this paper describes the design and implementation of a solution to the constrained 2-D cutting stock problem on a cluster of workstations. the constrained 2-D cutting stock problem is an irregular problem with a dyna...
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ISBN:
(纸本)0818675829
this paper describes the design and implementation of a solution to the constrained 2-D cutting stock problem on a cluster of workstations. the constrained 2-D cutting stock problem is an irregular problem with a dynamically modified global data set and irregular amounts and patterns of communication. A replicated data structure is used for the parallel solution since the ratio of reads to writes is known to be large. Mutual exclusion and consistency are maintained using a token-based lazy consistency mechanism, and a randomized protocol for dynamically balancing the distributed work queue is employed. Speedups are reported for three benchmark problems executed on a cluster of workstations interconnected by a 10 Mbps Ethernet.
An efficient adaptive approach for parallel and distributed Simulation (PADS) is formalized and implemented. the Aggressive Adaptive-Risk (AAR) approach aims at reducing cascading rollbacks in large and complex simula...
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An efficient adaptive approach for parallel and distributed Simulation (PADS) is formalized and implemented. the Aggressive Adaptive-Risk (AAR) approach aims at reducing cascading rollbacks in large and complex simulations by clustering optimistic logical processes on each processor, and providing these processes the ability to adjust their degree of risk, at run time, to a good operating point based on observed behavior. the AAR approach is used to develop the Clustered Adaptive distributed Simulator (CADS) which is implemented on a network of workstations. Details of the CADS implementation are described. Performance results for large synthetic loads are reported and compared to those obtained for the Time Warp optimistic technique.
Coupling PC-based commodity technology withdistributedcomputing methodologies provides an important advance in the development of single-user dedicated systems. Beowulf is a class of experimental parallel workstatio...
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ISBN:
(纸本)0818675829
Coupling PC-based commodity technology withdistributedcomputing methodologies provides an important advance in the development of single-user dedicated systems. Beowulf is a class of experimental parallel workstations developed to evaluate and characterize the design space of this new operating point in price-performance. A key factor determining the realizable performance under real-world workloads is the means devised for interprocessor communications. A study has been performed to characterize a family of interconnect topologies feasible with low cost mass market network technologies. Behavior sensitivities to packet size and traffic density are determined. Findings are presented which compare more complex segmented topologies to the earlier parallel 'channel bonded' scheme. It is shown that in many circumstances the more complex topologies perform better, and in some circumstances software routing techniques compare favorably to more expensive hardware switch mechanisms.
In this paper a modified parallel Jacobi-conditioned conjugate gradient (CG) method is proposed for solving linear elastic finite element system of equations. the conventional element-by-element and diagonally conditi...
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In this paper a modified parallel Jacobi-conditioned conjugate gradient (CG) method is proposed for solving linear elastic finite element system of equations. the conventional element-by-element and diagonally conditioned approaches are discussed with respect to parallel implementation on distributed memory MIMD architectures. the effects of communication overheads on the efficiency of the parallel CG solver are considered and it is shown that for the efficient performance of a parallel CG solver, the interprocessor communication has to be carried out concurrently. A concurrent communication scheme is proposed by relating the semi-bandwidth of the stiffness matrix withthe number of independent degrees of freedom and the number of processors and inducing directionalization of communication within the processor pipeline. Withthe aid of two examples the effectiveness of the proposed method is demonstrated showing that the cost of communication remains low and relatively insensitive to the increase in the number of processors. Copyright (C) 1996 Civil-Comp Limited and Elsevier Science Limited.
An efficient parallelisation of an existing sequential method for obtaining the eigenvalues of a structure by an exact analytical procedure is presented. Results are given which illustrate finding the undamped natural...
