基于移动Agent的分布式Web搜索模型的设计与实现

传统基于C/S模式的Web搜索方法对网络带宽和网络通畅性的要求都比较高,因此在当今互联网的海量数据中的检索效率比较低。在分析移动Agent技术特点的基础上,提出一种基于移动Agent的分布式Web搜索模型。该模型根据中文信息搜索的特殊性,将移动Agent技术与分类算法相结合,在搜索过程中引入了用户输入信息的预处理过程来进行信息分类,然后根据分类结果形成基于用户兴趣度的移动Agent搜索路径选择策略以及并发方法,由此来提高Web搜索的效率。详细介绍框架的组成和所采用的关键技术,并通过一个移动Agent的开发平台——Aglet平台对模型进行实现和实验。实验结果表明,采用该模型进行Web检索,比传统的C/S检索方式减少50%以上的搜索时间,而在各资源服务器存储的文件资源类别和资源数量差异较大情况下的搜索效率比非并发的其他移动Agent搜索模型搜索时间要减少70%以上。     

无线传感器网络的移动Agent机制研究

针对无线传感器网络中传统C/S计算模式存在的资源浪费、负载不均衡等缺陷,提出了一种基于移动Agent的无线传感器网络模型,并对移动Agent进行了详细设计。实验结果表明,在无线传感器网络环境中,移动Agent模式在网络耗能和延时方面都具有一定的优势。     

移动Agent在分布式数据访问中的应用

本文通过对移动Agent技术的研究,针对目前B/S模式下分布式数据访问存在的问题,结合网上科技论文查询系统,给出了一个基于移动Agent技术的分布式数据访问模型.     

基于Agent的客户机/服务器模型的设计与实现

在对Agent技术、多Agent技术以及Client/Agent/Server（客户机/代理/服务器）模式的理论分析基础上,指出了传统C/S结构的不足,提出了基于Agent的两层Agent/Server模式.然后基于该模式,给出了一个Agent/Server框架,简称ASFtame.由于引入了先进的FIPA标准和多Agent开发思想,ASFrame能充分发挥移动Agent的移动性,从而提高了应用系统的伸缩性和智能性.     

基于Mobile Agent的远程数据库访问模型

分析传统C/S计算模式应用于移动环境时产生的问题,针对移动应用的不同分类,构建相应基于Mobile Agent的远程数据库访问模型。讨论其原理和方法,给出实现算法,根据具体应用总结模型特点。实践结果表明,该模型可适应移动环境,正确性较高。     

面向移动Agent的软件度量工具的设计

利用软件度量工具对软件的各类质量属性度量,对于提高程序的质量有重要意义。在分析面向移动Agent的度量指标的基础上,设计并实现一种基于移动Agent的软件度量工具,该工具通过度量Agent与系统中其它Agent进行交互来获取度量所需信息并对其进行加工处理,用户可以通过度量Agent提供的接口查询度量的结果。最后给出度量指标与度量特征之间关系的实验结果。     

面向移动Agent的软件度量工具的设计

利用软件度量工具对软件的各类质量属性度量,对于提高程序的质量有重要意义.在分析面向移动Agent的度量指标的基础上,设计并实现一种基于移动Agent的软件度量工具,该工具通过度量Agent与系统中其它Agent进行交互来获取度量所需信息并对其进行加工处理,用户可以通过度量Agent提供的接口查询度量的结果.最后给出度量指标与度量特征之间关系的实验结果.     

基于移动Agent的分布式数据库的研究

本文对移动Agent技术进行了系统地概述和探讨,提出把移动Agent技术应用于分布式数据库系统中,并给出了在分布式数据库系统中利用移动Agent技术实现并发控制和分布式查询的方法。     

综合集成研讨厅的软件体系结构

主要研究基于网络的分布式综合集成研讨厅的软件体系结构.采用了一种扩展请求器-中介器-供应器的嵌套式客户/Agent/服务器计算模式;并利用该模式给出了一个基于Java的智能信息Agent构建的宏观经济决策研讨厅框架和工作机制;综合了Agent移动性与消息传递机制、算法与交互能力、多种类型Agent和多种设计模式.与通常的C/S与B/S模型相比,该系统具有更大的灵活性、更快的响应性能、对网络性能的低需求等特性.     

