Ontology-based Portfolio Of Services: Dartflow Design And Realization

With the emergence of technologies and standards supporting the development of web services, more and more services are becoming available on the Internet. But almost all of them are single and simple functional units. Composing existing services into new functionality becomes very essential for enterprises. Accordingly researchers are pursuing the service composition to compose existing services to large and complicated ones. But most of the existing projects and frameworks on service composition use static modeling. However the internet is dynamic and full of changes, those projects and platforms are not flexible enough to execute stably. This paper presents an ontology-based service composition framework-Dartflow. The mainly job of this paper is on following aspects.1. Ontology-based service registration. The internet resource can be described accurately and effectively by ontology. We can find a web service quickly and accurately by binding ontology to web service. The Dartflow framework registers the web service to service repository by building the relationship between the service and the ontology. A user tool is designed to build this relationship. Also we use ontology service definition language (OSDL) to describe this relationship. We store the service definition into the database by parsing the osdl file.2. Workflow-based Service composition mode. During the process of designing service composition, a detailed comparison between service composition and workflow is introduced in this paper. According to the similarity of these two systems, we call the business process of service composition as serviceflow and use the workflow system for reference.3. Dynamic service definition support. This paper divides the serviceflow to static serviceflow and dynamic serviceflow according to the bind service. A static serviceflow has concrete service in the activities and a dynamic one has abstract service which is described by the searching conditions using ontology. This paper presents an Ontology Service Query Language (OSQL) to describe the ontology-based searching condition. A new service composition modeling language-ServiceFlow Definition Language (SFDL) is designed to describe the serviceflow which supports the dynamic service composition. Including basic activities, three structured activities (flow, switch and sequence) is defined in SFDL. Also this framework provides several graphic tools for user to define a serviceflow easily and quickly.