Science.gov

Sample records for efficient parallel processing

  1. Efficient multitasking: parallel versus serial processing of multiple tasks

    PubMed Central

    Fischer, Rico; Plessow, Franziska

    2015-01-01

    In the context of performance optimizations in multitasking, a central debate has unfolded in multitasking research around whether cognitive processes related to different tasks proceed only sequentially (one at a time), or can operate in parallel (simultaneously). This review features a discussion of theoretical considerations and empirical evidence regarding parallel versus serial task processing in multitasking. In addition, we highlight how methodological differences and theoretical conceptions determine the extent to which parallel processing in multitasking can be detected, to guide their employment in future research. Parallel and serial processing of multiple tasks are not mutually exclusive. Therefore, questions focusing exclusively on either task-processing mode are too simplified. We review empirical evidence and demonstrate that shifting between more parallel and more serial task processing critically depends on the conditions under which multiple tasks are performed. We conclude that efficient multitasking is reflected by the ability of individuals to adjust multitasking performance to environmental demands by flexibly shifting between different processing strategies of multiple task-component scheduling. PMID:26441742

  2. Efficient multitasking: parallel versus serial processing of multiple tasks.

    PubMed

    Fischer, Rico; Plessow, Franziska

    2015-01-01

    In the context of performance optimizations in multitasking, a central debate has unfolded in multitasking research around whether cognitive processes related to different tasks proceed only sequentially (one at a time), or can operate in parallel (simultaneously). This review features a discussion of theoretical considerations and empirical evidence regarding parallel versus serial task processing in multitasking. In addition, we highlight how methodological differences and theoretical conceptions determine the extent to which parallel processing in multitasking can be detected, to guide their employment in future research. Parallel and serial processing of multiple tasks are not mutually exclusive. Therefore, questions focusing exclusively on either task-processing mode are too simplified. We review empirical evidence and demonstrate that shifting between more parallel and more serial task processing critically depends on the conditions under which multiple tasks are performed. We conclude that efficient multitasking is reflected by the ability of individuals to adjust multitasking performance to environmental demands by flexibly shifting between different processing strategies of multiple task-component scheduling. PMID:26441742

  3. Efficient multitasking: parallel versus serial processing of multiple tasks.

    PubMed

    Fischer, Rico; Plessow, Franziska

    2015-01-01

    In the context of performance optimizations in multitasking, a central debate has unfolded in multitasking research around whether cognitive processes related to different tasks proceed only sequentially (one at a time), or can operate in parallel (simultaneously). This review features a discussion of theoretical considerations and empirical evidence regarding parallel versus serial task processing in multitasking. In addition, we highlight how methodological differences and theoretical conceptions determine the extent to which parallel processing in multitasking can be detected, to guide their employment in future research. Parallel and serial processing of multiple tasks are not mutually exclusive. Therefore, questions focusing exclusively on either task-processing mode are too simplified. We review empirical evidence and demonstrate that shifting between more parallel and more serial task processing critically depends on the conditions under which multiple tasks are performed. We conclude that efficient multitasking is reflected by the ability of individuals to adjust multitasking performance to environmental demands by flexibly shifting between different processing strategies of multiple task-component scheduling.

  4. Efficient biased random bit generation for parallel processing

    SciTech Connect

    Slone, D.M.

    1994-09-28

    A lattice gas automaton was implemented on a massively parallel machine (the BBN TC2000) and a vector supercomputer (the CRAY C90). The automaton models Burgers equation {rho}t + {rho}{rho}{sub x} = {nu}{rho}{sub xx} in 1 dimension. The lattice gas evolves by advecting and colliding pseudo-particles on a 1-dimensional, periodic grid. The specific rules for colliding particles are stochastic in nature and require the generation of many billions of random numbers to create the random bits necessary for the lattice gas. The goal of the thesis was to speed up the process of generating the random bits and thereby lessen the computational bottleneck of the automaton.

  5. Reliable and Efficient Parallel Processing Algorithms and Architectures for Modern Signal Processing. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Liu, Kuojuey Ray

    1990-01-01

    Least-squares (LS) estimations and spectral decomposition algorithms constitute the heart of modern signal processing and communication problems. Implementations of recursive LS and spectral decomposition algorithms onto parallel processing architectures such as systolic arrays with efficient fault-tolerant schemes are the major concerns of this dissertation. There are four major results in this dissertation. First, we propose the systolic block Householder transformation with application to the recursive least-squares minimization. It is successfully implemented on a systolic array with a two-level pipelined implementation at the vector level as well as at the word level. Second, a real-time algorithm-based concurrent error detection scheme based on the residual method is proposed for the QRD RLS systolic array. The fault diagnosis, order degraded reconfiguration, and performance analysis are also considered. Third, the dynamic range, stability, error detection capability under finite-precision implementation, order degraded performance, and residual estimation under faulty situations for the QRD RLS systolic array are studied in details. Finally, we propose the use of multi-phase systolic algorithms for spectral decomposition based on the QR algorithm. Two systolic architectures, one based on triangular array and another based on rectangular array, are presented for the multiphase operations with fault-tolerant considerations. Eigenvectors and singular vectors can be easily obtained by using the multi-pase operations. Performance issues are also considered.

  6. Parallel Information Processing.

    ERIC Educational Resources Information Center

    Rasmussen, Edie M.

    1992-01-01

    Examines parallel computer architecture and the use of parallel processors for text. Topics discussed include parallel algorithms; performance evaluation; parallel information processing; parallel access methods for text; parallel and distributed information retrieval systems; parallel hardware for text; and network models for information…

  7. Special parallel processing workshop

    SciTech Connect

    1994-12-01

    This report contains viewgraphs from the Special Parallel Processing Workshop. These viewgraphs deal with topics such as parallel processing performance, message passing, queue structure, and other basic concept detailing with parallel processing.

  8. A new strategy for efficient solar energy conversion: Parallel-processing with surface plasmons

    NASA Technical Reports Server (NTRS)

    Anderson, L. M.

    1982-01-01

    This paper introduces an advanced concept for direct conversion of sunlight to electricity, which aims at high efficiency by tailoring the conversion process to separate energy bands within the broad solar spectrum. The objective is to obtain a high level of spectrum-splitting without sequential losses or unique materials for each frequency band. In this concept, sunlight excites a spectrum of surface plasma waves which are processed in parallel on the same metal film. The surface plasmons transport energy to an array of metal-barrier-semiconductor diodes, where energy is extracted by inelastic tunneling. Diodes are tuned to different frequency bands by selecting the operating voltage and geometry, but all diodes share the same materials.

  9. Automatic analysis (aa): efficient neuroimaging workflows and parallel processing using Matlab and XML.

    PubMed

    Cusack, Rhodri; Vicente-Grabovetsky, Alejandro; Mitchell, Daniel J; Wild, Conor J; Auer, Tibor; Linke, Annika C; Peelle, Jonathan E

    2014-01-01

    Recent years have seen neuroimaging data sets becoming richer, with larger cohorts of participants, a greater variety of acquisition techniques, and increasingly complex analyses. These advances have made data analysis pipelines complicated to set up and run (increasing the risk of human error) and time consuming to execute (restricting what analyses are attempted). Here we present an open-source framework, automatic analysis (aa), to address these concerns. Human efficiency is increased by making code modular and reusable, and managing its execution with a processing engine that tracks what has been completed and what needs to be (re)done. Analysis is accelerated by optional parallel processing of independent tasks on cluster or cloud computing resources. A pipeline comprises a series of modules that each perform a specific task. The processing engine keeps track of the data, calculating a map of upstream and downstream dependencies for each module. Existing modules are available for many analysis tasks, such as SPM-based fMRI preprocessing, individual and group level statistics, voxel-based morphometry, tractography, and multi-voxel pattern analyses (MVPA). However, aa also allows for full customization, and encourages efficient management of code: new modules may be written with only a small code overhead. aa has been used by more than 50 researchers in hundreds of neuroimaging studies comprising thousands of subjects. It has been found to be robust, fast, and efficient, for simple-single subject studies up to multimodal pipelines on hundreds of subjects. It is attractive to both novice and experienced users. aa can reduce the amount of time neuroimaging laboratories spend performing analyses and reduce errors, expanding the range of scientific questions it is practical to address.

  10. Automatic analysis (aa): efficient neuroimaging workflows and parallel processing using Matlab and XML

    PubMed Central

    Cusack, Rhodri; Vicente-Grabovetsky, Alejandro; Mitchell, Daniel J.; Wild, Conor J.; Auer, Tibor; Linke, Annika C.; Peelle, Jonathan E.

    2015-01-01

    Recent years have seen neuroimaging data sets becoming richer, with larger cohorts of participants, a greater variety of acquisition techniques, and increasingly complex analyses. These advances have made data analysis pipelines complicated to set up and run (increasing the risk of human error) and time consuming to execute (restricting what analyses are attempted). Here we present an open-source framework, automatic analysis (aa), to address these concerns. Human efficiency is increased by making code modular and reusable, and managing its execution with a processing engine that tracks what has been completed and what needs to be (re)done. Analysis is accelerated by optional parallel processing of independent tasks on cluster or cloud computing resources. A pipeline comprises a series of modules that each perform a specific task. The processing engine keeps track of the data, calculating a map of upstream and downstream dependencies for each module. Existing modules are available for many analysis tasks, such as SPM-based fMRI preprocessing, individual and group level statistics, voxel-based morphometry, tractography, and multi-voxel pattern analyses (MVPA). However, aa also allows for full customization, and encourages efficient management of code: new modules may be written with only a small code overhead. aa has been used by more than 50 researchers in hundreds of neuroimaging studies comprising thousands of subjects. It has been found to be robust, fast, and efficient, for simple-single subject studies up to multimodal pipelines on hundreds of subjects. It is attractive to both novice and experienced users. aa can reduce the amount of time neuroimaging laboratories spend performing analyses and reduce errors, expanding the range of scientific questions it is practical to address. PMID:25642185

  11. Automatic analysis (aa): efficient neuroimaging workflows and parallel processing using Matlab and XML.

    PubMed

    Cusack, Rhodri; Vicente-Grabovetsky, Alejandro; Mitchell, Daniel J; Wild, Conor J; Auer, Tibor; Linke, Annika C; Peelle, Jonathan E

    2014-01-01

    Recent years have seen neuroimaging data sets becoming richer, with larger cohorts of participants, a greater variety of acquisition techniques, and increasingly complex analyses. These advances have made data analysis pipelines complicated to set up and run (increasing the risk of human error) and time consuming to execute (restricting what analyses are attempted). Here we present an open-source framework, automatic analysis (aa), to address these concerns. Human efficiency is increased by making code modular and reusable, and managing its execution with a processing engine that tracks what has been completed and what needs to be (re)done. Analysis is accelerated by optional parallel processing of independent tasks on cluster or cloud computing resources. A pipeline comprises a series of modules that each perform a specific task. The processing engine keeps track of the data, calculating a map of upstream and downstream dependencies for each module. Existing modules are available for many analysis tasks, such as SPM-based fMRI preprocessing, individual and group level statistics, voxel-based morphometry, tractography, and multi-voxel pattern analyses (MVPA). However, aa also allows for full customization, and encourages efficient management of code: new modules may be written with only a small code overhead. aa has been used by more than 50 researchers in hundreds of neuroimaging studies comprising thousands of subjects. It has been found to be robust, fast, and efficient, for simple-single subject studies up to multimodal pipelines on hundreds of subjects. It is attractive to both novice and experienced users. aa can reduce the amount of time neuroimaging laboratories spend performing analyses and reduce errors, expanding the range of scientific questions it is practical to address. PMID:25642185

  12. Efficient Parallel Video Processing Techniques on GPU: From Framework to Implementation

    PubMed Central

    Su, Huayou; Wen, Mei; Wu, Nan; Ren, Ju; Zhang, Chunyuan

    2014-01-01

    Through reorganizing the execution order and optimizing the data structure, we proposed an efficient parallel framework for H.264/AVC encoder based on massively parallel architecture. We implemented the proposed framework by CUDA on NVIDIA's GPU. Not only the compute intensive components of the H.264 encoder are parallelized but also the control intensive components are realized effectively, such as CAVLC and deblocking filter. In addition, we proposed serial optimization methods, including the multiresolution multiwindow for motion estimation, multilevel parallel strategy to enhance the parallelism of intracoding as much as possible, component-based parallel CAVLC, and direction-priority deblocking filter. More than 96% of workload of H.264 encoder is offloaded to GPU. Experimental results show that the parallel implementation outperforms the serial program by 20 times of speedup ratio and satisfies the requirement of the real-time HD encoding of 30 fps. The loss of PSNR is from 0.14 dB to 0.77 dB, when keeping the same bitrate. Through the analysis to the kernels, we found that speedup ratios of the compute intensive algorithms are proportional with the computation power of the GPU. However, the performance of the control intensive parts (CAVLC) is much related to the memory bandwidth, which gives an insight for new architecture design. PMID:24757432

  13. Efficient Process Migration for Parallel Processing on Non-Dedicated Networks of Workstations

    NASA Technical Reports Server (NTRS)

    Chanchio, Kasidit; Sun, Xian-He

    1996-01-01

    This paper presents the design and preliminary implementation of MpPVM, a software system that supports process migration for PVM application programs in a non-dedicated heterogeneous computing environment. New concepts of migration point as well as migration point analysis and necessary data analysis are introduced. In MpPVM, process migrations occur only at previously inserted migration points. Migration point analysis determines appropriate locations to insert migration points; whereas, necessary data analysis provides a minimum set of variables to be transferred at each migration pint. A new methodology to perform reliable point-to-point data communications in a migration environment is also discussed. Finally, a preliminary implementation of MpPVM and its experimental results are presented, showing the correctness and promising performance of our process migration mechanism in a scalable non-dedicated heterogeneous computing environment. While MpPVM is developed on top of PVM, the process migration methodology introduced in this study is general and can be applied to any distributed software environment.

  14. Combining message-passing and inter-process communication in SMP-hybrid cluster for efficient parallel medical image analysis

    NASA Astrophysics Data System (ADS)

    Tan, Sean C. S.; Schmidt, Bertil

    2004-11-01

    Efficient analysis of medical images to assist physician"s decision making is an important task. However, the analysis of such images often requires sophisticated segmentation and classification algorithms. An approach to speed up these time consuming operations is to use parallel processing. In this paper a new parallel system for medical image analysis is presented. The system combines distributed and shared memory architectures using MPI and the inter-process communication switching mechanism (IPC). MPI is used to communicate between nodes and shared-memory IPC is used to perform shared memory operations among processors within a node. We show how to map a clinical endoscopic image analysis algorithm efficiently onto this architecture. This results in an implementation with significant runtime savings.

  15. Efficiency of parallel direct optimization

    NASA Technical Reports Server (NTRS)

    Janies, D. A.; Wheeler, W. C.

    2001-01-01

    Tremendous progress has been made at the level of sequential computation in phylogenetics. However, little attention has been paid to parallel computation. Parallel computing is particularly suited to phylogenetics because of the many ways large computational problems can be broken into parts that can be analyzed concurrently. In this paper, we investigate the scaling factors and efficiency of random addition and tree refinement strategies using the direct optimization software, POY, on a small (10 slave processors) and a large (256 slave processors) cluster of networked PCs running LINUX. These algorithms were tested on several data sets composed of DNA and morphology ranging from 40 to 500 taxa. Various algorithms in POY show fundamentally different properties within and between clusters. All algorithms are efficient on the small cluster for the 40-taxon data set. On the large cluster, multibuilding exhibits excellent parallel efficiency, whereas parallel building is inefficient. These results are independent of data set size. Branch swapping in parallel shows excellent speed-up for 16 slave processors on the large cluster. However, there is no appreciable speed-up for branch swapping with the further addition of slave processors (>16). This result is independent of data set size. Ratcheting in parallel is efficient with the addition of up to 32 processors in the large cluster. This result is independent of data set size. c2001 The Willi Hennig Society.

  16. Parallel processing and expert systems

    NASA Technical Reports Server (NTRS)

    Yan, Jerry C.; Lau, Sonie

    1991-01-01

    Whether it be monitoring the thermal subsystem of Space Station Freedom, or controlling the navigation of the autonomous rover on Mars, NASA missions in the 90's cannot enjoy an increased level of autonomy without the efficient use of expert systems. Merely increasing the computational speed of uniprocessors may not be able to guarantee that real time demands are met for large expert systems. Speed-up via parallel processing must be pursued alongside the optimization of sequential implementations. Prototypes of parallel expert systems have been built at universities and industrial labs in the U.S. and Japan. The state-of-the-art research in progress related to parallel execution of expert systems was surveyed. The survey is divided into three major sections: (1) multiprocessors for parallel expert systems; (2) parallel languages for symbolic computations; and (3) measurements of parallelism of expert system. Results to date indicate that the parallelism achieved for these systems is small. In order to obtain greater speed-ups, data parallelism and application parallelism must be exploited.

  17. Parallel processing and expert systems

    NASA Technical Reports Server (NTRS)

    Lau, Sonie; Yan, Jerry C.

    1991-01-01

    Whether it be monitoring the thermal subsystem of Space Station Freedom, or controlling the navigation of the autonomous rover on Mars, NASA missions in the 1990s cannot enjoy an increased level of autonomy without the efficient implementation of expert systems. Merely increasing the computational speed of uniprocessors may not be able to guarantee that real-time demands are met for larger systems. Speedup via parallel processing must be pursued alongside the optimization of sequential implementations. Prototypes of parallel expert systems have been built at universities and industrial laboratories in the U.S. and Japan. The state-of-the-art research in progress related to parallel execution of expert systems is surveyed. The survey discusses multiprocessors for expert systems, parallel languages for symbolic computations, and mapping expert systems to multiprocessors. Results to date indicate that the parallelism achieved for these systems is small. The main reasons are (1) the body of knowledge applicable in any given situation and the amount of computation executed by each rule firing are small, (2) dividing the problem solving process into relatively independent partitions is difficult, and (3) implementation decisions that enable expert systems to be incrementally refined hamper compile-time optimization. In order to obtain greater speedups, data parallelism and application parallelism must be exploited.

  18. Parallel processing for scientific computations

    NASA Technical Reports Server (NTRS)

    Alkhatib, Hasan S.

    1991-01-01

    The main contribution of the effort in the last two years is the introduction of the MOPPS system. After doing extensive literature search, we introduced the system which is described next. MOPPS employs a new solution to the problem of managing programs which solve scientific and engineering applications on a distributed processing environment. Autonomous computers cooperate efficiently in solving large scientific problems with this solution. MOPPS has the advantage of not assuming the presence of any particular network topology or configuration, computer architecture, or operating system. It imposes little overhead on network and processor resources while efficiently managing programs concurrently. The core of MOPPS is an intelligent program manager that builds a knowledge base of the execution performance of the parallel programs it is managing under various conditions. The manager applies this knowledge to improve the performance of future runs. The program manager learns from experience.

  19. EFFICIENT SCHEDULING OF PARALLEL JOBS ON MASSIVELY PARALLEL SYSTEMS

    SciTech Connect

    F. PETRINI; W. FENG

    1999-09-01

    We present buffered coscheduling, a new methodology to multitask parallel jobs in a message-passing environment and to develop parallel programs that can pave the way to the efficient implementation of a distributed operating system. Buffered coscheduling is based on three innovative techniques: communication buffering, strobing, and non-blocking communication. By leveraging these techniques, we can perform effective optimizations based on the global status of the parallel machine rather than on the limited knowledge available locally to each processor. The advantages of buffered coscheduling include higher resource utilization, reduced communication overhead, efficient implementation of low-control strategies and fault-tolerant protocols, accurate performance modeling, and a simplified yet still expressive parallel programming model. Preliminary experimental results show that buffered coscheduling is very effective in increasing the overall performance in the presence of load imbalance and communication-intensive workloads.

  20. Applications of Parallel Processing in Configuration Analyses

    NASA Technical Reports Server (NTRS)

    Sundaram, Ppchuraman; Hager, James O.; Biedron, Robert T.

    1999-01-01

    The paper presents the recent progress made towards developing an efficient and user-friendly parallel environment for routine analysis of large CFD problems. The coarse-grain parallel version of the CFL3D Euler/Navier-Stokes analysis code, CFL3Dhp, has been ported onto most available parallel platforms. The CFL3Dhp solution accuracy on these parallel platforms has been verified with the CFL3D sequential analyses. User-friendly pre- and post-processing tools that enable a seamless transfer from sequential to parallel processing have been written. Static load balancing tool for CFL3Dhp analysis has also been implemented for achieving good parallel efficiency. For large problems, load balancing efficiency as high as 95% can be achieved even when large number of processors are used. Linear scalability of the CFL3Dhp code with increasing number of processors has also been shown using a large installed transonic nozzle boattail analysis. To highlight the fast turn-around time of parallel processing, the TCA full configuration in sideslip Navier-Stokes drag polar at supersonic cruise has been obtained in a day. CFL3Dhp is currently being used as a production analysis tool.

  1. Experimental Parallel-Processing Computer

    NASA Technical Reports Server (NTRS)

    Mcgregor, J. W.; Salama, M. A.

    1986-01-01

    Master processor supervises slave processors, each with its own memory. Computer with parallel processing serves as inexpensive tool for experimentation with parallel mathematical algorithms. Speed enhancement obtained depends on both nature of problem and structure of algorithm used. In parallel-processing architecture, "bank select" and control signals determine which one, if any, of N slave processor memories accessible to master processor at any given moment. When so selected, slave memory operates as part of master computer memory. When not selected, slave memory operates independently of main memory. Slave processors communicate with each other via input/output bus.

  2. Knowledge representation into Ada parallel processing

    NASA Technical Reports Server (NTRS)

    Masotto, Tom; Babikyan, Carol; Harper, Richard

    1990-01-01

    The Knowledge Representation into Ada Parallel Processing project is a joint NASA and Air Force funded project to demonstrate the execution of intelligent systems in Ada on the Charles Stark Draper Laboratory fault-tolerant parallel processor (FTPP). Two applications were demonstrated - a portion of the adaptive tactical navigator and a real time controller. Both systems are implemented as Activation Framework Objects on the Activation Framework intelligent scheduling mechanism developed by Worcester Polytechnic Institute. The implementations, results of performance analyses showing speedup due to parallelism and initial efficiency improvements are detailed and further areas for performance improvements are suggested.

  3. Parallel processing spacecraft communication system

    NASA Technical Reports Server (NTRS)

    Bolotin, Gary S. (Inventor); Donaldson, James A. (Inventor); Luong, Huy H. (Inventor); Wood, Steven H. (Inventor)

    1998-01-01

    An uplink controlling assembly speeds data processing using a special parallel codeblock technique. A correct start sequence initiates processing of a frame. Two possible start sequences can be used; and the one which is used determines whether data polarity is inverted or non-inverted. Processing continues until uncorrectable errors are found. The frame ends by intentionally sending a block with an uncorrectable error. Each of the codeblocks in the frame has a channel ID. Each channel ID can be separately processed in parallel. This obviates the problem of waiting for error correction processing. If that channel number is zero, however, it indicates that the frame of data represents a critical command only. That data is handled in a special way, independent of the software. Otherwise, the processed data further handled using special double buffering techniques to avoid problems from overrun. When overrun does occur, the system takes action to lose only the oldest data.

  4. Parallel strategies for SAR processing

    NASA Astrophysics Data System (ADS)

    Segoviano, Jesus A.

    2004-12-01

    This article proposes a series of strategies for improving the computer process of the Synthetic Aperture Radar (SAR) signal treatment, following the three usual lines of action to speed up the execution of any computer program. On the one hand, it is studied the optimization of both, the data structures and the application architecture used on it. On the other hand it is considered a hardware improvement. For the former, they are studied both, the usually employed SAR process data structures, proposing the use of parallel ones and the way the parallelization of the algorithms employed on the process is implemented. Besides, the parallel application architecture classifies processes between fine/coarse grain. These are assigned to individual processors or separated in a division among processors, all of them in their corresponding architectures. For the latter, it is studied the hardware employed on the computer parallel process used in the SAR handling. The improvement here refers to several kinds of platforms in which the SAR process is implemented, shared memory multicomputers, and distributed memory multiprocessors. A comparison between them gives us some guidelines to follow in order to get a maximum throughput with a minimum latency and a maximum effectiveness with a minimum cost, all together with a limited complexness. It is concluded and described, that the approach consisting of the processing of the algorithms in a GNU/Linux environment, together with a Beowulf cluster platform offers, under certain conditions, the best compromise between performance and cost, and promises the major development in the future for the Synthetic Aperture Radar computer power thirsty applications in the next years.

  5. Efficient communication in massively parallel computers

    SciTech Connect

    Cypher, R.E.

    1989-01-01

    A fundamental operation in parallel computation is sorting. Sorting is important not only because it is required by many algorithms, but also because it can be used to implement irregular, pointer-based communication. The author studies two algorithms for sorting in massively parallel computers. First, he examines Shellsort. Shellsort is a sorting algorithm that is based on a sequence of parameters called increments. Shellsort can be used to create a parallel sorting device known as a sorting network. Researchers have suggested that if the correct increment sequence is used, an optimal size sorting network can be obtained. All published increment sequences have been monotonically decreasing. He shows that no monotonically decreasing increment sequence will yield an optimal size sorting network. Second, he presents a sorting algorithm called Cubesort. Cubesort is the fastest known sorting algorithm for a variety of parallel computers aver a wide range of parameters. He also presents a paradigm for developing parallel algorithms that have efficient communication. The paradigm, called the data reduction paradigm, consists of using a divide-and-conquer strategy. Both the division and combination phases of the divide-and-conquer algorithm may require irregular, pointer-based communication between processors. However, the problem is divided so as to limit the amount of data that must be communicated. As a result the communication can be performed efficiently. He presents data reduction algorithms for the image component labeling problem, the closest pair problem and four versions of the parallel prefix problem.

  6. Massively parallel femtosecond laser processing.

    PubMed

    Hasegawa, Satoshi; Ito, Haruyasu; Toyoda, Haruyoshi; Hayasaki, Yoshio

    2016-08-01

    Massively parallel femtosecond laser processing with more than 1000 beams was demonstrated. Parallel beams were generated by a computer-generated hologram (CGH) displayed on a spatial light modulator (SLM). The key to this technique is to optimize the CGH in the laser processing system using a scheme called in-system optimization. It was analytically demonstrated that the number of beams is determined by the horizontal number of pixels in the SLM NSLM that is imaged at the pupil plane of an objective lens and a distance parameter pd obtained by dividing the distance between adjacent beams by the diffraction-limited beam diameter. A performance limitation of parallel laser processing in our system was estimated at NSLM of 250 and pd of 7.0. Based on these parameters, the maximum number of beams in a hexagonal close-packed structure was calculated to be 1189 by using an analytical equation. PMID:27505815

  7. Efficient parallel global garbage collection on massively parallel computers

    SciTech Connect

    Kamada, Tomio; Matsuoka, Satoshi; Yonezawa, Akinori

    1994-12-31

    On distributed-memory high-performance MPPs where processors are interconnected by an asynchronous network, efficient Garbage Collection (GC) becomes difficult due to inter-node references and references within pending, unprocessed messages. The parallel global GC algorithm (1) takes advantage of reference locality, (2) efficiently traverses references over nodes, (3) admits minimum pause time of ongoing computations, and (4) has been shown to scale up to 1024 node MPPs. The algorithm employs a global weight counting scheme to substantially reduce message traffic. The two methods for confirming the arrival of pending messages are used: one counts numbers of messages and the other uses network `bulldozing.` Performance evaluation in actual implementations on a multicomputer with 32-1024 nodes, Fujitsu AP1000, reveals various favorable properties of the algorithm.

  8. On the design, analysis, and implementation of efficient parallel algorithms

    SciTech Connect

    Sohn, S.M.

    1989-01-01

    There is considerable interest in developing algorithms for a variety of parallel computer architectures. This is not a trivial problem, although for certain models great progress has been made. Recently, general-purpose parallel machines have become available commercially. These machines possess widely varying interconnection topologies and data/instruction access schemes. It is important, therefore, to develop methodologies and design paradigms for not only synthesizing parallel algorithms from initial problem specifications, but also for mapping algorithms between different architectures. This work has considered both of these problems. A systolic array consists of a large collection of simple processors that are interconnected in a uniform pattern. The author has studied in detain the problem of mapping systolic algorithms onto more general-purpose parallel architectures such as the hypercube. The hypercube architecture is notable due to its symmetry and high connectivity, characteristics which are conducive to the efficient embedding of parallel algorithms. Although the parallel-to-parallel mapping techniques have yielded efficient target algorithms, it is not surprising that an algorithm designed directly for a particular parallel model would achieve superior performance. In this context, the author has developed hypercube algorithms for some important problems in speech and signal processing, text processing, language processing and artificial intelligence. These algorithms were implemented on a 64-node NCUBE/7 hypercube machine in order to evaluate their performance.

  9. Multi-petascale highly efficient parallel supercomputer

    DOEpatents

    Asaad, Sameh; Bellofatto, Ralph E.; Blocksome, Michael A.; Blumrich, Matthias A.; Boyle, Peter; Brunheroto, Jose R.; Chen, Dong; Cher, Chen -Yong; Chiu, George L.; Christ, Norman; Coteus, Paul W.; Davis, Kristan D.; Dozsa, Gabor J.; Eichenberger, Alexandre E.; Eisley, Noel A.; Ellavsky, Matthew R.; Evans, Kahn C.; Fleischer, Bruce M.; Fox, Thomas W.; Gara, Alan; Giampapa, Mark E.; Gooding, Thomas M.; Gschwind, Michael K.; Gunnels, John A.; Hall, Shawn A.; Haring, Rudolf A.; Heidelberger, Philip; Inglett, Todd A.; Knudson, Brant L.; Kopcsay, Gerard V.; Kumar, Sameer; Mamidala, Amith R.; Marcella, James A.; Megerian, Mark G.; Miller, Douglas R.; Miller, Samuel J.; Muff, Adam J.; Mundy, Michael B.; O'Brien, John K.; O'Brien, Kathryn M.; Ohmacht, Martin; Parker, Jeffrey J.; Poole, Ruth J.; Ratterman, Joseph D.; Salapura, Valentina; Satterfield, David L.; Senger, Robert M.; Smith, Brian; Steinmacher-Burow, Burkhard; Stockdell, William M.; Stunkel, Craig B.; Sugavanam, Krishnan; Sugawara, Yutaka; Takken, Todd E.; Trager, Barry M.; Van Oosten, James L.; Wait, Charles D.; Walkup, Robert E.; Watson, Alfred T.; Wisniewski, Robert W.; Wu, Peng

    2015-07-14

    A Multi-Petascale Highly Efficient Parallel Supercomputer of 100 petaOPS-scale computing, at decreased cost, power and footprint, and that allows for a maximum packaging density of processing nodes from an interconnect point of view. The Supercomputer exploits technological advances in VLSI that enables a computing model where many processors can be integrated into a single Application Specific Integrated Circuit (ASIC). Each ASIC computing node comprises a system-on-chip ASIC utilizing four or more processors integrated into one die, with each having full access to all system resources and enabling adaptive partitioning of the processors to functions such as compute or messaging I/O on an application by application basis, and preferably, enable adaptive partitioning of functions in accordance with various algorithmic phases within an application, or if I/O or other processors are underutilized, then can participate in computation or communication nodes are interconnected by a five dimensional torus network with DMA that optimally maximize the throughput of packet communications between nodes and minimize latency.

  10. Parallel Processing at the High School Level.

    ERIC Educational Resources Information Center

    Sheary, Kathryn Anne

    This study investigated the ability of high school students to cognitively understand and implement parallel processing. Data indicates that most parallel processing is being taught at the university level. Instructional modules on C, Linux, and the parallel processing language, P4, were designed to show that high school students are highly…

  11. Parallel processing and medium-scale multiprocessors

    SciTech Connect

    Wouk, A.

    1989-01-01

    For some time, the community interested in large-scale scientific computing has been attempting to come to terms with parallel computation using a number of processors sufficient to make their concurrent utilization interesting, challenging, and, in the long run, beneficial. Unexpected consequences of parallelization have been discovered. It is possible to obtain reduced performance, both relative and absolute, from an increased number of processors, as a result of inappropriate use of resources in a multiprocessor environment. This exemplifies one of the paradoxes which result from our cultural bias towards sequential thought processes. As a consequence there is a bias for sequential styles of program development in a multiprocessor environment. The authors have learned that the problem of automatic optimization in compilation of parallel programs is computationally hard. Early hopes that automatic, optimal parallelization of sequentially conceived programs would be as achievable as earlier automatic vectorization had been, have been dashed. The authors lack the insights and folklore which are needed to develop useful methodologies and heuristics in the area of parallel computation. The authors are embarked on a voyage of exploration of this new territory, and the work described in this volume can provide helpful guidance. The authors have to explore fully the differences between distributed memory systems, shared memory systems, and combinations, as well as the relative applicability of SIMD and MIMD architectures. Based on the information obtained in such exploration, useful steps towards efficient utilization of many processors should become possible. This paper covers several areas: systems programming, parallel/language/programming systems, and applications programming.

  12. Efficient Parallel Kernel Solvers for Computational Fluid Dynamics Applications

    NASA Technical Reports Server (NTRS)

    Sun, Xian-He

    1997-01-01

    Distributed-memory parallel computers dominate today's parallel computing arena. These machines, such as Intel Paragon, IBM SP2, and Cray Origin2OO, have successfully delivered high performance computing power for solving some of the so-called "grand-challenge" problems. Despite initial success, parallel machines have not been widely accepted in production engineering environments due to the complexity of parallel programming. On a parallel computing system, a task has to be partitioned and distributed appropriately among processors to reduce communication cost and to attain load balance. More importantly, even with careful partitioning and mapping, the performance of an algorithm may still be unsatisfactory, since conventional sequential algorithms may be serial in nature and may not be implemented efficiently on parallel machines. In many cases, new algorithms have to be introduced to increase parallel performance. In order to achieve optimal performance, in addition to partitioning and mapping, a careful performance study should be conducted for a given application to find a good algorithm-machine combination. This process, however, is usually painful and elusive. The goal of this project is to design and develop efficient parallel algorithms for highly accurate Computational Fluid Dynamics (CFD) simulations and other engineering applications. The work plan is 1) developing highly accurate parallel numerical algorithms, 2) conduct preliminary testing to verify the effectiveness and potential of these algorithms, 3) incorporate newly developed algorithms into actual simulation packages. The work plan has well achieved. Two highly accurate, efficient Poisson solvers have been developed and tested based on two different approaches: (1) Adopting a mathematical geometry which has a better capacity to describe the fluid, (2) Using compact scheme to gain high order accuracy in numerical discretization. The previously developed Parallel Diagonal Dominant (PDD) algorithm

  13. Efficient parallel CFD-DEM simulations using OpenMP

    NASA Astrophysics Data System (ADS)

    Amritkar, Amit; Deb, Surya; Tafti, Danesh

    2014-01-01

    The paper describes parallelization strategies for the Discrete Element Method (DEM) used for simulating dense particulate systems coupled to Computational Fluid Dynamics (CFD). While the field equations of CFD are best parallelized by spatial domain decomposition techniques, the N-body particulate phase is best parallelized over the number of particles. When the two are coupled together, both modes are needed for efficient parallelization. It is shown that under these requirements, OpenMP thread based parallelization has advantages over MPI processes. Two representative examples, fairly typical of dense fluid-particulate systems are investigated, including the validation of the DEM-CFD and thermal-DEM implementation with experiments. Fluidized bed calculations are performed on beds with uniform particle loading, parallelized with MPI and OpenMP. It is shown that as the number of processing cores and the number of particles increase, the communication overhead of building ghost particle lists at processor boundaries dominates time to solution, and OpenMP which does not require this step is about twice as fast as MPI. In rotary kiln heat transfer calculations, which are characterized by spatially non-uniform particle distributions, the low overhead of switching the parallelization mode in OpenMP eliminates the load imbalances, but introduces increased overheads in fetching non-local data. In spite of this, it is shown that OpenMP is between 50-90% faster than MPI.

  14. Parallel processing in immune networks

    NASA Astrophysics Data System (ADS)

    Agliari, Elena; Barra, Adriano; Bartolucci, Silvia; Galluzzi, Andrea; Guerra, Francesco; Moauro, Francesco

    2013-04-01

    In this work, we adopt a statistical-mechanics approach to investigate basic, systemic features exhibited by adaptive immune systems. The lymphocyte network made by B cells and T cells is modeled by a bipartite spin glass, where, following biological prescriptions, links connecting B cells and T cells are sparse. Interestingly, the dilution performed on links is shown to make the system able to orchestrate parallel strategies to fight several pathogens at the same time; this multitasking capability constitutes a remarkable, key property of immune systems as multiple antigens are always present within the host. We also define the stochastic process ruling the temporal evolution of lymphocyte activity and show its relaxation toward an equilibrium measure allowing statistical-mechanics investigations. Analytical results are compared with Monte Carlo simulations and signal-to-noise outcomes showing overall excellent agreement. Finally, within our model, a rationale for the experimentally well-evidenced correlation between lymphocytosis and autoimmunity is achieved; this sheds further light on the systemic features exhibited by immune networks.

  15. Graphics applications utilizing parallel processing

    NASA Technical Reports Server (NTRS)

    Rice, John R.

    1990-01-01

    The results are presented of research conducted to develop a parallel graphic application algorithm to depict the numerical solution of the 1-D wave equation, the vibrating string. The research was conducted on a Flexible Flex/32 multiprocessor and a Sequent Balance 21000 multiprocessor. The wave equation is implemented using the finite difference method. The synchronization issues that arose from the parallel implementation and the strategies used to alleviate the effects of the synchronization overhead are discussed.

  16. Parallel Activation in Bilingual Phonological Processing

    ERIC Educational Resources Information Center

    Lee, Su-Yeon

    2011-01-01

    In bilingual language processing, the parallel activation hypothesis suggests that bilinguals activate their two languages simultaneously during language processing. Support for the parallel activation mainly comes from studies of lexical (word-form) processing, with relatively less attention to phonological (sound) processing. According to…

  17. Parallel processing of ADS40 images on PC network

    NASA Astrophysics Data System (ADS)

    Qiu, Feng; Duan, Yansong; Zhang, Jianqing

    2009-10-01

    In this paper, we aim to design a parallel processing system based on economic hardware environment to optimize photogrammetric process of Leica ADS40 images considering ideas and methods of parallel computing. We adopt parallel computing PCAM principle to design and implement a test system for parallel processing of ADS40 images. The test system consists of common personal computers and local gigabits network. It can make full use of network computing and storage resources under a economical and practical cost to deal with ADS40 images. Experiment shows that it achieves significant improvement of processing efficiency. Furthermore, the robustness and compatibility of this system is much higher than stand alone computer system because of system's redundancy based on network. In conclusion, parallel processing system based on PC network brings us a much more efficiency solution of ADS40's photogrammetric production.

  18. Efficient Parallel Engineering Computing on Linux Workstations

    NASA Technical Reports Server (NTRS)

    Lou, John Z.

    2010-01-01

    A C software module has been developed that creates lightweight processes (LWPs) dynamically to achieve parallel computing performance in a variety of engineering simulation and analysis applications to support NASA and DoD project tasks. The required interface between the module and the application it supports is simple, minimal and almost completely transparent to the user applications, and it can achieve nearly ideal computing speed-up on multi-CPU engineering workstations of all operating system platforms. The module can be integrated into an existing application (C, C++, Fortran and others) either as part of a compiled module or as a dynamically linked library (DLL).

  19. Bitplane Image Coding With Parallel Coefficient Processing.

    PubMed

    Auli-Llinas, Francesc; Enfedaque, Pablo; Moure, Juan C; Sanchez, Victor

    2016-01-01

    Image coding systems have been traditionally tailored for multiple instruction, multiple data (MIMD) computing. In general, they partition the (transformed) image in codeblocks that can be coded in the cores of MIMD-based processors. Each core executes a sequential flow of instructions to process the coefficients in the codeblock, independently and asynchronously from the others cores. Bitplane coding is a common strategy to code such data. Most of its mechanisms require sequential processing of the coefficients. The last years have seen the upraising of processing accelerators with enhanced computational performance and power efficiency whose architecture is mainly based on the single instruction, multiple data (SIMD) principle. SIMD computing refers to the execution of the same instruction to multiple data in a lockstep synchronous way. Unfortunately, current bitplane coding strategies cannot fully profit from such processors due to inherently sequential coding task. This paper presents bitplane image coding with parallel coefficient (BPC-PaCo) processing, a coding method that can process many coefficients within a codeblock in parallel and synchronously. To this end, the scanning order, the context formation, the probability model, and the arithmetic coder of the coding engine have been re-formulated. The experimental results suggest that the penalization in coding performance of BPC-PaCo with respect to the traditional strategies is almost negligible.

  20. Efficient Parallel Transaction Level Simulation by Exploiting Temporal Decoupling

    NASA Astrophysics Data System (ADS)

    Salimi Khaligh, Rauf; Radetzki, Martin

    In recent years, transaction level modeling (TLM) has enabled designers to simulate complex embedded systems and SoCs, orders of magnitude faster than simulation at the RTL. The increasing complexity of the systems on one hand, and availability of low cost parallel processing resources on the other hand have motivated the development of parallel simulation environments for TLMs. The existing simulation environments used for parallel simulation of TLMs are intended for general discrete event models and do not take advantage of the specific properties of TLMs. The fine-grain synchronization and communication between simulators in these environments can become a major impediment to the efficiency of the simulation environment. In this work, we exploit the properties of temporally decoupled TLMs to increase the efficiency of parallel simulation. Our approach does not require a special simulation kernel. We have implemented a parallel TLM simulation framework based on the publicly available OSCI SystemC simulator. The framework is based on the communication interfaces proposed in the recent OSCI TLM 2 standard. Our experimental results show the reduced synchronization overhead and improved simulation performance.

  1. Software For Diagnosis Of Parallel Processing

    NASA Technical Reports Server (NTRS)

    Hontalas, Philip; Yan, Jerry; Fineman, Charles

    1995-01-01

    Ames Instrumentation System (AIMS) computer program package of software tools measuring and analyzing performances of parallel-processing application programs. Helps programmer to debug and refine, and to monitor and visualize execution of, parallel-processing application software for Intel iPSC/860 (or equivalent) multicomputer. Performance data collected displayed graphically on computer workstations supporting X-Windows.

  2. An efficient parallel termination detection algorithm

    SciTech Connect

    Baker, A. H.; Crivelli, S.; Jessup, E. R.

    2004-05-27

    Information local to any one processor is insufficient to monitor the overall progress of most distributed computations. Typically, a second distributed computation for detecting termination of the main computation is necessary. In order to be a useful computational tool, the termination detection routine must operate concurrently with the main computation, adding minimal overhead, and it must promptly and correctly detect termination when it occurs. In this paper, we present a new algorithm for detecting the termination of a parallel computation on distributed-memory MIMD computers that satisfies all of those criteria. A variety of termination detection algorithms have been devised. Of these, the algorithm presented by Sinha, Kale, and Ramkumar (henceforth, the SKR algorithm) is unique in its ability to adapt to the load conditions of the system on which it runs, thereby minimizing the impact of termination detection on performance. Because their algorithm also detects termination quickly, we consider it to be the most efficient practical algorithm presently available. The termination detection algorithm presented here was developed for use in the PMESC programming library for distributed-memory MIMD computers. Like the SKR algorithm, our algorithm adapts to system loads and imposes little overhead. Also like the SKR algorithm, ours is tree-based, and it does not depend on any assumptions about the physical interconnection topology of the processors or the specifics of the distributed computation. In addition, our algorithm is easier to implement and requires only half as many tree traverses as does the SKR algorithm. This paper is organized as follows. In section 2, we define our computational model. In section 3, we review the SKR algorithm. We introduce our new algorithm in section 4, and prove its correctness in section 5. We discuss its efficiency and present experimental results in section 6.

  3. A note on parallel efficiency of fire simulation on cluster

    NASA Astrophysics Data System (ADS)

    Valasek, L.; Glasa, J.

    2016-08-01

    Current HPC clusters are capable to reduce execution time of parallelized tasks significantly. The paper discusses the use of two selected strategies of cluster computational resources allocation and their impact on parallel efficiency of fire simulation. Simulation of a simple corridor fire scenario by Fire Dynamics Simulator parallelized by the MPI programming model is tested on the HPC cluster at the Institute of Informatics of Slovak Academy of Sciences in Bratislava (Slovakia). The tests confirm that parallelization has a great potential to reduce execution times achieving promising values of parallel efficiency of the simulation, however, the results also show that the use of increasing numbers of computational meshes resulting in increasing numbers of used computational cores does not necessarily decrease the execution time nor the parallel efficiency of simulation. The results obtained indicate that the simulation achieves different values of the execution time and the parallel efficiency in regard of the used strategy for cluster computational resources allocation.

  4. Parallel processing for scientific computations

    NASA Technical Reports Server (NTRS)

    Alkhatib, Hasan S.

    1995-01-01

    The scope of this project dealt with the investigation of the requirements to support distributed computing of scientific computations over a cluster of cooperative workstations. Various experiments on computations for the solution of simultaneous linear equations were performed in the early phase of the project to gain experience in the general nature and requirements of scientific applications. A specification of a distributed integrated computing environment, DICE, based on a distributed shared memory communication paradigm has been developed and evaluated. The distributed shared memory model facilitates porting existing parallel algorithms that have been designed for shared memory multiprocessor systems to the new environment. The potential of this new environment is to provide supercomputing capability through the utilization of the aggregate power of workstations cooperating in a cluster interconnected via a local area network. Workstations, generally, do not have the computing power to tackle complex scientific applications, making them primarily useful for visualization, data reduction, and filtering as far as complex scientific applications are concerned. There is a tremendous amount of computing power that is left unused in a network of workstations. Very often a workstation is simply sitting idle on a desk. A set of tools can be developed to take advantage of this potential computing power to create a platform suitable for large scientific computations. The integration of several workstations into a logical cluster of distributed, cooperative, computing stations presents an alternative to shared memory multiprocessor systems. In this project we designed and evaluated such a system.

  5. Advanced parallel processing with supercomputer architectures

    SciTech Connect

    Hwang, K.

    1987-10-01

    This paper investigates advanced parallel processing techniques and innovative hardware/software architectures that can be applied to boost the performance of supercomputers. Critical issues on architectural choices, parallel languages, compiling techniques, resource management, concurrency control, programming environment, parallel algorithms, and performance enhancement methods are examined and the best answers are presented. The authors cover advanced processing techniques suitable for supercomputers, high-end mainframes, minisupers, and array processors. The coverage emphasizes vectorization, multitasking, multiprocessing, and distributed computing. In order to achieve these operation modes, parallel languages, smart compilers, synchronization mechanisms, load balancing methods, mapping parallel algorithms, operating system functions, application library, and multidiscipline interactions are investigated to ensure high performance. At the end, they assess the potentials of optical and neural technologies for developing future supercomputers.

  6. Parallel processing of numerical transport algorithms

    SciTech Connect

    Wienke, B.R.; Hiromoto, R.E.

    1984-01-01

    The multigroup, discrete ordinates representation for the linear transport equation enjoys widespread computational use and popularity. Serial solution schemes and numerical algorithms developed over the years provide a timely framework for parallel extension. On the Denelcor HEP, we investigate the parallel structure and extension of a number of standard S/sub n/ approaches. Concurrent inner sweeps, coupled acceleration techniques, synchronized inner-outer loops, and chaotic iteration are described, and results of computations are contrasted. The multigroup representation and serial iteration methods are also detailed. The basic iterative S/sub n/ method lends itself to parallel tasking, portably affording an effective medium for performing transport calculations on future architectures. This analysis represents a first attempt to extend serial S/sub n/ algorithms to parallel environments and provides good baseline estimates on ease of parallel implementation, relative algorithm efficiency, comparative speedup, and some future directions. We find basic inner-outer and chaotic iteration strategies both easily support comparably high degrees of parallelism. Both accommodate parallel rebalance and diffusion acceleration and appear as robust and viable parallel techniques for S/sub n/ production work.

  7. Computationally efficient implementation of combustion chemistry in parallel PDF calculations

    NASA Astrophysics Data System (ADS)

    Lu, Liuyan; Lantz, Steven R.; Ren, Zhuyin; Pope, Stephen B.

    2009-08-01

    In parallel calculations of combustion processes with realistic chemistry, the serial in situ adaptive tabulation (ISAT) algorithm [S.B. Pope, Computationally efficient implementation of combustion chemistry using in situ adaptive tabulation, Combustion Theory and Modelling, 1 (1997) 41-63; L. Lu, S.B. Pope, An improved algorithm for in situ adaptive tabulation, Journal of Computational Physics 228 (2009) 361-386] substantially speeds up the chemistry calculations on each processor. To improve the parallel efficiency of large ensembles of such calculations in parallel computations, in this work, the ISAT algorithm is extended to the multi-processor environment, with the aim of minimizing the wall clock time required for the whole ensemble. Parallel ISAT strategies are developed by combining the existing serial ISAT algorithm with different distribution strategies, namely purely local processing (PLP), uniformly random distribution (URAN), and preferential distribution (PREF). The distribution strategies enable the queued load redistribution of chemistry calculations among processors using message passing. They are implemented in the software x2f_mpi, which is a Fortran 95 library for facilitating many parallel evaluations of a general vector function. The relative performance of the parallel ISAT strategies is investigated in different computational regimes via the PDF calculations of multiple partially stirred reactors burning methane/air mixtures. The results show that the performance of ISAT with a fixed distribution strategy strongly depends on certain computational regimes, based on how much memory is available and how much overlap exists between tabulated information on different processors. No one fixed strategy consistently achieves good performance in all the regimes. Therefore, an adaptive distribution strategy, which blends PLP, URAN and PREF, is devised and implemented. It yields consistently good performance in all regimes. In the adaptive parallel

  8. Parallel processing of a rotating shaft simulation

    NASA Technical Reports Server (NTRS)

    Arpasi, Dale J.

    1989-01-01

    A FORTRAN program describing the vibration modes of a rotor-bearing system is analyzed for parellelism in this simulation using a Pascal-like structured language. Potential vector operations are also identified. A critical path through the simulation is identified and used in conjunction with somewhat fictitious processor characteristics to determine the time to calculate the problem on a parallel processing system having those characteristics. A parallel processing overhead time is included as a parameter for proper evaluation of the gain over serial calculation. The serial calculation time is determined for the same fictitious system. An improvement of up to 640 percent is possible depending on the value of the overhead time. Based on the analysis, certain conclusions are drawn pertaining to the development needs of parallel processing technology, and to the specification of parallel processing systems to meet computational needs.

  9. Efficient parallel simulation of CO2 geologic sequestration insaline aquifers

    SciTech Connect

    Zhang, Keni; Doughty, Christine; Wu, Yu-Shu; Pruess, Karsten

    2007-01-01

    An efficient parallel simulator for large-scale, long-termCO2 geologic sequestration in saline aquifers has been developed. Theparallel simulator is a three-dimensional, fully implicit model thatsolves large, sparse linear systems arising from discretization of thepartial differential equations for mass and energy balance in porous andfractured media. The simulator is based on the ECO2N module of the TOUGH2code and inherits all the process capabilities of the single-CPU TOUGH2code, including a comprehensive description of the thermodynamics andthermophysical properties of H2O-NaCl- CO2 mixtures, modeling singleand/or two-phase isothermal or non-isothermal flow processes, two-phasemixtures, fluid phases appearing or disappearing, as well as saltprecipitation or dissolution. The new parallel simulator uses MPI forparallel implementation, the METIS software package for simulation domainpartitioning, and the iterative parallel linear solver package Aztec forsolving linear equations by multiple processors. In addition, theparallel simulator has been implemented with an efficient communicationscheme. Test examples show that a linear or super-linear speedup can beobtained on Linux clusters as well as on supercomputers. Because of thesignificant improvement in both simulation time and memory requirement,the new simulator provides a powerful tool for tackling larger scale andmore complex problems than can be solved by single-CPU codes. Ahigh-resolution simulation example is presented that models buoyantconvection, induced by a small increase in brine density caused bydissolution of CO2.

  10. Parallel processing in finite element structural analysis

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K.

    1987-01-01

    A brief review is made of the fundamental concepts and basic issues of parallel processing. Discussion focuses on parallel numerical algorithms, performance evaluation of machines and algorithms, and parallelism in finite element computations. A computational strategy is proposed for maximizing the degree of parallelism at different levels of the finite element analysis process including: 1) formulation level (through the use of mixed finite element models); 2) analysis level (through additive decomposition of the different arrays in the governing equations into the contributions to a symmetrized response plus correction terms); 3) numerical algorithm level (through the use of operator splitting techniques and application of iterative processes); and 4) implementation level (through the effective combination of vectorization, multitasking and microtasking, whenever available).

  11. Endpoint-based parallel data processing in a parallel active messaging interface of a parallel computer

    DOEpatents

    Archer, Charles J.; Blocksome, Michael A.; Ratterman, Joseph D.; Smith, Brian E.

    2014-08-12

    Endpoint-based parallel data processing in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI composed of data communications endpoints, each endpoint including a specification of data communications parameters for a thread of execution on a compute node, including specifications of a client, a context, and a task, the compute nodes coupled for data communications through the PAMI, including establishing a data communications geometry, the geometry specifying, for tasks representing processes of execution of the parallel application, a set of endpoints that are used in collective operations of the PAMI including a plurality of endpoints for one of the tasks; receiving in endpoints of the geometry an instruction for a collective operation; and executing the instruction for a collective operation through the endpoints in dependence upon the geometry, including dividing data communications operations among the plurality of endpoints for one of the tasks.

  12. Endpoint-based parallel data processing in a parallel active messaging interface of a parallel computer

    DOEpatents

    Archer, Charles J; Blocksome, Michael E; Ratterman, Joseph D; Smith, Brian E

    2014-02-11

    Endpoint-based parallel data processing in a parallel active messaging interface ('PAMI') of a parallel computer, the PAMI composed of data communications endpoints, each endpoint including a specification of data communications parameters for a thread of execution on a compute node, including specifications of a client, a context, and a task, the compute nodes coupled for data communications through the PAMI, including establishing a data communications geometry, the geometry specifying, for tasks representing processes of execution of the parallel application, a set of endpoints that are used in collective operations of the PAMI including a plurality of endpoints for one of the tasks; receiving in endpoints of the geometry an instruction for a collective operation; and executing the instruction for a collective opeartion through the endpoints in dependence upon the geometry, including dividing data communications operations among the plurality of endpoints for one of the tasks.

  13. Extensions of ADA for SIMD parallel processing

    SciTech Connect

    Cline, C.; Siegel, H.J.

    1983-01-01

    In order to program SIMD (single instruction stream-multiple data stream) parallel machines used for tasks such as speech and image processing, a language with explicit parallel constructs is often desirable. The language ADA, developed by the Department of Defense, is used as a basis for such a language. Extensions of ADA which allow the user to specify such things as interprocessor communications and activation of processors are proposed. 25 references.

  14. FORTRAN Extensions for Modular Parallel Processing

    1996-01-12

    FORTRAN M is a small set of extensions to FORTRAN that supports a modular approach to the construction of sequential and parallel programs. FORTRAN M programs use channels to plug together processes which may be written in FORTRAN M or FORTRAN 77. Processes communicate by sending and receiving messages on channels. Channels and processes can be created dynamically, but programs remain deterministic unless specialized nondeterministic constructs are used.

  15. Casting pearls ballistically: Efficient massively parallel simulation of particle deposition

    SciTech Connect

    Lubachevsky, B.D.; Privman, V.; Roy, S.C.

    1996-06-01

    We simulate ballistic particle deposition wherein a large number of spherical particles are {open_quotes}cast{close_quotes} vertically over a planar horizontal surface. Upon first contact (with the surface or with a previously deposited particle) each particle stops. This model helps material scientists to study the adsorption and sediment formation. The model is sequential, with particles deposited one by one. We have found an equivalent formulation using a continuous time random process and we simulate the latter in parallel using a method similar to the one previously employed for simulating Ising spins. We augment the parallel algorithm for simulating Ising spins with several techniques aimed at the increase of efficiency of producing the particle configuration and statistics collection. Some of these techniques are similar to earlier ones. We implement the resulting algorithm on a 16K PE MasPar MP-1 and a 4K PE MasPar MP-2. The parallel code runs on MasPar computers nearly two orders of magnitude faster than an optimized sequential code runs on a fast workstation. 17 refs., 9 figs.

  16. Parallel and Serial Processes in Visual Search

    ERIC Educational Resources Information Center

    Thornton, Thomas L.; Gilden, David L.

    2007-01-01

    A long-standing issue in the study of how people acquire visual information centers around the scheduling and deployment of attentional resources: Is the process serial, or is it parallel? A substantial empirical effort has been dedicated to resolving this issue. However, the results remain largely inconclusive because the methodologies that have…

  17. Hypercluster parallel processing library user's manual

    NASA Technical Reports Server (NTRS)

    Quealy, Angela

    1990-01-01

    This User's Manual describes the Hypercluster Parallel Processing Library, composed of FORTRAN-callable subroutines which enable a FORTRAN programmer to manipulate and transfer information throughout the Hypercluster at NASA Lewis Research Center. Each subroutine and its parameters are described in detail. A simple heat flow application using Laplace's equation is included to demonstrate the use of some of the library's subroutines. The manual can be used initially as an introduction to the parallel features provided by the library. Thereafter it can be used as a reference when programming an application.

  18. Efficiency Evaluation of Cray XT Parallel IO Stack

    SciTech Connect

    Yu, Weikuan; Oral, H Sarp; Vetter, Jeffrey S; Barrett, Richard F

    2007-01-01

    PetaScale computing platforms need to be coupled with efficient IO subsystems that can deliver commensurate IO throughput to scientific applications. In order to gain insights into the deliverable IO efficiency on the Cray XT platform at ORNL, this paper presents an in-depth efficiency evaluation of its parallel IO software stack. Our evaluation covers the performance of a variety of parallel IO interfaces, including POSIX IO, MPI-IO, and HDF5. Moreover, we describe several tuning parameters for these interfaces and present their effectiveness in enhancing the IO efficiency.

  19. Parallel asynchronous systems and image processing algorithms

    NASA Technical Reports Server (NTRS)

    Coon, D. D.; Perera, A. G. U.

    1989-01-01

    A new hardware approach to implementation of image processing algorithms is described. The approach is based on silicon devices which would permit an independent analog processing channel to be dedicated to evey pixel. A laminar architecture consisting of a stack of planar arrays of the device would form a two-dimensional array processor with a 2-D array of inputs located directly behind a focal plane detector array. A 2-D image data stream would propagate in neuronlike asynchronous pulse coded form through the laminar processor. Such systems would integrate image acquisition and image processing. Acquisition and processing would be performed concurrently as in natural vision systems. The research is aimed at implementation of algorithms, such as the intensity dependent summation algorithm and pyramid processing structures, which are motivated by the operation of natural vision systems. Implementation of natural vision algorithms would benefit from the use of neuronlike information coding and the laminar, 2-D parallel, vision system type architecture. Besides providing a neural network framework for implementation of natural vision algorithms, a 2-D parallel approach could eliminate the serial bottleneck of conventional processing systems. Conversion to serial format would occur only after raw intensity data has been substantially processed. An interesting challenge arises from the fact that the mathematical formulation of natural vision algorithms does not specify the means of implementation, so that hardware implementation poses intriguing questions involving vision science.

  20. A parallel Jacobson-Oksman optimization algorithm. [parallel processing (computers)

    NASA Technical Reports Server (NTRS)

    Straeter, T. A.; Markos, A. T.

    1975-01-01

    A gradient-dependent optimization technique which exploits the vector-streaming or parallel-computing capabilities of some modern computers is presented. The algorithm, derived by assuming that the function to be minimized is homogeneous, is a modification of the Jacobson-Oksman serial minimization method. In addition to describing the algorithm, conditions insuring the convergence of the iterates of the algorithm and the results of numerical experiments on a group of sample test functions are presented. The results of these experiments indicate that this algorithm will solve optimization problems in less computing time than conventional serial methods on machines having vector-streaming or parallel-computing capabilities.

  1. High-speed parallel-processing networks for advanced architectures

    SciTech Connect

    Morgan, D.R.

    1988-06-01

    This paper describes various parallel-processing architecture networks that are candidates for eventual airborne use. An attempt at projecting which type of network is suitable or optimum for specific metafunction or stand-alone applications is made. However, specific algorithms will need to be developed and bench marks executed before firm conclusions can be drawn. Also, a conceptual projection of how these processors can be built in small, flyable units through the use of wafer-scale integration is offered. The use of the PAVE PILLAR system architecture to provide system level support for these tightly coupled networks is described. The author concludes that: (1) extremely high processing speeds implemented in flyable hardware is possible through parallel-processing networks if development programs are pursued; (2) dramatic speed enhancements through parallel processing requires an excellent match between the algorithm and computer-network architecture; (3) matching several high speed parallel oriented algorithms across the aircraft system to a limited set of hardware modules may be the most cost-effective approach to achieving speed enhancements; and (4) software-development tools and improved operating systems will need to be developed to support efficient parallel-processor use.

  2. Efficient sequential and parallel algorithms for record linkage

    PubMed Central

    Mamun, Abdullah-Al; Mi, Tian; Aseltine, Robert; Rajasekaran, Sanguthevar

    2014-01-01

    Background and objective Integrating data from multiple sources is a crucial and challenging problem. Even though there exist numerous algorithms for record linkage or deduplication, they suffer from either large time needs or restrictions on the number of datasets that they can integrate. In this paper we report efficient sequential and parallel algorithms for record linkage which handle any number of datasets and outperform previous algorithms. Methods Our algorithms employ hierarchical clustering algorithms as the basis. A key idea that we use is radix sorting on certain attributes to eliminate identical records before any further processing. Another novel idea is to form a graph that links similar records and find the connected components. Results Our sequential and parallel algorithms have been tested on a real dataset of 1 083 878 records and synthetic datasets ranging in size from 50 000 to 9 000 000 records. Our sequential algorithm runs at least two times faster, for any dataset, than the previous best-known algorithm, the two-phase algorithm using faster computation of the edit distance (TPA (FCED)). The speedups obtained by our parallel algorithm are almost linear. For example, we get a speedup of 7.5 with 8 cores (residing in a single node), 14.1 with 16 cores (residing in two nodes), and 26.4 with 32 cores (residing in four nodes). Conclusions We have compared the performance of our sequential algorithm with TPA (FCED) and found that our algorithm outperforms the previous one. The accuracy is the same as that of this previous best-known algorithm. PMID:24154837

  3. An efficient parallel algorithm for accelerating computational protein design

    PubMed Central

    Zhou, Yichao; Xu, Wei; Donald, Bruce R.; Zeng, Jianyang

    2014-01-01

    Motivation: Structure-based computational protein design (SCPR) is an important topic in protein engineering. Under the assumption of a rigid backbone and a finite set of discrete conformations of side-chains, various methods have been proposed to address this problem. A popular method is to combine the dead-end elimination (DEE) and A* tree search algorithms, which provably finds the global minimum energy conformation (GMEC) solution. Results: In this article, we improve the efficiency of computing A* heuristic functions for protein design and propose a variant of A* algorithm in which the search process can be performed on a single GPU in a massively parallel fashion. In addition, we make some efforts to address the memory exceeding problem in A* search. As a result, our enhancements can achieve a significant speedup of the A*-based protein design algorithm by four orders of magnitude on large-scale test data through pre-computation and parallelization, while still maintaining an acceptable memory overhead. We also show that our parallel A* search algorithm could be successfully combined with iMinDEE, a state-of-the-art DEE criterion, for rotamer pruning to further improve SCPR with the consideration of continuous side-chain flexibility. Availability: Our software is available and distributed open-source under the GNU Lesser General License Version 2.1 (GNU, February 1999). The source code can be downloaded from http://www.cs.duke.edu/donaldlab/osprey.php or http://iiis.tsinghua.edu.cn/∼compbio/software.html. Contact: zengjy321@tsinghua.edu.cn Supplementary information: Supplementary data are available at Bioinformatics online. PMID:24931991

  4. An Expert System for the Development of Efficient Parallel Code

    NASA Technical Reports Server (NTRS)

    Jost, Gabriele; Chun, Robert; Jin, Hao-Qiang; Labarta, Jesus; Gimenez, Judit

    2004-01-01

    We have built the prototype of an expert system to assist the user in the development of efficient parallel code. The system was integrated into the parallel programming environment that is currently being developed at NASA Ames. The expert system interfaces to tools for automatic parallelization and performance analysis. It uses static program structure information and performance data in order to automatically determine causes of poor performance and to make suggestions for improvements. In this paper we give an overview of our programming environment, describe the prototype implementation of our expert system, and demonstrate its usefulness with several case studies.

