Service Refinement

Summary form only given. This paper presents a refinement calculus for service components. We model the behaviour of individual service by a guarded design, which enables one to separate the responsibility of clients from the commitment made by the system, and to identify a component by a set of failures and divergences. Protocols are introduced to coordinate the interactions between a component with the external environment. We adopt the notion of process refinement to formalize the substitutivity of components, and provide a complete proof method based on the notion of simulations.