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Proceedings of the sixteenth workshop on parallel and distributed simulation

作者： Jason Liu David M. Nicol Dartmouth College Hanover NH

ISBN: (纸本)9780769516080

Rapid growth in wireless communication systems motivates the development of technology supporting the simulation of large-scale wireless systems. However, it is widely recognized that wireless communications do not have substantial "lookahead" needed by conservative synchronization protocols. This paper focuses on identifying and exploiting lookahead for such models. We find lookahead in three ways, exploiting characteristics of low power networks, the transceiver logic, and the way in which protocol stacks are typically constructed. We show how these observations allow a variety of conservative synchronization protocols to take advantage of lookahead, describe a synchronization method we use, and empirically examine the performance this method offers on a large-scale simulation of a sensor network intended for homeland defense scenarios

关键词： performance conservative parallelsimulation synchronization sensor networks. parallel simulation parallel discrete-event simulation wireless networks ad hoc networks lookahead

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A cost model for selecting checkpoint positions in time warp parallel simulation

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IEEE TRANSACTIONS ON parallel AND DISTRIBUTED SYSTEMS 2001年第4期12卷 346-362页

作者： Quaglia, F Univ Roma La Sapienza Dipartimento Informat & Sistemist I-00198 Rome Italy

Recent papers have shown that the performance of Time Warp simulators can be improved by appropriately selecting the positions of checkpoints, instead of taking them on a periodic basis. In this paper, we present a checkpointing technique in which the selection of the positions of checkpoints is based on a checkpointing-recovery cost model. Given the current state S, the model determines the convenience of recording S as a checkpoint before the next event is executed. This is done by taking into account the position of the last taken checkpoint, the granularity (i.e., the execution time) of intermediate events, and using an estimate of the probability that S will have to be restored due to rollback in the future of the execution. A synthetic benchmark in different configurations is used for evaluating and comparing this approach to classical periodic techniques. As a testing environment we used a cluster of PCs connected through a Myrinet switch coupled with a fast communication layer specifically designed to exploit the potential of this type of switch. The obtained results point out that our solution allows faster execution and, in some cases, exhibits the additional advantage that less memory is required for recording state vectors. This possibly contributes to further performance improvements when memory is a critical resource for the specific application. A performance study for the case of a cellular phone system simulation is finally reported to demonstrate the effectiveness of this solution for a real world application.

关键词： parallel discrete-event simulation checkpointing rollback-recovery time warp optimistic synchronization performance optimization cost models

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A geographically distributed enterprise simulation system

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FUTURE GENERATION COMPUTER SYSTEMS-THE INTERNATIONAL JOURNAL OF ESCIENCE 2000年第2期17卷 135-146页

作者： Ammerlahn, HR Goldsby, ME Johnson, MM Nicol, DM Sandia Natl Labs Syst Studies Dept 8114 Livermore CA 94551 USA Dartmouth Coll Hanover NH 03755 USA

Sandia National Laboratories has the role of system integrator in the US Department of Energy's Nuclear Weapons Complex (NWC) and the responsibility for maintaining the nuclear stockpile. Maintenance is a complex task that involves a great number of geographically distributed functions, and a variety of analysis tools and models are used to plan operations, assess capabilities and guide political decisions. We are developing a framework for modeling the NWC unde interactive human control. The framework consists of a simulation system whose users and components are distributed across the entire United States. The purpose of the system is to support decisions about questions ranging from low-level operational matters involving only a sub-component of the complex to high-level policy issues requiring simulation of the entire complex. The system integrates multiple domain-specific legacy models and policy models and allows simulation at varying levels of detail. To provide such a framework, we have had to address a number of technical problems, whose solution is the focus of this paper. The three most fundamental problems are to provide geographically distributed, synchronized human participation in the simulation;to provide distributed ownership and security in such a way that the facility hosting a domain-specific model retains all rights to provide or deny a user access to its information;and to integrate legacy models written in a variety of tools or languages and executed on different platforms. Key features of our approach are the use of the Java language and the coordination of the simulation through a new parallel discrete-event simulation system. (C) 2000 Elsevier Science B.V. All rights reserved.

