Towards Temporal Controllabilities for Workflow Schemata

The modelling and management of temporal constraints over business processes has received some attention in the past years. Recently, we have introduced and discussed the concept of "controllability" for workflow schemata modelling real world business processes: controllability, originally introduced in the AI community for temporal constraint networks, refers to the capability of executing a workflow for all possible durations of all tasks. In this paper, we first extend the execution strategy proposed by Morris, Muscettola and Vidal in the context of temporal constraint networks, to deal with the execution of business processes in a more suitable way. Then, we discuss and propose a new algorithm to deal with the (dynamic) controllability of an overall workflow schema, where several, possibly disjoint, execution paths are possible, due to the presence of alternative paths in the workflow schema. We show that the presence of several controllable alternative execution paths in a workflow schema does not guarantee that the overall workflow schema is controllable.