Quality of Service in Web Services Discovery

The ability to discover required Web services and select the most proper one is becoming critical in Service-Oriented applications. Many techniques have been proposed to optimize the selections of Web Services by calculating quality of service (QoS). In this paper, we incorporate QoS advertisements of service providers into WSDL documents. The Quality Manager is introduced to discover Web services, collect quality ratings from users, and calculate QoS when a quality assessment is required. We calculate and compare user-concerned quality attributes using exception-based method. When all concerned quality attributes are retrieved, the ratings of web services are then calculated and the most suitable one is selected.