Research On Web Services Composition Based On Multiobjective Optimization

Web Service extracts the advantage of distributed computation,Grid computation and XML,and solves the problems of heterogeneous distributed computation and data reuse. Web Service has the characters of inter-operation,multi-platform and loose coupling,so it becomes the leading development trend of WWW. But single Web Service has limited function,service increment and service reuse can be obtained only through combining multiple Web Services. Thus, the potential of Web Service can be brought into play. Web services are gaining acceptance as a standards-based approach for integrating loosely coupled services often distributed over a network.How to create robust service compositions becomes the next step work in web services and has attracted a lot of researches. At the same time, web services selection supporting global QoS constraints plays an important role in web services composition. Since web services with the same functions and different QoS are increasing with the proliferation of web services, it is needed to select the best composite plan from numerous plans in order to maximize satisfaction of user and satisfy the consumers'global QoS constraints. The researches about practicability, effectivity, stability and adaptivecapability of selection mechanism have gained considerable momentums.In order to resolve services selection with the global QoS constrain This paper presents an algorithm to resolve dynamic Web services selection with QoS global optimal in Web services composition. The essence of the algorithm is that the problem of dynamic Web Service selection with QoS global optimal is transformed into a multi—objective services composition optimization with QoS constraints. The theory of intelligent optimization of multi-objective genetic algorithm is utifized to produce a set of optimal Pareto services composition process with constraint principle by means of optimizing various objective functions simultaneously. The oretical analysis and experimental results indicate the feasibility and efficiency of this algorithm.