Specifying web workflow services for finding partners in the context of loose inter-organizational workflow

This paper deals with Web Workflow Services (W2S) description languages that help organizations to rind partners in the context of loose Inter-Organizational Workflow (IOW). Loose IOW refers to occasional cooperation between organizations, free of structural constraints, where the partners involved and their number are not pre-defined. Such a dynamic and heterogeneous context requires the definition of a W2S description language allowing workflow service providers to publish their capabilities and workflow service requesters to express their needs. Current Web services languages do not permit to describe adequately workflow services (structure and behavior) by lack of expressive power and/or formal semantics. In this paper, we show how the appropriate combination of Petri Nets with Objects (PNO) and OWL-S allows the specification, validation and publication of workflow services. On the one hand, PNOs permit the formal and graphical specification of workflow services, their simulation and validation. On the other hand, OWL-S permits the publication of workflow services on the Web. OWL-S has also the advantage to include the ontology concept which can be used to solve semantic problems between IOW partners. Moreover, we provide rules and algorithms which automatically derive OWL-S specifications from PNOs ones. This work has been implemented.