reliability evaluation in tree-structured grid services with colored petri net

grid computing is an emerging computing paradigm that will have significant impact on the next generation information infrastructure. due to the largeness and complexity of grid system, its quality of service, performance and reliability are difficult to model, analyze and evaluate. this paper proposes a virtual tree-structured model of the grid service. this model simplifies the physical structure of a grid service because there are several links between rms and resources. in this paper, the task scheduling by rms and the task execution within grid resources considering data dependence and failure correlation are modeled using colored petri nets (cpns). we have also proposed a method for evaluation the grid service reliability based on the analysis of the model. in addition, an instance of the proposed model for a sample grid environment is constructed and analyzed using cpn tools.