The paper discusses the parallelisation of complex three-dimensional software for nonlinear analysis of R/C buildings structures. It presents a comparative study for handling the nonlinear response in different parall...
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The paper discusses the parallelisation of complex three-dimensional software for nonlinear analysis of R/C buildings structures. It presents a comparative study for handling the nonlinear response in different parallel architectures. The nonlinear finite element model adopts a fiber decomposition approach for the cross-section of beam elements to capture nonlinear behavior of concrete. The parallelisation strategy is designed regarding three items: the numerical stability of the nonlinear procedure, the parallel sparse equation solver and the application on heterogeneous hardware: dedicated shared memory machines or clusters of networked personal computers. (C) 2002 Published by Elsevier Science Ltd.
In this paper we provide a view of the design and development activity concerning advanced environments for parallel and distributed computing. We start from assessing the main issues driving this research track, in t...
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In this paper we provide a view of the design and development activity concerning advanced environments for parallel and distributed computing. We start from assessing the main issues driving this research track, in the areas of hardware and software technology and of applications. Then, we identify some key concepts, that can be considered as common guidelines and goals in the development of modem advanced environments, and we come up with a "classification" of these environments into two main classes: programming environments and problems solving environments. Both classes are widely discussed, in light of the key concepts previously outlined, and several examples are provided, in order to give a picture of the current status and trends. (C) 2002 Elsevier Science B.V. All rights reserved.
The development of intelligent transportation systems (ITS) and the resulting need for the solution of a variety of dynamic traffic network models and management problems require faster-than-real-time computation of s...
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The development of intelligent transportation systems (ITS) and the resulting need for the solution of a variety of dynamic traffic network models and management problems require faster-than-real-time computation of shortest path problems in dynamic networks. Recently, a sequential algorithm was developed to compute shortest paths in discrete time dynamic networks from all nodes and all departure times to one destination node. The algorithm is known as algorithm DOT and has an optimal worst-case running-time complexity. This implies that no algorithm with a better worst-case computational complexity can be discovered. Consequently, in order to derive algorithms to solve all-to-one shortest path problems in dynamic networks, one would need to explore avenues other than the design of sequential solution algorithms only. The use of commercially-available high-performance computing platforms to develop parallel implementations of sequential algorithms is an example of such avenue. This paper reports on the design, implementation, and computational testing of parallel dynamic shortest path algorithms. We develop two shared-memory and two message-passing dynamic shortest path algorithm implementations, which are derived from algorithm DOT using the following parallelization strategies: decomposition by destination and decomposition by transportation network topology. The algorithms are coded using two types of parallelcomputing environments: a message-passing environment based on the parallel virtual machine (PVM) library and a multi-threading environment based on the SUN Microsystems Multi-Threads (MT) library. We also develop a time-based parallel version of algorithm DOT for the case of minimum time paths in FIFO networks, and a theoretical parallelization of algorithm DOT on an ‘ideal’ theoretical parallel machine. Performances of the implementations are analyzed and evaluated using large transportation networks, and two types of parallelcomputing platforms: a distr
We introduce a new performance metric, called Load Balancing Factor (LBF), to assist programmers with evaluating different tuning alternatives. The LBF metric differs from traditional performance metrics since it is i...
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We introduce a new performance metric, called Load Balancing Factor (LBF), to assist programmers with evaluating different tuning alternatives. The LBF metric differs from traditional performance metrics since it is intended to measure the performance implications of a specific tuning alternative rather than quantifying where time is spent in the current version of the program. A second unique aspect of the metric is that it provides guidance about moving work within a distributed or parallel program rather than reducing it. A variation of the LBF metric can also be used to predict the performance impact of changing the underlying network. The LBF metric is computed incrementally and online during the execution of the program to be tuned. We also present a case study that shows that our metric can accurately predict the actual performance gains for a test suite of six programs.
Shelterbelts or windbreaks were used for centuries to reduce wind speed, to control heat and moisture transfer and pollutant diffusion, to improve climate and environment, and to increase crop yields;but only within t...
