Research And Implement Of Dynamic Workflow Based On Open Grid

With the development of Internet and computer science and technology, Open Grid Services Architecture is developed fast. More and more applications require using resources and services under OGSA comprehensively and automatically. How to achieve this goal is an important aspect of research in grid techniques.The services in grid are usually simple, far away from applications'requirements. Workflow is one of the mature ways to combine services. But it is usually confined itself to close systems. What's more, it has several limitations. There will be workflow management problems if it is applied to open systems directly.As respect to the dynamic feature and openness of grid environment, dynamic workflow is a good way to both satisfy applications'requirement and adapt to service properties. The thesis focuses on dynamic workflow. Research work covers three aspects and some results are shown as it follows: (1) With further analysis of production system and Petri Net, dynamic workflow is formally described. Production system is used to present logical features of dynamic workflow, while Petri Net is used to describe dynamic features of dynamic workflow. Due to potential conflicts in workflow modification, the thesis proposes ways to solve the problem. (2) Functionalities in each node in dynamic workflow are usually fulfilled by nested service calls. Services concerned are distributed in grid environment and nested service call is constructed dynamically in workflow runtime. In order to solve potential conflicts in nested service call, a nested call conflict discovery algorithm is put forward. Further, the algorithm is optimized. (3) In GT3 platform, a simple dynamic workflow is developed and the nested call conflict discovery algorithm is implemented, too. Steps to develop dynamic workflow are manifested in detail.The thesis research work is supported by Hi-Tech Project for Universities in Jiangsu (Grant No: JH02-074).