Research On Dynamic Grid Workflow Model Based On Service

With the Grid technology's rapid improvement, its application fields are wider and wider, and its size becomes larger, and more comeplicate. Comeplicate Grid applications may have various restrictions and resource competing problems. Grid Workflow is introduced into The Grid in order to construct, execute, manage, and monitor the Grid applications conveniently. Because Colored Petri Net is intuitionistic, formalizing and powerful analyzing capacity, and sustains data structure and layer decomposing, so it is more suitable as a tool of Grid Workflow modeling by comparing and analyzing Grid Workflow's modeling methods.A feasible Grid Workflow system framework model is introduced in the paper, based on an in-depth study on the Grid technology, the Grid Service and the Grid Workflow's concepts, characteristics and their applications. This model takes the dynamic characteristic of Grid into account sufficiently. In this thesis, the work focuses on Grid Workflow modeling,dynamic optimizing and dynamic scheduling.In order to refine the model of Grid Workflow, DCP-Net(Dynamic Colord Petri Net) as a tool of Grid Workflow is defined by adding dynamic element to Workflow Net and Colored Petri Net. Subsequently, it is analyzed. It proposed the Model optimizing methods, and analyzed the optimizing effect by example. In order to examining the model and optimizing the methods' validity, a dynamic scheduling arithmetic is designed. The experiment shows that using the model can satisfy users' demand and improve resource utilization.In this thesis, ECWF-Net(Extended Colored Workflow Nets) with time price information as a modeling tool is defined, and Reachable Scheduling Graph arithmetic given, in order to analyze Grid Workflow's schedulability, time performance and cost, can be used to solve the state explosion problem; Moreover, Broadening arithmetic is also bring forward to adjust unreasonable constraints; Dynamic scheduling arithmetic and idea are analyzed , Priority function is introduced to solve conflict problem, and enhance workflow's time performance, and dynamic analyze, choose path and adjust constraints to optimize scheduling during executing Grid Workflow. It is concluded that the model can effectively save time and cost, and improve execution success ratio by simulating.