Usability of Web services

This paper is concerned with the application of Web services to distributed, cross-organizational business processes. Web services provide a platform independent concept of components and composition. Thus, they seem to be a proper technology to cover the heterogeneous structures within distributed business processes. Although the technological basis is given, there are a lot of open questions, such as whether Web services fit together in such a way that the composition yields a deadlock-free system - the question of compatibility; whether one Web service can be exchanged by another within a composed system without running into problems - the question of equivalence; and whether we can reason about the quality of one given Web service without considering the environment it is used in. In this paper, we present the notion of usability - our quality criterion of a Web service. This criterion is intuitive and can be easily proven locally. Moreover, this notion allows to answer the other questions.