Study Of Policy Integtated Grid Workflow Management System

The grid technology is a completely new information technology, which makes it possible to overcome the inherent limitations of the traditional Internet technology. Since the advent of the concept and idea of grid, it has had a great impact all over the world. As many countries attach great importance to it, the grid technology has developed rapidly within only several years, and has been applied in practical fields of scientific research and engineering design.To provide reliable and predictable Grid services, Service Level Agreements (SLAs) are currently one of the major research topics in Grid Computing. SLAs define an explicit statement of expectations and obligations in a business relationship between provider and customer. Thus, SLAs should guarantee the desired and negotiated Quality of Service (QoS), which is a mandatory prerequisite for the Next Generation Grids.In this thesis, we discuss how to meet users' requirements by establishing SLAs. A policy adjuster integrated grid workflow management system is proposed to provide SLA guaranteed Grid workflow executions. The main contributions include an improved workflow management system with a policy adjuster mechanism comprised by a policy decision scheme, completion time estimation with similarity degree scheme, and a prototype implementation of this novel system architecture. Finally to evaluate our proposed system, we processed several experiments using a collaborative heart disease identification application to show the characteristics and advantages of our system. Through the results, we can see that our system achieves optimized performances in different cases according to various users' intentions so that the SLAs of Grid workflow applications are guaranteed.