Web service composition algorithm based on fix-point theorem

Abstract

A number of web services are now available and it therefore seems natural to reuse existing web services to create composite web services. The key to the problem of web services composition is how to model the input and output data dependency of candidate web services and how to satisfy that of a service request by composition efficiently. In this paper we propose an algorithm based on the concept of invocation layer and Knaster-Tarski fixpoints theorem, which can be used to get the least invocation layers of candidate web services to satisfy the given service request. Then we design another search algorithm based on A*procedure to find the best composition ways according to the invocation layers.