  5. A parallel processing VLSI BAM engine.

    PubMed

    Hasan, S R; Siong, N K

    1997-01-01

    In this paper emerging parallel/distributed architectures are explored for the digital VLSI implementation of adaptive bidirectional associative memory (BAM) neural network. A single instruction stream many data stream (SIMD)-based parallel processing architecture, is developed for the adaptive BAM neural network, taking advantage of the inherent parallelism in BAM. This novel neural processor architecture is named the sliding feeder BAM array processor (SLiFBAM). The SLiFBAM processor can be viewed as a two-stroke neural processing engine, It has four operating modes: learn pattern, evaluate pattern, read weight, and write weight. Design of a SLiFBAM VLSI processor chip is also described. By using 2-mum scalable CMOS technology, a SLiFBAM processor chip with 4+4 neurons and eight modules of 256x5 bit local weight-storage SRAM, was integrated on a 6.9x7.4 mm(2) prototype die. The system architecture is highly flexible and modular, enabling the construction of larger BAM networks of up to 252 neurons using multiple SLiFBAM chips.

  6. A multiarchitecture parallel-processing development environment

    NASA Technical Reports Server (NTRS)

    Townsend, Scott; Blech, Richard; Cole, Gary

    1993-01-01

    A description is given of the hardware and software of a multiprocessor test bed - the second generation Hypercluster system. The Hypercluster architecture consists of a standard hypercube distributed-memory topology, with multiprocessor shared-memory nodes. By using standard, off-the-shelf hardware, the system can be upgraded to use rapidly improving computer technology. The Hypercluster's multiarchitecture nature makes it suitable for researching parallel algorithms in computational field simulation applications (e.g., computational fluid dynamics). The dedicated test-bed environment of the Hypercluster and its custom-built software allows experiments with various parallel-processing concepts such as message passing algorithms, debugging tools, and computational 'steering'. Such research would be difficult, if not impossible, to achieve on shared, commercial systems.

  7. Oxytocin: parallel processing in the social brain?

    PubMed

    Dölen, Gül

    2015-06-01

    Early studies attempting to disentangle the network complexity of the brain exploited the accessibility of sensory receptive fields to reveal circuits made up of synapses connected both in series and in parallel. More recently, extension of this organisational principle beyond the sensory systems has been made possible by the advent of modern molecular, viral and optogenetic approaches. Here, evidence supporting parallel processing of social behaviours mediated by oxytocin is reviewed. Understanding oxytocinergic signalling from this perspective has significant implications for the design of oxytocin-based therapeutic interventions aimed at disorders such as autism, where disrupted social function is a core clinical feature. Moreover, identification of opportunities for novel technology development will require a better appreciation of the complexity of the circuit-level organisation of the social brain.

  8. Oxytocin: parallel processing in the social brain?

    PubMed

    Dölen, Gül

    2015-06-01

    Early studies attempting to disentangle the network complexity of the brain exploited the accessibility of sensory receptive fields to reveal circuits made up of synapses connected both in series and in parallel. More recently, extension of this organisational principle beyond the sensory systems has been made possible by the advent of modern molecular, viral and optogenetic approaches. Here, evidence supporting parallel processing of social behaviours mediated by oxytocin is reviewed. Understanding oxytocinergic signalling from this perspective has significant implications for the design of oxytocin-based therapeutic interventions aimed at disorders such as autism, where disrupted social function is a core clinical feature. Moreover, identification of opportunities for novel technology development will require a better appreciation of the complexity of the circuit-level organisation of the social brain. PMID:25912257

  9. Memory Scalability and Efficiency Analysis of Parallel Codes

    SciTech Connect

    Janjusic, Tommy; Kartsaklis, Christos

    2015-01-01

    Memory scalability is an enduring problem and bottleneck that plagues many parallel codes. Parallel codes designed for High Performance Systems are typically designed over the span of several, and in some instances 10+, years. As a result, optimization practices which were appropriate for earlier systems may no longer be valid and thus require careful optimization consideration. Specifically, parallel codes whose memory footprint is a function of their scalability must be carefully considered for future exa-scale systems. In this paper we present a methodology and tool to study the memory scalability of parallel codes. Using our methodology we evaluate an application s memory footprint as a function of scalability, which we coined memory efficiency, and describe our results. In particular, using our in-house tools we can pinpoint the specific application components which contribute to the application s overall memory foot-print (application data- structures, libraries, etc.).

  10. Parallel Processing Strategies of the Primate Visual System

    PubMed Central

    Nassi, Jonathan J.; Callaway, Edward M.

    2009-01-01

    Preface Incoming sensory information is sent to the brain along modality-specific channels corresponding to the five senses. Each of these channels further parses the incoming signals into parallel streams to provide a compact, efficient input to the brain. Ultimately, these parallel input signals must be elaborated upon and integrated within the cortex to provide a unified and coherent percept. Recent studies in the primate visual cortex have greatly contributed to our understanding of how this goal is accomplished. Multiple strategies including retinal tiling, hierarchical and parallel processing and modularity, defined spatially and by cell type-specific connectivity, are all used by the visual system to recover the rich detail of our visual surroundings. PMID:19352403

  11. Parallel processing for digital picture comparison

    NASA Technical Reports Server (NTRS)

    Cheng, H. D.; Kou, L. T.

    1987-01-01

    In picture processing an important problem is to identify two digital pictures of the same scene taken under different lighting conditions. This kind of problem can be found in remote sensing, satellite signal processing and the related areas. The identification can be done by transforming the gray levels so that the gray level histograms of the two pictures are closely matched. The transformation problem can be solved by using the packing method. Researchers propose a VLSI architecture consisting of m x n processing elements with extensive parallel and pipelining computation capabilities to speed up the transformation with the time complexity 0(max(m,n)), where m and n are the numbers of the gray levels of the input picture and the reference picture respectively. If using uniprocessor and a dynamic programming algorithm, the time complexity will be 0(m(3)xn). The algorithm partition problem, as an important issue in VLSI design, is discussed. Verification of the proposed architecture is also given.

  12. An efficient data dependence analysis for parallelizing compilers

    NASA Technical Reports Server (NTRS)

    Li, Zhiyuan; Yew, Pen-Chung; Zhu, Chuan-Qi

    1990-01-01

    A novel algorithm, called the lambda test, is presented for an efficient and accurate data dependence analysis of multidimensional array references. It extends the numerical methods to allow all dimensions of array references to be tested simultaneously. Hence, it combines the efficiency and the accuracy of the both approaches. This algorithm has been implemented in PARAFRASE, a FORTRAN program parallelization restructurer developed at the University of Illinois at Urbana-Champaign. Some experimental results are presented to show its effectiveness.

  13. The source of dual-task limitations: Serial or parallel processing of multiple response selections?

    PubMed Central

    Marois, René

    2014-01-01

    Although it is generally recognized that the concurrent performance of two tasks incurs costs, the sources of these dual-task costs remain controversial. The serial bottleneck model suggests that serial postponement of task performance in dual-task conditions results from a central stage of response selection that can only process one task at a time. Cognitive-control models, by contrast, propose that multiple response selections can proceed in parallel, but that serial processing of task performance is predominantly adopted because its processing efficiency is higher than that of parallel processing. In the present study, we empirically tested this proposition by examining whether parallel processing would occur when it was more efficient and financially rewarded. The results indicated that even when parallel processing was more efficient and was incentivized by financial reward, participants still failed to process tasks in parallel. We conclude that central information processing is limited by a serial bottleneck. PMID:23864266

  14. Parallel digital signal processing architectures for image processing

    NASA Astrophysics Data System (ADS)

    Kshirsagar, Shirish P.; Hartley, David A.; Harvey, David M.; Hobson, Clifford A.

    1994-10-01

    This paper describes research into a high speed image processing system using parallel digital signal processors for the processing of electro-optic images. The objective of the system is to reduce the processing time of non-contact type inspection problems including industrial and medical applications. A single processor can not deliver sufficient processing power required for the use of applications hence, a MIMD system is designed and constructed to enable fast processing of electro-optic images. The Texas Instruments TMS320C40 digital signal processor is used due to its high speed floating point CPU and the support for the parallel processing environment. A custom designed VISION bus is provided to transfer images between processors. The system is being applied for solder joint inspection of high technology printed circuit boards.

  15. Organizing Compression of Hyperspectral Imagery to Allow Efficient Parallel Decompression

    NASA Technical Reports Server (NTRS)

    Klimesh, Matthew A.; Kiely, Aaron B.

    2014-01-01

    family of schemes has been devised for organizing the output of an algorithm for predictive data compression of hyperspectral imagery so as to allow efficient parallelization in both the compressor and decompressor. In these schemes, the compressor performs a number of iterations, during each of which a portion of the data is compressed via parallel threads operating on independent portions of the data. The general idea is that for each iteration it is predetermined how much compressed data will be produced from each thread.

  16. A Parallel Processing Algorithm for Gravity Inversion

    NASA Astrophysics Data System (ADS)

    Frasheri, Neki; Bushati, Salvatore; Frasheri, Alfred

    2013-04-01

    The paper presents results of using MPI parallel processing for the 3D inversion of gravity anomalies. The work is done under the FP7 project HP-SEE (http://www.hp-see.eu/). The inversion of geophysical anomalies remains a challenge, and the use of parallel processing can be a tool to achieve better results, "compensating" the complexity of the ill-posed problem of inversion with the increase of volume of calculations. We considered the gravity as the simplest case of physical fields and experimented an algorithm based in the methodology known as CLEAN and developed by Högbom in 1974. The 3D geosection was discretized in finite cuboid elements and represented by a 3D array of nodes, while the ground surface where the anomaly is observed as a 2D array of points. Starting from a geosection with mass density zero in all nodes, iteratively the algorithm defines the 3D node that offers the best anomaly shape that approximates the observed anomaly minimizing the least squares error; the mass density in the best 3D node is modified with a prefixed density step and the related effect subtracted from the observed anomaly; the process continues until some criteria is fulfilled. Theoretical complexity of he algorithm was evaluated on the basis of iterations and run-time for a geosection discretized in different scales. We considered the average number N of nodes in one edge of the 3D array. The order of number of iterations was evaluated O(N^3); and the order of run-time was evaluated O(N^8). We used several different methods for the identification of the 3D node which effect offers the best least squares error in approximating the observed anomaly: unweighted least squares error for the whole 2D array of anomalous points; weighting least squares error by the inverted value of observed anomaly over each 3D node; and limiting the area of 2D anomalous points where least squares are calculated over shallow 3D nodes. By comparing results from the inversion of single body and two

  17. Enjoying Sad Music: Paradox or Parallel Processes?

    PubMed

    Schubert, Emery

    2016-01-01

    Enjoyment of negative emotions in music is seen by many as a paradox. This article argues that the paradox exists because it is difficult to view the process that generates enjoyment as being part of the same system that also generates the subjective negative feeling. Compensation theories explain the paradox as the compensation of a negative emotion by the concomitant presence of one or more positive emotions. But compensation brings us no closer to explaining the paradox because it does not explain how experiencing sadness itself is enjoyed. The solution proposed is that an emotion is determined by three critical processes-labeled motivational action tendency (MAT), subjective feeling (SF) and Appraisal. For many emotions the MAT and SF processes are coupled in valence. For example, happiness has positive MAT and positive SF, annoyance has negative MAT and negative SF. However, it is argued that in an aesthetic context, such as listening to music, emotion processes can become decoupled. The decoupling is controlled by the Appraisal process, which can assess if the context of the sadness is real-life (where coupling occurs) or aesthetic (where decoupling can occur). In an aesthetic context sadness retains its negative SF but the aversive, negative MAT is inhibited, leaving sadness to still be experienced as a negative valanced emotion, while contributing to the overall positive MAT. Individual differences, mood and previous experiences mediate the degree to which the aversive aspects of MAT are inhibited according to this Parallel Processing Hypothesis (PPH). The reason for hesitancy in considering or testing PPH, as well as the preponderance of research on sadness at the exclusion of other negative emotions, are discussed. PMID:27445752

  18. Enjoying Sad Music: Paradox or Parallel Processes?

    PubMed

    Schubert, Emery

    2016-01-01

    Enjoyment of negative emotions in music is seen by many as a paradox. This article argues that the paradox exists because it is difficult to view the process that generates enjoyment as being part of the same system that also generates the subjective negative feeling. Compensation theories explain the paradox as the compensation of a negative emotion by the concomitant presence of one or more positive emotions. But compensation brings us no closer to explaining the paradox because it does not explain how experiencing sadness itself is enjoyed. The solution proposed is that an emotion is determined by three critical processes-labeled motivational action tendency (MAT), subjective feeling (SF) and Appraisal. For many emotions the MAT and SF processes are coupled in valence. For example, happiness has positive MAT and positive SF, annoyance has negative MAT and negative SF. However, it is argued that in an aesthetic context, such as listening to music, emotion processes can become decoupled. The decoupling is controlled by the Appraisal process, which can assess if the context of the sadness is real-life (where coupling occurs) or aesthetic (where decoupling can occur). In an aesthetic context sadness retains its negative SF but the aversive, negative MAT is inhibited, leaving sadness to still be experienced as a negative valanced emotion, while contributing to the overall positive MAT. Individual differences, mood and previous experiences mediate the degree to which the aversive aspects of MAT are inhibited according to this Parallel Processing Hypothesis (PPH). The reason for hesitancy in considering or testing PPH, as well as the preponderance of research on sadness at the exclusion of other negative emotions, are discussed.

  19. Enjoying Sad Music: Paradox or Parallel Processes?

    PubMed Central

    Schubert, Emery

    2016-01-01

    Enjoyment of negative emotions in music is seen by many as a paradox. This article argues that the paradox exists because it is difficult to view the process that generates enjoyment as being part of the same system that also generates the subjective negative feeling. Compensation theories explain the paradox as the compensation of a negative emotion by the concomitant presence of one or more positive emotions. But compensation brings us no closer to explaining the paradox because it does not explain how experiencing sadness itself is enjoyed. The solution proposed is that an emotion is determined by three critical processes—labeled motivational action tendency (MAT), subjective feeling (SF) and Appraisal. For many emotions the MAT and SF processes are coupled in valence. For example, happiness has positive MAT and positive SF, annoyance has negative MAT and negative SF. However, it is argued that in an aesthetic context, such as listening to music, emotion processes can become decoupled. The decoupling is controlled by the Appraisal process, which can assess if the context of the sadness is real-life (where coupling occurs) or aesthetic (where decoupling can occur). In an aesthetic context sadness retains its negative SF but the aversive, negative MAT is inhibited, leaving sadness to still be experienced as a negative valanced emotion, while contributing to the overall positive MAT. Individual differences, mood and previous experiences mediate the degree to which the aversive aspects of MAT are inhibited according to this Parallel Processing Hypothesis (PPH). The reason for hesitancy in considering or testing PPH, as well as the preponderance of research on sadness at the exclusion of other negative emotions, are discussed. PMID:27445752

  20. Communication-efficient parallel-graph algorithms. Master's thesis

    SciTech Connect

    Maggs, B.M.

    1986-06-01

    Communication bandwidth is a resource ignored by most parallel random-access machine (PRAM) models. This thesis shows that many graph problems can be solved in parallel, not only with polylogarithmic performance, but with efficient communication at each step of the computation. The communication requirements of an algorithm are measured in a restricted PRAM model called the distributed random-access machine (DRAM), which can be viewed as an abstraction of volume-universal networks such as fat trees. In this model, communication cost is measured in terms of the congestion of memory accesses across cuts of the machine. It is demonstrated that the recursive doubling technique frequently used in PRAM algorithms is wasteful of communication resources, and that recursive pairing can be used to perform many of the same functions more efficiently. The prefix computation is generalized on linear lists to trees and show that these tree-fix computations, which can be performed in a communication-efficient fashion using a variant of the tree-contraction technique of Miller and Reif, simplify many parallel graph algorithms in the literature.

  1. Serial Order: A Parallel Distributed Processing Approach.

    ERIC Educational Resources Information Center

    Jordan, Michael I.

    Human behavior shows a variety of serially ordered action sequences. This paper presents a theory of serial order which describes how sequences of actions might be learned and performed. In this theory, parallel interactions across time (coarticulation) and parallel interactions across space (dual-task interference) are viewed as two aspects of a…

  2. Development and Applications of a Modular Parallel Process for Large Scale Fluid/Structures Problems

    NASA Technical Reports Server (NTRS)

    Guruswamy, Guru P.; Byun, Chansup; Kwak, Dochan (Technical Monitor)

    2001-01-01

    A modular process that can efficiently solve large scale multidisciplinary problems using massively parallel super computers is presented. The process integrates disciplines with diverse physical characteristics by retaining the efficiency of individual disciplines. Computational domain independence of individual disciplines is maintained using a meta programming approach. The process integrates disciplines without affecting the combined performance. Results are demonstrated for large scale aerospace problems on several supercomputers. The super scalability and portability of the approach is demonstrated on several parallel computers.

  3. Development and Applications of a Modular Parallel Process for Large Scale Fluid/Structures Problems

    NASA Technical Reports Server (NTRS)

    Guruswamy, Guru P.; Kwak, Dochan (Technical Monitor)

    2002-01-01

    A modular process that can efficiently solve large scale multidisciplinary problems using massively parallel supercomputers is presented. The process integrates disciplines with diverse physical characteristics by retaining the efficiency of individual disciplines. Computational domain independence of individual disciplines is maintained using a meta programming approach. The process integrates disciplines without affecting the combined performance. Results are demonstrated for large scale aerospace problems on several supercomputers. The super scalability and portability of the approach is demonstrated on several parallel computers.

  4. An intelligent allocation algorithm for parallel processing

    NASA Technical Reports Server (NTRS)

    Carroll, Chester C.; Homaifar, Abdollah; Ananthram, Kishan G.

    1988-01-01

    The problem of allocating nodes of a program graph to processors in a parallel processing architecture is considered. The algorithm is based on critical path analysis, some allocation heuristics, and the execution granularity of nodes in a program graph. These factors, and the structure of interprocessor communication network, influence the allocation. To achieve realistic estimations of the executive durations of allocations, the algorithm considers the fact that nodes in a program graph have to communicate through varying numbers of tokens. Coarse and fine granularities have been implemented, with interprocessor token-communication duration, varying from zero up to values comparable to the execution durations of individual nodes. The effect on allocation of communication network structures is demonstrated by performing allocations for crossbar (non-blocking) and star (blocking) networks. The algorithm assumes the availability of as many processors as it needs for the optimal allocation of any program graph. Hence, the focus of allocation has been on varying token-communication durations rather than varying the number of processors. The algorithm always utilizes as many processors as necessary for the optimal allocation of any program graph, depending upon granularity and characteristics of the interprocessor communication network.

  5. Fault tolerant massively parallel processing architecture

    SciTech Connect

    Balasubramanian, V.; Banerjee, P.

    1987-08-01

    This paper presents two massively parallel processing architectures suitable for solving a wide variety of algorithms of divide-and-conquer type for problems such as the discrete Fourier transform, production systems, design automation, and others. The first architecture, called the Chain-structured Butterfly ARchitecture (CBAR), consists of a two-dimensional array of N-L . (log/sub 2/(L)+1) processing elements (PE) organized as L levels of log/sub 2/(L)+1 stages, and which has the butterfly connection between PEs in consecutive stages with straight-through feedback between PEs in the last and first stages. This connection system has the desirable property of allowing thousands of PEs to be connected with O(N) connection cost, O(log/sub 2/(N/log/sub 2/N)) communication paths, and a small number (=4) of I/O ports per PE. However, this architecture is not fault tolerant. The authors, therefore, propose a second architecture, called the REconfigurable Chain-structured Butterfly ARchitecture (RECBAR), which is a modified version of the CBAR. The RECBAR possesses all the desirable features of the CBAR, with the number of I/O ports per PE increased to six, and uses O(log/sub 2/N)/N) overhead in PEs and approximately 50% overhead in links to achieve single-level fault tolerance. Reliability improvements of the RECBAR over the CBAR are studied. This paper also presents a distributed diagnostic and structuring algorithm for the RECBAR that enables the architecture to detect faults and structure itself accordingly within 2 . log/sub 2/(L)+1 time steps, thus making it a truly fault tolerant architecture.

  6. Programming Probabilistic Structural Analysis for Parallel Processing Computer

    NASA Technical Reports Server (NTRS)

    Sues, Robert H.; Chen, Heh-Chyun; Twisdale, Lawrence A.; Chamis, Christos C.; Murthy, Pappu L. N.

    1991-01-01

    The ultimate goal of this research program is to make Probabilistic Structural Analysis (PSA) computationally efficient and hence practical for the design environment by achieving large scale parallelism. The paper identifies the multiple levels of parallelism in PSA, identifies methodologies for exploiting this parallelism, describes the development of a parallel stochastic finite element code, and presents results of two example applications. It is demonstrated that speeds within five percent of those theoretically possible can be achieved. A special-purpose numerical technique, the stochastic preconditioned conjugate gradient method, is also presented and demonstrated to be extremely efficient for certain classes of PSA problems.

  7. Parallel Processing with Digital Signal Processing Hardware and Software

    NASA Technical Reports Server (NTRS)

    Swenson, Cory V.

    1995-01-01

    The assembling and testing of a parallel processing system is described which will allow a user to move a Digital Signal Processing (DSP) application from the design stage to the execution/analysis stage through the use of several software tools and hardware devices. The system will be used to demonstrate the feasibility of the Algorithm To Architecture Mapping Model (ATAMM) dataflow paradigm for static multiprocessor solutions of DSP applications. The individual components comprising the system are described followed by the installation procedure, research topics, and initial program development.

  8. Efficiently modeling neural networks on massively parallel computers

    SciTech Connect

    Farber, R.M.

    1992-01-01

    Neural networks are a very useful tool for analyzing and modeling complex real world systems. Applying neural network simulations to real world problems generally involves large amounts of data and massive amounts of computation. To efficiently handle the computational requirements of large problems, we have implemented at Los Alamos a highly efficient neural network compiler for serial computers, vector computers, vector parallel computers, and fine grain SIMD computers such as the CM-2 connection machine. This paper will describe the mapping used by the compiler to implement feed-forward backpropagation neural networks for a SIMD architecture parallel computer. Thinking Machines Corporation has benchmarked our code at 1.3 billion interconnects per second (approximately 3 gigaflops) on a 64,000 processor CM-2 connection machine (Singer 1990). This mapping is applicable to other SMM computers and can be implemented on computers such as the CM-5 connection machine. Our mapping has virtually no communications overhead with the exception of the communications required for a global summation across the processors. We can efficiently model very large neural networks which have many neurons and interconnects and our mapping can be extend to arbitrarily large networks by merging the memory space of separate processors with fast adjacent processor inter-processor communications. This paper will consider the simulation of only feed forward neural network although this method is extendible to recurrent networks.

  9. Efficiently modeling neural networks on massively parallel computers

    SciTech Connect

    Farber, R.M.

    1992-12-01

    Neural networks are a very useful tool for analyzing and modeling complex real world systems. Applying neural network simulations to real world problems generally involves large amounts of data and massive amounts of computation. To efficiently handle the computational requirements of large problems, we have implemented at Los Alamos a highly efficient neural network compiler for serial computers, vector computers, vector parallel computers, and fine grain SIMD computers such as the CM-2 connection machine. This paper will describe the mapping used by the compiler to implement feed-forward backpropagation neural networks for a SIMD architecture parallel computer. Thinking Machines Corporation has benchmarked our code at 1.3 billion interconnects per second (approximately 3 gigaflops) on a 64,000 processor CM-2 connection machine (Singer 1990). This mapping is applicable to other SMM computers and can be implemented on computers such as the CM-5 connection machine. Our mapping has virtually no communications overhead with the exception of the communications required for a global summation across the processors. We can efficiently model very large neural networks which have many neurons and interconnects and our mapping can be extend to arbitrarily large networks by merging the memory space of separate processors with fast adjacent processor inter-processor communications. This paper will consider the simulation of only feed forward neural network although this method is extendible to recurrent networks.

  10. Efficiently modeling neural networks on massively parallel computers

    NASA Technical Reports Server (NTRS)

    Farber, Robert M.

    1993-01-01

    Neural networks are a very useful tool for analyzing and modeling complex real world systems. Applying neural network simulations to real world problems generally involves large amounts of data and massive amounts of computation. To efficiently handle the computational requirements of large problems, we have implemented at Los Alamos a highly efficient neural network compiler for serial computers, vector computers, vector parallel computers, and fine grain SIMD computers such as the CM-2 connection machine. This paper describes the mapping used by the compiler to implement feed-forward backpropagation neural networks for a SIMD (Single Instruction Multiple Data) architecture parallel computer. Thinking Machines Corporation has benchmarked our code at 1.3 billion interconnects per second (approximately 3 gigaflops) on a 64,000 processor CM-2 connection machine (Singer 1990). This mapping is applicable to other SIMD computers and can be implemented on MIMD computers such as the CM-5 connection machine. Our mapping has virtually no communications overhead with the exception of the communications required for a global summation across the processors (which has a sub-linear runtime growth on the order of O(log(number of processors)). We can efficiently model very large neural networks which have many neurons and interconnects and our mapping can extend to arbitrarily large networks (within memory limitations) by merging the memory space of separate processors with fast adjacent processor interprocessor communications. This paper will consider the simulation of only feed forward neural network although this method is extendable to recurrent networks.

  11. Experience in highly parallel processing using DAP

    NASA Technical Reports Server (NTRS)

    Parkinson, D.

    1987-01-01

    Distributed Array Processors (DAP) have been in day to day use for ten years and a large amount of user experience has been gained. The profile of user applications is similar to that of the Massively Parallel Processor (MPP) working group. Experience has shown that contrary to expectations, highly parallel systems provide excellent performance on so-called dirty problems such as the physics part of meteorological codes. The reasons for this observation are discussed. The arguments against replacing bit processors with floating point processors are also discussed.

  12. Controlled loading of oligodeoxyribonucleotide monolayers onto unoxidized crystalline silicon; fluorescence-based determination of the surface coverage and of the hybridization efficiency; parallel imaging of the process by Atomic Force Microscopy

    PubMed Central

    Cattaruzza, Fabrizio; Cricenti, Antonio; Flamini, Alberto; Girasole, Marco; Longo, Giovanni; Prosperi, Tommaso; Andreano, Giuseppina; Cellai, Luciano; Chirivino, Emanuele

    2006-01-01

    Unoxidized crystalline silicon, characterized by high purity, high homogeneity, sturdiness and an atomically flat surface, offers many advantages for the construction of electronic miniaturized biosensor arrays upon attachment of biomolecules (DNA, proteins or small organic compounds). This allows to study the incidence of molecular interactions through the simultaneous analysis, within a single experiment, of a number of samples containing small quantities of potential targets, in the presence of thousands of variables. A simple, accurate and robust methodology was established and is here presented, for the assembling of DNA sensors on the unoxidized, crystalline Si(100) surface, by loading controlled amounts of a monolayer DNA-probe through a two-step procedure. At first a monolayer of a spacer molecule, such as 10-undecynoic acid, was deposited, under optimized conditions, via controlled cathodic electrografting, then a synthetic DNA-probe was anchored to it, through amidation in aqueous solution. The surface coverage of several DNA-probes and the control of their efficiency in recognizing a complementary target-DNA upon hybridization were evaluated by fluorescence measurements. The whole process was also monitored in parallel by Atomic Force Microscopy (AFM). PMID:16507670

  13. Parallel Processing in Visual Search Asymmetry

    ERIC Educational Resources Information Center

    Dosher, Barbara Anne; Han, Songmei; Lu, Zhong-Lin

    2004-01-01

    The difficulty of visual search may depend on assignment of the same visual elements as targets and distractors-search asymmetry. Easy C-in-O searches and difficult O-in-C searches are often associated with parallel and serial search, respectively. Here, the time course of visual search was measured for both tasks with speed-accuracy methods. The…

  14. Parallel-META: efficient metagenomic data analysis based on high-performance computation

    PubMed Central

    2012-01-01

    Background Metagenomics method directly sequences and analyses genome information from microbial communities. There are usually more than hundreds of genomes from different microbial species in the same community, and the main computational tasks for metagenomic data analyses include taxonomical and functional component examination of all genomes in the microbial community. Metagenomic data analysis is both data- and computation- intensive, which requires extensive computational power. Most of the current metagenomic data analysis softwares were designed to be used on a single computer or single computer clusters, which could not match with the fast increasing number of large metagenomic projects' computational requirements. Therefore, advanced computational methods and pipelines have to be developed to cope with such need for efficient analyses. Result In this paper, we proposed Parallel-META, a GPU- and multi-core-CPU-based open-source pipeline for metagenomic data analysis, which enabled the efficient and parallel analysis of multiple metagenomic datasets and the visualization of the results for multiple samples. In Parallel-META, the similarity-based database search was parallelized based on GPU computing and multi-core CPU computing optimization. Experiments have shown that Parallel-META has at least 15 times speed-up compared to traditional metagenomic data analysis method, with the same accuracy of the results http://www.computationalbioenergy.org/parallel-meta.html. Conclusion The parallel processing of current metagenomic data would be very promising: with current speed up of 15 times and above, binning would not be a very time-consuming process any more. Therefore, some deeper analysis of the metagenomic data, such as the comparison of different samples, would be feasible in the pipeline, and some of these functionalities have been included into the Parallel-META pipeline. PMID:23046922

  15. Parallel approach to incorporating face image information into dialogue processing

    NASA Astrophysics Data System (ADS)

    Ren, Fuji

    2000-10-01

    There are many kinds of so-called irregular expressions in natural dialogues. Even if the content of a conversation is the same in words, different meanings can be interpreted by a person's feeling or face expression. To have a good understanding of dialogues, it is required in a flexible dialogue processing system to infer the speaker's view properly. However, it is difficult to obtain the meaning of the speaker's sentences in various scenes using traditional methods. In this paper, a new approach for dialogue processing that incorporates information from the speaker's face is presented. We first divide conversation statements into several simple tasks. Second, we process each simple task using an independent processor. Third, we employ some speaker's face information to estimate the view of the speakers to solve ambiguities in dialogues. The approach presented in this paper can work efficiently, because independent processors run in parallel, writing partial results to a shared memory, incorporating partial results at appropriate points, and complementing each other. A parallel algorithm and a method for employing the face information in a dialogue machine translation will be discussed, and some results will be included in this paper.

  16. Extraction of Hydrological Proximity Measures from DEMs using Parallel Processing

    SciTech Connect

    Tesfa, Teklu K.; Tarboton, David G.; Watson, Daniel W.; Schreuders, Kimberly A.; Baker, Matthew M.; Wallace, Robert M.

    2011-12-01

    queue data structure to order the processing of cells so that each cell is visited only once and the cross-process communications that are a standard part of MPI are handled in an efficient manner. This parallel approach allows analysis of much larger DEMs as compared to the serial recursive algorithms. In this paper, we present the definitions of the HPMs, the serial and parallel algorithms used in their extraction and their potential applications in hydrology, geomorphology and ecology.

  17. Parallel versus Sequential Processing of Pictures and Words

    ERIC Educational Resources Information Center

    Snodgrass, Joan Gay; Antone, George

    1974-01-01

    The purpose of this experiment was to test a proposal by Paivio (1971) that visual memory images are specialized for parallel or spatiol processing, whereas verbal memory codes are specialized for sequential or temporal processing. (Author)

  18. Hypercluster - Parallel processing for computational mechanics

    NASA Technical Reports Server (NTRS)

    Blech, Richard A.

    1988-01-01

    An account is given of the development status, performance capabilities and implications for further development of NASA-Lewis' testbed 'hypercluster' parallel computer network, in which multiple processors communicate through a shared memory. Processors have local as well as shared memory; the hypercluster is expanded in the same manner as the hypercube, with processor clusters replacing the normal single processor node. The NASA-Lewis machine has three nodes with a vector personality and one node with a scalar personality. Each of the vector nodes uses four board-level vector processors, while the scalar node uses four general-purpose microcomputer boards.

  19. Bipartite memory network architectures for parallel processing

    SciTech Connect

    Smith, W.; Kale, L.V. . Dept. of Computer Science)

    1990-01-01

    Parallel architectures are boradly classified as either shared memory or distributed memory architectures. In this paper, the authors propose a third family of architectures, called bipartite memory network architectures. In this architecture, processors and memory modules constitute a bipartite graph, where each processor is allowed to access a small subset of the memory modules, and each memory module allows access from a small set of processors. The architecture is particularly suitable for computations requiring dynamic load balancing. The authors explore the properties of this architecture by examining the Perfect Difference set based topology for the graph. Extensions of this topology are also suggested.

  20. Efficient parallel algorithms for string editing and related problems

    NASA Technical Reports Server (NTRS)

    Apostolico, Alberto; Atallah, Mikhail J.; Larmore, Lawrence; Mcfaddin, H. S.

    1988-01-01

    The string editing problem for input strings x and y consists of transforming x into y by performing a series of weighted edit operations on x of overall minimum cost. An edit operation on x can be the deletion of a symbol from x, the insertion of a symbol in x or the substitution of a symbol x with another symbol. This problem has a well known O((absolute value of x)(absolute value of y)) time sequential solution (25). The efficient Program Requirements Analysis Methods (PRAM) parallel algorithms for the string editing problem are given. If m = ((absolute value of x),(absolute value of y)) and n = max((absolute value of x),(absolute value of y)), then the CREW bound is O (log m log n) time with O (mn/log m) processors. In all algorithms, space is O (mn).

  1. ENERGY EFFICIENT LAUNDRY PROCESS

    SciTech Connect

    Tim Richter

    2005-04-01

    With the rising cost of energy and increased concerns for pollution and greenhouse gas emissions from power generation, increased focus is being put on energy efficiency. This study looks at several approaches to reducing energy consumption in clothes care appliances by considering the appliances and laundry chemistry as a system, rather than individually.

  2. Parafrase restructuring of FORTRAN code for parallel processing

    NASA Technical Reports Server (NTRS)

    Wadhwa, Atul

    1988-01-01

    Parafrase transforms a FORTRAN code, subroutine by subroutine, into a parallel code for a vector and/or shared-memory multiprocessor system. Parafrase is not a compiler; it transforms a code and provides information for a vector or concurrent process. Parafrase uses a data dependency to reveal parallelism among instructions. The data dependency test distinguishes between recurrences and statements that can be directly vectorized or parallelized. A number of transformations are required to build a data dependency graph.

  3. Parallel processing research in the former Soviet Union

    SciTech Connect

    Dongarra, J.J.; Snyder, L.; Wolcott, P.

    1992-03-01

    This technical assessment report examines strengths and weaknesses of parallel processing research and development in the Soviet Union from the 1980s to June 1991. The assessment was carried out by panel of US scientists who are experts on parallel processing hardware, software, algorithms, and applications, and on Soviet computing. Soviet computer research and development organizations have pursued many of the major avenues of inquiry related to parallel processing that the West has chosen to explore. But, the limited size and substantial breadth of their effort have limited the collective depth of Soviet activity. Even more serious limitations (and delays) of Soviet achievement in parallel processing research can be traced to shortcomings of the Soviet computer industry, which was unable to supply adequate, reliable computer components. Without the ability to build, demonstrate, and test embodiments of their ideas in actual high-performance parallel hardware, both the scope of activity and the success of Soviet parallel processing researchers were severely limited. The quality of the Soviet parallel processing research assessed varied from very sound and interesting to pedestrian, with most of the groups at the major hardware and software centers to which the work is largely confined doing good (or at least serious) research. In a few instances, interesting and competent parallel language development work was found at institutions not associated with hardware development efforts. Unlike Soviet mainframe and minicomputer developers, Soviet parallel processing researchers have not concentrated their efforts on reverse- engineering specific Western systems. No evidence was found of successful Soviet attempts to use breakthroughs in parallel processing technology to leapfrog'' impediments and limitations that Soviet industrial weakness in microelectronics and other computer manufacturing areas impose on the performance of high-end Soviet computers.

  4. Parallel processing research in the former Soviet Union

    SciTech Connect

    Dongarra, J.J.; Snyder, L.; Wolcott, P.

    1992-03-01

    This technical assessment report examines strengths and weaknesses of parallel processing research and development in the Soviet Union from the 1980s to June 1991. The assessment was carried out by panel of US scientists who are experts on parallel processing hardware, software, algorithms, and applications, and on Soviet computing. Soviet computer research and development organizations have pursued many of the major avenues of inquiry related to parallel processing that the West has chosen to explore. But, the limited size and substantial breadth of their effort have limited the collective depth of Soviet activity. Even more serious limitations (and delays) of Soviet achievement in parallel processing research can be traced to shortcomings of the Soviet computer industry, which was unable to supply adequate, reliable computer components. Without the ability to build, demonstrate, and test embodiments of their ideas in actual high-performance parallel hardware, both the scope of activity and the success of Soviet parallel processing researchers were severely limited. The quality of the Soviet parallel processing research assessed varied from very sound and interesting to pedestrian, with most of the groups at the major hardware and software centers to which the work is largely confined doing good (or at least serious) research. In a few instances, interesting and competent parallel language development work was found at institutions not associated with hardware development efforts. Unlike Soviet mainframe and minicomputer developers, Soviet parallel processing researchers have not concentrated their efforts on reverse- engineering specific Western systems. No evidence was found of successful Soviet attempts to use breakthroughs in parallel processing technology to ``leapfrog`` impediments and limitations that Soviet industrial weakness in microelectronics and other computer manufacturing areas impose on the performance of high-end Soviet computers.

  5. [CMACPAR an modified parallel neuro-controller for control processes].

    PubMed

    Ramos, E; Surós, R

    1999-01-01

    CMACPAR is a Parallel Neurocontroller oriented to real time systems as for example Control Processes. Its characteristics are mainly a fast learning algorithm, a reduced number of calculations, great generalization capacity, local learning and intrinsic parallelism. This type of neurocontroller is used in real time applications required by refineries, hydroelectric centers, factories, etc. In this work we present the analysis and the parallel implementation of a modified scheme of the Cerebellar Model CMAC for the n-dimensional space projection using a mean granularity parallel neurocontroller. The proposed memory management allows for a significant memory reduction in training time and required memory size.

  6. Multiple-spot parallel processing for laser micronanofabrication

    NASA Astrophysics Data System (ADS)

    Kato, Jun-ichi; Takeyasu, Nobuyuki; Adachi, Yoshihiro; Sun, Hong-Bo; Kawata, Satoshi

    2005-01-01

    A tightly focused femtosecond laser has been established as a unique tool for micronanostructure fabrication due to its intrinsic three-dimensional processing. In this letter, we utilize a microlens array to produce multiple spots for parallel fabrication, giving rise to a revolutionary augmentation for our previously developed single-beam two-photon photopolymerization technology [S. Kawata, H.-B. Sun, T. Tanaka, and K. Takada, Nature (London) 412, 697 (2001)]. Two- and three-dimensional multiple structures, such as microletter set and self-standing microspring array, are demonstrated as examples of mass production. More than 200 spot simultaneous fabrication has been realized by optimizing the exposure condition for the photopolymerizable resin, i.e., a two-order increase of yield efficiency. Potential applications of this technique are discussed.

  7. An Airborne Onboard Parallel Processing Testbed

    NASA Technical Reports Server (NTRS)

    Mandl, Daniel J.

    2014-01-01

    This presentation provides information on the progress the Intelligent Payload Module (IPM) development effort. In addition, a vision is presented on integration of the IPM architecture with the GeoSocial Application Program Interface (API) architecture to enable efficient distribution of satellite data products.

  8. Roadmap for efficient parallelization of breast anatomy simulation

    NASA Astrophysics Data System (ADS)

    Chui, Joseph H.; Pokrajac, David D.; Maidment, Andrew D. A.; Bakic, Predrag R.

    2012-03-01

    A roadmap has been proposed to optimize the simulation of breast anatomy by parallel implementation, in order to reduce the time needed to generate software breast phantoms. The rapid generation of high resolution phantoms is needed to support virtual clinical trials of breast imaging systems. We have recently developed an octree-based recursive partitioning algorithm for breast anatomy simulation. The algorithm has good asymptotic complexity; however, its current MATLAB implementation cannot provide optimal execution times. The proposed roadmap for efficient parallelization includes the following steps: (i) migrate the current code to a C/C++ platform and optimize it for single-threaded implementation; (ii) modify the code to allow for multi-threaded CPU implementation; (iii) identify and migrate the code to a platform designed for multithreaded GPU implementation. In this paper, we describe our results in optimizing the C/C++ code for single-threaded and multi-threaded CPU implementations. As the first step of the proposed roadmap we have identified a bottleneck component in the MATLAB implementation using MATLAB's profiling tool, and created a single threaded CPU implementation of the algorithm using C/C++'s overloaded operators and standard template library. The C/C++ implementation has been compared to the MATLAB version in terms of accuracy and simulation time. A 520-fold reduction of the execution time was observed in a test of phantoms with 50- 400 μm voxels. In addition, we have identified several places in the code which will be modified to allow for the next roadmap milestone of the multithreaded CPU implementation.

  9. Time dependent processing in a parallel pipeline architecture.

    PubMed

    Biddiscombe, John; Geveci, Berk; Martin, Ken; Moreland, Kenneth; Thompson, David

    2007-01-01

    Pipeline architectures provide a versatile and efficient mechanism for constructing visualizations, and they have been implemented in numerous libraries and applications over the past two decades. In addition to allowing developers and users to freely combine algorithms, visualization pipelines have proven to work well when streaming data and scale well on parallel distributed-memory computers. However, current pipeline visualization frameworks have a critical flaw: they are unable to manage time varying data. As data flows through the pipeline, each algorithm has access to only a single snapshot in time of the data. This prevents the implementation of algorithms that do any temporal processing such as particle tracing; plotting over time; or interpolation, fitting, or smoothing of time series data. As data acquisition technology improves, as simulation time-integration techniques become more complex, and as simulations save less frequently and regularly, the ability to analyze the time-behavior of data becomes more important. This paper describes a modification to the traditional pipeline architecture that allows it to accommodate temporal algorithms. Furthermore, the architecture allows temporal algorithms to be used in conjunction with algorithms expecting a single time snapshot, thus simplifying software design and allowing adoption into existing pipeline frameworks. Our architecture also continues to work well in parallel distributed-memory environments. We demonstrate our architecture by modifying the popular VTK framework and exposing the functionality to the ParaView application. We use this framework to apply time-dependent algorithms on large data with a parallel cluster computer and thereby exercise a functionality that previously did not exist.

  10. Real-time massively parallel processing of spectral optical coherence tomography data on graphics processing units

    NASA Astrophysics Data System (ADS)

    Sylwestrzak, Marcin; Szlag, Daniel; Szkulmowski, Maciej; Targowski, Piotr

    2011-06-01

    In this contribution we describe a specialised data processing system for Spectral Optical Coherence Tomography (SOCT) biomedical imaging which utilises massively parallel data processing on a low-cost, Graphics Processing Unit (GPU). One of the most significant limitations of SOCT is the data processing time on the main processor of the computer (CPU), which is generally longer than the data acquisition. Therefore, real-time imaging with acceptable quality is limited to a small number of tomogram lines (A-scans). Recent progress in graphics cards technology gives a promising solution of this problem. The newest graphics processing units allow not only for a very high speed three dimensional (3D) rendering, but also for a general purpose parallel numerical calculations with efficiency higher than provided by the CPU. The presented system utilizes CUDATM graphic card and allows for a very effective real time SOCT imaging. The total imaging speed for 2D data consisting of 1200 A-scans is higher than refresh rate of a 120 Hz monitor. 3D rendering of the volume data build of 10 000 A-scans is performed with frame rate of about 9 frames per second. These frame rates include data transfer from a frame grabber to GPU, data processing and 3D rendering to the screen. The software description includes data flow, parallel processing and organization of threads. For illustration we show real time high resolution SOCT imaging of human skin and eye.

  11. Efficient Parallel Implementation of Active Appearance Model Fitting Algorithm on GPU

    PubMed Central

    Wang, Jinwei; Ma, Xirong; Zhu, Yuanping; Sun, Jizhou

    2014-01-01

    The active appearance model (AAM) is one of the most powerful model-based object detecting and tracking methods which has been widely used in various situations. However, the high-dimensional texture representation causes very time-consuming computations, which makes the AAM difficult to apply to real-time systems. The emergence of modern graphics processing units (GPUs) that feature a many-core, fine-grained parallel architecture provides new and promising solutions to overcome the computational challenge. In this paper, we propose an efficient parallel implementation of the AAM fitting algorithm on GPUs. Our design idea is fine grain parallelism in which we distribute the texture data of the AAM, in pixels, to thousands of parallel GPU threads for processing, which makes the algorithm fit better into the GPU architecture. We implement our algorithm using the compute unified device architecture (CUDA) on the Nvidia's GTX 650 GPU, which has the latest Kepler architecture. To compare the performance of our algorithm with different data sizes, we built sixteen face AAM models of different dimensional textures. The experiment results show that our parallel AAM fitting algorithm can achieve real-time performance for videos even on very high-dimensional textures. PMID:24723812

  12. Applying Parallel Processing Techniques to Tether Dynamics Simulation

    NASA Technical Reports Server (NTRS)

    Wells, B. Earl

    1996-01-01

    The focus of this research has been to determine the effectiveness of applying parallel processing techniques to a sizable real-world problem, the simulation of the dynamics associated with a tether which connects two objects in low earth orbit, and to explore the degree to which the parallelization process can be automated through the creation of new software tools. The goal has been to utilize this specific application problem as a base to develop more generally applicable techniques.

  13. Hybrid interconnection structures for real-time parallel processing

    NASA Technical Reports Server (NTRS)

    Kim, K. H.; Samson, John R., Jr.

    1989-01-01

    The use of hybrid interconnection structures that combine link connections and bus connections for real-time parallel processing is discussed. Idealistic parallel computation models for two real-time computing applications are described with attention given to a tightly coupled network model for object tracking and a network model for image processing. Consideration is given to the following different interconnection structures: the crossbar, the hypercube, the circular linked array, and the bus array.

  14. Parallel Processing of Large Scale Microphone Arrays for Sound Capture

    NASA Astrophysics Data System (ADS)

    Jan, Ea-Ee.

    1995-01-01

    Performance of microphone sound pick up is degraded by deleterious properties of the acoustic environment, such as multipath distortion (reverberation) and ambient noise. The degradation becomes more prominent in a teleconferencing environment in which the microphone is positioned far away from the speaker. Besides, the ideal teleconference should feel as easy and natural as face-to-face communication with another person. This suggests hands-free sound capture with no tether or encumbrance by hand-held or body-worn sound equipment. Microphone arrays for this application represent an appropriate approach. This research develops new microphone array and signal processing techniques for high quality hands-free sound capture in noisy, reverberant enclosures. The new techniques combine matched-filtering of individual sensors and parallel processing to provide acute spatial volume selectivity which is capable of mitigating the deleterious effects of noise interference and multipath distortion. The new method outperforms traditional delay-and-sum beamformers which provide only directional spatial selectivity. The research additionally explores truncated matched-filtering and random distribution of transducers to reduce complexity and improve sound capture quality. All designs are first established by computer simulation of array performance in reverberant enclosures. The simulation is achieved by a room model which can efficiently calculate the acoustic multipath in a rectangular enclosure up to a prescribed order of images. It also calculates the incident angle of the arriving signal. Experimental arrays were constructed and their performance was measured in real rooms. Real room data were collected in a hard-walled laboratory and a controllable variable acoustics enclosure of similar size, approximately 6 x 6 x 3 m. An extensive speech database was also collected in these two enclosures for future research on microphone arrays. The simulation results are shown to be

  15. Parallel processing of layout data with selective data distribution

    NASA Astrophysics Data System (ADS)

    Pereira, Mark; Bhat, Nitin; Srinivas, Preethi

    2006-10-01

    With the increase in layout data (GDSII) size due to finer geometries and resolution enhancement techniques such as Optical Proximity Correction (OPC) and Phase Shift Mask (PSM), layout data is proving to be too voluminous to process by single CPU machines. Post-layout tools have now moved towards distributed computing techniques to process this data more efficiently in terms of speed. Typical distributed computing architectures involve distributing the layout data to various workstations and then each workstation processing its part of the data in parallel. This approach will work well provided the amount of data that is to be distributed is not too large. As the size of the layout data is increasing significantly, the time taken to transfer the layout data between the workstations is turning out to be a major bottleneck. This bottleneck gets further highlighted because the time taken for actual operations gets almost linearly scaled down through employing higher number of workstations in the distributed computing environment and also because the clock speed of the workstations get continuously improved. The focus of this paper is on a smart way of distributing the layout data so that the amount of redundant data transfer is significantly reduced. This is achieved by selective data distribution wherein the layout data is fragmented and each workstation is provided with minimal and sufficient layout information for it to determine the actual fragments required for its processing.

  16. CRBLASTER: A Parallel-Processing Computational Framework for Embarrassingly Parallel Image-Analysis Algorithms

    NASA Astrophysics Data System (ADS)

    Mighell, Kenneth John

    2010-10-01

    The development of parallel-processing image-analysis codes is generally a challenging task that requires complicated choreography of interprocessor communications. If, however, the image-analysis algorithm is embarrassingly parallel, then the development of a parallel-processing implementation of that algorithm can be a much easier task to accomplish because, by definition, there is little need for communication between the compute processes. I describe the design, implementation, and performance of a parallel-processing image-analysis application, called crblaster, which does cosmic-ray rejection of CCD images using the embarrassingly parallel l.a.cosmic algorithm. crblaster is written in C using the high-performance computing industry standard Message Passing Interface (MPI) library. crblaster uses a two-dimensional image partitioning algorithm that partitions an input image into N rectangular subimages of nearly equal area; the subimages include sufficient additional pixels along common image partition edges such that the need for communication between computer processes is eliminated. The code has been designed to be used by research scientists who are familiar with C as a parallel-processing computational framework that enables the easy development of parallel-processing image-analysis programs based on embarrassingly parallel algorithms. The crblaster source code is freely available at the official application Web site at the National Optical Astronomy Observatory. Removing cosmic rays from a single 800 × 800 pixel Hubble Space Telescope WFPC2 image takes 44 s with the IRAF script lacos_im.cl running on a single core of an Apple Mac Pro computer with two 2.8 GHz quad-core Intel Xeon processors. crblaster is 7.4 times faster when processing the same image on a single core on the same machine. Processing the same image with crblaster simultaneously on all eight cores of the same machine takes 0.875 s—which is a speedup factor of 50.3 times faster than the

  17. Parallel Signal Processing and System Simulation using aCe

    NASA Technical Reports Server (NTRS)

    Dorband, John E.; Aburdene, Maurice F.

    2003-01-01

    Recently, networked and cluster computation have become very popular for both signal processing and system simulation. A new language is ideally suited for parallel signal processing applications and system simulation since it allows the programmer to explicitly express the computations that can be performed concurrently. In addition, the new C based parallel language (ace C) for architecture-adaptive programming allows programmers to implement algorithms and system simulation applications on parallel architectures by providing them with the assurance that future parallel architectures will be able to run their applications with a minimum of modification. In this paper, we will focus on some fundamental features of ace C and present a signal processing application (FFT).

  18. Solution-processed parallel tandem polymer solar cells using silver nanowires as intermediate electrode.

    PubMed

    Guo, Fei; Kubis, Peter; Li, Ning; Przybilla, Thomas; Matt, Gebhard; Stubhan, Tobias; Ameri, Tayebeh; Butz, Benjamin; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J

    2014-12-23

    Tandem architecture is the most relevant concept to overcome the efficiency limit of single-junction photovoltaic solar cells. Series-connected tandem polymer solar cells (PSCs) have advanced rapidly during the past decade. In contrast, the development of parallel-connected tandem cells is lagging far behind due to the big challenge in establishing an efficient interlayer with high transparency and high in-plane conductivity. Here, we report all-solution fabrication of parallel tandem PSCs using silver nanowires as intermediate charge collecting electrode. Through a rational interface design, a robust interlayer is established, enabling the efficient extraction and transport of electrons from subcells. The resulting parallel tandem cells exhibit high fill factors of ∼60% and enhanced current densities which are identical to the sum of the current densities of the subcells. These results suggest that solution-processed parallel tandem configuration provides an alternative avenue toward high performance photovoltaic devices. PMID:25405589

  19. High efficiency solar cell processing

    NASA Technical Reports Server (NTRS)

    Ho, F.; Iles, P. A.

    1985-01-01

    At the time of writing, cells made by several groups are approaching 19% efficiency. General aspects of the processing required for such cells are discussed. Most processing used for high efficiency cells is derived from space-cell or concentrator cell technology, and recent advances have been obtained from improved techniques rather than from better understanding of the limiting mechanisms. Theory and modeling are fairly well developed, and adequate to guide further asymptotic increases in performance of near conventional cells. There are several competitive cell designs with promise of higher performance ( 20%) but for these designs further improvements are required. The available cell processing technology to fabricate high efficiency cells is examined.

  20. Processing data communications events by awakening threads in parallel active messaging interface of a parallel computer

    DOEpatents

    Archer, Charles J.; Blocksome, Michael A.; Ratterman, Joseph D.; Smith, Brian E.

    2016-03-15

    Processing data communications events in a parallel active messaging interface (`PAMI`) of a parallel computer that includes compute nodes that execute a parallel application, with the PAMI including data communications endpoints, and the endpoints are coupled for data communications through the PAMI and through other data communications resources, including determining by an advance function that there are no actionable data communications events pending for its context, placing by the advance function its thread of execution into a wait state, waiting for a subsequent data communications event for the context; responsive to occurrence of a subsequent data communications event for the context, awakening by the thread from the wait state; and processing by the advance function the subsequent data communications event now pending for the context.

  1. Efficient graph algorithms for sequential and parallel computers. Doctoral thesis

    SciTech Connect

    Goldberg, A.V.

    1987-02-01

    This thesis studies graph algorithms, both in sequential and parallel contexts. In the outline of the thesis, algorithm complexities are stated in terms of the the number of vertices n, the number of edges m, the largest absolute value of capacities U, and the largest absolute value of costs C. Chapter 1 introduces a new approach to the maximum flow problem that leads to better algorithms for the problem. Chapter 2 is devoted to the minimum cost flow problem, which is a generalization of the maximum flow problem. Chapter 3 addresses implementation of parallel algorithms through a case study of an implementation of a parallel maximum flow algorithm. Parallel prefix operations play an important role in the implementation. Present experimental results achieved by the implementation are presented. Present parallel symmetry-breaking techniques are the main topic of Chapter 4.

  2. Parallel processing for pitch splitting decomposition

    NASA Astrophysics Data System (ADS)

    Barnes, Levi; Li, Yong; Wadkins, David; Biederman, Steve; Miloslavsky, Alex; Cork, Chris

    2009-10-01

    Decomposition of an input pattern in preparation for a double patterning process is an inherently global problem in which the influence of a local decomposition decision can be felt across an entire pattern. In spite of this, a large portion of the work can be massively distributed. Here, we discuss the advantages of geometric distribution for polygon operations with limited range of influence. Further, we have found that even the naturally global "coloring" step can, in large part, be handled in a geometrically local manner. In some practical cases, up to 70% of the work can be distributed geometrically. We also describe the methods for partitioning the problem into local pieces and present scaling data up to 100 CPUs. These techniques reduce DPT decomposition runtime by orders of magnitude.

  3. Parallel ALLSPD-3D: Speeding Up Combustor Analysis Via Parallel Processing

    NASA Technical Reports Server (NTRS)

    Fricker, David M.

    1997-01-01

    The ALLSPD-3D Computational Fluid Dynamics code for reacting flow simulation was run on a set of benchmark test cases to determine its parallel efficiency. These test cases included non-reacting and reacting flow simulations with varying numbers of processors. Also, the tests explored the effects of scaling the simulation with the number of processors in addition to distributing a constant size problem over an increasing number of processors. The test cases were run on a cluster of IBM RS/6000 Model 590 workstations with ethernet and ATM networking plus a shared memory SGI Power Challenge L workstation. The results indicate that the network capabilities significantly influence the parallel efficiency, i.e., a shared memory machine is fastest and ATM networking provides acceptable performance. The limitations of ethernet greatly hamper the rapid calculation of flows using ALLSPD-3D.

  4. Parallel algorithms for high-speed SAR processing

    NASA Astrophysics Data System (ADS)

    Mallorqui, Jordi J.; Bara, Marc; Broquetas, Antoni; Wis, Mariano; Martinez, Antonio; Nogueira, Leonardo; Moreno, Victoriano

    1998-11-01

    The mass production of SAR products and its usage on monitoring emergency situations (oil spill detection, floods, etc.) requires high-speed SAR processors. Two different parallel strategies for near real time SAR processing based on a multiblock version of the Chirp Scaling Algorithm (CSA) have been studied. The first one is useful for small companies that would like to reduce computation times with no extra investment. It uses a cluster of heterogeneous UNIX workstations as a parallel computer. The second one is oriented to institutions, which have to process large amounts of data in short times and can afford the cost of large parallel computers. The parallel programming has reduced in both cases the computational times when compared with the sequential versions.

  5. An efficient parallel algorithm for matrix-vector multiplication

    SciTech Connect

    Hendrickson, B.; Leland, R.; Plimpton, S.

    1993-03-01

    The multiplication of a vector by a matrix is the kernel computation of many algorithms in scientific computation. A fast parallel algorithm for this calculation is therefore necessary if one is to make full use of the new generation of parallel supercomputers. This paper presents a high performance, parallel matrix-vector multiplication algorithm that is particularly well suited to hypercube multiprocessors. For an n x n matrix on p processors, the communication cost of this algorithm is O(n/[radical]p + log(p)), independent of the matrix sparsity pattern. The performance of the algorithm is demonstrated by employing it as the kernel in the well-known NAS conjugate gradient benchmark, where a run time of 6.09 seconds was observed. This is the best published performance on this benchmark achieved to date using a massively parallel supercomputer.

  6. Efficient Helicopter Aerodynamic and Aeroacoustic Predictions on Parallel Computers

    NASA Technical Reports Server (NTRS)

    Wissink, Andrew M.; Lyrintzis, Anastasios S.; Strawn, Roger C.; Oliker, Leonid; Biswas, Rupak

    1996-01-01

    This paper presents parallel implementations of two codes used in a combined CFD/Kirchhoff methodology to predict the aerodynamics and aeroacoustics properties of helicopters. The rotorcraft Navier-Stokes code, TURNS, computes the aerodynamic flowfield near the helicopter blades and the Kirchhoff acoustics code computes the noise in the far field, using the TURNS solution as input. The overall parallel strategy adds MPI message passing calls to the existing serial codes to allow for communication between processors. As a result, the total code modifications required for parallel execution are relatively small. The biggest bottleneck in running the TURNS code in parallel comes from the LU-SGS algorithm that solves the implicit system of equations. We use a new hybrid domain decomposition implementation of LU-SGS to obtain good parallel performance on the SP-2. TURNS demonstrates excellent parallel speedups for quasi-steady and unsteady three-dimensional calculations of a helicopter blade in forward flight. The execution rate attained by the code on 114 processors is six times faster than the same cases run on one processor of the Cray C-90. The parallel Kirchhoff code also shows excellent parallel speedups and fast execution rates. As a performance demonstration, unsteady acoustic pressures are computed at 1886 far-field observer locations for a sample acoustics problem. The calculation requires over two hundred hours of CPU time on one C-90 processor but takes only a few hours on 80 processors of the SP2. The resultant far-field acoustic field is analyzed with state of-the-art audio and video rendering of the propagating acoustic signals.

  7. Parallel processing implementation for the coupled transport of photons and electrons using OpenMP

    NASA Astrophysics Data System (ADS)

    Doerner, Edgardo

    2016-05-01

    In this work the use of OpenMP to implement the parallel processing of the Monte Carlo (MC) simulation of the coupled transport for photons and electrons is presented. This implementation was carried out using a modified EGSnrc platform which enables the use of the Microsoft Visual Studio 2013 (VS2013) environment, together with the developing tools available in the Intel Parallel Studio XE 2015 (XE2015). The performance study of this new implementation was carried out in a desktop PC with a multi-core CPU, taking as a reference the performance of the original platform. The results were satisfactory, both in terms of scalability as parallelization efficiency.

  8. FPGA-Based Filterbank Implementation for Parallel Digital Signal Processing

    NASA Technical Reports Server (NTRS)

    Berner, Stephan; DeLeon, Phillip

    1999-01-01

    One approach to parallel digital signal processing decomposes a high bandwidth signal into multiple lower bandwidth (rate) signals by an analysis bank. After processing, the subband signals are recombined into a fullband output signal by a synthesis bank. This paper describes an implementation of the analysis and synthesis banks using (Field Programmable Gate Arrays) FPGAs.

  9. On Efficient Parallel Implementation of Moving Body Overset Grid Methods

    NASA Technical Reports Server (NTRS)

    Wissink, Andrew M.; Meakin, Robert L.; Warmbrodt, William (Technical Monitor)

    1997-01-01

    An investigation into the parallel performance of moving-body overset grid methods will be presented. Parallel versions of the OVERFLOW flow solver, DCF3D domain connectivity software, and SIXDO six-degree-of-freedom routine are coupled with an automatic load balance routine and tested for 3D Navier-Stokes calculations on the IBM SP2. The primary source of parallel inefficiency in moving and problems are the domain connectivity costs with DCF 3D. Although this algorithm constitutes a relatively low fraction of the total solution cost (e.g. 10-20%) in calculations on serial machines, the consequently cause a significant degradation in the overall parallel performance. The paper will highlight some approaches for improving the scalability of DCF3D. The paper will present results of a proposed new load balancing scheme that seeks more equal distribution of the inter-grid boundary points in order to more evenly load balance the donor search costs associated with DCF3D. Some preliminary results will also be given from a new solution-adaption algorithm coupled with OVERFLOW which incorporates overset cartesian grids with various levels of refinement. The measured parallel performance from a descending delta-wing configuration and a generic store-separation from a wing/pylon case will be presented.

  10. Mapping Pixel Windows To Vectors For Parallel Processing

    NASA Technical Reports Server (NTRS)

    Duong, Tuan A.

    1996-01-01

    Mapping performed by matrices of transistor switches. Arrays of transistor switches devised for use in forming simultaneous connections from square subarray (window) of n x n pixels within electronic imaging device containing np x np array of pixels to linear array of n(sup2) input terminals of electronic neural network or other parallel-processing circuit. Method helps to realize potential for rapidity in parallel processing for such applications as enhancement of images and recognition of patterns. In providing simultaneous connections, overcomes timing bottleneck or older multiplexing, serial-switching, and sample-and-hold methods.

  11. Active Storage Processing in a Parallel File System

    SciTech Connect

    Felix, Evan J.; Fox, Kevin M.; Regimbal, Kevin M.; Nieplocha, Jarek

    2006-01-01

    By creating a processing system within a parallel file system one can harness the power of unused processing power on servers that have very fast access to the disks they are serving. By inserting a module the Lustre file system the Active Storage Concept is able to perform processing with the file system architecture. Results of using this technology are presented as the results of the Supercomputing StorCloud Challenge Application are reviewed.

  12. Efficient parallel architecture for highly coupled real-time linear system applications

    NASA Technical Reports Server (NTRS)

    Carroll, Chester C.; Homaifar, Abdollah; Barua, Soumavo

    1988-01-01

    A systematic procedure is developed for exploiting the parallel constructs of computation in a highly coupled, linear system application. An overall top-down design approach is adopted. Differential equations governing the application under consideration are partitioned into subtasks on the basis of a data flow analysis. The interconnected task units constitute a task graph which has to be computed in every update interval. Multiprocessing concepts utilizing parallel integration algorithms are then applied for efficient task graph execution. A simple scheduling routine is developed to handle task allocation while in the multiprocessor mode. Results of simulation and scheduling are compared on the basis of standard performance indices. Processor timing diagrams are developed on the basis of program output accruing to an optimal set of processors. Basic architectural attributes for implementing the system are discussed together with suggestions for processing element design. Emphasis is placed on flexible architectures capable of accommodating widely varying application specifics.

