Design and Implementation of a Hybrid Agent Platform

This paper presents IMAP, a hybrid agent platform composed of several cooperating intelligent agents and mobile agents. IMAP is implemented in Java and Prolog. Java is used to implement the framework of the system, and in particular for supporting the communication between agents and mobility of agent, while Prolog is used to implement both adduction and derivation mechanisms. IMAP intends to independently employ the underlying derivation/adduction and mobility mechanism. In IMAP, intelligent agent and mobile agent can not only fully exploit individual virtue, but also cooperate to perform a task under a uniform platform. Intelligent agents in IMAP are equipped with hypothetical reasoning capabilities, performed by means of adduction: if the knowledge available to an agent is insufficient to solve a query, the agent could adduce new hypotheses. Each intelligent agent can accept queries from mobile agents by means of the interface module, each query is passed to the reasoning module of intelligent agent which performs a derivation and adduction in order to get an answer for mobile agent. IMAP also provides mobile agents a flexible and efficient coordination mechanism and a reliable migration mechanism, and supports persistence of agent state and agent security. Mobile agent's coordination mechanism exploits the advantages of the XML language and Linda-like coordination. This programmable Linda-like coordination mechanism suits the mobility and openness of the Internet application, XML standard for Internet data representation may guarantee a high-degree of interoperability between heterogeneous environments. The design and implementation key technologies of IMAP are described in this paper. An Internet based auction application example shows the suitability and the effectiveness of the IMAP, and its performance evaluation is also made. Finally, some conclusions and remarks are given.     

Coordinating Mobile Agents by the XML-Based Tuple Space

This paper presents Xspace,a programmable coordination paradigm for Internet applications based on mobile agents.The Xspace system fully exploits the advantages of the XML language and Linda-like coordination.It supports XML documents as tuple fields and multiple matching routines implementing different relations among XML documents,including those given by XML query languages,The Xspace uses Java as the implementation language;it is based on object-oriented XMLized tuple spaces to implement a portable and programmable coordination paradigm for mobile agents.The dsign and implementation procedures of Xspace are described in this paper,Experiment and performance evaluation are also made.Finally,some conclusinos and remarks are given.     

Xml dataspaces for the coordination of internet agents

This article presents MARS-X, a programmable coordination architecture for autonomous and mobile Internet agents. In MARS-X, mobile Internet agents coordinate through programmable XML dataspaces, accessed by agents in a Linda-like fashion. Therefore, MARS-X enforces open and uncoupled interactions and, via XML, it offers a high degree of standard interoperability. These properties suit very well the characteristics of both mobile Internet agents and the Internet environment itself. In addition, coordination in MARS-X is made more flexible and secure by the capability of programming the behavior of the XML dataspaces by reaction to the agents' accesses. An application example related to the management of on-line academic courses shows the suitability and effectiveness of the MARS-X architecture.     

MARS: a programmable coordination architecture for mobile agents

Mobile agents offer much promise, but agent mobility and Internet openness make coordination more difficult. Mobile Agent Reactive Spaces (MARS), a Linda-like coordination architecture with programming features, can handle a heterogeneous network while still allowing simple and flexible application design     

Engineering mobile agent applications via context-dependent coordination

The design and development of Internet applications requiring dynamic and possibly mobile access to Internet resources can take advantage of an approach based on autonomous mobile agents. However, mobility introduces peculiar issues related to the modeling and management of the agents' coordination activities. This paper introduces context-dependent coordination as a framework for the design and development of Internet applications based on mobile agents, and shows how it can be supported by a proper coordination infrastructure. Context-dependent coordination is centered on the notion of programmable coordination media, as the software abstraction via which an agent in an Internet site can access to local resources and coordinate with local agents. Programmability stems from the fact that the behavior of the media can be fully configured to influence agents' coordination activities. This enables local administrators to configure coordination media so as to enact site-dependent coordination policies, and mobile agents to configure the accessed coordination media to obtain an application-dependent behavior of the media themselves. Several application examples shows that exploiting context-dependent coordination promotes a clear separation of concerns in design and development, and can make applications more modular and easier to be maintained. The MARS system is assumed as an exemplar coordination infrastructure to clarify the concepts expressed and to show their actual implementation.     

