Modeling cost-aware services composition using a priced formal method

Process algebra have been effectively exploited for modeling and verifying functional aspects of services composition, but non-functional aspects have not been given enough care due to process algebra lacking of capability of modeling them. In this paper, we propose a novel process algebra called PTPA that incorporates price and cost. We present syntax and semantics of PTPA. And an algorithm is proposed to construct cost state space that is used to select web services composition with optimal cost. Case analysis show that PTPA can model both functional aspects and non-functional aspects of services composition.