The specification of workflow activity multiple instances

Performing multiple instances of one activity will enable workflow management system to be flexible on handling workflow process. When handling multiple instances the main problem is the synchronization of workflow activity instances. After analyzing the assignment and the join of multiple instances, this paper describes the patterns of multiple instances, and classifies the basic patterns into four types. Then from the point of view control of instances joining, instance splitting and triggering the next activity instance, we pick four elements up that affect the process 's progress. The four elements can be used as the uniform denotation to show the characteristics of multiple instances. The formal presentation of activity attributes of multiple instances will enable a workflow engine to handle the activity instances simple and unifiable.