The Selection And Composition Of Web Service Based On QoS

With the development of Internet and Web technologies, traditional distributed computing technologies have not been suitable for the Web application environment. Therefore, Web services come forth that become the focus in the area of industry and academia with the advantages, such as self-contained, modularization, loose coupling and standardization. Nowadays, compositing previous available Web services into incremental Web services with more powerful functions has been a new hotspot. And to select Web services during the process of compositing them is a chief task..The number of Web services is dramatically increasing with the popularity of Web services technology,Web services providing the same or similar function will mushroom substantially.So,It is needed to think about some non-functional attributes such as price,response time,reputation for those Web services with the same function when selecting them,namely QoS (Quality of Service).So QoS becomes the important criterion of Web services selection.The paper researchs the following aspects on the basis of analyzing related status quo .1. The research about the extension mechanism of Web services description Web services description language (WSDL) and Web services registration and discovery don't provide support for descripting QoS attributes currently,The paper makes Web services selection based on QoS information become possible by extending QoS information in them respectively.)2. The research about QoS-based Web services selection algorithms The paper views Web services selection problem in Web services composition as combinational optimization problem and designs QoS- globally optimal model which can satisfy the user's constrains.,Then adopts simulated annealing algorithm and genetic algorithm to resolve respectively, At last plentiful experiments are made to compare this two algorithms.3.The research about Web services composition based on UML The paper detailedly introduces the steps and processes using UML to composite Web services by a travel service as example,Then makes evaluation to this method.4. Designs and realizes a QoS-based Web services selection antetype system.