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。     

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．     

基于Linux的Beowulf集群的实现

中国科学院等离子体物理研究所是国内从事核聚变研究和托卡马克(Tokamak)实验的主要基地,由于实验研究的需要,有必要建立自己的大型并行计算机系统,进行托卡马克实验的数值模拟等研究课题。文章介绍了在普通PC机上利用Linux操作系统实现基于分布存储结构的Beowul集群系统的方法,同时也介绍了基于消息传递模型(Message Passing Interface,MPI)的并行程序设计方法。     

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。     

整数阶复宗量变形贝塞尔函数的计算

根据整数阶复宗量变形贝塞尔函数模值随阶数n的变化趋势 ,给出了其数值计算的方法 .对于第一类和第二类变形贝塞尔函数分别采用向后递推和向前递推的算法 ,结果证明这种方法是快速且精确的 .     

Data flow analysis of distributed communicating processes

Data flow analysis is a technique essential to the compile-time optimization of computer programs, wherein facts relevant to program optimizations are discovered by the global propagation of facts obvious locally. This paper extends several known techniques for data flow analysis of sequential programs to the static analysis of distributed communicating processes. In particular, we present iterative algorithms for detecting unreachable program statements, and for determining the values of program expressions. The latter information can be used to place bounds on the size of variables and messages. Our main innovation is theevent spanning graph, which serves as a heuristic for ordering the nodes through which data flow information is propagated. We consider bothstatic communication, where all channel arguments are constants, and the more difficultdynamic communication, where channel arguments may be variables and channels may be passed as messages.A preliminary version of this paper appeared in the proceedings of the Sixth Annual ACM Symposium on Principles of Programming Languages, pp. 257–268, June 1979.Supported by National Science Foundation Grant NSF MCS82-00269 and the Office of Naval Research Contract N00014-80-C-0647.Supported by National Science Foundation Grants NSF DCR-8505873 and NSF CCR-8704309.     

关于安全案例论证构建的综述

安全案例提供清晰、全面和可靠的论据,说明系统在特定环境下的操作满足可接受的安全性.在受监管的安全攸关领域,如汽车、航空和核能等领域,认证机构通常要求系统经过严格的安全评估程序,以确保其符合一个或多个安全标准.在系统开发中应用安全案例是一种新兴的技术手段,以结构化和全面的方式表达安全攸关系统的安全属性.我们对安全案例的四个基本构建步骤—确定目标、收集证据、构建论证和评估安全案例—进行简要介绍.然后聚焦于构建论证这一关键步骤,详细介绍现有的8种安全案例表达形式,包括目标结构符号(GSN)、声明-论点-证据(CAE)、结构化安全案例元模型(SACM)等,并分析了它们的优缺点.由于安全案例所需材料的显著复杂性,软件工具通常被用作构建和评估安全案例的实用方法.我们比较7种用于安全案例开发和评估的工具,包括Astah System Safety、gsn2x、NOR-STA、Socrates、ASCE、D-Case Editor和AdvoCATE.此外,本文还深入探讨了安全案例构建中所面临的多重挑战,这些挑战包括数据的可靠性和完整性、复杂性和不确定性的管理、监管和标准的不一致、人因工程、技术的快速发展以及团队和跨学科合作6个方面.最后,我们展望安全案例的未来研究方向,揭示其潜在应用和研究问题.     

Development of quantitative reasoning and gender biases.

One hundred twenty-seven 7-, 9-, and 11-year-old children were presented large or small samples of own-gender enhancing or other-gender enhancing observations. Children read arguments based on the observations, rated argument intelligence, judged the number of other children to whom the observations could be generalized, and provided verbal justifications for their judgments. Own-gender reasoning biases declined with age; these declines were, however, partially accounted for by declines in the strength of self-reported gender affiliations. Reasoning biases-demonstrated by problem-to-problem shifts in reasoning quality-were constrained by sample size, indicating a modest degree of rationality even among 7-year-olds. Specifically, biases co-existed with reasonably extensive generalization from large samples of other-gender evidence. Children were thus able to satisfy motivations for own-gender favoritism and reason in accord with the law of large numbers. Several explanations of the findings-based on changes in the salience of gender, multiple classification skills, and the ability to reason independently from beliefs-are offered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

我国矿业走出去必要性分析—中国数据

我国矿产资源人均占有量极低,矿产资源产量迅速增长,但矿产资源基础储量明显下降,矿产资源开发强度过大,导致矿产资源可持续供应能力显著下降,我国矿产资源总体对外依存度呈扩大趋势。中国仍处于工业化发展的中后期,对矿产资源的需求仍然很大,不能只强调"立足国内",而不强调"走出去"。