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1999 International workshop on Innovative Architectures, IWIA 1999

作者： Velamparambil, Sanjay Song, Jiming Chew, Weng Cho Dept. of Electrical and Computer Engg. Center for Computational Electromagnetics University of Illinois UrbanaIL61801 United States

ISBN: (纸本)076950650X

In recent years, the Multilevel Fast Multipole Method (MLFMA) [14, 17} has been developed into one of the most powerful techniques for accelerating the iterative solution of integral equations of electromagnetics. It has been shown that the MLFMA reduces the computational complexity of a matrix-vector multiply from 0(N2) to 0{N log A'), where N is the number of unknowns. In an attempt to extend the range of problems that can be solved using this technique, we have recently developed an application independent, parallel MLFMA kernel, called ScaleME. for distributed memory computers using MP1. In this paper, we shall discuss the characteristic features which distinguishes it from its static counterpart, such as work required for each level, the size of multipole expansions and interpolation/filtering operations, and their influence in the parallel algorithm design. We shall follow it with a discussion of major issues in the paralleliza-Tion which are unique to the dynamic MLFMA, such as reducing the memory requirements for translation operators and the reduction of replicated geometric data structures. We shall also briefly discuss the load balancing strategies. Finally, we shall present some representative numerical results from some ScalaME accelerated electromagnetic scattering codes, including a simulation involving 4 million unknowns and that of the radar cross-section computation of a full scale air-craft on a Beowulf class cluster. © 2000 IEEE.

关键词： Integral equations

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Design of highly parallel edge detection nodes using evolutionary techniques

Design of highly parallel edge detection nodes using evoluti...

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Euromicro workshop on parallel and distributed Processing

作者： G.S. Hollingworth S.L. Smith A.M. Tyrrell Department of Electronics University of York UK

This paper considers the application of bio-inspired systems in the design of a novel and highly parallel image processing tool to detect edges within conventional grey-scale images. The aim of the work is to implement a new image processing architecture through evolvable hardware that is able to adapt according to the particular images encountered. The simulation of such a system through the use of evolutionary algorithms and genetic programming is demonstrated for the conventional image processing operation of edge detection. Results are presented for this system and evaluated with respect to a conventional Sobel edge detector.

关键词： Image edge detection DNA Image processing Evolutionary computation Genetic programming Phylogeny Design engineering Councils Detectors Computer science

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An auto-adaptive dead reckoning algorithm for distributed interactive simulation

An auto-adaptive dead reckoning algorithm for distributed in...

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workshop on Principles of Advanced and distributed simulation (PADS)

作者： Wentong Cai F.B.S. Lee L. Chen School of Applied Science Nanyang Technological University Singapore

This paper describes a new, auto-adaptive algorithm for dead reckoning in DIS. In general dead-reckoning algorithms use a fixed threshold to control the extrapolation errors. Since a fixed threshold cannot adequately handle the dynamic relationships between moving entities, a multi-level threshold scheme is proposed. The definition of threshold levels is based on the concepts of area of interest (AOI) and sensitive region (SR), and the levels of threshold are adaptively adjusted based on the relative distance between entities during the simulation. Various experiments were conducted. The results show that the proposed auto-adaptive dead reckoning algorithm can achieve considerable reduction in update packets without sacrificing accuracy in extrapolation.

关键词： Dead reckoning Extrapolation Error correction Standards development Equations Adaptive filters Filtering Adaptive algorithm Joining processes Large-scale systems

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Efficient optimistic parallel simulations using reverse computation

Efficient optimistic parallel simulations using reverse comp...

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workshop on Principles of Advanced and distributed simulation (PADS)

作者： C.D. Carothers K.S. Perumalla R.M. Fujimoto Department of Computer Science Rensselaer Polytechnic Institute Troy NY USA College of Computing Georgia Institute of Technology Atlanta GA USA

In optimistic parallel simulations, state-saving techniques have been traditionally used to realize rollback. We propose reverse computation as an alternative approach, and compare its execution performance against that of state-saving. Using compiler techniques, we describe an approach to automatically generate reversible computations, and to optimize them to transparently reap the performance benefits of reverse computation. For certain fine-grain models, such as queuing network models, we show that reverse computation can yield significant improvement in execution speed coupled with significant reduction in memory utilization, as compared to traditional state-saving. On sample models using reverse computation, we observe as much as three-fold improvement in execution speed over traditional state-saving.

关键词： Computational modeling Concurrent computing Computer science Educational institutions Optimizing compilers Computer networks Discrete event simulation Loss measurement Delay

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Active Virtual Network Management Protocol

Active Virtual Network Management Protocol

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workshop on Principles of Advanced and distributed simulation (PADS)

作者： S.F. Bush General Electric Corporate Research and Development Center Niskayuna NY USA

This paper introduces a novel algorithm, the Active Virtual Network Management Protocol (AVNMP), for predictive network management. It explains how the Active Virtual Network Management Protocol facilitates the management of an active network by allowing future predicted state information within an active network to be available to network management algorithms. This is accomplished by coupling ideas from optimistic discrete event simulation with active networking. The optimistic discrete event simulation method used is a form of self-adjusting Time Warp. It is self-adjusting because the system adjusts for predictions which are inaccurate beyond a given tolerance. The concept of a streptichron and autoanaplasis are introduced as mechanisms which take advantage of the enhanced flexibility and intelligence of active packets. Finally, it is demonstrated that the Active Virtual Network Management Protocol is a feasible concept.

