【作者】 朱仁欢；

【导师】 蔡家楣；

【作者基本信息】 浙江工业大学 ， 计算机应用， 2004， 硕士

【摘要】 随着网络技术的迅速发展和不断渗透，随着诸如笔记本电脑、智能手机、PDA、智能手表等移动设备的快速增长，在任何时候、任何地点都能接入信息网获取所需的信息将成为21世纪新型人类的普遍需求，移动计算技术将使得这种需求得以实现。但移动计算有其自身的特点，开发移动应用时会遇到巨大的挑战。比如当这些设备在移动时不得不面对网络的短暂性连接或是不可预知的掉线情况；这些设备的资源通常是很有限的，电池容量很小、CPU速度很慢、内存很少；他们要求能适应位置、上下文条件、网络带宽改变等环境的变化，同时做出适当的反应。所有这些挑战，在传统的固网上是不存在或者说是无须考虑的，但是一旦在移动网络中开发应用，就不得不面对这些挑战。 为此人们提出使用中间件技术来支持移动计算应用。中间件是一种位于平台(硬件和操作系统)和应用之间的，独立的系统软件或服务程序，分布式应用软件借助这种软件在不同的技术之间共享资源。 本文先是比较了传统分布式系统中的中间件和移动分布式系统中的中间件的特征，提出了移动中间件的参考模型和系统特性，指出移动中间件可以解决移动计算面临的挑战。然后详细介绍了移动中间件，分析了现有移动中间件的研究状况，提出在本文中讨论一个面向消息的移动中间件系统。 消息中间件是基于消息传递或消息队列原理的一类中间件，现有的消息中间件不支持移动计算应用。本文讨论了支持移动计算应用的一种技术：面向消息的移动中间件技术，提出了一个基于发布／订阅模式的移动消息中间件MobileMOM的解决方案。 MobileMOM由下面三个主要功能模块组成：(1)MobileMOM Client，基于XMLBlaster的轻量级的移动消息中间件客户端；(2)Mobile UMS，移动统一消息系统，可以看作为连接客户端和服务端的消息Hub。它包含了多种为两者提供可靠有效传输的插件；(3)MobileMOM Server，一个基于XMLBlaster的服务端。 本文提出了移动消息中间件MobileMOM的设计框架，应用模式及部分实现与应用。更多还原

【Abstract】 Recent advances in wireless networking technologies and the growing success of mobile computing devices, such as laptop computers, smart phones, personal digital assistants, watches and the like, are enabling new classes of applications that present challenging problems to designers. Mobile devices face temporary loss network connectivity when move; they are likely to have scarce resources, such as low battery power, slow CPU speed and little memory; they are required to react to frequent and unannounced changes in the environment, such as high variability of network bandwidth, and in the resources availability. To support designers building mobile applications, research in the field of middleware system has proliferated. Middleware aims at facilitating communication and coordination of distributed components, concealing complexity raised by mobility from application engineers as much as possible. In this paper, we examine characteristics of mobile distributed systems designed and distinguish them from their fixed counterpart. We introduce a framework to support mobility, and we present a detailed comparative review of major results reached in this field.Message oriented middleware (MOM) is a specific class middleware that operates on the principles of message passing or message queuing. Existing MOM system doesn’t support the function for mobile computing environment. In the near future, requirements of mobile computing will increase and more dynamic services for mobile computing will be required. And integrating with wireless networks is becoming almost commonplace.This paper presents the study, design, and implementation of MobileMOM, a message oriented middleware system for mobile computing. It provides a solution for mobile application specific problems such as resource constraints, networkcharacteristics, and data optimization. MobileMOM consists of three main functions:1-MobileMOM Client, a lightweight client of Message Oriented Middleware(MOM) based on XMLBlaster;2-MobileUMS, for reliable and efficient transmission between mobile devices and a server with pluggable components; 3-MobileMOM Server, a MOM server based on XMLBlaster Server.更多还原