Formal Approach for Compatibility Checking of Orchestrations of Composite Semantic Web Services Web service composition is the process of combining Web services in order to offer valueadded services that meet the increasing complex requirements of business processes. Besides simple Web services described with WSDL, OWLS language allows to describe composite semantic Web services offering multiple operations using complex control structures. However, it becomes harder to manually check the consistency of orchestrations of such services in order to guarantee their correctness and avoid deadlock and erroneous statuses. In this paper, we first propose a formal method for translating OWLS composite services into communicating automata using an iterative process which is driven by the control structure of that language. The same approach is also applied to the orchestrator whose description is given in WSBPEL. Thereafter, we build up the synchronization product of the resulting automata and proceed to its consistency checking in order to unveil any forbidden statuses which depict flaws in that orchestration interaction protocol.

Formal specification and validation of refinement from WSCDL to BPEL Service composition is a primary task in the development of serviceoriented systems. The Web Service Process Execution Language (WSBPEL) and the Web Service Choreography Descriptor Language (WSCDL) are two major languages for Web services modeling and implementation. Although these two composition models are of a different nature, they are complementary. WSCDL serves as a behavioral modeling language for collaboration between multiple participants (web services) within the same business process from a global point of view. However, WSBPEL allows a service composition process to be described at different levels of abstraction. At a high level, the description follows a global point of view and deals only with the exchange of messages between participating abstract services (represented abstractly by roles). WSCDL descriptions are thus considered as a specification of the abstract service composition from which more concrete WSBPEL processes are extracted. In this article, we present a formal modeling and analysis approach based on sequential communication process (CSP) in order to verify the behavioral consistency between abstract choreographic descriptions and executable BPEL processes, thereby proving the correctness of the translation process.