关键词： Protocols Communication networks Communication system security Information security Research and development management Discrete event simulation Information management Computer networks Computer network management Quality management

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Beyond speedup: PADS, the HLA and Web-based simulation 99

Beyond speedup: PADS, the HLA and Web-based simulation

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proceedings of the thirteenth workshop on parallel and distributed simulation

作者： Ernest H. Page The MITRE Corporation 1820 Dolley Madison Boulevard McLean VA

This year's installment of the PADS "community assessment" looks at previous assessments and considers some current directions in distributed simulation and their possible relationship to PADS.

ISBN: (纸本)9780769501550

This year's installment of the PADS "community assessment" looks at previous assessments and considers some current directions in distributed simulation and their possible relationship to PADS.

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Fast-software-checkpointing in optimistic simulation: embedding state saving into the event routine instructions

Proceedings of the Workshop on Parallel and Distributed Simu...

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proceedings of the workshop on parallel and distributed simulation, PADS 1999年 118-125页

作者： Quaglia, Francesco Universita' di Roma 'La Sapienza' Roma Italy

In this paper we present a software approach, namely Fast-Software-Checkpointing (FSC), to reduce the running time of the state saving protocol in optimistic parallel discrete event simulation. The idea behind FSC is to use the instructions performed during the execution of an event as part of the state saving protocol, hence the total number of instructions due to state saving is reduced. Under FSC the time for saving the state of a logical process prior to the execution of an event e requires an amount of time proportional to be amount of state variables not updated by e's execution, as only these variables must be copied. This outlines that FSC shows some dualism with respect to incremental state saving. We show, however, that there exists a basic difference between the two solutions as in FSC some of the state saving instructions are actually event routine instructions, while in incremental state saving they are only added and mixed to the latter ones. We also present a simple software architecture to support FSC and simulation results to demonstrate the effectiveness of such solution. The obtained data show that FSC, combined with a sparse state saving strategy, may represent the best checkpointing solution in case of both medium/small state granularity simulations and large state granularity simulations even with small (but non-minimal) portions of the state updated by event execution. FSC may result therefore suited for a wide class of simulation problems.

关键词： Computer simulation

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Experience in retrofitting a large sequential Ada simulator to two versions of time warp

Proceedings of the Workshop on Parallel and Distributed Simu...

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proceedings of the workshop on parallel and distributed simulation, PADS 1999年 74-81页

作者： Smith, Ray Andress, Randal Parsons, George M. TRW Systems & Information Technology Group

The Extended Air Defense Testbed (EADTB), is a comprehensive, high- and mixed-level-of-detail, environment for modeling weapon system entities and interactions. Due to the complexity of the models and large scenario sizes, in its current single-threaded form, EADTB is limited in run-time speed. Our goal is to speed up the simulation without re-architecture or re-implementation of the models which comprise 1.76 million lines of Ada code, and without altering model behavior or compromising repeatability and causality. Our work demonstrates that the use of 'optimistic scheduling' techniques and its derivatives, offers the best alternative for object-based systems like EADTB. Specifically we have retrofitted and integrated the same representative pseudo-EADTB prototype with two different object-oriented optimistic scheduling engines (SPEEDES and TEMPO/Thema). We discuss the required architectural and behavioral features of a simulation to allow this retrofit, the issues of C++ to Ada language interfaces, and the employment of the basic services of the optimistic scheduling engines in this environment. Experimental results suggest that order-of-magnitude speed-up is feasible through parallelization, and is scalable to larger experiments simply by adding hardware.

关键词： Computer simulation languages

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Performance of dynamic load balanced join algorithms in shared disk parallel database systems

Performance of dynamic load balanced join algorithms in shar...

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IEEE workshop on Future Trends of distributed Computing Systems

作者： Aekyung Moon Kyungho On Haengrae Cho Department of Computer Engineering Yeungnam University Kyongbuk South Korea

ISBN: (纸本)076950468X

parallel database systems are the key to high performance database processing. In this paper, we propose parallel join algorithms in shared disk parallel database systems, where all coupled nodes are connected via a high-speed network and share a common database at the disk level. The proposed algorithms are novel in the sense that they can provide a higher potential for dynamic load balancing with the inherent flexibility of the shared disk architecture. Using a parallel database simulation model, we evaluate the performance of the proposed algorithms under a wide variety of system configurations and database workloads.

关键词： Database systems Partitioning algorithms Tin Query processing High-speed networks Load management Moon Concurrent computing Data engineering Transaction databases

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Specification and simulation of a concurrent real-time system

International Workshop on Software Engineering for Parallel ...

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International workshop on Software Engineering for parallel and distributed Systems, proceedings 1999年 197-204页

作者： Li, Xiaoshan Univ of Macau Macau China

Interval Temporal Logic (ITL) is real-time logic for specifying and verifying real-time systems. In this paper, ITL is used to specify a concurrent real-time system: assembly line which is an abstract model of industrial robot control systems. We can specify the abstract properties of the system in ITL as well as the system design using the executable subset of ITL, Tempura. Comparing with other approaches, the first advantage of this methodology is that the concurrent real-time systems can be naturally specified in true concurrent model rather than interleaving model. The second is that the specification of system design is executable so that the simulation can be obtained in the same formal framework. Therefore, both the properties of the system and the consistency of specification can be checked before verification.

关键词： Real time systems

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