The proceedings contains 76 articles. Topics discussed include systems, networking, distributedsimulation, queueing systems, multiprocessor architecture, modeling techniques, parallel systems. Tools, processors, network and system simulation, optimizing parallel programs, petri nets, neural networks and genetic algorithms, real time systems and systems modelling.
In this paper we discuss new synchronization algorithms for parallel and distributed Discrete Event simulations (PDES) which exploit the capabilities and behavior of the underlying communications network. Previous wor...
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In this paper we discuss new synchronization algorithms for parallel and distributed Discrete Event simulations (PDES) which exploit the capabilities and behavior of the underlying communications network. Previous work in this area has assumed the network to be a Black Box which provides a one-to-one, reliable and in-order message passing paradigm. In our work, we utilize the Broadcast capability of the ubiquitous Ethernet for synchronization computations, and both unreliable and reliable protocols for message passing, to achieve more efficient communications between the participating systems. We describe two new algorithms for computation of a distributed snapshot of global reduction operations on monotonically increasing values. The algorithms require O(N) messages (where N is the number of systems participating in the snapshot) in the normal case. We specifically target the use of this algorithm for distributed discrete event simulations to determine a global lower bound on time-stamp (LBTS), but expect the algorithm has applicability outside the simulation community.
We simulate ballistic particle deposition wherein a large number of spherical particles are 'dropped' vertically over a planar horizontal surface. Upon first contact (with the surface or with a previously depo...
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We simulate ballistic particle deposition wherein a large number of spherical particles are 'dropped' vertically over a planar horizontal surface. Upon first contact (with the surface or with a previously deposited particle) each particle stops. This model helps material scientists to study the adsorption and sediment formation [1]. The model is sequential, with particles deposited one by one. We have found an equivalent formulation using a continuous time random process and we simulate the latter in parallel using a method similar to the one previously employed for simulating Ising spins [2]. We augment the parallel algorithm for simulating Ising spins with several techniques aimed at the increase of efficiency of producing the particle configuration and statistics collection. Some of these techniques are similar to [3], [4], and [5]. We implement the resulting algorithm on a 16K PE MasPar MP-1 and a 4K PE MasPar MP-2. The parallel code runs on MasPar computers two orders of magnitude faster than an optimized sequential code runs on a fast workstation.
A master/worker paradigm for executing large-scale parallel discrete event simulation programs over network-enabled computational resources is proposed and evaluated. In contrast to conventional approaches to parallel...
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The proceedings contain 69 papers. The topics discussed include: exploiting the parallel divide-and-conquer method to solve the symmetric tridiagonal eigenproblem;biological sequence analysis on distributed-shared mem...
ISBN:
(纸本)0818683325
The proceedings contain 69 papers. The topics discussed include: exploiting the parallel divide-and-conquer method to solve the symmetric tridiagonal eigenproblem;biological sequence analysis on distributed-shared memory multiprocessors;scheduling tasks in DAG to heterogeneous processor system;effective scheduling in a mixed parallel and sequential computing environment;distributed computation in a three-dimensional mesh with communication delays;automatic performance evaluation of parallel programs;architecture-dependent partitioning of dependence graphs;modeling and simulation of integrated modular avionics;improving parallel computer communication: dynamic routing balancing;using channel pipelining in reconfigurable interconnection networks;and exploiting write semantics in implementing partially replicated casual objects.
This paper is a reminder of the danger of allowing `risk' when synchronizing a parallel discrete-event simulation: a simulation code that runs correctly on a serial machine may, when run in parallel, fail catastro...
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This paper is a reminder of the danger of allowing `risk' when synchronizing a parallel discrete-event simulation: a simulation code that runs correctly on a serial machine may, when run in parallel, fail catastrophically. This can happen when Time Warp presents an `inconsistent' message to an LP, a message that makes absolutely no sense given the LP's state. Failure may result if the simulation modeler did not anticipate the possibility of this inconsistency. While the problem is not new, there has been little discussion of how to deal with it;furthermore the problem may not be evident to new users or potential users of parallelsimulation. This paper shows how the problem may occur, and the damage it may cause. We show how one may eliminate inconsistencies due to lagging rollbacks and stale state, but then show that so long as risk is allowed it is still possible for an LP to be placed in a state that is inconsistent with model semantics, again making it vulnerable to failure. We finally show how simulation code can be tested to ensure safe execution under a risk-free protocol. Whether risky or risk-free, we conclude that under current practice the development of correct and safe parallelsimulation code is not transparent to the modeler;certain protections must be included in model code or model testing that are not rigorously necessary if the simulation were executed only serially.
The proceedings contain 18 papers. The topics discussed include: new approaches to protein functional inference and ligand screening with application to the human kinome;federate fault tolerance in HLA-based simulatio...
ISBN:
(纸本)9781424472918
The proceedings contain 18 papers. The topics discussed include: new approaches to protein functional inference and ligand screening with application to the human kinome;federate fault tolerance in HLA-based simulation;continuous matching algorithm for interest management in distributed virtual environments;a methodology to predict the performance of distributedsimulations;optimizing a business process model by using simulation;selecting simulation algorithm portfolios by genetic algorithms;on validation of semantic composability in data-driven simulation;integrative models of the hepatitis C virus infection: modeling wicked problems;functional level hardware simulation with pull-model data flow;flow: a stream processing system simulator;reversible parallel discrete-event execution of large-scale epidemic outbreak models;validation of radio channel models using an anechoic chamber;and explicit spatial scattering for load balancing in conservatively synchronized parallel discrete-event simulations.
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.
A great deal of research in the area of distributed discrete event simulation has focussed on evaluating the performance of variants of conservative and optimistic methods on different types of applications. Applicati...
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ISBN:
(纸本)1565550277
A great deal of research in the area of distributed discrete event simulation has focussed on evaluating the performance of variants of conservative and optimistic methods on different types of applications. Application characteristics like lookahead, communication patterns, etc. have been found to affect the suitability of a specific protocol to simulate a given model. For many systems, it may be the case that different subsystems possess contradictory characteristics such that whereas some subsystems may be simulated efficiently using a conservative protocol, others may be more amenable to optimistic methods. Furthermore, the suitability of a protocol for a given subsystem may change dynamically. We propose a parallelsimulation protocol that allows different parts of a system to be simulated using different protocols, allowing these protocols to be switched dynamically. A proof of correctness is presented, along with some preliminary performance discussion.
In this contribution an implemented prototype of an object server on a parallel computer is described. In the first phase a model iras been proposed and simulated in Ada'95. Based on obtained experiences with run-...
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ISBN:
(纸本)0818681489
In this contribution an implemented prototype of an object server on a parallel computer is described. In the first phase a model iras been proposed and simulated in Ada'95. Based on obtained experiences with run-time features of the simulation program a corresponding prototype has been implemented in C++, tested, and the obtained results have been compared with results of the simulation.
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