Research On QoS Modeling And Analysis Of SaaS-Oriented In Cloud Computing

With the developping of Cloud computing, which gradually changes the way of using services andresources, more and more research focu on this field. At present, Amazon, IBM, Google, Sun,Microsoft and the other international large IT firms have been set up and provided somel kinds ofcloud computing services. According to the national institute of standards and technology (NIST),thecurrent cloud computing services is divided into three levels as Infrastructure serve IaaS(Infrastructure-As-A-Service), Platform Service PaaS (Platform-As-A-Service), Software ServiceSaaS(Software-As-A-Service). SaaS is a new service mode which bases on the cloud service.QoS (Quality of Service) is Quality of Service. Regarding to the network business, service qualityincluding the transmission bandwidth, transmit delay, data packet loss rate, etc. The QoS of webservices is refers to the web service QoS non-functional attributes such as performance, reliability,availability and safety. Researchers domestic and overseas are trying to consider QoS from sevealaspects, such as dynamic services selection and service composition. In the multi-layer environmentof clouds computing, a single Saas service’s QoS are more complex..The main contributions of this thesis are as follows:1. Compare the traditional web services and SaaS in cloud computing environment. Considering theplatform dependencies and Multitenancy of SaaS, giving the new definitions of the QoSattributes. Meanwhile, in order to support the service modeling, giving the abstract of the QoSattributes, and the evaluation method and every QoS attribute weight gain method.2. In order to support QoS modeling and analysis of SaaS. This paper expand the abstract QoSattributes into the UML sequence diagram of SaaS, and consider of the service composition, italso gives the model of activities in BPEL.Finally, in order to support Formal analysis andverification, this paper gives the formal definition of SD.3. Through a travel booking system in cloud computing. verify the validity and feasibility of theabove process, and according to the existing research, give the QoS verification and analysis ofthe system.