Improving dynamic Web service selection in WS-BPEL using SPARQL

The dynamic selection of Web services must be able to adapt to a changing environment as services are permanently inserted, removed and modified. However, most composition languages do not support such dynamic selection, or support it in a restrict sense, as in WS-BPEL. In this work we employ available technologies, especially the WS-BPEL and SPARQL languages, in order to develop a model for the dynamic selection of Web services. In this model the user expresses the service requirements in the form of a query that will be resolved at runtime. This guarantees the adaption of the system - in a changing environment - without requiring to refactor the entire composition. The restrictions of such a system are listed. An implementation of the model and a case study are reported as well.