关键词： enterprise modeling parallel discrete-event simulation human-in-the-loop distributed role-based access control Java security legacy systems

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Visualizing parallel simulations that execute in network computing environments

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FUTURE GENERATION COMPUTER SYSTEMS-THE INTERNATIONAL JOURNAL OF GRID COMPUTING AND ESCIENCE 1999年第4期15卷 513-529页

作者： Carothers, CD Topol, B Fujimoto, RM Stasko, JT Sunderam, V Rensselaer Polytech Inst Dept Comp Sci Troy NY 12180 USA IBM Corp Network Comp Software Div Res Triangle Pk NC 27709 USA Georgia Inst Technol Coll Comp Atlanta GA 30332 USA Emory Univ Dept Math & Comp Sci Atlanta GA 30322 USA

parallel discrete-event simulation systems (PDES) are used to simulate large-scale applications such as modeling telecommunication networks, transportation grids, and battlefield scenarios. While a large amount of PDES research has focused on employing multiprocessors and multicomputers, the use of networks of workstations interconnected through Ethernet or ATM has evolved into a popular effective platform for PDES. Nonetheless, the development of efficient PDES systems in network computing environments is not without obstacles that severely degrade simulator performance. To better understand how these factors degrade performance as well as develop new algorithms to mitigate them, we investigate the use of graphical visualization to provide insight into performance evaluation and simulator execution. We began with a general-purpose network computing visualization system, PVaniM, and used it to investigate the execution of an advanced version of Time Warp, called Georgia Tech Time Warp (GTW), which executes in network computing environments. Because PDES systems such as GTW are essentially middleware that support their own applications, we soon realized these systems require their own middleware-specific visualization support. To this end we have extended PVaniM into a new system, called PVaniM-GTW by adding middleware-specific views. Our experiences with PVaniM-GTW indicates that these enhancements enable one to better satisfy the needs of PDES middleware than general-purpose visualization systems while also not requiring the development of application-specific visualizations by the end-user. (C) 1999 Elsevier Science B.V. All rights reserved.

关键词： parallel discrete-event simulation visualization network computing time warp

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Effective fault tolerance for agent-based cluster computing

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JOURNAL OF SYSTEMS AND SOFTWARE 1999年第3期48卷 189-196页

作者： Shum, KH Natl Univ Singapore Dept Informat Syst & Comp Sci Harbourlights 098830 Singapore

Long-lived parallel applications running on workstation clusters are vulnerable to single-node or multiple-node failures. Fault recovery is therefore important in avoiding immature program termination. However, much of the runtime overhead imposed by fault tolerance schemes is generally due to the cost of transferring the checkpoint states of applications by disk I/O operations. In this paper, we propose a fault tolerant model in which disk I/O operations are not required because checkpoint states are transferred between replicated parallel applications. We also describe how the resource consumption of the replicated applications can be effective. To achieve this, applications are constructed as computation agents that can reconfigure dynamically according to resource availability. The fault tolerant model has been implemented and tested on a workstation cluster and a Fujitsu AP3000 multiprocessor machine. The measurements of our experiments have showed that efficient fault tolerance can be achieved by replicating parallel applications on workstation clusters. (C) 1999 Elsevier Science Inc. All rights reserved.

关键词： fault tolerance replication checkpointing networks of workstation cluster computing parallel discrete-event simulation

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parallel discrete-event simulation (PDES): a case study in design, development, and performance using SPEEDES 95

Parallel Discrete-Event Simulation (PDES): a case study in d...

