A dynamic service composition schema for pervasive computing

Pervasive computing, the new computing paradigm aiming at providing services anywhere at anytime, poses great challenges on dynamic service composition. Existing service composition methods can hardly meet the requirements of dynamism and performance for pervasive computing. This paper proposes a Petri net based service model to formally describe the function of services and employs a parameter based service description to represent both semantic and syntactic of services. And services are preaggregated in a two-layered graph according to the input and output parameters of the service description. Furthermore, we design a novel service composition scheme to achieve the user requirement through a tree search algorithm. The theoretical analysis and comprehensive simulation experiments show that both service model and composition scheme are correct and efficient.