necessary to determine the sequence of gamma-ray interactions in a single detector or array of detectors. This can be done by time-of-flight measurements if the interactions are sufficiently far apart. However, in small detectors the time between interactions can be too small to measure, and other means of gamma-ray sequencing must be used. In this work, several popular sequencing algorithms are reviewed for sequences with two observed events and three or more observed events in the detector. These algorithms can result in poor imaging resolution and introduce artifacts in the backprojection images. The effects of gamma-ray tracking algorithms on Compton imaging are explored in the context of the 4π Compton imager built by the University of Michigan.

  17. A Trend for Increased Risk of Revision Surgery due to Deep Infection following Fast-Track Hip Arthroplasty.

    PubMed

    Amlie, Einar; Lerdal, Anners; Gay, Caryl L; Høvik, Øystein; Nordsletten, Lars; Dimmen, Sigbjørn

    2016-01-01

    Rates of revision surgery due to deep infection following total hip arthroplasty (THA) increased at a Norwegian hospital following implementation of fast-track procedures. The purpose of this study was to determine whether selected demographic (age and sex) and clinical (body mass index, American Society of Anesthesiologists (ASA) classification, surgery duration, length of hospital stay, cemented versus uncemented prosthesis, and fast-track procedures) factors were associated with higher risk of revision surgery due to deep infection following THA. In a prospective designed study 4,406 patients undergoing primary THA between January 2001 and January 2013 where included. Rates of infection-related revision surgery within 3 months of THA were higher among males and among patients who received fast-track THA. Adjusting for sex and age, the implemented fast-track elements were significantly associated with increased risk of revision surgery. Risk of infection-related revision surgery was unrelated to body mass index, physical status, surgery duration, length of hospital stay, and prosthesis type. Because local infiltration analgesia, drain cessation, and early mobilization were introduced in combination, it could not be determined which component or combination of components imposed the increased risk. The findings in this small sample raise concern about fast-track THA but require replication in other samples. PMID:27034841

  18. A Trend for Increased Risk of Revision Surgery due to Deep Infection following Fast-Track Hip Arthroplasty

    PubMed Central

    Amlie, Einar; Lerdal, Anners; Gay, Caryl L.; Høvik, Øystein; Nordsletten, Lars; Dimmen, Sigbjørn

    2016-01-01

    Rates of revision surgery due to deep infection following total hip arthroplasty (THA) increased at a Norwegian hospital following implementation of fast-track procedures. The purpose of this study was to determine whether selected demographic (age and sex) and clinical (body mass index, American Society of Anesthesiologists (ASA) classification, surgery duration, length of hospital stay, cemented versus uncemented prosthesis, and fast-track procedures) factors were associated with higher risk of revision surgery due to deep infection following THA. In a prospective designed study 4,406 patients undergoing primary THA between January 2001 and January 2013 where included. Rates of infection-related revision surgery within 3 months of THA were higher among males and among patients who received fast-track THA. Adjusting for sex and age, the implemented fast-track elements were significantly associated with increased risk of revision surgery. Risk of infection-related revision surgery was unrelated to body mass index, physical status, surgery duration, length of hospital stay, and prosthesis type. Because local infiltration analgesia, drain cessation, and early mobilization were introduced in combination, it could not be determined which component or combination of components imposed the increased risk. The findings in this small sample raise concern about fast-track THA but require replication in other samples. PMID:27034841

  19. General Structure Design for Fast Image Processing Algorithms Based upon FPGA DSP Slice

    NASA Astrophysics Data System (ADS)

    Wasfy, Wael; Zheng, Hong

    Increasing the speed and accuracy for a fast image processing algorithms during computing the image intensity for low level 3x3 algorithms with different kernel but having the same parallel calculation method is our target to achieve in this paper. FPGA is one of the fastest embedded systems that can be used for implementing the fast image processing image algorithms by using DSP slice module inside the FPGA we aimed to get the advantage of the DSP slice as a faster, accurate, higher number of bits in calculations and different calculated equation maneuver capabilities. Using a higher number of bits during algorithm calculations will lead to a higher accuracy compared with using the same image algorithm calculations with less number of bits, also reducing FPGA resources as minimum as we can and according to algorithm calculations needs is a very important goal to achieve. So in the recommended design we used as minimum DSP slice as we can and as a benefit of using DSP slice is higher calculations accuracy as the DSP capabilities of having 48 bit accuracy in addition and 18 x 18 bit accuracy in multiplication. For proofing the design, Gaussian filter and Sobelx edge detector image processing algorithms have been chosen to be implemented. Also we made a comparison with another design for proofing the improvements of the accuracy and speed of calculations, the other design as will be mentioned later on this paper is using maximum 12 bit accuracy in adding or multiplying calculations.

  20. A Matrix Computation View of the FastMap and RobustMap Dimension Reduction Algorithms

    SciTech Connect

    Ostrouchov, George

    2009-01-01

    Given a set of pairwise object distances and a dimension $k$, FastMap and RobustMap algorithms compute a set of $k$-dimensional coordinates for the objects. These metric space embedding methods implicitly assume a higher-dimensional coordinate representation and are a sequence of translations and orthogonal projections based on a sequence of object pair selections (called pivot pairs). We develop a matrix computation viewpoint of these algorithms that operates on the coordinate representation explicitly using Householder reflections. The resulting Coordinate Mapping Algorithm (CMA) is a fast approximate alternative to truncated principal component analysis (PCA) and it brings the FastMap and RobustMap algorithms into the mainstream of numerical computation where standard BLAS building blocks are used. Motivated by the geometric nature of the embedding methods, we further show that truncated PCA can be computed with CMA by specific pivot pair selections. Describing FastMap, RobustMap, and PCA as CMA computations with different pivot pair choices unifies the methods along a pivot pair selection spectrum. We also sketch connections to the semi-discrete decomposition and the QLP decomposition.

  1. Preliminary versions of the MATLAB tensor classes for fast algorithm prototyping.

    SciTech Connect

    Bader, Brett William; Kolda, Tamara Gibson

    2004-07-01

    We present the source code for three MATLAB classes for manipulating tensors in order to allow fast algorithm prototyping. A tensor is a multidimensional or Nway array. This is a supplementary report; details on using this code are provided separately in SAND-XXXX.

  2. A fast D.F.T. algorithm using complex integer transforms

    NASA Technical Reports Server (NTRS)

    Reed, I. S.; Truong, T. K.

    1978-01-01

    Winograd (1976) has developed a new class of algorithms which depend heavily on the computation of a cyclic convolution for computing the conventional DFT (discrete Fourier transform); this new algorithm, for a few hundred transform points, requires substantially fewer multiplications than the conventional FFT algorithm. Reed and Truong have defined a special class of finite Fourier-like transforms over GF(q squared), where q = 2 to the p power minus 1 is a Mersenne prime for p = 2, 3, 5, 7, 13, 17, 19, 31, 61. In the present paper it is shown that Winograd's algorithm can be combined with the aforementioned Fourier-like transform to yield a new algorithm for computing the DFT. A fast method for accurately computing the DFT of a sequence of complex numbers of very long transform-lengths is thus obtained.

  3. A Fast Clustering Algorithm for Data with a Few Labeled Instances

    PubMed Central

    Yang, Jinfeng; Xiao, Yong; Wang, Jiabing; Ma, Qianli; Shen, Yanhua

    2015-01-01

    The diameter of a cluster is the maximum intracluster distance between pairs of instances within the same cluster, and the split of a cluster is the minimum distance between instances within the cluster and instances outside the cluster. Given a few labeled instances, this paper includes two aspects. First, we present a simple and fast clustering algorithm with the following property: if the ratio of the minimum split to the maximum diameter (RSD) of the optimal solution is greater than one, the algorithm returns optimal solutions for three clustering criteria. Second, we study the metric learning problem: learn a distance metric to make the RSD as large as possible. Compared with existing metric learning algorithms, one of our metric learning algorithms is computationally efficient: it is a linear programming model rather than a semidefinite programming model used by most of existing algorithms. We demonstrate empirically that the supervision and the learned metric can improve the clustering quality. PMID:25861252

  4. Study of absolute fast neutron dosimetry using CR-39 track detectors

    NASA Astrophysics Data System (ADS)

    El-Sersy, A. R.

    2010-06-01

    In this work, CR-39 track detectors have extensively been used in the determination of fast neutron fluence-to-dose factor. The registration efficiency, ɛ, of CR-39 detectors for fast neutrons was calculated using different theoretical approaches according to each mode of neutron interaction with the constituent atoms (H, C and O) of the detector material. The induced proton-recoiled showed the most common interaction among the others. The dependence of ɛ on both neutron energy and etching time was also studied. In addition, the neutron dose was calculated as a function of neutron energy in the range from 0.5 to 14 MeV using the values of (d E/d X) for each recoil particle in CR-39 detector. Results showed that the values of ɛ were obviously affected by both neutron energy and etching time where the contribution in ɛ from proton recoil was the most. The contribution from carbon and oxygen recoils in dose calculation was pronounced due to their higher corresponding values of d E/d X in comparison to those from proton recoils. The present calculated fluence-to-dose factor was in agreement with that either from ICRP no. 74 or from TRS no. 285 of IAEA, which reflected the importance of using CR-39 in absolute fast neutron dosimetry.

  5. Meanie3D - a mean-shift based, multivariate, multi-scale clustering and tracking algorithm

    NASA Astrophysics Data System (ADS)

    Simon, Jürgen-Lorenz; Malte, Diederich; Silke, Troemel

    2014-05-01

    Project OASE is the one of 5 work groups at the HErZ (Hans Ertel Centre for Weather Research), an ongoing effort by the German weather service (DWD) to further research at Universities concerning weather prediction. The goal of project OASE is to gain an object-based perspective on convective events by identifying them early in the onset of convective initiation and follow then through the entire lifecycle. The ability to follow objects in this fashion requires new ways of object definition and tracking, which incorporate all the available data sets of interest, such as Satellite imagery, weather Radar or lightning counts. The Meanie3D algorithm provides the necessary tool for this purpose. Core features of this new approach to clustering (object identification) and tracking are the ability to identify objects using the mean-shift algorithm applied to a multitude of variables (multivariate), as well as the ability to detect objects on various scales (multi-scale) using elements of Scale-Space theory. The algorithm works in 2D as well as 3D without modifications. It is an extension of a method well known from the field of computer vision and image processing, which has been tailored to serve the needs of the meteorological community. In spite of the special application to be demonstrated here (like convective initiation), the algorithm is easily tailored to provide clustering and tracking for a wide class of data sets and problems. In this talk, the demonstration is carried out on two of the OASE group's own composite sets. One is a 2D nationwide composite of Germany including C-Band Radar (2D) and Satellite information, the other a 3D local composite of the Bonn/Jülich area containing a high-resolution 3D X-Band Radar composite.

  6. a Fast and Robust Algorithm for Road Edges Extraction from LIDAR Data

    NASA Astrophysics Data System (ADS)

    Qiu, Kaijin; Sun, Kai; Ding, Kou; Shu, Zhen

    2016-06-01

    Fast mapping of roads plays an important role in many geospatial applications, such as infrastructure planning, traffic monitoring, and driver assistance. How to extract various road edges fast and robustly is a challenging task. In this paper, we present a fast and robust algorithm for the automatic road edges extraction from terrestrial mobile LiDAR data. The algorithm is based on a key observation: most roads around edges have difference in elevation and road edges with pavement are seen in two different planes. In our algorithm, we firstly extract a rough plane based on RANSAC algorithm, and then multiple refined planes which only contains pavement are extracted from the rough plane. The road edges are extracted based on these refined planes. In practice, there is a serious problem that the rough and refined planes usually extracted badly due to rough roads and different density of point cloud. To eliminate the influence of rough roads, the technology which is similar with the difference of DSM (digital surface model) and DTM (digital terrain model) is used, and we also propose a method which adjust the point clouds to a similar density to eliminate the influence of different density. Experiments show the validities of the proposed method with multiple datasets (e.g. urban road, highway, and some rural road). We use the same parameters through the experiments and our algorithm can achieve real-time processing speeds.

  7. "Mtrack 2.0": An ultra-scale tracking algorithm for low-resolution overhead imagery

    SciTech Connect

    Carrano, C J

    2008-09-26

    Overhead persistent surveillance systems are becoming more capable at acquiring wide-field image sequences for long time-spans. The need to exploit this data is becoming ever greater. The ability to track a single vehicle of interest or to track all the observable vehicles, which may number in the thousands, over large, cluttered regions while they persist in the imagery is very desirable. Typically, this imagery has many thousands of pixels on a side and is characterized by lower resolutions (e.g. {approx}0.5 meters/pixel to {approx}2.0 meters/pixel) and lower frame rates (e.g. {approx} sub-Hz to several Hz). We describe our ultra-scale capable implementation of a multiple-vehicle tracking algorithm for overhead persistent surveillance imagery. This work builds upon an earlier report, where now the algorithm has been modified for improved performance and has been substantially improved to handle much larger datasets in a much shorter time.

  8. Strain estimation by a Fourier Series-based extrema tracking algorithm for elastography.

    PubMed

    Wang, Wenxia; Hu, Danfeng; Wang, Jiajun; Zou, Wei

    2015-09-01

    In this paper, a new strain estimator using extrema tracking based on Fourier Series expansion (ETBFS) is proposed for ultrasonic elastography. In this method, the extremum is determined by solving an equation constructed by obtaining the first order derivative of the Fourier Series expansion and setting it to zero. Unlike other tracking algorithms, the ETBFS method can locate the extrema of radio frequency (RF) signals exactly between two adjacent sampling points and achieve a sub-sample accuracy without additional explicit interpolation. The correspondence between the located extrema in the pre- and post-compressed RF signal segments are constructed with a fine matching technique, with which the displacements and strains are estimated. Experimental results on a finite-element-modeling (FEM) simulation phantom show that the new proposed method can provide a more accurate displacement estimation than the standard cross-correlation (CC)-based method and the scale-invariant keypoints tracking (SIKT) algorithm. Moreover, performance analysis in terms of elastographic signal-to-noise ratio (SNRe), elastographic contrast-to-noise ratio (CNRe) and the real-versus-estimated strain error (RESE) also indicate that the dynamic range of the strain filter and its sensitivity can be improved with this new method. PMID:26096883

  9. Prediction of engine performance and wall erosion due to film cooling for the 'fast track' ablative thrust chamber

    NASA Technical Reports Server (NTRS)

    Trinh, Huu P.

    1994-01-01

    Efforts have been made at the Propulsion Laboratory (MSFC) to design and develop new liquid rocket engines for small-class launch vehicles. Emphasis of the efforts is to reduce the engine development time with the use of conventional designs while meeting engine reliability criteria. Consequently, the engine cost should be reduced. A demonstrative ablative thrust chamber, called 'fast-track', has been built. To support the design of the 'fast-track' thrust chamber, predictions of the wall temperature and ablation erosion rate of the 'fast-track' thrust chamber have been performed using the computational fluid dynamics program REFLEQS (Reactive Flow Equation Solver). The analysis is intended to assess the amount of fuel to be used for film cooling so that the erosion rate of the chamber ablation does not exceed its allowable limit. In addition, the thrust chamber performance loss due to an increase of the film cooling is examined.

  10. FastGGM: An Efficient Algorithm for the Inference of Gaussian Graphical Model in Biological Networks.

    PubMed

    Wang, Ting; Ren, Zhao; Ding, Ying; Fang, Zhou; Sun, Zhe; MacDonald, Matthew L; Sweet, Robert A; Wang, Jieru; Chen, Wei

    2016-02-01

    Biological networks provide additional information for the analysis of human diseases, beyond the traditional analysis that focuses on single variables. Gaussian graphical model (GGM), a probability model that characterizes the conditional dependence structure of a set of random variables by a graph, has wide applications in the analysis of biological networks, such as inferring interaction or comparing differential networks. However, existing approaches are either not statistically rigorous or are inefficient for high-dimensional data that include tens of thousands of variables for making inference. In this study, we propose an efficient algorithm to implement the estimation of GGM and obtain p-value and confidence interval for each edge in the graph, based on a recent proposal by Ren et al., 2015. Through simulation studies, we demonstrate that the algorithm is faster by several orders of magnitude than the current implemented algorithm for Ren et al. without losing any accuracy. Then, we apply our algorithm to two real data sets: transcriptomic data from a study of childhood asthma and proteomic data from a study of Alzheimer's disease. We estimate the global gene or protein interaction networks for the disease and healthy samples. The resulting networks reveal interesting interactions and the differential networks between cases and controls show functional relevance to the diseases. In conclusion, we provide a computationally fast algorithm to implement a statistically sound procedure for constructing Gaussian graphical model and making inference with high-dimensional biological data. The algorithm has been implemented in an R package named "FastGGM". PMID:26872036

  11. Comparison of Two Wire Chamber Track Reconstruction Algorithms Used in Hall A at Jefferson Lab

    SciTech Connect

    Dobbs, S.; Hansen, J.O.

    2003-01-01

    The Hall A collaboration at Jefferson Lab is currently in the process of redesigning and rewriting its physics analysis software in C++, using the ROOT libraries developed at CERN, to replace the Fortran-based ESPACE analyzer. In this paper, we carry out a detailed comparison of the wire chamber tracking results of both software packages. To this end, reconstruction of target quantities from detected tracks through the Vertical Drift Chambers (VDCs) in both spectrometer arms has been recently added to the C++ analyzer, to bring it to the same level as ESPACE. A study of the differences in the outputs of both analysis programs shows that while the output of the C++ analyzer is suitable for calibrations and studies that do not require high resolution, there are still many subtle differences that need to be resolved before it is ready for a productionquality release. The problems are most likely due to different cluster matching and track fitting algorithms used by both programs for tracks through the VDCs, as well as certain corrections missing from the C++ code. These problems and some possible solutions are discussed.

  12. Electric eels use high-voltage to track fast-moving prey

    PubMed Central

    Catania, Kenneth C.

