A study is presented in applying optimistic parallel discrete event simulation techniques using reverse execution to perform instruction-level simulations of distributed memory multi-processor systems. A static progra...
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ISBN:
(纸本)9780769528984
A study is presented in applying optimistic parallel discrete event simulation techniques using reverse execution to perform instruction-level simulations of distributed memory multi-processor systems. A static program analysis approach is described to optimize pre-processed simulated applications in order to remove certain overheads associated with forward event execution and to enable reversible execution. Reverse execution of floating point operations are also considered. Preliminary performance measurements are presented indicating this approach offers promise in speeding up parallel multi-processor simulations.
We examine a parallel processing method for simulations of large-scale networks with a hybrid traffic representation combining both a time-stepped fluid model and a discrete-event packet-oriented model. This method be...
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ISBN:
(纸本)9780769528984
We examine a parallel processing method for simulations of large-scale networks with a hybrid traffic representation combining both a time-stepped fluid model and a discrete-event packet-oriented model. This method benefits from the observation that the time it takes to propagate-fluid characteristics along the path taken by the traffic flows has a lower bound equal to the minimum link delay as manifested by the governing ordinary differential equations (ODEs). A better lookahead can thus be used to allow parallelsimulation of the hybrid model to run without more synchronization overhead than the corresponding discrete-event packet-oriented model. We derive an analytical model comparing the fluid model and the packet-oriented model both for sequential and parallelsimulations. We demonstrate the benefit of the parallel hybrid model through a series of simulation experiments of a large-scale network consisting of over 170,000 hosts and 1.6 million traffic flows on a small parallel cluster.
The Local Time Warp (LTW) model was one of the novel approaches to distributedsimulation presented in early 90s. While several similar schemes had emerged afterwards, no implementation and performance analysis of LTW...
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ISBN:
(纸本)9780769528984
The Local Time Warp (LTW) model was one of the novel approaches to distributedsimulation presented in early 90s. While several similar schemes had emerged afterwards, no implementation and performance analysis of LTW were offered. This paper provides an implementation and performance analysis of the Local Time Warp model on a Beowulf Cluster using Message Passing Interface (MPI). Cluster computing matches well with the Local Time Warp model due to its partitioning of the simulation entities and assigning them to clusters of processors. This paper presents a distributedsimulation engine called BG-LTW which is a clustered-based implementation of the model. Further, the implementation features and its performance are provided. The obtained results suggest that for large-scale simulations local time warp outperforms its global counterpart.
simulation is a low cost and safe alternative to solve complex problems in various areas. To promote reuse and interoperability of simulation applications and link geographically dispersed simulation components, distr...
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ISBN:
(纸本)9780769528984
simulation is a low cost and safe alternative to solve complex problems in various areas. To promote reuse and interoperability of simulation applications and link geographically dispersed simulation components, distributedsimulation was introduced. The High Level Architecture (HLA) is the IEEE standard for distributedsimulation. To optimize communication efficiency between simulation components, HLA defines a Data Distribution Management (DDM) service group for filtering out unnecessary data exchange. It relies on the computation of overlap between update and subscription regions, which is called matching. In this paper we propose an efficient sort-based DDM matching algorithm for HLA applications with a large spatial environment. A theoretical analysis of our algorithm concludes that it should have good storage and computational scalability. The experimental results have verified the theoretical conclusions by showing that our algorithm has much less storage requirement than the original sort-based matching algorithm and generally has the best computational performance when compared with region-based and the original sort-based matching algorithms.
High-fidelity simulations of mixed wired and wireless network systems are dependent on detailed simulation models, especially in the lower layers of the network stack. However detailed modeling can result in prohibiti...
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ISBN:
(纸本)9780769528984
High-fidelity simulations of mixed wired and wireless network systems are dependent on detailed simulation models, especially in the lower layers of the network stack. However detailed modeling can result in prohibitive computation cost. In recent years, commercial graphics cards (GPUs) have drawn attention from the general computing community due to the superior computation capability. In this paper we present our experience with using commercial graphics cards to speed up execution of network simulation models. First, we propose a general simulation framework supporting GPU-accelerated simulation models. Software abstraction is designed to facilitate the use and development of GPU-based models. Second, we implement and evaluate two simulation models using GPUs. We observed that using the GPUs can yield significant performance improvements for large configurations of the model, as compared with pure CPU-based computations, with no degradation in the accuracy of the results. This benefit is particularly impressive for models that include significant data parallel computations. However we also observed that the overhead introduced by GPUs make them less effective in improving execution time of other net-work models. This study suggests that besides parallel computing and grid computing, network simulations can also be scaled by reaping computation capability of GPUs and, potentially, other external computational hardware.
