【作者】 李佳桐；

【导师】 张秀国；

【作者基本信息】 大连海事大学 ， 计算机科学与技术， 2012， 硕士

【摘要】 随着计算机技术和互联网技术的发展,面向服务的体系结构(Service-Oriented Architecture, SOA)逐渐成为一种新的分布式应用程序体系结构,Web服务及其组合作为SOA的实现手段之一受到了广大厂商、组织及研究学者的关注。特别是随着传感技术的发展,地球上的万事万物变得可感知和互联互通,上下文感知的Web服务组合能够实时感知用户所处的上下文及其变化,并据此调整系统自身行为,前摄地为用户提供服务和计算资源,从而减少人机交互,改善用户体验,提高服务针对性。然而,由于Internet的环境是动态、开放、多变、难控的,静态的Web服务组合已远远不能满足人们的需求。瞬息万变的商业环境也要求企业的IT系统能够迅速适应市场需求的变化,具有动态演化的能力。面对这样的环境,将上下文感知与动态演化技术相结合,研究上下文感知的Web服务组合动态演化模型与方法具有深远的意义。本文在分析总结国内外主流动态演化框架的基础上,对Web服务组合、BPEL、上下文感知、进程代数、动态演化等理论和技术进行了深入地学习和研究,给出了上下文感知Web服务组合的动态演化框架,该框架包括Web服务容器层、服务组合编排层、上下文感知层、策略层、演化层五个层次。重点研究了上下文感知Web服务组合的动态演化技术,描述了上下文感知Web服务组合的动态演化实现机制,并对框架中各功能模块的作用进行了阐述。本文还给出了一个Web服务组合的BPEL流程到CCS进程代数描述的自动映射方法,并基于业务流程的CCS模型,对上下文感知Web服务组合的动态演化特性进行形式化验证,验证演化前后系统行为一致性和演化后服务间的行为相容性。最后,本文详细介绍了一个电子导游案例,展示了上下文感知Web服务组合动态演化的过程,同时采用本文提出的行为一致性和行为相容性验证机制对该系统的动态演化特性进行了实际验证。更多还原

【Abstract】 With the development of computer technology and Internet technology, service-oriented architecture is becoming a new architecture of distributed applications. As one of the means of achieving SOA, Web services and their composition are highly praised by the majority of vendors, organizations and research scholars. Especially with the development of sensor technology, everything on earth has become aware of each other and interoperable. Context-aware Web service composition is able to perceive the contexts and their changes of the user enviroment in real time, and then adjust the system behavior and provide services and computing resources for users proactively to reduce the human-computer interaction, improve the user experience and services pertinency. However, static Web service composition has been far from satisfying the needs of people because of the dynamic, open, changing and difficult controlled Internet environment. The ever-changing business environment also requires that the IT systems are able to rapidly adapt the changes of market demand and have the ability of dynamic evolution. It is with deep meaning that we combine the technologies of context-aware and dynamic evolution to research dynamic evolution model and methods of context-aware Web service in such environment.This paper proposes a dynamic evolution framework of context-aware Web service composition based on analyzing and summarizing the main framework of domestic and international dynamic evolution frameworks and deeply learning and researching the theory and technology of Web service composition, BPEL, context-aware, process algebra and dynamic evolution. The framework includes Web service container layer, Web service composition orchestration layer, context-awareness layer, strategy layer and evolution layer. It focuses on the dynamic evolution technology of context-aware Web service composition. This paper describes the dynamic evolution realization mechanism of context-aware Web service composition and the role of each functional module in the framework. This paper also provides an automatic mapping method from BPEL process of Web service composition to CCS process algebra description. Based on the CCS formal model of business process, behavioral consistency and behavioral compatibility of dynamic evolution of context-aware Web service composition are also verified. Finally, a case of E-guiding system is introduced to show the dynamic evolution process of context-aware Web service composition. And the dynamic evolution features of this system are verified with the behavioral consistency and behavioral compatibility verification mechanism proposed in this paper.更多还原