Decentralized management of dynamic and customized workflows

With the rapid growth of Internet applications for enterprise-wide and cross-enterprise business processes with dynamically changing participants, workflow management systems (WFMS) face various challenge. This dissertation has contributed to the progress towards the formalization and development of a decentralized workflow system that supports customized workflows that can be automatically composed at design time, and adds greater flexibility for dynamic workflows that can adapt to the changing requirements and environments. This dissertation also has contributed to the progress towards the understanding of requirements and limitations in developing inter-agency E-government application systems. The specific technical contributions of this research are as follows:; First, the issues of autonomy and scalability are addressed with the decentralized workflow management model that enforces intertask dependencies without the need for a centralized WFMS. The decentralized execution in our model is achieved with self-describing workflows and WFMS stubs.; Second, this dissertation identifies conflict-of-interest problems that may arise in a decentralized workflow execution environment, where a task execution agent may take advantage of others by manipulating the semantics of the workflow. This dissertation proposes a decentralized workflow Chinese Wall Security model that supports fair execution of a workflow in a decentralized manner, where restrictive partitioning and secure dependency splitting algorithms are proposed so that sensitive data is protected from the agent within the same conflict-of-interest group.; Third, to support automatic on-the-fly composition of customized inter-organizational workflows, this dissertation develops an ontology-based dynamic workflow generation model. This model utilizes a conceptual ontology of component services (tasks), a topic ontology of domain composition knowledge that hierarchically structures workflow composition rules according to the given topic concepts, and user profile.; Fourth, to handle run-time changes and exceptions for providing flexibility in a workflow system, this dissertation provides a dynamic change managment model. Our model includes the specification of a change request with controlled vocabulary derived from concepts in an ontology, a workflow context manager (ConMan) and Self Adaptor . (Abstract shortened by UMI.)...