Efficient web services discovery and composition

As an emerging cross discipline area for distributed computing, Service-Oriented Computing (SOC) paradigm promises to bridge the gap between Business Services and IT Services, enable technology to help people perform business processes more efficiently and effectively, and enable businesses and organizations to collaborate globally through standard services. With the rapid development and popularity of Internet and e-commerce, business organizations are investigating ways to expose their current software components into web services so as to make use of distributed service computing resources. Business organizations are also investigating ways on how to incorporate services running on different platforms and hosted by service providers outside of their boundaries into more complex, orchestrated services.\ud In this thesis, we investigate the problem of efficient web services discovery and composition in service oriented environments. Firstly, we present an efficient IR-Style mechanism for discovering and ranking web services automatically, given a textual description of desired services. We introduce the notion of preference degree for a web service, and suggest relevance and importance as two desired properties for measuring its preference degree. Also, various algorithms are given to obtain service relevance and importance. The key part for computing service importance is a new schema tree matching algorithm, which catches not only structures, but even better semantic information of schemas defined in web services. Moreover, we develop an approach to identify associations between web-service operations based on service operations matching. This approach uses the concept of attribute closure to obtain sets of operations. Each set is composed of associated web-service operations. Experimental results show the proposed IR-style search strategy is efficient and\ud practical