SEMANTICFLOW: A SYSTEM FOR FLEXIBLE WORKFLOW EXECUTION

Workflow management systems received considerable attention lately, motivated by their wide spectrum of applications. Requirements for workflow management systems comprise a long list, among which one may highlight distributed execution, cooperation and coordination, and synchronization, that model the way user communities work cooperatively to perform a given task. This doctoral dissertation addresses a complementary family of requirements, collectively called flexible execution . Briefly, workflow management systems usually interpret a workflow definition rigidly. However, there are real life situations where users should be allowed to deviate from the prescribed sequence of actions for various reasons, including the unavailability of required resources. To cope with situations such as this, mechanisms to flexibilize workflow execution are proposed, that allow execution to proceed in the presence of incomplete information, by adopting presuppositions, and in the presence of negative information, by suggesting execution alternatives. An implementation of the mechanisms, that extends known Web service frameworks, is also outlined.