%K Web services ?  WSDL  ?  WS-BPEL  ? Process calculi ? Type systems 
%R 10.1007/s10703-010-0110-0
%P 119-157
%I Springer
%O ? Springer Science+Business Media, LLC 2010. The original publication is available at www.springerlink.com. The work presented in this paper is a much extended and revised version of Lapadula A, Pugliese R, Tiezzi F (2006) A WSDL-based type system for WS-BPEL. In: COORDINATION. LNCS, vol 4038. Springer, Berlin, pp 145?163.  http://eprints.imtlucca.it/id/eprint/419
%D 2011
%V 38
%N 2
%L eprints401
%A Alessandro Lapadula
%A Rosario Pugliese
%A Francesco Tiezzi
%J Formal Methods in System Design
%T A WSDL-based type system for asynchronous WS-BPEL processes
%X We tackle the problem of providing rigorous formal foundations to current software engineering technologies for web services, and especially to WSDL and WS-BPEL, two of the most used XML-based standard languages for web services. We focus on a simplified fragment of WS-BPEL sufficiently expressive to model asynchronous interactions among web services in a network context. We present this language as a process calculus-like formalism, that we call ws-calculus, for which we define an operational semantics and a type system. The semantics provides a precise operational model of programs, while the type system forces a clean programming discipline for integrating collaborating services. We prove that the operational semantics of ws-calculus and the type system are ?sound? and apply our approach to some illustrative examples. We expect that our formal development can be used to make the relationship between WS-BPEL programs and the associated WSDL documents precise and to support verification of their conformance.