Web Service Top-K Query

Web service plays an important role in Service-Oriented-Computing model, it is used as a fundamental component in semantic web construction, and it is center part of service oriented architecture. As the number of services on the internet becomes larger and larger, automatic or semiautomatic discovery of appropriate web service has become an indispensable segment in service oriented computing. Only in the way you find the suitable service and then to do composition or integration you can implemente the requirements of customers or achieve the goal. Besides the functional demands of services, the qualities of services are appreciated. In the keyword query of services, there are many services satisfying the funtional demands but the nonfunctional requrements, like qualities, which can be used as service selection criteria.In the view of the problems described above, this paper delve into the top-k query study of web services. We consider the qualities of services as an important aspect. It is a focus of web discovery study area. Web service description language file is used to describe the interface of services, based on XML grammar. It has special semantic and structural characters, but xml query skills can also be used in the query of web services. We can transform the keyword query into a tree-like structural query, whose root is "operation", to meet the need of functions. The invocation of web servies are on the basis of the Internet, we can find that the quality of service in the network transfering and distributed system determines the performance, so the qualities of web services are also significant. Among the services meet the function nees, we will return the services which have better qualities. In the paper, we give the data normalization, define the dominance relationship between services, improve the traditional method of top-k query to propose StopLine algorithm, which converge faster. In the experiment, we implement all the query methods and compare them with each other and give the sketch map of query time as the result.