Towards Modeling Web Service Composition in UML

This paper focuses on how to model and build composite web ser- vices from already existing services. We build on the experience in workflow modeling and see if the principles are applicable to the web service domain. It is revealed that there are particular needs for web services that are not fully captured by traditional workflow modeling. UML is used as the modeling tool for capturing these needs. If there is no direct support for the need, we propose a UML extension. Many of the proposed extensions are shown within a com- posite web service model that represents a gas dispersion emergency case.