基于动态描述逻辑的语义Web服务推理

Reasoning About Semantic Web Services with an Approach Based on Dynamic Description Logics

语义Web服务的提出是为了解决Web服务资源在语义Web中的自动发现、组合和执行等问题,基本思路是将本体承载的静态知识与对Web服务动态功能的描述有机地结合起来.动态描述逻辑是描述逻辑的一种动态扩展,支持面向语义Web的对动作的描述和推理.文中利用动态描述逻辑DDL(SHOIN(D))的描述和推理功能,提出对语义Web服务进行建模和推理的一种有效途径.从OWL-S中的Process Model出发,将语义Web服务建模为基于DDL(SHOIN(D))的动作理论,其中,对应于Process Model中的原子过程,可以对输入、输出、局部变量、前提条件、结果等多个方面进行建模;对应于Process Model中的复合过程,可以相应地对数据流以及顺序、选择、乱序、条件、迭代、循环等控制结构进行刻画.以建模后得到的动作理论为基础,应用动态描述逻辑的推理机制,可以分别对语义Web服务的可实现性、可执行性、投影、规划等问题进行推理.这些推理功能为语义Web服务的自动发现和自动组合提供了有效的支持.

The semantic Web services vision is to enable effective automation of various Web service related activities, such as Web service discovery, composition and execution. An obvious concern about the semantic Web service is to combine in some way the static descriptions of the information provided by ontologies with the dynamic descriptions of Web services＇ capabilities. Based on the dynamic description logic DDL（SHOIN（D））, this paper presents an approach to model and reason about semantic Web services. With this approach, the OWL-S ProcessModel of Web services will be firstly translated into an action theory which is based on the DDL（SHOIN（D））. This action theory allows for modeling atomic processes with their inputs, outputs, local variables, preconditions and results. It also offers considerable expressive power for modeling not only data flows of composite processes but also control flows such as the Sequence, Choice, Any-Order, If-Then- Else, Iterate, Repeat-While and Repeat-Until. Based on the action theory, the realizability, executability, projection and planning problems on semantic Web services can be reasoned about. These mechanisms provide effective supports for the discovery and composition of semantic Web services.