Research Of Removing Redundant Based On Skyline In Web Service Composition

In recent years,with the rapid development of Internet technology,more and more Web services are available.However,the functions of a single Web service are limited,and people's requirements for Web services are constantly increasing.Users need more complex and more functional Web services.Web services composition combine services with different functions on the network to meet the needs of users.How to search for a suitable service from a large number of services and obtain a combination of specific inputs and outputs is an NP-hard problem.Therefore,how to choose a method to find a suitable Web service composition is a problem that needs to be solved urgently.In order to solve the Web service composition problem,this paper chooses the planning graph algorithm to achieve the semantic composition of Web services,make improvements on this basis,and choose services with better QoS.There are two ways to judge the QoS here: a single critetion and a multiple criteria.To solve the problem of low efficiency of service selection under large-scale service,skyline algorithm can filter web services dominated by other services and delete useless services.The redundant services cause additional time and costs.To remove redundant services,a redundant removal algorithm is proposed to remove redundant services in the backward search phase of the planning graph.On this basis,a method of removing redundant based on Skyline in Web service composition is proposed.The model is divided into three stages.First,the Skyline operator is used to filter the service repository and retain services with better QoS,and deleted a large number of dominated services in the repository.After that,a set of Skyline services expanded forward to find candidate services that meet the needs of users.Finally,starting from the output parameters requested by the user,a reverse search is carried out,and redundant services are deleted using the remove redundant method at the same time,to obtain a non-redundant Web service composition method.The experimental analysis and verification using data sets show that,the selection process in planning graph,Skyline method and the remove redundant method have the effect of optimizing the combined results.Compared with the original planning graph algorithm,the method of removing redundant based on Skyline in Web service composition algorithm eliminates a large number of redundant services,can obtain a better QoS solution,and maintain a short execution time.