On Utilizing Web Service Equivalence for Supporting the Composition Life Cycle

Deciding on web service equivalence in process-aware service compositions is a crucial challenge throughout the composition life cycle. Restricting such decisions to (activity) label equivalence, however, is not sufficient for many practical applications: if two activities and web services respectively have equivalent labels, does this necessarily mean they are equivalent as well? In many scenarios (e.g., evolution of a composition schema or mining of completed composition instances) other factors may play an important role as well. Examples include context information (e.g., input and output messages) and information on the position of web services within compositions. In this paper, we introduce the whole composition life cycle and discuss specific requirements for web service equivalence along its different phases. We define adequate equivalence notions for the design, execution, analysis, and evolution of service compositions. Main focus is put on attribute and position equivalence. Altogether this paper shall contribute a new understanding and treatment of equivalence notions in service compositions.