WorldWideScience

Sample records for asynchronous particle tracking

  1. 3D asynchronous particle tracking in single and dual continuum matrix-fractures. Application to nuclear waste storage; Modelisation 3D du transport particulaire asynchrone en simple et double continuum matrice-fractures: application au stockage de dechets nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Lam, M.Ph

    2008-06-15

    This PhD research was conducted as a collaboration between Laboratoire National d'Hydraulique et Environnement (LNHE) from EDF R and D and the Institut de Mecanique des Fluides de Toulouse (IMFT) in the frame of a CIFRE contract. This PhD thesis aims at providing LNHE a reliable numerical model to study the feasibility of a nuclear waste storage in deep geological structures. The main focus of the thesis is put on developing and implementing a Random Walk Particle Method (RWPM) to model contaminant transport in 3D heterogeneous and fractured porous media. In its first part, the report presents the Lagrangian particle tracking method used to model transport in heterogeneous media with a direct high resolution approach. The solute plume is discretized into concentration packets: particles. The model tracks each particle based on a time-explicit displacement algorithm according to an advective component and a diffusive random component. The method is implemented on a hydraulic model discretized on a 3D unstructured tetrahedral finite element mesh. We focus on techniques to overcome problems due to the discontinuous transport parameters and the unstructured mesh. First, we introduce an asynchronous time-stepping approach to deal with the numerical and overshoot errors that occur with conventional RWPM. Then, a filtering method is applied to smooth discontinuous transport parameters (pre-processing). Finally, once the particle displacements are computed, we propose several filtering and sampling methods to obtain concentrations from particle positions (post-processing). Applications of these methods are presented with cases of tracer advection-dispersion in homogeneous and heterogeneous media. For dense fracture networks, direct high resolution methods are very time consuming and need a lot of computational resources. So, as an alternative to the discrete approach, a dual-continuum representation is used, in the second part of the report, to describe the porous

  2. Selective particle capture by asynchronously beating cilia

    Science.gov (United States)

    Ding, Yang; Kanso, Eva

    2015-12-01

    Selective particle filtration is fundamental in many engineering and biological systems. For example, many aquatic microorganisms use filter feeding to capture food particles from the surrounding fluid, using motile cilia. One of the capture strategies is to use the same cilia to generate feeding currents and to intercept particles when the particles are on the downstream side of the cilia. Here, we develop a 3D computational model of ciliary bands interacting with flow suspended particles and calculate particle trajectories for a range of particle sizes. Consistent with experimental observations, we find optimal particle sizes that maximize capture rate. The optimal size depends nonlinearly on cilia spacing and cilia coordination, synchronous vs. asynchronous. These parameters affect the cilia-generated flow field, which in turn affects particle trajectories. The low capture rate of smaller particles is due to the particles' inability to cross the flow streamlines of neighboring cilia. Meanwhile, large particles have difficulty entering the sub-ciliary region once advected downstream, also resulting in low capture rates. The optimal range of particle sizes is enhanced when cilia beat asynchronously. These findings have potentially important implications on the design and use of biomimetic cilia in processes such as particle sorting in microfluidic devices.

  3. Fuzzy Logic Particle Tracking

    Science.gov (United States)

    2005-01-01

    A new all-electronic Particle Image Velocimetry technique that can efficiently map high speed gas flows has been developed in-house at the NASA Lewis Research Center. Particle Image Velocimetry is an optical technique for measuring the instantaneous two component velocity field across a planar region of a seeded flow field. A pulsed laser light sheet is used to illuminate the seed particles entrained in the flow field at two instances in time. One or more charged coupled device (CCD) cameras can be used to record the instantaneous positions of particles. Using the time between light sheet pulses and determining either the individual particle displacements or the average displacement of particles over a small subregion of the recorded image enables the calculation of the fluid velocity. Fuzzy logic minimizes the required operator intervention in identifying particles and computing velocity. Using two cameras that have the same view of the illumination plane yields two single exposure image frames. Two competing techniques that yield unambiguous velocity vector direction information have been widely used for reducing the single-exposure, multiple image frame data: (1) cross-correlation and (2) particle tracking. Correlation techniques yield averaged velocity estimates over subregions of the flow, whereas particle tracking techniques give individual particle velocity estimates. For the correlation technique, the correlation peak corresponding to the average displacement of particles across the subregion must be identified. Noise on the images and particle dropout result in misidentification of the true correlation peak. The subsequent velocity vector maps contain spurious vectors where the displacement peaks have been improperly identified. Typically these spurious vectors are replaced by a weighted average of the neighboring vectors, thereby decreasing the independence of the measurements. In this work, fuzzy logic techniques are used to determine the true

  4. PARTICLE BEAM TRACKING CIRCUIT

    Science.gov (United States)

    Anderson, O.A.

    1959-05-01

    >A particle-beam tracking and correcting circuit is described. Beam induction electrodes are placed on either side of the beam, and potentials induced by the beam are compared in a voltage comparator or discriminator. This comparison produces an error signal which modifies the fm curve at the voltage applied to the drift tube, thereby returning the orbit to the preferred position. The arrangement serves also to synchronize accelerating frequency and magnetic field growth. (T.R.H.)

  5. A Parallel Particle Swarm Optimization Algorithm Accelerated by Asynchronous Evaluations

    Science.gov (United States)

    Venter, Gerhard; Sobieszczanski-Sobieski, Jaroslaw

    2005-01-01

    A parallel Particle Swarm Optimization (PSO) algorithm is presented. Particle swarm optimization is a fairly recent addition to the family of non-gradient based, probabilistic search algorithms that is based on a simplified social model and is closely tied to swarming theory. Although PSO algorithms present several attractive properties to the designer, they are plagued by high computational cost as measured by elapsed time. One approach to reduce the elapsed time is to make use of coarse-grained parallelization to evaluate the design points. Previous parallel PSO algorithms were mostly implemented in a synchronous manner, where all design points within a design iteration are evaluated before the next iteration is started. This approach leads to poor parallel speedup in cases where a heterogeneous parallel environment is used and/or where the analysis time depends on the design point being analyzed. This paper introduces an asynchronous parallel PSO algorithm that greatly improves the parallel e ciency. The asynchronous algorithm is benchmarked on a cluster assembled of Apple Macintosh G5 desktop computers, using the multi-disciplinary optimization of a typical transport aircraft wing as an example.

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

    Science.gov (United States)

    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

  7. Fuzzy logic particle tracking velocimetry

    Science.gov (United States)

    Wernet, Mark P.

    1993-01-01

    Fuzzy logic has proven to be a simple and robust method for process control. Instead of requiring a complex model of the system, a user defined rule base is used to control the process. In this paper the principles of fuzzy logic control are applied to Particle Tracking Velocimetry (PTV). Two frames of digitally recorded, single exposure particle imagery are used as input. The fuzzy processor uses the local particle displacement information to determine the correct particle tracks. Fuzzy PTV is an improvement over traditional PTV techniques which typically require a sequence (greater than 2) of image frames for accurately tracking particles. The fuzzy processor executes in software on a PC without the use of specialized array or fuzzy logic processors. A pair of sample input images with roughly 300 particle images each, results in more than 200 velocity vectors in under 8 seconds of processing time.

  8. Particle tracking with scintillating fibres

    CERN Document Server

    D'Ambrosio, C; Leutz, H; Puertolas, D

    1996-01-01

    This article presents our R&D-work on particle tracking with scintillating fibres. We have developed new fibre dyes, more efficient fibre cladding, coherent fibre bundles with improved packing fraction and a new fibre readout technique (ISPA-tube). Altogether, these new developments increased the hit density of fine grain (60 µm) fibres by about 7 times. This results in mini-tracks per 2.5 mm fibre layer rather than in single hits only and enhances the track reconstruction efficiency to nearly 100 %. Compared with competing tracking methods (silicon strips, MSGCs), our scintillating fibres are superior in hit numbers per radiation length and in the 2-track resolution. They require much less readout channels and consequently no cooling provisions to remove their electronic heat.

  9. Particle tracking around surface nanobubbles

    CERN Document Server

    Dietrich, Erik; Lohse, Detlef; Seddon, James R T

    2016-01-01

    The exceptionally long lifetime of surface nanobubbles remains one of the biggest questions in the field. One of the proposed mechanisms for the stability is the \\emph{dynamic equilibrium} model, which describes a constant flux of gas in and out of the bubble. Here, we describe results from particle tracking experiments to measure this flow. The results are analysed by measuring the Vorono\\"i cell size distribution, the diffusion, and speed of the tracer particles. We show that there is no detectable difference in the movement of particles above nanobubble-laden surfaces, as compared to nanobubble-free surfaces.

  10. Particle Tracking of Fluorescent Microspheres

    Science.gov (United States)

    Kaminski, Zofia; Mueller, Joachim; Berk, Serkan

    2010-10-01

    In this research, the diffusion coefficients of the fluorescent microspheres and the relation of those coefficients to particle radius were investigated. An additional focus was to see how well the measured radius of the microspheres compared to the radius as reported by the manufacturer and to measure the distribution of radii in a sample. This study further developed the critical process of ensuring particle movement within the sample volume and made preliminary sample measurements.The methods developed for tracking microspheres will later be used to determine the radii of virus like particles (VLPs), which are a non-infectious model system of the HIV virus. Results from our measurements will be reported.

  11. Two-Particle Asynchronous Quantum Correlation: Wavefunction Collapse Acting as a Beamsplitter

    Science.gov (United States)

    Kowalski, F. V.; Browne, R. S.

    2016-03-01

    A two-body quantum correlation is calculated for a particle reflecting from a moving mirror. Correlated interference results when the incident and reflected particle substates and their associated mirror substates overlap. Using the Copenhagen interpretation of measurement, an asynchronous joint probability density (PDF), which is a function both of the different positions and different times at which the particle and mirror are measured, is derived assuming that no interaction occurs between each measurement. Measurement of the particle first, in the correlated interference region, results in a splitting of the mirror substate into ones which have and have not reflected the particle. An analog of the interference from the Doppler effect for only measurements of the particle (a marginal PDF), in this two-body system, is shown to be a consequence of the asynchronous measurement. The simplification obtained for a microscopic particle reflecting from a mesoscopic or macroscopic mirror is used to illustrate asynchronous correlation interferometry. In this case, the small displacement between these mirror states can yield negligible environmental decoherence times. In addition, interference of these mirror states does not vanish in the limit of large mirror mass due to the small momentum exchange in reflecting a microscopic particle.

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

    Science.gov (United States)

    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

  13. Bayesian target tracking based on particle filter

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    For being able to deal with the nonlinear or non-Gaussian problems, particle filters have been studied by many researchers. Based on particle filter, the extended Kalman filter (EKF) proposal function is applied to Bayesian target tracking. Markov chain Monte Carlo (MCMC) method, the resampling step, etc novel techniques are also introduced into Bayesian target tracking. And the simulation results confirm the improved particle filter with these techniques outperforms the basic one.

  14. Better track leads to new particles

    CERN Multimedia

    2006-01-01

    "Dutch researcher Thijs Cornelissen developed an algorithm to reconstruct the particle tracks and that is being used in a European research institute for particle physics. His method provides greater insights into the origine of particles that arise as a result of collisions." (1/2 page)

  15. A Particle Filter of Blind Equalization and Multiuser Detection in Asynchronous DS/CDMA Systems

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing; DONG Jian-ping; ZHANG Qian

    2008-01-01

    The particle filter (PF) is proposed to be the asynchronous direct-sequence eude-division multiple-access (DS/CDMA) multiuser detector without knowing the channel state information. The PF performs symbol detection according to the joint posterior density probability of simulated particles including relative delays, fading gains and symbols via sequential importance sample and resample. A simplified scheme is also proposed by separating the independent relative delays and fading with symbols. These parameters are modeled as the extended aggressive processes and estimated by the Kalman fdter, so as to provide their arbitrary importance distribution for symbol detection. Simulation results show that the bit error rate of the PF is less than convntional detectors.Moreover, the complexity of PF is moderate comaparable to other nonlinear suboptimal approaches.

  16. Particle Filters for Positioning, Navigation and Tracking

    OpenAIRE

    Gustafsson, Fredrik; Gunnarsson, Fredrik; Bergman, Niclas; Forssell, Urban; Jansson, Jonas; Karlsson, Rickard; Nordlund, Per-Johan

    2001-01-01

    A framework for positioning, navigation and tracking problems using particle filters (sequential Monte Carlo methods) is developed. It consists of a class of motion models and a general non-linear measurement equation in position. A general algorithm is presented, which is parsimonious with the particle dimension. It is based on marginalization, enabling a Kalman filter to estimate all position derivatives, and the particle filter becomes low-dimensional. This is of utmost importance for high...

  17. Discovery Mondays - 'Particle tracks: Seeing the invisible'

    CERN Multimedia

    2007-01-01

    Simulation of particle tracks in the CMS detector. How can you 'see' something as infinitesimal and fleeting as an elementary particle that defeats even the most powerful microscope? Well, physicists have detectors to snoop on them. Unlike biologists looking at bacteria, physicists don't see the particles themselves. They study their impact on sensitive materials as they pass through them at ultra high speed, a bit like seeing plane vapour trails in a clear sky. At the next Discovery Monday you will be able to find out about the different methods used at CERN to detect particles. There will be demonstrations of the cloud chamber, where particles leave tell-tale evidence of their passage in tracks of droplets. You will also learn about past and current particle track detection techniques and how the tracks are reconstructed into magnificent composite images. Don't miss this opportunity to learn about the various ways of 'seeing' particles. The event will be conducted in French. Come along to the Microcosm ...

  18. Digital characterization of particle tracks for microdosimetry

    International Nuclear Information System (INIS)

    Work is in progress to develop a digital approach to microdosimetry and to construct a prototype instrument to obtain digital information about charged-particle tracks. The objective of such a device is to measure the numbers of electrons produced in various subvolumes of a chamber gas along a particle's path. This paper describes results of Monte Carlo calculations of charged-particle tracks in a cubical time-projection ionization chamber containing methane. Results are presented to show the effects of electron diffusion during charge collection. The calculations indicate that the optimum ratio of field strength and pressure is about 0.6 volts cm-1 torr-1. Examples of proton, carbon-ion, and electron tracks are shown. 2 refs., 6 figs

  19. Fast particle tracking with wake fields

    Energy Technology Data Exchange (ETDEWEB)

    Dohlus, M.; Floettmann, K.; Henning, C.

    2012-01-15

    Tracking calculations of charged particles in electromagnetic fields require in principle the simultaneous solution of the equation of motion and of Maxwell's equations. In many tracking codes a simpler and more efficient approach is used: external fields like that of the accelerating structures are provided as field maps, generated in separate computations and for the calculation of self fields the model of a particle bunch in uniform motion is used. We describe how an externally computed wake function can be approximated by a table of Taylor coefficients and how the wake field kick can be calculated for the particle distribution in a tracking calculation. The integrated kick, representing the effect of a distributed structure, is applied at a discrete time. As an example, we use our approach to calculate the emittance growth of a bunch in an undulator beam pipe due to resistive wall wake field effects. (orig.)

  20. Dominant Correlogram Based Particle Filter Tracking

    Institute of Scientific and Technical Information of China (English)

    MAO Yan-fen; SHI Peng-fei

    2005-01-01

    A novel dominant correlogram based particle filter was proposed for an object tracking in visual surveillance. Particle filter outperforms the Kalman filter in non-linear and non-Gaussian estimation problem. This paper proposed incorporating spatial information into visual feature, and yields a reliable likelihood description of the observation and prediction. A similarity-ratio is defined to evaluate the effectivity of different similarity measurements in weighing samples. The experimental results demonstrate the effective and robust performance compared with the histogram based tracking in traffic scenes.

  1. Particle Filter for Estimation and Tracking

    Institute of Scientific and Technical Information of China (English)

    Ji-zhen WANG; Zeng-shun ZHAO; Xiao-wei AN; Shu-xia TIAN

    2010-01-01

    In recent years, the particle filter technique has been widely used in tracking, estimation and navigation. In this paper, the authors described several practical filters including the general practical, the extended Kaman practical, and the unscented particle filters. And they explained the degeneracy problem in the practical filter process, and introduced some solved methods. Finally they demonstrated the estimation of different particle filters in non-liner and non-Gaussian situation respectively. The result proved the unscented particle filter had the best performance.

  2. Tracking particles by passing messages between images

    Energy Technology Data Exchange (ETDEWEB)

    Chertkov, Michael [Los Alamos National Laboratory; Kroc, Lukas [Los Alamos National Laboratory; Zdeborova, Lenka [Los Alamos National Laboratory; Krakala, Florent [ESPCI; Vergassola, M [CNRS

    2009-01-01

    Methods to extract information from the tracking of mobile objects/particles have broad interest in biological and physical sciences. Techniques based on the simple criterion of proximity in time-consecutive snapshots are useful to identify the trajectories of the particles. However, they become problematic as the motility and/or the density of the particles increases because of the uncertainties on the trajectories that particles have followed during the acquisition time of the images. Here, we report efficient methods for learning parameters of the dynamics of the particles from their positions in time-consecutive images. Our algorithm belongs to the class of message-passing algorithms, also known in computer science, information theory and statistical physics under the name of Belief Propagation (BP). The algorithm is distributed, thus allowing parallel implementation suitable for computations on multiple machines without significant inter-machine overhead. We test our method on the model example of particle tracking in turbulent flows, which is particularly challenging due to the strong transport that those flows produce. Our numerical experiments show that the BP algorithm compares in quality with exact Markov Chain Monte-Carlo algorithms, yet BP is far superior in speed. We also suggest and analyze a random-distance model that provides theoretical justification for BP accuracy. Methods developed here systematically formulate the problem of particle tracking and provide fast and reliable tools for its extensive range of applications.

  3. Passive target tracking using marginalized particle filter

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A marginalized particle filtering(MPF)approach is proposed for target tracking under the background of passive measurement.Essentially,the MPF is a combination of particle filtering technique and Kalman filter.By making full use of marginalization,the distributions of the tractable linear part of the total state variables are updated analytically using Kalman filter,and only the lower-dimensional nonlinear state variable needs to be dealt with using particle filter.Simulation studies are performed on an illustrative example,and the results show that the MPF method leads to a significant reduction of the tracking errors when compared with the direct particle implementation.Real data test results also validate the effectiveness of the presented method.

  4. Tracking of human head with particle filter

    Institute of Scientific and Technical Information of China (English)

    GUO Chao

    2009-01-01

    To cope with the problem of tracking a human head in a complicated scene, we propose a method that adopts human skin color and hair color integrated with a kind of particle filter named condensation algorithm. Firstly, a novel method is presented to set up human head color model using skin color and hair color separately based on region growing. Compared with traditional human face model, this method is more precise and works well when human turns around and the face disappears in the image. Then a novel method is presented to use color model in condensation algorithm more effectively. In this method, a combination of edge detection result, color segmentation result and color edge detection result in an Omega window is used to measure the scale and position of human head in condensation. Experiments show that this approach can track human head in complicated scene even when human turns around or the distance of tracking a human head changes quickly.

  5. Detection of single atoms in particle tracks

    International Nuclear Information System (INIS)

    The one-atom detection technique was used to search for atoms which are created from the neutralization of heavy ions as they lose their energy in a gas. When 252Cf decays by binary fission, Cs/super n+/ ions are formed approximately 14% of the time (in the heavy mass peak). Thus, these ions were injected into a gas at a low rate such that the Cs neutral atom could be searched for individually and at a known time after its production. A delay of a few microseconds allowed time for collection of the 3 x 106 electrons created by the 80-MeV Cs/sup n+/ energy; then a pulsed laser was fired along each particle track to remove one electron from each Cs atom by the saturated two-step resonance ionization process. These electrons were then drifted into a gas proportional counter and detected individually to measure the probability that a neutral Cs atom would be found at the end of the fission particle track. The results show that a Cs neutral species is formed about 14% of the time, and thus nearly all Cs/sup n+/ ions become Cs0 when the ions are thermalized in P-10 (90% Ar plus 10% CH4) counting gas. Extensions of the technique to obtain other details of particle track structure are discussed. For example, it is possible to detect even one negative ion created in a track where nearly 100 MeV of energy is absorbed; it is likewise possible to determine the population of quantum-selected excited states left in the wake of these tracks. 4 figures

  6. Nuclear track radiography of 'hot' aerosol particles

    CERN Document Server

    Boulyga, S F; Kievets, M K; Lomonosova, E M; Zhuk, I V; Yaroshevich, O I; Perelygin, V P; Petrova, R I; Brandt, R; Vater, P

    1999-01-01

    Nuclear track radiography was applied to identify aerosol 'hot' particles which contain elements of nuclear fuel and fallout after Chernobyl NPP accident. For the determination of the content of transuranium elements in radioactive aerosols the measurement of the alpha-activity of 'hot' particles by SSNTD was used in this work, as well as radiography of fission fragments formed as a result of the reactions (n,f) and (gamma,f) in the irradiation of aerosol filters by thermal neutrons and high energy gamma quanta. The technique allowed the sizes and alpha-activity of 'hot' particles to be determined without extracting them from the filter, as well as the determination of the uranium content and its enrichment by sup 2 sup 3 sup 5 U, sup 2 sup 3 sup 9 Pu and sup 2 sup 4 sup 1 Pu isotopes. Sensitivity of determination of alpha activity by fission method is 5x10 sup - sup 6 Bq per particle. The software for the system of image analysis was created. It ensured the identification of track clusters on an optical imag...

  7. Particle Filter with Gaussian Weighting for Human Tracking

    OpenAIRE

    T. Basaruddin; M. Rahmat Widyanto; Indah Agustien Siradjuddin

    2012-01-01

    Particle filter for object tracking could achieve high tracking accuracy.  To track the object, this method generates a number of particles which is the representation of the candidate target object.  The location of target object is determined by particles and each weight. The disadvantage of conventional particle filter is the computational time especially on the computation of particle’s weight.  Particle filter with Gaussian weighting is proposed to accomplish the computational problem.  ...

  8. Biological Insights from Single-Particle Tracking in Living Cells

    OpenAIRE

    Sanamrad, Arash

    2014-01-01

    Single-particle tracking is a technique that allows for quantitative analysis of the localization and movement of particles. In this technique, trajectories are constructed by determining and connecting the positions of individual particles from consecutive images. Recent advances have made it possible to track hundreds of particles in an individual cell by labeling the particles of interest with photoactivatable or photoconvertible fluorescent proteins and tracking one or a few at a time. Si...

  9. Extending particle tracking capability with Delaunay triangulation.

    Science.gov (United States)

    Chen, Kejia; Anthony, Stephen M; Granick, Steve

    2014-04-29

    Particle tracking, the analysis of individual moving elements in time series of microscopic images, enables burgeoning new applications, but there is need to better resolve conformation and dynamics. Here we describe the advantages of Delaunay triangulation to extend the capabilities of particle tracking in three areas: (1) discriminating irregularly shaped objects, which allows one to track items other than point features; (2) combining time and space to better connect missing frames in trajectories; and (3) identifying shape backbone. To demonstrate the method, specific examples are given, involving analyzing the time-dependent molecular conformations of actin filaments and λ-DNA. The main limitation of this method, shared by all other clustering techniques, is the difficulty to separate objects when they are very close. This can be mitigated by inspecting locally to remove edges that are longer than their neighbors and also edges that link two objects, using methods described here, so that the combination of Delaunay triangulation with edge removal can be robustly applied to processing large data sets. As common software packages, both commercial and open source, can construct Delaunay triangulation on command, the methods described in this paper are both computationally efficient and easy to implement.

  10. Particle Filtering Applied to Musical Tempo Tracking

    Directory of Open Access Journals (Sweden)

    Macleod Malcolm D

    2004-01-01

    Full Text Available This paper explores the use of particle filters for beat tracking in musical audio examples. The aim is to estimate the time-varying tempo process and to find the time locations of beats, as defined by human perception. Two alternative algorithms are presented, one which performs Rao-Blackwellisation to produce an almost deterministic formulation while the second is a formulation which models tempo as a Brownian motion process. The algorithms have been tested on a large and varied database of examples and results are comparable with the current state of the art. The deterministic algorithm gives the better performance of the two algorithms.

  11. Improvement of Multi-Particle Tracking Code COMA

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>COMA is a multi-particle tracking code for cyclotrons. It was developed by TRIUMF in 1975[1]. The code simulates particle acceleration by performing successive transformations on the particle co-ordinates

  12. Discovery Mondays - The detectors: tracking particles

    CERN Multimedia

    2005-01-01

    View of a module from the LHCb vertex detector, which will be presented at the next Discovery Monday. How do you observe the invisible? In order to deepen still further our knowledge of the infinitely small, physicists accelerate beams of particles and generate collisions between them at extraordinary energies. The collisions give birth to showers of new particles. What are they? In order to find out, physicists slip into the role of detectives thanks to the detectors. At the next Discovery Monday you will find out about the different methods used at CERN to detect particles. A cloud chamber will allow you to see the tracks of cosmic particles live. You will also be given the chance to see real modules for the ATLAS and for the LHCb experiments. Strange materials will be on hand, such as crystals that are heavier than iron and yet as transparent as glass... Come to the Microcosm and become a top detective yourself! This event will take place in French. Join us at the Microcosm (Reception Building 33, M...

  13. User's manual for the particle tracking model ZOOPT

    OpenAIRE

    Jackson, C.R.

    2004-01-01

    This report describes the development of a steady-state particle tracking code for use in conjunction with the object-oriented groundwater flow model, ZOOMQ3D (Jackson and Spink, 2004). Like the flow model, the particle tracking software, ZOOPT, is written using an object-oriented approach to promote its extensibility and flexibility. ZOOPT enables the definition of steady-state and time-variant path lines in three dimensions. Particles can be tracked in both the forward and re...

  14. COLLABORATIVE TRACKING VIA PARTICLE FILTER IN WIRELESS SENSOR NETWORKS

    Institute of Scientific and Technical Information of China (English)

    Yan Zhenya; Zheng Baoyu; Xu Li; Li Shitang

    2008-01-01

    Target tracking is one of the main applications of wireless sensor networks. Optimized computation and energy dissipation are critical requirements to save the limited resource of the sensor nodes. A framework and analysis for collaborative tracking via particle filter are presented in this paper.Collaborative tracking is implemented through sensor selection, and results of tracking are propagated among sensor nodes. In order to save communication resources, a new Ganssian sum particle filter,called Gaussian sum quasi particle filter, to perform the target tracking is presented, in which only mean and covariance of mixands need to be communicated. Based on the Gaussian sum quasi particle filter, a sensor selection criterion is proposed, which is computationally much simpler than other sensor selection criterions. Simulation results show that the proposed method works well for target tracking.

  15. Target tracking in glint noise using a MCMC particle filter

    Institute of Scientific and Technical Information of China (English)

    Hu Hongtao; Jing Zhongliang; Li Anping; Hu Shiqiang; Tian Hongwei

    2005-01-01

    In radar target tracking application, the observation noise is usually non-Gaussian, which is also referred as glint noise. The performances of conventional trackers degra de severely in the presence of glint noise. An improved particle filter, Markov chain Monte Carlo particle filter (MCMC-PF), is applied to cope with radar target tracking when the measurements are perturbed by glint noise. Tracking performance of the filter is demonstrated in the present of glint noise by computer simulation.

  16. Particle Tracking in Circular Accelerators Using the Exact Hamiltonian in SixTrack

    CERN Document Server

    Fjellstrom, Mattias; Hansson, Johan

    2013-12-13

    Particle motion in accelerators is in general complex. Tracking codes are developed to simulate beam dynamics in accelerators. SixTrack is a long lived particle tracking code maintained at CERN, the European Organization for Nuclear Research. A particle accelerator consists of a large number of magnets and other electromagnetic devices that guide the particle through the accelerator. Each device defines its own equation of motion, which often cannot be solved exactly. For this purpose, a number of approximations are introduced in order to facilitate the solution and to speed up the computation. In a high-energy accelerator, the particle has small transverse momentum components. This is exploited in the small-angle approximation. In this approximation the equations of motion are expanded to a low order in the transverse momentum components. In low-energy particle accelerators, or in tracking with large momentum deviations, this approximation is invalid. The equations of motion of a particle passing through a f...

  17. Hybrid Particle and Kalman Filtering for Pupil Tracking in Active IR Illumination Gaze Tracking System

    OpenAIRE

    Jian-nan Chi; Li-hua Xie; Peng-yun Zhang; Yi-fang Lu; Guo-sheng Zhang

    2014-01-01

    A novel pupil tracking method is proposed by combining particle filtering and Kalman filtering for the fast and accurate detection of pupil target in an active infrared source gaze tracking system. Firstly, we utilize particle filtering to track pupil in synthesis triple-channel color map (STCCM) for the fast detection and develop a comprehensive pupil motion model to conduct and analyze the randomness of pupil motion. Moreover, we built a pupil observational model based on the similarity mea...

  18. Registration of light particles by a CN-track detector

    International Nuclear Information System (INIS)

    The validity of the track formation model proposed by Fleischer, Price and Walker was tested for a sensitive cellulose nitrate track detector using protons, deuterons and α particles. Quantitative data are given on the threshold energies and etchable track lengths of these particles. The same data were also calculated for 3H, 3He, 6H, and 8He by means of the model of primary radiation density presented in the paper. A simple empirical relation was found for the evolution of the etch ratio along the particle trajectory. (author)

  19. Optical tracking of nanoscale particles in microscale environments

    Science.gov (United States)

    Mathai, P. P.; Liddle, J. A.; Stavis, S. M.

    2016-03-01

    The trajectories of nanoscale particles through microscale environments record useful information about both the particles and the environments. Optical microscopes provide efficient access to this information through measurements of light in the far field from nanoparticles. Such measurements necessarily involve trade-offs in tracking capabilities. This article presents a measurement framework, based on information theory, that facilitates a more systematic understanding of such trade-offs to rationally design tracking systems for diverse applications. This framework includes the degrees of freedom of optical microscopes, which determine the limitations of tracking measurements in theory. In the laboratory, tracking systems are assemblies of sources and sensors, optics and stages, and nanoparticle emitters. The combined characteristics of such systems determine the limitations of tracking measurements in practice. This article reviews this tracking hardware with a focus on the essential functions of nanoparticles as optical emitters and microenvironmental probes. Within these theoretical and practical limitations, experimentalists have implemented a variety of tracking systems with different capabilities. This article reviews a selection of apparatuses and techniques for tracking multiple and single particles by tuning illumination and detection, and by using feedback and confinement to improve the measurements. Prior information is also useful in many tracking systems and measurements, which apply across a broad spectrum of science and technology. In the context of the framework and review of apparatuses and techniques, this article reviews a selection of applications, with particle diffusion serving as a prelude to tracking measurements in biological, fluid, and material systems, fabrication and assembly processes, and engineered devices. In so doing, this review identifies trends and gaps in particle tracking that might influence future research.

  20. Optical tracking of nanoscale particles in microscale environments

    Science.gov (United States)

    Mathai, P. P.; Liddle, J. A.; Stavis, S. M.

    2016-01-01

    The trajectories of nanoscale particles through microscale environments record useful information about both the particles and the environments. Optical microscopes provide efficient access to this information through measurements of light in the far field from nanoparticles. Such measurements necessarily involve trade-offs in tracking capabilities. This article presents a measurement framework, based on information theory, that facilitates a more systematic understanding of such trade-offs to rationally design tracking systems for diverse applications. This framework includes the degrees of freedom of optical microscopes, which determine the limitations of tracking measurements in theory. In the laboratory, tracking systems are assemblies of sources and sensors, optics and stages, and nanoparticle emitters. The combined characteristics of such systems determine the limitations of tracking measurements in practice. This article reviews this tracking hardware with a focus on the essential functions of nanoparticles as optical emitters and microenvironmental probes. Within these theoretical and practical limitations, experimentalists have implemented a variety of tracking systems with different capabilities. This article reviews a selection of apparatuses and techniques for tracking multiple and single particles by tuning illumination and detection, and by using feedback and confinement to improve the measurements. Prior information is also useful in many tracking systems and measurements, which apply across a broad spectrum of science and technology. In the context of the framework and review of apparatuses and techniques, this article reviews a selection of applications, with particle diffusion serving as a prelude to tracking measurements in biological, fluid, and material systems, fabrication and assembly processes, and engineered devices. In so doing, this review identifies trends and gaps in particle tracking that might influence future research. PMID:27213022

  1. Positron emission particle tracking-Application and labelling techniques

    Institute of Scientific and Technical Information of China (English)

    David J.Parker; Xianfeng Fan

    2008-01-01

    The positron emission particle tracking (PEPT) technique has been widely used in science and engineering to obtain detailed information on the motion and flow fields of fluids or granular materials in multiphase systems, for example, fluids in rock cracks, chemical reactors and food processors; dynamic behaviour of granular materials in chemical reactors, granulators, mixers, dryers, rotating kilns and ball mills. The information obtained by the PEPT technique can be used to optimise the design, operational conditions for a wide range of industrial process systems, and to evaluate modelling work. The technique is based on tracking radioactively labelled particles (up to three particles) by detecting the pairs of back-to-back 511 ke V -γ-rays arising from annihilation of emitted positrons. It therefore involves a positron camera, location algorithms for calculating the tracer location and speed, and tracer labelling techniques. This paper will review the particle tracking technique from tracking algorithm, tracer labelling to their application.

  2. 3D particle tracking velocimetry using dynamic discrete tomography

    CERN Document Server

    Alpers, Andreas; Moseev, Dmitry; Salewski, Mirko

    2013-01-01

    Particle tracking velocimetry in 3D is becoming an increasingly important imaging tool in the study of fluid dynamics, combustion as well as plasmas. We introduce a dynamic discrete tomography algorithm for reconstructing particle trajectories from projections. The algorithm is efficient for data from two projection directions and exact in the sense that it finds a solution consistent with the experimental data. Non-uniqueness of solutions can be detected and solutions can be tracked individually.

  3. PARTICLE FILTER BASED VEHICLE TRACKING APPROACH WITH IMPROVED RESAMPLING STAGE

    Directory of Open Access Journals (Sweden)

    Wei Leong Khong

    2014-02-01

    Full Text Available Optical sensors based vehicle tracking can be widely implemented in traffic surveillance and flow control. The vast development of video surveillance infrastructure in recent years has drawn the current research focus towards vehicle tracking using high-end and low cost optical sensors. However, tracking vehicles via such sensors could be challenging due to the high probability of changing vehicle appearance and illumination, besides the occlusion and overlapping incidents. Particle filter has been proven as an approach which can overcome nonlinear and non-Gaussian situations caused by cluttered background and occlusion incidents. Unfortunately, conventional particle filter approach encounters particle degeneracy especially during and after the occlusion. Particle filter with sampling important resampling (SIR is an important step to overcome the drawback of particle filter, but SIR faced the problem of sample impoverishment when heavy particles are statistically selected many times. In this work, genetic algorithm has been proposed to be implemented in the particle filter resampling stage, where the estimated position can converge faster to hit the real position of target vehicle under various occlusion incidents. The experimental results show that the improved particle filter with genetic algorithm resampling method manages to increase the tracking accuracy and meanwhile reduce the particle sample size in the resampling stage.

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

    Directory of Open Access Journals (Sweden)

    Mohan M. Trivedi

    2008-04-01

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

  5. Multiple object detection and tracking with pseudo-particle filter

    Institute of Scientific and Technical Information of China (English)

    Baolong GUO; Wei SUN

    2009-01-01

    To tackle the divergence of the classical particle filter method for multiple object tracking in image sequences, a new particle filter, called pseudoparticle filter (PPF), is proposed. The PPF invokes subset particles of generic particle filters to form a continuous estimate of the posterior density function of the objects.After sampling-importance resampling (SIR), the subset particles converge to the observations. It is proved that,using an appropriate kernel function of the mean shiift algorithm, we can get the subset particles of the observations and the fixed points of clustering results as the state of the objects. A multiple object data association and state estimation technique is proposed to resolve the subset particles correspondence ambiguities that arise when multiple objects are present. Experimental results demonstrate the efficiency and effectiveness of the algorithm for single and multiple object tracking.

  6. Alpha particle track coloration in CR-39: Improved observability

    CERN Document Server

    Oezguemues, A

    1999-01-01

    A comparative study of the observability of alpha particle tracks in CR-39 was performed with an optical microscope before and after coloration. The implantation of ink helped in observing the damage zones. At first glance through the microscope, the coloration makes the tracks stand out right away. This coloration is helpful, from the start, in the morphological study of the tracks (size, area, orientation, shape, perimeter). This operation is advantageous in distinguishing the alpha particle tracks from stains or scratches. Thus, the routine counting of the tracks is more easily performed. Consequently, this procedure allowed us: to decrease significantly the standard deviation of the approximate total of the parameters given from the image analysis system (Olympus CUE2); to envision the possibility of reasonably decreasing the etching time in order to limit the loss of information caused by the destruction of the CR-39 during chemical etching and to use a weaker enlarging lens in order to cover a larger fi...

  7. 3D particle tracking velocimetry using dynamic discrete tomography

    NARCIS (Netherlands)

    Alpers, A.; Gritzmann, P.; Moseev, D.; Salewski, M.

    2015-01-01

    Particle tracking velocimetry in 3D is becoming an increasingly important imaging tool in the study of fluid dynamics and combustion as well as plasmas. We introduce a dynamic discrete tomography algorithm for reconstructing particle trajectories from projections. The algorithm is efficient for data

  8. 3D particle tracking velocimetry using dynamic discrete tomography

    DEFF Research Database (Denmark)

    Alpers, Andreas; Gritzmann, Peter; Moseev, Dmitry;

    2015-01-01

    Particle tracking velocimetry in 3D is becoming an increasingly important imaging tool in the study of fluid dynamics and combustion as well as plasmas. We introduce a dynamic discrete tomography algorithm for reconstructing particle trajectories from projections. The algorithm is efficient...

  9. Near-wall velocity measurements by Particle-Shadow-Tracking

    CERN Document Server

    Lancien, Pierre; Métivier, François; 10.1007/s00348-007-0260-z

    2009-01-01

    We report a new method to measure the velocity of a fluid in the vicinity of a wall. The method, that we call Particle-Shadow Tracking (PST), simply consists in seeding the fluid with a small number of fine tracer particles of density close to that of the fluid. The position of each particle and of its shadow on the wall are then tracked simultaneously, allowing one to accurately determine the distance separating tracers from the wall and therefore to extract the velocity field. We present an application of the method to the determination of the velocity profile inside a laminar density current flowing along an inclined plane.

  10. Nuclear Track Detectors for Particle Searches

    CERN Document Server

    Manzoor, S; Cozzi, M; Errico, M; Giacomelli, G; Giorgini, M; Kumar, A; Margiotta, A; Medinaceli, E; Patrizii, L; Popa, V; Qureshi, I E; Togo, V

    2007-01-01

    In this paper we report a search for intermediate mass magnetic monopoles and nuclearites using CR39 and Makrofol Nuclear Track Detectors (NTDs) of the SLIM large area experiment, 440 m^2 exposed at the high altitude laboratory of Chacaltaya (Bolivia) and about 100 m^2 at Koksil, Himalaya (Pakistan). We discuss the new chemical etching and improved analysis of the SLIM CR39 sheets. Preliminary limits are based on 316 $m^2$ of CR39 NTDs exposed for 3.9 y.

  11. Discovery Mondays - The detectors: tracking particles

    CERN Multimedia

    2005-01-01

    View of a module from the LHCb vertex detector, which will be presented at the next Discovery Monday. How do you observe the invisible? In order to deepen still further our knowledge of the infinitely small, physicists accelerate beams of particles at close to the speed of light, then generate collisions between them at extraordinary energies, giving birth to showers of new particles. What are these particles? In order to find out, physicists transform themselves into detectives with the help of the detectors. Located around the collision area, these exceptional machines are made up of various layers, each of which detects and measures specific properties of the particles that travel through them. Powerful computers then reconstruct their trajectory and record their charge, mass and energy in order to build up a kind of particle ID card. At the next Discovery Monday you will be able to find out about the different methods used at CERN to detect particles. A cloud chamber will provide live images of the trac...

  12. Integrating the Projective Transform with Particle Filtering for Visual Tracking

    Directory of Open Access Journals (Sweden)

    Beghdadi A

    2011-01-01

    Full Text Available This paper presents the projective particle filter, a Bayesian filtering technique integrating the projective transform, which describes the distortion of vehicle trajectories on the camera plane. The characteristics inherent to traffic monitoring, and in particular the projective transform, are integrated in the particle filtering framework in order to improve the tracking robustness and accuracy. It is shown that the projective transform can be fully described by three parameters, namely, the angle of view, the height of the camera, and the ground distance to the first point of capture. This information is integrated in the importance density so as to explore the feature space more accurately. By providing a fine distribution of the samples in the feature space, the projective particle filter outperforms the standard particle filter on different tracking measures. First, the resampling frequency is reduced due to a better fit of the importance density for the estimation of the posterior density. Second, the mean squared error between the feature vector estimate and the true state is reduced compared to the estimate provided by the standard particle filter. Third, the tracking rate is improved for the projective particle filter, hence decreasing track loss.

  13. Luminescent Sensors for Tracking Spatial Particle Distribution in an Explosion

    Science.gov (United States)

    Eilers, Hergen; Gunawidjaja, Ray; Diez-Y-Riega, Helena; Svingala, Forrest; Daniels, Amber; Lightstone, James; Washington State University Collaboration; Nswc Iheodtd Collaboration

    2015-06-01

    We previously developed and tested thermally sensitive particles that, when seeded into an explosive event, flow with the expanding post-detonation fireball and provide ex-situ measurements of this thermal environment. This current work presents the development and testing of tracking particles that are used in concert with the thermally sensitive particles to encode the initial positions of materials recovered for ex-situ analysis. These tracking sensors consist of fully-crystallized (c) rare-earth-doped yttria particles such as c-Dy:Y2O3, c-Sm:Y2O3, and c-Er,Yb:Y2O3. The temperature sensors consist of mixtures of precursor (p) and fully crystallized materials such as p-Eu:Y2O3/c-Tb:Y2O3 orp-Eu:ZrO2/c-Tb:Y2O3. Three mixtures containing one of the tracking sensors and one of the temperature sensing mixtures are placed at different locations within the chamber. Post-detonation, the tracking particles in the debris are excited by 365 nm light, resulting in different color luminescence, and allowing for potential visual inspection of the particle distribution originating from the different locations. Meanwhile, the temperature is determined from spectral changes of the precursor sensor materials or by comparison of the precursor sensor materials with the Tb:Y2O3 intensity reference. Defense Threat Reduction Agency, HDTRA1-10-1-0005.

  14. A modified variable rate particle filter for maneuvering target tracking

    Institute of Scientific and Technical Information of China (English)

    Yun-fei GUO; Kong-shuai FAN; Dong-liang PENG; Ji-an LUO; Han SHENTU

    2015-01-01

    To address the problem of maneuvering target tracking, where the target trajectory has prolonged smooth regions and abrupt maneuvering regions, a modifi ed variable rate particle fi lter (MVRPF) is proposed. First, a Cartesian-coordinate based variable rate model is presented. Compared with conventional variable rate models, the proposed model does not need any prior knowledge of target mass or external forces. Consequently, it is more convenient in practical tracking applications. Second, a maneuvering detection strategy is adopted to adaptively adjust the parameters in MVRPF, which helps allocate more state points at high maneuver regions and fewer at smooth regions. Third, in the presence of small measurement errors, the unscented particle fi lter, which is embedded in MVRPF, can move more particles into regions of high likelihood and hence can improve the tracking performance. Simulation results illustrate the effectiveness of the proposed method.

  15. Object Tracking Using a Particle Filter with SURF Feature

    Institute of Scientific and Technical Information of China (English)

    Shinfeng DLin; Yu-Ting Jiang; Jia-Jen Lin

    2014-01-01

    In this paper, a novel object tracking based on a particle filter and speeded up robust feature (SURF) is proposed, which uses both color and SURF features. The SURF feature makes the tracking result more robust. On the other hand, the particle selection can lead to save time. In addition, we also consider the matched particle applicable to calculating the SURF weight. Owing to the color, spatial, and SURF features being adopted, this method is more robust than the traditional color-based appearance model. Experimental results demonstrate the robustness and accurate tracking results with challenging sequences. Besides, the proposed method outperforms other methods during the intersection of similar color and object’s partial occlusion.

  16. Target tracking in infrared imagery using a novel particle filter

    Institute of Scientific and Technical Information of China (English)

    Fanglin Wang; Erqi Liu; Jie Yang; Shengyang Yu; Yue Zhou

    2009-01-01

    To address two challenging problems in infrared target tracking, target appearance changes and unpre-dictable abrupt motions, a novel particle filtering based tracking algorithm is introduced. In this method, a novel saliency model is proposed to distinguish the salient target from background, and the eigenspace model is invoked to adapt target appearance changes. To account for the abrupt motions efficiently, a two-step sampling method is proposed to combine the two observation models. The proposed tracking method is demonstrated through two real infrared image sequences, which include the changes of luminance and size, and the drastic abrupt motions of the target.

  17. Video Based Moving Object Tracking by Particle Filter

    Directory of Open Access Journals (Sweden)

    Md. Zahidul Islam

    2009-03-01

    Full Text Available Usually, the video based object tracking deal with non-stationary image stream that changes over time. Robust and Real time moving object tracking is a problematic issue in computer vision research area. Most of the existing algorithms are able to track only inpredefined and well controlled environment. Some cases, they don’t consider non-linearity problem. In our paper, we develop such a system which considers color information, distance transform (DT based shape information and also nonlinearity. Particle filtering has been proven very successful for non-gaussian and non-linear estimation problems. We examine the difficulties of video based tracking and step by step we analyze these issues. In our firstapproach, we develop the color based particle filter tracker that relies on the deterministic search of window, whose color content matches a reference histogram model. A simple HSV histogram-based color model is used to develop this observation system. Secondly, wedescribe a new approach for moving object tracking with particle filter by shape information. The shape similarity between a template and estimated regions in the video scene is measured by their normalized cross-correlation of distance transformed images. Our observation system of particle filter is based on shape from distance transformed edge features. Template is created instantly by selecting any object from the video scene by a rectangle. Finally, inthis paper we illustrate how our system is improved by using both these two cues with non linearity.

  18. Periodic Poisson Solver for Particle Tracking

    CERN Document Server

    Dohlus, M

    2015-01-01

    A method is described to solve the Poisson problem for a three dimensional source distribution that is periodic into one direction. Perpendicular to the direction of periodicity a free space (or open) boundary is realized. In beam physics, this approach allows to calculate the space charge field of a continualized charged particle distribution with periodic pattern. The method is based on a particle mesh approach with equidistant grid and fast convolution with a Green's function. The periodic approach uses only one period of the source distribution, but a periodic extension of the Green's function. The approach is numerically efficient and allows the investigation of periodic- and pseudo-periodic structures with period lengths that are small compared to the source dimensions, for instance of laser modulated beams or of the evolution of micro bunch structures. Applications for laser modulated beams are given.

  19. Particle Tracking and Deposition from CFD Simulations using a Viscoelastic Particle Model

    NARCIS (Netherlands)

    Losurdo, M.

    2009-01-01

    In the present dissertation the mathematical modelling of particle deposition is studied and the solution algorithms for particle tracking, deposition and deposit growth are developed. Particle deposition is modelled according to mechanical impact and contact mechanics taking into account the depend

  20. A novel particle tracking algorithm using polar coordinate system similarity

    Institute of Scientific and Technical Information of China (English)

    Xiaodong Ruan; Wenfeng Zhao; Yunming Chen

    2005-01-01

    A new algorithm using polar coordinate system similarity (PCSS) for tracking particle in particle tracking velocimetry (PTV) is proposed. The essence of the algorithm is to consider simultaneously the changes of the distance and angle of surrounding particles relative to the object particle.Monte Carlo simulations of a solid body rotational flow and a parallel shearing flow are used to investigate flows measurable by PCSS and the influences of experimental parameters on the implementation of the new algorithm. The results indicate that the PCSS algorithm can be applied to flows subjected to strong rotation and is not sensitive to experimental parameters in comparison with the conventional binary image cross-correlation (BICC) algorithm. Finally, PCSS is applied to images of a real experiment.

  1. SimTrack: A compact c++ library for particle orbit and spin tracking in accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Yun [Brookhaven National Laboratory (BNL), Upton, NY (United States)

    2015-06-24

    SimTrack is a compact c++ library of 6-d symplectic element-by-element particle tracking in accelerators originally designed for head-on beam-beam compensation simulation studies in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It provides a 6-d symplectic orbit tracking with the 4th order symplectic integration for magnet elements and the 6-d symplectic synchro-beam map for beam-beam interaction. Since its inception in 2009, SimTrack has been intensively used for dynamic aperture calculations with beam-beam interaction for RHIC. Recently, proton spin tracking and electron energy loss due to synchrotron radiation were added. In this article, I will present the code architecture, physics models, and some selected examples of its applications to RHIC and a future electron-ion collider design eRHIC.

  2. SimTrack: A compact c++ code for particle orbit and spin tracking in accelerators

    Science.gov (United States)

    Luo, Yun

    2015-11-01

    SimTrack is a compact c++ code of 6-d symplectic element-by-element particle tracking in accelerators originally designed for head-on beam-beam compensation simulation studies in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It provides a 6-d symplectic orbit tracking with the 4th order symplectic integration for magnet elements and the 6-d symplectic synchro-beam map for beam-beam interaction. Since its inception in 2009, SimTrack has been intensively used for dynamic aperture calculations with beam-beam interaction for RHIC. Recently, proton spin tracking and electron energy loss due to synchrotron radiation were added. In this paper, I will present the code architecture, physics models, and some selected examples of its applications to RHIC and a future electron-ion collider design eRHIC.

  3. A Voronoi Grid and a Particle Tracking Algorithm for DSMC

    OpenAIRE

    Stollmeier, Frank; Grabe, Martin

    2011-01-01

    The DSMC method simulates a gas by three uncoupled steps: moving representative particles through a physical domain, performing probabilistic collisions and estimating the macroscopic state by ensemble averaging. In order to ease computational treatment of these three steps it is convenient to discretize the space with a grid that fits into the boundaries of the physical domain. For efficient particle tracking it is useful that the cells of this grid are convex polyhedra which pr...

  4. Evaluation of a digital optical ionizing radiation particle track detector

    International Nuclear Information System (INIS)

    An ionizing radiation particle track detector is outlined which can, in principle, determine the three-dimensional spatial distribution of all the secondary electrons produced by the passage of ionizing radiation through a low-pressure (0.1 to 10 kPa) gas. The electrons in the particle track are excited by the presence of a high-frequency AC electric field, and two digital cameras image the optical radiation produced in electronic excitation collisions of the surroundings gas by the electrons. The specific requirements of the detector for neutron dosimetry and microdosimetry are outlined (i.e., operating conditions of the digital cameras, high voltage fields, gas mixtures, etc.) along with an estimate of the resolution and sensitivity achievable with this technique. The proposed detector is shown to compare favorable with other methods for obtaining the details of the track structure, particularly in the quality of the information obtainable about the particle track and the comparative simplicity and adaptability of the detector for measuring the secondary electron track structure for many forms of ionizing radiation over a wide range of energies

  5. Tracking Intermittently Speaking Multiple Speakers Using a Particle Filter

    Directory of Open Access Journals (Sweden)

    Quinlan Angela

    2009-01-01

    Full Text Available The problem of tracking multiple intermittently speaking speakers is difficult as some distinct problems must be addressed. The number of active speakers must be estimated, these active speakers must be identified, and the locations of all speakers including inactive speakers must be tracked. In this paper we propose a method for tracking intermittently speaking multiple speakers using a particle filter. In the proposed algorithm the number of active speakers is firstly estimated based on the Exponential Fitting Test (EFT, a source number estimation technique which we have proposed. The locations of the speakers are then tracked using a particle filtering framework within which the decomposed likelihood is used in order to decouple the observed audio signal and associate each element of the decomposed signal with an active speaker. The tracking accuracy is then further improved by the inclusion of a silence region detection step and estimation of the noise-only covariance matrix. The method was evaluated using live recordings of 3 speakers and the results show that the method produces highly accurate tracking results.

  6. Physical Models for Particle Tracking Simulations in the RF Gap

    Energy Technology Data Exchange (ETDEWEB)

    Shishlo, Andrei P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holmes, Jeffrey A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-06-01

    This document describes the algorithms that are used in the PyORBIT code to track the particles accelerated in the Radio-Frequency cavities. It gives the mathematical description of the algorithms and the assumptions made in each case. The derived formulas have been implemented in the PyORBIT code. The necessary data for each algorithm are described in detail.

  7. 3D Visual Tracking with Particle and Kalman Filters

    OpenAIRE

    Bayramli, Burak

    2010-01-01

    One of the most visually demonstrable and straightforward uses of filtering is in the field of Computer Vision. In this document we will try to outline the issues encountered while designing and implementing a particle and kalman filter based tracking system.

  8. Adaptive mean-shift tracking with auxiliary particles.

    Science.gov (United States)

    Wang, Junqiu; Yagi, Yasushi

    2009-12-01

    We present a new approach for robust and efficient tracking by incorporating the efficiency of the mean-shift algorithm with the multihypothesis characteristics of particle filtering in an adaptive manner. The aim of the proposed algorithm is to cope with problems that were brought about by sudden motions and distractions. The mean-shift tracking algorithm is robust and effective when the representation of a target is sufficiently discriminative, the target does not jump beyond the bandwidth, and no serious distractions exist. We propose a novel two-stage motion estimation method that is efficient and reliable. If a sudden motion is detected by the motion estimator, some particle-filtering-based trackers can be used to outperform the mean-shift algorithm, at the expense of using a large particle set. In our approach, the mean-shift algorithm is used, as long as it provides reasonable performance. Auxiliary particles are introduced to cope with distractions and sudden motions when such threats are detected. Moreover, discriminative features are selected according to the separation of the foreground and background distributions when threats do not exist. This strategy is important, because it is dangerous to update the target model when the tracking is in an unsteady state. We demonstrate the performance of our approach by comparing it with other trackers in tracking several challenging image sequences.

  9. Bearings-Only Tracking of Manoeuvring Targets Using Particle Filters

    Directory of Open Access Journals (Sweden)

    M. Sanjeev Arulampalam

    2004-11-01

    Full Text Available We investigate the problem of bearings-only tracking of manoeuvring targets using particle filters (PFs. Three different (PFs are proposed for this problem which is formulated as a multiple model tracking problem in a jump Markov system (JMS framework. The proposed filters are (i multiple model PF (MMPF, (ii auxiliary MMPF (AUX-MMPF, and (iii jump Markov system PF (JMS-PF. The performance of these filters is compared with that of standard interacting multiple model (IMM-based trackers such as IMM-EKF and IMM-UKF for three separate cases: (i single-sensor case, (ii multisensor case, and (iii tracking with hard constraints. A conservative CRLB applicable for this problem is also derived and compared with the RMS error performance of the filters. The results confirm the superiority of the PFs for this difficult nonlinear tracking problem.

  10. Particle Tracking and Deposition from CFD Simulations using a Viscoelastic Particle Model

    OpenAIRE

    Losurdo, M.

    2009-01-01

    In the present dissertation the mathematical modelling of particle deposition is studied and the solution algorithms for particle tracking, deposition and deposit growth are developed. Particle deposition is modelled according to mechanical impact and contact mechanics taking into account the dependency on time, temperature and particle-deposit composition explicitly. Indeed, such a model lies in the field of the rheology of visco-elastic solids which the author of this dissertation refers to...

  11. Optimizing experimental parameters for tracking of diffusing particles

    Science.gov (United States)

    Vestergaard, Christian L.

    2016-08-01

    We describe how a single-particle tracking experiment should be designed in order for its recorded trajectories to contain the most information about a tracked particle's diffusion coefficient. The precision of estimators for the diffusion coefficient is affected by motion blur, limited photon statistics, and the length of recorded time series. We demonstrate for a particle undergoing free diffusion that precision is negligibly affected by motion blur in typical experiments, while optimizing photon counts and the number of recorded frames is the key to precision. Building on these results, we describe for a wide range of experimental scenarios how to choose experimental parameters in order to optimize the precision. Generally, one should choose quantity over quality: experiments should be designed to maximize the number of frames recorded in a time series, even if this means lower information content in individual frames.

  12. Evaluation of nanoparticle tracking analysis for total virus particle determination

    Directory of Open Access Journals (Sweden)

    Kramberger Petra

    2012-11-01

    Full Text Available Abstract The NanoSight LM10 with Nanoparticle tracking analysis (NTA software was evaluated for the quantification of latex particles, adenovirus 5, and influenza virus. The inter-day variability was determined by measuring the same sample over several consecutive days and the method’s accuracy was demonstrated by using known concentrations of the subject particles. NTA analysis was also used to quantify chromatographic fractions of adenovirus and influenza virus after purification on a CIM monolithic column. NTA results were compared and evaluated against hemagglutination (HA and end point dilution assay, determining total and infection virus particle number, respectively. The results demonstrated that nanoparticle tracking analysis is a method for fast estimation of virus concentration in different samples. In addition, it can provide a better insight into the sample status, regarding the level of virus aggregation.

  13. On the optical contrast of particle tracks in nuclear track detectors

    International Nuclear Information System (INIS)

    A study was made of the optical contrast of alpha-particle tracks normally incident on cellulose nitrate at all the phases of their development. Measurements of the optical contrast of the spots were performed using a microdensitometer. It was found that the maximum contrast corresponds to the point at which the particle reaches the end of its trajectory. Comparisons of the results of the present work with those obtained by other methods are discussed. (Auth.)

  14. Collaborative research on fluidization employing computer-aided particle tracking

    International Nuclear Information System (INIS)

    The objective of this work is to obtain unique, fundamental information on fluidization dynamics over a wide range of flow regimes using a Transportable Computer-Aided Particle Tracking Apparatus (TCAPTA). The contractor will design and fabricate a transportable version of the Computer-Aided Particle Tracking Facility (CAPTF) he has previously developed. The contractor will install and operate the (TCAPTA) at the METC fluidization research facilities. Quantitative data on particle motion will be obtained and reduced. The data will be used to provide needed information for modeling of bed dynamics, and prediction of bed performance, including erosion. A radioactive tracer particle, identical in size shape and mass to the bed particles under study, is mixed in the bed. The radiation emitted by the tracer particle, monitored continuously by 16 scintillation detectors, allows its position to be determined as a function of time. Stochastic mixing processes intrinsic to fluidization further cause the particle to travel to all active regions of the bed, thus sampling the motion in these regions. After a long test run to insure that a sufficient sampling have been acquired, time-differentiation and other statistical processing will then yield the mean velocity distribution, the fluctuating velocity distribution, many types of auto- and cross correlations, as well as mean fluxes, including the mean momentum fluxes due to random motion, which represent the kinetic contributions to the mean stress tensor

  15. Tracking Submicron Particles in Microchannel Flow by Microscopic Holography

    Institute of Scientific and Technical Information of China (English)

    罗锐; 刘石

    2012-01-01

    Three-dimensional tracking of submicron particles in flows in a micro-channel was carried out using in-line holographic microscopy.A fixed single 0.5 μm fluorescent particle was identified and isolated from dust particles or overlapped particle pair using the laser induced fluorescent(LIF) method.Then in-line microscopic holograms of the fixed single particle were obtained at different positions on the optical axis,i.e.the defocus distances.The holograms of the single particle were used as the model templates with the known defocus distances.The particles in the in-line microscopic holograms of flow in the microchannel were then identified and located to obtain their two-dimensional positions.The defocus distances of those particles were determined by matching each hologram pattern to one of the model templates obtained in the single particle test.Finally the three-dimensional position and velocity of each particle were obtained.

  16. Channel Tracking Using Particle Filtering in Unresolvable Multipath Environments

    Directory of Open Access Journals (Sweden)

    Tanya Bertozzi

    2004-11-01

    Full Text Available We propose a new timing error detector for timing tracking loops inside the Rake receiver in spread spectrum systems. Based on a particle filter, this timing error detector jointly tracks the delays of each path of the frequency-selective channels. Instead of using a conventional channel estimator, we have introduced a joint time delay and channel estimator with almost no additional computational complexity. The proposed scheme avoids the drawback of the classical early-late gate detector which is not able to separate closely spaced paths. Simulation results show that the proposed detectors outperform the conventional early-late gate detector in indoor scenarios.

  17. Aging in dense suspensions of soft thermosensitive microgel particles studied with particle-tracking microrheology

    NARCIS (Netherlands)

    Ende, van den Dirk; Purnomo, Eko H.; Duits, Michel H.G.; Richtering, Walter; Mugele, Frieder

    2010-01-01

    Using particle tracking microrheology, we studied the glass transition in dense suspensions of thermosensitive microgel particles. These suspensions can be tuned reversibly between the glass state at low temperature and the liquid state at high temperature. In the glass state, the ensemble averaged

  18. Particle filters for object tracking: enhanced algorithm and efficient implementations

    International Nuclear Information System (INIS)

    Object tracking and recognition is a hot research topic. In spite of the extensive research efforts expended, the development of a robust and efficient object tracking algorithm remains unsolved due to the inherent difficulty of the tracking problem. Particle filters (PFs) were recently introduced as a powerful, post-Kalman filter, estimation tool that provides a general framework for estimation of nonlinear/ non-Gaussian dynamic systems. Particle filters were advanced for building robust object trackers capable of operation under severe conditions (small image size, noisy background, occlusions, fast object maneuvers ..etc.). The heavy computational load of the particle filter remains a major obstacle towards its wide use.In this thesis, an Excitation Particle Filter (EPF) is introduced for object tracking. A new likelihood model is proposed. It depends on multiple functions: position likelihood; gray level intensity likelihood and similarity likelihood. Also, we modified the PF as a robust estimator to overcome the well-known sample impoverishment problem of the PF. This modification is based on re-exciting the particles if their weights fall below a memorized weight value. The proposed enhanced PF is implemented in software and evaluated. Its results are compared with a single likelihood function PF tracker, Particle Swarm Optimization (PSO) tracker, a correlation tracker, as well as, an edge tracker. The experimental results demonstrated the superior performance of the proposed tracker in terms of accuracy, robustness, and occlusion compared with other methods Efficient novel hardware architectures of the Sample Important Re sample Filter (SIRF) and the EPF are implemented. Three novel hardware architectures of the SIRF for object tracking are introduced. The first architecture is a two-step sequential PF machine, where particle generation, weight calculation and normalization are carried out in parallel during the first step followed by a sequential re

  19. Particle track structure and its correlation with radiobiological endpoint

    International Nuclear Information System (INIS)

    One of the possible ways to classify track structures is application of conventional partition techniques of analysis of multidimensional data to the track structure. Using these cluster algorithms this paper attempts to find characteristics of radiation reflecting spatial distribution of ionizations in the primary particle track. Absolute frequency distributions of clusters giving the mean number of clusters produced by radiation per unit of deposited energy have been computed for radiations of different qualities. Results were compared with published data of cell inactivation. For particular biological objects the critical properties of radiation correlating with the cell inactivation can be found and it seems that the occurrence of a cluster of at least four ionizations formed in a domain of ∼2-3 nm correlates with the induction of double strand break. (author)

  20. The Timepix Telescope for high performance particle tracking

    Energy Technology Data Exchange (ETDEWEB)

    Akiba, K. [Federal University of Rio de Janeiro, Rio de Janeiro (Brazil); Ronning, P. [CERN, The European Organisation for Nuclear Research, Geneva (Switzerland); Beuzekom, M. van; Beveren, V. van [NIKHEF, Amsterdam (Netherlands); Borghi, S. [University of Manchester, Manchester, Lancashire (United Kingdom); Boterenbrood, H. [NIKHEF, Amsterdam (Netherlands); Buytaert, J.; Collins, P. [CERN, The European Organisation for Nuclear Research, Geneva (Switzerland); Dosil Suárez, A. [Universidade de Santiago de Compostela, Santiago de Compostela (Spain); Dumps, R. [CERN, The European Organisation for Nuclear Research, Geneva (Switzerland); Eklund, L. [Glasgow University, Glasgow, Lanarkshire (United Kingdom); Esperante, D.; Gallas, A. [Universidade de Santiago de Compostela, Santiago de Compostela (Spain); Gordon, H. [University of Oxford, Oxfordshire (United Kingdom); Heijden, B. van der [NIKHEF, Amsterdam (Netherlands); Hombach, C. [University of Manchester, Manchester, Lancashire (United Kingdom); Hynds, D. [Glasgow University, Glasgow, Lanarkshire (United Kingdom); John, M. [University of Oxford, Oxfordshire (United Kingdom); Leflat, A. [Lomonosov Moscow State University, Moscow (Russian Federation); Li, Y. [University of Oxford, Oxfordshire (United Kingdom); and others

    2013-09-21

    The Timepix particle tracking telescope has been developed as part of the LHCb VELO Upgrade project, supported by the Medipix Collaboration and the AIDA framework. It is a primary piece of infrastructure for the VELO Upgrade project and is being used for the development of new sensors and front end technologies for several upcoming LHC trackers and vertexing systems. The telescope is designed around the dual capability of the Timepix ASICs to provide information about either the deposited charge or the timing information from tracks traversing the 14×14 mm matrix of 55×55μm pixels. The rate of reconstructed tracks available is optimised by taking advantage of the shutter driver readout architecture of the Timepix chip, operated with existing readout systems. Results of tests conducted in the SPS North Area beam facility at CERN show that the telescope typically provides reconstructed track rates during the beam spills of between 3.5 and 7.5 kHz, depending on beam conditions. The tracks are time stamped with 1 ns resolution with an efficiency of above 98% and provide a pointing resolution at the centre of the telescope of ∼1.6μm. By dropping the time stamping requirement the rate can be increased to ∼15kHz, at the expense of a small increase in background. The telescope infrastructure provides CO{sub 2} cooling and a flexible mechanical interface to the device under test, and has been used for a wide range of measurements during the 2011–2012 data taking campaigns. -- Highlights: • We provide a technical description of the Timepix Telescope for particle tracking applications. • We demonstrate the spatial and timing resolution to be 2μm and 1 ns respectively. • The maximum particle rate is 7.5 kHz with highly resolved timing and spacing. • The maximum particle rate is 15 kHz with only highly resolved spacing. • We briefly describe the software and tracking algorithms used to achieve this.

