Service Composition Optimization Based On QoS In The Internet Of Things Environment

In the Internet of Things environment,large-scale service composition has always been a Nondeterministic Polynomially problem.At present,a large number of studies directly use heuristic algorithms for service composition,and this method solves the problem to a certain extent.However,with the increasing size of the service scale and the increasing disparity in the quality of service,the massive scale of service composition will seriously affect the search efficiency of the heuristic algorithm,resulting in low service composition efficiency and quality.The thesis respectively proposes service composition methods based on service domination and cumulative aggregate Qo S to improve service composition efficiency and service composition quality,and conducts theoretical derivation and experimental analysis on these two methods.The main research work of the thesis includes:1.Aiming at the problems of low service composition efficiency and reduced service composition quality caused by the large scale of service composition in the Internet of Things environment,this thesis proposes a service composition method based on service domination.The method is based on service instances with different Qo S in the abstract service,introduces the concept of service domination,uses the workflow optimization algorithm based on service domination to reduce the service composition scale,constructs the Qo S objective function of the composite service according to the Qo S model,and finally completes the instantiation of the service composition through the heuristic algorithm.Theoretical derivation and experimental results show that compared with the traditional service composition method,this method can effectively improve the efficiency and quality of service composition.2.Aiming at the specific service Qo S such as price and reputation,combined with the Qo S aggregation rules of composite service,this thesis introduces the concept of cumulative aggregation Qo S,and proposes a service composition method of cumulative aggregation Qo S.This method transforms the service composition problem into the service instance optimization in the abstract service,which simplifies the solution of service composition problem in the Internet of things environment.The effectiveness of the method is proved by theoretical derivation.On this basis,the residual energy and energy consumption of intelligent terminal devices are abstracted as Qo S attributes of services,and an energy balanced service composition method based on cumulative aggregation Qo S is proposed.Through experimental comparison with other methods,the results show that this method can provide low-energy composite services and ensure the life cycle and stability of the whole service composition workflow.Research work shows that compared with traditional service composition methods,the service composition method based on service dominance and the service composition method of cumulative aggregation Qo S can further effectively solve the problem of mass-scale service composition in the Internet of Things environment.