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International Symposium on Parallel and Distributed Processing (IPDPS)

作者： Kai Wang Sangbae Kim Jun Zhang K. Nakajima H. Okuda Laboratory for High Performance Scientific Computing and Computer Simulation Department of Computer Science University of Kentucky Lexington KY USA Research Organization for Information Science and Technology Meguro Tokyo Japan Department of Quantum Engineering and System Sciences University of Tokyo Bunkyo Tokyo Japan

We investigate and compare a few parallel preconditioning techniques in the iterative solution of large sparse linear systems arising from solid Earth simulation with and without using contact information in the domain partitioning process. Previous studies are focused on using static or matrix pattern based incomplete LU (ILU) preconditioners in a localized preconditioner implementation. Our current studies are concerned with preconditioner performance for solving two different cases with and without known contact information. For the cases with contact information, we use localized threshold value based incomplete LU (ILUT) preconditioner to improve efficiency. For the cases without contact information, we use a global sparse approximate inverse preconditioner with a static sparsity pattern to achieve robustness. Numerical results from simulating ground motion on a parallel supercomputer are given to compare the effectiveness of these parallel preconditioning techniques.

关键词： Large-scale systems Earth Solid modeling Linear systems Sparse matrices Computational modeling computer simulation Uniform resource locators Geoscience Information science

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Scheduling algorithms with bus bandwidth considerations for SMPs

Scheduling algorithms with bus bandwidth considerations for ...

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International Conference on Parallel Processing (ICPP)

作者： C.D. Antonopoulos D.S. Nikolopoulos T.S. Papatheodorou High Performance Information Systems Laboratory Computer Engineering & Informatics Department University of Patras Patras Greece Department of Computer Science The College of William and Mary Williamsburg VA USA

The bus that connects processors to memory is known to be a major architectural bottleneck in SMPs. However, both software and scheduling policies for these systems generally focus on memory hierarchy optimizations and do not address the bus bandwidth limitations directly. We first present experimental results which indicate that bus saturation can cause an up to almost three-fold slowdown to applications. Motivated by these results, we introduce two scheduling policies that take into account the bus bandwidth consumption of applications. The necessary information is provided by performance monitoring counters which are present in all modern processors. Our algorithms organize jobs so that processes with high-bandwidth and low-bandwidth demands are co-scheduled to improve bus bandwidth utilization without saturating the bus. We found that our scheduler is effective with applications of varying bandwidth requirements, from very low to close to the limit of saturation. We also tuned our scheduler for robustness in the presence of bursts of high bus bandwidth consumption from individual jobs. The new scheduling policies improve system throughput by up to 68% (26% in average) in comparison with the standard Linux scheduler

关键词： Scheduling algorithm Bandwidth Switched-mode power supply Processor scheduling Yarn Educational institutions Interference Information systems high performance computing Systems engineering and theory

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Self-adapting, self-optimizing runtime management of Grid applications using PRAGMA

Self-adapting, self-optimizing runtime management of Grid ap...

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International Symposium on Parallel and Distributed Processing (IPDPS)

作者： H. Zhu M. Parashar J. Yang Y. Zhang S. Rao S. Hariri The Applied Software System Laboratory Department of Electrical and Computer Engineering Rutgers State University of New Jersey Piscataway NJ USA High Performance Distributed Computing Department of Electrical and Computer Engineering University of Arizona Tucson Tucson AZ USA

The emergence of the computational Grid and the potential for seamless aggregation, integration and interactions has made it possible to conceive a new generation of realistic, scientific and engineering simulations of complex physical phenomena. The inherently heterogeneous and dynamic nature of these application and the Grid presents significant runtime management challenges. In this paper we extend the PRAGMA framework to enable self adapting, self optimizing runtime management of dynamically adaptive applications. Specifically, we present the design, prototype implementation and initial evaluation of policies and mechanisms that enable PRAGMA to autonomically manage, adapt and optimize structured adaptive mesh refinement applications (SAMR) based on current system and application state and predictive models for system behavior and application performance. We use the 3-D adaptive Richtmyer-Meshkov compressible fluid dynamics application and Beowulf clusters at Rutgers University, University of Arizona, and NERSC to develop our performance models, and define and evaluate our adaptation policies. In our prototype, the predictive performance models capture computational and communicational loads and, along with current system state, adjust processors capacities at runtime to enable the application to adapt and optimize its performance.

关键词： Runtime Disaster management Computational modeling Prototypes Predictive models Grid computing Physics computing Mesh generation Design engineering Design optimization

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MedIGrid: a medical imaging application for computational Grids

MedIGrid: a medical imaging application for computational Gr...

