分布式存储环境下并行计算可扩展性的研究与应用

对本文的研究与创新工作概括如下 :( 1 )并行计算模型是研究并行计算可扩展性的基础。本文在深入分析已有并行计算模型的基础上 ,对常用并行计算模型进行分类 ,指出了它们的适用范围和优缺点。( 2 )深入分析了可扩展性与执行时间、可扩展性与单机性能之间的关系。结果表明 :如果片面强调执行时间或单机性能 ,可能会对可扩展性带来不利的影响。从理论和实验上分析了任务和数据分配策略对并行系统可扩展性的影响。( 3)首次从费用有效性的角度提出了近优可扩展模型。它不仅可以描述并行系统的可扩展能力 ,而且可以根据小规模系统的性能指标 ,预…     

一个支持开放分布式处理的DRPC模型*

开放分布式处理ODP(open distrlbuted processing)的目标是试图解决分布环境下软件的接口问题，以达到分布式系统的可移植性、透明性、互操作性．本文介绍了ODP要达到上述目标所需解决的一些关键性问题，分析了传统的远程过程调用模型的服务静态连接机制和其对ODP支持的局限性，并提出一个改进的、支持服务动态连接的远程过程调用模型，可以获得较好的性能．     

NOW——并行计算研究的一个新方向

工作站网络NOW(Network of Workstations),是指由若干工作站经网络连接而组成的计算机系统。近年来,随着工作站性能价格比的高速上升,计算机网络性能的不断改善,NOW越来越受到广泛重视,成为并行计算研究的一个引人注目的方向。 一、NOW的几个特点 1.NOW是一个基于高速通信网连接的工作站群集系     

并行FFT算法在3种并行计算模型上的设计和分析*

本文研究在APRAM，BSP和LogP等3种并行计算模型上并行FFT算法的设计和分析;分析这3种模型的内在特性及其相互关系;评价它们在设计和分析并行算法时的可用性和可操作性．     

工作站网络环境下的并行计算

当前工作站网络环境（ＮＯＷｓ）下高性能科学与工程计算是并行计算的一个热门话题，本文借助于ＬｏｇＰ并行计算模型，提出了一套新的效率评价准则，用于优化并行算法效率以达到最佳实现效果，揭示了影响算法并行效率发挥的关键因素，并从算法和程序设计角度提出了相应措施，探讨了急需解决的几个关键性问题，三个典型应用问题的数值实验结果文中给出。     

NOW环境下并行计算中的通信时延问题

1引言 工作站网络(NOW,Network Of Workstations)是一组专用或通用的计算机特别是性能工作站通过网络连成的计算机系统,由于NOW用于并行计算的主要资源是工作站,所以它被称为工作站群     

一种实现并行计算的新主充技术—NOW

当前，在并行计算领域，ＮＯＷ正受到日益重视，国外很多学者和厂商对这一技术进行着研究和开发，并预言它将具有与ＭＰＰ一样的地位，主导今后并行计算技术的发展，本文对ＮＯＷ进行介绍，回答关于ＮＯＷ的几个问题，分析实现ＮＯＷ的关键所在，并对其发展前景进行展望，试图引起国内同行对这一新技术的关注。     

分布式程序设计语言DC及其在松散耦合分布式环境中的实现

ＤＣ是一种支持分布式程序设计的编程语言，它是由Ｃ语言向上兼容扩充得到的．本文介绍ＤＣ及其在工作站网络环境下运行时支持系统的设计与实现，最后给出测试结果．     

分布式图形处理的研究与发展*

分布式图形就是在分布式系统上研究计算机图形的生成，是分布式系统与计算机图形学结合的产物．本文结合作者的研究工作对分布式图形中的研究内容(并行处理模型、支撑环境、分布式图形算法、分布式图形语言和图形库等)进行了概述；讨论了分布式图形在动画制作、科学计算可视化、多媒体和虚拟环境中的应用，在此基础上对分布式图形的发展进行了展望．     

并行程序的流程图分析法*

本文给出一种对Ada并行程序的流程图分析法．该方法不仅给出在并行程序中，并发多任务之间相互通信的一种可视化的表示，同时可检查出并行程序中存在的死锁，并能启发如何消除死锁．并行流程图在检查死锁的方便性、消除死锁的启发性、实际应用的可行性和对并行算法思想的描述性等方面明显优于已知的Petri网分析法。     

面向混合并行计算系统编程环境的研究与实现

分析了基于CMP节点的混合并行计算系统并行处理模式,基于分层次的自顶向下、逐步细化的思想,设计并实现了面向此类混合并行计算系统的编程环境,从而大大降低程了序设计人员在此类环境下编写并行应用程序的复杂度,减少了程序编码错误,提高了编程人员的效率。     