    2015-01-01

    Electric eels (Electrophorus electricus) are legendary for their ability to incapacitate fish, humans, and horses with hundreds of volts of electricity. The function of this output as a weapon has been obvious for centuries but its potential role for electroreception has been overlooked. Here it is shown that electric eels use high-voltage simultaneously as a weapon and for precise and rapid electrolocation of fast-moving prey and conductors. Their speed, accuracy, and high-frequency pulse rate are reminiscent of bats using a ‘terminal feeding buzz' to track insects. Eel's exhibit ‘sensory conflict' when mechanosensory and electrosensory cues are separated, striking first toward mechanosensory cues and later toward conductors. Strikes initiated in the absence of conductors are aborted. In addition to providing new insights into the evolution of strongly electric fish and showing electric eels to be far more sophisticated than previously described, these findings reveal a trait with markedly dichotomous functions. PMID:26485580

  13. Tracking Down a Fast Instability in the PEP-II LER

    SciTech Connect

    Wienands, U.; Akre, R.; Curry, S.; DeBarger, S.; Decker, F.J.; Ecklund, S.; Fisher, A.S.; Heifets, S.A.; Krasnykh, A.; Kulikov, A.; Novokhatski, A.; Seeman, J.; Sullivan, M.K.; Teytelman, D.; Van Winkle, D.; Yocky, G.; /SLAC

    2007-05-18

    During Run 5, the beam in the PEP-II Low Energy Ring (LER) became affected by a predominantly vertical instability with very fast growth rate of 10...60/ms and varying threshold. The coherent amplitude of the oscillation was limited to approx. 1 mm peak and would damp down over a few tens of turns, however, beam loss set in even as the amplitude signal damped, causing a beam abort. This led to the conclusion that the bunches were actually blowing up. The appearance of a 2{nu}{sub S} line in the spectrum suggested a possible head-tail nature of the instability, although chromaticity was not effective in changing the threshold. The crucial hints in tracking down the cause turned out to be vacuum activity near the rf cavities and observance of signals on the cavity probes of certain rf cavities.

  14. Health Preemption Behind Closed Doors: Trade Agreements and Fast-Track Authority

    PubMed Central

    Crosbie, Eric; Gonzalez, Mariaelena

    2014-01-01

    Noncommunicable diseases result from consuming unhealthy products, including tobacco, which are promoted by transnational corporations. The tobacco industry uses preemption to block or reverse tobacco control policies. Preemption removes authority from jurisdictions where tobacco companies’ influence is weak and transfers it to jurisdictions where they have an advantage. International trade agreements relocate decisions about tobacco control policy to venues where there is little opportunity for public scrutiny, participation, and debate. Tobacco companies are using these agreements to preempt domestic authority over tobacco policy. Other transnational corporations that profit by promoting unhealthy foods could do the same. “Fast-track authority,” in which Congress cedes ongoing oversight authority to the President, further distances the public from the debate. With international agreements binding governments to prioritize trade over health, transparency and public oversight of the trade negotiation process is necessary to safeguard public health interests. PMID:25033124

  15. Fast cine-magnetic resonance imaging point tracking for prostate cancer radiation therapy planning

    NASA Astrophysics Data System (ADS)

    Dowling, J.; Dang, K.; Fox, Chris D.; Chandra, S.; Gill, Suki; Kron, T.; Pham, D.; Foroudi, F.

    2014-03-01

    The analysis of intra-fraction organ motion is important for improving the precision of radiation therapy treatment delivery. One method to quantify this motion is for one or more observers to manually identify anatomic points of interest (POIs) on each slice of a cine-MRI sequence. However this is labour intensive and inter- and intra- observer variation can introduce uncertainty. In this paper a fast method for non-rigid registration based point tracking in cine-MRI sagittal and coronal series is described which identifies POIs in 0.98 seconds per sagittal slice and 1.35 seconds per coronal slice. The manual and automatic points were highly correlated (r>0.99, p<0.001) for all organs and the difference generally less than 1mm. For prostate planning peristalsis and rectal gas can result in unpredictable out of plane motion, suggesting the results may require manual verification.

  16. The value of materials R&D in the fast track development of fusion power

    NASA Astrophysics Data System (ADS)

    Ward, D. J.; Taylor, N. P.; Cook, I.

    2007-08-01

    The objective of the international fusion program is the creation of power plants with attractive safety and environmental features and viable economics. There is a range of possible plants that can meet these objectives, as studied for instance in the recent EU studies of power plant concepts. All of the concepts satisfy safety and environmental objectives but the economic performance is interpreted differently in different world regions according to the perception of future energy markets. This leads to different materials performance targets and the direction and timescales of the materials development programme needed to meet those targets. In this paper, the implications for materials requirements of a fast track approach to fusion development are investigated. This includes a quantification of the overall benefits of more advanced materials: including the effect of trading off an extended development time against a reduced cost of electricity for resulting power plants.

  17. The effects of the fast track preventive intervention on the development of conduct disorder across childhood.

    PubMed

    2011-01-01

    The impact of the Fast Track intervention on externalizing disorders across childhood was examined. Eight hundred-ninety-one early-starting children (69% male; 51% African American) were randomly assigned by matched sets of schools to intervention or control conditions. The 10-year intervention addressed parent behavior-management, child social cognitive skills, reading, home visiting, mentoring, and classroom curricula. Outcomes included psychiatric diagnoses after grades 3, 6, 9, and 12 for conduct disorder, oppositional defiant disorder, attention deficit hyperactivity disorder, and any externalizing disorder. Significant interaction effects between intervention and initial risk level indicated that intervention prevented the lifetime prevalence of all diagnoses, but only among those at highest initial risk, suggesting that targeted intervention can prevent externalizing disorders to promote the raising of healthy children. PMID:21291445

  18. Health preemption behind closed doors: trade agreements and fast-track authority.

    PubMed

    Crosbie, Eric; Gonzalez, Mariaelena; Glantz, Stanton A

    2014-09-01

    Noncommunicable diseases result from consuming unhealthy products, including tobacco, which are promoted by transnational corporations. The tobacco industry uses preemption to block or reverse tobacco control policies. Preemption removes authority from jurisdictions where tobacco companies' influence is weak and transfers it to jurisdictions where they have an advantage. International trade agreements relocate decisions about tobacco control policy to venues where there is little opportunity for public scrutiny, participation, and debate. Tobacco companies are using these agreements to preempt domestic authority over tobacco policy. Other transnational corporations that profit by promoting unhealthy foods could do the same. "Fast-track authority," in which Congress cedes ongoing oversight authority to the President, further distances the public from the debate. With international agreements binding governments to prioritize trade over health, transparency and public oversight of the trade negotiation process is necessary to safeguard public health interests. PMID:25033124

  19. Electric eels use high-voltage to track fast-moving prey.

    PubMed

    Catania, Kenneth C

    2015-01-01

    Electric eels (Electrophorus electricus) are legendary for their ability to incapacitate fish, humans, and horses with hundreds of volts of electricity. The function of this output as a weapon has been obvious for centuries but its potential role for electroreception has been overlooked. Here it is shown that electric eels use high-voltage simultaneously as a weapon and for precise and rapid electrolocation of fast-moving prey and conductors. Their speed, accuracy, and high-frequency pulse rate are reminiscent of bats using a 'terminal feeding buzz' to track insects. Eel's exhibit 'sensory conflict' when mechanosensory and electrosensory cues are separated, striking first toward mechanosensory cues and later toward conductors. Strikes initiated in the absence of conductors are aborted. In addition to providing new insights into the evolution of strongly electric fish and showing electric eels to be far more sophisticated than previously described, these findings reveal a trait with markedly dichotomous functions. PMID:26485580

  20. Tracking Problem Solving by Multivariate Pattern Analysis and Hidden Markov Model Algorithms

    PubMed Central

    Anderson, John R.

    2011-01-01

    Multivariate pattern analysis can be combined with hidden Markov model algorithms to track the second-by-second thinking as people solve complex problems. Two applications of this methodology are illustrated with a data set taken from children as they interacted with an intelligent tutoring system for algebra. The first “mind reading” application involves using fMRI activity to track what students are doing as they solve a sequence of algebra problems. The methodology achieves considerable accuracy at determining both what problem-solving step the students are taking and whether they are performing that step correctly. The second “model discovery” application involves using statistical model evaluation to determine how many substates are involved in performing a step of algebraic problem solving. This research indicates that different steps involve different numbers of substates and these substates are associated with different fluency in algebra problem solving. PMID:21820455

  1. Accelerating D&D at Fernald: The fast track remediation design/bid package

    SciTech Connect

    Houser, S.M.; Albertin, M.F.; Borgman, T.D.; Zebick, W.A.

    1995-01-31

    The Fernald Environmental Management Project is a Department Of Energy (DOE) facility near Cincinnati, Ohio which provided high purity uranium metal products to support United States defense programs. Production operations were halted in 1989 to focus available resources on environmental restoration activities at the facility. Operable Unit 3 (OU3) is the designation given to the production area and production-associated facilities and equipment, including, but not limited to, all above and below ground structures, equipment, and utilities. In late spring of 1994, two decisions were made that established the long range strategy on how remedial designs (RD) and the bidding of remedial actions (RA) are approached for the decontamination and decommissioning (D&D) of the Fernald facilities. The first was to fast track the remediation design and bidding process for the first three D&D packages; and the second was to use standard performance specifications to streamline the decontamination and decommissioning process. This paper describes these strategies, identifies the key elements involved, and discusses the lessons learned that were associated with the approaches. A brief synopsis of these elements follows: (1) A facility complex grouping facilities into blocks of work was used for bid packages. (2) A task force approach involving required functional organizations was used to fast track the design and bidding process. (3) Standard Performance Specifications have been developed for each task to establish minimum acceptable criteria and provide the subcontractor flexibility. This approach also dramatically decreases costs for future D&D packages. (4) A key feature of value engineering has been the use of construction methods and techniques to drive the D&D cost significantly lower. (5) The bid package was structured around a modified IFB approach. This provides the successful bidder the opportunity to incorporate innovative ideas within the performance.

  2. FctClus: A Fast Clustering Algorithm for Heterogeneous Information Networks.

    PubMed

    Yang, Jing; Chen, Limin; Zhang, Jianpei

    2015-01-01

    It is important to cluster heterogeneous information networks. A fast clustering algorithm based on an approximate commute time embedding for heterogeneous information networks with a star network schema is proposed in this paper by utilizing the sparsity of heterogeneous information networks. First, a heterogeneous information network is transformed into multiple compatible bipartite graphs from the compatible point of view. Second, the approximate commute time embedding of each bipartite graph is computed using random mapping and a linear time solver. All of the indicator subsets in each embedding simultaneously determine the target dataset. Finally, a general model is formulated by these indicator subsets, and a fast algorithm is derived by simultaneously clustering all of the indicator subsets using the sum of the weighted distances for all indicators for an identical target object. The proposed fast algorithm, FctClus, is shown to be efficient and generalizable and exhibits high clustering accuracy and fast computation speed based on a theoretic analysis and experimental verification. PMID:26090857

  3. Detection and tracking of a moving target using SAR images with the particle filter-based track-before-detect algorithm.

    PubMed

    Gao, Han; Li, Jingwen

    2014-01-01

    A novel approach to detecting and tracking a moving target using synthetic aperture radar (SAR) images is proposed in this paper. Achieved with the particle filter (PF) based track-before-detect (TBD) algorithm, the approach is capable of detecting and tracking the low signal-to-noise ratio (SNR) moving target with SAR systems, which the traditional track-after-detect (TAD) approach is inadequate for. By incorporating the signal model of the SAR moving target into the algorithm, the ambiguity in target azimuth position and radial velocity is resolved while tracking, which leads directly to the true estimation. With the sub-area substituted for the whole area to calculate the likelihood ratio and a pertinent choice of the number of particles, the computational efficiency is improved with little loss in the detection and tracking performance. The feasibility of the approach is validated and the performance is evaluated with Monte Carlo trials. It is demonstrated that the proposed approach is capable to detect and track a moving target with SNR as low as 7 dB, and outperforms the traditional TAD approach when the SNR is below 14 dB. PMID:24949640

  4. Detection and Tracking of a Moving Target Using SAR Images with the Particle Filter-Based Track-Before-Detect Algorithm

    PubMed Central

    Gao, Han; Li, Jingwen

    2014-01-01

    A novel approach to detecting and tracking a moving target using synthetic aperture radar (SAR) images is proposed in this paper. Achieved with the particle filter (PF) based track-before-detect (TBD) algorithm, the approach is capable of detecting and tracking the low signal-to-noise ratio (SNR) moving target with SAR systems, which the traditional track-after-detect (TAD) approach is inadequate for. By incorporating the signal model of the SAR moving target into the algorithm, the ambiguity in target azimuth position and radial velocity is resolved while tracking, which leads directly to the true estimation. With the sub-area substituted for the whole area to calculate the likelihood ratio and a pertinent choice of the number of particles, the computational efficiency is improved with little loss in the detection and tracking performance. The feasibility of the approach is validated and the performance is evaluated with Monte Carlo trials. It is demonstrated that the proposed approach is capable to detect and track a moving target with SNR as low as 7 dB, and outperforms the traditional TAD approach when the SNR is below 14 dB. PMID:24949640

  5. Fast phase-added stereogram algorithm for generation of photorealistic 3D content.

    PubMed

    Kang, Hoonjong; Stoykova, Elena; Yoshikawa, Hiroshi

    2016-01-20

    A new phase-added stereogram algorithm for accelerated computation of holograms from a point cloud model is proposed. The algorithm relies on the hologram segmentation, sampling of directional information, and usage of the fast Fourier transform with a finer grid in the spatial frequency domain than is provided by the segment size. The algorithm gives improved quality of reconstruction due to new phase compensation introduced in the segment fringe patterns. The result is finer beam steering leading to high peak intensity and a large peak signal-to-noise ratio in reconstruction. The feasibility of the algorithm is checked by the generation of 3D contents for a color wavefront printer. PMID:26835945

  6. Maneuvering target tracking algorithm based on current statistical model in three dimensional space

    NASA Astrophysics Data System (ADS)

    Huang, Ligang; Yan, Kang; Wang, Xiangdong

    2015-07-01

    This paper is mainly to solve the problems associated with maneuvering target tracking based current statistical model in three dimensional space. Firstly, a three-dimensional model of the nine state variables is presented. Then adaptive Kalman filtering algorithm is designed with the motor acceleration data mean and variance. Finally, A simulation about the adaptive Kalman filtering put forward by this thesis and the direct calculation method is given, which aim at the maneuvering target in three-dimension. The results show the good performances such as better target position, velocity and acceleration estimates brought by the proposed approach by presenting and discussing the simulation results.

  7. Optical bullet-tracking algorithms for weapon localization in urban environments

    SciTech Connect

    Roberts, R S; Breitfeller, E F

    2006-03-31

    Localization of the sources of small-arms fire, mortars, and rocket propelled grenades is an important problem in urban combat. Weapons of this type produce characteristic signatures, such as muzzle flashes, that are visible in the infrared. Indeed, several systems have been developed that exploit the infrared signature of muzzle flash to locate the positions of shooters. However, systems based on muzzle flash alone can have difficulty localizing weapons if the muzzle flash is obscured or suppressed. Moreover, optical clutter can be problematic to systems that rely on muzzle flash alone. Lawrence Livermore National Laboratory (LLNL) has developed a projectile tracking system that detects and localizes sources of small-arms fire, mortars and similar weapons using the thermal signature of the projectile rather than a muzzle flash. The thermal signature of a projectile, caused by friction as the projectile travels along its trajectory, cannot be concealed and is easily discriminated from optical clutter. The LLNL system was recently demonstrated at the MOUT facility of the Aberdeen Test Center [1]. In the live-fire demonstration, shooters armed with a variety of small-arms, including M-16s, AK-47s, handguns, mortars and rockets, were arranged at several positions in around the facility. Experiments ranged from a single-weapon firing a single-shot to simultaneous fire of all weapons on full automatic. The LLNL projectile tracking system was demonstrated to localize multiple shooters at ranges up to 400m, far greater than previous demonstrations. Furthermore, the system was shown to be immune to optical clutter that is typical in urban combat. This paper describes the image processing and localization algorithms designed to exploit the thermal signature of projectiles for shooter localization. The paper begins with a description of the image processing that extracts projectile information from a sequence of infrared images. Key to the processing is an adaptive spatio

  8. A fast-initializing digital equalizer with on-line tracking for data communications

    NASA Technical Reports Server (NTRS)

    Houts, R. C.; Barksdale, W. J.

    1974-01-01

    A theory is developed for a digital equalizer for use in reducing intersymbol interference (ISI) on high speed data communications channels. The equalizer is initialized with a single isolated transmitter pulse, provided the signal-to-noise ratio (SNR) is not unusually low, then switches to a decision directed, on-line mode of operation that allows tracking of channel variations. Conditions for optimal tap-gain settings are obtained first for a transversal equalizer structure by using a mean squared error (MSE) criterion, a first order gradient algorithm to determine the adjustable equalizer tap-gains, and a sequence of isolated initializing pulses. Since the rate of tap-gain convergence depends on the eigenvalues of a channel output correlation matrix, convergence can be improved by making a linear transformation on to obtain a new correlation matrix.

  9. Tracking Microstructure of Crystalline Materials: A Post-Processing Algorithm for Atomistic Simulations

    NASA Astrophysics Data System (ADS)

    Panzarino, Jason F.; Rupert, Timothy J.

    2014-03-01

    Atomistic simulations have become a powerful tool in materials research due to the extremely fine spatial and temporal resolution provided by such techniques. To understand the fundamental principles that govern material behavior at the atomic scale and directly connect to experimental works, it is necessary to quantify the microstructure of materials simulated with atomistics. Specifically, quantitative tools for identifying crystallites, their crystallographic orientation, and overall sample texture do not currently exist. Here, we develop a post-processing algorithm capable of characterizing such features, while also documenting their evolution during a simulation. In addition, the data is presented in a way that parallels the visualization methods used in traditional experimental techniques. The utility of this algorithm is illustrated by analyzing several types of simulation cells that are commonly found in the atomistic modeling literature but could also be applied to a variety of other atomistic studies that require precise identification and tracking of microstructure.