  1. Visual Tracking Using an Insect Vision Embedded Particle Filter

    Directory of Open Access Journals (Sweden)

    Wei Guo

    2015-01-01

    Full Text Available Particle filtering (PF based object tracking algorithms have drawn great attention from lots of scholars. The core of PF is to predict the possible location of the target via the state transition model. One commonly adopted approach is resorting to prior motion cues under the smooth motion assumption, which performs well when the target moves with a relatively stable velocity. However, it would possibly fail if the target is undergoing abrupt motion. To address this problem, inspired by insect vision, we propose a simple yet effective visual tracking framework based on PF. Utilizing the neuronal computational model of the insect vision, we estimate the motion of the target in a novel way so as to refine the position state of propagated particles using more accurate transition mode. Furthermore, we design a novel sample optimization framework where local and global search strategies are jointly used. In addition, we propose a new method to monitor long duration severe occlusion and we could recover the target. Experiments on publicly available benchmark video sequences demonstrate that the proposed tracking algorithm outperforms the state-of-the art methods in challenging scenarios, especially for tracking target which is undergoing abrupt motion or fast movement.

  2. Investigation of granular impact using positron emission particle tracking

    KAUST Repository

    Marston, Jeremy O.

    2015-04-01

    We present results from an experimental study of granular impact using a combination of high-speed video and positron emission particle tracking (PEPT). The PEPT technique exploits the annihilation of photons from positron decay to determine the position of tracer particles either inside a small granular bed or attached to the object which impacts the bed. We use dense spheres as impactors and the granular beds are comprised of glass beads which are fluidised to achieve a range of different initial packing states. For the first time, we have simultaneously investigated both the trajectory of the sphere, the motion of particles in a 3-D granular bed and particles which jump into the resultant jet, which arises from the collapse of the cavity formed by the impacting sphere.

  3. Particle Tracking and Simulation on the .NET Framework

    International Nuclear Information System (INIS)

    Particle tracking and simulation studies are becoming increasingly complex. In addition to the use of more sophisticated graphics, interactive scripting is becoming popular. Compatibility with different control systems requires network and database capabilities. It is not a trivial task to fulfill all the various requirements without sacrificing runtime performance. We evaluated the effectiveness of the .NET framework by converting a C++ simulation code to C. The portability to other platforms is mentioned in terms of Mono

  4. Particle tracking velocimetry of a gliding arc discharge

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas;

    2014-01-01

    A 35 kHz AC gliding arc discharge at atmospheric pressure is generated between two diverging electrodes and extended by an air flow. The gas flow velocity is measured by particle tracking velocimetry (PTV) while the moving velocity of the plasma column of the gliding arc discharge is measured...... by analyzing the movie taken by a high-speed camera. The two-dimensional velocity vector of the gas flow and of the gliding arc in the imaging plane was determined....

  5. 3-D imaging of particle tracks in solid state nuclear track detectors

    Directory of Open Access Journals (Sweden)

    D. Wertheim

    2010-05-01

    Full Text Available It has been suggested that 3 to 5% of total lung cancer deaths in the UK may be associated with elevated radon concentration. Radon gas levels can be assessed using CR-39 plastic detectors which are often assessed by 2-D image analysis of surface images. 3-D analysis has the potential to provide information relating to the angle at which alpha particles impinge on the detector. In this study we used a "LEXT" OLS3100 confocal laser scanning microscope (Olympus Corporation, Tokyo, Japan to image tracks on five CR-39 detectors. We were able to identify several patterns of single and coalescing tracks from 3-D visualisation. Thus this method may provide a means of detailed 3-D analysis of Solid State Nuclear Track Detectors.

  6. 3-D imaging of particle tracks in solid state nuclear track detectors

    Science.gov (United States)

    Wertheim, D.; Gillmore, G.; Brown, L.; Petford, N.

    2010-05-01

    It has been suggested that 3 to 5% of total lung cancer deaths in the UK may be associated with elevated radon concentration. Radon gas levels can be assessed using CR-39 plastic detectors which are often assessed by 2-D image analysis of surface images. 3-D analysis has the potential to provide information relating to the angle at which alpha particles impinge on the detector. In this study we used a "LEXT" OLS3100 confocal laser scanning microscope (Olympus Corporation, Tokyo, Japan) to image tracks on five CR-39 detectors. We were able to identify several patterns of single and coalescing tracks from 3-D visualisation. Thus this method may provide a means of detailed 3-D analysis of Solid State Nuclear Track Detectors.

  7. From Waves to Particle Tracks and Quantum Probabilities

    Science.gov (United States)

    Falkenburg, Brigitte

    Here, the measurement methods for identifying massive charged particles are investigated. They have been used from early cosmic ray studies up to the present day. Laws such as the classical Lorentz force and Einstein's relativistic kinematics were established before the rise of quantum mechanics. Later, it became crucial to measure the energy loss of charged particles in matter. In 1930, Bethe developed a semi-classical model based on the quantum mechanics of scattering. In the early 1930s, he and others calculated the passage of charged particles through matter including pair creation and bremsstrahlung. Due to missing trust in quantum electrodynamics, however, only semi-empirical methods were employed in order to estimate the mass and charge from the features of particle tracks. In 1932, Anderson inserted a lead plate into the cloud chamber in order to determine the flight direction and charge of the `positive electron'. In the 1940s, nuclear emulsions helped to resolve puzzles about particle identification and quantum electrodynamics. Later, the measurement theory was extended in a cumulative process by adding conservation laws for dynamic properties, probabilistic quantum formulas for resonances, scattering cross sections, etc. The measurement method was taken over from cosmic ray studies to the era of particle accelerators, and finally taken back from there to astroparticle physics. The measurement methods remained the same, but in the transition from particle to astroparticle physics the focus of interest shifted. Indeed, the experimental methods of both fields explore the grounds of `new physics' in complementary ways.

  8. Tracking Water Diffusion Fronts in a Highly Viscous Aerosol Particle

    Science.gov (United States)

    Bastelberger, Sandra; Krieger, Ulrich; Peter, Thomas

    2016-04-01

    Field measurements indicate that atmospheric secondary aerosol particles can be present in a highly viscous, glassy state [1]. In contrast to liquid state particles, the gas phase equilibration is kinetically limited and governed by condensed phase diffusion. In recent water diffusion experiments on highly viscous single aerosol particles levitated in an electrodynamic balance (EDB) we observed a characteristic shift behavior of the Mie whispering gallery modes (WGM) indicative of the changing radial structure of the particle, thus providing us with an experimental method to track the diffusion process inside the particle. When a highly viscous, homogeneous particle is exposed to an abrupt increase in relative humidity, the rapid gas phase diffusion and strong concentration dependence of the diffusion coefficient in the condensed phase lead to extremely steep water concentration gradients inside the particle, reminiscent of diffusion fronts. The resulting quasi step-like concentration profile motivates the introduction of a simple core-shell model describing the morphology of the non-equilibrium particle during humidification. The subsequent particle growth and reduction of the shell refractive index can be observed as red and blueshift behavior of the WGM, respectively. The shift pattern can be attributed to a core-shell radius ratio and particle radius derived from model calculations [2]. If supplemented with growth information obtained from the WGM redshift and thermodynamic equilibrium data, we can infer a comprehensive picture of the time evolution of the diffusion fronts in the framework of our core-shell model. The measured time dependent concentration profile is then compared with simulations solving the non-linear diffusion equation [3] [1] Virtanen, A., et al., Nature, 467, 824-827, 2010 [2] Kaiser, T., Schweiger, G., Computers in Physics, Vol. 7, No. 6, 682-686, Nov/Dec 1993 [3] Zobrist, B., Soonsin, V., Luo, B.P., Peter, T. et al., Phys. Chem. Chem

  9. A new neural network for particle-tracking velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Labonte, G. [Royal Military Coll. of Canada, Kingston, ON (Canada). Dept. of Mathematics

    1999-03-01

    We describe a new neural network designed to solve the correspondence problem of particle-tracking velocimetry. Given two successive pictures of marker-particles suspended in a fluid, it matches their images by approximately duplicating the fluid motion. We present the results of efficiency tests that reveal the excellence of its performance and its stability with respect to the presence of unmatchable particle images. We compare its success rate in image matching to that of the neural network of Grant and Pan (1995), and observe that it produces better results when the flows have more important changes in direction. It has the important advantages over the latter, of being better adapted to benefit from parallel computing, and of being self-starting, i.e. of not requiring to be taught about the fluid flow in advance. (orig.) With 4 figs., 16 refs.

  10. Distributed Particle Filter for Target Tracking: With Reduced Sensor Communications

    Science.gov (United States)

    Ghirmai, Tadesse

    2016-01-01

    For efficient and accurate estimation of the location of objects, a network of sensors can be used to detect and track targets in a distributed manner. In nonlinear and/or non-Gaussian dynamic models, distributed particle filtering methods are commonly applied to develop target tracking algorithms. An important consideration in developing a distributed particle filtering algorithm in wireless sensor networks is reducing the size of data exchanged among the sensors because of power and bandwidth constraints. In this paper, we propose a distributed particle filtering algorithm with the objective of reducing the overhead data that is communicated among the sensors. In our algorithm, the sensors exchange information to collaboratively compute the global likelihood function that encompasses the contribution of the measurements towards building the global posterior density of the unknown location parameters. Each sensor, using its own measurement, computes its local likelihood function and approximates it using a Gaussian function. The sensors then propagate only the mean and the covariance of their approximated likelihood functions to other sensors, reducing the communication overhead. The global likelihood function is computed collaboratively from the parameters of the local likelihood functions using an average consensus filter or a forward-backward propagation information exchange strategy. PMID:27618057

  11. Distributed Particle Filter for Target Tracking: With Reduced Sensor Communications.

    Science.gov (United States)

    Ghirmai, Tadesse

    2016-01-01

    For efficient and accurate estimation of the location of objects, a network of sensors can be used to detect and track targets in a distributed manner. In nonlinear and/or non-Gaussian dynamic models, distributed particle filtering methods are commonly applied to develop target tracking algorithms. An important consideration in developing a distributed particle filtering algorithm in wireless sensor networks is reducing the size of data exchanged among the sensors because of power and bandwidth constraints. In this paper, we propose a distributed particle filtering algorithm with the objective of reducing the overhead data that is communicated among the sensors. In our algorithm, the sensors exchange information to collaboratively compute the global likelihood function that encompasses the contribution of the measurements towards building the global posterior density of the unknown location parameters. Each sensor, using its own measurement, computes its local likelihood function and approximates it using a Gaussian function. The sensors then propagate only the mean and the covariance of their approximated likelihood functions to other sensors, reducing the communication overhead. The global likelihood function is computed collaboratively from the parameters of the local likelihood functions using an average consensus filter or a forward-backward propagation information exchange strategy. PMID:27618057

  12. Single particle tracking and single molecule energy transfer

    CERN Document Server

    Bräuchle, Christoph; Michaelis, Jens

    2009-01-01

    Closing a gap in the literature, this handbook gathers all the information on single particle tracking and single molecule energy transfer. It covers all aspects of this hot and modern topic, from detecting virus entry to membrane diffusion, and from protein folding using spFRET to coupled dye systems, as well recent achievements in the field. Throughout, the first-class editors and top international authors present content of the highest quality, making this a must-have for physical chemists, spectroscopists, molecular physicists and biochemists.

  13. Nuclear particle track-etched anti-bogus mark

    International Nuclear Information System (INIS)

    Nuclear particle track-etched anti-bogus mark is a new type of forgery-proof product after engraving gravure printing, thermocolour, fluorescence, laser hologram and metal concealed anti-bogus mark. The mark is manufactured by intricate high technology and the state strictly controlled sensitive nuclear facilities to ensure the mark not to be copied. The pattern of the mark is specially characterized by permeability of liquid to be discriminated from forgery. The genuine mark can be distinguished from sham one by transparent liquid (e.g. water), colorful pen and chemical reagent. The mark has passed the official examination of health safety. It is no danger of nuclear irradiation. (author)

  14. Tri-track: free software for large-scale particle tracking.

    Science.gov (United States)

    Vallotton, Pascal; Olivier, Sandra

    2013-04-01

    The ability to correctly track objects in time-lapse sequences is important in many applications of microscopy. Individual object motions typically display a level of dynamic regularity reflecting the existence of an underlying physics or biology. Best results are obtained when this local information is exploited. Additionally, if the particle number is known to be approximately constant, a large number of tracking scenarios may be rejected on the basis that they are not compatible with a known maximum particle velocity. This represents information of a global nature, which should ideally be exploited too. Some time ago, we devised an efficient algorithm that exploited both types of information. The tracking task was reduced to a max-flow min-cost problem instance through a novel graph structure that comprised vertices representing objects from three consecutive image frames. The algorithm is explained here for the first time. A user-friendly implementation is provided, and the specific relaxation mechanism responsible for the method's effectiveness is uncovered. The software is particularly competitive for complex dynamics such as dense antiparallel flows, or in situations where object displacements are considerable. As an application, we characterize a remarkable vortex structure formed by bacteria engaged in interstitial motility.

  15. Modeling reactive transport with particle tracking and kernel estimators

    Science.gov (United States)

    Rahbaralam, Maryam; Fernandez-Garcia, Daniel; Sanchez-Vila, Xavier

    2015-04-01

    Groundwater reactive transport models are useful to assess and quantify the fate and transport of contaminants in subsurface media and are an essential tool for the analysis of coupled physical, chemical, and biological processes in Earth Systems. Particle Tracking Method (PTM) provides a computationally efficient and adaptable approach to solve the solute transport partial differential equation. On a molecular level, chemical reactions are the result of collisions, combinations, and/or decay of different species. For a well-mixed system, the chem- ical reactions are controlled by the classical thermodynamic rate coefficient. Each of these actions occurs with some probability that is a function of solute concentrations. PTM is based on considering that each particle actually represents a group of molecules. To properly simulate this system, an infinite number of particles is required, which is computationally unfeasible. On the other hand, a finite number of particles lead to a poor-mixed system which is limited by diffusion. Recent works have used this effect to actually model incomplete mix- ing in naturally occurring porous media. In this work, we demonstrate that this effect in most cases should be attributed to a defficient estimation of the concentrations and not to the occurrence of true incomplete mixing processes in porous media. To illustrate this, we show that a Kernel Density Estimation (KDE) of the concentrations can approach the well-mixed solution with a limited number of particles. KDEs provide weighting functions of each particle mass that expands its region of influence, hence providing a wider region for chemical reactions with time. Simulation results show that KDEs are powerful tools to improve state-of-the-art simulations of chemical reactions and indicates that incomplete mixing in diluted systems should be modeled based on alternative conceptual models and not on a limited number of particles.

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

    Directory of Open Access Journals (Sweden)

    Bin Liu

    2013-01-01

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

  17. Shake-The-Box: Lagrangian particle tracking at high particle image densities

    Science.gov (United States)

    Schanz, Daniel; Gesemann, Sebastian; Schröder, Andreas

    2016-05-01

    A Lagrangian tracking method is introduced, which uses a prediction of the particle distribution for the subsequent time-step as a mean to seize the temporal domain. Errors introduced by the prediction process are corrected by an image matching technique (`shaking' the particle in space), followed by an iterative triangulation of particles newly entering the measurement domain. The scheme was termed `Shake-The-Box' and previously characterized as `4D-PTV' due to the strong interaction with the temporal dimension. Trajectories of tracer particles are identified at high spatial accuracy due to a nearly complete suppression of ghost particles; a temporal filtering scheme further improves on accuracy and allows for the extraction of local velocity and acceleration as derivatives of a continuous function. Exploiting the temporal information enables the processing of densely seeded flows (beyond 0.1 particles per pixel, ppp), which were previously reserved for tomographic PIV evaluations. While TOMO-PIV uses statistical means to evaluate the flow (building an `anonymous' voxel space with subsequent spatial averaging of the velocity information using correlation), the Shake-The-Box approach is able to identify and track individual particles at numbers of tens or even hundreds of thousands per time-step. The method is outlined in detail, followed by descriptions of applications to synthetic and experimental data. The synthetic data evaluation reveals that STB is able to capture virtually all true particles, while effectively suppressing the formation of ghost particles. For the examined four-camera set-up particle image densities N I up to 0.125 ppp could be processed. For noise-free images, the attained accuracy is very high. The addition of synthetic noise reduces usable particle image density ( N I ≤ 0.075 ppp for highly noisy images) and accuracy (still being significantly higher compared to tomographic reconstruction). The solutions remain virtually free of ghost

  18. Particle-Tracking Microrheology Using Micro-Optical Coherence Tomography.

    Science.gov (United States)

    Chu, Kengyeh K; Mojahed, Diana; Fernandez, Courtney M; Li, Yao; Liu, Linbo; Wilsterman, Eric J; Diephuis, Bradford; Birket, Susan E; Bowers, Hannah; Martin Solomon, G; Schuster, Benjamin S; Hanes, Justin; Rowe, Steven M; Tearney, Guillermo J

    2016-09-01

    Clinical manifestations of cystic fibrosis (CF) result from an increase in the viscosity of the mucus secreted by epithelial cells that line the airways. Particle-tracking microrheology (PTM) is a widely accepted means of determining the viscoelastic properties of CF mucus, providing an improved understanding of this disease as well as an avenue to assess the efficacies of pharmacologic therapies aimed at decreasing mucus viscosity. Among its advantages, PTM allows the measurement of small volumes, which was recently utilized for an in situ study of CF mucus formed by airway cell cultures. Typically, particle tracks are obtained from fluorescence microscopy video images, although this limits one's ability to distinguish particles by depth in a heterogeneous environment. Here, by performing PTM with high-resolution micro-optical coherence tomography (μOCT), we were able to characterize the viscoelastic properties of mucus, which enables simultaneous measurement of rheology with mucociliary transport parameters that we previously determined using μOCT. We obtained an accurate characterization of dextran solutions and observed a statistically significant difference in the viscosities of mucus secreted by normal and CF human airway cell cultures. We further characterized the effects of noise and imaging parameters on the sensitivity of μOCT-PTM by performing theoretical and numerical analyses, which show that our system can accurately quantify viscosities over the range that is characteristic of CF mucus. As a sensitive rheometry technique that requires very small fluid quantities, μOCT-PTM could also be generally applied to interrogate the viscosity of biological media such as blood or the vitreous humor of the eye in situ. PMID:27602733

  19. Optimization of detector positioning in the radioactive particle tracking technique.

    Science.gov (United States)

    Dubé, Olivier; Dubé, David; Chaouki, Jamal; Bertrand, François

    2014-07-01

    The radioactive particle tracking (RPT) technique is a non-intrusive experimental velocimetry and tomography technique extensively applied to the study of hydrodynamics in a great variety of systems. In this technique, arrays of scintillation detector are used to track the motion of a single radioactive tracer particle emitting isotropic γ-rays. This work describes and applies an optimization strategy developed to find an optimal set of positions for the scintillation detectors used in the RPT technique. This strategy employs the overall resolution of the detectors as the objective function and a mesh adaptive direct search (MADS) algorithm to solve the optimization problem. More precisely, NOMAD, a C++ implementation of the MADS algorithm is used. First, the optimization strategy is validated using simple cases with known optimal detector configurations. Next, it is applied to a three-dimensional axisymmetric system (i.e. a vertical cylinder, which could represent a fluidized bed, bubble column, riser or else). The results obtained using the optimization strategy are in agreement with what was previously recommended by Roy et al. (2002) for a similar system. Finally, the optimization strategy is used for a system consisting of a partially filled cylindrical tumbler. The application of insights gained by the optimization strategy is shown to lead to a significant reduction in the error made when reconstructing the position of a tracer particle. The results of this work show that the optimization strategy developed is sensitive to both the type of objective function used and the experimental conditions. The limitations and drawbacks of the optimization strategy are also discussed.

  20. PEPT: An invaluable tool for 3-D particle tracking and CFD simulation verification in hydrocyclone studies

    Directory of Open Access Journals (Sweden)

    Hoffmann Alex C.

    2013-05-01

    Full Text Available Particle tracks in a hydrocyclone generated both experimentally by positron emission particle tracking (PEPT and numerically with Eulerian-Lagranian CFD have been studied and compared. A hydrocyclone with a cylinder-on-cone design was used in this study, the geometries used in the CFD simulations and in the experiments being identical. It is shown that it is possible to track a fast-moving particle in a hydrocyclone using PEPT with high temporal and spatial resolutions. The numerical 3-D particle trajectories were generated using the Large Eddy Simulation (LES turbulence model for the fluid and Lagrangian particle tracking for the particles. The behaviors of the particles were analyzed in detail and were found to be consistent between experiments and CFD simulations. The tracks of the particles are discussed and related to the fluid flow field visualized in the CFD simulations using the cross-sectional static pressure distribution.

  1. Automated single particle detection and tracking for large microscopy datasets.

    Science.gov (United States)

    Wilson, Rhodri S; Yang, Lei; Dun, Alison; Smyth, Annya M; Duncan, Rory R; Rickman, Colin; Lu, Weiping

    2016-05-01

    Recent advances in optical microscopy have enabled the acquisition of very large datasets from living cells with unprecedented spatial and temporal resolutions. Our ability to process these datasets now plays an essential role in order to understand many biological processes. In this paper, we present an automated particle detection algorithm capable of operating in low signal-to-noise fluorescence microscopy environments and handling large datasets. When combined with our particle linking framework, it can provide hitherto intractable quantitative measurements describing the dynamics of large cohorts of cellular components from organelles to single molecules. We begin with validating the performance of our method on synthetic image data, and then extend the validation to include experiment images with ground truth. Finally, we apply the algorithm to two single-particle-tracking photo-activated localization microscopy biological datasets, acquired from living primary cells with very high temporal rates. Our analysis of the dynamics of very large cohorts of 10 000 s of membrane-associated protein molecules show that they behave as if caged in nanodomains. We show that the robustness and efficiency of our method provides a tool for the examination of single-molecule behaviour with unprecedented spatial detail and high acquisition rates.

  2. 3D measurement of the position of gold particles via evanescent digital holographic particle tracking velocimetry

    Science.gov (United States)

    Satake, Shin-ichi; Unno, Noriyuki; Nakata, Shuichiro; Taniguchi, Jun

    2016-08-01

    A new technique based on digital holography and evanescent waves was developed for 3D measurements of the position of gold nanoparticles in water. In this technique, an intensity profile is taken from a holographic image of a gold particle. To detect the position of the gold particle with high accuracy, its holographic image is recorded on a nanosized step made of MEXFLON, which has a refractive index close to that of water, and the position of the particle is reconstructed by means of digital holography. The height of the nanosized step was measured by using a profilometer and the digitally reconstructed height of the glass substrate had good agreement with the measured value. Furthermore, this method can be used to accurately track the 3D position of a gold particle in water.

  3. Steady-state particle tracking in the object-oriented regional groundwater model ZOOMQ3D

    OpenAIRE

    Jackson, C.R.

    2002-01-01

    This report describes the development of a steady-state particle tracking code for use in conjunction with the object-oriented regional groundwater flow model, ZOOMQ3D (Jackson, 2001). Like the flow model, the particle tracking software, ZOOPT, is written using an object-oriented approach to promote its extensibility and flexibility. ZOOPT enables the definition of steady-state pathlines in three dimensions. Particles can be tracked in both the forward and reverse directions en...

  4. SSCTRK: A particle tracking code for the SSC

    International Nuclear Information System (INIS)

    While many indirect methods are available to evaluate dynamic aperture there appears at this time to be no reliable substitute to tracking particles through realistic machine lattices for a number of turns determined by the storage times. Machine lattices are generated by ''Monte Carlo'' techniques from the expected rms fabrication and survey errors. Any given generated machine can potentially be a lucky or unlucky fluctuation from the average. Therefore simulation to serve as a predictor of future performance must be done for an ensemble of generated machines. Further, several amplitudes and momenta are necessary to predict machine performance. Thus to make Monte Carlo type simulations for the SSC requires very considerable computer resources. Hitherto, it has been assumed that this was not feasible, and alternative indirect methods have been proposed or tried to answer the problem. We reexamined the feasibility of using direct computation. Previous codes have represented lattices by a succession of thin elements separated by bend-drifts. With ''kick-drift'' configurations, tracking time is linear in the multipole order included, and the code is symplectic. Modern vector processors simultaneously handle a large number of cases in parallel. Combining the efficiencies of kick drift tracking with vector processing, in fact, makes realistic Monte Carlo simulation entirely feasible. SSCTRK uses the above features. It is structured to have a very friendly interface, a very wide latitude of choice for cases to be run in parallel, and, by using pure FORTRAN 77, to interchangeably run on a wide variety of computers. We describe in this paper the program structure operational checks and results achieved

  5. Multi-Color Single Particle Tracking with Quantum Dots

    DEFF Research Database (Denmark)

    Christensen, Eva Arnspang; Brewer, J. R.; Lagerholm, B. C.

    2012-01-01

    Quantum dots (QDs) have long promised to revolutionize fluorescence detection to include even applications requiring simultaneous multi-species detection at single molecule sensitivity. Despite the early promise, the unique optical properties of QDs have not yet been fully exploited in e. g....... multiplex single molecule sensitivity applications such as single particle tracking (SPT). In order to fully optimize single molecule multiplex application with QDs, we have in this work performed a comprehensive quantitative investigation of the fluorescence intensities, fluorescence intensity fluctuations...... further show that there is only a small size advantage in using blue-shifted QDs in biological applications because of the additional size of the water-stabilizing surface coat. Extending previous work, we finally also show that parallel four color multicolor (MC)-SPT with QDs is possible at an image...

  6. Robust and Adaptive Block Tracking Method Based on Particle Filter

    Directory of Open Access Journals (Sweden)

    Bin Sun

    2015-10-01

    Full Text Available In the field of video analysis and processing, object tracking is attracting more and more attention especially in traffic management, digital surveillance and so on. However problems such as objects’ abrupt motion, occlusion and complex target structures would bring difficulties to academic study and engineering application. In this paper, a fragmentsbased tracking method using the block relationship coefficient is proposed. In this method, we use particle filter algorithm and object region is divided into blocks initially. The contribution of this method is that object features are not extracted just from a single block, the relationship between current block and its neighbor blocks are extracted to describe the variation of the block. Each block is weighted according to the block relationship coefficient when the block is voted on the most matched region in next frame. This method can make full use of the relationship between blocks. The experimental results demonstrate that our method can provide good performance in condition of occlusion and abrupt posture variation.

  7. Monte Carlo N-Particle Tracking of Ultrafine Particle Flow in Bent Micro-Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Casella, Andrew M.; Loyalka, Sudarsham K.

    2016-02-16

    The problem of large pressure-differential driven laminar convective-diffusive ultrafine aerosol flow through bent micro-tubes is of interest in several contemporary research areas including; release of contents from pressurized containment vessels, aerosol sampling equipment, advanced scientific instruments, gas-phase micro-heat exchangers, and microfluidic devices. In each of these areas, the predominant problem is the determination of the fraction of particles entering the micro-tube that is deposited within the tube and the fraction that is transmitted through. Due to the extensive parameter restrictions of this class of problems, a Lagrangian particle tracking method making use of the coupling of the analytical stream line solutions of Dean and the simplified Langevin equation is quite a useful tool in problem characterization. This method is a direct analog to the Monte Carlo N-Particle method of particle transport extensively used in nuclear physics and engineering. In this work, 10 nm diameter particles with a density of 1 g/cm3 are tracked within micro-tubes with toroidal bends with pressure differentials ranging between 0.2175 and 0.87 atmospheres. The tubes have radii of 25 microns and 50 microns and the radius of curvature is between 1 m and 0.3183 cm. The carrier gas is helium, and temperatures of 298 K and 558 K are considered. Numerical convergence is considered as a function of time step size and of the number of particles per simulation. Particle transmission rates and deposition patterns within the bent micro-tubes are calculated.

  8. Particle image velocimetry for the Surface Tension Driven Convection Experiment using a particle displacement tracking technique

    Science.gov (United States)

    Wernet, Mark P.; Pline, Alexander D.

    1991-01-01

    The Surface Tension Driven Convection Experiment (STDCE) is a Space Transportation System flight experiment to study both transient and steady thermocapillary fluid flows aboard the USML-1 Spacelab mission planned for 1992. One of the components of data collected during the experiment is a video record of the flow field. This qualitative data is then quantified using an all electronic, two-dimensional particle image velocimetry technique called particle displacement tracking (PDT) which uses a simple space domain particle tracking algorithm. The PDT system is successful in producing velocity vector fields from the raw video data. Application of the PDT technique to a sample data set yielded 1606 vectors in 30 seconds of processing time. A bottom viewing optical arrangement is used to image the illuminated plane, which causes keystone distortion in the final recorded image. A coordinate transformation was incorporated into the system software to correct this viewing angle distortion. PDT processing produced 1.8 percent false identifications, due to random particle locations. A highly successful routine for removing the false identifications was also incorporated, reducing the number of false identifications to 0.2 percent.

  9. Study on Multi-Target Tracking Based on Particle Filter Algorithm

    OpenAIRE

    Junying Meng; Jiaomin Liu; Yongzheng Li; Juan Wang

    2013-01-01

    Particle filter is a probability estimation method based on Bayesian framework and it has unique advantage to describe the target tracking non-linear and non-Gaussian. In this study, firstly, analyses the particle degeneracy and sample impoverishment in particle filter multi-target tracking algorithm and secondly, it applies Markov Chain Monte Carlo (MCMC) method to improve re-sampling process and enhance performance of particle filter algorithm.

  10. Using FTK tracks for particle flow reconstruction at the high-level trigger of ATLAS

    CERN Document Server

    Jaeger, Benjamin Paul

    2016-01-01

    The Fast Tracker (FTK) enables the ATLAS high-level trigger (HLT) to have early access to global tracking information. The project of my Summer Student Internship at CERN was to investigate the potential of using particle flow reconstruction with FTK tracks at the ATLAS HLT. This report shortly summarizes my studies, ranging from comparison of FTK tracks with offline tracks to more sophisticated analyses, such as assessing the jet resolution and trigger related properties.

  11. Multi-color single particle tracking with quantum dots.

    Directory of Open Access Journals (Sweden)

    Eva C Arnspang

    Full Text Available Quantum dots (QDs have long promised to revolutionize fluorescence detection to include even applications requiring simultaneous multi-species detection at single molecule sensitivity. Despite the early promise, the unique optical properties of QDs have not yet been fully exploited in e. g. multiplex single molecule sensitivity applications such as single particle tracking (SPT. In order to fully optimize single molecule multiplex application with QDs, we have in this work performed a comprehensive quantitative investigation of the fluorescence intensities, fluorescence intensity fluctuations, and hydrodynamic radii of eight types of commercially available water soluble QDs. In this study, we show that the fluorescence intensity of CdSe core QDs increases as the emission of the QDs shifts towards the red but that hybrid CdSe/CdTe core QDs are less bright than the furthest red-shifted CdSe QDs. We further show that there is only a small size advantage in using blue-shifted QDs in biological applications because of the additional size of the water-stabilizing surface coat. Extending previous work, we finally also show that parallel four color multicolor (MC-SPT with QDs is possible at an image acquisition rate of at least 25 Hz. We demonstrate the technique by measuring the lateral dynamics of a lipid, biotin-cap-DPPE, in the cellular plasma membrane of live cells using four different colors of QDs; QD565, QD605, QD655, and QD705 as labels.

  12. Digital characterization of recoil charged-particle tracks for neutron measurements

    International Nuclear Information System (INIS)

    We are developing a new optical ionization detector for imaging the track of a charged neutron-recoil particle in a gas. Electrons produced in the path of the recoil particle are excited by an external, high-voltage, rf, electric field of short duration. Their oscillatory motion causes ionization and excitation of nearby gas molecules, which then emit light in subsequent de-excitation. Two digital cameras image the optical radiation across two perpendicular planes and analyze it for the numbers of electrons in various volume elements along the track. These numbers constitute the digital characterization of the track. This information can then be used to infer the energy deposited in the track and the track LET in the gas. We have now observed alpha-particle tracks in a chamber utilizing these principles. The application of such a device for neutron dosimetry and neuron spectrometry will be described. (orig.)

  13. CELL TRACKING USING PARTICLE FILTERS WITH IMPLICIT CONVEX SHAPE MODEL IN 4D CONFOCAL MICROSCOPY IMAGES

    Science.gov (United States)

    Ramesh, Nisha; Tasdizen, Tolga

    2016-01-01

    Bayesian frameworks are commonly used in tracking algorithms. An important example is the particle filter, where a stochastic motion model describes the evolution of the state, and the observation model relates the noisy measurements to the state. Particle filters have been used to track the lineage of cells. Propagating the shape model of the cell through the particle filter is beneficial for tracking. We approximate arbitrary shapes of cells with a novel implicit convex function. The importance sampling step of the particle filter is defined using the cost associated with fitting our implicit convex shape model to the observations. Our technique is capable of tracking the lineage of cells for nonmitotic stages. We validate our algorithm by tracking the lineage of retinal and lens cells in zebrafish embryos. PMID:27403085

  14. Particle Tracking Model and Abstraction of Transport Processes

    Energy Technology Data Exchange (ETDEWEB)

    B. Robinson

    2004-10-21

    The purpose of this report is to document the abstraction model being used in total system performance assessment (TSPA) model calculations for radionuclide transport in the unsaturated zone (UZ). The UZ transport abstraction model uses the particle-tracking method that is incorporated into the finite element heat and mass model (FEHM) computer code (Zyvoloski et al. 1997 [DIRS 100615]) to simulate radionuclide transport in the UZ. This report outlines the assumptions, design, and testing of a model for calculating radionuclide transport in the UZ at Yucca Mountain. In addition, methods for determining and inputting transport parameters are outlined for use in the TSPA for license application (LA) analyses. Process-level transport model calculations are documented in another report for the UZ (BSC 2004 [DIRS 164500]). Three-dimensional, dual-permeability flow fields generated to characterize UZ flow (documented by BSC 2004 [DIRS 169861]; DTN: LB03023DSSCP9I.001 [DIRS 163044]) are converted to make them compatible with the FEHM code for use in this abstraction model. This report establishes the numerical method and demonstrates the use of the model that is intended to represent UZ transport in the TSPA-LA. Capability of the UZ barrier for retarding the transport is demonstrated in this report, and by the underlying process model (BSC 2004 [DIRS 164500]). The technical scope, content, and management of this report are described in the planning document ''Technical Work Plan for: Unsaturated Zone Transport Model Report Integration'' (BSC 2004 [DIRS 171282]). Deviations from the technical work plan (TWP) are noted within the text of this report, as appropriate. The latest version of this document is being prepared principally to correct parameter values found to be in error due to transcription errors, changes in source data that were not captured in the report, calculation errors, and errors in interpretation of source data.

  15. Particle Tracking Model and Abstraction of Transport Processes

    International Nuclear Information System (INIS)

    The purpose of this report is to document the abstraction model being used in total system performance assessment (TSPA) model calculations for radionuclide transport in the unsaturated zone (UZ). The UZ transport abstraction model uses the particle-tracking method that is incorporated into the finite element heat and mass model (FEHM) computer code (Zyvoloski et al. 1997 [DIRS 100615]) to simulate radionuclide transport in the UZ. This report outlines the assumptions, design, and testing of a model for calculating radionuclide transport in the UZ at Yucca Mountain. In addition, methods for determining and inputting transport parameters are outlined for use in the TSPA for license application (LA) analyses. Process-level transport model calculations are documented in another report for the UZ (BSC 2004 [DIRS 164500]). Three-dimensional, dual-permeability flow fields generated to characterize UZ flow (documented by BSC 2004 [DIRS 169861]; DTN: LB03023DSSCP9I.001 [DIRS 163044]) are converted to make them compatible with the FEHM code for use in this abstraction model. This report establishes the numerical method and demonstrates the use of the model that is intended to represent UZ transport in the TSPA-LA. Capability of the UZ barrier for retarding the transport is demonstrated in this report, and by the underlying process model (BSC 2004 [DIRS 164500]). The technical scope, content, and management of this report are described in the planning document ''Technical Work Plan for: Unsaturated Zone Transport Model Report Integration'' (BSC 2004 [DIRS 171282]). Deviations from the technical work plan (TWP) are noted within the text of this report, as appropriate. The latest version of this document is being prepared principally to correct parameter values found to be in error due to transcription errors, changes in source data that were not captured in the report, calculation errors, and errors in interpretation of source data

  16. Tracking parameter simulation for the Turkish accelerator center particle factory tracker system

    Science.gov (United States)

    Tapan, I.; Pilicer, E.; Pilicer, F. B.

    2016-09-01

    The silicon tracker part of the Turkish Accelerator Center super charm particle factory detector was designed for effectively tracking charged particles with momentum values up to 2.0 GeV/c. In this work, the FLUKA simulation code has been used to estimate the track parameters and their resolutions in the designed tracker system. These results have been compared with those obtained by the tkLayout software package. The simulated track parameter resolutions are compatible with the physics goals of the tracking detector.

  17. Track before detect for point targets with particle filter in infrared image sequences

    Institute of Scientific and Technical Information of China (English)

    Hongtao Hu; Zhongliang Jing; Shiqiang Hu

    2005-01-01

    @@ The problem of detecting and tracking point targets in a sequence of infrared images with very low signalto-noise ratio (SNR) is investigated in this paper. A track before detect algorithm for infrared (IR) point target is developed based on particle filter. The particle filter is used to estimate the state of the target in track stage. The unnormalized weights of the output of the filter are used to approximately construct the likelihood ratio for hypothesis test in detection stage. Experiment results with the real image sequences that SNR is about 2.0 show that the proposed algorithm can successfully detect and track point target.

  18. 3D particle tracking velocimetry using dynamic discrete tomography for plasma physics applications

    DEFF Research Database (Denmark)

    Moseev, Dmitry; Alpers, Andreas; Gritzmann, Peter;

    2013-01-01

    3D particle tracking velocimetry (PTV) is a diagnostic technique which is widely used for studying flows, combustion, and plasmas. Current tomographic particle tracking methods are based on the multiplicative algebraic reconstruction technique and used for reconstructing the distribution of multi......-pixel sized particles as greylevel images. Reconstructions obtained by these methods do not necessarily match the experimental data. We propose a new algorithm which can be used for tracking dust particles in tokamaks and stellarators, as well as in low-temperature and complex plasmas. The dynamic discrete...... tomography algorithm is efficient for data from two projection directions and exact. The non-uniqueness can be detected and tracked individually. The algorithm performance is proportional to N3 on average where N is the number of particles in the reconstruction. There is a room for further improvement...

  19. An efficient Rao-Blackwellized particle filter for object tracking

    OpenAIRE

    Arnaud, Elise; Memin, Etienne

    2005-01-01

    International audience In this paper we present a technique for the tracking of textured almost planar object. The target is modeled as a noisy planar cloud of points. The tracking is led with an appropriate non linear stochastic filter. The particular system that we devised is conditionally Gaussian and can be efficiently implemented through variance reduction principle known as Rao-Blackwellisation. Our model allows also to melt a correlation measurements with dynamic model estimated fro...

  20. A particle-filtering approach to convoy tracking in the midst of civilian traffic

    Science.gov (United States)

    Pollard, Evangeline; Pannetier, Benjamin; Rombaut, Michèle

    2008-04-01

    In the battlefield surveillance domain, ground target tracking is used to evaluate the threat. Data used for tracking is given by a Ground Moving Target Indicator (GMTI) sensor which only detects moving targets. Multiple target tracking has been widely studied but most of the algorithms have weaknesses when targets are close together, as they are in a convoy. In this work, we propose a filtering approach for convoys in the midst of civilian traffic. Inspired by particle filtering, our specific algorithm cannot be applied to all the targets because of its complexity. That is why well discriminated targets are tracked using an Interacting Multiple Model-Multiple Hypothesis Tracking (IMM-MHT), whereas the convoy targets are tracked with a specific particle filter. We make the assumption that the convoy is detected (position and number of targets). Our approach is based on an Independent Partition Particle Filter (IPPF) incorporating constraint-regions. The originality of our approach is to consider a velocity constraint (all the vehicles belonging to the convoy have the same velocity) and a group constraint. Consequently, the multitarget state vector contains all the positions of the individual targets and a single convoy velocity vector. When another target is detected crossing or overtaking the convoy, a specific algorithm is used and the non-cooperative target is tracked down an adapted particle filter. As demonstrated by our simulations, a high increase in convoy tracking performance is obtained with our approach.

  1. Compositional asynchronous membrane systems

    Institute of Scientific and Technical Information of China (English)

    Cosmin Bonchis; Cornel Izbasa; Gabriel Ciobanu

    2007-01-01

    This paper presents an algorithmic way of building complex membrane systems by coupling elementary membranes. Its application seems particularly valuable in the case of asynchronous membrane systems, since the resulting membrane system remains asynchronous. The composition method is based on a handshake mechanism implemented by using antiport rules and promoters.

  2. A SUNTANS-based unstructured grid local exact particle tracking model

    Science.gov (United States)

    Liu, Guangliang; Chua, Vivien P.

    2016-07-01

    A parallel particle tracking model, which employs the local exact integration method to achieve high accuracy, has been developed and embedded in an unstructured-grid coastal ocean model, Stanford Unstructured Nonhydrostatic Terrain-following Adaptive Navier-Stokes Simulator (SUNTANS). The particle tracking model is verified and compared with traditional numerical integration methods, such as Runge-Kutta fourth-order methods using several test cases. In two-dimensional linear steady rotating flow, the local exact particle tracking model is able to track particles along the circular streamline accurately, while Runge-Kutta fourth-order methods produce trajectories that deviate from the streamlines. In periodically varying double-gyre flow, the trajectories produced by local exact particle tracking model with time step of 1.0 × 10- 2 s are similar to those trajectories obtained from the numerical integration methods with reduced time steps of 1.0 × 10- 4 s. In three-dimensional steady Arnold-Beltrami-Childress (ABC) flow, the trajectories integrated with the local exact particle tracking model compares well with the approximated true path. The trajectories spiral upward and their projection on the x- y plane is a periodic ellipse. The trajectories derived with the Runge-Kutta fourth-order method deviate from the approximated true path, and their projections on the x- y plane are unclosed ellipses with growing long and short axes. The spatial temporal resolution needs to be carefully chosen before particle tracking models are applied. Our results show that the developed local exact particle tracking model is accurate and suitable for marine Lagrangian (trajectory-based)-related research.

  3. Multiple Human Tracking Using Particle Filter with Gaussian Process Dynamical Model

    OpenAIRE

    Hong Man; Yafeng Yin; Jing Wang

    2008-01-01

    Abstract We present a particle filter-based multitarget tracking method incorporating Gaussian process dynamical model (GPDM) to improve robustness in multitarget tracking. With the particle filter Gaussian process dynamical model (PFGPDM), a high-dimensional target trajectory dataset of the observation space is projected to a low-dimensional latent space in a nonlinear probabilistic manner, which will then be used to classify object trajectories, predict the next motion state, and provide Ga...

  4. A Symplectic Multi-Particle Tracking Model for Self-Consistent Space-Charge Simulation

    CERN Document Server

    Qiang, Ji

    2016-01-01

    Symplectic tracking is important in accelerator beam dynamics simulation. So far, to the best of our knowledge, there is no self-consistent symplectic space-charge tracking model available in the accelerator community. In this paper, we present a two-dimensional and a three-dimensional symplectic multi-particle spectral model for space-charge tracking simulation. This model includes both the effect from external fields and the effect of self-consistent space-charge fields using a split-operator method. Such a model preserves the phase space structure and shows much less numerical emittance growth than the particle-in-cell model in the illustrative examples.

  5. Using Gaussian Process Annealing Particle Filter for 3D Human Tracking

    Directory of Open Access Journals (Sweden)

    Michael Rudzsky

    2008-01-01

    Full Text Available We present an approach for human body parts tracking in 3D with prelearned motion models using multiple cameras. Gaussian process annealing particle filter is proposed for tracking in order to reduce the dimensionality of the problem and to increase the tracker's stability and robustness. Comparing with a regular annealed particle filter-based tracker, we show that our algorithm can track better for low frame rate videos. We also show that our algorithm is capable of recovering after a temporal target loss.

  6. Tracking with particle filter for high-dimensional observation and state spaces

    CERN Document Server

    Dubuisson, Séverine

    2015-01-01

    This title concerns the use of a particle filter framework to track objects defined in high-dimensional state-spaces using high-dimensional observation spaces.  Current tracking applications require us to consider complex models for objects (articulated objects, multiple objects, multiple fragments, etc.) as well as multiple kinds of information (multiple cameras, multiple modalities, etc.). This book presents some recent research that considers the main bottleneck of particle filtering frameworks (high dimensional state spaces) for tracking in such difficult conditions.

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

    Science.gov (United States)

    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.

  8. Particle track reconstruction in heavy materials with the Kalman technique

    International Nuclear Information System (INIS)

    The relatively recent use in HEP of the Kalman filtering and smoothing technique for the reconstruction of single tracks through gaseous detectors interspaced by heavy materials, is shown to work and to give even better results than other more classic techniques. However, fine tuning of the computer implementation has to be done carefully as well as respecting the mathematical constraints. The feasibility of the Kalman method in heavy materials here demonstrated may lead to the development of a general software package for the reconstruction of single tracks in HEP detectors. (orig.)

  9. Improvement in Fast Particle Track Reconstruction with Robust Statistics

    CERN Document Server

    Aartsen, M G; 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; Tjus, J Becker; 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; Silva, A H Cruz; 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; Ismail, A Haj; 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; Heros, C Pérez de los; 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; Stanisha, N A; 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

    2013-01-01

    The IceCube project has transformed one cubic kilometer of deep natural Antarctic ice into a Cherenkov detector. Muon neutrinos are detected and their direction 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 manuscript 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 detectors early reconstruction with dat...

  10. Aerogel Track Morphology: Measurement, Three Dimensional Reconstruction and Particle Location using Confocal Laser Scanning Microscopy

    Science.gov (United States)

    Kearsley, A. T.; Ball, A. D.; Wozniakiewicz, P. A.; Graham, G. A.; Burchell, M. J.; Cole, M. J.; Horz, F.; See, T. H.

    2007-01-01

    The Stardust spacecraft returned the first undoubted samples of cometary dust, with many grains embedded in the silica aerogel collector . Although many tracks contain one or more large terminal particles of a wide range of mineral compositions , there is also abundant material along the track walls. To help interpret the full particle size, structure and mass, both experimental simulation of impact by shots and numerical modeling of the impact process have been attempted. However, all approaches require accurate and precise measurement of impact track size parameters such as length, width and volume of specific portions. To make such measurements is not easy, especially if extensive aerogel fracturing and discoloration has occurred. In this paper we describe the application and limitations of laser confocal imagery for determination of aerogel track parameters, and for the location of particle remains.

  11. Fast Visual Object Tracking Using Modified kalman and Particle Filtering Algorithms in the Presence of Occlusions

    Directory of Open Access Journals (Sweden)

    G.Mallikarjuna Rao

    2014-09-01

    Full Text Available In the present day real time applications of visual object tracking in surveillance, it has become extremely complex, time consuming and tricky to do the tracking when there are occlusions are present for small duration or for longer time and also when it is done in outdoor environments. In these conditions, the target to be tracked can be lost for few seconds and that should be tracked as soon as possible. As from the literature it is observed that particle filter can be able to track the target robustly in different kinds of background conditions, and it’s robust to partial occlusion. However, this tracking cannot recover from large proportion of occlusion and complete occlusion, to avoid this condition, we proposed two new algorithms (modified kalman and modified particle filter for fast tracking of objects in the presence of occlusions. We considered the complete occlusion of tracking object and the main objective is how fast the system is able to track the object after the occlusion is crossed. From the experimental results, it is observed that the proposed algorithms have shown good improvement in results compared to the traditional methods.

  12. Tracking Particles in Flows near Invariant Manifolds via Balance Functions

    CERN Document Server

    Kuehn, Christian; Kuhlmann, Hendrik C

    2016-01-01

    Particles moving inside a fluid near, and interacting with, invariant manifolds is a common phenomenon in a wide variety of applications. One elementary question is whether we can determine once a particle has entered a neighbourhood of an invariant manifold, when it leaves again. Here we approach this problem mathematically by introducing balance functions, which relate the entry and exit points of a particle by an integral variational formula. We define, study, and compare different natural choices for balance functions and conclude that an efficient compromise is to employ normal infinitesimal Lyapunov exponents. We apply our results to two different model flows: a regularized solid-body rotational flow and the asymmetric Kuhlmann--Muldoon model developed in the context of liquid bridges. Furthermore, we employ full numerical simulations of the Navier-Stokes equations of a two-way coupled particle in a shear--stress-driven cavity to test balance functions for a particle moving near an invariant wall. In co...

  13. Visible light photon counters (VLPCs) for high rate tracking medical imaging and particle astrophysics

    International Nuclear Information System (INIS)

    This paper is on the operation principles of the Visible Light Photon Counters (VLPCs), application to high luminosity-high multiplicity tracking for High Energy Charged Particle Physics, and application to Medical Imaging and Particle Astrophysics. The VLPCs as Solid State Photomultipliers (SSPMS) with high quantum efficiency can detect down to single photons very efficiently with excellent time resolution and high avalanche gains

  14. Visible light photon counters (VLPCs) for high rate tracking medical imaging and particle astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Atac, M.

    1998-02-01

    This paper is on the operation principles of the Visible Light Photon Counters (VLPCs), application to high luminosity-high multiplicity tracking for High Energy Charged Particle Physics, and application to Medical Imaging and Particle Astrophysics. The VLPCs as Solid State Photomultipliers (SSPMS) with high quantum efficiency can detect down to single photons very efficiently with excellent time resolution and high avalanche gains.

  15. Lagrangian particle tracking in three dimensions via single-camera in-line digital holography

    Energy Technology Data Exchange (ETDEWEB)

    Lu Jiang; Fugal, Jacob P; Nordsiek, Hansen; Saw, Ewe Wei; Shaw, Raymond A; Yang Weidong [Department of Physics, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA International Collaboration for Turbulence Research (United States)], E-mail: rashaw@mtu.edu

    2008-12-15

    Lagrangian particle trajectories are measured in three spatial dimensions with a single camera using the method of digital in-line holography. Lagrangian trajectories of 60-120 {mu}m diameter droplets in turbulent air obtained with data from one camera compare favorably with tracks obtained from a simultaneous dual-camera data set, the latter having high spatial resolution in all three dimensions. Using the single-camera system, particle motion along the optical axis is successfully tracked, allowing for long, continuous 3D tracks, but the depth resolution based on standard reconstruction methods is not sufficient to obtain accurate acceleration measurements for that component. Lagrangian velocity distributions for all three spatial components agree within reasonable sampling uncertainties and Lagrangian acceleration distributions agree for the two lateral components. An equivalent single-camera, imaging-based 2D tracking system would be challenged by the particle densities tested, but the holographic configuration allows for 3D tracking in the dilute limit. The method also allows particle size, shape and orientation to be measured along the trajectory. Lagrangian measurements of particle size provide a direct measure of particle size uncertainty under realistic conditions sampled from the entire measurement volume.

  16. Comparison of particle tracks calculated by Monte Carlo computer codes with experimental tracks observed with the Harwell low pressure cloud chamber

    International Nuclear Information System (INIS)

    Photographs of the droplets associated with the ionisations caused by charged particle tracks in the Harwell low pressure cloud chamber have been analysed. The radiation types these represent are alpha particles, protons and low energy X rays (carbon and aluminium) in either a tissue-equivalent gas or water vapour. The tracks were used to test the validity of two Monte Carlo codes developed by Wilson and Paratzke, namely MOCA14 for the generation of proton and alpha particle tracks, and MOCA8 for the generation of electron tracks. The comparisons showed that the code MOCA14 would appear to be valid for protons with energies greater than about 390 keV, and for alpha particles with energies greater than 1.6 MeV. No disagreement was found between the low energy X ray tracks from the cloud chamber and the tracks calculated from MOCA8, although this comparison was severely limited by droplet diffusion. (author)

  17. Recent improvements to the ASTRA particle tracking code

    Energy Technology Data Exchange (ETDEWEB)

    Flottmann, Klaus; Lidia, Steven; Piot, Philippe

    2003-05-19

    The Astra simulation code has been successfully used in the design of linac and rf photoinjector systems utilizing beams with azimuthal symmetry. We present recently implemented changes to Astra that allow tracking of beams in beamlines without the assumption of any symmetry. The changes especially include a 3D mesh space charge algorithm and the possibility to import 3D electromagnetic fieldmaps from eigensolver programs.

  18. Improved estimation of anomalous diffusion exponents in single particle tracking experiments

    OpenAIRE

    Bronshtein, Eldad Kepten Irena; Garini, Yuval

    2012-01-01

    The Mean Square Displacement is a central tool in the analysis of Single Particle Tracking experiments, shedding light on various biophysical phenomena. Frequently, parameters are extracted by performing time-averages on single particle trajectories followed by ensemble averaging. This procedure however, suffers from two systematic errors when applied to particles that perform anomalous diffusion. The first is significant at short time lags and is induced by measurement errors. The second ari...

  19. Orbital single particle tracking on a commercial confocal microscope using piezoelectric stage feedback

    International Nuclear Information System (INIS)

    Single Particle Tracking (SPT) is a technique used to locate fluorescent particles with nanometer precision. In the orbital tracking method the position of a particle is obtained analyzing the distribution of intensity along a circular orbit scanned around the particle. In combination with an active feedback this method allows tracking of particles in 2D and 3D with millisecond temporal resolution. Here we describe a SPT setup based on a feedback approach implemented with minimal modification of a commercially available confocal laser scanning microscope, the Zeiss LSM 510, in combination with an external piezoelectric stage scanner. The commercial microscope offers the advantage of a user-friendly software interface and pre-calibrated hardware components. The use of an external piezo-scanner allows the addition of feedback into the system but also represents a limitation in terms of its mechanical response. We describe in detail this implementation of the orbital tracking method and discuss advantages and limitations. As an example of application to live cell experiments we perform the 3D tracking of acidic vesicles in live polarized epithelial cells. (paper)

  20. Local characterization of hindered Brownian motion by using digital video microscopy and 3D particle tracking

    International Nuclear Information System (INIS)

    In this article we present methods for measuring hindered Brownian motion in the confinement of complex 3D geometries using digital video microscopy. Here we discuss essential features of automated 3D particle tracking as well as diffusion data analysis. By introducing local mean squared displacement-vs-time curves, we are able to simultaneously measure the spatial dependence of diffusion coefficients, tracking accuracies and drift velocities. Such local measurements allow a more detailed and appropriate description of strongly heterogeneous systems as opposed to global measurements. Finite size effects of the tracking region on measuring mean squared displacements are also discussed. The use of these methods was crucial for the measurement of the diffusive behavior of spherical polystyrene particles (505 nm diameter) in a microfluidic chip. The particles explored an array of parallel channels with different cross sections as well as the bulk reservoirs. For this experiment we present the measurement of local tracking accuracies in all three axial directions as well as the diffusivity parallel to the channel axis while we observed no significant flow but purely Brownian motion. Finally, the presented algorithm is suitable also for tracking of fluorescently labeled particles and particles driven by an external force, e.g., electrokinetic or dielectrophoretic forces

  1. Particle tracking during Ostwald ripening using time-resolved laboratory X-ray microtomography

    International Nuclear Information System (INIS)

    Laboratory X-ray microtomography is investigated as a method for obtaining time-resolved images of microstructural coarsening of the semisolid state of Al–5 wt.% Cu samples during Ostwald ripening. Owing to the 3D imaging capability of tomography, this technique uniquely provides access to the growth rates of individual particles, thereby not only allowing a statistical characterization of coarsening—as has long been possible by conventional metallography—but also enabling quantification of the influence of local environment on particle boundary migration. The latter information is crucial to understanding growth kinetics during Ostwald ripening at high volume fractions of the coarsening phase. Automated image processing and segmentation routines were developed to close gaps in the network of particle boundaries and to track individual particles from one annealing step to the next. The particle tracking success rate places an upper bound of only a few percent on the likelihood of segmentation errors for any given particle. The accuracy of particle size trajectories extracted from the time-resolved tomographic reconstructions is correspondingly high. Statistically averaged coarsening data and individual particle growth rates are in excellent agreement with the results of prior experimental studies and with computer simulations of Ostwald ripening. - Highlights: • Ostwald ripening in Al–5 wt.% Cu measured by laboratory X-ray microtomography • Time-resolved measurement of individual particle growth • Automated segmentation routines developed to close gaps in particle boundary network • Particle growth/shrinkage rates deviate from LSW model prediction

  2. Particle tracking during Ostwald ripening using time-resolved laboratory X-ray microtomography

    Energy Technology Data Exchange (ETDEWEB)

    Werz, T., E-mail: thomas.werz@uni-ulm.de [Ulm University, Institute of Micro and Nanomaterials, Albert-Einstein-Allee 47, 89081 (Germany); Baumann, M. [Ulm University, Institute of Micro and Nanomaterials, Albert-Einstein-Allee 47, 89081 (Germany); Wolfram, U. [Ulm University, Institute of Orthopaedic Research and Biomechanics, Helmholtzstrasse 14, 89081 (Germany); Krill, C.E. [Ulm University, Institute of Micro and Nanomaterials, Albert-Einstein-Allee 47, 89081 (Germany)

    2014-04-01

    Laboratory X-ray microtomography is investigated as a method for obtaining time-resolved images of microstructural coarsening of the semisolid state of Al–5 wt.% Cu samples during Ostwald ripening. Owing to the 3D imaging capability of tomography, this technique uniquely provides access to the growth rates of individual particles, thereby not only allowing a statistical characterization of coarsening—as has long been possible by conventional metallography—but also enabling quantification of the influence of local environment on particle boundary migration. The latter information is crucial to understanding growth kinetics during Ostwald ripening at high volume fractions of the coarsening phase. Automated image processing and segmentation routines were developed to close gaps in the network of particle boundaries and to track individual particles from one annealing step to the next. The particle tracking success rate places an upper bound of only a few percent on the likelihood of segmentation errors for any given particle. The accuracy of particle size trajectories extracted from the time-resolved tomographic reconstructions is correspondingly high. Statistically averaged coarsening data and individual particle growth rates are in excellent agreement with the results of prior experimental studies and with computer simulations of Ostwald ripening. - Highlights: • Ostwald ripening in Al–5 wt.% Cu measured by laboratory X-ray microtomography • Time-resolved measurement of individual particle growth • Automated segmentation routines developed to close gaps in particle boundary network • Particle growth/shrinkage rates deviate from LSW model prediction.

  3. Solar Flare Track Exposure Ages in Regolith Particles: A Calibration for Transmission Electron Microscope Measurements

    Science.gov (United States)

    Berger, Eve L.; Keller, Lindsay P.

    2015-01-01

    Mineral grains in lunar and asteroidal regolith samples provide a unique record of their interaction with the space environment. Space weathering effects result from multiple processes including: exposure to the solar wind, which results in ion damage and implantation effects that are preserved in the rims of grains (typically the outermost 100 nm); cosmic ray and solar flare activity, which result in track formation; and impact processes that result in the accumulation of vapor-deposited elements, impact melts and adhering grains on particle surfaces. Determining the rate at which these effects accumulate in the grains during their space exposure is critical to studies of the surface evolution of airless bodies. Solar flare energetic particles (mainly Fe-group nuclei) have a penetration depth of a few millimeters and leave a trail of ionization damage in insulating materials that is readily observable by transmission electron microscope (TEM) imaging. The density of solar flare particle tracks is used to infer the length of time an object was at or near the regolith surface (i.e., its exposure age). Track measurements by TEM methods are routine, yet track production rate calibrations have only been determined using chemical etching techniques [e.g., 1, and references therein]. We used focused ion beam-scanning electron microscope (FIB-SEM) sample preparation techniques combined with TEM imaging to determine the track density/exposure age relations for lunar rock 64455. The 64455 sample was used earlier by [2] to determine a track production rate by chemical etching of tracks in anorthite. Here, we show that combined FIB/TEM techniques provide a more accurate determination of a track production rate and also allow us to extend the calibration to solar flare tracks in olivine.

  4. Analytical Benchmarking, Precision Particle Tracking, Electric and Magnetic Storage Rings, Runge-Kutta, Predictor-Corrector

    CERN Document Server

    Metodiev, E M; Fandaros, M; Haciomeroglu, S; Huang, D; Huang, K L; Patil, A; Prodromou, R; Semertzidis, O A; Sharma, D; Stamatakis, A N; Orlov, Y F; Semertzidis, Y K

    2015-01-01

    A set of analytical benchmarks for tracking programs are required for precision storage ring experiments. To determine the accuracy of precision tracking programs in electric and magnetic rings, a variety of analytical estimates of particle and spin dynamics in the rings are developed and compared to the numerical results of tracking simulations. Initial discrepancies in the comparisons indicated the need for improvement of several of the analytical estimates. As an example, we find that the fourth order Runge-Kutta/Predictor-Corrector method was accurate but slow, and that it passed all the benchmarks it was tested against, often to the sub-part per billion level. Thus high precision analytical estimates and tracking programs based on fourth order Runge-Kutta/Predictor-Corrector integration can be used to benchmark faster tracking programs for accuracy.

