In the area of telerobotics, where remote systems are to be controlled, it is helpful to plan subsequent operations based on as much relevant data as possible. The simulation of the remote system, executed in parallel...
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In the area of telerobotics, where remote systems are to be controlled, it is helpful to plan subsequent operations based on as much relevant data as possible. The simulation of the remote system, executed in parallel, can provide additional information, otherwise difficult or impossible to retrieve from sensor feedback. In this paper, the integrated DiSCUS environment (distributedsimulation and Control in a Unix System) is presented, which is used for the simulation and the control of a small assembly cell. All (physical and logical) components are represented as stand-alone programs, as tasks. These tasks are distributed over a workstation network, so that "true" parallelism can be achieved.< >
We present analytic models and simulation techniques that describe the performance of the multifrontal method on distributed memory architectures. We focus on particular strategies for partitioning, clustering, and ma...
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We present analytic models and simulation techniques that describe the performance of the multifrontal method on distributed memory architectures. We focus on particular strategies for partitioning, clustering, and mapping of task nodes to processors in order to minimize the overall parallel execution time and minimize communication costs. The performance model has bees used to obtain estimates for the speedups of various engineering and scientific problems, on several distributed architectures. The result is that the available parallelism of these problems is strongly dependent on the sparsity structure of the input matrices.< >
Responsive systems are fault-tolerant, real-time systems in parallel and distributed environments. Recently, several approaches to responsive system design have been developed. By incorporating key concepts in these a...
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Responsive systems are fault-tolerant, real-time systems in parallel and distributed environments. Recently, several approaches to responsive system design have been developed. By incorporating key concepts in these approaches to communication protocols, responsive protocols are defined as protocols that can revert to a normal state in bounded time, even when they enter abnormal states due to faults. Fundamentally, communication protocols can be made responsive by adding timely checkpointing and rollback recovery to them. In this paper, we discuss fault-tolerant, real-time performance (called responsiveness) of such protocols and propose an algorithm to compute responsiveness of protocols whose reachability graphs form acyclic directed graphs. Finally, we also present several simulation results to analyze dynamic behaviors of such protocols.
The proceedings contain 24 papers. The special focus in this conference is on Evolutionary Computing. The topics include: Formal memetic algorithms;a statistical mechanical formulation of the dynamics of genetic algor...
ISBN:
(纸本)9783540584834
The proceedings contain 24 papers. The special focus in this conference is on Evolutionary Computing. The topics include: Formal memetic algorithms;a statistical mechanical formulation of the dynamics of genetic algorithms;evolutionary stability in simple classifier systems;nonbinary transforms for genetic algorithm problems;enhancing evolutionary computation using analogues of biological mechanisms;exploiting mate choice in evolutionary computation;an empirical comparison of selection methods in evolutionary algorithms;genetic algorithms and directed adaptation;genetic algorithms and neighbourhood search;a unified paradigm for parallel genetic algorithms;distributed coevolutionary genetic algorithms for multi-criteria and multi-constraint optimisation;inductive operators and rule repair in a hybrid genetic learning system;adaptive learning of a robot arm;co-evolving co-operative populations of rules in learning control systems;learning anticipatory behaviour using a delayed action classifier system;applying a restricted mating policy to determine state space niches using immediate and delayed reinforcement;a comparison between two architectures for searching and learning in maze problems;fast practical evolutionary timetabling;optimising a presentation timetable using evolutionary algorithms;genetic algorithms for digital signal processing;complexity reduction using expansive coding and the application of genetic programming to the investigation of short, noisy, chaotic data series.
This paper presents a new fast way to simulate large networks of computers. The method uses a frontend EC, which accepts a parallel C program and translates it into a program in an intermediate language for parallel s...
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This paper presents a new fast way to simulate large networks of computers. The method uses a frontend EC, which accepts a parallel C program and translates it into a program in an intermediate language for parallel system simulations. An event driven simulator for distributed shared memory systems, DSIM, uses the intermediate language to simulate and obtain efficiency results in networks of thousands of processors. In simulations of large parallel systems, enormous memory needs and long execution times are major difficulties. To minimize these problems, the new method analyzes system performance by using extracted execution step information, e.g. the number of shored writes in a code segment, to predict task completion times rather than executing the program step by step. Workstation evaluations of parallel codes running on several thousand processors are feasible using EC/DSIM.< >
We obtain stochastic bounds on execution times of parallel computations assuming ideal conditions for shared resources. A parallel computation is modelled as a task system with precedence constraints expressed as a di...
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We obtain stochastic bounds on execution times of parallel computations assuming ideal conditions for shared resources. A parallel computation is modelled as a task system with precedence constraints expressed as a directed acyclic graph (DAG). The task execution times are assumed independent random variables. The performance measure considered is the overall execution time of the computation. To obtain upper bounds on this measure, we apply stochastic ordering and stochastic comparison techniques.< >
IVD, Interactive Visualization Debugger is intended to provide on-line and integrated mechanisms for debugging, performance analysis, and data visualization for message-passing parallel applications. The current IVD i...
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IVD, Interactive Visualization Debugger is intended to provide on-line and integrated mechanisms for debugging, performance analysis, and data visualization for message-passing parallel applications. The current IVD includes: (I) ESP, a mechanism to multicast window-based commands from a single control window to some subset of existing debuggers/visualizers on various processes; (2) program replay to reproduce program runs deterministically to enable cyclic debugging; and (3) ad hoc data visualization of distributed arrays using existing visualizers.< >
In this paper, we consider the problem of partitioning a conservative parallelsimulation for execution on a multi-computer. The synchronization protocol makes use of null messages [6]. We propose the use of a simulat...
ISBN:
(纸本)9781565550278
In this paper, we consider the problem of partitioning a conservative parallelsimulation for execution on a multi-computer. The synchronization protocol makes use of null messages [6]. We propose the use of a simulated annealing algorithm with an adaptive search schedule to find good (sub-optimal) partitions. The paper discusses the algorithm, its implementation and reports on the performance results of simulations of a partitioned FCFS queueing network model executed on iPSC/860 hypercube. The results obtained are compared with a random partitioning. They show that a partitioning which makes use of our simulated annealing algorithm results in a reduction of 25-35% of the running time of the simulations when compared to the running time of a random partition of the model.
Large concurrent or distributed systems have proven notoriously difficult to comprehend due to their combinatoric complexity. There is a clear need for thorough formal system modeling at all design stages. Ease of use...
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Large concurrent or distributed systems have proven notoriously difficult to comprehend due to their combinatoric complexity. There is a clear need for thorough formal system modeling at all design stages. Ease of use and validation capability are important criteria in method selection. It is important that the selection permit evaluation of design details with respect to performance and behavioral goals. Net models are a likely candidate to achieve the requisite needs of such a modeling environment. They provide both graphical and mathematical system modeling views which inherently enable both quantitative and qualitative analysis of the design. To demonstrate this claim, a colored Petri Net model and performance analysis of a particular scalable multiprocessor interconnect fabric is presented. The fundamental component of this fabric is an adaptive routing device, R2. The R2 fabric is based on the interconnection scheme used in the Mayfly parallel processing system.< >
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