一种基于移动Agent的查询处理策略

介绍了移动Agent技术的特点，查询包含与归并的思想，并在此基础上提出了基于移动Agent的查询处理策略。通过合并查询减少了查询处理量；而使用移动Agent来处理查询请求与查询结果减少了网络通信量。     

构件化移动agent创建方法研究

分析了Client/Server中C/S结构与B/S结构,指出两种结构都不适用于移动agent。提出了一种构件化移动agent创建方法。采用程序变换技术,将移动agent体系结构分为本体体系结构和虚拟体系结构。本体体系结构表达移动agent实现特性,虚拟体系结构表达移动agent接口特性。最后,文章给出了一个移动agent体系结构,表明该文提出的创建方法在实践上确实可行、有效,较好地解决了上述结构的不足。     

An embeddable mobile agent platform supporting runtime code mobility,interaction and coordination of mobile agents and host systems

Agent technology is emerging as an important concept for the development of distributed complex systems. A number of mobile agent systems have been developed in the last decade. However, most of them were developed to support only Java mobile agents. In order to provide distributed applications with code mobility, this article presents a library, the Mobile-C library, that allows a mobile agent platform, Mobile-C, to be embeddable in an application to support mobile C/C++ codes carried by mobile agents. Mobile-C uses a C/C++ interpreter as its Agent Execution Engine (AEE). Through the Mobile-C library, Mobile-C can be embedded into an application to support mobile C/C++ codes carried by mobile agents. Using mobile C/C++ codes, it is easy to interface a variety of low-level hardware devices and legacy systems. Through the Mobile-C library, Mobile-C can run on heterogeneous platforms with various operating systems. The Mobile-C library has a small footprint to meet the stringent memory capacity for applications in mechatronic and embedded systems. The Mobile-C library contains different categories of Application Programming Interfaces (APIs) in both binary and agent spaces to facilitate the design of mobile agent based applications. In addition, a rich set of existing APIs for the C/C++ interpreter employed as the AEE allows an application to have complete information and control over the mobile C/C++ codes residing in Mobile-C. With the synchronization mechanism provided by the Mobile-C library for both binary and agent spaces, simultaneous processes across both spaces can be coordinated to get correct runtime order and avoid unexpected race condition. The study of performance comparisons indicates that Mobile-C is about two times faster than JADE in agent migration. The application of the Mobile-C library is illustrated by dynamic runtime control of a mobile robot’s behavior using mobile agents.     

基于移动Agent的信息搜索系统的研究

对传统客户/服务器模式的网络信息搜索系统的缺点进行了分析,将移动Agent技术引入信息搜索领域,阐述了Agent和移动Agent的概念,特点、开发工具,分析了其适合信息搜索的技术特点.提出了一个基于移动Agent的网络信息搜索原型系统(MAISS)来处理网络信息搜索,以实现搜索的高效率,低开销以及智能化,并时其结构及功能,实现机制和关键技术进行了深入的分析和讨论.     

移动代理在气田分布式计算机环境中的应用与研究

针对传统的基于DCOM/CORBA/EJB的C/S分布式计算机模型在网络的高速和可靠性中存在的矛盾,采用Aglet移动代理平台来构建气田生产运行监控管理系统的多级移动代理环境,并设计了基于移动代理的协作信息中间件(CISOM),以此来实现气田生产管理部门各级结点的信息交互和信息共享,使得气田生产运行监控管理系统具有良好的协作性、快速反应性、易重构性等特点,较好的满足了气田生产运行管理的需要.     

Rollover-free navigation for a mobile agent in an unstructured environment.

This paper introduces a navigation method for a teleoperated mobile agent (or robot) moving in an unstructured environment that includes unknown obstacles and uneven terrain, based on a guided-navigation algorithm (GNA) and a rollover-prevention algorithm (RPA). Although the mobile agent is primarily driven by an operator at a remote site, it reacts autonomously for avoiding collision with obstacles and for preventing rollover when it suspects/detects possible collision or rollover. The autonomous reactive motion is normally unexpected, thus there exists the inconsistency between the intended motion and the controlled motion of the agent from the operator. A force-reflection technique utilizing a force-feedback joystick is developed to manipulate this inconsistency. To verify the feasibility and effectiveness of the proposed navigation method, experiments with the Robot for Hazardous Application-Double Tracks (ROBHAZ-DT) (actual mobile agent) are successfully carried out.     

