Quality-Driven Web Service Composition for Ubiquitous Computing Environment

Web services technology is increasingly being considered as a promising solution to support the interoperability in ubiquitous computing environments. As many Web services with similar functionality are available on the Web, quality issues become important to distinguish a service from the competing services. In this paper, we propose a quality-driven Web service composition methodology for ubiquitous computing environment. Our methodology evaluates the quality of Web services in three dimensions- quality of services, quality of contexts and quality of devices. We also introduce EWC (Event-driven Web services Composer) as a comprehensive tool to support our methodology. Our EWC 1) automatically prioritizes Web service candidates based on their quality in services, contexts and devices, 2) selects the optimal web service for a given condition, 3) executes the optimal web services, and 4) monitors and dynamically reconfigures the web services, if the deployed web services fail to meet the given quality criteria. We show how EWC efficiently provides personalized and high-quality services through a "diabetes monitor" example.