【作者】 胡佳；

【导师】 冯志勇；

【作者基本信息】 天津大学 ， 计算机应用技术， 2010， 博士

【摘要】 面向服务体系架构(Service-Oriented Architecture, SOA)和面向服务计算(Service-Oriented Computing, SOC)的出现,为分布式应用和企业信息系统集成提供了一种灵活的解决方案。由于单个Web服务功能的有限性,如何组合多个Web服务来共同完成一项任务已经成为工业界和学术界广泛关注的焦点问题。同时,通过将Web服务技术和语义Web技术相结合,产生了多种语义Web服务描述框架,使Web服务自动发现、组合、验证及执行的实现成为了可能。本文结合国家863课题“面向解决方案的服务架构及支撑环境”,对语义Web服务组合的关键技术,包括Web服务发现、Web服务自动组合以及Web服务流程验证的方法进行了深入的研究,主要研究成果包含以下几个方面:(1)研究了Web服务之间的关系,完善了服务网络的概念。结合语义Web服务的相关技术,从服务功能的角度,提出了抽象服务和具体服务的概念,以及按照参数、操作、具体服务和抽象服务四个层次分析、定义了Web服务在不同粒度间潜在的关系,并在此基础上给出了服务网络的概念框架和系统结构。(2)研究了信息类语义Web服务组合问题,提出了基于GraphPlan的启发式服务组合算法。该算法根据信息类Web服务的特点,将服务组合划分为规划图构造和组合方案搜索两大模块,能够在多项式时间内判断服务组合的可满足性。在规划图的构造过程中充分考虑了服务网络中丰富的关系信息,并且在组合方案搜索模块中,使用了一种启发式服务选择策略。(3)研究了同时包含信息类和状态改变类Web服务的混合类服务组合问题,设计并实现了基于抽象模板的服务自动组合系统。该系统面向服务网络中的抽象服务层,其主要工作是根据用户的功能性需求,通过充分复用过去解决用户需求问题的经验,并配合模板的预处理和启发式自动调整算法,完成一个抽象服务组合流程的构建工作。实验表明,在相同的外部环境下,该系统能在较短时间内实现服务的自动组合,并且随着服务数量的增加,能够表现出较好的适应性。(4)研究了语义Web服务组合的验证问题,提出了基于Petri网的服务组合一致性验证方法。该方法能够在服务部署前发现组合逻辑上潜在的不一致性,从而提高了服务组合的健壮性和用户满意度。并且通过一个实际案例验证了本方法的正确性和有效性。更多还原

【Abstract】 The emergence of Service-Oriented Architecture (SOA) and Service-Oriented Computing (SOC) provides a flexible solution for building distributed applications and integration of enterprise information systems. Because of the limitation of the function of a single Web service, how to combine multiple Web services together to complete a complex task has become the key concern of industry and academia. At the same time, by combining the technologies of Web service and Semantic Web, a variety of semantic Web service frameworks are proposed, which can be used to enable the automated Web services discovery, composition, verification and implementation.Under the support of the national 863 project "solution-oriented service architecture and supporting environment", we study in-depth the key approaches for Semantic Web service composition, including Web service discovery, Web service composition and Web service process verification. The main contributions of this paper are listed as follows:1) We studied the relationship between Web services and improved the concept of service networks. In combination with the technologies related to semantic Web services, and from the perspective of service functions, we presented the concepts of abstract service and concrete service. Beside this, we analyzed and defined diferent potential relationships respectively in four different levels of granularity including the parameter, operation, concrete service and abstract service levels. And finally, we gave the conceptual framework and system architecture of the service network.2) We studied the problem of the composition of information providing Web services, and proposed a GraphPlan based heuristic algorithm for service composition. Based on the characteristics of the information providing Web services, the algorithm divided the service composition process into two phrases including service planning graph creation and solution searching, and can determine the satisfiability of the problem of service composition in polynomial time. In the course of the construction of the service planning graph, we took full account of relationship information in the service network, and the algorithm of the solution searching was designed to utilize a novel heuristic selection strategy.3) We studied the problem of the hybrid service composition which included both information providing services and world state changing services, and proposed a service composition system based on the abstract template. This system is only concerned with the abstract services in the service network, and given a user’s functional requirement, it can complete the construction of an abstract service composition process throuth reusing the past experiences of solving the old similar requirements or by the template preprocessing and heuristic template adaptation. Experimental results showed that in the same external environment, our system can achieve the service composition task in a relatively short time with the increasing of the number of services, and have a better flexibility.4) We studied the problem of the verification of the semantic Web service processes, and proposed an consistence verification approach based on Petri nets models. This approach can find the potential logical inconsistence of the semantic Web service process before the deployment of it, thus enhancing the robust of the process and the users’satisfaction. And through a practical case, we proved the correctness and effectiveness of this approach.更多还原