  13. Efficient Parallel Learning of Hidden Markov Chain Models on SMPs

    NASA Astrophysics Data System (ADS)

    Li, Lei; Fu, Bin; Faloutsos, Christos

    Quad-core cpus have been a common desktop configuration for today's office. The increasing number of processors on a single chip opens new opportunity for parallel computing. Our goal is to make use of the multi-core as well as multi-processor architectures to speed up large-scale data mining algorithms. In this paper, we present a general parallel learning framework, Cut-And-Stitch, for training hidden Markov chain models. Particularly, we propose two model-specific variants, CAS-LDS for learning linear dynamical systems (LDS) and CAS-HMM for learning hidden Markov models (HMM). Our main contribution is a novel method to handle the data dependencies due to the chain structure of hidden variables, so as to parallelize the EM-based parameter learning algorithm. We implement CAS-LDS and CAS-HMM using OpenMP on two supercomputers and a quad-core commercial desktop. The experimental results show that parallel algorithms using Cut-And-Stitch achieve comparable accuracy and almost linear speedups over the traditional serial version.

  14. Parallel processing of atmospheric chemistry calculations: Preliminary considerations

    SciTech Connect

    Elliott, S.; Jones, P.

    1995-01-01

    Global climate calculations are already saturating the class modern vector supercomputers with only a few central processing units. Increased resolution and inclusion of routines to deal with biogeochemical portions of the terrestrial climate system will soon demand massively parallel approaches. The atmospheric photochemistry ensemble is intimately linked to climate through the trace greenhouse gases ozone and methane and modules for representing it are being attached to global three dimensional transport and GCM frameworks. Atmospheric kinetics involve dozens of highly interactive tracers and so will accentuate the need for parallel processing of earth system simulations. In the present text we lay some of the groundwork for addition of atmospheric kinetics packages to GCM and global scale atmospheric models on multiply parallel computers. The discussion is tailored for consumption by the photochemical modelling community. After a review of numerical atmospheric chemistry methods, we examine how kinetics can be implemented on a parallel computer. We concentrate especially on data layout and flexibility and how these can be implemented in various programming models. We conclude that chemistry can be implemented rather easily within existing frameworks of several parallel atmospheric models. However, memory limitations may preclude high resolution studies of global chemistry.

  15. Partitioning Rectangular and Structurally Nonsymmetric Sparse Matrices for Parallel Processing

    SciTech Connect

    B. Hendrickson; T.G. Kolda

    1998-09-01

    A common operation in scientific computing is the multiplication of a sparse, rectangular or structurally nonsymmetric matrix and a vector. In many applications the matrix- transpose-vector product is also required. This paper addresses the efficient parallelization of these operations. We show that the problem can be expressed in terms of partitioning bipartite graphs. We then introduce several algorithms for this partitioning problem and compare their performance on a set of test matrices.

  16. Recent development for the ITS code system: Parallel processing and visualization

    SciTech Connect

    Fan, W.C.; Turner, C.D.; Halbleib, J.A. Sr.; Kensek, R.P.

    1996-03-01

    A brief overview is given for two software developments related to the ITS code system. These developments provide parallel processing and visualization capabilities and thus allow users to perform ITS calculations more efficiently. Timing results and a graphical example are presented to demonstrate these capabilities.

  17. Real-Time Reconfigurable Interconnections for Parallel Optical Processing

    NASA Astrophysics Data System (ADS)

    McArdle, Neil; Taghizadeh, Mohammad R.

    1995-06-01

    In this letter we describe the advantages of a dynamic optical interconnection system for parallel information processing applications. The system is based on a liquid crystal television which acts as a binary phase-only spatial light modulator. We describe example algorithms where reconfigurable interconnects would be useful and present results of several interconnection topologies which have been implemented.

  18. Using Motivational Interviewing Techniques to Address Parallel Process in Supervision

    ERIC Educational Resources Information Center

    Giordano, Amanda; Clarke, Philip; Borders, L. DiAnne

    2013-01-01

    Supervision offers a distinct opportunity to experience the interconnection of counselor-client and counselor-supervisor interactions. One product of this network of interactions is parallel process, a phenomenon by which counselors unconsciously identify with their clients and subsequently present to their supervisors in a similar fashion…

  19. An Image Database on a Parallel Processing Network.

    ERIC Educational Resources Information Center

    Philip, G.; And Others

    1991-01-01

    Describes the design and development of an image database for photographs in the Ulster Museum (Northern Ireland) that used parallelism from a transputer network. Topics addressed include image processing techniques; documentation needed for the photographs, including indexing, classifying, and cataloging; problems; hardware and software aspects;…

  20. Parallel Processing of Objects in a Naming Task

    ERIC Educational Resources Information Center

    Meyer, Antje S.; Ouellet, Marc; Hacker, Christine

    2008-01-01

    The authors investigated whether speakers who named several objects processed them sequentially or in parallel. Speakers named object triplets, arranged in a triangle, in the order left, right, and bottom object. The left object was easy or difficult to identify and name. During the saccade from the left to the right object, the right object shown…

  1. Parallel Processing Method for Airborne Laser Scanning Data Using a PC Cluster and a Virtual Grid.

    PubMed

    Han, Soo Hee; Heo, Joon; Sohn, Hong Gyoo; Yu, Kiyun

    2009-01-01

    In this study, a parallel processing method using a PC cluster and a virtual grid is proposed for the fast processing of enormous amounts of airborne laser scanning (ALS) data. The method creates a raster digital surface model (DSM) by interpolating point data with inverse distance weighting (IDW), and produces a digital terrain model (DTM) by local minimum filtering of the DSM. To make a consistent comparison of performance between sequential and parallel processing approaches, the means of dealing with boundary data and of selecting interpolation centers were controlled for each processing node in parallel approach. To test the speedup, efficiency and linearity of the proposed algorithm, actual ALS data up to 134 million points were processed with a PC cluster consisting of one master node and eight slave nodes. The results showed that parallel processing provides better performance when the computational overhead, the number of processors, and the data size become large. It was verified that the proposed algorithm is a linear time operation and that the products obtained by parallel processing are identical to those produced by sequential processing. PMID:22574032

  2. Idaho Chemical Processing Plant Process Efficiency improvements

    SciTech Connect

    Griebenow, B.

    1996-03-01

    In response to decreasing funding levels available to support activities at the Idaho Chemical Processing Plant (ICPP) and a desire to be cost competitive, the Department of Energy Idaho Operations Office (DOE-ID) and Lockheed Idaho Technologies Company have increased their emphasis on cost-saving measures. The ICPP Effectiveness Improvement Initiative involves many activities to improve cost effectiveness and competitiveness. This report documents the methodology and results of one of those cost cutting measures, the Process Efficiency Improvement Activity. The Process Efficiency Improvement Activity performed a systematic review of major work processes at the ICPP to increase productivity and to identify nonvalue-added requirements. A two-phase approach was selected for the activity to allow for near-term implementation of relatively easy process modifications in the first phase while obtaining long-term continuous improvement in the second phase and beyond. Phase I of the initiative included a concentrated review of processes that had a high potential for cost savings with the intent of realizing savings in Fiscal Year 1996 (FY-96.) Phase II consists of implementing long-term strategies too complex for Phase I implementation and evaluation of processes not targeted for Phase I review. The Phase II effort is targeted for realizing cost savings in FY-97 and beyond.

  3. An efficient parallel algorithm for three-dimensional analysis of subsidence above gas reservoirs

    NASA Astrophysics Data System (ADS)

    Schrefler, B. A.; Wang, X.; Salomoni, V. A.; Zuccolo, G.

    1999-09-01

    In this paper an efficient parallel algorithm to solve a three-dimensional problem of subsidence above exploited gas reservoirs is presented. The parallel program is developed on a cluster of workstations. The parallel virtual machine (PVM) system is used to handle communications among networked workstations. The method has advantages such as numbering of the finite element mesh in an arbitrary manner, simple programming organization, smaller core requirements and computation times. An implementation of this parallel method on workstations is discussed, the speed-up and efficiency of this method being demonstrated by a numerical example. Copyright

  4. On the Optimality of Serial and Parallel Processing in the Psychological Refractory Period Paradigm: Effects of the Distribution of Stimulus Onset Asynchronies

    ERIC Educational Resources Information Center

    Miller, Jeff; Ulrich, Rolf; Rolke, Bettina

    2009-01-01

    Within the context of the psychological refractory period (PRP) paradigm, we developed a general theoretical framework for deciding when it is more efficient to process two tasks in serial and when it is more efficient to process them in parallel. This analysis suggests that a serial mode is more efficient than a parallel mode under a wide variety…

  5. Automating the parallel processing of fluid and structural dynamics calculations

    NASA Technical Reports Server (NTRS)

    Arpasi, Dale J.; Cole, Gary L.

    1987-01-01

    The NASA Lewis Research Center is actively involved in the development of expert system technology to assist users in applying parallel processing to computational fluid and structural dynamic analysis. The goal of this effort is to eliminate the necessity for the physical scientist to become a computer scientist in order to effectively use the computer as a research tool. Programming and operating software utilities have previously been developed to solve systems of ordinary nonlinear differential equations on parallel scalar processors. Current efforts are aimed at extending these capabilties to systems of partial differential equations, that describe the complex behavior of fluids and structures within aerospace propulsion systems. This paper presents some important considerations in the redesign, in particular, the need for algorithms and software utilities that can automatically identify data flow patterns in the application program and partition and allocate calculations to the parallel processors. A library-oriented multiprocessing concept for integrating the hardware and software functions is described.

  6. Automating the parallel processing of fluid and structural dynamics calculations

    NASA Technical Reports Server (NTRS)

    Arpasi, Dale J.; Cole, Gary L.

    1987-01-01

    The NASA Lewis Research Center is actively involved in the development of expert system technology to assist users in applying parallel processing to computational fluid and structural dynamic analysis. The goal of this effort is to eliminate the necessity for the physical scientist to become a computer scientist in order to effectively use the computer as a research tool. Programming and operating software utilities have previously been developed to solve systems of ordinary nonlinear differential equations on parallel scalar processors. Current efforts are aimed at extending these capabilities to systems of partial differential equations, that describe the complex behavior of fluids and structures within aerospace propulsion systems. This paper presents some important considerations in the redesign, in particular, the need for algorithms and software utilities that can automatically identify data flow patterns in the application program and partition and allocate calculations to the parallel processors. A library-oriented multiprocessing concept for integrating the hardware and software functions is described.

  7. The remote sensing image segmentation mean shift algorithm parallel processing based on MapReduce

    NASA Astrophysics Data System (ADS)

    Chen, Xi; Zhou, Liqing

    2015-12-01

    With the development of satellite remote sensing technology and the remote sensing image data, traditional remote sensing image segmentation technology cannot meet the massive remote sensing image processing and storage requirements. This article put cloud computing and parallel computing technology in remote sensing image segmentation process, and build a cheap and efficient computer cluster system that uses parallel processing to achieve MeanShift algorithm of remote sensing image segmentation based on the MapReduce model, not only to ensure the quality of remote sensing image segmentation, improved split speed, and better meet the real-time requirements. The remote sensing image segmentation MeanShift algorithm parallel processing algorithm based on MapReduce shows certain significance and a realization of value.

  8. Cloud parallel processing of tandem mass spectrometry based proteomics data.

    PubMed

    Mohammed, Yassene; Mostovenko, Ekaterina; Henneman, Alex A; Marissen, Rob J; Deelder, André M; Palmblad, Magnus

    2012-10-01

    Data analysis in mass spectrometry based proteomics struggles to keep pace with the advances in instrumentation and the increasing rate of data acquisition. Analyzing this data involves multiple steps requiring diverse software, using different algorithms and data formats. Speed and performance of the mass spectral search engines are continuously improving, although not necessarily as needed to face the challenges of acquired big data. Improving and parallelizing the search algorithms is one possibility; data decomposition presents another, simpler strategy for introducing parallelism. We describe a general method for parallelizing identification of tandem mass spectra using data decomposition that keeps the search engine intact and wraps the parallelization around it. We introduce two algorithms for decomposing mzXML files and recomposing resulting pepXML files. This makes the approach applicable to different search engines, including those relying on sequence databases and those searching spectral libraries. We use cloud computing to deliver the computational power and scientific workflow engines to interface and automate the different processing steps. We show how to leverage these technologies to achieve faster data analysis in proteomics and present three scientific workflows for parallel database as well as spectral library search using our data decomposition programs, X!Tandem and SpectraST.

  9. Parallelizing the Cellular Potts Model on graphics processing units

    NASA Astrophysics Data System (ADS)

    Tapia, José Juan; D'Souza, Roshan M.

    2011-04-01

    The Cellular Potts Model (CPM) is a lattice based modeling technique used for simulating cellular structures in computational biology. The computational complexity of the model means that current serial implementations restrict the size of simulation to a level well below biological relevance. Parallelization on computing clusters enables scaling the size of the simulation but marginally addresses computational speed due to the limited memory bandwidth between nodes. In this paper we present new data-parallel algorithms and data structures for simulating the Cellular Potts Model on graphics processing units. Our implementations handle most terms in the Hamiltonian, including cell-cell adhesion constraint, cell volume constraint, cell surface area constraint, and cell haptotaxis. We use fine level checkerboards with lock mechanisms using atomic operations to enable consistent updates while maintaining a high level of parallelism. A new data-parallel memory allocation algorithm has been developed to handle cell division. Tests show that our implementation enables simulations of >10 cells with lattice sizes of up to 256 3 on a single graphics card. Benchmarks show that our implementation runs ˜80× faster than serial implementations, and ˜5× faster than previous parallel implementations on computing clusters consisting of 25 nodes. The wide availability and economy of graphics cards mean that our techniques will enable simulation of realistically sized models at a fraction of the time and cost of previous implementations and are expected to greatly broaden the scope of CPM applications.

  10. Parallel-Processing Software for Correlating Stereo Images

    NASA Technical Reports Server (NTRS)

    Klimeck, Gerhard; Deen, Robert; Mcauley, Michael; DeJong, Eric

    2007-01-01

    A computer program implements parallel- processing algorithms for cor relating images of terrain acquired by stereoscopic pairs of digital stereo cameras on an exploratory robotic vehicle (e.g., a Mars rove r). Such correlations are used to create three-dimensional computatio nal models of the terrain for navigation. In this program, the scene viewed by the cameras is segmented into subimages. Each subimage is assigned to one of a number of central processing units (CPUs) opera ting simultaneously.

  11. Parallel Processing of Broad-Band PPM Signals

    NASA Technical Reports Server (NTRS)

    Gray, Andrew; Kang, Edward; Lay, Norman; Vilnrotter, Victor; Srinivasan, Meera; Lee, Clement

    2010-01-01

    A parallel-processing algorithm and a hardware architecture to implement the algorithm have been devised for timeslot synchronization in the reception of pulse-position-modulated (PPM) optical or radio signals. As in the cases of some prior algorithms and architectures for parallel, discrete-time, digital processing of signals other than PPM, an incoming broadband signal is divided into multiple parallel narrower-band signals by means of sub-sampling and filtering. The number of parallel streams is chosen so that the frequency content of the narrower-band signals is low enough to enable processing by relatively-low speed complementary metal oxide semiconductor (CMOS) electronic circuitry. The algorithm and architecture are intended to satisfy requirements for time-varying time-slot synchronization and post-detection filtering, with correction of timing errors independent of estimation of timing errors. They are also intended to afford flexibility for dynamic reconfiguration and upgrading. The architecture is implemented in a reconfigurable CMOS processor in the form of a field-programmable gate array. The algorithm and its hardware implementation incorporate three separate time-varying filter banks for three distinct functions: correction of sub-sample timing errors, post-detection filtering, and post-detection estimation of timing errors. The design of the filter bank for correction of timing errors, the method of estimating timing errors, and the design of a feedback-loop filter are governed by a host of parameters, the most critical one, with regard to processing very broadband signals with CMOS hardware, being the number of parallel streams (equivalently, the rate-reduction parameter).

  12. Highly scalable parallel processing of extracellular recordings of Multielectrode Arrays.

    PubMed

    Gehring, Tiago V; Vasilaki, Eleni; Giugliano, Michele

    2015-01-01

    Technological advances of Multielectrode Arrays (MEAs) used for multisite, parallel electrophysiological recordings, lead to an ever increasing amount of raw data being generated. Arrays with hundreds up to a few thousands of electrodes are slowly seeing widespread use and the expectation is that more sophisticated arrays will become available in the near future. In order to process the large data volumes resulting from MEA recordings there is a pressing need for new software tools able to process many data channels in parallel. Here we present a new tool for processing MEA data recordings that makes use of new programming paradigms and recent technology developments to unleash the power of modern highly parallel hardware, such as multi-core CPUs with vector instruction sets or GPGPUs. Our tool builds on and complements existing MEA data analysis packages. It shows high scalability and can be used to speed up some performance critical pre-processing steps such as data filtering and spike detection, helping to make the analysis of larger data sets tractable. PMID:26737215

  13. Highly scalable parallel processing of extracellular recordings of Multielectrode Arrays.

    PubMed

    Gehring, Tiago V; Vasilaki, Eleni; Giugliano, Michele

    2015-01-01

    Technological advances of Multielectrode Arrays (MEAs) used for multisite, parallel electrophysiological recordings, lead to an ever increasing amount of raw data being generated. Arrays with hundreds up to a few thousands of electrodes are slowly seeing widespread use and the expectation is that more sophisticated arrays will become available in the near future. In order to process the large data volumes resulting from MEA recordings there is a pressing need for new software tools able to process many data channels in parallel. Here we present a new tool for processing MEA data recordings that makes use of new programming paradigms and recent technology developments to unleash the power of modern highly parallel hardware, such as multi-core CPUs with vector instruction sets or GPGPUs. Our tool builds on and complements existing MEA data analysis packages. It shows high scalability and can be used to speed up some performance critical pre-processing steps such as data filtering and spike detection, helping to make the analysis of larger data sets tractable.

  14. Efficient separations & processing crosscutting program

    SciTech Connect

    1996-08-01

    The Efficient Separations and Processing Crosscutting Program (ESP) was created in 1991 to identify, develop, and perfect chemical and physical separations technologies and chemical processes which treat wastes and address environmental problems throughout the DOE complex. The ESP funds several multiyear tasks that address high-priority waste remediation problems involving high-level, low-level, transuranic, hazardous, and mixed (radioactive and hazardous) wastes. The ESP supports applied research and development (R & D) leading to the demonstration or use of these separations technologies by other organizations within the Department of Energy (DOE), Office of Environmental Management.

  15. Parallel System Architecture (PSA): An efficient approach for automatic recognition of volcano-seismic events

    NASA Astrophysics Data System (ADS)

    Cortés, Guillermo; García, Luz; Álvarez, Isaac; Benítez, Carmen; de la Torre, Ángel; Ibáñez, Jesús

    2014-02-01

    Automatic recognition of volcano-seismic events is becoming one of the most demanded features in the early warning area at continuous monitoring facilities. While human-driven cataloguing is time-consuming and often an unreliable task, an appropriate machine framework allows expert technicians to focus only on result analysis and decision-making. This work presents an alternative to serial architectures used in classic recognition systems introducing a parallel implementation of the whole process: configuration, feature extraction, feature selection and classification stages are independently carried out for each type of events in order to exploit the intrinsic properties of each signal class. The system uses Gaussian Mixture Models (GMMs) to classify the database recorded at Deception Volcano Island (Antarctica) obtaining a baseline recognition rate of 84% with a cepstral-based waveform parameterization in the serial architecture. The parallel approach increases the results to close to 92% using mixture-based parameterization vectors or up to 91% when the vector size is reduced by 19% via the Discriminative Feature Selection (DFS) algorithm. Besides the result improvement, the parallel architecture represents a major step in terms of flexibility and reliability thanks to the class-focused analysis, providing an efficient tool for monitoring observatories which require real-time solutions.

  16. Semi-automatic process partitioning for parallel computation

    NASA Technical Reports Server (NTRS)

    Koelbel, Charles; Mehrotra, Piyush; Vanrosendale, John

    1988-01-01

    On current multiprocessor architectures one must carefully distribute data in memory in order to achieve high performance. Process partitioning is the operation of rewriting an algorithm as a collection of tasks, each operating primarily on its own portion of the data, to carry out the computation in parallel. A semi-automatic approach to process partitioning is considered in which the compiler, guided by advice from the user, automatically transforms programs into such an interacting task system. This approach is illustrated with a picture processing example written in BLAZE, which is transformed into a task system maximizing locality of memory reference.

  17. A dataflow analysis tool for parallel processing of algorithms

    NASA Technical Reports Server (NTRS)

    Jones, Robert L., III

    1993-01-01

    A graph-theoretic design process and software tool is presented for selecting a multiprocessing scheduling solution for a class of computational problems. The problems of interest are those that can be described using a dataflow graph and are intended to be executed repetitively on a set of identical parallel processors. Typical applications include signal processing and control law problems. Graph analysis techniques are introduced and shown to effectively determine performance bounds, scheduling constraints, and resource requirements. The software tool is shown to facilitate the application of the design process to a given problem.

  18. Digital intermediate frequency QAM modulator using parallel processing

    DOEpatents

    Pao, Hsueh-Yuan; Tran, Binh-Nien

    2008-05-27

    The digital Intermediate Frequency (IF) modulator applies to various modulation types and offers a simple and low cost method to implement a high-speed digital IF modulator using field programmable gate arrays (FPGAs). The architecture eliminates multipliers and sequential processing by storing the pre-computed modulated cosine and sine carriers in ROM look-up-tables (LUTs). The high-speed input data stream is parallel processed using the corresponding LUTs, which reduces the main processing speed, allowing the use of low cost FPGAs.

  19. An Efficient Objective Analysis System for Parallel Computers

    NASA Technical Reports Server (NTRS)

    Stobie, J.

    1999-01-01

    A new atmospheric objective analysis system designed for parallel computers will be described. The system can produce a global analysis (on a 1 X 1 lat-lon grid with 18 levels of heights and winds and 10 levels of moisture) using 120,000 observations in 17 minutes on 32 CPUs (SGI Origin 2000). No special parallel code is needed (e.g. MPI or multitasking) and the 32 CPUs do not have to be on the same platform. The system is totally portable and can run on several different architectures at once. In addition, the system can easily scale up to 100 or more CPUS. This will allow for much higher resolution and significant increases in input data. The system scales linearly as the number of observations and the number of grid points. The cost overhead in going from 1 to 32 CPUs is 18%. In addition, the analysis results are identical regardless of the number of processors used. This system has all the characteristics of optimal interpolation, combining detailed instrument and first guess error statistics to produce the best estimate of the atmospheric state. Static tests with a 2 X 2.5 resolution version of this system showed it's analysis increments are comparable to the latest NASA operational system including maintenance of mass-wind balance. Results from several months of cycling test in the Goddard EOS Data Assimilation System (GEOS DAS) show this new analysis retains the same level of agreement between the first guess and observations (O-F statistics) as the current operational system.

  20. An Efficient Objective Analysis System for Parallel Computers

    NASA Technical Reports Server (NTRS)

    Stobie, James G.

    1999-01-01

    A new objective analysis system designed for parallel computers will be described. The system can produce a global analysis (on a 2 x 2.5 lat-lon grid with 20 levels of heights and winds and 10 levels of moisture) using 120,000 observations in less than 3 minutes on 32 CPUs (SGI Origin 2000). No special parallel code is needed (e.g. MPI or multitasking) and the 32 CPUs do not have to be on the same platform. The system Ls totally portable and can run on -several different architectures at once. In addition, the system can easily scale up to 100 or more CPUS. This will allow for much higher resolution and significant increases in input data. The system scales linearly as the number of observations and the number of grid points. The cost overhead in going from I to 32 CPus is 18%. in addition, the analysis results are identical regardless of the number of processors used. T'his system has all the characteristics of optimal interpolation, combining detailed instrument and first guess error statistics to produce the best estimate of the atmospheric state. It also includes a new quality control (buddy check) system. Static tests with the system showed it's analysis increments are comparable to the latest NASA operational system including maintenance of mass-wind balance. Results from a 2-month cycling test in the Goddard EOS Data Assimilation System (GEOS DAS) show this new analysis retains the same level of agreement between the first guess and observations (0-F statistics) throughout the entire two months.

  1. Transactional memories: A new abstraction for parallel processing

    SciTech Connect

    Fasel, J.H.; Lubeck, O.M.; Agrawal, D.; Bruno, J.L.; El Abbadi, A.

    1997-12-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Current distributed memory multiprocessor computer systems make the development of parallel programs difficult. From a programmer`s perspective, it would be most desirable if the underlying hardware and software could provide the programming abstraction commonly referred to as sequential consistency--a single address space and multiple threads; but enforcement of sequential consistency limits opportunities for architectural and operating system performance optimizations, leading to poor performance. Recently, Herlihy and Moss have introduced a new abstraction called transactional memories for parallel programming. The programming model is shared memory with multiple threads. However, data consistency is obtained through the use of transactions rather than mutual exclusion based on locking. The transaction approach permits the underlying system to exploit the potential parallelism in transaction processing. The authors explore the feasibility of designing parallel programs using the transaction paradigm for data consistency and a barrier type of thread synchronization.

  2. Parallel Visualization Co-Processing of Overnight CFD Propulsion Applications

    NASA Technical Reports Server (NTRS)

    Edwards, David E.; Haimes, Robert

    1999-01-01

    An interactive visualization system pV3 is being developed for the investigation of advanced computational methodologies employing visualization and parallel processing for the extraction of information contained in large-scale transient engineering simulations. Visual techniques for extracting information from the data in terms of cutting planes, iso-surfaces, particle tracing and vector fields are included in this system. This paper discusses improvements to the pV3 system developed under NASA's Affordable High Performance Computing project.

  3. External sorting: I/O analysis and parallel processing techniques

    SciTech Connect

    Kwan, S.C.

    1986-01-01

    This thesis deals with sorting of data that are much too large to fit in main memory or external sorting. The author focuses on two aspects of external sorting: I/O analysis and parallel processing techniques. Storage device models are defined and applied to analyze the I/O complexities of multi-way merge sort and tag sort (or key sort). It is shown that using higher-merge order, through, reduces the number of merge passes, causes excessive random I/O accesses and degrades the overall I/O performance of multi-way merge sort. Techniques are developed for producing long runs in merge sort and for rearranging the records in tag sort after their ranks are determined. A lower bound for the I/O access time or rearranging the records in tag sort is derived. Two methods are explored for implementing distribution sort on parallel computers. The first method, multi-pass distribution sort, determines the bucket ranges with one read pass over the input file, and uses subsequent passes to distribute the data into buckets and sort them. The distribution and sorting of the buckets are processed in parallel using a two-stage pipeline. The second method, one-pass distribution sort, coalesces the bucket partition, bucket distribution, and sort-bucket phases all together so that the input file needs to be processed only once.

  4. The study of multi-granularity switching based on parallel processing routing technology

    NASA Astrophysics Data System (ADS)

    Wang, Yubao; Hao, Xiaoran; Bai, Jian; Hu, Haochen

    A novel parallel processing optical code label-switched paths (PP-OC-LSPs) is proposed to achieve efficient conversion performance for core router and large throughput in optical network, which combines the merits of optical label switching (OLS), optical code-generalized multi-protocol label switching (OC-GMPLS), and optical code division multiplexing-paths (OCDM-paths) technology. In the proposed technology, the smallest switching granularity is an optical code which carries the label information of data packets and would be parallel converted in the core router. In the edge node, the label and payload are separated by using the optical polarity characteristics, and encoded/decoded with two different code series based on OCDM techniques so as to process them in parallel. Compared with the OLS, its switching capability has been extended to support fiber switching, wavelength switching, and OCDM switching. We present simulation results to demonstrate its performance over OCDM-paths technology.

  5. Computation of the Density Matrix in Electronic Structure Theory in Parallel on Multiple Graphics Processing Units.

    PubMed

    Cawkwell, M J; Wood, M A; Niklasson, Anders M N; Mniszewski, S M

    2014-12-01

    The algorithm developed in Cawkwell, M. J. et al. J. Chem. Theory Comput. 2012 , 8 , 4094 for the computation of the density matrix in electronic structure theory on a graphics processing unit (GPU) using the second-order spectral projection (SP2) method [ Niklasson, A. M. N. Phys. Rev. B 2002 , 66 , 155115 ] has been efficiently parallelized over multiple GPUs on a single compute node. The parallel implementation provides significant speed-ups with respect to the single GPU version with no loss of accuracy. The performance and accuracy of the parallel GPU-based algorithm is compared with the performance of the SP2 algorithm and traditional matrix diagonalization methods on a multicore central processing unit (CPU).

  6. An efficient parallel implementation of explicit multirate Runge–Kutta schemes for discontinuous Galerkin computations

    SciTech Connect

    Seny, Bruno Lambrechts, Jonathan; Toulorge, Thomas; Legat, Vincent; Remacle, Jean-François

    2014-01-01

    Although explicit time integration schemes require small computational efforts per time step, their efficiency is severely restricted by their stability limits. Indeed, the multi-scale nature of some physical processes combined with highly unstructured meshes can lead some elements to impose a severely small stable time step for a global problem. Multirate methods offer a way to increase the global efficiency by gathering grid cells in appropriate groups under local stability conditions. These methods are well suited to the discontinuous Galerkin framework. The parallelization of the multirate strategy is challenging because grid cells have different workloads. The computational cost is different for each sub-time step depending on the elements involved and a classical partitioning strategy is not adequate any more. In this paper, we propose a solution that makes use of multi-constraint mesh partitioning. It tends to minimize the inter-processor communications, while ensuring that the workload is almost equally shared by every computer core at every stage of the algorithm. Particular attention is given to the simplicity of the parallel multirate algorithm while minimizing computational and communication overheads. Our implementation makes use of the MeTiS library for mesh partitioning and the Message Passing Interface for inter-processor communication. Performance analyses for two and three-dimensional practical applications confirm that multirate methods preserve important computational advantages of explicit methods up to a significant number of processors.

  7. An efficient parallel implementation of explicit multirate Runge-Kutta schemes for discontinuous Galerkin computations

    NASA Astrophysics Data System (ADS)

    Seny, Bruno; Lambrechts, Jonathan; Toulorge, Thomas; Legat, Vincent; Remacle, Jean-François

    2014-01-01

    Although explicit time integration schemes require small computational efforts per time step, their efficiency is severely restricted by their stability limits. Indeed, the multi-scale nature of some physical processes combined with highly unstructured meshes can lead some elements to impose a severely small stable time step for a global problem. Multirate methods offer a way to increase the global efficiency by gathering grid cells in appropriate groups under local stability conditions. These methods are well suited to the discontinuous Galerkin framework. The parallelization of the multirate strategy is challenging because grid cells have different workloads. The computational cost is different for each sub-time step depending on the elements involved and a classical partitioning strategy is not adequate any more. In this paper, we propose a solution that makes use of multi-constraint mesh partitioning. It tends to minimize the inter-processor communications, while ensuring that the workload is almost equally shared by every computer core at every stage of the algorithm. Particular attention is given to the simplicity of the parallel multirate algorithm while minimizing computational and communication overheads. Our implementation makes use of the MeTiS library for mesh partitioning and the Message Passing Interface for inter-processor communication. Performance analyses for two and three-dimensional practical applications confirm that multirate methods preserve important computational advantages of explicit methods up to a significant number of processors.

  8. Efficient Out of Core Sorting Algorithms for the Parallel Disks Model.

    PubMed

    Kundeti, Vamsi; Rajasekaran, Sanguthevar

    2011-11-01

    In this paper we present efficient algorithms for sorting on the Parallel Disks Model (PDM). Numerous asymptotically optimal algorithms have been proposed in the literature. However many of these merge based algorithms have large underlying constants in the time bounds, because they suffer from the lack of read parallelism on PDM. The irregular consumption of the runs during the merge affects the read parallelism and contributes to the increased sorting time. In this paper we first introduce a novel idea called the dirty sequence accumulation that improves the read parallelism. Secondly, we show analytically that this idea can reduce the number of parallel I/O's required to sort the input close to the lower bound of [Formula: see text]. We experimentally verify our dirty sequence idea with the standard R-Way merge and show that our idea can reduce the number of parallel I/Os to sort on PDM significantly.

  9. Parallel-Processing Equalizers for Multi-Gbps Communications

    NASA Technical Reports Server (NTRS)

    Gray, Andrew; Ghuman, Parminder; Hoy, Scott; Satorius, Edgar H.

    2004-01-01

    Architectures have been proposed for the design of frequency-domain least-mean-square complex equalizers that would be integral parts of parallel- processing digital receivers of multi-gigahertz radio signals and other quadrature-phase-shift-keying (QPSK) or 16-quadrature-amplitude-modulation (16-QAM) of data signals at rates of multiple gigabits per second. Equalizers as used here denotes receiver subsystems that compensate for distortions in the phase and frequency responses of the broad-band radio-frequency channels typically used to convey such signals. The proposed architectures are suitable for realization in very-large-scale integrated (VLSI) circuitry and, in particular, complementary metal oxide semiconductor (CMOS) application- specific integrated circuits (ASICs) operating at frequencies lower than modulation symbol rates. A digital receiver of the type to which the proposed architecture applies (see Figure 1) would include an analog-to-digital converter (A/D) operating at a rate, fs, of 4 samples per symbol period. To obtain the high speed necessary for sampling, the A/D and a 1:16 demultiplexer immediately following it would be constructed as GaAs integrated circuits. The parallel-processing circuitry downstream of the demultiplexer, including a demodulator followed by an equalizer, would operate at a rate of only fs/16 (in other words, at 1/4 of the symbol rate). The output from the equalizer would be four parallel streams of in-phase (I) and quadrature (Q) samples.

  10. Regional-scale calculation of the LS factor using parallel processing

    NASA Astrophysics Data System (ADS)

    Liu, Kai; Tang, Guoan; Jiang, Ling; Zhu, A.-Xing; Yang, Jianyi; Song, Xiaodong

    2015-05-01

    With the increase of data resolution and the increasing application of USLE over large areas, the existing serial implementation of algorithms for computing the LS factor is becoming a bottleneck. In this paper, a parallel processing model based on message passing interface (MPI) is presented for the calculation of the LS factor, so that massive datasets at a regional scale can be processed efficiently. The parallel model contains algorithms for calculating flow direction, flow accumulation, drainage network, slope, slope length and the LS factor. According to the existence of data dependence, the algorithms are divided into local algorithms and global algorithms. Parallel strategy are designed according to the algorithm characters including the decomposition method for maintaining the integrity of the results, optimized workflow for reducing the time taken for exporting the unnecessary intermediate data and a buffer-communication-computation strategy for improving the communication efficiency. Experiments on a multi-node system show that the proposed parallel model allows efficient calculation of the LS factor at a regional scale with a massive dataset.

  11. Probabilistic structural mechanics research for parallel processing computers

    NASA Technical Reports Server (NTRS)

    Sues, Robert H.; Chen, Heh-Chyun; Twisdale, Lawrence A.; Martin, William R.

    1991-01-01

    Aerospace structures and spacecraft are a complex assemblage of structural components that are subjected to a variety of complex, cyclic, and transient loading conditions. Significant modeling uncertainties are present in these structures, in addition to the inherent randomness of material properties and loads. To properly account for these uncertainties in evaluating and assessing the reliability of these components and structures, probabilistic structural mechanics (PSM) procedures must be used. Much research has focused on basic theory development and the development of approximate analytic solution methods in random vibrations and structural reliability. Practical application of PSM methods was hampered by their computationally intense nature. Solution of PSM problems requires repeated analyses of structures that are often large, and exhibit nonlinear and/or dynamic response behavior. These methods are all inherently parallel and ideally suited to implementation on parallel processing computers. New hardware architectures and innovative control software and solution methodologies are needed to make solution of large scale PSM problems practical.

  12. Reducing neural network training time with parallel processing

    NASA Technical Reports Server (NTRS)

    Rogers, James L., Jr.; Lamarsh, William J., II

    1995-01-01

    Obtaining optimal solutions for engineering design problems is often expensive because the process typically requires numerous iterations involving analysis and optimization programs. Previous research has shown that a near optimum solution can be obtained in less time by simulating a slow, expensive analysis with a fast, inexpensive neural network. A new approach has been developed to further reduce this time. This approach decomposes a large neural network into many smaller neural networks that can be trained in parallel. Guidelines are developed to avoid some of the pitfalls when training smaller neural networks in parallel. These guidelines allow the engineer: to determine the number of nodes on the hidden layer of the smaller neural networks; to choose the initial training weights; and to select a network configuration that will capture the interactions among the smaller neural networks. This paper presents results describing how these guidelines are developed.

  13. Abstract machine based execution model for computer architecture design and efficient implementation of logic programs in parallel

    SciTech Connect

    Hermenegildo, M.V.

    1986-01-01

    The term Logic Programming refers to a variety of computer languages and execution models based on the traditional concept of Symbolic Logic. The expressive power of these languages offers promise to be of great assistance in facing the programming challenges of present and future symbolic processing applications in artificial intelligence, knowledge-based systems, and many other areas of computing. This dissertation presents an efficient parallel execution model for logic programs. The model is described from the source language level down to an Abstract Machine level, suitable for direct implementation on existing parallel systems or for the design of special purpose parallel architectures. Few assumptions are made at the source language level and, therefore, the techniques developed and the general Abstract Machine design are applicable to a variety of logic (and also functional) languages. These techniques offer efficient solutions to several areas of parallel Logic Programming implementation previously considered problematic or a source of considerable overhead, such as the detection and handling of variable binding conflicts in AND-parallelism, the specification of control and management of the execution tree, the treatment of distributed backtracking, and goal scheduling and memory management issues, etc. A parallel Abstract Machine design is offered, specifying data areas, operation, and a suitable instruction set.

  14. Efficient data IO for a Parallel Global Cloud Resolving Model

    SciTech Connect

    Palmer, Bruce J.; Koontz, Annette S.; Schuchardt, Karen L.; Heikes, Ross P.; Randall, David A.

    2011-11-26

    Execution of a Global Cloud Resolving Model (GCRM) at target resolutions of 2-4 km will generate, at a minimum, 10s of Gigabytes of data per variable per snapshot. Writing this data to disk without creating a serious bottleneck in the execution of the GCRM code while also supporting efficient post-execution data analysis is a significant challenge. This paper discusses an Input/Output (IO) application programmer interface (API) for the GCRM that efficiently moves data from the model to disk while maintaining support for community standard formats, avoiding the creation of very large numbers of files, and supporting efficient analysis. Several aspects of the API will be discussed in detail. First, we discuss the output data layout which linearizes the data in a consistent way that is independent of the number of processors used to run the simulation and provides a convenient format for subsequent analyses of the data. Second, we discuss the flexible API interface that enables modelers to easily add variables to the output stream by specifying where in the GCRM code these variables are located and to flexibly configure the choice of outputs and distribution of data across files. The flexibility of the API is designed to allow model developers to add new data fields to the output as the model develops and new physics is added and also provides a mechanism for allowing users of the GCRM code itself to adjust the output frequency and the number of fields written depending on the needs of individual calculations. Third, we describe the mapping to the NetCDF data model with an emphasis on the grid description. Fourth, we describe our messaging algorithms and IO aggregation strategies that are used to achieve high bandwidth while simultaneously writing concurrently from many processors to shared files. We conclude with initial performance results.

  15. Highly efficient spatial data filtering in parallel using the opensource library CPPPO

    NASA Astrophysics Data System (ADS)

    Municchi, Federico; Goniva, Christoph; Radl, Stefan

    2016-10-01

    CPPPO is a compilation of parallel data processing routines developed with the aim to create a library for "scale bridging" (i.e. connecting different scales by mean of closure models) in a multi-scale approach. CPPPO features a number of parallel filtering algorithms designed for use with structured and unstructured Eulerian meshes, as well as Lagrangian data sets. In addition, data can be processed on the fly, allowing the collection of relevant statistics without saving individual snapshots of the simulation state. Our library is provided with an interface to the widely-used CFD solver OpenFOAM®, and can be easily connected to any other software package via interface modules. Also, we introduce a novel, extremely efficient approach to parallel data filtering, and show that our algorithms scale super-linearly on multi-core clusters. Furthermore, we provide a guideline for choosing the optimal Eulerian cell selection algorithm depending on the number of CPU cores used. Finally, we demonstrate the accuracy and the parallel scalability of CPPPO in a showcase focusing on heat and mass transfer from a dense bed of particles. Catalogue identifier: AFAQ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AFAQ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU Lesser General Public License, version 3 No. of lines in distributed program, including test data, etc.: 1043965 No. of bytes in distributed program, including test data, etc.: 11053655 Distribution format: tar.gz Programming language: C++, MPI, octave. Computer: Linux based clusters for HPC or workstations. Operating system: Linux based. Classification: 4.14, 6.5, 12. External routines: Qt5, hdf5-1.8.15, jsonlab, OpenFOAM/CFDEM, Octave/Matlab Nature of problem: Development of closure models for momentum, species transport and heat transfer in fluid and fluid-particle systems using purely Eulerian or Euler-Lagrange simulators. Solution

  16. A simple hyperbolic model for communication in parallel processing environments

    NASA Technical Reports Server (NTRS)

    Stoica, Ion; Sultan, Florin; Keyes, David

    1994-01-01

    We introduce a model for communication costs in parallel processing environments called the 'hyperbolic model,' which generalizes two-parameter dedicated-link models in an analytically simple way. Dedicated interprocessor links parameterized by a latency and a transfer rate that are independent of load are assumed by many existing communication models; such models are unrealistic for workstation networks. The communication system is modeled as a directed communication graph in which terminal nodes represent the application processes that initiate the sending and receiving of the information and in which internal nodes, called communication blocks (CBs), reflect the layered structure of the underlying communication architecture. The direction of graph edges specifies the flow of the information carried through messages. Each CB is characterized by a two-parameter hyperbolic function of the message size that represents the service time needed for processing the message. The parameters are evaluated in the limits of very large and very small messages. Rules are given for reducing a communication graph consisting of many to an equivalent two-parameter form, while maintaining an approximation for the service time that is exact in both large and small limits. The model is validated on a dedicated Ethernet network of workstations by experiments with communication subprograms arising in scientific applications, for which a tight fit of the model predictions with actual measurements of the communication and synchronization time between end processes is demonstrated. The model is then used to evaluate the performance of two simple parallel scientific applications from partial differential equations: domain decomposition and time-parallel multigrid. In an appropriate limit, we also show the compatibility of the hyperbolic model with the recently proposed LogP model.

  17. Parallel processing of objects in a naming task.

    PubMed

    Meyer, Antje S; Ouellet, Marc; Häcker, Christine

    2008-07-01

    The authors investigated whether speakers who named several objects processed them sequentially or in parallel. Speakers named object triplets, arranged in a triangle, in the order left, right, and bottom object. The left object was easy or difficult to identify and name. During the saccade from the left to the right object, the right object shown at trial onset (the interloper) was replaced by a new object (the target), which the speakers named. Interloper and target were identical or unrelated objects, or they were conceptually unrelated objects with the same name (e.g., bat [animal] and [baseball] bat). The mean duration of the gazes to the target was shorter when interloper and target were identical or had the same name than when they were unrelated. The facilitatory effects of identical and homophonous interlopers were significantly larger when the left object was easy to process than when it was difficult to process. This interaction demonstrates that the speakers processed the left and right objects in parallel.

  18. A learnable parallel processing architecture towards unity of memory and computing

    NASA Astrophysics Data System (ADS)

    Li, H.; Gao, B.; Chen, Z.; Zhao, Y.; Huang, P.; Ye, H.; Liu, L.; Liu, X.; Kang, J.

    2015-08-01

    Developing energy-efficient parallel information processing systems beyond von Neumann architecture is a long-standing goal of modern information technologies. The widely used von Neumann computer architecture separates memory and computing units, which leads to energy-hungry data movement when computers work. In order to meet the need of efficient information processing for the data-driven applications such as big data and Internet of Things, an energy-efficient processing architecture beyond von Neumann is critical for the information society. Here we show a non-von Neumann architecture built of resistive switching (RS) devices named “iMemComp”, where memory and logic are unified with single-type devices. Leveraging nonvolatile nature and structural parallelism of crossbar RS arrays, we have equipped “iMemComp” with capabilities of computing in parallel and learning user-defined logic functions for large-scale information processing tasks. Such architecture eliminates the energy-hungry data movement in von Neumann computers. Compared with contemporary silicon technology, adder circuits based on “iMemComp” can improve the speed by 76.8% and the power dissipation by 60.3%, together with a 700 times aggressive reduction in the circuit area.

  19. A learnable parallel processing architecture towards unity of memory and computing.

    PubMed

    Li, H; Gao, B; Chen, Z; Zhao, Y; Huang, P; Ye, H; Liu, L; Liu, X; Kang, J

    2015-08-14

    Developing energy-efficient parallel information processing systems beyond von Neumann architecture is a long-standing goal of modern information technologies. The widely used von Neumann computer architecture separates memory and computing units, which leads to energy-hungry data movement when computers work. In order to meet the need of efficient information processing for the data-driven applications such as big data and Internet of Things, an energy-efficient processing architecture beyond von Neumann is critical for the information society. Here we show a non-von Neumann architecture built of resistive switching (RS) devices named "iMemComp", where memory and logic are unified with single-type devices. Leveraging nonvolatile nature and structural parallelism of crossbar RS arrays, we have equipped "iMemComp" with capabilities of computing in parallel and learning user-defined logic functions for large-scale information processing tasks. Such architecture eliminates the energy-hungry data movement in von Neumann computers. Compared with contemporary silicon technology, adder circuits based on "iMemComp" can improve the speed by 76.8% and the power dissipation by 60.3%, together with a 700 times aggressive reduction in the circuit area.

  20. A learnable parallel processing architecture towards unity of memory and computing.

    PubMed

    Li, H; Gao, B; Chen, Z; Zhao, Y; Huang, P; Ye, H; Liu, L; Liu, X; Kang, J

    2015-01-01

    Developing energy-efficient parallel information processing systems beyond von Neumann architecture is a long-standing goal of modern information technologies. The widely used von Neumann computer architecture separates memory and computing units, which leads to energy-hungry data movement when computers work. In order to meet the need of efficient information processing for the data-driven applications such as big data and Internet of Things, an energy-efficient processing architecture beyond von Neumann is critical for the information society. Here we show a non-von Neumann architecture built of resistive switching (RS) devices named "iMemComp", where memory and logic are unified with single-type devices. Leveraging nonvolatile nature and structural parallelism of crossbar RS arrays, we have equipped "iMemComp" with capabilities of computing in parallel and learning user-defined logic functions for large-scale information processing tasks. Such architecture eliminates the energy-hungry data movement in von Neumann computers. Compared with contemporary silicon technology, adder circuits based on "iMemComp" can improve the speed by 76.8% and the power dissipation by 60.3%, together with a 700 times aggressive reduction in the circuit area. PMID:26271243

  1. A learnable parallel processing architecture towards unity of memory and computing

    PubMed Central

    Li, H.; Gao, B.; Chen, Z.; Zhao, Y.; Huang, P.; Ye, H.; Liu, L.; Liu, X.; Kang, J.

    2015-01-01

    Developing energy-efficient parallel information processing systems beyond von Neumann architecture is a long-standing goal of modern information technologies. The widely used von Neumann computer architecture separates memory and computing units, which leads to energy-hungry data movement when computers work. In order to meet the need of efficient information processing for the data-driven applications such as big data and Internet of Things, an energy-efficient processing architecture beyond von Neumann is critical for the information society. Here we show a non-von Neumann architecture built of resistive switching (RS) devices named “iMemComp”, where memory and logic are unified with single-type devices. Leveraging nonvolatile nature and structural parallelism of crossbar RS arrays, we have equipped “iMemComp” with capabilities of computing in parallel and learning user-defined logic functions for large-scale information processing tasks. Such architecture eliminates the energy-hungry data movement in von Neumann computers. Compared with contemporary silicon technology, adder circuits based on “iMemComp” can improve the speed by 76.8% and the power dissipation by 60.3%, together with a 700 times aggressive reduction in the circuit area. PMID:26271243

  2. Smoldyn on graphics processing units: massively parallel Brownian dynamics simulations.

    PubMed

    Dematté, Lorenzo

    2012-01-01

    Space is a very important aspect in the simulation of biochemical systems; recently, the need for simulation algorithms able to cope with space is becoming more and more compelling. Complex and detailed models of biochemical systems need to deal with the movement of single molecules and particles, taking into consideration localized fluctuations, transportation phenomena, and diffusion. A common drawback of spatial models lies in their complexity: models can become very large, and their simulation could be time consuming, especially if we want to capture the systems behavior in a reliable way using stochastic methods in conjunction with a high spatial resolution. In order to deliver the promise done by systems biology to be able to understand a system as whole, we need to scale up the size of models we are able to simulate, moving from sequential to parallel simulation algorithms. In this paper, we analyze Smoldyn, a widely diffused algorithm for stochastic simulation of chemical reactions with spatial resolution and single molecule detail, and we propose an alternative, innovative implementation that exploits the parallelism of Graphics Processing Units (GPUs). The implementation executes the most computational demanding steps (computation of diffusion, unimolecular, and bimolecular reaction, as well as the most common cases of molecule-surface interaction) on the GPU, computing them in parallel on each molecule of the system. The implementation offers good speed-ups and real time, high quality graphics output

  3. Parallel processing at the SSC: The fact and the fiction

    SciTech Connect

    Bourianoff, G.; Cole, B.

    1991-10-01

    Accurately modelling the behavior of particles circulating in accelerators is a computationally demanding task. The particle tracking code currently in use at SSC is based upon a thin element'' analysis (TEAPOT). In this model each magnet in the lattice is described by a thin element at which the particle experiences an impulsive kick. Each kick requires approximately 200 floating point operations ( FLOP''). For the SSC collider lattice consisting of 10{sup 4} elements, performing a tracking of study for a set of 100 particles for 10{sup 7} turns would require 2 {times} 10{sup 15} FLOPS. Even on a machine capable of 100 MFLOP/sec (MFLOPS), this would require 2 {times} 10{sup 7} seconds, and many such runs are necessary. It should be noted that the accuracy with which the kicks are to be calculated is important: the large number of iterations involved will magnify the effects of small errors. The inability of current computational resources to effectively perform the full calculation motivates the migration of this calculation to the most powerful computers available. A survey of the current research into new technologies for superconducting reveals that the supercomputers of the future will be parallel in nature. Further, numerous such machines exist today, and are being used to solve other difficult problems. Thus it seems clear that it is not early to begin developing the capability to develop tracking codes for parallel architectures. This report discusses implementing parallel processing on the SCC.

  4. Parallel processing at the SSC: The fact and the fiction

    SciTech Connect

    Bourianoff, G.; Cole, B.

    1991-10-01

    Accurately modelling the behavior of particles circulating in accelerators is a computationally demanding task. The particle tracking code currently in use at SSC is based upon a ``thin element`` analysis (TEAPOT). In this model each magnet in the lattice is described by a thin element at which the particle experiences an impulsive kick. Each kick requires approximately 200 floating point operations (``FLOP``). For the SSC collider lattice consisting of 10{sup 4} elements, performing a tracking of study for a set of 100 particles for 10{sup 7} turns would require 2 {times} 10{sup 15} FLOPS. Even on a machine capable of 100 MFLOP/sec (MFLOPS), this would require 2 {times} 10{sup 7} seconds, and many such runs are necessary. It should be noted that the accuracy with which the kicks are to be calculated is important: the large number of iterations involved will magnify the effects of small errors. The inability of current computational resources to effectively perform the full calculation motivates the migration of this calculation to the most powerful computers available. A survey of the current research into new technologies for superconducting reveals that the supercomputers of the future will be parallel in nature. Further, numerous such machines exist today, and are being used to solve other difficult problems. Thus it seems clear that it is not early to begin developing the capability to develop tracking codes for parallel architectures. This report discusses implementing parallel processing on the SCC.

  5. Application of parallel distributed processing to space based systems

    NASA Technical Reports Server (NTRS)

    Macdonald, J. R.; Heffelfinger, H. L.

    1987-01-01

    The concept of using Parallel Distributed Processing (PDP) to enhance automated experiment monitoring and control is explored. Recent very large scale integration (VLSI) advances have made such applications an achievable goal. The PDP machine has demonstrated the ability to automatically organize stored information, handle unfamiliar and contradictory input data and perform the actions necessary. The PDP machine has demonstrated that it can perform inference and knowledge operations with greater speed and flexibility and at lower cost than traditional architectures. In applications where the rule set governing an expert system's decisions is difficult to formulate, PDP can be used to extract rules by associating the information an expert receives with the actions taken.

  6. Parallel-Processing Software for Creating Mosaic Images

    NASA Technical Reports Server (NTRS)

    Klimeck, Gerhard; Deen, Robert; McCauley, Michael; DeJong, Eric

    2008-01-01

    A computer program implements parallel processing for nearly real-time creation of panoramic mosaics of images of terrain acquired by video cameras on an exploratory robotic vehicle (e.g., a Mars rover). Because the original images are typically acquired at various camera positions and orientations, it is necessary to warp the images into the reference frame of the mosaic before stitching them together to create the mosaic. [Also see "Parallel-Processing Software for Correlating Stereo Images," Software Supplement to NASA Tech Briefs, Vol. 31, No. 9 (September 2007) page 26.] The warping algorithm in this computer program reflects the considerations that (1) for every pixel in the desired final mosaic, a good corresponding point must be found in one or more of the original images and (2) for this purpose, one needs a good mathematical model of the cameras and a good correlation of individual pixels with respect to their positions in three dimensions. The desired mosaic is divided into slices, each of which is assigned to one of a number of central processing units (CPUs) operating simultaneously. The results from the CPUs are gathered and placed into the final mosaic. The time taken to create the mosaic depends upon the number of CPUs, the speed of each CPU, and whether a local or a remote data-staging mechanism is used.

  7. Parallel deterioration to language processing in a bilingual speaker.

    PubMed

    Druks, Judit; Weekes, Brendan Stuart

    2013-01-01

    The convergence hypothesis [Green, D. W. (2003). The neural basis of the lexicon and the grammar in L2 acquisition: The convergence hypothesis. In R. van Hout, A. Hulk, F. Kuiken, & R. Towell (Eds.), The interface between syntax and the lexicon in second language acquisition (pp. 197-218). Amsterdam: John Benjamins] assumes that the neural substrates of language representations are shared between the languages of a bilingual speaker. One prediction of this hypothesis is that neurodegenerative disease should produce parallel deterioration to lexical and grammatical processing in bilingual aphasia. We tested this prediction with a late bilingual Hungarian (first language, L1)-English (second language, L2) speaker J.B. who had nonfluent progressive aphasia (NFPA). J.B. had acquired L2 in adolescence but was premorbidly proficient and used English as his dominant language throughout adult life. Our investigations showed comparable deterioration to lexical and grammatical knowledge in both languages during a one-year period. Parallel deterioration to language processing in a bilingual speaker with NFPA challenges the assumption that L1 and L2 rely on different brain mechanisms as assumed in some theories of bilingual language processing [Ullman, M. T. (2001). The neural basis of lexicon and grammar in first and second language: The declarative/procedural model. Bilingualism: Language and Cognition, 4(1), 105-122]. PMID:24527801

  8. Parallel deterioration to language processing in a bilingual speaker.

    PubMed

    Druks, Judit; Weekes, Brendan Stuart

    2013-01-01

    The convergence hypothesis [Green, D. W. (2003). The neural basis of the lexicon and the grammar in L2 acquisition: The convergence hypothesis. In R. van Hout, A. Hulk, F. Kuiken, & R. Towell (Eds.), The interface between syntax and the lexicon in second language acquisition (pp. 197-218). Amsterdam: John Benjamins] assumes that the neural substrates of language representations are shared between the languages of a bilingual speaker. One prediction of this hypothesis is that neurodegenerative disease should produce parallel deterioration to lexical and grammatical processing in bilingual aphasia. We tested this prediction with a late bilingual Hungarian (first language, L1)-English (second language, L2) speaker J.B. who had nonfluent progressive aphasia (NFPA). J.B. had acquired L2 in adolescence but was premorbidly proficient and used English as his dominant language throughout adult life. Our investigations showed comparable deterioration to lexical and grammatical knowledge in both languages during a one-year period. Parallel deterioration to language processing in a bilingual speaker with NFPA challenges the assumption that L1 and L2 rely on different brain mechanisms as assumed in some theories of bilingual language processing [Ullman, M. T. (2001). The neural basis of lexicon and grammar in first and second language: The declarative/procedural model. Bilingualism: Language and Cognition, 4(1), 105-122].

  9. XTP as a transport protocol for distributed parallel processing

    SciTech Connect

    Strayer, W.T.; Lewis, M.J.; Cline, R.E. Jr.

    1994-12-31

    The Xpress Transfer Protocol (XTP) is a flexible transport layer protocol designed to provide efficient service without dictating the communication paradigm or the delivery characteristics that quality the paradigm. XTP provides the tools to build communication services appropriate to the application. Current data delivery solutions for many popular cluster computing environments use TCP and UDP. We examine TCP, UDP, and XTP with respect to the communication characteristics typical of parallel applications. We perform measurements of end-to-end latency for several paradigms important to cluster computing. An implementation of XTP is shown to be comparable to TCP in end-to-end latency on preestablished connections, and does better for paradigms where connections must be constructed on the fly.

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

    NASA Astrophysics Data System (ADS)

    Jeon, Byoungseon; Grønbech-Jensen, Niels

    2009-02-01

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

  11. Parallel Latent Semantic Analysis using a Graphics Processing Unit

    SciTech Connect

    Cui, Xiaohui; Potok, Thomas E; Cavanagh, Joseph M

    2009-01-01

    Latent Semantic Analysis (LSA) can be used to reduce the dimensions of large Term-Document datasets using Singular Value Decomposition. However, with the ever expanding size of data sets, current implementations are not fast enough to quickly and easily compute the results on a standard PC. The Graphics Processing Unit (GPU) can solve some highly parallel problems much faster than the traditional sequential processor (CPU). Thus, a deployable system using a GPU to speedup large-scale LSA processes would be a much more effective choice (in terms of cost/performance ratio) than using a computer cluster. In this paper, we presented a parallel LSA implementation on the GPU, using NVIDIA Compute Unified Device Architecture (CUDA) and Compute Unified Basic Linear Algebra Subprograms (CUBLAS). The performance of this implementation is compared to traditional LSA implementation on CPU using an optimized Basic Linear Algebra Subprograms library. For large matrices that have dimensions divisible by 16, the GPU algorithm ran five to six times faster than the CPU version.

  12. Beta operations: efficient implementation of a primitive parallel operation. Technical report

    SciTech Connect

    Cohn, E.R.; Haddad, R.W.

    1986-08-01

    The ever-decreasing cost of computer processors has created a great interest in multi-processor computers. However, along with the increased power that this parallelism brings comes increased complexity in programming. One approach to lessening this complexity is to provide the programmer with general-purpose parallel primitives that shield him from the structure of the underlying machine. In The Connection Machine, Hillis suggests the beta operation as a parallel primitive for his hypercube-based machine. This paper explores efficient ways to perform this operation on several different well known architectures, including the hypercube. It presents some lower bounds associated with the problem.

  13. Parallel processing architecture for H.264 deblocking filter on multi-core platforms

    NASA Astrophysics Data System (ADS)

    Prasad, Durga P.; Sonachalam, Sekar; Kunchamwar, Mangesh K.; Gunupudi, Nageswara Rao

    2012-03-01

    Massively parallel computing (multi-core) chips offer outstanding new solutions that satisfy the increasing demand for high resolution and high quality video compression technologies such as H.264. Such solutions not only provide exceptional quality but also efficiency, low power, and low latency, previously unattainable in software based designs. While custom hardware and Application Specific Integrated Circuit (ASIC) technologies may achieve lowlatency, low power, and real-time performance in some consumer devices, many applications require a flexible and scalable software-defined solution. The deblocking filter in H.264 encoder/decoder poses difficult implementation challenges because of heavy data dependencies and the conditional nature of the computations. Deblocking filter implementations tend to be fixed and difficult to reconfigure for different needs. The ability to scale up for higher quality requirements such as 10-bit pixel depth or a 4:2:2 chroma format often reduces the throughput of a parallel architecture designed for lower feature set. A scalable architecture for deblocking filtering, created with a massively parallel processor based solution, means that the same encoder or decoder will be deployed in a variety of applications, at different video resolutions, for different power requirements, and at higher bit-depths and better color sub sampling patterns like YUV, 4:2:2, or 4:4:4 formats. Low power, software-defined encoders/decoders may be implemented using a massively parallel processor array, like that found in HyperX technology, with 100 or more cores and distributed memory. The large number of processor elements allows the silicon device to operate more efficiently than conventional DSP or CPU technology. This software programing model for massively parallel processors offers a flexible implementation and a power efficiency close to that of ASIC solutions. This work describes a scalable parallel architecture for an H.264 compliant deblocking

  14. MASSIVELY PARALLEL LATENT SEMANTIC ANALYSES USING A GRAPHICS PROCESSING UNIT

    SciTech Connect

    Cavanagh, J.; Cui, S.

    2009-01-01

    Latent Semantic Analysis (LSA) aims to reduce the dimensions of large term-document datasets using Singular Value Decomposition. However, with the ever-expanding size of datasets, current implementations are not fast enough to quickly and easily compute the results on a standard PC. A graphics processing unit (GPU) can solve some highly parallel problems much faster than a traditional sequential processor or central processing unit (CPU). Thus, a deployable system using a GPU to speed up large-scale LSA processes would be a much more effective choice (in terms of cost/performance ratio) than using a PC cluster. Due to the GPU’s application-specifi c architecture, harnessing the GPU’s computational prowess for LSA is a great challenge. We presented a parallel LSA implementation on the GPU, using NVIDIA® Compute Unifi ed Device Architecture and Compute Unifi ed Basic Linear Algebra Subprograms software. The performance of this implementation is compared to traditional LSA implementation on a CPU using an optimized Basic Linear Algebra Subprograms library. After implementation, we discovered that the GPU version of the algorithm was twice as fast for large matrices (1 000x1 000 and above) that had dimensions not divisible by 16. For large matrices that did have dimensions divisible by 16, the GPU algorithm ran fi ve to six times faster than the CPU version. The large variation is due to architectural benefi ts of the GPU for matrices divisible by 16. It should be noted that the overall speeds for the CPU version did not vary from relative normal when the matrix dimensions were divisible by 16. Further research is needed in order to produce a fully implementable version of LSA. With that in mind, the research we presented shows that the GPU is a viable option for increasing the speed of LSA, in terms of cost/performance ratio.

  15. Massively Parallel Processing for Fast and Accurate Stamping Simulations

    NASA Astrophysics Data System (ADS)

    Gress, Jeffrey J.; Xu, Siguang; Joshi, Ramesh; Wang, Chuan-tao; Paul, Sabu

    2005-08-01

    The competitive automotive market drives automotive manufacturers to speed up the vehicle development cycles and reduce the lead-time. Fast tooling development is one of the key areas to support fast and short vehicle development programs (VDP). In the past ten years, the stamping simulation has become the most effective validation tool in predicting and resolving all potential formability and quality problems before the dies are physically made. The stamping simulation and formability analysis has become an critical business segment in GM math-based die engineering process. As the simulation becomes as one of the major production tools in engineering factory, the simulation speed and accuracy are the two of the most important measures for stamping simulation technology. The speed and time-in-system of forming analysis becomes an even more critical to support the fast VDP and tooling readiness. Since 1997, General Motors Die Center has been working jointly with our software vendor to develop and implement a parallel version of simulation software for mass production analysis applications. By 2001, this technology was matured in the form of distributed memory processing (DMP) of draw die simulations in a networked distributed memory computing environment. In 2004, this technology was refined to massively parallel processing (MPP) and extended to line die forming analysis (draw, trim, flange, and associated spring-back) running on a dedicated computing environment. The evolution of this technology and the insight gained through the implementation of DM0P/MPP technology as well as performance benchmarks are discussed in this publication.

  16. Parallel information processing channels created in the retina.

    PubMed

    Schiller, Peter H

    2010-10-01

    In the retina, several parallel channels originate that extract different attributes from the visual scene. This review describes how these channels arise and what their functions are. Following the introduction four sections deal with these channels. The first discusses the "ON" and "OFF" channels that have arisen for the purpose of rapidly processing images in the visual scene that become visible by virtue of either light increment or light decrement; the ON channel processes images that become visible by virtue of light increment and the OFF channel processes images that become visible by virtue of light decrement. The second section examines the midget and parasol channels. The midget channel processes fine detail, wavelength information, and stereoscopic depth cues; the parasol channel plays a central role in processing motion and flicker as well as motion parallax cues for depth perception. Both these channels have ON and OFF subdivisions. The third section describes the accessory optic system that receives input from the retinal ganglion cells of Dogiel; these cells play a central role, in concert with the vestibular system, in stabilizing images on the retina to prevent the blurring of images that would otherwise occur when an organism is in motion. The last section provides a brief overview of several additional channels that originate in the retina.