  10. Experimental investigation of a moving averaging algorithm for motion perpendicular to the leaf travel direction in dynamic MLC target tracking

    PubMed Central

    Yoon, Jai-Woong; Sawant, Amit; Suh, Yelin; Cho, Byung-Chul; Suh, Tae-Suk; Keall, Paul

    2011-01-01

    Purpose: In dynamic multileaf collimator (MLC) motion tracking with complex intensity-modulated radiation therapy (IMRT) fields, target motion perpendicular to the MLC leaf travel direction can cause beam holds, which increase beam delivery time by up to a factor of 4. As a means to balance delivery efficiency and accuracy, a moving average algorithm was incorporated into a dynamic MLC motion tracking system (i.e., moving average tracking) to account for target motion perpendicular to the MLC leaf travel direction. The experimental investigation of the moving average algorithm compared with real-time tracking and no compensation beam delivery is described.Methods: The properties of the moving average algorithm were measured and compared with those of real-time tracking (dynamic MLC motion tracking accounting for both target motion parallel and perpendicular to the leaf travel direction) and no compensation beam delivery. The algorithm was investigated using a synthetic motion trace with a baseline drift and four patient-measured 3D tumor motion traces representing regular and irregular motions with varying baseline drifts. Each motion trace was reproduced by a moving platform. The delivery efficiency, geometric accuracy, and dosimetric accuracy were evaluated for conformal, step-and-shoot IMRT, and dynamic sliding window IMRT treatment plans using the synthetic and patient motion traces. The dosimetric accuracy was quantified via a γ-test with a 3%/3 mm criterion.Results: The delivery efficiency ranged from 89 to 100% for moving average tracking, 26%–100% for real-time tracking, and 100% (by definition) for no compensation. The root-mean-square geometric error ranged from 3.2 to 4.0 mm for moving average tracking, 0.7–1.1 mm for real-time tracking, and 3.7–7.2 mm for no compensation. The percentage of dosimetric points failing the γ-test ranged from 4 to 30% for moving average tracking, 0%–23% for real-time tracking, and 10%–47% for no compensation

  11. Experimental investigation of a moving averaging algorithm for motion perpendicular to the leaf travel direction in dynamic MLC target tracking

    SciTech Connect

    Yoon, Jai-Woong; Sawant, Amit; Suh, Yelin; Cho, Byung-Chul; Suh, Tae-Suk; Keall, Paul

    2011-07-15

    Purpose: In dynamic multileaf collimator (MLC) motion tracking with complex intensity-modulated radiation therapy (IMRT) fields, target motion perpendicular to the MLC leaf travel direction can cause beam holds, which increase beam delivery time by up to a factor of 4. As a means to balance delivery efficiency and accuracy, a moving average algorithm was incorporated into a dynamic MLC motion tracking system (i.e., moving average tracking) to account for target motion perpendicular to the MLC leaf travel direction. The experimental investigation of the moving average algorithm compared with real-time tracking and no compensation beam delivery is described. Methods: The properties of the moving average algorithm were measured and compared with those of real-time tracking (dynamic MLC motion tracking accounting for both target motion parallel and perpendicular to the leaf travel direction) and no compensation beam delivery. The algorithm was investigated using a synthetic motion trace with a baseline drift and four patient-measured 3D tumor motion traces representing regular and irregular motions with varying baseline drifts. Each motion trace was reproduced by a moving platform. The delivery efficiency, geometric accuracy, and dosimetric accuracy were evaluated for conformal, step-and-shoot IMRT, and dynamic sliding window IMRT treatment plans using the synthetic and patient motion traces. The dosimetric accuracy was quantified via a {gamma}-test with a 3%/3 mm criterion. Results: The delivery efficiency ranged from 89 to 100% for moving average tracking, 26%-100% for real-time tracking, and 100% (by definition) for no compensation. The root-mean-square geometric error ranged from 3.2 to 4.0 mm for moving average tracking, 0.7-1.1 mm for real-time tracking, and 3.7-7.2 mm for no compensation. The percentage of dosimetric points failing the {gamma}-test ranged from 4 to 30% for moving average tracking, 0%-23% for real-time tracking, and 10%-47% for no compensation

  12. Track-Before-Detect Algorithm for Faint Moving Objects based on Random Sampling and Consensus

    NASA Astrophysics Data System (ADS)

    Dao, P.; Rast, R.; Schlaegel, W.; Schmidt, V.; Dentamaro, A.

    2014-09-01

    There are many algorithms developed for tracking and detecting faint moving objects in congested backgrounds. One obvious application is detection of targets in images where each pixel corresponds to the received power in a particular location. In our application, a visible imager operated in stare mode observes geostationary objects as fixed, stars as moving and non-geostationary objects as drifting in the field of view. We would like to achieve high sensitivity detection of the drifters. The ability to improve SNR with track-before-detect (TBD) processing, where target information is collected and collated before the detection decision is made, allows respectable performance against dim moving objects. Generally, a TBD algorithm consists of a pre-processing stage that highlights potential targets and a temporal filtering stage. However, the algorithms that have been successfully demonstrated, e.g. Viterbi-based and Bayesian-based, demand formidable processing power and memory. We propose an algorithm that exploits the quasi constant velocity of objects, the predictability of the stellar clutter and the intrinsically low false alarm rate of detecting signature candidates in 3-D, based on an iterative method called "RANdom SAmple Consensus” and one that can run real-time on a typical PC. The technique is tailored for searching objects with small telescopes in stare mode. Our RANSAC-MT (Moving Target) algorithm estimates parameters of a mathematical model (e.g., linear motion) from a set of observed data which contains a significant number of outliers while identifying inliers. In the pre-processing phase, candidate blobs were selected based on morphology and an intensity threshold that would normally generate unacceptable level of false alarms. The RANSAC sampling rejects candidates that conform to the predictable motion of the stars. Data collected with a 17 inch telescope by AFRL/RH and a COTS lens/EM-CCD sensor by the AFRL/RD Satellite Assessment Center is

  13. A fast and high performance multiple data integration algorithm for identifying human disease genes

    PubMed Central

    2015-01-01

    Background Integrating multiple data sources is indispensable in improving disease gene identification. It is not only due to the fact that disease genes associated with similar genetic diseases tend to lie close with each other in various biological networks, but also due to the fact that gene-disease associations are complex. Although various algorithms have been proposed to identify disease genes, their prediction performances and the computational time still should be further improved. Results In this study, we propose a fast and high performance multiple data integration algorithm for identifying human disease genes. A posterior probability of each candidate gene associated with individual diseases is calculated by using a Bayesian analysis method and a binary logistic regression model. Two prior probability estimation strategies and two feature vector construction methods are developed to test the performance of the proposed algorithm. Conclusions The proposed algorithm is not only generated predictions with high AUC scores, but also runs very fast. When only a single PPI network is employed, the AUC score is 0.769 by using F2 as feature vectors. The average running time for each leave-one-out experiment is only around 1.5 seconds. When three biological networks are integrated, the AUC score using F3 as feature vectors increases to 0.830, and the average running time for each leave-one-out experiment takes only about 12.54 seconds. It is better than many existing algorithms. PMID:26399620

  14. Temporal Gillespie Algorithm: Fast Simulation of Contagion Processes on Time-Varying Networks

    PubMed Central

    Vestergaard, Christian L.; Génois, Mathieu

    2015-01-01

    Stochastic simulations are one of the cornerstones of the analysis of dynamical processes on complex networks, and are often the only accessible way to explore their behavior. The development of fast algorithms is paramount to allow large-scale simulations. The Gillespie algorithm can be used for fast simulation of stochastic processes, and variants of it have been applied to simulate dynamical processes on static networks. However, its adaptation to temporal networks remains non-trivial. We here present a temporal Gillespie algorithm that solves this problem. Our method is applicable to general Poisson (constant-rate) processes on temporal networks, stochastically exact, and up to multiple orders of magnitude faster than traditional simulation schemes based on rejection sampling. We also show how it can be extended to simulate non-Markovian processes. The algorithm is easily applicable in practice, and as an illustration we detail how to simulate both Poissonian and non-Markovian models of epidemic spreading. Namely, we provide pseudocode and its implementation in C++ for simulating the paradigmatic Susceptible-Infected-Susceptible and Susceptible-Infected-Recovered models and a Susceptible-Infected-Recovered model with non-constant recovery rates. For empirical networks, the temporal Gillespie algorithm is here typically from 10 to 100 times faster than rejection sampling. PMID:26517860

  15. The fast simulated annealing algorithm applied to the search problem in LEED

    NASA Astrophysics Data System (ADS)

    Nascimento, V. B.; de Carvalho, V. E.; de Castilho, C. M. C.; Costa, B. V.; Soares, E. A.

    2001-07-01

    In this work we present new results obtained from the application of the fast simulated algorithm (FSA) to the surface structure determination of the Ag(1 1 0) and CdTe(1 1 0) systems. The influence of a control parameter, the "initial temperature", on the FSA search process was investigated. A scaling behaviour, that measures the efficiency of a search method as a function of the number of parameters to be varied, was obtained for the FSA algorithm, and indicated a favourable linear scaling ( N1).

  16. A fast optimization algorithm for multicriteria intensity modulated proton therapy planning

    SciTech Connect

    Chen Wei; Craft, David; Madden, Thomas M.; Zhang, Kewu; Kooy, Hanne M.; Herman, Gabor T.

    2010-09-15

    Purpose: To describe a fast projection algorithm for optimizing intensity modulated proton therapy (IMPT) plans and to describe and demonstrate the use of this algorithm in multicriteria IMPT planning. Methods: The authors develop a projection-based solver for a class of convex optimization problems and apply it to IMPT treatment planning. The speed of the solver permits its use in multicriteria optimization, where several optimizations are performed which span the space of possible treatment plans. The authors describe a plan database generation procedure which is customized to the requirements of the solver. The optimality precision of the solver can be specified by the user. Results: The authors apply the algorithm to three clinical cases: A pancreas case, an esophagus case, and a tumor along the rib cage case. Detailed analysis of the pancreas case shows that the algorithm is orders of magnitude faster than industry-standard general purpose algorithms (MOSEK's interior point optimizer, primal simplex optimizer, and dual simplex optimizer). Additionally, the projection solver has almost no memory overhead. Conclusions: The speed and guaranteed accuracy of the algorithm make it suitable for use in multicriteria treatment planning, which requires the computation of several diverse treatment plans. Additionally, given the low memory overhead of the algorithm, the method can be extended to include multiple geometric instances and proton range possibilities, for robust optimization.

  17. A fast optimization algorithm for multicriteria intensity modulated proton therapy planning

    PubMed Central

    Chen, Wei; Craft, David; Madden, Thomas M.; Zhang, Kewu; Kooy, Hanne M.; Herman, Gabor T.

    2010-01-01

    Purpose: To describe a fast projection algorithm for optimizing intensity modulated proton therapy (IMPT) plans and to describe and demonstrate the use of this algorithm in multicriteria IMPT planning. Methods: The authors develop a projection-based solver for a class of convex optimization problems and apply it to IMPT treatment planning. The speed of the solver permits its use in multicriteria optimization, where several optimizations are performed which span the space of possible treatment plans. The authors describe a plan database generation procedure which is customized to the requirements of the solver. The optimality precision of the solver can be specified by the user. Results: The authors apply the algorithm to three clinical cases: A pancreas case, an esophagus case, and a tumor along the rib cage case. Detailed analysis of the pancreas case shows that the algorithm is orders of magnitude faster than industry-standard general purpose algorithms (MOSEK’s interior point optimizer, primal simplex optimizer, and dual simplex optimizer). Additionally, the projection solver has almost no memory overhead. Conclusions: The speed and guaranteed accuracy of the algorithm make it suitable for use in multicriteria treatment planning, which requires the computation of several diverse treatment plans. Additionally, given the low memory overhead of the algorithm, the method can be extended to include multiple geometric instances and proton range possibilities, for robust optimization. PMID:20964213

  18. Burst suppression probability algorithms: state-space methods for tracking EEG burst suppression

    NASA Astrophysics Data System (ADS)

    Chemali, Jessica; Ching, ShiNung; Purdon, Patrick L.; Solt, Ken; Brown, Emery N.

    2013-10-01

    Objective. Burst suppression is an electroencephalogram pattern in which bursts of electrical activity alternate with an isoelectric state. This pattern is commonly seen in states of severely reduced brain activity such as profound general anesthesia, anoxic brain injuries, hypothermia and certain developmental disorders. Devising accurate, reliable ways to quantify burst suppression is an important clinical and research problem. Although thresholding and segmentation algorithms readily identify burst suppression periods, analysis algorithms require long intervals of data to characterize burst suppression at a given time and provide no framework for statistical inference. Approach. We introduce the concept of the burst suppression probability (BSP) to define the brain's instantaneous propensity of being in the suppressed state. To conduct dynamic analyses of burst suppression we propose a state-space model in which the observation process is a binomial model and the state equation is a Gaussian random walk. We estimate the model using an approximate expectation maximization algorithm and illustrate its application in the analysis of rodent burst suppression recordings under general anesthesia and a patient during induction of controlled hypothermia. Main result. The BSP algorithms track burst suppression on a second-to-second time scale, and make possible formal statistical comparisons of burst suppression at different times. Significance. The state-space approach suggests a principled and informative way to analyze burst suppression that can be used to monitor, and eventually to control, the brain states of patients in the operating room and in the intensive care unit.

  19. A Region Tracking-Based Vehicle Detection Algorithm in Nighttime Traffic Scenes

    PubMed Central

    Wang, Jianqiang; Sun, Xiaoyan; Guo, Junbin

    2013-01-01

    The preceding vehicles detection technique in nighttime traffic scenes is an important part of the advanced driver assistance system (ADAS). This paper proposes a region tracking-based vehicle detection algorithm via the image processing technique. First, the brightness of the taillights during nighttime is used as the typical feature, and we use the existing global detection algorithm to detect and pair the taillights. When the vehicle is detected, a time series analysis model is introduced to predict vehicle positions and the possible region (PR) of the vehicle in the next frame. Then, the vehicle is only detected in the PR. This could reduce the detection time and avoid the false pairing between the bright spots in the PR and the bright spots out of the PR. Additionally, we present a thresholds updating method to make the thresholds adaptive. Finally, experimental studies are provided to demonstrate the application and substantiate the superiority of the proposed algorithm. The results show that the proposed algorithm can simultaneously reduce both the false negative detection rate and the false positive detection rate.

  20. SMG: Fast scalable greedy algorithm for influence maximization in social networks

    NASA Astrophysics Data System (ADS)

    Heidari, Mehdi; Asadpour, Masoud; Faili, Hesham

    2015-02-01

    Influence maximization is the problem of finding k most influential nodes in a social network. Many works have been done in two different categories, greedy approaches and heuristic approaches. The greedy approaches have better influence spread, but lower scalability on large networks. The heuristic approaches are scalable and fast but not for all type of networks. Improving the scalability of greedy approach is still an open and hot issue. In this work we present a fast greedy algorithm called State Machine Greedy that improves the existing algorithms by reducing calculations in two parts: (1) counting the traversing nodes in estimate propagation procedure, (2) Monte-Carlo graph construction in simulation of diffusion. The results show that our method makes a huge improvement in the speed over the existing greedy approaches.

  1. Study of cluster reconstruction and track fitting algorithms for CGEM-IT at BESIII

    NASA Astrophysics Data System (ADS)

    Guo, Yue; Wang, Liang-Liang; Ju, Xu-Dong; Wu, Ling-Hui; Xiu, Qing-Lei; Wang, Hai-Xia; Dong, Ming-Yi; Hu, Jing-Ran; Li, Wei-Dong; Li, Wei-Guo; Liu, Huai-Min; Qun, Ou-Yang; Shen, Xiao-Yan; Yuan, Ye; Zhang, Yao

    2016-01-01

    Considering the effects of aging on the existing Inner Drift Chamber (IDC) of BESIII, a GEM-based inner tracker, the Cylindrical-GEM Inner Tracker (CGEM-IT), is proposed to be designed and constructed as an upgrade candidate for the IDC. This paper introduces a full simulation package for the CGEM-IT with a simplified digitization model, and describes the development of software for cluster reconstruction and track fitting, using a track fitting algorithm based on the Kalman filter method. Preliminary results for the reconstruction algorithms which are obtained using a Monte Carlo sample of single muon events in the CGEM-IT, show that the CGEM-IT has comparable momentum resolution and transverse vertex resolution to the IDC, and a better z-direction resolution than the IDC. Supported by National Key Basic Research Program of China (2015CB856700), National Natural Science Foundation of China (11205184, 11205182) and Joint Funds of National Natural Science Foundation of China (U1232201)

  2. 42 CFR 422.626 - Fast-track appeals of service terminations to independent review entities (IREs).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 3 2014-10-01 2014-10-01 false Fast-track appeals of service terminations to independent review entities (IREs). 422.626 Section 422.626 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM (CONTINUED)...

  3. 42 CFR 422.626 - Fast-track appeals of service terminations to independent review entities (IREs).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false Fast-track appeals of service terminations to independent review entities (IREs). 422.626 Section 422.626 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM MEDICARE ADVANTAGE...

  4. 42 CFR 422.626 - Fast-track appeals of service terminations to independent review entities (IREs).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 3 2012-10-01 2012-10-01 false Fast-track appeals of service terminations to independent review entities (IREs). 422.626 Section 422.626 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM (CONTINUED)...

  5. 42 CFR 422.626 - Fast-track appeals of service terminations to independent review entities (IREs).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 3 2011-10-01 2011-10-01 false Fast-track appeals of service terminations to independent review entities (IREs). 422.626 Section 422.626 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM MEDICARE ADVANTAGE...

  6. 42 CFR 422.626 - Fast-track appeals of service terminations to independent review entities (IREs).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 3 2013-10-01 2013-10-01 false Fast-track appeals of service terminations to independent review entities (IREs). 422.626 Section 422.626 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM (CONTINUED)...