Mobile agent‐based computational steering for distributed applications

The mobile agent‐based computational steering (MACS) for distributed applications is presented in this article. In the MACS, a mobile agent platform, Mobile‐C, is embedded in a program through the Mobile‐C library to support C/C++ mobile agent code. Runtime replaceable algorithms of a program are represented as agent services in C/C++ source code and can be replaced with new ones through mobile agents. In the MACS, a mobile agent created and deployed by a user from the steering host migrates to computing hosts successively to replace algorithms of running programs that constitute a distributed application without the need of stopping the execution and recompiling the programs. The methodology of dynamic algorithm alteration in the MACS is described in detail with an example of matrix operation. The Mobile‐C library enables the integration of Mobile‐C into any C/C++ programs to carry out computational steering through mobile agents. The source code level execution of mobile agent code facilitates handling issues such as portability and secure execution of mobile agent code. In the MACS, the network load between the steering and computing hosts can be reduced, and the successive operations of a mobile agent on multiple computing hosts are not affected whether the steering host stays online or not. The employment of the middle‐level language C/C++ enables the MACS to accommodate the diversity of scientific and engineering fields to allow for runtime interaction and steering of distributed applications to match the dynamic requirements imposed by the user or the execution environment. An experiment is used to validate the feasibility of the MACS in real‐world mobile robot applications. The experiment replaces a mobile robot's behavioral algorithm with a mobile agent at runtime. Copyright © 2009 John Wiley & Sons, Ltd.     

无线传感器网络中基于数据融合的移动代理曲线动态路由算法研究

和传统的C/S模型相比,移动代理模型在数据融合方面更适合无线传感器网络.在基于移动代理的数据融合算法中,移动代理访问传感节点的顺序以及总数对算法的效率、网络寿命等有着重大影响.为此提出了一种基于数据融合的移动代理曲线动态路由算法设计方案.通过构造特定数据结构的数据报文和数据表,给出了目标节点基本信息收集算法获取目标节点到处理节点的最优路径;将移动代理路由归结为一个优化问题,由静态路由算法求出移动代理迁移的静态最优路由节点序列,进而获得了移动代理基于曲线的动态路由算法.理论分析和模拟实验表明,随着传感器网络规模的增大和传感数据量的增加,和其它算法相比,该算法有更小的网络耗能和延时.     

移动agent计算模式的无线传感器网络性能

无线传感器网络中使用的计算模式分为客户/服务器（Client/Server,C/S）计算模式和移动Agent（Mobile Agent,MA）计算模式。MA模式相比C/S模式具有的优点更适合无线传感器网络。本文通过理论分析和数学建模形式化MA数据处理与两种计算模式的性能指标。通过仿真比较了不同参数对这两种计算模式性能的影响。仿真结果表明,MA计算模式的网络性能受MA路由、MA处理代码大小、感知数据大小等多方面因素影响,在实际应用中需综合考虑以达到时延和能耗的均衡;而且MA模式具有良好的实时性,在一定条件下,其性能好于C/S模式。     

Distributed directory service and message routing for mobile agents

Research about networks and agents has identified the need for a layer that provides a uniform protocol to communicate with fixed and mobile agents. In order to preserve the compatibility with existing infrastructures, proposed solutions have involved a “home agent”, which forwards messages to a mobile entity. The mechanism of a home agent puts a burden on the infrastructure, which may hamper the scalability of the approach, in particular, in massively distributed systems, such as the amorphous computer or the ubiquitous/pervasive computing environment. Free from any compatibility constraint, we have designed an algorithm to route messages to mobile agents that does not require any fixed location. The algorithm has two different facets: a distributed directory service that maintains distributed information about the location of a mobile agent, and a message router that uses the directory service to deliver messages to a mobile agent. Two properties of the algorithm were established. Safety ensures that messages are delivered to the agent they were aimed at, whereas liveness guarantees that messages eventually get delivered. A mechanical proof of the properties was carried out using the proof assistant Coq.