Research On Web Service Composition And Validation Based On Qos

With the rapid development of Web Service technology and application, more and more Web Services are deployed on the internet. So the quantity of similar Services increases rapidly. Single-function Web service has been unable to meet the needs of complex applications. It is necessary to composite atom service in order to form powerful compositional service to handlecomplex requirements.Service selection is the most important part in Web Services composition. There are a lot of services with similar function that can be selected.However, the non-function attributes ofeach service, such as service execution time, price and reliability, etc, is not the same. These existing services can be composed many compositeservice with the same function but with different QoS. The users will have troublein selecting a choosing composition planamong those candidate plans which satisfy users’QoS requirements. How to choose optimal composite plan to meet users QoS constrained belongs to optimization problem. This paper proposed the improved genetic algorithm to handle QoS-aware services composition among multiple paths problem.The algorithm from many aspects, such as coding schema, population initialization, fitness function, crossover/mutation strategy, evolution strategy and so on. These improvements make algorithm has better convergence speed and search ability.Due to the complex requirements of Web services characteristics, it is inevitable that some errors will occur when Web services arecomposited.This paper analyzed the related work of Web service composition validation, and introduced the classification of Web service consistency. And also, a service composition QoS consistency verification algorithm was presented. The algorithm can ensure the correctness of service composition.