  5. Particle track analysis of natural decay series nuclides in sediments and pore waters

    International Nuclear Information System (INIS)

    Solid-state nuclear track detectors sensitive to alpha or fission product particles have been used, with some success, to measure low activities of natural decay series nuclides in environmental samples. Applications assessed thus far include excess 230Th and 210Pb dating of sediments, determination of uranium in sediment matrices and pore waters and dissolved 222Rn assay of aqueous solutions. Whenever possible, data obtained by the particle track methods have been compared with the results of conventional radiochemical analyses on duplicate samples. The observed agreement, although illustrating some limitations of particle track techniques, suggests that they have considerable potential in environmental radiochemistry. Not only are the techniques less skilled, less expensive and more portable than coventional methodology, but also they are generally non-destructive, require much less sample, register very low background levels and are, in some cases, more sensitive. (author)

  6. Analytical benchmarks for precision particle tracking in electric and magnetic rings

    Energy Technology Data Exchange (ETDEWEB)

    Metodiev, E.M. [Brookhaven National Laboratory, Physics Department, Upton, NY 11973 (United States); Harvard College, Harvard University, Cambridge, MA 02138 (United States); Center for Axion and Precision Physics Research, IBS, Daejeon 305-701 (Korea, Republic of); Department of Physics, KAIST, Daejeon 305-701 (Korea, Republic of); D' Silva, I.M.; Fandaros, M. [Brookhaven National Laboratory, Physics Department, Upton, NY 11973 (United States); Gaisser, M. [Center for Axion and Precision Physics Research, IBS, Daejeon 305-701 (Korea, Republic of); Department of Physics, KAIST, Daejeon 305-701 (Korea, Republic of); Hacıömeroğlu, S. [Brookhaven National Laboratory, Physics Department, Upton, NY 11973 (United States); Center for Axion and Precision Physics Research, IBS, Daejeon 305-701 (Korea, Republic of); Istanbul Technical University, Istanbul 34469 (Turkey); Department of Physics, KAIST, Daejeon 305-701 (Korea, Republic of); Huang, D. [Brookhaven National Laboratory, Physics Department, Upton, NY 11973 (United States); Huang, K.L. [Brookhaven National Laboratory, Physics Department, Upton, NY 11973 (United States); Harvard College, Harvard University, Cambridge, MA 02138 (United States); Patil, A.; Prodromou, R.; Semertzidis, O.A.; Sharma, D.; Stamatakis, A.N. [Brookhaven National Laboratory, Physics Department, Upton, NY 11973 (United States); Orlov, Y.F. [Department of Physics, Cornell University, Ithaca, NY (United States); Semertzidis, Y.K. [Brookhaven National Laboratory, Physics Department, Upton, NY 11973 (United States); Center for Axion and Precision Physics Research, IBS, Daejeon 305-701 (Korea, Republic of); Department of Physics, KAIST, Daejeon 305-701 (Korea, Republic of)

    2015-10-11

    To determine the accuracy of tracking programs for precision storage ring experiments, analytical estimates of particle and spin dynamics in electric and magnetic rings were developed and compared to the numerical results of a tracking program based on Runge–Kutta/Predictor–Corrector integration. Initial discrepancies in the comparisons indicated the need to improve several of the analytical estimates. In the end, this rather slow program passed all benchmarks, often agreeing with the analytical estimates to the part-per-billion level. Thus, it can in turn be used to benchmark faster tracking programs for accuracy.

  7. Video object tracking using improved chamfer matching and condensation particle filter

    Science.gov (United States)

    Wu, Tao; Ding, Xiaoqing; Wang, Shengjin; Wang, Kongqiao

    2008-02-01

    Object tracking is an essential problem in the field of video and image processing. Although tracking algorithms working on gray video are convenient in actual applications, they are more difficult to be developed than those using color features, since less information is taken into account. Few researches have been dedicated to tracking object using edge information. In this paper, we proposed a novel video tracking algorithm based on edge information for gray videos. This method adopts the combination of a condensation particle filter and an improved chamfer matching. The improved chamfer matching is rotation invariant and capable of estimating the shift between an observed image patch and a template by an orientation distance transform. A modified discriminative likelihood measurement method that focuses on the difference is adopted. These values are normalized and used as the weights of particles which predict and track the object. Experiment results show that our modifications to chamfer matching improve its performance in video tracking problem. And the algorithm is stable, robust, and can effectively handle rotation distortion. Further work can be done on updating the template to adapt to significant viewpoint and scale changes of the appearance of the object during the tracking process.

  8. Markerless human motion tracking using hierarchical multi-swarm cooperative particle swarm optimization.

    Directory of Open Access Journals (Sweden)

    Sanjay Saini

    Full Text Available The high-dimensional search space involved in markerless full-body articulated human motion tracking from multiple-views video sequences has led to a number of solutions based on metaheuristics, the most recent form of which is Particle Swarm Optimization (PSO. However, the classical PSO suffers from premature convergence and it is trapped easily into local optima, significantly affecting the tracking accuracy. To overcome these drawbacks, we have developed a method for the problem based on Hierarchical Multi-Swarm Cooperative Particle Swarm Optimization (H-MCPSO. The tracking problem is formulated as a non-linear 34-dimensional function optimization problem where the fitness function quantifies the difference between the observed image and a projection of the model configuration. Both the silhouette and edge likelihoods are used in the fitness function. Experiments using Brown and HumanEva-II dataset demonstrated that H-MCPSO performance is better than two leading alternative approaches-Annealed Particle Filter (APF and Hierarchical Particle Swarm Optimization (HPSO. Further, the proposed tracking method is capable of automatic initialization and self-recovery from temporary tracking failures. Comprehensive experimental results are presented to support the claims.

  9. Charged particle tracking at Titan, and further applications

    Science.gov (United States)

    Bebesi, Zsofia; Erdos, Geza; Szego, Karoly

    2016-04-01

    We use the CAPS ion data of Cassini to investigate the dynamics and origin of Titan's atmospheric ions. We developed a 4th order Runge-Kutta method to calculate particle trajectories in a time reversed scenario. The test particle magnetic field environment imitates the curved magnetic environment in the vicinity of Titan. The minimum variance directions along the S/C trajectory have been calculated for all available Titan flybys, and we assumed a homogeneous field that is perpendicular to the minimum variance direction. Using this method the magnetic field lines have been calculated along the flyby orbits so we could select those observational intervals when Cassini and the upper atmosphere of Titan were magnetically connected. We have also taken the Kronian magnetodisc into consideration, and used different upstream magnetic field approximations depending on whether Titan was located inside of the magnetodisc current sheet, or in the lobe regions. We also discuss the code's applicability to comets.

  10. Spin resonance strength calculation through single particle tracking for RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Dutheil, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ranjbar, V. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-05-03

    The strengths of spin resonances for the polarized-proton operation in the Relativistic Heavy Ion Collider are currently calculated with the code DEPOL, which numerically integrates through the ring based on an analytical approximate formula. In this article, we test a new way to calculate the spin resonance strengths by performing Fourier transformation to the actual transverse magnetic fields seen by a single particle traveling through the ring. Comparison of calculated spin resonance strengths is made between this method and DEPOL.

  11. MOTION OF TRACER PARTICLES IN A CENTRIFUGAL PUMP AND ITS TRACKING CHARACTERISTICS

    Institute of Scientific and Technical Information of China (English)

    LI Ya-lin; YUAN Shou-qi; TANG Yue; YUAN Jian-ping

    2012-01-01

    The Basset-Boussinesq-Oseen (BBO) equation can be used for most flows to trace the motion of a particle,but in a centrifugal pump,among the forces that act on the particles,one should also include those due to the impeller rotation,as additional effects.This paper firstly reviews various approximations of the BBO equation for the motion of dispersion particles in a viscous fluid.Then based on the motion equation for particles in low Reynolds number centrifugal pumps,a formula for calculating the tracking characteristics of tracer particles is deduced through the Fourier integral transformation.After that the deviations of the particle motion from the fluid motion,as predicted by the various approximations,are discussed and compared.At last,with an emphasis on the Particle Image Velocimetry (PIV) results,the tracking characteristics of particles are estimated.Also,advantages and disadvantages of different tracer particles are discussed and suitable tracer particles for application in PIV studies for flow fields in centrifugal pumps are suggested.

  12. Alpha particles energy estimation from track diameter development in a CR-39 detector.

    Science.gov (United States)

    Azooz, Aassim A; Al-Jubbori, Mushtaq A

    2016-09-01

    The slight nonlinearity in temporal development of tracks diameter in CR-39 nuclear track detectors is examined with the aim of attempting to find if such nonlinearity can be directly related to the charged particle energy. Narrowly spaced etching time-diameter experimental data for alpha particles at five energy values and for one additional energy value etched at five different temperatures are obtained. Initial results show good indication that measuring such time-diameter relationship can form a useful energy estimation tool. Good consistency with other independent published results is obtained. PMID:27341133

  13. Alpha particles energy estimation from track diameter development in a CR-39 detector.

    Science.gov (United States)

    Azooz, Aassim A; Al-Jubbori, Mushtaq A

    2016-09-01

    The slight nonlinearity in temporal development of tracks diameter in CR-39 nuclear track detectors is examined with the aim of attempting to find if such nonlinearity can be directly related to the charged particle energy. Narrowly spaced etching time-diameter experimental data for alpha particles at five energy values and for one additional energy value etched at five different temperatures are obtained. Initial results show good indication that measuring such time-diameter relationship can form a useful energy estimation tool. Good consistency with other independent published results is obtained.

  14. Experimental validation of granular dynamics simulations of gas-fluidised beds with homogeneous inflow conditions using Positron Emission Particle Tracking

    NARCIS (Netherlands)

    Hoomans, B.P.B.; Kuipers, J.A.M.; Mohd Salleh, M.; Seville, J.P.

    2001-01-01

    A hard-sphere granular dynamics model of a two-dimensional gas-fluidised bed was experimentally validated using Positron Emission Particle Tracking (PEPT). In the model the Newtonian equations of motion are solved for each solid particle while taking into account the particle¿particle and particle¿w

  15. Three-dimensional textural and compositional analysis of particle tracks and fragmentation history in aerogel

    Energy Technology Data Exchange (ETDEWEB)

    Ebel, Denton S.; Greenberg, Michael; Rivers, Mark L.; Newville, Matthew; (AMNH)

    2010-05-04

    We report analyses of aerogel tracks using (1) synchrotron X-ray computed microtomography (XRCMT), (2) laser confocal scanning microscopy (LCSM), and (3) synchrotron radiation X-ray fluorescence (SRXRF) of particles and their paths resulting from simulated hypervelocity impacts (1-2), and a single {approx}1 mm aerogel track from the Stardust cometary sample collector (1-3). Large aerogel pieces can be imaged sequentially, resulting in high spatial resolution images spanning many tomographic fields of view ('lambda-tomography'). We report calculations of energy deposited, and tests on aromatic hydrocarbons showing no alteration in tomography experiments. Imaging at resolutions from -17 to -1 micron/pixel edge (XRCMT) and to <100 nm/pixel edge (LCSM) illustrates track geometry and interaction of particles with aerogel, including rifling, particle fragmentation, and final particle location. We present a 3-D deconvolution method using an estimated point-spread function for aerogel, allowing basic corrections of LCSM data for axial distortion. LCSM allows rapid, comprehensive, non-destructive, high information return analysis of tracks in aerogel keystones, prior to destructive grain extraction. SRXRF with LCSM allows spatial correlation of grain size, chemical, and mineralogical data. If optical methods are precluded in future aerogel capture missions, XRCMT is a viable 3D imaging technique. Combinations of these methods allow for complete, nondestructive, quantitative 3-D analysis of captured materials at high spatial resolution. This data is fundamental to understanding the hypervelocity particle-aerogel interaction histories of Stardust grains.

  16. Electrochemical etching amplification of low-let recoil particle tracks in polymers for fast neutron dosimetry

    International Nuclear Information System (INIS)

    An electrochemical etching method for the amplification of fast-neutron-induced recoil particle tracks in polymers was investigated. The technique gave superior results over those obtained by conventional etching methods especially when polycarbonate foils were used for recoil particle track amplification. Electrochemical etching systems capable of multi-foil processing were designed and constructed to demonstrate the feasibility of the techniques for large-scale neutron dosimetry. Electrochemical etching parameters were studied including the nature or type of the polymer foil used, foil thickness and its effect on etching time, the applied voltage and its frequency, the chemical composition, concentration, and temperature of the etchant, distance and angle between the electrodes, and the type of particles such as recoil particles including protons. Recoil particle track density, mean track diameter, and optical density as functions of the mentioned parameters were determined. Each parameter was found to have a distinct effect on the etching results in terms of the measured responses. Several new characteristics of this fast neutron dosimetry method were studied especially for personnel dosimetry using various radiation sources such as nuclear reactors, medical cyclotrons, and isotopic neutron sources. The dose range, neutron energy dependence, directional response, fading characteristics, neutron threshold energy, etc. were investigated

  17. Holographic time-resolved particle tracking by means of three-dimensional volumetric deconvolution

    CERN Document Server

    Latychevskaia, Tatiana

    2014-01-01

    Holographic particle image velocimetry allows tracking particle trajectories in time and space by means of holography. However, the drawback of the technique is that in the three-dimensional particle distribution reconstructed from a hologram, the individual particles can hardly be resolved due to the superimposed out-of-focus signal from neighboring particles. We demonstrate here a three-dimensional volumetric deconvolution applied to the reconstructed wavefront which results in resolving all particles simultaneously in three-dimensions. Moreover, we apply the three-dimensional volumetric deconvolution to reconstructions of a time-dependent sequence of holograms of an ensemble of polystyrene spheres moving in water. From each hologram we simultaneously resolve all particles in the ensemble in three dimensions and from the sequence of holograms we obtain the time-resolved trajectories of individual polystyrene spheres.

  18. 3D tracking the Brownian motion of colloidal particles using digital holographic microscopy and joint reconstruction

    CERN Document Server

    Verrier, Nicolas; Fournel, Thierry

    2015-01-01

    In-line digital holography is a valuable tool for sizing, locating and tracking micro- or nano-objects in a volume. When a parametric imaging model is available, Inverse Problems approaches provide a straightforward estimate of the object parameters by fitting data with the model, thereby allowing accurate reconstruction. As recently proposed and demonstrated, combining pixel super-resolution techniques with Inverse Problems approaches improves the estimation of particle size and 3D-position. Here we demonstrate the accurate tracking of colloidal particles in Brownian motion. Particle size and 3D-position are jointly optimized from video holograms acquired with a digital holographic microscopy set up based on a "low-end" microscope objective ($\\times 20$, $\\rm NA\\ 0.5$). Exploiting information redundancy makes it possible to characterize particles with a standard deviation of 15 nm in size and a theoretical resolution of 2 x 2 x 5 nm$^3$ for position under additive white Gaussian noise assumption.

  19. A transition radiation detector for RHIC featuring accurate tracking and dE/dx particle identification

    Energy Technology Data Exchange (ETDEWEB)

    O`Brien, E.; Lissauer, D.; McCorkle, S.; Polychronakos, V.; Takai, H. [Brookhaven National Lab., Upton, NY (United States); Chi, C.Y.; Nagamiya, S.; Sippach, W.; Toy, M.; Wang, D.; Wang, Y.F.; Wiggins, C.; Willis, W. [Columbia Univ., New York, NY (United States); Cherniatin, V.; Dolgoshein, B. [Moscow Institute of Physics and Engineering, (Russian Federation); Bennett, M.; Chikanian, A.; Kumar, S.; Mitchell, J.T.; Pope, K. [Yale Univ., New Haven, CT (United States)

    1991-12-31

    We describe the results of a test ran involving a Transition Radiation Detector that can both distinguish electrons from pions which momenta greater titan 0.7 GeV/c and simultaneously track particles passing through the detector. The particle identification is accomplished through a combination of the detection of Transition Radiation from the electron and the differences in electron and pion energy loss (dE/dx) in the detector. The dE/dx particle separation is most, efficient below 2 GeV/c while particle ID utilizing Transition Radiation effective above 1.5 GeV/c. Combined, the electron-pion separation is-better than 5 {times} 10{sup 2}. The single-wire, track-position resolution for the TRD is {approximately}230 {mu}m.

  20. VOLTAGE REGULATORS ASYNCHRONOUS GENERATORS

    Directory of Open Access Journals (Sweden)

    Grigorash O. V.

    2015-06-01

    Full Text Available A promising is currently the use of asynchronous generators with capacitive excitation as a source of electricity in stand-alone power systems. Drive asynchronous generators may exercise as a thermal engine and wind wheel wind power plant or turbines of small hydropower plants. The article discusses the structural and schematics of voltage stabilizers and frequency of asynchronous generators with improved operational and technical specifications. Technical novelty of design solutions of the magnetic system and stabilizers asynchronous generator of electricity parameters confirmed by the patents for the invention of the Russian Federation. The proposed technical solution voltage stabilizer asynchronous generators, can reduce the weight of the block capacitors excitation and reactive power compensation, as well as to simplify the control system power circuit which has less power electronic devices. For wind power plants it is an important issue not only to stabilize the voltage of the generator, but also the frequency of the current. Recommend functionality stabilizer schemes parameters of electric power made for direct frequency converters with artificial and natural switching power electronic devices. It is also proposed as part of stabilization systems use single-phase voltage, three-phase transformers with rotating magnetic field, reduce the level of electromagnetic interference generated by power electronic devices for switching, enhance the efficiency and reliability of the stabilizer.

  1. Probabilistic Data Association-Feedback Particle Filter for Multiple Target Tracking Applications

    OpenAIRE

    Yang, Tao; Mehta, Prashant G.

    2014-01-01

    This paper is concerned with the problem of tracking single or multiple targets with multiple non-target specific observations (measurements). For such filtering problems with data association uncertainty, a novel feedback control-based particle filter algorithm is introduced. The algorithm is referred to as the probabilistic data association-feedback particle filter (PDA-FPF). The proposed filter is shown to represent a generalization to the nonlinear non-Gaussian case of the classical Kalma...

  2. Calibrations for Charged Particle Tracking with the GlueX Detector

    Science.gov (United States)

    Staib, Michael; GlueX Collaboration

    2015-10-01

    Two gas detectors comprise the tracking system for the GlueX experiment, the Central Drift Chamber (CDC) and the Forward Drift Chamber (FDC). The CDC is a cylindrical straw-tube detector covering polar angles between 6° and 168°, delivering spatial resolution of ~150 μm. The FDC is a Cathode Strip Chamber consisting of four packages, each with six alternating layers of anode wires and cathode strips. The FDC is designed to track forward-going charged particles with polar angles between 1° and 20° with a spatial resolution of ~200 μm. Both tracking detectors record timing information and energy loss measurements useful for particle identification. During Fall 2014 and Spring 2015, the first photon beam was delivered on target for commissioning of the GlueX detector in Hall-D at Jefferson Lab. These data are currently being used in a large effort to calibrate the individual detector subsystems to achieve design performance. Methods and results for calibrations of each of the tracking detectors are presented. Techniques for alignment of the tracking system using a combination of cosmic rays and beam data is discussed. Finally, some early results of physics measurements including charged final-state particles are presented. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract DE-AC05-06OR23177.

  3. 3D head pose estimation and tracking using particle filtering and ICP algorithm

    KAUST Repository

    Ben Ghorbel, Mahdi

    2010-01-01

    This paper addresses the issue of 3D head pose estimation and tracking. Existing approaches generally need huge database, training procedure, manual initialization or use face feature extraction manually extracted. We propose a framework for estimating the 3D head pose in its fine level and tracking it continuously across multiple Degrees of Freedom (DOF) based on ICP and particle filtering. We propose to approach the problem, using 3D computational techniques, by aligning a face model to the 3D dense estimation computed by a stereo vision method, and propose a particle filter algorithm to refine and track the posteriori estimate of the position of the face. This work comes with two contributions: the first concerns the alignment part where we propose an extended ICP algorithm using an anisotropic scale transformation. The second contribution concerns the tracking part. We propose the use of the particle filtering algorithm and propose to constrain the search space using ICP algorithm in the propagation step. The results show that the system is able to fit and track the head properly, and keeps accurate the results on new individuals without a manual adaptation or training. © Springer-Verlag Berlin Heidelberg 2010.

  4. High throughput on-chip analysis of high-energy charged particle tracks using lensfree imaging

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Wei; Shabbir, Faizan; Gong, Chao; Gulec, Cagatay; Pigeon, Jeremy; Shaw, Jessica; Greenbaum, Alon; Tochitsky, Sergei; Joshi, Chandrashekhar [Electrical Engineering Department, University of California, Los Angeles, California 90095 (United States); Ozcan, Aydogan, E-mail: ozcan@ucla.edu [Electrical Engineering Department, University of California, Los Angeles, California 90095 (United States); Bioengineering Department, University of California, Los Angeles, California 90095 (United States); California NanoSystems Institute (CNSI), University of California, Los Angeles, California 90095 (United States)

    2015-04-13

    We demonstrate a high-throughput charged particle analysis platform, which is based on lensfree on-chip microscopy for rapid ion track analysis using allyl diglycol carbonate, i.e., CR-39 plastic polymer as the sensing medium. By adopting a wide-area opto-electronic image sensor together with a source-shifting based pixel super-resolution technique, a large CR-39 sample volume (i.e., 4 cm × 4 cm × 0.1 cm) can be imaged in less than 1 min using a compact lensfree on-chip microscope, which detects partially coherent in-line holograms of the ion tracks recorded within the CR-39 detector. After the image capture, using highly parallelized reconstruction and ion track analysis algorithms running on graphics processing units, we reconstruct and analyze the entire volume of a CR-39 detector within ∼1.5 min. This significant reduction in the entire imaging and ion track analysis time not only increases our throughput but also allows us to perform time-resolved analysis of the etching process to monitor and optimize the growth of ion tracks during etching. This computational lensfree imaging platform can provide a much higher throughput and more cost-effective alternative to traditional lens-based scanning optical microscopes for ion track analysis using CR-39 and other passive high energy particle detectors.

  5. Correlation of Particle Traversals with Clonogenic Survival Using Cell-Fluorescent Ion Track Hybrid Detector

    Directory of Open Access Journals (Sweden)

    Ivana eDokic

    2015-12-01

    Full Text Available Development of novel approaches linking the physical characteristics of particles with biological responses are of high relevance for the field of particle therapy. In radiobiology, the clonogenic survival of cells is considered the gold standard assay for assessment of cellular sensitivity to ionizing radiation. Towards further development of next generation biodosimeters in particle therapy, cell-fluorescent ion track hybrid detector (Cell-FIT-HD was recently engineered by our group and successfully employed to study physical particle track information in correlation with irradiation- induced DNA damage in cell nuclei. In this work, we investigated the feasibility of Cell-FIT-HD as a tool to study the effects of clinical beams on cellular clonogenic survival. Tumor cells were grown on the FNTD as cell culture, mimicking the standard procedures for clonogenic assay. Cell-FIT-HD was used to detect the spatial distribution of particle tracks within colony-initiating cells. The physical data were associated to radiation induced foci as surrogates for DNA double strand breakages (DSB, the hallmark of radiation ‐induced cell lethality. Long‐term cell fate was monitored to determine the ability of cells to form colonies. We report the first successful detection of particle traversal within colony-initiating cells at subcellular resolution using Cell-FIT-HD.

  6. User guide for MODPATH version 6 - A particle-tracking model for MODFLOW

    Science.gov (United States)

    Pollock, David W.

    2012-01-01

    MODPATH is a particle-tracking post-processing model that computes three-dimensional flow paths using output from groundwater flow simulations based on MODFLOW, the U.S. Geological Survey (USGS) finite-difference groundwater flow model. This report documents MODPATH version 6. Previous versions were documented in USGS Open-File Reports 89-381 and 94-464. The program uses a semianalytical particle-tracking scheme that allows an analytical expression of a particle's flow path to be obtained within each finite-difference grid cell. A particle's path is computed by tracking the particle from one cell to the next until it reaches a boundary, an internal sink/source, or satisfies another termination criterion. Data input to MODPATH consists of a combination of MODFLOW input data files, MODFLOW head and flow output files, and other input files specific to MODPATH. Output from MODPATH consists of several output files, including a number of particle coordinate output files intended to serve as input data for other programs that process, analyze, and display the results in various ways. MODPATH is written in FORTRAN and can be compiled by any FORTRAN compiler that fully supports FORTRAN-2003 or by most commercially available FORTRAN-95 compilers that support the major FORTRAN-2003 language extensions.

  7. Particle filter based visual tracking with multi-cue adaptive fusion

    Institute of Scientific and Technical Information of China (English)

    Anping Li; Zhongliang Jing; Shiqiang Hu

    2005-01-01

    @@ To improve the robustness of visual tracking in complex environments such as: cluttered backgrounds, partial occlusions, similar distraction and pose variations, a novel tracking method based on adaptive fusion and particle filter is proposed in this paper. In this method, the image color and shape cues are adaptively fused to represent the target observation; fuzzy logic is applied to dynamically adjust each cue weight according to its associated reliability in the past frame; particle filter is adopted to deal with non-linear and non-Gaussian problems in visual tracking. The method is demonstrated to be robust to illumination changes, pose variations, partial occlusions, cluttered backgrounds and camera motion for a test image sequence.

  8. Multiple Maneuvering Target Tracking by Improved Particle Filter Based on Multiscan JPDA

    Directory of Open Access Journals (Sweden)

    Jing Liu

    2012-01-01

    Full Text Available The multiple maneuvering target tracking algorithm based on a particle filter is addressed. The equivalent-noise approach is adopted, which uses a simple dynamic model consisting of target state and equivalent noise which accounts for the combined effects of the process noise and maneuvers. The equivalent-noise approach converts the problem of maneuvering target tracking to that of state estimation in the presence of nonstationary process noise with unknown statistics. A novel method for identifying the nonstationary process noise is proposed in the particle filter framework. Furthermore, a particle filter based multiscan Joint Probability Data Association (JPDA filter is proposed to deal with the data association problem in a multiple maneuvering target tracking. In the proposed multiscan JPDA algorithm, the distributions of interest are the marginal filtering distributions for each of the targets, and these distributions are approximated with particles. The multiscan JPDA algorithm examines the joint association events in a multiscan sliding window and calculates the marginal posterior probability based on the multiscan joint association events. The proposed algorithm is illustrated via an example involving the tracking of two highly maneuvering, at times closely spaced and crossed, targets, based on resolved measurements.

  9. Optical imaging of charged particle tracks in a gas. Final report

    International Nuclear Information System (INIS)

    The development of a new detector designed to optically image the track of a charged particle in a gas is outlined. In the detector, a pulsed high-voltage (up to ∼ 30--40 kV), high-frequency (f = 27.125 MHz) RF field is temporarily applied (pulse duration ∼ 1--3 μs) across a pair of electrodes, immediately following, or alternatively, just prior to the passage of a charged particle through the chamber. The pulsed RF field excites the subexcitation electrons left along the particle's path leading to excitation and ionization of the surrounding gas and the emission of light. The track is then imaged by a fast intensified digital camera (shutter speed ∼ 0.1--5 μs). The image is recorded in a two-dimensional pixel array (512 x 512 pixels) within the camera, and transferred to a computer for later analysis. The detector has been operated over the total gas pressure range 2.5--100 kPa (20--750 torr) using a gas mixture of 2--10% N2 in Ar. Images of both α and β tracks obtained with this detector are discussed to demonstrate the usefulness of the present technique in charged-particle track analysis for dosimetry and microdosimetry applications

  10. Test of scintillating bars coupled to Silicon Photomultipliers for a charged particle tracking device

    CERN Document Server

    Cecchini, S; Esposti, L Degli; Lax, I; Mandrioli, G; Mauri, N; Pasqualini, L; Patrizii, L; Pozzato, M; Sirri, G; Tenti, M

    2016-01-01

    The results obtained in laboratory tests, using scintillator bars read by silicon photomultipliers are reported. The present approach is the first step for designing a precision tracking system to be placed inside a free magnetized volume for the charge identification of low energy crossing particles. The devised system is demonstrated able to provide a spatial resolution better than 2 mm.

  11. Particle filtering for obstacle tracking in UAS sense and avoid applications.

    Science.gov (United States)

    Tirri, Anna Elena; Fasano, Giancarmine; Accardo, Domenico; Moccia, Antonio

    2014-01-01

    Obstacle detection and tracking is a key function for UAS sense and avoid applications. In fact, obstacles in the flight path must be detected and tracked in an accurate and timely manner in order to execute a collision avoidance maneuver in case of collision threat. The most important parameter for the assessment of a collision risk is the Distance at Closest Point of Approach, that is, the predicted minimum distance between own aircraft and intruder for assigned current position and speed. Since assessed methodologies can cause some loss of accuracy due to nonlinearities, advanced filtering methodologies, such as particle filters, can provide more accurate estimates of the target state in case of nonlinear problems, thus improving system performance in terms of collision risk estimation. The paper focuses on algorithm development and performance evaluation for an obstacle tracking system based on a particle filter. The particle filter algorithm was tested in off-line simulations based on data gathered during flight tests. In particular, radar-based tracking was considered in order to evaluate the impact of particle filtering in a single sensor framework. The analysis shows some accuracy improvements in the estimation of Distance at Closest Point of Approach, thus reducing the delay in collision detection. PMID:25105154

  12. Particle Filtering for Obstacle Tracking in UAS Sense and Avoid Applications

    Directory of Open Access Journals (Sweden)

    Anna Elena Tirri

    2014-01-01

    Full Text Available Obstacle detection and tracking is a key function for UAS sense and avoid applications. In fact, obstacles in the flight path must be detected and tracked in an accurate and timely manner in order to execute a collision avoidance maneuver in case of collision threat. The most important parameter for the assessment of a collision risk is the Distance at Closest Point of Approach, that is, the predicted minimum distance between own aircraft and intruder for assigned current position and speed. Since assessed methodologies can cause some loss of accuracy due to nonlinearities, advanced filtering methodologies, such as particle filters, can provide more accurate estimates of the target state in case of nonlinear problems, thus improving system performance in terms of collision risk estimation. The paper focuses on algorithm development and performance evaluation for an obstacle tracking system based on a particle filter. The particle filter algorithm was tested in off-line simulations based on data gathered during flight tests. In particular, radar-based tracking was considered in order to evaluate the impact of particle filtering in a single sensor framework. The analysis shows some accuracy improvements in the estimation of Distance at Closest Point of Approach, thus reducing the delay in collision detection.

  13. Kalman-Filter-Based Particle Tracking on Parallel Architectures at Hadron Colliders

    CERN Document Server

    Cerati, Giuseppe; Lantz, Steven; McDermott, Kevin; Riley, Dan; Tadel, Matevž; Wittich, Peter; Würthwein, Frank; Yagil, Avi

    2016-01-01

    Power density constraints are limiting the performance improvements of modern CPUs. To address this we have seen the introduction of lower-power, multi-core processors such as GPGPU, ARM and Intel MIC. To stay within the power density limits but still obtain Moore's Law performance/price gains, it will be necessary to parallelize algorithms to exploit larger numbers of lightweight cores and specialized functions like large vector units. Track finding and fitting is one of the most computationally challenging problems for event reconstruction in particle physics. At the High-Luminosity Large Hadron Collider (HL-LHC), for example, this will be by far the dominant problem. The need for greater parallelism has driven investigations of very different track finding techniques such as Cellular Automata or Hough Transforms. The most common track finding techniques in use today, however, are those based on the Kalman Filter. Significant experience has been accumulated with these techniques on real tracking detector sy...

  14. Guitarist Fingertip Tracking by Integrating a Bayesian Classifier into Particle Filters

    Directory of Open Access Journals (Sweden)

    Chutisant Kerdvibulvech

    2008-01-01

    Full Text Available We propose a vision-based method for tracking guitar fingerings made by guitar players. We present it as a new framework for tracking colored finger markers by integrating a Bayesian classifier into particle filters. This adds the useful abilities of automatic track initialization and recovery from tracking failures in a dynamic background. Furthermore, by using the online adaptation of color probabilities, this method is able to cope with illumination changes. Augmented Reality Tag (ARTag is then utilized to calculate the projection matrix as an online process which allows the guitar to be moved while being played. Representative experimental results are also included. The method presented can be used to develop the application of human-computer interaction (HCI to guitar playing by recognizing the chord being played by a guitarist in virtual spaces. The aforementioned application would assist guitar learners by allowing them to automatically identify if they are using the correct chords required by the musical piece.

  15. Particle tracking with iterated Kalman filters and smoothers the PMHT algorithm

    CERN Document Server

    Strandlie, A

    1999-01-01

    We introduce the Probabilistic Multi-Hypothesis Tracking (PMHT) algorithm for particle tracking in high-energy physics detectors. This algorithm has been developed recently for tracking multiple targets in clutter, and it is based on maximum likelihood estimation with help of the EM algorithm. The resulting algorithm basically consists of running several iterated and coupled Kalman filters and smoothers in parallel. It is similar to the Elastic Arms algorithm, but it possesses the additional feature of being able to take process noise into account, as for instance multiple Coulomb scattering. Herein, we review its basic properties and derive a generalized version of the algorithm by including a deterministic annealing scheme. Further developments of the algorithm in order to improve the performance are also discussed. In particular, we propose to modify the hit-to-track assignment probabilities in order to obtain competition between hits in the same detector layer. Finally, we present results of an implementa...

  16. Innovative Method Using Magnetic Particle Tracking to Measure Solids Circulation in a Spouted Bed

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, Ms. Emily [Waynesburg University; Halow, John [Waynesburg University; Daw, C Stuart [ORNL

    2010-01-01

    We describe an innovative method for measuring particle motion inside spouted fluidized beds. The method uses a magnetic tracer particle, which follows the bulk particle flow and is continuously tracked by multiple magnetic field detectors located outside the bed. We analyze signals from the detectors to determine the tracer position at each instant in time. From statistical analysis of the tracer trajectory, characteristic measures of the bulk particle flow, such as the average recirculation frequency, can be determined as a function of operating conditions. For experiments with a range of particle sizes and densities in a 3.9-cm-diameter spouted bed, we find that average solids recirculation rates correlate with excess velocity (superficial minus minimum spouting velocity), particle density, and bed depth.

  17. Innovative method using magnetic particle tracking to measure solids circulation in a spouted fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, Ms. Emily [Waynesburg University; Halow, John [Waynesburg University; Daw, C Stuart [ORNL

    2009-01-01

    We describe an innovative method for measuring particle motion inside spouted fluidized beds. The method uses a magnetic tracer particle, which follows the bulk particle flow and is continuously tracked by multiple magnetic field detectors located outside the bed. We analyze signals from the detectors to determine the tracer position at each instant in time. From statistical analysis of the tracer trajectory, characteristic measures of the bulk particle flow, such as the average recirculation frequency, can be determined as a function of operating conditions. For experiments with a range of particle sizes and densities in a 3.9-cm-diameter spouted bed, we find that average solids recirculation rates correlate with excess velocity (superficial minus minimum spouting velocity), particle density, and bed depth.

  18. Asynchronized synchronous machines

    CERN Document Server

    Botvinnik, M M

    1964-01-01

    Asynchronized Synchronous Machines focuses on the theoretical research on asynchronized synchronous (AS) machines, which are "hybrids” of synchronous and induction machines that can operate with slip. Topics covered in this book include the initial equations; vector diagram of an AS machine; regulation in cases of deviation from the law of full compensation; parameters of the excitation system; and schematic diagram of an excitation regulator. The possible applications of AS machines and its calculations in certain cases are also discussed. This publication is beneficial for students and indiv

  19. Age and uranium content of soil micas from Antarctica by the fission particle track replica method

    International Nuclear Information System (INIS)

    A replica method was developed for fission particle track age dating and determination of uranium content of micas in a Wright Valley, Antarctica, soil and parent rock. The mica particles in the soil were relatively small, fragile, and easily dissolved by chemical etchings. Muscovite mica flakes were therefore used as a replicating substrate to register induced fission tracks of the soil mica. The micas from three soil horizons (0 to 10, 10 to 30, and 30 to 50 cm depths) and parent rock, in four size fractions (100 to 500, 2 to 5, 0.2 to 2, and <0.2μm) were examined to illustrate use of the method. The fission track age of the soil mica particles was 4.1 +- 0.2 million years (MY), slightly older than the minimum landscape (glacial bench) age of 3.7 +- 0.2 MY obtained previously by K-Ar dating of a volcanic cone formed after the glacial valley was formed. The ages of the 2 to 5, 0.2 to 2, and <0.2μm fractions were the same as for the 100 to 500 μm flakes, when the spontaneous track density was calculated from that of the latter, in proportion to the U content. The fission track age of parent rock mica was 151 million years. The U content of the soil mica was 0.5 to 1.6 ppM which is 20 to 50 times higher than that of mica from the parent rock (0.03 ppM). The mica in the soil appears from age and petrographic thin-section results to be of pedogenic origin, formed by replacement in feldspars after the bench was carved. The fission particle track replica method is useful for age-dating of micas in soils, for determining trace amounts of uranium in micas, and for study of soil genesis in the Antarctic cold desert

  20. An application of 222Rn alpha particle's tracks to uranium exploration

    International Nuclear Information System (INIS)

    The uranium exploration method is based on the register of 222Rn alpha particles; 222Rn gas is generated in the chain 238U desintegration. The detection of alpha particles was performed with cellulose nitrate films (NTC), located in a grid at the region in study. The alpha particles produce latent tracks in the NTC films; these tracks may be enlarged by chemical etching and are observed with an ordinary optic microscope, ninety seven NTC films were used, these were distributed in an area of approximately seventeen square kilometers, located in the municipalities of Granados and Huasabas in Sonora Mexico, the detectors remain in the ground for a thirty days mean period. The results obtained show an area with high 222Rn concentration, this can be related with an underground uranium ore deposit. The more important conclusion is that the results obtained in this work can be used as preliminary results for other prospection methods in this particular area. (author)

  1. Elastic collisions of classical point particles on a finite frictionless linear track with perfectly reflecting endpoints

    Science.gov (United States)

    DeLuca, R.

    2006-03-01

    Repeated elastic collisions of point particles on a finite frictionless linear track with perfectly reflecting endpoints are considered. The problem is analysed by means of an elementary linear algebra approach. It is found that, starting with a state consisting of a projectile particle in motion at constant velocity and a target particle at rest in a fixed known position, the points at which collisions occur on track, when plotted versus progressive numerals, corresponding to the collisions themselves, show periodic patterns for a rather large choice of values of the initial position x(0) and on the mass ratio r. For certain values of these parameters, however, only regular behaviour over a large number of collisions is detected.

  2. Software manual for operating particle displacement tracking data acquisition and reduction system

    Science.gov (United States)

    Wernet, Mark P.

    1991-01-01

    The software manual is presented. The necessary steps required to record, analyze, and reduce Particle Image Velocimetry (PIV) data using the Particle Displacement Tracking (PDT) technique are described. The new PDT system is an all electronic technique employing a CCD video camera and a large memory buffer frame-grabber board to record low velocity (less than or equal to 20 cm/s) flows. Using a simple encoding scheme, a time sequence of single exposure images are time coded into a single image and then processed to track particle displacements and determine 2-D velocity vectors. All the PDT data acquisition, analysis, and data reduction software is written to run on an 80386 PC.

  3. Asynchronous P300 BCI

    DEFF Research Database (Denmark)

    Panicker, Rajesh; Puthusserypady, Sadasivan; Sun, Ying

    2010-01-01

    An asynchronous hybrid brain-computer interface (BCI) system combining the P300 and steady-state visually evoked potentials (SSVEP) paradigms is introduced. A P300 base system is used for information transfer, and is augmented to include SSVEP for control state detection. The proposed system has...

  4. Asynchronous Multiparty Computation

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Geisler, Martin; Krøigaard, Mikkel;

    2009-01-01

    less than n/3 players. We also present a software framework for implementation of asynchronous protocols called VIFF (Virtual Ideal Functionality Framework), which allows automatic parallelization of primitive operations such as secure multiplications, without having to resort to complicated...

  5. Redundant Asynchronous Microprocessor System

    Science.gov (United States)

    Meyer, G.; Johnston, J. O.; Dunn, W. R.

    1985-01-01

    Fault-tolerant computer structure called RAMPS (for redundant asynchronous microprocessor system) has simplicity of static redundancy but offers intermittent-fault handling ability of complex, dynamically redundant systems. New structure useful wherever several microprocessors are employed for control - in aircraft, industrial processes, robotics, and automatic machining, for example.

  6. Etching characteristic studies for the detection of alpha particles in DAM–ADC nuclear track detector

    International Nuclear Information System (INIS)

    This study reports the characteristic studies for the detection of alpha particles in DAM–ADC nuclear track detector. Several important parameters that control the track formation such as, the bulk etch rate (VB), track etching rate (VT), dependence of VB and VT on etching concentration and temperature have been extensively studied. The activation energy (Eb) of the bulk etching rate for the DAM–ADC sheets has been calculated, the dependence of etching efficiency and sensitivity upon etchant concentrations and temperature has been investigated, registration efficiency of DAM–ADC detector etched at the optimum etching condition has been examined. The detailed studied results presented in this study provide various useful information about the mechanism of track formation in polymers. - Highlights: • Detection of alpha particles in DAM–ADC nuclear track detector. • The activation energy of the bulk etching rate for the DAM–ADC sheets. • The dependence of etching efficiency upon etchant concentrations • Registration efficiency of DAM–ADC detector

  7. Particle position and velocity measurement in dusty plasmas using particle tracking velocimetry

    Science.gov (United States)

    Feng, Yan; Goree, J.; Haralson, Zach; Wong, Chun-Shang; Kananovich, A.; Li, Wei

    2016-06-01

    > Methods of imaging and image analysis are presented for dusty plasma experiments. Micron-sized polymer spheres, electrically suspended in a partially ionized gas, are illuminated by a sheet of laser light and imaged by video cameras. Image analysis methods yield particle positions and velocities of individual particles in each video image. Methods to minimize errors in the particle positions and velocities, which are now commonly used in the dusty plasma community, are described.

  8. 基于强跟踪滤波算法的异步电机参数自适应无速度传感器控制%Parameter Adaptation Sensorless Control of Asynchronous Motor Based on Strong Track Filter

    Institute of Scientific and Technical Information of China (English)

    陆可

    2011-01-01

    在异步电机四阶模型的基础上增加机械和转矩方程,并引入负载转矩和转子电阻为状态变量,得到七阶非线性模型.利用强跟踪滤波(STF)算法实现电机状态和转子电阻的同时估计,通过仿真比较了STF和扩展Kalman滤波(EKF)算法的估计性能.结果表明,STF算法能有效估计电机状态及辨识转子电阻,并且具有比EKF算法更理想的估计性能,同时能满足极低速和零速下的估计要求,从而在电机的整个工作范围内实现转子电阻自适应的状态估计.%The equations of machine and torque were added to the fourth-order model of asynchronous motor.A seventh-order nonlinear model was obtained via increasing load torque and rotor resistance as state variables.The motor states and the rotor resistance were estimated simultaneously using strong track filter (STF).Computer simulations were performed to compare the estimation performance between STF and EKF.The results illustrated that STF could estimate the motor states and the rotor resistance effectively, and its performance was more perfect than EKF' s.STF could also satisfy the estimation request running at very low and zero speed, thus it could realize the states estimation with rotor resistance adaptation in the whole operation range.

  9. Particle tracking in kaon electroproduction with cathode-charge sampling in multi-wire proportional chambers

    Energy Technology Data Exchange (ETDEWEB)

    Achenbach, P., E-mail: patrick@kph.uni-mainz.de [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Ayerbe Gayoso, C.; Bernauer, J.C.; Boehm, R. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Bosnar, D. [Department of Physics, University of Zagreb (Croatia); Boesz, M. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Debenjak, L. [University of Ljubljana and Jozef Stefan Institute, Ljubljana (Slovenia); Distler, M.O.; Esser, A. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Friscic, I. [Department of Physics, University of Zagreb (Croatia); Gomez Rodriguez de la Paz, M. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Makek, M. [Department of Physics, University of Zagreb (Croatia); Merkel, H.; Mueller, U.; Nungesser, L.; Pochodzalla, J. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Potokar, M. [University of Ljubljana and Jozef Stefan Institute, Ljubljana (Slovenia); Sanchez Majos, S.; Schlimme, B.S. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Sirca, S. [University of Ljubljana and Jozef Stefan Institute, Ljubljana (Slovenia)

    2011-06-11

    Wire chambers are routinely operated as tracking detectors in magnetic spectrometers at high-intensity continuous electron beams. Especially in experiments studying reactions with small cross-sections the reaction yield is limited by the background rate in the chambers. One way to determine the track of a charged particle through a multi-wire proportional chamber (MWPC) is the measurement of the charge distribution induced on its cathodes. In practical applications of this read-out method, the algorithm to relate the measured charge distribution to the avalanche position is an important factor for the achievable position resolution and for the track reconstruction efficiency. An algorithm was developed for operating two large-sized MWPCs in a strong background environment with multiple-particle tracks. Resulting efficiencies were determined as a function of the electron beam current and on the signal amplitudes. Because of the different energy-losses of pions, kaons, and protons in the momentum range of the spectrometer the efficiencies depend also on the particle species.

  10. Improved estimation of anomalous diffusion exponents in single particle tracking experiments

    CERN Document Server

    Bronshtein, Eldad Kepten Irena

    2013-01-01

    The Mean Square Displacement is a central tool in the analysis of Single Particle Tracking experiments, shedding light on various biophysical phenomena. Frequently, parameters are extracted by performing time-averages on single particle trajectories followed by ensemble averaging. This procedure however, suffers from two systematic errors when applied to particles that perform anomalous diffusion. The first is significant at short time lags and is induced by measurement errors. The second arises from the natural heterogeneity in biophysical systems. We show how to estimate and correct these two errors and improve the estimation of the anomalous parameters for the whole particle distribution. As a consequence we manage to characterize ensembles of heterogeneous particles even for rather short and noisy measurements where regular time averaged mean square displacement analysis fails. We apply this method to both simulations and in vivo measurements of telomere diffusion in 3T3 mouse embryonic fibroblast cells. ...

  11. Real-Time MRI-Guided Catheter Tracking Using Hyperpolarized Silicon Particles

    Science.gov (United States)

    Whiting, Nicholas; Hu, Jingzhe; Shah, Jay V.; Cassidy, Maja C.; Cressman, Erik; Zacharias Millward, Niki; Menter, David G.; Marcus, Charles M.; Bhattacharya, Pratip K.

    2015-08-01

    Visualizing the movement of angiocatheters during endovascular interventions is typically accomplished using x-ray fluoroscopy. There are many potential advantages to developing magnetic resonance imaging-based approaches that will allow three-dimensional imaging of the tissue/vasculature interface while monitoring other physiologically-relevant criteria, without exposing the patient or clinician team to ionizing radiation. Here we introduce a proof-of-concept development of a magnetic resonance imaging-guided catheter tracking method that utilizes hyperpolarized silicon particles. The increased signal of the silicon particles is generated via low-temperature, solid-state dynamic nuclear polarization, and the particles retain their enhanced signal for ≥40 minutes—allowing imaging experiments over extended time durations. The particles are affixed to the tip of standard medical-grade catheters and are used to track passage under set distal and temporal points in phantoms and live mouse models. With continued development, this method has the potential to supplement x-ray fluoroscopy and other MRI-guided catheter tracking methods as a zero-background, positive contrast agent that does not require ionizing radiation.

  12. Detection of high energy neutrons, protons and He particles by solid state nuclear track detectors

    Energy Technology Data Exchange (ETDEWEB)

    Palfalvi, J.K., E-mail: Palfalvi@aeki.kfki.h [HAS KFKI Atomic Energy Research Institute, P.O.B. 49, 1525 Budapest (Hungary); Szabo, J. [HAS KFKI Atomic Energy Research Institute, P.O.B. 49, 1525 Budapest (Hungary); Eoerdoegh, I. [HAS Research Institute for Technical Physics and Materials Science, P.O.B. 49, 1525 Budapest (Hungary)

    2010-12-15

    The career of astronauts is dependent mostly on the lifetime dose received from primary cosmic rays and secondary particles generated within the structuring materials of a space craft. Since the high energy protons and He particles have the highest abundance and the secondary neutrons significantly contribute to the dose, the study of the response of solid state nuclear track detectors (SSNTD) to these particles has a great importance. SSNTDs, having been used for dosimetry on the International Space Station (ISS), were exposed to protons at several accelerators (Loma-Linda, BNL, TSL), to He (HIMAC) and to neutrons (iThemba, TSL). The incident particles cause fragmentation of the constituent elements of the SSNTD composed of C{sub 12}H{sub 18}O{sub 7}. The fragments induce latent tracks inside the detector which can be visualized by chemical processes and investigated by optical microscope. The measurable track parameters and appropriate calibration allow to determine the linear energy transfer (LET) spectrum of the fragments and also the absorbed dose in the nearly tissue equivalent detector material. The LET spectra of different exposures are presented and compared. Additionally, a LET spectrum determined from the MATROSHKA space walk simulation outside the International Space Station (ISS) will be compared to some of those obtained from accelerator experiments.

  13. Parallel computing of a digital hologram and particle searching for microdigital-holographic particle-tracking velocimetry

    Science.gov (United States)

    Satake, Shin-Ichi; Kanamori, Hiroyuki; Kunugi, Tomoaki; Sato, Kazuho; Ito, Tomoyoshi; Yamamoto, Keisuke

    2007-02-01

    We have developed a parallel algorithm for microdigital-holographic particle-tracking velocimetry. The algorithm is used in (1) numerical reconstruction of a particle image computer using a digital hologram, and (2) searching for particles. The numerical reconstruction from the digital hologram makes use of the Fresnel diffraction equation and the FFT (fast Fourier transform), whereas the particle search algorithm looks for local maximum graduation in a reconstruction field represented by a 3D matrix. To achieve high performance computing for both calculations (reconstruction and particle search), two memory partitions are allocated to the 3D matrix. In this matrix, the reconstruction part consists of horizontally placed 2D memory partitions on the x-y plane for the FFT, whereas, the particle search part consists of vertically placed 2D memory partitions set along the z axes. Consequently, the scalability can be obtained for the proportion of processor elements, where the benchmarks are carried out for parallel computation by a SGI Altix machine.

  14. Magnetic poly(lactide-co-glycolide) and cellulose particles for MRI-based cell tracking.

    Science.gov (United States)

    Nkansah, Michael K; Thakral, Durga; Shapiro, Erik M

    2011-06-01

    Biodegradable, superparamagnetic microparticles and nanoparticles of poly(lactide-co-glycolide) (PLGA) and cellulose were designed, fabricated, and characterized for magnetic cell labeling. Monodisperse nanocrystals of magnetite were incorporated into microparticles and nanoparticles of PLGA and cellulose with high efficiency using an oil-in-water single emulsion technique. Superparamagnetic cores had high magnetization (72.1 emu/g). The resulting polymeric particles had smooth surface morphology and high magnetite content (43.3 wt % for PLGA and 69.6 wt % for cellulose). While PLGA and cellulose nanoparticles displayed highest r 2* values per millimole of iron (399 sec(-1) mM(-1) for cellulose and 505 sec(-1) mM(-1) for PLGA), micron-sized PLGA particles had a much higher r 2* per particle than either. After incubation for a month in citrate buffer (pH 5.5), magnetic PLGA particles lost close to 50% of their initial r 2* molar relaxivity, while magnetic cellulose particles remained intact, preserving over 85% of their initial r 2* molar relaxivity. Lastly, mesenchymal stem cells and human breast adenocarcinoma cells were magnetically labeled using these particles with no detectable cytotoxicity. These particles are ideally suited for noninvasive cell tracking in vivo via MRI and due to their vastly different degradation properties, offer unique potential for dedicated use for either short (PLGA-based particles) or long-term (cellulose-based particles) experiments. PMID:21404328

  15. Modeling Bimolecular Reactions and Transport in Porous Media Via Particle Tracking

    Energy Technology Data Exchange (ETDEWEB)

    Dong Ding; David Benson; Amir Paster; Diogo Bolster

    2012-01-01

    We use a particle-tracking method to simulate several one-dimensional bimolecular reactive transport experiments. In this numerical method, the reactants are represented by particles: advection and dispersion dominate the flow, and molecular diffusion dictates, in large part, the reactions. The particle/particle reactions are determined by a combination of two probabilities dictated by the physics of transport and energetics of reaction. The first is that reactant particles occupy the same volume over a short time interval. The second is the conditional probability that two collocated particles favorably transform into a reaction. The first probability is a direct physical representation of the degree of mixing in an advancing displacement front, and as such lacks empirical parameters except for the user-defined number of particles. This number can be determined analytically from concentration autocovariance, if this type of data is available. The simulations compare favorably to two physical experiments. In one, the concentration of product, 1,2-naphthoquinoe-4-aminobenzene (NQAB) from reaction between 1,2-naphthoquinone-4-sulfonic acid (NQS) and aniline (AN), was measured at the outflow of a column filled with glass beads at different times. In the other, the concentration distribution of reactants (CuSO_4 and EDTA^{4-}) and products (CuEDTA^{4-}) were quantified by snapshots of transmitted light through a column packed with cryloite sand. The thermodynamic rate coefficient in the latter experiment was 10^7 times greater than the former experiment, making it essentially instantaneous. When compared to the solution of the advection-dispersion-reaction equation (ADRE) with the well-mixed reaction coefficient, the experiments and the particle-tracking simulations showed on the order of 20% to 40% less overall product, which is attributed to poor mixing. The poor mixing also leads to higher product concentrations on the edges of the mixing zones, which the particle

  16. Low Latency High Throughout Circular Asynchronous FIFO

    Institute of Scientific and Technical Information of China (English)

    XIAO Yong; ZHOU Runde

    2008-01-01

    This paper describes a circular first in first out (FIFO) and its protocols which have a very low la-tency while still maintaining high throughput. Unlike the existing serial FIFOs based on asynchronous micro-pipelines, this FIFO's cells communicate directly with the input and output ports through a common bus, which effectively eliminates the data movement from the input port to the output port, thereby reducing the latency and the power consumption. Furthermore, the latency does not increase with the number of FIFO stages. Single-track asynchronous protocols are used to simplify the FIFO controller design, with only three C-gates needed in each cell controller, which substantially reduces the area. Simulations with the TSMC 0.25 Ijm CMOS logic process show that the latency of the 4-stage FIFO is less than 581 ps and the throughput is higher than 2.2 GHz.

  17. Particle track densities in double drive tube 60009/10. [in plagioclase of lunar soil samples

    Science.gov (United States)

    Blanford, G. E.; Wood, G. C.; Mckay, D. S.

    1977-01-01

    Measurements are reported of particle track densities in grains from a suite of eleven samples from the Apollo 16 double drive tube 60009/10. All of the samples studied in 60009 show a clearly bimodal distribution of track densities in plagioclase. This bimodal distribution is interpreted to indicate a mixing of a relatively immature soil with a relatively mature soil. This mixing was not followed by any appreciable reworking which would have altered the distribution. The three lower samples in 60010 also show a bimodal distribution. However, the three uppermost samples show a unimodal distribution. The percentage of high track density plagioclase grains shows a good correlation with the other maturity indices of agglutinate content and the ferromagnetic resonance intensity.

  18. Two dimensional, electronic particle tracking in liquids with a graphene-based magnetic sensor array

    Science.gov (United States)

    Neumann, Rodrigo F.; Engel, Michael; Steiner, Mathias

    2016-07-01

    The investigation and control of liquid flow at the nanometer scale is a key area of applied research with high relevance to physics, chemistry, and biology. We introduce a method and a device that allows the spatial resolution of liquid flow by integrating an array of graphene-based magnetic (Hall) sensors that is used for tracking the movement of magnetic nanoparticles immersed in a liquid under investigation. With a novel device concept based on standard integration processes and experimentally verified material parameters, we numerically simulate the performance of a single sensor pixel, as well as the whole sensor array, for tracking magnetic nanoparticles having typical properties. The results demonstrate that the device enables (a) the detection of individual nanoparticles in the liquid with high accuracy and (b) the reconstruction of a particle's flow-driven trajectory across the integrated sensor array with sub-pixel precision as a function of time, in what we call the ``Magnetic nanoparticle velocimetry'' technique. Since the method does not rely on optical detection, potential lab-on-chip applications include particle tracking and flow analysis in opaque media at the sub-micron scale.The investigation and control of liquid flow at the nanometer scale is a key area of applied research with high relevance to physics, chemistry, and biology. We introduce a method and a device that allows the spatial resolution of liquid flow by integrating an array of graphene-based magnetic (Hall) sensors that is used for tracking the movement of magnetic nanoparticles immersed in a liquid under investigation. With a novel device concept based on standard integration processes and experimentally verified material parameters, we numerically simulate the performance of a single sensor pixel, as well as the whole sensor array, for tracking magnetic nanoparticles having typical properties. The results demonstrate that the device enables (a) the detection of individual

  19. Application of nuclear particle tracks: A scanning x-ray microscope

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, P.J.

    1991-09-30

    The scanning x-ray microscope (SXM) is a short-wavelength analog of a near-field optical-scanning microscope, promising spatial resolution of {approximately}100{angstrom} up to {approximately}5 keV x-ray energy. A portion of a synchrotron x-ray beam streams through an etched nuclear particle track in an opaque membrane and impinges on an object within the narrow stream. Scattered or transmitted x-rays are detected with a photon counter. The SXM is feasible because a useful number of synchrotron x-rays, even from a bend magnet, will stream through a small diameter pore. The properties and limitations of the SXM are discussed together with other submicroscopic applications of nuclear particle tracks. 14 refs., 8 figs., 1 tab.

  20. Single-sheet identification method of heavy charged particles using solid state nuclear track detectors

    Indian Academy of Sciences (India)

    M F Zaki; A Abdel-Naby; A Ahmed Morsy

    2007-08-01

    The theoretical and experimental investigations of the penetration of charged particles in matter played a very important role in the development of modern physics. Solid state nuclear track detectors have become one of the most important tools for many branches of science and technology. An attempt has been made to examine the suitability of the single-sheet particle identification technique in CR-39 and CN-85 polycarbonate by plotting track cone length vs. residual range for different heavy ions in these detectors. So, the maximum etchable ranges of heavy ions such as 93Nb, 86Kr and 4He in CR-39 and 4He and 132Xe in CN-85 polycarbonate have been determined. The ranges of these ions in these detectors have also been computed theoretically using the Henke–Benton program. A reasonably good agreement has been observed between the experimentally and theoretically computed values.

  1. Passive Target Tracking in Non-cooperative Radar System Based on Particle Filtering

    Institute of Scientific and Technical Information of China (English)

    LI Shuo; TAO Ran

    2006-01-01

    We propose a target tracking method based on particle filtering(PF) to solve the nonlinear non-Gaussian target-tracking problem in the bistatic radar systems using external radiation sources. Traditional nonlinear state estimation method is extended Kalman filtering (EKF), which is to do the first level Taylor series extension. It will cause an inaccuracy or even a scatter estimation result on condition that there is either a highly nonlinear target or a large noise square-error. Besides, Kalman filtering is the optimal resolution under a Gaussian noise assumption, and is not suitable to the non-Gaussian condition. PF is a sort of statistic filtering based on Monte Carlo simulation that is using some random samples (particles) to simulate the posterior probability density of system random variables. This method can be used in any nonlinear random system. It can be concluded through simulation that PF can achieve higher accuracy than the traditional EKF.

  2. Particle Data Management Software for 3DParticle Tracking Velocimetry and Related Applications – The Flowtracks Package

    Directory of Open Access Journals (Sweden)

    Yosef Meller

    2016-06-01

    Full Text Available The Particle Tracking Velocimetry (PTV community employs several formats of particle information such as position and velocity as function of time, i.e. trajectory data, as a result of diverging needs unmet by existing formats, and a number of different, mostly home-grown, codes for handling the data. Flowtracks is a Python package that provides a single code base for accessing different formats as a database, i.e. storing data and programmatically manipulating them using format-agnostic data structures. Furthermore, it offers an HDF5-based format that is fast and extensible, obviating the need for other formats. The package may be obtained from https://github.com/OpenPTV/postptv and used as-is by many fluid-dynamics labs, or with minor extensions adhering to a common interface, by researchers from other fields, such as biology and population tracking.

  3. Innovative molecular-based fluorescent nanoparticles for multicolor single particle tracking in cells

    Science.gov (United States)

    Daniel, Jonathan; Godin, Antoine G.; Palayret, Matthieu; Lounis, Brahim; Cognet, Laurent; Blanchard-Desce, Mireille

    2016-03-01

    Based on an original molecular-based design, we present bright and photostable fluorescent organic nanoparticles (FONs) showing excellent colloidal stability in various aqueous environments. Complementary near-infrared emitting and green emitting FONs were prepared using a simple, fast and robust protocol. Both types of FONs could be simultaneously imaged at the single-particle level in solution as well as in biological environments using a monochromatic excitation and a dual-color fluorescence microscope. No evidence of acute cytotoxicity was found upon incubation of live cells with mixed solutions of FONs, and both types of nanoparticles were found internalized in the cells where their motion could be simultaneously tracked at video-rate up to minutes. These fluorescent organic nanoparticles open a novel non-toxic alternative to existing nanoparticles for imaging biological structures, compatible with live-cell experiments and specially fitted for multicolor single particle tracking.

  4. Adaptation of multidimensional group particle tracking and particle wall-boundary condition model to the FDNS code

    Science.gov (United States)

    Chen, Y. S.; Farmer, R. C.

    1992-01-01

    A particulate two-phase flow CFD model was developed based on the FDNS code which is a pressure based predictor plus multi-corrector Navier-Stokes flow solver. Turbulence models with compressibility correction and the wall function models were employed as submodels. A finite-rate chemistry model was used for reacting flow simulation. For particulate two-phase flow simulations, a Eulerian-Lagrangian solution method using an efficient implicit particle trajectory integration scheme was developed in this study. Effects of particle-gas reaction and particle size change to agglomeration or fragmentation were not considered in this investigation. At the onset of the present study, a two-dimensional version of FDNS which had been modified to treat Lagrangian tracking of particles (FDNS-2DEL) had already been written and was operational. The FDNS-2DEL code was too slow for practical use, mainly because it had not been written in a form amenable to vectorization on the Cray, nor was the full three-dimensional form of FDNS utilized. The specific objective of this study was to reorder to calculations into long single arrays for automatic vectorization on the Cray and to implement the full three-dimensional version of FDNS to produce the FDNS-3DEL code. Since the FDNS-2DEL code was slow, a very limited number of test cases had been run with it. This study was also intended to increase the number of cases simulated to verify and improve, as necessary, the particle tracking methodology coded in FDNS.

  5. Preparation and quantification of radioactive particles for tracking hydrodynamic behavior in multiphase reactors.

    Science.gov (United States)

    Yunos, Mohd Amirul Syafiq Mohd; Hussain, Siti Aslina; Yusoff, Hamdan Mohamed; Abdullah, Jaafar

    2014-09-01

    Radioactive particle tracking (RPT) has emerged as a promising and versatile technique that can provide rich information about a variety of multiphase flow systems. However, RPT is not an off-the-shelf technique, and thus, users must customize RPT for their applications. This paper presents a simple procedure for preparing radioactive tracer particles created via irradiation with neutrons from the TRIGA Mark II research reactor. The present study focuses on the performance evaluation of encapsulated gold and scandium particles for applications as individual radioactive tracer particles using qualitative and quantitative neutron activation analysis (NAA) and an X-ray microcomputed tomography (X-ray Micro-CT) scanner installed at the Malaysian Nuclear Agency. PMID:24907683

  6. Optimization of microchannel plate multipliers for tracking minimum-ionizing particles

    Energy Technology Data Exchange (ETDEWEB)

    Oba, K.; Rehak, P.; Potter, D.

    1981-01-01

    The progress in development of special Microchannel Plates for particle tracking is reported. The requirements of (1) high spatial resolution; (2) high density of information; and (3) rate capability were found to be satisfied in a thick Microchannel Plate with a CsI coating operating in a focusing magnetic field. The measurements of the Microchannel Plate detection efficiency, gain and noise are presented for several detectors. The pictures of the passage and interaction of the high energy charged particles inside the detector are shown.

  7. Multi-view body tracking with a detector-driven hierarchical particle filter

    OpenAIRE

    Navarro, S.; López Méndez, Adolfo; Alcoverro Vidal, Marcel; Casas Pla, Josep Ramon

    2012-01-01

    In this paper we present a novel approach to markerless human motion capture that robustly integrates body part detections in multiple views. The proposed method fuses cues from multiple views to enhance the propagation and observation model of particle filtering methods aiming at human motion capture. We particularize our method to improve arm tracking in the publicly available IXMAS dataset. Our experiments show that the proposed method outperforms other state-ofthe- ar...

  8. Particle Filter with Integrated Voice Activity Detection for Acoustic Source Tracking

    Directory of Open Access Journals (Sweden)

    Anders M. Johansson

    2007-01-01

    Full Text Available In noisy and reverberant environments, the problem of acoustic source localisation and tracking (ASLT using an array of microphones presents a number of challenging difficulties. One of the main issues when considering real-world situations involving human speakers is the temporally discontinuous nature of speech signals: the presence of silence gaps in the speech can easily misguide the tracking algorithm, even in practical environments with low to moderate noise and reverberation levels. A natural extension of currently available sound source tracking algorithms is the integration of a voice activity detection (VAD scheme. We describe a new ASLT algorithm based on a particle filtering (PF approach, where VAD measurements are fused within the statistical framework of the PF implementation. Tracking accuracy results for the proposed method is presented on the basis of synthetic audio samples generated with the image method, whereas performance results obtained with a real-time implementation of the algorithm, and using real audio data recorded in a reverberant room, are published elsewhere. Compared to a previously proposed PF algorithm, the experimental results demonstrate the improved robustness of the method described in this work when tracking sources emitting real-world speech signals, which typically involve significant silence gaps between utterances.

