A graph-based approach enhancing correctness and speed of web services composition through explicit specification of functional semantics

Since most of studies on the automated composition of web services do not consider the functional semantics of services, unsatisfied results may be generated against users' intentions. Their time complexity is very high since every possible combination of available services must be considered. To enhance the correctness and speed of the composition of services, we propose a graph-based composition method, which explicitly specifies and uses the functional semantics of web services. A representative action, which represents what a service actually does, is identified. Data dependencies among available services are organised and stored as an AND/OR graph, on which service composition is performed. Rules are devised to map a service onto an appropriate action and to combine service actions. Effective pruning rules are also proposed. The experimental results demonstrate the superiority of the proposed method in terms of the correctness and speed of service composition.