Specifying complex process control aspects in workflows for exception handling

Contemporary specification languages of workflow management systems focus on capturing process execution semantics. Constructs are offered that allow the specification of sequential execution, iteration, choice, parallelism and synchronisation. While in workflow modelling it is absolutely imperative that exceptions are dealt with properly, virtually no support for the specification of exception handling is offered at the conceptual level. Typically, exceptions and recovery strategies need to be defined using the programming primitives of the specific workflow management systems used. We propose a number of conceptual modelling primitives that can be used for the specification of exception handling in workflows. These primitives are illustrated using some real-life examples. A formal semantics is assigned to precisely define their meaning and demonstrating how they can be incorporated in a typical process modelling language