  7. The Politics of Global Education Policy: The Formation of the Education for All--Fast Track Initiative (FTI)

    ERIC Educational Resources Information Center

    Bermingham, Desmond

    2011-01-01

    This paper considers the macro and micro-political forces that influenced the development of the Education for All--Fast Track Initiative in its formative years from 2002-2009. The author uses the conceptual framework of the network organisation to analyse the complex interaction of personal, political and institutional forces that shaped the FTI…

  8. Catalyzing Country Ownership and Aid Effectiveness: Role of the Education for All-Fast Track Initiative Catalytic Fund

    ERIC Educational Resources Information Center

    Bashir, Sajitha

    2009-01-01

    This article examines the contribution of the Education for All-Fast Track Initiative (EFA-FTI) global partnership in strengthening aid effectiveness in the education sector, and specifically how the implementation modalities of the EFA-FTI Catalytic Fund (CF) have contributed to this strengthening. The empirical findings are based on a review…

  9. A comparative study of automatic image segmentation algorithms for target tracking in MR-IGRT.

    PubMed

    Feng, Yuan; Kawrakow, Iwan; Olsen, Jeff; Parikh, Parag J; Noel, Camille; Wooten, Omar; Du, Dongsu; Mutic, Sasa; Hu, Yanle

    2016-01-01

    On-board magnetic resonance (MR) image guidance during radiation therapy offers the potential for more accurate treatment delivery. To utilize the real-time image information, a crucial prerequisite is the ability to successfully segment and track regions of interest (ROI). The purpose of this work is to evaluate the performance of different segmentation algorithms using motion images (4 frames per second) acquired using a MR image-guided radiotherapy (MR-IGRT) system. Manual con-tours of the kidney, bladder, duodenum, and a liver tumor by an experienced radiation oncologist were used as the ground truth for performance evaluation. Besides the manual segmentation, images were automatically segmented using thresholding, fuzzy k-means (FKM), k-harmonic means (KHM), and reaction-diffusion level set evolution (RD-LSE) algorithms, as well as the tissue tracking algorithm provided by the ViewRay treatment planning and delivery system (VR-TPDS). The performance of the five algorithms was evaluated quantitatively by comparing with the manual segmentation using the Dice coefficient and target registration error (TRE) measured as the distance between the centroid of the manual ROI and the centroid of the automatically segmented ROI. All methods were able to successfully segment the bladder and the kidney, but only FKM, KHM, and VR-TPDS were able to segment the liver tumor and the duodenum. The performance of the thresholding, FKM, KHM, and RD-LSE algorithms degraded as the local image contrast decreased, whereas the performance of the VP-TPDS method was nearly independent of local image contrast due to the reference registration algorithm. For segmenting high-contrast images (i.e., kidney), the thresholding method provided the best speed (< 1 ms) with a satisfying accuracy (Dice = 0.95). When the image contrast was low, the VR-TPDS method had the best automatic contour. Results suggest an image quality determination procedure before segmentation and a combination of

  10. Mechanics of swimming of multi-body bacterial swarmers using non-labeled cell tracking algorithm

    NASA Astrophysics Data System (ADS)

    Phuyal, Kiran; Kim, Min Jun

    2013-01-01

    To better understand the survival strategy of bacterial swarmers and the mechanical advantages offered by the linear chain (head-tail) attachment of the multiple bacterial bodies in an individual swarmer cell at low Reynolds number, a non-labeled cell tracking algorithm was used to quantify the mechanics of multi-body flagellated bacteria, Serratia marcescens, swimming in a motility buffer that originally exhibited the swarming motility. Swarming is a type of bacterial motility that is characterized by the collective coordinated motion of differentiated swarmer cells on a two-dimensional surface such as agar. In this study, the bacterial swarmers with multiple cell bodies (2, 3, and 4) were extracted from the swarm plate, and then tracked individually after resuspending in the motility medium. Their motion was investigated and compared with individual undifferentiated swimming bacterial cells. The swarmers when released into the motility buffer swam actively without tumbles. Their speeds, orientations, and the diffusive properties were studied by tracking the individual cell trajectories over a short distance in two-dimensional field when the cells are swimming at a constant depth in a bulk aqueous environment. At short time scales, the ballistic trajectory was dominant for both multi-body swarmers and undifferentiated cells.

  11. Software-based Diffusion MR Human Brain Phantom for Evaluating Fiber-tracking Algorithms.

    PubMed

    Shi, Yundi; Roger, Gwendoline; Vachet, Clement; Budin, Francois; Maltbie, Eric; Verde, Audrey; Hoogstoel, Marion; Berger, Jean-Baptiste; Styner, Martin

    2013-03-13

    Fiber tracking provides insights into the brain white matter network and has become more and more popular in diffusion MR imaging. Hardware or software phantom provides an essential platform to investigate, validate and compare various tractography algorithms towards a "gold standard". Software phantoms excel due to their flexibility in varying imaging parameters, such as tissue composition, SNR, as well as potential to model various anatomies and pathologies. This paper describes a novel method in generating diffusion MR images with various imaging parameters from realistically appearing, individually varying brain anatomy based on predefined fiber tracts within a high-resolution human brain atlas. Specifically, joint, high resolution DWI and structural MRI brain atlases were constructed with images acquired from 6 healthy subjects (age 22-26) for the DWI data and 56 healthy subject (age 18-59) for the structural MRI data. Full brain fiber tracking was performed with filtered, two-tensor tractography in atlas space. A deformation field based principal component model from the structural MRI as well as unbiased atlas building was then employed to generate synthetic structural brain MR images that are individually varying. Atlas fiber tracts were accordingly warped into each synthetic brain anatomy. Diffusion MR images were finally computed from these warped tracts via a composite hindered and restricted model of diffusion with various imaging parameters for gradient directions, image resolution and SNR. Furthermore, an open-source program was developed to evaluate the fiber tracking results both qualitatively and quantitatively based on various similarity measures. PMID:24357914

  12. Fast noninvasive eye-tracking and eye-gaze determination for biomedical and remote monitoring applications

    NASA Astrophysics Data System (ADS)

    Talukder, Ashit; Morookian, John M.; Monacos, Steve P.; Lam, Raymond K.; Lebaw, C.; Bond, A.

    2004-04-01

    Eyetracking is one of the latest technologies that has shown potential in several areas including human-computer interaction for people with and without disabilities, and for noninvasive monitoring, detection, and even diagnosis of physiological and neurological problems in individuals. Current non-invasive eyetracking methods achieve a 30 Hz rate with possibly low accuracy in gaze estimation, that is insufficient for many applications. We propose a new non-invasive visual eyetracking system that is capable of operating at speeds as high as 6-12 KHz. A new CCD video camera and hardware architecture is used, and a novel fast image processing algorithm leverages specific features of the input CCD camera to yield a real-time eyetracking system. A field programmable gate array (FPGA) is used to control the CCD camera and execute the image processing operations. Initial results show the excellent performance of our system under severe head motion and low contrast conditions.

  13. Fast-track extreme event attribution: How fast can we disentangle thermodynamic (forced) and dynamic (internal) contributions?

    NASA Astrophysics Data System (ADS)

    Haustein, Karsten; Otto, Friederike; Uhe, Peter; Allen, Myles; Cullen, Heidi

    2016-04-01

    provide sufficient guidance to determine the dynamic contribution to the event on the basis of monthly mean values. No such link can be made (North Atlantic/Western Europe region) for shorter time-scales, unless the observed state of the circulation is taken as reference for the model analysis (e.g. Christidis et al. 2014). We present results from our most recent attribution analysis for the December 2015 UK floods (Storm Desmond and Eva), during which we find a robust teleconnection link between Pacific SSTs and North Atlantic Jetstream anomalies. This is true for both experiments, with forecast and observed SSTs. We propose a fast and simple analysis method based on the comparison of current climatological circulation patterns with actual and natural conditions. Alternative methods are discussed and analysed regarding their potential for fast-track attribution of the role of dynamics. Also, we briefly revisit the issue of internal vs forced dynamic contributions.

  14. Involuntary motion tracking for medical dynamic infrared thermography using a template-based algorithm

    PubMed Central

    Herman, Cila

    2013-01-01

    In medical applications, Dynamic Infrared (IR) Thermography is used to detect the temporal variation of the skin temperature. Dynamic Infrared Imaging first introduces a thermal challenge such as cooling on the human skin, and then a sequence of hundreds of consecutive frames is acquired after the removal of the thermal challenge. As a result, by analyzing the temporal variation of the skin temperature over the image sequence, the thermal signature of skin abnormality can be examined. However, during the acquisition of dynamic IR imaging, the involuntary movements of patients are unavoidable, and such movements will undermine the accuracy of diagnosis. In this study, based on the template-based algorithm, a tracking approach is proposed to compensate the motion artifact. The affine warping model is adopted to estimate the motion parameter of the image template, and then the Lucas-Kanade algorithm is applied to search for the optimized parameters of the warping function. In addition, the weighting mask is also incorporated in the computation to ensure the robustness of the algorithm. To evaluate the performance of the approach, two sets of IR image sequences of a subject’s hand are analyzed: the steady-state image sequence, in which the skin temperature is in equilibrium with the environment, and the thermal recovery image sequence, which is acquired after cooling is applied on the skin for 60 seconds. By selecting the target region in the first frame as the template, satisfactory tracking results were obtained in both experimental trials, and the robustness of the approach can be effectively ensured in the recovery trial. PMID:24392205

  15. A fast algorithm for exact sequence search in biological sequences using polyphase decomposition

    PubMed Central

    Srikantha, Abhilash; Bopardikar, Ajit S.; Kaipa, Kalyan Kumar; Venkataraman, Parthasarathy; Lee, Kyusang; Ahn, TaeJin; Narayanan, Rangavittal

    2010-01-01

    Motivation: Exact sequence search allows a user to search for a specific DNA subsequence in a larger DNA sequence or database. It serves as a vital block in many areas such as Pharmacogenetics, Phylogenetics and Personal Genomics. As sequencing of genomic data becomes increasingly affordable, the amount of sequence data that must be processed will also increase exponentially. In this context, fast sequence search algorithms will play an important role in exploiting the information contained in the newly sequenced data. Many existing algorithms do not scale up well for large sequences or databases because of their high-computational costs. This article describes an efficient algorithm for performing fast searches on large DNA sequences. It makes use of hash tables of Q-grams that are constructed after downsampling the database, to enable efficient search and memory use. Time complexity for pattern search is reduced using beam pruning techniques. Theoretical complexity calculations and performance figures are presented to indicate the potential of the proposed algorithm. Contact: s.abhilash@samsung.com; ajit.b@samsung.com PMID:20823301

  16. Fast and fully automatic phalanx segmentation using a grayscale-histogram morphology algorithm

    NASA Astrophysics Data System (ADS)

    Hsieh, Chi-Wen; Liu, Tzu-Chiang; Jong, Tai-Lang; Chen, Chih-Yen; Tiu, Chui-Mei; Chan, Din-Yuen

    2011-08-01

    Bone age assessment is a common radiological examination used in pediatrics to diagnose the discrepancy between the skeletal and chronological age of a child; therefore, it is beneficial to develop a computer-based bone age assessment to help junior pediatricians estimate bone age easily. Unfortunately, the phalanx on radiograms is not easily separated from the background and soft tissue. Therefore, we proposed a new method, called the grayscale-histogram morphology algorithm, to segment the phalanges fast and precisely. The algorithm includes three parts: a tri-stage sieve algorithm used to eliminate the background of hand radiograms, a centroid-edge dual scanning algorithm to frame the phalanx region, and finally a segmentation algorithm based on disk traverse-subtraction filter to segment the phalanx. Moreover, two more segmentation methods: adaptive two-mean and adaptive two-mean clustering were performed, and their results were compared with the segmentation algorithm based on disk traverse-subtraction filter using five indices comprising misclassification error, relative foreground area error, modified Hausdorff distances, edge mismatch, and region nonuniformity. In addition, the CPU time of the three segmentation methods was discussed. The result showed that our method had a better performance than the other two methods. Furthermore, satisfactory segmentation results were obtained with a low standard error.

  17. A fast bilinear structure from motion algorithm using a video sequence and inertial sensors.

    PubMed

    Ramachandran, Mahesh; Veeraraghavan, Ashok; Chellappa, Rama

    2011-01-01

    In this paper, we study the benefits of the availability of a specific form of additional information—the vertical direction (gravity) and the height of the camera, both of which can be conveniently measured using inertial sensors and a monocular video sequence for 3D urban modeling. We show that in the presence of this information, the SfM equations can be rewritten in a bilinear form. This allows us to derive a fast, robust, and scalable SfM algorithm for large scale applications. The SfM algorithm developed in this paper is experimentally demonstrated to have favorable properties compared to the sparse bundle adjustment algorithm. We provide experimental evidence indicating that the proposed algorithm converges in many cases to solutions with lower error than state-of-art implementations of bundle adjustment. We also demonstrate that for the case of large reconstruction problems, the proposed algorithm takes lesser time to reach its solution compared to bundle adjustment. We also present SfM results using our algorithm on the Google StreetView research data set. PMID:20733224

  18. Fast Contour-Tracing Algorithm Based on a Pixel-Following Method for Image Sensors

    PubMed Central

    Seo, Jonghoon; Chae, Seungho; Shim, Jinwook; Kim, Dongchul; Cheong, Cheolho; Han, Tack-Don

    2016-01-01

    Contour pixels distinguish objects from the background. Tracing and extracting contour pixels are widely used for smart/wearable image sensor devices, because these are simple and useful for detecting objects. In this paper, we present a novel contour-tracing algorithm for fast and accurate contour following. The proposed algorithm classifies the type of contour pixel, based on its local pattern. Then, it traces the next contour using the previous pixel’s type. Therefore, it can classify the type of contour pixels as a straight line, inner corner, outer corner and inner-outer corner, and it can extract pixels of a specific contour type. Moreover, it can trace contour pixels rapidly because it can determine the local minimal path using the contour case. In addition, the proposed algorithm is capable of the compressing data of contour pixels using the representative points and inner-outer corner points, and it can accurately restore the contour image from the data. To compare the performance of the proposed algorithm to that of conventional techniques, we measure their processing time and accuracy. In the experimental results, the proposed algorithm shows better performance compared to the others. Furthermore, it can provide the compressed data of contour pixels and restore them accurately, including the inner-outer corner, which cannot be restored using conventional algorithms. PMID:27005632

  19. Fast Contour-Tracing Algorithm Based on a Pixel-Following Method for Image Sensors.

    PubMed

    Seo, Jonghoon; Chae, Seungho; Shim, Jinwook; Kim, Dongchul; Cheong, Cheolho; Han, Tack-Don

    2016-01-01

    Contour pixels distinguish objects from the background. Tracing and extracting contour pixels are widely used for smart/wearable image sensor devices, because these are simple and useful for detecting objects. In this paper, we present a novel contour-tracing algorithm for fast and accurate contour following. The proposed algorithm classifies the type of contour pixel, based on its local pattern. Then, it traces the next contour using the previous pixel's type. Therefore, it can classify the type of contour pixels as a straight line, inner corner, outer corner and inner-outer corner, and it can extract pixels of a specific contour type. Moreover, it can trace contour pixels rapidly because it can determine the local minimal path using the contour case. In addition, the proposed algorithm is capable of the compressing data of contour pixels using the representative points and inner-outer corner points, and it can accurately restore the contour image from the data. To compare the performance of the proposed algorithm to that of conventional techniques, we measure their processing time and accuracy. In the experimental results, the proposed algorithm shows better performance compared to the others. Furthermore, it can provide the compressed data of contour pixels and restore them accurately, including the inner-outer corner, which cannot be restored using conventional algorithms. PMID:27005632

  20. Contour detection and completion for inpainting and segmentation based on topological gradient and fast marching algorithms.

    PubMed

    Auroux, Didier; Cohen, Laurent D; Masmoudi, Mohamed

    2011-01-01

    We combine in this paper the topological gradient, which is a powerful method for edge detection in image processing, and a variant of the minimal path method in order to find connected contours. The topological gradient provides a more global analysis of the image than the standard gradient and identifies the main edges of an image. Several image processing problems (e.g., inpainting and segmentation) require continuous contours. For this purpose, we consider the fast marching algorithm in order to find minimal paths in the topological gradient image. This coupled algorithm quickly provides accurate and connected contours. We present then two numerical applications, to image inpainting and segmentation, of this hybrid algorithm. PMID:22194734

  1. A Fast Overlapping Community Detection Algorithm with Self-Correcting Ability

    PubMed Central

    Lu, Nan

    2014-01-01

    Due to the defects of all kinds of modularity, this paper defines a weighted modularity based on the density and cohesion as the new evaluation measurement. Since the proportion of the overlapping nodes in network is very low, the number of the nodes' repeat visits can be reduced by signing the vertices with the overlapping attributes. In this paper, we propose three test conditions for overlapping nodes and present a fast overlapping community detection algorithm with self-correcting ability, which is decomposed into two processes. Under the control of overlapping properties, the complexity of the algorithm tends to be approximate linear. And we also give a new understanding on membership vector. Moreover, we improve the bridgeness function which evaluates the extent of overlapping nodes. Finally, we conduct the experiments on three networks with well known community structures and the results verify the feasibility and effectiveness of our algorithm. PMID:24757434

  2. Fast and accurate analysis of large-scale composite structures with the parallel multilevel fast multipole algorithm.

    PubMed

    Ergül, Özgür; Gürel, Levent

    2013-03-01

    Accurate electromagnetic modeling of complicated optical structures poses several challenges. Optical metamaterial and plasmonic structures are composed of multiple coexisting dielectric and/or conducting parts. Such composite structures may possess diverse values of conductivities and dielectric constants, including negative permittivity and permeability. Further challenges are the large sizes of the structures with respect to wavelength and the complexities of the geometries. In order to overcome these challenges and to achieve rigorous and efficient electromagnetic modeling of three-dimensional optical composite structures, we have developed a parallel implementation of the multilevel fast multipole algorithm (MLFMA). Precise formulation of composite structures is achieved with the so-called "electric and magnetic current combined-field integral equation." Surface integral equations are carefully discretized with piecewise linear basis functions, and the ensuing dense matrix equations are solved iteratively with parallel MLFMA. The hierarchical strategy is used for the efficient parallelization of MLFMA on distributed-memory architectures. In this paper, fast and accurate solutions of large-scale canonical and complicated real-life problems, such as optical metamaterials, discretized with tens of millions of unknowns are presented in order to demonstrate the capabilities of the proposed electromagnetic solver. PMID:23456127

  3. FastGGM: An Efficient Algorithm for the Inference of Gaussian Graphical Model in Biological Networks

    PubMed Central

    Ding, Ying; Fang, Zhou; Sun, Zhe; MacDonald, Matthew L.; Sweet, Robert A.; Wang, Jieru; Chen, Wei

    2016-01-01

    Biological networks provide additional information for the analysis of human diseases, beyond the traditional analysis that focuses on single variables. Gaussian graphical model (GGM), a probability model that characterizes the conditional dependence structure of a set of random variables by a graph, has wide applications in the analysis of biological networks, such as inferring interaction or comparing differential networks. However, existing approaches are either not statistically rigorous or are inefficient for high-dimensional data that include tens of thousands of variables for making inference. In this study, we propose an efficient algorithm to implement the estimation of GGM and obtain p-value and confidence interval for each edge in the graph, based on a recent proposal by Ren et al., 2015. Through simulation studies, we demonstrate that the algorithm is faster by several orders of magnitude than the current implemented algorithm for Ren et al. without losing any accuracy. Then, we apply our algorithm to two real data sets: transcriptomic data from a study of childhood asthma and proteomic data from a study of Alzheimer’s disease. We estimate the global gene or protein interaction networks for the disease and healthy samples. The resulting networks reveal interesting interactions and the differential networks between cases and controls show functional relevance to the diseases. In conclusion, we provide a computationally fast algorithm to implement a statistically sound procedure for constructing Gaussian graphical model and making inference with high-dimensional biological data. The algorithm has been implemented in an R package named “FastGGM”. PMID:26872036

  4. A fast implementation of the incremental backprojection algorithms for parallel beam geometries

    SciTech Connect

    Chen, C.M.; Wang, C.Y.; Cho, Z.H.

