语义转换--直接指称语义到接续指称语义

指称语义分为直接指称语义和接续指称语义，其中后一种语义描述的难度较大，给出了直接指称语义描述到接续指称语义描述的转换方法，这就使得这种语义转换的自动化成为可能．转换算法揭示了直接指称语义与接续指称语义之间的内在关系，同时也提供了写接续指称语义描述的有效方法．当需要检验同一种语言的直接指称语义描述和接续指称语义描述是否等价时，提供的技术是很有用的。     

基于关系／网状的语义超图多媒体描述模型

本文提出了基于关系／网状的语义超图功述模型及各操作，引和面向对象的方法，统一描述对象和元组，提出了对象间的语义联系，基于联系的各种操作和施加工对象的方法机制。在语义超图层次，描述和操作了不同语义类的对象；在语义子图层次，描述了每一语义类的对象间的多对多关系及其操作，因此，该模型可用于描述和处理工程领域中的不同语义类多对多关系的复杂多媒体对象。     

对象描述语言及其指称描述

在面向对象的软件构造中，对象被视为软件系统的基本构件．本文提出对象规范描述语言ＯＤＬ（ｏｂｊｅｃｔｄｅｓｃｒｉｐｔｉｏｎｌａｎｇｕａｇｅ），并给出其主要结构的ＳＯＰ指称描述．ＳＯＰ演算的理论范集给出对象的形式描述．ＳＯＰ理论范集反映了对象的封装性，在这样的逻辑框架下，对象的属性（结构）和动作（行为）得以统一．对象聚合提供了由已有对象描述构造复杂对象描述的机制；而继承则可以扩充给定的对象描述并保持原描述的特性．此外，本文还区分了继承和子类这２个相似而又不尽相同的概念.     

接续到直接的指称语义转换

接续和直接指称语义之间的转换的主要难点在于不保函数基调．基于Monad思想推导出的接续语义函数和直接语义函数之间的关系，给出了基于规约的从接续指称语义描述形式到直接指称语义描述形式的转换技术，分别考虑了接续函数在不同情形下的处理．最后给出了转换算法的Haskell实现系统，验证了转换的可行性．     

面向语义集成--本体在Web信息集成中的研究进展

本体（Ontology）是描述概念及概念之间关系的概念模型，通过概念之间的关系来描述概念的语义，作为一种有效表现概念层次结构和语义的模型，本体在Web信息集成中得到广泛的应用，文中就目前本体在Web信息集成中的应用做了分析与探讨，以期对相关领域的同行有参考作用。     

语义Web及层次结构

本文描述了下一代万维网－语义Web及其基本内容，文中介绍了语义Web的定义及其层次结构，描述了支持语义Web各层的基本技术和RDF（资源描述框架）／RDF模式语言OIE（本体推理层），逻辑层及有关技术等，并描述了语义Web的发展前景。     

面向服务的语义网格框架及其关键技术

由于传统的网格存在信息格式异构等问题，导致网格无法像原先设想的那般高效无缝自动化，因此在网格中引入语义的概念，希望通过语义网格来弥补这种缺陷。分析了语义网格与网格及语义Web的关系，阐述了语义网格中与语义web共享的关键技术，并基于面向服务的思想，提出了一个面向服务的语义网格框架，并对它做了详细的描述。     

语义Web中的本体推理研究

从语义Web的基本概念开始，介绍了语义Web的层次结构；介绍了本体的基本概念以及用于本体描述的几种语言。用W3C推荐的本体描述语言OWL描述了一个本体实例，通过此实例对本体推理在本体建立中的冲突消解、描述优化、本体的合并和实例归类中的应用进行了研究，说明了本体推理在本体建立及本体应用中的作用。本体技术是语义Web的核心技术，所以建立和维护本体是语义Web中的主要工作之一，而基于本体的推理可以帮助建立和维护本体。     

基于LTS的Statecharts操作语义研究

Statecharts是一种用于复杂反应式系统行为的可视化规格语言。该文提出了一种基于标签变迁系统(LTS)的Statecharts操作语义描述方法，介绍了Statecharts及其项语法和一步语义，并基于进程代数描述Statecharts的并发行为，使用结构化的操作语义SOS规则描述Statecharts的组合语义，从而得到相应的LTS。     

OWL DL的形式化基础研究

W3C正在制定的OWL DL是一种面向语义Web的知识表示标记语言，具有较强的知识表达能力并适合大规模应用的推理效率，是语义Web领域对适合语义Web应用的知识表示标记语言进行研究的最新综合．在知识表示领域，为了对知识表达能力和推理效率做合适的折衷，进行了大量关于描述逻辑的研究，本文以描述逻辑作为OWL DL的形式化基础，详细分析了OWL DL和描述逻辑间的对应关系，用描述逻辑的语义解释了OWL DL的各个基本元素，从而可以将描述逻辑领域研究的大量成果应用到OWL DL上来，为进一步研究OWL DL的知识表示、推理等问题奠定了基础．     

Distributed BACI: a toolkit for distributed applications

We have built a distributed Ben‐Ari Concurrent Interpreter (distributed BACI), which provides easy‐to‐use commands to implement distributed algorithms. In distributed BACI, a send process, receive process, and interpreter process combine to provide the distributed system functionality necessary to implement distributed algorithms. In this paper, we introduce the distributed BACI toolkit, illustrate the toolkit with a distributed mutual exclusion algorithm, and discuss how the toolkit is implemented. Copyright © 2000 John Wiley & Sons, Ltd.     

Distributed database systems: where are we now?

