One of the key factors for efficiency in distributedsimulation is the detection of model-inherent concurrency, which is related on the prediction of the future behavior of each logical simulation process. In this pap...
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One of the key factors for efficiency in distributedsimulation is the detection of model-inherent concurrency, which is related on the prediction of the future behavior of each logical simulation process. In this paper we present a generalization of traditional approaches to behavioral prediction which provides more accurate predictions in general and a high degree of scalability in terms of computational and communication overhead. We give a sequential implementation, prove its correctness using concepts from the analysis of real-time process networks and then show how these results can be used in distributedsimulation.
This paper describes Nops, a conservatively synchronized process-oriented parallelsimulation system. Nops is designed to support the programming model of the Telecommunications Description Language (TeD), with specia...
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This paper describes Nops, a conservatively synchronized process-oriented parallelsimulation system. Nops is designed to support the programming model of the Telecommunications Description Language (TeD), with special emphasis on scaling up to very large network models. We chronicle the decisions beyond Nops' design, describe that design, assess its raw performance relative to CSIM, Maisie, and GTW, and study its ability to scale to large models.
In this work we discuss the use and possible abuse of linear and inversive pseudorandom numbers (PRNs) in parallel and distributed environments. After an investigation of properties of PRNs which determine hour these ...
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ISBN:
(纸本)0818684577
In this work we discuss the use and possible abuse of linear and inversive pseudorandom numbers (PRNs) in parallel and distributed environments. After an investigation of properties of PRNs which determine hour these may be applied in such environments we introduce a software package which provides an unified and easy-to-use approach to the generating and handling of parallel streams of such PRNs. Experimental results are conducted which describe the features of the software package and compare the performance of two selected types of pseudorandom number *** this work we discuss the use and possible abuse of linear and inversive pseudorandom numbers (PRNs) in parallel and distributed environments. After an investigation of properties of PRNs which determine hour these may be applied in such environments we introduce a software package which provides an unified and easy-to-use approach to the generating and handling of parallel streams of such PRNs. Experimental results are conducted which describe the features of the software package and compare the performance of two selected types of pseudorandom number generators.
Data distribution management (DDM) is concerned with the problem of efficiently distributing state information among the entities in a distributedsimulation. While heavily studied in the DIS community for training ap...
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Data distribution management (DDM) is concerned with the problem of efficiently distributing state information among the entities in a distributedsimulation. While heavily studied in the DIS community for training applications using real-time synchronization, this problem has received considerably less attention for logical time simulations, and little performance data has appeared in this regard. This paper is concerned with evaluating the performance of a logical time synchronized.
A probabilistic scheduling policy for selecting the next event to be processed by a processor during optimistic parallel discrete event simulation is presented. This policy exploits the knowledge about statistical dis...
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A probabilistic scheduling policy for selecting the next event to be processed by a processor during optimistic parallel discrete event simulation is presented. This policy exploits the knowledge about statistical distributions of the difference between the timestamps of successively committed events of a logical process. simulation results are presented to demonstrate that under appropriate conditions probabilistic scheduling generates substantially fewer number of rollbacks compared to the lowest timestamp first scheduling policy.
A number of library-based parallel and sequential network simulators have been designed. This paper describes a library, called GloMoSim (for Global Mobile system Simulator), for parallelsimulation of wireless networ...
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ISBN:
(纸本)0818684577
A number of library-based parallel and sequential network simulators have been designed. This paper describes a library, called GloMoSim (for Global Mobile system Simulator), for parallelsimulation of wireless networks. GloMoSim has been designed to be extensible and composable: the communication protocol stack for wireless networks is divided into a set of layers, each with its own API. Models of protocols at one layer interact with those at a lower (or higher) layer only via these APIs. The modular implementation enables consistent comparison of multiple protocols at a given layer. The parallel implementation of GloMoSim can be executed using a variety of conservative synchronization protocols, which include the null message and conditional event algorithms This paper describes the GloMoSim library, addresses a number of issues relevant to its parallelization, and presents a set of experimental results on the IBM 9076 SP, a distributed memory multi-computer. These experiments use models constructed from the library modules.
The implementation of a cloning mechanism that allows for the evaluation of multiple simulated futures is presented and its performance is analyzed. A running parallel discrete event simulation is dynamically cloned a...
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ISBN:
(纸本)0818684577
The implementation of a cloning mechanism that allows for the evaluation of multiple simulated futures is presented and its performance is analyzed. A running parallel discrete event simulation is dynamically cloned at decision points to explore different execution paths concurrently. Ita this way what-if and alternative scenario analysis in gaming, tactical and strategic applications can be evaluated interactively or non-interactively. Performance results show that virtual logical processes, a new mechanism developed to avoid repeating common computations among clones improves efficiency.
With the emerging of broadband networks based on ATM technology, performance evaluation tools that allow the study of large systems are desperately needed. In this article we present our experiments in distributed sim...
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ISBN:
(纸本)0818684577
With the emerging of broadband networks based on ATM technology, performance evaluation tools that allow the study of large systems are desperately needed. In this article we present our experiments in distributedsimulation of large and complex ATM network models with a conservative simulator. The goal here was not to achieve the maximum speedup with well-shaped topologies but rather to see what speedup can be obtained with a realistic model on a "state-of-the art" parallel computer. A network model with 78 switches is simulated on a Gray T3E using 3 different traffic loads. The performance results show that good speedups can be achieved but also highlight partitioning problems and bottlenecks in the simulation model that can seriously limit the speedup of realistic model simulations.
This paper presents a sparse state saving scheme for Time Warp parallel discrete event simulation. The scheme bases the selection of the states to be recorded on the event history of the logical processes. To this pur...
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ISBN:
(纸本)0818684577
This paper presents a sparse state saving scheme for Time Warp parallel discrete event simulation. The scheme bases the selection of the states to be recorded on the event history of the logical processes. To this purpose, statistics on the virtual time advancement of the processes are collected for the prediction of virtual time intervals that are likely to contain rollback points;the states corresponding to the starting point of those intervals are recorded as checkpoints in order to reduce the average coasting forward. The percentage of states to be recorded is defined by a parameter whose value is dynamically recalculated on the basis of the on-line observation of the variation of a checkpointing-rollback cost function. simulation results of synthetic workloads are presented for a performance comparison with previous schemes.
One of the main reasons why parallel discrete event simulation has not been adopted more widely in industry is that the terminology used by the parallelsimulation community differs from that of industrial simulation ...
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One of the main reasons why parallel discrete event simulation has not been adopted more widely in industry is that the terminology used by the parallelsimulation community differs from that of industrial simulation practitioners. This paper shows how the gap between these two communities can be bridged by presenting a methodology for automating the parallelization of manufacturing simulations. Our approach provides a way of automatically generating a mapping from a sequential simulation model to an efficient parallel implementation. The results of this mapping can be expressed in a form which is independent of any particular parallelsimulation system or language. Since it is easy to generate code for different simulation systems, it is possible to evaluate alternative parallelsimulation protocols at an early stage of development. A prediction of the performance can thus be obtained by studying the behaviour of an abstraction of the simulation model with various strategies or on different computing platforms.
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