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Shelterbelts or windbreaks were used for centuries to reduce wind speed, to control heat and moisture transfer and pollutant diffusion, to improve climate and environment, and to increase crop yields;but only within the last few decades have systematic studies considered the aerodynamics and shelter mechanisms of shelterbelts and windbreaks. This review examines recent modeling and numerical simulation studies as well as the mechanisms that control flow and turbulence around shelterbelts and windbreaks. We compare numerical simulations with experimental data and explain the relationships between sheltering effects and the structure of shelterbelts and windbreaks. We discuss how and why the desired effects are achieved by using numerical analysis. This chapter begins with the derivation of a general equation set for porous shelterbelts and windbreaks;the numerical model and simulation procedure are developed;unseparated and separated flows are predicted and characterized;the momentum budget and shelter mechanisms are analyzed;the effects of wind direction, density, width, and three dimensionality of shelterbelt structure on flow and turbulence are systematically described. Recent modeling and simulation of heat flux and evapotranspiration are also summarized. Finally, we discuss the use of highperformance distributed and parallelcomputing as well as clusters of networked workstations to enhance performance of the model applied to simulations of shelterbelts and windbreaks.
In this contribution, recent architectural approaches and roofs for local-area and wide-area computing ruing clusters of sewers, workstations, and PCs as multicomputers (i.e. parallelcomputing irt workstation cluster...
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ISBN:
(纸本)0769509878;0769509886
In this contribution, recent architectural approaches and roofs for local-area and wide-area computing ruing clusters of sewers, workstations, and PCs as multicomputers (i.e. parallelcomputing irt workstation clusters) are classified and described. The goat of such systems is to concentrate available computing resources To solve computing problems. A special focus of this contribution is a description of recent research in the field of cost-efficient parallelcomputing with standard component multicomputer systems, concentrating on locally organized clusters for local-area computing and on wide-area multiclusters (hyperclusters or clusters of clusters) for wide-ar-ea computing. Selected examples are given demonstrating the improvement through high-speed interconnection networks and optimized protocol system architectures in local-area systems and optimized organizations in wide-area systems.
parallel and distributed computing is becoming increasingly mainstream driven both by the widespread availability of commodity small-scale symmetric multiprocessors and high-performance cluster platforms, as well as t...
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parallel and distributed computing is becoming increasingly mainstream driven both by the widespread availability of commodity small-scale symmetric multiprocessors and high-performance cluster platforms, as well as the growing use of parallelism and distribution in networked applications such as image recognition, media processing, virtual reality, and telepresence. However, many of these applications impose son timeliness and output quality constraints on top of the traditional performance requirements, necessitating efficient, predictable management of system resources. Existing techniques are inadequate to simultaneously support these twin requirements of efficiency and predictability. In this paper, we propose a novel approach for increasing system efficiency while meeting application timeliness and quality constraints. Our approach exploits the application tunability found in many general-purpose computations. Tunability refers to an application's ability to trade off resource requirements over several dimensions including time, quality, and resource type;the resulting flexibility enables the underlying resource management system to choose an application operating point best suited to available resource characteristics. We describe language and scheduler extensions to support tunability in the MILAN metacomputing environment and then systematically characterize performance benefits of tunability using a parameterizable task system. Our. results show that application tunability is easily expressible and can significantly improve resource utilization. (C) 2000 Academic Press.
A new class of interconnection networks, the hypernetworks, has been proposed recently. Hypernetworks are characterized by hypergraphs. Compared with Feint-to-point networks, they allow for increased resource-sharing ...
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A new class of interconnection networks, the hypernetworks, has been proposed recently. Hypernetworks are characterized by hypergraphs. Compared with Feint-to-point networks, they allow for increased resource-sharing and communication bandwidth utilization, and they are especially suitable for optical interconnects. In this paper, we propose a scheme for deriving new hypernetworks using hypergraph duals. As an example, we investigate the dual, K-n*, of the n-vertex complete graph K-n and show that it has many desirable properties. We also present a set of fundamental data communication algorithms for K-n*. Our results indicate that the K-n* hypernetwork is a useful and promising interconnection structure for high-performance parallel and distributed computing systems. (C) 2000 Academic Press.
Project Bayanihan is developing the idea of volunteer computing, which seeks to enable people to form very large parallelcomputing networks very quickly by using ubiquitous and easy-to-use technologies such as web br...
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Project Bayanihan is developing the idea of volunteer computing, which seeks to enable people to form very large parallelcomputing networks very quickly by using ubiquitous and easy-to-use technologies such as web browsers and Java. By utilizing Java's object-oriented features, we have built a flexible software framework that makes it easy for programmers to write different volunteer computing applications, while allowing researchers to study and develop the underlying mechanisms behind them. In this paper, we show how we have used this framework to write master-worker style applications, and to develop approaches to the problems of programming interface, adaptive parallelism, fault-tolerance, computational security, scalability, and user interface design. (C) 1999 Elsevier Science B.V. All rights reserved.
This paper presents the design philosophy and implementation of the BALANCE system. BALANCE is a flexible, network independent and computer architecture independent load balancing system which allows the building of r...
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