    1996-12-01

    Filtered-backprojection algorithms are the most widely used approaches for reconstruction of computed tomographic (CT) images, such as X-ray CT and positron emission tomographic (PET) images. The Incremental backprojection algorithm is a fast backprojection approach based on restructuring the Shepp and Logan algorithm. By exploiting interdependency (position and values) of adjacent pixels, the Incremental algorithm requires only O(N) and O(N{sup 2}) multiplications in contrast to O(N{sup 2}) and O(N{sup 3}) multiplications for the Shepp and Logan algorithm in two-dimensional (2-D) and three-dimensional (3-D) backprojections, respectively, for each view, where N is the size of the image in each dimension. In addition, it may reduce the number of additions for each pixel computation. The improvement achieved by the Incremental algorithm in practice was not, however, as significant as expected. One of the main reasons is due to inevitably visiting pixels outside the beam in the searching flow scheme originally developed for the Incremental algorithm. To optimize implementation of the Incremental algorithm, an efficient scheme, namely, coded searching flow scheme, is proposed in this paper to minimize the overhead caused by searching for all pixels in a beam. The key idea of this scheme is to encode the searching flow for all pixels inside each beam. While backprojecting, all pixels may be visited without any overhead due to using the coded searching flow as the a priori information. The proposed coded searching flow scheme has been implemented on a Sun Sparc 10 and a Sun Sparc 20 workstations. The implementation results show that the proposed scheme is 1.45--2.0 times faster than the original searching flow scheme for most cases tested.

  5. [Anxiety in patients undergoing fast-track knee arthroplasty in the light of recent literature].

    PubMed

    Ziętek, Paweł; Ziętek, Joanna; Szczypiór, Karina

    2014-01-01

    The rapid progress in knee implants technology and operational techniques go together with more and more modem medical programs, designed to optimize the patients' care and shorten their stay in hospital. However, this does not guarantee any elimination ofperioperative stress in patients. Anxiety is a negative emotional state arising from stressful circumstances accompanied by activation of the autonomous nervous system. Anxiety causes negative physiological changes, including wound healing, resistance to anesthetic induction, it is associated with an increased perioperative pain and prolong recovery period. The purpose of this work is to present the current state of knowledge on the preoperative anxiety and discuss its impact on pain and other parameters in patients undergoing fast-track arthroplasty of big joints. The work also shows selected issues of anxiety pathomechanism, and actual methods reducing preoperative anxiety in hospitalized patients. The common prevalence of anxiety in patients undergoing surgery induces the attempt to routinely identify patients with higher anxiety, which may be a predictive factor of worse results after TKA. Undertaking widely understood psychological support in these patients before and after the operation could be a favorable element, which would influence thefinal result of the treatment of patients after big joints arthroplasties. PMID:25639020

  6. Statistical iterative reconstruction using fast optimization transfer algorithm with successively increasing factor in Digital Breast Tomosynthesis

    NASA Astrophysics Data System (ADS)

    Xu, Shiyu; Zhang, Zhenxi; Chen, Ying

    2014-03-01

    Statistical iterative reconstruction exhibits particularly promising since it provides the flexibility of accurate physical noise modeling and geometric system description in transmission tomography system. However, to solve the objective function is computationally intensive compared to analytical reconstruction methods due to multiple iterations needed for convergence and each iteration involving forward/back-projections by using a complex geometric system model. Optimization transfer (OT) is a general algorithm converting a high dimensional optimization to a parallel 1-D update. OT-based algorithm provides a monotonic convergence and a parallel computing framework but slower convergence rate especially around the global optimal. Based on an indirect estimation on the spectrum of the OT convergence rate matrix, we proposed a successively increasing factor- scaled optimization transfer (OT) algorithm to seek an optimal step size for a faster rate. Compared to a representative OT based method such as separable parabolic surrogate with pre-computed curvature (PC-SPS), our algorithm provides comparable image quality (IQ) with fewer iterations. Each iteration retains a similar computational cost to PC-SPS. The initial experiment with a simulated Digital Breast Tomosynthesis (DBT) system shows that a total 40% computing time is saved by the proposed algorithm. In general, the successively increasing factor-scaled OT exhibits a tremendous potential to be a iterative method with a parallel computation, a monotonic and global convergence with fast rate.

  7. Fast Adapting Ensemble: A New Algorithm for Mining Data Streams with Concept Drift

    PubMed Central

    Ortíz Díaz, Agustín; Ramos-Jiménez, Gonzalo; Frías Blanco, Isvani; Caballero Mota, Yailé; Morales-Bueno, Rafael

    2015-01-01

    The treatment of large data streams in the presence of concept drifts is one of the main challenges in the field of data mining, particularly when the algorithms have to deal with concepts that disappear and then reappear. This paper presents a new algorithm, called Fast Adapting Ensemble (FAE), which adapts very quickly to both abrupt and gradual concept drifts, and has been specifically designed to deal with recurring concepts. FAE processes the learning examples in blocks of the same size, but it does not have to wait for the batch to be complete in order to adapt its base classification mechanism. FAE incorporates a drift detector to improve the handling of abrupt concept drifts and stores a set of inactive classifiers that represent old concepts, which are activated very quickly when these concepts reappear. We compare our new algorithm with various well-known learning algorithms, taking into account, common benchmark datasets. The experiments show promising results from the proposed algorithm (regarding accuracy and runtime), handling different types of concept drifts. PMID:25879051

  8. Fast instantaneous center of rotation estimation algorithm for a skied-steered robot

    NASA Astrophysics Data System (ADS)

    Kniaz, V. V.

    2015-05-01

    Skid-steered robots are widely used as mobile platforms for machine vision systems. However it is hard to achieve a stable motion of such robots along desired trajectory due to an unpredictable wheel slip. It is possible to compensate the unpredictable wheel slip and stabilize the motion of the robot using visual odometry. This paper presents a fast optical flow based algorithm for estimation of instantaneous center of rotation, angular and longitudinal speed of the robot. The proposed algorithm is based on Horn-Schunck variational optical flow estimation method. The instantaneous center of rotation and motion of the robot is estimated by back projection of optical flow field to the ground surface. The developed algorithm was tested using skid-steered mobile robot. The robot is based on a mobile platform that includes two pairs of differential driven motors and a motor controller. Monocular visual odometry system consisting of a singleboard computer and a low cost webcam is mounted on the mobile platform. A state-space model of the robot was derived using standard black-box system identification. The input (commands) and the output (motion) were recorded using a dedicated external motion capture system. The obtained model was used to control the robot without visual odometry data. The paper is concluded with the algorithm quality estimation by comparison of the trajectories estimated by the algorithm with the data from motion capture system.

  9. Fast automated yeast cell counting algorithm using bright-field and fluorescence microscopic images

    PubMed Central

    2013-01-01

    Background The faithful determination of the concentration and viability of yeast cells is important for biological research as well as industry. To this end, it is important to develop an automated cell counting algorithm that can provide not only fast but also accurate and precise measurement of yeast cells. Results With the proposed method, we measured the precision of yeast cell measurements by using 0%, 25%, 50%, 75% and 100% viability samples. As a result, the actual viability measured with the proposed yeast cell counting algorithm is significantly correlated to the theoretical viability (R2 = 0.9991). Furthermore, we evaluated the performance of our algorithm in various computing platforms. The results showed that the proposed algorithm could be feasible to use with low-end computing platforms without loss of its performance. Conclusions Our yeast cell counting algorithm can rapidly provide the total number and the viability of yeast cells with exceptional accuracy and precision. Therefore, we believe that our method can become beneficial for a wide variety of academic field and industries such as biotechnology, pharmaceutical and alcohol production. PMID:24215650

  10. Fast algorithm for scaling analysis with higher-order detrending moving average method

    NASA Astrophysics Data System (ADS)

    Tsujimoto, Yutaka; Miki, Yuki; Shimatani, Satoshi; Kiyono, Ken

    2016-05-01

    Among scaling analysis methods based on the root-mean-square deviation from the estimated trend, it has been demonstrated that centered detrending moving average (DMA) analysis with a simple moving average has good performance when characterizing long-range correlation or fractal scaling behavior. Furthermore, higher-order DMA has also been proposed; it is shown to have better detrending capabilities, removing higher-order polynomial trends than original DMA. However, a straightforward implementation of higher-order DMA requires a very high computational cost, which would prevent practical use of this method. To solve this issue, in this study, we introduce a fast algorithm for higher-order DMA, which consists of two techniques: (1) parallel translation of moving averaging windows by a fixed interval; (2) recurrence formulas for the calculation of summations. Our algorithm can significantly reduce computational cost. Monte Carlo experiments show that the computational time of our algorithm is approximately proportional to the data length, although that of the conventional algorithm is proportional to the square of the data length. The efficiency of our algorithm is also shown by a systematic study of the performance of higher-order DMA, such as the range of detectable scaling exponents and detrending capability for removing polynomial trends. In addition, through the analysis of heart-rate variability time series, we discuss possible applications of higher-order DMA.

  11. A fast rank-reduction algorithm for three-dimensional seismic data interpolation

    NASA Astrophysics Data System (ADS)

    Jia, Yongna; Yu, Siwei; Liu, Lina; Ma, Jianwei

    2016-09-01

    Rank-reduction methods have been successfully used for seismic data interpolation and noise attenuation. However, highly intense computation is required for singular value decomposition (SVD) in most rank-reduction methods. In this paper, we propose a simple yet efficient interpolation algorithm, which is based on the Hankel matrix, for randomly missing traces. Following the multichannel singular spectrum analysis (MSSA) technique, we first transform the seismic data into a low-rank block Hankel matrix for each frequency slice. Then, a fast orthogonal rank-one matrix pursuit (OR1MP) algorithm is employed to minimize the low-rank constraint of the block Hankel matrix. In the new algorithm, only the left and right top singular vectors are needed to be computed, thereby, avoiding the complexity of computation required for SVD. Thus, we improve the calculation efficiency significantly. Finally, we anti-average the rank-reduction block Hankel matrix and obtain the reconstructed data in the frequency domain. Numerical experiments on 3D seismic data show that the proposed interpolation algorithm provides much better performance than the traditional MSSA algorithm in computational speed, especially for large-scale data processing.

  12. Fast dose algorithm for generation of dose coverage probability for robustness analysis of fractionated radiotherapy

    NASA Astrophysics Data System (ADS)

    Tilly, David; Ahnesjö, Anders

    2015-07-01

    A fast algorithm is constructed to facilitate dose calculation for a large number of randomly sampled treatment scenarios, each representing a possible realisation of a full treatment with geometric, fraction specific displacements for an arbitrary number of fractions. The algorithm is applied to construct a dose volume coverage probability map (DVCM) based on dose calculated for several hundred treatment scenarios to enable the probabilistic evaluation of a treatment plan. For each treatment scenario, the algorithm calculates the total dose by perturbing a pre-calculated dose, separately for the primary and scatter dose components, for the nominal conditions. The ratio of the scenario specific accumulated fluence, and the average fluence for an infinite number of fractions is used to perturb the pre-calculated dose. Irregularities in the accumulated fluence may cause numerical instabilities in the ratio, which is mitigated by regularisation through convolution with a dose pencil kernel. Compared to full dose calculations the algorithm demonstrates a speedup factor of ~1000. The comparisons to full calculations show a 99% gamma index (2%/2 mm) pass rate for a single highly modulated beam in a virtual water phantom subject to setup errors during five fractions. The gamma comparison shows a 100% pass rate in a moving tumour irradiated by a single beam in a lung-like virtual phantom. DVCM iso-probability lines computed with the fast algorithm, and with full dose calculation for each of the fractions, for a hypo-fractionated prostate case treated with rotational arc therapy treatment were almost indistinguishable.

  13. Fast dose algorithm for generation of dose coverage probability for robustness analysis of fractionated radiotherapy.

    PubMed

    Tilly, David; Ahnesjö, Anders

    2015-07-21

    A fast algorithm is constructed to facilitate dose calculation for a large number of randomly sampled treatment scenarios, each representing a possible realisation of a full treatment with geometric, fraction specific displacements for an arbitrary number of fractions. The algorithm is applied to construct a dose volume coverage probability map (DVCM) based on dose calculated for several hundred treatment scenarios to enable the probabilistic evaluation of a treatment plan.For each treatment scenario, the algorithm calculates the total dose by perturbing a pre-calculated dose, separately for the primary and scatter dose components, for the nominal conditions. The ratio of the scenario specific accumulated fluence, and the average fluence for an infinite number of fractions is used to perturb the pre-calculated dose. Irregularities in the accumulated fluence may cause numerical instabilities in the ratio, which is mitigated by regularisation through convolution with a dose pencil kernel.Compared to full dose calculations the algorithm demonstrates a speedup factor of ~1000. The comparisons to full calculations show a 99% gamma index (2%/2 mm) pass rate for a single highly modulated beam in a virtual water phantom subject to setup errors during five fractions. The gamma comparison shows a 100% pass rate in a moving tumour irradiated by a single beam in a lung-like virtual phantom. DVCM iso-probability lines computed with the fast algorithm, and with full dose calculation for each of the fractions, for a hypo-fractionated prostate case treated with rotational arc therapy treatment were almost indistinguishable. PMID:26118844

  14. Generation of fast neturon spectra using an adaptive Gauss-Kronrod Quadrature algorithm

    NASA Astrophysics Data System (ADS)

    Triplett, Brian Scott

    A lattice physics calculation is often the first step in analyzing a nuclear reactor. This calculation condenses regions of the reactor into average parameters (i.e., group constants) that can be used in coarser full-core, time-dependent calculations. This work presents a high-fidelity deterministic method for calculating the neutron energy spectrum in an infinite medium. The spectrum resulting from this calculation can be used to generate accurate group constants. This method includes a numerical algorithm based on Gauss-Kronrod Quadrature to determine the neutron transfer source to a given energy while controlling numerical error. This algorithm was implemented in a pointwise transport solver program called Pointwise Fast Spectrum Generator (PWFSG). PWFSG was benchmarked against the Monte Carlo program MCNP and another pointwise spectrum generation program, CENTRM, for a set of fast reactor infinite medium example cases. PWFSG showed good agreement with MCNP, yielding coefficients of determination above 98% for all example cases. In addition, PWFSG had 6 to 8 times lower flux estimation error than CENTRM in the cases examined. With run-times comparable to CENTRM, PWFSG represents a robust set of methods for generation of fast neutron spectra with increased accuracy without increased computational cost.

  15. A Fast and Precise Indoor Localization Algorithm Based on an Online Sequential Extreme Learning Machine †

    PubMed Central

    Zou, Han; Lu, Xiaoxuan; Jiang, Hao; Xie, Lihua

    2015-01-01

    Nowadays, developing indoor positioning systems (IPSs) has become an attractive research topic due to the increasing demands on location-based service (LBS) in indoor environments. WiFi technology has been studied and explored to provide indoor positioning service for years in view of the wide deployment and availability of existing WiFi infrastructures in indoor environments. A large body of WiFi-based IPSs adopt fingerprinting approaches for localization. However, these IPSs suffer from two major problems: the intensive costs of manpower and time for offline site survey and the inflexibility to environmental dynamics. In this paper, we propose an indoor localization algorithm based on an online sequential extreme learning machine (OS-ELM) to address the above problems accordingly. The fast learning speed of OS-ELM can reduce the time and manpower costs for the offline site survey. Meanwhile, its online sequential learning ability enables the proposed localization algorithm to adapt in a timely manner to environmental dynamics. Experiments under specific environmental changes, such as variations of occupancy distribution and events of opening or closing of doors, are conducted to evaluate the performance of OS-ELM. The simulation and experimental results show that the proposed localization algorithm can provide higher localization accuracy than traditional approaches, due to its fast adaptation to various environmental dynamics. PMID:25599427

  16. A hierarchical algorithm for fast Debye summation with applications to small angle scattering.

    PubMed

    Gumerov, Nail A; Berlin, Konstantin; Fushman, David; Duraiswami, Ramani

    2012-09-30

    Debye summation, which involves the summation of sinc functions of distances between all pair of atoms in three-dimensional space, arises in computations performed in crystallography, small/wide angle X-ray scattering (SAXS/WAXS), and small angle neutron scattering (SANS). Direct evaluation of Debye summation has quadratic complexity, which results in computational bottleneck when determining crystal properties, or running structure refinement protocols that involve SAXS or SANS, even for moderately sized molecules. We present a fast approximation algorithm that efficiently computes the summation to any prescribed accuracy ε in linear time. The algorithm is similar to the fast multipole method (FMM), and is based on a hierarchical spatial decomposition of the molecule coupled with local harmonic expansions and translation of these expansions. An even more efficient implementation is possible when the scattering profile is all that is required, as in small angle scattering reconstruction (SAS) of macromolecules. We examine the relationship of the proposed algorithm to existing approximate methods for profile computations, and show that these methods may result in inaccurate profile computations, unless an error-bound derived in this article is used. Our theoretical and computational results show orders of magnitude improvement in computation complexity over existing methods, while maintaining prescribed accuracy. PMID:22707386

