Grid Service Workflow Models and Their Equivalent Simplification Methods

In this paper, we propose a grid service workflow model framework based on stochastic Petri net (SPN) and equivalent methods to simplify the complex service workflow model to a simple model. In our models, the grid service can be of inner services and exterior services. The exterior service will be published to the users and the inner one needs not to be published. The models are expressive enough to capture the inner information of complex service combinations and their respective specificities. The obtained framework enables declarative composition of grid services. It shows dynamic and transient relationships among services. On the other hand, by the equivalent simplification to the models, the inner information of complex services can be protected, and the computation and analysis course can be simplified for the grid service workflow