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International Symposium on Parallel and Distributed Processing (IPDPS)

作者： M. Bertero P. Bonetto L. Carracciuolo L. D'Amore A. Formiconi M.R. Guarracino G. Laccetti A. Murli G. Oliva Department of Computer and Information Science University of Genoa Italy Institute for High Performance Computing and Networking CNR Naples Italy Department of Mathematics and Applications University of Napoli Federico II Italy Department of Clinical Phisiopatology University of Florence Italy

In the last decades, diagnosing medical images has heavily relied on digital imaging. As a consequence, huge amounts of data produced by modern medical instruments need to be processed, organized, and visualized in a suitable response time. Many efforts have been devoted to the development of digital Picture Archiving and Communications Systems (PACS) which archive and distribute image information across a hospital and provide Web access to avoid the expensive deployment of a large number of such systems. On the other hand, this approach does not solve problems related to the increasing demand of high performance computing and storage facilities, which cannot be placed within a hospital. In this work we describe MedIGrid, an application that enables nuclear doctors to transparently use high performance computers and storage systems for the PET/SPECT (Positron Emission Tomography/Single Photon Emission Computed Tomography) image processing, management, visualization and analysis. MedIGrid is the result of the joint efforts of a group of researchers committed to the development of a distributed application to test and deploy new reconstruction methods in clinical environments. The outcomes of this work include a set of platform independent software tools to read medical images, control the execution of computing intensive tomographic algorithms, and explore the reconstructed tomographic volumes. In the paper we describe how the collaboration among different research groups has contributed to the integration of the application into a single framework. The results of our work are discussed.

关键词： Biomedical imaging computer applications Grid computing Medical diagnostic imaging Application software Picture archiving and communication systems Hospitals high performance computing Image storage Positron emission tomography

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Real-time embedded system support for the BTeV level 1 muon trigger

Real-time embedded system support for the BTeV level 1 muon ...

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2003 IEEE Nuclear science Symposium Conference Record - Nuclear science Symposium, Medical Imaging Conference

作者： Haney, Michael J. Beauregard, D. Iyer, R. Kalbarczyk, Z. Liu, Q. Wang, L. Haney, M. Selen, M. Mosse, D. Shigiltchoff, O. Chopade, R. Hovey, L. Jung, M. Messie, D. Oh, J. Stone, S. Bapty, T. Neema, S. Nordstrom, S. Shetty, S. Vashishtha, S. Yao, D. Sheldon, P. Vaandering, E. Butler, J. Gottschalk, E. Kowalkowski, J. Votava, M. Appel, J. University of Illinois Urbana IL 61801 United States Des./Validation Reliable N.S.R.G. University of Illinois High Energy Physics Group Department of Physics University of Illinois Department of Computer Science Coll. in High Sch. Educ. Program University of Pittsburgh Department of Electrical Engineering Syracuse University High Energy Physics Group Department of Physics Syracuse University Inst. for Software Intgd. Systems Vanderbilt University Department of Physics BTeV Group Vanderbilt University BTeV Collaboration Particle Physics Division Fermi Natl. Accelerator Laboratory Computing Division Fermi Natl. Accelerator Laboratory Fermilab Education Office Fermi Natl. Accelerator Laboratory

The Level 1 Muon Trigger subsystem for BTeV will be implemented using the same architectural building blocks as the BTeV Level 1 Pixel Trigger: pipelined field programmable gate arrays feeding a farm of dedicated processing elements. The muon trigger algorithm identifies candidate tracks, and is sensitive to the muon charge (sign);candidate dimuon events are identified by complementary charge track-pairs. To insure that the trigger is operating effectively, the trigger development team is actively collaborating in an independent multi-university research program for reliable, self-aware, fault adaptive behavior in real-time embedded systems (RTES). Key elements of the architecture, algorithm, performance, and engineered reliability are presented.

关键词： Embedded systems

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Integrating MPI-based numerical software into an advanced parallel computing environment

Integrating MPI-based numerical software into an advanced pa...

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Euromicro Conference on Parallel, Distributed and Network-Based Processing

作者： P. D'Ambra M. Danelutto D. di Serafino M. Lapegna Institute for High-Performance Computing and Networking (ICAR) National Research Council Naples Italy Department of Computer Science University of Pisa Pisa Italy Department of Mathematics Second University of Naples Caserta Italy Department of Mathematics and its Applications University of Naples Federico II Naples Italy

In this paper we present first experiences concerning the integration of MPI-based numerical software into an advanced programming environment for building parallel and distributed high-performance applications, which is under development in the context of Italian national research projects. Such a programming environment, named ASSIST, is based on a combination of the concepts of structured parallel programming and component-based programming. Some activities within the projects are devoted to the definition, implementation and testing of a methodology for the integration of a parallel numerical library into ASSIST. The goal is providing a set of efficient, accurate and reliable tools that can be easily used as building blocks for high-performance scientific applications. We focus on the integration of existing and widely used MPI-based numerical library modules. To this aim, we propose a general approach to embed MPI computations into the ASSIST basic programming unit. This approach has been tested using the MPICH implementation of MPI for networks of workstations. Some modifications have been applied to the MPICH process startup procedure, in order to make it compliant with the ASSIST environment. Results of experiments concerning the integration of routines from a well-known FFT package are discussed.

