Adaptive QoS Based Web Service Composition Research

SoC (service of Computing) service oriented computing rapidly changing software developmentindustry, the WebService is the realization of a technology, SoC is one of the most important characteristicis, provides a flexible framework to reuse existing software and combined services, using a number ofexisting independent portfolio of services to meet the user demand for complex tasks. In the service of thecombination process is the most important point for service combination results meet the user’s QoS(quality of service).QoS adaptive service composition is web service combination of QoS to meet the needs of users.Considering the service environment, how the dynamic environment to select service composition is a verychallenging problem, this problem include three points:1in the dynamic environment, a service node indexis determined at run-time,2in dynamic environment, each call to the service node effect should not be thesame, how the dynamic environment to consider the service node QoS conditions on service results of theinfluence of floating, this is a relatively difficult problem.3in the dynamic environment of how to use therelated algorithms to calculate the QoS optimal portfolio of services, is a core problem, and the algorithmcomplexity is relatively low. The three problem is solved by QoS adaptive service combination most majorproblem.Workflow is a part or the whole business process in computer application environment of automation.Workflow has21kinds of pattern, for example: sequential, parallel split, synchronization etc.These modelsare sufficient to describe the general service nodes and service nodes of the business relationship betweenthe. To work as a model for the study of QoS conditions, is very scientific.Based on the SPFA algorithm, the study of adaptive QoS service combination algorithm, analysis ofthe impact of QoS in all aspects of factors, objectively using the algebraic form give evaluation, as theresearch model of workflow, workflow model analysis of the working principle, the QoS algebra evaluationapplied to workflow model, finally using SPFA algorithm based on workflow model service composition,and the algorithm to optimization, the optimization applies only to web service composition process.