A Model for Web Services Data in Support of Web Service Composition and Optimization

Automatic Web services composition has attracted much attention in recent years with the focus on control flow specification. Data mismatch between WSs is often considered as an orthogonal problem that can be solved using XML data model and query languages, e.g., XQuery. We argue that Web services composition and data manipulation should be considered holistically such that further optimization on Web service composition become possible. In this work, we de fine a model, called K'S-data model, for composing WSs with focus on their data exchanges. We propose several operators that can be used to compose WSs and manipulate the generated data. Properties of these operators are discussed and an example is given to show how these properties can he utilized to identify a more efficient way for realizing a complex task expressed using a WS-data expression.