In this paper, we present the implementation of a parallel road traffic. simulation using the concept of Lane Cut Points (LCPs) in the Spider programming environment. LCPs are storage buffers inserted into lane data s...
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ISBN:
(纸本)0769520367
In this paper, we present the implementation of a parallel road traffic. simulation using the concept of Lane Cut Points (LCPs) in the Spider programming environment. LCPs are storage buffers inserted into lane data structures at the road network partition edges. Vehicles enter a partition at the edges from an LCP and exit a partition edge into an LCP at the end of every simulation. step. Spider, a parallel programming environment, which runs on PVM, coordinates the execution of the parallel traffic simulation.
This paper describes a procedure for assigning simulation trials to a set of parallel processors for the purpose of conducting a simulation study, involving a complex simulation model, in near real time. Unlike distri...
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ISBN:
(纸本)0769520367
This paper describes a procedure for assigning simulation trials to a set of parallel processors for the purpose of conducting a simulation study, involving a complex simulation model, in near real time. Unlike distributedsimulation, where a complex simulation model is decomposed and its parts run in a parallel environment, the parallel replications approach discussed here involves running simulation replications to completion for the entire model. The unique element here is that the workload involved in running the simulation study is too time consuming to execute on a single workstation, so that the simulation analyst must utilize computer resources available through the web. New statistical methodology is needed for running a complex simulation study in a web-based, parallel replications environment.
The Grid enables large-scale resource sharing and makes it viable for running large-scale parallel and distributedsimulations. The High Level Architecture (HLA) paradigm provides a software platform and interoperabil...
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ISBN:
(纸本)0769520367
The Grid enables large-scale resource sharing and makes it viable for running large-scale parallel and distributedsimulations. The High Level Architecture (HLA) paradigm provides a software platform and interoperability interface for simulation components to utilize these hardware resources. However, neither the Grid nor the HLA provides mechanism for resource management for parallel and distributedsimulations. It is also noticed that substantial effort is required for writing program that conforms to the Runtime Infrastructure (RTI) requirements because of its complexity. In this paper, we introduce a framework for designing and executing parallelsimulation using the RTI. The framework is also designed to assist load balancing and checkpointing. With the code library from our framework, the modeler is able to complete the design of a parallelsimulation that runs on RTI by specifying the simulation configuration and the handling detail of each event. Our framework incorporates automatic code generation. It also uses Data Distribution Management to route simulation events (interactions) to achieve efficient use of network bandwidth.
We present a new conservative event-synchronization protocol, time-based synchronization, for parallel discrete-event simulation of mobile ad hoc wireless networks. Simulators that use our protocol proceed at a scaled...
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ISBN:
(纸本)0769520367
We present a new conservative event-synchronization protocol, time-based synchronization, for parallel discrete-event simulation of mobile ad hoc wireless networks. Simulators that use our protocol proceed at a scaled version of real time and send messages that correspond only to transmissions in the simulated network. We show that such simulators can maintain a constant execution time even as the sizes of the networks that they simulate grow. Moreover we show that these simulators, when executed on a custom parallel architecture, are capable of simulating many networks faster than real time.
Large-scale parallel discrete event simulations of massive networks, such as the Internet, are "Grand Challenge" problems: packet level simulation of even a small fraction of the Internet would consume the r...
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ISBN:
(纸本)0769519709
Large-scale parallel discrete event simulations of massive networks, such as the Internet, are "Grand Challenge" problems: packet level simulation of even a small fraction of the Internet would consume the resources of the most powerful computers available. We reimplement the SSF Scalable simulation Framework so we can run large-scale network simulations originally written for DaSSF Our implementation, CraySSF is designed for the Cray-MTA, a multi-threaded supercomputer architecture developed specifically to address large-scale computations of the kind that are not easily distributed. This paper describes the architecture, implementation issues, and preliminary performance results on a variety of (stock) serial and parallel architectures.
This paper introduces a technique to control the overhead of time management processes in order to make such mechanisms appropriate for real-time distributedsimulation. A novel message accounting scheme, the offset-e...
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ISBN:
(纸本)0769519709
This paper introduces a technique to control the overhead of time management processes in order to make such mechanisms appropriate for real-time distributedsimulation. A novel message accounting scheme, the offset-epoch method, is presented as a way to increase the efficiency of time management algorithms by eliminating transient messages. A synchronized lower-bound on timestamp (LBTS) computation exploits this efficiency to reduce time management overheads. This approach represents one step in bridging the gap that now exists between analytic and real-time distributedsimulations.
Time-parallelsimulation defines a methodology that can be applied to certain specific simulation problems. In this paper, we present a time-parallel approach for trace-driven simulation of the CSMA/CD protocol. The &...
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ISBN:
(纸本)0769519709
Time-parallelsimulation defines a methodology that can be applied to certain specific simulation problems. In this paper, we present a time-parallel approach for trace-driven simulation of the CSMA/CD protocol. The "memoryless" property of the physical system under moderate traffic loads allows for efficient time-parallelsimulation. We also present two optimization techniques: the estimation of idle points and the incremental fix-up computation. The former can improve the probability that a subtrace begins with a known initial system state. The latter can speedup the fix-up computation that is required when the estimation of the initial state is incorrect.
There is a wide-spread usage of hardware design languages(HDL) to speed up the time-to-market for the design of modern digital systems. Verification engineers can simulate hardware in order to verify its performance a...
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ISBN:
(纸本)0769519709
There is a wide-spread usage of hardware design languages(HDL) to speed up the time-to-market for the design of modern digital systems. Verification engineers can simulate hardware in order to verify its performance and correctness with help of an HDL. However simulation can't keep pace with the growth in size and complexity of circuits and has become a bottleneck of the design process. distributed HDL simulation on a cluster of workstations has the potential to provide a cost-effective solution to this problem. In this paper we describe the design and implementation of DVS, an object-oriented framework for distributed Verilog simulation. Verilog is an HDL which sees wide industrial use. DVS is an outgrowth of Clustered Time Warp, originally developed for logic simulation. The design of the framework emphasizes simplicity and extensibility and aims to accommodate experiments involving partitioning and dynamic load balancing. Preliminary results obtained by simulating a 16bit multiplier are presented.
We present a classification that groups lookback into four types: direct strong lookback, universal strong lookback, direct weak lookback, and universal weak lookback. They are defined in terms of absolute and dynamic...
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ISBN:
(纸本)0769519709
We present a classification that groups lookback into four types: direct strong lookback, universal strong lookback, direct weak lookback, and universal weak lookback. They are defined in terms of absolute and dynamic impact times. We discuss relationships between lookback types by considering,when rollbacks and/or anti-messages are avoided From different types of lookback, we also derive three optimization techniques for optimistic simulation and point out their advantages over lazy cancellation. Finally, we show that all four types of lookback exist in the PCS network simulation and can be exploited by either lookback-based or optimistic protocols.
This paper presents the design of a system that supports execution of HLA distributed interactive simulations in an unreliable Grid environment. The design of the architecture is based on the OGSA concept that allows ...
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ISBN:
(纸本)0769520367
This paper presents the design of a system that supports execution of HLA distributed interactive simulations in an unreliable Grid environment. The design of the architecture is based on the OGSA concept that allows for modularity and compatibility with Grid Services already being developed. First of all, we focus on the part of the system which is responsible for migration of a HLA-connected component or components of the distributed application in the Grid environment. We present a runtime support library for easily plugging HLA simulations into the Grid Services Framework. We also present the impact of execution management (namely migration) on overall system performance.
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