提出了一种利用动态描述逻辑(DDL)的动态推理自动组合Web服务的方法。DDL是描述逻辑(DL)的一种动态扩展,它结合本体提供的静态信息与Web服务提供的计算,统一地描述和推理Web环境中静态信息与动态知识。该方法充分利用Web服务组合中涉及的静态知识(如描述逻辑知识库刻画的领域公理、具体环境和用户需求等)和动态知识(DDL中动作刻画的Web服务的功能),将Web服务组合的问题归约为DDL公式的可满足性问题,并通过一个可判的表扩展算法解决。开发了基于动态描述逻辑D—ALCHOQ的原型系统,并针对旅行代理问题的实验初步证实了该方法的可行性及潜在的应用前景。
This paper presents a new method for automatic Web service composition (WSC) based on the dynamic reasoning in dynamic description logics (DDL). DDL is a dynamic extension of description logics (DL), which couples the static information provided by ontologies and the computation provided by Web services to provide a mechanism for representing and reasoning of both static and dynamic aspects of the Web. This approach employs the classical knowledge base in DL to capture the domain constraints, and actions in DDL are used to abstract the functionalities of the existing Web services which are classified into categories in terms of their functionalities. In such a way, the WSC problem can be reduced to the problem of formula satisfiability, and it can be solved by a decidable tableau procedure. A reasoning engine based on the dynamic description logic D-ALCHOQ was implemented, and the presented approach was tested on a simple variation of the travel scenario. The preliminary results proved the feasibility and the application potential of the approach.