【作者】 吴延卯；

【导师】 郭庆平；

【作者基本信息】 武汉理工大学 ， 计算机应用技术， 2006， 硕士

【摘要】 随着互联网技术的发展,如何在分布式环境下建立高效、安全和健壮的应用系统,成为当前的研究热点之一。分布式计算结构经历了终端/主机结构、以文件服务器为中心的网络结构、客户机/服务器结构、浏览器/服务器结构和基于Internet/Intranet的多层结构,近年来,移动Agent技术被认为是一种易于设计、实现和维护的Intemet/Intranet环境下分布式系统的新兴技术,并成为学术界企业界研究的热点。 移动Agent是具有移动特征的Agent,它可以自主的从网络中一台机器移动到另一台机器,代表用户完成指定的任务。移动Agent技术涉及到计算机网络、分布式系统和人工智能等多种领域,由于其移动性、自主性和协调性等特点,已经在Internet环境中的分布式系统中得到了应用,并显示出巨大的应用前景和优越性。 本文旨在探索移动Agent技术在构建分布式信息系统中的应用,研究采用移动Agent技术进行软件开发所遇到的问题及解决方案,在研究移动Agent技术的基本理论和应用特点的基础上,分析了基于移动Agent技术的软件设计方法,提出了利用移动Agent技术构造Internet环境下的分布式数据库信息搜索系统的方案。本文首先阐述了软件Agent的概念,对移动Agent的体系结构、关键技术、技术优势和安全性方面作了完整的介绍,介绍了基于移动Agent的信息服务模型,并在此基础上提出了一个分布式数据库检索信息系统的模型,分析了各个子系统的构成及其相互关系;围绕移动Agent的特点,考虑到系统出现故障时的容错性和稳定性,设计了解决移动Agent迁移失效的船坞系统和解决移动Agent通信失效的通信管理系统,为用户和信息源提供了一个值得信赖的安全机制。文章着重介绍了移动Agent开发平台Aglet及其编程机制,论述了Aglet中的事件委托模型和消息机制,为正确程序设计提供了关键支持,并以Aglets为开发平台并结合其他技术,实现了这一模型,并在Linux、Windows操作系统和MySql、SqlServer数据库系统上对其进行了测试。最后分析了用移动Agent技术开发分布式系统的优势与不足。更多还原

【Abstract】 Along with the development of Internet technology, how to establish highly effective, safe and the vigorous application system under the distributed environment has become one of current research hot points. The distributed computing infrastructure has experienced the terminal/mainframe architecture, file server centered network architecture, the C/S architecture, the B/S architecture and the multilayer architecture based on Internet/Intranet, In recent years, Mobile Agent technology is considered to be an easily to design, realize and maintained new technology under Internet/Intranet environment, and becomes the research hot point in academic and business communities.Mobile Agent has the motion characteristic. It is independent of machine and can move from one machine to another, and completes the task on behalf of the user. Mobile Agent technology involves the computer network, the distributional system, the artificial intelligence and many other kinds of domains. Because the characteristic of mobility, independency and coordination, it has already applied in the Internet environment, and demonstrated huge prospect and superiority.The main purpose of this thesis is to explore concrete application of mobile agent technology to construct distributed system and study some problems and their solutions when we apply mobile agent technology in software development. The software development method based on mobile agent was analyzed in detail after having studied the basic concepts and application characteristics of mobile agent. Then a distributed multi-database retrieval information system model was proposed. This thesis elaborates the software agent concept, and gives an integrity introduction to essential techniques, the technical superiority and security of mobile agent’s structure. Then it describes an information service model based on mobile agent, and proposes a distributed multi-database retrieval information system model based on this foundation. The subsystem’s constructions and their reciprocity have been analyzed;an agent dock system to solve agent migration expiration and a communicationmanagement system to solve the correspondence expiration have been designed, so that it has provided a safety mechanism for users and information sources. The thesis explores in detail the mobile agent soft development kit Aglet and its programming mechanism, elaborates the Aglet event model and the message transmit mechanism, which provide key support for the correct programming. Using Aglet as development platform and unifying other technologies, we have implemented this model, and tested it on the Linux networking environment, the Windows operating system and the MySql, SqlServer database system. At last the superiority and insufficiency using mobile agent technology to develop a distributed system have been discussed.更多还原