Modelling extensions for concurrent workflow coordination

Business processes exhibit concurrent execution, where different and sometimes inter-dependent parts, are isolated and run in parallel. In current workflow tools, this requirement is supported through a synchronisation mechanism allowing for the convergence of parallel paths of execution. In this paper we argue that more sophisticated forms of inter-process communication are necessary for increased workflow automation. In particular three extensions which preserve the parallelisation of execution paths are proposed: the adaption of synchronous and asynchronous messaging for data/document flow across execution paths, aborts of related execution paths, and exclusive, i.e. atomic, execution of nested processes. Illustrations from an industrial case study show how these constructs combine with classical workflow constructs to capture complex but common themes of business processing. To precisely impart the ramifications for workflow execution, we show how a formal semantics can be assigned for the constructs