parallelising sequential discrete event simulation programs is often a tedious process, with no guarantee for speedup. This paper describes a performance analyser tool developed to predict the execution performance of...
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This paper provides an overview of the WarpIV simulation Kernel that was designed to be an initial implementation of the Standard simulation Architecture (SSA). WarpIV is the next generation replacement for the Synchr...
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One of the fundamental challenges for Peer-to-Peer (P2P) systems is the ability to manage risks involved in interacting and collaborating with priorly unknown and potentially malicious parties. Reputation-based trust ...
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ISBN:
(纸本)0769524249
One of the fundamental challenges for Peer-to-Peer (P2P) systems is the ability to manage risks involved in interacting and collaborating with priorly unknown and potentially malicious parties. Reputation-based trust management can mitigate this risk by deriving the trustworthiness of a certain peer from that peer's behavior history. However the existing reputation systems do not provide adequate reaction to quick changes in peers' behavior raising serious concerns regarding their effectiveness in coping with dynamic malicious peers. In this paper we investigate the requirements on the dynamics of trust in P2P systems and propose a versatile trust metric which satisfies these requirements. In particular, our proposed metric is capable to detect and penalize both the sudden changes in peers' behavior and their potential oscillatory malicious behavior Moreover, our metric is flexible to implement different types of trust dynamics. We evaluate our metric through simulation and show its unique features and advantages over the existing metrics.
This paper describes a method for evolutionary component-based development of families of parallel programs to attain performance goals on multiple execution environments for multiple family instances and an implement...
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ISBN:
(纸本)1595930876
This paper describes a method for evolutionary component-based development of families of parallel programs to attain performance goals on multiple execution environments for multiple family instances and an implementation of the method. It is based upon combining component-oriented development with integration of parallel/distributed execution and parallel/distributedsimulation. Each component may have multiple representations at multiple levels of realization from analytical timing models to production code. Each component is encapsulated with an associative interface specifying its properties and behaviors which enables distinguishing among different implementations (or abstractions) of the same functional behavior which may have different performance behavior. Evolutionary development evolves a program from an abstract performance model to a complete program and may continue evolution during runtime. Performance can be estimated at any stage of realization. The implementation is a compiler which composes parallel/distributed programs from components encapsulated with associative interfaces and a runtime system which supports integrated execution/simulation of parallel programs composed from components at different levels of abstraction and program evolution at runtime by component replacement. Case studies in the application of the evolutionary development method including performance results are given. Copyright 2005 ACM.
Scalable and efficient network simulation methods are the method of choice for evaluating and verifying wireless network protocols on a moderate to large scale. This need becomes obvious when simulating very large-sca...
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In this paper, an efficient distributed heuristic-based algorithm is presented, which is based on joint distance-counter threshold scheme. It features a distributed manner by each node in the network needing no global...
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ISBN:
(纸本)3540296395
In this paper, an efficient distributed heuristic-based algorithm is presented, which is based on joint distance-counter threshold scheme. It features a distributed manner by each node in the network needing no global information. Each node in an ad hoc network receives the message from its neighbors and decides whether to operate retransmitting or not according to the signal strength and times of the receiving messages. The algorithm has superiority such as reliability, rebroadcast saving, less communication overhead for broadcasting task, localized and parameter-less behaviors, so it is easy to operate and possesses a good performance in mobile ad hoc communication environments. A comparison with several other existing algorithms is conducted. It shows by simulation results that the new algorithm is more efficient than others.
The proceedings contain 14 papers. The topics discussed include: performance issues in video streaming environments;design and testing of scalable web-based systems with performance constraints;models of dynamic web c...
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ISBN:
(纸本)0769524478
The proceedings contain 14 papers. The topics discussed include: performance issues in video streaming environments;design and testing of scalable web-based systems with performance constraints;models of dynamic web content;performance modeling of P2P file sharing applications;performance model building of pervasive computing;design and performance evaluation of mechanisms for mobile-devices handoff forecast;efficient analysis algorithms for parametric fault trees;a tool set for modeling and simulation of robotic workcells;software performance analysis in UML models;scalable and efficient parallel and distributedsimulation of complex, dynamic and mobile systems;and towards transparent optimistic synchronization in HLA.
Scalable and efficient network simulation methods are the method of choice for evaluating and verifying wireless network protocols on a moderate to large scale. This need becomes obvious when simulating very large-sca...
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ISBN:
(纸本)0769523838
Scalable and efficient network simulation methods are the method of choice for evaluating and verifying wireless network protocols on a moderate to large scale. This need becomes obvious when simulating very large-scale wireless networks such as emerging ad hoc sensor networks in which the number of nodes can be the order of thousands or more, and with very high node density. Unfortunately, simulation of such large-scale wireless networks often requires excessively large amounts of computing resources and can be slow to complete. One approach to achieving higher performance in a large-scale network simulation is the use of parallel or distributedsimulation techniques. However the efficient distributedsimulation of wireless ad hoc networks is still a daunting task. Therefore, we turn our attention to more traditional sequential simulation methods, and seek to reduce the overhead incurred in the Medium Access Control (MAC) state update propagation between wireless nodes. We introduce a novel method called LAMP (LAzy MAC state uPdate), that substantially reduces this overhead, with no loss of accuracy. Using our wireless network simulation tool, we compare the efficiency of the LAMP approach to the more traditional approach, and show a performance improvement of up to a factor of eight, with no loss of accuracy.
Semantic caching is very attractive for use in distributed computing environments based on historical queries and their descriptions, one of whose important issues is how to best maintain semantic caching using a cohe...
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ISBN:
(纸本)3540296395
Semantic caching is very attractive for use in distributed computing environments based on historical queries and their descriptions, one of whose important issues is how to best maintain semantic caching using a coherency control scheme. With the object of applying semantic caching into practice, the cache coherency problems including the data between the server and its caching as well as the cached data and their semantic descriptions are analyzed. This paper presents conflicts existing in semantic caching and their formal definitions, proposes the semantic caching model, and coherency control scheme, meanwhile derives update list optimization algorithm adopted in server and coherency control algorithm used in clients. Finally, the performance of the semantic caching coherency control scheme is examined and analyzed through a simulation study in detail.
Some multimedia content may be divisible into independently routable components, e.g. audio and video flows. As a result media content adaptation services may be linked in serial, parallel and hybrid configurations to...
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