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题名:
Web服务复合的若干关键问题研究
作者: 任志宏
答辩日期: 2003
专业: 计算机软件与理论
授予单位: 中国科学院软件研究所
授予地点: 中国科学院软件研究所
学位: 博士
关键词: 面向服务的体系结构 ; Web服务复合 ; 复合元模型 ; Web服务复合验证 ; Web服务复合执行语义
其他题名: Research on Web Service Composition Technologies
摘要: 随着以、Veb服务为基础的面向服务的体系结构的发展,如何复合分布的、自治的Web服务构筑新的企业业务应用的问题也成为软件工程领域一个新的热点问题。利用Web服务复合技术,企业业务应用可以获得极大的敏捷性。但是,Web服务复合技术的研究刚刚起步,在复合建模、结构验证、执行语义和支撑框架等方而的研究尚不充分;本文针对这些不足展开研究。本文首先提出了一个基于属性图理论的Web服务复合模型—WSCG模型,改进了现有、Web服务复合模型在可视化表示能力和执行语义的确定性等方面的不足;模型包括Web服务复合的可视化表示模型和执行模型两个方面。其次,基于属咨吐图文法,本文给出了由WSCG文法描述的、Veb服务复合元模型,对WSCG模型的设计过程进行约束,形成一种以属性图文法导向的WSCG模型设计方式;不但保证了用户可以生成符合规范的WSCG模型,而且消除了WSCG模型在结构上可能引发死锁的部分原因。同时,我们也给出了WSCG模型的形式化定义。在WSCG模型的基础上,针对目前Web服务复合模型缺乏良构性验证的问题,在WSCG模型的静态特性验证方面,我们定义了WSCG模型的类型安全性,并给出了相应的WSCG模型全局类型安全性的验证算法,解决了验证WSCG模型中输入输出消息集合的类型是否匹配以及输入消息是否是完备的问题;在WSCG模型的动态特性方面,我们主要分析了WSCG模型的可达性、活锁和死锁问题。不但给出了WSCG模型的可达性分析方法和活锁检测方法;而且.通过定义WSCG模型的依赖关系图,模拟WSCG模型的执行过程中的控制依赖和数据依赖关系,设计了基于依赖关系分析的WSCG模型死锁检测算法,检测WSCG模型有无死锁存在。本文还在统一的属性图变换理论框架内研究了WSCG模型的执行语义,以保证WSCG模型的执行实例和WSCG设计模型的一致性。WSCG模型的执行语义有两种描述方式,一种是定义在WSCG元模型之上的基本的执行语义,这是WSCG模型进行解释执行的基础。除了定义在元模型之上的执行语义,通过扩展WSCG模型基于事件的可执行框架中提供的三类用户定制事件,用户亦可以定制面向领域应用的用户定制执行语义,提高WSCG模型的适用性。论文也通过构造变换产生式集合的并行不相关割集和变换产生式的顺序不相关集合,设计了WSCG模型的执行算法,改善执行效率。最后,本文从软件复用角度出发,基于WSCG模型,设计了Web服务复合的葵本框架—WSCG Framework。Web服务复合框架涵盖了Web服务复合模型表示、WSCG模型、WSCG变换和WSCG验证四个方而的内容。同时,基于WSCG Framework我们设计并实现了支持Web服务义合模型的设计、验证和执行的原型系统,并给出了原型系统的总体结构,描述了其中的关键部件,如 WSCG Editor、WSCG协调者、状态管理器、Web服务代理和WSCG对等点服务的设计思路和具体实现技术。
英文摘要: With the evolution of service-oriented architecture, providing support for compositing distributed and autonomous web services into business applications has become a key area in the software engineering research. Agility of business applications will be obtained through utilizing web services composition technologies. However, at this stage, the research on these emerging technologies does not solve the necessary problems to build web service compositions, especially in web service composition modeling, composition verification, executable semantics and supporting systems. In this thesis, we investigated several key issues of web service composition. Firstly, WSCG (Web Service Composition Graph) model, a model for web service composition, is proposed, which consists of visual presentation model and executable model. According to this model, the interactions and execution sequences among web services are characterized by WSCG nodes and edges and their attributes. Based on attributed graph theory, we give the formal definition of WSCG model. Secondly, based on attributed graph grammar theory, we present a meta-model named WSCG grammar for WSCG model. Elements, elements' attributes and elements' relationships of WSCG model are all defined in WSCG grammar. Directed by WSCG grammar, a WSCG model can be developed, which can satisfy the specification of WSCG model and eliminate some structure errors. To ensure the well-formed of WSCG model, we have developed an algorithm to check the type-safety of WSCG model, in which data edges of WSCG model can be used to check whether the export messages of an edge's source node is matched with the import messages of the edge's target node, and to determine whether the import messages of a node is self-contained. We also develop another algorithm, which is based on WSCG dependence graph that simulates the WSCG dynamic behaviors, to eliminate the deadlock of WSCG model. Using attributed graph transformation productions defined on WSCG model, the consistency between WSCG execution instance and WSCG model is guaranteed with a sound formal semantic basis. The executable semantics of WSCG model can be classified into two types, the one type is defined on WSCG meta-model, and the other type is domain-oriented, whose executable semantics are customized by extending the event handle in executable model. To improve the execution performance of WCSG model, all transformation productions, which express executable semantics of WSCG model, have been divided into several parallel independent disjoint set, and sequential independent sets for every transformation productions are also defined. Lastly, to support, facilitate and assist the visual design, verification and execution of web service composition, we present WSCG framework that includes web service composition model design, WSCG model, WSCG transformation and WSCG verification. At the same time, WSCG toolset and WSCG runtime, prototype systems for proposed framework, are implemented in J2EE environment. We outline the architecture of both prototypes and detail the design and implementation of components of prototypes, such as: WSCG editor, WSCG coordinator, state manager, web service broker and WSCG peer service.
语种: 中文
内容类型: 学位论文
URI标识: http://ir.iscas.ac.cn/handle/311060/7050
Appears in Collections:中科院软件所

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Recommended Citation:
任志宏. Web服务复合的若干关键问题研究[D]. 中国科学院软件研究所. 中国科学院软件研究所. 2003-01-01.
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