基于共享空间的移动Agent交互

在移动agent应用环境中,agent并不是孤立地完成任务,它需要经常与其它agent交互并不断地与环境交互。而基于TupleSpace的交互模型已经被证明是最适合于移动agent环境的。该文将基于TupleSpace的交互模型进行智能性扩展,使其不仅具有反应力而且具有推理和学习能力,并将该模型作为移动agent系统中的交互媒体,支持移动agent之间、agent与系统资源间的交互。实际上,该模型松散耦合到移动agent环境,因而不仅支持交互,它还支持任何异质环境中(包括移动agent系统)的安全问题、效率问题及灵活性问题的解决。     

基于移动Agent技术的虚拟企业协调机制

虚拟企业由于需要具备对市场机遇的快速反应能力以及企业间的协作能力,必然需要与信息技术紧密联合,同时对系统架构的柔性和可扩展性提出了很高的要求。提出了一种基于移动Agent技术的虚拟企业协调机制,并通过基于XML的工作流技术保证了业务流程的灵活性和可扩展性,给出了使用Java反射机制的工作流引擎的实现机制。并进一步通过结盟、变更移动A-gent和监控移动Agent的具体实现,介绍了该机制下工作流的应用以及在Aglet移动开发环境下主从模式的开发。     

Coordination for Internet Application Development

The adoption of a powerful and expressive coordination model represents a key-point for the effective design and development of Internet applications. In this paper, we present the TuCSoN coordination model for Internet applications based on network-aware and mobile agents, and show how the adoption of TuCSoN can positively benefit the design and development of such applications, firstly in general terms, then via a TuCSoN-coordinated sample application. This is achieved by providing for an Internet interaction space made up of a multiplicity of independently programmable communication abstractions, called tuple centres, whose behaviour can be defined so as to embody the laws of coordination.     

基于移动代理的复杂电子化服务匹配系统

通过分析Internet环境下分布计算系统的特征，探讨了大规模、复杂电子化服务系统实现中所面临的难点。提出以移动代理机制和XML技术构建整个系统中最主要的匹配子系统。在使整个系统具有高自主性和松耦合的同时，又能确保服务匹配和执行的高效性和准确性。     

AgletBlackboard：Aglets系统协同机制的扩充

随着Internet的不断发展，移动Agent技术的应用越来越广泛。实际的应用通常需要由多个移动Agent共同来完成任务，如何组织与协调移动Agent之间的行动带来了对分布式环境中移动Agent之间协同的研究。本文介绍了移动Agent的四种协同模式，并针对Aglets系统中Aglet之间通过直接协同存在的不足．设计实现了基于黑板协同模式的AgletBlackboard，进一步提高了Aglets系统的功能。     

SecSpaces: a Data-driven Coordination Model for Environments Open to Untrusted Agent

In this paper we initiate an investigation about security problems which occur when exploiting a Linda-like data driven coordination model in an open environment. In this scenario, there is no guarantee that all the agents accessing the shared tuple space are trusted. Starting from the analysis of the few proposals already available in the literature, we present a novel coordination model which provides mechanisms to manage tuple access control. The first mechanism supports logical partitions of the shared repository: in this way we can restrict the access to tuples inside a partition, simply by limiting the access to the partition itself. The second mechanism consists of adding to the tuples some extra information which exploit asymmetric cryptography in order, e.g., to authenticate the producer of a tuple or to identify its reader/consumer. Finally, we support the possibility to define access control policies based on the kind of operations an agent performs on a tuple, thus discriminating between (destructive) input and (non-destructive) read operations.     