In the design and analysis of discrete event systems, the validation of their models is often addressed via simulation. Petri nets have been applied widely Lookahead computation is a good method that improves the dist...
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ISBN:
(纸本)9780769529097
In the design and analysis of discrete event systems, the validation of their models is often addressed via simulation. Petri nets have been applied widely Lookahead computation is a good method that improves the distributedsimulation performance of Timed Transition Petri Nets (TTPN). The approach is based on a part of optimism computed on the prediction time each logical process can determine for its advancement. Timed Petri nets meet these requirements, and use the lookahead to analyze the TTPN model for finding the concurrency and blocking structure, thereby making certain the logical process (LP). Based on the specialties of lookahead, the lookahead was applied in parallelsimulation, and acquire the sufficient condition about the TTPN model existing concurrency According to the condition parallel program can be partitioned into several logical processes, and the partition algorithm that can decide quickly the mapping project on the mapping process-processor is presented.
The paper investigates some important transport layer algorithms for wireless sensor networks. On the basis of the single-path-based distributed TCP caching, which work badly when some node on the path be down, adopt ...
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ISBN:
(纸本)0769529097
The paper investigates some important transport layer algorithms for wireless sensor networks. On the basis of the single-path-based distributed TCP caching, which work badly when some node on the path be down, adopt multi-path routing on the network layer and distributed TCP caching on the transport layer to enhance transport reliability. From the simulation results, it improves overall performance in term of end-to-end transport delay comparing with the original DTC algorithm and loads are distributed among the intermediate nodes. And then address some open issues as the research prospects.
As High Level Architecture (HLA) standard widely used in underwater warfare simulation applications, it is imperative that we should meet the need for the adaptation to the changing warfare requirements and improve de...
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ISBN:
(纸本)9780769529097
As High Level Architecture (HLA) standard widely used in underwater warfare simulation applications, it is imperative that we should meet the need for the adaptation to the changing warfare requirements and improve development efficiency and reusability of simulation software, especially when developing a federate, known as a node in HLA-based distributedsimulation. To address this problem, we present a dynamic reconfigurable adaptive software architecture for federate in this paper. The architecture has capability of self-adaptation to simulation requirements, and separates function realization from configuration control. It is composed of four layers, interface communication, requirement management, adaptation management and function realization. In this architecture, we partition the federate into several functional parts in terms of a definite granularity with Component-Based Software Development (CBSD) methodology. The architecture can adjust dynamically the configuration of federate to the new requirements while the simulation requirements change. Finally, we take a general sonar federate as an example to illustrate the presented architecture's support for adaptation.
A difference scheme for noise removal based on four-order partial differential equations is suggested. It can approximate actual image while preserving edges and avoiding blocky effects in image processing. Numerical ...
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ISBN:
(纸本)0769529097
A difference scheme for noise removal based on four-order partial differential equations is suggested. It can approximate actual image while preserving edges and avoiding blocky effects in image processing. Numerical results are demonstrated its efficiency and the better choice of parameters.
Advances in the design, modeling and simulation of parallel processing systems provide significant research opportunities which lead to improvements on the speed, performance, fault tolerance, flexibility and cost-eff...
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ISBN:
(纸本)9780769528410
Advances in the design, modeling and simulation of parallel processing systems provide significant research opportunities which lead to improvements on the speed, performance, fault tolerance, flexibility and cost-effectiveness of distributed systems. Several parameters determine the suitability of the system architecture for a given application. However Average Routing Distance (ARD) is perhaps one of the most important parameters in performance evaluation of parallel processing systems. To this effect, all mathematical modeling and simulation of ARD and Visit Ratio for a class of parallel processing systems are presented.
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