Specifying Data-Flow Requirements for the Automated Composition of Web Services

One of the fundamental Ideas of Weh services and service oriented architecture is the possibility to develop new applications by composing existing services that are available on the Web. Several approaches have been proposed to tackle the problem of Web service composition, but little effort has been devoted so far to the problem of modeling the requirements of the composition. However, it is clear that the possibility to express requirements specifying complex interactions patterns among the component services is an essential step to cope with a wide range of composition problems. In this paper we present a new model which addresses one of the key aspects of composition requirements, namely the dataflow among the component services. We develop graphical notations and a formal theory for the new model and we integrate it within an existing automated composition framework