  9. Confocal microscopy in the analysis of the etched nuclear particle tracks in polymers

    Energy Technology Data Exchange (ETDEWEB)

    Jakes, J.; Schraube, H. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Inst. fuer Strahlenschutz; Gais, P. [GSF-Neuherberg (Germany). Inst. fuer Pathologie

    1995-01-01

    The possibility of the morphometric analysis of etched tracks, induced by protons and alpha particles in the organic polymer allyl diglycol carbonate (CR-39), using the confocal scanning laser microscope (CSLM), was studied. The detectors were investigated in two groups of irradiation experiments, namely: (a) irradiated with mono-energetic neutrons of energy 1.2 MeV, (b) exposed to the alpha radiation from {sup 222}Rn and its progeny. Both groups were irradiated at normal incidence. Radiation-induced latent tracks were electrochemically etched, and their morphometric parameters were investigated in the reflection mode by using the 488-nm spectral line of an argon ion laser. A constant number of up to 200 optical sections in Z-scan mode was taken through each selected etched track at vertical spacings of 0.642 {mu}m. Successive reconstructions of Z-sections were used to determine the following parameters: the mead radius of the opening channel, the maximum diameter and the length of the track, and the angle of the track wall to the surface of the sample. (author).

  10. Ground Moving Target Tracking with VS-IMM Using Mean Shift Unscented Particle Filter

    Institute of Scientific and Technical Information of China (English)

    GAO Caicai; CHEN Wei

    2011-01-01

    In order to track ground moving target,a variable structure interacting multiple model (VS-IMM)using mean shift unscented particle filter(MS-UPF)is proposed in this paper.In model-conditioned filtering,sample particles obtained from the unscented particle filter are moved towards the maximal posterior density estimation of the target state through mean shift.On the basis of stop model in VS-1MM,hide model is proposed.Once the target is obscured by terrain,the prediction at prior time is used instead of the measurement at posterior time; in addition,the road molel set used is not changed.A ground moving target indication(GMTI)radar is employed in three common simulation scenarios of ground target:entering or leaving a road,crossing a junction and no measurement.Two evaluation indexes,root mean square error(RMSE)and average normalized estimation error squared(ANEES),are used.The results indicate that when the road on which the target moving changes,the tracking accuracy is effectively improved in the proposed algorithm.Moreover,track interruption could be avoided if the target is moving too slowly or masked by terrain.

  11. Asynchronous Variational Integrators

    OpenAIRE

    Lew, A.; Marsden, J. E.; Ortiz, M.; West, M

    2003-01-01

    We describe a new class of asynchronous variational integrators (AVI) for nonlinear elastodynamics. The AVIs are distinguished by the following attributes: (i) The algorithms permit the selection of independent time steps in each element, and the local time steps need not bear an integral relation to each other; (ii) the algorithms derive from a spacetime form of a discrete version of Hamilton’s variational principle. As a consequence of this variational structure, the algorith...

  12. Text Mining: (Asynchronous Sequences

    Directory of Open Access Journals (Sweden)

    Sheema Khan

    2014-12-01

    Full Text Available In this paper we tried to correlate text sequences those provides common topics for semantic clues. We propose a two step method for asynchronous text mining. Step one check for the common topics in the sequences and isolates these with their timestamps. Step two takes the topic and tries to give the timestamp of the text document. After multiple repetitions of step two, we could give optimum result.

  13. A computational framework for particle and whole cell tracking applied to a real biological dataset.

    Science.gov (United States)

    Yang, Feng Wei; Venkataraman, Chandrasekhar; Styles, Vanessa; Kuttenberger, Verena; Horn, Elias; von Guttenberg, Zeno; Madzvamuse, Anotida

    2016-05-24

    Cell tracking is becoming increasingly important in cell biology as it provides a valuable tool for analysing experimental data and hence furthering our understanding of dynamic cellular phenomena. The advent of high-throughput, high-resolution microscopy and imaging techniques means that a wealth of large data is routinely generated in many laboratories. Due to the sheer magnitude of the data involved manual tracking is often cumbersome and the development of computer algorithms for automated cell tracking is thus highly desirable. In this work, we describe two approaches for automated cell tracking. Firstly, we consider particle tracking. We propose a few segmentation techniques for the detection of cells migrating in a non-uniform background, centroids of the segmented cells are then calculated and linked from frame to frame via a nearest-neighbour approach. Secondly, we consider the problem of whole cell tracking in which one wishes to reconstruct in time whole cell morphologies. Our approach is based on fitting a mathematical model to the experimental imaging data with the goal being that the physics encoded in the model is reflected in the reconstructed data. The resulting mathematical problem involves the optimal control of a phase-field formulation of a geometric evolution law. Efficient approximation of this challenging optimal control problem is achieved via advanced numerical methods for the solution of semilinear parabolic partial differential equations (PDEs) coupled with parallelisation and adaptive resolution techniques. Along with a detailed description of our algorithms, a number of simulation results are reported on. We focus on illustrating the effectivity of our approaches by applying the algorithms to the tracking of migrating cells in a dataset which reflects many of the challenges typically encountered in microscopy data. PMID:26948574

  14. Nanoparticle transport in heterogeneous porous media with particle tracking numerical methods

    Science.gov (United States)

    Pham, Ngoc H.; Papavassiliou, Dimitrios V.

    2016-08-01

    In this article, transport and retention of nanoparticles that flow in suspension through packed beds with unconsolidated spheres and through consolidated Berea sandstone are numerically explored. The surfaces exhibit electrical charge heterogeneity where particles can deposit blocking the surrounding surface deposition sites. The lattice Boltzmann method with Lagrangian particle tracking are the techniques employed. Four ideal patterns of surface charge heterogeneity are adopted for the packed sphere beds, while a real distribution of charge heterogeneity is determined for the Berea core through micro-CT image segmentation. It is found that particle breakthrough curves do not reach a plateau, unless the pore surfaces are completely saturated. Surface saturation also enhances particle propagation because of the surface blocking mechanism, reducing the effective particle deposition rate. In addition, surface saturation mitigates the effect of the pattern of heterogeneity on particle retention, which might be pronounced when blocking is not taken into account. It is also observed from the case of Berea core that the heterogeneity of the mineralogical surfaces disturbs particle transport depending on the physicochemical properties of the surfaces. Likewise, similarity of the mineralogical surface properties is a prerequisite for the commonly used patch-wise model with Langmuirian blocking to reproduce nanoparticle breakthrough in such porous media.

  15. A novel Al 2O 3 fluorescent nuclear track detector for heavy charged particles and neutrons

    Science.gov (United States)

    Akselrod, G. M.; Akselrod, M. S.; Benton, E. R.; Yasuda, N.

    2006-06-01

    A novel Al2O3 fluorescent nuclear track detector (FNTD), recently developed by Landauer, Inc., has demonstrated sensitivity and functionality superior to that of existing nuclear track detectors. The FNTD is based on single crystals of aluminum oxide doped with carbon and magnesium, and having aggregate oxygen vacancy defects (Al2O3:C,Mg). Radiation-induced color centers in the new material have an absorption band at 620 nm and produce fluorescence at 750 nm with a high quantum yield and a short, 75 ± 5 ns, fluorescence lifetime. Non-destructive readout of the detector is performed using a confocal fluorescence microscope. Scanning of the three-dimensional spatial distribution of fluorescence intensity along the track of a heavy charged particle (HCP) permits reconstruction of particle trajectories through the crystal and the LET can be determined as a function of distance along the trajectory based on the fluorescence intensity. Major advantages of Al2O3:C,Mg FNTD over conventionally processed CR-39 plastic nuclear track detector include superior spatial resolution, a wider range of LET sensitivity, no need for post-irradiation chemical processing of the detector and the capability to anneal and reuse the detector. Preliminary experiments have demonstrated that the material possesses a low-LET threshold of <1 keV/μm, does not saturate at LET in water as high as 1800 keV/μm, and is capable of irradiation to fluences in excess of 106 cm-2 without saturation (track overlap).

  16. Tracking down the links between charged particles and biological response: A UK perspective

    Science.gov (United States)

    Hill, Mark A.

    2013-07-01

    The UK has a long history of radiobiology research into charged particles, with interest likely to expand in the coming years following the recent government announcement of £250 million to build two proton beam therapy facilities in the UK. A brief overview of research and facilities past and present with respect to radiation protection and oncology along with biological consequences and underlying mechanisms will be presented and discussed. Increased knowledge of the mechanisms underpinning the radiation action on biological systems is important in understanding, not only the risks associated with exposure, but also in optimising radiotherapy treatment of cancer. Ionizing radiation is always in the form of structure tracks which are a unique characteristic of ionizing radiation alone producing damage grossly different and far more biologically effective than endogenous damage. The track structure is the prime determinant of biological response to DNA, with charged particles of increasing LET leading to an increase in the frequency and complexity of clustered DNA damage. High-LET particles will also produce non-homogeneous dose distribution through a cell nucleus resulting in correlated DNA breaks along the path of the particle and an increase in the probability of complex chromosomal rearrangements. However it is now well established that there is variety of phenomena that do not conform to the conventional paradigm of targeted radiobiology, but there is insufficient evidence to assess the implications of these non-targeted effects for radiotherapy or relevance to risk for human health.

  17. Real-time optical imaging and tracking of micron-sized particles

    Science.gov (United States)

    Qian, Feng; Song, Qi; Tien, En-kuang; Kalyoncu, Salih K.; Boyraz, Ozdal

    2009-12-01

    We report real-time imaging and dynamics monitoring of micrometer predefined and random sized particles by time-space-wavelength mapping technology using a single-detector. Experimentally, we demonstrate real-time line imaging of a 5 μm polystyrene microsphere, glass powder particles and patterns such as fingerprints with up to 5 μm resolution at 1 line/50 ns capture rate. By using the same setup, real-time displacement tracking of micrometer-size glass particles with 50 ns temporal resolution and up to 5 μm spatial resolution is achieved. We also show that existing correlation spectroscopy algorithms can be adopted to extract dynamic information in a complex environment.

  18. Analysis of Base-Case Particle Tracking Results of the Base-Case Flow Fields (ID:U0160)

    Energy Technology Data Exchange (ETDEWEB)

    C.K. Ho

    2000-01-19

    The purpose of this analysis is to provide insight into the unsaturated-zone (UZ) subsystem performance through particle tracking analyses of the base-case flow fields. The particle tracking analyses will not be used directly in total-system performance-assessment (TSPA) calculations per se. The objective of this activity is to evaluate the transport of radionuclides through the unsaturated zone and to determine how different system parameters such as matrix diffusion, sorption, water-table rise, and perched water influence the transport to the water table. Plots will be generated to determine normalized cumulative breakthrough curves for selected radionuclides. The scope of this work is limited to the particle tracking analyses of ''base-case'' flow fields that are to be used by the code FEHM (Finite Element Heat and Mass; Zyvoloski 1997) for particle tracking simulations in ''Total System Performance Assessment-Site Recommendation Report'' (TSPA-SR).

  19. Impact of electron irradiation on particle track etching response in polyallyl diglycol carbonate (PADC)

    Indian Academy of Sciences (India)

    R Mishra; S P Tripathy; A Kulshrestha; A Srivastava; S Ghosh; K K Dwivedi; D T Khathing; M Müller; D Fink

    2000-05-01

    In the present work, attempts have been made to investigate the modification in particle track etching response of polyallyl diglycol carbonate (PADC) due to impact of 2 MeV electrons. PADC samples pre-irradiated to 1, 10, 20, 40, 60, 80 and 100 Mrad doses of 2 MeV electrons were further exposed to 140 MeV 28Si beam and dose-dependent track registration properties of PADC have been studied. Etch-rate values of the PADC irradiated to 100 Mrad dose electron was found to increase by nearly 4 times that of pristine PADC. The electron irradiation has promoted chain scissioning in PADC, thereby converting the polymer into an easily etchable polymer. Moreover, the etching response and the detection efficiency were found to improve by electron irradiation. Scanning electron microscopy of etched samples further revealed the surface damage in these irradiated PADCs

  20. Dual-Channel Particle Filter Based Track-Before-Detect for Monopulse Radar

    Directory of Open Access Journals (Sweden)

    Fei Cai

    2014-01-01

    Full Text Available A particle filter based track-before-detect (PF-TBD algorithm is proposed for the monopulse high pulse repetition frequency (PRF pulse Doppler radar. The actual measurement model is adopted, in which the range is highly ambiguous and the sum and difference channels exist in parallel. A quantization method is used to approximate the point spread function to reduce the computation load. The detection decisions of the PF-TBD are fed to a binary integrator to further improve the detection performance. Simulation results show that the proposed algorithm can detect and track the low SNR target efficiently. The detection performance is improved significantly for both the single frame and the multiframe detection compared with the classical detector. A performance comparison with the PF-TBD using sum channel only is also supplied.

  1. Direction Tracking of Multiple Moving Targets Using Quantum Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Gao Hongyuan

    2016-01-01

    Full Text Available Based on weighted signal covariance (WSC matrix and maximum likelihood (ML estimation, a directionof-arrival (DOA estimation method of multiple moving targets is designed and named as WSC-ML in the presence of impulse noise. In order to overcome the shortcoming of the multidimensional search cost of maximum likelihood estimation, a novel continuous quantum particle swarm optimization (QPSO is proposed for this continuous optimization problem. And a tracking method of multiple moving targets in impulsive noise environment is proposed and named as QPSO-WSC-ML. Later, we make use of rank-one updating to update the weighted signal covariance matrix of WSC-ML. Simulation results illustrate the proposed QPSO-WSC-ML method is efficient and robust for the direction tracking of multiple moving targets in the presence of impulse noise.

  2. Interpolating cathode pad readout in gas proportional detectors for high multiplicity particle tracks

    Energy Technology Data Exchange (ETDEWEB)

    Yu, B.; Radeka, V.; Smith, G.C.; O`Brien, E.

    1992-02-01

    Experiments which are planned for the Superconducting Super Collider and the Relativistic Heavy Ion Collider will involve interactions in which detectors will need to identify and localize hundreds or even thousands of particle tracks simultaneously. Most types of conventional position sensitive, proportional detectors with projective geometry are not able to unravel the individual tracks in these environments. We have been investigating several forms of sub-divided cathode readout to address this problem. We report here on geometric charge division using chevron shaped cathode pads which lie in rows underneath each anode wire. Investigations have quantified the non-linear effects due to avalanche angular localization, and how these become negligible with proper design of the pad. Differential nm-linearity of {plus_minus}5%, and position resolution in the region of 50{mu}m rms, have been achieved.

  3. Interpolating cathode pad readout in gas proportional detectors for high multiplicity particle tracks

    Energy Technology Data Exchange (ETDEWEB)

    Yu, B.; Radeka, V.; Smith, G.C.; O' Brien, E.

    1992-02-01

    Experiments which are planned for the Superconducting Super Collider and the Relativistic Heavy Ion Collider will involve interactions in which detectors will need to identify and localize hundreds or even thousands of particle tracks simultaneously. Most types of conventional position sensitive, proportional detectors with projective geometry are not able to unravel the individual tracks in these environments. We have been investigating several forms of sub-divided cathode readout to address this problem. We report here on geometric charge division using chevron shaped cathode pads which lie in rows underneath each anode wire. Investigations have quantified the non-linear effects due to avalanche angular localization, and how these become negligible with proper design of the pad. Differential nm-linearity of {plus minus}5%, and position resolution in the region of 50{mu}m rms, have been achieved.

  4. Development of a scintillation-fiber detector for real-time particle tracking

    Science.gov (United States)

    Lo Presti, D.; Bonanno, D. L.; Longhitano, F.; Pugliatti, C.; Russo, G. V.; Aiello, S.; Cirrone, G. A. P.; Giordano, V.; Leonora, E.; Randazzo, N.; Romano, F.; Russo, M.; Sipala, V.; Stancampiano, C.; Reito, S.

    2013-04-01

    The prototype of the OFFSET (Optical Fiber Folded Scintillating Extended Tracker) tracker is presented. It exploits a novel system for particle tracking, designed to achieve real-time imaging, large detection areas, and a high spatial resolution especially suitable for use in medical diagnostics. The main results regarding the system architecture have been used as a demonstration of the technique which has been patented by the Istituto Nazionale di Fisica Nucleare (INFN). The prototype of this tracker, presented in this paper, has a 20 × 20 cm2 sensitive area, consisting of two crossed ribbons of 500 micron square scintillating fibers. The track position information is extracted in real time in an innovative way, using a reduced number of read-out channels to obtain very large detection area with moderate enough costs and complexity. The performance of the tracker was investigated using beta sources, cosmic rays, and a 62 MeV proton beam.

  5. Development of a scintillation-fiber detector for real-time particle tracking

    International Nuclear Information System (INIS)

    The prototype of the OFFSET (Optical Fiber Folded Scintillating Extended Tracker) tracker is presented. It exploits a novel system for particle tracking, designed to achieve real-time imaging, large detection areas, and a high spatial resolution especially suitable for use in medical diagnostics. The main results regarding the system architecture have been used as a demonstration of the technique which has been patented by the Istituto Nazionale di Fisica Nucleare (INFN). The prototype of this tracker, presented in this paper, has a 20 × 20 cm2 sensitive area, consisting of two crossed ribbons of 500 micron square scintillating fibers. The track position information is extracted in real time in an innovative way, using a reduced number of read-out channels to obtain very large detection area with moderate enough costs and complexity. The performance of the tracker was investigated using beta sources, cosmic rays, and a 62 MeV proton beam.

  6. Embedded Analytical Solutions Improve Accuracy in Convolution-Based Particle Tracking Models using Python

    Science.gov (United States)

    Starn, J. J.

    2013-12-01

    Particle tracking often is used to generate particle-age distributions that are used as impulse-response functions in convolution. A typical application is to produce groundwater solute breakthrough curves (BTC) at endpoint receptors such as pumping wells or streams. The commonly used semi-analytical particle-tracking algorithm based on the assumption of linear velocity gradients between opposing cell faces is computationally very fast when used in combination with finite-difference models. However, large gradients near pumping wells in regional-scale groundwater-flow models often are not well represented because of cell-size limitations. This leads to inaccurate velocity fields, especially at weak sinks. Accurate analytical solutions for velocity near a pumping well are available, and various boundary conditions can be imposed using image-well theory. Python can be used to embed these solutions into existing semi-analytical particle-tracking codes, thereby maintaining the integrity and quality-assurance of the existing code. Python (and associated scientific computational packages NumPy, SciPy, and Matplotlib) is an effective tool because of its wide ranging capability. Python text processing allows complex and database-like manipulation of model input and output files, including binary and HDF5 files. High-level functions in the language include ODE solvers to solve first-order particle-location ODEs, Gaussian kernel density estimation to compute smooth particle-age distributions, and convolution. The highly vectorized nature of NumPy arrays and functions minimizes the need for computationally expensive loops. A modular Python code base has been developed to compute BTCs using embedded analytical solutions at pumping wells based on an existing well-documented finite-difference groundwater-flow simulation code (MODFLOW) and a semi-analytical particle-tracking code (MODPATH). The Python code base is tested by comparing BTCs with highly discretized synthetic steady

  7. Track Reconstruction and Performance of DRIFT Directional Dark Matter Detectors using Alpha Particles

    CERN Document Server

    Burgos, S; Ghag, C; Gold, M; Kudryavtsev, V A; Lawson, T B; Loomba, D; Majewski, P; McMillan, J E; Muna, D; Murphy, A StJ; Nicklin, G G; Paling, S M; Petkov, A; Plank, S J S; Robinson, M; Sanghi, N; Smith, N J T; Snowden-Ifft, D P; Spooner, N J C; Sumner, T J; Turk, J; Tziaferi, T

    2007-01-01

    First results are presented from an analysis of data from the DRIFT-IIa and DRIFT-IIb directional dark matter detectors at Boulby Mine in which alpha particle tracks were reconstructed and used to characterise detector performance--an important step towards optimising directional technology. The drift velocity in DRIFT-IIa was [59.3 +/- 0.2 (stat) +/- 7.5 (sys)] m/s based on an analysis of naturally-occurring alpha-emitting background. The drift velocity in DRIFT-IIb was [57 +/- 1 (stat) +/- 3 (sys)] m/s determined by the analysis of alpha particle tracks from a Po-210 source. 3D range reconstruction and energy spectra were used to identify alpha particles from the decay of Rn-222, Po-218, Rn-220 and Po-216. This study found that (22 +/- 2)% of Po-218 progeny (from Rn-222 decay) are produced with no net charge in 40 Torr CS2. For Po-216 progeny (from Rn-220 decay) the uncharged fraction is (100 +0 -35)%.

  8. A better understanding of biomass co-firing by developing an advanced non-spherical particle tracking model

    DEFF Research Database (Denmark)

    Yin, Chungen; Rosendahl, Lasse Aistrup; Kær, Søren Knudsen;

    2004-01-01

    . To better understand biomass co-firing and therefore improve the design for co-firing biomass in wall-fired burners, the most commonly used spherical particle shape assumption is not used here, which may deviate a lot from reality for big biomass particles. A sphere gives a minimum in terms of the surface-area-to-volume......-gradient force. Since the drag and lift forces are both shape factor- and orientation-dependent, coupled particle rotation equations are resolved to update particle orientation. In the reaction of biomass particles, the actual particle surface area available and the average oxygen mass flux at particle surface...... ratio and thus experiences a totally different motion and reaction as a non-spherical particle. Therefore, an advanced non-spherical particle-tracking model is developed to calculate the motion and reaction of nonspherical biomass particles. The biomass particles are assumed as solid or hollow cylinders...

  9. Operator tracking system using particle filter for skill evaluation in nuclear power plant control room

    International Nuclear Information System (INIS)

    This article proposes an automated operator tracking system by the use of particle filter and image processing technology to help operator skill evaluation in nuclear power plant operator training facilities. In each of the control room of the training facilities, a full-scope plant simulator with mock-up control panels are used for real-time operator training. At this point, the operators' behaviors and plant's events are recorded as video-log and event-log, by a multi-media recording system to evaluate operators' skills at training review meetings in which the instructors and trainees discuss each of their action during the training process. Multiple cameras that are placed on the control room ceiling are used in the recording system. However, the views from these cameras are limited and therefore it is not possible to thoroughly check how each of the operator approaches the target panel within an appropriate timing that corresponds to the plant's event. For example, the instructors have to estimate operators' real-world position from the views; and in some cases other operators might conceal the target operators from the cameras. The purpose of the proposed system is to help checking whether the position and timing of each operator is appropriate during each event or alarm occurrence, by tracking the operators from the recorded video. To achieve this objective, the real-time image processing technology is newly introduced in this study, where particle filter is one of convenient algorithms for operator tracking. In this algorithm, the main issue is how to recognize multiple operators from the background and to get their positions within the coordinates of the control room. For this purpose, one 3-D particle filter is used for each operator wearing colored vests and the similarity calculation algorithm is based on color histogram. The particles are directly placed inside the control room. By converting the particle coordinates into camera coordinates and taking

  10. Improved estimation of anomalous diffusion exponents in single-particle tracking experiments

    Science.gov (United States)

    Kepten, Eldad; Bronshtein, Irena; Garini, Yuval

    2013-05-01

    The mean square displacement is a central tool in the analysis of single-particle tracking experiments, shedding light on various biophysical phenomena. Frequently, parameters are extracted by performing time averages on single-particle trajectories followed by ensemble averaging. This procedure, however, suffers from two systematic errors when applied to particles that perform anomalous diffusion. The first is significant at short-time lags and is induced by measurement errors. The second arises from the natural heterogeneity in biophysical systems. We show how to estimate and correct these two errors and improve the estimation of the anomalous parameters for the whole particle distribution. As a consequence, we manage to characterize ensembles of heterogeneous particles even for rather short and noisy measurements where regular time-averaged mean square displacement analysis fails. We apply this method to both simulations and in vivo measurements of telomere diffusion in 3T3 mouse embryonic fibroblast cells. The motion of telomeres is found to be subdiffusive with an average exponent constant in time. Individual telomere exponents are normally distributed around the average exponent. The proposed methodology has the potential to improve experimental accuracy while maintaining lower experimental costs and complexity.

  11. Proceedings of the 3. conference: Particle track membranes and their applications

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    The materials of the 3rd conference on Particle Track Membranes and Theirs Applications present actual state of art in the topic. The leading world institutions have presented their works on the technology of PTM production by interaction of ion beams with polymeric foils. The broad spectrum of PTM membranes have been shown, their properties have been described and their applicability discussed. A number of possible applications of PTM and also already realized in industry, medicine, biology and physical investigations have been presented. 29 lectures have been made in the course of conference.

  12. Brightness through Local Constraint-LNA-Enhanced FIT Hybridization Probes for In Vivo Ribonucleotide Particle Tracking

    DEFF Research Database (Denmark)

    Hövelmann, Felix; Gaspar, Imre; Loibl, Simon;

    2014-01-01

    ) probes that combine the high enhancement of fluorescence upon hybridization with the high brightness required to allow tracking of individual ribonucleotide particles (RNPs). In our design, a single thiazole orange (TO) intercalator dye is linked as a nucleobase surrogate and an adjacent locked nucleic......Imaging the dynamics of RNA in living cells is usually performed by means of transgenic approaches that require modification of RNA targets and cells. Fluorogenic hybridization probes would also allow the analysis of wild-type organisms. We developed nuclease-resistant DNA forced intercalation (FIT...

  13. Potential of Thin Films for use in Charged Particle Tracking Detectors

    CERN Document Server

    Metcalfe, J; Murphy, J; Quevedo, M; Smith, L; Alvarado, J; Gnade, B; Takai, H

    2014-01-01

    Thin Film technology has widespread applications in everyday electronics, notably Liquid Crystal Display screens, solar cells, and organic light emitting diodes. We explore the potential of this technology as charged particle radiation tracking detectors for use in High Energy Physics experiments such as those at the Large Hadron Collider or the Relativistic Heavy Ion Collider. Through modern fabrication techniques, a host of semiconductor materials are available to construct thin, flexible detectors with integrated electronics with pixel sizes on the order of a few microns. We review the material properties of promising candidates, discuss the potential benefits and challenges associated with this technology, and review previously demonstrated applicability as a neutron detector.

  14. A Framework for Sediment Particle Tracking via Radio Frequency IDentification (RFID)

    Science.gov (United States)

    Tsakiris, Achilleas; Papanicolaou, Thanos; Abban, Benjamin

    2016-04-01

    The study of sedimentary and morphodynamic processes in riverine environments has recently been shifting from the traditional Eulerian, static perspective to a Lagrangian perspective, which considers the movement characteristics of the individual transported particles, such as their travel and resting distance and time. The Lagrangian framework, in turn allows to better study processes such as bedload particle diffusion, erosion and deposition within a river reach, to more accurately predict bedload fluxes especially through the use of stochastic Discrete Particle models. A technology that goes hand-in-hand with this Lagrangian perspective is Radio Frequency IDentification (RFID), which has been recently applied for tracking the movement of tagged sediment particles within the river continuum. RFID allows the wireless, bidirectional exchange of information between a base station, known as the reader, with a typically large number of transponders (or tags) via an (excitation) antenna. RFID allows essentially the unique, wireless detection and identification of a transponder over a distance. The goal of this study is to further enhance the utility of RFID in riverine applications by developing a framework that allows extracting the 3D location of RFID tagged sediment particles in nearly real-time. To address the goal of this coupled theoretical and experimental study, a semi-theoretical approach based on antenna inductive coupling was combined with experimental measurements for developing a relationship that provides an estimate of the distance between a tagged particle and the antenna using the Return Signal Strength Indication (RSSI). The RSSI quantifies the magnetic energy transmitted from the transponder to the antenna. The RFID system used in this study was a passive, Low-Frequency (LF) system, which ensured that the LF radio waves could penetrate through the river bed material. The RSSI of the signal transmitted from each transponder was measured with an

  15. Guidelines for the fitting of anomalous diffusion mean square displacement graphs from single particle tracking experiments.

    Directory of Open Access Journals (Sweden)

    Eldad Kepten

    Full Text Available Single particle tracking is an essential tool in the study of complex systems and biophysics and it is commonly analyzed by the time-averaged mean square displacement (MSD of the diffusive trajectories. However, past work has shown that MSDs are susceptible to significant errors and biases, preventing the comparison and assessment of experimental studies. Here, we attempt to extract practical guidelines for the estimation of anomalous time averaged MSDs through the simulation of multiple scenarios with fractional Brownian motion as a representative of a large class of fractional ergodic processes. We extract the precision and accuracy of the fitted MSD for various anomalous exponents and measurement errors with respect to measurement length and maximum time lags. Based on the calculated precision maps, we present guidelines to improve accuracy in single particle studies. Importantly, we find that in some experimental conditions, the time averaged MSD should not be used as an estimator.

  16. Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow.

    Science.gov (United States)

    Kim, Jin-Tae; Kim, David; Liberzon, Alex; Chamorro, Leonardo P

    2016-02-27

    3D-PTV is a quantitative flow measurement technique that aims to track the Lagrangian paths of a set of particles in three dimensions using stereoscopic recording of image sequences. The basic components, features, constraints and optimization tips of a 3D-PTV topology consisting of a high-speed camera with a four-view splitter are described and discussed in this article. The technique is applied to the intermediate flow field (5 particles as well as curvature of the flow path, which are obtained from the Frenet-Serret equation. Estimation of the 3D velocity and turbulence fields around the jet core axis at a cross-plane located at ten diameters downstream of the jet is compared with literature, and the power spectrum of the large-scale streamwise velocity motions is obtained at various radial distances from the jet core.

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

    Directory of Open Access Journals (Sweden)

    Wen-Chang Cheng

    2012-12-01

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

  18. Numerical simulation of gas-liquid-solid flows using a combined front tracking and discrete particle method

    NARCIS (Netherlands)

    Sint Annaland, van M.; Deen, N.G.; Kuipers, J.A.M.

    2005-01-01

    In this paper a hybrid model is presented for the numerical simulation of gas¿liquid¿solid flows using a combined front tracking (FT) and discrete particle (DP) approach applied for, respectively, dispersed gas bubbles and solid particles present in the continuous liquid phase. The hard sphere DP mo

  19. In Situ Particle Tracking around kW Sized Wind Turbines

    Science.gov (United States)

    Brownstein, Ian; Dabiri, John

    2015-11-01

    Laboratory studies of model wind turbines are typically unable to match both the Reynolds number (Re) and tip speed ratio (TSR) of full-scale wind turbines. In order to match both relevant parameters, a quantitative flow visualization method was developed to take in situ measurements of the flow around full-scale wind turbines. The apparatus constructed was able to seed an approximately 9mx9mx5m volume in the wake of the turbine using artificial snow. Quantitative results were obtained by tracking the evolution of the snow using particle tracking algorithms. As a step toward full 3D-PTV measurements, results will be presented in which a 2D measurement is taken with a single camera positioned at the base of the turbine looking upward. The resulting tracking is therefore integrated in the span-wise direction. This method is demonstrated through a comparative study of a five-bladed VAWT producing power in different wind conditions at the Field Laboratory for Optimized Wind Energy (FLOWE) in Lancaster, CA. Future work to expand this method to 3D-PTV is also discussed.

  20. Principles and biophysical applications of single particle super-localization and rotational tracking

    Science.gov (United States)

    Gu, Yan

    While conventional Single Particle Tracking (SPT) techniques acquire 2D or 3D trajectories of particle probes, we have developed Single Particle Orientation and Rotational Tracking (SPORT) techniques to extract orientation and rotational information. Combined with DIC microscopy, the SPORT technique has been applied in biophysical studies, including membrane diffusion and intracellular transport. The rotational dynamics of nanoparticle vectors on live cell membranes was recorded and its influence on the fate of these nanoparticle vectors was elucidated. The rotational motions of gold nanorods with various surface modifiers were tracked continuously at a temporal resolution of 5 ms under a DIC microscope. We found that the rotational behaviors of gold nanorod vectors are strongly related to their surface charge, specific surface functional groups, and the availability of receptors on cell membranes. The study of rotational Brownian motion of nanoparticles on cell membranes will lead to a better understanding of the mechanisms of drug delivery and provide guidance in designing surface modification strategies for drug delivery vectors under various circumstances. To characterize the rotation mode of surface functionalized gold nanorods on cell membranes, the SPORT technique is combined with the correlation analysis of the bright and dark DIC intensities. The unique capabilities of visualizing and understanding rotational motions of functionalized nanoparticles on live cell membranes allow us to correlate rotational and translational dynamics in unprecedented detail and provide new insights for complex membrane processes, including electrostatic interactions, ligand-receptor binding, and lateral (confined and hopping) diffusion of membrane receptors. Surface-functionalized nanoparticles interact with the membrane in fundamentally different ways and exhibit distinct rotational modes. The early events of particle-membrane approach and attachment are directly visualized

  1. Principles and biophysical applications of single particle super-localization and rotational tracking

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Yan [Iowa State Univ., Ames, IA (United States)

    2013-01-01

    While conventional Single Particle Tracking (SPT) techniques acquire 2D or 3D trajectories of particle probes, we have developed Single Particle Orientation and Rotational Tracking (SPORT) techniques to extract orientation and rotational information. Combined with DIC microscopy, the SPORT technique has been applied in biophysical studies, including membrane diffusion and intracellular transport. The rotational dynamics of nanoparticle vectors on live cell membranes was recorded and its influence on the fate of these nanoparticle vectors was elucidated. The rotational motions of gold nanorods with various surface modifiers were tracked continuously at a temporal resolution of 5 ms under a DIC microscope. We found that the rotational behaviors of gold nanorod vectors are strongly related to their surface charge, specific surface functional groups, and the availability of receptors on cell membranes. The study of rotational Brownian motion of nanoparticles on cell membranes will lead to a better understanding of the mechanisms of drug delivery and provide guidance in designing surface modification strategies for drug delivery vectors under various circumstances. To characterize the rotation mode of surface functionalized gold nanorods on cell membranes, the SPORT technique is combined with the correlation analysis of the bright and dark DIC intensities. The unique capabilities of visualizing and understanding rotational motions of functionalized nanoparticles on live cell membranes allow us to correlate rotational and translational dynamics in unprecedented detail and provide new insights for complex membrane processes, including electrostatic interactions, ligand-receptor binding, and lateral (confined and hopping) diffusion of membrane receptors. Surface-functionalized nanoparticles interact with the membrane in fundamentally different ways and exhibit distinct rotational modes. The early events of particle-membrane approach and attachment are directly visualized

  2. Investigating the role of vibrational excitation in simulating charged-particle tracks in liquid pyrimidine

    Science.gov (United States)

    Brunger, Michael J.; Ratnavelu, Kuru; Buckman, Stephen J.; Jones, Darryl B.; Muñoz, Antonio; Blanco, Francisco; García, Gustavo

    2016-03-01

    We report on our results of a study into the sensitivity of charged-particle (electron) track simulations in liquid pyrimidine, to the vibrational cross sections and vibrational energy loss distribution function employed in those simulations. We achieve this by repeating the earlier investigation of Fuss et al. [J. Appl. Phys. 117, 214701 (2015)], but now incorporating more accurate data for the vibrational integral cross sections and the energy loss distribution function that have recently become available. We find that while changes in absorbed dose or particle range are quite minor, due to the energy transferred via vibrational excitations being low in comparison to that for other processes such as ionisation, at the very end of the tracks, where non-ionizing interactions dominate, the significantly large numbers of vibrational excitation processes increases the electrons' ability to induce other effects (e.g. sample heating, bond breaking and radical formation) that might cause damage. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.

  3. Development of multi-spectral three-dimensional micro particle tracking velocimetry

    Science.gov (United States)

    Tien, Wei-Hsin

    2016-08-01

    The color-coded 3D micro particle tracking velocimetry system (CC3DμPTV) is a volumetric velocimetry technique that uses the defocusing digital particle image velocimetry (DDPIV) approach to reconstruct the 3D location of the particle. It is suited for microscopic flow visualization because of the single camera configuration. However, several factors limit the performance of the system. In this study, the limitation of the CC3DμPTV is discussed in detail and a new concept of a multi-camera 3D μ-PTV system is proposed to improve the performance of the original CC3DμPTV system. The system utilizes two dichroic beam splitters to separate the incoming light into 3 spectral ranges, and image with three monochrome image sensors. The use of a color-matched light source, off-center individual pinhole and monochrome image sensors allow the system to achieve better sensitivity and optical resolution. The use of coherent lasers light sources with high-speed cameras improves the velocity measurement dynamic range. The performance of the proposed multi-spectral system is first evaluated with a simulation model based on the finite element method (FEM). The performance is also compared numerically with the CC3DμPTV system. The test results show significant improvements on the signal to noise ratio and optical resolution. Originally presented in 11th International Symposium on Particle Image Velocimetry, Santa Barbara, California, September 14-16, 2015.

  4. Development of multi-spectral three-dimensional micro particle tracking velocimetry

    Science.gov (United States)

    Tien, Wei-Hsin

    2016-08-01

    The color-coded 3D micro particle tracking velocimetry system (CC3DμPTV) is a volumetric velocimetry technique that uses the defocusing digital particle image velocimetry (DDPIV) approach to reconstruct the 3D location of the particle. It is suited for microscopic flow visualization because of the single camera configuration. However, several factors limit the performance of the system. In this study, the limitation of the CC3DμPTV is discussed in detail and a new concept of a multi-camera 3D μ-PTV system is proposed to improve the performance of the original CC3DμPTV system. The system utilizes two dichroic beam splitters to separate the incoming light into 3 spectral ranges, and image with three monochrome image sensors. The use of a color-matched light source, off-center individual pinhole and monochrome image sensors allow the system to achieve better sensitivity and optical resolution. The use of coherent lasers light sources with high-speed cameras improves the velocity measurement dynamic range. The performance of the proposed multi-spectral system is first evaluated with a simulation model based on the finite element method (FEM). The performance is also compared numerically with the CC3DμPTV system. The test results show significant improvements on the signal to noise ratio and optical resolution. Originally presented in 11th International Symposium on Particle Image Velocimetry, Santa Barbara, California, September 14–16, 2015.

  5. Asynchronous Power Flow Controller

    Directory of Open Access Journals (Sweden)

    Rahul Juneja

    2014-04-01

    Full Text Available In the present system demand of electrical power increases so fast and transfer of electrical power is need of today‟s scenario. . The electrical power is transfer at same frequency through AC transmission line. However, power generation may be at different frequencies such as wind generation, sources at islanding or power generation in different countries. The proposed Asynchronous Power Flow Controller (APFC system essentially consists of two back-to-back voltage source converters as “Shunt Converter” and “Series Converter” which is coupled via a common dc link provided by a dc storage capacitor This paper suggests the power transfer and control between the sources operating at different or same frequencies.

  6. Visualisation of γH2AX foci caused by heavy ion particle traversal; distinction between core track versus non-track damage.

    Directory of Open Access Journals (Sweden)

    Nakako Izumi Nakajima

    Full Text Available Heavy particle irradiation produces complex DNA double strand breaks (DSBs which can arise from primary ionisation events within the particle trajectory. Additionally, secondary electrons, termed delta-electrons, which have a range of distributions can create low linear energy transfer (LET damage within but also distant from the track. DNA damage by delta-electrons distant from the track has not previously been carefully characterised. Using imaging with deconvolution, we show that at 8 hours after exposure to Fe (∼200 keV/µm ions, γH2AX foci forming at DSBs within the particle track are large and encompass multiple smaller and closely localised foci, which we designate as clustered γH2AX foci. These foci are repaired with slow kinetics by DNA non-homologous end-joining (NHEJ in G1 phase with the magnitude of complexity diminishing with time. These clustered foci (containing 10 or more individual foci represent a signature of DSBs caused by high LET heavy particle radiation. We also identified simple γH2AX foci distant from the track, which resemble those arising after X-ray exposure, which we attribute to low LET delta-electron induced DSBs. They are rapidly repaired by NHEJ. Clustered γH2AX foci induced by heavy particle radiation cause prolonged checkpoint arrest compared to simple γH2AX foci following X-irradiation. However, mitotic entry was observed when ∼10 clustered foci remain. Thus, cells can progress into mitosis with multiple clusters of DSBs following the traversal of a heavy particle.

  7. Pro asynchronous programming with .NET

    CERN Document Server

    Blewett, Richard; Ltd, Rock Solid Knowledge

    2014-01-01

    Pro Asynchronous Programming with .NET teaches the essential skill of asynchronous programming in .NET. It answers critical questions in .NET application development, such as: how do I keep my program responding at all times to keep my users happy how do I make the most of the available hardware how can I improve performanceIn the modern world, users expect more and more from their applications and devices, and multi-core hardware has the potential to provide it. But it takes carefully crafted code to turn that potential into responsive, scalable applications.With Pro Asynchronous Programming

  8. Principles and biophysical applications of single particle super-localization and rotational tracking

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Yan [Iowa State Univ., Ames, IA (United States)

    2013-01-01

    While conventional Single Particle Tracking (SPT) techniques acquire 2D or 3D trajectories of particle probes, we have developed Single Particle Orientation and Rotational Tracking (SPORT) techniques to extract orientation and rotational information. Combined with DIC microscopy, the SPORT technique has been applied in biophysical studies, including membrane diffusion and intracellular transport. The rotational dynamics of nanoparticle vectors on live cell membranes was recorded and its influence on the fate of these nanoparticle vectors was elucidated. The rotational motions of gold nanorods with various surface modifiers were tracked continuously at a temporal resolution of 5 ms under a DIC microscope. We found that the rotational behaviors of gold nanorod vectors are strongly related to their surface charge, specific surface functional groups, and the availability of receptors on cell membranes. The study of rotational Brownian motion of nanoparticles on cell membranes will lead to a better understanding of the mechanisms of drug delivery and provide guidance in designing surface modification strategies for drug delivery vectors under various circumstances. To characterize the rotation mode of surface functionalized gold nanorods on cell membranes, the SPORT technique is combined with the correlation analysis of the bright and dark DIC intensities. The unique capabilities of visualizing and understanding rotational motions of functionalized nanoparticles on live cell membranes allow us to correlate rotational and translational dynamics in unprecedented detail and provide new insights for complex membrane processes, including electrostatic interactions, ligand-receptor binding, and lateral (confined and hopping) diffusion of membrane receptors. Surface-functionalized nanoparticles interact with the membrane in fundamentally different ways and exhibit distinct rotational modes. The early events of particle-membrane approach and attachment are directly visualized

  9. A particle-tracking approach for accurate material derivative measurements with tomographic PIV

    Science.gov (United States)

    Novara, Matteo; Scarano, Fulvio

    2013-08-01

    The evaluation of the instantaneous 3D pressure field from tomographic PIV data relies on the accurate estimate of the fluid velocity material derivative, i.e., the velocity time rate of change following a given fluid element. To date, techniques that reconstruct the fluid parcel trajectory from a time sequence of 3D velocity fields obtained with Tomo-PIV have already been introduced. However, an accurate evaluation of the fluid element acceleration requires trajectory reconstruction over a relatively long observation time, which reduces random errors. On the other hand, simple integration and finite difference techniques suffer from increasing truncation errors when complex trajectories need to be reconstructed over a long time interval. In principle, particle-tracking velocimetry techniques (3D-PTV) enable the accurate reconstruction of single particle trajectories over a long observation time. Nevertheless, PTV can be reliably performed only at limited particle image number density due to errors caused by overlapping particles. The particle image density can be substantially increased by use of tomographic PIV. In the present study, a technique to combine the higher information density of tomographic PIV and the accurate trajectory reconstruction of PTV is proposed (Tomo-3D-PTV). The particle-tracking algorithm is applied to the tracers detected in the 3D domain obtained by tomographic reconstruction. The 3D particle information is highly sparse and intersection of trajectories is virtually impossible. As a result, ambiguities in the particle path identification over subsequent recordings are easily avoided. Polynomial fitting functions are introduced that describe the particle position in time with sequences based on several recordings, leading to the reduction in truncation errors for complex trajectories. Moreover, the polynomial regression approach provides a reduction in the random errors due to the particle position measurement. Finally, the acceleration

  10. Development of the Pattern Recognition Algorithm for Low Energy Particles in the Inner Tracking System of ALICE

    CERN Document Server

    Kolojvari, A A; CERN. Geneva; Tulina, T A

    1994-01-01

    The work is being carried out on the development of pattern recognition / initial parameters reconstruction algorithm for low energy charged particles tracks in the Inner Tracking System (ITS) of ALICE at the LHC. The algorithm should use the information only from ITS since it is supposed that it will be applied mainly to the particles which do not reach the next tracking detector, the TPC, due to their low energy and the presence of magnetic field. The algorithm is based on the transformation of any three space coordinate measurements inside the sensitive volume, placed into the solenoidal magnetic field, to the space of initial track parameters. The toy program for recognition of regular spiral trajectories is created. Some ideas are developed and tested. The further possibilities are discussed.

  11. Evaluation of Guiding Device for Downstream Fish Migration with in-Field Particle Tracking Velocimetry and CFD

    Directory of Open Access Journals (Sweden)

    Staffan Lundstrom

    2015-01-01

    Full Text Available The performance of a fish guiding device located just upstream a hydropower plant is scrutinized. The device is designed to redirect surface orientated down-stream migrating fish (smolts away from the turbines towards a spillway that act as a relatively safe fishway. Particles are added up-stream the device and the fraction particles going to the spillway is measured. A two-frame Particle Tracking Velocimetry algorithm is used to derive the velocity field of the water. The experimental results are compared to simulations with CFD. If the smolts move passively as the particles used in the study the guiding device works very well and some modifications may optimize its performance. In-field Particle Tracking Velocimetry is a suitable technique for the current case and the results compare well with numerical simulations.

  12. Registration of alpha particles in Makrofol-E nuclear track detectors

    Science.gov (United States)

    Rammah, Y. S.; Abdalla, Ayman M.; Ashraf, O.; Ashry, A. H.

    2016-06-01

    Fast detection of alpha particles in the range from 1 to 5 MeV in Makrofol-E polycarbonate nuclear track detectors (PCTDs) using a new chemical etchant was investigated. 252Cf and 241Am-thin open sources were used for irradiating Makrofol-E detectors with fission fragments and alpha particles in air at normal pressure and temperature (NPT). A chain of experimental work has been carried out using new etchants to register alpha particle in short time in Makrofol-E polycarbonate detectors. The etching efficiency were exhibited a clear dependence on the amount of methanol in the etching solution and etching time. The optimized chemical condition obtained at this stage of development for 200 μm Makrofol-E detectors are (8 ml of 10 N NaOH + 2 ml CH3OH) etching solutions at 60 °C for 3 h. In this study; it is possible to observe energy detection windows for Makrofol-E detectors according to applied etching duration. Makrofol-E introduced the characteristic Bragg peak, which indicates the advantages of this detector as alpha spectrometer. Consequently, the suggested new etchant can be developed for heavy ions detection and monitoring radon levels and its daughters.

  13. A Study Of Laser Induced Fluorescence In Neon As A Potential Particle Tracking Mechanism

    CERN Document Server

    Brookes, D J

    2000-01-01

    A new method to register the tracks of charged particles has been proposed employing laser induced fluorescence in the 1s5 - 2p9 cycling transition of neon gas as a method of determining the trajectory of a charged particle through that gas. A particle passing through neon gas will leave behind a trail of atoms trapped in the 1s5 metastable state. These metastable atoms can be made to fluoresce by pumping them to the 2p 9 state with a properly tuned laser. The 2p9 state only decays back to the 1s5 state, allowing the process to be repeated. The lifetime of the cycling transition is long enough to image when the neon atom is isolated, but collisions with other atoms can shorten this lifetime considerably. In this work the collisional deactivation rate has been measured from room temperature to the boiling point of neon. The collisional mixing rate ranged from 0.261×10- 11cm3s at 30K to 3.1×10- 11cm3s at 300K. The resulting lifetime was found to be 1130ns in 10torr of neon. The life of the neon cycling transi...

  14. Particle path tracking method in two- and three-dimensional continuously rotating detonation engines

    International Nuclear Information System (INIS)

    The particle path tracking method is proposed and used in two-dimensional (2D) and three-dimensional (3D) numerical simulations of continuously rotating detonation engines (CRDEs). This method is used to analyze the combustion and expansion processes of the fresh particles, and the thermodynamic cycle process of CRDE. In a 3D CRDE flow field, as the radius of the annulus increases, the no-injection area proportion increases, the non-detonation proportion decreases, and the detonation height decreases. The flow field parameters on the 3D mid annulus are different from in the 2D flow field under the same chamber size. The non-detonation proportion in the 3D flow field is less than in the 2D flow field. In the 2D and 3D CRDE, the paths of the flow particles have only a small fluctuation in the circumferential direction. The numerical thermodynamic cycle processes are qualitatively consistent with the three ideal cycle models, and they are right in between the ideal F—J cycle and ideal ZND cycle. The net mechanical work and thermal efficiency are slightly smaller in the 2D simulation than in the 3D simulation. In the 3D CRDE, as the radius of the annulus increases, the net mechanical work is almost constant, and the thermal efficiency increases. The numerical thermal efficiencies are larger than F—J cycle, and much smaller than ZND cycle. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  15. Automated 3D Particle Field Extraction and Tracking System Using Digital in-line Holography

    Directory of Open Access Journals (Sweden)

    Hesham Eldeeb

    2006-01-01

    Full Text Available Digital holography for 3D particle field extraction and tracking is an active research topic. It has a great application in realizing characterization of micro-scale structures in microelectromechanical systems (MEMS with high resolution and accuracy. In-line configuration is studied in this study as the fundamental structure of a digital holography system. Digital holographic approach, not only eliminates wet chemical processing and mechanical scanning, but also enables the use of complex amplitude information inaccessible by optical reconstruction, thereby allowing flexible reconstruction algorithms to achieve optimization of specific information. However, owing to the inherently low pixel resolution of solid-state imaging sensors, digital holography gives poor depth resolution for images. This problem severely impairs the usefulness of digital holography especially in densely populated particle fields. This study describes a system that significantly improves particle axial-location accuracy by exploring the reconstructed complex amplitude information, compared with other numerical reconstruction schemes that are merely traditional optical reconstruction. Theoretical analysis and experimental results demonstrate that in-line configuration presents advantageous in enhancing the system performance. Greater flexibility of the system, higher lateral resolution and lower speckle noise can be achieved

  16. GPU-based quasi-real-time Track Recognition in Imaging Devices: from raw Data to Particle Tracks

    CERN Document Server

    Bozza, Cristiano; De Sio, Chiara; Stellacci, Simona Maria

    2015-01-01

    Nuclear emulsions as tracking devices have been used by recent experiments thanks to fast automatic microscopes for emulsion readout. Automatic systems are evolving towards GPU-based solutions. Real-time imaging is needed to drive the motion of the microscope axes and 3D track recognition occurs quasi-online in local GPU clusters. The algorithms implemented in the Quick Scanning System are sketched. Most of them are very general and might turn out useful for other detector

  17. Increase in the area of etched alpha-particle tracks in CR-39 plastic with increasing storage time under nitrogen

    CERN Document Server

    Bhakta, J R; Miles, J C H

    1999-01-01

    The area of etched tracks in CR-39 (polyallyl diglycol carbonate, PADC) exposed to alpha-particles from an americium-241 source has been investigated as a function of post-exposure storage time in a dry nitrogen atmosphere. Data were collected over 2.5 years and the results show that the nominal maximum area of the track area distribution increases with increasing storage time.

  18. A Bayesian framework with an auxiliary particle filter for GMTI-based ground vehicle tracking aided by domain knowledge

    Science.gov (United States)

    Yu, Miao; Liu, Cunjia; Chen, Wen-hua; Chambers, Jonathon

    2014-06-01

    In this work, we propose a new ground moving target indicator (GMTI) radar based ground vehicle tracking method which exploits domain knowledge. Multiple state models are considered and a Monte-Carlo sampling based algorithm is preferred due to the manoeuvring of the ground vehicle and the non-linearity of the GMTI measurement model. Unlike the commonly used algorithms such as the interacting multiple model particle filter (IMMPF) and bootstrap multiple model particle filter (BS-MMPF), we propose a new algorithm integrating the more efficient auxiliary particle filter (APF) into a Bayesian framework. Moreover, since the movement of the ground vehicle is likely to be constrained by the road, this information is taken as the domain knowledge and applied together with the tracking algorithm for improving the tracking performance. Simulations are presented to show the advantages of both the new algorithm and incorporation of the road information by evaluating the root mean square error (RMSE).

  19. Energy-efficient collaborative target tracking algorithm using cost-reference particle filtering in wireless acoustic sensor networks

    Institute of Scientific and Technical Information of China (English)

    YU Zhi-jun; WEI Jian-ming; LIU Hai-tao

    2009-01-01

    Target tracking is one of the most important applications of wireless sensor networks. Optimized computation and energy dissipation are critical requirements to save the limited resource of sensor nodes. A new robust and energy-efficient collaborative target tracking framework is proposed in this article. After a target is detected, only one active cluster is responsible for the tracking task at each time step. The tracking algorithm is distributed by passing the sensing and computation operations from one cluster to another. An event-driven cluster reforming scheme is also proposed for balancing energy consumption among nodes. Observations from three cluster members are chosen and a new class of particle filter termed cost-reference particle filter (CRPF) is introduced to estimate the target motion at the cluster head. This CRPF method is quite robust for wireless sensor network tracking applications because it drops the strong assumptions of knowing the probability distributions of the system process and observation noises. In simulation experiments, the performance of the proposed collaborative target tracking algorithm is evaluated by the metrics of tracking precision and network energy consumption.

  20. Plasma electron hole kinematics. II. Hole tracking Particle-In-Cell simulation

    Science.gov (United States)

    Zhou, C.; Hutchinson, I. H.

    2016-08-01

    The kinematics of a 1-D electron hole is studied using a novel Particle-In-Cell simulation code. A hole tracking technique enables us to follow the trajectory of a fast-moving solitary hole and study quantitatively hole acceleration and coupling to ions. We observe a transient at the initial stage of hole formation when the hole accelerates to several times the cold-ion sound speed. Artificially imposing slow ion speed changes on a fully formed hole causes its velocity to change even when the ion stream speed in the hole frame greatly exceeds the ion thermal speed, so there are no reflected ions. The behavior that we observe in numerical simulations agrees very well with our analytic theory of hole momentum conservation and the effects of "jetting."

  1. Advanced cell therapies: targeting, tracking and actuation of cells with magnetic particles.

    Science.gov (United States)

    Connell, John J; Patrick, P Stephen; Yu, Yichao; Lythgoe, Mark F; Kalber, Tammy L

    2015-01-01

    Regenerative medicine would greatly benefit from a new platform technology that enabled measurable, controllable and targeting of stem cells to a site of disease or injury in the body. Superparamagnetic iron-oxide nanoparticles offer attractive possibilities in biomedicine and can be incorporated into cells, affording a safe and reliable means of tagging. This review describes three current and emerging methods to enhance regenerative medicine using magnetic particles to guide therapeutic cells to a target organ; track the cells using MRI and assess their spatial localization with high precision and influence the behavior of the cell using magnetic actuation. This approach is complementary to the systemic injection of cell therapies, thus expanding the horizon of stem cell therapeutics.

  2. Imaging of molecular surface dynamics in brain slices using single-particle tracking.

    Science.gov (United States)

    Biermann, B; Sokoll, S; Klueva, J; Missler, M; Wiegert, J S; Sibarita, J-B; Heine, M

    2014-01-01

    Organization of signalling molecules in biological membranes is crucial for cellular communication. Many receptors, ion channels and cell adhesion molecules are associated with proteins important for their trafficking, surface localization or function. These complexes are embedded in a lipid environment of varying composition. Binding affinities and stoichiometry of such complexes were so far experimentally accessible only in isolated systems or monolayers of cell culture. Visualization of molecular dynamics within signalling complexes and their correlation to specialized membrane compartments demand high temporal and spatial resolution and has been difficult to demonstrate in complex tissue like brain slices. Here we demonstrate the feasibility of single-particle tracking (SPT) in organotypic brain slices to measure molecular dynamics of lipids and transmembrane proteins in correlation to synaptic membrane compartments. This method will provide important information about the dynamics and organization of surface molecules in the complex environment of neuronal networks within brain slices. PMID:24429796

  3. Application of Gauss's law space-charge limited emission model in iterative particle tracking method

    Science.gov (United States)

    Altsybeyev, V. V.; Ponomarev, V. A.

    2016-11-01

    The particle tracking method with a so-called gun iteration for modeling the space charge is discussed in the following paper. We suggest to apply the emission model based on the Gauss's law for the calculation of the space charge limited current density distribution using considered method. Based on the presented emission model we have developed a numerical algorithm for this calculations. This approach allows us to perform accurate and low time consumpting numerical simulations for different vacuum sources with the curved emitting surfaces and also in the presence of additional physical effects such as bipolar flows and backscattered electrons. The results of the simulations of the cylindrical diode and diode with elliptical emitter with the use of axysimmetric coordinates are presented. The high efficiency and accuracy of the suggested approach are confirmed by the obtained results and comparisons with the analytical solutions.

  4. Are particle-tracking algorithms the adequate method to determine migration paths for performance assessment

    International Nuclear Information System (INIS)

    Nuclear waste repositories have to be constructed in such a way that no hazardous effects on the environment do occur even after closure of the facility. To show compliance with this requirement longterm safety assessments simulate potential releases of radionuclides from the repository, their migration through the geosphere and their potential hazards in the biosphere. An integral part of these simulations is the calculation of groundwater flow and nuclide transport in the rocks surrounding the repository. Since transport calculations require great computational efforts these should be restricted to the regions of interest. These are usually derived from the groundwater flow models by means of particle-tracking algorithms. However, these do not necessarily represent the fastest travel path to the environment. Therefore one has to be aware of the limitations of pathlines for use in longterm safety assessments. Computer codes used: NAMMU. 6 figs., 3 refs

  5. Stochastic particle barcoding for single-cell tracking and multiparametric analysis.

    Science.gov (United States)

    Castellarnau, M; Szeto, G L; Su, H-W; Tokatlian, T; Love, J C; Irvine, D J; Voldman, J

    2015-01-27

    This study presents stochastic particle barcoding (SPB), a method for tracking cell identity across bioanalytical platforms. In this approach, single cells or small collections of cells are co-encapsulated within an enzymatically-degradable hydrogel block along with a random collection of fluorescent beads, whose number, color, and position encode the identity of the cell, enabling samples to be transferred in bulk between single-cell assay platforms without losing the identity of individual cells. The application of SPB is demonstrated for transferring cells from a subnanoliter protein secretion/phenotyping array platform into a microtiter plate, with re-identification accuracies in the plate assay of 96±2%. Encapsulated cells are recovered by digesting the hydrogel, allowing subsequent genotyping and phenotyping of cell lysates. Finally, a model scaling is developed to illustrate how different parameters affect the accuracy of SPB and to motivate scaling of the method to thousands of unique blocks.

  6. User guide for MODPATH Version 7—A particle-tracking model for MODFLOW

    Science.gov (United States)

    Pollock, David W.

    2016-09-26

    MODPATH is a particle-tracking post-processing program designed to work with MODFLOW, the U.S. Geological Survey (USGS) finite-difference groundwater flow model. MODPATH version 7 is the fourth major release since its original publication. Previous versions were documented in USGS Open-File Reports 89–381 and 94–464 and in USGS Techniques and Methods 6–A41.MODPATH version 7 works with MODFLOW-2005 and MODFLOW–USG. Support for unstructured grids in MODFLOW–USG is limited to smoothed, rectangular-based quadtree and quadpatch grids.A software distribution package containing the computer program and supporting documentation, such as input instructions, output file descriptions, and example problems, is available from the USGS over the Internet (http://water.usgs.gov/ogw/modpath/).

  7. SPACE CHARGE SIMULATION METHODS INCORPORATED IN SOME MULTI - PARTICLE TRACKING CODES AND THEIR RESULTS COMPARISON.

    Energy Technology Data Exchange (ETDEWEB)

    BEEBE - WANG,J.; LUCCIO,A.U.; D IMPERIO,N.; MACHIDA,S.

    2002-06-03

    Space charge in high intensity beams is an important issue in accelerator physics. Due to the complicity of the problems, the most effective way of investigating its effect is by computer simulations. In the resent years, many space charge simulation methods have been developed and incorporated in various 2D or 3D multi-particle-tracking codes. It has becoming necessary to benchmark these methods against each other, and against experimental results. As a part of global effort, we present our initial comparison of the space charge methods incorporated in simulation codes ORBIT++, ORBIT and SIMPSONS. In this paper, the methods included in these codes are overviewed. The simulation results are presented and compared. Finally, from this study, the advantages and disadvantages of each method are discussed.

  8. Irreproducibility of Diffusion Coefficients in Single-Particle-Tracking Measurements in Heterogeneous Environment

    CERN Document Server

    Akimoto, Takuma

    2016-01-01

    Local diffusion coefficients in living cells are highly heterogeneous and may change over time. Such a time-dependent and spatially heterogeneous environment results in irreproducibility of single-particle-tracking measurements. Here, we provide rigorous descriptions of equilibrium and non-equilibrium diffusion processes for a heterogeneous diffusion model in living cells. We give exact solutions for the mean square displacement (MSD) and the relative standard deviation of the time-averaged MSD for equilibrium and non-equilibrium situations. We find that the time-averaged MSD grows linearly with time and that the diffusion coefficients are intrinsically random in non-equilibrium situations. Our findings pave the way for a theoretical understanding of irreproducible diffusion coefficients in cell biology.

  9. High-LET dose-response characteristics by track structure theory of heavy charged particles

    International Nuclear Information System (INIS)

    The track structure theory developed by Katz and co-workers ascribes the effect of high-LET radiation to the highly inhomogeneous dose distribution due to low energy Δ-rays ejected from the particle track. The theory predicts the effectiveness of high-LET radiation by using the ion parameters zsub(eff') effective charge of the ion, and β = v/c, the relative ion velocity, together with the characteristic dose D37 derived from low-LET dose-response characteristic of the detector and the approximate size asub(0) of the sensitive element of the detector. 60Co gamma-irradiation is used as a reference low-LET radiation, while high-LET radiation ranging from 16 MeV protons to 4 MeV/amu 160-ions covering an initial LET range of 30-5500 MeVcm2/g is obtained from a tandem Van de Graaff accelerator. A thin film (5mg/cm2) radiochromic dye cyanide plastic dosemeter was used as detector with the characteristic dose of 16.8 Mrad and a sensitive element size of 10-7 cm. Theoretical and experimental effectiveness, RBE, agreed within 10 to 25% depending on LET. (author)

  10. Combined application of alpha-track and fission-track techniques for detection of plutonium particles in environmental samples prior to isotopic measurement using thermo-ionization mass spectrometry.

    Science.gov (United States)

    Lee, Chi-Gyu; Suzuki, Daisuke; Esaka, Fumitaka; Magara, Masaaki; Kimura, Takaumi

    2011-07-15

    The fission track technique is a sensitive detection method for particles which contain radio-nuclides like (235)U or (239)Pu. However, when the sample is a mixture of plutonium and uranium, discrimination between uranium particles and plutonium particles is difficult using this technique. In this study, we developed a method for detecting plutonium particles in a sample mixture of plutonium and uranium particles using alpha track and fission track techniques. The specific radioactivity (Bq/g) for alpha decay of plutonium is several orders of magnitude higher than that of uranium, indicating that the formation of the alpha track due to alpha decay of uranium can be disregarded under suitable conditions. While alpha tracks in addition to fission tracks were detected in a plutonium particle, only fission tracks were detected in a uranium particle, thereby making the alpha tracks an indicator for detecting particles containing plutonium. In addition, it was confirmed that there is a linear relationship between the numbers of alpha tracks produced by plutonium particles made of plutonium certified standard material and the ion intensities of the various plutonium isotopes measured by thermo-ionization mass spectrometry. Using this correlation, the accuracy in isotope ratios, signal intensity and measurement errors is presumable from the number of alpha tracks prior to the isotope ratio measurements by thermal ionization mass spectrometry. It is expected that this method will become an effective tool for plutonium particle analysis. The particles used in this study had sizes between 0.3 and 2.0 μm.