  17. Parallel information processing channels created in the retina

    PubMed Central

    Schiller, Peter H.

    2010-01-01

    In the retina, several parallel channels originate that extract different attributes from the visual scene. This review describes how these channels arise and what their functions are. Following the introduction four sections deal with these channels. The first discusses the “ON” and “OFF” channels that have arisen for the purpose of rapidly processing images in the visual scene that become visible by virtue of either light increment or light decrement; the ON channel processes images that become visible by virtue of light increment and the OFF channel processes images that become visible by virtue of light decrement. The second section examines the midget and parasol channels. The midget channel processes fine detail, wavelength information, and stereoscopic depth cues; the parasol channel plays a central role in processing motion and flicker as well as motion parallax cues for depth perception. Both these channels have ON and OFF subdivisions. The third section describes the accessory optic system that receives input from the retinal ganglion cells of Dogiel; these cells play a central role, in concert with the vestibular system, in stabilizing images on the retina to prevent the blurring of images that would otherwise occur when an organism is in motion. The last section provides a brief overview of several additional channels that originate in the retina. PMID:20876118

  18. Development of an aerodynamics algorithm for parallel-processing supercomputers

    NASA Technical Reports Server (NTRS)

    Swisshelm, Julie M.; Johnson, Gary M.

    1988-01-01

    An explicit flow solver, applicable to the hierarchy of model equations ranging from Euler to full Navier-Stokes, is combined with several techniques designed to reduce computational expense. The computational domain consists of local grid refinements embedded in a global coarse mesh, where the locations of these refinements are defined by the physics of the flow. Flow characteristics are also used to determine which set of model equations is appropriate for solution in each region, thereby reducing not only the number of grid points at which the solution must be obtained, but also the computational effort required to get that solution. Acceleration to steady-state is achieved by applying multigrid on each of the subgrids, regardless of the particular model equations being solved. Since each of these components is explicit, advantage can readily be taken of the vector- and parallel-processing capabilities of machines such as the Cray X-MP and Cray-2.

  19. Safety-oriented global analysis and parallel processing

    SciTech Connect

    Dinca, L.G.; Aldemir, T.

    1994-12-31

    The objective of safety-oriented global analysis (SOGA) is to determine the conditions under which the evolution of a dynamic system in time remains within the imposed constraints in view of the uncertainties on the system parameters and/or the observed systern state. Often the only generally applicable SOGA method for nonlinear systems is the direct integration of the governing equations, which can be computationally prohibitive. An alternative SOGA methodology has been under dridopment at the Ohio State University (OSU), and its application to reactor dynamics has been illustrated in previous presentations. In spite of the computational advantage of the OSU methodology over direct integration, the computational time and storage requirements are still limiting factors in implementation. A procedure to reduce the storage requirements was presented earlier. This paper describes how the computational time can be reduced using parallel processing.

  20. Parallel Processing of Adaptive Meshes with Load Balancing

    NASA Technical Reports Server (NTRS)

    Das, Sajal K.; Harvey, Daniel J.; Biswas, Rupak; Biegel, Bryan (Technical Monitor)

    2001-01-01

    Many scientific applications involve grids that lack a uniform underlying structure. These applications are often also dynamic in nature in that the grid structure significantly changes between successive phases of execution. In parallel computing environments, mesh adaptation of unstructured grids through selective refinement/coarsening has proven to be an effective approach. However, achieving load balance while minimizing interprocessor communication and redistribution costs is a difficult problem. Traditional dynamic load balancers are mostly inadequate because they lack a global view of system loads across processors. In this paper, we propose a novel and general-purpose load balancer that utilizes symmetric broadcast networks (SBN) as the underlying communication topology, and compare its performance with a successful global load balancing environment, called PLUM, specifically created to handle adaptive unstructured applications. Our experimental results on an IBM SP2 demonstrate that the SBN-based load balancer achieves lower redistribution costs than that under PLUM by overlapping processing and data migration.

  1. Applying the Extended Parallel Process Model to workplace safety messages.

    PubMed

    Basil, Michael; Basil, Debra; Deshpande, Sameer; Lavack, Anne M

    2013-01-01

    The extended parallel process model (EPPM) proposes fear appeals are most effective when they combine threat and efficacy. Three studies conducted in the workplace safety context examine the use of various EPPM factors and their effects, especially multiplicative effects. Study 1 was a content analysis examining the use of EPPM factors in actual workplace safety messages. Study 2 experimentally tested these messages with 212 construction trainees. Study 3 replicated this experiment with 1,802 men across four English-speaking countries-Australia, Canada, the United Kingdom, and the United States. The results of these three studies (1) demonstrate the inconsistent use of EPPM components in real-world work safety communications, (2) support the necessity of self-efficacy for the effective use of threat, (3) show a multiplicative effect where communication effectiveness is maximized when all model components are present (severity, susceptibility, and efficacy), and (4) validate these findings with gory appeals across four English-speaking countries.

  2. Parallel asynchronous hardware implementation of image processing algorithms

    NASA Technical Reports Server (NTRS)

    Coon, Darryl D.; Perera, A. G. U.

    1990-01-01

    Research is being carried out on hardware for a new approach to focal plane processing. The hardware involves silicon injection mode devices. These devices provide a natural basis for parallel asynchronous focal plane image preprocessing. The simplicity and novel properties of the devices would permit an independent analog processing channel to be dedicated to every pixel. A laminar architecture built from arrays of the devices would form a two-dimensional (2-D) array processor with a 2-D array of inputs located directly behind a focal plane detector array. A 2-D image data stream would propagate in neuron-like asynchronous pulse-coded form through the laminar processor. No multiplexing, digitization, or serial processing would occur in the preprocessing state. High performance is expected, based on pulse coding of input currents down to one picoampere with noise referred to input of about 10 femtoamperes. Linear pulse coding has been observed for input currents ranging up to seven orders of magnitude. Low power requirements suggest utility in space and in conjunction with very large arrays. Very low dark current and multispectral capability are possible because of hardware compatibility with the cryogenic environment of high performance detector arrays. The aforementioned hardware development effort is aimed at systems which would integrate image acquisition and image processing.

  3. Massively Parallel Latent Semantic Analyzes using a Graphics Processing Unit

    SciTech Connect

    Cavanagh, Joseph M; Cui, Xiaohui

    2009-01-01

    Latent Semantic Indexing (LSA) aims to reduce the dimensions of large Term-Document datasets using Singular Value Decomposition. However, with the ever expanding size of data sets, current implementations are not fast enough to quickly and easily compute the results on a standard PC. The Graphics Processing Unit (GPU) can solve some highly parallel problems much faster than the traditional sequential processor (CPU). Thus, a deployable system using a GPU to speedup large-scale LSA processes would be a much more effective choice (in terms of cost/performance ratio) than using a computer cluster. Due to the GPU s application-specific architecture, harnessing the GPU s computational prowess for LSA is a great challenge. We present a parallel LSA implementation on the GPU, using NVIDIA Compute Unified Device Architecture and Compute Unified Basic Linear Algebra Subprograms. The performance of this implementation is compared to traditional LSA implementation on CPU using an optimized Basic Linear Algebra Subprograms library. After implementation, we discovered that the GPU version of the algorithm was twice as fast for large matrices (1000x1000 and above) that had dimensions not divisible by 16. For large matrices that did have dimensions divisible by 16, the GPU algorithm ran five to six times faster than the CPU version. The large variation is due to architectural benefits the GPU has for matrices divisible by 16. It should be noted that the overall speeds for the CPU version did not vary from relative normal when the matrix dimensions were divisible by 16. Further research is needed in order to produce a fully implementable version of LSA. With that in mind, the research we presented shows that the GPU is a viable option for increasing the speed of LSA, in terms of cost/performance ratio.

  4. Efficient parallel solution of parabolic equations - Implicit methods on the Cedar multicluster

    NASA Technical Reports Server (NTRS)

    Gallopoulos, E.; Saad, Y.

    1990-01-01

    A class of implicit methods for the parallel solution of linear parabolic differential equations based on Pade and Chebyshev rational approximations to the matrix exponential are presented. It is pointed out that this approach incorporates both natural hierarchical parallelism, improved intrinsic efficiency, and fewer timesteps. These advantages lead to an extremely fast family of methods for the solution of certain time-dependent problems. These techniques are illustrated with numerical experiments on the University of Illinois Cedar multicluster architecture. The experiments indicate that implicit methods of very high degree offer great promise for the solution of certain parabolic problems when in computational environment with parallel resources. Hierarchically organized parallel computers, such as the Cedar multicluster, are found to be especially attractive for these schemes.

  5. Real-time hybrid joint transform correlator with parallel processing architecture

    NASA Astrophysics Data System (ADS)

    Qin, Yuwen; Ge, Bao-Zhen; Zhang, Yimo; Zhao, Xiao-Dong; Huang, Zhanhua

    1996-12-01

    A real-time hybrid joint transform correlator (JTC) with parallel processing architecture that use two liquid crystal light valves spatial light modulators, two VP32 image boards and two optical wavefront-division multiplexers as the key parts was presented. Using this hybrid JTC< real-time high- efficiency joint transform correlation, high-speed joint transform correlation and four-channel joint transform correlation were realized. The hybrid JTC system has also been used in the domain of morphological complex-valued kernel scale-space image processing. In this paper, the principles of the above experiments are described, experimental results are also given and analyzed.

  6. Efficient parallelization of analytic bond-order potentials for large-scale atomistic simulations

    NASA Astrophysics Data System (ADS)

    Teijeiro, C.; Hammerschmidt, T.; Drautz, R.; Sutmann, G.

    2016-07-01

    Analytic bond-order potentials (BOPs) provide a way to compute atomistic properties with controllable accuracy. For large-scale computations of heterogeneous compounds at the atomistic level, both the computational efficiency and memory demand of BOP implementations have to be optimized. Since the evaluation of BOPs is a local operation within a finite environment, the parallelization concepts known from short-range interacting particle simulations can be applied to improve the performance of these simulations. In this work, several efficient parallelization methods for BOPs that use three-dimensional domain decomposition schemes are described. The schemes are implemented into the bond-order potential code BOPfox, and their performance is measured in a series of benchmarks. Systems of up to several millions of atoms are simulated on a high performance computing system, and parallel scaling is demonstrated for up to thousands of processors.

  7. Mobile Devices and GPU Parallelism in Ionospheric Data Processing

    NASA Astrophysics Data System (ADS)

    Mascharka, D.; Pankratius, V.

    2015-12-01

    Scientific data acquisition in the field is often constrained by data transfer backchannels to analysis environments. Geoscientists are therefore facing practical bottlenecks with increasing sensor density and variety. Mobile devices, such as smartphones and tablets, offer promising solutions to key problems in scientific data acquisition, pre-processing, and validation by providing advanced capabilities in the field. This is due to affordable network connectivity options and the increasing mobile computational power. This contribution exemplifies a scenario faced by scientists in the field and presents the "Mahali TEC Processing App" developed in the context of the NSF-funded Mahali project. Aimed at atmospheric science and the study of ionospheric Total Electron Content (TEC), this app is able to gather data from various dual-frequency GPS receivers. It demonstrates parsing of full-day RINEX files on mobile devices and on-the-fly computation of vertical TEC values based on satellite ephemeris models that are obtained from NASA. Our experiments show how parallel computing on the mobile device GPU enables fast processing and visualization of up to 2 million datapoints in real-time using OpenGL. GPS receiver bias is estimated through minimum TEC approximations that can be interactively adjusted by scientists in the graphical user interface. Scientists can also perform approximate computations for "quickviews" to reduce CPU processing time and memory consumption. In the final stage of our mobile processing pipeline, scientists can upload data to the cloud for further processing. Acknowledgements: The Mahali project (http://mahali.mit.edu) is funded by the NSF INSPIRE grant no. AGS-1343967 (PI: V. Pankratius). We would like to acknowledge our collaborators at Boston College, Virginia Tech, Johns Hopkins University, Colorado State University, as well as the support of UNAVCO for loans of dual-frequency GPS receivers for use in this project, and Intel for loans of

  8. Radon-Based Image Processing In A Parallel Pipeline Architecture

    NASA Astrophysics Data System (ADS)

    Hinkle, Eric B.; Sanz, Jorge L. C.; Jain, Anil K.

    1986-04-01

    This paper deals with a novel architecture that makes real-time projection-based algorithms a reality. The design is founded on raster-mode processing, which is exploited in a powerful and flexible pipeline. This architecture, dubbed "P3 E" ( Parallel Pipeline Projection Engine), supports a large variety of image processing and image analysis applications. The image processing applications include: discrete approximations of the Radon and inverse Radon transform, among other projection operators; CT reconstructions; 2-D convolutions; rotations and translations; discrete Fourier transform computations in polar coordinates; autocorrelations; etc. There is also an extensive list of key image analysis algorithms that are supported by P E, thus making it a profound and versatile tool for projection-based computer vision. These include: projections of gray-level images along linear patterns (the Radon transform) and other curved contours; generation of multi-color digital masks; convex hull approximations; Hough transform approximations for line and curve detection; diameter computations; calculations of moments and other principal components; etc. The effectiveness of our approach and the feasibility of the proposed architecture have been demonstrated by running some of these image analysis algorithms in conventional short pipelines, to solve some important automated inspection problems. In the present paper, we will concern ourselves with reconstructing images from their linear projections, and performing convolutions via the Radon transform.

  9. SIMD massively parallel processing system for real-time image processing

    NASA Astrophysics Data System (ADS)

    Chen, Xiaochu; Zhang, Ming; Yao, Qingdong; Liu, Jilin; Ye, Hong; Wu, Song; Li, Dongxiao; Zhang, Yong; Ding, Lei; Yao, Zhongyang; Yang, Weijian; Pan, Qiaohai

    1998-09-01

    This paper will describe the embedded SIMD massively parallel processor that we have developed for real-time image processing applications, such as real-time small target detection and tracking and video processing. The processor array is based on SIMD chip BAP-128 designed by our own, and uses high performance DSP TMS320C31, which can effectively perform serial and floating point calculations, as the host of the SIMD processor array. As a result, the system is able to perform a variety of image processing tasks in real-time. Furthermore, the processor will be connected with a MIMD parallel processor to construct a heterogeneously parallel processor for more complex real- time ATR (Automatic Target Recognition) and computer vision applications.

  10. On the design and implementation of a parallel, object-oriented, image processing toolkit

    SciTech Connect

    Kamath, C; Baldwin, C; Fodor, I; Tang, N A

    2000-06-22

    Advanced in technology have enabled us to collect data from observations, experiments, and simulations at an ever increasing pace. As these data sets approach the terabyte and petabyte range, scientists are increasingly using semi-automated techniques from data mining and pattern recognition to find useful information in the data. In order for data mining to be successful, the raw data must first be processed into a form suitable for the detection of patterns. When the data is in the form of images, this can involve a substantial amount of processing on very large data sets. To help make this task more efficient, they are designing and implementing an object-oriented image processing toolkit that specifically targets massively-parallel, distributed-memory architectures. They first show that it is possible to use object-oriented technology to effectively address the diverse needs of image applications. Next, they describe how we abstract out the similarities in image processing algorithms to enable re-use in the software. They will also discuss the difficulties encountered in parallelizing image algorithms on massively parallel machines as well as the bottlenecks to high performance. They will demonstrate the work using images from an astronomical data set, and illustrate how techniques such as filters and denoising through the thresholding of wavelet coefficients can be applied when a large image is distributed across several processors.

  11. Resolving Multiscale Processes in Tropical Cyclogenesis Using Parallel EEMD

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Shen, B. W.; Cheung, S.; Li, J. L. F.; Liu, Z.

    2014-12-01

    The recent advance in high-resolution global models has suggested that improved multiscale simulations of tropical waves may help extend the lead time of tropical cyclone (TC) formation prediction (e.g., Shen et al., 2010ab, 2012, 2013a). In previous efforts in the multiscale analysis of tropical waves , the Ensemble Empirical Mode Decomposition (EEMD) has been successfully parallelized and used to detect atmospheric wave signals on different spatial scales (e.g. Shen et al., 2013b) that include Mixed Rossby Gravity (MRG) waves, Western Wind Belt (WWB), African Easterly Waves (AEWs), etc. We now extend the related studies to examine the evolution of the large scale waves and their association with the formation of tropical cyclones in the Atlantic for an extensive time period spanning multiple years. Our goal is to analyze the multiscale interaction in the initiation and early intensification stage of an AEW and its subsequent impact on TC genesis that involves mainly the large scale downscaling processes. Specific focus is on the impact of barotropic instability and critical level (CL, or steering level) that may appear in association with the AEW. The presence of the CL is believed to play an important role in providing a favorable environment in the early TC-genesis stage in the marsupial paradigm scenario. Preliminary analysis of the satellite data obtained from the newly launched Global Precipitation Measurement (GPM) mission linked to the TC genesis processes will be included.

  12. Endpoint-based parallel data processing with non-blocking collective instructions in a parallel active messaging interface of a parallel computer

    DOEpatents

    Archer, Charles J; Blocksome, Michael A; Cernohous, Bob R; Ratterman, Joseph D; Smith, Brian E

    2014-11-18

    Methods, apparatuses, and computer program products for endpoint-based parallel data processing with non-blocking collective instructions in a parallel active messaging interface (`PAMI`) of a parallel computer are provided. Embodiments include establishing by a parallel application a data communications geometry, the geometry specifying a set of endpoints that are used in collective operations of the PAMI, including associating with the geometry a list of collective algorithms valid for use with the endpoints of the geometry. Embodiments also include registering in each endpoint in the geometry a dispatch callback function for a collective operation and executing without blocking, through a single one of the endpoints in the geometry, an instruction for the collective operation.

  13. An efficient parallel algorithm for the solution of a tridiagonal linear system of equations

    NASA Technical Reports Server (NTRS)

    Stone, H. S.

    1971-01-01

    Tridiagonal linear systems of equations are solved on conventional serial machines in a time proportional to N, where N is the number of equations. The conventional algorithms do not lend themselves directly to parallel computations on computers of the ILLIAC IV class, in the sense that they appear to be inherently serial. An efficient parallel algorithm is presented in which computation time grows as log sub 2 N. The algorithm is based on recursive doubling solutions of linear recurrence relations, and can be used to solve recurrence relations of all orders.

  14. An efficient parallel algorithm for the solution of a tridiagonal linear system of equations.

    NASA Technical Reports Server (NTRS)

    Stone, H. S.

    1973-01-01

    Tridiagonal linear systems of equations can be solved on conventional serial machines in a time proportional to N, where N is the number of equations. The conventional algorithms do not lend themselves directly to parallel computation on computers of the Illiac IV class, in the sense that they appear to be inherently serial. An efficient parallel algorithm is presented in which computation time grows as log(sub-2) N. The algorithm is based on recursive doubling solutions of linear recurrence relations, and can be used to solve recurrence relations of all orders.

  15. Efficient Extraction of Regional Subsets from Massive Climate Datasets using Parallel IO

    SciTech Connect

    Daily, Jeffrey A.; Schuchardt, Karen L.; Palmer, Bruce J.

    2010-09-16

    The size of datasets produced by current climate models is increasing rapidly to the scale of petabytes. To handle data at this scale parallel analysis tools are required, however the majority of climate analysis software remains at the scale of workstations. Further, many climate analysis tools adequately process regularly gridded data but lack sufficient features when handling unstructured grids. This paper presents a data-parallel subsetter capable of correctly handling unstructured grids while scaling to over 2000 cores. The approach is based on the partitioned global address space (PGAS) parallel programming model and one-sided communication. The paper demonstrates that IO remains the single greatest bottleneck for this domain of applications and that parallel analysis of climate data succeeds in practice.

  16. Parallel processing using an optical delay-based reservoir computer

    NASA Astrophysics Data System (ADS)

    Van der Sande, Guy; Nguimdo, Romain Modeste; Verschaffelt, Guy

    2016-04-01

    Delay systems subject to delayed optical feedback have recently shown great potential in solving computationally hard tasks. By implementing a neuro-inspired computational scheme relying on the transient response to optical data injection, high processing speeds have been demonstrated. However, reservoir computing systems based on delay dynamics discussed in the literature are designed by coupling many different stand-alone components which lead to bulky, lack of long-term stability, non-monolithic systems. Here we numerically investigate the possibility of implementing reservoir computing schemes based on semiconductor ring lasers. Semiconductor ring lasers are semiconductor lasers where the laser cavity consists of a ring-shaped waveguide. SRLs are highly integrable and scalable, making them ideal candidates for key components in photonic integrated circuits. SRLs can generate light in two counterpropagating directions between which bistability has been demonstrated. We demonstrate that two independent machine learning tasks , even with different nature of inputs with different input data signals can be simultaneously computed using a single photonic nonlinear node relying on the parallelism offered by photonics. We illustrate the performance on simultaneous chaotic time series prediction and a classification of the Nonlinear Channel Equalization. We take advantage of different directional modes to process individual tasks. Each directional mode processes one individual task to mitigate possible crosstalk between the tasks. Our results indicate that prediction/classification with errors comparable to the state-of-the-art performance can be obtained even with noise despite the two tasks being computed simultaneously. We also find that a good performance is obtained for both tasks for a broad range of the parameters. The results are discussed in detail in [Nguimdo et al., IEEE Trans. Neural Netw. Learn. Syst. 26, pp. 3301-3307, 2015

  17. Fast phase processing in off-axis holography by CUDA including parallel phase unwrapping.

    PubMed

    Backoach, Ohad; Kariv, Saar; Girshovitz, Pinhas; Shaked, Natan T

    2016-02-22

    We present parallel processing implementation for rapid extraction of the quantitative phase maps from off-axis holograms on the Graphics Processing Unit (GPU) of the computer using computer unified device architecture (CUDA) programming. To obtain efficient implementation, we parallelized both the wrapped phase map extraction algorithm and the two-dimensional phase unwrapping algorithm. In contrast to previous implementations, we utilized unweighted least squares phase unwrapping algorithm that better suits parallelism. We compared the proposed algorithm run times on the CPU and the GPU of the computer for various sizes of off-axis holograms. Using the GPU implementation, we extracted the unwrapped phase maps from the recorded off-axis holograms at 35 frames per second (fps) for 4 mega pixel holograms, and at 129 fps for 1 mega pixel holograms, which presents the fastest processing framerates obtained so far, to the best of our knowledge. We then used common-path off-axis interferometric imaging to quantitatively capture the phase maps of a micro-organism with rapid flagellum movements. PMID:26906982

  18. Parallel performance of the fine-grain pipeline FPGA image processing system

    NASA Astrophysics Data System (ADS)

    Gorgoń, M.

    2012-06-01

    The use of FPGA circuits in imaging systems increases. They compete with other computing environments. The article describes the indications to be followed while choosing the type of image processing computing system taking under consideration the advantages and disadvantages of each technology: general purpose processor, digital signal processor, graphical processing unit, application specific Integrated circuit and field programmable gate array. Attention is drawn to various video transmission standards. The state of research and development trends in the field of FPGA-based image processing are briefly presented. A defining processing performance method for image processing is proposed. It is proven that for a pipeline architecture implemented in FPGA, a linear speedup is achieved and parallel efficiency is equal to one.

  19. Parallel processing methods for space based power systems

    NASA Technical Reports Server (NTRS)

    Berry, F. C.

    1993-01-01

    This report presents a method for doing load-flow analysis of a power system by using a decomposition approach. The power system for the Space Shuttle is used as a basis to build a model for the load-flow analysis. To test the decomposition method for doing load-flow analysis, simulations were performed on power systems of 16, 25, 34, 43, 52, 61, 70, and 79 nodes. Each of the power systems was divided into subsystems and simulated under steady-state conditions. The results from these tests have been found to be as accurate as tests performed using a standard serial simulator. The division of the power systems into different subsystems was done by assigning a processor to each area. There were 13 transputers available, therefore, up to 13 different subsystems could be simulated at the same time. This report has preliminary results for a load-flow analysis using a decomposition principal. The report shows that the decomposition algorithm for load-flow analysis is well suited for parallel processing and provides increases in the speed of execution.

  20. Rapid parallel semantic processing of numbers without awareness.

    PubMed

    Van Opstal, Filip; de Lange, Floris P; Dehaene, Stanislas

    2011-07-01

    In this study, we investigate whether multiple digits can be processed at a semantic level without awareness, either serially or in parallel. In two experiments, we presented participants with two successive sets of four simultaneous Arabic digits. The first set was masked and served as a subliminal prime for the second, visible target set. According to the instructions, participants had to extract from the target set either the mean or the sum of the digits, and to compare it with a reference value. Results showed that participants applied the requested instruction to the entire set of digits that was presented below the threshold of conscious perception, because their magnitudes jointly affected the participant's decision. Indeed, response decision could be accurately modeled as a sigmoid logistic function that pooled together the evidence provided by the four targets and, with lower weights, the four primes. In less than 800ms, participants successfully approximated the addition and mean tasks, although they tended to overweight the large numbers, particularly in the sum task. These findings extend previous observations on ensemble coding by showing that set statistics can be extracted from abstract symbolic stimuli rather than low-level perceptual stimuli, and that an ensemble code can be represented without awareness.

  1. An integrated approach to improving the parallel applications development process

    SciTech Connect

    Rasmussen, Craig E; Watson, Gregory R; Tibbitts, Beth R

    2009-01-01

    The development of parallel applications is becoming increasingly important to a broad range of industries. Traditionally, parallel programming was a niche area that was primarily exploited by scientists trying to model extremely complicated physical phenomenon. It is becoming increasingly clear, however, that continued hardware performance improvements through clock scaling and feature-size reduction are simply not going to be achievable for much longer. The hardware vendor's approach to addressing this issue is to employ parallelism through multi-processor and multi-core technologies. While there is little doubt that this approach produces scaling improvements, there are still many significant hurdles to be overcome before parallelism can be employed as a general replacement to more traditional programming techniques. The Parallel Tools Platform (PTP) Project was created in 2005 in an attempt to provide developers with new tools aimed at addressing some of the parallel development issues. Since then, the introduction of a new generation of peta-scale and multi-core systems has highlighted the need for such a platform. In this paper, we describe some of the challenges facing parallel application developers, present the current state of PTP, and provide a simple case study that demonstrates how PTP can be used to locate a potential deadlock situation in an MPI code.

  2. Introducing data parallelism into climate model post-processing through a parallel version of the NCAR Command Language (NCL)

    NASA Astrophysics Data System (ADS)

    Jacob, R. L.; Xu, X.; Krishna, J.; Tautges, T.

    2011-12-01

    The relationship between the needs of post-processing climate model output and the capability of the available tools has reached a crisis point. The large volume of data currently produced by climate models is overwhelming the current, decades-old analysis workflow. The tools used to implement that workflow are now a bottleneck in the climate science discovery processes. This crisis will only worsen as ultra-high resolution global climate models with horizontal scales of 4 km or smaller, running on leadership computing facilities, begin to produce tens to hundreds of terabytes for a single, hundred-year climate simulation. While climate models have used parallelism for several years, the post-processing tools are still mostly single-threaded applications. We have created a Parallel Climate Analysis Library (ParCAL) which implements many common climate analysis operations in a data-parallel fashion using the Message Passing Interface. ParCAL has in turn been built on sophisticated packages for describing grids in parallel (the Mesh Oriented database (MOAB) and for performing vector operations on arbitrary grids (Intrepid). ParCAL is also using parallel I/O through the PnetCDF library. ParCAL has been used to implement a parallel version of the NCAR Command Language (NCL). ParNCL/ParCAL not only speeds up analysis of large datasets but also allows operations to be performed on native grids, eliminating the need to transform everything to latitude-longitude grids. In most cases, users NCL scripts can run unaltered in parallel using ParNCL.

  3. An Efficient Parallel Algorithm for Multiple Sequence Similarities Calculation Using a Low Complexity Method

    PubMed Central

    Marucci, Evandro A.; Neves, Leandro A.; Valêncio, Carlo R.; Pinto, Alex R.; Cansian, Adriano M.; de Souza, Rogeria C. G.; Shiyou, Yang; Machado, José M.

    2014-01-01

    With the advance of genomic researches, the number of sequences involved in comparative methods has grown immensely. Among them, there are methods for similarities calculation, which are used by many bioinformatics applications. Due the huge amount of data, the union of low complexity methods with the use of parallel computing is becoming desirable. The k-mers counting is a very efficient method with good biological results. In this work, the development of a parallel algorithm for multiple sequence similarities calculation using the k-mers counting method is proposed. Tests show that the algorithm presents a very good scalability and a nearly linear speedup. For 14 nodes was obtained 12x speedup. This algorithm can be used in the parallelization of some multiple sequence alignment tools, such as MAFFT and MUSCLE. PMID:25140318

  4. An efficient parallel algorithm for multiple sequence similarities calculation using a low complexity method.

    PubMed

    Marucci, Evandro A; Zafalon, Geraldo F D; Momente, Julio C; Neves, Leandro A; Valêncio, Carlo R; Pinto, Alex R; Cansian, Adriano M; de Souza, Rogeria C G; Shiyou, Yang; Machado, José M

    2014-01-01

    With the advance of genomic researches, the number of sequences involved in comparative methods has grown immensely. Among them, there are methods for similarities calculation, which are used by many bioinformatics applications. Due the huge amount of data, the union of low complexity methods with the use of parallel computing is becoming desirable. The k-mers counting is a very efficient method with good biological results. In this work, the development of a parallel algorithm for multiple sequence similarities calculation using the k-mers counting method is proposed. Tests show that the algorithm presents a very good scalability and a nearly linear speedup. For 14 nodes was obtained 12x speedup. This algorithm can be used in the parallelization of some multiple sequence alignment tools, such as MAFFT and MUSCLE. PMID:25140318

  5. Efficient parallel linear scaling construction of the density matrix for Born-Oppenheimer molecular dynamics.

    PubMed

    Mniszewski, S M; Cawkwell, M J; Wall, M E; Mohd-Yusof, J; Bock, N; Germann, T C; Niklasson, A M N

    2015-10-13

    We present an algorithm for the calculation of the density matrix that for insulators scales linearly with system size and parallelizes efficiently on multicore, shared memory platforms with small and controllable numerical errors. The algorithm is based on an implementation of the second-order spectral projection (SP2) algorithm [ Niklasson, A. M. N. Phys. Rev. B 2002 , 66 , 155115 ] in sparse matrix algebra with the ELLPACK-R data format. We illustrate the performance of the algorithm within self-consistent tight binding theory by total energy calculations of gas phase poly(ethylene) molecules and periodic liquid water systems containing up to 15,000 atoms on up to 16 CPU cores. We consider algorithm-specific performance aspects, such as local vs nonlocal memory access and the degree of matrix sparsity. Comparisons to sparse matrix algebra implementations using off-the-shelf libraries on multicore CPUs, graphics processing units (GPUs), and the Intel many integrated core (MIC) architecture are also presented. The accuracy and stability of the algorithm are illustrated with long duration Born-Oppenheimer molecular dynamics simulations of 1000 water molecules and a 303 atom Trp cage protein solvated by 2682 water molecules.

  6. Efficient parallel linear scaling construction of the density matrix for Born-Oppenheimer molecular dynamics.

    PubMed

    Mniszewski, S M; Cawkwell, M J; Wall, M E; Mohd-Yusof, J; Bock, N; Germann, T C; Niklasson, A M N

    2015-10-13

    We present an algorithm for the calculation of the density matrix that for insulators scales linearly with system size and parallelizes efficiently on multicore, shared memory platforms with small and controllable numerical errors. The algorithm is based on an implementation of the second-order spectral projection (SP2) algorithm [ Niklasson, A. M. N. Phys. Rev. B 2002 , 66 , 155115 ] in sparse matrix algebra with the ELLPACK-R data format. We illustrate the performance of the algorithm within self-consistent tight binding theory by total energy calculations of gas phase poly(ethylene) molecules and periodic liquid water systems containing up to 15,000 atoms on up to 16 CPU cores. We consider algorithm-specific performance aspects, such as local vs nonlocal memory access and the degree of matrix sparsity. Comparisons to sparse matrix algebra implementations using off-the-shelf libraries on multicore CPUs, graphics processing units (GPUs), and the Intel many integrated core (MIC) architecture are also presented. The accuracy and stability of the algorithm are illustrated with long duration Born-Oppenheimer molecular dynamics simulations of 1000 water molecules and a 303 atom Trp cage protein solvated by 2682 water molecules. PMID:26574255

  7. Parallel-processing with surface plasmons, a new strategy for converting the broad solar spectrum

    NASA Technical Reports Server (NTRS)

    Anderson, L. M.

    1982-01-01

    A new strategy for efficient solar-energy conversion is based on parallel processing with surface plasmons: guided electromagnetic waves supported on thin films of common metals like aluminum or silver. The approach is unique in identifying a broadband carrier with suitable range for energy transport and an inelastic tunneling process which can be used to extract more energy from the more energetic carriers without requiring different materials for each frequency band. The aim is to overcome the fundamental 56-percent loss associated with mismatch between the broad solar spectrum and the monoenergetic conduction electrons used to transport energy in conventional silicon solar cells. This paper presents a qualitative discussion of the unknowns and barrier problems, including ideas for coupling surface plasmons into the tunnels, a step which has been the weak link in the efficiency chain.

  8. Parallel processing for nonlinear dynamics simulations of structures including rotating bladed-disk assemblies

    NASA Technical Reports Server (NTRS)

    Hsieh, Shang-Hsien

    1993-01-01

    The principal objective of this research is to develop, test, and implement coarse-grained, parallel-processing strategies for nonlinear dynamic simulations of practical structural problems. There are contributions to four main areas: finite element modeling and analysis of rotational dynamics, numerical algorithms for parallel nonlinear solutions, automatic partitioning techniques to effect load-balancing among processors, and an integrated parallel analysis system.

  9. Parallelized CCHE2D flow model with CUDA Fortran on Graphics Process Units

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper presents the CCHE2D implicit flow model parallelized using CUDA Fortran programming technique on Graphics Processing Units (GPUs). A parallelized implicit Alternating Direction Implicit (ADI) solver using Parallel Cyclic Reduction (PCR) algorithm on GPU is developed and tested. This solve...

  10. Parallel processing of general and specific threat during early stages of perception.

    PubMed

    You, Yuqi; Li, Wen

    2016-03-01

    Differential processing of threat can consummate as early as 100 ms post-stimulus. Moreover, early perception not only differentiates threat from non-threat stimuli but also distinguishes among discrete threat subtypes (e.g. fear, disgust and anger). Combining spatial-frequency-filtered images of fear, disgust and neutral scenes with high-density event-related potentials and intracranial source estimation, we investigated the neural underpinnings of general and specific threat processing in early stages of perception. Conveyed in low spatial frequencies, fear and disgust images evoked convergent visual responses with similarly enhanced N1 potentials and dorsal visual (middle temporal gyrus) cortical activity (relative to neutral cues; peaking at 156 ms). Nevertheless, conveyed in high spatial frequencies, fear and disgust elicited divergent visual responses, with fear enhancing and disgust suppressing P1 potentials and ventral visual (occipital fusiform) cortical activity (peaking at 121 ms). Therefore, general and specific threat processing operates in parallel in early perception, with the ventral visual pathway engaged in specific processing of discrete threats and the dorsal visual pathway in general threat processing. Furthermore, selectively tuned to distinctive spatial-frequency channels and visual pathways, these parallel processes underpin dimensional and categorical threat characterization, promoting efficient threat response. These findings thus lend support to hybrid models of emotion.

  11. A Pervasive Parallel Processing Framework for Data Visualization and Analysis at Extreme Scale

    SciTech Connect

    Moreland, Kenneth; Geveci, Berk

    2014-11-01

    The evolution of the computing world from teraflop to petaflop has been relatively effortless, with several of the existing programming models scaling effectively to the petascale. The migration to exascale, however, poses considerable challenges. All industry trends infer that the exascale machine will be built using processors containing hundreds to thousands of cores per chip. It can be inferred that efficient concurrency on exascale machines requires a massive amount of concurrent threads, each performing many operations on a localized piece of data. Currently, visualization libraries and applications are based off what is known as the visualization pipeline. In the pipeline model, algorithms are encapsulated as filters with inputs and outputs. These filters are connected by setting the output of one component to the input of another. Parallelism in the visualization pipeline is achieved by replicating the pipeline for each processing thread. This works well for today’s distributed memory parallel computers but cannot be sustained when operating on processors with thousands of cores. Our project investigates a new visualization framework designed to exhibit the pervasive parallelism necessary for extreme scale machines. Our framework achieves this by defining algorithms in terms of worklets, which are localized stateless operations. Worklets are atomic operations that execute when invoked unlike filters, which execute when a pipeline request occurs. The worklet design allows execution on a massive amount of lightweight threads with minimal overhead. Only with such fine-grained parallelism can we hope to fill the billions of threads we expect will be necessary for efficient computation on an exascale machine.

  12. Parallel processing architecture for computing inverse differential kinematic equations of the PUMA arm

    NASA Technical Reports Server (NTRS)

    Hsia, T. C.; Lu, G. Z.; Han, W. H.

    1987-01-01

    In advanced robot control problems, on-line computation of inverse Jacobian solution is frequently required. Parallel processing architecture is an effective way to reduce computation time. A parallel processing architecture is developed for the inverse Jacobian (inverse differential kinematic equation) of the PUMA arm. The proposed pipeline/parallel algorithm can be inplemented on an IC chip using systolic linear arrays. This implementation requires 27 processing cells and 25 time units. Computation time is thus significantly reduced.

  13. Endpoint-based parallel data processing with non-blocking collective instructions in a parallel active messaging interface of a parallel computer

    DOEpatents

    Archer, Charles J; Blocksome, Michael A; Cernohous, Bob R; Ratterman, Joseph D; Smith, Brian E

    2014-11-11

    Endpoint-based parallel data processing with non-blocking collective instructions in a PAMI of a parallel computer is disclosed. The PAMI is composed of data communications endpoints, each including a specification of data communications parameters for a thread of execution on a compute node, including specifications of a client, a context, and a task. The compute nodes are coupled for data communications through the PAMI. The parallel application establishes a data communications geometry specifying a set of endpoints that are used in collective operations of the PAMI by associating with the geometry a list of collective algorithms valid for use with the endpoints of the geometry; registering in each endpoint in the geometry a dispatch callback function for a collective operation; and executing without blocking, through a single one of the endpoints in the geometry, an instruction for the collective operation.

  14. Characteristics-Based Methods for Efficient Parallel Integration of the Atmospheric Dynamical Equations

    NASA Astrophysics Data System (ADS)

    Norman, Matthew Ross

    The social need for realistic atmospheric simulation in weather prediction, climate change attribution, seasonal forecasting, and climate projection is great. To obtain realistic simulations, we need more physical processes included in the model with greater fidelity and finer spatial resolution. Spatial resolution primarily drives the need for computational resources because reducing the model grid spacing by a factor f requires f 4 times more computation (assuming 3-D refinement). This compute power comes from large parallel machines with 10,000s of separate nodes and accelerators such as graphics processing units (GPUs) making efficiency a complicated problem. Efficiency parallel integration algorithms need low internode communication, minimal synchronization, large time steps, and clustered computation. To this end, we propose new characteristics-based methods for the atmospheric dynamical equations with these properties in mind. These schemes are capable of simulating at a large CFL time step in only one stage of computations, needing only one copy of the state variables. They are implemented in a 2-D non-hydrostatic compressible equation set in an x-z (horizontal-vertical) Cartesian plane to simulate buoyancy-driven flows such as rising thermals and internal gravity waves. The schemes are implemented to run on CPU and multi-GPU architectures using Nvidia's CUDA (Compute Unified Device Architecture) language to test relative efficiency. Even with- out memory tuning, the GPU code showed roughly 2.5x (5x) better performance per Watt. With optimization, this could increase by an order of magnitude. The methods can use any spatial interpolant, so two major formulations are proposed and tested. One uses WENO interpolants which are pre-computed, and the other uses standard polynomials and computes them on-the-fly. The advantage of on-the-fly calculations is a significant reduction in the volume of data communicated to and from the GPU's slow global memory. In some

  15. Parallel Processing Creates a Low-Cost Growth Path.

    ERIC Educational Resources Information Center

    Shekhel, Alex; Freeman, Eva

    1987-01-01

    Discusses the advantages of parallel processor computers in terms of expandibility, cost, performance and reliability, and suggests that such computers be used in library automation systems as a cost effective approach to planning for the growth of information services and computer applications. (CLB)

  16. Parallel design of JPEG-LS encoder on graphics processing units

    NASA Astrophysics Data System (ADS)

    Duan, Hao; Fang, Yong; Huang, Bormin

    2012-01-01

    With recent technical advances in graphic processing units (GPUs), GPUs have outperformed CPUs in terms of compute capability and memory bandwidth. Many successful GPU applications to high performance computing have been reported. JPEG-LS is an ISO/IEC standard for lossless image compression which utilizes adaptive context modeling and run-length coding to improve compression ratio. However, adaptive context modeling causes data dependency among adjacent pixels and the run-length coding has to be performed in a sequential way. Hence, using JPEG-LS to compress large-volume hyperspectral image data is quite time-consuming. We implement an efficient parallel JPEG-LS encoder for lossless hyperspectral compression on a NVIDIA GPU using the computer unified device architecture (CUDA) programming technology. We use the block parallel strategy, as well as such CUDA techniques as coalesced global memory access, parallel prefix sum, and asynchronous data transfer. We also show the relation between GPU speedup and AVIRIS block size, as well as the relation between compression ratio and AVIRIS block size. When AVIRIS images are divided into blocks, each with 64×64 pixels, we gain the best GPU performance with 26.3x speedup over its original CPU code.

  17. Thermal efficiency of arc welding processes

    SciTech Connect

    DuPont, J.N.; Marder, A.R.

    1995-12-01

    A study was conducted on the arc and melting efficiency of the plasma arc, gas tungsten arc, gas metal arc, and submerged arc welding processes. The results of this work are extended to develop a quantitative method for estimating weld metal dilution in a companion paper. Arc efficiency was determined as a function of current for each process using A36 steel base metal. Melting efficiency was evaluated with variations in arc power and travel speed during deposition of austenitic stainless steel filler metal onto A36 steel substrates. The arc efficiency did not vary significantly within a given process over the range of currents investigated. A semi-empirical relation was developed for the melting efficiency as a function of net arc power and travel speed, which described the experimental data well. An interaction was observed between the arc and melting efficiency. A low arc efficiency factor limits the power delivered to the substrate which, in turn, limits the maximum travel speed for a given set of conditions. High melting efficiency is favored by high arc powers and travel speeds. As a result, a low arc efficiency can limit the maximum obtainable melting efficiency.

  18. Parallel workload analysis in SMP platform: a new modelling approach to infer the hardware efficiency for remote sensing application

    NASA Astrophysics Data System (ADS)

    Yi, Guo; Kanellou, Eleni; Cardona, L. Andrés; Rius, Antonio; Ferrer, Carles

    2009-05-01

    The remote sensing techniques have put great pressure on real-time waveform post-processing design. Due to the intensive computation and multi-channel waveform integration, the overhead between the processing time and the storage of amount of data prior to downlink issues has lead us to get the solution of task-level parallelism. With the development of IC design and innovation of architecture, embedded system can range from a single microprocessor to a complex multi-processor and even including the embedded operating system (OS) on a chip. Therefore symmetric multiprocessing (SMP) with embedded OS offers an attractive way to expose coarse-grained parallelism application. In this paper we demonstrate a new modeling approach. In order to simplify the system; a workload model is derived from a remote sensing application, which represents the workload characteristic and time degrading factors. The intention is to leverage the task-level parallelism load is evenly to each processor in SMP, with the OS level testing to speculate the bottleneck in hardware level. This parallel workload model which maps to a 6-LEON3 SMP architecture, attains a 2.7x mean speedup over a single-LEON3 baseline; with 3-LEON3 attains a 2.23x mean speedup; with 2- LEON3 attains a 1.78x mean speedup over a single-LEON3 baseline. Due to the involved sharing resources and scheduling of multiple CPUs, the system will have a degrading in processing speed. With this lag we could infer the hardware pipeline efficiency. And afford on the processor-set subsystem and memory subsystem analysis reveal the affects on the system throughput.

  19. Control of automatic processes: A parallel distributed-processing model of the stroop effect. Technical report

    SciTech Connect

    Cohen, J.D.; Dunbar, K.; McClelland, J.L.

    1988-06-16

    A growing body of evidence suggests that traditional views of automaticity are in need of revision. For example, automaticity has often been treated as an all-or-none phenomenon, and traditional theories have held that automatic processes are independent of attention. Yet recent empirial data suggests that automatic processes are continuous, and furthermore are subject to attentional control. In this paper we present a model of attention which addresses these issues. Using a parallel distributed processing framework we propose that the attributes of automaticity depend upon the strength of a process and that strength increases with training. Using the Stroop effect as an example, we show how automatic processes are continuous and emerge gradually with practice. Specifically, we present a computational model of the Stroop task which simulates the time course of processing as well as the effects of learning.

  20. Parallel processing numerical method for confined vortex dynamics and applications

    NASA Astrophysics Data System (ADS)

    Bistrian, Diana Alina

    2013-10-01

    This paper explores a combined analytical and numerical technique to investigate the hydrodynamic instability of confined swirling flows, with application to vortex rope dynamics in a Francis turbine diffuser, in condition of sophisticated boundary constraints. We present a new approach based on the method of orthogonal decomposition in the Hilbert space, implemented with a spectral descriptor scheme in discrete space. A parallel implementation of the numerical scheme is conducted reducing the computational time compared to other techniques.

  1. A Parallel Processing Algorithm for Remote Sensing Classification

    NASA Technical Reports Server (NTRS)

    Gualtieri, J. Anthony

    2005-01-01

    A current thread in parallel computation is the use of cluster computers created by networking a few to thousands of commodity general-purpose workstation-level commuters using the Linux operating system. For example on the Medusa cluster at NASA/GSFC, this provides for super computing performance, 130 G(sub flops) (Linpack Benchmark) at moderate cost, $370K. However, to be useful for scientific computing in the area of Earth science, issues of ease of programming, access to existing scientific libraries, and portability of existing code need to be considered. In this paper, I address these issues in the context of tools for rendering earth science remote sensing data into useful products. In particular, I focus on a problem that can be decomposed into a set of independent tasks, which on a serial computer would be performed sequentially, but with a cluster computer can be performed in parallel, giving an obvious speedup. To make the ideas concrete, I consider the problem of classifying hyperspectral imagery where some ground truth is available to train the classifier. In particular I will use the Support Vector Machine (SVM) approach as applied to hyperspectral imagery. The approach will be to introduce notions about parallel computation and then to restrict the development to the SVM problem. Pseudocode (an outline of the computation) will be described and then details specific to the implementation will be given. Then timing results will be reported to show what speedups are possible using parallel computation. The paper will close with a discussion of the results.

  2. Agarose droplet microfluidics for highly parallel and efficient single molecule emulsion PCR.

    PubMed

    Leng, Xuefei; Zhang, Wenhua; Wang, Chunming; Cui, Liang; Yang, Chaoyong James

    2010-11-01

    An agarose droplet method was developed for highly parallel and efficient single molecule emulsion PCR. The method capitalizes on the unique thermoresponsive sol-gel switching property of agarose for highly efficient DNA amplification and amplicon trapping. Uniform agarose solution droplets generated via a microfluidic chip serve as robust and inert nanolitre PCR reactors for single copy DNA molecule amplification. After PCR, agarose droplets are gelated to form agarose beads, trapping all amplicons in each reactor to maintain the monoclonality of each droplet. This method does not require cocapsulation of primer labeled microbeads, allows high throughput generation of uniform droplets and enables high PCR efficiency, making it a promising platform for many single copy genetic studies.

  3. Parallel processing data network of master and slave transputers controlled by a serial control network

    DOEpatents

    Crosetto, D.B.

    1996-12-31

    The present device provides for a dynamically configurable communication network having a multi-processor parallel processing system having a serial communication network and a high speed parallel communication network. The serial communication network is used to disseminate commands from a master processor to a plurality of slave processors to effect communication protocol, to control transmission of high density data among nodes and to monitor each slave processor`s status. The high speed parallel processing network is used to effect the transmission of high density data among nodes in the parallel processing system. Each node comprises a transputer, a digital signal processor, a parallel transfer controller, and two three-port memory devices. A communication switch within each node connects it to a fast parallel hardware channel through which all high density data arrives or leaves the node. 6 figs.

  4. Parallel processing data network of master and slave transputers controlled by a serial control network

    DOEpatents

    Crosetto, Dario B.

    1996-01-01

    The present device provides for a dynamically configurable communication network having a multi-processor parallel processing system having a serial communication network and a high speed parallel communication network. The serial communication network is used to disseminate commands from a master processor (100) to a plurality of slave processors (200) to effect communication protocol, to control transmission of high density data among nodes and to monitor each slave processor's status. The high speed parallel processing network is used to effect the transmission of high density data among nodes in the parallel processing system. Each node comprises a transputer (104), a digital signal processor (114), a parallel transfer controller (106), and two three-port memory devices. A communication switch (108) within each node (100) connects it to a fast parallel hardware channel (70) through which all high density data arrives or leaves the node.

  5. Parallelizing serial code for a distributed processing environment with an application to high frequency electromagnetic scattering

    NASA Astrophysics Data System (ADS)

    Work, Paul R.

    1991-12-01

    This thesis investigates the parallelization of existing serial programs in computational electromagnetics for use in a parallel environment. Existing algorithms for calculating the radar cross section of an object are covered, and a ray-tracing code is chosen for implementation on a parallel machine. Current parallel architectures are introduced and a suitable parallel machine is selected for the implementation of the chosen ray-tracing algorithm. The standard techniques for the parallelization of serial codes are discussed, including load balancing and decomposition considerations, and appropriate methods for the parallelization effort are selected. A load balancing algorithm is modified to increase the efficiency of the application, and a high level design of the structure of the serial program is presented. A detailed design of the modifications for the parallel implementation is also included, with both the high level and the detailed design specified in a high level design language called UNITY. The correctness of the design is proven using UNITY and standard logic operations. The theoretical and empirical results show that it is possible to achieve an efficient parallel application for a serial computational electromagnetic program where the characteristics of the algorithm and the target architecture critically influence the development of such an implementation.

  6. Toward a Model Framework of Generalized Parallel Componential Processing of Multi-Symbol Numbers

    ERIC Educational Resources Information Center

    Huber, Stefan; Cornelsen, Sonja; Moeller, Korbinian; Nuerk, Hans-Christoph

    2015-01-01

    In this article, we propose and evaluate a new model framework of parallel componential multi-symbol number processing, generalizing the idea of parallel componential processing of multi-digit numbers to the case of negative numbers by considering the polarity signs similar to single digits. In a first step, we evaluated this account by defining…

  7. Studies in optical parallel processing. [All optical and electro-optic approaches

    NASA Technical Reports Server (NTRS)

    Lee, S. H.

    1978-01-01

    Threshold and A/D devices for converting a gray scale image into a binary one were investigated for all-optical and opto-electronic approaches to parallel processing. Integrated optical logic circuits (IOC) and optical parallel logic devices (OPA) were studied as an approach to processing optical binary signals. In the IOC logic scheme, a single row of an optical image is coupled into the IOC substrate at a time through an array of optical fibers. Parallel processing is carried out out, on each image element of these rows, in the IOC substrate and the resulting output exits via a second array of optical fibers. The OPAL system for parallel processing which uses a Fabry-Perot interferometer for image thresholding and analog-to-digital conversion, achieves a higher degree of parallel processing than is possible with IOC.

  8. Parallel damage in mitochondrial and lysosomal compartments promotes efficient cell death with autophagy: The case of the pentacyclic triterpenoids

    PubMed Central

    Martins, Waleska K.; Costa, Érico T.; Cruz, Mário C.; Stolf, Beatriz S.; Miotto, Ronei; Cordeiro, Rodrigo M.; Baptista, Maurício S.

    2015-01-01

    The role of autophagy in cell death is still controversial and a lot of debate has concerned the transition from its pro-survival to its pro-death roles. The similar structure of the triterpenoids Betulinic (BA) and Oleanolic (OA) acids allowed us to prove that this transition involves parallel damage in mitochondria and lysosome. After treating immortalized human skin keratinocytes (HaCaT) with either BA or OA, we evaluated cell viability, proliferation and mechanism of cell death, function and morphology of mitochondria and lysosomes, and the status of the autophagy flux. We also quantified the interactions of BA and OA with membrane mimics, both in-vitro and in-silico. Essentially, OA caused mitochondrial damage that relied on autophagy to rescue cellular homeostasis, which failed upon lysosomal inhibition by Chloroquine or Bafilomycin-A1. BA caused parallel damage on mitochondria and lysosome, turning autophagy into a destructive process. The higher cytotoxicity of BA correlated with its stronger efficiency in damaging membrane mimics. Based on these findings, we underlined the concept that autophagy will turn into a destructive outcome when there is parallel damage in mitochondrial and lysosomal membranes. We trust that this concept will help the development of new drugs against aggressive cancers. PMID:26213355

  9. Two-dimensional mesh-connected parallel processor with complex processing elements

    NASA Astrophysics Data System (ADS)

    Chen, Chaoyang; Shen, Xubang; Wang, Zhong; Sang, Hongshi

    2001-09-01

    LS MPP is a massively parallel processor .It has fine-grained parallelism with up to 4096 processing elements arranged in a SIMD architecture .The processing elements are arranged in 64x64 two-dimensional mesh-connected array for low-level image processing .In this paper, the system architecture ,the components of processing element ,array controller ,memory organization of LS MPP processor are described .In the final ,we have discussed the performance of LS MPP.

  10. Efficient Parallel Global Optimization for High Resolution Hydrologic and Climate Impact Models

    NASA Astrophysics Data System (ADS)

    Shoemaker, C. A.; Mueller, J.; Pang, M.

    2013-12-01

    High Resolution hydrologic models are typically computationally expensive, requiring many minutes or perhaps hours for one simulation. Optimization can be used with these models for parameter estimation or for analyzing management alternatives. However Optimization of these computationally expensive simulations requires algorithms that can obtain accurate answers with relatively few simulations to avoid infeasibly long computation times. We have developed a number of efficient parallel algorithms and software codes for optimization of expensive problems with multiple local minimum. This is open source software we are distributing. It runs in Matlab and Python, and has been run on Yellowstone supercomputer. The talk will quickly discuss the characteristics of the problem (e.g. the presence of integer as well as continuous variables, the number of dimensions, the availability of parallel/grid computing, the number of simulations that can be allowed to find a solution, etc. ) that determine which algorithms are most appropriate for each type of problem. A major application of this optimization software is for parameter estimation for nonlinear hydrologic models, including contaminant transport in subsurface (e.g. for groundwater remediation or multi-phase flow for carbon sequestration), nutrient transport in watersheds, and climate models. We will present results for carbon sequestration plume monitoring (multi-phase, multi-constiuent), for groundwater remediation, and for the CLM climate model. The carbon sequestration example is based on the Frio CO2 field site and the groundwater example is for a 50,000 acre remediation site (with model requiring about 1 hour per simulation). Parallel speed-ups are excellent in most cases, and our serial and parallel algorithms tend to outperform alternative methods on complex computationally expensive simulations that have multiple global minima.

  11. Increasing Efficiency: A Process-Oriented Approach.

    ERIC Educational Resources Information Center

    Harbour, Jerry L.

    1993-01-01

    Discussion of the need to increase efficiency focuses on a process-oriented approach for systematically identifying and minimizing non-value-adding process steps to analyze and improve tasks, services, and production. Highlights include a historical perspective, a discussion of wasted efforts, and a case study. (Contains 16 references.) (LRW)

  12. Eco-Efficiency Analysis of biotechnological processes.

    PubMed

    Saling, Peter

    2005-07-01

    Eco-Efficiency has been variously defined and analytically implemented by several workers. In most cases, Eco-Efficiency is taken to mean the ecological optimization of overall systems while not disregarding economic factors. Eco-Efficiency should increase the positive ecological performance of a commercial company in relation to economic value creation--or to reduce negative effects. Several companies use Eco-Efficiency Analysis for decision-making processes; and industrial examples of best practices in developing and implementing Eco-Efficiency have been reviewed. They clearly demonstrate the environmental and business benefits of Eco-Efficiency. An instrument for the early recognition and systematic detection of economic and environmental opportunities and risks for production processes in the chemical industry began use in 1997, since when different new features have been developed, leading to many examples. This powerful Eco-Efficiency Analysis allows a feasibility evaluation of existing and future business activities and is applied by BASF. In many cases, decision-makers are able to choose among alternative processes for making a product.

  13. Representing S-expressions for the efficient evaluation of Lisp on parallel processors

    SciTech Connect

    Harrison, W.L. III; Padua, D.A.

    1986-03-01

    Present methods for exploiting parallelism in Lisp programs perform poorly upon lists (long, flat s-expressions), as such structures must be both created and traversed sequentially. While such a serial operation may be masked by overlapping it with other computation (by virtue of process spawning, or by the use of a mechanism such as futures), it represents a lost (and potentially large) source of parallelism. In this paper we describe the representation of s-expressions employed in PARCEL (Project for the Automatic Restructuring and Concurrent Evaluation of Lisp), which facilitates the creation and access of lists, without compromising the performance of functions which manipulate s-expressions of a more general shape. Using this representation, the PARCEL compiler translates Lisp programs written in a subset of the Scheme dialect (which allows for global variables and atom properties) into code for a large, tightly coupled shared memory multiprocessor. 12 refs.

  14. Diagrammatic many-body perturbation expansion for atoms and molecules: VI Experiments in vector processing and parallel processing for second-order energy calculations

    NASA Astrophysics Data System (ADS)

    Moncrieff, David; Baker, David J.; Wilson, Stephen

    1989-08-01

    The efficient evaluation of the second-order expression in the many-body perturbation theory expansion for the correlation energy on vector processing and parallel processing computers is discussed. It is argued that the linked diagram theorem not only leads to the well known theoretical advantages of the many-body perturbation theory approach which allows the calculation of correlation energies for large (i.e. extended molecules or species containing heavy atoms) systems but also decouples the many-electron problem allowing efficient implementation on parallel processing machines. Furthermore, the computation associated with each of the resulting subproblems is very well suited to vector processing machines. Timing tests are reported for the CRAY 1 and CDC Cyber 205 vector processors, for a 1 processor implementation on the CRAY X-MP/48 and the ETA-10E, and for a 4 processor implementation on the Cray X-MP/48.

  15. Signal processing applications of massively parallel charge domain computing devices

    NASA Technical Reports Server (NTRS)

    Fijany, Amir (Inventor); Barhen, Jacob (Inventor); Toomarian, Nikzad (Inventor)

    1999-01-01

    The present invention is embodied in a charge coupled device (CCD)/charge injection device (CID) architecture capable of performing a Fourier transform by simultaneous matrix vector multiplication (MVM) operations in respective plural CCD/CID arrays in parallel in O(1) steps. For example, in one embodiment, a first CCD/CID array stores charge packets representing a first matrix operator based upon permutations of a Hartley transform and computes the Fourier transform of an incoming vector. A second CCD/CID array stores charge packets representing a second matrix operator based upon different permutations of a Hartley transform and computes the Fourier transform of an incoming vector. The incoming vector is applied to the inputs of the two CCD/CID arrays simultaneously, and the real and imaginary parts of the Fourier transform are produced simultaneously in the time required to perform a single MVM operation in a CCD/CID array.

  16. Parallel workflow tools to facilitate human brain MRI post-processing

    PubMed Central

    Cui, Zaixu; Zhao, Chenxi; Gong, Gaolang

    2015-01-01

    Multi-modal magnetic resonance imaging (MRI) techniques are widely applied in human brain studies. To obtain specific brain measures of interest from MRI datasets, a number of complex image post-processing steps are typically required. Parallel workflow tools have recently been developed, concatenating individual processing steps and enabling fully automated processing of raw MRI data to obtain the final results. These workflow tools are also designed to make optimal use of available computational resources and to support the parallel processing of different subjects or of independent processing steps for a single subject. Automated, parallel MRI post-processing tools can greatly facilitate relevant brain investigations and are being increasingly applied. In this review, we briefly summarize these parallel workflow tools and discuss relevant issues. PMID:26029043

  17. Parallel processing of remotely sensed data: Application to the ATSR-2 instrument

    NASA Astrophysics Data System (ADS)

    Simpson, J.; McIntire, T.; Berg, J.; Tsou, Y.

    2007-01-01

    Massively parallel computational paradigms can mitigate many issues associated with the analysis of large and complex remotely sensed data sets. Recently, the Beowulf cluster has emerged as the most attractive, massively parallel architecture due to its low cost and high performance. Whereas most Beowulf designs have emphasized numerical modeling applications, the Parallel Image Processing Environment (PIPE) specifically addresses the unique requirements of remote sensing applications. Automated, parallelization of user-defined analyses is fully supported. A neural network application, applied to Along Track Scanning Radiometer-2 (ATSR-2) data shows the advantages and performance characteristics of PIPE.

  18. Creation of the BMA ensemble for SST using a parallel processing technique

    NASA Astrophysics Data System (ADS)

    Kim, Kwangjin; Lee, Yang Won

    2013-10-01

    Despite the same purpose, each satellite product has different value because of its inescapable uncertainty. Also the satellite products have been calculated for a long time, and the kinds of the products are various and enormous. So the efforts for reducing the uncertainty and dealing with enormous data will be necessary. In this paper, we create an ensemble Sea Surface Temperature (SST) using MODIS Aqua, MODIS Terra and COMS (Communication Ocean and Meteorological Satellite). We used Bayesian Model Averaging (BMA) as ensemble method. The principle of the BMA is synthesizing the conditional probability density function (PDF) using posterior probability as weight. The posterior probability is estimated using EM algorithm. The BMA PDF is obtained by weighted average. As the result, the ensemble SST showed the lowest RMSE and MAE, which proves the applicability of BMA for satellite data ensemble. As future work, parallel processing techniques using Hadoop framework will be adopted for more efficient computation of very big satellite data.

  19. Arts Integration Parallels Between Music and Reading: Process, Product and Affective Response.

    ERIC Educational Resources Information Center

    Merrion, Margaret Dee

    The process of aesthetic education is not limited to the fine arts. Parallels may be identified in the language arts and particularly in the art of creative reading. As in a musical experience, a creative reader will apprehend the content of the literature and couple personal feelings with the events of the reading experience. Parallel brain…

  20. Correlated activity supports efficient cortical processing

    PubMed Central

    Hung, Chou P.; Cui, Ding; Chen, Yueh-peng; Lin, Chia-pei; Levine, Matthew R.

    2015-01-01

    Visual recognition is a computational challenge that is thought to occur via efficient coding. An important concept is sparseness, a measure of coding efficiency. The prevailing view is that sparseness supports efficiency by minimizing redundancy and correlations in spiking populations. Yet, we recently reported that “choristers”, neurons that behave more similarly (have correlated stimulus preferences and spontaneous coincident spiking), carry more generalizable object information than uncorrelated neurons (“soloists”) in macaque inferior temporal (IT) cortex. The rarity of choristers (as low as 6% of IT neurons) indicates that they were likely missed in previous studies. Here, we report that correlation strength is distinct from sparseness (choristers are not simply broadly tuned neurons), that choristers are located in non-granular output layers, and that correlated activity predicts human visual search efficiency. These counterintuitive results suggest that a redundant correlational structure supports efficient processing and behavior. PMID:25610392

  1. Efficient time-dependent density functional theory approximations for hybrid density functionals: Analytical gradients and parallelization

    NASA Astrophysics Data System (ADS)

    Petrenko, Taras; Kossmann, Simone; Neese, Frank

    2011-02-01

    In this paper, we present the implementation of efficient approximations to time-dependent density functional theory (TDDFT) within the Tamm-Dancoff approximation (TDA) for hybrid density functionals. For the calculation of the TDDFT/TDA excitation energies and analytical gradients, we combine the resolution of identity (RI-J) algorithm for the computation of the Coulomb terms and the recently introduced "chain of spheres exchange" (COSX) algorithm for the calculation of the exchange terms. It is shown that for extended basis sets, the RIJCOSX approximation leads to speedups of up to 2 orders of magnitude compared to traditional methods, as demonstrated for hydrocarbon chains. The accuracy of the adiabatic transition energies, excited state structures, and vibrational frequencies is assessed on a set of 27 excited states for 25 molecules with the configuration interaction singles and hybrid TDDFT/TDA methods using various basis sets. Compared to the canonical values, the typical error in transition energies is of the order of 0.01 eV. Similar to the ground-state results, excited state equilibrium geometries differ by less than 0.3 pm in the bond distances and 0.5° in the bond angles from the canonical values. The typical error in the calculated excited state normal coordinate displacements is of the order of 0.01, and relative error in the calculated excited state vibrational frequencies is less than 1%. The errors introduced by the RIJCOSX approximation are, thus, insignificant compared to the errors related to the approximate nature of the TDDFT methods and basis set truncation. For TDDFT/TDA energy and gradient calculations on Ag-TB2-helicate (156 atoms, 2732 basis functions), it is demonstrated that the COSX algorithm parallelizes almost perfectly (speedup ˜26-29 for 30 processors). The exchange-correlation terms also parallelize well (speedup ˜27-29 for 30 processors). The solution of the Z-vector equations shows a speedup of ˜24 on 30 processors. The

  2. Parallel processing a real code: A case history

    SciTech Connect

    Mandell, D.A.; Trease, H.E.