  17. A fast and precise indoor localization algorithm based on an online sequential extreme learning machine.

    PubMed

    Zou, Han; Lu, Xiaoxuan; Jiang, Hao; Xie, Lihua

    2015-01-01

    Nowadays, developing indoor positioning systems (IPSs) has become an attractive research topic due to the increasing demands on location-based service (LBS) in indoor environments. WiFi technology has been studied and explored to provide indoor positioning service for years in view of the wide deployment and availability of existing WiFi infrastructures in indoor environments. A large body of WiFi-based IPSs adopt fingerprinting approaches for localization. However, these IPSs suffer from two major problems: the intensive costs of manpower and time for offline site survey and the inflexibility to environmental dynamics. In this paper, we propose an indoor localization algorithm based on an online sequential extreme learning machine (OS-ELM) to address the above problems accordingly. The fast learning speed of OS-ELM can reduce the time and manpower costs for the offline site survey. Meanwhile, its online sequential learning ability enables the proposed localization algorithm to adapt in a timely manner to environmental dynamics. Experiments under specific environmental changes, such as variations of occupancy distribution and events of opening or closing of doors, are conducted to evaluate the performance of OS-ELM. The simulation and experimental results show that the proposed localization algorithm can provide higher localization accuracy than traditional approaches, due to its fast adaptation to various environmental dynamics. PMID:25599427

  18. Imaging biomolecular interactions by fast three-dimensional tracking of laser-confined carrier particles.

    PubMed

    Heinrich, Volkmar; Wong, Wesley P; Halvorsen, Ken; Evans, Evan

    2008-02-19

    The quantitative study of the near-equilibrium structural behavior of individual biomolecules requires high-resolution experimental approaches with longtime stability. We present a new technique to explore the dynamics of weak intramolecular interactions. It is based on the analysis of the 3D Brownian fluctuations of a laser-confined glass bead that is tethered to a flat surface by the biomolecule of interest. A continuous autofocusing mechanism allows us to maintain or adjust the height of the optical trap with nanometer accuracy over long periods of time. The resulting remarkably stable trapping potential adds a well-defined femto-to-piconewton force bias to the energy landscape of molecular configurations. A combination of optical interferometry and advanced pattern-tracking algorithms provides the 3D bead positions with nanometer spatial and >120 Hz temporal resolution. The analysis of accumulated 3D positions has allowed us not only to identify small single biomolecules but also to characterize their nanomechanical behavior, for example, the force-extension relations of short oligonucleotides and the unfolding/refolding transitions of small protein tethers. PMID:18198910

  19. A Fast Robot Identification and Mapping Algorithm Based on Kinect Sensor

    PubMed Central

    Zhang, Liang; Shen, Peiyi; Zhu, Guangming; Wei, Wei; Song, Houbing

    2015-01-01

    Internet of Things (IoT) is driving innovation in an ever-growing set of application domains such as intelligent processing for autonomous robots. For an autonomous robot, one grand challenge is how to sense its surrounding environment effectively. The Simultaneous Localization and Mapping with RGB-D Kinect camera sensor on robot, called RGB-D SLAM, has been developed for this purpose but some technical challenges must be addressed. Firstly, the efficiency of the algorithm cannot satisfy real-time requirements; secondly, the accuracy of the algorithm is unacceptable. In order to address these challenges, this paper proposes a set of novel improvement methods as follows. Firstly, the ORiented Brief (ORB) method is used in feature detection and descriptor extraction. Secondly, a bidirectional Fast Library for Approximate Nearest Neighbors (FLANN) k-Nearest Neighbor (KNN) algorithm is applied to feature match. Then, the improved RANdom SAmple Consensus (RANSAC) estimation method is adopted in the motion transformation. In the meantime, high precision General Iterative Closest Points (GICP) is utilized to register a point cloud in the motion transformation optimization. To improve the accuracy of SLAM, the reduced dynamic covariance scaling (DCS) algorithm is formulated as a global optimization problem under the G2O framework. The effectiveness of the improved algorithm has been verified by testing on standard data and comparing with the ground truth obtained on Freiburg University’s datasets. The Dr Robot X80 equipped with a Kinect camera is also applied in a building corridor to verify the correctness of the improved RGB-D SLAM algorithm. With the above experiments, it can be seen that the proposed algorithm achieves higher processing speed and better accuracy. PMID:26287198

  20. A Fast Robot Identification and Mapping Algorithm Based on Kinect Sensor.

    PubMed

    Zhang, Liang; Shen, Peiyi; Zhu, Guangming; Wei, Wei; Song, Houbing

    2015-01-01

    Internet of Things (IoT) is driving innovation in an ever-growing set of application domains such as intelligent processing for autonomous robots. For an autonomous robot, one grand challenge is how to sense its surrounding environment effectively. The Simultaneous Localization and Mapping with RGB-D Kinect camera sensor on robot, called RGB-D SLAM, has been developed for this purpose but some technical challenges must be addressed. Firstly, the efficiency of the algorithm cannot satisfy real-time requirements; secondly, the accuracy of the algorithm is unacceptable. In order to address these challenges, this paper proposes a set of novel improvement methods as follows. Firstly, the ORiented Brief (ORB) method is used in feature detection and descriptor extraction. Secondly, a bidirectional Fast Library for Approximate Nearest Neighbors (FLANN) k-Nearest Neighbor (KNN) algorithm is applied to feature match. Then, the improved RANdom SAmple Consensus (RANSAC) estimation method is adopted in the motion transformation. In the meantime, high precision General Iterative Closest Points (GICP) is utilized to register a point cloud in the motion transformation optimization. To improve the accuracy of SLAM, the reduced dynamic covariance scaling (DCS) algorithm is formulated as a global optimization problem under the G2O framework. The effectiveness of the improved algorithm has been verified by testing on standard data and comparing with the ground truth obtained on Freiburg University's datasets. The Dr Robot X80 equipped with a Kinect camera is also applied in a building corridor to verify the correctness of the improved RGB-D SLAM algorithm. With the above experiments, it can be seen that the proposed algorithm achieves higher processing speed and better accuracy. PMID:26287198

  1. Modeling and control of a two-axis fast steering mirror with piezoelectric stack actuators for laser beam tracking

    NASA Astrophysics Data System (ADS)

    Zhu, Wei; Bian, Leixiang; An, Yi; Chen, Gangli; Rui, Xiaoting

    2015-07-01

    This paper outlines an optical beam steering system built using a two-axis fast steering mirror (FSM) with piezoelectric stack actuators to maintain precise pointing control. A novel mathematical model of the FSM is put forward by using a transfer matrix method of a multibody system to describe the dynamics characteristics and a hysteresis model to represent the hysteresis. Based on the proposed model, a model-based hybrid control is applied to force the output angle of the FSM to track the laser beam accurately thereafter. The experimental results are in accordance with the theoretical analysis. The results highlight significantly improved accuracy in the beam tracking control of the FSM.

  2. Time-resolved observation of fast domain-walls driven by vertical spin currents in short tracks

    NASA Astrophysics Data System (ADS)

    Sampaio, Joao; Lequeux, Steven; Metaxas, Peter J.; Chanthbouala, Andre; Matsumoto, Rie; Yakushiji, Kay; Kubota, Hitoshi; Fukushima, Akio; Yuasa, Shinji; Nishimura, Kazumasa; Nagamine, Yoshinori; Maehara, Hiroki; Tsunekawa, Koji; Cros, Vincent; Grollier, Julie

    2013-12-01

    We present time-resolved measurements of the displacement of magnetic domain-walls (DWs) driven by vertical spin-polarized currents in track-shaped magnetic tunnel junctions. In these structures, we observe very high DW velocities (600 m/s) at current densities below 107 A/cm2. We show that the efficient spin-transfer torque combined with a short propagation distance allows avoiding the Walker breakdown process and achieving deterministic, reversible, and fast (≈1 ns) DW-mediated switching of magnetic tunnel junction elements, which is of great interest for the implementation of fast DW-based spintronic devices.

  3. Time-resolved observation of fast domain-walls driven by vertical spin currents in short tracks

    SciTech Connect

    Sampaio, Joao; Lequeux, Steven; Chanthbouala, Andre; Cros, Vincent; Grollier, Julie; Matsumoto, Rie; Yakushiji, Kay; Kubota, Hitoshi; Fukushima, Akio; Yuasa, Shinji; Nishimura, Kazumasa; Nagamine, Yoshinori; Maehara, Hiroki; Tsunekawa, Koji

    2013-12-09

    We present time-resolved measurements of the displacement of magnetic domain-walls (DWs) driven by vertical spin-polarized currents in track-shaped magnetic tunnel junctions. In these structures, we observe very high DW velocities (600 m/s) at current densities below 10{sup 7} A/cm{sup 2}. We show that the efficient spin-transfer torque combined with a short propagation distance allows avoiding the Walker breakdown process and achieving deterministic, reversible, and fast (≈1 ns) DW-mediated switching of magnetic tunnel junction elements, which is of great interest for the implementation of fast DW-based spintronic devices.

  4. Reliability and accuracy of an automated tracking algorithm to measure controlled passive and active muscle fascicle length changes from ultrasound.

    PubMed

    Gillett, Jarred G; Barrett, Rod S; Lichtwark, Glen A

    2013-01-01

    Manual tracking of muscle fascicle length changes from ultrasound images is a subjective and time-consuming process. The purpose of this study was to assess the repeatability and accuracy of an automated algorithm for tracking fascicle length changes in the medial gastrocnemius (MG) muscle during passive length changes and active contractions (isometric, concentric and eccentric) performed on a dynamometer. The freely available, automated tracking algorithm was based on the Lucas-Kanade optical flow algorithm with an affine optic flow extension, which accounts for image translation, dilation, rotation and shear between consecutive frames of an image sequence. Automated tracking was performed by three experienced assessors, and within- and between-examiner repeatability was computed using the coefficient of multiple determination (CMD). Fascicle tracking data were also compared with manual digitisation of the same image sequences, and the level of agreement between the two methods was calculated using the coefficient of multiple correlation (CMC). The CMDs across all test conditions ranged from 0.50 to 0.93 and were all above 0.98 when recomputed after the systematic error due to the estimate of the initial fascicle length on the first ultrasound frame was removed from the individual fascicle length waveforms. The automated and manual tracking approaches produced similar fascicle length waveforms, with an overall CMC of 0.88, which improved to 0.94 when the initial length offset was removed. Overall results indicate that the automated fascicle tracking algorithm was a repeatable, accurate and time-efficient method for estimating fascicle length changes of the MG muscle in controlled passive and active conditions. PMID:22235878

  5. Performance Evaluation of Block Acquisition and Tracking Algorithms Using an Open Source GPS Receiver Platform

    NASA Technical Reports Server (NTRS)

    Ramachandran, Ganesh K.; Akopian, David; Heckler, Gregory W.; Winternitz, Luke B.

    2011-01-01

    Location technologies have many applications in wireless communications, military and space missions, etc. US Global Positioning System (GPS) and other existing and emerging Global Navigation Satellite Systems (GNSS) are expected to provide accurate location information to enable such applications. While GNSS systems perform very well in strong signal conditions, their operation in many urban, indoor, and space applications is not robust or even impossible due to weak signals and strong distortions. The search for less costly, faster and more sensitive receivers is still in progress. As the research community addresses more and more complicated phenomena there exists a demand on flexible multimode reference receivers, associated SDKs, and development platforms which may accelerate and facilitate the research. One of such concepts is the software GPS/GNSS receiver (GPS SDR) which permits a facilitated access to algorithmic libraries and a possibility to integrate more advanced algorithms without hardware and essential software updates. The GNU-SDR and GPS-SDR open source receiver platforms are such popular examples. This paper evaluates the performance of recently proposed block-corelator techniques for acquisition and tracking of GPS signals using open source GPS-SDR platform.

  6. Algorithms for Accurate and Fast Plotting of Contour Surfaces in 3D Using Hexahedral Elements

    NASA Astrophysics Data System (ADS)

    Singh, Chandan; Saini, Jaswinder Singh

    2016-07-01

    In the present study, Fast and accurate algorithms for the generation of contour surfaces in 3D are described using hexahedral elements which are popular in finite element analysis. The contour surfaces are described in the form of groups of boundaries of contour segments and their interior points are derived using the contour equation. The locations of contour boundaries and the interior points on contour surfaces are as accurate as the interpolation results obtained by hexahedral elements and thus there are no discrepancies between the analysis and visualization results.

  7. A Generalized Fast Frequency Sweep Algorithm for Coupled Circuit-EM Simulations

    SciTech Connect

    Ouyang, G; Jandhyala, V; Champagne, N; Sharpe, R; Fasenfest, B J; Rockway, J D

    2004-12-14

    An Asymptotic Wave Expansion (AWE) technique is implemented into the EIGER computational electromagnetics code. The AWE fast frequency sweep is formed by separating the components of the integral equations by frequency dependence, then using this information to find a rational function approximation of the results. The standard AWE method is generalized to work for several integral equations, including the EFIE for conductors and the PMCHWT for dielectrics. The method is also expanded to work for two types of coupled circuit-EM problems as well as lumped load circuit elements. After a simple bisecting adaptive sweep algorithm is developed, dramatic speed improvements are seen for several example problems.

  8. Algorithms for Accurate and Fast Plotting of Contour Surfaces in 3D Using Hexahedral Elements

    NASA Astrophysics Data System (ADS)

    Singh, Chandan; Saini, Jaswinder Singh

    2016-05-01

    In the present study, Fast and accurate algorithms for the generation of contour surfaces in 3D are described using hexahedral elements which are popular in finite element analysis. The contour surfaces are described in the form of groups of boundaries of contour segments and their interior points are derived using the contour equation. The locations of contour boundaries and the interior points on contour surfaces are as accurate as the interpolation results obtained by hexahedral elements and thus there are no discrepancies between the analysis and visualization results.

  9. How Fast Is Your Body Motion? Determining a Sufficient Frame Rate for an Optical Motion Tracking System Using Passive Markers.

    PubMed

    Song, Min-Ho; Godøy, Rolf Inge

    2016-01-01

    This paper addresses how to determine a sufficient frame (sampling) rate for an optical motion tracking system using passive reflective markers. When using passive markers for the optical motion tracking, avoiding identity confusion between the markers becomes a problem as the speed of motion increases, necessitating a higher frame rate to avoid a failure of the motion tracking caused by marker confusions and/or dropouts. Initially, one might believe that the Nyquist-Shannon sampling rate estimated from the assumed maximal temporal variation of a motion (i.e. a sampling rate at least twice that of the maximum motion frequency) could be the complete solution to the problem. However, this paper shows that also the spatial distance between the markers should be taken into account in determining the suitable frame rate of an optical motion tracking with passive markers. In this paper, a frame rate criterion for the optical tracking using passive markers is theoretically derived and also experimentally verified using a high-quality optical motion tracking system. Both the theoretical and the experimental results showed that the minimum frame rate is proportional to the ratio between the maximum speed of the motion and the minimum spacing between markers, and may also be predicted precisely if the proportional constant is known in advance. The inverse of the proportional constant is here defined as the tracking efficiency constant and it can be easily determined with some test measurements. Moreover, this newly defined constant can provide a new way of evaluating the tracking algorithm performance of an optical tracking system. PMID:26967900

  10. How Fast Is Your Body Motion? Determining a Sufficient Frame Rate for an Optical Motion Tracking System Using Passive Markers

    PubMed Central

    Song, Min-Ho; Godøy, Rolf Inge

    2016-01-01

    This paper addresses how to determine a sufficient frame (sampling) rate for an optical motion tracking system using passive reflective markers. When using passive markers for the optical motion tracking, avoiding identity confusion between the markers becomes a problem as the speed of motion increases, necessitating a higher frame rate to avoid a failure of the motion tracking caused by marker confusions and/or dropouts. Initially, one might believe that the Nyquist-Shannon sampling rate estimated from the assumed maximal temporal variation of a motion (i.e. a sampling rate at least twice that of the maximum motion frequency) could be the complete solution to the problem. However, this paper shows that also the spatial distance between the markers should be taken into account in determining the suitable frame rate of an optical motion tracking with passive markers. In this paper, a frame rate criterion for the optical tracking using passive markers is theoretically derived and also experimentally verified using a high-quality optical motion tracking system. Both the theoretical and the experimental results showed that the minimum frame rate is proportional to the ratio between the maximum speed of the motion and the minimum spacing between markers, and may also be predicted precisely if the proportional constant is known in advance. The inverse of the proportional constant is here defined as the tracking efficiency constant and it can be easily determined with some test measurements. Moreover, this newly defined constant can provide a new way of evaluating the tracking algorithm performance of an optical tracking system. PMID:26967900

  11. Lazy skip-lists: An algorithm for fast hybridization-expansion quantum Monte Carlo

    NASA Astrophysics Data System (ADS)

    Sémon, P.; Yee, Chuck-Hou; Haule, Kristjan; Tremblay, A.-M. S.

    2014-08-01

    The solution of a generalized impurity model lies at the heart of electronic structure calculations with dynamical mean field theory. In the strongly correlated regime, the method of choice for solving the impurity model is the hybridization-expansion continuous-time quantum Monte Carlo (CT-HYB). Enhancements to the CT-HYB algorithm are critical for bringing new physical regimes within reach of current computational power. Taking advantage of the fact that the bottleneck in the algorithm is a product of hundreds of matrices, we present optimizations based on the introduction and combination of two concepts of more general applicability: (a) skip lists and (b) fast rejection of proposed configurations based on matrix bounds. Considering two very different test cases with d electrons, we find speedups of ˜25 up to ˜500 compared to the direct evaluation of the matrix product. Even larger speedups are likely with f electron systems and with clusters of correlated atoms.

  12. ADaM: augmenting existing approximate fast matching algorithms with efficient and exact range queries

    PubMed Central

    2014-01-01

    Background Drug discovery, disease detection, and personalized medicine are fast-growing areas of genomic research. With the advancement of next-generation sequencing techniques, researchers can obtain an abundance of data for many different biological assays in a short period of time. When this data is error-free, the result is a high-quality base-pair resolution picture of the genome. However, when the data is lossy the heuristic algorithms currently used when aligning next-generation sequences causes the corresponding accuracy to drop. Results This paper describes a program, ADaM (APF DNA Mapper) which significantly increases final alignment accuracy. ADaM works by first using an existing program to align "easy" sequences, and then using an algorithm with accuracy guarantees (the APF) to align the remaining sequences. The final result is a technique that increases the mapping accuracy from only 60% to over 90% for harder-to-align sequences. PMID:25079667

  13. A fast high-order finite difference algorithm for pricing American options

    NASA Astrophysics Data System (ADS)

    Tangman, D. Y.; Gopaul, A.; Bhuruth, M.

