面向分布式对象的一种集成服务报表系统

结合一个分布式网络下报表系统设计实例,提出了基于服务的分布式软件设计思想,采用将报表客户端以及报表服务包装成CORBA对象并通过数据服务与分布式数据源进行通信的方案。并就远程报表系统的设计与实现以及数据服务的具体问题进行了论述,给出了程序流程和设计要点。     

基于Agent的协同设计系统ABCD的研究与实现

提出了一种基于Agent的产品协同设计系统ABCD(Agent-BasedCooperativeDesign),分析了系统的体系结构并描述产品协同设计的过程。系统采用Java作为软总线,通过对一个复杂的机械产品设计实例,研究了协同设计的问题,给出了一种可行的解决方案,有效地解决了异构环境下产品分布式协同开发。     

集群环境下分布式索引的实现

针对分布式存储系统上使用非主键访问数据带来的性能问题,探讨在分布式存储系统上实现索引的相关关键技术。在充分分析分布式存储特征的基础上,提出了分布式索引设计和实现的关键点,并结合分布式存储系统的特点及相关的索引技术,讨论了索引的组织形式、索引的维护和数据一致性等问题;然后基于如上的分析,选择在分布式数据库系统OceanBase开源版本上,设计和实现分布式索引机制,并通过基准测试工具YCSB进行性能测试。实验结果表明,虽然辅助索引会对系统性能产生影响,但因为充分考虑了系统特征及存储特点,在不同数据规模下,该索引都能够将性能影响控制在5%以内。另外,使用冗余列的方式,能进一步将该索引的性能提升100%。     

面向模式的分布式软件构架可视化建模

主要阐述了面向模式的分布式软件构架的概念、原理和常用构架模式的特点。重点研究了提出的面向模式的软件构架建模语言、可视化建模工具的设计原理、功能及特点等,并以一个具体应用实例展示了该建模工具的实用性。     

分布式机载风电振动信号采集系统设计与应用

针对风电设备分布广泛、振动信号采集困难、监测数据处理要求高等特点,基于分布式风机在线监测的通用架构研发了一种能够安装于风机各关键部位的小型机载分布式风电状态监测装置,就系统设计中遇到的如硬件选型与架构设计、信号采样逻辑控制与处理、风机信号特征选择、上位机通信报文设计等关键问题进行了深入研究,并将该系统应用于实际风场的设备监测与故障诊断环境,验证了该装置的可靠性、有效性与可拓展性.     

基于组件的嵌入式软件开发中的几个关键问题

针对嵌入式系统的实际特性,着重从系统的角度提出构造一个嵌入式应用程序的开发架构,也可以称为开发框架.该开发架构是以基于组件的方法来开发嵌入式应用程序的,其主要研究系统结构规约、系统行为规约、组件配置和执行、程序产生和系统配置等几个关键问题.研究的结果将指导一个分布嵌入式应用程序开发框架的构造.     

A distributed and interactive system to integrated design and simulation for collaborative product development

The goal of applying collaborative product development in industry has raised the need to develop software tools supporting system integration and group collaboration. Current methods and tools mainly focus on the collaborative creation of design components and assemblies. However, few of them support the collaborative work in developing simulation models so that proposed design concepts and solutions can be evaluated by integrating expertise from several disciplines. The purpose of this research is to develop a distributed and interactive system on which designers and experts can work together to create, integrate and run simulations for engineering design. To develop such a system, a number of issues, e.g. effectiveness and efficiency of modeling work, the re-use of models, interaction and cooperation, accuracy of simulation, collaborative operation on models, etc., need to be addressed. This paper describes an open architecture to developing simulations for engineering design in a distributed and collaborative environment, identifies a set of key issues raised in this architecture, and presents the techniques employed in our solution.     

基于中间件的分布式电力监控系统设计与研究

提出了一种基于中间件、面向服务的分布式电力监控系统设计思路,论述了系统层次划分、关键节点抽象、服务设计等关键问题,讨论了数据服务和数据交换的原理与设计思路,并给出了工作流程。文章最后对系统界面远程可视化、系统合并以及时间同步等问题提出了解决方案。     

分布式仿真实验管理系统体系结构

针对采用分布式仿真进行体系对抗仿真面临的问题,如数据的一致性、实验资源部署、初始态势加载、仿真运行控制、实验数据回收等,设计分布式仿真实验管理系统体系结构。以满足武器装备论证对仿真实验样本数据需求为目标,辅助武器装备论证人员进行想定编辑、实验设置、实验规划、实验进程监控等,使分布式仿真技术更好地服务于武器装备论证。     

分布式网络安全管理系统的研究

网络的发展已经越来越趋向于大规模发展,分布式网络得到了广泛的应用,其信息安全成为当前网络安全的主要问题之一。本论文针对网络安全管理系统的应用现状,讨论了分布式网络安全管理系统的设计,从系统架构、安全策略以及安全构建技术三个角度给出了分布式网络安全管理系统的设计方案,对于进一步提高分布式网络安全管理系统的研究与应用水平具有一定借鉴意义。     

Distributed programming languages: design and implementation

Considerable discussion has appeared in recent literature about ‘distributed programming’. One area of discussion concerns the design of programming languages which support distributed algorithms. This paper examines the important issues in programming language design for distributed computing, and presents an example of a language philosophy which supports program development for a distributed environment. It also discusses experiences with the STARMOD distributed programming language.     