    1988-01-01

    A three-dimensional, time-dependent Free-Lagrange hydrodynamics code has been multitasked and autotasked on a Cray X-MP/416. The multitasking was done by using the Los Alamos Multitasking Control Library, which is a superset of the Cray multitasking library. Autotasking is done by using constructs which are only comment cards if the source code is not run through a preprocessor. The 3-D algorithm has presented a number of problems that simpler algorithms, such as 1-D hydrodynamics, did not exhibit. Problems in converting the serial code, originally written for a Cray 1, to a multitasking code are discussed, Autotasking of a rewritten version of the code is discussed. Timing results for subroutines and hot spots in the serial code are presented and suggestions for additional tools and debugging aids are given. Theoretical speedup results obtained from Amdahl's law and actual speedup results obtained on a dedicated machine are presented. Suggestions for designing large parallel codes are given. 8 refs., 13 figs.

  3. Parallel processing a three-dimensional free-lagrange code

    SciTech Connect

    Mandell, D.A.; Trease, H.E. )

    1989-01-01

    A three-dimensional, time-dependent free-Lagrange hydrodynamics code has been multitasked and autotasked on a CRAY X-MP/416. The multitasking was done by using the Los Alamos Multitasking Control Library, which is a superset of the CRAY multitasking library. Autotasking is done by using constructs which are only comment cards if the source code is not run through a preprocessor. The three-dimensional algorithm has presented a number of problems that simpler algorithms, such as those for one-dimensional hydrodynamics, did not exhibit. Problems in converting the serial code, originally written for a CRAY-1, to a multitasking code are discussed. Autotasking of a rewritten version of the code is discussed. Timing results for subroutines and hot spots in the serial code are presented and suggestions for additional tools and debugging aids are given. Theoretical speedup results obtained from Amdahl's law and actual speedup results obtained on a dedicated machine are presented. Suggestions for designing large parallel codes are given.

  4. Parallel Block Structured Adaptive Mesh Refinement on Graphics Processing Units

    SciTech Connect

    Beckingsale, D. A.; Gaudin, W. P.; Hornung, R. D.; Gunney, B. T.; Gamblin, T.; Herdman, J. A.; Jarvis, S. A.

    2014-11-17

    Block-structured adaptive mesh refinement is a technique that can be used when solving partial differential equations to reduce the number of zones necessary to achieve the required accuracy in areas of interest. These areas (shock fronts, material interfaces, etc.) are recursively covered with finer mesh patches that are grouped into a hierarchy of refinement levels. Despite the potential for large savings in computational requirements and memory usage without a corresponding reduction in accuracy, AMR adds overhead in managing the mesh hierarchy, adding complex communication and data movement requirements to a simulation. In this paper, we describe the design and implementation of a native GPU-based AMR library, including: the classes used to manage data on a mesh patch, the routines used for transferring data between GPUs on different nodes, and the data-parallel operators developed to coarsen and refine mesh data. We validate the performance and accuracy of our implementation using three test problems and two architectures: an eight-node cluster, and over four thousand nodes of Oak Ridge National Laboratory’s Titan supercomputer. Our GPU-based AMR hydrodynamics code performs up to 4.87× faster than the CPU-based implementation, and has been scaled to over four thousand GPUs using a combination of MPI and CUDA.

  5. Advantages of Parallel Processing and the Effects of Communications Time

    NASA Technical Reports Server (NTRS)

    Eddy, Wesley M.; Allman, Mark

    2000-01-01

    Many computing tasks involve heavy mathematical calculations, or analyzing large amounts of data. These operations can take a long time to complete using only one computer. Networks such as the Internet provide many computers with the ability to communicate with each other. Parallel or distributed computing takes advantage of these networked computers by arranging them to work together on a problem, thereby reducing the time needed to obtain the solution. The drawback to using a network of computers to solve a problem is the time wasted in communicating between the various hosts. The application of distributed computing techniques to a space environment or to use over a satellite network would therefore be limited by the amount of time needed to send data across the network, which would typically take much longer than on a terrestrial network. This experiment shows how much faster a large job can be performed by adding more computers to the task, what role communications time plays in the total execution time, and the impact a long-delay network has on a distributed computing system.

  6. Neural processes in symmetry perception: a parallel spatio-temporal model.

    PubMed

    Zhu, Tao

    2014-04-01

    Symmetry is usually computationally expensive to detect reliably, while it is relatively easy to perceive. In spite of many attempts to understand the neurofunctional properties of symmetry processing, no symmetry-specific activation was found in earlier cortical areas. Psychophysical evidence relating to the processing mechanisms suggests that the basic processes of symmetry perception would not perform a serial, point-by-point comparison of structural features but rather operate in parallel. Here, modeling of neural processes in psychophysical detection of bilateral texture symmetry is considered. A simple fine-grained algorithm that is capable of performing symmetry estimation without explicit comparison of remote elements is introduced. A computational model of symmetry perception is then described to characterize the underlying mechanisms as one-dimensional spatio-temporal neural processes, each of which is mediated by intracellular horizontal connections in primary visual cortex and adopts the proposed algorithm for the neural computation. Simulated experiments have been performed to show the efficiency and the dynamics of the model. Model and human performances are comparable for symmetry perception of intensity images. Interestingly, the responses of V1 neurons to propagation activities reflecting higher-order perceptual computations have been reported in neurophysiologic experiments.

  7. Integration of optoelectronic technologies for chip-to- chip interconnections and parallel pipeline processing

    NASA Astrophysics Data System (ADS)

    Wu, Jenming

    Digital information services such as multimedia systems and data communications require the processing and transfer of tremendous amount of data. These data need to be stored, accessed and delivered efficiently and reliably at high speed for various user applications. This represents a great challenge for current electronic systems. Electronics is effective in providing high performance processing and computation, but its input/outputs (I/Os) bandwidth is unable to scale with its processing power. The signal I/Os or interconnections are needed between processors and input devices, between processors for multiprocessor systems, and between processors and storage devices. Novel chip-to-chip interconnect technologies are needed to meet this challenge. This work integrates optoelectronic technologies for chip-to-chip interconnects and parallel pipeline processing. Photonic and electronic technologies are complementary to each other in the sense that electronics is more suitable for high-speed, low cost computation, and photonics is more suitable for high-bandwidth information transmission. Smart pixel technology uses electronics for logic switching and optics for chip-to- chip interconnects, thus combining the abilities of photonics and electronics nicely. This work describes both vertical and horizontal integration of smart pixel technologies for chip-to-chip optical interconnects and its applications. We present smart pixel VLSI designs in both hybrid CMOS/MQW smart pixel and monolithic GaAs smart pixel technologies. We use the CMOS/MQW technology for smart pixel array cellular logic (SPARCL) processors for SIMD parallel pipeline processing. We have tested the chip and constructed a prototype system for device characterization and system demonstration. We have verified the functionality of the system and characterized the electrical functions of the chip and the optoelectronic properties of the MQW devices. We have developed algorithms that utilize SPARCL for various

  8. Control of automatic processes: A parallel distributed-processing account of the Stroop effect. Technical report

    SciTech Connect

    Cohen, J.D.; Dunbar, K.; McClelland, J.L.

    1989-11-22

    A growing body of evidence suggests that traditional views of automaticity are in need of revision. For example, automaticity has often been treated as an all-or-none phenomenon, and traditional theories have held that automatic processes are independent of attention. Yet recent empirical data suggest that automatic processes are continuous, and furthermore are subject to attentional control. In this paper we present a model of attention which addresses these issues. Using a parallel distributed processing framework we propose that the attributes of automaticity depend upon the strength of a processing pathway and that strength increases with training. Using the Stroop effect as an example, we show how automatic processes are continuous and emerge gradually with practice. Specifically, we present a computational model of the Stroop task which simulates the time course of processing as well as the effects of learning. This was accomplished by combining the cascade mechanism described by McClelland (1979) with the back propagation learning algorithm (Rumelhart, Hinton, Williams, 1986). The model is able to simulate performance in the standard Stroop task, as well as aspects of performance in variants of this task which manipulate SOA, response set, and degree of practice. In the discussion we contrast our model with other models, and indicate how it relates to many of the central issues in the literature on attention, automaticity, and interference.

  9. An iterative expanding and shrinking process for processor allocation in mixed-parallel workflow scheduling.

    PubMed

    Huang, Kuo-Chan; Wu, Wei-Ya; Wang, Feng-Jian; Liu, Hsiao-Ching; Hung, Chun-Hao

    2016-01-01

    Parallel computation has been widely applied in a variety of large-scale scientific and engineering applications. Many studies indicate that exploiting both task and data parallelisms, i.e. mixed-parallel workflows, to solve large computational problems can get better efficacy compared with either pure task parallelism or pure data parallelism. Scheduling traditional workflows of pure task parallelism on parallel systems has long been known to be an NP-complete problem. Mixed-parallel workflow scheduling has to deal with an additional challenging issue of processor allocation. In this paper, we explore the processor allocation issue in scheduling mixed-parallel workflows of moldable tasks, called M-task, and propose an Iterative Allocation Expanding and Shrinking (IAES) approach. Compared to previous approaches, our IAES has two distinguishing features. The first is allocating more processors to the tasks on allocated critical paths for effectively reducing the makespan of workflow execution. The second is allowing the processor allocation of an M-task to shrink during the iterative procedure, resulting in a more flexible and effective process for finding better allocation. The proposed IAES approach has been evaluated with a series of simulation experiments and compared to several well-known previous methods, including CPR, CPA, MCPA, and MCPA2. The experimental results indicate that our IAES approach outperforms those previous methods significantly in most situations, especially when nodes of the same layer in a workflow might have unequal workloads. PMID:27504236

  10. An iterative expanding and shrinking process for processor allocation in mixed-parallel workflow scheduling.

    PubMed

    Huang, Kuo-Chan; Wu, Wei-Ya; Wang, Feng-Jian; Liu, Hsiao-Ching; Hung, Chun-Hao

    2016-01-01

    Parallel computation has been widely applied in a variety of large-scale scientific and engineering applications. Many studies indicate that exploiting both task and data parallelisms, i.e. mixed-parallel workflows, to solve large computational problems can get better efficacy compared with either pure task parallelism or pure data parallelism. Scheduling traditional workflows of pure task parallelism on parallel systems has long been known to be an NP-complete problem. Mixed-parallel workflow scheduling has to deal with an additional challenging issue of processor allocation. In this paper, we explore the processor allocation issue in scheduling mixed-parallel workflows of moldable tasks, called M-task, and propose an Iterative Allocation Expanding and Shrinking (IAES) approach. Compared to previous approaches, our IAES has two distinguishing features. The first is allocating more processors to the tasks on allocated critical paths for effectively reducing the makespan of workflow execution. The second is allowing the processor allocation of an M-task to shrink during the iterative procedure, resulting in a more flexible and effective process for finding better allocation. The proposed IAES approach has been evaluated with a series of simulation experiments and compared to several well-known previous methods, including CPR, CPA, MCPA, and MCPA2. The experimental results indicate that our IAES approach outperforms those previous methods significantly in most situations, especially when nodes of the same layer in a workflow might have unequal workloads.

  11. Parallel plan execution with self-processing networks

    NASA Technical Reports Server (NTRS)

    Dautrechy, C. Lynne; Reggia, James A.

    1989-01-01

    A critical issue for space operations is how to develop and apply advanced automation techniques to reduce the cost and complexity of working in space. In this context, it is important to examine how recent advances in self-processing networks can be applied for planning and scheduling tasks. For this reason, the feasibility of applying self-processing network models to a variety of planning and control problems relevant to spacecraft activities is being explored. Goals are to demonstrate that self-processing methods are applicable to these problems, and that MIRRORS/II, a general purpose software environment for implementing self-processing models, is sufficiently robust to support development of a wide range of application prototypes. Using MIRRORS/II and marker passing modelling techniques, a model of the execution of a Spaceworld plan was implemented. This is a simplified model of the Voyager spacecraft which photographed Jupiter, Saturn, and their satellites. It is shown that plan execution, a task usually solved using traditional artificial intelligence (AI) techniques, can be accomplished using a self-processing network. The fact that self-processing networks were applied to other space-related tasks, in addition to the one discussed here, demonstrates the general applicability of this approach to planning and control problems relevant to spacecraft activities. It is also demonstrated that MIRRORS/II is a powerful environment for the development and evaluation of self-processing systems.

  12. Quality and efficiency successes leveraging IT and new processes.

    PubMed

    Chaiken, Barry P; Christian, Charles E; Johnson, Liz

    2007-01-01

    Today, healthcare annually invests billions of dollars in information technology, including clinical systems, electronic medical records and interoperability platforms. While continued investment and parallel development of standards are critical to secure exponential benefits from clinical information technology, intelligent and creative redesign of processes through path innovation is necessary to deliver meaningful value. Reports from two organizations included in this report review the steps taken to reinvent clinical processes that best leverage information technology to deliver safer and more efficient care. Good Samaritan Hospital, Vincennes, Indiana, implemented electronic charting, point-of-care bar coding of medications prior to administration, and integrated clinical documentation for nursing, laboratory, radiology and pharmacy. Tenet Healthcare, during its implementation and deployment of multiple clinical systems across several hospitals, focused on planning that included team-based process redesign. In addition, Tenet constructed valuable and measurable metrics that link outcomes with its strategic goals.

  13. Parallel and series FED microstrip array with high efficiency and low cross polarization

    NASA Technical Reports Server (NTRS)

    Huang, John (Inventor)

    1995-01-01

    A microstrip array antenna for vertically polarized fan beam (approximately 2 deg x 50 deg) for C-band SAR applications with a physical area of 1.7 m by 0.17 m comprises two rows of patch elements and employs a parallel feed to left- and right-half sections of the rows. Each section is divided into two segments that are fed in parallel with the elements in each segment fed in series through matched transmission lines for high efficiency. The inboard section has half the number of patch elements of the outboard section, and the outboard sections, which have tapered distribution with identical transmission line sections, terminated with half wavelength long open-circuit stubs so that the remaining energy is reflected and radiated in phase. The elements of the two inboard segments of the two left- and right-half sections are provided with tapered transmission lines from element to element for uniform power distribution over the central third of the entire array antenna. The two rows of array elements are excited at opposite patch feed locations with opposite (180 deg difference) phases for reduced cross-polarization.

  14. Algorithmic Processes for Increasing Design Efficiency.

    ERIC Educational Resources Information Center

    Terrell, William R.

    1983-01-01

    Discusses the role of algorithmic processes as a supplementary method for producing cost-effective and efficient instructional materials. Examines three approaches to problem solving in the context of developing training materials for the Naval Training Command: application of algorithms, quasi-algorithms, and heuristics. (EAO)

  15. Efficient Serial and Parallel Algorithms for Selection of Unique Oligos in EST Databases

    PubMed Central

    Mata-Montero, Manrique; Shalaby, Nabil; Sheppard, Bradley

    2013-01-01

    Obtaining unique oligos from an EST database is a problem of great importance in bioinformatics, particularly in the discovery of new genes and the mapping of the human genome. Many algorithms have been developed to find unique oligos, many of which are much less time consuming than the traditional brute force approach. An algorithm was presented by Zheng et al. (2004) which finds the solution of the unique oligos search problem efficiently. We implement this algorithm as well as several new algorithms based on some theorems included in this paper. We demonstrate how, with these new algorithms, we can obtain unique oligos much faster than with previous ones. We parallelize these new algorithms to further improve the time of finding unique oligos. All algorithms are run on ESTs obtained from a Barley EST database. PMID:23653640

  16. Performance of a VME-based parallel processing LIDAR data acquisition system (summary)

    SciTech Connect

    Moore, K.; Buttler, B.; Caffrey, M.; Soriano, C.

    1995-05-01

    It may be possible to make accurate real time, autonomous, 2 and 3 dimensional wind measurements remotely with an elastic backscatter Light Detection and Ranging (LIDAR) system by incorporating digital parallel processing hardware into the data acquisition system. In this paper, we report the performance of a commercially available digital parallel processing system in implementing the maximum correlation technique for wind sensing using actual LIDAR data. Timing and numerical accuracy are benchmarked against a standard microprocessor impementation.

  17. The generic simulation cell method for developing extensible, efficient and readable parallel computational models

    NASA Astrophysics Data System (ADS)

    Honkonen, I.

    2014-07-01

    I present a method for developing extensible and modular computational models without sacrificing serial or parallel performance or source code readability. By using a generic simulation cell method I show that it is possible to combine several distinct computational models to run in the same computational grid without requiring any modification of existing code. This is an advantage for the development and testing of computational modeling software as each submodel can be developed and tested independently and subsequently used without modification in a more complex coupled program. Support for parallel programming is also provided by allowing users to select which simulation variables to transfer between processes via a Message Passing Interface library. This allows the communication strategy of a program to be formalized by explicitly stating which variables must be transferred between processes for the correct functionality of each submodel and the entire program. The generic simulation cell class presented here requires a C++ compiler that supports variadic templates which were standardized in 2011 (C++11). The code is available at: https://github.com/nasailja/gensimcell for everyone to use, study, modify and redistribute; those that do are kindly requested to cite this work.

  18. A generic simulation cell method for developing extensible, efficient and readable parallel computational models

    NASA Astrophysics Data System (ADS)

    Honkonen, I.

    2015-03-01

    I present a method for developing extensible and modular computational models without sacrificing serial or parallel performance or source code readability. By using a generic simulation cell method I show that it is possible to combine several distinct computational models to run in the same computational grid without requiring modification of existing code. This is an advantage for the development and testing of, e.g., geoscientific software as each submodel can be developed and tested independently and subsequently used without modification in a more complex coupled program. An implementation of the generic simulation cell method presented here, generic simulation cell class (gensimcell), also includes support for parallel programming by allowing model developers to select which simulation variables of, e.g., a domain-decomposed model to transfer between processes via a Message Passing Interface (MPI) library. This allows the communication strategy of a program to be formalized by explicitly stating which variables must be transferred between processes for the correct functionality of each submodel and the entire program. The generic simulation cell class requires a C++ compiler that supports a version of the language standardized in 2011 (C++11). The code is available at https://github.com/nasailja/gensimcell for everyone to use, study, modify and redistribute; those who do are kindly requested to acknowledge and cite this work.

  19. SEMICONDUCTOR DEVICES Parallel readout of two-element CdZnTe detectors with real-time digital signal processing

    NASA Astrophysics Data System (ADS)

    Zhubin, Shi; Linjun, Wang; Kaifeng, Qin; Jiahua, Min; Jijun, Zhang; Xiaoyan, Liang; Jian, Huang; Ke, Tang; Yiben, Xia

    2010-12-01

    Readout electronics, especially digital electronics, for two-element CdZnTe (CZT) detectors in parallel are developed. The preliminary results show the detection efficiency of the two-element CZT detectors in parallel with analog electronics is as many as 1.8 and 2.1 times the single ones, and the energy resolution (FWHM) is limited by that of the single one by the means of analog electronics. However, the digital method for signal processing will be sufficiently better by contrast with an analog method especially in energy resolution. The energy resolution by the means of digital electronics can be improved by about 26.67%, compared to that only with analog electronics, while their detection efficiency is almost the same. The cause for this difference is also discussed.

  20. Learning through Action: Parallel Learning Processes in Children and Adults

    ERIC Educational Resources Information Center

    Ethridge, Elizabeth A.; Branscomb, Kathryn R.

    2009-01-01

    Experiential learning has become an essential part of many educational settings from infancy through adulthood. While the effectiveness of active learning has been evaluated in youth and adult settings, few known studies have compared the learning processes of children and adults within the same project. This article contrasts the active learning…

  1. Parallel computing for simultaneous iterative tomographic imaging by graphics processing units

    NASA Astrophysics Data System (ADS)

    Bello-Maldonado, Pedro D.; López, Ricardo; Rogers, Colleen; Jin, Yuanwei; Lu, Enyue

    2016-05-01

    In this paper, we address the problem of accelerating inversion algorithms for nonlinear acoustic tomographic imaging by parallel computing on graphics processing units (GPUs). Nonlinear inversion algorithms for tomographic imaging often rely on iterative algorithms for solving an inverse problem, thus computationally intensive. We study the simultaneous iterative reconstruction technique (SIRT) for the multiple-input-multiple-output (MIMO) tomography algorithm which enables parallel computations of the grid points as well as the parallel execution of multiple source excitation. Using graphics processing units (GPUs) and the Compute Unified Device Architecture (CUDA) programming model an overall improvement of 26.33x was achieved when combining both approaches compared with sequential algorithms. Furthermore we propose an adaptive iterative relaxation factor and the use of non-uniform weights to improve the overall convergence of the algorithm. Using these techniques, fast computations can be performed in parallel without the loss of image quality during the reconstruction process.

  2. Connectionism, parallel constraint satisfaction processes, and gestalt principles: (re) introducing cognitive dynamics to social psychology.

    PubMed

    Read, S J; Vanman, E J; Miller, L C

    1997-01-01

    We argue that recent work in connectionist modeling, in particular the parallel constraint satisfaction processes that are central to many of these models, has great importance for understanding issues of both historical and current concern for social psychologists. We first provide a brief description of connectionist modeling, with particular emphasis on parallel constraint satisfaction processes. Second, we examine the tremendous similarities between parallel constraint satisfaction processes and the Gestalt principles that were the foundation for much of modem social psychology. We propose that parallel constraint satisfaction processes provide a computational implementation of the principles of Gestalt psychology that were central to the work of such seminal social psychologists as Asch, Festinger, Heider, and Lewin. Third, we then describe how parallel constraint satisfaction processes have been applied to three areas that were key to the beginnings of modern social psychology and remain central today: impression formation and causal reasoning, cognitive consistency (balance and cognitive dissonance), and goal-directed behavior. We conclude by discussing implications of parallel constraint satisfaction principles for a number of broader issues in social psychology, such as the dynamics of social thought and the integration of social information within the narrow time frame of social interaction.

  3. Architecture and design of a 500-MHz gallium-arsenide processing element for a parallel supercomputer

    NASA Technical Reports Server (NTRS)

    Fouts, Douglas J.; Butner, Steven E.

    1991-01-01

    The design of the processing element of GASP, a GaAs supercomputer with a 500-MHz instruction issue rate and 1-GHz subsystem clocks, is presented. The novel, functionally modular, block data flow architecture of GASP is described. The architecture and design of a GASP processing element is then presented. The processing element (PE) is implemented in a hybrid semiconductor module with 152 custom GaAs ICs of eight different types. The effects of the implementation technology on both the system-level architecture and the PE design are discussed. SPICE simulations indicate that parts of the PE are capable of being clocked at 1 GHz, while the rest of the PE uses a 500-MHz clock. The architecture utilizes data flow techniques at a program block level, which allows efficient execution of parallel programs while maintaining reasonably good performance on sequential programs. A simulation study of the architecture indicates that an instruction execution rate of over 30,000 MIPS can be attained with 65 PEs.

  4. Sculpting in cyberspace: Parallel processing the development of new software

    NASA Technical Reports Server (NTRS)

    Fisher, Rob

    1993-01-01

    Stimulating creativity in problem solving, particularly where software development is involved, is applicable to many disciplines. Metaphorical thinking keeps the problem in focus but in a different light, jarring people out of their mental ruts and sparking fresh insights. It forces the mind to stretch to find patterns between dissimilar concepts, in the hope of discovering unusual ideas in odd associations (Technology Review January 1993, p. 37). With a background in Engineering and Visual Design from MIT, I have for the past 30 years pursued a career as a sculptor of interdisciplinary monumental artworks that bridge the fields of science, engineering and art. Since 1979, I have pioneered the application of computer simulation to solve the complex problems associated with these projects. A recent project for the roof of the Carnegie Science Center in Pittsburgh made particular use of the metaphoric creativity technique described above. The problem-solving process led to the creation of hybrid software combining scientific, architectural and engineering visualization techniques. David Steich, a Doctoral Candidate in Electrical Engineering at Penn State, was commissioned to develop special software that enabled me to create innovative free-form sculpture. This paper explores the process of inventing the software through a detailed analysis of the interaction between an artist and a computer programmer.

  5. Efficient iteration in data-parallel programs with irregular and dynamically distributed data structures

    SciTech Connect

    Littlefield, R.J.

    1990-02-01

    To implement an efficient data-parallel program on a non-shared memory MIMD multicomputer, data and computations must be properly partitioned to achieve good load balance and locality of reference. Programs with irregular data reference patterns often require irregular partitions. Although good partitions may be easy to determine, they can be difficult or impossible to implement in programming languages that provide only regular data distributions, such as blocked or cyclic arrays. We are developing Onyx, a programming system that provides a shared memory model of distributed data structures and extends the concept of data distribution to include irregular and dynamic distributions. This provides a powerful means to specify irregular partitions. Perhaps surprisingly, programs using it can also execute efficiently. In this paper, we describe and evaluate the Onyx implementation of a model problem that repeatedly executes an irregular but fixed data reference pattern. On an NCUBE hypercube, the speed of the Onyx implementation is comparable to that of carefully handwritten message-passing code.

  6. An efficient parallel algorithm: Poststack and prestack Kirchhoff 3D depth migration using flexi-depth iterations

    NASA Astrophysics Data System (ADS)

    Rastogi, Richa; Srivastava, Abhishek; Khonde, Kiran; Sirasala, Kirannmayi M.; Londhe, Ashutosh; Chavhan, Hitesh

    2015-07-01

    This paper presents an efficient parallel 3D Kirchhoff depth migration algorithm suitable for current class of multicore architecture. The fundamental Kirchhoff depth migration algorithm exhibits inherent parallelism however, when it comes to 3D data migration, as the data size increases the resource requirement of the algorithm also increases. This challenges its practical implementation even on current generation high performance computing systems. Therefore a smart parallelization approach is essential to handle 3D data for migration. The most compute intensive part of Kirchhoff depth migration algorithm is the calculation of traveltime tables due to its resource requirements such as memory/storage and I/O. In the current research work, we target this area and develop a competent parallel algorithm for post and prestack 3D Kirchhoff depth migration, using hybrid MPI+OpenMP programming techniques. We introduce a concept of flexi-depth iterations while depth migrating data in parallel imaging space, using optimized traveltime table computations. This concept provides flexibility to the algorithm by migrating data in a number of depth iterations, which depends upon the available node memory and the size of data to be migrated during runtime. Furthermore, it minimizes the requirements of storage, I/O and inter-node communication, thus making it advantageous over the conventional parallelization approaches. The developed parallel algorithm is demonstrated and analysed on Yuva II, a PARAM series of supercomputers. Optimization, performance and scalability experiment results along with the migration outcome show the effectiveness of the parallel algorithm.

  7. The role of parallelism in the real-time processing of anaphora

    PubMed Central

    Poirier, Josée; Walenski, Matthew; Shapiro, Lewis P.

    2012-01-01

    Parallelism effects refer to the facilitated processing of a target structure when it follows a similar, parallel structure. In coordination, a parallelism-related conjunction triggers the expectation that a second conjunct with the same structure as the first conjunct should occur. It has been proposed that parallelism effects reflect the use of the first structure as a template that guides the processing of the second. In this study, we examined the role of parallelism in real-time anaphora resolution by charting activation patterns in coordinated constructions containing anaphora, Verb-Phrase Ellipsis (VPE) and Noun-Phrase Traces (NP-traces). Specifically, we hypothesised that an expectation of parallelism would incite the parser to assume a structure similar to the first conjunct in the second, anaphora-containing conjunct. The speculation of a similar structure would result in early postulation of covert anaphora. Experiment 1 confirms that following a parallelism-related conjunction, first-conjunct material is activated in the second conjunct. Experiment 2 reveals that an NP-trace in the second conjunct is posited immediately where licensed, which is earlier than previously reported in the literature. In light of our findings, we propose an intricate relation between structural expectations and anaphor resolution. PMID:23741080

  8. Parallel versus sequential processing in print and braille reading.

    PubMed

    Veispak, Anneli; Boets, Bart; Ghesquière, Pol

    2012-01-01

    In the current study we investigated word, pseudoword and story reading in Dutch speaking braille and print readers. To examine developmental patterns, these reading skills were assessed in both children and adults. The results reveal that braille readers read less accurately and fast than print readers. While item length has no impact on word reading accuracy and speed in the group of print readers, it has a significant impact on reading accuracy and speed in the group of braille readers, particularly in the younger sample. This suggests that braille readers rely more strongly on an enduring sequential reading strategy. Comparison of the different reading tasks suggests that the advantage in accuracy and speed of reading in adult as compared to young braille readers is achieved through semantic top-down processing.

  9. Non-parallel processing: Gendered attrition in academic computer science

    NASA Astrophysics Data System (ADS)

    Cohoon, Joanne Louise Mcgrath

    2000-10-01

    This dissertation addresses the issue of disproportionate female attrition from computer science as an instance of gender segregation in higher education. By adopting a theoretical framework from organizational sociology, it demonstrates that the characteristics and processes of computer science departments strongly influence female retention. The empirical data identifies conditions under which women are retained in the computer science major at comparable rates to men. The research for this dissertation began with interviews of students, faculty, and chairpersons from five computer science departments. These exploratory interviews led to a survey of faculty and chairpersons at computer science and biology departments in Virginia. The data from these surveys are used in comparisons of the computer science and biology disciplines, and for statistical analyses that identify which departmental characteristics promote equal attrition for male and female undergraduates in computer science. This three-pronged methodological approach of interviews, discipline comparisons, and statistical analyses shows that departmental variation in gendered attrition rates can be explained largely by access to opportunity, relative numbers, and other characteristics of the learning environment. Using these concepts, this research identifies nine factors that affect the differential attrition of women from CS departments. These factors are: (1) The gender composition of enrolled students and faculty; (2) Faculty turnover; (3) Institutional support for the department; (4) Preferential attitudes toward female students; (5) Mentoring and supervising by faculty; (6) The local job market, starting salaries, and competitiveness of graduates; (7) Emphasis on teaching; and (8) Joint efforts for student success. This work contributes to our understanding of the gender segregation process in higher education. In addition, it contributes information that can lead to effective solutions for an

  10. Note on parallel processing techniques for algebraic equations, ordinary differential equations and partial differential equations

    SciTech Connect

    Allidina, A.Y.; Malinowski, K.; Singh, M.G.

    1982-12-01

    The possibilities were explored for enhancing parallelism in the simulation of systems described by algebraic equations, ordinary differential equations and partial differential equations. These techniques, using multiprocessors, were developed to speed up simulations, e.g. for nuclear accidents. Issues involved in their design included suitable approximations to bring the problem into a numerically manageable form and a numerical procedure to perform the computations necessary to solve the problem accurately. Parallel processing techniques used as simulation procedures, and a design of a simulation scheme and simulation procedure employing parallel computer facilities, were both considered.

  11. Adapting high-level language programs for parallel processing using data flow

    NASA Technical Reports Server (NTRS)

    Standley, Hilda M.

    1988-01-01

    EASY-FLOW, a very high-level data flow language, is introduced for the purpose of adapting programs written in a conventional high-level language to a parallel environment. The level of parallelism provided is of the large-grained variety in which parallel activities take place between subprograms or processes. A program written in EASY-FLOW is a set of subprogram calls as units, structured by iteration, branching, and distribution constructs. A data flow graph may be deduced from an EASY-FLOW program.

  12. Integration Of Parallel Image Processing With Symbolic And Neural Computations For Imagery Exploitation

    NASA Astrophysics Data System (ADS)

    Roman, Evelyn

    1990-02-01

    In this paper we discuss the work being done at Itek combining parallel, symbolic, and neural methodologies at different stages of processing for imagery exploitation. We describe a prototype system we have been implementing combining real-time parallel image processing on an 8-stage parallel image-processing engine (PIPE) computer with expert system software such as our Multi-Sensor Exploitation Assistant system on the Symbolics LISP machine and with neural computations on the PIPE and on its host IBM AT for target recognition and change detection applications. We also provide a summary of basic neural concepts, and show the commonality between neural nets and related mathematics, artificial intelligence, and traditional image processing concepts. This provides us with numerous choices for the implementation of constraint satisfaction, transformational invariance, inference and representational mechanisms, and software lifecycle engineering methodologies in the different computational layers. Our future work may include optical processing as well, for a real-time capability complementing the PIPE's.

  13. Comparisons of elastic and rigid blade-element rotor models using parallel processing technology for piloted simulations

    NASA Technical Reports Server (NTRS)

    Hill, Gary; Duval, Ronald W.; Green, John A.; Huynh, Loc C.

    1991-01-01

    A piloted comparison of rigid and aeroelastic blade-element rotor models was conducted at the Crew Station Research and Development Facility (CSRDF) at Ames Research Center. A simulation development and analysis tool, FLIGHTLAB, was used to implement these models in real time using parallel processing technology. Pilot comments and quantitative analysis performed both on-line and off-line confirmed that elastic degrees of freedom significantly affect perceived handling qualities. Trim comparisons show improved correlation with flight test data when elastic modes are modeled. The results demonstrate the efficiency with which the mathematical modeling sophistication of existing simulation facilities can be upgraded using parallel processing, and the importance of these upgrades to simulation fidelity.

  14. Parallel computer processing and modeling: applications for the ICU

    NASA Astrophysics Data System (ADS)

    Baxter, Grant; Pranger, L. Alex; Draghic, Nicole; Sims, Nathaniel M.; Wiesmann, William P.

    2003-07-01

    Current patient monitoring procedures in hospital intensive care units (ICUs) generate vast quantities of medical data, much of which is considered extemporaneous and not evaluated. Although sophisticated monitors to analyze individual types of patient data are routinely used in the hospital setting, this equipment lacks high order signal analysis tools for detecting long-term trends and correlations between different signals within a patient data set. Without the ability to continuously analyze disjoint sets of patient data, it is difficult to detect slow-forming complications. As a result, the early onset of conditions such as pneumonia or sepsis may not be apparent until the advanced stages. We report here on the development of a distributed software architecture test bed and software medical models to analyze both asynchronous and continuous patient data in real time. Hardware and software has been developed to support a multi-node distributed computer cluster capable of amassing data from multiple patient monitors and projecting near and long-term outcomes based upon the application of physiologic models to the incoming patient data stream. One computer acts as a central coordinating node; additional computers accommodate processing needs. A simple, non-clinical model for sepsis detection was implemented on the system for demonstration purposes. This work shows exceptional promise as a highly effective means to rapidly predict and thereby mitigate the effect of nosocomial infections.

  15. Design and implementation of the parallel processing system of multi-channel polarization images

    NASA Astrophysics Data System (ADS)

    Li, Zhi-yong; Huang, Qin-chao

    2013-08-01

    Compared with traditional optical intensity image processing, polarization images processing has two main problems. One is that the amount of data is larger. The other is that processing tasks is more complex. To resolve these problems, the parallel processing system of multi-channel polarization images is designed by the multi-DSP technique. It contains a communication control unit (CCU) and a data processing array (DPA). CCU controls communications inside and outside the system. Its logics are designed by a FPGA chip. DPA is made up of four Digital Signal Processor (DSP) chips, which are interlinked by the loose coupling method. DPA implements processing tasks including images registration and images synthesis by parallel processing methods. The polarization images parallel processing model is designed on multi levels including the system task, the algorithm and the operation. Its program is designed by the assemble language. While the polarization image resolution is 782x582 pixels, the pixel data length is 12 bits in the experiment. After it received 3 channels of polarization image simultaneously, this system implements parallel task to acquire the target polarization characteristics. Experimental results show that this system has good real-time and reliability. The processing time of images registration is 293.343ms while the registration accuracy achieves 0.5 pixel. The processing time of images synthesis is 3.199ms.

  16. Designing efficient parallel algorithms on mesh-connected computers with multiple broadcasting

    SciTech Connect

    Chen, Y.C.; Chen, W.T. ); Chen, G.H. ); Sheu, J.P. )

    1990-04-01

    Semigroup and prefix computations on two-dimensional mesh-connected computers with multiple broadcasting (2-MCCMB's) are studied in this paper. Previously, only square 2-MCCMB's with N processing elements were considered or semigroup computations of N data items, and O(N{sup 1/6}) time was required. It is found that square machines are not the best form for semigroup computations, and an O(N{sup 1/8}) time algorithm is thus derived on an N{sup 5/8} {times} N{sup 3/8} rectangular 2-MCCMB. This time complexity can be further reduced to O(N{sup 1/9}) if fewer PE's are used. Following the same way, parallel algorithms for prefix computations are also derived with the same time complexities.

  17. Parallel flow accumulation algorithms for graphical processing units with application to RUSLE model

    NASA Astrophysics Data System (ADS)

    Sten, Johan; Lilja, Harri; Hyväluoma, Jari; Westerholm, Jan; Aspnäs, Mats

    2016-04-01

    Digital elevation models (DEMs) are widely used in the modeling of surface hydrology, which typically includes the determination of flow directions and flow accumulation. The use of high-resolution DEMs increases the accuracy of flow accumulation computation, but as a drawback, the computational time may become excessively long if large areas are analyzed. In this paper we investigate the use of graphical processing units (GPUs) for efficient flow accumulation calculations. We present two new parallel flow accumulation algorithms based on dependency transfer and topological sorting and compare them to previously published flow transfer and indegree-based algorithms. We benchmark the GPU implementations against industry standards, ArcGIS and SAGA. With the flow-transfer D8 flow routing model and binary input data, a speed up of 19 is achieved compared to ArcGIS and 15 compared to SAGA. We show that on GPUs the topological sort-based flow accumulation algorithm leads on average to a speedup by a factor of 7 over the flow-transfer algorithm. Thus a total speed up of the order of 100 is achieved. We test the algorithms by applying them to the Revised Universal Soil Loss Equation (RUSLE) erosion model. For this purpose we present parallel versions of the slope, LS factor and RUSLE algorithms and show that the RUSLE erosion results for an area of 12 km x 24 km containing 72 million cells can be calculated in less than a second. Since flow accumulation is needed in many hydrological models, the developed algorithms may find use in many other applications than RUSLE modeling. The algorithm based on topological sorting is particularly promising for dynamic hydrological models where flow accumulations are repeatedly computed over an unchanged DEM.

  18. Parallels between a Collaborative Research Process and the Middle Level Philosophy

    ERIC Educational Resources Information Center

    Dever, Robin; Ross, Diane; Miller, Jennifer; White, Paula; Jones, Karen

    2014-01-01

    The characteristics of the middle level philosophy as described in This We Believe closely parallel the collaborative research process. The journey of one research team is described in relationship to these characteristics. The collaborative process includes strengths such as professional relationships, professional development, courageous…

  19. Parallel Processing of the Target Language during Source Language Comprehension in Interpreting

    ERIC Educational Resources Information Center

    Dong, Yanping; Lin, Jiexuan

    2013-01-01

    Two experiments were conducted to test the hypothesis that the parallel processing of the target language (TL) during source language (SL) comprehension in interpreting may be influenced by two factors: (i) link strength from SL to TL, and (ii) the interpreter's cognitive resources supplement to TL processing during SL comprehension. The…

  20. A computationally efficient parallel Levenberg-Marquardt algorithm for highly parameterized inverse model analyses

    DOE PAGES

    Lin, Youzuo; O'Malley, Daniel; Vesselinov, Velimir V.

    2016-08-19

    Inverse modeling seeks model parameters given a set of observations. However, for practical problems because the number of measurements is often large and the model parameters are also numerous, conventional methods for inverse modeling can be computationally expensive. We have developed a new, computationally-efficient parallel Levenberg-Marquardt method for solving inverse modeling problems with a highly parameterized model space. Levenberg-Marquardt methods require the solution of a linear system of equations which can be prohibitively expensive to compute for moderate to large-scale problems. Our novel method projects the original linear problem down to a Krylov subspace, such that the dimensionality of themore » problem can be significantly reduced. Furthermore, we store the Krylov subspace computed when using the first damping parameter and recycle the subspace for the subsequent damping parameters. The efficiency of our new inverse modeling algorithm is significantly improved using these computational techniques. We apply this new inverse modeling method to invert for random transmissivity fields in 2D and a random hydraulic conductivity field in 3D. Our algorithm is fast enough to solve for the distributed model parameters (transmissivity) in the model domain. The algorithm is coded in Julia and implemented in the MADS computational framework (http://mads.lanl.gov). By comparing with Levenberg-Marquardt methods using standard linear inversion techniques such as QR or SVD methods, our Levenberg-Marquardt method yields a speed-up ratio on the order of ~101 to ~102 in a multi-core computational environment. Furthermore, our new inverse modeling method is a powerful tool for characterizing subsurface heterogeneity for moderate- to large-scale problems.« less

  1. Parallel artificial liquid membrane extraction as an efficient tool for removal of phospholipids from human plasma.

    PubMed

    Ask, Kristine Skoglund; Bardakci, Turgay; Parmer, Marthe Petrine; Halvorsen, Trine Grønhaug; Øiestad, Elisabeth Leere; Pedersen-Bjergaard, Stig; Gjelstad, Astrid

    2016-09-10

    Generic Parallel Artificial Liquid Membrane Extraction (PALME) methods for non-polar basic and non-polar acidic drugs from human plasma were investigated with respect to phospholipid removal. In both cases, extractions in 96-well format were performed from plasma (125μL), through 4μL organic solvent used as supported liquid membranes (SLMs), and into 50μL aqueous acceptor solutions. The acceptor solutions were subsequently analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) using in-source fragmentation and monitoring the m/z 184→184 transition for investigation of phosphatidylcholines (PC), sphingomyelins (SM), and lysophosphatidylcholines (Lyso-PC). In both generic methods, no phospholipids were detected in the acceptor solutions. Thus, PALME appeared to be highly efficient for phospholipid removal. To further support this, qualitative (post-column infusion) and quantitative matrix effects were investigated with fluoxetine, fluvoxamine, and quetiapine as model analytes. No signs of matrix effects were observed. Finally, PALME was evaluated for the aforementioned drug substances, and data were in accordance with European Medicines Agency (EMA) guidelines. PMID:27433988

  2. Efficient massively parallel simulation of dynamic channel assignment schemes for wireless cellular communications

    NASA Technical Reports Server (NTRS)

    Greenberg, Albert G.; Lubachevsky, Boris D.; Nicol, David M.; Wright, Paul E.

    1994-01-01

    Fast, efficient parallel algorithms are presented for discrete event simulations of dynamic channel assignment schemes for wireless cellular communication networks. The driving events are call arrivals and departures, in continuous time, to cells geographically distributed across the service area. A dynamic channel assignment scheme decides which call arrivals to accept, and which channels to allocate to the accepted calls, attempting to minimize call blocking while ensuring co-channel interference is tolerably low. Specifically, the scheme ensures that the same channel is used concurrently at different cells only if the pairwise distances between those cells are sufficiently large. Much of the complexity of the system comes from ensuring this separation. The network is modeled as a system of interacting continuous time automata, each corresponding to a cell. To simulate the model, conservative methods are used; i.e., methods in which no errors occur in the course of the simulation and so no rollback or relaxation is needed. Implemented on a 16K processor MasPar MP-1, an elegant and simple technique provides speedups of about 15 times over an optimized serial simulation running on a high speed workstation. A drawback of this technique, typical of conservative methods, is that processor utilization is rather low. To overcome this, new methods were developed that exploit slackness in event dependencies over short intervals of time, thereby raising the utilization to above 50 percent and the speedup over the optimized serial code to about 120 times.

  3. Highly-multiplexed barcode sequencing: an efficient method for parallel analysis of pooled samples

    PubMed Central

    Smith, Andrew M.; Heisler, Lawrence E.; St.Onge, Robert P.; Farias-Hesson, Eveline; Wallace, Iain M.; Bodeau, John; Harris, Adam N.; Perry, Kathleen M.; Giaever, Guri; Pourmand, Nader; Nislow, Corey

    2010-01-01

    Next-generation sequencing has proven an extremely effective technology for molecular counting applications where the number of sequence reads provides a digital readout for RNA-seq, ChIP-seq, Tn-seq and other applications. The extremely large number of sequence reads that can be obtained per run permits the analysis of increasingly complex samples. For lower complexity samples, however, a point of diminishing returns is reached when the number of counts per sequence results in oversampling with no increase in data quality. A solution to making next-generation sequencing as efficient and affordable as possible involves assaying multiple samples in a single run. Here, we report the successful 96-plexing of complex pools of DNA barcoded yeast mutants and show that such ‘Bar-seq’ assessment of these samples is comparable with data provided by barcode microarrays, the current benchmark for this application. The cost reduction and increased throughput permitted by highly multiplexed sequencing will greatly expand the scope of chemogenomics assays and, equally importantly, the approach is suitable for other sequence counting applications that could benefit from massive parallelization. PMID:20460461

  4. Managing internode data communications for an uninitialized process in a parallel computer

    DOEpatents

    Archer, Charles J; Blocksome, Michael A; Miller, Douglas R; Parker, Jeffrey J; Ratterman, Joseph D; Smith, Brian E

    2014-05-20

    A parallel computer includes nodes, each having main memory and a messaging unit (MU). Each MU includes computer memory, which in turn includes, MU message buffers. Each MU message buffer is associated with an uninitialized process on the compute node. In the parallel computer, managing internode data communications for an uninitialized process includes: receiving, by an MU of a compute node, one or more data communications messages in an MU message buffer associated with an uninitialized process on the compute node; determining, by an application agent, that the MU message buffer associated with the uninitialized process is full prior to initialization of the uninitialized process; establishing, by the application agent, a temporary message buffer for the uninitialized process in main computer memory; and moving, by the application agent, data communications messages from the MU message buffer associated with the uninitialized process to the temporary message buffer in main computer memory.

  5. Industrial burner and process efficiency program

    NASA Astrophysics Data System (ADS)

    Huebner, S. R.; Prakash, S. N.

    1981-03-01

    A laboratory prototype burner which is compatible with a FM (frequency modulation) combustion control system where temperature control is accomplished by regulating the ratio of burner on-time to burner off-time was developed. This multifuel (natural gas and No. 2 fuel oil) high velocity burner is capable of repeated pulse ignition at maximum rated capability (1 million Btu-hour) with preheated air (from ambient to 1100F). A digital control in the FM mode was developed. Experimental data from tests in a laboratory furnace indicated that when applied to a batch type thermal process where appreciable turndown is presently obtained by excess air operation, the FM combustion system provides improvements in process fuel efficiency and gains in productivity.

  6. Maximum efficiency of the collisional Penrose process

    NASA Astrophysics Data System (ADS)

    Zaslavskii, O. B.

    2016-09-01

    We consider the collision of two particles that move in the equatorial plane near a general stationary rotating axially symmetric extremal black hole. One of the particles is critical (with fine-tuned parameters) and moves in the outward direction. The second particle (usual, not fine-tuned) comes from infinity. We examine the efficiency η of the collisional Penrose process. There are two relevant cases here: a particle falling into a black hole after collision (i) is heavy or (ii) has a finite mass. We show that the maximum of η in case (ii) is less than or equal to that in case (i). It is argued that for superheavy particles, the bound applies to nonequatorial motion as well. As an example, we analyze collision in the Kerr-Newman background. When the bound is the same for processes (i) and (ii), η =3 for this metric. For the Kerr black hole, recent results in the literature are reproduced.

  7. A Novel and Efficient One-Step Parallel Synthesis of Dibenzopyranones via Suzuki-Miyaura Cross Coupling

    PubMed Central

    Vishnumurthy, Kodumuru; Makriyannis, Alexandros

    2010-01-01

    Microwave promoted novel and efficient one-step parallel synthesis of dibenzopyranones and heterocyclic analogues from bromo arylcarboxylates and o-hydroxyarylboronic acids via Suzuki-Miyaura cross coupling reaction is described. Spontaneous lactonization gave dibenzopyranones and heterocyclic analogues bearing electron donating and withdrawing groups on both aromatic rings in good to excellent yields. PMID:20831265

  8. a Hadoop-Based Distributed Framework for Efficient Managing and Processing Big Remote Sensing Images

    NASA Astrophysics Data System (ADS)

    Wang, C.; Hu, F.; Hu, X.; Zhao, S.; Wen, W.; Yang, C.

    2015-07-01

    Various sensors from airborne and satellite platforms are producing large volumes of remote sensing images for mapping, environmental monitoring, disaster management, military intelligence, and others. However, it is challenging to efficiently storage, query and process such big data due to the data- and computing- intensive issues. In this paper, a Hadoop-based framework is proposed to manage and process the big remote sensing data in a distributed and parallel manner. Especially, remote sensing data can be directly fetched from other data platforms into the Hadoop Distributed File System (HDFS). The Orfeo toolbox, a ready-to-use tool for large image processing, is integrated into MapReduce to provide affluent image processing operations. With the integration of HDFS, Orfeo toolbox and MapReduce, these remote sensing images can be directly processed in parallel in a scalable computing environment. The experiment results show that the proposed framework can efficiently manage and process such big remote sensing data.

  9. Parallel distributed processing and neural networks: origins, methodology and cognitive functions.

    PubMed

    Parks, R W; Long, D L; Levine, D S; Crockett, D J; McGeer, E G; McGeer, P L; Dalton, I E; Zec, R F; Becker, R E; Coburn, K L

    1991-10-01

    Parallel Distributed Processing (PDP), a computational methodology with origins in Associationism, is used to provide empirical information regarding neurobiological systems. Recently, supercomputers have enabled neuroscientists to model brain behavior-relationships. An overview of supercomputer architecture demonstrates the advantages of parallel over serial processing. Histological data provide physical evidence of the parallel distributed nature of certain aspects of the human brain, as do corresponding computer simulations. Whereas sensory networks follow more sequential neural network pathways, in vivo brain imaging studies of attention and rudimentary language tasks appear to involve multiple cortical and subcortical areas. Controversy remains as to whether associative models or Artificial Intelligence symbolic models better reflect neural networks of cognitive functions; however, considerable interest has shifted towards associative models.

  10. Processing communications events in parallel active messaging interface by awakening thread from wait state

    DOEpatents

    Archer, Charles J; Blocksome, Michael A; Ratterman, Joseph D; Smith, Brian E

    2013-10-22

    Processing data communications events in a parallel active messaging interface (`PAMI`) of a parallel computer that includes compute nodes that execute a parallel application, with the PAMI including data communications endpoints, and the endpoints are coupled for data communications through the PAMI and through other data communications resources, including determining by an advance function that there are no actionable data communications events pending for its context, placing by the advance function its thread of execution into a wait state, waiting for a subsequent data communications event for the context; responsive to occurrence of a subsequent data communications event for the context, awakening by the thread from the wait state; and processing by the advance function the subsequent data communications event now pending for the context.

  11. Friction Stir Processing for Efficient Manufacturing

    SciTech Connect

    Mr. Christopher B. Smith; Dr. Oyelayo Ajayi

    2012-01-31

    Friction at contacting surfaces in relative motion is a major source of parasitic energy loss in machine systems and manufacturing processes. Consequently, friction reduction usually translates to efficiency gain and reduction in energy consumption. Furthermore, friction at surfaces eventually leads to wear and failure of the components thereby compromising reliability and durability. In order to reduce friction and wear in tribological components, material surfaces are often hardened by a variety of methods, including conventional heat treatment, laser surface hardening, and thin-film coatings. While these surface treatments are effective when used in conjunction with lubrication to prevent failure, they are all energy intensive and could potentially add significant cost. A new concept for surface hardening of metallic materials and components is Friction Stir Processing (FSP). Compared to the current surface hardening technologies, FSP is more energy efficient has no emission or waste by products and may result in better tribological performance. FSP involves plunging a rotating tool to a predetermined depth (case layer thickness) and translating the FSP tool along the area to be processed. This action of the tool produces heating and severe plastic deformation of the processed area. For steel the temperature is high enough to cause phase transformation, ultimately forming hard martensitic phase. Indeed, FSP has been used for surface modification of several metals and alloys so as to homogenize the microstructure and refine the grain size, both of which led to improved fatigue and corrosion resistance. Based on the effect of FSP on near-surface layer material, it was expected to have beneficial effects on friction and wear performance of metallic materials. However, little or no knowledge existed on the impact of FSP concerning friction and wear performance the subject of the this project and final report. Specifically for steel, which is the most dominant

  12. Parallel Digital Watermarking Process on Ultrasound Medical Images in Multicores Environment

    PubMed Central

    Khor, Hui Liang; Liew, Siau-Chuin; Zain, Jasni Mohd.

    2016-01-01

    With the advancement of technology in communication network, it facilitated digital medical images transmitted to healthcare professionals via internal network or public network (e.g., Internet), but it also exposes the transmitted digital medical images to the security threats, such as images tampering or inserting false data in the images, which may cause an inaccurate diagnosis and treatment. Medical image distortion is not to be tolerated for diagnosis purposes; thus a digital watermarking on medical image is introduced. So far most of the watermarking research has been done on single frame medical image which is impractical in the real environment. In this paper, a digital watermarking on multiframes medical images is proposed. In order to speed up multiframes watermarking processing time, a parallel watermarking processing on medical images processing by utilizing multicores technology is introduced. An experiment result has shown that elapsed time on parallel watermarking processing is much shorter than sequential watermarking processing. PMID:26981111

  13. Parallel Digital Watermarking Process on Ultrasound Medical Images in Multicores Environment.

    PubMed

    Khor, Hui Liang; Liew, Siau-Chuin; Zain, Jasni Mohd

    2016-01-01

    With the advancement of technology in communication network, it facilitated digital medical images transmitted to healthcare professionals via internal network or public network (e.g., Internet), but it also exposes the transmitted digital medical images to the security threats, such as images tampering or inserting false data in the images, which may cause an inaccurate diagnosis and treatment. Medical image distortion is not to be tolerated for diagnosis purposes; thus a digital watermarking on medical image is introduced. So far most of the watermarking research has been done on single frame medical image which is impractical in the real environment. In this paper, a digital watermarking on multiframes medical images is proposed. In order to speed up multiframes watermarking processing time, a parallel watermarking processing on medical images processing by utilizing multicores technology is introduced. An experiment result has shown that elapsed time on parallel watermarking processing is much shorter than sequential watermarking processing. PMID:26981111

  14. Parallel Digital Watermarking Process on Ultrasound Medical Images in Multicores Environment.

    PubMed

    Khor, Hui Liang; Liew, Siau-Chuin; Zain, Jasni Mohd

    2016-01-01

    With the advancement of technology in communication network, it facilitated digital medical images transmitted to healthcare professionals via internal network or public network (e.g., Internet), but it also exposes the transmitted digital medical images to the security threats, such as images tampering or inserting false data in the images, which may cause an inaccurate diagnosis and treatment. Medical image distortion is not to be tolerated for diagnosis purposes; thus a digital watermarking on medical image is introduced. So far most of the watermarking research has been done on single frame medical image which is impractical in the real environment. In this paper, a digital watermarking on multiframes medical images is proposed. In order to speed up multiframes watermarking processing time, a parallel watermarking processing on medical images processing by utilizing multicores technology is introduced. An experiment result has shown that elapsed time on parallel watermarking processing is much shorter than sequential watermarking processing.

  15. Compressed bitmap indices for efficient query processing

    SciTech Connect

    Wu, Kesheng; Otoo, Ekow; Shoshani, Arie

    2001-09-30

    Many database applications make extensive use of bitmap indexing schemes. In this paper, we study how to improve the efficiencies of these indexing schemes by proposing new compression schemes for the bitmaps. Most compression schemes are designed primarily to achieve good compression. During query processing they can be orders of magnitude slower than their uncompressed counterparts. The new schemes are designed to bridge this performance gap by reducing compression effectiveness and improving operation speed. In a number of tests on both synthetic data and real application data, we found that the new schemes significantly outperform the well-known compression schemes while using only modestly more space. For example, compared to the Byte-aligned Bitmap Code, the new schemes are 12 times faster and it uses only 50 percent more space. The new schemes use much less space(<30 percent) than the uncompressed scheme and are faster in a majority of the test cases.

  16. High Performance Parallel Processing Project: Industrial computing initiative. Progress reports for fiscal year 1995

    SciTech Connect

    Koniges, A.

    1996-02-09

    This project is a package of 11 individual CRADA`s plus hardware. This innovative project established a three-year multi-party collaboration that is significantly accelerating the availability of commercial massively parallel processing computing software technology to U.S. government, academic, and industrial end-users. This report contains individual presentations from nine principal investigators along with overall program information.

  17. Parallel processing in the honeybee olfactory pathway: structure, function, and evolution.

    PubMed

    Rössler, Wolfgang; Brill, Martin F

    2013-11-01

    Animals face highly complex and dynamic olfactory stimuli in their natural environments, which require fast and reliable olfactory processing. Parallel processing is a common principle of sensory systems supporting this task, for example in visual and auditory systems, but its role in olfaction remained unclear. Studies in the honeybee focused on a dual olfactory pathway. Two sets of projection neurons connect glomeruli in two antennal-lobe hemilobes via lateral and medial tracts in opposite sequence with the mushroom bodies and lateral horn. Comparative studies suggest that this dual-tract circuit represents a unique adaptation in Hymenoptera. Imaging studies indicate that glomeruli in both hemilobes receive redundant sensory input. Recent simultaneous multi-unit recordings from projection neurons of both tracts revealed widely overlapping response profiles strongly indicating parallel olfactory processing. Whereas lateral-tract neurons respond fast with broad (generalistic) profiles, medial-tract neurons are odorant specific and respond slower. In analogy to "what-" and "where" subsystems in visual pathways, this suggests two parallel olfactory subsystems providing "what-" (quality) and "when" (temporal) information. Temporal response properties may support across-tract coincidence coding in higher centers. Parallel olfactory processing likely enhances perception of complex odorant mixtures to decode the diverse and dynamic olfactory world of a social insect.

  18. One Factor or Two Parallel Processes? Comorbidity and Development of Adolescent Anxiety and Depressive Disorder Symptoms

    ERIC Educational Resources Information Center

    Hale, William W., III; Raaijmakers, Quinten A. W.; Muris, Peter; van Hoof, Anne; Meeus, Wim H. J.

    2009-01-01

    Background: This study investigates whether anxiety and depressive disorder symptoms of adolescents from the general community are best described by a model that assumes they are indicative of one general factor or by a model that assumes they are two distinct disorders with parallel growth processes. Additional analyses were conducted to explore…

  19. Cocaine Use and Delinquent Behavior among High-Risk Youths: A Growth Model of Parallel Processes

    ERIC Educational Resources Information Center

    Dembo, Richard; Sullivan, Christopher

    2009-01-01

    We report the results of a parallel-process, latent growth model analysis examining the relationships between cocaine use and delinquent behavior among youths. The study examined a sample of 278 justice-involved juveniles completing at least one of three follow-up interviews as part of a National Institute on Drug Abuse-funded study. The results…

  20. Parallel Distributed Processing at 25: Further Explorations in the Microstructure of Cognition

    ERIC Educational Resources Information Center

    Rogers, Timothy T.; McClelland, James L.

    2014-01-01

    This paper introduces a special issue of "Cognitive Science" initiated on the 25th anniversary of the publication of "Parallel Distributed Processing" (PDP), a two-volume work that introduced the use of neural network models as vehicles for understanding cognition. The collection surveys the core commitments of the PDP…

  1. A Neurally Plausible Parallel Distributed Processing Model of Event-Related Potential Word Reading Data

    ERIC Educational Resources Information Center

    Laszlo, Sarah; Plaut, David C.

    2012-01-01

    The Parallel Distributed Processing (PDP) framework has significant potential for producing models of cognitive tasks that approximate how the brain performs the same tasks. To date, however, there has been relatively little contact between PDP modeling and data from cognitive neuroscience. In an attempt to advance the relationship between…

  2. Tracking the Continuity of Language Comprehension: Computer Mouse Trajectories Suggest Parallel Syntactic Processing

    ERIC Educational Resources Information Center

    Farmer, Thomas A.; Cargill, Sarah A.; Hindy, Nicholas C.; Dale, Rick; Spivey, Michael J.

    2007-01-01

    Although several theories of online syntactic processing assume the parallel activation of multiple syntactic representations, evidence supporting simultaneous activation has been inconclusive. Here, the continuous and non-ballistic properties of computer mouse movements are exploited, by recording their streaming x, y coordinates to procure…

  3. Psychodrama: A Creative Approach for Addressing Parallel Process in Group Supervision

    ERIC Educational Resources Information Center

    Hinkle, Michelle Gimenez

    2008-01-01

    This article provides a model for using psychodrama to address issues of parallel process during group supervision. Information on how to utilize the specific concepts and techniques of psychodrama in relation to group supervision is discussed. A case vignette of the model is provided.

  4. An Inconvenient Truth: An Application of the Extended Parallel Process Model

    ERIC Educational Resources Information Center

    Goodall, Catherine E.; Roberto, Anthony J.

    2008-01-01

    "An Inconvenient Truth" is an Academy Award-winning documentary about global warming presented by Al Gore. This documentary is appropriate for a lesson on fear appeals and the extended parallel process model (EPPM). The EPPM is concerned with the effects of perceived threat and efficacy on behavior change. Perceived threat is composed of an…

  5. Using the Extended Parallel Process Model to Examine Teachers' Likelihood of Intervening in Bullying

    ERIC Educational Resources Information Center

    Duong, Jeffrey; Bradshaw, Catherine P.

    2013-01-01

    Background: Teachers play a critical role in protecting students from harm in schools, but little is known about their attitudes toward addressing problems like bullying. Previous studies have rarely used theoretical frameworks, making it difficult to advance this area of research. Using the Extended Parallel Process Model (EPPM), we examined the…

  6. Parallel Process and Isomorphism: A Model for Decision Making in the Supervisory Triad

    ERIC Educational Resources Information Center

    Koltz, Rebecca L.; Odegard, Melissa A.; Feit, Stephen S.; Provost, Kent; Smith, Travis

    2012-01-01

    Parallel process and isomorphism are two supervisory concepts that are often discussed independently but rarely discussed in connection with each other. These two concepts, philosophically, have different historical roots, as well as different implications for interventions with regard to the supervisory triad. The authors examine the difference…

  7. Process Simulation of Complex Biological Pathways in Physical Reactive Space and Reformulated for Massively Parallel Computing Platforms.

    PubMed

    Ganesan, Narayan; Li, Jie; Sharma, Vishakha; Jiang, Hanyu; Compagnoni, Adriana

    2016-01-01

    Biological systems encompass complexity that far surpasses many artificial systems. Modeling and simulation of large and complex biochemical pathways is a computationally intensive challenge. Traditional tools, such as ordinary differential equations, partial differential equations, stochastic master equations, and Gillespie type methods, are all limited either by their modeling fidelity or computational efficiency or both. In this work, we present a scalable computational framework based on modeling biochemical reactions in explicit 3D space, that is suitable for studying the behavior of large and complex biological pathways. The framework is designed to exploit parallelism and scalability offered by commodity massively parallel processors such as the graphics processing units (GPUs) and other parallel computing platforms. The reaction modeling in 3D space is aimed at enhancing the realism of the model compared to traditional modeling tools and framework. We introduce the Parallel Select algorithm that is key to breaking the sequential bottleneck limiting the performance of most other tools designed to study biochemical interactions. The algorithm is designed to be computationally tractable, handle hundreds of interacting chemical species and millions of independent agents by considering all-particle interactions within the system. We also present an implementation of the framework on the popular graphics processing units and apply it to the simulation study of JAK-STAT Signal Transduction Pathway. The computational framework will offer a deeper insight into various biological processes within the cell and help us observe key events as they unfold in space and time. This will advance the current state-of-the-art in simulation study of large scale biological systems and also enable the realistic simulation study of macro-biological cultures, where inter-cellular interactions are prevalent.