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Proceedings of the ninth workshop on parallel and distributed simulation

作者： Frederick Wieland Eric Blair Tony Zukas The MITRE Corporation 7525 Colshire Dr. McLean VA

ISBN: (纸本)9780818671203

Can parallel simulations efficiently exploit a network of workstations? Why haven't PDES models followed standard modeling methodologies? Will the field of PDES survive, and if so, in what form? Researchers in the PDES field have addressed these questions and others in a series of papers published in the last few years [1,2,3,4]. The purpose of this paper is to shed light on these questions, by documenting an actual case study of the development of an optimistically synchronized PDES application on a network of workstations. This paper is unique in that its focus is not necessarily on performance, but on the whole process of developing a model, from the physical system being simulated, through its conceptual design, validation, implementation, and, of course, its performance. This paper also presents the first reported performance results indicating the impact of risk on performance. The results suggest that the optimal value of risk is sensitive to the latency parameters of the communications network.

关键词： performance network of workstations implementation aerospace simulation validation flight simulation aerospace computing communications network SPEEDES discrete event simulation conceptual design parallel discrete-event simulation optimistically synchronized PDES operations research

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Massively parallel and Distributed simulation of a Class of discrete event Systems: A Different Perspective

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ACM Transactions on Modeling and Computer simulation (TOMACS) 1992年第3期2卷 214-238页

作者： Vakili, Pirooz Department of Manufacturing Engineering Boston University Boston MA 02215 44 Cummington Street United States

In this paper we propose a new approach to parallel and distributed simulation of discrete event systems. Most parallel and distributed discrete event simulation algorithms are concerned with the simulation of one “large” discrete event system. In this case the computational intensity is due to the size and complexity of the simulated system. In contrast, we are interested in simulating a “large” number of “medium sized” systems. These are variants of a “nominal system” with different system parameter values or operation policies. The computational intensity in our case is due to the “large” number of simulated variants. Many simulation projects such as factor screening, performance modeling, and optimization require system performance evaluations at many parameter values;and others, we believe, could significantly benefit from them. There is considerable work in the literature on stochastic coupling of trajectories of parametric families of stochastic processes. Our approach can be viewed as the simulation of the coupled trajectories. We use a single clock mechanism that drives all trajectories simultaneously, hence the approach is called Single Clock Multiple System 1992 simulation. The single clock synchronizes all trajectories such that the “same” event occurs at the “same” time at all systems. This synchronization is the basis of our parallel and distributed algorithms. We focus on a particular implementation of the SCMS simulation using the so-called Standard Clock (SC) technique and also on the massively parallel implementation of the SC algorithms on the SIMD Connection Machine. Orders of magnitude of speedup is possible. Furthermore, the possibility of concurrent performance evaluation and comparison at many system parameter values offers new and significant opportunities for performance optimization. © 1992, ACM. All rights reserved.

关键词： event-driven simulation parallel discrete-event simulation speedup

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Mechanisms for User-Invoked Retraction of events in Time Warp

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ACM Transactions on Modeling and Computer simulation (TOMACS) 1991年第3期1卷 219-243页

作者： Lomow, Greg Das, Samir Ranjan Fujimoto, Richard M. Jade Simulations International Corp. Alberta T2M 457 #80 1833 Crowchild Trail N. W. Calgary Canada College of Computing Georgia Institute of Technology Atlanta GA 30332-0280 United States

We examine a primitive that allows application programs to explicitly retract previously scheduled events in Time Warp. Specifically, a simple mechanism for retracting messages is defined, and a correctness proof is presented. Various optimizations to the proposed mechanism are also described. The proposed mechanism is intended to be implemented within the kernel of the Time Warp runtime executive. It is also possible to implement event retraction within the application program itself, without kernel support. Empirical data is presented to compare the performance observed in these two approaches. Based on these studies, we argue that support for a retraction primitive within the Time Warp kernel can significantly improve performance for programs that use event retraction to a moderate or heavy degree. © 1991, ACM. All rights reserved.

关键词： event-driven simulation parallel discrete-event simulation process-oriented simulation retraction of events rollback synchronization methods Time Warp

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