一种基于SOAP的移动Agent通信机制实现

SOAP（Simple Object Access Protocol,简单对象访问协议）技术有助于实现大量异构程序和平台之间的通信,从而使存在的应用能够被广泛的用户所访问。SOAP是把成熟的基于HTTP的WEB技术与XML的灵活性和可扩展性组合在一起。该文在分析已有的移动Agent通信机制上,结合XML,SOAP,Web Service等技术,提出了一种基于SOAP协议的移动Agent通信机制。     

基于SGML/XML的Internet信息发布

随着Internet技术的发展与应用的深入,特别是电子商务等深层次应用的迅速崛起,结构化地组织Internet上的信息,保持信息本身的结构与语义变得越来越重要.文章首先给出一种基于SGML／XML进行结构化信息组织与Internet信息发布的模型,并重点讨论了实现该模型的两个关键问题：SGML／XML信息的获取与信息的Internet发布.文中讨论的模型与关键问题对基于XML的应用系统具有很好的参考价值.     

The mobile groups approach for the coordination of mobile agents

We present the concept of mobile groups as a basic mechanism for the reliable coordination of mobile agents. Analogously to traditional group systems, mobile groups also provide message delivery guarantees and virtual synchrony. Furthermore, they make agent mobility not only visible for the group, but also consistently ordered with other group actions (such as crashes, joins, leaves, and other migrations). The mobile groups approach represents a novel mobility support mechanism, which can be used to handle reliability of mobile agents required at both, the application and system level (e.g., for coordinating distributed agents and for reliable agent migration, respectively). In this paper, we discuss the motivations for the mobile groups approach, formally define their properties, and present a membership protocol for such groups. We also discuss some implementation issues and related performance data, and present the advantages of mobile groups against mechanisms commonly employed for the coordination of mobile agents.     

面向对象的XML Bricks研究

XML Bricks作为新型XML文档的应用，已贯穿于Internet应用的许多领域之中．对XML Bricks这种新型的文档的应用进行分析，发现目前对XML Bricks的使用仅是一种简单的包含关系．通过对XML Schema的扩展，使XML Bricks具有面向对象的某些特性．如：多继承，阻塞，重载等功能．使XML文档定义具有更多的面向对象编程技术方面的功能，并且路出相应的表示符号和公式用来描述面向对象的XML Bricks，更好的实现了XML Bricks的复制机制．减少系统中的代码重复，使之具有较好的模块性和可移植性．     

Web服务、移动Agent及工作流技术在组建动态联盟中的应用

动态联盟的目标是可重构、软件重用和规模可变。基于XML的Web Service(WS)技术，由于其平台中性、松散耦合以及智能的服务发现机制成为企业间应用集成有效解决方案，同时将企业现有应用以Web服务形式包装可以更好支持实现动态联盟的三个目标。鉴于此，以WS技术为基础，结合工作流和移动Agent技术，从理论上提出组建动态联盟系统框架的方案。     

一种基于XML的数字水印技术

随着互联网技术的快速发展,由于XML具有使用灵活、开放、基于标准格式的互用性等特点,其应用面不断扩大.本文结合XML的结构、特点和实例,提出了把隐藏信息作为数字水印嵌入到XML文档的一种方案,该方案对在XML文档中实现信息隐藏具有一定的实际意义.     

基于XML/Web服务的分布式电子商务系统的研究

传统分布式计算技术CORBA,DCOM和RMI不适合于在松散耦合、异构的、有防火墙的Internet网络环境下进行电子商务应用系统的设计开发,而基于XML/Web服务的分布式电子商务系统则满足了远程的数据交互、异构平台上不同应用间相互通讯以及穿越防火墙等一系列复杂的功能需求。文中主要针对电子商务系统结构、异构数据集成、公共数据格式等几个关键性问题进行了深入的研究,从而解决在Internet/Intranet环境下构建基于XML/Web服务的跨平台的分布式电子商务应用系统中所存在的问题。     

移动代理技术模型的研究和实现

随着Ｉｎｔｅｒｎｅｔ的迅速发展,Ｉｎｔｅｒｎｅｔ上的软件Ａｇｅｎｔ将提供多种智能化的信息服务手段,文章主要讨论移动代理技术模型结构,实现的技术和方法,最后给出了一个作者开发的实际应用系统模型。