  8. Parallel pulse processing and data acquisition for high speed, low error flow cytometry

    DOEpatents

    Engh, G.J. van den; Stokdijk, W.

    1992-09-22

    A digitally synchronized parallel pulse processing and data acquisition system for a flow cytometer has multiple parallel input channels with independent pulse digitization and FIFO storage buffer. A trigger circuit controls the pulse digitization on all channels. After an event has been stored in each FIFO, a bus controller moves the oldest entry from each FIFO buffer onto a common data bus. The trigger circuit generates an ID number for each FIFO entry, which is checked by an error detection circuit. The system has high speed and low error rate. 17 figs.

  9. Parallel pulse processing and data acquisition for high speed, low error flow cytometry

    DOEpatents

    van den Engh, Gerrit J.; Stokdijk, Willem

    1992-01-01

    A digitally synchronized parallel pulse processing and data acquisition system for a flow cytometer has multiple parallel input channels with independent pulse digitization and FIFO storage buffer. A trigger circuit controls the pulse digitization on all channels. After an event has been stored in each FIFO, a bus controller moves the oldest entry from each FIFO buffer onto a common data bus. The trigger circuit generates an ID number for each FIFO entry, which is checked by an error detection circuit. The system has high speed and low error rate.

  10. Big Data GPU-Driven Parallel Processing Spatial and Spatio-Temporal Clustering Algorithms

    NASA Astrophysics Data System (ADS)

    Konstantaras, Antonios; Skounakis, Emmanouil; Kilty, James-Alexander; Frantzeskakis, Theofanis; Maravelakis, Emmanuel

    2016-04-01

    Advances in graphics processing units' technology towards encompassing parallel architectures [1], comprised of thousands of cores and multiples of parallel threads, provide the foundation in terms of hardware for the rapid processing of various parallel applications regarding seismic big data analysis. Seismic data are normally stored as collections of vectors in massive matrices, growing rapidly in size as wider areas are covered, denser recording networks are being established and decades of data are being compiled together [2]. Yet, many processes regarding seismic data analysis are performed on each seismic event independently or as distinct tiles [3] of specific grouped seismic events within a much larger data set. Such processes, independent of one another can be performed in parallel narrowing down processing times drastically [1,3]. This research work presents the development and implementation of three parallel processing algorithms using Cuda C [4] for the investigation of potentially distinct seismic regions [5,6] present in the vicinity of the southern Hellenic seismic arc. The algorithms, programmed and executed in parallel comparatively, are the: fuzzy k-means clustering with expert knowledge [7] in assigning overall clusters' number; density-based clustering [8]; and a selves-developed spatio-temporal clustering algorithm encompassing expert [9] and empirical knowledge [10] for the specific area under investigation. Indexing terms: GPU parallel programming, Cuda C, heterogeneous processing, distinct seismic regions, parallel clustering algorithms, spatio-temporal clustering References [1] Kirk, D. and Hwu, W.: 'Programming massively parallel processors - A hands-on approach', 2nd Edition, Morgan Kaufman Publisher, 2013 [2] Konstantaras, A., Valianatos, F., Varley, M.R. and Makris, J.P.: 'Soft-Computing Modelling of Seismicity in the Southern Hellenic Arc', Geoscience and Remote Sensing Letters, vol. 5 (3), pp. 323-327, 2008 [3] Papadakis, S. and

  11. mHealthMon: toward energy-efficient and distributed mobile health monitoring using parallel offloading.

    PubMed

    Ahnn, Jong Hoon; Potkonjak, Miodrag

    2013-10-01

    Although mobile health monitoring where mobile sensors continuously gather, process, and update sensor readings (e.g. vital signals) from patient's sensors is emerging, little effort has been investigated in an energy-efficient management of sensor information gathering and processing. Mobile health monitoring with the focus of energy consumption may instead be holistically analyzed and systematically designed as a global solution to optimization subproblems. This paper presents an attempt to decompose the very complex mobile health monitoring system whose layer in the system corresponds to decomposed subproblems, and interfaces between them are quantified as functions of the optimization variables in order to orchestrate the subproblems. We propose a distributed and energy-saving mobile health platform, called mHealthMon where mobile users publish/access sensor data via a cloud computing-based distributed P2P overlay network. The key objective is to satisfy the mobile health monitoring application's quality of service requirements by modeling each subsystem: mobile clients with medical sensors, wireless network medium, and distributed cloud services. By simulations based on experimental data, we present the proposed system can achieve up to 10.1 times more energy-efficient and 20.2 times faster compared to a standalone mobile health monitoring application, in various mobile health monitoring scenarios applying a realistic mobility model. PMID:23897403

  12. Toward energy-efficient and distributed mobile health monitoring using parallel offloading.

    PubMed

    Ahnn, Jong Hoon; Potkonjak, Miodrag

    2013-01-01

    Although mobile health monitoring where mobile sensors continuously gather, process, and update sensor readings (e.g. vital signals) from patient's sensors is emerging, little effort has been investigated in an energy-efficient management of sensor information gathering and processing. Mobile health monitoring with the focus of energy consumption may instead be holistically analyzed and systematically designed as a global solution to optimization subproblems. We propose a distributed and energy-saving mobile health platform, called mHealthMon where mobile users publish/access sensor data via a cloud computing-based distributed P2P overlay network. The key objective is to satisfy the mobile health monitoring application's quality of service requirements by modeling each subsystem: mobile clients with medical sensors, wireless network medium, and distributed cloud services. By simulations based on experimental data, we present the proposed system can achieve up to 10.1 times more energy-efficient and 20.2 times faster compared to a standalone mobile health monitoring application, in various mobile health monitoring scenarios applying a realistic mobility model. PMID:24111420

  13. Toward energy-efficient and distributed mobile health monitoring using parallel offloading.

    PubMed

    Ahnn, Jong Hoon; Potkonjak, Miodrag

    2013-01-01

    Although mobile health monitoring where mobile sensors continuously gather, process, and update sensor readings (e.g. vital signals) from patient's sensors is emerging, little effort has been investigated in an energy-efficient management of sensor information gathering and processing. Mobile health monitoring with the focus of energy consumption may instead be holistically analyzed and systematically designed as a global solution to optimization subproblems. We propose a distributed and energy-saving mobile health platform, called mHealthMon where mobile users publish/access sensor data via a cloud computing-based distributed P2P overlay network. The key objective is to satisfy the mobile health monitoring application's quality of service requirements by modeling each subsystem: mobile clients with medical sensors, wireless network medium, and distributed cloud services. By simulations based on experimental data, we present the proposed system can achieve up to 10.1 times more energy-efficient and 20.2 times faster compared to a standalone mobile health monitoring application, in various mobile health monitoring scenarios applying a realistic mobility model.

  14. mHealthMon: toward energy-efficient and distributed mobile health monitoring using parallel offloading.

    PubMed

    Ahnn, Jong Hoon; Potkonjak, Miodrag

    2013-10-01

    Although mobile health monitoring where mobile sensors continuously gather, process, and update sensor readings (e.g. vital signals) from patient's sensors is emerging, little effort has been investigated in an energy-efficient management of sensor information gathering and processing. Mobile health monitoring with the focus of energy consumption may instead be holistically analyzed and systematically designed as a global solution to optimization subproblems. This paper presents an attempt to decompose the very complex mobile health monitoring system whose layer in the system corresponds to decomposed subproblems, and interfaces between them are quantified as functions of the optimization variables in order to orchestrate the subproblems. We propose a distributed and energy-saving mobile health platform, called mHealthMon where mobile users publish/access sensor data via a cloud computing-based distributed P2P overlay network. The key objective is to satisfy the mobile health monitoring application's quality of service requirements by modeling each subsystem: mobile clients with medical sensors, wireless network medium, and distributed cloud services. By simulations based on experimental data, we present the proposed system can achieve up to 10.1 times more energy-efficient and 20.2 times faster compared to a standalone mobile health monitoring application, in various mobile health monitoring scenarios applying a realistic mobility model.

  15. Hippocampal-prefrontal dynamics in spatial working memory: interactions and independent parallel processing.

    PubMed

    Churchwell, John C; Kesner, Raymond P

    2011-12-01

    Memory processes may be independent, compete, operate in parallel, or interact. In accordance with this view, behavioral studies suggest that the hippocampus (HPC) and prefrontal cortex (PFC) may act as an integrated circuit during performance of tasks that require working memory over longer delays, whereas during short delays the HPC and PFC may operate in parallel or have completely dissociable functions. In the present investigation we tested rats in a spatial delayed non-match to sample working memory task using short and long time delays to evaluate the hypothesis that intermediate CA1 region of the HPC (iCA1) and medial PFC (mPFC) interact and operate in parallel under different temporal working memory constraints. In order to assess the functional role of these structures, we used an inactivation strategy in which each subject received bilateral chronic cannula implantation of the iCA1 and mPFC, allowing us to perform bilateral, contralateral, ipsilateral, and combined bilateral inactivation of structures and structure pairs within each subject. This novel approach allowed us to test for circuit-level systems interactions, as well as independent parallel processing, while we simultaneously parametrically manipulated the temporal dimension of the task. The current results suggest that, at longer delays, iCA1 and mPFC interact to coordinate retrospective and prospective memory processes in anticipation of obtaining a remote goal, whereas at short delays either structure may independently represent spatial information sufficient to successfully complete the task. PMID:21839780

  16. A multi-satellite orbit determination problem in a parallel processing environment

    NASA Technical Reports Server (NTRS)

    Deakyne, M. S.; Anderle, R. J.

    1988-01-01

    The Engineering Orbit Analysis Unit at GE Valley Forge used an Intel Hypercube Parallel Processor to investigate the performance and gain experience of parallel processors with a multi-satellite orbit determination problem. A general study was selected in which major blocks of computation for the multi-satellite orbit computations were used as units to be assigned to the various processors on the Hypercube. Problems encountered or successes achieved in addressing the orbit determination problem would be more likely to be transferable to other parallel processors. The prime objective was to study the algorithm to allow processing of observations later in time than those employed in the state update. Expertise in ephemeris determination was exploited in addressing these problems and the facility used to bring a realism to the study which would highlight the problems which may not otherwise be anticipated. Secondary objectives were to gain experience of a non-trivial problem in a parallel processor environment, to explore the necessary interplay of serial and parallel sections of the algorithm in terms of timing studies, to explore the granularity (coarse vs. fine grain) to discover the granularity limit above which there would be a risk of starvation where the majority of nodes would be idle or under the limit where the overhead associated with splitting the problem may require more work and communication time than is useful.

  17. Parallel processing in a host plus multiple array processor system for radar

    NASA Technical Reports Server (NTRS)

    Barkan, B. Z.

    1983-01-01

    Host plus multiple array processor architecture is demonstrated to yield a modular, fast, and cost-effective system for radar processing. Software methodology for programming such a system is developed. Parallel processing with pipelined data flow among the host, array processors, and discs is implemented. Theoretical analysis of performance is made and experimentally verified. The broad class of problems to which the architecture and methodology can be applied is indicated.

  18. An automated workflow for parallel processing of large multiview SPIM recordings

    PubMed Central

    Schmied, Christopher; Steinbach, Peter; Pietzsch, Tobias; Preibisch, Stephan; Tomancak, Pavel

    2016-01-01

    Summary: Selective Plane Illumination Microscopy (SPIM) allows to image developing organisms in 3D at unprecedented temporal resolution over long periods of time. The resulting massive amounts of raw image data requires extensive processing interactively via dedicated graphical user interface (GUI) applications. The consecutive processing steps can be easily automated and the individual time points can be processed independently, which lends itself to trivial parallelization on a high performance computing (HPC) cluster. Here, we introduce an automated workflow for processing large multiview, multichannel, multiillumination time-lapse SPIM data on a single workstation or in parallel on a HPC cluster. The pipeline relies on snakemake to resolve dependencies among consecutive processing steps and can be easily adapted to any cluster environment for processing SPIM data in a fraction of the time required to collect it. Availability and implementation: The code is distributed free and open source under the MIT license http://opensource.org/licenses/MIT. The source code can be downloaded from github: https://github.com/mpicbg-scicomp/snakemake-workflows. Documentation can be found here: http://fiji.sc/Automated_workflow_for_parallel_Multiview_Reconstruction. Contact: schmied@mpi-cbg.de Supplementary information: Supplementary data are available at Bioinformatics online. PMID:26628585

  19. Highly efficient and exact method for parallelization of grid-based algorithms and its implementation in DelPhi

    PubMed Central

    Li, Chuan; Li, Lin; Zhang, Jie; Alexov, Emil

    2012-01-01

    The Gauss-Seidel method is a standard iterative numerical method widely used to solve a system of equations and, in general, is more efficient comparing to other iterative methods, such as the Jacobi method. However, standard implementation of the Gauss-Seidel method restricts its utilization in parallel computing due to its requirement of using updated neighboring values (i.e., in current iteration) as soon as they are available. Here we report an efficient and exact (not requiring assumptions) method to parallelize iterations and to reduce the computational time as a linear/nearly linear function of the number of CPUs. In contrast to other existing solutions, our method does not require any assumptions and is equally applicable for solving linear and nonlinear equations. This approach is implemented in the DelPhi program, which is a finite difference Poisson-Boltzmann equation solver to model electrostatics in molecular biology. This development makes the iterative procedure on obtaining the electrostatic potential distribution in the parallelized DelPhi several folds faster than that in the serial code. Further we demonstrate the advantages of the new parallelized DelPhi by computing the electrostatic potential and the corresponding energies of large supramolecular structures. PMID:22674480

  20. Massively parallel per-pixel-based zerotree processing architecture for real-time video compression

    NASA Astrophysics Data System (ADS)

    Alagoda, Geoffrey; Rassau, Alexander M.; Eshraghian, Kamran

    2001-11-01

    In the span of a few years, mobile multimedia communication has rapidly become a significant area of research and development constantly challenging boundaries on a variety of technological fronts. Video compression, a fundamental component for most mobile multimedia applications, generally places heavy demands in terms of the required processing capacity. Hardware implementations of typical modern hybrid codecs require realisation of components such as motion compensation, wavelet transform, quantisation, zerotree coding and arithmetic coding in real-time. While the implementation of such codecs using a fast generic processor is possible, undesirable trade-offs in terms of power consumption and speed must generally be made. The improvement in power consumption that is achievable through the use of a slow-clocked massively parallel processing environment, while maintaining real-time processing speeds, should thus not be overlooked. An architecture to realise such a massively parallel solution for a zerotree entropy coder is, therefore, presented in this paper.

  1. Lossy hyperspectral image compression on a graphics processing unit: parallelization strategy and performance evaluation

    NASA Astrophysics Data System (ADS)

    Santos, Lucana; Magli, Enrico; Vitulli, Raffaele; Núñez, Antonio; López, José F.; Sarmiento, Roberto

    2013-01-01

    There is an intense necessity for the development of new hardware architectures for the implementation of algorithms for hyperspectral image compression on board satellites. Graphics processing units (GPUs) represent a very attractive opportunity, offering the possibility to dramatically increase the computation speed in applications that are data and task parallel. An algorithm for the lossy compression of hyperspectral images is implemented on a GPU using Nvidia computer unified device architecture (CUDA) parallel computing architecture. The parallelization strategy is explained, with emphasis on the entropy coding and bit packing phases, for which a more sophisticated strategy is necessary due to the existing data dependencies. Experimental results are obtained by comparing the performance of the GPU implementation with a single-threaded CPU implementation, showing high speedups of up to 15.41. A profiling of the algorithm is provided, demonstrating the high performance of the designed parallel entropy coding phase. The accuracy of the GPU implementation is presented, as well as the effect of the configuration parameters on performance. The convenience of using GPUs for on-board processing is demonstrated, and solutions to the potential difficulties encountered when accelerating hyperspectral compression algorithms are proposed, if space-qualified GPUs become a reality in the near future.

  2. ISP: an optimal out-of-core image-set processing streaming architecture for parallel heterogeneous systems.

    PubMed

    Ha, Linh Khanh; Krüger, Jens; Dihl Comba, João Luiz; Silva, Cláudio T; Joshi, Sarang

    2012-06-01

    Image population analysis is the class of statistical methods that plays a central role in understanding the development, evolution, and disease of a population. However, these techniques often require excessive computational power and memory that are compounded with a large number of volumetric inputs. Restricted access to supercomputing power limits its influence in general research and practical applications. In this paper we introduce ISP, an Image-Set Processing streaming framework that harnesses the processing power of commodity heterogeneous CPU/GPU systems and attempts to solve this computational problem. In ISP, we introduce specially designed streaming algorithms and data structures that provide an optimal solution for out-of-core multiimage processing problems both in terms of memory usage and computational efficiency. ISP makes use of the asynchronous execution mechanism supported by parallel heterogeneous systems to efficiently hide the inherent latency of the processing pipeline of out-of-core approaches. Consequently, with computationally intensive problems, the ISP out-of-core solution can achieve the same performance as the in-core solution. We demonstrate the efficiency of the ISP framework on synthetic and real datasets. PMID:22291156

  3. ISP: an optimal out-of-core image-set processing streaming architecture for parallel heterogeneous systems.

    PubMed

    Ha, Linh Khanh; Krüger, Jens; Dihl Comba, João Luiz; Silva, Cláudio T; Joshi, Sarang

    2012-06-01

    Image population analysis is the class of statistical methods that plays a central role in understanding the development, evolution, and disease of a population. However, these techniques often require excessive computational power and memory that are compounded with a large number of volumetric inputs. Restricted access to supercomputing power limits its influence in general research and practical applications. In this paper we introduce ISP, an Image-Set Processing streaming framework that harnesses the processing power of commodity heterogeneous CPU/GPU systems and attempts to solve this computational problem. In ISP, we introduce specially designed streaming algorithms and data structures that provide an optimal solution for out-of-core multiimage processing problems both in terms of memory usage and computational efficiency. ISP makes use of the asynchronous execution mechanism supported by parallel heterogeneous systems to efficiently hide the inherent latency of the processing pipeline of out-of-core approaches. Consequently, with computationally intensive problems, the ISP out-of-core solution can achieve the same performance as the in-core solution. We demonstrate the efficiency of the ISP framework on synthetic and real datasets.

  4. Efficient audio signal processing for embedded systems

    NASA Astrophysics Data System (ADS)

    Chiu, Leung Kin

    As mobile platforms continue to pack on more computational power, electronics manufacturers start to differentiate their products by enhancing the audio features. However, consumers also demand smaller devices that could operate for longer time, hence imposing design constraints. In this research, we investigate two design strategies that would allow us to efficiently process audio signals on embedded systems such as mobile phones and portable electronics. In the first strategy, we exploit properties of the human auditory system to process audio signals. We designed a sound enhancement algorithm to make piezoelectric loudspeakers sound ”richer" and "fuller." Piezoelectric speakers have a small form factor but exhibit poor response in the low-frequency region. In the algorithm, we combine psychoacoustic bass extension and dynamic range compression to improve the perceived bass coming out from the tiny speakers. We also developed an audio energy reduction algorithm for loudspeaker power management. The perceptually transparent algorithm extends the battery life of mobile devices and prevents thermal damage in speakers. This method is similar to audio compression algorithms, which encode audio signals in such a ways that the compression artifacts are not easily perceivable. Instead of reducing the storage space, however, we suppress the audio contents that are below the hearing threshold, therefore reducing the signal energy. In the second strategy, we use low-power analog circuits to process the signal before digitizing it. We designed an analog front-end for sound detection and implemented it on a field programmable analog array (FPAA). The system is an example of an analog-to-information converter. The sound classifier front-end can be used in a wide range of applications because programmable floating-gate transistors are employed to store classifier weights. Moreover, we incorporated a feature selection algorithm to simplify the analog front-end. A machine

  5. An FPGA-based High Speed Parallel Signal Processing System for Adaptive Optics Testbed

    NASA Astrophysics Data System (ADS)

    Kim, H.; Choi, Y.; Yang, Y.

    In this paper a state-of-the-art FPGA (Field Programmable Gate Array) based high speed parallel signal processing system (SPS) for adaptive optics (AO) testbed with 1 kHz wavefront error (WFE) correction frequency is reported. The AO system consists of Shack-Hartmann sensor (SHS) and deformable mirror (DM), tip-tilt sensor (TTS), tip-tilt mirror (TTM) and an FPGA-based high performance SPS to correct wavefront aberrations. The SHS is composed of 400 subapertures and the DM 277 actuators with Fried geometry, requiring high speed parallel computing capability SPS. In this study, the target WFE correction speed is 1 kHz; therefore, it requires massive parallel computing capabilities as well as strict hard real time constraints on measurements from sensors, matrix computation latency for correction algorithms, and output of control signals for actuators. In order to meet them, an FPGA based real-time SPS with parallel computing capabilities is proposed. In particular, the SPS is made up of a National Instrument's (NI's) real time computer and five FPGA boards based on state-of-the-art Xilinx Kintex 7 FPGA. Programming is done with NI's LabView environment, providing flexibility when applying different algorithms for WFE correction. It also facilitates faster programming and debugging environment as compared to conventional ones. One of the five FPGA's is assigned to measure TTS and calculate control signals for TTM, while the rest four are used to receive SHS signal, calculate slops for each subaperture and correction signal for DM. With this parallel processing capabilities of the SPS the overall closed-loop WFE correction speed of 1 kHz has been achieved. System requirements, architecture and implementation issues are described; furthermore, experimental results are also given.

  6. Parallel Processing of Big Point Clouds Using Z-Order Partitioning

    NASA Astrophysics Data System (ADS)

    Alis, C.; Boehm, J.; Liu, K.

    2016-06-01

    As laser scanning technology improves and costs are coming down, the amount of point cloud data being generated can be prohibitively difficult and expensive to process on a single machine. This data explosion is not only limited to point cloud data. Voluminous amounts of high-dimensionality and quickly accumulating data, collectively known as Big Data, such as those generated by social media, Internet of Things devices and commercial transactions, are becoming more prevalent as well. New computing paradigms and frameworks are being developed to efficiently handle the processing of Big Data, many of which utilize a compute cluster composed of several commodity grade machines to process chunks of data in parallel. A central concept in many of these frameworks is data locality. By its nature, Big Data is large enough that the entire dataset would not fit on the memory and hard drives of a single node hence replicating the entire dataset to each worker node is impractical. The data must then be partitioned across worker nodes in a manner that minimises data transfer across the network. This is a challenge for point cloud data because there exist different ways to partition data and they may require data transfer. We propose a partitioning based on Z-order which is a form of locality-sensitive hashing. The Z-order or Morton code is computed by dividing each dimension to form a grid then interleaving the binary representation of each dimension. For example, the Z-order code for the grid square with coordinates (x = 1 = 012, y = 3 = 112) is 10112 = 11. The number of points in each partition is controlled by the number of bits per dimension: the more bits, the fewer the points. The number of bits per dimension also controls the level of detail with more bits yielding finer partitioning. We present this partitioning method by implementing it on Apache Spark and investigating how different parameters affect the accuracy and running time of the k nearest neighbour algorithm

  7. Serial processing in reading aloud: no challenge for a parallel model.

    PubMed

    Zorzi, M

    2000-04-01

    K. Rastle and M. Coltheart (1999) challenged parallel models of reading by showing that the cost of irregularity in low-frequency exception words was modulated by the position of the irregularity in the word. This position-of-irregularity effect was taken as strong evidence of serial processing in reading. This article refutes Rastle and Coltheart's theoretical conclusions in 3 ways: First, a parallel model, the connectionist dual process model (M. Zorzi, G. Houghton, & B. Butterworth, 1998b), produces a position-of-irregularity effect. Second, the supposed serial effect can be reduced to a position-specific grapheme-phoneme consistency effect. Third, the position-of-irregularity effect vanishes when the experimental data are reanalyzed using grapheme-phoneme consistency as the covariate. This demonstration has broader implications for studies aiming at adjudicating between models: Strong inferences should be avoided until the computational models are actually tested.

  8. A structured command history for UNIX using a parallel distributed processing model

    SciTech Connect

    Uejio, J.Y.

    1989-03-01

    This thesis investigates the use of a structured history to assist users in recalling previously entered complex UNIX commands. A structured history is a database of commands that were previously entered. Two models are presented: the first model uses a conventional database and the second model uses a parallel distributed processing system. The conventional database system can recall commands by pattern matching based on command name, pattern matching on command options, frequency of use, and relative time. A simple prototype, created using the Emacs environment, was useful in recalling previously entered UNIX commands. The parallel distributed processing system stores UNIX commands by decomposing them into two character sequences called bigrams. A prototype implementation used a two layer network, in which each unit represents a bigram. The implementation showed features such as spelling correction and associated command recall. The ability to recall a list of commands satisfying a particular criteria is among the advantages of a structured history. 19 refs., 8 figs., 1 tab.

  9. Lower upper cycle independent implicit parallel processing algorithm for the compressible Navier-Stokes equations

    NASA Astrophysics Data System (ADS)

    Ghizawi, Nidal Awni

    Computational Fluid Dynamics problems of engineering interest are among the most demanding scientific problems in terms of the massive computational resources they require. Only parallel architecture computers offer the promise of providing orders of magnitude greater computational power. A common feature of the currently available implicit flow solvers for the compressible Navier-Stokes equations is that the solution for a multi-dimensional problem is obtained by the solution of a set of dependent problems which must be computed in series. In this study, a lower upper cycle independent (LUCI) implicit parallel processing algorithm for solving the compressible Navier-Stokes equations is proposed. A characteristic feature of this algorithm is that the solution for a multi-dimensional problem is obtained by the superposition of the solution of a set of independent problems which, therefore, enhances its parallel processing functionality. The accuracy and stability of this algorithm are carefully analyzed and compared with those of other algorithms. Flow computations using the LUCI algorithm are performed for two test cases which show the symmetry preserving property of this algorithm and demonstrate its accuracy. Through employing the principle of pseudo-parallelism, effects of domain decomposition on the stability and convergence of the LUCI and the Symmetric Successive Over-Relaxation (SSOR) schemes (representative of cycle dependent implicit schemes) are analyzed and quantified. Parallel implementation details of the LUCI (in two VERSIONS: I and II) and the SSOR (in VERSION I) schemes using the standard (portable) Message Passing Interface (MPI) on two computational platforms are given. These platforms are: Lewis Advanced Cluster Environment (LACE) which is an example of Network of Workstations (NOWs), and the Ohio Supercomputer CRAY T3D massive parallel computing environment. Parallel performance results indicate that VERSION I of the LUCI scheme is superior to

  10. Eighth SIAM conference on parallel processing for scientific computing: Final program and abstracts

    SciTech Connect

    1997-12-31

    This SIAM conference is the premier forum for developments in parallel numerical algorithms, a field that has seen very lively and fruitful developments over the past decade, and whose health is still robust. Themes for this conference were: combinatorial optimization; data-parallel languages; large-scale parallel applications; message-passing; molecular modeling; parallel I/O; parallel libraries; parallel software tools; parallel compilers; particle simulations; problem-solving environments; and sparse matrix computations.

  11. Queueing Network Models for Parallel Processing of Task Systems: an Operational Approach

    NASA Technical Reports Server (NTRS)

    Mak, Victor W. K.

    1986-01-01

    Computer performance modeling of possibly complex computations running on highly concurrent systems is considered. Earlier works in this area either dealt with a very simple program structure or resulted in methods with exponential complexity. An efficient procedure is developed to compute the performance measures for series-parallel-reducible task systems using queueing network models. The procedure is based on the concept of hierarchical decomposition and a new operational approach. Numerical results for three test cases are presented and compared to those of simulations.

  12. Initial operating capability for the hypercluster parallel-processing test bed

    NASA Technical Reports Server (NTRS)

    Cole, Gary L.; Blech, Richard A.; Quealy, Angela

    1989-01-01

    The NASA Lewis Research Center is investigating the benefits of parallel processing to applications in computational fluid and structural mechanics. To aid this investigation, NASA Lewis is developing the Hypercluster, a multi-architecture, parallel-processing test bed. The initial operating capability (IOC) being developed for the Hypercluster is described. The IOC will provide a user with a programming/operating environment that is interactive, responsive, and easy to use. The IOC effort includes the development of the Hypercluster Operating System (HYCLOPS). HYCLOPS runs in conjunction with a vendor-supplied disk operating system on a Front-End Processor (FEP) to provide interactive, run-time operations such as program loading, execution, memory editing, and data retrieval. Run-time libraries, that augment the FEP FORTRAN libraries, are being developed to support parallel and vector processing on the Hypercluster. Special utilities are being provided to enable passage of information about application programs and their mapping to the operating system. Communications between the FEP and the Hypercluster are being handled by dedicated processors, each running a Message-Passing Kernel, (MPK). A shared-memory interface allows rapid data exchange between HYCLOPS and the communications processors. Input/output handlers are built into the HYCLOPS-MPK interface, eliminating the need for the user to supply separate I/O support programs on the FEP.

  13. Parallel particle swarm optimization on a graphics processing unit with application to trajectory optimization

    NASA Astrophysics Data System (ADS)

    Wu, Q.; Xiong, F.; Wang, F.; Xiong, Y.

    2016-10-01

    In order to reduce the computational time, a fully parallel implementation of the particle swarm optimization (PSO) algorithm on a graphics processing unit (GPU) is presented. Instead of being executed on the central processing unit (CPU) sequentially, PSO is executed in parallel via the GPU on the compute unified device architecture (CUDA) platform. The processes of fitness evaluation, updating of velocity and position of all particles are all parallelized and introduced in detail. Comparative studies on the optimization of four benchmark functions and a trajectory optimization problem are conducted by running PSO on the GPU (GPU-PSO) and CPU (CPU-PSO). The impact of design dimension, number of particles and size of the thread-block in the GPU and their interactions on the computational time is investigated. The results show that the computational time of the developed GPU-PSO is much shorter than that of CPU-PSO, with comparable accuracy, which demonstrates the remarkable speed-up capability of GPU-PSO.

  14. Understanding decimal proportions: discrete representations, parallel access, and privileged processing of zero.

    PubMed

    Varma, Sashank; Karl, Stacy R

    2013-05-01

    Much of the research on mathematical cognition has focused on the numbers 1, 2, 3, 4, 5, 6, 7, 8, and 9, with considerably less attention paid to more abstract number classes. The current research investigated how people understand decimal proportions--rational numbers between 0 and 1 expressed in the place-value symbol system. The results demonstrate that proportions are represented as discrete structures and processed in parallel. There was a semantic interference effect: When understanding a proportion expression (e.g., "0.29"), both the correct proportion referent (e.g., 0.29) and the incorrect natural number referent (e.g., 29) corresponding to the visually similar natural number expression (e.g., "29") are accessed in parallel, and when these referents lead to conflicting judgments, performance slows. There was also a syntactic interference effect, generalizing the unit-decade compatibility effect for natural numbers: When comparing two proportions, their tenths and hundredths components are processed in parallel, and when the different components lead to conflicting judgments, performance slows. The results also reveal that zero decimals--proportions ending in zero--serve multiple cognitive functions, including eliminating semantic interference and speeding processing. The current research also extends the distance, semantic congruence, and SNARC effects from natural numbers to decimal proportions. These findings inform how people understand the place-value symbol system, and the mental implementation of mathematical symbol systems more generally.

  15. A systolic array parallelizing compiler

    SciTech Connect

    Tseng, P.S. )

    1990-01-01

    This book presents a completely new approach to the problem of systolic array parallelizing compiler. It describes the AL parallelizing compiler for the Warp systolic array, the first working systolic array parallelizing compiler which can generate efficient parallel code for complete LINPACK routines. This book begins by analyzing the architectural strength of the Warp systolic array. It proposes a model for mapping programs onto the machine and introduces the notion of data relations for optimizing the program mapping. Also presented are successful applications of the AL compiler in matrix computation and image processing. A complete listing of the source program and compiler-generated parallel code are given to clarify the overall picture of the compiler. The book concludes that systolic array parallelizing compiler can produce efficient parallel code, almost identical to what the user would have written by hand.

  16. GWM-VI: groundwater management with parallel processing for multiple MODFLOW versions

    USGS Publications Warehouse

    Banta, Edward R.; Ahlfeld, David P.

    2013-01-01

    Groundwater Management–Version Independent (GWM–VI) is a new version of the Groundwater Management Process of MODFLOW. The Groundwater Management Process couples groundwater-flow simulation with a capability to optimize stresses on the simulated aquifer based on an objective function and constraints imposed on stresses and aquifer state. GWM–VI extends prior versions of Groundwater Management in two significant ways—(1) it can be used with any version of MODFLOW that meets certain requirements on input and output, and (2) it is structured to allow parallel processing of the repeated runs of the MODFLOW model that are required to solve the optimization problem. GWM–VI uses the same input structure for files that describe the management problem as that used by prior versions of Groundwater Management. GWM–VI requires only minor changes to the input files used by the MODFLOW model. GWM–VI uses the Joint Universal Parameter IdenTification and Evaluation of Reliability Application Programming Interface (JUPITER-API) to implement both version independence and parallel processing. GWM–VI communicates with the MODFLOW model by manipulating certain input files and interpreting results from the MODFLOW listing file and binary output files. Nearly all capabilities of prior versions of Groundwater Management are available in GWM–VI. GWM–VI has been tested with MODFLOW-2005, MODFLOW-NWT (a Newton formulation for MODFLOW-2005), MF2005-FMP2 (the Farm Process for MODFLOW-2005), SEAWAT, and CFP (Conduit Flow Process for MODFLOW-2005). This report provides sample problems that demonstrate a range of applications of GWM–VI and the directory structure and input information required to use the parallel-processing capability.

  17. Library Preparation and Multiplex Capture for Massive Parallel Sequencing Applications Made Efficient and Easy

    PubMed Central

    Neiman, Mårten; Sundling, Simon; Grönberg, Henrik; Hall, Per; Czene, Kamila

    2012-01-01

    During the recent years, rapid development of sequencing technologies and a competitive market has enabled researchers to perform massive sequencing projects at a reasonable cost. As the price for the actual sequencing reactions drops, enabling more samples to be sequenced, the relative price for preparing libraries gets larger and the practical laboratory work becomes complex and tedious. We present a cost-effective strategy for simplified library preparation compatible with both whole genome- and targeted sequencing experiments. An optimized enzyme composition and reaction buffer reduces the number of required clean-up steps and allows for usage of bulk enzymes which makes the whole process cheap, efficient and simple. We also present a two-tagging strategy, which allows for multiplex sequencing of targeted regions. To prove our concept, we have prepared libraries for low-pass sequencing from 100 ng DNA, performed 2-, 4- and 8-plex exome capture and a 96-plex capture of a 500 kb region. In all samples we see a high concordance (>99.4%) of SNP calls when comparing to commercially available SNP-chip platforms. PMID:23139805

  18. Real-time processing of radar return on a parallel computer

    NASA Technical Reports Server (NTRS)

    Aalfs, David D.

    1992-01-01

    NASA is working with the FAA to demonstrate the feasibility of pulse Doppler radar as a candidate airborne sensor to detect low altitude windshears. The need to provide the pilot with timely information about possible hazards has motivated a demand for real-time processing of a radar return. Investigated here is parallel processing as a means of accommodating the high data rates required. A PC based parallel computer, called the transputer, is used to investigate issues in real time concurrent processing of radar signals. A transputer network is made up of an array of single instruction stream processors that can be networked in a variety of ways. They are easily reconfigured and software development is largely independent of the particular network topology. The performance of the transputer is evaluated in light of the computational requirements. A number of algorithms have been implemented on the transputers in OCCAM, a language specially designed for parallel processing. These include signal processing algorithms such as the Fast Fourier Transform (FFT), pulse-pair, and autoregressive modelling, as well as routing software to support concurrency. The most computationally intensive task is estimating the spectrum. Two approaches have been taken on this problem, the first and most conventional of which is to use the FFT. By using table look-ups for the basis function and other optimizing techniques, an algorithm has been developed that is sufficient for real time. The other approach is to model the signal as an autoregressive process and estimate the spectrum based on the model coefficients. This technique is attractive because it does not suffer from the spectral leakage problem inherent in the FFT. Benchmark tests indicate that autoregressive modeling is feasible in real time.

  19. Scheduling Jobs with Variable Job Processing Times on Unrelated Parallel Machines

    PubMed Central

    Zhang, Guang-Qian; Wang, Jian-Jun; Liu, Ya-Jing

    2014-01-01

    m unrelated parallel machines scheduling problems with variable job processing times are considered, where the processing time of a job is a function of its position in a sequence, its starting time, and its resource allocation. The objective is to determine the optimal resource allocation and the optimal schedule to minimize a total cost function that dependents on the total completion (waiting) time, the total machine load, the total absolute differences in completion (waiting) times on all machines, and total resource cost. If the number of machines is a given constant number, we propose a polynomial time algorithm to solve the problem. PMID:24982933

  20. Lamb wave propagation modelling and simulation using parallel processing architecture and graphical cards

    NASA Astrophysics Data System (ADS)

    Paćko, P.; Bielak, T.; Spencer, A. B.; Staszewski, W. J.; Uhl, T.; Worden, K.

    2012-07-01

    This paper demonstrates new parallel computation technology and an implementation for Lamb wave propagation modelling in complex structures. A graphical processing unit (GPU) and computer unified device architecture (CUDA), available in low-cost graphical cards in standard PCs, are used for Lamb wave propagation numerical simulations. The local interaction simulation approach (LISA) wave propagation algorithm has been implemented as an example. Other algorithms suitable for parallel discretization can also be used in practice. The method is illustrated using examples related to damage detection. The results demonstrate good accuracy and effective computational performance of very large models. The wave propagation modelling presented in the paper can be used in many practical applications of science and engineering.

  1. Development of Three-Dimensional Integration Technology for Highly Parallel Image-Processing Chip

    NASA Astrophysics Data System (ADS)

    Lee, Kang Wook; Nakamura, Tomonori; Sakuma, Katsuyuki; Park, Ki Tae; Shimazutsu, Hiroaki; Miyakawa, Nobuaki; Kim, Ki Yoon; Kurino, Hiroyuki; Koyanagi, Mitsumasa

    2000-04-01

    A new three-dimensional (3D) integration technology for realizing a highly parallel image-processing chip has been developed. Several LSI wafers are vertically stacked and glued to each other after thinning them using this new technology. This technology can be considered as both 3D LSI technology and wafer-scale 3D chip-on-chip packaging technology. The effective packaging density can be significantly increased by stacking the chips in a vertical direction. Several key techniques for this 3D integration have been developed. In this paper, we demonstrate the highly parallel image sensor chip with a 3D structure. The 3D image sensor test chip was fabricated using this new 3D integration technology and its basic performance was evaluated.

  2. Distributed Parallel Processing and Dynamic Load Balancing Techniques for Multidisciplinary High Speed Aircraft Design

    NASA Technical Reports Server (NTRS)

    Krasteva, Denitza T.

    1998-01-01

    Multidisciplinary design optimization (MDO) for large-scale engineering problems poses many challenges (e.g., the design of an efficient concurrent paradigm for global optimization based on disciplinary analyses, expensive computations over vast data sets, etc.) This work focuses on the application of distributed schemes for massively parallel architectures to MDO problems, as a tool for reducing computation time and solving larger problems. The specific problem considered here is configuration optimization of a high speed civil transport (HSCT), and the efficient parallelization of the embedded paradigm for reasonable design space identification. Two distributed dynamic load balancing techniques (random polling and global round robin with message combining) and two necessary termination detection schemes (global task count and token passing) were implemented and evaluated in terms of effectiveness and scalability to large problem sizes and a thousand processors. The effect of certain parameters on execution time was also inspected. Empirical results demonstrated stable performance and effectiveness for all schemes, and the parametric study showed that the selected algorithmic parameters have a negligible effect on performance.

  3. Parallel architecture for labeling, segmentation, and lexical processing in speech understanding

    SciTech Connect

    Bronson, E.C.; Siegel, L.J.

    1983-01-01

    Speech understanding is a complex task which requires extensive computation. To increase the processing speed, a speech understanding system is decomposed into tasks which can be performed by a series of distributed processing subsystems. An architecture to perform labeling, segmentation, and lexical processing is described. Using a parametric characterization of the speech signal, this system divides an utterance into labeled homogeneous regions. The system then performs dictionary lookups based on all probable labelings and segmentations in order to generate a complete set of word hypotheses. Using realistic assumptions from existing speech understanding systems, a statistical model of speech input, and simulations of the speech processing algorithms, the attributes of the parallel system to perform labeling, segmentation, and lexical processing for real-time speech understanding are derived. 36 references.

  4. Propagation of electromagnetic fields between non-parallel planes: a fully vectorial formulation and an efficient implementation.

    PubMed

    Zhang, Site; Asoubar, Daniel; Hellmann, Christian; Wyrowski, Frank

    2016-01-20

    The propagation of electromagnetic fields between non-parallel planes based on a spectrum-of-plane-wave analysis is discussed and formulations for an efficient numerical implementation are presented in detail. It is shown that with the help of interpolation techniques, the numerical implementation can be done with the standard uniform fast Fourier transform (FFT) of easy access. Different interpolation techniques are numerically examined, and it turns out that the use of cubic interpolation, together with the uniform FFT, brings both significantly increased computational efficiency and high simulation accuracy. Apart from the aspect of computational efficiency, all formulations in this work are generalized in a fully vectorial manner in comparison to previous works. PMID:26835928

  5. Propagation of electromagnetic fields between non-parallel planes: a fully vectorial formulation and an efficient implementation.

    PubMed

    Zhang, Site; Asoubar, Daniel; Hellmann, Christian; Wyrowski, Frank

    2016-01-20

    The propagation of electromagnetic fields between non-parallel planes based on a spectrum-of-plane-wave analysis is discussed and formulations for an efficient numerical implementation are presented in detail. It is shown that with the help of interpolation techniques, the numerical implementation can be done with the standard uniform fast Fourier transform (FFT) of easy access. Different interpolation techniques are numerically examined, and it turns out that the use of cubic interpolation, together with the uniform FFT, brings both significantly increased computational efficiency and high simulation accuracy. Apart from the aspect of computational efficiency, all formulations in this work are generalized in a fully vectorial manner in comparison to previous works.

  6. Improving efficiency of a global barrier operation in a parallel computer

    DOEpatents

    None

    2016-10-04

    Performing a global barrier operation in a parallel computer that includes compute nodes coupled for data communications, where each compute node executes tasks, with one task on each compute node designated as a master task, including: for each task on each compute node until all master tasks have joined a global barrier: determining whether the task is a master task; if the task is not a master task, joining a single local barrier; if the task is a master task, joining the global barrier and the single local barrier only after all other tasks on the compute node have joined the single local barrier.

  7. Massively parallel mathematical sieves

    SciTech Connect

    Montry, G.R.

    1989-01-01

    The Sieve of Eratosthenes is a well-known algorithm for finding all prime numbers in a given subset of integers. A parallel version of the Sieve is described that produces computational speedups over 800 on a hypercube with 1,024 processing elements for problems of fixed size. Computational speedups as high as 980 are achieved when the problem size per processor is fixed. The method of parallelization generalizes to other sieves and will be efficient on any ensemble architecture. We investigate two highly parallel sieves using scattered decomposition and compare their performance on a hypercube multiprocessor. A comparison of different parallelization techniques for the sieve illustrates the trade-offs necessary in the design and implementation of massively parallel algorithms for large ensemble computers.

  8. A Faster Parallel Algorithm and Efficient Multithreaded Implementations for Evaluating Betweenness Centrality on Massive Datasets

    SciTech Connect

    Madduri, Kamesh; Ediger, David; Jiang, Karl; Bader, David A.; Chavarría-Miranda, Daniel

    2009-05-29

    We present a new lock-free parallel algorithm for computing betweenness centrality of massive small-world networks. With minor changes to the data structures, our algorithm also achieves better spatial cache locality compared to previous approaches. Betweenness centrality is a key algorithm kernel in the HPCS SSCA#2 Graph Analysis benchmark, which has been extensively used to evaluate the performance of emerging high-performance computing architectures for graph-theoretic computations. We design optimized implementations of betweenness centrality and the SSCA#2 benchmark for two hardware multithreaded systems: a Cray XMT system with the ThreadStorm processor, and a single-socket Sun multicore server with the UltraSparc T2 processor. For a small-world network of 134 million vertices and 1.073 billion edges, the 16-processor XMT system and the 8-core Sun Fire T5120 server achieve TEPS scores (an algorithmic performance count for the SSCA#2 benchmark) of 160 million and 90 million respectively, which corresponds to more than a 2X performance improvement over the previous parallel implementations. To better characterize the performance of these multithreaded systems, we correlate the SSCA#2 performance results with data from the memory-intensive STREAM and RandomAccess benchmarks. Finally, we demonstrate the applicability of our implementation to analyze massive real-world datasets by computing approximate betweenness centrality for a large-scale IMDb movie-actor network.

  9. A Faster Parallel Algorithm and Efficient Multithreaded Implementations for Evaluating Betweenness Centrality on Massive Datasets

    SciTech Connect

    Madduri, Kamesh; Ediger, David; Jiang, Karl; Bader, David A.; Chavarria-Miranda, Daniel

    2009-02-15

    We present a new lock-free parallel algorithm for computing betweenness centralityof massive small-world networks. With minor changes to the data structures, ouralgorithm also achieves better spatial cache locality compared to previous approaches. Betweenness centrality is a key algorithm kernel in HPCS SSCA#2, a benchmark extensively used to evaluate the performance of emerging high-performance computing architectures for graph-theoretic computations. We design optimized implementations of betweenness centrality and the SSCA#2 benchmark for two hardware multithreaded systems: a Cray XMT system with the Threadstorm processor, and a single-socket Sun multicore server with the UltraSPARC T2 processor. For a small-world network of 134 million vertices and 1.073 billion edges, the 16-processor XMT system and the 8-core Sun Fire T5120 server achieve TEPS scores (an algorithmic performance count for the SSCA#2 benchmark) of 160 million and 90 million respectively, which corresponds to more than a 2X performance improvement over the previous parallel implementations. To better characterize the performance of these multithreaded systems, we correlate the SSCA#2 performance results with data from the memory-intensive STREAM and RandomAccess benchmarks. Finally, we demonstrate the applicability of our implementation to analyze massive real-world datasets by computing approximate betweenness centrality for a large-scale IMDb movie-actor network.

  10. A Parallel and Distributed Processing Model of Joint Attention, Social-Cognition and Autism

    PubMed Central

    Mundy, Peter; Sullivan, Lisa; Mastergeorge, Ann M.

    2009-01-01

    Scientific Abstract The impaired development of joint attention is a cardinal feature of autism. Therefore, understanding the nature of joint attention is a central to research on this disorder. Joint attention may be best defined in terms of an information processing system that begins to develop by 4–6 months of age. This system integrates the parallel processing of internal information about one’s own visual attention with external information about the visual attention of other people. This type of joint encoding of information about self and other attention requires the activation of a distributed anterior and posterior cortical attention network. Genetic regulation, in conjunction with self-organizing behavioral activity guides the development of functional connectivity in this network. With practice in infancy the joint processing of self-other attention becomes automatically engaged as an executive function. It can be argued that this executive joint-attention is fundamental to human learning, as well as the development of symbolic thought, social-cognition and social-competence throughout the life span. One advantage of this parallel and distributed processing model of joint attention (PDPM) is that it directly connects theory on social pathology to a range of phenomenon in autism associated with neural connectivity, constructivist and connectionist models of cognitive development, early intervention, activity-dependent gene expression, and atypical ocular motor control. PMID:19358304

  11. An experimental research on the mixing process of supersonic oxygen-iodine parallel streams

    NASA Astrophysics Data System (ADS)

    Wang, Zengqiang; Sang, Fengting; Zhang, Yuelong; Hui, Xiaokang; Xu, Mingxiu; Zhang, Peng; Zhao, Weili; Fang, Benjie; Duo, Liping; Jin, Yuqi

    2014-12-01

    The O2(1Δ)/I2 mixing process is one of the most important steps in chemical oxygen-iodine laser (COIL). Based on the chemical fluorescence method (CFM), a diagnostic system was set up to image electronically excited fluorescent I2(B3П0) by means of a high speed camera. An optimized data analysis approach was proposed to analyze the mixing process of supersonic oxygen-iodine parallel streams, employing a set of qualitative and quantitative parameters and a proper percentage boundary threshold of the fluorescence zone. A slit nozzle bank with supersonic parallel streams and a trip tab set for enhancing the mixing process were designed and fabricated. With the diagnostic system and the data analysis approach, the performance of the trip tab set was examined and is demonstrated in this work. With the mixing enhancement, the fluorescence zone area was enlarged 3.75 times. We have studied the mixing process under different flow conditions and demonstrated the mixing properties with different iodine buffer gases, including N2, Ar, He and CO2. It was found that, among the four tested gases, Ar had the best penetration ability, whilst He showed the best free diffusion ability, and both of them could be well used as the buffer gas in our experiments. These experimental results can be useful for designing and optimizing COIL systems.

  12. Locality-Aware Parallel Process Mapping for Multi-Core HPC Systems

    SciTech Connect

    Hursey, Joshua J; Squyres, Jeffrey M.; Dontje, Terry

    2011-01-01

    High Performance Computing (HPC) systems are composed of servers containing an ever-increasing number of cores. With such high processor core counts, non-uniform memory access (NUMA) architectures are almost universally used to reduce inter-processor and memory communication bottlenecks by distributing processors and memory throughout a server-internal networking topology. Application studies have shown that the tuning of processes placement in a server s NUMA networking topology to the application can have a dramatic impact on performance. The performance implications are magnified when running a parallel job across multiple server nodes, especially with large scale HPC applications. This paper presents the Locality-Aware Mapping Algorithm (LAMA) for distributing the individual processes of a parallel application across processing resources in an HPC system, paying particular attention to the internal server NUMA topologies. The algorithm is able to support both homogeneous and heterogeneous hardware systems, and dynamically adapts to the available hardware and user-specified process layout at run-time. As implemented in Open MPI, the LAMA provides 362,880 mapping permutations and is able to naturally scale out to additional hardware resources as they become available in future architectures.

  13. Parallel Optical Control of Spatiotemporal Neuronal Spike Activity Using High-Speed Digital Light Processing

    PubMed Central

    Jerome, Jason; Foehring, Robert C.; Armstrong, William E.; Spain, William J.; Heck, Detlef H.

    2011-01-01

    Neurons in the mammalian neocortex receive inputs from and communicate back to thousands of other neurons, creating complex spatiotemporal activity patterns. The experimental investigation of these parallel dynamic interactions has been limited due to the technical challenges of monitoring or manipulating neuronal activity at that level of complexity. Here we describe a new massively parallel photostimulation system that can be used to control action potential firing in in vitro brain slices with high spatial and temporal resolution while performing extracellular or intracellular electrophysiological measurements. The system uses digital light processing technology to generate 2-dimensional (2D) stimulus patterns with >780,000 independently controlled photostimulation sites that operate at high spatial (5.4 μm) and temporal (>13 kHz) resolution. Light is projected through the quartz–glass bottom of the perfusion chamber providing access to a large area (2.76 mm × 2.07 mm) of the slice preparation. This system has the unique capability to induce temporally precise action potential firing in large groups of neurons distributed over a wide area covering several cortical columns. Parallel photostimulation opens up new opportunities for the in vitro experimental investigation of spatiotemporal neuronal interactions at a broad range of anatomical scales. PMID:21904526

  14. FAST Observations of Acceleration Processes in the Cusp--Evidence for Parallel Electric Fields

    NASA Technical Reports Server (NTRS)

    Pfaff, R. F.. Jr.; Carlson, C.; McFadden, J.; Ergun, R.; Clemmons, J.; Klumpar D.; Strangeway, R.

    1999-01-01

    The existence of precipitating keV ions in the Earth's cusp originating at the magnetosheath provide unique means to test our understanding of particle acceleration and parallel electric fields in the lower altitude acceleration region. On numerous occasions, the FAST (The Fast Auroral Snapshot) spacecraft has encountered the Earth's cusp regions near its apogee of 4175 km which are characterized by their signatures of dispersed keV ion injections. The FAST instruments also reveal a complex microphysics inherent to many, but not all, of the cusp regions encountered by the spacecraft, that include upgoing ion beams and conics, inverted-V electrons, upgoing electron beams, and spikey DC-coupled electric fields and plasma waves. Detailed inspection of the FAST data often show clear modulation of the precipitating magnetosheath ions that indicate that they are affected by local electric potentials. For example, the magnetosheath ion precipitation is sometimes abruptly shut off precisely in regions where downgoing localized inverted-V electrons are observed. Such observations support the existence of a localized process, such as parallel electric fields, above the spacecraft which accelerate the electrons downward and consequently impede the precipitating ion precipitation. Other acceleration events in the cusp are sometimes organized with an apparent cellular structure that suggests Alfven waves or other large-scale phenomena are controlling the localized potentials. We examine several cusp encounters by the FAST satellite where the modulation of energetic session on acceleration particle populations reveals evidence of localized acceleration, most likely by parallel electric fields.

  15. A Theory of Interactive Parallel Processing: New Capacity Measures and Predictions for a Response Time Inequality Series

    ERIC Educational Resources Information Center

    Townsend, James T.; Wenger, Michael J.

    2004-01-01

    The authors present a theory of stochastic interactive parallel processing with special emphasis on channel interactions and their relation to system capacity. The approach is based both on linear systems theory augmented with stochastic elements and decisional operators and on a metatheory of parallel channels' dependencies that incorporates…

  16. LightForce Photon-Pressure Collision Avoidance: Updated Efficiency Analysis Utilizing a Highly Parallel Simulation Approach

    NASA Astrophysics Data System (ADS)

    Stupl, J.; Faber, N.; Foster, C.; Yang, F.; Nelson, B.; Aziz, J.; Nuttall, A.; Henze, C.; Levit, C.

    2014-09-01

    This paper provides an updated efficiency analysis of the LightForce space debris collision avoidance scheme. LightForce aims to prevent collisions on warning by utilizing photon pressure from ground based, commercial off the shelf lasers. Past research has proven that a few ground-based systems consisting of 10 kW class lasers directed by 1.5 m telescopes with adaptive optics could lower the expected number of collisions in Low Earth Orbit (LEO) by an order of magnitude. Our simulation approach utilizes the entire Two Line Element (TLE) catalogue in LEO for a given day as initial input. Least-squares fitting of a TLE time series is used for an improved orbit estimate. We then calculate the probability of collision for all LEO objects in the catalogue for a time step of the simulation. The conjunctions that exceed a threshold probability of collision are then engaged by a simulated network of laser ground stations. After those engagements, the perturbed orbits are used to re-assess the probability of collision and evaluate the efficiency. This paper describes new simulations with three updated aspects: 1) By utilizing a highly parallel simulation approach employing hundreds of processors, we have extended our analysis to a much broader dataset. The simulation time is extended to one year. 2) We analyze not only the efficiency of LightForce on conjunctions that naturally occur, but also take into account conjunctions caused by orbit perturbations due to LightForce engagements. 3) We use a new simulation approach that is regularly updating the LightForce engagement strategy, as it would be during actual operations. In this paper we present both our simulation approach to parallelize the efficiency analysis, its computational performance and the resulting expected efficiency of the LightForce collision avoidance system.

  17. Refractories for Industrial Processing. Opportunities for Improved Energy Efficiency

    SciTech Connect

    Hemrick, James G.; Hayden, H. Wayne; Angelini, Peter; Moore, Robert E.; Headrick, William L.

    2005-01-01

    Refractories are a class of materials of critical importance to manufacturing industries with high-temperature unit processes. This study describes industrial refractory applications and identifies refractory performance barriers to energy efficiency for processing. The report provides recommendations for R&D pathways leading to improved refractories for energy-efficient manufacturing and processing.

  18. Development of a Robust and Efficient Parallel Solver for Unsteady Turbomachinery Flows

    NASA Technical Reports Server (NTRS)

    West, Jeff; Wright, Jeffrey; Thakur, Siddharth; Luke, Ed; Grinstead, Nathan

    2012-01-01

    The traditional design and analysis practice for advanced propulsion systems relies heavily on expensive full-scale prototype development and testing. Over the past decade, use of high-fidelity analysis and design tools such as CFD early in the product development cycle has been identified as one way to alleviate testing costs and to develop these devices better, faster and cheaper. In the design of advanced propulsion systems, CFD plays a major role in defining the required performance over the entire flight regime, as well as in testing the sensitivity of the design to the different modes of operation. Increased emphasis is being placed on developing and applying CFD models to simulate the flow field environments and performance of advanced propulsion systems. This necessitates the development of next generation computational tools which can be used effectively and reliably in a design environment. The turbomachinery simulation capability presented here is being developed in a computational tool called Loci-STREAM [1]. It integrates proven numerical methods for generalized grids and state-of-the-art physical models in a novel rule-based programming framework called Loci [2] which allows: (a) seamless integration of multidisciplinary physics in a unified manner, and (b) automatic handling of massively parallel computing. The objective is to be able to routinely simulate problems involving complex geometries requiring large unstructured grids and complex multidisciplinary physics. An immediate application of interest is simulation of unsteady flows in rocket turbopumps, particularly in cryogenic liquid rocket engines. The key components of the overall methodology presented in this paper are the following: (a) high fidelity unsteady simulation capability based on Detached Eddy Simulation (DES) in conjunction with second-order temporal discretization, (b) compliance with Geometric Conservation Law (GCL) in order to maintain conservative property on moving meshes for

  19. Parallel Demand-Withdraw Processes in Family Therapy for Adolescent Drug Abuse

    PubMed Central

    Rynes, Kristina N.; Rohrbaugh, Michael J.; Lebensohn-Chialvo, Florencia; Shoham, Varda

    2013-01-01

    Isomorphism, or parallel process, occurs in family therapy when patterns of therapist-client interaction replicate problematic interaction patterns within the family. This study investigated parallel demand-withdraw processes in Brief Strategic Family Therapy (BSFT) for adolescent drug abuse, hypothesizing that therapist-demand/adolescent-withdraw interaction (TD/AW) cycles observed early in treatment would predict poor adolescent outcomes at follow-up for families who exhibited entrenched parent-demand/adolescent-withdraw interaction (PD/AW) before treatment began. Participants were 91 families who received at least 4 sessions of BSFT in a multi-site clinical trial on adolescent drug abuse (Robbins et al., 2011). Prior to receiving therapy, families completed videotaped family interaction tasks from which trained observers coded PD/AW. Another team of raters coded TD/AW during two early BSFT sessions. The main dependent variable was the number of drug use days that adolescents reported in Timeline Follow-Back interviews 7 to 12 months after family therapy began. Zero-inflated Poisson (ZIP) regression analyses supported the main hypothesis, showing that PD/AW and TD/AW interacted to predict adolescent drug use at follow-up. For adolescents in high PD/AW families, higher levels of TD/AW predicted significant increases in drug use at follow-up, whereas for low PD/AW families, TD/AW and follow-up drug use were unrelated. Results suggest that attending to parallel demand-withdraw processes in parent/adolescent and therapist/adolescent dyads may be useful in family therapy for substance-using adolescents. PMID:23438248

  20. Parallel demand-withdraw processes in family therapy for adolescent drug abuse.

    PubMed

    Rynes, Kristina N; Rohrbaugh, Michael J; Lebensohn-Chialvo, Florencia; Shoham, Varda

    2014-06-01

    Isomorphism, or parallel process, occurs in family therapy when patterns of therapist-client interaction replicate problematic interaction patterns within the family. This study investigated parallel demand-withdraw processes in brief strategic family therapy (BSFT) for adolescent drug abuse, hypothesizing that therapist-demand/adolescent-withdraw interaction (TD/AW) cycles observed early in treatment would predict poor adolescent outcomes at follow-up for families who exhibited entrenched parent-demand/adolescent-withdraw interaction (PD/AW) before treatment began. Participants were 91 families who received at least four sessions of BSFT in a multisite clinical trial on adolescent drug abuse (Robbins et al., 2011). Prior to receiving therapy, families completed videotaped family interaction tasks from which trained observers coded PD/AW. Another team of raters coded TD/AW during two early BSFT sessions. The main dependent variable was the number of drug-use days that adolescents reported in timeline follow-back interviews 7 to 12 months after family therapy began. Zero-inflated Poisson regression analyses supported the main hypothesis, showing that PD/AW and TD/AW interacted to predict adolescent drug use at follow-up. For adolescents in high PD/AW families, higher levels of TD/AW predicted significant increases in drug use at follow-up, whereas for low PD/AW families, TD/AW and follow-up drug use were unrelated. Results suggest that attending to parallel demand-withdraw processes in parent-adolescent and therapist-adolescent dyads may be useful in family therapy for substance-using adolescents.

  1. On the Control of Automatic Processes: A Parallel Distributed Processing Account of the Stroop Effect.

    ERIC Educational Resources Information Center

    Cohen, Jonathan D.; And Others

    1990-01-01

    It is proposed that attributes of automatization depend on the strength of a processing pathway, and that strength increases with training. With the Stroop effect as an example, automatic processes are shown through simulation to be continuous and to emerge gradually with practice. (SLD)

  2. Strong Asymmetric Coupling of Two Parallel Exclusion Processes: Effect of Unequal Injection Rates

    NASA Astrophysics Data System (ADS)

    Xiao, Song; Dong, Peng; Zhang, Yingjie; Liu, Yanna

    2016-03-01

    In this letter, strong asymmetric coupling of two parallel exclusion processes: effect of unequal injection rates will be investigated. It is a generalization of the work of Xiao et al. (Phys. Lett. A 8, 374 (2009)), in which the particles only move on two lanes with rate 1 toward right. We can obtain the diverse phase diagram and density profiles of the system. The vertical cluster mean-field approach and extensively Monte Carlo simulations are used to study the system, and theoretical predictions are in excellent agreement with simulation results.

  3. Percolation and anomalous transport as tools in analyzing parallel processing interconnection networks

    SciTech Connect

    McLeod, R.D.; Schellenberg, J.J. ); Hortensius, P.D. )

    1990-04-01

    It is quite apparent that much of the future advances in computation will be derived through the exploitation of parallel processing. Although a wide variety of topologies have been studied and proposed for both general-purpose and algorithm specific applications, there is still considerable discussion over which architectures are better and why. In this paper the authors discuss the application of percolation theory and anomalous transport to the issues of defective computer arrays. Percolation theory is used to discuss the static properties of the defective arrays and anomalous transport theory is used to discuss the dynamics of message passing on the defective array.

  4. Adventures in Parallel Processing: Entry, Descent and Landing Simulation for the Genesis and Stardust Missions

    NASA Technical Reports Server (NTRS)

    Lyons, Daniel T.; Desai, Prasun N.

    2005-01-01

    This paper will describe the Entry, Descent and Landing simulation tradeoffs and techniques that were used to provide the Monte Carlo data required to approve entry during a critical period just before entry of the Genesis Sample Return Capsule. The same techniques will be used again when Stardust returns on January 15, 2006. Only one hour was available for the simulation which propagated 2000 dispersed entry states to the ground. Creative simulation tradeoffs combined with parallel processing were needed to provide the landing footprint statistics that were an essential part of the Go/NoGo decision that authorized release of the Sample Return Capsule a few hours before entry.

  5. Leveraging human oversight and intervention in large-scale parallel processing of open-source data

    NASA Astrophysics Data System (ADS)

    Casini, Enrico; Suri, Niranjan; Bradshaw, Jeffrey M.

    2015-05-01

    The popularity of cloud computing along with the increased availability of cheap storage have led to the necessity of elaboration and transformation of large volumes of open-source data, all in parallel. One way to handle such extensive volumes of information properly is to take advantage of distributed computing frameworks like Map-Reduce. Unfortunately, an entirely automated approach that excludes human intervention is often unpredictable and error prone. Highly accurate data processing and decision-making can be achieved by supporting an automatic process through human collaboration, in a variety of environments such as warfare, cyber security and threat monitoring. Although this mutual participation seems easily exploitable, human-machine collaboration in the field of data analysis presents several challenges. First, due to the asynchronous nature of human intervention, it is necessary to verify that once a correction is made, all the necessary reprocessing is done in chain. Second, it is often needed to minimize the amount of reprocessing in order to optimize the usage of resources due to limited availability. In order to improve on these strict requirements, this paper introduces improvements to an innovative approach for human-machine collaboration in the processing of large amounts of open-source data in parallel.

  6. Target-specific IPSC kinetics promote temporal processing in auditory parallel pathways

    PubMed Central

    Xie, Ruili; Manis, Paul B.

