Study Of Process Integrity Control For Migrating Workflow

Migrating workflow becomes a new research trending of workflow nowadays, and by implementing with mobile agent technology it's fit for distributed and concurrent interaction which is in frequent disconnecting environment and with enormous invocations to remote services. Migrating workflow contains three elements as workflow engine, migrating instance and workplace. Migrating instance (MI) is the executor of workflow and based on mobile agent so that it can carry code and data to migrate onto different workplaces to call local services to fulfill process. Workflow engine is responsible for defining workflow, maintaining overall information and creating migrating instances.Migrating workflow should support three transactional properties as failure atomicity, workflow isolation and workflow data consistency. Migrating workflow process integrity means that all tasks keep failure atomicity and finish following workflow specification so that main process and sub processes should be executed completely and so as each task. Process integrity control for migrating workflow (MWPIC) controls two levels, and firstly it will work out to keep integrity of task block, and then it will control the integrity of process. MWPIC has two implications, and firstly it should be equipped with failure recovery facilities to make each task completely executed, and secondly it should follow the dependency relationship between tasks to keep process integrity as specified.Task block integrity control (TBIC) will firstly describe composition of task block with a spanning tree, and then label task states on tree nodes and summarize task block state with and-or logic. Finally the task block will be decided how to do migrating recovery according to spanning tree. So the TBIC algorithm is proposed in the paper.MWPIC algorithm depends on TBIC, and for whole process it will derive multiple MIs for branch sub-processes, while merging them for aggregation. By recursive deriving, the minimum sub-process is transformed into serial task blocks. So the MWPIC algorithm is proposed in the paper.To verify the MWPIC algorithm it is fulfilled on migrating workflow management system in mobile computing lab. With experiment result, it is illustrated that MWPIC makes the whole process keeping continuous working to a final accomplishment careless the external exceptions and enhances the system stability.The algorithm presumes there are plenty of workplaces supporting for migrating recovery so that its efficiency may be lower on realistic circumstances. So the algorithm needs to be improved. What's more, the algorithm pays main attentions to workflow integrity without any to data correctness and consistency. How to combine integrity and correctness solutions together to enrich the realization model of transactional properties of migrating workflow is a problem requiring future study.