    2008-12-01

    We describe an improvement of Han and Wu's algorithm [H. Han, X.Wu, A fast numerical method for the Black-Scholes equation of American options, SIAM J. Numer. Anal. 41 (6) (2003) 2081-2095] for American options. A high-order optimal compact scheme is used to discretise the transformed Black-Scholes PDE under a singularity separating framework. A more accurate free boundary location based on the smooth pasting condition and the use of a non-uniform grid with a modified tridiagonal solver lead to an efficient implementation of the free boundary value problem. Extensive numerical experiments show that the new finite difference algorithm converges rapidly and numerical solutions with good accuracy are obtained. Comparisons with some recently proposed methods for the American options problem are carried out to show the advantage of our numerical method.

  14. A fast sorting algorithm for a hypersonic rarefied flow particle simulation on the connection machine

    NASA Technical Reports Server (NTRS)

    Dagum, Leonardo

    1989-01-01

    The data parallel implementation of a particle simulation for hypersonic rarefied flow described by Dagum associates a single parallel data element with each particle in the simulation. The simulated space is divided into discrete regions called cells containing a variable and constantly changing number of particles. The implementation requires a global sort of the parallel data elements so as to arrange them in an order that allows immediate access to the information associated with cells in the simulation. Described here is a very fast algorithm for performing the necessary ranking of the parallel data elements. The performance of the new algorithm is compared with that of the microcoded instruction for ranking on the Connection Machine.

  15. Hessian Schatten-norm regularization for CBCT image reconstruction using fast iterative shrinkage-thresholding algorithm

    NASA Astrophysics Data System (ADS)

    Li, Xinxin; Wang, Jiang; Tan, Shan

    2015-03-01

    Statistical iterative reconstruction in Cone-beam computed tomography (CBCT) uses prior knowledge to form different kinds of regularization terms. The total variation (TV) regularization has shown state-of-the-art performance in suppressing noises and preserving edges. However, it produces the well-known staircase effect. In this paper, a method that involves second-order differential operators was employed to avoid the staircase effect. The ability to avoid staircase effect lies in that higher-order derivatives can avoid over-sharpening the regions of smooth intensity transitions. Meanwhile, a fast iterative shrinkage-thresholding algorithm was used for the corresponding optimization problem. The proposed Hessian Schatten norm-based regularization keeps lots of favorable properties of TV, such as translation and scale invariant, with getting rid of the staircase effect that appears in TV-based reconstructions. The experiments demonstrated the outstanding ability of the proposed algorithm over TV method especially in suppressing the staircase effect.

  16. Fast algorithm of 3D median filter for medical image despeckling

    NASA Astrophysics Data System (ADS)

    Xiong, Chengyi; Hou, Jianhua; Gao, Zhirong; He, Xiang; Chen, Shaoping

    2007-12-01

    Three-dimensional (3-D) median filtering is very useful to eliminate speckle noise from a medical imaging source, such as functional magnetic resonance imaging (fMRI) and ultrasonic imaging. 3-D median filtering is characterized by its higher computation complexity. N 3(N 3-1)/2 comparison operations would be required for 3-D median filtering with N×N×N window if the conventional bubble-sorting algorithm is adopted. In this paper, an efficient fast algorithm for 3-D median filtering was presented, which considerably reduced the computation complexity for extracting the median of a 3-D data array. Compared to the state-of-the-art, the proposed method could reduce the computation complexity of 3-D median filtering by 33%. It results in efficiently reducing the system delay of the 3-D median filter by software implementation, and the system cost and power consumption by hardware implementation.

  17. Robust multiple cue fusion-based high-speed and nonrigid object tracking algorithm for short track speed skating

    NASA Astrophysics Data System (ADS)

    Liu, Chenguang; Cheng, Heng-Da; Zhang, Yingtao; Wang, Yuxuan; Xian, Min

    2016-01-01

    This paper presents a methodology for tracking multiple skaters in short track speed skating competitions. Nonrigid skaters move at high speed with severe occlusions happening frequently among them. The camera is panned quickly in order to capture the skaters in a large and dynamic scene. To automatically track the skaters and precisely output their trajectories becomes a challenging task in object tracking. We employ the global rink information to compensate camera motion and obtain the global spatial information of skaters, utilize random forest to fuse multiple cues and predict the blob of each skater, and finally apply a silhouette- and edge-based template-matching and blob-evolving method to labelling pixels to a skater. The effectiveness and robustness of the proposed method are verified through thorough experiments.

  18. Benchmarking framework for myocardial tracking and deformation algorithms: an open access database.

    PubMed

    Tobon-Gomez, C; De Craene, M; McLeod, K; Tautz, L; Shi, W; Hennemuth, A; Prakosa, A; Wang, H; Carr-White, G; Kapetanakis, S; Lutz, A; Rasche, V; Schaeffter, T; Butakoff, C; Friman, O; Mansi, T; Sermesant, M; Zhuang, X; Ourselin, S; Peitgen, H-O; Pennec, X; Razavi, R; Rueckert, D; Frangi, A F; Rhode, K S

    2013-08-01

    In this paper we present a benchmarking framework for the validation of cardiac motion analysis algorithms. The reported methods are the response to an open challenge that was issued to the medical imaging community through a MICCAI workshop. The database included magnetic resonance (MR) and 3D ultrasound (3DUS) datasets from a dynamic phantom and 15 healthy volunteers. Participants processed 3D tagged MR datasets (3DTAG), cine steady state free precession MR datasets (SSFP) and 3DUS datasets, amounting to 1158 image volumes. Ground-truth for motion tracking was based on 12 landmarks (4 walls at 3 ventricular levels). They were manually tracked by two observers in the 3DTAG data over the whole cardiac cycle, using an in-house application with 4D visualization capabilities. The median of the inter-observer variability was computed for the phantom dataset (0.77 mm) and for the volunteer datasets (0.84 mm). The ground-truth was registered to 3DUS coordinates using a point based similarity transform. Four institutions responded to the challenge by providing motion estimates for the data: Fraunhofer MEVIS (MEVIS), Bremen, Germany; Imperial College London - University College London (IUCL), UK; Universitat Pompeu Fabra (UPF), Barcelona, Spain; Inria-Asclepios project (INRIA), France. Details on the implementation and evaluation of the four methodologies are presented in this manuscript. The manually tracked landmarks were used to evaluate tracking accuracy of all methodologies. For 3DTAG, median values were computed over all time frames for the phantom dataset (MEVIS=1.20mm, IUCL=0.73 mm, UPF=1.10mm, INRIA=1.09 mm) and for the volunteer datasets (MEVIS=1.33 mm, IUCL=1.52 mm, UPF=1.09 mm, INRIA=1.32 mm). For 3DUS, median values were computed at end diastole and end systole for the phantom dataset (MEVIS=4.40 mm, UPF=3.48 mm, INRIA=4.78 mm) and for the volunteer datasets (MEVIS=3.51 mm, UPF=3.71 mm, INRIA=4.07 mm). For SSFP, median values were computed at end diastole and

  19. A fast two-step algorithm for invasion percolation with trapping

    NASA Astrophysics Data System (ADS)

    Masson, Yder

    2016-05-01

    I present a fast algorithm for modeling invasion percolation (IP) with trapping (TIP). IP is a numerical algorithm that models quasi-static (i.e. slow) fluid invasion in porous media. Trapping occurs when the invading fluid (that is injected) forms continuous surfaces surrounding patches of the displaced fluid (that is assumed incompressible and originally saturates the invaded medium). In TIP, the invading fluid is not allowed to enter the trapped patches. I demonstrate that TIP can be modeled in two steps: (1) Run an IP simulation without trapping (NTIP). (2) Identify the sites that invaded trapped regions and remove them from the chronological list of sites invaded in NTIP. Fast algorithms exist for solving NTIP. The focus of this paper is to propose an efficient solution for step (2). I show that it can be solved using a disjoint set data structure and going backward in time, i.e. by un-invading all sites invaded in NTIP in reverse order. Time reversal of the invasion greatly reduces the computational complexity for the identification of trapped sites as one only needs to investigate sites neighbor to the latest invaded/un-invaded site. This differs from traditional approaches where trapping is performed in real time, i.e. as the IP simulation is running, and where it is sometimes necessary to investigate the whole lattice to identify newly trapped regions. With the proposed algorithm, the total computational time for the identification and the removal of trapped sites goes as O(N), where N is the total number of sites in the lattice.

  20. Fast parallel algorithms and enumeration techniques for partial k-trees

    SciTech Connect

    Narayanan, C.

    1989-01-01

    Recent research by several authors have resulted in systematic way of developing linear-time sequential algorithms for a host of problem: on a fairly general class of graphs variously known as bounded decomposable graphs, graphs of bounded treewidth, partial k-trees, etc. Partial k-trees arise in a variety of real-life applications such as network reliability, VLSI design and database systems and hence fast sequential algorithms on these graphs have been found to be desirable. The linear-time methodologies were independently developed by Bern, Lawler, and Wong ((10)), Arnborg and Proskurowski ((6)), Bodlaender ((14)), and Courcelle ((25)). Wimer ((89)) significantly extended the work of Bern, Lawler and Wong. All of these approaches share the common thread of using dynamic programming on a tree structure. In particular the methodology of Wimer uses a parse-tree as the data structure. The methodologies claim linear-time algorithms on partial k-trees for fixed k, for a number of combinatorial optimization problems given the tree structure as input. It is known that obtaining the tree structure is NP-hard. This dissertation investigates three important classes of problems: (1) Developing parallel algorithms for constructing a k-tree embedding, finding a tree decomposition and most notably obtaining a parse-tree for a partial k-tree. (2) Developing parallel algorithms for parse-tree computations, testing isomorphism of k-trees, and finding a 2-tree embedding of a cactus. (3) Obtaining techniques for counting vertex/edge subsets satisfying a certain property in some classes of partial k-trees. The parallel algorithms the author has developed are in class NC and are either new or improve upon the existing results of Bodlaender (13). The difference equations he has obtained for counting certain sub-graphs are not known in the literature so far.

  1. Adaptation of a Fast Optimal Interpolation Algorithm to the Mapping of Oceangraphic Data

    NASA Technical Reports Server (NTRS)

    Menemenlis, Dimitris; Fieguth, Paul; Wunsch, Carl; Willsky, Alan

    1997-01-01

    A fast, recently developed, multiscale optimal interpolation algorithm has been adapted to the mapping of hydrographic and other oceanographic data. This algorithm produces solution and error estimates which are consistent with those obtained from exact least squares methods, but at a small fraction of the computational cost. Problems whose solution would be completely impractical using exact least squares, that is, problems with tens or hundreds of thousands of measurements and estimation grid points, can easily be solved on a small workstation using the multiscale algorithm. In contrast to methods previously proposed for solving large least squares problems, our approach provides estimation error statistics while permitting long-range correlations, using all measurements, and permitting arbitrary measurement locations. The multiscale algorithm itself, published elsewhere, is not the focus of this paper. However, the algorithm requires statistical models having a very particular multiscale structure; it is the development of a class of multiscale statistical models, appropriate for oceanographic mapping problems, with which we concern ourselves in this paper. The approach is illustrated by mapping temperature in the northeastern Pacific. The number of hydrographic stations is kept deliberately small to show that multiscale and exact least squares results are comparable. A portion of the data were not used in the analysis; these data serve to test the multiscale estimates. A major advantage of the present approach is the ability to repeat the estimation procedure a large number of times for sensitivity studies, parameter estimation, and model testing. We have made available by anonymous Ftp a set of MATLAB-callable routines which implement the multiscale algorithm and the statistical models developed in this paper.

  2. Parallelization of an Adaptive Multigrid Algorithm for Fast Solution of Finite Element Structural Problems

    SciTech Connect

    Crane, N K; Parsons, I D; Hjelmstad, K D

    2002-03-21

    Adaptive mesh refinement selectively subdivides the elements of a coarse user supplied mesh to produce a fine mesh with reduced discretization error. Effective use of adaptive mesh refinement coupled with an a posteriori error estimator can produce a mesh that solves a problem to a given discretization error using far fewer elements than uniform refinement. A geometric multigrid solver uses increasingly finer discretizations of the same geometry to produce a very fast and numerically scalable solution to a set of linear equations. Adaptive mesh refinement is a natural method for creating the different meshes required by the multigrid solver. This paper describes the implementation of a scalable adaptive multigrid method on a distributed memory parallel computer. Results are presented that demonstrate the parallel performance of the methodology by solving a linear elastic rocket fuel deformation problem on an SGI Origin 3000. Two challenges must be met when implementing adaptive multigrid algorithms on massively parallel computing platforms. First, although the fine mesh for which the solution is desired may be large and scaled to the number of processors, the multigrid algorithm must also operate on much smaller fixed-size data sets on the coarse levels. Second, the mesh must be repartitioned as it is adapted to maintain good load balancing. In an adaptive multigrid algorithm, separate mesh levels may require separate partitioning, further complicating the load balance problem. This paper shows that, when the proper optimizations are made, parallel adaptive multigrid algorithms perform well on machines with several hundreds of processors.

  3. A Fast Cluster Motif Finding Algorithm for ChIP-Seq Data Sets.

    PubMed

    Zhang, Yipu; Wang, Ping

    2015-01-01

    New high-throughput technique ChIP-seq, coupling chromatin immunoprecipitation experiment with high-throughput sequencing technologies, has extended the identification of binding locations of a transcription factor to the genome-wide regions. However, the most existing motif discovery algorithms are time-consuming and limited to identify binding motifs in ChIP-seq data which normally has the significant characteristics of large scale data. In order to improve the efficiency, we propose a fast cluster motif finding algorithm, named as FCmotif, to identify the (l,  d) motifs in large scale ChIP-seq data set. It is inspired by the emerging substrings mining strategy to find the enriched substrings and then searching the neighborhood instances to construct PWM and cluster motifs in different length. FCmotif is not following the OOPS model constraint and can find long motifs. The effectiveness of proposed algorithm has been proved by experiments on the ChIP-seq data sets from mouse ES cells. The whole detection of the real binding motifs and processing of the full size data of several megabytes finished in a few minutes. The experimental results show that FCmotif has advantageous to deal with the (l,  d) motif finding in the ChIP-seq data; meanwhile it also demonstrates better performance than other current widely-used algorithms such as MEME, Weeder, ChIPMunk, and DREME. PMID:26236718

  4. Combined algorithmic and GPU acceleration for ultra-fast circular conebeam backprojection

    NASA Astrophysics Data System (ADS)

    Brokish, Jeffrey; Sack, Paul; Bresler, Yoram

    2010-04-01

    In this paper, we describe the first implementation and performance of a fast O(N3logN) hierarchical backprojection algorithm for cone beam CT with a circular trajectory1,developed on a modern Graphics Processing Unit (GPU). The resulting tomographic backprojection system for 3D cone beam geometry combines speedup through algorithmic improvements provided by the hierarchical backprojection algorithm with speedup from a massively parallel hardware accelerator. For data parameters typical in diagnostic CT and using a mid-range GPU card, we report reconstruction speeds of up to 360 frames per second, and relative speedup of almost 6x compared to conventional backprojection on the same hardware. The significance of these results is twofold. First, they demonstrate that the reduction in operation counts demonstrated previously for the FHBP algorithm can be translated to a comparable run-time improvement in a massively parallel hardware implementation, while preserving stringent diagnostic image quality. Second, the dramatic speedup and throughput numbers achieved indicate the feasibility of systems based on this technology, which achieve real-time 3D reconstruction for state-of-the art diagnostic CT scanners with small footprint, high-reliability, and affordable cost.

  5. A Fast Hyperplane-Based Minimum-Volume Enclosing Simplex Algorithm for Blind Hyperspectral Unmixing

    NASA Astrophysics Data System (ADS)

    Lin, Chia-Hsiang; Chi, Chong-Yung; Wang, Yu-Hsiang; Chan, Tsung-Han

    2016-04-01

    Hyperspectral unmixing (HU) is a crucial signal processing procedure to identify the underlying materials (or endmembers) and their corresponding proportions (or abundances) from an observed hyperspectral scene. A well-known blind HU criterion, advocated by Craig in early 1990's, considers the vertices of the minimum-volume enclosing simplex of the data cloud as good endmember estimates, and it has been empirically and theoretically found effective even in the scenario of no pure pixels. However, such kind of algorithms may suffer from heavy simplex volume computations in numerical optimization, etc. In this work, without involving any simplex volume computations, by exploiting a convex geometry fact that a simplest simplex of N vertices can be defined by N associated hyperplanes, we propose a fast blind HU algorithm, for which each of the N hyperplanes associated with the Craig's simplex of N vertices is constructed from N-1 affinely independent data pixels, together with an endmember identifiability analysis for its performance support. Without resorting to numerical optimization, the devised algorithm searches for the N(N-1) active data pixels via simple linear algebraic computations, accounting for its computational efficiency. Monte Carlo simulations and real data experiments are provided to demonstrate its superior efficacy over some benchmark Craig-criterion-based algorithms in both computational efficiency and estimation accuracy.

  6. Impact of a Fast-Track Esophagectomy Protocol on Esophageal Cancer Patient Outcomes and Hospital Charges

    PubMed Central

    Shewale, Jitesh B.; Correa, Arlene M.; Baker, Carla M.; Villafane-Ferriol, Nicole; Hofstetter, Wayne L.; Jordan, Victoria S.; Kehlet, Henrik; Lewis, Katie M.; Mehran, Reza J.; Summers, Barbara L.; Schaub, Diane; Wilks, Sonia A.; Swisher, Stephen G.