  11. Improvements on Particle Tracking Velocimetry: model-free calibration and noiseless measurement of second order statistics of the velocity field

    CERN Document Server

    Machicoane, Nathanael; Bourgoin, Mickael; Aliseda, Alberto; Volk, Romain

    2016-01-01

    This article describes two independent developments aimed at improving the Particle Tracking Method for measurements of flow or particle velocities. First, a stereoscopic multicamera calibration method that does not require any optical model is described and evaluated. We show that this new calibration method gives better results than the most commonly-used technique, based on the Tsai camera/optics model. Additionally, the methods uses a simple interpolant to compute the transformation matrix and it is trivial to apply for any experimental fluid dynamics visualization set up. The second contribution proposes a solution to remove noise from Eulerian measurements of velocity statistics obtained from Particle Tracking velocimetry, without the need of filtering and/or windowing. The novel method presented here is based on recomputing particle displacement measurements from two consecutive frames for multiple different time-step values between frames. We show the successful application of this new technique to re...

  12. Particle tracking via RFID technology to monitor bedload sediment dynamics in mountain streams

    Science.gov (United States)

    Toro, Matteo; Fraccarollo, Luigi; Corbo, Simona; Maggioni, Alberto; Brardinoni, Francesco

    2015-04-01

    In this contribution we present preliminary results on the monitoring of bedload entrainment and transport in two mountain streams, the Grigno Creek (90 km2) and its tributary, the Tolvà Creek (14 km2), located in Valsugana, Autonomous Province of Trento. In particular, we monitor bedload by means of Radio Frequency Identification (RFID) technology in conjunction with Passive Integrated Transponders (PIT) (e.g., Lamarre et al., 2005) injected into pebble-to-cobble sized tracer stones (b-axis ranging from 30 to 130 mm). In the Grigno Creek 120 PITs were released in December 2013 along a 100-m channel reach and have been surveyed 10 times. In the Tolvà Creek 100 PITs were released in July 2013 along a 100-m channel reach, and the site has been surveyed 4 times. Particle tracking is conducted by integrating two complementary antenna types: (i) a portable one, which enables to estimate travel distances of tagged clasts; and (ii) a set of four fixed antennas (25m apart from each other), which allows detecting motion/rest periods of particles, entrainment thresholds and transport velocities. Particle tracking is combined with on-site high-frequency (i.e., 10 minutes) water stage monitoring. Salt dilution method is monthly applied to relate flow discharge to water stage. The analyzed river reaches extend over different morphologic units (steps, pools, glides and boulder-cascades). We are looking to estimate (i) the channel forming discharge; (ii) a quantitative evaluation of specific bedload transport. These information will be associated to the surficial bed texture and bed morphology. Data collected from fixed and mobile antennas will enable to infer statistical information of the trajectories run by tracer ensemble, in particular the step lengths, the total travel distances and the rest periods. Lamarre H., MacVicar B., Roy A.G. 2005 Using Passive Integrated Transponder (PIT) tags to investigate sediment transport in gravel-bed rivers. Journal of Sedimentary Research

  13. Quantifying the dynamic transition of hydrogenated castor oil gels measured via multiple particle tracking microrheology.

    Science.gov (United States)

    Wehrman, Matthew D; Lindberg, Seth; Schultz, Kelly M

    2016-08-14

    Rheological modifiers are essential ingredients in commercial materials that exploit facile and repeatable phase transitions. Although rheological modifiers are used to change flow behavior or quiescent stability, the complex properties of particulate gels during dilution is not well studied. We characterize a dynamically evolving colloidal gel, hydrogenated castor oil (HCO), a naturally sourced material, used in consumer products. This HCO scaffold consists of fibrous colloids, a surfactant (linear alkylbenzene sulfonate) and water. The gel undergoes critical transitions, degradation and formation, in response to an osmotic pressure gradient. Multiple particle tracking microrheology (MPT) measures the evolving material properties. In MPT, fluorescent probe particles are embedded into the sample and Brownian motion is measured. MPT data are analyzed using time-cure superposition, identifying critical transition times and critical relaxation exponents for degradation and formation where tc,deg = 102.5 min, ndeg = 0.77 ± 0.09, tc,for = 31.9 min, and nfor = 0.94 ± 0.11, respectively. During degradation and formation HCO gels evolve heterogeneously, this heterogeneity is characterized spatially and temporally. Heterogeneity of the gel is quantified by comparing variances of single particle van Hove correlation functions using an F-test with a 95% confidence interval. HCO transitions have rheological heterogeneous microenvironments that are homogeneously distributed throughout the field of view. Although HCO gels do evolve heterogeneously, this work determines that these heterogeneities do not significantly change traditional MPT measurements but the analysis techniques developed provide additional information on the unique heterogeneous scaffold microenvironments. This creates a toolbox that can be widely applied to other scaffolds during dynamic transitions. PMID:27396611

  14. A flame particle tracking analysis of turbulence–chemistry interaction in hydrogen–air premixed flames

    KAUST Repository

    Uranakara, Harshavardhana A.

    2015-11-21

    Interactions of turbulence, molecular transport, and energy transport, coupled with chemistry play a crucial role in the evolution of flame surface geometry, propagation, annihilation, and local extinction/re-ignition characteristics of intensely turbulent premixed flames. This study seeks to understand how these interactions affect flame surface annihilation of lean hydrogen–air premixed turbulent flames. Direct numerical simulations (DNSs) are conducted at different parametric conditions with a detailed reaction mechanism and transport properties for hydrogen–air flames. Flame particle tracking (FPT) technique is used to follow specific flame surface segments. An analytical expression for the local displacement flame speed (Sd) of a temperature isosurface is considered, and the contributions of transport, chemistry, and kinematics on the displacement flame speed at different turbulence-flame interaction conditions are identified. In general, the displacement flame speed for the flame particles is found to increase with time for all conditions considered. This is because, eventually all flame surfaces and their resident flame particles approach annihilation by reactant island formation at the end of stretching and folding processes induced by turbulence. Statistics of principal curvature evolving in time, obtained using FPT, suggest that these islands are ellipsoidal on average enclosing fresh reactants. Further examinations show that the increase in Sd is caused by the increased negative curvature of the flame surface and eventual homogenization of temperature gradients as these reactant islands shrink due to flame propagation and turbulent mixing. Finally, the evolution of the normalized, averaged, displacement flame speed vs. stretch Karlovitz number are found to collapse on a narrow band, suggesting that a unified description of flame speed dependence on stretch rate may be possible in the Lagrangian description.

  15. ASYNCHRONOUS ELECTRONIC DISCUSSION GROUP:

    Directory of Open Access Journals (Sweden)

    Tina Lim Swee KIM

    2007-01-01

    Full Text Available This paper examines the practice of online discussion in a course specially tailored for in-service teachers who are pursuing their basic degree qualification at a teacher training institute. Analyses of postings to the asynchronous electronic discussion group were made according to the type of postings as proposed by Poole (2000. Four focus areas were looked into, that is, content, technical, procedural, or non-academic. Analyses were done for each quarter of the 12 weeks of interaction. At the end of the learners’ participation in the EDG and before their end-of-course examination, the participants were then given a paper-based questionnaire asking their perceptions on the use of EDG as part of their coursework on the whole. Six aspects of EDG were examined, these are;Ø technical aspects, Ø motivation to use the EDG, Ø quality of interaction, Ø tutor’s response, Ø perceived learning, and Ø attitude towards EDG. Analyses on postings for the EDG showed that the bulk of the postings were made in the last quarter of the online discussions. Further, 97.8% of the postings were on content and the types of content posting registered were predominantly questions (41.19% and those that sought clarification/elaboration (37.48%. Findings from this study suggest that overall the participants were satisfied with the six aspects of EDG examined. The aspect that recorded the highest mean was ‘motivation to read tutor’s responses’ whilst the lowest mean (and the only one with negative perception was for ‘worthiness of time spent on online discussions’.

  16. Target Tracking Approximation Algorithms with Particle Filter Optimization and Fault-Tolerant Analysis in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Xiang Gao

    2012-05-01

    Full Text Available In order to process target tracking approximation with unknown motion state models beforehand in a two-dimensional field of binary proximity sensors, the algorithms based on cost functions of particle filters and near-linear curve simple optimization are proposed in this paper. Through moving target across detecting intersecting fields of sensor nodes sequentially, cost functions are introduced to solve target tracking approximation and velocity estimation which is not similar to traditional particle filters that rely on probabilistic assumptions about the motion states. Then a near-linear curve geometric approach is used to simplify and easily describe target trajectories that are below a certain error measure. Because there maybe some sensor nodes invalid in practice, so a fault-tolerant detection is applied to avoid the nodes’ reporting fault and also improve accuracy of tracking at the same time. The validity of our algorithms is demonstrated through simulation results.

  17. Spatio-temporal auxiliary particle filtering with l1-norm-based appearance model learning for robust visual tracking.

    Science.gov (United States)

    Kim, Du Yong; Jeon, Moongu

    2013-02-01

    In this paper, we propose an efficient and accurate visual tracker equipped with a new particle filtering algorithm and robust subspace learning-based appearance model. The proposed visual tracker avoids drifting problems caused by abrupt motion changes and severe appearance variations that are well-known difficulties in visual tracking. The proposed algorithm is based on a type of auxiliary particle filtering that uses a spatio-temporal sliding window. Compared to conventional particle filtering algorithms, spatio-temporal auxiliary particle filtering is computationally efficient and successfully implemented in visual tracking. In addition, a real-time robust principal component pursuit (RRPCP) equipped with l(1)-norm optimization has been utilized to obtain a new appearance model learning block for reliable visual tracking especially for occlusions in object appearance. The overall tracking framework based on the dual ideas is robust against occlusions and out-of-plane motions because of the proposed spatio-temporal filtering and recursive form of RRPCP. The designed tracker has been evaluated using challenging video sequences, and the results confirm the advantage of using this tracker.

  18. Lagrangian 3D particle tracking in high-speed flows: Shake-The-Box for multi-pulse systems

    Science.gov (United States)

    Novara, Matteo; Schanz, Daniel; Reuther, Nico; Kähler, Christian J.; Schröder, Andreas

    2016-08-01

    The Shake-The-Box (STB) particle tracking technique, recently introduced for time-resolved 3D particle image velocimetry (PIV) images, is applied here to data from a multi-pulse investigation of a turbulent boundary layer flow with adverse pressure gradient in air at 36 m/s ( Re τ = 10,650). The multi-pulse acquisition strategy allows for the recording of four-pulse long time-resolved sequences with a time separation of a few microseconds. The experimental setup consists of a dual-imaging system and a dual-double-cavity laser emitting orthogonal polarization directions to separate the four pulses. The STB particle triangulation and tracking strategy is adapted here to cope with the limited amount of realizations available along the time sequence and to take advantage of the ghost track reduction offered by the use of two independent imaging systems. Furthermore, a correction scheme to compensate for camera vibrations is discussed, together with a method to accurately identify the position of the wall within the measurement domain. Results show that approximately 80,000 tracks can be instantaneously reconstructed within the measurement volume, enabling the evaluation of both dense velocity fields, suitable for spatial gradients evaluation, and highly spatially resolved boundary layer profiles. Turbulent boundary layer profiles obtained from ensemble averaging of the STB tracks are compared to results from 2D-PIV and long-range micro particle tracking velocimetry; the comparison shows the capability of the STB approach in delivering accurate results across a wide range of scales.

  19. A shallow water equation solver and particle tracking method to evaluate the debris transport

    International Nuclear Information System (INIS)

    Debris generated by loss-of-coolant accident (LOCA) may run all over the containment floor, block the sump screen (or strainer), increase the hydraulic head loss across the screen, and eventually, have an adverse effect to long term recirculation cooling operation in pressurized water reactor (PWR). To resolve the problem from the issue, the replacement of containment recirculation sump strainer is being performed for the most of operating nuclear power plants (NPP) having limited strainer areas. The screen area required to incorporate the potential debris loading has been determined using the transport fraction (TF) defined by a ratio of amount of debris accumulated on screen to one generated by LOCA. For the most conventional NPP, the debris transport to the sump screen is initiated by the recirculation actuation. Therefore, evaluation of TF was based on the separated analyses on how the debris generated by LOCA is distributed to the containment floor before recirculation and on how much debris is transported by the flow in the containment pool after recirculation, respectively. This led to an approach to obtain TF values for blowdown phase, wash-down phase, pool recirculation phase, separately. Especially, the TF during recirculation phase has been calculated by steady state CFD analysis based that the break flow and recirculation safety injection flow are balanced, thus steady state flow field over the containment is established. However, such a phase separation cannot be applied to some NPP like the Advanced Power Reactor 1400 (APR1400) having no recirculation operation. Transport of debris to sump in the APR1400 is initiated from the early phase of a LOCA in fully transient manner. The present study is to calculate debris transport on the containment floor to sump in APR1400. For this purpose, a hydraulic model to calculate the transient flow field and a particle tracking model to trace the debris particle within the calculation domain are discussed

  20. Study of contrail microphysics in the vortex phase with a Lagrangian particle tracking model

    Directory of Open Access Journals (Sweden)

    S. Unterstrasser

    2010-06-01

    Full Text Available Crystal sublimation/loss is a~dominant feature of the contrail evolution during the vortex phase and has a substantial impact on the later contrail-to-cirrus transition. Previous studies showed that the fraction of crystals surviving the vortex phase depends primarily on relative humidity, temperature and the aircraft type. An existing model for contrail vortex phase simulations (with a 2–moment bulk microphysics scheme was upgraded with a newly developed state-of-the-art microphysics module (LCM which uses Lagrangian particle tracking. This allows for explicit process-oriented modelling of the ice crystal size distribution in contrast to the bulk approach. We show that it is of great importance to employ an advanced microphysics scheme to determine the crystal loss during the vortex phase. The LCM-model shows even larger sensitivities to the above mentioned key parameters than previously estimated with the bulk model. The impact of the initial crystal number is studied and for the first time also the initial width of the crystal size distribution. Both are shown to be relevant. This corroborates the need for a realistic representation of microphysical processes and knowledge of the ice phase characteristics.

  1. Study of contrail microphysics in the vortex phase with a Lagrangian particle tracking model

    Directory of Open Access Journals (Sweden)

    S. Unterstrasser

    2010-10-01

    Full Text Available Crystal sublimation/loss is a dominant feature of the contrail evolution during the vortex phase and has a substantial impact on the later contrail-to-cirrus transition. Previous studies showed that the fraction of crystals surviving the vortex phase depends primarily on relative humidity, temperature and the aircraft type. An existing model for contrail vortex phase simulations (with a 2-moment bulk microphysics scheme was upgraded with a newly developed state-of-the-art microphysics module (LCM which uses Lagrangian particle tracking. This allows for explicit process-oriented modelling of the ice crystal size distribution in contrast to the bulk approach. We show that it is of great importance to employ an advanced microphysics scheme to determine the crystal loss during the vortex phase. The LCM-model shows even larger sensitivities to the above mentioned key parameters than previously estimated with the bulk model. The impact of the initial crystal number is studied and for the first time also the initial width of the crystal size distribution. Both are shown to be relevant. This corroborates the need for a realistic representation of microphysical processes and knowledge of the ice phase characteristics.

  2. Uncovering homo-and hetero-interactions on the cell membrane using single particle tracking approaches

    Science.gov (United States)

    Torreno-Pina, Juan A.; Manzo, Carlo; Garcia-Parajo, Maria F.

    2016-03-01

    The plasma membrane of eukaryotic cells is responsible for a myriad of functions that regulate cell physiology and plays a crucial role in a multitude of processes that include adhesion, migration, signaling recognition and cell-cell communication. This is accomplished by specific interactions between different membrane components such as lipids and proteins on the lipid bilayer but also through interactions with the underlying cortical actin cytoskeleton on the intracellular side and the glycocalyx matrix in close proximity to the extracellular side. Advanced biophysical techniques, including single particle tracking (SPT) have revealed that the lateral diffusion of molecular components on the plasma membrane represents a landmark manifestation of such interactions. Indeed, by studying changes in the diffusivity of individual membrane molecules, including sub-diffusion, confined diffusion and/or transient arrest of molecules in membrane compartments, it has been possible to gain insight on the nature of molecular interactions and to infer on its functional role for cell response. In this review, we will revise some exciting results where SPT has been crucial to reveal homo- and hetero-interactions on the cell membrane.

  3. A review of progress in single particle tracking: from methods to biophysical insights

    Science.gov (United States)

    Manzo, Carlo; Garcia-Parajo, Maria F.

    2015-12-01

    Optical microscopy has for centuries been a key tool to study living cells with minimum invasiveness. The advent of single molecule techniques over the past two decades has revolutionized the field of cell biology by providing a more quantitative picture of the complex and highly dynamic organization of living systems. Amongst these techniques, single particle tracking (SPT) has emerged as a powerful approach to study a variety of dynamic processes in life sciences. SPT provides access to single molecule behavior in the natural context of living cells, thereby allowing a complete statistical characterization of the system under study. In this review we describe the foundations of SPT together with novel optical implementations that nowadays allow the investigation of single molecule dynamic events with increasingly high spatiotemporal resolution using molecular densities closer to physiological expression levels. We outline some of the algorithms for the faithful reconstruction of SPT trajectories as well as data analysis, and highlight biological examples where the technique has provided novel insights into the role of diffusion regulating cellular function. The last part of the review concentrates on different theoretical models that describe anomalous transport behavior and ergodicity breaking observed from SPT studies in living cells.

  4. Measuring the viscous and elastic properties of single cells using video particle tracking microrheology

    CERN Document Server

    Warren, Rebecca Louisa; Li, Xiang; Glidle, Andrew; Carlsson, Allan; Cooper, Jonathan M

    2011-01-01

    We present a simple and \\emph{non-invasive} experimental procedure to measure the linear viscoelastic properties of cells by passive video particle tracking microrheology. In order to do this, a generalised Langevin equation is adopted to relate the time-dependent thermal fluctuations of a bead, chemically bound to the cell's \\emph{exterior}, to the frequency-dependent viscoelastic moduli of the cell. It is shown that these moduli are related to the cell's cytoskeletal structure, which in this work is changed by varying the solution osmolarity from iso- to hypo-osmotic conditions. At high frequencies, the viscoelastic moduli frequency dependence changes from $\\propto \\omega^{3/4}$ found in iso-osmotic solutions to $\\propto \\omega^{1/2}$ in hypo--osmotic solutions; the first situation is typical of bending modes in isotropic \\textit{in vitro} reconstituted F--actin networks, and the second could indicate that the restructured cytoskeleton behaves as a gel with "\\textit{dangling branches}". The insights gained ...

  5. In Situ Mapping of the Mechanical Properties of Biofilms by Particle-tracking Microrheology.

    Science.gov (United States)

    Chew, Su C; Rice, Scott A; Kjelleberg, Staffan; Yang, Liang

    2015-01-01

    Bacterial cells are able to form surface-attached biofilm communities known as biofilms by encasing themselves in extracellular polymeric substances (EPS). The EPS serves as a physical and protective scaffold that houses the bacterial cells and consists of a variety of materials that includes proteins, exopolysaccharides and DNA. The composition of the EPS may change, which remodels the mechanic properties of the biofilm to further develop or support alternative biofilm structures, such as streamers, as a response to environmental cues. Despite this, there are little quantitative descriptions on how EPS components contribute to the mechanical properties and function of biofilms. Rheology, the study of the flow of matter, is of particular relevance to biofilms as many biofilms grow in flow conditions and are constantly exposed to shear stress. It also provides measurement and insight on the spreading of the biofilm on a surface. Here, particle-tracking microrheology is used to examine the viscoelasticity and effective crosslinking roles of different matrix components in various parts of the biofilm during development. This approach allows researchers to measure mechanic properties of biofilms at the micro-scale, which might provide useful information for controlling and engineering biofilms. PMID:26709625

  6. A review of progress in single particle tracking: from methods to biophysical insights.

    Science.gov (United States)

    Manzo, Carlo; Garcia-Parajo, Maria F

    2015-12-01

    Optical microscopy has for centuries been a key tool to study living cells with minimum invasiveness. The advent of single molecule techniques over the past two decades has revolutionized the field of cell biology by providing a more quantitative picture of the complex and highly dynamic organization of living systems. Amongst these techniques, single particle tracking (SPT) has emerged as a powerful approach to study a variety of dynamic processes in life sciences. SPT provides access to single molecule behavior in the natural context of living cells, thereby allowing a complete statistical characterization of the system under study. In this review we describe the foundations of SPT together with novel optical implementations that nowadays allow the investigation of single molecule dynamic events with increasingly high spatiotemporal resolution using molecular densities closer to physiological expression levels. We outline some of the algorithms for the faithful reconstruction of SPT trajectories as well as data analysis, and highlight biological examples where the technique has provided novel insights into the role of diffusion regulating cellular function. The last part of the review concentrates on different theoretical models that describe anomalous transport behavior and ergodicity breaking observed from SPT studies in living cells.

  7. Particle tracking velocimetry applied to estimate the pressure field around a Savonius turbine

    Science.gov (United States)

    Murai, Yuichi; Nakada, Taishi; Suzuki, Takao; Yamamoto, Fujio

    2007-08-01

    Particle tracking velocimetry (PTV) is applied to flows around a Savonius turbine. The velocity vector field measured with PTV is utilized to estimate the pressure field around the turbine, as well as to evaluate the torque performance. The main objective of the work is the establishment of the pressure estimation scheme required to discuss the turbine performance. First, the PTV data are interpolated on a regular grid with a fourth-order ellipsoidal differential equation to generate velocity vectors satisfying the third-order spatio-temporal continuity both in time and space. Second, the phase-averaged velocity vector information with respect to the turbine angle is substituted into three different types of pressure-estimating equations, i.e. the Poisson equation, the Navier-Stokes equation and the sub-grid scale model of turbulence. The results obtained based on the Navier-Stokes equation are compared with those based on the Poisson equation, and have shown several merits in employing the Navier-Stokes-based method for the PTV measurement. The method is applied to a rotating turbine with the tip-speed ratio of 0.5 to find the relationship between torque behaviour and flow structure in a phase-averaged sense. We have found that a flow attached to the convex surface of the blades induces low-pressure regions to drive the turbine, namely, the lift force helps the turbine blades to rotate even when the drag force is insufficient. Secondary mechanisms of torque generation are also discussed.

  8. Single-particle tracking of quantum dot-conjugated prion proteins inside yeast cells

    International Nuclear Information System (INIS)

    Research highlights: → We develop a method to track a quantum dot-conjugated protein in yeast cells. → We incorporate the conjugated quantum dot proteins into yeast spheroplasts. → We track the motions by conventional or 3D tracking microscopy. -- Abstract: Yeast is a model eukaryote with a variety of biological resources. Here we developed a method to track a quantum dot (QD)-conjugated protein in the budding yeast Saccharomyces cerevisiae. We chemically conjugated QDs with the yeast prion Sup35, incorporated them into yeast spheroplasts, and tracked the motions by conventional two-dimensional or three-dimensional tracking microscopy. The method paves the way toward the individual tracking of proteins of interest inside living yeast cells.

  9. Single-particle tracking of quantum dot-conjugated prion proteins inside yeast cells

    Energy Technology Data Exchange (ETDEWEB)

    Tsuji, Toshikazu; Kawai-Noma, Shigeko [Department of Biomolecular Engineering, Graduate School of Biosciences and Biotechnology, Tokyo Institute of Technology, B56, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501 (Japan); Pack, Chan-Gi [Cellular Informatics Laboratory, RIKEN Advanced Science Institute, Wako-shi, Saitama 351-0198 (Japan); Terajima, Hideki [Department of Biomolecular Engineering, Graduate School of Biosciences and Biotechnology, Tokyo Institute of Technology, B56, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501 (Japan); Yajima, Junichiro; Nishizaka, Takayuki [Department of Physics, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588 (Japan); Kinjo, Masataka [Laboratory of Molecular Cell Dynamics, Graduate School of Life Sciences, Hokkaido University, Sapporo 001-0021 (Japan); Taguchi, Hideki, E-mail: taguchi@bio.titech.ac.jp [Department of Biomolecular Engineering, Graduate School of Biosciences and Biotechnology, Tokyo Institute of Technology, B56, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501 (Japan)

    2011-02-25

    Research highlights: {yields} We develop a method to track a quantum dot-conjugated protein in yeast cells. {yields} We incorporate the conjugated quantum dot proteins into yeast spheroplasts. {yields} We track the motions by conventional or 3D tracking microscopy. -- Abstract: Yeast is a model eukaryote with a variety of biological resources. Here we developed a method to track a quantum dot (QD)-conjugated protein in the budding yeast Saccharomyces cerevisiae. We chemically conjugated QDs with the yeast prion Sup35, incorporated them into yeast spheroplasts, and tracked the motions by conventional two-dimensional or three-dimensional tracking microscopy. The method paves the way toward the individual tracking of proteins of interest inside living yeast cells.

  10. Behavioral synthesis of asynchronous circuits

    DEFF Research Database (Denmark)

    Nielsen, Sune Fallgaard

    2005-01-01

    domain by introducing a computation model, which resembles the synchronous datapath and control architecture, but which is completely asynchronous. The model contains the possibility for isolating some or all of the functional units by locking their respective inputs and outputs while the functional unit...

  11. A New Method for Tracking Individual Particles During Bed Load Transport in a Gravel-Bed River

    Science.gov (United States)

    Tremblay, M.; Marquis, G. A.; Roy, A. G.; Chaire de Recherche Du Canada En Dynamique Fluviale

    2010-12-01

    Many particle tracers (passive or active) have been developed to study gravel movement in rivers. It remains difficult, however, to document resting and moving periods and to know how particles travel from one deposition site to another. Our new tracking method uses the Hobo Pendant G acceleration Data Logger to quantitatively describe the motion of individual particles from the initiation of movement, through the displacement and to the rest, in a natural gravel river. The Hobo measures the acceleration in three dimensions at a chosen temporal frequency. The Hobo was inserted into 11 artificial rocks. The rocks were seeded in Ruisseau Béard, a small gravel-bed river in the Yamaska drainage basin (Québec) where the hydraulics, particle sizes and bed characteristics are well known. The signals recorded during eight floods (Summer and Fall 2008-2009) allowed us to develop an algorithm which classifies the periods of rest and motion. We can differentiate two types of motion: sliding and rolling. The particles can also vibrate while remaining in the same position. The examination of the movement and vibration periods with respect to the hydraulic conditions (discharge, shear stress, stream power) showed that vibration occurred mostly before the rise of hydrograph and allowed us to establish movement threshold and response times. In all cases, particle movements occurred during floods but not always in direct response to increased bed shear stress and stream power. This method offers great potential to track individual particles and to establish a spatiotemporal sequence of the intermittent transport of the particle during a flood and to test theories concerning the resting periods of particles on a gravel bed.

  12. Belief Consensus Algorithms for Distributed Target Tracking in Wireless Sensor Networks

    CERN Document Server

    Savic, Vladimir; Zazo, Santiago

    2012-01-01

    In distributed target tracking in wireless sensor networks (WSN), agreement on the target state is usually achieved by the construction and maintenance of a communication path. Such an approach lack robustness to failures, and is not applicable to asynchronous networks. Recently, methods have been proposed that can solve these problems using consensus algorithms. However, these methods suffer from at least one of the following problems: i) they do not use fastest consensus methods, and ii) they cannot handle all parametric and nonparametric likelihood functions. In this paper, we propose a general framework for target tracking using distributed particle filtering (DPF) based on three asynchronous belief consensus (BC) algorithms: standard belief consensus (SBC), broadcast gossip (BG), and belief propagation (BP). Since DPF can be also solved (without consensus) by exchanging the observed data, we determine under which conditions BC-based methods are preferred. Finally, we perform extensive simulations to anal...

  13. A C++ Framework for Conducting High-Speed, Long-Term Particle Tracking Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Kabel, A.C.; /SLAC

    2006-02-06

    For the purpose of conducting parallel, long-term tracking studies of storage rings such as the ones described in [3], [4], maximum execution speed is essential. We describe an approach involving metaprogramming techniques in C++ which results in execution speeds rivaling hand-optimized assembler code for a particular tracking lattice while retaining the generality and flexibility of an all-purpose tracking code.

  14. Developing new optical imaging techniques for single particle and molecule tracking in live cells

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wei [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    Differential interference contrast (DIC) microscopy is a far-field as well as wide-field optical imaging technique. Since it is non-invasive and requires no sample staining, DIC microscopy is suitable for tracking the motion of target molecules in live cells without interfering their functions. In addition, high numerical aperture objectives and condensers can be used in DIC microscopy. The depth of focus of DIC is shallow, which gives DIC much better optical sectioning ability than those of phase contrast and dark field microscopies. In this work, DIC was utilized to study dynamic biological processes including endocytosis and intracellular transport in live cells. The suitability of DIC microscopy for single particle tracking in live cells was first demonstrated by using DIC to monitor the entire endocytosis process of one mesoporous silica nanoparticle (MSN) into a live mammalian cell. By taking advantage of the optical sectioning ability of DIC, we recorded the depth profile of the MSN during the endocytosis process. The shape change around the nanoparticle due to the formation of a vesicle was also captured. DIC microscopy was further modified that the sample can be illuminated and imaged at two wavelengths simultaneously. By using the new technique, noble metal nanoparticles with different shapes and sizes were selectively imaged. Among all the examined metal nanoparticles, gold nanoparticles in rod shapes were found to be especially useful. Due to their anisotropic optical properties, gold nanorods showed as diffraction-limited spots with disproportionate bright and dark parts that are strongly dependent on their orientation in the 3D space. Gold nanorods were developed as orientation nanoprobes and were successfully used to report the self-rotation of gliding microtubules on kinesin coated substrates. Gold nanorods were further used to study the rotational motions of cargoes during the endocytosis and intracellular transport processes in live mammalian

  15. Intra-Nuclear Single-Particle Tracking (I-SPT) to Reveal the Functional Architecture of Chromosomes.

    Science.gov (United States)

    Récamier, Vincent

    2016-01-01

    Chromosome architecture needs to be investigated in relation with the chemical function of DNA. The kinetics of gene expression, DNA replication, and repair are driven by the mechanisms by which a functional nuclear protein finds its substrate in the nucleus. Single-particle tracking (SPT) is a method to quantify fluorescent molecules dynamics from the tracks of the single molecules recorded by high-resolution microscopes. SPT offers direct observation of the movement and single-molecule resolution. Usually SPT is performed on membranes because of higher contrast. Here, we introduce a novel method to record the trajectories of weakly fluorescent molecules in the nucleus of living cells. I-SPT uses some specific detection and analysis tools to enable the computation of reliable statistics on nuclear particle movement.

  16. Bedload transport in a formerly glaciated mountain catchment constrained by particle tracking

    Science.gov (United States)

    Dell'Agnese, A.; Brardinoni, F.; Toro, M.; Mao, L.; Engel, M.; Comiti, F.

    2015-11-01

    In formerly glaciated mountain settings, Pleistocene glaciations are responsible for profound spatial reorganization of the landscape structure. By imposing local channel slope and the degree of hillslope-channel connectivity, glacial macro-forms can exert first-order controls on the downstream strength and continuity of the coarse sediment cascade. To estimate quantitatively these controls we trace bedload transport for 3 years along Strimm Creek, Eastern Italian Alps. Specifically, we monitor the travel distance of 490 PIT-tagged particles (b axis: 23-229 mm; weight: 83-6525 g) at two contrasting sites: Upper Strimm Creek (US; 4 km2), which flows through a fluvially dominated hanging valley, and Lower Strimm Creek (LS; 7.5 km2), located downstream, in a relict glacial trough where it experiences periodic colluvial sediment inputs from lateral tributaries. Tracer positioning within the streambed is periodically tracked in the field with a portable antenna in order to assess progressive travel distances, as well as the extent of the channel active layer, in relation to snowmelt and rainfall-driven peak flows. Interestingly, we show that tracer virtual velocities for selected inter-survey periods are independent of tracer weight at both study sites. Cumulatively, tracers in US have travelled across distances (i.e. inner quartiles) shorter than 2 m, which correspond to over 2 orders of magnitude less than what was observed in LS. These figures translate, after calculations of tracer inter-survey virtual velocities, into estimated bedload volumes equal to about 3 m3 in US and 600 m3 in LS, with most of the transport (75 % in US, and 93 % in LS) occurring during snowmelt. A similar contrast in bedload transport rates, even without considering the additional volumes of material mobilized by mass-wasting processes in LS, testifies the extent to which the glacial imprinting can still affect contemporary sediment transfer, and thus postglacial landscape evolution, in

  17. Advanced algorithms for mobile robot motion planning and tracking in structured static environments using particle swarm optimization

    OpenAIRE

    Ćosić Aleksandar; Šušić Marko; Katić Duško

    2012-01-01

    An approach to intelligent robot motion planning and tracking in known and static environments is presented in this paper. This complex problem is divided into several simpler problems. The first is generation of a collision free path from starting to destination point, which is solved using a particle swarm optimization (PSO) algorithm. The second is interpolation of the obtained collision-free path, which is solved using a radial basis function neural network (RBFNN), and trajectory g...

  18. Tracking human position and lower body parts using Kalman and particle filters constrained by human biomechanics.

    Science.gov (United States)

    Martinez del Rincon, Jesús; Makris, Dimitrios; Orrite Urunuela, Carlos; Nebel, Jean-Christophe

    2011-02-01

    In this paper, a novel framework for visual tracking of human body parts is introduced. The approach presented demonstrates the feasibility of recovering human poses with data from a single uncalibrated camera by using a limb-tracking system based on a 2-D articulated model and a double-tracking strategy. Its key contribution is that the 2-D model is only constrained by biomechanical knowledge about human bipedal motion, instead of relying on constraints that are linked to a specific activity or camera view. These characteristics make our approach suitable for real visual surveillance applications. Experiments on a set of indoor and outdoor sequences demonstrate the effectiveness of our method on tracking human lower body parts. Moreover, a detail comparison with current tracking methods is presented.

  19. Asynchronous control for networked systems

    CERN Document Server

    Rubio, Francisco; Bencomo, Sebastián

    2015-01-01

    This book sheds light on networked control systems; it describes different techniques for asynchronous control, moving away from the periodic actions of classical control, replacing them with state-based decisions and reducing the frequency with which communication between subsystems is required. The text focuses specially on event-based control. Split into two parts, Asynchronous Control for Networked Systems begins by addressing the problems of single-loop networked control systems, laying out various solutions which include two alternative model-based control schemes (anticipatory and predictive) and the use of H2/H∞ robust control to deal with network delays and packet losses. Results on self-triggering and send-on-delta sampling are presented to reduce the need for feedback in the loop. In Part II, the authors present solutions for distributed estimation and control. They deal first with reliable networks and then extend their results to scenarios in which delays and packet losses may occur. The novel ...

  20. Eruptions on the fast track: application of Particle Tracking Velocimetry algorithms to visual and thermal high-speed videos of Strombolian explosions

    Science.gov (United States)

    Gaudin, Damien; Monica, Moroni; Jacopo, Taddeucci; Luca, Shindler; Piergiorgio, Scarlato

    2013-04-01

    Strombolian eruptions are characterized by mild, frequent explosions that eject gas and ash- to bomb-sized pyroclasts into the atmosphere. Studying these explosions is crucial, both for direct hazard assessment and for understanding eruption dynamics. Conventional thermal and optical imaging already allows characterizing several eruptive processes, but the quantification of key parameters linked to magma properties and conduit processes requires acquiring images at higher frequency. For example, high speed imaging already demonstrated how the size and the pressure of the gas bubble are linked to the decay of the ejection velocity of the particles, and the origin of the bombs, either fresh or recycled material, could be linked to their thermal evolution. However, the manual processing of the images is time consuming. Consequently, it does not allows neither the routine monitoring nor averaged statistics, since only a few relevant particles - usually the fastest - of a few explosions can be taken into account. In order to understand the dynamics of strombolian eruption, and particularly their cyclic behavior, the quantification of the total mass, heat and energy discharge are a crucial point. In this study, we use a Particle Tracking Velocimetry (PTV) algorithm jointly to traditional images processing to automatically extract the above parameters from visible and thermal high-speed videos of individual Strombolian explosions. PTV is an analysis technique where each single particle is detected and tracked during a series of images. Velocity, acceleration, and temperature can then be deduced and time averaged to get an extensive overview of each explosion. The suitability of PTV and its potential limitations in term of detection and representativity is investigated in various explosions of Stromboli (Italy), Yasur (Vanuatu) and Fuego (Guatemala) volcanoes. On most event, multiple sub-explosion are visible. In each sub-explosion, trends are noticeable : (1) the ejection

  1. Asynchronous MPI for the Masses

    OpenAIRE

    Wittmann, Markus; Hager, Georg; Zeiser, Thomas; Wellein, Gerhard

    2013-01-01

    We present a simple library which equips MPI implementations with truly asynchronous non-blocking point-to-point operations, and which is independent of the underlying communication infrastructure. It utilizes the MPI profiling interface (PMPI) and the MPI_THREAD_MULTIPLE thread compatibility level, and works with current versions of Intel MPI, Open MPI, MPICH2, MVAPICH2, Cray MPI, and IBM MPI. We show performance comparisons on a commodity InfiniBand cluster and two tier-1 systems in Germany...

  2. Simultaneous Multi-vehicle Detection and Tracking Framework with Pavement Constraints Based on Machine Learning and Particle Filter Algorithm

    Institute of Scientific and Technical Information of China (English)

    WANG Ke; HUANG Zhi; ZHONG Zhihua

    2014-01-01

    Due to the large variations of environment with ever-changing background and vehicles with different shapes, colors and appearances, to implement a real-time on-board vehicle recognition system with high adaptability, efficiency and robustness in complicated environments, remains challenging. This paper introduces a simultaneous detection and tracking framework for robust on-board vehicle recognition based on monocular vision technology. The framework utilizes a novel layered machine learning and particle filter to build a multi-vehicle detection and tracking system. In the vehicle detection stage, a layered machine learning method is presented, which combines coarse-search and fine-search to obtain the target using the AdaBoost-based training algorithm. The pavement segmentation method based on characteristic similarity is proposed to estimate the most likely pavement area. Efficiency and accuracy are enhanced by restricting vehicle detection within the downsized area of pavement. In vehicle tracking stage, a multi-objective tracking algorithm based on target state management and particle filter is proposed. The proposed system is evaluated by roadway video captured in a variety of traffics, illumination, and weather conditions. The evaluating results show that, under conditions of proper illumination and clear vehicle appearance, the proposed system achieves 91.2% detection rate and 2.6% false detection rate. Experiments compared to typical algorithms show that, the presented algorithm reduces the false detection rate nearly by half at the cost of decreasing 2.7%–8.6% detection rate. This paper proposes a multi-vehicle detection and tracking system, which is promising for implementation in an on-board vehicle recognition system with high precision, strong robustness and low computational cost.

  3. Flow Mapping in a Gas-Solid Riser via Computer Automated Radioactive Particle Tracking (CARPT)

    Energy Technology Data Exchange (ETDEWEB)

    Muthanna Al-Dahhan; Milorad P. Dudukovic; Satish Bhusarapu; Timothy J. O' hern; Steven Trujillo; Michael R. Prairie

    2005-06-04

    Statement of the Problem: Developing and disseminating a general and experimentally validated model for turbulent multiphase fluid dynamics suitable for engineering design purposes in industrial scale applications of riser reactors and pneumatic conveying, require collecting reliable data on solids trajectories, velocities ? averaged and instantaneous, solids holdup distribution and solids fluxes in the riser as a function of operating conditions. Such data are currently not available on the same system. Multiphase Fluid Dynamics Research Consortium (MFDRC) was established to address these issues on a chosen example of circulating fluidized bed (CFB) reactor, which is widely used in petroleum and chemical industry including coal combustion. This project addresses the problem of lacking reliable data to advance CFB technology. Project Objectives: The objective of this project is to advance the understanding of the solids flow pattern and mixing in a well-developed flow region of a gas-solid riser, operated at different gas flow rates and solids loading using the state-of-the-art non-intrusive measurements. This work creates an insight and reliable database for local solids fluid-dynamic quantities in a pilot-plant scale CFB, which can then be used to validate/develop phenomenological models for the riser. This study also attempts to provide benchmark data for validation of Computational Fluid Dynamic (CFD) codes and their current closures. Technical Approach: Non-Invasive Computer Automated Radioactive Particle Tracking (CARPT) technique provides complete Eulerian solids flow field (time average velocity map and various turbulence parameters such as the Reynolds stresses, turbulent kinetic energy, and eddy diffusivities). It also gives directly the Lagrangian information of solids flow and yields the true solids residence time distribution (RTD). Another radiation based technique, Computed Tomography (CT) yields detailed time averaged local holdup profiles at

  4. Particle Filtering for Obstacle Tracking in UAS Sense and Avoid Applications

    OpenAIRE

    Anna Elena Tirri; Giancarmine Fasano; Domenico Accardo; Antonio Moccia

    2014-01-01

    Obstacle detection and tracking is a key function for UAS sense and avoid applications. In fact, obstacles in the flight path must be detected and tracked in an accurate and timely manner in order to execute a collision avoidance maneuver in case of collision threat. The most important parameter for the assessment of a collision risk is the Distance at Closest Point of Approach, that is, the predicted minimum distance between own aircraft and intruder for assigned current position and speed. ...

  5. Use of a ground-water flow model with particle tracking to evaluate ground-water vulnerability, Clark County, Washington

    Science.gov (United States)

    Snyder, D.T.; Wilkinson, J.M.; Orzol, L.L.

    1996-01-01

    A ground-water flow model was used in conjunction with particle tracking to evaluate ground-water vulnerability in Clark County, Washington. Using the particle-tracking program, particles were placed in every cell of the flow model (about 60,000 particles) and tracked backwards in time and space upgradient along flow paths to their recharge points. A new computer program was developed that interfaces the results from a particle-tracking program with a geographic information system (GIS). The GIS was used to display and analyze the particle-tracking results. Ground-water vulnerability was evaluated by selecting parts of the ground-water flow system and combining the results with ancillary information stored in the GIS to determine recharge areas, characteristics of recharge areas, downgradient impact of land use at recharge areas, and age of ground water. Maps of the recharge areas for each hydrogeologic unit illustrate the presence of local, intermediate, or regional ground-water flow systems and emphasize the three-dimensional nature of the ground-water flow system in Clark County. Maps of the recharge points for each hydrogeologic unit were overlaid with maps depicting aquifer sensitivity as determined by DRASTIC (a measure of the pollution potential of ground water, based on the intrinsic characteristics of the near-surface unsaturated and saturated zones) and recharge from on-site waste-disposal systems. A large number of recharge areas were identified, particularly in southern Clark County, that have a high aquifer sensitivity, coincide with areas of recharge from on-site waste-disposal systems, or both. Using the GIS, the characteristics of the recharge areas were related to the downgradient parts of the ground-water system that will eventually receive flow that has recharged through these areas. The aquifer sensitivity, as indicated by DRASTIC, of the recharge areas for downgradient parts of the flow system was mapped for each hydrogeologic unit. A number of

  6. Confocal fluorescent imaging of tracks from heavy charged particles utilising new Al2O3:C,Mg crystals.

    Science.gov (United States)

    Akselrod, Mark S; Yoder, R Craig; Akselrod, Gleb M

    2006-01-01

    A completely optical, non-destructive imaging of tracks in a fluorescent crystal provides a new way to detect and to assess doses from heavy charged particles and neutrons. The technique combines confocal fluorescent microscopy with a new radiation-sensitive, luminescent material based on aluminium oxide single crystals doped with carbon, magnesium and having aggregate oxygen vacancy defects (Al2O3:C,Mg). Radiation-induced colour centres in the new material have an absorption band at 620 nm and produce fluorescence at 750 nm with a high quantum yield and a short, 75 +/- 5 ns, fluorescence lifetime. Three-dimensional spatial distribution of fluorescent intensity allows one to obtain depth-dose distributions and to discriminate between high- and low-linear energy transfer radiations. Images of single tracks produced by different types of radiation have been obtained. Irradiations with a calibrated 241Am alpha source showed high efficiency for track detection. Thermal neutrons were detected using a nuclear reaction with a 6LiF radiator and production of alpha particles and tritium ions. Fast neutrons were detected using recoil protons produced in a polyethylene radiator installed in front of the crystalline detector. Three-dimensional reconstruction of a recoil proton propagating through the crystal was demonstrated. PMID:16644943

  7. Confocal fluorescent imaging of tracks from heavy charged particles utilising new Al2O3:C,Mg crystals

    International Nuclear Information System (INIS)

    A completely optical, non-destructive imaging of tracks in a fluorescent crystal provides a new way to detect and to assess doses from heavy charged particles and neutrons. The technique combines confocal fluorescent microscopy with a new radiation-sensitive, luminescent material based on aluminium oxide single crystals doped with carbon, magnesium and having aggregate oxygen vacancy defects (Al2O3:C,Mg). Radiation-induced colour centres in the new material have an absorption band at 620 nm and produce fluorescence at 750 nm with a high quantum yield and a short, 75 ± 5 ns, fluorescence lifetime. Three-dimensional spatial distribution of fluorescent intensity allows one to obtain depth-dose distributions and to discriminate between high- and low-linear energy transfer radiations. Images of single tracks produced by different types of radiation have been obtained. Irradiations with a calibrated 241Am alpha source showed high efficiency for track detection. Thermal neutrons were detected using a nuclear reaction with a 6LiF radiator and production of alpha particles and tritium ions. Fast neutrons were detected using recoil protons produced in a polyethylene radiator installed in front of the crystalline detector. Three-dimensional reconstruction of a recoil proton propagating through the crystal was demonstrated. (authors)

  8. Asynchronous Methods for Deep Reinforcement Learning

    OpenAIRE

    Mnih, Volodymyr; Badia, Adrià Puigdomènech; Mirza, Mehdi; Graves, Alex; Lillicrap, Timothy P.; Harley, Tim; Silver, David; Kavukcuoglu, Koray

    2016-01-01

    We propose a conceptually simple and lightweight framework for deep reinforcement learning that uses asynchronous gradient descent for optimization of deep neural network controllers. We present asynchronous variants of four standard reinforcement learning algorithms and show that parallel actor-learners have a stabilizing effect on training allowing all four methods to successfully train neural network controllers. The best performing method, an asynchronous variant of actor-critic, surpasse...

  9. Kernel density estimation and marginalized-particle based probability hypothesis density filter for multi-target tracking

    Institute of Scientific and Technical Information of China (English)

    张路平; 王鲁平; 李飚; 赵明

    2015-01-01

    In order to improve the performance of the probability hypothesis density (PHD) algorithm based particle filter (PF) in terms of number estimation and states extraction of multiple targets, a new probability hypothesis density filter algorithm based on marginalized particle and kernel density estimation is proposed, which utilizes the idea of marginalized particle filter to enhance the estimating performance of the PHD. The state variables are decomposed into linear and non-linear parts. The particle filter is adopted to predict and estimate the nonlinear states of multi-target after dimensionality reduction, while the Kalman filter is applied to estimate the linear parts under linear Gaussian condition. Embedding the information of the linear states into the estimated nonlinear states helps to reduce the estimating variance and improve the accuracy of target number estimation. The meanshift kernel density estimation, being of the inherent nature of searching peak value via an adaptive gradient ascent iteration, is introduced to cluster particles and extract target states, which is independent of the target number and can converge to the local peak position of the PHD distribution while avoiding the errors due to the inaccuracy in modeling and parameters estimation. Experiments show that the proposed algorithm can obtain higher tracking accuracy when using fewer sampling particles and is of lower computational complexity compared with the PF-PHD.

  10. Neutron response calculation on the basis of variable track etch rates along the secondary particle trajectories in CR-39

    CERN Document Server

    Hermsdorf, D; Dörschel, B; Henniger, J

    1999-01-01

    The calculation of the response of CR-39 detectors exposed to neutrons is of high importance for their dosimetric application. A computer code system has been developed for this purpose. Whereas the generation of secondary charged particles is carried out using non-analogue Monte-Carlo techniques with variance reduction the simulation of the track formation process is treated without any free parameter starting from the etch rate ratio V(REL) only. Results are given for the contribution of recoil protons to the response as a function of the neutron energy and angle of incidence. Furthermore, the influence of an external radiator has been studied. The comparison of the calculated values with experimental data confirm the reliability of the track etch model applied.

  11. A Rao-Blackwellized particle filter for joint parameter estimation and biomass tracking in a stochastic predator-prey system.

    Science.gov (United States)

    Martín-Fernández, Laura; Gilioli, Gianni; Lanzarone, Ettore; Miguez, Joaquin; Pasquali, Sara; Ruggeri, Fabrizio; Ruiz, Diego P

    2014-06-01

    Functional response estimation and population tracking in predator-prey systems are critical problems in ecology. In this paper we consider a stochastic predator-prey system with a Lotka-Volterra functional response and propose a particle filtering method for: (a) estimating the behavioral parameter representing the rate of effective search per predator in the functional response and (b) forecasting the population biomass using field data. In particular, the proposed technique combines a sequential Monte Carlo sampling scheme for tracking the time-varying biomass with the analytical integration of the unknown behavioral parameter. In order to assess the performance of the method, we show results for both synthetic and observed data collected in an acarine predator-prey system, namely the pest mite Tetranychus urticae and the predatory mite Phytoseiulus persimilis. PMID:24506552

  12. Advanced algorithms for mobile robot motion planning and tracking in structured static environments using particle swarm optimization

    Directory of Open Access Journals (Sweden)

    Ćosić Aleksandar

    2012-01-01

    Full Text Available An approach to intelligent robot motion planning and tracking in known and static environments is presented in this paper. This complex problem is divided into several simpler problems. The first is generation of a collision free path from starting to destination point, which is solved using a particle swarm optimization (PSO algorithm. The second is interpolation of the obtained collision-free path, which is solved using a radial basis function neural network (RBFNN, and trajectory generation, based on the interpolated path. The last is a trajectory tracking problem, which is solved using a proportional-integral (PI controller. Due to uncertainties, obstacle avoidance is still not ensured, so an additional fuzzy controller is introduced, which corrects the control action of the PI controller. The proposed solution can be used even in dynamic environments, where obstacles change their position in time. Simulation studies were realized to validate and illustrate this approach.

  13. Single-particle tracking of immunoglobulin E receptors (FcεRI) in micron-sized clusters and receptor patches.

    Science.gov (United States)

    Spendier, Kathrin; Lidke, Keith A; Lidke, Diane S; Thomas, James L

    2012-02-17

    When mast cells contact a monovalent antigen-bearing fluid lipid bilayer, IgE-loaded FcεRI receptors aggregate at contact points and trigger degranulation and the release of immune activators. We used two-color total internal reflection fluorescence microscopy and single-particle tracking to show that most fluorescently labeled receptor complexes diffuse freely within these micron-size clusters, with a diffusion coefficient comparable to free receptors in resting cells. At later times, when the small clusters coalesce to form larger patches, receptors diffuse even more rapidly. In all cases, Monte Carlo diffusion simulations ensured that the tracking results were free of bias, and distinguished biological from statistical variation. These results show the diversity in receptor mobility in mast cells, demonstrating at least three distinct states of receptor diffusivity.

  14. A comparison of single particle tracking and temporal image correlation spectroscopy for quantitative analysis of endosome motility

    DEFF Research Database (Denmark)

    Lund, F. W.; Wustner, D.

    2013-01-01

    Single particle tracking (SPT) is becoming a standard method to extract transport parameters from time-lapse image sequences of fluorescent vesicles in living cells. Another method to obtain these data is temporal image correlation spectroscopy (TICS), but this method is less often used for measu......Single particle tracking (SPT) is becoming a standard method to extract transport parameters from time-lapse image sequences of fluorescent vesicles in living cells. Another method to obtain these data is temporal image correlation spectroscopy (TICS), but this method is less often used...... for measurement of intracellular vesicle transport. Here, we present an extensive comparison of SPT and TICS. First we examine the effect of photobleaching, shading and noise on SPT and TICS analysis using simulated image sequences. To this end, we developed a simple photophysical model, which relates spatially...... varying illumination intensity to the bleaching propensity and fluorescence intensity of the moving particles. We found that neither SPT nor TICS are affected by photobleaching per se, but the transport parameters obtained by both methods are sensitive to the signal-to-noise ratio. In addition, the number...

  15. A novel asynchronous access method with binary interfaces

    Directory of Open Access Journals (Sweden)

    Torres-Solis Jorge

    2008-10-01

    Full Text Available Abstract Background Traditionally synchronous access strategies require users to comply with one or more time constraints in order to communicate intent with a binary human-machine interface (e.g., mechanical, gestural or neural switches. Asynchronous access methods are preferable, but have not been used with binary interfaces in the control of devices that require more than two commands to be successfully operated. Methods We present the mathematical development and evaluation of a novel asynchronous access method that may be used to translate sporadic activations of binary interfaces into distinct outcomes for the control of devices requiring an arbitrary number of commands to be controlled. With this method, users are required to activate their interfaces only when the device under control behaves erroneously. Then, a recursive algorithm, incorporating contextual assumptions relevant to all possible outcomes, is used to obtain an informed estimate of user intention. We evaluate this method by simulating a control task requiring a series of target commands to be tracked by a model user. Results When compared to a random selection, the proposed asynchronous access method offers a significant reduction in the number of interface activations required from the user. Conclusion This novel access method offers a variety of advantages over traditionally synchronous access strategies and may be adapted to a wide variety of contexts, with primary relevance to applications involving direct object manipulation.

  16. Accurate calculation of Stokes drag for point-particle tracking in two-way coupled flows

    Science.gov (United States)

    Horwitz, J. A. K.; Mani, A.

    2016-08-01

    In this work, we propose and test a method for calculating Stokes drag applicable to particle-laden fluid flows where two-way momentum coupling is important. In the point-particle formulation, particle dynamics are coupled to fluid dynamics via a source term that appears in the respective momentum equations. When the particle Reynolds number is small and the particle diameter is smaller than the fluid scales, it is common to approximate the momentum coupling source term as the Stokes drag. The Stokes drag force depends on the difference between the undisturbed fluid velocity evaluated at the particle location, and the particle velocity. However, owing to two-way coupling, the fluid velocity is modified in the neighborhood of a particle, relative to its undisturbed value. This causes the computed Stokes drag force to be underestimated in two-way coupled point-particle simulations. We develop estimates for the drag force error as function of the particle size relative to the grid size. Because the disturbance field created by the particle contaminates the surrounding fluid, correctly calculating the drag force cannot be done solely by direct interpolation of the fluid velocity. Instead, we develop a correction method that calculates the undisturbed fluid velocity from the computed disturbed velocity field by adding an estimate of the velocity disturbance created by the particle. The correction scheme is tested for a particle settling in an otherwise quiescent fluid and is found to reduce the error in computed settling velocity by an order of magnitude compared with common interpolation schemes.

  17. Detection of accelerated particles from pulsed plasma discharge using solid state nuclear track detector

    Indian Academy of Sciences (India)

    G M El-Aragi; U Seddik; A Abd El-Haliem

    2007-04-01

    The ion beam of a Mather-type 23.25 J plasma focus device operated with air filling at 10 Torr was registered using CR-39 nuclear track detector. The irradiated samples were etched in NaOH solution at 70°C for 1 h. It is found here that plasma beam contains multi-components of microbeams. The individual track density of microbeams is estimated and the total current density of the plasma stream is measured to be 1.2 mA/cm2. A model for counting the track density of individual microbeams is proposed here. Faraday cup measurements showed the ion pulse with energy ranging from 5.8 keV to 3.3 keV.

  18. Articulated Hand Motion Tracking Using ICA-based Motion Analysis and Particle Filtering

    Directory of Open Access Journals (Sweden)

    Makoto Kato

    2006-06-01

    Full Text Available This paper introduces a new representation of hand motions for tracking and recognizing hand-finger gestures in an image sequence. A human hand has many joints, for example our hand model has 15, and its high dimensionality makes it difficult to model hand motions. To make things easier, it is important to represent a hand motion in a low dimensional space. Principle component analysis (PCA has been proposed to reduce the dimensionality. However, the PCA basis vectors only represent global features, which are not optimal for representing intrinsic features. This paper proposes an efficient representation of hand motions by independent component analysis (ICA. The ICA basis vectors represent local features, each of which corresponds to the motion of a particular finger. This representation is more efficient in modeling hand motions for tracking and recognizing handfinger gestures in an image sequence. We will demonstrate the effectiveness of the method by tracking a hand in real image sequences.

  19. Design and simulation of track/hold circuit with CMOS FET for particle detector

    International Nuclear Information System (INIS)

    In this paper, the objective is to realize a Track/Hold Circuit for silicon strip, Si(Li), CdZnTe and CsI detectors etc. By using CMOS transistor to implement various components in electronic circuit, the Track and Hold circuit only made with CMOS FET is succeeded to be designed and simulated. Performance was characterized using PSPICE simulator with BSIMV3.3 parameters of the Proteus. Several measurements of acquisition time can be made from 60 ns to 4.44 μs related to the output resistance, and the integral nonlinearity is good. (authors)

  20. Particle track membranes and their applications. Proceedings of the 2. Meeting 2-6 December 1991, Szczyrk, Poland

    International Nuclear Information System (INIS)

    The materials (16 papers) of the meeting present the activities of leading European institutions being engaged in the interesting topic. Technologies and methods of PTM (particle track membranes) production by interaction of ion beams with polymeric materials have been broadly discussed. The spectrum of polymeric foils, their applicability as PTM and their properties after irradiation in different conditions have been shown as well. A number of possible applications of PTM and already tested and realized in industry, medicine, biology and physical investigations have also been presented

  1. A novel particle tracking and break-up detection algorithm: application to the turbulent break-up of bubbles

    OpenAIRE

    Rodríguez Rodríguez, Javier; Martínez Bazán, Carlos; Montañés García, José Luis

    2003-01-01

    A new method has been developed to measure experimentally the break-up properties of bubbles. The technique is based on the application of a particle tracking velocimetry algorithm to high-speed video images not only to measure the velocity of the bubbles, but also to detect the break-up events. Thus the algorithm is able to associate every broken bubble with the daughter bubbles formed upon their corresponding break-up. Moreover, the lifetime, as well as the number and size of fragments resu...

  2. Particle tracking velocimetry and particle image velocimetry study of the slow motion of rough and smooth solid spheres in a yield-stress fluid.

    Science.gov (United States)

    Holenberg, Yulia; Lavrenteva, Olga M; Shavit, Uri; Nir, Avinoam

    2012-12-01

    We report experimental evidence of an effect opposite to the "solidification" of small bubbles in liquid where the surface can become immobile. Namely, it is demonstrated that smooth solid spheres falling in a yield-stress fluid under the action of gravity can behave similar to drops. Particle tracking velocimetry was used to determine the shape of the yielded region around solid spherical particles undergoing slow stationary motion in 0.07% w/w Carbopol gel due to gravity under creeping flow conditions. The flow field inside the yielded region was determined by particle image velocimetry. It was found that the shape of the yielded region and the flow field around slow-moving rough particles is similar to the published results of numerical simulations, whereas those around smooth spheres resemble the experimental results obtained for viscous drops. The effect was explained by a slip of the gel on the smooth surface. Most likely, the slip originated from seepage of clean water from the gel, forming a thin lubricating layer near the solid surface.

  3. Dissecting the Cell Entry Pathway of Dengue Virus by Single-Particle Tracking in Living Cells

    NARCIS (Netherlands)

    van der Schaar, Hilde M.; Rust, Michael J.; Chen, Chen; van der Ende-Metselaar, Heidi; Wilschut, Jan; Zhuang, Xiaowei; Smit, Jolanda M.

    2008-01-01

    Dengue virus (DENV) is an enveloped RNA virus that causes the most common arthropod-borne infection worldwide. The mechanism by which DENV infects the host cell remains unclear. In this work, we used live-cell imaging and single-virus tracking to investigate the cell entry, endocytic trafficking, an

  4. Infrared Spectroscopy of Wild 2 Particle Hypervelocity Tracks in Stardust Aerogel: Evidence for the presence of Volatile Organics in Comet Dust

    Energy Technology Data Exchange (ETDEWEB)

    Bajt, S; Sandford, S A; Flynn, G J; Matrajt, G; Snead, C J; Westphal, A J; Bradley, J P

    2007-08-28

    Infrared spectroscopy maps of some tracks, made by cometary dust from 81P/Wild 2 impacting Stardust aerogel, reveal an interesting distribution of volatile organic material. Out of six examined tracks three show presence of volatile organic components possibly injected into the aerogel during particle impacts. When particle tracks contained excess volatile organic material, they were found to be -CH{sub 2}-rich. Off-normal particle tracks could indicate impacts by lower velocity particles that could have bounced off the Whipple shield, therefore carry off some contamination from it. However, this theory is not supported by data that show excess organic-rich material in normal and off-normal particle tracks. It is clear that the population of cometary particles impacting the Stardust aerogel collectors also include grains that contained little or none of this volatile organic component. This observation is consistent with the highly heterogeneous nature of the collected grains, as seen by a multitude of other analytical techniques. We propose that at least some of the volatile organic material might be of cometary origin based on supporting data shown in this paper. However, we also acknowledge the presence of carbon (primarily as -CH{sub 3}) in the original aerogel, which complicates interpretation of these results.

  5. Asynchronous Parallelization of a CFD Solver

    Directory of Open Access Journals (Sweden)

    Daniel S. Abdi

    2015-01-01

    Full Text Available A Navier-Stokes equations solver is parallelized to run on a cluster of computers using the domain decomposition method. Two approaches of communication and computation are investigated, namely, synchronous and asynchronous methods. Asynchronous communication between subdomains is not commonly used in CFD codes; however, it has a potential to alleviate scaling bottlenecks incurred due to processors having to wait for each other at designated synchronization points. A common way to avoid this idle time is to overlap asynchronous communication with computation. For this to work, however, there must be something useful and independent a processor can do while waiting for messages to arrive. We investigate an alternative approach of computation, namely, conducting asynchronous iterations to improve local subdomain solution while communication is in progress. An in-house CFD code is parallelized using message passing interface (MPI, and scalability tests are conducted that suggest asynchronous iterations are a viable way of parallelizing CFD code.

  6. Improved Particle Filter for Passive Target Tracking%改进粒子滤波在被动目标跟踪中的应用

    Institute of Scientific and Technical Information of China (English)

    邓小龙; 谢剑英; 杨煜普

    2005-01-01

    As a new method for dealing with any nonlinear or non-Gaussian distributions, based on the Monte Carlo methods and Bayesian filtering, particle filters (PF) are favored by researchers and widely applied in many fields. Based on particle filtering, an improved extended Kalman filter (EKF) proposal distribution is presented. Evaluation of the weights is simplified and other improved techniques including the residual resampling step and Markov Chain Monte Carlo method are introduced for target tracking. Performances of the EKF, basic PF and the improved PF are compared in target tracking examples. The simulation results confirm that the improved particle filter outperforms the others.

  7. Tracking control of colloidal particles through non-homogeneous stationary flows.

    Science.gov (United States)

    Híjar, Humberto

    2013-12-21

    We consider the problem of controlling the trajectory of a single colloidal particle in a fluid with steady non-homogeneous flow. We use a Langevin equation to describe the dynamics of this particle, where the friction term is assumed to be given by the Faxén's Theorem for the force on a sphere immersed in a stationary flow. We use this description to propose an explicit control force field to be applied on the particle such that it will follow asymptotically any given desired trajectory, starting from an arbitrary initial condition. We show that the dynamics of the controlled particle can be mapped into a set of stochastic harmonic oscillators and that the velocity gradient of the solvent induces an asymmetric coupling between them. We study the particular case of a Brownian particle controlled through a plane Couette flow and show explicitly that the velocity gradient of the solvent renders the dynamics non-stationary and non-reversible in time. We quantify this effect in terms of the correlation functions for the position of the controlled particle, which turn out to exhibit contributions depending exclusively on the non-equilibrium character of the state of the solvent. In order to test the validity of our model, we perform simulations of the controlled particle moving in a simple shear flow, using a hybrid method combining molecular dynamics and multi-particle collision dynamics. We confirm numerically that the proposed guiding force allows for controlling the trajectory of the micro-sized particle by obligating it to follow diverse specific trajectories in fluids with homogeneous shear rates of different strengths. In addition, we find that the non-equilibrium correlation functions in simulations exhibit the same qualitative behavior predicted by the model, thus revealing the presence of the asymmetric non-equilibrium coupling mechanism induced by the velocity gradient.

