The Application Of Dynamic Workflow Based On Petri Net In OA System

In order to adapt to market competition, enterprises have to restructure business processes, standardize enterprise management, reduce production costs and improve productivity. How to develop the workflow, which satisfy different customer needs, have the ability of transaction processing and adapt to changing environment has become a hot research in the workflow technology.There are various models of workflow modeling, by comparing all kinds of models, we use Petri nets to model the workflow. Petri has a strong theoretical foundation of mathematics, which can describe the transaction process intuitively. This thesis improves a model validation algorithm to verify the rationality and correct of using Petri net model.Traditional workflow model the business process in the modeling build stage, identify business process-related tasks, the relationships between the tasks and the associated data; The implementation phase of the workflow, workflow process in accordance with the pre-defined flow direction with the participation of users. However, changes in the real world is complex, in the model building phase we cannot determine all the circumstances, therefore we need to develop dynamic workflow management system to adapt to the changing environment. This thesis analyses the dynamic of workflow, implements dynamic modification of the resources and process model, discusses the instance migration strategy and realizes the model instance migration.Now people consider the transaction mainly for the database, but rarely consider the transaction processing of workflow management system, when unpredictable exception occurs in the process, it cannot guarantee data consistency and atomicity, therefore the research of workflow transaction has a good practical value. This thesis introduces the method of database transaction, analysis workflow transaction model, and then analysis and compares it with the traditional transaction model and advanced transaction model. On the base of advanced transaction model, the thesis proposes a strategy which makes the workflow has the ability of transaction, proposes a bottom-up failure recovery algorithm which reduces unnecessary duplication of work and improve the efficiency of the system, implements transaction recovery processing using the behind code, so the workflow transaction is transparent to users, reducing the user difficulty to users.Petri net based dynamic workflow is applied to a small and medium enterprises OA system. Then introduces the design of database, all models of this system, the implementation of workflow management module in detail. This system achieves some results in the enterprise.