Semantic Annotation Based Service Composition for Grid Workflow Description and Execution

The main purpose of the research work presented in this paper was to model and implement a workflow based architecture for Web service composition which allows the integration of composed Web services in a Grid middleware. The composed Web services are integrated as computational nodes in a workflow description and execution platform. To prove the presented theoretical concepts, a prototype was also implemented based on the gProcess application in which the Web services are integrated as satellite image operators in workflows used for processing satellite images. The urge for such a research work was driven by the lack of flexibility offered by the static deployed applications and the need of a dynamic approach given by Web services developed and deployed all over around the world. The proposed solution is a semi-automatic Web service composition based on predefined templates and realized in several steps: automatically search in a private registry, perform semantic annotation, automatically bind information of founded services and create a BPEL business process. This solution offers a dynamic approach and allows a high degree of reusability and interoperability in a Grid medium.