云计算环境下的容错并行Skyline查询算法研究

云计算为分布并行Skyline查询提供强大存储能力和计算能力的同时,其大规模数据中心固有的故障频发特性给可靠Skyline查询处理带来极大挑战。现有研究致力于提高Skyline算法的响应时间、渐进性、负载均衡等各项性能,不能保证故障情况下查询继续正确执行。为此,提出一种容错并行Skyline查询算法(fault-tolerant parallel Skyline,FTPS)。该算法通过故障监测和任务迁移,使得能够在查询过程中及时发现故障,并将故障节点的计算任务迁移到副本节点,保证查询的正确执行。理论分析和实验证明,FTPS算法能够在不影响正常Skyline查询处理性能的情况下获取较好的容错处理性能。     

Design and Implementation of a Practical Parallel Delaunay Algorithm

This paper describes the design and implementation of a practical parallel algorithm for Delaunay triangulation that works well on general distributions. Although there have been many theoretical parallel algorithms for the problem, and some implementations based on bucketing that work well for uniform distributions, there has been little work on implementations for general distributions. We use the well known reduction of 2D Delaunay triangulation to find the 3D convex hull of points on a paraboloid. Based on this reduction we developed a variant of the Edelsbrunner and Shi 3D convex hull algorithm, specialized for the case when the point set lies on a paraboloid. This simplification reduces the work required by the algorithm (number of operations) from O(n log ² n) to O(n log n) . The depth (parallel time) is O( log ³ n) on a CREW PRAM. The algorithm is simpler than previous O(n log n) work parallel algorithms leading to smaller constants. Initial experiments using a variety of distributions showed that our parallel algorithm was within a factor of 2 in work from the best sequential algorithm. Based on these promising results, the algorithm was implemented using C and an MPI-based toolkit. Compared with previous work, the resulting implementation achieves significantly better speedups over good sequential code, does not assume a uniform distribution of points, and is widely portable due to its use of MPI as a communication mechanism. Results are presented for the IBM SP2, Cray T3D, SGI Power Challenge, and DEC AlphaCluster. Received June 1, 1997; revised March 10, 1998.     

Parallel Computing on an Ethernet Cluster of Workstations: Opportunities and Constraints

Parallel computing on clusters of workstations is receiving much attention from the research community. Unfortunately, many aspects of parallel computing over this parallel computing engine is not very well understood. Some of these issues include the workstation architectures, the network protocols, the communication-to-computation ratio, the load balancing strategies, and the data partitioning schemes. The aim of this paper is to assess the strengths and limitations of a cluster of workstations by capturing the effects of the above issues. This has been achieved by evaluating the performance of this computing environment in the execution of a parallel ray tracing application through analytical modeling and extensive experimentation. We were successful in illustrating the effect of major factors on the performance and scalability of a cluster of workstations connected by an Ethernet network. Moreover, our analytical model was accurate enough to agree closely with the experimental results. Thus, we feel that such an investigation would be helpful in understanding the strengths and weaknesses of an Ethernet cluster of workstation in the execution of parallel applications.     

并行面向对象可视化程序设计环境的设计与实现

将可视化和面向对象技术引入并行程序设计将大大提高并行程序的开发效率，文章介绍了基于并行C＋＋的并行面向对象可视化开发环境的设计思想和组成结构。     

并行和分布式环境内核调试器的研究与设计

内核调试器在操作系统的设计和维护中是重要的。     

Tree-Based Parallel Algorithm Design

In this paper a systematic method for the design of efficient parallel algorithms for the dynamic evaluation of computation trees and/or expressions is presented. This method involves the use of uniform closure properties of certain classes of unary functions. Using this method, optimal parallel algorithms are given for many computation tree problems which are important in parallel algebraic and numerical computation, and parallel code generation on exclusive read and exclusive write parallel random access machines. Our algorithmic result is complemented by a P-complete tree problem. Received February 13, 1995; revised March 25, 1996.     

Quasidifferential Optimization Algorithms in a Parallel Computation Environment

In this paper some parallel algorithms for the minimization of a quasidifferentiable function in the sense of Dem'yanov are considered. In particular a new parallel method for the search of a descent direction of a subdifferentiable function is presented. Such a method is based on the approximation of the subdifferential by a simplex which is related to the directional derivatives of the function at the current point; the direction of descent is found by solving in parallel some quadratic programming problems on the simplex. Some ideas about the possibility of reducing the number of constraints are also presented. Based on this new method, an algorithm for quasidifferentiable functions is sketched.     

基于BSP的并行程序设计

BSP模型是独立于并行体系结构,即可作为并行计算模型又可作为并行程序设计模型。利用该模型进行并行程序设计简单、方便,而且可移植性强,可在多种并行系统上实现。     

基于PVM的启发式搜索的并行计算模型设计

通过分析人工智能中的A和A^*启发式搜索,提出了通过PVM工具包,设计和实现A和A^*启发式搜索的并行计算模型。在启发搜索过程中同时进行评估函数计算,使计算的速度加快。解决了在搜索解空间庞大,评估函数计算复杂的情况下,使用单计算机计算速度慢的问题。该文实现了基于PVM的启发式搜索过程,该模型可应用于一般性启发式搜索问题的并行计算模型。