包头市道路交叉口的交通改善及效果

通过对包头市主要道路交叉口的调查与分析,介绍了交叉口交通改善的措施,并对其效果进行了评价.     

A bivalency proof of the lower bound for uniform consensus

Bivalency argument is a widely-used technique that employs forward induction to show impossibility results and lower bounds related to consensus. However, for a synchronous distributed system of n processes with up to t potential and f actual crash failures, applying bivalency argument to prove the lower bound for reaching uniform consensus is still an open problem. In this paper, we address this problem by presenting a bivalency proof that the lower bound for reaching uniform consensus is (f+2)-rounds where 0?f?t−2.     

Specification Diagrams for Actor Systems

Specification diagrams (SD's) are a novel form of graphical notation for specifying open distributed object systems. The design goal is to define notation for specifying message-passing behavior that is expressive, intuitively understandable, and that has formal semantic underpinnings. The notation generalizes informal notations such as UML's Sequence Diagrams and broadens their applicability to later in the design cycle. Specification diagrams differ from existing actor and process algebra presentations in that they are not executable per se; instead, like logics, they are inherently more biased toward specification. In this paper we rigorously define the language syntax and semantics and give examples that show the expressiveness of the language, how properties of specifications may be asserted diagrammatically, and how it is possible to reason rigorously and modularly about specification diagrams.     

一种进程间异步通信模型的研究

该文给出了在分布式系统下一种基于消息传递与排队技术的进程间异步通信模型,并给出了消息队列的管理方法和消息传递模式,最后提出了用局部按名手址方式来解决进程寻址问题。     

Parallel implementation of the finite element method using compressed data structures

This paper presents a parallel implementation of the finite element method designed for coarse-grain distributed memory architectures. The MPI standard is used for message passing and tests are run on a PC cluster and on an SGI Altix 350. Compressed data structures are employed to store the coefficient matrix and obtain iterative solutions, based on Krylov methods, in a subdomain-by-subdomain approach. Two mesh partitioning schemes are compared: non-overlapping and overlapping. The pros and cons of these partitioning methods are discussed. Numerical examples of symmetric and non-symmetric problems in two and three dimensions are presented.     

瞿秋白等与"自由人"、"第三种人"的文艺论辩

20世纪30年代瞿秋白等与“自由人”、“第三种人”展开的论争,是国内文艺界马克思主义主流派与自由派关于文艺问题的第一次大规模争鸣。双方观点各有其价值和缺陷。这场论辩既有其积极意义,又带来负面影响,值得反思和总结。     

并行程序环境及其系统移植实现

并行程序设计环境作为分布并行系统中，并行应用程序开发设计与调试运行控制的工具，对于并行处理技术的研究发展与推广应用，具有重要的作用、本文将分析讨论并行程序环境Ｅｘｐｒｅｓｓ与ＰＶＭ的系统特点及其实现方法，同时，介绍Ｅｘｐｒｅｓｓ系统在并行图归约智能工作站上的系统移植实现。     

不确定性MPI／PVM程序的完全调试

讨论如何完全地调试不确定性MPI／PVM并行程序．在循环调试过程中,不确定性导致前次遇到的错误在以后的执行中很可能无法再现．基于MPI／PVM的FIFO通信模型,给出一种记录－重放技术的实现．通过可控制的重放,用户可以覆盖所有可能的程序执行路径,从而达到完全调试的目的．和其它方法相比,所提供的方法所需时空开销要小得多．此技术已在两种消息传递体系结构上得到实现：一种是曙光－2000超级服务器（由国家智能计算机研究中心开发）,它由单处理器（PowerPC）结点经MESH网互联而成;另一种是国家高性能计算中心（     

黄河小浪底水电站尾水岔管水力试验研究

通过模型试验研究，对小浪底水电站原尾水岔管体型进行了修改，减小水力损失，每年可多发千万ｋｗｈ电，年效益达百万余元．     

一个基于消息传递接口和面向对象的图像信号处理并行向量库

传统并行软件系统的设计和实现存在着开发效率低、质量难以保证和可移植性差等问题。针对这些问题,采用开发标准并行库的方法加以解决。借鉴高性能嵌入式计算软件计划(high performance embedded computing software initiative,HPEC_SI)的解决方法,基于消息传递接口(message passing interface,MPI)的消息传递机制,对图像/信号处理中的一些典型并行算法以类组件的方式进行封装,设计和实现了具有面向对象特征的、用于图像/信号处理的并行向量库,提供给应用软件开发人员一个良好的开发环境。通过测试和实验证明,该库可以高效地实现相应的向量矩阵并行算法,并具有简单易用、可复用性和可移植性强、效率高的特点。