  8. Scale-Dependent Fracture-Matrix Interactions and Their Impact on Radionuclide Transport: Development of efficient particle-tracking methods

    Energy Technology Data Exchange (ETDEWEB)

    Rajaram, Harihar [University of Colorado, Boulder; Brutz, Michael [University of Colorado, Boulder; Klein, Dylan R [University of Colorado, Boulder; Mallikamas, Wasin [University of Colorado, Boulder

    2014-09-18

    Matrix Diffusion and Adsorption within a rock matrix are important mechanisms for retarding transport of radionuclides in fractured rock. Due to computational limitations and difficulties in characterizing complex subsurface systems, diffusive exchange between a fracture network and surrounding rock matrix is often modeled using simplified conceptual representations. There is significant uncertainty in “effective” parameters used in these models, such as the “effective matrix diffusivity”. Often, these parameters are estimated by fitting sparse breakthrough data, and estimated values fall outside meaningful ranges, because simplified interpretive models do not consider complex three-dimensional flow. There is limited understanding of the relationship between the effective parameters and rock mass characteristics including network structure and matrix properties. There is also evidence for an apparent scale-dependence in “effective matrix diffusion” coefficients. These observations raise questions on whether fracture-matrix interaction parameters estimated from small-scale tracer tests can be used for predicting radionuclide fate and transport at the scale of DOE field sites. High-resolution three-dimensional Discrete-Fracture-Network-Matrix (DFNM) models based on well-defined local scale transport equations can help to address some of these questions. Due to tremendous advances in computational technology over the last 10 years, DFNM modeling in relatively large domains is now feasible. The overarching objective of our research is to use DFNM modeling to improve fundamental understanding of how effective parameters in conceptual models are related to fracture network structure and matrix properties. An advanced three-dimensional DFNM model is being developed, which combines upscaled particle-tracking algorithms for fracture-matrix interaction and a parallel fracture-network flow simulator. The particle-tracking algorithms allow complexity in flow fields

  9. Model Selection Coupled with a Particle Tracking Proxy Using Surface Deformation Data for Monitoring CO2 Plume Migration

    Science.gov (United States)

    Min, B.; Nwachukwu, A.; Srinivasan, S.; Wheeler, M. F.

    2015-12-01

    This study formulates a framework of a model selection that refines geological models for monitoring CO2 plume migration. Special emphasis is placed on CO2 injection, and the particular techniques that are used for this study including model selection, particle tracking proxies, and partial coupling of flow and geomechanics. The proposed process starts with generating a large initial ensemble of reservoir models that reflect a prior uncertainty in reservoir description, including all plausible geologic scenarios. These models are presumed to be conditioned to available static data. In the absence of production or injection data, all prior reservoir models are regarded as equiprobable. Thus, the model selection algorithm is applied to select a few representative reservoir models that are more consistent with observed dynamic responses. A quick assessment of the models must then be performed to evaluate their dynamic characteristics and flow connectivity. This approach develops a particle tracking proxy and a finite element method solver for solving the flow equation and the stress problem, respectively. The shape of CO2 plume is estimated using a particle-tracking proxy that serves as a fast approximation of finite-difference simulation models. Sequentially, a finite element method solver is coupled with the proxy for analyzing geomechanical effects resulting from CO2 injection. A method is then implemented to group the models into clusters based on similarities in the estimated responses. The posterior model set is chosen as the cluster that produces the minimum deviation from the observed field data. The efficacy of non-dominated sorting based on Pareto-optimality is also tested in the current model selection framework. The proposed scheme is demonstrated on a carbon sequestration project in Algeria. Coupling surface deformation data with well injection data enhances the efficiency of tracking the CO2 plume. Therefore, this algorithm provides a probabilistic

  10. Applications of particle-tracking techniques to bank infiltration: a case study from El Paso, Texas, USA

    Science.gov (United States)

    Abdel-Fattah, Ahmad; Langford, Richard; Schulze-Makuch, Dirk

    2008-08-01

    This paper presents results of a small scale study that utilized particle-tracking techniques to evaluate transport of river water through an alluvial aquifer in a bank infiltration testing site in El Paso, Texas, USA. The particle-tracking survey was used to better define filtration parameters. Several simulations were generated to allow visualization of the effects of well placement and pumping rate on flow paths, travel time, the size of the pumping influence zone, and proportion of river-derived water and groundwater mixing in the pumping well. Simulations indicate that migration of river water into the aquifer is generally slow. Most water does not arrive at the well by the end of an 18-day pumping period at 0.54 m3/min pumping rate for a well located 18 m from the river. Forty-four percent of the water pumped from the well was river water. The models provided important information needed to design appropriate sampling schedules for bank filtration practices and ensured meeting adequate soil-retention times. The pumping rate has more effect on river water travel time than the location of the pumping well from the river. The examples presented in this paper indicate that operating the pumping well at a doubled distance from the river increased the time required for the water to travel to the well, but did not greatly change the capture zone.

  11. Use of plastic optical fibers for charged particle tracking in high energy physics

    International Nuclear Information System (INIS)

    A large tracking detector consisting of scintillating plastic optical fibers has been chosen by the DO collaboration as a part of a planned upgrade at the Fermilab Tevatron. The tracker will utilize a state of the art photodetector known as the Visible Light Photon Counter. The benefits of fiber tracking in high energy physics will be presented along with recent progress in several key areas, including: optimization of scintillating dyes and light yields, fiber construction, fiber ribbon manufacture and placement, optical transmission and photodetection. The current status of the D0 development effort will be outlined, including results from the characterization of 5,000 channels of VLPC. Finally, results from simulations of expected detector performance will be shown and discussed

  12. 3D silicon sensors with variable electrode depth for radiation hard high resolution particle tracking

    International Nuclear Information System (INIS)

    3D sensors, with electrodes micro-processed inside the silicon bulk using Micro-Electro-Mechanical System (MEMS) technology, were industrialized in 2012 and were installed in the first detector upgrade at the LHC, the ATLAS IBL in 2014. They are the radiation hardest sensors ever made. A new idea is now being explored to enhance the three-dimensional nature of 3D sensors by processing collecting electrodes at different depths inside the silicon bulk. This technique uses the electric field strength to suppress the charge collection effectiveness of the regions outside the p-n electrodes' overlap. Evidence of this property is supported by test beam data of irradiated and non-irradiated devices bump-bonded with pixel readout electronics and simulations. Applications include High-Luminosity Tracking in the high multiplicity LHC forward regions. This paper will describe the technical advantages of this idea and the tracking application rationale

  13. Initial recombination in the track of heavy charged particles: Numerical solution for air filled ionization chambers

    DEFF Research Database (Denmark)

    Kaiser, Franz-Joachim; Bassler, Niels; Tölli, Heikki;

    2012-01-01

    Introduction Modern particle therapy facilities enable sub-millimeter precision in dose deposition. Here, also ionization chambers (ICs) are used, which requires knowledge of the recombination effects. Up to now, recombination is corrected using phenomenological approaches for practical reasons. ...

  14. Dynamic melting and impurity particle tracking in continuously adjustable AC magnetic field

    Science.gov (United States)

    Bojarevics, V.; Pericleous, K.

    2016-07-01

    The analysis of semi-levitation melting is extended to account for the presence of particles (impurities, broken metal dendrite agglomerates, bubbles) during the full melting cycle simulated numerically using the pseudo-spectral schemes. The AC coil is dynamically moving with the melt front progress, while the generated Joule heat serves to enhance the melting rate. The electromagnetic force is decomposed into the time average and the oscillating parts. The time average effects on the particle transport are investigated previously using approximations derived for a locally uniform magnetic field. This paper presents expressions for the skin-layer type of the AC force containing also the pulsating part which contributes to the particle drag by the ‘history’ and ‘added mass’ contributions. The intense turbulence in the bulk of molten metal additionally contributes to the particle dispersion. The paper attempts to demonstrate the importance of each of the mentioned effects onto the particle transport during the melting until the final pouring stage. The method could be extended to similar AC field controlled melting/solidification processes.

  15. Direct multi-scale reconstruction of velocity fields from measurements of particle tracks

    CERN Document Server

    Kelley, Douglas H

    2010-01-01

    We present a method for reconstructing two-dimensional velocity fields at specified length scales using observational data from tracer particles in a flow, without the need for interpolation or smoothing. The algorithm, adapted from techniques proposed for oceanography, involves a least-squares projection of the measurements onto a set of two-dimensional, incompressible basis modes with known length scales. Those modes are constructed from components of the velocity potential function, which accounts for inflow and outflow at the open boundaries of the measurement region; and components of the streamfunction, which accounts for the remainder of the flow. All calculations are evaluated at particle locations, without interpolation onto an arbitrary grid. Since the modes have a well-defined length scales, scale-local flow properties are available directly. The technique eliminates outlier particles automatically and reduces the apparent compressibility of the data. Moreover the technique can be used to produce s...

  16. Production of microspheres for the computer automated radioactive particle tracking technique (CARPT)

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Wilson S., E-mail: wilson@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Pinto, Jose Carlos C.S., E-mail: pinto@peq.coppe.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Quimica; Nele, Marcio, E-mail: nele@eq.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Escola de Quimica

    2013-07-01

    The CARPT technique is a non-destructive test that uses a radiotracer in the form of a single particle to determine patterns of fluid displacement or to develop numerical models for multiphase dynamic systems. Through it, velocity profiles of fluids or even concentration profiles of a phase can be visualized and the diagnose of phenomena in industrial processes related to fluid dynamics can be performed (e.g. recirculations, eddies, segregation zones or diffusivities ). In this work, spherical shaped particles composed of polymethyl methacrylate (PMMA) and lanthanum oxide, about 0,2 mm in diameter, were obtained. They showed a satisfactory behavior in water after they had been dried for 24 h. In this manner, the synthesized spheres with a mean density of 1003,2 ± 0,1 kg/m{sup 3}, containing a lanthanum oxide fractional mass of about 5 %, are prompt to be tested as a new type of radioactive tracer particle. (author)

  17. Carrying Synchronous Voice Data On Asynchronous Networks

    Science.gov (United States)

    Bergman, Larry A.

    1990-01-01

    Buffers restore synchronism for internal use and permit asynchronism in external transmission. Proposed asynchronous local-area digital communication network (LAN) carries synchronous voice, data, or video signals, or non-real-time asynchronous data signals. Network uses double buffering scheme that reestablishes phase and frequency references at each node in network. Concept demonstrated in token-ring network operating at 80 Mb/s, pending development of equipment operating at planned data rate of 200 Mb/s. Technique generic and used with any LAN as long as protocol offers deterministic (or bonded) access delays and sufficient capacity.

  18. Asynchronous design of Networks-on-Chip

    DEFF Research Database (Denmark)

    Sparsø, Jens

    2007-01-01

    The Network-on-chip concept has evolved as a solution to a broad range of problems related to the design of complex systems-on-chip (SoC) with tenths or hundreds of (heterogeneous) IP-cores. The paper introduces the NoC concept, identifies a range of possible timing organizations (globally......-synchronous, mesochronous, globally-asynchronous locally-synchronous and fully asynchronous), discusses the circuitry needed to implement these timing methodologies, and provides some implementation details for a couple of asynchronous NoCs designed at the Technical University of Denmark (DTU). The paper is written...

  19. Burst-Mode Asynchronous Controllers on FPGA

    Directory of Open Access Journals (Sweden)

    Duarte L. Oliveira

    2008-01-01

    Full Text Available FPGAs have been mainly used to design synchronous circuits. Asynchronous design on FPGAs is difficult because the resulting circuit may suffer from hazard problems. We propose a method that implements a popular class of asynchronous circuits, known as burst mode, on FPGAs based on look-up table architectures. We present two conditions that, if satisfied, guarantee essential hazard-free implementation on any LUT-based FPGA. By doing that, besides all the intrinsic advantages of asynchronous over synchronous circuits, they also take advantage of the shorter design time and lower cost associated with FPGA designs.

  20. A Three-Dimensional Particle Tracking Velocimetry System for the Evaluation of Large Eddy Simulation Turbulence Models

    Science.gov (United States)

    Hunt, Joshua M.

    The necessity for evaluating the accuracy and characteristics of new Large-Eddy Simulation (LES) turbulence models in modern fluid mechanics research has inspired the development of a Three-Dimensional Particle Tracking Velocimetry (3DPTV) system capable of producing 3-Dimension 3-Component (3D3C) velocity vector fields. The system is based on the triangulation method of particle location and utilizes an optical system comprised of three 4008 x 2672 charge-coupled devices (CCDs), three 120mm lenses, and a water-filled prism. The tracer particles used in the system were Dynamic, Coherent Structures, and Stretched Vortex Models. The system is preferable to Direct Numerical Simulation (DNS) for such testing in that it is capable of acquiring data at a resolution adequate for a priori testing without the computational restrictions for high Reynolds numbers. In the present configuration, the system is capable of achieving a Taylor-microscale Reynolds number of 214, but with an increase to the CCD resolution of the system, a Taylor-microscale Reynolds number of nearly 400 would be attainable.

  1. Fluorescence labelling as tool for zeolite particle tracking in nanoremediation approaches.

    Science.gov (United States)

    Gillies, Glenn; Mackenzie, Katrin; Kopinke, Frank-Dieter; Georgi, Anett

    2016-04-15

    Colloidal Fe-zeolites such as Fe-BEA-35 are currently under study as new adsorbent and catalyst materials for in-situ chemical oxidation with H2O2. As for nanoremediation in general, the availability of suitable particle detection methods is a requirement for successful process development and particle tracing. Detection and distinguishing between natural colloids and introduced particles with a similar composition are a challenge. By means of fluorescence labelling, a highly specific detection option for Fe-BEA-35 was developed. 'Ship-in-a-bottle' synthesis of fluorescein within the zeolite pores, which was applied for the first time for a BEA type zeolite, provides a product with stable and non-extractable fluorescence. When the fluorescent labelled zeolite is added at a concentration of 1wt.% referring to the total zeolite mass, a very low detection limit of 1mg/L of total zeolite is obtained. Compared to commonly applied turbidity measurements, detection via fluorescence labelling is much more specific and sensitive. Fluorescence is only marginally affected by carboxymethyl cellulose, which is frequently applied as stabilizer in application suspensions but will be depleted upon contact with H2O2. Transport properties of fluorescent labelled and non-labelled Fe-zeolite particles are in agreement as determined in a column study with quartz sand and synthetic groundwater (classified as very hard). PMID:26849345

  2. Simulations of DSB Yields and Radiation-induced Chromosomal Aberrations in Human Cells Based on the Stochastic Track Structure iIduced by HZE Particles

    Science.gov (United States)

    Ponomarev, Artem; Plante, Ianik; George, Kerry; Wu, Honglu

    2014-01-01

    The formation of double-strand breaks (DSBs) and chromosomal aberrations (CAs) is of great importance in radiation research and, specifically, in space applications. We are presenting a new particle track and DNA damage model, in which the particle stochastic track structure is combined with the random walk (RW) structure of chromosomes in a cell nucleus. The motivation for this effort stems from the fact that the model with the RW chromosomes, NASARTI (NASA radiation track image) previously relied on amorphous track structure, while the stochastic track structure model RITRACKS (Relativistic Ion Tracks) was focused on more microscopic targets than the entire genome. We have combined chromosomes simulated by RWs with stochastic track structure, which uses nanoscopic dose calculations performed with the Monte-Carlo simulation by RITRACKS in a voxelized space. The new simulations produce the number of DSBs as function of dose and particle fluence for high-energy particles, including iron, carbon and protons, using voxels of 20 nm dimension. The combined model also calculates yields of radiation-induced CAs and unrejoined chromosome breaks in normal and repair deficient cells. The joined computational model is calibrated using the relative frequencies and distributions of chromosomal aberrations reported in the literature. The model considers fractionated deposition of energy to approximate dose rates of the space flight environment. The joined model also predicts of the yields and sizes of translocations, dicentrics, rings, and more complex-type aberrations formed in the G0/G1 cell cycle phase during the first cell division after irradiation. We found that the main advantage of the joined model is our ability to simulate small doses: 0.05-0.5 Gy. At such low doses, the stochastic track structure proved to be indispensable, as the action of individual delta-rays becomes more important.

  3. Simulations of DSB Yields and Radiation-induced Chromosomal Aberrations in Human Cells Based on the Stochastic Track Structure Induced by HZE Particles

    Science.gov (United States)

    Ponomarev, Artem; Plante, Ianik; George, Kerry; Wu, Honglu

    2014-01-01

    The formation of double-strand breaks (DSBs) and chromosomal aberrations (CAs) is of great importance in radiation research and, specifically, in space applications. We are presenting a new particle track and DNA damage model, in which the particle stochastic track structure is combined with the random walk (RW) structure of chromosomes in a cell nucleus. The motivation for this effort stems from the fact that the model with the RW chromosomes, NASARTI (NASA radiation track image) previously relied on amorphous track structure, while the stochastic track structure model RITRACKS (Relativistic Ion Tracks) was focused on more microscopic targets than the entire genome. We have combined chromosomes simulated by RWs with stochastic track structure, which uses nanoscopic dose calculations performed with the Monte-Carlo simulation by RITRACKS in a voxelized space. The new simulations produce the number of DSBs as function of dose and particle fluence for high-energy particles, including iron, carbon and protons, using voxels of 20 nm dimension. The combined model also calculates yields of radiation-induced CAs and unrejoined chromosome breaks in normal and repair deficient cells. The joined computational model is calibrated using the relative frequencies and distributions of chromosomal aberrations reported in the literature. The model considers fractionated deposition of energy to approximate dose rates of the space flight environment. The joined model also predicts of the yields and sizes of translocations, dicentrics, rings, and more complex-type aberrations formed in the G0/G1 cell cycle phase during the first cell division after irradiation. We found that the main advantage of the joined model is our ability to simulate small doses: 0.05-0.5 Gy. At such low doses, the stochastic track structure proved to be indispensable, as the action of individual delta-rays becomes more important.

  4. Effect Of The LEBT Solenoid Magnetic Field On The Beam Generation For Particle Tracking

    CERN Document Server

    Yarmohammadi Satri, M; CERN. Geneva. ATS Department

    2013-01-01

    Linac4 is a 160 MeV H- linear accelerator which will replace the 50 MeV proton Linac2 for upgrade of the LHC injectors with higher intensity and eventually an increase of the LHC luminosity. Linac4 structure is a source, a 45 keV low energy beam transport line (LEBT) with two solenoids, a 3 MeV Radiofrequency Quadrupole (RFQ), a Medium Energy Beam Transport line (MEBT), a 50 Mev DTL, a 100 Mev CCDTL and PIMS up to 160 Mev. We use Travel v4.07 and PathManager code for simulation. Firstly, we need to a file as a source and defining the beginning point (last point in tracking back) of simulation. We recognise the starting point base on the solenoid magnetic property of LEBT.

  5. Development of radiation hard semiconductor sensors for charged particle tracking at very high luminosities

    Science.gov (United States)

    Betancourt, Christopher; Fadeyev, Vitaliy; Sadrozinski, Hartmut F.; Wright, John

    2010-09-01

    The RD50 collaboration (sponsored by the European Organization for Nuclear Research CERN) has been exploring the development of radiation hard semiconductor devices for very high-luminosity colliders since 2002. The target fluence to qualify detectors set by the anticipated dose for the innermost tracking layers of the future upgrade of the CERN large hadron collider (LHC) is 1016 1 MeV neutron equivalent (neq) cm-2. This is much larger than typical fluences in space, but is mainly limited to displacement and total dose damage, without the single-event effects typical for the space environment. RD50 investigates radiation hardening from many angles, including: Search for alternative semiconductor to replace silicon, improvement of the intrinsic tolerance of the substrate material (p- vs. n-type, initial doping concentration, oxygen concentration), optimization of the readout geometry (collection of holes or electrons, surface treatment), novel detector designs (3D, edge-less, interconnects).

  6. Ionization Cluster Size Distributions Created by Low Energy Electrons and Alpha Particles in Nanometric Track Segment in Gases

    CERN Document Server

    Bantsar, Aliaksandr

    2012-01-01

    The interaction of ionizing radiation with nanometric targets is a field of interest for many branches of science such as: radiology, oncology, radiation protection and nanoelectronics. A new experimental technique known as nanodosimetry has been developed for the qualitative as well as quantitative description of these types of interactions. The work presented here is a contribution to this development, namely by further improvement of the new experimental technique called the Jet Counter, originally developed at the Andrzej So{\\l}tan Institute for Nuclear Studies. The Jet Counter is a unique device in the world for studying the interaction of low energy electrons with nanometer targets in the range 2-10 nm (in unit density). The basic experimental result is the frequency distribution of ionization cluster size produced by ionizing particles in a gaseous (nitrogen or propane) nanometric track segment. The first experimental data on the frequency distribution of ionization cluster size produced by low energy ...

  7. Fluidity evaluation of cell membrane model formed on graphene oxide with single particle tracking using quantum dot

    Science.gov (United States)

    Okamoto, Yoshiaki; Motegi, Toshinori; Iwasa, Seiji; Sandhu, Adarsh; Tero, Ryugo

    2015-04-01

    The lipid bilayer is the fundamental structure of plasma membranes, and artificial lipid bilayer membranes are used as model systems of cell membranes. Recently we reported the formation of a supported lipid bilayer (SLB) on graphene oxide (GO) by the vesicle fusion method. In this study, we conjugated a quantum dot (Qdot) on the SLB surface as a fluorescence probe brighter than dye-labeled lipid molecules, to qualitatively evaluate the fluidity of the SLB on GO by the single particle tracking method. We obtained the diffusion coefficient of the Qdot-conjugated lipids in the SLB on GO. We also performed the Qdot conjugation on the SLB containing a lipid conjugated with polyethylene glycol, to prevent the nonspecific adsorption of Qdots. The difference in the diffusion coefficients between the SLBs on the GO and the bare SiO2 regions was evaluated from the trajectory of single Qdot-conjugated lipid diffusing between the two regions.

  8. Energy deposition by a 106Ru/106Rh eye applicator simulated using LEPTS, a low-energy particle track simulation

    International Nuclear Information System (INIS)

    The present study introduces LEPTS, an event-by-event Monte Carlo programme, for simulating an ophthalmic 106Ru/106Rh applicator relevant in brachytherapy of ocular tumours. The distinctive characteristics of this code are the underlying radiation-matter interaction models that distinguish elastic and several kinds of inelastic collisions, as well as the use of mostly experimental input data. Special emphasis is placed on the treatment of low-energy electrons for generally being responsible for the deposition of a large portion of the total energy imparted to matter. - Highlights: → We present the Monte Carlo code LEPTS, a low-energy particle track simulation. → Carefully selected input data from 10 keV to 1 eV. → Application to an electron emitting Ru-106/Rh-106 plaque used in brachytherapy.

  9. FFT integration of instantaneous 3D pressure gradient fields measured by Lagrangian particle tracking in turbulent flows

    Science.gov (United States)

    Huhn, F.; Schanz, D.; Gesemann, S.; Schröder, A.

    2016-09-01

    Pressure gradient fields in unsteady flows can be estimated through flow measurements of the material acceleration in the fluid and the assumption of the governing momentum equation. In order to derive pressure from its gradient, almost exclusively two numerical methods have been used to spatially integrate the pressure gradient until now: first, direct path integration in the spatial domain, and second, the solution of the Poisson equation for pressure. Instead, we propose an alternative third method that integrates the pressure gradient field in Fourier space. Using a FFT function, the method is fast and easy to implement in programming languages for scientific computing. We demonstrate the accuracy of the integration scheme on a synthetic pressure field and apply it to an experimental example based on time-resolved material acceleration data from high-resolution Lagrangian particle tracking with the Shake-The-Box method.

  10. A new laser test stand for simulating charged-particle tracks

    Science.gov (United States)

    Unno, Y.; Iwata, Y.; Ohsugi, T.; Kohriki, T.; Kondo, T.; Terada, S.; Iwasaki, H.; Yamada, Y.

    1996-02-01

    We report on the construction of a new laser test stand equipped with a 1064 nm pulsed infrared YAG laser for simulating the passage of a charged particle in a silicon detector. The standard semiconductor repairing tool, the so-called laser-cutter, has been modified to have a newly developed optics which has the ability to reduce the light by the order of 10 6-10 8 and to adjust the spot size to several microns. As an application we measured the position dependence of the induced signals in a silicon-strip detector when the laser light hits in the region between the strips. The measurement has show that this device is very effective in evaluating the detailed response of a silicon detector without using charged particles generated by accelerators.

  11. ATLAS Transition Radiation Tracker (TRT): Straw Tubes for Tracking and Particle Identification at the Large Hadron Collider

    CERN Document Server

    Mindur, Bartosz; The ATLAS collaboration

    2016-01-01

    The ATLAS Transition Radiation Tracker (TRT) is the outermost of the three inner detector tracking subsystems and consists of $\\sim$300000 thin-walled drift tubes (``straw tubes'') that are 4~mm in diameter. The TRT system provides $\\sim$30 space points with $\\sim$130 micron resolution for charged tracks with $|\\eta| $ 0.5 GeV/c. The TRT also provides electron identification capability by detecting transition radiation (TR) X-ray photons in an Xe-based working gas mixture. Compared to Run 1, the LHC beams now provide a higher centre of mass energy (13 TeV), more bunches with a reduced spacing (25 ns), and more particles in each bunch leading to very challenging, higher occupancies in the TRT. Significant modifications of the TRT detector have been made for LHC Run 2 mainly to improve response to the expected much higher rate of hits and to mitigate leaks of the Xe-based active gas mixture. The higher rates required changes to the data acquisition system and introduction of validity gate to reject out-of-time ...

  12. ATLAS Transition Radiation Tracker (TRT): Straw Tubes for Tracking and Particle Identification at the Large Hadron Collider

    CERN Document Server

    Mindur, Bartosz; The ATLAS collaboration

    2016-01-01

    The ATLAS Transition Radiation Tracker (TRT) is the outermost of the three inner detector tracking subsystems and consists of 300000 thin-walled drift tubes (“straw tubes”) that are 4 mm in diameter. The TRT system provides 30 space points with 130 micron resolution for charged tracks with |η| 0.5 GeV/c. The TRT also provides electron identification capability by detecting transition radiation (TR) X-ray photons in a Xe-based working gas mixture. Compared to Run 1, the LHC beams now provide a higher center of mass energy (13 TeV), more bunches with a reduced spacing (25 ns), and more particles in each bunch leading to very challenging, higher occupancies in the TRT. We will present TRT modifications made for Run 2 for in areas: to improve response to the expected much higher rate of hits and to mitigate leaks of the Xe-based active gas mixture. The higher rates required changes to the data acquisition system and introduction of validity gate to reject out-of-time hits. Radiation-induced gain changes in ...

  13. Paramagnetic particles carried by cell-penetrating peptide tracking of bone marrow mesenchymal stem cells, a research in vitro

    International Nuclear Information System (INIS)

    The ability to track the distribution and differentiation of stem cells by high-resolution imaging techniques would have significant clinical and research implications. In this study, a model cell-penetrating peptide was used to carry gadolinium particles for magnetic resonance imaging of the mesenchymal stem cells. The mesenchymal stem cells were isolated from rat bone marrow by Percoll and identified by osteogenic differentiation in vitro. The cell-penetrating peptides labeled with fluorescein-5-isothiocyanate and gadolinium were synthesized by a solid-phase peptide synthesis method and the relaxivity of cell-penetrating peptide-gadolinium paramagnetic conjugate on 400 MHz nuclear magnetic resonance was 5.7311 ± 0.0122 mmol-1 s-1, higher than that of diethylenetriamine pentaacetic acid gadolinium (p < 0.05). Fluorescein imaging confirmed that this new peptide could internalize into the cytoplasm and nucleus. Gadolinium was efficiently internalized into mesenchymal stem cells by the peptide in a time- or concentration-dependent fashion, resulting in intercellular T1 relaxation enhancement, which was obviously detected by 1.5 T magnetic resonance imaging. Cytotoxicity assay and flow cytometric analysis showed the intercellular contrast medium incorporation did not affect cell viability and membrane potential gradient. The research in vitro suggests that the newly constructed peptides could be a vector for tracking mesenchymal stem cells

  14. New Software Techniques in Particle Physics and Improved Track Reconstruction for the CMS Experiment

    CERN Document Server

    Hauth, Thomas; Pfeiffer, Andreas

    This thesis presents improvements of the processing speed of HEP applications by making better use of the vector units in modern CPUs. To cope with the increased amount of LHC data, the parallel computing power of GPUs are one option. GPU-optimized reconstruction algorithms which provide a high level of parallelism are presented. Furthermore, the decay of neutral kaons was used to show the benefits of the Geant4-based fitting method when applied to the mass reconstruction of particles.

  15. A comparative validation of concepts for collision algorithms for stochastic particle tracking

    OpenAIRE

    Pischke, Philipp; Kneer, Reinhold; Schmidt, David P.

    2014-01-01

    Long-standing concerns about the accuracy of stochastic particle collision algorithms in Monte Carlo simulations have given rise to hybrid collision algorithms, which incorporate ideas from deterministic collision calculations in order to improve the realism of the collision calculation. Some hybrid collision algorithms have spread across commercial and research computational fluid dynamics codes without prior validation. The current work focuses on the predicted incidence of collision, using...

  16. The Use of Positron Emission Particle Tracking (PEPT) to Study the Movement of Inclusions in Low-Melting-Point Alloy Castings

    Science.gov (United States)

    Griffiths, W. D.; Beshay, Y.; Caden, A. J.; Fan, X.; Gargiuli, J.; Leadbeater, T. W.; Parker, D. J.

    2012-04-01

    Positron emission particle tracking (PEPT) employs a radioactive particle that decays by emission of positrons. These positrons collide with local electrons to produce γ-rays emitted at 180 deg to each other; detection of these γ-ray pairs allows the location of the radioactive particle to be identified within a few millimeters. This technique has been tested to determine its applicability to the study of inclusions in cast metals. To use particles representative of inclusion sizes in castings, both alumina particles and particles of an ion exchange resin were employed. These were within a size range of approximately 60 to 100 μm, made radioactive by adsorption and ion exchange techniques, respectively. The radioactive particles, of activity 100 to 1000 μCi, were introduced into tube-shaped castings made from the low-melting-point alloys Field's metal and Lensalloy-136, cast into an acrylic mold. The technique allowed the particle track to be determined from the point of initial introduction to the final resting place of the particle, with increasing reproducibility being obtained as the reproducibility as the casting technique was improved. Experiments in which filters were placed in to the running system showed that the removal of the particles by the filters varied according to the filter pore size.

  17. Twin screw wet granulation: the study of a continuous twin screw granulator using Positron Emission Particle Tracking (PEPT) technique.

    Science.gov (United States)

    Lee, Kai T; Ingram, Andy; Rowson, Neil A

    2012-08-01

    In this paper, Positron Emission Particle Tracking (PEPT) techniques are utilised to track the trajectory of single particles through the mixing and conveying zones of a Twin Screw Granulator (TSG). A TSG consisting of conveying zones and mixing zones is used in this study. The mixing zones are arranged with kneading discs at an angle of 30°, 60° or 90°. Experiments were carried out using different mixing configurations with various screw speed and total mass flow rate. The PEPT data obtained were then utilised to obtain the residence time distribution (RTD) and the Peclet number in an attempt to gain some insight into the mixing of the process. The fill level of the granulator was also estimated to study the mechanism of granulation. As might be expected, it was shown that the residence time of the granulation process increases with decreasing screw speed. It also increases with increasing angle of the arrangement of kneading blocks in the mixing zones, but will decreases when powder feed rate is increased. The fill level of the mixing zone in particular increases when the screw speed decreases or when powder feed rate increases. Furthermore, the fill level of the granulator will increase when the mixing zone configuration changes from 30° to 90°. It is shown that the granulator is never fully filled, even using 90° mixer elements implying limited compaction which may explain why the granules produced are porous compared with those from a high shear mixer. Interestingly, the RTD analysis reveals that the extent of axial mixing in the mixing zone of the granulator does not change significantly for different configurations and process conditions. There is evidence of a tail in the RTD which implies some material hold up and channelling. PMID:22561951

  18. Super-resolution imaging-based single particle tracking reveals dynamics of nanoparticle internalization by live cells

    Science.gov (United States)

    Li, Yiming; Shang, Li; Nienhaus, G. Ulrich

    2016-03-01

    By combining super-resolution photoactivation localization microscopy with single particle tracking, we have visualized the endocytic process in the live-cell environment with nanoparticles (NPs) of different size and surface functionalization. This allowed us to analyze the dynamics of NPs interacting with cells with high spatial and temporal resolution. We identified two distinctly different types of pathways by which NPs are internalized via clathrin-coated pits (CCPs). Predominantly, NPs first bind to the membrane and, subsequently, CCPs form at this site. However, there are also instances where a NP diffuses on the membrane and utilizes a preformed CCP. Moreover, we have applied this new method to further explore the effects of size and surface functionalization on the NP dynamics on the plasma membrane and the ensuing endocytosis.By combining super-resolution photoactivation localization microscopy with single particle tracking, we have visualized the endocytic process in the live-cell environment with nanoparticles (NPs) of different size and surface functionalization. This allowed us to analyze the dynamics of NPs interacting with cells with high spatial and temporal resolution. We identified two distinctly different types of pathways by which NPs are internalized via clathrin-coated pits (CCPs). Predominantly, NPs first bind to the membrane and, subsequently, CCPs form at this site. However, there are also instances where a NP diffuses on the membrane and utilizes a preformed CCP. Moreover, we have applied this new method to further explore the effects of size and surface functionalization on the NP dynamics on the plasma membrane and the ensuing endocytosis. Electronic supplementary information (ESI) available: Experimental section, supporting figures and videos. See DOI: 10.1039/c6nr01495j

  19. Experimental and Particle-Tracking Model Analysis of Anomalous Transport and Sorption of Nickel in Natural Soil Columns

    Science.gov (United States)

    Edery, Y.; Rubin, S.; Dror, I.; Berkowitz, B.

    2012-12-01

    Nickel migration measured in laboratory-scale, natural soil column experiments is shown to display anomalous (non-Fickian) transport and non-equilibrium adsorption and desorption patterns. Similar experiments using a conservative tracer also exhibit anomalous behavior. In parallel batch experiments, adsorption and desorption isotherms demonstrate hysteresis, indicating some permanent adsorption. While adsorption is described by the Langmuir isotherm, equilibrium concentrations are higher than those predicted by the same model for desorption. Furthermore, batch and flow-through column experiments show the occurrence of ion exchange of nickel with magnesium and potassium in the soil; aluminum and other ion concentrations are also affected by the presence of nickel. Strong retention of nickel during transport in soil columns leads to delayed initial breakthrough (~40 pore volumes), slow increase in concentration, and extended concentration tailing at long times. Standard models, including two-site non-equilibrium formulations, fail to capture these features quantitatively. We describe the mechanisms of transport and adsorption/desorption in terms of a continuous time random walk (CTRW) model, and use a particle tracking formulation to simulate the nickel migration in the column. This approach allows us to capture the non-Fickian transport and the subtle local effects of adsorption and desorption. The model uses transport parameters estimated from the conservative tracer and, as a starting point, adsorption/desorption parameters based on the batch experiments to account for the reactions. It is shown that the batch parameters under-estimate the actual adsorption in the column. The CTRW particle tracking model is shown to capture both the full evolution of the measured breakthrough curve and the measured spatial concentration profile. Analysis of these results provides further understanding of the interaction and dynamics between transport and sorption mechanisms in

  20. Implementing LOTOS as asynchronously Communicating Processes

    OpenAIRE

    Sjödin, Peter

    1990-01-01

    A technique is presented for translating LOTOS specifications into implementations executing as asynchronously communicating processes. This generation of implementations is described as transformations of LOTOS expressions. A protocol for implementing LOTOS synchronisation is described.

  1. Asynchronous Data Fusion With Parallel Filtering Frame

    OpenAIRE

    Na Li; Junhui Liu

    2011-01-01

    This paper studies the design of data fusion algorithm for asynchronous system with integer times sampling. Firstly, the multisensor asynchronous samplings is mapped to the basic axis, accordingly a sampling sequence of single sensor can be taken. Secondly, aiming at the sensor with the densest sampling points, the modified parallel filtering is given. Afterwards, the sequential filtering fusion method is introduced to deal with the case that there are multiple mapped measurements at some sam...

  2. REACTIVE POWER COMPENSATION IN ASYNCHRONOUS ELECTRIC DRIVES

    Directory of Open Access Journals (Sweden)

    V.S. Malyar

    2013-10-01

    Full Text Available A problem of calculating capacity of cosine capacitors for individual compensation of reactive power in asynchronous electric drives in stationary and transient operation modes is considered. The algorithm introduced employs a high-adequacy mathematical model of asynchronous motor developed on the theory of representing vectors which takes into account both the magnetic core saturation and the current displacement in the rotor bars.

  3. Asynchronous communication in real space process algebra

    OpenAIRE

    Baeten, JCM Jos; Bergstra, JA Jan

    1992-01-01

    A version of classical real space process algebra is given in which messages travel with constant speed through a three-dimensional medium. It follows that communication is asynchronous and has a broadcasting character. A state operator is used to describe asynchronous message transfer and a priority mechanism allows to express the broadcasting mechanism. As an application, a protocol is specified in which the receiver moves with respect to the sender.

  4. Performance Analysis of Asynchronous Multicarrier Wireless Networks

    OpenAIRE

    Lin, Xingqin; Jiang, Libin; Andrews, Jeffrey G.

    2014-01-01

    This paper develops a novel analytical framework for asynchronous wireless networks deploying multicarrier transmission. Nodes in the network have different notions of timing, so from the viewpoint of a typical receiver, the received signals from different transmitters are asynchronous, leading to a loss of orthogonality between subcarriers. We first develop a detailed link-level analysis based on OFDM, based on which we propose a tractable system-level signal-to-interference-plus-noise ratio...

  5. An Adaptive Particle Filtering Approach to Tracking Modes in a Varying Shallow Ocean Environment

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J V

    2011-03-22

    The shallow ocean environment is ever changing mostly due to temperature variations in its upper layers (< 100m) directly affecting sound propagation throughout. The need to develop processors that are capable of tracking these changes implies a stochastic as well as an 'adaptive' design. The stochastic requirement follows directly from the multitude of variations created by uncertain parameters and noise. Some work has been accomplished in this area, but the stochastic nature was constrained to Gaussian uncertainties. It has been clear for a long time that this constraint was not particularly realistic leading a Bayesian approach that enables the representation of any uncertainty distribution. Sequential Bayesian techniques enable a class of processors capable of performing in an uncertain, nonstationary (varying statistics), non-Gaussian, variable shallow ocean. In this paper adaptive processors providing enhanced signals for acoustic hydrophonemeasurements on a vertical array as well as enhanced modal function estimates are developed. Synthetic data is provided to demonstrate that this approach is viable.

  6. Two particle tracking and detection in a single Gaussian beam optical trap.

    Science.gov (United States)

    Praveen, P; Yogesha; Iyengar, Shruthi S; Bhattacharya, Sarbari; Ananthamurthy, Sharath

    2016-01-20

    We have studied in detail the situation wherein two microbeads are trapped axially in a single-beam Gaussian intensity profile optical trap. We find that the corner frequency extracted from a power spectral density analysis of intensity fluctuations recorded on a quadrant photodetector (QPD) is dependent on the detection scheme. Using forward- and backscattering detection schemes with single and two laser wavelengths along with computer simulations, we conclude that fluctuations detected in backscattering bear true position information of the bead encountered first in the beam propagation direction. Forward scattering, on the other hand, carries position information of both beads with substantial contribution from the bead encountered first along the beam propagation direction. Mie scattering analysis further reveals that the interference term from the scattering of the two beads contributes significantly to the signal, precluding the ability to resolve the positions of the individual beads in forward scattering. In QPD-based detection schemes, detection through backscattering, thereby, is imperative to track the true displacements of axially trapped microbeads for possible studies on light-mediated interbead interactions. PMID:26835934

  7. Two particle tracking and detection in a single Gaussian beam optical trap.

    Science.gov (United States)

    Praveen, P; Yogesha; Iyengar, Shruthi S; Bhattacharya, Sarbari; Ananthamurthy, Sharath

    2016-01-20

    We have studied in detail the situation wherein two microbeads are trapped axially in a single-beam Gaussian intensity profile optical trap. We find that the corner frequency extracted from a power spectral density analysis of intensity fluctuations recorded on a quadrant photodetector (QPD) is dependent on the detection scheme. Using forward- and backscattering detection schemes with single and two laser wavelengths along with computer simulations, we conclude that fluctuations detected in backscattering bear true position information of the bead encountered first in the beam propagation direction. Forward scattering, on the other hand, carries position information of both beads with substantial contribution from the bead encountered first along the beam propagation direction. Mie scattering analysis further reveals that the interference term from the scattering of the two beads contributes significantly to the signal, precluding the ability to resolve the positions of the individual beads in forward scattering. In QPD-based detection schemes, detection through backscattering, thereby, is imperative to track the true displacements of axially trapped microbeads for possible studies on light-mediated interbead interactions.

  8. A Monte Carlo Study of the Momentum Dependence on the Results of Tracking Unknown Particle Species in the BaBar Detector

    Energy Technology Data Exchange (ETDEWEB)

    Sewerynek, Stephen; /British Columbia U.

    2007-04-06

    The BABAR experiment is composed of an international collaboration that will test the Standard Model prediction of CP violation. To accomplish this a new detector was constructed at the asymmetric B Factory, located at the Stanford Linear Accelerator Center. The tests will shed some light on the origins of CP violation, which is an important aspect in explaining the matter/antimatter asymmetry in the universe. In particular, the BABAR experiment will measure CP violation in the neutral B meson system. In order to succeed, the BABAR experiment requires excellent track fitting and particle species identification. Prior to the current study, track fitting was done using only one particle species--the pion. But given the momentum dependence on the accuracy of the results from this choice of particle species, a better algorithm needed to be developed. Monte Carlo simulations were carried out and a new algorithm utilizing all five particle species present in the BABAR detector was created.

  9. Microdosimetric spectra and LET distributions on board the Mir station obtained with a particle track detector

    International Nuclear Information System (INIS)

    A spectrometer measuring energy lost (?E) was used to determine linear energy transfer (LET) spectra on board the Mir orbital station during the period from 8 October 1997 to 16 June 2000, i.e. during the 24th, 26th, 27th and 28th basic expeditions. It was found that the LET spectra of secondary particles between 10 and 700 keV.μm-1 in tissue do not depend on the external radiator, with the average quality factors for the region mentioned being about 6.4 with ICRP 26 quality factors or about 7.4 with ICRP 60 quality factors. Both differential and integral LET spectra are presented for some typical cases. The spectra permitted us to calculate the total doses and dose equivalents due to particles with the LET values in the mentioned region. It was found that these doses are higher when the detector was placed in a less shielded area. It was also found that these doses vary from one expedition to another. The correlation of these variations with the solar activity level was studied. (author)

  10. A Chaos-Enhanced Particle Swarm Optimization with Adaptive Parameters and Its Application in Maximum Power Point Tracking

    Directory of Open Access Journals (Sweden)

    Ying-Yi Hong

    2016-01-01

    Full Text Available This work proposes an enhanced particle swarm optimization scheme that improves upon the performance of the standard particle swarm optimization algorithm. The proposed algorithm is based on chaos search to solve the problems of stagnation, which is the problem of being trapped in a local optimum and with the risk of premature convergence. Type 1′′ constriction is incorporated to help strengthen the stability and quality of convergence, and adaptive learning coefficients are utilized to intensify the exploitation and exploration search characteristics of the algorithm. Several well known benchmark functions are operated to verify the effectiveness of the proposed method. The test performance of the proposed method is compared with those of other popular population-based algorithms in the literature. Simulation results clearly demonstrate that the proposed method exhibits faster convergence, escapes local minima, and avoids premature convergence and stagnation in a high-dimensional problem space. The validity of the proposed PSO algorithm is demonstrated using a fuzzy logic-based maximum power point tracking control model for a standalone solar photovoltaic system.

  11. Confined Diffusion Without Fences of a G-Protein-Coupled Receptor as Revealed by Single Particle Tracking

    Science.gov (United States)

    Daumas, Frédéric; Destainville, Nicolas; Millot, Claire; Lopez, André; Dean, David; Salomé, Laurence

    2003-01-01

    Single particle tracking is a powerful tool for probing the organization and dynamics of the plasma membrane constituents. We used this technique to study the μ-opioid receptor belonging to the large family of the G-protein-coupled receptors involved with other partners in a signal transduction pathway. The specific labeling of the receptor coupled to a T7-tag at its N-terminus, stably expressed in fibroblastic cells, was achieved by colloidal gold coupled to a monoclonal anti T7-tag antibody. The lateral movements of the particles were followed by nanovideomicroscopy at 40 ms time resolution during 2 min with a spatial precision of 15 nm. The receptors were found to have either a slow or directed diffusion mode (10%) or a walking confined diffusion mode (90%) composed of a long-term random diffusion and a short-term confined diffusion, and corresponding to a diffusion confined within a domain that itself diffuses. The results indicate that the confinement is due to an effective harmonic potential generated by long-range attraction between the membrane proteins. A simple model for interacting membrane proteins diffusion is proposed that explains the variations with the domain size of the short-term and long-term diffusion coefficients. PMID:12524289

  12. Calculation of RBE for normal tissue complications based on charged particle track structure

    International Nuclear Information System (INIS)

    A new approach for the calculation of RBE for normal tissue complications after charged particle and neutron irradiation is discussed. It is based on the extension of a model originally developed for the application to cell survival. It can be shown, that according to the model RBE values are determined largely by the α/β-ratio of the photon dose response curve, but are expected to be nearly independent of the absolute values of α and β. Thus, the model can be applied to normal tissue complications as well, where α/β-ratios can be determined by means of fractionation experiments. Agreement of model predictions and experimental results obtained in animal experiments confirm the appliability of the model even in the case of complex biological endpoints. (orig.)

  13. TRACKING AND MONITORING OF TAGGED OBJECTS EMPLOYING PARTICLE SWARM OPTIMIZATION ALGORITHM IN A DEPARTMENTAL STORE

    Directory of Open Access Journals (Sweden)

    Indrajit Bhattacharya

    2011-05-01

    Full Text Available The present paper proposes a departmental store automation system based on Radio Frequency Identification (RFID technology and Particle Swarm Optimization (PSO algorithm. The items in the departmental store spanned over different sections and in multiple floors, are tagged with passive RFID tags. The floor is divided into number of zones depending on different types of items that are placed in their respective racks. Each of the zones is placed with one RFID reader, which constantly monitors the items in their zone and periodically sends that information to the application. The problem of systematic periodic monitoring of the store is addressed in this application so that the locations, distributions and demands of every item in the store can be invigilated with intelligence. The proposed application is successfully demonstrated on a simulated case study.

  14. Comparison of bulk and epitaxial 4H-SiC detectors for radiation hard particle tracking

    CERN Document Server

    Quinn, T; Bruzzi, M; Cunningham, W; Mathieson, K; Moll, M; Nelson, T; Nilsson, H E; Pintillie, I; Rahman, M; Reynolds, L; Sciortino, S; Sellin, P J; Strachan, H; Svensson, B G; Vaitkus, J

    2003-01-01

    Measurements and simulations have been carried out using bulk and epitaxial SiC detectors. Samples were irradiated to fluences of around 10**1**4 hardrons/cm**2. Material of thickness 40um gave a charge collection efficiency of 100% dropping to around 60% at 100mum thickness. Detailed MEDICI simulations incorporated the main defect levels in SiC, the vanadium center, Z-center and a mid-gap level as measured by deep level transient spectroscopy and other techniques. Calculated recombination currents and charge collection efficiencies at varying fluences were comparable to experimental data. The study suggests that SiC detectors will operate up to fluences around 10 **1**6/cm**2 as required by future particle physics experiments.

  15. Study of latent and etched tracks by a charged particle transmission technique

    Energy Technology Data Exchange (ETDEWEB)

    Vacik, J.; Cervena, J.; Hnatowicz, V.; Fink, D.; Kobayashi, Y.; Hirata, K.; Apel, P.Yu.; Strauss, P

    1999-06-01

    A recently suggested technique for non-destructive investigation of inhomogeneities in thin objects, which is based on the measurement of the energy spectra of charged particles transmitted through the object, is used for the study of thermal annealing of 10-20 {mu}m thick polyethylene terephtalate, polypropylene and polycarbonate foils irradiated with 1-10 MeV/amu heavy ions. At elevated temperature a foil linear contraction is observed on pristine and irradiated material. Also the foil roughness increases with increasing temperature. On the same foils with etched pores 0.5-1.0 {mu}m in diameter, the thermal annealing results in gradual closing of the pores up to about 30% of their initial diameter at the temperatures of 150-175 deg. C. At higher temperatures the pore diameter increases and achieves its initial value.

  16. Study of latent and etched tracks by a charged particle transmission technique

    CERN Document Server

    Vacik, J; Hnatowicz, V; Fink, D; Kobayashi, Y; Hirata, K; Apel, P Y; Strauss, P

    1999-01-01

    A recently suggested technique for non-destructive investigation of inhomogeneities in thin objects, which is based on the measurement of the energy spectra of charged particles transmitted through the object, is used for the study of thermal annealing of 10-20 mu m thick polyethylene terephtalate, polypropylene and polycarbonate foils irradiated with 1-10 MeV/amu heavy ions. At elevated temperature a foil linear contraction is observed on pristine and irradiated material. Also the foil roughness increases with increasing temperature. On the same foils with etched pores 0.5-1.0 mu m in diameter, the thermal annealing results in gradual closing of the pores up to about 30% of their initial diameter at the temperatures of 150-175 deg. C. At higher temperatures the pore diameter increases and achieves its initial value.

  17. Combination of Annealing Particle Filter and Belief Propagation for 3D Upper Body Tracking

    Directory of Open Access Journals (Sweden)

    Ilaria Renna

    2012-01-01

    Full Text Available 3D upper body pose estimation is a topic greatly studied by the computer vision society because it is useful in a great number of applications, mainly for human robots interactions including communications with companion robots. However there is a challenging problem: the complexity of classical algorithms that increases exponentially with the dimension of the vectors’ state becomes too difficult to handle. To tackle this problem, we propose a new approach that combines several annealing particle filters defined independently for each limb and belief propagation method to add geometrical constraints between individual filters. Experimental results on a real human gestures sequence will show that this combined approach leads to reliable results.

  18. Radial basis function interpolation of unstructured, three-dimensional, volumetric particle tracking velocimetry data

    International Nuclear Information System (INIS)

    Unstructured three-dimensional fluid velocity data were interpolated using Gaussian radial basis function (RBF) interpolation. Data were generated to imitate the spatial resolution and experimental uncertainty of a typical implementation of defocusing digital particle image velocimetry. The velocity field associated with a steadily rotating infinite plate was simulated to provide a bounded, fully three-dimensional analytical solution of the Navier–Stokes equations, allowing for robust analysis of the interpolation accuracy. The spatial resolution of the data (i.e. particle density) and the number of RBFs were varied in order to assess the requirements for accurate interpolation. Interpolation constraints, including boundary conditions and continuity, were included in the error metric used for the least-squares minimization that determines the interpolation parameters to explore methods for improving RBF interpolation results. Even spacing and logarithmic spacing of RBF locations were also investigated. Interpolation accuracy was assessed using the velocity field, divergence of the velocity field, and viscous torque on the rotating boundary. The results suggest that for the present implementation, RBF spacing of 0.28 times the boundary layer thickness is sufficient for accurate interpolation, though theoretical error analysis suggests that improved RBF positioning may yield more accurate results. All RBF interpolation results were compared to standard Gaussian weighting and Taylor expansion interpolation methods. Results showed that RBF interpolation improves interpolation results compared to the Taylor expansion method by 60% to 90% based on the average squared velocity error and provides comparable velocity results to Gaussian weighted interpolation in terms of velocity error. RMS accuracy of the flow field divergence was one to two orders of magnitude better for the RBF interpolation compared to the other two methods. RBF interpolation that was applied to

  19. Asynchronous Task-Based Polar Decomposition on Manycore Architectures

    KAUST Repository

    Sukkari, Dalal

    2016-10-25

    This paper introduces the first asynchronous, task-based implementation of the polar decomposition on manycore architectures. Based on a new formulation of the iterative QR dynamically-weighted Halley algorithm (QDWH) for the calculation of the polar decomposition, the proposed implementation replaces the original and hostile LU factorization for the condition number estimator by the more adequate QR factorization to enable software portability across various architectures. Relying on fine-grained computations, the novel task-based implementation is also capable of taking advantage of the identity structure of the matrix involved during the QDWH iterations, which decreases the overall algorithmic complexity. Furthermore, the artifactual synchronization points have been severely weakened compared to previous implementations, unveiling look-ahead opportunities for better hardware occupancy. The overall QDWH-based polar decomposition can then be represented as a directed acyclic graph (DAG), where nodes represent computational tasks and edges define the inter-task data dependencies. The StarPU dynamic runtime system is employed to traverse the DAG, to track the various data dependencies and to asynchronously schedule the computational tasks on the underlying hardware resources, resulting in an out-of-order task scheduling. Benchmarking experiments show significant improvements against existing state-of-the-art high performance implementations (i.e., Intel MKL and Elemental) for the polar decomposition on latest shared-memory vendors\\' systems (i.e., Intel Haswell/Broadwell/Knights Landing, NVIDIA K80/P100 GPUs and IBM Power8), while maintaining high numerical accuracy.

  20. Asynchronous Complex Pipeline Design Based on ARM Instruction Set

    Institute of Scientific and Technical Information of China (English)

    WANG Bing; WANG Qin; PENG Rui-hua; FU Yu-zhuo

    2008-01-01

    This paper proposes an asynchronous complex pipeline based on ARM-V3 instruction set. Muller pipeline structure is used as prototype, and the factors which may affect pipeline performance are analyzed. To balance the difficulty of asynchronous design and performance analysis, both complete asynchronous and partial asynchronous structures aere designed and compared. Results of comparison with the well-Rnown industrial product ARM922T verify that about 30% and 40% performance improvement of the partial and complete asynchronous complex pipelines can be obtained respectively. The design methodologies can also be used in the design of other asynchronous pipelines.

  1. 3D Particle Track Reconstrution in a Single Layer Cadmium-Telluride Hybrid Active Pixel Detector

    CERN Document Server

    Filipenko, Mykhaylo; Anton, Gisela; Michel, Thilo

    2014-01-01

    In the past 20 years the search for neutrinoless double beta decay has driven many developements in all kind of detector technology. A new branch in this field are highly-pixelated semiconductor detectors - such as the CdTe-Timepix detectors. It compromises a cadmium-telluride sensor of 14 mm x 14 mm x 1 mm size with an ASIC which has 256 x 256 pixel of 55 \\textmu m pixel pitch and can be used to obtain either spectroscopic or timing information in every pixel. In regular operation it can provide a 2D projection of particle trajectories; however, three dimensional trajectories are desirable for neutrinoless double beta decay and other applications. In this paper we present a method to obtain such trajectories. The method was developed and tested with simulations that assume some minor modifications to the Timepix ASIC. Also, we were able to test the method experimentally and in the best case achieved a position resolution of about 90 \\textmu m with electrons of 4.4 GeV.

  2. Quantification of the secondary flow in a radial coupled centrifugal blood pump based on particle tracking velocimetry.

    Science.gov (United States)

    Watanabe, Nobuo; Masuda, Takaya; Iida, Tomoya; Kataoka, Hiroyuki; Fujimoto, Tetsuo; Takatani, Setsuo

    2005-01-01

    Secondary flow in the centrifugal blood pump helps to enhance the washout effect and to minimize thrombus formation. On the other hand, it has an adverse effect on pump efficiency. Excessive secondary flow may induce hemolytic effects. Understanding the secondary flow is thus important to the design of a compact, efficient, biocompatible blood pump. This study examined the secondary flow in a radial coupled centrifugal blood pump based on a simple particle tracking velocimetry (PTV) technique. A radial magnetically coupled centrifugal blood pump has a bell-shaped narrow clearance between the impeller inner radius and the pump casing. In order to vary the flow levels through the clearance area, clearance widths of 0.25 mm and 0.50 mm and impeller washout holes with diameters of 0 mm, 2.5 mm, and 4 mm were prepared. A high-speed video camera (2000 frames per second) was used to capture the particle images from which radial flow components were derived. The flow in the space behind the impeller was assumed to be laminar and Couette type. The larger the inner clearance or diameter of washout hole, the greater was the secondary flow rate. Without washout holes, the flow behind the impeller resulted in convection. The radial flow through the washout holes of the impeller was conserved in the radial as well as in the axial direction behind the impeller. The increase in the secondary flow reduced the net pump efficiency. Simple PTV was successful in quantifying the flow in the space behind the impeller. The results verified the hypothesis that the flow behind the impeller was theoretically Couette along the circumferential direction. The convection flow observed behind the impeller agreed with the reports of other researchers. Simple PTV was effective in understanding the fluid dynamics to help improve the compact, efficient, and biocompatible centrifugal blood pump for safe clinical applications.

  3. Normalized and Asynchronous Mirror Alignment for Cherenkov Telescopes

    CERN Document Server

    Ahnen, M L; Balbo, M; Bergmann, M; Biland, A; Blank, M; Bretz, T; Bruegge, K A; Buss, J; Domke, M; Dorner, D; Einecke, S; Hempfling, C; Hildebrand, D; Hughes, G; Lustermann, W; Mannheim, K; Mueller, S A; Neise, D; Neronov, A; Noethe, M; Overkemping, A -K; Paravac, A; Pauss, F; Rhode, W; Shukla, A; Temme, F; Thaele, J; Toscano, S; Vogler, P; Walter, R; Wilbert, A

    2016-01-01

    Imaging Atmospheric Cherenkov Telescopes (IACTs) need imaging optics with large apertures and high image intensities to map the faint Cherenkov light emitted from cosmic ray air showers onto their image sensors. Segmented reflectors fulfill these needs, and as they are composed from mass production mirror facets they are inexpensive and lightweight. However, as the overall image is a superposition of the individual facet images, alignment is a challenge. Here we present a computer vision based star tracking alignment method, which also works for limited or changing star light visibility. Our method normalizes the mirror facet reflection intensities to become independent of the reference star's intensity or the cloud coverage. Using two CCD cameras, our method records the mirror facet orientations asynchronously of the telescope drive system, and thus makes the method easy to integrate into existing telescopes. It can be combined with remote facet actuation, but does not require one to work. Furthermore, it ca...

  4. A New Numerical Approach to Evaluate Variation of Electric Field Strength at the End of Particle Trajectory in Nuclear Track Detectors

    Institute of Scientific and Technical Information of China (English)

    SUN Xiu-Dong; Ali Mostofizadeh; HOU Chun-Feng; M.Reza Kardan

    2008-01-01

    A geometrical model for an electrochemical etching(ECE)track in a dielectric detector is defined and a primary programme is written to generate the track.The generated track is transformed to an M×N matrix of primary voltages.Using a numerical method,the matrix of final voltages is computed,and using another numerical approach.the electric field strengths in the elements of detector volume are computed.The final field strength at the end of particle trajectory is obtained.The results of our numerical computation show that there are exact correlations between the field strength at the end of particle trajectory and the parameters of track under ECE.It is found that although two traditional models of Mason and Smythe in dielectrics can be partly applied for short we find that there is an expressive relationship between the field strength and the incidence angle of impacted particle.while the mentioned traditional models are not able to explain this effect.

  5. Nanoscopic substructures of raft-mimetic liquid-ordered membrane domains revealed by high-speed single-particle tracking.

    Science.gov (United States)

    Wu, Hsiao-Mei; Lin, Ying-Hsiu; Yen, Tzu-Chi; Hsieh, Chia-Lung

    2016-01-01

    Lipid rafts are membrane nanodomains that facilitate important cell functions. Despite recent advances in identifying the biological significance of rafts, nature and regulation mechanism of rafts are largely unknown due to the difficulty of resolving dynamic molecular interaction of rafts at the nanoscale. Here, we investigate organization and single-molecule dynamics of rafts by monitoring lateral diffusion of single molecules in raft-containing reconstituted membranes supported on mica substrates. Using high-speed interferometric scattering (iSCAT) optical microscopy and small gold nanoparticles as labels, motion of single lipids is recorded via single-particle tracking (SPT) with nanometer spatial precision and microsecond temporal resolution. Processes of single molecules partitioning into and escaping from the raft-mimetic liquid-ordered (Lo) domains are directly visualized in a continuous manner with unprecedented clarity. Importantly, we observe subdiffusion of saturated lipids in the Lo domain in microsecond timescale, indicating the nanoscopic heterogeneous molecular arrangement of the Lo domain. Further analysis of the diffusion trajectory shows the presence of nano-subdomains of the Lo phase, as small as 10 nm, which transiently trap the lipids. Our results provide the first experimental evidence of non-uniform molecular organization of the Lo phase, giving a new view of how rafts recruit and confine molecules in cell membranes. PMID:26861908

  6. Nanoscopic substructures of raft-mimetic liquid-ordered membrane domains revealed by high-speed single-particle tracking

    Science.gov (United States)

    Wu, Hsiao-Mei; Lin, Ying-Hsiu; Yen, Tzu-Chi; Hsieh, Chia-Lung

    2016-02-01

    Lipid rafts are membrane nanodomains that facilitate important cell functions. Despite recent advances in identifying the biological significance of rafts, nature and regulation mechanism of rafts are largely unknown due to the difficulty of resolving dynamic molecular interaction of rafts at the nanoscale. Here, we investigate organization and single-molecule dynamics of rafts by monitoring lateral diffusion of single molecules in raft-containing reconstituted membranes supported on mica substrates. Using high-speed interferometric scattering (iSCAT) optical microscopy and small gold nanoparticles as labels, motion of single lipids is recorded via single-particle tracking (SPT) with nanometer spatial precision and microsecond temporal resolution. Processes of single molecules partitioning into and escaping from the raft-mimetic liquid-ordered (Lo) domains are directly visualized in a continuous manner with unprecedented clarity. Importantly, we observe subdiffusion of saturated lipids in the Lo domain in microsecond timescale, indicating the nanoscopic heterogeneous molecular arrangement of the Lo domain. Further analysis of the diffusion trajectory shows the presence of nano-subdomains of the Lo phase, as small as 10 nm, which transiently trap the lipids. Our results provide the first experimental evidence of non-uniform molecular organization of the Lo phase, giving a new view of how rafts recruit and confine molecules in cell membranes.

  7. LIQUID PHASE FLOW ESTIMATION IN GAS-LIQUID TWO-PHASE FLOW USING INVERSE ANALYSIS AND PARTICLE TRACKING VELOCIMETRY

    Institute of Scientific and Technical Information of China (English)

    CHENG Wen; MURAI Yuichi; SASAKI Toshio; YAMAMOTO Fujio

    2004-01-01

    An inverse analysis algorithm is proposed for estimating liquid phase flow field from measurement data of bubble motion. This kind of technology will be applied in future for various estimation of fluid flow in rivers, lakes, sea surface flow, and also microscopic channel flow as the problem-handling in civil, mechanical, electronic, and chemical engineering. The relationship between the dispersion motion and the carrier phase flow is governed and expressed by the translational motion equation of spherical dispersion. The equation consists of all the force components including inertia, added inertia, drag, lift, pressure gradient force and gravity force. Using this equation enables us to estimate the carrier phase flow structure using only the data of the dispersion motion. Whole field liquid flow structure is also estimated using spatial or temporal interpolation method. In order to verify this principle, the Taylor-Green vortex flow, and the Karman vortex shedding from a square cylinder have been chosen. The results show that the combination of the inverse analysis and Particle Tracking Velocimetry (PTV) with the spatio-temporal post-processing algorithm could reconstruct well the carrier phase flow of the gas-liquid two-phase flow.

  8. Nanoscopic substructures of raft-mimetic liquid-ordered membrane domains revealed by high-speed single-particle tracking.