    2013-01-01

    The acoustic environment contains biologically relevant information on time scales from microseconds to tens of seconds. The auditory brainstem nuclei process this temporal information through parallel pathways that originate in the cochlear nucleus from different classes of cells. While the roles of ion channels and excitatory synapses in temporal processing have been well studied, the contribution of inhibition is less well understood. Here, we show in CBA/CaJ mice that the two major projection neurons of the ventral cochlear nucleus, the bushy and T-stellate cells, receive glycinergic inhibition with different synaptic conductance time courses. Bushy cells, which provide precisely timed spike trains used in sound localization and pitch identification, receive slow inhibitory inputs. In contrast, T-stellate cells, which encode slower envelope information, receive inhibition that is eight-fold faster. Both types of inhibition improved the precision of spike timing, but engage different cellular mechanisms and operate on different time scales. Computer models reveal that slow IPSCs in bushy cells can improve spike timing on the scale of tens of microseconds. While fast and slow IPSCs in T-stellate cells improve spike timing on the scale of milliseconds, only fast IPSCs can enhance the detection of narrowband acoustic signals in a complex background. Our results suggest that target-specific IPSC kinetics are critical for the segregated parallel processing of temporal information from the sensory environment. PMID:23345233

  7. Parenting and the parallel processes in parents' counseling supervision for eating-related problems.

    PubMed

    Golan, Moria

    2014-04-01

    This paper presents an integrative model for supervising counselors of parents who face eating-related problems in their families. The model is grounded in the theory of parallel processes which occur during the supervision of health-care professionals as well as the counseling of parents and patients. The aim of this model is to conceptualize components and processes in the supervision space, in order to: (a) create a nurturing environment for health-care facilitators, parents and children, (b) better understand the complex and difficult nature of parenting, the challenge counselors face, and the skills and practices used in parenting and in counseling, and (c) better own practices and oppose the judgment that often dominates in counseling and supervision. This paper reflects upon the tradition of supervision and offers a comprehensive view of this process, including its challenges, skills and practices.

  8. Towards a Standard Mixed-Signal Parallel Processing Architecture for Miniature and Microrobotics

    PubMed Central

    Sadler, Brian M; Hoyos, Sebastian

    2014-01-01

    The conventional analog-to-digital conversion (ADC) and digital signal processing (DSP) architecture has led to major advances in miniature and micro-systems technology over the past several decades. The outlook for these systems is significantly enhanced by advances in sensing, signal processing, communications and control, and the combination of these technologies enables autonomous robotics on the miniature to micro scales. In this article we look at trends in the combination of analog and digital (mixed-signal) processing, and consider a generalized sampling architecture. Employing a parallel analog basis expansion of the input signal, this scalable approach is adaptable and reconfigurable, and is suitable for a large variety of current and future applications in networking, perception, cognition, and control. PMID:26601042

  9. Parallel photonic information processing at gigabyte per second data rates using transient states

    PubMed Central

    Brunner, Daniel; Soriano, Miguel C.; Mirasso, Claudio R.; Fischer, Ingo

    2013-01-01

    The increasing demands on information processing require novel computational concepts and true parallelism. Nevertheless, hardware realizations of unconventional computing approaches never exceeded a marginal existence. While the application of optics in super-computing receives reawakened interest, new concepts, partly neuro-inspired, are being considered and developed. Here we experimentally demonstrate the potential of a simple photonic architecture to process information at unprecedented data rates, implementing a learning-based approach. A semiconductor laser subject to delayed self-feedback and optical data injection is employed to solve computationally hard tasks. We demonstrate simultaneous spoken digit and speaker recognition and chaotic time-series prediction at data rates beyond 1 Gbyte/s. We identify all digits with very low classification errors and perform chaotic time-series prediction with 10% error. Our approach bridges the areas of photonic information processing, cognitive and information science. PMID:23322052

  10. Parallelized multi-graphics processing unit framework for high-speed Gabor-domain optical coherence microscopy.

    PubMed

    Tankam, Patrice; Santhanam, Anand P; Lee, Kye-Sung; Won, Jungeun; Canavesi, Cristina; Rolland, Jannick P

    2014-07-01

    Gabor-domain optical coherence microscopy (GD-OCM) is a volumetric high-resolution technique capable of acquiring three-dimensional (3-D) skin images with histological resolution. Real-time image processing is needed to enable GD-OCM imaging in a clinical setting. We present a parallelized and scalable multi-graphics processing unit (GPU) computing framework for real-time GD-OCM image processing. A parallelized control mechanism was developed to individually assign computation tasks to each of the GPUs. For each GPU, the optimal number of amplitude-scans (A-scans) to be processed in parallel was selected to maximize GPU memory usage and core throughput. We investigated five computing architectures for computational speed-up in processing 1000×1000 A-scans. The proposed parallelized multi-GPU computing framework enables processing at a computational speed faster than the GD-OCM image acquisition, thereby facilitating high-speed GD-OCM imaging in a clinical setting. Using two parallelized GPUs, the image processing of a 1×1×0.6  mm3 skin sample was performed in about 13 s, and the performance was benchmarked at 6.5 s with four GPUs. This work thus demonstrates that 3-D GD-OCM data may be displayed in real-time to the examiner using parallelized GPU processing.

  11. Parallelized multi–graphics processing unit framework for high-speed Gabor-domain optical coherence microscopy

    PubMed Central

    Tankam, Patrice; Santhanam, Anand P.; Lee, Kye-Sung; Won, Jungeun; Canavesi, Cristina; Rolland, Jannick P.

    2014-01-01

    Abstract. Gabor-domain optical coherence microscopy (GD-OCM) is a volumetric high-resolution technique capable of acquiring three-dimensional (3-D) skin images with histological resolution. Real-time image processing is needed to enable GD-OCM imaging in a clinical setting. We present a parallelized and scalable multi-graphics processing unit (GPU) computing framework for real-time GD-OCM image processing. A parallelized control mechanism was developed to individually assign computation tasks to each of the GPUs. For each GPU, the optimal number of amplitude-scans (A-scans) to be processed in parallel was selected to maximize GPU memory usage and core throughput. We investigated five computing architectures for computational speed-up in processing 1000×1000 A-scans. The proposed parallelized multi-GPU computing framework enables processing at a computational speed faster than the GD-OCM image acquisition, thereby facilitating high-speed GD-OCM imaging in a clinical setting. Using two parallelized GPUs, the image processing of a 1×1×0.6  mm3 skin sample was performed in about 13 s, and the performance was benchmarked at 6.5 s with four GPUs. This work thus demonstrates that 3-D GD-OCM data may be displayed in real-time to the examiner using parallelized GPU processing. PMID:24695868

  12. Efficient Quantum Information Processing via Quantum Compressions

    NASA Astrophysics Data System (ADS)

    Deng, Y.; Luo, M. X.; Ma, S. Y.

    2016-01-01

    Our purpose is to improve the quantum transmission efficiency and reduce the resource cost by quantum compressions. The lossless quantum compression is accomplished using invertible quantum transformations and applied to the quantum teleportation and the simultaneous transmission over quantum butterfly networks. New schemes can greatly reduce the entanglement cost, and partially solve transmission conflictions over common links. Moreover, the local compression scheme is useful for approximate entanglement creations from pre-shared entanglements. This special task has not been addressed because of the quantum no-cloning theorem. Our scheme depends on the local quantum compression and the bipartite entanglement transfer. Simulations show the success probability is greatly dependent of the minimal entanglement coefficient. These results may be useful in general quantum network communication.

  13. Efficient Parallel All-Electron Four-Component Dirac-Kohn-Sham Program Using a Distributed Matrix Approach II.

    PubMed

    Storchi, Loriano; Rampino, Sergio; Belpassi, Leonardo; Tarantelli, Francesco; Quiney, Harry M

    2013-12-10

    We propose a new complete memory-distributed algorithm, which significantly improves the parallel implementation of the all-electron four-component Dirac-Kohn-Sham (DKS) module of BERTHA (J. Chem. Theory Comput. 2010, 6, 384). We devised an original procedure for mapping the DKS matrix between an efficient integral-driven distribution, guided by the structure of specific G-spinor basis sets and by density fitting algorithms, and the two-dimensional block-cyclic distribution scheme required by the ScaLAPACK library employed for the linear algebra operations. This implementation, because of the efficiency in the memory distribution, represents a leap forward in the applicability of the DKS procedure to arbitrarily large molecular systems and its porting on last-generation massively parallel systems. The performance of the code is illustrated by some test calculations on several gold clusters of increasing size. The DKS self-consistent procedure has been explicitly converged for two representative clusters, namely Au20 and Au34, for which the density of electronic states is reported and discussed. The largest gold cluster uses more than 39k basis functions and DKS matrices of the order of 23 GB. PMID:26592273

  14. 3D-radiative transfer in terrestrial atmosphere: An efficient parallel numerical procedure

    NASA Astrophysics Data System (ADS)

    Bass, L. P.; Germogenova, T. A.; Nikolaeva, O. V.; Kokhanovsky, A. A.; Kuznetsov, V. S.

    2003-04-01

    Light propagation and scattering in terrestrial atmosphere is usually studied in the framework of the 1D radiative transfer theory [1]. However, in reality particles (e.g., ice crystals, solid and liquid aerosols, cloud droplets) are randomly distributed in 3D space. In particular, their concentrations vary both in vertical and horizontal directions. Therefore, 3D effects influence modern cloud and aerosol retrieval procedures, which are currently based on the 1D radiative transfer theory. It should be pointed out that the standard radiative transfer equation allows to study these more complex situations as well [2]. In recent year the parallel version of the 2D and 3D RADUGA code has been developed. This version is successfully used in gammas and neutrons transport problems [3]. Applications of this code to radiative transfer in atmosphere problems are contained in [4]. Possibilities of code RADUGA are presented in [5]. The RADUGA code system is an universal solver of radiative transfer problems for complicated models, including 2D and 3D aerosol and cloud fields with arbitrary scattering anisotropy, light absorption, inhomogeneous underlying surface and topography. Both delta type and distributed light sources can be accounted for in the framework of the algorithm developed. The accurate numerical procedure is based on the new discrete ordinate SWDD scheme [6]. The algorithm is specifically designed for parallel supercomputers. The version RADUGA 5.1(P) can run on MBC1000M [7] (768 processors with 10 Gb of hard disc memory for each processor). The peak productivity is equal 1 Tfl. Corresponding scalar version RADUGA 5.1 is working on PC. As a first example of application of the algorithm developed, we have studied the shadowing effects of clouds on neighboring cloudless atmosphere, depending on the cloud optical thickness, surface albedo, and illumination conditions. This is of importance for modern satellite aerosol retrieval algorithms development. [1] Sobolev

  15. A cortical architecture on parallel hardware for motion processing in real time.

    PubMed

    Pauwels, Karl; Krüger, Norbert; Lappe, Markus; Wörgötter, Florentin; Van Hulle, Marc M

    2010-01-01

    Walking through a crowd or driving on a busy street requires monitoring your own movement and that of others. The segmentation of these other, independently moving, objects is one of the most challenging tasks in vision as it requires fast and accurate computations for the disentangling of independent motion from egomotion, often in cluttered scenes. This is accomplished in our brain by the dorsal visual stream relying on heavy parallel-hierarchical processing across many areas. This study is the first to utilize the potential of such design in an artificial vision system. We emulate large parts of the dorsal stream in an abstract way and implement an architecture with six interdependent feature extraction stages (e.g., edges, stereo, optical flow, etc.). The computationally highly demanding combination of these features is used to reliably extract moving objects in real time. This way-utilizing the advantages of parallel-hierarchical design-we arrive at a novel and powerful artificial vision system that approaches richness, speed, and accuracy of visual processing in biological systems.

  16. Distributed representation of social odors indicates parallel processing in the antennal lobe of ants.

    PubMed

    Brandstaetter, Andreas Simon; Kleineidam, Christoph Johannes

    2011-11-01

    In colonies of eusocial Hymenoptera cooperation is organized through social odors, and particularly ants rely on a sophisticated odor communication system. Neuronal information about odors is represented in spatial activity patterns in the primary olfactory neuropile of the insect brain, the antennal lobe (AL), which is analog to the vertebrate olfactory bulb. The olfactory system is characterized by neuroanatomical compartmentalization, yet the functional significance of this organization is unclear. Using two-photon calcium imaging, we investigated the neuronal representation of multicomponent colony odors, which the ants assess to discriminate friends (nestmates) from foes (nonnestmates). In the carpenter ant Camponotus floridanus, colony odors elicited spatial activity patterns distributed across different AL compartments. Activity patterns in response to nestmate and nonnestmate colony odors were overlapping. This was expected since both consist of the same components at differing ratios. Colony odors change over time and the nervous system has to constantly adjust for this (template reformation). Measured activity patterns were variable, and variability was higher in response to repeated nestmate than to repeated nonnestmate colony odor stimulation. Variable activity patterns may indicate neuronal plasticity within the olfactory system, which is necessary for template reformation. Our results indicate that information about colony odors is processed in parallel in different neuroanatomical compartments, using the computational power of the whole AL network. Parallel processing might be advantageous, allowing reliable discrimination of highly complex social odors.

  17. Distributed representation of social odors indicates parallel processing in the antennal lobe of ants.

    PubMed

    Brandstaetter, Andreas Simon; Kleineidam, Christoph Johannes

    2011-11-01

    In colonies of eusocial Hymenoptera cooperation is organized through social odors, and particularly ants rely on a sophisticated odor communication system. Neuronal information about odors is represented in spatial activity patterns in the primary olfactory neuropile of the insect brain, the antennal lobe (AL), which is analog to the vertebrate olfactory bulb. The olfactory system is characterized by neuroanatomical compartmentalization, yet the functional significance of this organization is unclear. Using two-photon calcium imaging, we investigated the neuronal representation of multicomponent colony odors, which the ants assess to discriminate friends (nestmates) from foes (nonnestmates). In the carpenter ant Camponotus floridanus, colony odors elicited spatial activity patterns distributed across different AL compartments. Activity patterns in response to nestmate and nonnestmate colony odors were overlapping. This was expected since both consist of the same components at differing ratios. Colony odors change over time and the nervous system has to constantly adjust for this (template reformation). Measured activity patterns were variable, and variability was higher in response to repeated nestmate than to repeated nonnestmate colony odor stimulation. Variable activity patterns may indicate neuronal plasticity within the olfactory system, which is necessary for template reformation. Our results indicate that information about colony odors is processed in parallel in different neuroanatomical compartments, using the computational power of the whole AL network. Parallel processing might be advantageous, allowing reliable discrimination of highly complex social odors. PMID:21849606

  18. Parallel processing and image analysis in the eyes of mantis shrimps.

    PubMed

    Cronin, T W; Marshall, J

    2001-04-01

    The compound eyes of mantis shrimps, a group of tropical marine crustaceans, incorporate principles of serial and parallel processing of visual information that may be applicable to artificial imaging systems. Their eyes include numerous specializations for analysis of the spectral and polarizational properties of light, and include more photoreceptor classes for analysis of ultraviolet light, color, and polarization than occur in any other known visual system. This is possible because receptors in different regions of the eye are anatomically diverse and incorporate unusual structural features, such as spectral filters, not seen in other compound eyes. Unlike eyes of most other animals, eyes of mantis shrimps must move to acquire some types of visual information and to integrate color and polarization with spatial vision. Information leaving the retina appears to be processed into numerous parallel data streams leading into the central nervous system, greatly reducing the analytical requirements at higher levels. Many of these unusual features of mantis shrimp vision may inspire new sensor designs for machine vision. PMID:11341580

  19. A New Parallel Processing Scheme Enabling Full Monte Carlo EAS Simulation in the GZK Energy Region

    NASA Astrophysics Data System (ADS)

    Kasahara, K.; Cohen, F.

    We developed a new parallel processing method enabling full M.C EAS simulation (say, with minimum energy of 500 keV) without using thin sampling even at 1019 eV. Normally, distributed-parallel processing needs a specific software and programs must be organized to match with such system. During the computation such a scheme also requires complex communications among many computer hosts. Our scheme first creates a skeleton of a shower, and smashes it into n-peaces and distributes the peaces to n- cpu to flesh them. After each peace is completely fleshed, they are assembled to make a complete picture of the shower. Thus, during the computation need no communication. With n=50, a 1019 eV shower can be simulated in ~10 days. For a 1020 eV shower, we may randomly sample a fraction of n-peases (say, 100 for n=1000), and safely econstruct whole picture of the shower. The scheme dose not use any weight on each particle and very much stable. The scheme has been implemented in Cosmos code. To produce a number of showers with full fluctuations, we have also developed a new method which utilizes the present result. The latter is used for the TA experiment and is described in an accompanying paper.

  20. Investigation of Mediational Processes Using Parallel Process Latent Growth Curve Modeling.

    ERIC Educational Resources Information Center

    Cheong, JeeWon; MacKinnon, David P.; Khoo, Siek Toon

    2003-01-01

    Investigated a method to evaluate mediational processes using latent growth curve modeling and tested it with empirical data from a longitudinal steroid use prevention program focusing on 1,506 high school football players over 4 years. Findings suggest the usefulness of the approach. (SLD)

  1. Efficient solar cells by space processing

    NASA Technical Reports Server (NTRS)

    Schmidt, F. A.; Campisi, G. J.; Bevolo, A.; Shanks, H. R.; Williams, D. E.

    1979-01-01

    Thin films of electron beam evaporated silicon were deposited on molybdenum, tantalum, tungsten and molybdenum disilicide under ultrahigh vacuum conditions. Mass spectra from a quadrapole residual gas analyzer were used to determine the partial pressure of 13 residual gases during each processing step. Surface contamination and interdiffusion were monitored by in situ Auger electron spectrometry. The presence of phosphorus in the silicon was responsible for attaining elevated temperatures with silicide formations. Heteroepitaxial silicon growth was sensitive to the presence of oxygen during deposition, the rate and length of deposition as well as the substrate orientation.

  2. Parallel distributed processing and neuropsychology: a neural network model of Wisconsin Card Sorting and verbal fluency.

    PubMed

    Parks, R W; Levine, D S; Long, D L; Crockett, D J; Dalton, I E; Weingartner, H; Fedio, P; Coburn, K L; Siler, G; Matthews, J R

    1992-06-01

    Neural networks can be used as a tool in the explanation of neuropsychological data. Using the Hebbian Learning Rule and other such principles as competition and modifiable interlevel feedback, researchers have successfully modeled a widely used neuropsychological test, the Wisconsin Card Sorting Test. One of these models is reviewed here and extended to a qualitative analysis of how verbal fluency might be modeled, which demonstrates the importance of accounting for the attentional components of both tests. Difficulties remain in programming sequential cognitive processes within a parallel distributed processing (PDP) framework and integrating exceedingly complex neuropsychological tests such as Proverbs. PDP neural network methodology offers neuropsychologists co-validation procedures within narrowly defined areas of reliability and validity.

  3. Efficient implementation of a multidimensional fast fourier transform on a distributed-memory parallel multi-node computer

    DOEpatents

    Bhanot, Gyan V.; Chen, Dong; Gara, Alan G.; Giampapa, Mark E.; Heidelberger, Philip; Steinmacher-Burow, Burkhard D.; Vranas, Pavlos M.

    2008-01-01

    The present in invention is directed to a method, system and program storage device for efficiently implementing a multidimensional Fast Fourier Transform (FFT) of a multidimensional array comprising a plurality of elements initially distributed in a multi-node computer system comprising a plurality of nodes in communication over a network, comprising: distributing the plurality of elements of the array in a first dimension across the plurality of nodes of the computer system over the network to facilitate a first one-dimensional FFT; performing the first one-dimensional FFT on the elements of the array distributed at each node in the first dimension; re-distributing the one-dimensional FFT-transformed elements at each node in a second dimension via "all-to-all" distribution in random order across other nodes of the computer system over the network; and performing a second one-dimensional FFT on elements of the array re-distributed at each node in the second dimension, wherein the random order facilitates efficient utilization of the network thereby efficiently implementing the multidimensional FFT. The "all-to-all" re-distribution of array elements is further efficiently implemented in applications other than the multidimensional FFT on the distributed-memory parallel supercomputer.

  4. Efficient implementation of multidimensional fast fourier transform on a distributed-memory parallel multi-node computer

    DOEpatents

    Bhanot, Gyan V.; Chen, Dong; Gara, Alan G.; Giampapa, Mark E.; Heidelberger, Philip; Steinmacher-Burow, Burkhard D.; Vranas, Pavlos M.

    2012-01-10

    The present in invention is directed to a method, system and program storage device for efficiently implementing a multidimensional Fast Fourier Transform (FFT) of a multidimensional array comprising a plurality of elements initially distributed in a multi-node computer system comprising a plurality of nodes in communication over a network, comprising: distributing the plurality of elements of the array in a first dimension across the plurality of nodes of the computer system over the network to facilitate a first one-dimensional FFT; performing the first one-dimensional FFT on the elements of the array distributed at each node in the first dimension; re-distributing the one-dimensional FFT-transformed elements at each node in a second dimension via "all-to-all" distribution in random order across other nodes of the computer system over the network; and performing a second one-dimensional FFT on elements of the array re-distributed at each node in the second dimension, wherein the random order facilitates efficient utilization of the network thereby efficiently implementing the multidimensional FFT. The "all-to-all" re-distribution of array elements is further efficiently implemented in applications other than the multidimensional FFT on the distributed-memory parallel supercomputer.

  5. Parallel implementation of 3D FFT with volumetric decomposition schemes for efficient molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Jung, Jaewoon; Kobayashi, Chigusa; Imamura, Toshiyuki; Sugita, Yuji

    2016-03-01

    Three-dimensional Fast Fourier Transform (3D FFT) plays an important role in a wide variety of computer simulations and data analyses, including molecular dynamics (MD) simulations. In this study, we develop hybrid (MPI+OpenMP) parallelization schemes of 3D FFT based on two new volumetric decompositions, mainly for the particle mesh Ewald (PME) calculation in MD simulations. In one scheme, (1d_Alltoall), five all-to-all communications in one dimension are carried out, and in the other, (2d_Alltoall), one two-dimensional all-to-all communication is combined with two all-to-all communications in one dimension. 2d_Alltoall is similar to the conventional volumetric decomposition scheme. We performed benchmark tests of 3D FFT for the systems with different grid sizes using a large number of processors on the K computer in RIKEN AICS. The two schemes show comparable performances, and are better than existing 3D FFTs. The performances of 1d_Alltoall and 2d_Alltoall depend on the supercomputer network system and number of processors in each dimension. There is enough leeway for users to optimize performance for their conditions. In the PME method, short-range real-space interactions as well as long-range reciprocal-space interactions are calculated. Our volumetric decomposition schemes are particularly useful when used in conjunction with the recently developed midpoint cell method for short-range interactions, due to the same decompositions of real and reciprocal spaces. The 1d_Alltoall scheme of 3D FFT takes 4.7 ms to simulate one MD cycle for a virus system containing more than 1 million atoms using 32,768 cores on the K computer.

  6. Teaching ethics to engineers: ethical decision making parallels the engineering design process.

    PubMed

    Bero, Bridget; Kuhlman, Alana

    2011-09-01

    In order to fulfill ABET requirements, Northern Arizona University's Civil and Environmental engineering programs incorporate professional ethics in several of its engineering courses. This paper discusses an ethics module in a 3rd year engineering design course that focuses on the design process and technical writing. Engineering students early in their student careers generally possess good black/white critical thinking skills on technical issues. Engineering design is the first time students are exposed to "grey" or multiple possible solution technical problems. To identify and solve these problems, the engineering design process is used. Ethical problems are also "grey" problems and present similar challenges to students. Students need a practical tool for solving these ethical problems. The step-wise engineering design process was used as a model to demonstrate a similar process for ethical situations. The ethical decision making process of Martin and Schinzinger was adapted for parallelism to the design process and presented to students as a step-wise technique for identification of the pertinent ethical issues, relevant moral theories, possible outcomes and a final decision. Students had greatest difficulty identifying the broader, global issues presented in an ethical situation, but by the end of the module, were better able to not only identify the broader issues, but also to more comprehensively assess specific issues, generate solutions and a desired response to the issue.

  7. A Computationally Efficient Parallel Levenberg-Marquardt Algorithm for Large-Scale Big-Data Inversion

    NASA Astrophysics Data System (ADS)

    Lin, Y.; O'Malley, D.; Vesselinov, V. V.

    2015-12-01

    Inverse modeling seeks model parameters given a set of observed state variables. However, for many practical problems due to the facts that the observed data sets are often large and model parameters are often numerous, conventional methods for solving the inverse modeling can be computationally expensive. We have developed a new, computationally-efficient Levenberg-Marquardt method for solving large-scale inverse modeling. Levenberg-Marquardt methods require the solution of a dense linear system of equations which can be prohibitively expensive to compute for large-scale inverse problems. Our novel method projects the original large-scale linear problem down to a Krylov subspace, such that the dimensionality of the measurements can be significantly reduced. Furthermore, instead of solving the linear system for every Levenberg-Marquardt damping parameter, we store the Krylov subspace computed when solving the first damping parameter and recycle it for all the following damping parameters. The efficiency of our new inverse modeling algorithm is significantly improved by using these computational techniques. We apply this new inverse modeling method to invert for a random transitivity field. Our algorithm is fast enough to solve for the distributed model parameters (transitivity) at each computational node in the model domain. The inversion is also aided by the use regularization techniques. The algorithm is coded in Julia and implemented in the MADS computational framework (http://mads.lanl.gov). Julia is an advanced high-level scientific programing language that allows for efficient memory management and utilization of high-performance computational resources. By comparing with a Levenberg-Marquardt method using standard linear inversion techniques, our Levenberg-Marquardt method yields speed-up ratio of 15 in a multi-core computational environment and a speed-up ratio of 45 in a single-core computational environment. Therefore, our new inverse modeling method is a

  8. Stage efficiency in the analysis of thermochemical water decomposition processes

    NASA Technical Reports Server (NTRS)

    Conger, W. L.; Funk, J. E.; Carty, R. H.; Soliman, M. A.; Cox, K. E.

    1976-01-01

    The procedure for analyzing thermochemical water-splitting processes using the figure of merit is expanded to include individual stage efficiencies and loss coefficients. The use of these quantities to establish the thermodynamic insufficiencies of each stage is shown. A number of processes are used to illustrate these concepts and procedures and to demonstrate the facility with which process steps contributing most to the cycle efficiency are found. The procedure allows attention to be directed to those steps of the process where the greatest increase in total cycle efficiency can be obtained.

  9. Massively Parallel Signal Processing using the Graphics Processing Unit for Real-Time Brain-Computer Interface Feature Extraction.

    PubMed

    Wilson, J Adam; Williams, Justin C

    2009-01-01

    The clock speeds of modern computer processors have nearly plateaued in the past 5 years. Consequently, neural prosthetic systems that rely on processing large quantities of data in a short period of time face a bottleneck, in that it may not be possible to process all of the data recorded from an electrode array with high channel counts and bandwidth, such as electrocorticographic grids or other implantable systems. Therefore, in this study a method of using the processing capabilities of a graphics card [graphics processing unit (GPU)] was developed for real-time neural signal processing of a brain-computer interface (BCI). The NVIDIA CUDA system was used to offload processing to the GPU, which is capable of running many operations in parallel, potentially greatly increasing the speed of existing algorithms. The BCI system records many channels of data, which are processed and translated into a control signal, such as the movement of a computer cursor. This signal processing chain involves computing a matrix-matrix multiplication (i.e., a spatial filter), followed by calculating the power spectral density on every channel using an auto-regressive method, and finally classifying appropriate features for control. In this study, the first two computationally intensive steps were implemented on the GPU, and the speed was compared to both the current implementation and a central processing unit-based implementation that uses multi-threading. Significant performance gains were obtained with GPU processing: the current implementation processed 1000 channels of 250 ms in 933 ms, while the new GPU method took only 27 ms, an improvement of nearly 35 times.

  10. LightForce Photon-Pressure Collision Avoidance: Updated Efficiency Analysis Utilizing a Highly Parallel Simulation Approach

    NASA Technical Reports Server (NTRS)

    Stupl, Jan; Faber, Nicolas; Foster, Cyrus; Yang, Fan Yang; Nelson, Bron; Aziz, Jonathan; Nuttall, Andrew; Henze, Chris; Levit, Creon

    2014-01-01

    This paper provides an updated efficiency analysis of the LightForce space debris collision avoidance scheme. LightForce aims to prevent collisions on warning by utilizing photon pressure from ground based, commercial off the shelf lasers. Past research has shown that a few ground-based systems consisting of 10 kilowatt class lasers directed by 1.5 meter telescopes with adaptive optics could lower the expected number of collisions in Low Earth Orbit (LEO) by an order of magnitude. Our simulation approach utilizes the entire Two Line Element (TLE) catalogue in LEO for a given day as initial input. Least-squares fitting of a TLE time series is used for an improved orbit estimate. We then calculate the probability of collision for all LEO objects in the catalogue for a time step of the simulation. The conjunctions that exceed a threshold probability of collision are then engaged by a simulated network of laser ground stations. After those engagements, the perturbed orbits are used to re-assess the probability of collision and evaluate the efficiency of the system. This paper describes new simulations with three updated aspects: 1) By utilizing a highly parallel simulation approach employing hundreds of processors, we have extended our analysis to a much broader dataset. The simulation time is extended to one year. 2) We analyze not only the efficiency of LightForce on conjunctions that naturally occur, but also take into account conjunctions caused by orbit perturbations due to LightForce engagements. 3) We use a new simulation approach that is regularly updating the LightForce engagement strategy, as it would be during actual operations. In this paper we present our simulation approach to parallelize the efficiency analysis, its computational performance and the resulting expected efficiency of the LightForce collision avoidance system. Results indicate that utilizing a network of four LightForce stations with 20 kilowatt lasers, 85% of all conjunctions with a

  11. Automated Image Processing : An Efficient Pipeline Data-Flow Architecture

    NASA Astrophysics Data System (ADS)

    Barreault, G.; Rivoire, A.; Jourlin, M.; Laboure, M. J.; Ramon, S.; Zeboudj, R.; Pinoli, J. C.

    1987-10-01

    In the context of Expert-Systems there is a pressing need of efficient Image Processing algorithms to fit the various applications. This paper presents a new electronic card that performs Image Acquisition, Processing and Display, with an IBM-PC/XT or AT as a host computer. This card features a Pipeline data flow architecture, an efficient and cost effective solution to most of the Image Processing problems.

  12. Distinct cerebellar lobules process arousal, valence and their interaction in parallel following a temporal hierarchy.

    PubMed

    Styliadis, Charis; Ioannides, Andreas A; Bamidis, Panagiotis D; Papadelis, Christos

    2015-04-15

    The cerebellum participates in emotion-related neural circuits formed by different cortical and subcortical areas, which sub-serve arousal and valence. Recent neuroimaging studies have shown a functional specificity of cerebellar lobules in the processing of emotional stimuli. However, little is known about the temporal component of this process. The goal of the current study is to assess the spatiotemporal profile of neural responses within the cerebellum during the processing of arousal and valence. We hypothesized that the excitation and timing of distinct cerebellar lobules is influenced by the emotional content of the stimuli. By using magnetoencephalography, we recorded magnetic fields from twelve healthy human individuals while passively viewing affective pictures rated along arousal and valence. By using a beamformer, we localized gamma-band activity in the cerebellum across time and we related the foci of activity to the anatomical organization of the cerebellum. Successive cerebellar activations were observed within distinct lobules starting ~160ms after the stimuli onset. Arousal was processed within both vermal (VI and VIIIa) and hemispheric (left Crus II) lobules. Valence (left VI) and its interaction (left V and left Crus I) with arousal were processed only within hemispheric lobules. Arousal processing was identified first at early latencies (160ms) and was long-lived (until 980ms). In contrast, the processing of valence and its interaction to arousal was short lived at later stages (420-530ms and 570-640ms respectively). Our findings provide for the first time evidence that distinct cerebellar lobules process arousal, valence, and their interaction in a parallel yet temporally hierarchical manner determined by the emotional content of the stimuli. PMID:25665964

  13. Efficient sampling of protein conformational space using fast loop building and batch minimization on highly parallel computers.

    PubMed

    Tyka, Michael D; Jung, Kenneth; Baker, David

    2012-12-01

    All-atom sampling is a critical and compute-intensive end stage to protein structural modeling. Because of the vast size and extreme ruggedness of conformational space, even close to the native structure, the high-resolution sampling problem is almost as difficult as predicting the rough fold of a protein. Here, we present a combination of new algorithms that considerably speed up the exploration of very rugged conformational landscapes and are capable of finding heretofore hidden low-energy states. The algorithm is based on a hierarchical workflow and can be parallelized on supercomputers with up to 128,000 compute cores with near perfect efficiency. Such scaling behavior is notable, as with Moore's law continuing only in the number of cores per chip, parallelizability is a critical property of new algorithms. Using the enhanced sampling power, we have uncovered previously invisible deficiencies in the Rosetta force field and created an extensive decoy training set for optimizing and testing force fields.

  14. Extended parallel process model and H5N1 influenza virus.

    PubMed

    Siu, Wanda

    2008-04-01

    This study integrated the Extended Parallel Process Model and forewarning cues to assess the promotion of preventive measures against the H5N1 influenza virus, a significant health threat that affects Asia, Europe, and the USA. There are two types of forewarning, (1) telling the audience that they will hear messages intended to persuade them and (2) telling the audience the topic and stance of the impending persuasive message. Analysis of ratings by 265 undergraduates indicated that forewarnings of the topic and stance of a promotional message on the H5N1 virus facilitated elaboration of coping-related thoughts which enhance perceived self-efficacy and a stronger behavioral intention to combat H5N1. Conversely, the elaboration of danger-related thoughts evoked some fear but enhanced source perception.

  15. Biological dosimetry by chromosome aberration scoring with parallel image processing with the Heidelberg POLYP Polyprocessor system

    SciTech Connect

    Bille, J.; Scharfenberg, H.; Maenner, R.

    1983-01-01

    Chromosome aberrations in human peripheral blood are recognized parameters of cellular damage and are used as indicators of exposure to ionizing radiation. In order to reach the low dose range, up to 10,000 metaphase cells each consisting of 46 chromosomes have to be analysed for each radiation exposed person. In order to perform this task within reasonable time limits the application of the Heidelberg POLYP Polyprocessor is considered. The POLYP consists of a number of processor modules and several global memory modules which are interconnected by a multi-common-bus for parallel data transfers and a multiple synchronization bus for processor/task-scheduling. The system is designed for handling large amounts of data in real time as is typical for image processing applications.

  16. When parallel processing in visual word recognition is not enough: new evidence from naming.

    PubMed

    Roberts, Martha Anne; Rastle, Kathleen; Coltheart, Max; Besner, Derek

    2003-06-01

    Low-frequency irregular words are named more slowly and are more error prone than low-frequency regular words (the regularity effect). Rastle and Coltheart (1999) reported that this irregularity cost is modulated by the serial position of the irregular grapheme-phoneme correspondence, such that words with early irregularities exhibit a larger cost than words with late ones. They argued that these data implicate rule-based serial processing, and they also reported a successful simulation with a model that has a rule-based serial component--the DRC model of reading aloud (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001). However, Zorzi (2000) also simulated these data with a model that operates solely in parallel. Furthermore, Kwantes and Mewhort (1999) simulated these data with a serial processing model that has no rules for converting orthography to phonology. The human data reported by Rastle and Coltheart therefore neither require a serial processing account, nor successfully discriminate among a number of computational models of reading aloud. New data are presented wherein an interaction between the effects of regularity and serial position of irregularity is again reported for human readers. The DRC model simulated this interaction; no other implemented computational model does so. The present results are thus consistent with rule-based serial processing in reading aloud.

  17. MultiScheme: a parallel-processing system based on MIT (Massachusetts Institute of Technology) scheme. Doctoral thesis

    SciTech Connect

    Miller, J.S.

    1987-09-01

    MultiScheme is a fully operational parallel-programming system based upon the Scheme dialect of Lisp. Like its Lisp ancestors, MultiScheme provides a conducive environment for prototyping and testing new linguistic structures and programming methodologies. MultiScheme supports a diverse community of users who have a wide range of interests in parallel programming. MultiScheme's flexible support for system-based experiments in parallel processing has enabled it to serve as a development vehicle for university and industrial research. At the same time, MultiScheme is sufficiently robust, and supports a sufficiently wide range of parallel-processing applications, that it has become the base for a commercial product, the Butterfly Lisp System produced by BBN Advanced Computers, Inc.

  18. In-Database Raster Analytics: Map Algebra and Parallel Processing in Oracle Spatial Georaster

    NASA Astrophysics Data System (ADS)

    Xie, Q. J.; Zhang, Z. Z.; Ravada, S.

    2012-07-01

    Over the past decade several products have been using enterprise database technology to store and manage geospatial imagery and raster data inside RDBMS, which in turn provides the best manageability and security. With the data volume growing exponentially, real-time or near real-time processing and analysis of such big data becomes more challenging. Oracle Spatial GeoRaster, different from most other products, takes the enterprise database-centric approach for both data management and data processing. This paper describes one of the central components of this database-centric approach: the processing engine built completely inside the database. Part of this processing engine is raster algebra, which we call the In-database Raster Analytics. This paper discusses the three key characteristics of this in-database analytics engine and the benefits. First, it moves the data processing closer to the data instead of moving the data to the processing, which helps achieve greater performance by overcoming the bottleneck of computer networks. Second, we designed and implemented a new raster algebra expression language. This language is based on PL/SQL and is currently focused on the "local" function type of map algebra. This language includes general arithmetic, logical and relational operators and any combination of them, which dramatically improves the analytical capability of the GeoRaster database. The third feature is the implementation of parallel processing of such operations to further improve performance. This paper also presents some sample use cases. The testing results demonstrate that this in-database approach for raster analytics can effectively help solve the biggest performance challenges we are facing today with big raster and image data.

  19. Combined shared and distributed memory ab-initio computations of molecular-hydrogen systems in the correlated state: Process pool solution and two-level parallelism

    NASA Astrophysics Data System (ADS)

    Biborski, Andrzej; Kądzielawa, Andrzej P.; Spałek, Józef

    2015-12-01

    An efficient computational scheme devised for investigations of ground state properties of the electronically correlated systems is presented. As an example, (H2)n chain is considered with the long-range electron-electron interactions taken into account. The implemented procedure covers: (i) single-particle Wannier wave-function basis construction in the correlated state, (ii) microscopic parameters calculation, and (iii) ground state energy optimization. The optimization loop is based on highly effective process-pool solution - specific root-workers approach. The hierarchical, two-level parallelism was applied: both shared (by use of Open Multi-Processing) and distributed (by use of Message Passing Interface) memory models were utilized. We discuss in detail the feature that such approach results in a substantial increase of the calculation speed reaching factor of 300 for the fully parallelized solution. The scheme elaborated in detail reflects the situation in which the most demanding task is the single-particle basis optimization.

  20. Neural decoding using a parallel sequential Monte Carlo method on point processes with ensemble effect.

    PubMed

    Xu, Kai; Wang, Yiwen; Wang, Fang; Liao, Yuxi; Zhang, Qiaosheng; Li, Hongbao; Zheng, Xiaoxiang

    2014-01-01

    Sequential Monte Carlo estimation on point processes has been successfully applied to predict the movement from neural activity. However, there exist some issues along with this method such as the simplified tuning model and the high computational complexity, which may degenerate the decoding performance of motor brain machine interfaces. In this paper, we adopt a general tuning model which takes recent ensemble activity into account. The goodness-of-fit analysis demonstrates that the proposed model can predict the neuronal response more accurately than the one only depending on kinematics. A new sequential Monte Carlo algorithm based on the proposed model is constructed. The algorithm can significantly reduce the root mean square error of decoding results, which decreases 23.6% in position estimation. In addition, we accelerate the decoding speed by implementing the proposed algorithm in a massive parallel manner on GPU. The results demonstrate that the spike trains can be decoded as point process in real time even with 8000 particles or 300 neurons, which is over 10 times faster than the serial implementation. The main contribution of our work is to enable the sequential Monte Carlo algorithm with point process observation to output the movement estimation much faster and more accurately.

  1. Neural Decoding Using a Parallel Sequential Monte Carlo Method on Point Processes with Ensemble Effect

    PubMed Central

    Wang, Fang; Liao, Yuxi; Zheng, Xiaoxiang

    2014-01-01

    Sequential Monte Carlo estimation on point processes has been successfully applied to predict the movement from neural activity. However, there exist some issues along with this method such as the simplified tuning model and the high computational complexity, which may degenerate the decoding performance of motor brain machine interfaces. In this paper, we adopt a general tuning model which takes recent ensemble activity into account. The goodness-of-fit analysis demonstrates that the proposed model can predict the neuronal response more accurately than the one only depending on kinematics. A new sequential Monte Carlo algorithm based on the proposed model is constructed. The algorithm can significantly reduce the root mean square error of decoding results, which decreases 23.6% in position estimation. In addition, we accelerate the decoding speed by implementing the proposed algorithm in a massive parallel manner on GPU. The results demonstrate that the spike trains can be decoded as point process in real time even with 8000 particles or 300 neurons, which is over 10 times faster than the serial implementation. The main contribution of our work is to enable the sequential Monte Carlo algorithm with point process observation to output the movement estimation much faster and more accurately. PMID:24949462

  2. Efficiency and Effectiveness of a Resident Assistant Selection Process.

    ERIC Educational Resources Information Center

    Broitman, Thomas

    The American phenomenon of "more is better" extends a value-loaded concept implicit in budget preparation. At any university, the scope, magnitude and cost of a residence hall assistant program selection process is a metaphor to illustrate efficiency and effectiveness of human resources. In order to discover a more efficient and effective…

  3. Membrane Transport Processes Analyzed by a Highly Parallel Nanopore Chip System at Single Protein Resolution.

    PubMed

    Urban, Michael; Vor der Brüggen, Marc; Tampé, Robert

    2016-01-01

    Membrane protein transport on the single protein level still evades detailed analysis, if the substrate translocated is non-electrogenic. Considerable efforts have been made in this field, but techniques enabling automated high-throughput transport analysis in combination with solvent-free lipid bilayer techniques required for the analysis of membrane transporters are rare. This class of transporters however is crucial in cell homeostasis and therefore a key target in drug development and methodologies to gain new insights desperately needed. The here presented manuscript describes the establishment and handling of a novel biochip for the analysis of membrane protein mediated transport processes at single transporter resolution. The biochip is composed of microcavities enclosed by nanopores that is highly parallel in its design and can be produced in industrial grade and quantity. Protein-harboring liposomes can directly be applied to the chip surface forming self-assembled pore-spanning lipid bilayers using SSM-techniques (solid supported lipid membranes). Pore-spanning parts of the membrane are freestanding, providing the interface for substrate translocation into or out of the cavity space, which can be followed by multi-spectral fluorescent readout in real-time. The establishment of standard operating procedures (SOPs) allows the straightforward establishment of protein-harboring lipid bilayers on the chip surface of virtually every membrane protein that can be reconstituted functionally. The sole prerequisite is the establishment of a fluorescent read-out system for non-electrogenic transport substrates. High-content screening applications are accomplishable by the use of automated inverted fluorescent microscopes recording multiple chips in parallel. Large data sets can be analyzed using the freely available custom-designed analysis software. Three-color multi spectral fluorescent read-out furthermore allows for unbiased data discrimination into different

  4. SIAM Conference on Parallel Processing for Scientific Computing - March 12-14, 2008

    SciTech Connect

    2008-09-08

    The themes of the 2008 conference included, but were not limited to: Programming languages, models, and compilation techniques; The transition to ubiquitous multicore/manycore processors; Scientific computing on special-purpose processors (Cell, GPUs, etc.); Architecture-aware algorithms; From scalable algorithms to scalable software; Tools for software development and performance evaluation; Global perspectives on HPC; Parallel computing in industry; Distributed/grid computing; Fault tolerance; Parallel visualization and large scale data management; and The future of parallel architectures.

  5. Parallel processing approach for radiative heat transfer prediction in participating media

    NASA Astrophysics Data System (ADS)

    Saltiel, C.; Naraghi, M. H. N.

    1993-10-01

    Numerical analysis of radiative transfer in participating media can be very complex. Computer simulations of practical situations often require both large computer memory and long calculation times. The use of massively parallel machines has proven very effective in simulating large complex systems. This technical note presents a unified matrix formulation for node-to-node-based radiative exchange in isotropically scattering homogeneous media using the discrete exchange factor (DEF) method. Computational implementation is compared between serial and parallel computing machines. The results demonstrate that parallel computing has the potential for changing the nature of radiative transfer calculations. Parallel computing allows for faster, more manageable calculations; it is especially effective for nonlinear problems.

  6. Rapid LC-MS drug metabolite profiling using microsomal enzyme bioreactors in a parallel processing format.

    PubMed

    Bajrami, Besnik; Zhao, Linlin; Schenkman, John B; Rusling, James F

    2009-12-15

    Silica nanoparticle bioreactors featuring thin films of enzymes and polyions were utilized in a novel high-throughput 96-well plate format for drug metabolism profiling. The utility of the approach was illustrated by investigating the metabolism of the drugs diclofenac (DCF), troglitazone (TGZ), and raloxifene, for which we observed known metabolic oxidation and bioconjugation pathways and turnover rates. A broad range of enzymes was included by utilizing human liver (HLM), rat liver (RLM) and bicistronic human-cyt P450 3A4 (bicis.-3A4) microsomes as enzyme sources. This parallel approach significantly shortens sample preparation steps compared to an earlier manual processing with nanoparticle bioreactors, allowing a range of significant enzyme reactions to be processed simultaneously. Enzyme turnover rates using the microsomal bioreactors were 2-3 fold larger compared to using conventional microsomal dispersions, most likely because of better accessibility of the enzymes. Ketoconazole (KET) and quinidine (QIN), substrates specific to cyt P450 3A enzymes, were used to demonstrate applicability to establish potentially toxic drug-drug interactions involving enzyme inhibition and acceleration. PMID:19904994

  7. Parallel processing in the brain's visual form system: an fMRI study

    PubMed Central

    Shigihara, Yoshihito; Zeki, Semir

    2014-01-01

    We here extend and complement our earlier time-based, magneto-encephalographic (MEG), study of the processing of forms by the visual brain (Shigihara and Zeki, 2013) with a functional magnetic resonance imaging (fMRI) study, in order to better localize the activity produced in early visual areas when subjects view simple geometric stimuli of increasing perceptual complexity (lines, angles, rhombuses) constituted from the same elements (lines). Our results show that all three categories of form activate all three visual areas with which we were principally concerned (V1–V3), with angles producing the strongest and rhombuses the weakest activity in all three. The difference between the activity produced by angles and rhombuses was significant, that between lines and rhombuses was trend significant while that between lines and angles was not. Taken together with our earlier MEG results, the present ones suggest that a parallel strategy is used in processing forms, in addition to the well-documented hierarchical strategy. PMID:25126064

  8. Numerical processing efficiency improved in experienced mental abacus children.

    PubMed

    Wang, Yunqi; Geng, Fengji; Hu, Yuzheng; Du, Fenglei; Chen, Feiyan

    2013-05-01

    Experienced mental abacus (MA) users are able to perform mental arithmetic calculations with unusual speed and accuracy. However, it remains unclear whether their extraordinary gains in mental arithmetic ability are accompanied by an improvement in numerical processing efficiency. To address this question, the present study, using a numerical Stroop paradigm, examined the numerical processing efficiency of experienced MA children, MA beginners and their respective peers. The results showed that experienced MA children were less influenced than their peers by physical size information when intentionally processing numerical magnitude information, but they were more influenced than their peers by numerical magnitude information when intentionally processing physical size information. By contrast, MA beginners and peers showed no differences in the reciprocal influences between the two conflicting dimensions. These findings indicate that substantial gains in numerical processing efficiency could be achieved through long-term intensive MA training. Implications for numerical magnitude representations and for training students with mathematical learning disabilities are discussed.

  9. A parallel offline CFD and closed-form approximation strategy for computationally efficient analysis of complex fluid flows

    NASA Astrophysics Data System (ADS)

    Allphin, Devin

    Computational fluid dynamics (CFD) solution approximations for complex fluid flow problems have become a common and powerful engineering analysis technique. These tools, though qualitatively useful, remain limited in practice by their underlying inverse relationship between simulation accuracy and overall computational expense. While a great volume of research has focused on remedying these issues inherent to CFD, one traditionally overlooked area of resource reduction for engineering analysis concerns the basic definition and determination of functional relationships for the studied fluid flow variables. This artificial relationship-building technique, called meta-modeling or surrogate/offline approximation, uses design of experiments (DOE) theory to efficiently approximate non-physical coupling between the variables of interest in a fluid flow analysis problem. By mathematically approximating these variables, DOE methods can effectively reduce the required quantity of CFD simulations, freeing computational resources for other analytical focuses. An idealized interpretation of a fluid flow problem can also be employed to create suitably accurate approximations of fluid flow variables for the purposes of engineering analysis. When used in parallel with a meta-modeling approximation, a closed-form approximation can provide useful feedback concerning proper construction, suitability, or even necessity of an offline approximation tool. It also provides a short-circuit pathway for further reducing the overall computational demands of a fluid flow analysis, again freeing resources for otherwise unsuitable resource expenditures. To validate these inferences, a design optimization problem was presented requiring the inexpensive estimation of aerodynamic forces applied to a valve operating on a simulated piston-cylinder heat engine. The determination of these forces was to be found using parallel surrogate and exact approximation methods, thus evidencing the comparative

  10. Design of a massively parallel computer using bit serial processing elements

    NASA Technical Reports Server (NTRS)

    Aburdene, Maurice F.; Khouri, Kamal S.; Piatt, Jason E.; Zheng, Jianqing

    1995-01-01

    A 1-bit serial processor designed for a parallel computer architecture is described. This processor is used to develop a massively parallel computational engine, with a single instruction-multiple data (SIMD) architecture. The computer is simulated and tested to verify its operation and to measure its performance for further development.

  11. Information-Limited Parallel Processing in Difficult Heterogeneous Covert Visual Search

    ERIC Educational Resources Information Center

    Dosher, Barbara Anne; Han, Songmei; Lu, Zhong-Lin

    2010-01-01

    Difficult visual search is often attributed to time-limited serial attention operations, although neural computations in the early visual system are parallel. Using probabilistic search models (Dosher, Han, & Lu, 2004) and a full time-course analysis of the dynamics of covert visual search, we distinguish unlimited capacity parallel versus serial…

  12. Parallel processing of Eulerian-Lagrangian, cell-based adaptive method for moving boundary problems

    NASA Astrophysics Data System (ADS)

    Kuan, Chih-Kuang

    In this study, issues and techniques related to the parallel processing of the Eulerian-Lagrangian method for multi-scale moving boundary computation are investigated. The scope of the study consists of the Eulerian approach for field equations, explicit interface-tracking, Lagrangian interface modification and reconstruction algorithms, and a cell-based unstructured adaptive mesh refinement (AMR) in a distributed-memory computation framework. We decomposed the Eulerian domain spatially along with AMR to balance the computational load of solving field equations, which is a primary cost of the entire solver. The Lagrangian domain is partitioned based on marker vicinities with respect to the Eulerian partitions to minimize inter-processor communication. Overall, the performance of an Eulerian task peaks at 10,000-20,000 cells per processor, and it is the upper bound of the performance of the Eulerian- Lagrangian method. Moreover, the load imbalance of the Lagrangian task is not as influential as the communication overhead of the Eulerian-Lagrangian tasks on the overall performance. To assess the parallel processing capabilities, a high Weber number drop collision is simulated. The high convective to viscous length scale ratios result in disparate length scale distributions; together with the moving and topologically irregular interfaces, the computational tasks require temporally and spatially resolved treatment adaptively. The techniques presented enable us to perform original studies to meet such computational requirements. Coalescence, stretch, and break-up of satellite droplets due to the interfacial instability are observed in current study, and the history of interface evolution is in good agreement with the experimental data. The competing mechanisms of the primary and secondary droplet break up, along with the gas-liquid interfacial dynamics are systematically investigated. This study shows that Rayleigh-Taylor instability on the edge of an extruding sheet

  13. Efficient parallel algorithm of second-order Møller-Plesset perturbation theory with resolution-of-identity approximation (RI-MP2)

    NASA Astrophysics Data System (ADS)

    Katouda, Michio; Nagase, Shigeru

    An efficient parallel algorithm is developed for second-order Møller-Plesset perturbation theory with the resolution-of-identity approximation of two-electron repulsion integrals (RI-MP2) to perform MP2 energy calculations of large molecules on distributed memory processors. Benchmark calculations are carried out for taxol (C47H51NO14), valinomycin (C54H90N6O18), and two-layer nanographene sheets (C96H24)2, which show the high parallel efficiency of the developed algorithm.

  14. A new perspective on visual word processing efficiency.

    PubMed

    Houpt, Joseph W; Townsend, James T; Donkin, Christopher

    2014-01-01

    As a fundamental part of our daily lives, visual word processing has received much attention in the psychological literature. Despite the well established advantage of perceiving letters in a word or in a pseudoword over letters alone or in random sequences using accuracy, a comparable effect using response times has been elusive. Some researchers continue to question whether the advantage due to word context is perceptual. We use the capacity coefficient, a well established, response time based measure of efficiency to provide evidence of word processing as a particularly efficient perceptual process to complement those results from the accuracy domain. PMID:24334151

  15. Massively Parallel Geostatistical Inversion of Coupled Processes in Heterogeneous Porous Media

    NASA Astrophysics Data System (ADS)

    Ngo, A.; Schwede, R. L.; Li, W.; Bastian, P.; Ippisch, O.; Cirpka, O. A.

    2012-04-01

    The quasi-linear geostatistical approach is an inversion scheme that can be used to estimate the spatial distribution of a heterogeneous hydraulic conductivity field. The estimated parameter field is considered to be a random variable that varies continuously in space, meets the measurements of dependent quantities (such as the hydraulic head, the concentration of a transported solute or its arrival time) and shows the required spatial correlation (described by certain variogram models). This is a method of conditioning a parameter field to observations. Upon discretization, this results in as many parameters as elements of the computational grid. For a full three dimensional representation of the heterogeneous subsurface it is hardly sufficient to work with resolutions (up to one million parameters) of the model domain that can be achieved on a serial computer. The forward problems to be solved within the inversion procedure consists of the elliptic steady-state groundwater flow equation and the formally elliptic but nearly hyperbolic steady-state advection-dominated solute transport equation in a heterogeneous porous medium. Both equations are discretized by Finite Element Methods (FEM) using fully scalable domain decomposition techniques. Whereas standard conforming FEM is sufficient for the flow equation, for the advection dominated transport equation, which rises well known numerical difficulties at sharp fronts or boundary layers, we use the streamline diffusion approach. The arising linear systems are solved using efficient iterative solvers with an AMG (algebraic multigrid) pre-conditioner. During each iteration step of the inversion scheme one needs to solve a multitude of forward and adjoint problems in order to calculate the sensitivities of each measurement and the related cross-covariance matrix of the unknown parameters and the observations. In order to reduce interprocess communications and to improve the scalability of the code on larger clusters

  16. Optimization of Parallel Legendre Transform using Graphics Processing Unit (GPU) for a Geodynamo Code

    NASA Astrophysics Data System (ADS)

    Lokavarapu, H. V.; Matsui, H.

    2015-12-01

    Convection and magnetic field of the Earth's outer core are expected to have vast length scales. To resolve these flows, high performance computing is required for geodynamo simulations using spherical harmonics transform (SHT), a significant portion of the execution time is spent on the Legendre transform. Calypso is a geodynamo code designed to model magnetohydrodynamics of a Boussinesq fluid in a rotating spherical shell, such as the outer core of the Earth. The code has been shown to scale well on computer clusters capable of computing at the order of 10⁵ cores using Message Passing Interface (MPI) and Open Multi-Processing (OpenMP) parallelization for CPUs. To further optimize, we investigate three different algorithms of the SHT using GPUs. One is to preemptively compute the Legendre polynomials on the CPU before executing SHT on the GPU within the time integration loop. In the second approach, both the Legendre polynomials and the SHT are computed on the GPU simultaneously. In the third approach , we initially partition the radial grid for the forward transform and the harmonic order for the backward transform between the CPU and GPU. There after, the partitioned works are simultaneously computed in the time integration loop. We examine the trade-offs between space and time, memory bandwidth and GPU computations on Maverick, a Texas Advanced Computing Center (TACC) supercomputer. We have observed improved performance using a GPU enabled Legendre transform. Furthermore, we will compare and contrast the different algorithms in the context of GPUs.

  17. Medical ultrasound digital beamforming on a massively parallel processing array platform

    NASA Astrophysics Data System (ADS)

    Chen, Paul; Butts, Mike; Budlong, Brad

    2008-03-01

    Digital beamforming has been widely used in modern medical ultrasound instruments. Flexibility is the key advantage of a digital beamformer over the traditional analog approach. Unlike analog delay lines, digital delay can be programmed to implement new ways of beam shaping and beam steering without hardware modification. Digital beamformers can also be focused dynamically by tracking the depth and focusing the receive beam as the depth increases. By constantly updating an element weight table, a digital beamformer can dynamically increase aperture size with depth to maintain constant lateral resolution and reduce sidelobe noise. Because ultrasound digital beamformers have high I/O bandwidth and processing requirements, traditionally they have been implemented using ASICs or FPGAs that are costly both in time and in money. This paper introduces a sample implementation of a digital beamformer that is programmed in software on a Massively Parallel Processor Array (MPPA). The system consists of a host PC and a PCI Express-based beamformer accelerator with an Ambric Am2045 MPPA chip and 512 Mbytes of external memory. The Am2045 has 336 asynchronous RISCDSP processors that communicate through a configurable structure of channels, using a self-synchronizing communication protocol.

  18. Early parallel processing in reading: a connectionist approach. Technical report, April-November 1986

    SciTech Connect

    Mozer, M.C.

    1986-12-01

    To what extent can information distributed across the visual field be processed in parallel. A connectionist model capable of recognizing multiple words appearing simultaneously on its retina is described that addresses this question. The model relies on the notion of a hierarchy of detectors, starting at the lowest level with position-specific primitive-feature detectors, and progressing to a level composed of position-independent letter cluster detectors. Intervening levels register successively higher-order features and also collapse over local spatial regions of the level below resulting in less positional specificity of the detectors. Using an associative learning rule, the model has been taught to recognize a large sample of words in arbitrary retinal locations. Following this training, it is also able to recognize several words simultaneously, although under certain conditions crosstalk among words can become unmanageable. The model includes an attentional mechanism, which can limit crosstalk, and a serial readout mechanism, which is necessary for a word to reach awareness. While exhaustive simulation experiments have yet to be carried out, there are a variety of phenomena, both experimental and anecdotal, that the model appears well-equipped to account for, including: translation and scale invariant recognition, positional uncertainty at the letter and word levels, the recognition of misspelled words, the integration of information across fixations, similarity-based interference effects, and the role of focal attention in localization.

  19. A Parallel Process Growth Mixture Model of Conduct Problems and Substance Use with Risky Sexual Behavior

    PubMed Central

    Wu, Johnny; Witkiewitz, Katie; McMahon, Robert J.; Dodge, Kenneth A.

    2010-01-01

    Conduct problems, substance use, and risky sexual behavior have been shown to coexist among adolescents, which may lead to significant health problems. The current study was designed to examine relations among these problem behaviors in a community sample of children at high risk for conduct disorder. A latent growth model of childhood conduct problems showed a decreasing trend from grades K to 5. During adolescence, four concurrent conduct problem and substance use trajectory classes were identified (high conduct problems and high substance use, increasing conduct problems and increasing substance use, minimal conduct problems and increasing substance use, and minimal conduct problems and minimal substance use) using a parallel process growth mixture model. Across all substances (tobacco, binge drinking, and marijuana use), higher levels of childhood conduct problems during kindergarten predicted a greater probability of classification into more problematic adolescent trajectory classes relative to less problematic classes. For tobacco and binge drinking models, increases in childhood conduct problems over time also predicted a greater probability of classification into more problematic classes. For all models, individuals classified into more problematic classes showed higher proportions of early sexual intercourse, infrequent condom use, receiving money for sexual services, and ever contracting an STD. Specifically, tobacco use and binge drinking during early adolescence predicted higher levels of sexual risk taking into late adolescence. Results highlight the importance of studying the conjoint relations among conduct problems, substance use, and risky sexual behavior in a unified model. PMID:20558013

  20. Parallel Distributed Processing at 25: further explorations in the microstructure of cognition.

    PubMed

    Rogers, Timothy T; McClelland, James L

    2014-08-01

    This paper introduces a special issue of Cognitive Science initiated on the 25th anniversary of the publication of Parallel Distributed Processing (PDP), a two-volume work that introduced the use of neural network models as vehicles for understanding cognition. The collection surveys the core commitments of the PDP framework, the key issues the framework has addressed, and the debates the framework has spawned, and presents viewpoints on the current status of these issues. The articles focus on both historical roots and contemporary developments in learning, optimality theory, perception, memory, language, conceptual knowledge, cognitive control, and consciousness. Here we consider the approach more generally, reviewing the original motivations, the resulting framework, and the central tenets of the underlying theory. We then evaluate the impact of PDP both on the field at large and within specific subdomains of cognitive science and consider the current role of PDP models within the broader landscape of contemporary theoretical frameworks in cognitive science. Looking to the future, we consider the implications for cognitive science of the recent success of machine learning systems called "deep networks"-systems that build on key ideas presented in the PDP volumes.

  1. Method and apparatus for optimizing the efficiency and quality of laser material processing

    DOEpatents

    Susemihl, I.

    1990-03-13

    The efficiency of laser welding and other laser material processing is optimized according to this invention by rotating the plane of polarization of a linearly polarized laser beam in relation to a work piece of the material being processed simultaneously and in synchronization with steering the laser beam over the work piece so as to keep the plane of polarization parallel to either the plane of incidence or the direction of travel of the beam in relation to the work piece. Also, depending to some extent on the particular processing being accomplished, such as welding or fusing, the angle of incidence of the laser beam on the work piece is kept at or near the polarizing or Brewster's angle. The combination of maintaining the plane of polarization parallel to plane of incidence while also maintaining the angle of incidence at or near the polarizing or Brewster's angle results in only minimal, if any, reflection losses during laser welding. Also, coordinating rotation of the plane of polarization with the translation or steering of a work piece under a laser cutting beam maximizes efficiency and kerf geometry, regardless of the direction of cut. 7 figs.

  2. Method and apparatus for optimizing the efficiency and quality of laser material processing

    DOEpatents

    Susemihl, Ingo

    1990-01-01

    The efficiency of laser welding and other laser material processing is optimized according to this invention by rotating the plane of polarization of a linearly polarized laser beam in relation to a work piece of the material being processed simultaneously and in synchronization with steering the laser beam over the work piece so as to keep the plane of polarization parallel to either the plane of incidence or the direction of travel of the beam in relation to the work piece. Also, depending to some extent on the particular processing being accomplished, such as welding or fusing, the angle of incidence of the laser beam on the work piece is kept at or near the polarizing or Brewster's angle. The combination of maintaining the plane of polarization parallel to plane of incidence while also maintaining the angle of incidence at or near the polarizing or Brewster's angle results in only minimal, if any, reflection losses during laser welding. Also, coordinating rotation of the plane of polarization with the translation or steering of a work piece under a laser cutting beam maximizes efficiency and kerf geometry, regardless of the direction of cut.

  3. Efficient sampling of protein conformational space using fast loop building and batch minimization on highly parallel computers.

    PubMed

    Tyka, Michael D; Jung, Kenneth; Baker, David

    2012-12-01

    All-atom sampling is a critical and compute-intensive end stage to protein structural modeling. Because of the vast size and extreme ruggedness of conformational space, even close to the native structure, the high-resolution sampling problem is almost as difficult as predicting the rough fold of a protein. Here, we present a combination of new algorithms that considerably speed up the exploration of very rugged conformational landscapes and are capable of finding heretofore hidden low-energy states. The algorithm is based on a hierarchical workflow and can be parallelized on supercomputers with up to 128,000 compute cores with near perfect efficiency. Such scaling behavior is notable, as with Moore's law continuing only in the number of cores per chip, parallelizability is a critical property of new algorithms. Using the enhanced sampling power, we have uncovered previously invisible deficiencies in the Rosetta force field and created an extensive decoy training set for optimizing and testing force fields. PMID:22847521

  4. High efficiency integration of three-dimensional functional microdevices inside a microfluidic chip by using femtosecond laser multifoci parallel microfabrication.

