The Research And Implementation Of Combinatorial Optimization Algorithm In Guaranteeing Web Service’s QoS

Service-Oriented Architecture is the main software architecture frameworkwhich is developed by the way of computation oriented services, based on thecomputer network and comunication technology, provides the framework forimplementing interaction among across-platform network applications such ase-government affairs, e-business and so on. Web service is a software system thatsupports the interoperability from devices to devices through network, it offers astandardized implementation for SOA: resource sharing and cooperative work innetwork environment; The web service framework W3C work out is made of a seriesof standards which is based on three protocols: SOAP, WSDL, UDDI. Web servicecomposition is services choreography, actually, it composite the WSDL by businessprocess execution language. Quality of service includes lots of non-functionalattributions of web service such as availability, price. With the increasing of serviceshaving similar functions, quality of these services generally differs, as the underlyingfunction, service selection and sorting based on QoS have become common methodsof compositing service and draw attention of academic community deeply.Depending on a simple booking online case, this paper completes as follows:Firstly, I analyses the requirement according object-oriented thinking and formsthe idea of building and developing application, then develops correspondingapplication module, on the base of which I encapsulate the modules into services.Secondly, try to reseach documents about WS-BPEL and grasp how toimplement the interaction among web services and process choreography byWS-BPEL; Seek to build WS-BPEL models in terms of developed services, deploythem into web container, execute them, at the same time, develop the client. At last, try to find a method which could descripe and restore QoS, explore analgorithm to select the best service according to the QoS of web service and User’sQoS demand; Then, we enlarge the quantity of services, extend network nodes,establish the parameters system of QoS and assign distinct QoS values to each service;By this means, the system can assess different services with similar functions andinterfaces by users’ QoS demand and QoS parameters system of services, then selectthe best one through some algorithms and implement service composition.