Verified Service Compositions by Template-Based Construction

Today, service compositions often need to be assembled or changed on-the-fly, which leaves only little time for quality assurance. Moreover, quality assurance is complicated by service providers only giving information on their services in terms of domain specific concepts with only limited semantic meaning. In this paper, we propose a method to construct service compositions based on pre-verifiedtemplates. Templates, given as workflow descriptions, are typed over a (domain-independent) template ontology defining concepts and predicates. Templates are proven correct using an abstract semantics, leaving the specific meaning of ontology concepts open, however, only up to given ontology rules. Construction of service compositions amounts to instantiation of templates with domain-specific services.Correctness of an instantiation can then simply be checked by verifying that the domain ontology(a) adheres to the rules of the template ontology, and (b) fulfills the constraints of the employed template.