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An efficient parallelisation of an existing sequential method for obtaining the eigenvalues of a structure by an exact analytical procedure is presented. Results are given which illustrate finding the undamped natural frequencies of a rigidly jointed plane frame, but the method is also applicable to buckling problems and to other types of structure. the parallel method is suited to bothdistributed and shared-memory parallel machines. It seeks to equate the workload of each processor (node) by initially sharing out the work and by subsequently passing work from working nodes to idle nodes. Experimental runs on an nCUBE2 computer show that reasonably high levels of efficiency are possible. Copyright (C) Civil-Comp Limited and Elsevier Science Limited.
the remote procedure call (RPC) paradigm has been a favorite of programmers who write distributed programs because RPC uses a familiar procedure call abstraction as the sole mechanism of remote operation. the abstract...
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the remote procedure call (RPC) paradigm has been a favorite of programmers who write distributed programs because RPC uses a familiar procedure call abstraction as the sole mechanism of remote operation. the abstraction helps to simplify programming tasks, but this does not mean that the resulting program's RPC-based flow of control will be anything close to ideal for high performance. the purpose of our research is to provide a source-level transformation framework as an alternative way to implement an RPC-based distributed program, so that the code can be optimized through program analysis techniques.
this paper presents a distributed Genetic Algorithm implementation for obtaining good quality consistent results for different ordering problems. Most importantly, the solution found by the proposed distributed GA is ...
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this paper presents a distributed Genetic Algorithm implementation for obtaining good quality consistent results for different ordering problems. Most importantly, the solution found by the proposed distributed GA is not only of high-quality but also robust and does not require fine-tuning of the probabilities of crossover and mutation. In addition, implementation of the distributed GA is simple and does not require the use of any specialized, expensive hardware. Fault tolerance has also been provided by dynamic reconfiguration of the distributed system in the event of a process or machine failure. the effectiveness of using a simple crossover scheme withdistributed GA is demonstrated by solving three variations of the Traveling Salesman Problem (TSP).
In this paper a model for scheduling in wide-area systems is described. the model is federated and utilizes a collection of local site schedulers that control the use of their resources. the wide-area scheduler consul...
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ISBN:
(纸本)0818675829
In this paper a model for scheduling in wide-area systems is described. the model is federated and utilizes a collection of local site schedulers that control the use of their resources. the wide-area scheduler consults the local site schedulers to obtain candidate machine schedules. A set of issues and challenges inherent to wide-area scheduling are also described and the proposed model is shown to address many of these problems. A distributed algorithm for wide-area scheduling is presented and relies upon information made available about the resource needs of user jobs. the wide-area scheduler will be implemented in Legion, a wide-area computing system developed at the University of Virginia.
this paper describes the design of a distributed system built using Java that supports peer-to-peer communication among processes spread across a network. We identify the requirements of a software layer that supports...
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this paper describes the design of a distributed system built using Java that supports peer-to-peer communication among processes spread across a network. We identify the requirements of a software layer that supports distributedcomputing, and we propose a design that meets those requirements. Our primary concerns are (1) the identification, specification, and implementation of software components that can be composed in different ways to develop correct distributed applications;(2) reasoning about the components systematically;and (3) providing services to the components. this paper deals withthe last of these concerns. though our implementation uses Java, the fundamental ideas apply to any object-oriented language that supports messaging and threads. Alternative implementations use such languages coupled with object request brokers or remote procedure invocation mechanisms.
Workstation-based distributedcomputing environments are getting popular in both academic and commercial communities due to the continuing trend of decreasing cost/performance ratio and rapid development of networking...
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ISBN:
(纸本)0818675829
Workstation-based distributedcomputing environments are getting popular in both academic and commercial communities due to the continuing trend of decreasing cost/performance ratio and rapid development of networking technology. However, the work load on these workstations is usually much lower than their computing capacity, especially withthe ever-increasing computing power of new hardware. As a result, the resources of such workstations are often under-utilized and many of them are frequently idle. A preemptive process migration facility can be provided, in such a distributed system, to dynamically relocate running processes among the component machines. Such relocation can help cope with dynamic fluctuations in loads and service needs, improve the system's fault tolerance, meet real-time scheduling deadlines, or bring a process to a special device. this paper presents a process migration subsystem for tolerating process and node failures on a workstation based environment. the design and implementation of the subsystem are also discussed.
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