    Science.gov (United States)

    Wu, Hsiao-Mei; Lin, Ying-Hsiu; Yen, Tzu-Chi; Hsieh, Chia-Lung

    2016-01-01

    Lipid rafts are membrane nanodomains that facilitate important cell functions. Despite recent advances in identifying the biological significance of rafts, nature and regulation mechanism of rafts are largely unknown due to the difficulty of resolving dynamic molecular interaction of rafts at the nanoscale. Here, we investigate organization and single-molecule dynamics of rafts by monitoring lateral diffusion of single molecules in raft-containing reconstituted membranes supported on mica substrates. Using high-speed interferometric scattering (iSCAT) optical microscopy and small gold nanoparticles as labels, motion of single lipids is recorded via single-particle tracking (SPT) with nanometer spatial precision and microsecond temporal resolution. Processes of single molecules partitioning into and escaping from the raft-mimetic liquid-ordered (Lo) domains are directly visualized in a continuous manner with unprecedented clarity. Importantly, we observe subdiffusion of saturated lipids in the Lo domain in microsecond timescale, indicating the nanoscopic heterogeneous molecular arrangement of the Lo domain. Further analysis of the diffusion trajectory shows the presence of nano-subdomains of the Lo phase, as small as 10 nm, which transiently trap the lipids. Our results provide the first experimental evidence of non-uniform molecular organization of the Lo phase, giving a new view of how rafts recruit and confine molecules in cell membranes.

  9. Single Particle Tracking reveals two distinct environments for CD4 receptors at the surface of living T lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Mascalchi, Patrice; Lamort, Anne Sophie; Salome, Laurence [CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne, BP 64182, F-31077 Toulouse (France); Universite de Toulouse, UPS, IPBS (Institut de Pharmacologie et de Biologie Structurale), F-31077 Toulouse (France); Dumas, Fabrice, E-mail: fabrice.dumas@ipbs.fr [CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne, BP 64182, F-31077 Toulouse (France); Universite de Toulouse, UPS, IPBS (Institut de Pharmacologie et de Biologie Structurale), F-31077 Toulouse (France)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer We studied the diffusion of single CD4 receptors on living lymphocytes. Black-Right-Pointing-Pointer This study reveals that CD4 receptors have either a random or confined diffusion. Black-Right-Pointing-Pointer The dynamics of unconfined CD4 receptors was accelerated by a temperature raise. Black-Right-Pointing-Pointer The dynamics of confined CD4 receptors was unchanged by a temperature raise. Black-Right-Pointing-Pointer Our results suggest the existence of two different environments for CD4 receptors. -- Abstract: We investigated the lateral diffusion of the HIV receptor CD4 at the surface of T lymphocytes at 20 Degree-Sign C and 37 Degree-Sign C by Single Particle Tracking using Quantum Dots. We found that the receptors presented two major distinct behaviors that were not equally affected by temperature changes. About half of the receptors showed a random diffusion with a diffusion coefficient increasing upon raising the temperature. The other half of the receptors was permanently or transiently confined with unchanged dynamics on raising the temperature. These observations suggest that two distinct subpopulations of CD4 receptors with different environments are present at the surface of living T lymphocytes.

  10. Asynchronous decentralized method for interconnected electricity markets

    International Nuclear Information System (INIS)

    This paper presents an asynchronous decentralized method to solve the optimization problem of interconnected electricity markets. The proposed method decomposes the optimization problem of combined electricity markets into individual optimization problems. The impact of neighboring markets' information is included in the objective function of the individual market optimization problem by the standard Lagrangian relaxation method. Most decentralized optimization methods use synchronous models of communication to exchange updated market information among markets during the iterative process. In this paper, however, the solutions of the individual optimization problems are coordinated through an asynchronous communication model until they converge to the global optimal solution of combined markets. Numerical examples are presented to demonstrate the advantages of the proposed asynchronous method over the existing synchronous methods. (author)

  11. Label-acquired magnetorotation for biosensing: An asynchronous rotation assay

    Energy Technology Data Exchange (ETDEWEB)

    Hecht, Ariel, E-mail: hecht@umich.ed [University of Michigan, Department of Biomedical Engineering, 2200 Bonisteel, Ann Arbor, MI 48109-2099 (United States); University of Michigan, Department of Chemistry, 930 North University, Ann Arbor, MI 48109-1055 (United States); Kinnunen, Paivo, E-mail: pkkinn@umich.ed [University of Michigan, Department of Chemistry, 930 North University, Ann Arbor, MI 48109-1055 (United States); University of Michigan, Applied Physics Program, 2477 Randall Laboratory, Ann Arbor, MI 48109-1120 (United States); McNaughton, Brandon, E-mail: bmcnaugh@umich.ed [University of Michigan, Department of Biomedical Engineering, 2200 Bonisteel, Ann Arbor, MI 48109-2099 (United States); University of Michigan, Department of Chemistry, 930 North University, Ann Arbor, MI 48109-1055 (United States); University of Michigan, Applied Physics Program, 2477 Randall Laboratory, Ann Arbor, MI 48109-1120 (United States); Kopelman, Raoul, E-mail: kopelman@umich.ed [University of Michigan, Department of Biomedical Engineering, 2200 Bonisteel, Ann Arbor, MI 48109-2099 (United States); University of Michigan, Department of Chemistry, 930 North University, Ann Arbor, MI 48109-1055 (United States); University of Michigan, Applied Physics Program, 2477 Randall Laboratory, Ann Arbor, MI 48109-1120 (United States)

    2011-02-15

    This paper presents a novel application of magnetic particles for biosensing, called label-acquired magnetorotation (LAM). This method is based on a combination of the traditional sandwich assay format with the asynchronous magnetic bead rotation (AMBR) method. In label-acquired magnetorotation, an analyte facilitates the binding of a magnetic label bead to a nonmagnetic solid phase sphere, forming a sandwich complex. The sandwich complex is then placed in a rotating magnetic field, where the rotational frequency of the sandwich complex is a function of the amount of analyte attached to the surface of the sphere. Here, we use streptavidin-coated beads and biotin-coated particles as analyte mimics, to be replaced by proteins and other biological targets in future work. We show this sensing method to have a dynamic range of two orders of magnitude.

  12. Charge, energy and LET spectra of high LET primary and secondary particles in CR-39 plastic nuclear track detectors of the P0006 experiment

    Science.gov (United States)

    Csige, I.; Frigo, L. A.; Benton, E. V.; Oda, K.

    1995-01-01

    We have measured the charge, energy and linear energy transfer (LET) spectra of about 800 high LET (LET(sub infinity) H2O greater than 50 keV/micron) particles in CR-39 plastic nuclear track detectors in the P0006 experiment of LDEF. Primary particles with residual range at the reference surface greater than about 2 microns and secondary particles produced in the detector material with total range greater than about 4 microns were measured. We have used a multi-etch technique and an internal calibration to identify and measure the energy of the particles at the reference surface. The LET spectrum was obtained from the charge and energy distribution of the particles.

  13. Synchronization of Asynchronous Switched Boolean Network.

    Science.gov (United States)

    Zhang, Hao; Wang, Xingyuan; Lin, Xiaohui

    2015-01-01

    In this paper, the complete synchronizations for asynchronous switched Boolean network with free Boolean sequence controllers and close-loop controllers are studied. First, the basic asynchronous switched Boolean network model is provided. With the method of semi-tensor product, the Boolean dynamics is translated into linear representation. Second, necessary and sufficient conditions for ASBN synchronization with free Boolean sequence control and close-loop control are derived, respectively. Third, some illustrative examples are provided to show the efficiency of the proposed methods.

  14. Handbook of asynchronous machines with variable speed

    CERN Document Server

    Razik, Hubert

    2013-01-01

    This handbook deals with the asynchronous machine in its close environment. It was born from a reflection on this electromagnetic converter whose integration in industrial environments takes a wide part. Previously this type of motor operated at fixed speed, from now on it has been integrated more and more in processes at variable speed. For this reason it seemed useful, or necessary, to write a handbook on the various aspects from the motor in itself, via the control and while finishing by the diagnosis aspect. Indeed, an asynchronous motor is used nowadays in industry where variation speed a

  15. Visual tracking of moving object based on particle filter%基于粒子滤波的移动物体视觉跟踪方法

    Institute of Scientific and Technical Information of China (English)

    钱夔; 宋爱国; 熊鹏文

    2011-01-01

    The particle filter algorithm based on color feature has been a research focus in tracking of moving object. This paper presents a particle filter algorithm based on a weighted color histogram to track moving object,using Bhattacharyya distance to describe the color similarity between the particle and the target area,which improves the measurement matching and sample weight updating. The similarity between target template and particle area is calculated, which can locate the target accurately and efficiently. The implementation of this method produces robust results for different situations such as partial occlusion,rotation and shape distortion. The results show that the method is feasible and can perform well in video surveillance and vehicle tracking.%基于颜色特征的粒子滤波算法已成为移动物体跟踪的热点.提出一种基于加权颜色直方图的粒子滤波跟踪算法,利用Bhattacharyya距离来描述粒子与目标区域颜色模型的相似性.实验结果表明:该方法具有较好的实时性与鲁棒性,可应用在视频监控、小车寻迹等场合.

  16. Particle-tracking investigation of the retention of sucker larvae emerging from spawning grounds in Upper Klamath Lake, Oregon

    Science.gov (United States)

    Wood, Tamara M.; Wherry, Susan A.; Simon, David C.; Markle, Douglas F.

    2014-01-01

    This study had two objectives: (1) to use the results of an individual-based particle-tracking model of larval sucker dispersal through the Williamson River delta and Upper Klamath Lake, Oregon, to interpret field data collected throughout Upper Klamath and Agency Lakes, and (2) to use the model to investigate the retention of sucker larvae in the system as a function of Williamson River flow, wind, and lake elevation. This is a follow-up study to work reported in Wood and others (2014) in which the hydrodynamic model of Upper Klamath Lake was combined with an individual-based, particle-tracking model of larval fish entering the lake from spawning areas in the Williamson River. In the previous study, the performance of the model was evaluated through comparison with field data comprising larval sucker distribution collected in 2009 by The Nature Conservancy, Oregon State University (OSU), and the U.S. Geological Survey, primarily from the (at that time) recently reconnected Williamson River Delta and along the eastern shoreline of Upper Klamath Lake, surrounding the old river mouth. The previous study demonstrated that the validation of the model with field data was moderately successful and that the model was useful for describing the broad patterns of larval dispersal from the river, at least in the areas surrounding the river channel immediately downstream of the spawning areas and along the shoreline where larvae enter the lake. In this study, field data collected by OSU throughout the main body of Upper Klamath Lake, and not just around the Williamson River Delta, were compared to model simulation results. Because the field data were collected throughout the lake, it was necessary to include in the simulations larvae spawned at eastern shoreline springs that were not included in the earlier studies. A complicating factor was that the OSU collected data throughout the main body of the lake in 2011 and 2012, after the end of several years of larval drift

  17. The non-anticipation of the asynchronous systems

    OpenAIRE

    Vlad, Serban E.

    2008-01-01

    The asynchronous systems are the models of the asynchronous circuits from the digital electrical engineering and non-anticipation is one of the most important properties in systems theory. Our present purpose is to introduce several concepts of non-anticipation of the asynchronous systems.

  18. Acceptability of an Asynchronous Learning Forum on Mobile Devices

    Science.gov (United States)

    Chang, Chih-Kai

    2010-01-01

    Mobile learning has recently become noteworthy because mobile devices have become popular. To construct an asynchronous learning forum on mobile devices is important because an asynchronous learning forum is always an essential part of networked asynchronous distance learning. However, the input interface in handheld learning devices, which is…

  19. Inferring Latent States and Refining Force Estimates via Hierarchical Dirichlet Process Modeling in Single Particle Tracking Experiments.

    Science.gov (United States)

    Calderon, Christopher P; Bloom, Kerry

    2015-01-01

    Understanding the basis for intracellular motion is critical as the field moves toward a deeper understanding of the relation between Brownian forces, molecular crowding, and anisotropic (or isotropic) energetic forcing. Effective forces and other parameters used to summarize molecular motion change over time in live cells due to latent state changes, e.g., changes induced by dynamic micro-environments, photobleaching, and other heterogeneity inherent in biological processes. This study discusses limitations in currently popular analysis methods (e.g., mean square displacement-based analyses) and how new techniques can be used to systematically analyze Single Particle Tracking (SPT) data experiencing abrupt state changes in time or space. The approach is to track GFP tagged chromatids in metaphase in live yeast cells and quantitatively probe the effective forces resulting from dynamic interactions that reflect the sum of a number of physical phenomena. State changes can be induced by various sources including: microtubule dynamics exerting force through the centromere, thermal polymer fluctuations, and DNA-based molecular machines including polymerases and protein exchange complexes such as chaperones and chromatin remodeling complexes. Simulations aiming to show the relevance of the approach to more general SPT data analyses are also studied. Refined force estimates are obtained by adopting and modifying a nonparametric Bayesian modeling technique, the Hierarchical Dirichlet Process Switching Linear Dynamical System (HDP-SLDS), for SPT applications. The HDP-SLDS method shows promise in systematically identifying dynamical regime changes induced by unobserved state changes when the number of underlying states is unknown in advance (a common problem in SPT applications). We expand on the relevance of the HDP-SLDS approach, review the relevant background of Hierarchical Dirichlet Processes, show how to map discrete time HDP-SLDS models to classic SPT models, and

  20. Inferring Latent States and Refining Force Estimates via Hierarchical Dirichlet Process Modeling in Single Particle Tracking Experiments.

    Directory of Open Access Journals (Sweden)

    Christopher P Calderon

    Full Text Available Understanding the basis for intracellular motion is critical as the field moves toward a deeper understanding of the relation between Brownian forces, molecular crowding, and anisotropic (or isotropic energetic forcing. Effective forces and other parameters used to summarize molecular motion change over time in live cells due to latent state changes, e.g., changes induced by dynamic micro-environments, photobleaching, and other heterogeneity inherent in biological processes. This study discusses limitations in currently popular analysis methods (e.g., mean square displacement-based analyses and how new techniques can be used to systematically analyze Single Particle Tracking (SPT data experiencing abrupt state changes in time or space. The approach is to track GFP tagged chromatids in metaphase in live yeast cells and quantitatively probe the effective forces resulting from dynamic interactions that reflect the sum of a number of physical phenomena. State changes can be induced by various sources including: microtubule dynamics exerting force through the centromere, thermal polymer fluctuations, and DNA-based molecular machines including polymerases and protein exchange complexes such as chaperones and chromatin remodeling complexes. Simulations aiming to show the relevance of the approach to more general SPT data analyses are also studied. Refined force estimates are obtained by adopting and modifying a nonparametric Bayesian modeling technique, the Hierarchical Dirichlet Process Switching Linear Dynamical System (HDP-SLDS, for SPT applications. The HDP-SLDS method shows promise in systematically identifying dynamical regime changes induced by unobserved state changes when the number of underlying states is unknown in advance (a common problem in SPT applications. We expand on the relevance of the HDP-SLDS approach, review the relevant background of Hierarchical Dirichlet Processes, show how to map discrete time HDP-SLDS models to classic SPT

  1. Simulation of magnetic drug targeting through tracheobronchial airways in the presence of an external non-uniform magnetic field using Lagrangian magnetic particle tracking

    International Nuclear Information System (INIS)

    Drug delivery technologies are an important area within biomedicine. Targeted drug delivery aims to reduce the undesired side effects of drug usage by directing or capturing the active agents near a desired site within the body. Herein, a numerical investigation of magnetic drug targeting (MDT) using aerosol drugs named polystyrene particle (PMS40) in human lung is presented considering one-way coupling on the transport and capture of the magnetic particle. A realistic 3D geometry based on CT scan images is provided for CFD simulation. An external non-uniform magnetic field is applied. Parametric investigation is conducted and the influence of particle diameter, magnetic source position, and magnetic number (Mn) on the deposition efficiency and particle behavior is reported. According to the results, the magnetic field increased deposition efficiency of particles in a target region, the efficiency of deposition and MDT technique has a direct relation with increasing the particle diameter for magnetic number of 1 Tesla (T) and lower (Mn≤1(T)). Also it can be seen that there is an inverse relation between the particle diameter and deposition efficiency when Mn is more than 1 (T). - Highlights: • A realistic 3D geometry of human tracheobronchial airway based on CT scan image. • External non-uniform magnetic field applied to target the magnetic drug career. • Lagrangian particle tracking using discrete phase model applied. • The efficiency of deposition is dependent of magnetic number and particle diameter

  2. Simulation of magnetic drug targeting through tracheobronchial airways in the presence of an external non-uniform magnetic field using Lagrangian magnetic particle tracking

    Energy Technology Data Exchange (ETDEWEB)

    Pourmehran, O., E-mail: oveis87@yahoo.com; Rahimi-Gorji, M.; Gorji-Bandpy, M., E-mail: gorji@nit.ac.ir; Gorji, T.B.

    2015-11-01

    Drug delivery technologies are an important area within biomedicine. Targeted drug delivery aims to reduce the undesired side effects of drug usage by directing or capturing the active agents near a desired site within the body. Herein, a numerical investigation of magnetic drug targeting (MDT) using aerosol drugs named polystyrene particle (PMS40) in human lung is presented considering one-way coupling on the transport and capture of the magnetic particle. A realistic 3D geometry based on CT scan images is provided for CFD simulation. An external non-uniform magnetic field is applied. Parametric investigation is conducted and the influence of particle diameter, magnetic source position, and magnetic number (Mn) on the deposition efficiency and particle behavior is reported. According to the results, the magnetic field increased deposition efficiency of particles in a target region, the efficiency of deposition and MDT technique has a direct relation with increasing the particle diameter for magnetic number of 1 Tesla (T) and lower (Mn≤1(T)). Also it can be seen that there is an inverse relation between the particle diameter and deposition efficiency when Mn is more than 1 (T). - Highlights: • A realistic 3D geometry of human tracheobronchial airway based on CT scan image. • External non-uniform magnetic field applied to target the magnetic drug career. • Lagrangian particle tracking using discrete phase model applied. • The efficiency of deposition is dependent of magnetic number and particle diameter.

  3. Increasing Student Engagement Using Asynchronous Learning

    Science.gov (United States)

    Northey, Gavin; Bucic, Tania; Chylinski, Mathew; Govind, Rahul

    2015-01-01

    Student engagement is an ongoing concern for educators because of its positive association with deep learning and educational outcomes. This article tests the use of a social networking site (Facebook) as a tool to facilitate asynchronous learning opportunities that complement face-to-face interactions and thereby enable a stronger learning…

  4. Asynchronous Rumor Spreading on Random Graphs

    CERN Document Server

    Panagiotou, Konstantinos

    2016-01-01

    We perform a thorough study of various characteristics of the asynchronous push-pull protocol for spreading a rumor on Erd\\H{o}s-R\\'enyi random graphs $G_{n,p}$, for any $p>c\\ln(n)/n$ with $c>1$. In particular, we provide a simple strategy for analyzing the asynchronous push-pull protocol on arbitrary graph topologies and apply this strategy to $G_{n,p}$. We prove tight bounds of logarithmic order for the total time that is needed until the information has spread to all nodes. Surprisingly, the time required by the asynchronous push-pull protocol is asymptotically almost unaffected by the average degree of the graph. Similarly tight bounds for Erd\\H{o}s-R\\'enyi random graphs have previously only been obtained for the synchronous push protocol, where it has been observed that the total running time increases significantly for sparse random graphs. Finally, we quantify the robustness of the protocol with respect to transmission and node failures. Our analysis suggests that the asynchronous protocols are particu...

  5. Duration of asynchronous operations in distributed systems

    OpenAIRE

    Makhaniok, Mikhail; Männer, Reinhard

    1995-01-01

    A distributed asynchronous system is investigated. Its processing elements execute common operations concurrently and distributively. They are implemented as combinatorial circuits and exchange data via open collector bus lines. A method is presented to identify and to minimize the duration of an operation and therefore to increase the performance of the system. No hardware modifications are required.

  6. Simulation of Reclaimed-Water Injection and Pumping Scenarios and Particle-Tracking Analysis near Mount Pleasant, South Carolina

    Science.gov (United States)

    Petkewich, Matthew D.; Campbell, Bruce G.

    2009-01-01

    The effect of injecting reclaimed water into the Middendorf aquifer beneath Mount Pleasant, South Carolina, was simulated using a groundwater-flow model of the Coastal Plain Physiographic Province of South Carolina and parts of Georgia and North Carolina. Reclaimed water, also known as recycled water, is wastewater or stormwater that has been treated to an appropriate level so that the water can be reused. The scenarios were simulated to evaluate potential changes in groundwater flow and groundwater-level conditions caused by injecting reclaimed water into the Middendorf aquifer. Simulations included a Base Case and two injection scenarios. Maximum pumping rates were simulated as 6.65, 8.50, and 10.5 million gallons per day for the Base Case, Scenario 1, and Scenario 2, respectively. The Base Case simulation represents a non-injection estimate of the year 2050 groundwater levels for comparison purposes for the two injection scenarios. For Scenarios 1 and 2, the simulated injection of reclaimed water at 3 million gallons per day begins in 2012 and continues through 2050. The flow paths and time of travel for the injected reclaimed water were simulated using particle-tracking analysis. The simulations indicated a general decline of groundwater altitudes in the Middendorf aquifer in the Mount Pleasant, South Carolina, area between 2004 and 2050 for the Base Case and two injection scenarios. For the Base Case, groundwater altitudes generally declined about 90 feet from the 2004 groundwater levels. For Scenarios 1 and 2, although groundwater altitudes initially increased in the Mount Pleasant area because of the simulated injection, these higher groundwater levels declined as Mount Pleasant Waterworks pumping increased over time. When compared to the Base Case simulation, 2050 groundwater altitudes for Scenario 1 are between 15 feet lower to 23 feet higher for production wells, between 41 and 77 feet higher for the injection wells, and between 9 and 23 feet higher for

  7. Breakup of Finite-Size Colloidal Aggregates in Turbulent Flow Investigated by Three-Dimensional (3D) Particle Tracking Velocimetry.

    Science.gov (United States)

    Saha, Debashish; Babler, Matthaus U; Holzner, Markus; Soos, Miroslav; Lüthi, Beat; Liberzon, Alex; Kinzelbach, Wolfgang

    2016-01-12

    Aggregates grown in mild shear flow are released, one at a time, into homogeneous isotropic turbulence, where their motion and intermittent breakup is recorded by three-dimensional particle tracking velocimetry (3D-PTV). The aggregates have an open structure with a fractal dimension of ∼2.2, and their size is 1.4 ± 0.4 mm, which is large, compared to the Kolmogorov length scale (η = 0.15 mm). 3D-PTV of flow tracers allows for the simultaneous measurement of aggregate trajectories and the full velocity gradient tensor along their pathlines, which enables us to access the Lagrangian stress history of individual breakup events. From this data, we found no consistent pattern that relates breakup to the local flow properties at the point of breakup. Also, the correlation between the aggregate size and both shear stress and normal stress at the location of breakage is found to be weaker, when compared with the correlation between size and drag stress. The analysis suggests that the aggregates are mostly broken due to the accumulation of the drag stress over a time lag on the order of the Kolmogorov time scale. This finding is explained by the fact that the aggregates are large, which gives their motion inertia and increases the time for stress propagation inside the aggregate. Furthermore, it is found that the scaling of the largest fragment and the accumulated stress at breakup follows an earlier established power law, i.e., dfrag ∼ σ(-0.6) obtained from laminar nozzle experiments. This indicates that, despite the large size and the different type of hydrodynamic stress, the microscopic mechanism causing breakup is consistent over a wide range of aggregate size and stress magnitude.

  8. In vitro targeted magnetic delivery and tracking of superparamagnetic iron oxide particles labeled stem cells for articular cartilage defect repair.

    Science.gov (United States)

    Feng, Yong; Jin, Xuhong; Dai, Gang; Liu, Jun; Chen, Jiarong; Yang, Liu

    2011-04-01

    To assess a novel cell manipulation technique of tissue engineering with respect to its ability to augment superparamagnetic iron oxide particles (SPIO) labeled mesenchymal stem cells (MSCs) density at a localized cartilage defect site in an in vitro phantom by applying magnetic force. Meanwhile, non-invasive imaging techniques were use to track SPIO-labeled MSCs by magnetic resonance imaging (MRI). Human bone marrow MSCs were cultured and labeled with SPIO. Fresh degenerated human osteochondral fragments were obtained during total knee arthroplasty and a cartilage defect was created at the center. Then, the osteochondral fragments were attached to the sidewalls of culture flasks filled with phosphate-buffered saline (PBS) to mimic the human joint cavity. The SPIO-labeled MSCs were injected into the culture flasks in the presence of a 0.57 Tesla (T) magnetic force. Before and 90 min after cell targeting, the specimens underwent T2-weighted turbo spin-echo (SET2WI) sequence of 3.0 T MRI. MRI results were compared with histological findings. Macroscopic observation showed that SPIO-labeled MSCs were steered to the target region of cartilage defect. MRI revealed significant changes in signal intensity (P<0.01). HE staining exibited that a great number of MSCs formed a three-dimensional (3D) cell "sheet" structure at the chondral defect site. It was concluded that 0.57 T magnetic force permits spatial delivery of magnetically labeled MSCs to the target region in vitro. High-field MRI can serve as an very sensitive non-invasive technique for the visualization of SPIO-labeled MSCs.

  9. Imaging the fine-scale structure of the cellular actin cytoskeleton by Single Particle Tracking and Atomic Force Microscopy

    Science.gov (United States)

    Mustata, Gina-Mirela

    It has been proposed that diffusion in the plasma membrane of eukaryotic cells it is compartmentalized due to the interaction with the underlying actin-based membrane skeleton that comes into close proximity to the lipid bilayer. The cytoskeleton is a dynamic structure that maintains cell shape, enables cell motion, and plays important roles in both intra-cellular transport and cellular division. We show here the evidence of plasma membrane compartmentalization using Single Particle Tracking (SPT) and Atomic Force Microscopy (AFM) imaging. SPT of Quantum dot labeled lipid in the plasma membrane of live normal rat kidney cells show compartments ranging from 325 nm to 391 nm depending on the sampling time. Using AFM imaging of live NRK cell in the presence of phalloidin, the membrane compartmentalization it is visible with the average size of the compartments of 325 +/- 10 nm (the main peak is centered at 260 nm). Further, the underlying membrane skeleton in fixed cells was directly imaged after partial removal of the plasma membrane to reveal size of the membrane skeleton meshwork of 339 +/- 10 nm. A new method of measuring the characteristics of the actin meshwork was proposed. Probing the local compliance of the plasma membrane through the deflection of a soft AFM cantilever we can expect that the stiffness of the membrane will be higher at locations directly above a cortical actin. This new method provided information about the structure of the skeletal meshwork of neuronal cell body predicting an average compartment size of about 132 nm. This was confirmed through SPT of QD-lipid incorporated into the neuronal cell membrane.

  10. Magnetic Particle / Magnetic Resonance Imaging: In-Vitro MPI-Guided Real Time Catheter Tracking and 4D Angioplasty Using a Road Map and Blood Pool Tracer Approach

    OpenAIRE

    Johannes Salamon; Martin Hofmann; Caroline Jung; Michael Gerhard Kaul; Franziska Werner; Kolja Them; Rudolph Reimer; Peter Nielsen; Annika Vom Scheidt; Gerhard Adam; Tobias Knopp; Harald Ittrich

    2016-01-01

    Purpose In-vitro evaluation of the feasibility of 4D real time tracking of endovascular devices and stenosis treatment with a magnetic particle imaging (MPI) / magnetic resonance imaging (MRI) road map approach and an MPI-guided approach using a blood pool tracer. Materials and Methods A guide wire and angioplasty-catheter were labeled with a thin layer of magnetic lacquer. For real time MPI a custom made software framework was developed. A stenotic vessel phantom filled with saline or superp...

  11. 基于粒子滤波和在线学习的目标跟踪%Object Tracking Based on Particle Filtering and Online Learning

    Institute of Scientific and Technical Information of China (English)

    刘海龙; 胡福乔; 赵宇明

    2013-01-01

    针对粒子滤波跟踪丢失目标后较难恢复的问题,提出一种基于粒子滤波和在陑学习的目标跟踪方法。使用粒子滤波有效的跟踪结果作为正训练样本不断更新样本库,将随机蕨作为分类器检测目标位置,当分类器和粒子滤波的检测结果存在较大差异时,重新初始化粒子滤波器。在陑学习采用二维二值特征,具有计算简单、尺度不变和光照不变的特点。实验结果证明,该方法的跟踪结果优于传统的粒子滤波,能够准确地跟踪到被遮挡和陭失再出现的目标。%For the problem that the tracker is hard to be resumed when particle filtering fails to track the target, this paper introduces a method that combines particle filtering with online learning. It uses the validated result of particle filtering as positive sample to update the training set. It uses random ferns as classifier to detect object. When there is a big difference between two results, the particle filter will be reinitialized. Two bit binary pattern is used as the online learning feature. It is easy to be computed, and has invariance to illumination and scale. Experimental result proves that this method has better tracking result than particle filtering and it can track the sheltered and disappeared target.

  12. Bernoulli particle filter with observer altitude for maritime radiation source tracking in the presence of measurement uncertainty

    Institute of Scientific and Technical Information of China (English)

    Luo Xiaobo; Fan Hongqi; Song Zhiyong; Fu Qiang

    2013-01-01

    For maritime radiation source target tracking in particular electronic counter measures (ECM) environment, there exists two main problems which can deteriorate the tracking perfor-mance of traditional approaches. The first problem is the poor observability of the radiation source. The second one is the measurement uncertainty which includes the uncertainty of the target appear-ing/disappearing and the detection uncertainty (false and missed detections). A novel approach is proposed in this paper for tracking maritime radiation source in the presence of measurement uncertainty. To solve the poor observability of maritime radiation source target, using the radiation source motion restriction, the observer altitude information is incorporated into the bearings-only tracking (BOT) method to obtain the unique target localization. Then the two uncertainties in the ECM environment are modeled by the random finite set (RFS) theory and the Bernoulli filtering method with the observer altitude is adopted to solve the tracking problem of maritime radiation source in such context. Simulation experiments verify the validity of the proposed approach for tracking maritime radiation source, and also demonstrate the superiority of the method compared with the traditional integrated probabilistic data association (IPDA) method. The tracking perfor-mance under different conditions, particularly those involving different duration of radiation source opening and switching-off, indicates that the method to solve our problem is robust and effective.

  13. Trajectory exploration within asynchronous binary asteroid systems using refined Lagrangian coherent structures

    Science.gov (United States)

    Shang, Haibin; Wu, Xiaoyu; Cui, Pingyuan

    2016-09-01

    Ground observations have found that asynchronous systems constitute most of the population of the near-Earth binary asteroids. This paper concerns the trajectory of a particle in the asynchronous system which is systematically described using periodic ellipsoidal and spherical body models. Due to the non-autonomous characteristics of the asynchronous system, Lagrangian coherent structures (LCS) are employed to identify the various dynamical behaviors. To enhance the accuracy of LCS, a robust LCS finding algorithm is developed incorporating hierarchical grid refinement, one-dimensional search and variational theory verification. In this way, the intricate dynamical transport boundaries are detected efficiently. These boundaries indicate that a total of 15 types of trajectories exist near asynchronous binary asteroids. According to their Kepler energy variations, these trajectories can be grouped into four basic categories, i.e., transitory, escape, impact and flyby trajectories. Furthermore, the influence of the ellipsoid's spin period on the dynamical behavior is discussed in the context of the change of dynamical regions. We found that the transitory and impact motions occur easily in the synchronous-like binary systems, in which the rotation period of the ellipsoid is nearly equal to that of the mutual orbit. Meanwhile, the results confirm a positive correlation between the spinning rate of the ellipsoid and the probability of the escape and flyby trajectories. The LCS also reveal a marked increase in trajectory diversity after a larger initial energy is selected.

  14. Inhibition Controls Asynchronous States of Neuronal Networks

    Science.gov (United States)

    Treviño, Mario

    2016-01-01

    Computations in cortical circuits require action potentials from excitatory and inhibitory neurons. In this mini-review, I first provide a quick overview of findings that indicate that GABAergic neurons play a fundamental role in coordinating spikes and generating synchronized network activity. Next, I argue that these observations helped popularize the notion that network oscillations require a high degree of spike correlations among interneurons which, in turn, produce synchronous inhibition of the local microcircuit. The aim of this text is to discuss some recent experimental and computational findings that support a complementary view: one in which interneurons participate actively in producing asynchronous states in cortical networks. This requires a proper mixture of shared excitation and inhibition leading to asynchronous activity between neighboring cells. Such contribution from interneurons would be extremely important because it would tend to reduce the spike correlation between neighboring pyramidal cells, a drop in redundancy that could enhance the information-processing capacity of neural networks. PMID:27274721

  15. Existence test for asynchronous interval iterations

    DEFF Research Database (Denmark)

    Madsen, Kaj; Caprani, O.; Stauning, Ole

    1997-01-01

    In the search for regions that contain fixed points ofa real function of several variables, tests based on interval calculationscan be used to establish existence ornon-existence of fixed points in regions that are examined in the course ofthe search. The search can e.g. be performed as a...... synchronous (sequential) interval iteration:In each iteration step all components of the iterate are calculatedbased on the previous iterate. In this case it is straight forward to base simple interval existence and non-existencetests on the calculations done in each step of the iteration. The search can also...... be performed as an asynchronous (parallel) iteration: Only a few components are changed in each stepand this calculation is in general based on components from differentprevious iterates. For the asynchronous iteration it turns out thatsimple tests of existence and non-existence can be based on...

  16. Multiuser Detection in Asynchronous Multibeam Communications

    CERN Document Server

    Chaouech, Helmi; 10.5121/ijwmn.2012.4102

    2012-01-01

    This paper deals with multi-user detection techniques in asynchronous multibeam satellite communications. The proposed solutions are based on successive interference cancellation architecture (SIC) and channel decoding algorithms. The aim of these detection methods is to reduce the effect of cochannel interference due to co-frequency access, and consequently, improves the capacity of the mulitbeam communications systems, by improving frequency reuse. Channel estimation allows the determination of interference coefficients, which helps their effects compensation. The developed multiuser detections techniques are iterative. Therefore, detection quality is improved from a stage to another. Moreover, a signals combining method, which is integrated into these detection solutions, enhances their capability. The proposed solutions are evaluated through computer simulations, where an asynchronous multibeam satellite link is considered over an AWGN channel. The obtained simulation results showed the robustness of thes...

  17. Inhibition Controls Asynchronous States of Neuronal Networks.

    Science.gov (United States)

    Treviño, Mario

    2016-01-01

    Computations in cortical circuits require action potentials from excitatory and inhibitory neurons. In this mini-review, I first provide a quick overview of findings that indicate that GABAergic neurons play a fundamental role in coordinating spikes and generating synchronized network activity. Next, I argue that these observations helped popularize the notion that network oscillations require a high degree of spike correlations among interneurons which, in turn, produce synchronous inhibition of the local microcircuit. The aim of this text is to discuss some recent experimental and computational findings that support a complementary view: one in which interneurons participate actively in producing asynchronous states in cortical networks. This requires a proper mixture of shared excitation and inhibition leading to asynchronous activity between neighboring cells. Such contribution from interneurons would be extremely important because it would tend to reduce the spike correlation between neighboring pyramidal cells, a drop in redundancy that could enhance the information-processing capacity of neural networks.

  18. Asynchronous Nano-Electronics: Preliminary Investigation

    OpenAIRE

    Martin, Alain J.; Prakash, Piyush

    2008-01-01

    This paper is a preliminary investigation in implementing asynchronous QDI logic in molecular nano-electronics, taking into account the restricted geometry, the lack of control on transistor strengths, the high timing variations. We show that the main building blocks of QDI logic can be successfully implemented; we illustrate the approach with the layout of an adder stage. The proposed techniques to improve the reliability of QDI apply to nano-CMOS as well.

  19. Asynchronous exponential growth of a bacterial population

    Directory of Open Access Journals (Sweden)

    Mohamed Boulanouar

    2014-01-01

    Full Text Available In this work, we complete a study started earlier in [1,2] wherein a model of growing bacterial population has been the matter of a mathematical analysis. We show that the full model is governed by a strongly continuous semigroup. Beside the positivity and the irreducibility of the generated semigroup, we describe its asymptotic behavior in the uniform topology which leads to the asynchronous exponential growth of the bacterial population.

  20. Accurate estimator of correlations between asynchronous signals

    OpenAIRE

    Toth, Bence; Kertesz, Janos

    2008-01-01

    The estimation of the correlation between time series is often hampered by the asynchronicity of the signals. Cumulating data within a time window suppresses this source of noise but weakens the statistics. We present a method to estimate correlations without applying long time windows. We decompose the correlations of data cumulated over a long window using decay of lagged correlations as calculated from short window data. This increases the accuracy of the estimated correlation significantl...

  1. Particle-tracking investigation of the retention of sucker larvae emerging from spawning grounds in Upper Klamath Lake, Oregon

    Science.gov (United States)

    Wood, Tamara M.; Wherry, Susan A.; Simon, David C.; Markle, Douglas F.

    2014-01-01

    This study had two objectives: (1) to use the results of an individual-based particle-tracking model of larval sucker dispersal through the Williamson River delta and Upper Klamath Lake, Oregon, to interpret field data collected throughout Upper Klamath and Agency Lakes, and (2) to use the model to investigate the retention of sucker larvae in the system as a function of Williamson River flow, wind, and lake elevation. This is a follow-up study to work reported in Wood and others (2014) in which the hydrodynamic model of Upper Klamath Lake was combined with an individual-based, particle-tracking model of larval fish entering the lake from spawning areas in the Williamson River. In the previous study, the performance of the model was evaluated through comparison with field data comprising larval sucker distribution collected in 2009 by The Nature Conservancy, Oregon State University (OSU), and the U.S. Geological Survey, primarily from the (at that time) recently reconnected Williamson River Delta and along the eastern shoreline of Upper Klamath Lake, surrounding the old river mouth. The previous study demonstrated that the validation of the model with field data was moderately successful and that the model was useful for describing the broad patterns of larval dispersal from the river, at least in the areas surrounding the river channel immediately downstream of the spawning areas and along the shoreline where larvae enter the lake. In this study, field data collected by OSU throughout the main body of Upper Klamath Lake, and not just around the Williamson River Delta, were compared to model simulation results. Because the field data were collected throughout the lake, it was necessary to include in the simulations larvae spawned at eastern shoreline springs that were not included in the earlier studies. A complicating factor was that the OSU collected data throughout the main body of the lake in 2011 and 2012, after the end of several years of larval drift

  2. Blending Online Asynchronous and Synchronous Learning

    Directory of Open Access Journals (Sweden)

    Lisa C. Yamagata-Lynch

    2014-04-01

    Full Text Available In this article I will share a qualitative self-study about a 15-week blended 100% online graduate level course facilitated through synchronous meetings on Blackboard Collaborate and asynchronous discussions on Blackboard. I taught the course at the University of Tennessee (UT during the spring 2012 semester and the course topic was online learning environments. The primary research question of this study was: How can the designer/instructor optimize learning experiences for students who are studying about online learning environments in a blended online course relying on both synchronous and asynchronous technologies? I relied on student reflections of course activities during the beginning, middle, and the end of the semester as the primary data source to obtain their insights regarding course experiences. Through the experiences involved in designing and teaching the course and engaging in this study I found that there is room in the instructional technology research community to address strategies for facilitating online synchronous learning that complement asynchronous learning. Synchronous online whole class meetings and well-structured small group meetings can help students feel a stronger sense of connection to their peers and instructor and stay engaged with course activities. In order to provide meaningful learning spaces in synchronous learning environments, the instructor/designer needs to balance the tension between embracing the flexibility that the online space affords to users and designing deliberate structures that will help them take advantage of the flexible space.

  3. Evidence for the Heavy Baryon Resonance State Lambda b*0 Observed with the CDF II Detector, and Studies of New Particle Tracking Technologies Using the LANSCE Proton Beam

    Science.gov (United States)

    Palni, Prabhakar

    To discover and probe the properties of new particles, we need to collide highly energetic particles. The Tevatron at Fermilab has collided protons and anti-protons at very high energies. These collisions produce short lived and stable particles, some known and some previously unknown. The CDF detector is used to study the products of such collisions and discover new elementary particles. To study the interaction between high energy charged particles and the detector materials often requires development of new instruments. Thus this dissertation involves a measurement at a contemporary experiment and development of technologies for related future experiments that will build on the contemporary one. Using data from proton-antiproton collisions at sqrt(s) = 1.96TeV recorded by the CDF II detector at the Fermilab Tevatron, evidence for the excited resonance state Lambda_b. *0 is presented in its Lambda_b. 0 pi. + pi. - decay,followed by the Lambda_b. 0 -> Lambda_c. + pi. - and Lambda_c. + -> p K. - pi. +decays. The analysis is based on a data sample corresponding to an integrated luminosity of 9.6 fb. -1 collected by an online event selection process basedon charged particle tracks displaced from the proton-antiproton interaction point. The significance of the observed signal is 3.5sigma The mass of the observed state is found to be 5919.22 +/- 0.76 MeV/c 2 in agreement with similar findings in proton-proton collision experiments. To predict the radiation damage to the components of new particle tracking detectors, prototype devices are irradiated at test beam facilities that reproduce the radiation conditions expected. The profile of the test beam and the fluence applied per unit time must be known. We have developed a technique to monitor in real time the beam profile and fluence using an array of pin semiconductor diodes whose forward voltage is linear with fluence over the fluence regime relevant to, for example, silicon tracking detectors in the LHC upgrade era

  4. Search for long-lived supersymmetry particles by signature of a high track-multiplicity displaced vertex using the LHC-ATLAS Experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00360876

    Long-lived supersymmetry (SUSY) particles decaying within the tracking volume of the LHC-ATLAS Experiment can be reconstructed as a displaced vertex (DV). The search strategy involves attempting to reassemble the decay point of the long-lived particles (LLPs) by fitting vertices from the trajectories arising from the charged decay products. A search, looking for a signature of a massive high track-multiplicity DV has been conducted using data collected during 2012 by the LHC-ATLAS Experiment at $\\sqrt{s}~=~8$ TeV, equaling to an integrated luminosity of 20.3 fb$^{-1}$. A signature of a massive displaced vertex is especially powerful due to the lack of any heavy long-lived standard model particles. Thereby, giving an analysis that is nearly background free. This dissertation describes the new, much more generic, "$DV+\\text{jets}$" channel. In this channel events with high momentum jets and at least one displaced vertex are considered. Eliminating the requirement of an associated $\\mu$ generated, to date of w...

  5. Bayesian multiple target tracking

    CERN Document Server

    Streit, Roy L

    2013-01-01

    This second edition has undergone substantial revision from the 1999 first edition, recognizing that a lot has changed in the multiple target tracking field. One of the most dramatic changes is in the widespread use of particle filters to implement nonlinear, non-Gaussian Bayesian trackers. This book views multiple target tracking as a Bayesian inference problem. Within this framework it develops the theory of single target tracking, multiple target tracking, and likelihood ratio detection and tracking. In addition to providing a detailed description of a basic particle filter that implements

  6. EPOS for Coordination of Asynchronous Sensor Webs Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop, integrate, and deploy software-based tools to coordinate asynchronous, distributed missions and optimize observation planning spanning simultaneous...

  7. Designing Asynchronous Circuits for Low Power: An IFIR Filter

    DEFF Research Database (Denmark)

    Nielsen, Lars Skovby; Sparsø, Jens

    1999-01-01

    This paper addresses the design of asynchronous circuits for low power through an example: a filter bank for a digital hearing aid. The asynchronous design re-implements an existing synchronous circuit which is used in a commercial product. For comparison, both designs have been fabricated...... by numerically small samples). Apart from the improved RAM design, these measures are only viable in an asynchronous design. The principles and techniques explained in this paper are of a general nature, and they apply to the design of asynchronous low-power digital signal-processing circuits in a broader...

  8. Track finding efficiency in BABAR

    International Nuclear Information System (INIS)

    We describe several studies to measure the charged track reconstruction efficiency and asymmetry of the BABAR detector. The first two studies measure the tracking efficiency of a charged particle using τ and initial state radiation decays. The third uses the τ decays to study the asymmetry in tracking, the fourth measures the tracking efficiency for low momentum tracks, and the last measures the reconstruction efficiency of KS0 particles. The first section also examines the stability of the measurements vs. BABAR running periods

  9. Field calculations, single-particle tracking, and beam dynamics with space charge in the electron lens for the Fermilab Integrable Optics Test Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Noll, Daniel [Goethe Univ., Frankfurt (Germany); Stancari, Giulio [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-11-17

    An electron lens is planned for the Fermilab Integrable Optics Test Accelerator as a nonlinear element for integrable dynamics, as an electron cooler, and as an electron trap to study space-charge compensation in rings. We present the main design principles and constraints for nonlinear integrable optics. A magnetic configuration of the solenoids and of the toroidal section is laid out. Singleparticle tracking is used to optimize the electron path. Electron beam dynamics at high intensity is calculated with a particle-in-cell code to estimate current limits, profile distortions, and the effects on the circulating beam. In the conclusions, we summarize the main findings and list directions for further work.

  10. High speed versus pulsed images for micro-particle image velocimetry: a direct comparison of red blood cells versus fluorescing tracers as tracking particles.

    Science.gov (United States)

    Pitts, Katie L; Fenech, Marianne

    2013-10-01

    High speed photography in micro-particle image velocimetry (μPIV) using red blood cells as tracer particles and the use of fluorescing tracer particles (in conjunction with pulsed images) are directly compared by using both methods simultaneously. Measurements are taken on the same blood sample in the same microchip using both methods. This work directly and statistically compares the two methods of μPIV measurement in a controlled in vitro environment for the first time in literature. The pulsed method using fluorescing tracer particles is found to decrease the depth of correlation as expected, and to better represent the shape of the velocity profile. Two methods of velocity characterization are used (single and double parameter) and the pulsed images provide better shape representation in both cases.

  11. High speed versus pulsed images for micro-particle image velocimetry: a direct comparison of red blood cells versus fluorescing tracers as tracking particles

    International Nuclear Information System (INIS)

    High speed photography in micro-particle image velocimetry (μPIV) using red blood cells as tracer particles and the use of fluorescing tracer particles (in conjunction with pulsed images) are directly compared by using both methods simultaneously. Measurements are taken on the same blood sample in the same microchip using both methods. This work directly and statistically compares the two methods of μPIV measurement in a controlled in vitro environment for the first time in literature. The pulsed method using fluorescing tracer particles is found to decrease the depth of correlation as expected, and to better represent the shape of the velocity profile. Two methods of velocity characterization are used (single and double parameter) and the pulsed images provide better shape representation in both cases. (paper)

  12. 基于Beowulf机群中改进粒子滤波的3D人体运动跟踪%Three-dimension human motion tracking based improved particle filter on Beowulf cluster system

    Institute of Scientific and Technical Information of China (English)

    李敏; 宋曰聪; 吴斌; 彭保

    2015-01-01

    According to the problem that the standard particle filter tracking algorithm in video 3D human motion track-ing cannot meet tracking accuracy and real time tracking at the same time for its intensive computation and particle degen-eracy and tracking failure. A novel improvement particle filter algorithm is proposed based on Beowulf cluster system par-allel computing. The new algorithm can realize automatic recovery from tracking failure by automatic initialization of 3D human body model parameters and adjustment of particle amount and template. The migration particle filter parallel algo-rithm which based on task dynamic allocation and low consumption communication strategy in Beowulf cluster system can overcome particle degeneracy problem and improve computation speed. The experimental result shows that particle degeneracy and tracking failure problems have been alleviated effectively, the computing time has been reduced, the track-ing precision has been improved, and the new way can meet the need of tracking accuracy and real time tracking at the same time.%针对标准的粒子滤波算法在视频三维人体运动跟踪中存在的计算量巨大、粒子退化、跟踪失效而无法同时满足跟踪精度和跟踪实时性要求的问题,提出了基于Beowulf机群中改进的粒子滤波新算法。新算法通过三维人体模型参数的自动初始化、粒子数目和模板的调整来实现跟踪失效的自动恢复,基于任务动态分配策略、低开销通信策略设计的Beowulf机群中的迁移式粒子滤波并行算法克服了粒子退化问题和提高了计算速度。实验结果显示:新方法有效地减轻了粒子退化和跟踪失效问题,降低了计算时间,提高了跟踪精度,能够同时满足三维人体运动跟踪精度和实时性的要求。

  13. Three-dimensional particle tracking around microstructures in water via total internal reflection fluorescence microscopy and refractive-index-matching method

    Science.gov (United States)

    Unno, Noriyuki; Nakata, Shuichiro; Satake, Shin-ichi; Taniguchi, Jun

    2016-07-01

    Multilayer nanoparticle image velocimetry (MnPIV) with a refractive-index-matching method is powerful technique for x- y- z (3D) flow measurement, because it can detect the 3D position of fluorescent particles with submicron resolution. In MnPIV, the intensity of fluorescence of a particle is used to estimate its z-position. However, it has been difficult to measure 3D flows around microstructures in water by total internal reflection fluorescence microscopy because of light scattering caused by the different refractive indices of the structures and the working fluid. By using a thermal nanoimprinting technique, we succeeded in fabricating microstructures from a polymer resin whose refractive index is equal to that of water, and we used these microstructures to perform MnPIV in water. As a result of the match between the refractive index of water and that of the microstructures, we were able to perform 3D tracking of nanoparticles around the microstructures in water.

  14. Field calculations, single-particle tracking, and beam dynamics with space charge in the electron lens for the Fermilab Integrable Optics Test Accelerator

    CERN Document Server

    Noll, Daniel

    2015-01-01

    An electron lens is planned for the Fermilab Integrable Optics Test Accelerator as a nonlinear element for integrable dynamics, as an electron cooler, and as an electron trap to study space-charge compensation in rings. We present the main design principles and constraints for nonlinear integrable optics. A magnetic configuration of the solenoids and of the toroidal section is laid out. Single-particle tracking is used to optimize the electron path. Electron beam dynamics at high intensity is calculated with a particle-in-cell code to estimate current limits, profile distortions, and the effects on the circulating beam. In the conclusions, we summarize the main findings and list directions for further work.

  15. From asynchronous logic to the standard model to superflight to the stars

    CERN Document Server

    Blaha, Stephen

    2011-01-01

    This edition is the latest in a series of books by this author that have appeared in the past ten years that seek to make sense of the form of The Standard Model. Previously The Standard Model was viewed as a hodgepodge of particles symmetries and features that worked experimentally but was only an approximation to a "true" fundamental theory. The overall purpose of this series of books was to show that the form of The Standard Model is based on certain fundamental principles that ultimately emanate from Logic, Asynchronous Logic in particular. Physical phenomena are asynchronous. The simplest form of Asynchronous Logic has a 4-valued logic that maps naturally to Dirac-like equations. Upon this bridge The Standard Model is constructed with parity violation, particle symmetries SU(3)SU(2)U(1)U(1), and a spin ½ fermion spectrum with four generations of four fermion species split into quarks and leptons. Two species of WIMPs are also derived. A new formulation of Logic is presented. A major application...

  16. Normalized and asynchronous mirror alignment for Cherenkov telescopes

    Science.gov (United States)

    Ahnen, M. L.; Baack, D.; Balbo, M.; Bergmann, M.; Biland, A.; Blank, M.; Bretz, T.; Bruegge, K. A.; Buss, J.; Domke, M.; Dorner, D.; Einecke, S.; Hempfling, C.; Hildebrand, D.; Hughes, G.; Lustermann, W.; Mannheim, K.; Mueller, S. A.; Neise, D.; Neronov, A.; Noethe, M.; Overkemping, A.-K.; Paravac, A.; Pauss, F.; Rhode, W.; Shukla, A.; Temme, F.; Thaele, J.; Toscano, S.; Vogler, P.; Walter, R.; Wilbert, A.

    2016-09-01

    Imaging Atmospheric Cherenkov Telescopes (IACTs) need imaging optics with large apertures and high image intensities to map the faint Cherenkov light emitted from cosmic ray air showers onto their image sensors. Segmented reflectors fulfill these needs, and as they are composed from mass production mirror facets they are inexpensive and lightweight. However, as the overall image is a superposition of the individual facet images, alignment is a challenge. Here we present a computer vision based star tracking alignment method, which also works for limited or changing star light visibility. Our method normalizes the mirror facet reflection intensities to become independent of the reference star's intensity or the cloud coverage. Using two CCD cameras, our method records the mirror facet orientations asynchronously of the telescope drive system, and thus makes the method easy to integrate into existing telescopes. It can be combined with remote facet actuation, but does not require one to work. Furthermore, it can reconstruct all individual mirror facet point spread functions without moving any mirror. We present alignment results on the 4 m First Geiger-mode Avalanche Cherenkov Telescope (FACT).

  17. Children's Comprehension of Sentences with Focus Particles and the Role of Cognitive Control: An Eye Tracking Study with German-Learning 4-Year-Olds.

    Science.gov (United States)

    Höhle, Barbara; Fritzsche, Tom; Müller, Anja

    2016-01-01

    Children's interpretations of sentences containing focus particles do not seem adult-like until school age. This study investigates how German 4-year-old children comprehend sentences with the focus particle 'nur' (only) by using different tasks and controlling for the impact of general cognitive abilities on performance measures. Two sentence types with 'only' in either pre-subject or pre-object position were presented. Eye gaze data and verbal responses were collected via the visual world paradigm combined with a sentence-picture verification task. While the eye tracking data revealed an adult-like pattern of focus particle processing, the sentence-picture verification replicated previous findings of poor comprehension, especially for 'only' in pre-subject position. A second study focused on the impact of general cognitive abilities on the outcomes of the verification task. Working memory was related to children's performance in both sentence types whereas inhibitory control was selectively related to the number of errors for sentences with 'only' in pre-subject position. These results suggest that children at the age of 4 years have the linguistic competence to correctly interpret sentences with focus particles, which--depending on specific task demands--may be masked by immature general cognitive abilities.

  18. Integrating Asynchronous Digital Design Into the Computer Engineering Curriculum

    Science.gov (United States)

    Smith, S. C.; Al-Assadi, W. K.; Di, J.

    2010-01-01

    As demand increases for circuits with higher performance, higher complexity, and decreased feature size, asynchronous (clockless) paradigms will become more widely used in the semiconductor industry, as evidenced by the International Technology Roadmap for Semiconductors' (ITRS) prediction of a likely shift from synchronous to asynchronous design…

  19. Asynchronous Learning Sources in a High-Tech Organization

    Science.gov (United States)

    Bouhnik, Dan; Giat, Yahel; Sanderovitch, Yafit

    2009-01-01

    Purpose: The purpose of this study is to characterize learning from asynchronous sources among research and development (R&D) personnel. It aims to examine four aspects of asynchronous source learning: employee preferences regarding self-learning; extent of source usage; employee satisfaction with these sources and the effect of the sources on the…

  20. Magnetic resonance hypointensive signal primarily originates from extracellular iron particles in the long-term tracking of mesenchymal stem cells transplanted in the infarcted myocardium

    Directory of Open Access Journals (Sweden)

    Huang Z

    2015-03-01

    Full Text Available Zheyong Huang,1,* Chenguang Li,1,* Shan Yang,2 Jianfeng Xu,1 Yunli Shen,3 Xinxing Xie,4 Yuxiang Dai,1 Hao Lu,1 Hui Gong,5 Aijun Sun,1 Juying Qian,1 Junbo Ge1 1Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, People’s Republic of China; 2Department of Radiology, Zhongshan Hospital, Fudan University, Shanghai, People’s Republic of China; 3Department of Cardiology, Shanghai East Hospital, Tongji University, Shanghai, People’s Republic of China; 4Department of Cardiology, Qianfoshan Hospital, Shandong University, Jinan, Shandong Province, People’s Republic of China; 5Institute of Biomedical Science, Fudan University, Shanghai, People’s Republic of China *These authors contributed equally to this work Purpose: The long-lasting hypointensities in cardiac magnetic resonance (CMR were believed to originate from superparamagnetic iron oxide (SPIO-engulfed macrophages during long-term stem cell tracking. However, the iron clearance capacity of the ischemic heart was limited. Therefore, we speculated that the extracellular SPIO particles may also be involved in the generation of false-positive signals.Methods and results: Male swine mesenchymal stem cells (MSCs were incubated with SPIO for 24 hours, and SPIO labeling had no significant effects on either cell viability or differentiation. In vitro studies showed that magnetic resonance failed to distinguish SPIO from living SPIO-MSCs or dead SPIO-MSCs. Two hours after the establishment of the female swine acute myocardial infarction model, 2×107 male SPIO-labeled MSCs (n=5 or unlabeled MSCs (n=5 were transextracardially injected into the infarcted myocardium at ten distinct sites. In vivo CMR with T2 star weighted imaging-flash-2D sequence revealed a signal void corresponding to the initial SPIO-MSC injection sites. At 6 months after transplantation, CMR identified 32 (64% of the 50 injection sites, where massive Prussian blue-positive iron

  1. Asynchronicity of facial blood perfusion in migraine.

    Directory of Open Access Journals (Sweden)

    Nina Zaproudina

    Full Text Available Asymmetrical changes in blood perfusion and asynchronous blood supply to head tissues likely contribute to migraine pathophysiology. Imaging was widely used in order to understand hemodynamic variations in migraine. However, mapping of blood pulsations in the face of migraineurs has not been performed so far. We used the Blood Pulsation Imaging (BPI technique, which was recently developed in our group, to establish whether 2D-imaging of blood pulsations parameters can reveal new biomarkers of migraine. BPI characteristics were measured in migraineurs during the attack-free interval and compared to healthy subjects with and without a family history of migraine. We found a novel phenomenon of transverse waves of facial blood perfusion in migraineurs in contrast to healthy subjects who showed synchronous blood delivery to both sides of the face. Moreover, the amplitude of blood pulsations was symmetrically distributed over the face of healthy subjects, but asymmetrically in migraineurs and subjects with a family history of migraine. In the migraine patients we found a remarkable correlation between the side of unilateral headache and the direction of the blood perfusion wave. Our data suggest that migraine is associated with lateralization of blood perfusion and asynchronous blood pulsations in the facial area, which could be due to essential dysfunction of the autonomic vascular control in the face. These findings may further enhance our understanding of migraine pathophysiology and suggest new easily available biomarkers of this pathology.

  2. Tracking the pathway of diesel exhaust particles from the nose to the brain by X-ray florescence analysis

    Science.gov (United States)

    Matsui, Yasuto; Sakai, Nobumitsu; Tsuda, Akira; Terada, Yasuko; Takaoka, Masaki; Fujimaki, Hidekazu; Uchiyama, Iwao

    2009-08-01

    Studies have shown that exposure to nano-sized particles (system through the olfactory nerve. Translocation commonly occurs via inhalation, ingestion and skin uptake. Little information is available on the specific pathway of cellular localization of nano-sized particles in the olfactory bulb. The nano-sized particles entrance into the postsynaptics cell is of particular interest because the mitral cell projects to the central nucleus of the amygdala and the piriform cortex. Therefore, our objective in this follow-up study has been to determine whether or not the mitral cells project nano-sized particles to the brain. Nano-sized particles in this study were generated using diesel exhaust. Lab mice were exposed for a period of 4 weeks. We employed synchrotron radiation (SPring-8, Japan) to determine the concentration levels of metal in the olfactory neuron pathway. Metal levels were assayed by mapping, using X-ray fluorescence analysis. The major metal components measured in the filter that collected the inhaled diesel exhaust particles were calcium, copper, iron, nickel and zinc. Our studies reveal an increase in the amount of nano-sized particles in the glomerular layer as well as in the neurons in the olfactory epithelium. Higher levels of nickel and iron were found in the olfactory epithelium's lamina propria mucosae in comparison to that in the control group. Higher levels of iron also were observed in the glomerular layer. Our studies do not clarify the specifics of metal adhesion and detachment. This remains to be one of the key issues requiring further clarification.

  3. Simulation of DNA Damage in Human Cells from Space Radiation Using a Physical Model of Stochastic Particle Tracks and Chromosomes

    Science.gov (United States)

    Ponomarev, Artem; Plante, Ianik; Hada, Megumi; George, Kerry; Wu, Honglu

    2015-01-01

    The formation of double-strand breaks (DSBs) and chromosomal aberrations (CAs) is of great importance in radiation research and, specifically, in space applications. We are presenting a recently developed model, in which chromosomes simulated by NASARTI (NASA Radiation Tracks Image) is combined with nanoscopic dose calculations performed with the Monte-Carlo simulation by RITRACKS (Relativistic Ion Tracks) in a voxelized space. The model produces the number of DSBs, as a function of dose for high-energy iron, oxygen, and carbon ions, and He ions. The combined model calculates yields of radiation-induced CAs and unrejoined chromosome breaks in normal and repair deficient cells. The merged computational model is calibrated using the relative frequencies and distributions of chromosomal aberrations reported in the literature. The model considers fractionated deposition of energy to approximate dose rates of the space flight environment. The merged model also predicts of the yields and sizes of translocations, dicentrics, rings, and more complex-type aberrations formed in the G0/G1 cell cycle phase during the first cell division after irradiation.

  4. Mesenchymal stem cell in vitro labeling by hybrid fluorescent magnetic polymeric particles for application in cell tracking.

    Science.gov (United States)

    Supokawej, Aungkura; Nimsanor, Natakarn; Sanvoranart, Tanwarat; Kaewsaneha, Chariya; Hongeng, Suradej; Tangboriboonrat, Pramuan; Jangpatarapongsa, Kulachart

    2015-12-01

    Mesenchymal stem cells (MSCs) are a type of adult stem cell that contains multi-differentiation and proliferative properties and that shows high treatment implications for many clinical problems. The outcome of stem cell transplantation is still limited due to many factors, especially their survival and their interaction with the microenvironment after transplantation. Molecular imaging is a challenging technique that has been used to overcome this limitation and is based on the concept of labeling cells with tractable, visible, and non-toxic materials to track the cells after transplantation. In this study, magnetic polymeric nanoparticles (MPNPs) were used to directly label Wharton's jelly-derived MSCs (WJ-MSCs). After labeling, the growth rate and the viability of the MSCs as well as the time of exposure were determined. The 3D images of WJ-MSCs labeled with MPNPs for 24 h were created using confocal microscopy. The results showed that, after incubation with fluorescent MPNPs for over 8 h, the growth rate and cell viability of the WJ-MSCs was similar to those of the control. Three-dimensional imaging revealed that the fluorescent MPNPs could infiltrate into the cells and spread into the cytoplasm, which suggests that the synthesized fluorescent MPNPs could possibly label MSCs for cell tracking study and be further developed for in vivo applications. PMID:25893425

  5. Probability-based particle detection that enables threshold-free and robust in vivo single-molecule tracking.

    Science.gov (United States)

    Smith, Carlas S; Stallinga, Sjoerd; Lidke, Keith A; Rieger, Bernd; Grunwald, David

    2015-11-01

    Single-molecule detection in fluorescence nanoscopy has become a powerful tool in cell biology but can present vexing issues in image analysis, such as limited signal, unspecific background, empirically set thresholds, image filtering, and false-positive detection limiting overall detection efficiency. Here we present a framework in which expert knowledge and parameter tweaking are replaced with a probability-based hypothesis test. Our method delivers robust and threshold-free signal detection with a defined error estimate and improved detection of weaker signals. The probability value has consequences for downstream data analysis, such as weighing a series of detections and corresponding probabilities, Bayesian propagation of probability, or defining metrics in tracking applications. We show that the method outperforms all current approaches, yielding a detection efficiency of >70% and a false-positive detection rate of <5% under conditions down to 17 photons/pixel background and 180 photons/molecule signal, which is beneficial for any kind of photon-limited application. Examples include limited brightness and photostability, phototoxicity in live-cell single-molecule imaging, and use of new labels for nanoscopy. We present simulations, experimental data, and tracking of low-signal mRNAs in yeast cells.

