A workflow system based on Meta Services in Grid environments

A workflow consists of multiple and various working processes, and a workflow system manages and executes the workflow. If the workflow is managed in Grid environments, it is processed effectively by using many Grid resources. In this paper, we present a workflow system which manages workflow operations in Grid Environments. The workflow model is divided into three layers - service, flow, and task layer - for reusability and scalability of workflow. The service layer is based on a concept of Meta Services for increased reusability. Users can access the workflow through this service layer, and they execute the workflow by calling their services defined by the Meta Services. The flow layer and task layer are separated for independency between the task descriptions and workflow logic connecting the tasks. A GUI workflow editor is also provided for users' convenience. Therefore, this middleware uses Grid resources effectively and provides convenience to users.