    2016-01-01

    Objective To evaluate the effects of a fast-track esophagectomy protocol (FTEP) on esophageal cancer patients' safety, length of hospital stay (LOS) and hospital charges. Background FTEP involved transferring patients to the telemetry unit instead of the surgical intensive care unit (SICU) after esophagectomy. Methods We retrospectively reviewed 708 consecutive patients who underwent esophagectomy for primary esophageal cancer during the 4 years before (group A; 322 patients) or 4 years after (group B; 386 patients) the institution of an FTEP. Postoperative morbidity and mortality, LOS, and hospital charges were reviewed. Results Compared with group A, group B had significantly shorter median LOS (12 days vs 8 days; P < 0.001); lower mean numbers of SICU days (4.5 days vs 1.2 days; P < 0.001) and telemetry days (12.7 days vs 9.7 days; P < 0.001); and lower rates of atrial arrhythmia (27% vs 19%; P = 0.013) and pulmonary complications (27% vs 20%; P = 0.016). Multivariable analysis revealed FTEP to be associated with shorter LOS (P < 0.001) even after adjustment for predictors like tumor histology and location. FTEP was also associated with a lower rate of pulmonary complications (odds ratio = 0.655; 95% confidence interval = 0.456, 0.942; P = 0.022). In addition, the median hospital charges associated with primary admission and readmission within 90 days for group B ($65,649) were lower than that for group A ($79,117; P < 0.001). Conclusion These findings suggest that an FTEP reduces patients' LOS, perioperative morbidity and hospital charges. PMID:25243545

  7. Traditional healers and the "Fast-Track" HIV response: is success possible without them?

    PubMed

    Leclerc-Madlala, Suzanne; Green, Edward; Hallin, Mary

    2016-07-01

    The rapid scale-up of effective HIV prevention strategies is a central theme of the post-2015 health and development agenda. All major global HIV and AIDS funders have aligned their policies and plans to achieve sharp reductions in new HIV infections and reach epidemic control by 2030. In these "fast-track" plans, increased antiretroviral treatment coverage and the attainment of viral suppression are pivotal, and there is firm recognition of the need for countries to mobilise more domestic resources and build stronger community clinic systems. There is little in these bold plans, however, to suggest that the now 30-year-old call by the World Health Organization (WHO) and other organisations to establish systematic collaborations with the traditional health sector will finally be heeded. In the context of sub-Saharan Africa's HIV epidemic, a significant body of literature demonstrates the critical role that traditional healers can play in improving the success of health programmes, including those for HIV prevention. This paper provides a brief history of collaboration with traditional healers for HIV followed by a description of several successful collaborations and discussion of key elements for success. We argue that the traditional health sector is a major resource that has yet to be sufficiently mobilised against HIV. As we shift from a short-term HIV response to a longer-term and more sustainable response, there is an urgent need to accelerate efforts to leverage and partner with the hundreds of thousands of traditional health practitioners who are already providing health services in communities. Failure to better attune our work to the medical pluralism of communities affected by HIV will continue to hinder HIV programming success and help assure that ambitious post-2015 HIV prevention and control goals are not realised. PMID:27399048

  8. Real-time tracking and fast retrieval of persons in multiple surveillance cameras of a shopping mall

    NASA Astrophysics Data System (ADS)

    Bouma, Henri; Baan, Jan; Landsmeer, Sander; Kruszynski, Chris; van Antwerpen, Gert; Dijk, Judith

    2013-05-01

    The capability to track individuals in CCTV cameras is important for e.g. surveillance applications at large areas such as train stations, airports and shopping centers. However, it is laborious to track and trace people over multiple cameras. In this paper, we present a system for real-time tracking and fast interactive retrieval of persons in video streams from multiple static surveillance cameras. This system is demonstrated in a shopping mall, where the cameras are positioned without overlapping fields-of-view and have different lighting conditions. The results show that the system allows an operator to find the origin or destination of a person more efficiently. The misses are reduced with 37%, which is a significant improvement.

  9. A reduced-complexity data-fusion algorithm using belief propagation for location tracking in heterogeneous observations.

    PubMed

    Chiou, Yih-Shyh; Tsai, Fuan

    2014-06-01

    This paper presents a low-complexity and high-accuracy algorithm to reduce the computational load of the traditional data-fusion algorithm with heterogeneous observations for location tracking. For the location-estimation technique with the data fusion of radio-based ranging measurement and speed-based sensing measurement, the proposed tracking scheme, based on the Bayesian filtering concept, is handled by a state space model. The location tracking problem is divided into many mutual-interaction local constraints with the inherent message- passing features of factor graphs. During each iteration cycle, the messages with reliable information are passed efficiently between the prediction phase and the correction phase to simplify the data-fusion implementation for tracking the location of the mobile terminal. Numerical simulations show that the proposed forward and one-step backward refining tracking approach that combines radio ranging with speed sensing measurements for data fusion not only can achieve an accurate location close to that of the traditional Kalman filtering data-fusion algorithm, but also has much lower computational complexity. PMID:24013831

  10. The Implementation of the Fast Track Program: An Example of a Large-Scale Prevention Science Efficacy Trial

    PubMed Central

    2009-01-01

    In 1990, the Fast Track Project was initiated to evaluate the feasibility and effectiveness of a comprehensive, multicomponent prevention program targeting children at risk for conduct disorders in four demographically diverse American communities (Conduct Problems Prevention Research Group [CPPRG], 1992). Representing a prevention science approach toward community-based preventive intervention, the Fast Track intervention design was based upon the available data base elucidating the epidemiology of risk for conduct disorder and suggesting key causal developmental influences (R. P. Weissberg & M. T. Greenberg, 1998). Critical questions about this approach to prevention center around the extent to which such a science-based program can be effective at (1) engaging community members and stakeholders, (2) maintaining intervention fidelity while responding appropriately to the local norms and needs of communities that vary widely in their demographic and cultural/ethnic composition, and (3) maintaining community engagement in the long-term to support effective and sustainable intervention dissemination. This paper discusses these issues, providing examples from the Fast Track project to illustrate the process of program implementation and the evidence available regarding the success of this science-based program at engaging communities in sustainable and effective ways as partners in prevention programming. PMID:11930968

  11. Role of preoperative pain, muscle function, and activity level in discharge readiness after fast-track hip and knee arthroplasty

    PubMed Central

    Holm, Bente; Bandholm, Thomas; Lunn, Troels Haxholdt; Husted, Henrik; Aalund, Peter Kloster; Hansen, Torben Bæk

    2014-01-01

    Background and purpose The concept of fast-track surgery has led to a decline in length of stay after total hip arthroplasty (THA) and total knee arthroplasty (TKA) to about 2–4 days. However, it has been questioned whether this is only achievable in selected patients—or in all patients. We therefore investigated the role of preoperative pain and functional characteristics in discharge readiness and actual LOS in fast-track THA and TKA. Methods Before surgery, hip pain (THA) or knee pain (TKA), lower-extremity muscle power, functional performance, and physical activity were assessed in a sample of 150 patients and used as independent variables to predict the outcome (dependent variable)—readiness for hospital discharge —for each type of surgery. Discharge readiness was assessed twice daily by blinded assessors. Results Median discharge readiness and actual length of stay until discharge were both 2 days. Univariate linear regression followed by multiple linear regression revealed that age was the only independent predictor of discharge readiness in THA and TKA, but the standardized coefficients were small (≤ 0.03). Interpretation These results support the idea that fast-track THA and TKA with a length of stay of about 2–4 days can be achieved for most patients independently of preoperative functional characteristics. PMID:24954491

  12. Improved relocatable over-the-horizon radar detection and tracking using the maximum likelihood adaptive neural system algorithm

    NASA Astrophysics Data System (ADS)

    Perlovsky, Leonid I.; Webb, Virgil H.; Bradley, Scott R.; Hansen, Christopher A.

    1998-07-01

    An advanced detection and tracking system is being developed for the U.S. Navy's Relocatable Over-the-Horizon Radar (ROTHR) to provide improved tracking performance against small aircraft typically used in drug-smuggling activities. The development is based on the Maximum Likelihood Adaptive Neural System (MLANS), a model-based neural network that combines advantages of neural network and model-based algorithmic approaches. The objective of the MLANS tracker development effort is to address user requirements for increased detection and tracking capability in clutter and improved track position, heading, and speed accuracy. The MLANS tracker is expected to outperform other approaches to detection and tracking for the following reasons. It incorporates adaptive internal models of target return signals, target tracks and maneuvers, and clutter signals, which leads to concurrent clutter suppression, detection, and tracking (track-before-detect). It is not combinatorial and thus does not require any thresholding or peak picking and can track in low signal-to-noise conditions. It incorporates superresolution spectrum estimation techniques exceeding the performance of conventional maximum likelihood and maximum entropy methods. The unique spectrum estimation method is based on the Einsteinian interpretation of the ROTHR received energy spectrum as a probability density of signal frequency. The MLANS neural architecture and learning mechanism are founded on spectrum models and maximization of the "Einsteinian" likelihood, allowing knowledge of the physical behavior of both targets and clutter to be injected into the tracker algorithms. The paper describes the addressed requirements and expected improvements, theoretical foundations, engineering methodology, and results of the development effort to date.

  13. Improvements in fast-response flood modeling: desktop parallel computing and domain tracking

    SciTech Connect

    Judi, David R; Mcpherson, Timothy N; Burian, Steven J

    2009-01-01

    It is becoming increasingly important to have the ability to accurately forecast flooding, as flooding accounts for the most losses due to natural disasters in the world and the United States. Flood inundation modeling has been dominated by one-dimensional approaches. These models are computationally efficient and are considered by many engineers to produce reasonably accurate water surface profiles. However, because the profiles estimated in these models must be superimposed on digital elevation data to create a two-dimensional map, the result may be sensitive to the ability of the elevation data to capture relevant features (e.g. dikes/levees, roads, walls, etc...). Moreover, one-dimensional models do not explicitly represent the complex flow processes present in floodplains and urban environments and because two-dimensional models based on the shallow water equations have significantly greater ability to determine flow velocity and direction, the National Research Council (NRC) has recommended that two-dimensional models be used over one-dimensional models for flood inundation studies. This paper has shown that two-dimensional flood modeling computational time can be greatly reduced through the use of Java multithreading on multi-core computers which effectively provides a means for parallel computing on a desktop computer. In addition, this paper has shown that when desktop parallel computing is coupled with a domain tracking algorithm, significant computation time can be eliminated when computations are completed only on inundated cells. The drastic reduction in computational time shown here enhances the ability of two-dimensional flood inundation models to be used as a near-real time flood forecasting tool, engineering, design tool, or planning tool. Perhaps even of greater significance, the reduction in computation time makes the incorporation of risk and uncertainty/ensemble forecasting more feasible for flood inundation modeling (NRC 2000; Sayers et al

  14. A comparative study on the contour tracking algorithms in ultrasound tongue images with automatic re-initialization.

    PubMed

    Xu, Kele; Gábor Csapó, Tamás; Roussel, Pierre; Denby, Bruce

    2016-05-01

    The feasibility of an automatic re-initialization of contour tracking is explored by using an image similarity-based method in the ultrasound tongue sequences. To this end, the re-initialization method was incorporated into current state-of-art tongue tracking algorithms, and a quantitative comparison was made between different algorithms by computing the mean sum of distances errors. The results demonstrate that with automatic re-initialization, the tracking error can be reduced from an average of 5-6 to about 4 pixels, a result obtained by using a large number of hand-labeled frames and similarity measurements to extract the contours, which results in improved performance. PMID:27250201

  15. A Novel Square-Root Cubature Information Weighted Consensus Filter Algorithm for Multi-Target Tracking in Distributed Camera Networks

    PubMed Central

    Chen, Yanming; Zhao, Qingjie

    2015-01-01

    This paper deals with the problem of multi-target tracking in a distributed camera network using the square-root cubature information filter (SCIF). SCIF is an efficient and robust nonlinear filter for multi-sensor data fusion. In camera networks, multiple cameras are arranged in a dispersed manner to cover a large area, and the target may appear in the blind area due to the limited field of view (FOV). Besides, each camera might receive noisy measurements. To overcome these problems, this paper proposes a novel multi-target square-root cubature information weighted consensus filter (MTSCF), which reduces the effect of clutter or spurious measurements using joint probabilistic data association (JPDA) and proper weights on the information matrix and information vector. The simulation results show that the proposed algorithm can efficiently track multiple targets in camera networks and is obviously better in terms of accuracy and stability than conventional multi-target tracking algorithms. PMID:25951338

  16. A novel square-root cubature information weighted consensus filter algorithm for multi-target tracking in distributed camera networks.

    PubMed

    Chen, Yanming; Zhao, Qingjie

    2015-01-01

    This paper deals with the problem of multi-target tracking in a distributed camera network using the square-root cubature information filter (SCIF). SCIF is an efficient and robust nonlinear filter for multi-sensor data fusion. In camera networks, multiple cameras are arranged in a dispersed manner to cover a large area, and the target may appear in the blind area due to the limited field of view (FOV). Besides, each camera might receive noisy measurements. To overcome these problems, this paper proposes a novel multi-target square-root cubature information weighted consensus filter (MTSCF), which reduces the effect of clutter or spurious measurements using joint probabilistic data association (JPDA) and proper weights on the information matrix and information vector. The simulation results show that the proposed algorithm can efficiently track multiple targets in camera networks and is obviously better in terms of accuracy and stability than conventional multi-target tracking algorithms. PMID:25951338

  17. Vibration extraction based on fast NCC algorithm and high-speed camera.

    PubMed

    Lei, Xiujun; Jin, Yi; Guo, Jie; Zhu, Chang'an

    2015-09-20

    In this study, a high-speed camera system is developed to complete the vibration measurement in real time and to overcome the mass introduced by conventional contact measurements. The proposed system consists of a notebook computer and a high-speed camera which can capture the images as many as 1000 frames per second. In order to process the captured images in the computer, the normalized cross-correlation (NCC) template tracking algorithm with subpixel accuracy is introduced. Additionally, a modified local search algorithm based on the NCC is proposed to reduce the computation time and to increase efficiency significantly. The modified algorithm can rapidly accomplish one displacement extraction 10 times faster than the traditional template matching without installing any target panel onto the structures. Two experiments were carried out under laboratory and outdoor conditions to validate the accuracy and efficiency of the system performance in practice. The results demonstrated the high accuracy and efficiency of the camera system in extracting vibrating signals. PMID:26406525

  18. Applying the uniform resampling (URS) algorithm to a lissajous trajectory: fast image reconstruction with optimal gridding.

    PubMed

    Moriguchi, H; Wendt, M; Duerk, J L

    2000-11-01

    Various kinds of nonrectilinear Cartesian k-space trajectories have been studied, such as spiral, circular, and rosette trajectories. Although the nonrectilinear Cartesian sampling techniques generally have the advantage of fast data acquisition, the gridding process prior to 2D-FFT image reconstruction usually requires a number of additional calculations, thus necessitating an increase in the computation time. Further, the reconstructed image often exhibits artifacts resulting from both the k-space sampling pattern and the gridding procedure. To date, it has been demonstrated in only a few studies that the special geometric sampling patterns of certain specific trajectories facilitate fast image reconstruction. In other words, the inherent link among the trajectory, the sampling scheme, and the associated complexity of the regridding/reconstruction process has been investigated to only a limited extent. In this study, it is demonstrated that a Lissajous trajectory has the special geometric characteristics necessary for rapid reconstruction of nonrectilinear Cartesian k-space trajectories with constant sampling time intervals. Because of the applicability of a uniform resampling (URS) algorithm, a high-quality reconstructed image is obtained in a short reconstruction time when compared to other gridding algorithms. PMID:11064412

  19. Application of least mean square algorithm to suppression of maglev track-induced self-excited vibration

    NASA Astrophysics Data System (ADS)

    Zhou, D. F.; Li, J.; Hansen, C. H.

    2011-11-01

    Track-induced self-excited vibration is commonly encountered in EMS (electromagnetic suspension) maglev systems, and a solution to this problem is important in enabling the commercial widespread implementation of maglev systems. Here, the coupled model of the steel track and the magnetic levitation system is developed, and its stability is investigated using the Nyquist criterion. The harmonic balance method is employed to investigate the stability and amplitude of the self-excited vibration, which provides an explanation of the phenomenon that track-induced self-excited vibration generally occurs at a specified amplitude and frequency. To eliminate the self-excited vibration, an improved LMS (Least Mean Square) cancellation algorithm with phase correction (C-LMS) is employed. The harmonic balance analysis shows that the C-LMS cancellation algorithm can completely suppress the self-excited vibration. To achieve adaptive cancellation, a frequency estimator similar to the tuner of a TV receiver is employed to provide the C-LMS algorithm with a roughly estimated reference frequency. Numerical simulation and experiments undertaken on the CMS-04 vehicle show that the proposed adaptive C-LMS algorithm can effectively eliminate the self-excited vibration over a wide frequency range, and that the robustness of the algorithm suggests excellent potential for application to EMS maglev systems.

  20. Quantitative measurement of Parkinsonian gait from walking in monocular image sequences using a centroid tracking algorithm.

    PubMed

    Lin, Sheng-Huang; Chen, Shih-Wei; Lo, Yu-Chun; Lai, Hsin-Yi; Yang, Chich-Haung; Chen, Shin-Yuan; Chang, Yuan-Jen; Chen, Chin-Hsing; Huang, Wen-Tzeng; Jaw, Fu-Shan; Chen, You-Yin; Tsang, Siny; Liao, Lun-De

    2016-03-01

    Parkinson's disease (PD) is a neurodegenerative disease of the central nervous system that results from the degeneration of dopaminergic neurons in the substantia nigra. Abnormal gait begins in the early stage and becomes severe as the disease progresses; therefore, the assessment of gait becomes an important issue in evaluating the progression of PD and the effectiveness of treatment. To provide a clinically useful gait assessment in environments with budget and space limitations, such as a small clinic or home, we propose and develop a portable method utilizing the monocular image sequences of walking to track and analyze a Parkinsonian gait pattern. In addition, a centroid tracking algorithm is developed and used here to enhance the method of quantifying kinematic gait parameters of PD in different states. Twelve healthy subjects and twelve mild patients with PD participate in this study. This method requires one digital video camera and subjects with two joint markers attached on the fibula head and the lateral malleolus of the leg. All subjects walk with a natural pace in front of a video camera during the trials. Results of our study demonstrate the stride length and walking velocity significantly decrease in PD without drug compared to PD with drug in both proposed method and simultaneous gait assessment performed by GAITRite(®) system. In gait initiation, step length and swing velocity also decrease in PD without drug compared to both PD with drug and controls. Our results showed high correlation in gait parameters between the two methods and prove the reliability of the proposed method. With the proposed method, quantitative measurement and analysis of Parkinsonian gait could be inexpensive to implement, portable within a small clinic or home, easy to administer, and simple to interpret. Although this study is assessed Parkinsonian gait, the proposed method has the potential to help clinicians and researchers assess the gait of patients with other