关键词： Parallel processing Programming environments Parallel programming Testing Libraries Buildings Application software Embedded computing Workstations Packaging

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An improved genetic algorithm with variable population-size and a PSO-GA based hybrid evolutionary algorithm

An improved genetic algorithm with variable population-size ...

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International Conference on Machine Learning and Cybernetics (ICMLC)

作者： X.H. Shi L.M. Wan H.P. Lee X.W. Yang L.M. Wang Y.C. Liang College of Computer Science and Technology Jilin University Changchun China The 8th Research Institute of Air Force Beijing China Institute of High Performance Computing Singapore Singapore Department of Applied Mathematics South China University of Technology Guangzhou China

This paper presents an improved genetic algorithm with variable population-size (VPGA) inspired by the natural features of the variable size of the population. Based on the VPGA and the particle swarm optimization (PSO) algorithms, this paper also proposes a novel hybrid approach called PSO-GA based hybrid evolutionary algorithm (PGBHEA). Simulations show that both VPGA and PGBHEA are effective for the optimization problem.

关键词： Genetic algorithms Evolutionary computation Particle swarm optimization Computational modeling Biological cells Educational institutions computer science high performance computing Mathematics Data structures

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A synthetic computational-intelligence-based method and its application in identifying water-flooded zones in oil field

A synthetic computational-intelligence-based method and its ...

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International Conference on Machine Learning and Cybernetics (ICMLC)

作者： X.H. Shi S.M. Wang X.G. Sui Y.C. Gao H.P. Lee Y.C. Liang College of Computer Science and Technology Jilin University Changchun China First Oil Production Factory Daqing Oilfield Corporation Limited Daqing China Department of Elementary Education Daqing Advanced College Daqing China Institute of High Performance Computing Singapore Singapore

Inspired by the natural features of the variable size of the population, an improved genetic algorithm with variable population-size (VPGA) is presented in this paper. Based on the VPGA, a novel synthetic computational-intelligence-based method (SCIBM) is proposed and applied to the identification of water-flooded zones in the oil field. This method integrates evolutionary neural networks and recognition technique for multi-point-data neural networks. Simulation results applying the SCIBM to actual logging data in Daqing Oil Field show that the proposed method works well in the identification of water-flooded zones.

关键词： Petroleum Biological cells Genetic algorithms Neural networks Computational modeling Application software Educational institutions Biological system modeling Evolution (biology) computer networks

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A neural-network-based iterative controller of speed control for ultrasonic motors

A neural-network-based iterative controller of speed control...

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International Conference on Machine Learning and Cybernetics (ICMLC)

作者： X.H. Shi L. Shi L.M. Wan X.W. Yang X. Xu Y.C. Liang College of Computer Science and Technology Jilin University Changchun China The 8th Research Institute of Air Force Beijing China Department of Applied Mathematics South China University of Technology Guangzhou China College of Mathematics Jilin University Changchun China Institute of High Performance Computing Singapore

A neural-network-based iterative controller is presented focusing on the speed control of ultrasonic motors. Suitable ranges of the adaptive learning rates are presented through the theoretical analysis on the proposed model, which could guarantee the fastest convergence of the neural network controller. Numerical results show that the neural-network-based controller is effective for various kinds of reference speeds of ultrasonic motors. Comparisons with the existing method show that the precision of control could be increased using the proposed method. Simulations also show that the proposed scheme is fairly robust against random disturbance to the control variables.

关键词： Velocity control Neural networks Control systems Error correction Wide area networks Educational institutions computer science Mathematics high performance computing Force control

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Optimal Bandwidth Utilization of All—Optical Ring with a Converter of Degree 4

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Journal of computer science & Technology 2002年第4期17卷 411-419页

作者：许胤龙陈国良黄刘生万颖瑜 Department of Computer Science and Technology University of Science and Technology of China National High Performance Computing Center at Hefei Hefei 230027 P.R. China

In many models of all-optical routing, a set of communication paths in a network is given, and a wavelength is to be assigned to each path so that paths sharing an edge receive different wavelengths. The goal is to assign as few wavelengths as possible, in order to use the optical bandwidth efficiently. If a node of a network contains a wavelength converter,any path that passes through this node may change its wavelength. Having converters at some of the nodes can reduce the number of wavelengths required for routing. This paper presents a wavelength converter with degree 4 and gives a routing algorithm which shows that any routing with load L can be realized with L wavelengths when a node of an all-optical ring hosts such a wavelength converter. It is also proved that 4 is the minimum degree of the converter to reach the full utilization of the available wavelengths if only one node of an all-optical ring hosts a converter.

关键词： all-optical network ring wavelength assignment wavelength translation

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