The authors explain what is meant by a distributed database system and discuss its characteristics. They survey the state of distributed database technology, focusing on how well products meet the goals of transparent management of distributed and replicated data, reliability through distributed transactions, better performance, and easier, more economical system expansion. They then consider unsolved problems with regard to network scaling, distribution design, distributed query processing, distributed transaction processing, integration with distributed operating systems, and distributed multidatabase systems     

Optimization of steel structures using distributed simulated annealing algorithm on a cluster of personal computers

This paper presents a distributed simulated annealing (SA) algorithm for optimal structural design of steel structures under stress, maximum displacement, and inter-story drift constraints. To effectively harness the distributed computing capabilities of a cluster of PCs, a two-phased SA algorithm consisting of simulated quenching (SQ) and SA is developed and used for development of the distributed algorithm. The distributed algorithm is based on two different levels of parallelism, design variable level for a distributed SQ algorithm and candidate design level for a distributed SA algorithm. The distributed SA algorithm is applied to the discrete minimum weight design of a verifying example and two steel braced frame structures. The results show that the distributed SA algorithm implemented on a network of PCs can reduce the computational requirement significantly, and yield more stable convergence histories.     

集群分布式安全探讨

集群越来越多地暴露给来自公网的攻击者,有效灵活地安全管理机制成为现今集群的本质需求.本文分析集群面临的威协与挑战,从分布式认证、分布式访问控制、分布式监测、分布式安全通信等方面给出了分布式服务的结构性方法,介绍了现存分布式安全基础设施和一个集群安全监测工具中的分布安全机制.     

分布式车间调度优化算法研究综述

在分布式制造环境下, 分布式车间调度着重研究工件在工厂间的合理分配以及各工厂内的合理加工顺序, 以实现调度指标的最优化. 分布式车间调度的研究具有重要的学术意义和应用价值, 已成为生产调度领域的热点. 对 此, 围绕分布式并行机调度、分布式流水线调度、分布式作业车间调度、分布式装配调度和分布式柔性车间调度等问题, 重点综述分布式调度优化算法方面的代表性成果, 介绍分布式调度的若干应用, 最后指出有待于进一步研究的若干方向和内容.

     

分布式OSGi研究与发展*

OSGi分布式扩展技术将分布式计算技术与OSGi框架融合,使之能够支持跨多虚拟机的异构分布式处理,是OSGi领域的研究热点。系统地介绍了这一崭新领域的理论研究情况,分类比较了几种主流分布式扩展技术的异同,探讨了分布式扩展的性能以及应用进展情况,给出了未来研究与发展的趋势。     

Hierarchical distributed genetic algorithms

Genetic algorithm behavior is determined by the exploration/exploitation balance kept throughout the run. When this balance is disproportionate, the premature convergence problem will probably appear, causing a drop in the genetic algorithm's efficacy. One approach presented for dealing with this problem is the distributed genetic algorithm model. Its basic idea is to keep, in parallel, several subpopulations that are processed by genetic algorithms, with each one being independent from the others. Furthermore, a migration operator produces a chromosome exchange between the subpopulations. Making distinctions between the subpopulations of a distributed genetic algorithm by applying genetic algorithms with different configurations, we obtain the so-called heterogeneous distributed genetic algorithms. In this paper, we present a hierarchical model of distributed genetic algorithms in which a higher level distributed genetic algorithm joins different simple distributed genetic algorithms. Furthermore, with the union of the hierarchical structure presented and the idea of the heterogeneous distributed genetic algorithms, we propose a type of heterogeneous hierarchical distributed genetic algorithms, the hierarchical gradual distributed genetic algorithms. Experimental results show that the proposals consistently outperform equivalent sequential genetic algorithms and simple distributed genetic algorithms. ©1999 John Wiley & Sons, Inc.     

Protocols useful on the Internet from distributed signature schemes

Distributed cryptography deals with scenarios where a cryptographic operation is performed by a collective of persons. In a distributed signature scheme, a group of players share some secret information in such a way that only authorized subsets of players can compute valid signatures. We propose methods to construct some computationally secure protocols from distributed signature schemes, namely, we construct metering schemes from distributed noninteractive signature schemes. We also show that distributed deterministic signature schemes can be used to design distributed key distribution schemes. In particular, we construct the first metering and distributed key distribution schemes based on the RSA primitive.     

基于分布对象的同步回调模型的研究与实现

分布对象技术是分布异构环境下软件开发和系统集成的良好解决方案,然而在高性能分布计算领域,传统调用模型在异步特性方面的不足限制了分布对象技术在该领域的应用。因此,本文介绍一种新的基于分布对象的异步回调模型。测试表明,该模型能够有效改善分布对象系统的性能。     

Algorithms for Distributed Constraint Satisfaction: A Review

When multiple agents are in a shared environment, there usually exist constraints among the possible actions of these agents. A distributed constraint satisfaction problem (distributed CSP) is a problem to find a consistent combination of actions that satisfies these inter-agent constraints. Various application problems in multi-agent systems can be formalized as distributed CSPs. This paper gives an overview of the existing research on distributed CSPs. First, we briefly describe the problem formalization and algorithms of normal, centralized CSPs. Then, we show the problem formalization and several MAS application problems of distributed CSPs. Furthermore, we describe a series of algorithms for solving distributed CSPs, i.e., the asynchronous backtracking, the asynchronous weak-commitment search, the distributed breakout, and distributed consistency algorithms. Finally, we show two extensions of the basic problem formalization of distributed CSPs, i.e., handling multiple local variables, and dealing with over-constrained problems.