Design and analysis of a robust real-time engine control network

Increasing numbers of automotive control systems are being designed as distributed systems, with critical functions linked by electronic communications. This includes X-by-wire systems, which seek to replace mechanical or hydraulic linkages with electrical or communications links. These systems raise a number of new challenges: Safety is a function of the whole system rather than any one system feature. Thus, safety analysis and understanding must occur at the (complex) system level. A robust design process is essential to ensure that complex system issues and critical analysis occur at the right development stage and cover all appropriate parts of the system. This article provides a case study of a development project to show how these and other issues can be addressed. We describe the development of a communications network for a safety-related engine application that consists of a central electronic control unit (ECU) and a number of distributed actuators that are controlled via the network. We apply several techniques, such as hazard and scheduling analysis, to resolve safety and reliability issues     

网络爬行器的分布式设计

目前单机版的网络爬行器已无法在一个有效的时间范围内完成一次搜集整个Web的任务。该文采用分布式网络爬行器加以解决。在分布式设计中,主要考虑节点内部多个线程的并行和节点之间的分布式并行,包括分布式网络爬行器的策略选择和动态可配置性2个方面。实验结果显示站点散列法基本达到了分布式设计的目标,在追求负载平衡的同时将系统的通信和管理开销降到最低。     

Towards formal specification of a distributed computing system

Onboard spacecraft computing system is a case of a functionally distributed system that requires continuous interaction among the nodes to control the operations at different nodes. A simple and reliable protocol is desired for such an application. This paper discusses a formal approach to specify the computing system with respect to some important issues encountered in the design and development of a protocol for the onboard distributed system. The issues considered in this paper are concurrency, exclusiveness and sequencing relationships among the various processes at different nodes. A 6-tuple model is developed for the precise specification of the system. The model also enables us to check the consistency of specification and deadlock caused due to improper specification. An example is given to illustrate the use of the proposed methodology for a typical spacecraft configuration. Although the theory is motivated by a specific application the same may be applied to other distributed computing system such as those encountered in process control industries, power plant control and other similar environments.     

Correctness issues for distributed relational database design

This paper examines correctness issues that arise in distributed database design. A distributed relational database design is traditionally considered to be valid if every global relation can be reconstructed from its fragments by join operations. In this paper, three successively less restrictive definitions of validity are presented, each providing progressively improved handling of incomplete information. Examining these forms, a hybrid reconstruction approach involving inner- and outer-joins is proposed and we briefly describe its application to query formulation.We also propose replacing the notion of global reconstructability with the less restrictive, yet intuitively natural notion of object reconstructability. Universal relations need not be constructed. The need for maintenance of constraints across sites of a distributed system is discussed, and the notion of adistributed referential constraint is proposed which fulfills this need. Recommended by: Clement Yu     

Negotiation in a knowledge-based concurrent engineering design environment

Abstract: Computational support for concurrent engineering design presents a number of issues in the design of knowledge-based systems. A fundamental concern is the need to provide the life-cycle perspective in recommending design alternatives. It is argued that such a complex knowledge-based system should be distributed, due to the inherent problems with large knowledge bases and the maintenance of consistency. Inconsistent local views of a problem and different priorities on design issues are expected between different knowledge-based design perspectives. These inconsistencies and different priorities will lead inherently to conflict which has to be resolved. This paper addresses the issues and key variables in conflict resolution and presents a strategy that can be applied for managing the conflict resolution process. We propose negotiation as the method of analysing a conflict situation, applying an appropriate conflict resolution strategy and monitoring its performance. We present an overview of the nature of conflict and some conflict resolution strategies, and see in what situations certain strategies are appropriate.     

一个适合大规模集群并行计算的检查点系统

分布式检查点系统是大规模并行计算系统容错的重要手段．协议开销和检查点映像存储成为困扰并行检查点系统可伸缩性的两大瓶颈．针对并行应用程序的执行特征和高性能集群的体系结构特点,C系统分别采用动态虚连接技术和分布存储检查点映像的方法来有效降低协同式检查点的开销,增强检查点系统的可伸缩性．初步测试结果表明,C系统的设计策略适合大规模并行计算的容错．     

Implementation of a Unix network

A network of over 100 Unix computer systems has been established using the telephone system as its primary communications medium. The system is used primary for software exchange and remote mail, but permits processing with remote resources (files/programs). The authors faced a number of design issues common to distributed processing during its implementation. Several features of the system helped make it successful: low startup cost, no operating-system changes, easy user interface, locally administered security. This paper discusses the design issues and the authors' approach to the problems.     

DBSL: 一种面向入侵容忍的分布式入侵检测方法

面向入侵容忍的入侵检测是网络安全最前沿的研究热点之一,它是确保系统在威胁性的环境下提供预定服务的重要技术.容侵系统服务于复杂网络环境中,入侵往往在多个终端并发发生,传统入侵检测算法无法有效分析分布式入侵特征并且未对入侵后的系统恢复提供线索,不再适用.该文在研究分布式入侵特征的基础上,结合机器学习思想,提出了一种基于改进的分布式贝叶斯结构学习的入侵检测方法—DBSL方法.该方法特别适合于检测分布式入侵.文中对DBSL方法实现的关键问题进行了详细的讨论和分析.     

Design support systems: A case study of modular design of the set-top box from design knowledge externalization perspective

In this paper, the knowledge externalization of modular product design is introduced, which discovers and shares the design rules to increase the effectiveness/efficiency of the design process. This solution approach involves modeling modular products, formulating their design knowledge, and discovering implicit knowledge into design rules based on the rough set theory. The design rules are generated for improving heat dissipation issues of the set-top box (STB), which is perhaps the most attractive device for the home. A web based knowledge management of product design (KMPD) system is also implemented to provide adapted design rules and share design knowledge in distributed environment. The methodology discussed in the paper departs from the previous developments in design knowledge externalization as well as rough set theory application, thus creating a variable approach for product design.