    PubMed

    Xu, Bing; Du, Wen-Qiang; Li, Jia-Wen; Hu, Yan-Lei; Yang, Liang; Zhang, Chen-Chu; Li, Guo-Qiang; Lao, Zhao-Xin; Ni, Jin-Cheng; Chu, Jia-Ru; Wu, Dong; Liu, Su-Ling; Sugioka, Koji

    2016-01-01

    High efficiency fabrication and integration of three-dimension (3D) functional devices in Lab-on-a-chip systems are crucial for microfluidic applications. Here, a spatial light modulator (SLM)-based multifoci parallel femtosecond laser scanning technology was proposed to integrate microstructures inside a given 'Y' shape microchannel. The key novelty of our approach lies on rapidly integrating 3D microdevices inside a microchip for the first time, which significantly reduces the fabrication time. The high quality integration of various 2D-3D microstructures was ensured by quantitatively optimizing the experimental conditions including prebaking time, laser power and developing time. To verify the designable and versatile capability of this method for integrating functional 3D microdevices in microchannel, a series of microfilters with adjustable pore sizes from 12.2 μm to 6.7 μm were fabricated to demonstrate selective filtering of the polystyrene (PS) particles and cancer cells with different sizes. The filter can be cleaned by reversing the flow and reused for many times. This technology will advance the fabrication technique of 3D integrated microfluidic and optofluidic chips.

  5. High efficiency integration of three-dimensional functional microdevices inside a microfluidic chip by using femtosecond laser multifoci parallel microfabrication

    PubMed Central

    Xu, Bing; Du, Wen-Qiang; Li, Jia-Wen; Hu, Yan-Lei; Yang, Liang; Zhang, Chen-Chu; Li, Guo-Qiang; Lao, Zhao-Xin; Ni, Jin-Cheng; Chu, Jia-Ru; Wu, Dong; Liu, Su-Ling; Sugioka, Koji

    2016-01-01

    High efficiency fabrication and integration of three-dimension (3D) functional devices in Lab-on-a-chip systems are crucial for microfluidic applications. Here, a spatial light modulator (SLM)-based multifoci parallel femtosecond laser scanning technology was proposed to integrate microstructures inside a given ‘Y’ shape microchannel. The key novelty of our approach lies on rapidly integrating 3D microdevices inside a microchip for the first time, which significantly reduces the fabrication time. The high quality integration of various 2D-3D microstructures was ensured by quantitatively optimizing the experimental conditions including prebaking time, laser power and developing time. To verify the designable and versatile capability of this method for integrating functional 3D microdevices in microchannel, a series of microfilters with adjustable pore sizes from 12.2 μm to 6.7 μm were fabricated to demonstrate selective filtering of the polystyrene (PS) particles and cancer cells with different sizes. The filter can be cleaned by reversing the flow and reused for many times. This technology will advance the fabrication technique of 3D integrated microfluidic and optofluidic chips. PMID:26818119

  6. High efficiency integration of three-dimensional functional microdevices inside a microfluidic chip by using femtosecond laser multifoci parallel microfabrication

    NASA Astrophysics Data System (ADS)

    Xu, Bing; Du, Wen-Qiang; Li, Jia-Wen; Hu, Yan-Lei; Yang, Liang; Zhang, Chen-Chu; Li, Guo-Qiang; Lao, Zhao-Xin; Ni, Jin-Cheng; Chu, Jia-Ru; Wu, Dong; Liu, Su-Ling; Sugioka, Koji

    2016-01-01

    High efficiency fabrication and integration of three-dimension (3D) functional devices in Lab-on-a-chip systems are crucial for microfluidic applications. Here, a spatial light modulator (SLM)-based multifoci parallel femtosecond laser scanning technology was proposed to integrate microstructures inside a given ‘Y’ shape microchannel. The key novelty of our approach lies on rapidly integrating 3D microdevices inside a microchip for the first time, which significantly reduces the fabrication time. The high quality integration of various 2D-3D microstructures was ensured by quantitatively optimizing the experimental conditions including prebaking time, laser power and developing time. To verify the designable and versatile capability of this method for integrating functional 3D microdevices in microchannel, a series of microfilters with adjustable pore sizes from 12.2 μm to 6.7 μm were fabricated to demonstrate selective filtering of the polystyrene (PS) particles and cancer cells with different sizes. The filter can be cleaned by reversing the flow and reused for many times. This technology will advance the fabrication technique of 3D integrated microfluidic and optofluidic chips.

  7. High efficiency integration of three-dimensional functional microdevices inside a microfluidic chip by using femtosecond laser multifoci parallel microfabrication.

    PubMed

    Xu, Bing; Du, Wen-Qiang; Li, Jia-Wen; Hu, Yan-Lei; Yang, Liang; Zhang, Chen-Chu; Li, Guo-Qiang; Lao, Zhao-Xin; Ni, Jin-Cheng; Chu, Jia-Ru; Wu, Dong; Liu, Su-Ling; Sugioka, Koji

    2016-01-01

    High efficiency fabrication and integration of three-dimension (3D) functional devices in Lab-on-a-chip systems are crucial for microfluidic applications. Here, a spatial light modulator (SLM)-based multifoci parallel femtosecond laser scanning technology was proposed to integrate microstructures inside a given 'Y' shape microchannel. The key novelty of our approach lies on rapidly integrating 3D microdevices inside a microchip for the first time, which significantly reduces the fabrication time. The high quality integration of various 2D-3D microstructures was ensured by quantitatively optimizing the experimental conditions including prebaking time, laser power and developing time. To verify the designable and versatile capability of this method for integrating functional 3D microdevices in microchannel, a series of microfilters with adjustable pore sizes from 12.2 μm to 6.7 μm were fabricated to demonstrate selective filtering of the polystyrene (PS) particles and cancer cells with different sizes. The filter can be cleaned by reversing the flow and reused for many times. This technology will advance the fabrication technique of 3D integrated microfluidic and optofluidic chips. PMID:26818119

  8. Stochastic dynamics of small ensembles of non-processive molecular motors: The parallel cluster model

    NASA Astrophysics Data System (ADS)

    Erdmann, Thorsten; Albert, Philipp J.; Schwarz, Ulrich S.

    2013-11-01

    Non-processive molecular motors have to work together in ensembles in order to generate appreciable levels of force or movement. In skeletal muscle, for example, hundreds of myosin II molecules cooperate in thick filaments. In non-muscle cells, by contrast, small groups with few tens of non-muscle myosin II motors contribute to essential cellular processes such as transport, shape changes, or mechanosensing. Here we introduce a detailed and analytically tractable model for this important situation. Using a three-state crossbridge model for the myosin II motor cycle and exploiting the assumptions of fast power stroke kinetics and equal load sharing between motors in equivalent states, we reduce the stochastic reaction network to a one-step master equation for the binding and unbinding dynamics (parallel cluster model) and derive the rules for ensemble movement. We find that for constant external load, ensemble dynamics is strongly shaped by the catch bond character of myosin II, which leads to an increase of the fraction of bound motors under load and thus to firm attachment even for small ensembles. This adaptation to load results in a concave force-velocity relation described by a Hill relation. For external load provided by a linear spring, myosin II ensembles dynamically adjust themselves towards an isometric state with constant average position and load. The dynamics of the ensembles is now determined mainly by the distribution of motors over the different kinds of bound states. For increasing stiffness of the external spring, there is a sharp transition beyond which myosin II can no longer perform the power stroke. Slow unbinding from the pre-power-stroke state protects the ensembles against detachment.

  9. Parallel processing across neural systems: implications for a multiple memory system hypothesis.

    PubMed

    Mizumori, Sheri J Y; Yeshenko, Oksana; Gill, Kathryn M; Davis, Denise M

    2004-11-01

    A common conceptualization of the organization of memory systems in brain is that different types of memory are mediated by distinct neural systems. Strong support for this view comes from studies that show double (or triple) dissociations between spatial, response, and emotional memories following selective lesions of hippocampus, striatum, and the amygdala. Here, we examine the extent to which hippocampal and striatal neural activity patterns support the multiple memory systems view. A comparison is made between hippocampal and striatal neural correlates with behavior during asymptotic performance of spatial and response maze tasks. Location- (or place), movement, and reward-specific firing patterns were found in both structures regardless of the task demands. Many, but not all, place fields of hippocampal and striatal neurons were similarly affected by changes in the visual and reward context regardless of the cognitive demands. Also, many, but not all, hippocampal and striatal movement-sensitive neurons showed significant changes in their behavioral correlates after a change in visual context, irrespective of cognitive strategy. Similar partial reorganization was observed following manipulations of the reward condition for cells recorded from both structures, again regardless of task. Assuming that representations that persist across context changes reflect learned information, we make the following conclusions. First, the consistent pattern of partial reorganization supports a view that the analysis of spatial, response, and reinforcement information is accomplished via an error-driven, or match-mismatch, algorithm across neural systems. Second, task-relevant processing occurs continuously within hippocampus and striatum regardless of the cognitive demands of the task. Third, given the high degree of parallel processing across allegedly different memory systems, we propose that different neural systems may effectively compete for control of a behavioral

  10. Stochastic dynamics of small ensembles of non-processive molecular motors: The parallel cluster model

    SciTech Connect

    Erdmann, Thorsten; Albert, Philipp J.; Schwarz, Ulrich S.

    2013-11-07

    Non-processive molecular motors have to work together in ensembles in order to generate appreciable levels of force or movement. In skeletal muscle, for example, hundreds of myosin II molecules cooperate in thick filaments. In non-muscle cells, by contrast, small groups with few tens of non-muscle myosin II motors contribute to essential cellular processes such as transport, shape changes, or mechanosensing. Here we introduce a detailed and analytically tractable model for this important situation. Using a three-state crossbridge model for the myosin II motor cycle and exploiting the assumptions of fast power stroke kinetics and equal load sharing between motors in equivalent states, we reduce the stochastic reaction network to a one-step master equation for the binding and unbinding dynamics (parallel cluster model) and derive the rules for ensemble movement. We find that for constant external load, ensemble dynamics is strongly shaped by the catch bond character of myosin II, which leads to an increase of the fraction of bound motors under load and thus to firm attachment even for small ensembles. This adaptation to load results in a concave force-velocity relation described by a Hill relation. For external load provided by a linear spring, myosin II ensembles dynamically adjust themselves towards an isometric state with constant average position and load. The dynamics of the ensembles is now determined mainly by the distribution of motors over the different kinds of bound states. For increasing stiffness of the external spring, there is a sharp transition beyond which myosin II can no longer perform the power stroke. Slow unbinding from the pre-power-stroke state protects the ensembles against detachment.

  11. Reconstruction for time-domain in vivo EPR 3D multigradient oximetric imaging--a parallel processing perspective.

    PubMed

    Dharmaraj, Christopher D; Thadikonda, Kishan; Fletcher, Anthony R; Doan, Phuc N; Devasahayam, Nallathamby; Matsumoto, Shingo; Johnson, Calvin A; Cook, John A; Mitchell, James B; Subramanian, Sankaran; Krishna, Murali C

    2009-01-01

    Three-dimensional Oximetric Electron Paramagnetic Resonance Imaging using the Single Point Imaging modality generates unpaired spin density and oxygen images that can readily distinguish between normal and tumor tissues in small animals. It is also possible with fast imaging to track the changes in tissue oxygenation in response to the oxygen content in the breathing air. However, this involves dealing with gigabytes of data for each 3D oximetric imaging experiment involving digital band pass filtering and background noise subtraction, followed by 3D Fourier reconstruction. This process is rather slow in a conventional uniprocessor system. This paper presents a parallelization framework using OpenMP runtime support and parallel MATLAB to execute such computationally intensive programs. The Intel compiler is used to develop a parallel C++ code based on OpenMP. The code is executed on four Dual-Core AMD Opteron shared memory processors, to reduce the computational burden of the filtration task significantly. The results show that the parallel code for filtration has achieved a speed up factor of 46.66 as against the equivalent serial MATLAB code. In addition, a parallel MATLAB code has been developed to perform 3D Fourier reconstruction. Speedup factors of 4.57 and 4.25 have been achieved during the reconstruction process and oximetry computation, for a data set with 23 x 23 x 23 gradient steps. The execution time has been computed for both the serial and parallel implementations using different dimensions of the data and presented for comparison. The reported system has been designed to be easily accessible even from low-cost personal computers through local internet (NIHnet). The experimental results demonstrate that the parallel computing provides a source of high computational power to obtain biophysical parameters from 3D EPR oximetric imaging, almost in real-time.

  12. Distinct lateral inhibitory circuits drive parallel processing of sensory information in the mammalian olfactory bulb.

    PubMed

    Geramita, Matthew A; Burton, Shawn D; Urban, Nathan N

    2016-01-01

    Splitting sensory information into parallel pathways is a common strategy in sensory systems. Yet, how circuits in these parallel pathways are composed to maintain or even enhance the encoding of specific stimulus features is poorly understood. Here, we have investigated the parallel pathways formed by mitral and tufted cells of the olfactory system in mice and characterized the emergence of feature selectivity in these cell types via distinct lateral inhibitory circuits. We find differences in activity-dependent lateral inhibition between mitral and tufted cells that likely reflect newly described differences in the activation of deep and superficial granule cells. Simulations show that these circuit-level differences allow mitral and tufted cells to best discriminate odors in separate concentration ranges, indicating that segregating information about different ranges of stimulus intensity may be an important function of these parallel sensory pathways.

  13. Distinct lateral inhibitory circuits drive parallel processing of sensory information in the mammalian olfactory bulb.

    PubMed

    Geramita, Matthew A; Burton, Shawn D; Urban, Nathan N

    2016-01-01

    Splitting sensory information into parallel pathways is a common strategy in sensory systems. Yet, how circuits in these parallel pathways are composed to maintain or even enhance the encoding of specific stimulus features is poorly understood. Here, we have investigated the parallel pathways formed by mitral and tufted cells of the olfactory system in mice and characterized the emergence of feature selectivity in these cell types via distinct lateral inhibitory circuits. We find differences in activity-dependent lateral inhibition between mitral and tufted cells that likely reflect newly described differences in the activation of deep and superficial granule cells. Simulations show that these circuit-level differences allow mitral and tufted cells to best discriminate odors in separate concentration ranges, indicating that segregating information about different ranges of stimulus intensity may be an important function of these parallel sensory pathways. PMID:27351103

  14. The fast multipole method on parallel clusters, multicore processors, and graphics processing units

    NASA Astrophysics Data System (ADS)

    Darve, Eric; Cecka, Cris; Takahashi, Toru

    2011-02-01

    In this article, we discuss how the fast multipole method (FMM) can be implemented on modern parallel computers, ranging from computer clusters to multicore processors and graphics cards (GPU). The FMM is a somewhat difficult application for parallel computing because of its tree structure and the fact that it requires many complex operations which are not regularly structured. Computational linear algebra with dense matrices for example allows many optimizations that leverage the regular computation pattern. FMM can be similarly optimized but we will see that the complexity of the optimization steps is greater. The discussion will start with a general presentation of FMMs. We briefly discuss parallel methods for the FMM, such as building the FMM tree in parallel, and reducing communication during the FMM procedure. Finally, we will focus on porting and optimizing the FMM on GPUs.

  15. Distinct lateral inhibitory circuits drive parallel processing of sensory information in the mammalian olfactory bulb

    PubMed Central

    Geramita, Matthew A; Burton, Shawn D; Urban, Nathan N

    2016-01-01

    Splitting sensory information into parallel pathways is a common strategy in sensory systems. Yet, how circuits in these parallel pathways are composed to maintain or even enhance the encoding of specific stimulus features is poorly understood. Here, we have investigated the parallel pathways formed by mitral and tufted cells of the olfactory system in mice and characterized the emergence of feature selectivity in these cell types via distinct lateral inhibitory circuits. We find differences in activity-dependent lateral inhibition between mitral and tufted cells that likely reflect newly described differences in the activation of deep and superficial granule cells. Simulations show that these circuit-level differences allow mitral and tufted cells to best discriminate odors in separate concentration ranges, indicating that segregating information about different ranges of stimulus intensity may be an important function of these parallel sensory pathways. DOI: http://dx.doi.org/10.7554/eLife.16039.001 PMID:27351103

  16. Transcranial direct current stimulation modulates efficiency of reading processes.

    PubMed

    Thomson, Jennifer M; Doruk, Deniz; Mascio, Bryan; Fregni, Felipe; Cerruti, Carlo

    2015-01-01

    Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that offers promise as an investigative method for understanding complex cognitive operations such as reading. This study explores the ability of a single session of tDCS to modulate reading efficiency and phonological processing performance within a group of healthy adults. Half the group received anodal or cathodal stimulation, on two separate days, of the left temporo-parietal junction while the other half received anodal or cathodal stimulation of the right homologue area. Pre- and post-stimulation assessment of reading efficiency and phonological processing was carried out. A larger pre-post difference in reading efficiency was found for participants who received right anodal stimulation compared to participants who received left anodal stimulation. Further, there was a significant post-stimulation increase in phonological processing speed following right hemisphere anodal stimulation. Implications for models of reading and reading impairment are discussed.

  17. Greater efficiency in attentional processing related to mindfulness meditation.

    PubMed

    van den Hurk, Paul A M; Giommi, Fabio; Gielen, Stan C; Speckens, Anne E M; Barendregt, Henk P

    2010-06-01

    In this study, attentional processing in relation to mindfulness meditation was investigated. Since recent studies have suggested that mindfulness meditation may induce improvements in attentional processing, we have tested 20 expert mindfulness meditators in the attention network test. Their performance was compared to that of 20 age- and gender-matched controls. In addition to attentional network analyses, overall attentional processing was analysed by means of efficiency scores (i.e., accuracy controlled for reaction time). Better orienting and executive attention (reflected by smaller differences in either reaction time or error score, respectively) were observed in the mindfulness meditation group. Furthermore, extensive mindfulness meditation appeared to be related to a reduction of the fraction of errors for responses with the same reaction time. These results provide new insights into differences in attentional processing related to mindfulness meditation and suggest the possibility of increasing the efficiency in attentional processing by extensive mental training.

  18. Applications of Parallel Process HiMAP for Large Scale Multidisciplinary Problems

    NASA Technical Reports Server (NTRS)

    Guruswamy, Guru P.; Potsdam, Mark; Rodriguez, David; Kwak, Dochay (Technical Monitor)

    2000-01-01

    HiMAP is a three level parallel middleware that can be interfaced to a large scale global design environment for code independent, multidisciplinary analysis using high fidelity equations. Aerospace technology needs are rapidly changing. Computational tools compatible with the requirements of national programs such as space transportation are needed. Conventional computation tools are inadequate for modern aerospace design needs. Advanced, modular computational tools are needed, such as those that incorporate the technology of massively parallel processors (MPP).

  19. Object-processing neural efficiency differentiates object from spatial visualizers.

    PubMed

    Motes, Michael A; Malach, Rafael; Kozhevnikov, Maria

    2008-11-19

    The visual system processes object properties and spatial properties in distinct subsystems, and we hypothesized that this distinction might extend to individual differences in visual processing. We conducted a functional MRI study investigating the neural underpinnings of individual differences in object versus spatial visual processing. Nine participants of high object-processing ability ('object' visualizers) and eight participants of high spatial-processing ability ('spatial' visualizers) were scanned, while they performed an object-processing task. Object visualizers showed lower bilateral neural activity in lateral occipital complex and lower right-lateralized neural activity in dorsolateral prefrontal cortex. The data indicate that high object-processing ability is associated with more efficient use of visual-object resources, resulting in less neural activity in the object-processing pathway.

  20. Parallel versus Serial Processing Dependencies in the Perisylvian Speech Network: A Granger Analysis of Intracranial EEG Data

    ERIC Educational Resources Information Center

    Gow, David W., Jr.; Keller, Corey J.; Eskandar, Emad; Meng, Nate; Cash, Sydney S.

    2009-01-01

    In this work, we apply Granger causality analysis to high spatiotemporal resolution intracranial EEG (iEEG) data to examine how different components of the left perisylvian language network interact during spoken language perception. The specific focus is on the characterization of serial versus parallel processing dependencies in the dominant…

  1. Testing the Theoretical Design of a Health Risk Message: Reexamining the Major Tenets of the Extended Parallel Process Model

    ERIC Educational Resources Information Center

    Gore, Thomas D.; Bracken, Cheryl Campanella

    2005-01-01

    This study examined the fear control/danger control responses that are predicted by the Extended Parallel Process Model (EPPM). In a campaign designed to inform college students about the symptoms and dangers of meningitis, participants were given either a high-threat/no-efficacy or high-efficacy/no-threat health risk message, thus testing the…

  2. SLAPP: A systolic linear algebra parallel processor

    SciTech Connect

    Drake, B.L.; Luk, F.T.; Speiser, J.M.; Symanski, J.J.

    1987-07-01

    Systolic array computer architectures provide a means for fast computation of the linear algebra algorithms that form the building blocks of many signal-processing algorithms, facilitating their real-time computation. For applications to signal processing, the systolic array operates on matrices, an inherently parallel view of the data, using numerical linear algebra algorithms that have been suitably parallelized to efficiently utilize the available hardware. This article describes work currently underway at the Naval Ocean Systems Center, San Diego, California, to build a two-dimensional systolic array, SLAPP, demonstrating efficient and modular parallelization of key matric computations for real-time signal- and image-processing problems.

  3. Parallel Subconvolution Filtering Architectures

    NASA Technical Reports Server (NTRS)

    Gray, Andrew A.

    2003-01-01

    These architectures are based on methods of vector processing and the discrete-Fourier-transform/inverse-discrete- Fourier-transform (DFT-IDFT) overlap-and-save method, combined with time-block separation of digital filters into frequency-domain subfilters implemented by use of sub-convolutions. The parallel-processing method implemented in these architectures enables the use of relatively small DFT-IDFT pairs, while filter tap lengths are theoretically unlimited. The size of a DFT-IDFT pair is determined by the desired reduction in processing rate, rather than on the order of the filter that one seeks to implement. The emphasis in this report is on those aspects of the underlying theory and design rules that promote computational efficiency, parallel processing at reduced data rates, and simplification of the designs of very-large-scale integrated (VLSI) circuits needed to implement high-order filters and correlators.

  4. Using Monte Carlo techniques and parallel processing for fragmentation analysis of explosive payloads

    SciTech Connect

    LaFarge, R.A.

    1992-01-01

    Sandia National Laboratories (SNL) launched the Los Alamos National Laboratory (LANL) sponsored ZEST flight test program from the SNL Kauai Test Facility (KTF) in the summer of 1991. The ZEST program had about 255 pounds of high explosive (HE) aboard a Talos-Castor launch vehicle. Naturally, such undertakings raise questions about the safety of personnel and the environment in the event of a premature detonation of the HE. These questions pertain not only to KTF and the island of Kauai but to the neighboring islands as well. The ability to determine realistically P{sub I}, the probability of an explosively generated fragment impacting a given exclusion area, is an important factor in the safety analysis of any flight test involving explosive payloads. Once P{sub I} is known, the casualty expectations C{sub E} can be computed based on local demographics. A set of two computer codes was developed to determine P{sub I} based on computed fragment impacts. One of these codes, SAFETIE1 (Sandia Analysis of FragmEnt TrajectorIEs), computes files of trajectory initial conditions generated in a Monte Carlo sense for a set of n explosions each containing m fragments. These initial condition files are then used to compute trajectories in a parallel processing environment using a local area network (LAN) of 40 Sun workstations. This approach saves the equivalent of 40 hours of Cray YMP time. The other code, SAFETIE2, is a postprocessor that uses an AMEER output file generated by SAFETIE1, to determine how many explosions have at least one fragment in a user defined exclusion area. The average number of fragments per explosion in the exclusion area ({bar N}) is also computed (for C{sub E} considerations). 12 refs.

  5. Parallel processing streams for motor output and sensory prediction during action preparation

    PubMed Central

    Bauer, Markus; Heinze, Hans-Jochen; Haggard, Patrick; Dolan, Raymond J.

    2014-01-01

    Sensory consequences of one's own actions are perceived as less intense than identical, externally generated stimuli. This is generally taken as evidence for sensory prediction of action consequences. Accordingly, recent theoretical models explain this attenuation by an anticipatory modulation of sensory processing prior to stimulus onset (Roussel et al. 2013) or even action execution (Brown et al. 2013). Experimentally, prestimulus changes that occur in anticipation of self-generated sensations are difficult to disentangle from more general effects of stimulus expectation, attention and task load (performing an action). Here, we show that an established manipulation of subjective agency over a stimulus leads to a predictive modulation in sensory cortex that is independent of these factors. We recorded magnetoencephalography while subjects performed a simple action with either hand and judged the loudness of a tone caused by the action. Effector selection was manipulated by subliminal motor priming. Compatible priming is known to enhance a subjective experience of agency over a consequent stimulus (Chambon and Haggard 2012). In line with this effect on subjective agency, we found stronger sensory attenuation when the action that caused the tone was compatibly primed. This perceptual effect was reflected in a transient phase-locked signal in auditory cortex before stimulus onset and motor execution. Interestingly, this sensory signal emerged at a time when the hemispheric lateralization of motor signals in M1 indicated ongoing effector selection. Our findings confirm theoretical predictions of a sensory modulation prior to self-generated sensations and support the idea that a sensory prediction is generated in parallel to motor output (Walsh and Haggard 2010), before an efference copy becomes available. PMID:25540223

  6. Parallel processing streams for motor output and sensory prediction during action preparation.

    PubMed

    Stenner, Max-Philipp; Bauer, Markus; Heinze, Hans-Jochen; Haggard, Patrick; Dolan, Raymond J

    2015-03-15

    Sensory consequences of one's own actions are perceived as less intense than identical, externally generated stimuli. This is generally taken as evidence for sensory prediction of action consequences. Accordingly, recent theoretical models explain this attenuation by an anticipatory modulation of sensory processing prior to stimulus onset (Roussel et al. 2013) or even action execution (Brown et al. 2013). Experimentally, prestimulus changes that occur in anticipation of self-generated sensations are difficult to disentangle from more general effects of stimulus expectation, attention and task load (performing an action). Here, we show that an established manipulation of subjective agency over a stimulus leads to a predictive modulation in sensory cortex that is independent of these factors. We recorded magnetoencephalography while subjects performed a simple action with either hand and judged the loudness of a tone caused by the action. Effector selection was manipulated by subliminal motor priming. Compatible priming is known to enhance a subjective experience of agency over a consequent stimulus (Chambon and Haggard 2012). In line with this effect on subjective agency, we found stronger sensory attenuation when the action that caused the tone was compatibly primed. This perceptual effect was reflected in a transient phase-locked signal in auditory cortex before stimulus onset and motor execution. Interestingly, this sensory signal emerged at a time when the hemispheric lateralization of motor signals in M1 indicated ongoing effector selection. Our findings confirm theoretical predictions of a sensory modulation prior to self-generated sensations and support the idea that a sensory prediction is generated in parallel to motor output (Walsh and Haggard 2010), before an efference copy becomes available.

  7. Motor and perceptual sequence learning: different time course of parallel processes.

    PubMed

    Dirnberger, Georg; Novak-Knollmueller, Judith

    2013-07-10

    The aim was to determine the extent and time course of motor and perceptual learning in a procedural learning task, and the relation of these two processes. Because environmental constraints modulate the relative impact of different learning mechanisms, we chose a simple learning task similar to real-life exercise. Thirty-four healthy individuals performed a visuomotor serial reaction time task. Learning blocks with high stimulus-response compatibility were practiced repeatedly; in between these, participants performed test blocks with the same or a different (mirror-inverted, or new) stimulus sequence and/or with the same or a different (mirror-inverted) stimulus-response allocation. This design allowed us to measure the progress of motor learning and perceptual learning independently. Results showed that in the learning blocks, a steady reduction of the reaction times indicated that - as expected - participants improved their skills continuously. Analysis of the test blocks indicated that both motor learning and perceptual learning were significant. The two mechanisms were correlated (r=0.62, P<0.001). However, their time course was different: the impact of motor learning increased strongly from earlier to later intervals, whereas the progress of perceptual learning was more stable but slower. In conclusion, in a simple visuomotor learning task, participants can learn the motor sequence and the stimulus sequence in parallel. The positive correlation of motor and perceptual learning suggests that the two mechanisms act in synergy and are not alternative opposing strategies. The impact of these two learning mechanisms changes over time: motor learning sets in later and becomes relevant only in the course of training.

  8. Improved motion contrast and processing efficiency in OCT angiography using complex-correlation algorithm

    NASA Astrophysics Data System (ADS)

    Guo, Li; Li, Pei; Pan, Cong; Liao, Rujia; Cheng, Yuxuan; Hu, Weiwei; Chen, Zhong; Ding, Zhihua; Li, Peng

    2016-02-01

    The complex-based OCT angiography (Angio-OCT) offers high motion contrast by combining both the intensity and phase information. However, due to involuntary bulk tissue motions, complex-valued OCT raw data are processed sequentially with different algorithms for correcting bulk image shifts (BISs), compensating global phase fluctuations (GPFs) and extracting flow signals. Such a complicated procedure results in massive computational load. To mitigate such a problem, in this work, we present an inter-frame complex-correlation (CC) algorithm. The CC algorithm is suitable for parallel processing of both flow signal extraction and BIS correction, and it does not need GPF compensation. This method provides high processing efficiency and shows superiority in motion contrast. The feasibility and performance of the proposed CC algorithm is demonstrated using both flow phantom and live animal experiments.

  9. Processes for producing low cost, high efficiency silicon solar cells

    DOEpatents

    Rohatgi, Ajeet; Doshi, Parag; Tate, John Keith; Mejia, Jose; Chen, Zhizhang

    1998-06-16

    Processes which utilize rapid thermal processing (RTP) are provided for inexpensively producing high efficiency silicon solar cells. The RTP processes preserve minority carrier bulk lifetime .tau. and permit selective adjustment of the depth of the diffused regions, including emitter and back surface field (bsf), within the silicon substrate. In a first RTP process, an RTP step is utilized to simultaneously diffuse phosphorus and aluminum into the front and back surfaces, respectively, of a silicon substrate. Moreover, an in situ controlled cooling procedure preserves the carrier bulk lifetime .tau. and permits selective adjustment of the depth of the diffused regions. In a second RTP process, both simultaneous diffusion of the phosphorus and aluminum as well as annealing of the front and back contacts are accomplished during the RTP step. In a third RTP process, the RTP step accomplishes simultaneous diffusion of the phosphorus and aluminum, annealing of the contacts, and annealing of a double-layer antireflection/passivation coating SiN/SiO.sub.x. In a fourth RTP process, the process of applying front and back contacts is broken up into two separate respective steps, which enhances the efficiency of the cells, at a slight time expense. In a fifth RTP process, a second RTP step is utilized to fire and adhere the screen printed or evaporated contacts to the structure.

  10. Processes for producing low cost, high efficiency silicon solar cells

    DOEpatents

    Rohatgi, A.; Doshi, P.; Tate, J.K.; Mejia, J.; Chen, Z.

    1998-06-16

    Processes which utilize rapid thermal processing (RTP) are provided for inexpensively producing high efficiency silicon solar cells. The RTP processes preserve minority carrier bulk lifetime {tau} and permit selective adjustment of the depth of the diffused regions, including emitter and back surface field (bsf), within the silicon substrate. In a first RTP process, an RTP step is utilized to simultaneously diffuse phosphorus and aluminum into the front and back surfaces, respectively, of a silicon substrate. Moreover, an in situ controlled cooling procedure preserves the carrier bulk lifetime {tau} and permits selective adjustment of the depth of the diffused regions. In a second RTP process, both simultaneous diffusion of the phosphorus and aluminum as well as annealing of the front and back contacts are accomplished during the RTP step. In a third RTP process, the RTP step accomplishes simultaneous diffusion of the phosphorus and aluminum, annealing of the contacts, and annealing of a double-layer antireflection/passivation coating SiN/SiO{sub x}. In a fourth RTP process, the process of applying front and back contacts is broken up into two separate respective steps, which enhances the efficiency of the cells, at a slight time expense. In a fifth RTP process, a second RTP step is utilized to fire and adhere the screen printed or evaporated contacts to the structure. 28 figs.

  11. Maximizing the efficiency of multienzyme process by stoichiometry optimization.

    PubMed

    Dvorak, Pavel; Kurumbang, Nagendra P; Bendl, Jaroslav; Brezovsky, Jan; Prokop, Zbynek; Damborsky, Jiri

    2014-09-01

    Multienzyme processes represent an important area of biocatalysis. Their efficiency can be enhanced by optimization of the stoichiometry of the biocatalysts. Here we present a workflow for maximizing the efficiency of a three-enzyme system catalyzing a five-step chemical conversion. Kinetic models of pathways with wild-type or engineered enzymes were built, and the enzyme stoichiometry of each pathway was optimized. Mathematical modeling and one-pot multienzyme experiments provided detailed insights into pathway dynamics, enabled the selection of a suitable engineered enzyme, and afforded high efficiency while minimizing biocatalyst loadings. Optimizing the stoichiometry in a pathway with an engineered enzyme reduced the total biocatalyst load by an impressive 56 %. Our new workflow represents a broadly applicable strategy for optimizing multienzyme processes.

  12. Numerical Processing Efficiency Improved in Experienced Mental Abacus Children

    ERIC Educational Resources Information Center

    Wang, Yunqi; Geng, Fengji; Hu, Yuzheng; Du, Fenglei; Chen, Feiyan

    2013-01-01

    Experienced mental abacus (MA) users are able to perform mental arithmetic calculations with unusual speed and accuracy. However, it remains unclear whether their extraordinary gains in mental arithmetic ability are accompanied by an improvement in numerical processing efficiency. To address this question, the present study, using a numerical…

  13. IMPROVING TACONITE PROCESSING PLANT EFFICIENCY BY COMPUTER SIMULATION, Final Report

    SciTech Connect

    William M. Bond; Salih Ersayin

    2007-03-30

    This project involved industrial scale testing of a mineral processing simulator to improve the efficiency of a taconite processing plant, namely the Minorca mine. The Concentrator Modeling Center at the Coleraine Minerals Research Laboratory, University of Minnesota Duluth, enhanced the capabilities of available software, Usim Pac, by developing mathematical models needed for accurate simulation of taconite plants. This project provided funding for this technology to prove itself in the industrial environment. As the first step, data representing existing plant conditions were collected by sampling and sample analysis. Data were then balanced and provided a basis for assessing the efficiency of individual devices and the plant, and also for performing simulations aimed at improving plant efficiency. Performance evaluation served as a guide in developing alternative process strategies for more efficient production. A large number of computer simulations were then performed to quantify the benefits and effects of implementing these alternative schemes. Modification of makeup ball size was selected as the most feasible option for the target performance improvement. This was combined with replacement of existing hydrocyclones with more efficient ones. After plant implementation of these modifications, plant sampling surveys were carried out to validate findings of the simulation-based study. Plant data showed very good agreement with the simulated data, confirming results of simulation. After the implementation of modifications in the plant, several upstream bottlenecks became visible. Despite these bottlenecks limiting full capacity, concentrator energy improvement of 7% was obtained. Further improvements in energy efficiency are expected in the near future. The success of this project demonstrated the feasibility of a simulation-based approach. Currently, the Center provides simulation-based service to all the iron ore mining companies operating in northern

  14. Parallel processing of information about location in the amygdala, entorhinal cortex and hippocampus.

    PubMed

    Gaskin, Stephane; White, Norman M

    2013-11-01

    The conditioned cue preference paradigm was used to study how rats use extra-maze cues to discriminate between 2 adjacent arms on an 8-arm radial maze, a situation in which most of the same cues can be seen from both arms but only one arm contains food. Since the food-restricted rats eat while passively confined on the food-paired arm no responses are reinforced, so the discrimination is due to Pavlovian stimulus-reward (or outcome) learning. Consistent with other evidence that rats must move around in an environment to acquire a spatial map, we found that learning the adjacent arms CCP (ACCP) required a minimum amount of active exploration of the maze with no reinforcers present prior to passive pairing of the extra-maze cues with the food reinforcer, an instance of latent learning. Temporary inactivation of the hippocampus during the pre-exposure sessions had no effect on ACCP learning, confirming other evidence that the hippocampus is not involved in latent learning. A series of experiments indentified a circuit involving fimbria-fornix and dorsal entorhinal cortex as the neural basis of latent learning in this situation. In contrast, temporary inactivation of the entorhinal cortex or hippocampus during passive training or during testing blocked ACCP learning and expression, respectively, suggesting that these two structures co-operate in using spatial information to learn the location of food on the maze during passive pairing and to express this combined information during testing. In parallel with these processes we found that the amygdala processes information leading to an equal tendency to enter both adjacent arms (even though only one was paired with food) suggesting that the stimulus information available to this structure is not sufficiently precise to discriminate between the ambiguous cues visible from the adjacent arms. Expression of the ACCP in normal rats depends on hippocampus-based learning to avoid the unpaired arm which competes with the

  15. A parallel real-time computing-cluster implementation of spotlight SAR processing

    NASA Astrophysics Data System (ADS)

    Mathew, Bipin; Rabinkin, Daniel

    2005-05-01

    The high resolution imaging capability of Synthetic Aperture Radar (SAR) is largely unaffected by atmospheric conditions and has proven to be an indispensable asset in a variety of military and civilian applications. Application of SAR methodology for real-time imaging however carries with it the large computational complexity and storage requirements of the image-forming algorithms. Recently however, the rapidly diminishing cost of computing hardware and the related ascent of cluster-based computing, has made parallelization of these algorithms an appealing area of investigation. This paper describes a parallel SAR processor developed at MIT Lincoln Laboratory. Several novel technologies were employed in it's implementation, including pMatlab which is a parallel extension of standard Matlab that is also being developed at MIT Lincoln Laboratory. These technologies will be described later in the document. We begin with a brief description of the basic SAR algorithm.

  16. Information-limited parallel processing in difficult heterogeneous covert visual search.

    PubMed

    Dosher, Barbara Anne; Han, Songmei; Lu, Zhong-Lin

    2010-10-01

    Difficult visual search is often attributed to time-limited serial attention operations, although neural computations in the early visual system are parallel. Using probabilistic search models (Dosher, Han, & Lu, 2004) and a full time-course analysis of the dynamics of covert visual search, we distinguish unlimited capacity parallel versus serial search mechanisms. Performance is measured for difficult and error-prone searches among heterogeneous background elements and for easy and accurate searches among homogeneous background elements. Contrary to the claims of time-limited serial attention, searches in heterogeneous backgrounds instead exhibited nearly identical search dynamics for display sizes up to 12 items. A review and new analyses indicate that most difficult as well as easy visual searches operate as an unlimited-capacity parallel analysis over the visual field within a single eye fixation, which suggests limitations in the availability of information, not temporal bottlenecks in analysis or comparison. Serial properties likely reflect overt attention expressed in eye movements.

  17. Increased Efficiencies in the INEEL SAR/TSR/USQ Process

    SciTech Connect

    Cole, N.E.

    2002-05-16

    The Idaho National Engineering and Environmental Laboratory (INEEL) has implemented a number of efficiencies to reduce the time and cost of preparing safety basis documents. The INEEL is continuing to look at other aspects of the safety basis process to identify other efficiencies that can be implemented and remain in compliance with Title 10 Code of Federal Regulations (CFR) Part 830. A six-sigma approach is used to identify areas to improve efficiencies and develop the action plan for implementation of the new process, as applicable. Three improvement processes have been implemented: The first was the development of standardized Documented Safety Analysis (DSA) and technical safety requirement (TSR) documents that all nuclear facilities use, by adding facility-specific details. The second is a material procurement process, which is based on safety systems specified in the individual safety basis documents. The third is a restructuring of the entire safety basis preparation and approval process. Significant savings in time to prepare safety basis document, cost of materials, and total cost of the documents are currently being realized.

  18. Increased Efficiencies in the INEEL SAR/TSR/USQ Process

    SciTech Connect

    Cole, Norman Edward

    2002-06-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) has implemented a number of efficiencies to reduce the time and cost of preparing safety basis documents. The INEEL is continuing to look at other aspects of the safety basis process to identify other efficiencies that can be implemented and remain in compliance with Title 10 Code of Federal Regulations (CFR) Part 830. A six-sigma approach is used to identify areas to improve efficiencies and develop the action plan for implementation of the new process, as applicable. Three improvement processes have been implemented: The first was the development of standardized Documented Safety Analysis (DSA) and technical safety requirement (TSR) documents that all nuclear facilities use, by adding facility-specific details. The second is a material procurement process, which is based on safety systems specified in the individual safety basis documents. The third is a restructuring of the entire safety basis preparation and approval process. Significant savings in time to prepare safety basis document, cost of materials, and total cost of the documents are currently being realized.

  19. Parallel Processing of Numerical Tsunami Simulations on a High Performance Cluster based on the GDAL Library

    NASA Astrophysics Data System (ADS)

    Schroeder, Matthias; Jankowski, Cedric; Hammitzsch, Martin; Wächter, Joachim

    2014-05-01

    Thousands of numerical tsunami simulations allow the computation of inundation and run-up along the coast for vulnerable areas over the time. A so-called Matching Scenario Database (MSDB) [1] contains this large number of simulations in text file format. In order to visualize these wave propagations the scenarios have to be reprocessed automatically. In the TRIDEC project funded by the seventh Framework Programme of the European Union a Virtual Scenario Database (VSDB) and a Matching Scenario Database (MSDB) were established amongst others by the working group of the University of Bologna (UniBo) [1]. One part of TRIDEC was the developing of a new generation of a Decision Support System (DSS) for tsunami Early Warning Systems (TEWS) [2]. A working group of the GFZ German Research Centre for Geosciences was responsible for developing the Command and Control User Interface (CCUI) as central software application which support operator activities, incident management and message disseminations. For the integration and visualization in the CCUI, the numerical tsunami simulations from MSDB must be converted into the shapefiles format. The usage of shapefiles enables a much easier integration into standard Geographic Information Systems (GIS). Since also the CCUI is based on two widely used open source products (GeoTools library and uDig), whereby the integration of shapefiles is provided by these libraries a priori. In this case, for an example area around the Western Iberian margin several thousand tsunami variations were processed. Due to the mass of data only a program-controlled process was conceivable. In order to optimize the computing efforts and operating time the use of an existing GFZ High Performance Computing Cluster (HPC) had been chosen. Thus, a geospatial software was sought after that is capable for parallel processing. The FOSS tool Geospatial Data Abstraction Library (GDAL/OGR) was used to match the coordinates with the wave heights and generates the

  20. Parallel processing of real-time dynamic systems simulation on OSCAR (Optimally SCheduled Advanced multiprocessoR)

    NASA Technical Reports Server (NTRS)

    Kasahara, Hironori; Honda, Hiroki; Narita, Seinosuke

    1989-01-01

    Parallel processing of real-time dynamic systems simulation on a multiprocessor system named OSCAR is presented. In the simulation of dynamic systems, generally, the same calculation are repeated every time step. However, we cannot apply to Do-all or the Do-across techniques for parallel processing of the simulation since there exist data dependencies from the end of an iteration to the beginning of the next iteration and furthermore data-input and data-output are required every sampling time period. Therefore, parallelism inside the calculation required for a single time step, or a large basic block which consists of arithmetic assignment statements, must be used. In the proposed method, near fine grain tasks, each of which consists of one or more floating point operations, are generated to extract the parallelism from the calculation and assigned to processors by using optimal static scheduling at compile time in order to reduce large run time overhead caused by the use of near fine grain tasks. The practicality of the scheme is demonstrated on OSCAR (Optimally SCheduled Advanced multiprocessoR) which has been developed to extract advantageous features of static scheduling algorithms to the maximum extent.

  1. Parallel and serial processing of haptic information in man: effects of parietal lesions on sensorimotor hand function.

    PubMed

    Knecht, S; Kunesch, E; Schnitzler, A

    1996-07-01

    Recent animal studies have shown that there is an evolutionary shift within the order of primates from parallel to serial processing of haptic information. In an attempt to determine whether there is also evidence of serial processing in humans 10 patients with parietal cortical lesions, three patients with subcortical lesions and one patient after hemispherectomy, were examined. Case-by-case and across subject analysis of lesion type, sensorimotor profile and electrophysiological findings showed that in unihemispheric lesions: (a) there is little impairment of thermesthesia, nociception and vibration sense: (b) two-point discrimination and integrity of the N20 somatosensory component are highly correlated; (c) a loss of the N20 component is accompanied by a severe impairment of stereognosis; (d) conversely, in more posterior lesions astereognosis can occur with an intact N20 component; and (e) if the lesion is in the right hemisphere there is frequently impairment of graphesthesia in both hands. These data are taken to indicate serial processing from SI (as evidenced by an intact N20 component) to posterior parietal cortex allowing progressive spatial and temporal integration. In graphesthesia our data suggest an integrative function of the right parietal cortex for both sides of the body. Other sensory qualities like vibration nociception and thermesthesia are apparently processed in a non-serial, probably parallel way involving both hemispheres. The effects of cerebral lesions in our series suggest parallel as well as serial processing of somesthetic information in man underlying the perception of different haptic features.

  2. Parallel processing approach for radiative heat transfer prediction in participating media

    SciTech Connect

    Saltiel, C.; Naraghi, M.H.N. Manhattan College, Riverdale, NY )

    1993-12-01

    A unified matrix formulation for node-to-node-based radiative exchange in isotropically scattering inhomogeneous media is developed using the discrete exchange factor method. Computational implementations of the unified matrix formulation on serial and parallel computers are compared. 15 refs.

  3. Parallel Process Issues for Lesbian and Gay Adoptive Parents and Their Adopted Children

    ERIC Educational Resources Information Center

    Matthews, John D.; Cramer, Elizabeth P.

    2005-01-01

    Gays and lesbians, both single and coupled, are increasingly turning to adoption to create or expand their families. This manuscript specifically addresses the continuing needs of adoptees and adoptive parents by exploring key issues in the life course of gays and lesbians and their adopted children, and identifying potential parallel development…

  4. A partitioned shift-without-invert algorithm to improve parallel eigensolution efficiency in real-space electronic transport

    NASA Astrophysics Data System (ADS)

    Feldman, Baruch; Zhou, Yunkai

    2016-10-01

    We present an eigenspectrum partitioning scheme without inversion for the recently described real-space electronic transport code, TRANSEC. The primary advantage of TRANSEC is its highly parallel algorithm, which enables studying conductance in large systems. The present scheme adds a new source of parallelization, significantly enhancing TRANSEC's parallel scalability, especially for systems with many electrons. In principle, partitioning could enable super-linear parallel speedup, as we demonstrate in calculations within TRANSEC. In practical cases, we report better than five-fold improvement in CPU time and similar improvements in wall time, compared to previously-published large calculations. Importantly, the suggested scheme is relatively simple to implement. It can be useful for general large Hermitian or weakly non-Hermitian eigenvalue problems, whenever relatively accurate inversion via direct or iterative linear solvers is impractical.

  5. Multi-Zone Liquid Thrust Chamber Performance Code with Domain Decomposition for Parallel Processing

    NASA Technical Reports Server (NTRS)

    Navaz, Homayun K.

    2002-01-01

    -equation turbulence model, and two-phase flow. To overcome these limitations, the LTCP code is rewritten to include the multi-zone capability with domain decomposition that makes it suitable for parallel processing, i.e., enabling the code to run every zone or sub-domain on a separate processor. This can reduce the run time by a factor of 6 to 8, depending on the problem.

  6. Parallel algorithm for solving Kepler’s equation on Graphics Processing Units: Application to analysis of Doppler exoplanet searches

    NASA Astrophysics Data System (ADS)

    Ford, Eric B.

    2009-05-01

    We present the results of a highly parallel Kepler equation solver using the Graphics Processing Unit (GPU) on a commercial nVidia GeForce 280GTX and the "Compute Unified Device Architecture" (CUDA) programming environment. We apply this to evaluate a goodness-of-fit statistic (e.g., χ2) for Doppler observations of stars potentially harboring multiple planetary companions (assuming negligible planet-planet interactions). Given the high-dimensionality of the model parameter space (at least five dimensions per planet), a global search is extremely computationally demanding. We expect that the underlying Kepler solver and model evaluator will be combined with a wide variety of more sophisticated algorithms to provide efficient global search, parameter estimation, model comparison, and adaptive experimental design for radial velocity and/or astrometric planet searches. We tested multiple implementations using single precision, double precision, pairs of single precision, and mixed precision arithmetic. We find that the vast majority of computations can be performed using single precision arithmetic, with selective use of compensated summation for increased precision. However, standard single precision is not adequate for calculating the mean anomaly from the time of observation and orbital period when evaluating the goodness-of-fit for real planetary systems and observational data sets. Using all double precision, our GPU code outperforms a similar code using a modern CPU by a factor of over 60. Using mixed precision, our GPU code provides a speed-up factor of over 600, when evaluating nsys > 1024 models planetary systems each containing npl = 4 planets and assuming nobs = 256 observations of each system. We conclude that modern GPUs also offer a powerful tool for repeatedly evaluating Kepler's equation and a goodness-of-fit statistic for orbital models when presented with a large parameter space.

  7. Working memory capacity and redundant information processing efficiency

    PubMed Central

    Endres, Michael J.; Houpt, Joseph W.; Donkin, Chris; Finn, Peter R.

    2015-01-01

    Working memory capacity (WMC) is typically measured by the amount of task-relevant information an individual can keep in mind while resisting distraction or interference from task-irrelevant information. The current research investigated the extent to which differences in WMC were associated with performance on a novel redundant memory probes (RMP) task that systematically varied the amount of to-be-remembered (targets) and to-be-ignored (distractor) information. The RMP task was designed to both facilitate and inhibit working memory search processes, as evidenced by differences in accuracy, response time, and Linear Ballistic Accumulator (LBA) model estimates of information processing efficiency. Participants (N = 170) completed standard intelligence tests and dual-span WMC tasks, along with the RMP task. As expected, accuracy, response-time, and LBA model results indicated memory search and retrieval processes were facilitated under redundant-target conditions, but also inhibited under mixed target/distractor and redundant-distractor conditions. Repeated measures analyses also indicated that, while individuals classified as high (n = 85) and low (n = 85) WMC did not differ in the magnitude of redundancy effects, groups did differ in the efficiency of memory search and retrieval processes overall. Results suggest that redundant information reliably facilitates and inhibits the efficiency or speed of working memory search, and these effects are independent of more general limits and individual differences in the capacity or space of working memory. PMID:26074828

  8. Efficient magnetohydrodynamic simulations on graphics processing units with CUDA

    NASA Astrophysics Data System (ADS)

    Wong, Hon-Cheng; Wong, Un-Hong; Feng, Xueshang; Tang, Zesheng

    2011-10-01

    Magnetohydrodynamic (MHD) simulations based on the ideal MHD equations have become a powerful tool for modeling phenomena in a wide range of applications including laboratory, astrophysical, and space plasmas. In general, high-resolution methods for solving the ideal MHD equations are computationally expensive and Beowulf clusters or even supercomputers are often used to run the codes that implemented these methods. With the advent of the Compute Unified Device Architecture (CUDA), modern graphics processing units (GPUs) provide an alternative approach to parallel computing for scientific simulations. In this paper we present, to the best of the author's knowledge, the first implementation of MHD simulations entirely on GPUs with CUDA, named GPU-MHD, to accelerate the simulation process. GPU-MHD supports both single and double precision computations. A series of numerical tests have been performed to validate the correctness of our code. Accuracy evaluation by comparing single and double precision computation results is also given. Performance measurements of both single and double precision are conducted on both the NVIDIA GeForce GTX 295 (GT200 architecture) and GTX 480 (Fermi architecture) graphics cards. These measurements show that our GPU-based implementation achieves between one and two orders of magnitude of improvement depending on the graphics card used, the problem size, and the precision when comparing to the original serial CPU MHD implementation. In addition, we extend GPU-MHD to support the visualization of the simulation results and thus the whole MHD simulation and visualization process can be performed entirely on GPUs.

  9. Processes for producing low cost, high efficiency silicon solar cells

    DOEpatents

    Rohatgi, Ajeet; Chen, Zhizhang; Doshi, Parag

    1996-01-01

    Processes which utilize rapid thermal processing (RTP) are provided for inexpensively producing high efficiency silicon solar cells. The RTP processes preserve minority carrier bulk lifetime .tau. and permit selective adjustment of the depth of the diffused regions, including emitter and back surface field (bsf), within the silicon substrate. Silicon solar cell efficiencies of 16.9% have been achieved. In a first RTP process, an RTP step is utilized to simultaneously diffuse phosphorus and aluminum into the front and back surfaces, respectively, of a silicon substrate. Moreover, an in situ controlled cooling procedure preserves the carrier bulk lifetime .tau. and permits selective adjustment of the depth of the diffused regions. In a second RTP process, both simultaneous diffusion of the phosphorus and aluminum as well as annealing of the front and back contacts are accomplished during the RTP step. In a third RTP process, the RTP step accomplishes simultaneous diffusion of the phosphorus and aluminum, annealing of the contacts, and annealing of a double-layer antireflection/passivation coating SiN/SiO.sub.x.

  10. Second-Order Møller-Plesset Perturbation Theory in the Condensed Phase: An Efficient and Massively Parallel Gaussian and Plane Waves Approach.

    PubMed

    Del Ben, Mauro; Hutter, Jürg; VandeVondele, Joost

    2012-11-13

    A novel algorithm, based on a hybrid Gaussian and plane waves (GPW) approach, is developed for the canonical second-order Møller-Plesset perturbation energy (MP2) of finite and extended systems. The key aspect of the method is that the electron repulsion integrals (ia|λσ) are computed by direct integration between the products of Gaussian basis functions λσ and the electrostatic potential arising from a given occupied-virtual pair density ia. The electrostatic potential is obtained in a plane waves basis set after solving the Poisson equation in Fourier space. In particular, for condensed phase systems, this scheme is highly efficient. Furthermore, our implementation has low memory requirements and displays excellent parallel scalability up to 100 000 processes. In this way, canonical MP2 calculations for condensed phase systems containing hundreds of atoms or more than 5000 basis functions can be performed within minutes, while systems up to 1000 atoms and 10 000 basis functions remain feasible. Solid LiH has been employed as a benchmark to study basis set and system size convergence. Lattice constants and cohesive energies of various molecular crystals have been studied with MP2 and double-hybrid functionals. PMID:26605583

  11. Nonlinear Memory Capacity of Parallel Time-Delay Reservoir Computers in the Processing of Multidimensional Signals.

    PubMed

    Grigoryeva, Lyudmila; Henriques, Julie; Larger, Laurent; Ortega, Juan-Pablo

    2016-07-01

    This letter addresses the reservoir design problem in the context of delay-based reservoir computers for multidimensional input signals, parallel architectures, and real-time multitasking. First, an approximating reservoir model is presented in those frameworks that provides an explicit functional link between the reservoir architecture and its performance in the execution of a specific task. Second, the inference properties of the ridge regression estimator in the multivariate context are used to assess the impact of finite sample training on the decrease of the reservoir capacity. Finally, an empirical study is conducted that shows the adequacy of the theoretical results with the empirical performances exhibited by various reservoir architectures in the execution of several nonlinear tasks with multidimensional inputs. Our results confirm the robustness properties of the parallel reservoir architecture with respect to task misspecification and parameter choice already documented in the literature.

  12. Nonlinear Memory Capacity of Parallel Time-Delay Reservoir Computers in the Processing of Multidimensional Signals.

    PubMed

    Grigoryeva, Lyudmila; Henriques, Julie; Larger, Laurent; Ortega, Juan-Pablo

    2016-07-01

    This letter addresses the reservoir design problem in the context of delay-based reservoir computers for multidimensional input signals, parallel architectures, and real-time multitasking. First, an approximating reservoir model is presented in those frameworks that provides an explicit functional link between the reservoir architecture and its performance in the execution of a specific task. Second, the inference properties of the ridge regression estimator in the multivariate context are used to assess the impact of finite sample training on the decrease of the reservoir capacity. Finally, an empirical study is conducted that shows the adequacy of the theoretical results with the empirical performances exhibited by various reservoir architectures in the execution of several nonlinear tasks with multidimensional inputs. Our results confirm the robustness properties of the parallel reservoir architecture with respect to task misspecification and parameter choice already documented in the literature. PMID:27172266

  13. Optimized Parallelization for Nonlocal Means Based Low Dose CT Image Processing.

    PubMed

    Zhang, Libo; Yang, Benqiang; Zhuang, Zhikun; Hu, Yining; Chen, Yang; Luo, Limin; Shu, Huazhong

    2015-01-01

    Low dose CT (LDCT) images are often significantly degraded by severely increased mottled noise/artifacts, which can lead to lowered diagnostic accuracy in clinic. The nonlocal means (NLM) filtering can effectively remove mottled noise/artifacts by utilizing large-scale patch similarity information in LDCT images. But the NLM filtering application in LDCT imaging also requires high computation cost because intensive patch similarity calculation within a large searching window is often required to be used to include enough structure-similarity information for noise/artifact suppression. To improve its clinical feasibility, in this study we further optimize the parallelization of NLM filtering by avoiding the repeated computation with the row-wise intensity calculation and the symmetry weight calculation. The shared memory with fast I/O speed is also used in row-wise intensity calculation for the proposed method. Quantitative experiment demonstrates that significant acceleration can be achieved with respect to the traditional straight pixel-wise parallelization.

  14. Efficient maximum likelihood parameterization of continuous-time Markov processes

    PubMed Central

    McGibbon, Robert T.; Pande, Vijay S.

    2015-01-01

    Continuous-time Markov processes over finite state-spaces are widely used to model dynamical processes in many fields of natural and social science. Here, we introduce a maximum likelihood estimator for constructing such models from data observed at a finite time interval. This estimator is dramatically more efficient than prior approaches, enables the calculation of deterministic confidence intervals in all model parameters, and can easily enforce important physical constraints on the models such as detailed balance. We demonstrate and discuss the advantages of these models over existing discrete-time Markov models for the analysis of molecular dynamics simulations. PMID:26203016

  15. Efficiency and toxicity: comparison between the Fenton and electrochemical processes.

    PubMed

    Tavares, Marcela Gomes; Santos, Danilo Henrique da Silva; Torres, Sheyla Jaqueline Albuquerque; Pimentel, Wagner Roberto Oliveira; Tonholo, Josealdo; Zanta, Carmem Lucia de Paiva E Silva

    2016-01-01

    This study aimed to determine the best method to treat a textile effluent containing the dye basic blue 99 (BB). Treatments by the electrochemical and the Fenton processes were compared by means of a 2(3) experimental design, and the interaction of experimental conditions for BB oxidation were determined. The electrochemical treatment gave better results in the presence of NaCl as electrolyte and high current density (30 mA cm(-2)); the Fenton reaction provided better results at H2O2 and Fe(2+) concentrations of 10 mg L(-1) and 0.5 mmol L(-1), respectively. Electrochemical treatment was 23 times faster than the Fenton reaction because formation of chlorinated species during electrooxidation significantly contributed to dye oxidation. Although the electrochemical process was more efficient, the resulting treated effluent was more toxic to Lactuca sativa germination and growth, which indicated some biotoxicity. Results demonstrated that both processes efficiently remediated effluents containing the dye BB, but they need to be combined with other processes to ensure complete adequacy of the effluent for disposal. PMID:27642834

  16. A more efficient approach to parallel-tempered Markov-chain Monte Carlo for the highly structured posteriors of gravitational-wave signals

    NASA Astrophysics Data System (ADS)

    Farr, Benjamin; Kalogera, Vicky; Luijten, Erik

    2014-07-01

    We introduce a new Markov-chain Monte Carlo (MCMC) approach designed for the efficient sampling of highly correlated and multimodal posteriors. Parallel tempering, though effective, is a costly technique for sampling such posteriors. Our approach minimizes the use of parallel tempering, only applying it for a short time to build a proposal distribution that is based upon estimation of the kernel density and tuned to the target posterior. This proposal makes subsequent use of parallel tempering unnecessary, allowing all chains to be cooled to sample the target distribution. Gains in efficiency are found to increase with increasing posterior complexity, ranging from tens of percent in the simplest cases to over a factor of 10 for the more complex cases. Our approach is particularly useful in the context of parameter estimation of gravitational-wave signals measured by ground-based detectors, which is currently done through Bayesian inference with MCMC, one of the leading sampling methods. Posteriors for these signals are typically multimodal with strong nonlinear correlations, making sampling difficult. As we enter the advanced-detector era, improved sensitivities and wider bandwidths will drastically increase the computational cost of analyses, demanding more efficient search algorithms to meet these challenges.

  17. Lignocellulosic ethanol: Technology design and its impact on process efficiency.

    PubMed

    Paulova, Leona; Patakova, Petra; Branska, Barbora; Rychtera, Mojmir; Melzoch, Karel

    2015-11-01

    This review provides current information on the production of ethanol from lignocellulosic biomass, with the main focus on relationships between process design and efficiency, expressed as ethanol concentration, yield and productivity. In spite of unquestionable advantages of lignocellulosic biomass as a feedstock for ethanol production (availability, price, non-competitiveness with food, waste material), many technological bottlenecks hinder its wide industrial application and competitiveness with 1st generation ethanol production. Among the main technological challenges are the recalcitrant structure of the material, and thus the need for extensive pretreatment (usually physico-chemical followed by enzymatic hydrolysis) to yield fermentable sugars, and a relatively low concentration of monosaccharides in the medium that hinder the achievement of ethanol concentrations comparable with those obtained using 1st generation feedstocks (e.g. corn or molasses). The presence of both pentose and hexose sugars in the fermentation broth, the price of cellulolytic enzymes, and the presence of toxic compounds that can inhibit cellulolytic enzymes and microbial producers of ethanol are major issues. In this review, different process configurations of the main technological steps (enzymatic hydrolysis, fermentation of hexose/and or pentose sugars) are discussed and their efficiencies are compared. The main features, benefits and drawbacks of simultaneous saccharification and fermentation (SSF), simultaneous saccharification and fermentation with delayed inoculation (dSSF), consolidated bioprocesses (CBP) combining production of cellulolytic enzymes, hydrolysis of biomass and fermentation into one step, together with an approach combining utilization of both pentose and hexose sugars are discussed and compared with separate hydrolysis and fermentation (SHF) processes. The impact of individual technological steps on final process efficiency is emphasized and the potential for use

  18. Efficient multi-objective calibration of a computationally intensive hydrologic model with parallel computing software in Python

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With enhanced data availability, distributed watershed models for large areas with high spatial and temporal resolution are increasingly used to understand water budgets and examine effects of human activities and climate change/variability on water resources. Developing parallel computing software...

  19. Investigation of the applicability of a functional programming model to fault-tolerant parallel processing for knowledge-based systems

    NASA Technical Reports Server (NTRS)

    Harper, Richard

    1989-01-01

    In a fault-tolerant parallel computer, a functional programming model can facilitate distributed checkpointing, error recovery, load balancing, and graceful degradation. Such a model has been implemented on the Draper Fault-Tolerant Parallel Processor (FTPP). When used in conjunction with the FTPP's fault detection and masking capabilities, this implementation results in a graceful degradation of system performance after faults. Three graceful degradation algorithms have been implemented and are presented. A user interface has been implemented which requires minimal cognitive overhead by the application programmer, masking such complexities as the system's redundancy, distributed nature, variable complement of processing resources, load balancing, fault occurrence and recovery. This user interface is described and its use demonstrated. The applicability of the functional programming style to the Activation Framework, a paradigm for intelligent systems, is then briefly described.

  20. Novel processes for high-efficiency biodigestion of particulate feeds

    SciTech Connect

    Ghosh, S.

    1984-01-01

    The development, application, and advantages of three advanced anaerobic digestion processes utilizing phase-separated fermentation and novel upflow digesters are described in this paper. The three processes described are (1) continuously stirred tank reactor (CSTR) two-phase digestion, (2) upflow two-phase digestion, and (3) leach-bed two-phase digestion. Unlike single-stage conventional digestion, these processes are suitable for the digestion of solid and concentrated semi-solid feeds, which are by far the largest biomass and waste resources available for simultaneous stabilization and energy production. All novel processes were significantly superior to conventional single-stage digestion in terms of methane yield and production rate, solids conversion efficiency, and net energy production. The upflow and the leach-bed two-phase digestion processes effected virtually complete conversion of the biodegradable fraction of the feed; the leach-bed process could accomplish this with a nutritionally deficient, highly cellulosic, refuse-derived substrate. 16 references, 5 figures, 5 tables.