Service Adaptation with Probabilistic Partial Models

1 Singapore University of Technology and Design 2 Nanyang Technological University 3 The University of Auckland 4 National University of Singapore Abstract. Web service composition makes use of existing Web services to build complex business processes. Non-functional requirements are crucial for the Web service composition. In order to satisfy non-functional requirements when composing a Web service, one needs to rely on the estimated quality of the component services. However, estimation is seldom accurate especially in the dynamic environment. Hence, we propose a framework, ADFLOW, to monitor and adapt the workflow of the Web service composition when necessary to maximize its ability to satisfy the non-functional requirements automatically. To reduce the monitoring overhead, ADFLOW relies on asynchronous monitoring. ADFLOW has been implemented and the evaluation has shown the effectiveness and efficiency of our approach. Given a composite service, ADFLOW achieves 25% – 32% of average improvement in the conformance of non-functional requirements, and only incurs 1% – 3% of overhead with respect to the execution time.