Description Logic Based Composition of Web Services

Automatic service composition may dramatically improve development efficiency of Web Service applications. This paper proposes an approach to automatically process semantic and dynamic service composition using Description Logics(DLs) and AI planning techniques. Services and service composition problems are formalized with DLs to provide well-defined semantics. Four relationships among services as well as two combined service expressions are defined, with which AI planning techniques can be used to reason about how to compose services to achieve user-defined goals. We present an algorithm for automatic service composition, which uses backward-chaining search of potential services, and automatically eliminates irrelevant services while selecting, thus guarantee the execution efficiency. We also make some performance optimization of the algorithm such as removing redundant services and reusing previously achieved goals. All the composition steps could be done dynamically and automatically. Finally, we present an example to show how the algorithm works.