The Cloud Service Evaluation Based On QoS In Cloud Computing Environment

Cloud computing is a computing model that provides users with the resources of storage,calculating,and software services by the Internet.Users don't have to worry about the resources of hardware and software.In the computing model of cloud services,cloud services are characterized by large scale,high complexity and the cloud resources of dynamic change.Traditional assessment techniques are difficult to carry out authority and accurate assessments for cloud services.The existing evaluation models and system frameworks have been studied and analyzed in this paper.The QoS is the major attributes that evaluate cloud services for users' fitness.Now,the most urgent task is to make an objective assessment for the QoS and credibility of cloud services,because the higher accuracy of evaluation means that the cloud services that providers provide are more suitable for users' needs.This thesis researches and analyzes the problem that how users maximize the resources and data to meet their needs.This thesis proposes two kinds of methods of cloud services evaluation based on QoS,and proves the advantages of two kinds of algorithms by policy experiments.The following are the main topics of this thesis:1.For the problem of cloud services evaluation,this thesis has constructed a comprehensive evaluation index system of cloud services of Qo S with cloud resource characteristics and network service characteristics.Because the evaluation indexs are related to each other and the floating of the evaluation indexs are influential in the final evaluation of cloud service QoS,this thesis raises a service Qo S evaluation algorithm of principal component analysis.The method can make the result of the cloud service evaluation more accurate.2.For the problem that the existing methods are difficult to quantify the natural language,this thesis presents a cloud service evaluation algorithm based on fuzzy analytic hierarchy process.On the basis of feedbacks of service requesters and service level agreements,this thesis has constructed a evaluation system of cloud service nonfunctional QoS with performance,service protocols,service costs,security,and reputation.This method adopts natural language evaluation type by triangular fuzzy number to make the index weights more accurate.Then,the result of cloud service evaluation value is more objective and accurate.