Hagen Overdick, Frank Puhlmann, and Mathias Weske: "Towards a Formal Model for Agile Service Discovery and Integration", International Workshop in Dynamic Web Processes (DWP, 2005)

As the fundamental web services technologies are becoming mature, web service composition, orchestration and choreography are gaining increasing attention. The movement from static interactions between already known partners as in BPEL to dynamically discovered and agile business partners is irresistible facing ever changing environments while aiming for specifically optimized collaborations. However, the techniques and models currently used lack fundamental formal foundations making them inadequate especially for modeling non-functional aspects. As a step toward the vision of dynamically discovered and agile processes, this paper proposes a formal approach to unambiguously define the syntax of service orchestrations and choreographies by representing key elements of service--oriented computing in a process algebra, the $\pi$-calculus. The results include a formal description of correlations in the context of service choreography as well as a formal representation of an orchestration pattern derived from BPMN and BPEL. The results provide a better understanding of service-based processes in terms of a formal algebra that will open the door for automated discovery and binding of potential business partners via service equivalence and mobility.