  6. Hyperspectral multiplex single-particle tracking of different receptor subtypes labeled with quantum dots in live neurons

    Science.gov (United States)

    Labrecque, Simon; Sylvestre, Jean-Philippe; Marcet, Stephane; Mangiarini, Francesca; Bourgoin, Brice; Verhaegen, Marc; Blais-Ouellette, Sébastien; De Koninck, Paul

    2016-04-01

    The efficacy of existing therapies and the discovery of innovative treatments for central nervous system (CNS) diseases have been limited by the lack of appropriate methods to investigate complex molecular processes at the synaptic level. To improve our capability to investigate complex mechanisms of synaptic signaling and remodeling, we designed a fluorescence hyperspectral imaging platform to simultaneously track different subtypes of individual neurotransmitter receptors trafficking in and out of synapses. This imaging platform allows simultaneous image acquisition of at least five fluorescent markers in living neurons with a high-spatial resolution. We used quantum dots emitting at different wavelengths and functionalized to specifically bind to single receptors on the membrane of living neurons. The hyperspectral imaging platform enabled the simultaneous optical tracking of five different synaptic proteins, including subtypes of glutamate receptors (mGluR and AMPAR) and postsynaptic signaling proteins. It also permitted the quantification of their mobility after treatments with various pharmacological agents. This technique provides an efficient method to monitor several synaptic proteins at the same time, which could accelerate the screening of effective compounds for treatment of CNS disorders.

  7. High-speed (20  kHz) digital in-line holography for transient particle tracking and sizing in multiphase flows.

    Science.gov (United States)

    Guildenbecher, Daniel R; Cooper, Marcia A; Sojka, Paul E

    2016-04-10

    High-speed (20 kHz) digital in-line holography (DIH) is applied for 3D quantification of the size and velocity of fragments formed from the impact of a single water drop onto a thin film of water and burning aluminum particles from the combustion of a solid rocket propellant. To address the depth-of-focus problem in DIH, a regression-based multiframe tracking algorithm is employed, and out-of-plane experimental displacement accuracy is shown to be improved by an order-of-magnitude. Comparison of the results with previous DIH measurements using low-speed recording shows improved positional accuracy with the added advantage of detailed resolution of transient dynamics from single experimental realizations. The method is shown to be particularly advantageous for quantification of particle mass flow rates. For the investigated particle fields, the mass flows rates, which have been automatically measured from single experimental realizations, are found to be within 8% of the expected values. PMID:27139851

  8. A search for new heavy particles in events with highly ionising, short tracks at the CMS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Lenz, Teresa

    2016-06-15

    The main focus of the CMS experiment at the Large Hadron Collider (LHC) is to search for physics beyond the Standard Model and to measure Standard Model parameters. For both purposes it is essential to determine important performance parameters of the CMS detector. The here presented thesis contributes in a twofold way to the physics program of CMS. In the first part of this thesis, a search for physics beyond the Standard Model is presented. It is motivated by supersymmetric models with nearly mass-degenerate lightest neutralinos and lightest charginos. The small mass gap between chargino and neutralino can lead to long lifetimes of the chargino due to phase space suppression. Thus, the chargino can reach the tracking system before its decay. The here presented search targets chargino lifetimes of cτ ∼ 1-30 cm where most of the charginos decay in the first layers of the tracker. This search aims at increasing the search sensitivity of existing searches with respect to these models in a twofold way: first, the inclusion of tracks down to three measurements in the tracking system, and second, the discrimination against Standard Model background by the energy loss per path length. The search is performed on 19.7 fb{sup -1} of data recorded at the CMS experiment at a centre-of-mass energy of 8 TeV. No excess above the Standard Model expectation is found and the supersymmetric parameter space is constrained. The search can exclude supersymmetric models with chargino masses of 100 GeV down to lifetimes of cτ=2 cm and models with masses of 500 GeV down to lifetimes of cτ=70 cm. Current limits are confirmed and improvements of the order of 10-40 GeV in chargino mass are achieved. In the second part of the thesis, a measurement of the jet transverse-momentum resolution at 8 TeV at the CMS experiment is presented. In order to exploit the good energy resolution of the electromagnetic calorimeter of the CMS detector, the measurement is performed using γ+jet events. Due

  9. Asynchronous machines. Direct torque control; Machines asynchrones. Commande par controle direct de couple

    Energy Technology Data Exchange (ETDEWEB)

    Fornel, B. de [Institut National Polytechnique, 31 - Toulouse (France)

    2006-05-15

    The asynchronous machine, with its low cost and robustness, is today the most widely used motor to make speed variators. However, its main drawback is that the same current generates both the magnetic flux and the torque, and thus any torque variation creates a flux variation. Such a coupling gives to the asynchronous machine a nonlinear behaviour which makes its control much more complex. The direct self control (DSC) method has been developed to improve the low efficiency of the scalar control method and for the specific railway drive application. The direct torque control (DTC) method is derived from the DSC method but corresponds to other type of applications. The DSC and DTC algorithms for asynchronous motors are presented in this article: 1 - direct control of the stator flux (DSC): principle, flux control, torque control, switching frequency of the inverter, speed estimation; 2 - direct torque control (DTC): principle, electromagnetic torque derivative, signals shape and switching frequency, some results, DTC speed variator without speed sensor, DTC application to multi-machine multi-converter systems; 3 - conclusion. (J.S.)

  10. Registration procedure for spatial correlation of physical energy deposition of particle irradiation and cellular response utilizing cell-fluorescent ion track hybrid detectors

    Science.gov (United States)

    Niklas, M.; Zimmermann, F.; Schlegel, J.; Schwager, C.; Debus, J.; Jäkel, O.; Abdollahi, A.; Greilich, S.

    2016-09-01

    The hybrid technology cell-fluorescent ion track hybrid detector (Cell-Fit-HD) enables the investigation of radiation-related cellular events along single ion tracks on the subcellular scale in clinical ion beams. The Cell-Fit-HD comprises a fluorescent nuclear track detector (FNTD, the physical compartment), a device for individual particle detection and a substrate for viable cell-coating, i.e. the biological compartment. To date both compartments have been imaged sequentially in situ by confocal laser scanning microscopy (CLSM). This is yet in conflict with a functional read-out of the Cell-Fit-HD utilizing a fast live-cell imaging of the biological compartment with low phototoxicity on greater time scales. The read-out of the biological from the physical compartment was uncoupled. A read-out procedure was developed to image the cell layer by conventional widefield microscopy whereas the FNTD was imaged by CLSM. Point mapping registration of the confocal and widefield imaging data was performed. Non-fluorescent crystal defects (spinels) visible in both read-outs were used as control point pairs. The accuracy achieved was on the sub-µm scale. The read-out procedure by widefield microscopy does not impair the unique ability of spatial correlation by the Cell-Fit-HD. The uncoupling will enlarge the application potential of the hybrid technology significantly. The registration allows for an ultimate correlation of microscopic physical beam parameters and cell kinetics on greater time scales. The method reported herein will be instrumental for the introduction of a novel generation of compact detectors facilitating biodosimetric research towards high-throughput analysis.

  11. Radial distribution of dose within heavy charged particle tracks – Models and experimental verification using LiF:Mg,Cu,P TL detectors

    International Nuclear Information System (INIS)

    A new method of experimental verification of radial dose distribution models using solid state thermoluminescent (TL) detectors LiF:Mg,Cu,P has been recently proposed. In this work the method was applied to verify the spatial distribution of energy deposition within a single 131Xe ion track. Detectors were irradiated at the Department of Physics of the University of Jyväskylä, Finland. The obtained results have been compared with theoretical data, calculated according to the Zhang et al., Cucinotta et al. and Geiss et al. radial dose distribution (RDD) models. At the lowest dose range the Zhang et al. RDD model exhibited the best agreement as compared to experimental data. In the intermediate dose range, up to 104 Gy, the best agreement was found for the RDD model of Cucinotta et al. The probability of occurrence of doses higher than 104 Gy within a single 131Xe ion track was found to be lower than predicted by all the studied RDD models. This may be a result of diffusion of the charge, which is then captured by TL-related trapping sites, at the distances up to dozens of nanometers from the ionization site. - Highlights: • Innovative method of experimental verification of RDD models has been proposed. • The method was tested for 9.3 MeV/n 131Xe ions and three different RDD models. • Up to 104 Gy the analyzed models present good agreement with experimental data. • Probability of occurrence of doses >104 Gy within particle track is relatively low. • Newly proposed method gives results consistent with experimental data within 15%

  12. Asynchronous Parallel Evolutionary Algorithms for Constrained Optimizations

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Recently Guo Tao proposed a stochastic search algorithm in his PhD thesis for solving function op-timization problems. He combined the subspace search method (a general multi-parent recombination strategy) with the population hill-climbing method. The former keeps a global search for overall situation,and the latter keeps the convergence of the algorithm. Guo's algorithm has many advantages ,such as the sim-plicity of its structure ,the higher accuracy of its results, the wide range of its applications ,and the robustness of its use. In this paper a preliminary theoretical analysis of the algorithm is given and some numerical experiments has been done by using Guo's algorithm for demonstrating the theoretical results. Three asynchronous paral-lel evolutionary algorithms with different granularities for MIMD machines are designed by parallelizing Guo's Algorithm.

  13. 基于FCM聚类的粒子滤波多目标跟踪算法%Multi-target tracking algorithm based on FCM and particle filter

    Institute of Scientific and Technical Information of China (English)

    陈龙; 郭宝龙; 孙伟

    2011-01-01

    Divergence problem of similar targets and fixed window width of target kernel function are the defects existing in multiple-object tracking method. The new algorithm stated in this paper is based on classical particle filter theory. Firstly, variable ellipse is used as particle zone to gain the cluster center of each object through Mean-Shift algorithm after importance re-sampling. Then, FCM is used to complete particle clustering and get the particle subset of respective objects. Lastly, the final state of each target is calculated and the kernel window width is revised through particle subgroup. Experiments prove that this algorithm can solve the divergence problem of traditional particle filter, reduce number of particles, and has robustness and real-time property.%针对多目标跟踪中相似目标的发散问题和跟踪核函数窗宽固定的缺陷,提出一种基于FCM(fuzzy C-means)聚类的粒子滤波算法.该算法结合经典粒子滤波理论,使用可变椭圆作为粒子区域,在粒子滤波的重要性重采样后,通过Mean-Shift算法获得每个目标的聚类中心,使用FCM聚类算法完成粒子聚类,获得相应目标的粒子子群,最后通过粒子子群估计各目标的最终状态并修正核窗口宽度.实验表明,与传统粒子滤波算法相比,该算法解决了传统粒子滤波的发散问题,减少了粒子数量,能够准确地对多目标进行跟踪,具有很好的鲁棒性和实时性.

  14. Design and Study on Sliding Mode Extremum Seeking Control of the Chaos Embedded Particle Swarm Optimization for Maximum Power Point Tracking in Wind Power Systems

    Directory of Open Access Journals (Sweden)

    Jui-Ho Chen

    2014-03-01

    Full Text Available This paper proposes a sliding mode extremum seeking control (SMESC of chaos embedded particle swarm optimization (CEPSO Algorithm, applied to the design of maximum power point tracking in wind power systems. Its features are that the control parameters in SMESC are optimized by CEPSO, making it unnecessary to change the output power of different wind turbines, the designed in-repetition rate is reduced, and the system control efficiency is increased. The wind power system control is designed by simulation, in comparison with the traditional wind power control method, and the simulated dynamic response obtained by the SMESC algorithm proposed in this paper is better than the traditional hill-climbing search (HCS and extremum seeking control (ESC algorithms in the transient or steady states, validating the advantages and practicability of the method proposed in this paper.

  15. Energy deposition by a {sup 106}Ru/{sup 106}Rh eye applicator simulated using LEPTS, a low-energy particle track simulation

    Energy Technology Data Exchange (ETDEWEB)

    Fuss, M.C. [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas (CSIC), Serrano 113-bis, 28006 Madrid (Spain); Munoz, A.; Oller, J.C. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avenida Complutense 22, 28040 Madrid (Spain); Blanco, F. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, Avenida Complutense, 28040 Madrid (Spain); Williart, A. [Departamento de Fisica de los Materiales, Universidad Nacional de Educacion a Distancia, Senda del Rey 9, 28040 Madrid (Spain); Limao-Vieira, P. [Laboratorio de Colisoes Atomicas e Moleculares, Departamento de Fisica, CEFITEC, FCT-Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Caparica (Portugal); Borge, M.J.G.; Tengblad, O. [Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas (CSIC), Serrano 113-bis, 28006 Madrid (Spain); Huerga, C.; Tellez, M. [Hospital Universitario La Paz, Paseo de la Castellana 261, 28046 Madrid (Spain); Garcia, G., E-mail: g.garcia@iff.csic.es [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas (CSIC), Serrano 113-bis, 28006 Madrid (Spain); Departamento de Fisica de los Materiales, Universidad Nacional de Educacion a Distancia, Senda del Rey 9, 28040 Madrid (Spain)

    2011-09-15

    The present study introduces LEPTS, an event-by-event Monte Carlo programme, for simulating an ophthalmic {sup 106}Ru/{sup 106}Rh applicator relevant in brachytherapy of ocular tumours. The distinctive characteristics of this code are the underlying radiation-matter interaction models that distinguish elastic and several kinds of inelastic collisions, as well as the use of mostly experimental input data. Special emphasis is placed on the treatment of low-energy electrons for generally being responsible for the deposition of a large portion of the total energy imparted to matter. - Highlights: > We present the Monte Carlo code LEPTS, a low-energy particle track simulation. > Carefully selected input data from 10 keV to 1 eV. > Application to an electron emitting Ru-106/Rh-106 plaque used in brachytherapy.

  16. Visualization of the flow profile inside a thinning filament during capillary breakup of a polymer solution via particle image velocimetry (PIV) and particle tracking velocimetry (PTV)

    CERN Document Server

    Gier, S

    2012-01-01

    We investigated the flow profile of a polymer solution in a thinning capillary bridge. Fluorescent tracer particles with a diameter of 3$\\mu$m were used to visualize the flow. The cylindrical shape of the filament introduced strong optical abberations that could be corrected for, and we were able to characterize the flow in filaments with a thickness ranging from 150 to 30 $\\mu$m. In the first regime when the filament was still sufficiently large, we used a PIV algorithm to deduce the flow field. At later stages when the number of particles in the observation plane decreased a PTV algorithm was used. The main two results of our measurements are as follows. First, the flow profile at the formation of the cylindrical filament is highly inhomogeneous and there is only flow in the outer parts of the filament. Second, we find that in most parts of the regime, where the temporal radius of the thinning filament can be fitted with an exponential law the flow indeed is purely extensional.

  17. The track structures of ionizing particles and their application to radiation biophysics. I. A new analytical method for investigating two biophysical models

    International Nuclear Information System (INIS)

    A new approach to the interpretation of the effects of radiation on cells is described, in which sample particle tracks are constructed using a Monte Carlo computer program and the exposure of cellular targets to these tracks is simulated using a second program known as BIOPHYS. Data on the shapes and DNA contents of the cell nuclei are obtained from the literature. It is assumed that the sensitive material is DNA, and that the target is divided into cubes of approximately 2 nm (the diameter of the DNA helix) per side; the numbers of these cubes containing different numbers of ionizations are derived. Two different methods of analysing the output of BIOPHYS are described. In the first, it is assumed that lethality is caused by the occurrence of a number of ionizations equal to or greater than a certain threshold in one cube; in the second method, it is assumed that only two ionizations are required, in different parts of the cube, but that only some fraction of the cube is sensitive. These models have been applied to the interpretation of the variation of radiosensitivity with a linear energy transfer (LET) of spores of Bacillus subtilis exposed wet and dry, and good fits to the published experimental data were obtained using both models. Fits to experimental data for a range of other cell lines will be presented in a second paper. (orig.)

  18. 基于粒子滤波的无人机协同跟踪算法%Study on Cooperative Tracking Algorithm Based on Particle Filter for UAVs

    Institute of Scientific and Technical Information of China (English)

    姜肖英; 姚敏; 赵敏

    2012-01-01

    针对无人机群协同跟踪移动目标问题展开研究.由于传感器测量精度的有限性,采用多架无人机合作来获得多个测量值,再根据数据融合的方法获得较精确的测量值;建立了移动目标的模型,结合测量值应用粒子滤波算法来预测目标的状态.仿真结果表明了该算法能使无人机获得较好的跟踪效果.%This paper investigates the cooperative tracking a moving target by using unmanned aerial vehicles(UAV) . Because of the limited nature of the sensor accuracy, it uses Establishing multi-UAV to obtain multiple measurements, according to data fusion method to obtain more accurate measurements. A model of a moving target, then using particle filter to predict the target state is established. The results of the simulation tests prove that this method can keep tracking the moving targets well for UAV.

  19. Radiation effects in the polycarbonate of bisphenol-A. Thermoluminescence electron spin resonance and charged particle track studies

    International Nuclear Information System (INIS)

    A detailed investigation is presented of the thermoluminescence observable above room temperature from the polycarbonate of bisphenol-A after its exposure to different radiations. A correlation study is described by which features of the complex thermoluminescence glow curve from a commercial grade of the polycarbonate of bisphenol-A are related to the etchability of charged particle damage trails and the radiogenic ESR signal. A model is presented whereby the etchability of charged particle damage trails is associated with chain scission caused by the high local dose of radiation in the vicinity of the trajectories of charged particles. Methods by which activation constants controlling the thermoluminescence glow curve can be evaluated are discussed and results are presented. It is concluded that glow peaks associated with the ESR signal or enhanced etchability are related to small-scale motions in the molecular matrix of the polycarbonate of bisphenol-A. These motions are thermally activated in accord with the simple Boltzmann relation usually incorporated into theories of thermoluminescence. Another component glow peak of the thermoluminescence glow curve is shown to be associated with the glass-rubber transition in the polycarbonate of bisphenol-A. Different features of the thermoluminescence glow curve can be related to relaxations of the polymer matrix and decomposition of the matrix. It is confirmed that the dominant bulk effect of radiation in the polycarbonate of bisphenol-A exposed to large doses of radiation is chain scission. (author)

  20. Tracking objects, Tracking agents

    OpenAIRE

    Bullot, Nicolas J.; Rysiew, Patrick

    2005-01-01

    Animals and humans have to keep track of individuals in their environment, both in perception (sensorimotor tracking) and in cognition (e.g., spatio-temporal localization and linguistic reference via memory, communication and reasoning). Items that are typical targets for tracking are things such as stationary physical objects (e.g., rocks, plants, trees, buildings, or attached artifacts), moving physical objects (e.g., animals, certain artifacts) and human beings. All such items are located ...

  1. Contribution of various microenvironments to the daily personal exposure to ultrafine particles: Personal monitoring coupled with GPS tracking

    Science.gov (United States)

    Bekö, Gabriel; Kjeldsen, Birthe Uldahl; Olsen, Yulia; Schipperijn, Jasper; Wierzbicka, Aneta; Karottki, Dorina Gabriela; Toftum, Jørn; Loft, Steffen; Clausen, Geo

    2015-06-01

    Exposure to ultrafine particles (UFP) may have adverse health effects. Central monitoring stations do not represent the personal exposure to UFP accurately. Few studies have previously focused on personal exposure to UFP. Sixty non-smoking residents living in Copenhagen, Denmark were asked to carry a backpack equipped with a portable monitor, continuously recording particle number concentrations (PN), in order to measure the real-time individual exposure over a period of ∼48 h. A GPS logger was carried along with the particle monitor and allowed us to estimate the contribution of UFP exposure occurring in various microenvironments (residence, during active and passive transport, other indoor and outdoor environments) to the total daily exposure. On average, the fractional contribution of each microenvironment to the daily integrated personal exposure roughly corresponded to the fractions of the day the subjects spent in each microenvironment. The home environment accounted for 50% of the daily personal exposure. Indoor environments other than home or vehicles contributed with ∼40%. The highest median UFP concentration was obtained during passive transport (vehicles). However, being in transit or outdoors contributed 5% or less to the daily exposure. Additionally, the subjects recorded in a diary the periods when they were at home. With this approach, 66% of the total daily exposure was attributable to the home environment. The subjects spent 28% more time at home according to the diary, compared to the GPS. These results may indicate limitations of using diaries, but also possible inaccuracy and miss-classification in the GPS data.

  2. A novel position and time sensing active pixel sensor with field-assisted electron collection for charged particle tracking and electron microscopy

    Science.gov (United States)

    De Geronimo, G.; Deptuch, G.; Dragone, A.; Radeka, V.; Rehak, P.; Castoldi, A.; Fazzi, A.; Gatti, E.; Guazzoni, C.; Rijssenbeek, M.; Dulinski, W.; Besson, A.; Deveaux, M.; Winter, M.

    2006-11-01

    A new type of active pixel sensors (APSs) to track charged particles for particle physics experiments or to count number of electrons that cross any pixel at the focal plane of electron microscopes is described. The electric field of desirable shape is created inside the active volume of the pixel introducing the drift component in the movement of the signal electrons towards charge collecting electrodes. The electric field results from the flow of ˜100 mA/cm 2 hole currents within individual pixels of the sensor. The proposed sensor is produced using a standard industrially available complementary metal oxide silicon (CMOS) process. There are two main advantages of the proposed detectors when compared to the present (February 2005) state-of-the-art, i.e. field-free APS sensors. The first advantage of a field-assisted transport mechanism is the reduction of the charge collection time and of the sharing of the signal electrons between adjacent pixels by diffusion. The second advantage is the freedom to use both kinds of MOS transistors within each pixel of the sensor. Thus, the full functional power of CMOS circuits can be embedded in situ. As an example, 16-bit scalers will be implemented in each pixel of the sensor for electron microscopy. The reduced collection time combined with the state-of-the-art electronics within each pixel provides the most complete information about the position and the timing of incident charged particles for particle physics experiments. Position resolution of new sensors was computationally simulated to be a few microns, that is, the same as the resolution of standard APSs. Moreover, the active depth of the sensor and the associate electronics is less than about 20 μm and a thinned down sensor together with its beryllium backing can have a total thickness of less than 0.1% of one radiation length. The reduction of the thickness of the detector reduces the amount of multiple scattering within the detector. The determination of the

  3. A search for new heavy particles in events with highly ionising, short tracks at the CMS experiment

    CERN Document Server

    Lenz, Teresa; Schleper, Peter

    2016-01-01

    The main focus of the CMS experiment at the Large Hadron Collider (LHC) is to search for physics beyond the Standard Model and to measure Standard Model parameters. For both purposes it is essential to determine important performance parameters of the CMS detector. The here presented thesis contributes in a twofold way to the physics program of CMS. In the first part of this thesis, a search for physics beyond the Standard Model is presented. It is motivated by supersymmetric models with nearly mass-degenerate lightest neutralinos and lightest charginos. The small mass gap between chargino and neutralino can lead to long lifetimes of the chargino due to phase space suppression. Thus, the chargino can reach the tracking system before its decay. The here presented search targets chargino lifetimes of $\\text{c}\\tau \\approx 1 - 30\\,\\text{cm}$ where most of the charginos decay in the first layers of the tracker. This search aims at increasing the search sensitivity of existing searches with respect to these models...

  4. A test beam setup for the characterization of the Geiger-mode avalanche photodiode technology for particle tracking

    Energy Technology Data Exchange (ETDEWEB)

    Vilella, E., E-mail: evilella@el.ub.es [Department of Electronics, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain); Alonso, O. [Department of Electronics, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain); Trenado, J. [Department of Structure and Constituents of Matter, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain); Vila, A.; Casanova, R. [Department of Electronics, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain); Vos, M. [Instituto de Fisica Corpuscular (IFIC), C/Catedratico Jose Beltran 2, 46980 Paterna (Spain); Garrido, L. [Department of Structure and Constituents of Matter, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain); Dieguez, A. [Department of Electronics, University of Barcelona (UB), C/Marti i Franques 1, 08028 Barcelona (Spain)

    2012-12-01

    It is well known that avalanche photodiodes operated in the Geiger mode above the breakdown voltage offer a virtually infinite gain and time accuracy in the picosecond range that can be used for single photon detection. However, their performance in particle detection still remains unexplored. In this contribution, we are going to expose different steps that we have taken in order to prove the efficiency of the Geiger mode avalanche photodiodes in the aforementioned field. In particular, we will present a setup for the characterization of these sensors in a test beam. The expected results of the test beam at DESY and CERN have been simulated with Geant4 and will also be exposed. -- Highlights: Black-Right-Pointing-Pointer A Setup for characterization of the GAPD technology in a test beam is presented. Black-Right-Pointing-Pointer Two test beams at DESY (6 GeV) and CERN (120 GeV) are already planned at current time. Black-Right-Pointing-Pointer A GAPD array has been designed and fabricated to fit the test beam requirements. Black-Right-Pointing-Pointer We have prepared a test beam setup to minimize the particle multiscattering. Black-Right-Pointing-Pointer The Expected results at DESY and CERN have been simulated with Geant4.

  5. Optimum Multiuser Detector for Multipath Slow Fading Asynchronous CDMA Channels

    Institute of Scientific and Technical Information of China (English)

    WangZhaocheng; YangZhixing; 等

    1995-01-01

    A structure of optimum multiuser detector for asynchronous CDMA in multipath slow fading channels is derived and the significant performance gain over the conventional RAKE receiv-er is shown by simulation.

  6. Current Trends in High-Level Synthesis of Asynchronous Circuits

    DEFF Research Database (Denmark)

    Sparsø, Jens

    2009-01-01

    This paper is a survey paper presenting what the author sees as two major and promising trends in the current research in CAD-tools and design-methods for asynchronous circuits. One branch of research builds on top of existing asynchronous CAD-tools that perform syntax directed translation, e.......g. the Haste/TiDE tool from Handshake Solutions or the Balsa tool from the University of Manchester. The aims are to add highlevel synthesis capabilities to these tools and to extend the tools such that a wider range of (higher speed) micro-architectures can be generated. Another branch of research takes...... a conventional synchronous circuit as the starting point, and then adds some form of handshake-based flow-control. One approach keeps the global clock and implements discrete-time asynchronous operation. Another approach substitutes the clocked registers by asynchronous handshake-registers, thus creating truly...

  7. TCDQ-TCT retraction and losses during asynchronous beam dump

    CERN Document Server

    Bracco, Chiara; Quaranta, Elena; CERN. Geneva. ATS Department

    2016-01-01

    The protection provided by the TCDQs in case of asynchronous beam dump depends strongly on their correct setup. They have to respect the strict hierarchy of the full collimation system and shield the tertiary collimators in the experimental regions. This MD aimed at performing asynchronous beam dump tests with different configurations, in order to assess the minimum allowed retraction between TCTs and TCDQs and, as a consequence, on the The protection provided by the TCDQs in case of asynchronous beam dump depends strongly on their correct setup. They have to respect the strict hierarchy of the full collimation system and shield the tertiary collimators in the experimental regions. This MD aimed at performing asynchronous beam dump tests with different configurations, in order to assess the minimum allowed retraction between TCTs and TCDQs and, as a consequence, on the β* reach.

  8. Asynchronous FSK wireless data traffic interface circuit design

    International Nuclear Information System (INIS)

    This article gives a practical interface circuit, which is able to conduct asynchronous wireless data communication through data transfer broadcasting station. And the circuit's design as well as its applications are introduced. (authors)

  9. Stand-Alone and Hybrid Positioning Using Asynchronous Pseudolites

    Directory of Open Access Journals (Sweden)

    Ciro Gioia

    2014-12-01

    Full Text Available global navigation satellite system (GNSS receivers are usually unable to achieve satisfactory performance in difficult environments, such as open-pit mines, urban canyons and indoors. Pseudolites have the potential to extend GNSS usage and significantly improve receiver performance in such environments by providing additional navigation signals. This also applies to asynchronous pseudolite systems, where different pseudolites operate in an independent way. Asynchronous pseudolite systems require, however, dedicated strategies in order to properly integrate GNSS and pseudolite measurements. In this paper, several asynchronous pseudolite/GNSS integration strategies are considered: loosely- and tightly-coupled approaches are developed and combined with pseudolite proximity and receiver signal strength (RSS-based positioning. The performance of the approaches proposed has been tested in different scenarios, including static and kinematic conditions. The tests performed demonstrate that the methods developed are effective techniques for integrating heterogeneous measurements from different sources, such as asynchronous pseudolites and GNSS.

  10. Solving SAT and Hamiltonian Cycle Problem Using Asynchronous P Systems

    Science.gov (United States)

    Tagawa, Hirofumi; Fujiwara, Akihiro

    In the present paper, we consider fully asynchronous parallelism in membrane computing, and propose two asynchronous P systems for the satisfiability (SAT) and Hamiltonian cycle problem. We first propose an asynchronous P system that solves SAT with n variables and m clauses, and show that the proposed P system computes SAT in O(mn2n) sequential steps or O(mn) parallel steps using O(mn) kinds of objects. We next propose an asynchronous P system that solves the Hamiltonian cycle problem with n nodes, and show that the proposed P system computes the problem in O(n!) sequential steps or O(n2) parallel steps using O(n2) kinds of objects.

  11. A proof system for asynchronously communicating deterministic processes

    NARCIS (Netherlands)

    de Boer, F.S.; van Hulst, M.

    1994-01-01

    We introduce in this paper new communication and synchronization constructs which allow deterministic processes, communicating asynchronously via unbounded FIFO buffers, to cope with an indeterminate environment. We develop for the resulting parallel programming language, which subsumes deterministi

  12. Novel Asynchronous Wrapper and Its Application to GALS Systems

    Institute of Scientific and Technical Information of China (English)

    Zhuang Shengxian; Peng Anjin; Lars Wanhammar

    2006-01-01

    An asynchronous wrapper with novel handshake circuits for data communication in globally asynchronous locally synchronous (GALS) systems is proposed. The handshake circuits include two communication ports and a local clock generator. Two approaches for the implementation of communication ports are presented, one with pure standard cells and the others with Müller-C elements. The detailed design methodology for GALS systems is given and the circuits are validated with VHDL and circuits simulation in standard CMOS technology.

  13. Reasoning on Robot Knowledge from Discrete and Asynchronous Observations

    OpenAIRE

    Ziafati, Pouyan; Elrakaiby, Yehia; Torre, Leon van der; Voos, Holger; dastani, mehdi; Meyer, John-Jules; Van Zee, Marc

    2014-01-01

    Robot knowledge of the world is created from discrete and asynchronous events received from its perception components. Proper representation and maintenance of robot knowledge is crucial to enable the use of robot knowledge for planning, user-interaction, etc. This paper identifies some of the main issues related to the representation, maintenance and querying of robot knowledge based on discrete asynchronous events such as event-history management and synchronization, and introduces a langua...

  14. A test beam set-up for the characterization of the Geiger-mode avalanche photodiode technology for particle tracking

    CERN Document Server

    Vilella, A; Trenado, J; Vila, A; Casanova, R; Vos, M; Garrido, L; Dieguez, A

    2012-01-01

    It is well known that avalanche photodiodes operated in the Geiger mode above the breakdown voltage offer a virtually infinite gain and time accuracy in the picosecond range that can be used for single photon detection. However, their performance in particle detection still remains unexplored. In this contribution, we are going to expose different steps that we have taken in order to prove the efficiency of the Geiger mode avalanche photodiodes in the aforementioned field. In particular, we will present a setup for the characterization of these sensors in a test beam. The expected results of the test beam at DESY and CERN have been simulated with Geant4 and will also be exposed.

  15. Development of new techniques for three dimensional tracking of charged particles for possible applications in the search for neutrinoless double beta decay

    International Nuclear Information System (INIS)

    Since its prediction in 1937, several generations of experimental physicists have tried to confirm the neutrinoless double beta decay. An observation would have fundamental consequences for the understanding of particle physics. However, the experimental requirements are very demanding wherefore the race is still ongoing between many collaborations. The main challenge in this field is the reduction of background. Any decay in the natural decay chain is orders of magnitude more likely than the neutrinoless double beta decay. The half-life of this decay is known to be longer than 1025 years. Therefore, any detector will see a vast majority of events which are not signal events. Such events have to be identified and rejected. Primarily, this is done by measuring the kinetic energy of the decay products but also the trajectory of the particles resulting from the decay can be used for identification. Within the scope of this thesis different techniques were developed and tested which can be used to record such trajectories. It was shown that trajectories can be used indeed to identify and distinguish different types of events. The hybrid semiconductor detector named Timepix was used to record two-dimensional tracks of Compton-scattered electrons and electron-positron pairs in a 1mm thick cadmium-telluride sensor layer. Artificial neural networks could successfully be employed to distinguish both event types. Furthermore, a ''proof-of-principle'' experiment was successfully performed where three dimensional trajectories of high energetic electrons could be reconstructed from data recorded with a similar Timepix detector. Also, a new concept, where three dimensional trajectories of ionizing particles are imaged by scintillation light, was developed and successfully tested. In a ''proof-of-principle'' experiment three dimensional trajectories of high energetic electrons through a scintillator were reconstructed from data taken with a

  16. MODIFIED MICROPIPLINE ARCHITECTURE FOR SYNTHESIZABLE ASYNCHRONOUS FIR FILTER DESIGN

    Directory of Open Access Journals (Sweden)

    Basel Halak

    2016-02-01

    Full Text Available The use of asynchronous design approaches to construct digital signal processing (DSP systems is a rapidly growing research area driven by a wide range of emerging energy constrained applications such as wireless sensor network, portable medical devices and brain implants. The asynchronous design techniques allow the construction of systems which are samples driven, which means they only dissipate dynamic energy when there processing data and idle otherwise. This inherent advantage of asynchronous design over conventional synchronous circuits allows them to be energy efficient. However the implementation flow of asynchronous systems is still difficult due to its lack of compatibility with industrystandard synchronous design tools and modelling languages. This paper devises a novel asynchronous design for a finite impulse response (FIR filter, an essential building block of DSP systems, which is synthesizable and suitable for implementation using conventional synchronous systems design flow and tools. The proposed design is based on a modified version of the micropipline architecture and it is constructed using four phase bundled data protocol. A hardware prototype of the proposed filter has been developed on an FPGA, and systematically verified. The results prove correct functionality of the novel design and a superior performance compared to a synchronous FIR implementation. The findings of this work will allow a wider adoption of asynchronous circuits by DSP designers to harness their energy and performance benefits.

  17. Building asynchronous geospatial processing workflows with web services

    Science.gov (United States)

    Zhao, Peisheng; Di, Liping; Yu, Genong

    2012-02-01

    Geoscience research and applications often involve a geospatial processing workflow. This workflow includes a sequence of operations that use a variety of tools to collect, translate, and analyze distributed heterogeneous geospatial data. Asynchronous mechanisms, by which clients initiate a request and then resume their processing without waiting for a response, are very useful for complicated workflows that take a long time to run. Geospatial contents and capabilities are increasingly becoming available online as interoperable Web services. This online availability significantly enhances the ability to use Web service chains to build distributed geospatial processing workflows. This paper focuses on how to orchestrate Web services for implementing asynchronous geospatial processing workflows. The theoretical bases for asynchronous Web services and workflows, including asynchrony patterns and message transmission, are examined to explore different asynchronous approaches to and architecture of workflow code for the support of asynchronous behavior. A sample geospatial processing workflow, issued by the Open Geospatial Consortium (OGC) Web Service, Phase 6 (OWS-6), is provided to illustrate the implementation of asynchronous geospatial processing workflows and the challenges in using Web Services Business Process Execution Language (WS-BPEL) to develop them.

  18. Ternary Tree Asynchronous Interconnect Network for GALS' SOC

    Directory of Open Access Journals (Sweden)

    Vivek E. Khetade

    2013-03-01

    Full Text Available Interconnect fabric requires easy integration of computational block operating with unrelated clocks.Thispaper presents asynchronous interconnect with ternary tree asynchronous network for GloballyAsynchronous Locally Synchronous (GALS system-on-chip (SOC. Here architecture is proposed forinterconnection with ternary tree asynchronous network where ratio of number NOC design unit andnumber of router is 4:1,6:2, 8:3,10:4 etc .It is scalable for any number of NOC design unit. It offersaneasy integration of different clock domain with lowcommunication overhead .NOC design unit for GALS‘SOC is formulated by wrapping synchronous module with input port along with input port controller,output port along with output port controller and local clock generator. It creates the interface betweensynchronous to asynchronous and asynchronous to synchronous. For this purpose four port asynchronousrouters is designed with routing element and outputarbitration and buffering with micro-pipeline. Thisinterconnect fabric minimizes silicon area, minimize Latency and maximize throughput. Here functionalmodel is made for TTAN and application MPEG4 is mapped on the Network .Desired traffic pattern isgenerated and performance of the network is evaluated. Significant improvement in the networkperformance parameter has been observed.

  19. Magnetic Particle / Magnetic Resonance Imaging: In-Vitro MPI-Guided Real Time Catheter Tracking and 4D Angioplasty Using a Road Map and Blood Pool Tracer Approach

    Science.gov (United States)

    Jung, Caroline; Kaul, Michael Gerhard; Werner, Franziska; Them, Kolja; Reimer, Rudolph; Nielsen, Peter; vom Scheidt, Annika; Adam, Gerhard; Knopp, Tobias; Ittrich, Harald

    2016-01-01

    Purpose In-vitro evaluation of the feasibility of 4D real time tracking of endovascular devices and stenosis treatment with a magnetic particle imaging (MPI) / magnetic resonance imaging (MRI) road map approach and an MPI-guided approach using a blood pool tracer. Materials and Methods A guide wire and angioplasty-catheter were labeled with a thin layer of magnetic lacquer. For real time MPI a custom made software framework was developed. A stenotic vessel phantom filled with saline or superparamagnetic iron oxide nanoparticles (MM4) was equipped with bimodal fiducial markers for co-registration in preclinical 7T MRI and MPI. In-vitro angioplasty was performed inflating the balloon with saline or MM4. MPI data were acquired using a field of view of 37.3×37.3×18.6 mm3 and a frame rate of 46 volumes/sec. Analysis of the magnetic lacquer-marks on the devices were performed with electron microscopy, atomic absorption spectrometry and micro-computed tomography. Results Magnetic marks allowed for MPI/MRI guidance of interventional devices. Bimodal fiducial markers enable MPI/MRI image fusion for MRI based roadmapping. MRI roadmapping and the blood pool tracer approach facilitate MPI real time monitoring of in-vitro angioplasty. Successful angioplasty was verified with MPI and MRI. Magnetic marks consist of micrometer sized ferromagnetic plates mainly composed of iron and iron oxide. Conclusions 4D real time MP imaging, tracking and guiding of endovascular instruments and in-vitro angioplasty is feasible. In addition to an approach that requires a blood pool tracer, MRI based roadmapping might emerge as a promising tool for radiation free 4D MPI-guided interventions. PMID:27249022

  20. Magnetic Particle / Magnetic Resonance Imaging: In-Vitro MPI-Guided Real Time Catheter Tracking and 4D Angioplasty Using a Road Map and Blood Pool Tracer Approach.

    Directory of Open Access Journals (Sweden)

    Johannes Salamon

    Full Text Available In-vitro evaluation of the feasibility of 4D real time tracking of endovascular devices and stenosis treatment with a magnetic particle imaging (MPI / magnetic resonance imaging (MRI road map approach and an MPI-guided approach using a blood pool tracer.A guide wire and angioplasty-catheter were labeled with a thin layer of magnetic lacquer. For real time MPI a custom made software framework was developed. A stenotic vessel phantom filled with saline or superparamagnetic iron oxide nanoparticles (MM4 was equipped with bimodal fiducial markers for co-registration in preclinical 7T MRI and MPI. In-vitro angioplasty was performed inflating the balloon with saline or MM4. MPI data were acquired using a field of view of 37.3×37.3×18.6 mm3 and a frame rate of 46 volumes/sec. Analysis of the magnetic lacquer-marks on the devices were performed with electron microscopy, atomic absorption spectrometry and micro-computed tomography.Magnetic marks allowed for MPI/MRI guidance of interventional devices. Bimodal fiducial markers enable MPI/MRI image fusion for MRI based roadmapping. MRI roadmapping and the blood pool tracer approach facilitate MPI real time monitoring of in-vitro angioplasty. Successful angioplasty was verified with MPI and MRI. Magnetic marks consist of micrometer sized ferromagnetic plates mainly composed of iron and iron oxide.4D real time MP imaging, tracking and guiding of endovascular instruments and in-vitro angioplasty is feasible. In addition to an approach that requires a blood pool tracer, MRI based roadmapping might emerge as a promising tool for radiation free 4D MPI-guided interventions.

  1. Managing Asynchronous Data in ATLAS's Concurrent Framework

    CERN Document Server

    Leggett, Charles; The ATLAS collaboration

    2016-01-01

    In order to be able to make effective use of emerging hardware, where the amount of memory available to any CPU is rapidly decreasing as the core count continues to rise, ATLAS has begun a migration to a concurrent, multi-threaded software framework, known as AthenaMT. Significant progress has been made in implementing AthenaMT - we can currently run realistic Geant4 simulations on massively concurrent machines. the migration of realistic prototypes of reconstruction workflows is more difficult, given the large amounts of legacy code and the complexity and challenges of reconstruction software. These types of workflows, however, are the types that will most benefit from the memory reduction features of a multi-threaded framework. One of the challenges that we will report on in this paper is the re-design and implementation of several key asynchronous technologies whose behaviour is radically different in a concurrent environment than in a serial one, namely the management of Conditions data and the Detector D...

  2. Asynchronous Rate Chaos in Spiking Neuronal Circuits

    Science.gov (United States)

    Harish, Omri; Hansel, David

    2015-01-01

    The brain exhibits temporally complex patterns of activity with features similar to those of chaotic systems. Theoretical studies over the last twenty years have described various computational advantages for such regimes in neuronal systems. Nevertheless, it still remains unclear whether chaos requires specific cellular properties or network architectures, or whether it is a generic property of neuronal circuits. We investigate the dynamics of networks of excitatory-inhibitory (EI) spiking neurons with random sparse connectivity operating in the regime of balance of excitation and inhibition. Combining Dynamical Mean-Field Theory with numerical simulations, we show that chaotic, asynchronous firing rate fluctuations emerge generically for sufficiently strong synapses. Two different mechanisms can lead to these chaotic fluctuations. One mechanism relies on slow I-I inhibition which gives rise to slow subthreshold voltage and rate fluctuations. The decorrelation time of these fluctuations is proportional to the time constant of the inhibition. The second mechanism relies on the recurrent E-I-E feedback loop. It requires slow excitation but the inhibition can be fast. In the corresponding dynamical regime all neurons exhibit rate fluctuations on the time scale of the excitation. Another feature of this regime is that the population-averaged firing rate is substantially smaller in the excitatory population than in the inhibitory population. This is not necessarily the case in the I-I mechanism. Finally, we discuss the neurophysiological and computational significance of our results. PMID:26230679

  3. Rapid, generalized adaptation to asynchronous audiovisual speech.

    Science.gov (United States)

    Van der Burg, Erik; Goodbourn, Patrick T

    2015-04-01

    The brain is adaptive. The speed of propagation through air, and of low-level sensory processing, differs markedly between auditory and visual stimuli; yet the brain can adapt to compensate for the resulting cross-modal delays. Studies investigating temporal recalibration to audiovisual speech have used prolonged adaptation procedures, suggesting that adaptation is sluggish. Here, we show that adaptation to asynchronous audiovisual speech occurs rapidly. Participants viewed a brief clip of an actor pronouncing a single syllable. The voice was either advanced or delayed relative to the corresponding lip movements, and participants were asked to make a synchrony judgement. Although we did not use an explicit adaptation procedure, we demonstrate rapid recalibration based on a single audiovisual event. We find that the point of subjective simultaneity on each trial is highly contingent upon the modality order of the preceding trial. We find compelling evidence that rapid recalibration generalizes across different stimuli, and different actors. Finally, we demonstrate that rapid recalibration occurs even when auditory and visual events clearly belong to different actors. These results suggest that rapid temporal recalibration to audiovisual speech is primarily mediated by basic temporal factors, rather than higher-order factors such as perceived simultaneity and source identity.

  4. Insights into cell membrane microdomain organization from live cell single particle tracking of the IgE high affinity receptor FcϵRI of mast cells.

    Science.gov (United States)

    Espinoza, Flor A; Wester, Michael J; Oliver, Janet M; Wilson, Bridget S; Andrews, Nicholas L; Lidke, Diane S; Steinberg, Stanly L

    2012-08-01

    Current models propose that the plasma membrane of animal cells is composed of heterogeneous and dynamic microdomains known variously as cytoskeletal corrals, lipid rafts and protein islands. Much of the experimental evidence for these membrane compartments is indirect. Recently, live cell single particle tracking studies using quantum dot-labeled IgE bound to its high affinity receptor FcϵRI, provided direct evidence for the confinement of receptors within micrometer-scale cytoskeletal corrals. In this study, we show that an innovative time-series analysis of single particle tracking data for the high affinity IgE receptor, FcϵRI, on mast cells provides substantial quantitative information about the submicrometer organization of the membrane. The analysis focuses on the probability distribution function of the lengths of the jumps in the positions of the quantum dots labeling individual IgE FcϵRI complexes between frames in movies of their motion. Our results demonstrate the presence, within the micrometer-scale cytoskeletal corrals, of smaller subdomains that provide an additional level of receptor confinement. There is no characteristic size for these subdomains; their size varies smoothly from a few tens of nanometers to a over a hundred nanometers. In QD-IGE labeled unstimulated cells, jumps of less than 70 nm predominate over longer jumps. Addition of multivalent antigen to crosslink the QD-IgE-FcϵRI complexes causes a rapid slowing of receptor motion followed by a long tail of mostly jumps less than 70 nm. The reduced receptor mobility likely reflects both the membrane heterogeneity revealed by the confined motion of the monomeric receptor complexes and the antigen-induced cross linking of these complexes into dimers and higher oligomers. In both cases, the probability distribution of the jump lengths is well fit, from 10 nm to over 100 nm, by a novel power law. The fit for short jumps suggests that the motion of the quantum dots can be modeled as

  5. ASCERTAINMENT OF THE EQUIVALENT CIRCUIT PARAMETERS OF THE ASYNCHRONOUS MACHINE

    Directory of Open Access Journals (Sweden)

    V. S. Safaryan

    2015-01-01

    Full Text Available The article considers experimental and analytical determination of the asynchronous machine equivalent-circuit parameters with application of the reference data. Transient processes investigation of the asynchronous machines necessitates the equivalent circuit parameters (resistance impedance, inductances and coefficient of the stator-rotor contours mutual inductance that help form the transitory-process mathematical simulation model. The reference books do not provide those parameters; they instead give the rated ones (active power, voltage, slide, coefficient of performance and capacity coefficient as well as the ratio of starting and nominal currents and torques. The noted studies on the asynchronous machine equivalent-circuits parametrization fail to solve the problems ad finem or solve them with admissions. The paper presents experimental and analytical determinations of the asynchronous machine equivalent-circuit parameters: the experimental one based on the results of two measurements and the analytical one where the problem boils down to solving a system of nonlineal algebraic equations. The authors investigate the equivalent asynchronous machine input-resistance properties and adduce the dependence curvatures of the input-resistances on the slide. They present a symbolic model for analytical parameterization of the asynchronous machine equivalent-circuit that represents a system of nonlineal equations and requires one of the rotor-parameters arbitrary assignment. The article demonstrates that for the asynchronous machine equivalent-circuit experimental parameterization the measures are to be conducted of the stator-circuit voltage, current and active power with two different slides and arbitrary assignment of one of the rotor parameters. The paper substantiates the fact that additional measurement does not discard the rotor-parameter choice arbitrariness. The authors establish that in motoring mode there is a critical slide by which the

  6. Effect of asynchronous updating on the stability of cellular automata

    International Nuclear Information System (INIS)

    Highlights: ► An upper bound on the Lyapunov exponent of asynchronously updated CA is established. ► The employed update method has repercussions on the stability of CAs. ► A decision on the employed update method should be taken with care. ► Substantial discrepancies arise between synchronously and asynchronously updated CA. ► Discrepancies between different asynchronous update schemes are less pronounced. - Abstract: Although cellular automata (CAs) were conceptualized as utter discrete mathematical models in which the states of all their spatial entities are updated simultaneously at every consecutive time step, i.e. synchronously, various CA-based models that rely on so-called asynchronous update methods have been constructed in order to overcome the limitations that are tied up with the classical way of evolving CAs. So far, only a few researchers have addressed the consequences of this way of updating on the evolved spatio-temporal patterns, and the reachable stationary states. In this paper, we exploit Lyapunov exponents to determine to what extent the stability of the rules within a family of totalistic CAs is affected by the underlying update method. For that purpose, we derive an upper bound on the maximum Lyapunov exponent of asynchronously iterated CAs, and show its validity, after which we present a comparative study between the Lyapunov exponents obtained for five different update methods, namely one synchronous method and four well-established asynchronous methods. It is found that the stability of CAs is seriously affected if one of the latter methods is employed, whereas the discrepancies arising between the different asynchronous methods are far less pronounced and, finally, we discuss the repercussions of our findings on the development of CA-based models.

  7. Asynchronous vegetation phenology enhances winter body condition of a large mobile herbivore.

    Science.gov (United States)

    Searle, Kate R; Rice, Mindy B; Anderson, Charles R; Bishop, Chad; Hobbs, N T

    2015-10-01

    Understanding how spatial and temporal heterogeneity influence ecological processes forms a central challenge in ecology. Individual responses to heterogeneity shape population dynamics, therefore understanding these responses is central to sustainable population management. Emerging evidence has shown that herbivores track heterogeneity in nutritional quality of vegetation by responding to phenological differences in plants. We quantified the benefits mule deer (Odocoileus hemionus) accrue from accessing habitats with asynchronous plant phenology in northwest Colorado over 3 years. Our analysis examined both the direct physiological and indirect environmental effects of weather and vegetation phenology on mule deer winter body condition. We identified several important effects of annual weather patterns and topographical variables on vegetation phenology in the home ranges of mule deer. Crucially, temporal patterns of vegetation phenology were linked with differences in body condition, with deer tending to show poorer body condition in areas with less asynchronous vegetation green-up and later vegetation onset. The direct physiological effect of previous winter precipitation on mule deer body condition was much less important than the indirect effect mediated by vegetation phenology. Additionally, the influence of vegetation phenology on body fat was much stronger than that of overall vegetation productivity. In summary, changing annual weather patterns, particularly in relation to seasonal precipitation, have the potential to alter body condition of this important ungulate species during the critical winter period. This finding highlights the importance of maintaining large contiguous areas of spatially and temporally variable resources to allow animals to compensate behaviourally for changing climate-driven resource patterns. PMID:26009244

  8. Final Technical Report on STTR Project DE-FG02-06ER86281 Particle Tracking in Matter-Dominated Beam Lines (G4beamline)

    Energy Technology Data Exchange (ETDEWEB)

    Muons, Inc.

    2011-05-19

    This project has been for software development of the G4beamline [1] program, which is a particle-tracking simulation program based on the Geant4 toolkit [2], optimized for beam lines. This program can perform more realistic simulations than most alternatives, while being significantly easier to use by physicists. This project has fostered the general acceptance of G4beamline within the muon community, and has assisted in expanding its role outside that community. During this project, the G4beamline user community has grown from about a half-dozen users to more than 200 users around the world. This project also validated our business decision to keep G4beamline an open-source program, judging that an STTR project would provide more development resources than would marketing and selling the program. G4beamline is freely available to the physics community, and has been well validated against experiments and other codes within its domain. Muons, Inc. continues to support and develop the program, and a major part of the company's continued success and growth is directly related to our expertise in applying this program to interesting applications.

  9. Characterization of groundwater flow and transport in the General Separations Areas, Savannah River Plant: Flow model refinement and particle-tracking analysis report

    Energy Technology Data Exchange (ETDEWEB)

    Duffield, G.M.; Buss, D.R.; Root, R.W. Jr.; Hughes, S.S.; Mercer, J.W. [GeoTrans, Inc., Sterling, VA (United States)

    1986-03-01

    The Department of Energy (DOE) is preparing the necessary NEPA documentation for an Environmental Impact Statement (EIS) to address the waste disposal activities for groundwater protection at the Savannah River Plant (SRP). For purposes of this EIA, the areas within the plant have been separated into 26 functional groups based primarily on hydrogeologic setting and types of disposed waste materials. The overall objective is to provide an appropriate quantitative assessment of the environmental impacts from past and future operations within each functional group. The analysis from each functional group will be integrated to assess the impacts of plant-wide operations. A flexible approach to quantifying the impacts using several methods of quantitative analysis is being employed. Numerical flow and transport modeling is one method being applied to several functional groups. The scope of work can be divided into four broad categories: (1) Data Review and Conceptual Model Development, (2) Groundwater Flow Model Construction and Refinement, (3) Solute Transport Model Construction, and (4) Remedial Alternative Simulations. The major topics covered in this report are: (1) summary of the hydrogeologic conditions of the area, (2) observed flow velocities at the study site, (3) a summary of results from the preliminary flow modeling effort, (4) flow model refinement and results, and (5) particle tracking analyses based on the refined flow model.

  10. Single-particle tracking uncovers dynamics of glutamate-induced retrograde transport of NF-κB p65 in living neurons.

    Science.gov (United States)

    Widera, Darius; Klenke, Christin; Nair, Deepak; Heidbreder, Meike; Malkusch, Sebastian; Sibarita, Jean-Baptiste; Choquet, Daniel; Kaltschmidt, Barbara; Heilemann, Mike; Kaltschmidt, Christian

    2016-10-01

    Retrograde transport of NF-κB from the synapse to the nucleus in neurons is mediated by the dynein/dynactin motor complex and can be triggered by synaptic activation. The caliber of axons is highly variable ranging down to 100 nm, aggravating the investigation of transport processes in neurites of living neurons using conventional light microscopy. We quantified for the first time the transport of the NF-κB subunit p65 using high-density single-particle tracking in combination with photoactivatable fluorescent proteins in living mouse hippocampal neurons. We detected an increase of the mean diffusion coefficient ([Formula: see text]) in neurites from [Formula: see text] to [Formula: see text] after stimulation with glutamate. We further observed that the relative amount of retrogradely transported p65 molecules is increased after stimulation. Glutamate treatment resulted in an increase of the mean retrograde velocity from [Formula: see text] to [Formula: see text], whereas a velocity increase from [Formula: see text] to [Formula: see text] was observed for anterogradely transported p65. This study demonstrates for the first time that glutamate stimulation leads to an increased mobility of single NF-κB p65 molecules in neurites of living hippocampal neurons. PMID:27226975

  11. MODPATH-LGR; documentation of a computer program for particle tracking in shared-node locally refined grids by using MODFLOW-LGR

    Science.gov (United States)

    Dickinson, Jesse E.; Hanson, R.T.; Mehl, Steffen W.; Hill, Mary C.

    2011-01-01

    The computer program described in this report, MODPATH-LGR, is designed to allow simulation of particle tracking in locally refined grids. The locally refined grids are simulated by using MODFLOW-LGR, which is based on MODFLOW-2005, the three-dimensional groundwater-flow model published by the U.S. Geological Survey. The documentation includes brief descriptions of the methods used and detailed descriptions of the required input files and how the output files are typically used. The code for this model is available for downloading from the World Wide Web from a U.S. Geological Survey software repository. The repository is accessible from the U.S. Geological Survey Water Resources Information Web page at http://water.usgs.gov/software/ground_water.html. The performance of the MODPATH-LGR program has been tested in a variety of applications. Future applications, however, might reveal errors that were not detected in the test simulations. Users are requested to notify the U.S. Geological Survey of any errors found in this document or the computer program by using the email address available on the Web site. Updates might occasionally be made to this document and to the MODPATH-LGR program, and users should check the Web site periodically.

  12. Ant Optimized Particle Filter For Visual Tracking%蚁群优化粒子滤波视觉跟踪算法

    Institute of Scientific and Technical Information of China (English)

    苗彬; 侯燕

    2014-01-01

    针对传统的基于再采样方法的粒子滤波算法存在的样本贫乏现象,提出采用蚁群优化的思想取代再采样步骤,通过有效模拟的蚂蚁觅食的生物特性,抑制样本贫乏现象,从而提高目标跟踪的准确性。实验结果表明,该算法能够有效处理目标快速运动、目标遮挡、交互等难题,表现出较好的鲁棒性。%The thought of ant optimization replacing resampling step is proposed to solve the sample deficiency problem caused by the traditional particle filter based on resampling method. By effectively simulating the foraging behavior of ants,the proposed algorithm can suppress the impoverishment problem of sample and consequently im-prove the target tracking accuracy. The experimental results show that the proposed algorithm is robust and efficient in dealing with the issues of rapid motion,object occlusion and interaction.

  13. IHadoop: Asynchronous iterations for MapReduce

    KAUST Repository

    Elnikety, Eslam Mohamed Ibrahim

    2011-11-01

    MapReduce is a distributed programming frame-work designed to ease the development of scalable data-intensive applications for large clusters of commodity machines. Most machine learning and data mining applications involve iterative computations over large datasets, such as the Web hyperlink structures and social network graphs. Yet, the MapReduce model does not efficiently support this important class of applications. The architecture of MapReduce, most critically its dataflow techniques and task scheduling, is completely unaware of the nature of iterative applications; tasks are scheduled according to a policy that optimizes the execution for a single iteration which wastes bandwidth, I/O, and CPU cycles when compared with an optimal execution for a consecutive set of iterations. This work presents iHadoop, a modified MapReduce model, and an associated implementation, optimized for iterative computations. The iHadoop model schedules iterations asynchronously. It connects the output of one iteration to the next, allowing both to process their data concurrently. iHadoop\\'s task scheduler exploits inter-iteration data locality by scheduling tasks that exhibit a producer/consumer relation on the same physical machine allowing a fast local data transfer. For those iterative applications that require satisfying certain criteria before termination, iHadoop runs the check concurrently during the execution of the subsequent iteration to further reduce the application\\'s latency. This paper also describes our implementation of the iHadoop model, and evaluates its performance against Hadoop, the widely used open source implementation of MapReduce. Experiments using different data analysis applications over real-world and synthetic datasets show that iHadoop performs better than Hadoop for iterative algorithms, reducing execution time of iterative applications by 25% on average. Furthermore, integrating iHadoop with HaLoop, a variant Hadoop implementation that caches

  14. Efficiency asynchronous application programming language Python

    OpenAIRE

    Толстікова, О. В.; Національний авіаційний університет; Мирошниченко, І. С.; Національний авіаційний університет; Коцюр, А. Б.; Національний авіаційний університет

    2016-01-01

    Consider tools that implement asynchronous programming in Python and allow more efficient use ofasynchronous programming applications. The efficiency of the module asyncio (PEP 3156) incomparison with classical spivprohramamy Рассмотрены инструменты, которые реализуют асинхронное программирование в языкеPython и позволяют повысить эффективность использования программирования асинхронныхприложений. Показана эффективность работы модуля asyncio (PEP 3156) по сравнению с классическими сопрогра...

  15. Asynchronous reference frame agreement in a quantum network

    Science.gov (United States)

    Islam, Tanvirul; Wehner, Stephanie

    2016-03-01

    An efficient implementation of many multiparty protocols for quantum networks requires that all the nodes in the network share a common reference frame. Establishing such a reference frame from scratch is especially challenging in an asynchronous network where network links might have arbitrary delays and the nodes do not share synchronised clocks. In this work, we study the problem of establishing a common reference frame in an asynchronous network of n nodes of which at most t are affected by arbitrary unknown error, and the identities of the faulty nodes are not known. We present a protocol that allows all the correctly functioning nodes to agree on a common reference frame as long as the network graph is complete and not more than t\\lt n/4 nodes are faulty. As the protocol is asynchronous, it can be used with some assumptions to synchronise clocks over a network. Also, the protocol has the appealing property that it allows any existing two-node asynchronous protocol for reference frame agreement to be lifted to a robust protocol for an asynchronous quantum network.

  16. Analysis and Modeling of Wangqing Oil Shale Drying Characteristics in a Novel Fluidized Bed Dryer with Asynchronous Rotating Air Distributor

    Institute of Scientific and Technical Information of China (English)

    Yang Ning; Zhou Yunlong; Miao Yanan

    2016-01-01

    In order to replace the conventional distributor, a novel asynchronous rotating air distributor, which can optimize the drying ability of lfuidized bed and strengthen the drying performance of oil shale particles, is creatively designed in this study. The rotating speed of the asynchronous rotating air distributor with an embedded center disk and an encircling disk is regulated to achieve the different air supply conditions. The impacts of different drying conditions on the drying characteristic of Wangqing oil shale particles are studied with the help of electronic scales. The dynamics of experimental data is analyzed with 9 common drying models. The results indicate that the particles distribution in lfuidized bed can be improved and the drying time can be reduced by decreasing the rotating speed of the embedded center disk and increasing the rotating speed of the encircling disk. The drying process of oil shale particles involves a rising drying rate period, a constant drying rate period and a falling drying rate period. Regulating the air distributor rotating speed reasonably will accelerate the shift of particles from the rising drying rate period to the falling drying rate period directly. The two-term model ifts properly the oil shale particles drying simulation among 9 drying models at different air supply conditions. Yet the air absorbed in the particles’ pores is diffused along with the moisture evaporation, and a small amount of moisture remains on the wall of lfuidized bed in each experiment, thus, the values of drying simulation are less than the experimental values.

  17. READ-EVAL-PRINT in Parallel and Asynchronous Proof-checking

    Directory of Open Access Journals (Sweden)

    Makarius Wenzel

    2013-07-01

    Full Text Available The LCF tradition of interactive theorem proving, which was started by Milner in the 1970-ies, appears to be tied to the classic READ-EVAL-PRINT-LOOP of sequential and synchronous evaluation of prover commands. We break up this loop and retrofit the read-eval-print phases into a model of parallel and asynchronous proof processing. Thus we explain some key concepts of the Isabelle/Scala approach to prover interaction and integration, and the Isabelle/jEdit Prover IDE as front-end technology. We hope to open up the scientific discussion about non-trivial interaction models for ITP systems again, and help getting other old-school proof assistants on a similar track.

  18. Asynchronous event-based corner detection and matching.

    Science.gov (United States)

    Clady, Xavier; Ieng, Sio-Hoi; Benosman, Ryad

    2015-06-01

    This paper introduces an event-based luminance-free method to detect and match corner events from the output of asynchronous event-based neuromorphic retinas. The method relies on the use of space-time properties of moving edges. Asynchronous event-based neuromorphic retinas are composed of autonomous pixels, each of them asynchronously generating "spiking" events that encode relative changes in pixels' illumination at high temporal resolutions. Corner events are defined as the spatiotemporal locations where the aperture problem can be solved using the intersection of several geometric constraints in events' spatiotemporal spaces. A regularization process provides the required constraints, i.e. the motion attributes of the edges with respect to their spatiotemporal locations using local geometric properties of visual events. Experimental results are presented on several real scenes showing the stability and robustness of the detection and matching. PMID:25828960

  19. A Loosely Synchronizing Asynchronous Router for TDM-Scheduled NOCs

    DEFF Research Database (Denmark)

    Kotleas, Ioannis; Humphreys, Dean; Sørensen, Rasmus Bo;

    2014-01-01

    This paper presents an asynchronous router design for use in time-division-multiplexed (TDM) networks-on-chip. Unlike existing synchronous, mesochronous and asynchronous router designs with similar functionality, the router is able to silently skip over cycles/TDM-slots where no traffic is...... scheduled and hence avoid all switching activity in the idle links and router ports. In this way switching activity is reduced to the minimum possible amount. The fact that this relaxed synchronization is sufficient to implement TDM scheduling represents a contribution at the conceptual level. The idea can...... only be implemented using asynchronous circuit techniques. To this end, the paper explores the use of “click-element” templates. Click-element templates use only flipflops and conventional gates, and this greatly simplifies the design process when using conventional EDA tools and standard cell...

  20. A Novel Multiuser Detector for Asynchronous CDMA System

    Institute of Scientific and Technical Information of China (English)

    LIANGXint; SHANGYong; LIANGQinglin; XIANGHaige

    2004-01-01

    The decorrelating and the MMSE (Minimum mean square error) multiuser detector for asynchronous CDMA (Code devision multiple access) system are ideally anticausal infinite memory-length detectors. Asa result~ in practice they have to be approximately implemented with finite-memory structure, and the process delay in detection is unavoidable. Based on the analysis of a new signal model for asynchronous system, a novel multiuser detector for asynchronous CDMA system is proposed in this paper~ which is termed as DF-IC-MMSE (Decision ,feedback interference cancellation-MMSE) detector. It's the detection statistics that makes the DF-IC-MMSE-detector basically different from other traditional ones. The DF-IC-MMSE detector can be ideally implemented with Causal finite memory-length structure, and cause no delay in symbol detection. Simulations show that the performance of DF-IC-MMSE detector is almost identical to that of the ideal MMSE detector.