The Study Of Changes And Implementation Mechanism In Dynamic Workflow

Workflow management technology is one of the latest technologies of computing in recent years. And it has already become a research focus of present IT field. At the same time, as the key technology of process management and process control in modern enterprise, workflow technology provides the whole framework including model analysis, model construction,model management and model running. However, with the development of actual application of workflow technology, the people find out that the workflow products cannot support the dynamic change of business demands, namely the workflow system lacks of agility and adaptation. The working mode of workflow can be divided into model construction stage and system running stage. As to the model construction stage, the workflow model is the abstract form of business process. And the workflow modeling is the basis of theoretical research and practical application.Firstly, this paper discusses the architecture of workflow management typical model and various modeling methods of workflow system entity. The workflow modeling and analysis techniques based on Petri nets was studied.Secondly, in this paper a dynamic workflow model was raised .As to the proposed model, the definition and the execution control of workflow model was discussed. To pledge the dynamic capacity, in this paper the dynamic workflow model definition language is based on XML and XML Schema, which can descript dynamic workflow model sententiously and truly.In fact, workflow system can't confirm all the processes, and the relationship among processes is not invariable. To confirm the dynamic characteristic, the system must has the ability of dynamic change. Based on others' studies about dynamic Workflow, we bring forward the theory and implement of dynamic change in dynamic workflow. Dynamic change operating set includes five type of model elements: workflow process activity, transfer information, global data, local data, defined data(data type is defined by user). For these model elements, three change operation are allowed: add model element, modify attribution information, delete model element. According to the object, dynamic change has two types: changing process definition, changing process instance. To pledge the workflow correctness and consistency(control and data), dynamic change is done in two aspects: control flow, data flow. According to control association and data association, thecorrectness and validity of dynamic change are pledged.Based on the study above, we present an approach to handle changes in dynamic workflow systems, we introduce efficient change handling algorithms that will incorporate certain modifications that must be made in the current workflow instance ,and based on the results, a new workflow instance will be generated accordingly. Then we introduce a case to validate our algorithms.