Inter-operability of Workflow Applications: Local Criteria for Global Soundness

Automatic analysis techniques for business processes are crucial for today's workflow applications. Since business processes are rapidly changing, only fully automatic techniques can detect processes which might cause deadlocks or congestion. Analyzing a complete workflow application, however, is much too complex to be performed fully automatically. Therefore, techniques for analyzing single processes in isolation and corresponding soundness criteria have been proposed. Though these techniques may detect errors such as deadlocks or congestion, problems arising from an incorrect inter-operation with other processes are completely ignored. The situation becomes even worse for cross-organizational workflow applications, where some processes are not even available for analysis due to confidentiality reasons. We propose a technique which allows to detect but a few errors of workflow applications which arise from incorrect inter-operation of workflows. To this end, the dynamics of the inter-operation of different workflows must be specified by the help of sequence diagrams. Then, each single workflow can be checked for local soundness with respect to this specification. If each single workflow is locally sound, a composition theorem guarantees global soundness of the complete workflow application. This way, each organization can check its own workflows without knowing the workflows of other organizations--still global soundness is guaranteed.