Controlled Flexibility in Workflow Management

Traditional workflow models are centered around the structure of a workflow. Other requirements and goals like time and cost can be represented only indirectly. As a result, when the workflow is executed, the WfMS can only enforce the structural constraints. This becomes a problem when the workflow deviates from its normal execution, e.g., due to errors or delays. In this paper we propose an approach to extend the definition of workflows which allows to make the underlying goals explicit. In addition, we introduce flexible elements into the workflow specification. We make use of these flexible elements in a controlled way to achieve a balanced fulfillment of all goals - structural as well as non-structural - under various runtime conditions.