Abstract
► Service dependencies are set up in the form of Horn-clause using hypergraph theory. ► Service composition problem is transformed into logical inference of Horn clauses. ► Both data type and constraint compatibility are considered when composing services. ► Existence of composite services is determined in time linear in the size of clauses. ► Structural analysis techniques of Petri nets are used to obtain composite services.
This paper introduces an automatic Web service composition method based on logical inference of Horn clauses and Petri nets. The Web service composition problem is transformed into the logical inference problem of Horn clauses by exploring the dependency relations among services. An algorithm is presented, to determine whether the composite service exists in time that is linear in the size of the knowledge base. It can also return the rule set necessary for the composition. Petri nets are chosen to model the rule set and its structural analysis techniques are used to obtain the composite service.