Trust-Oriented Workflow Scheduling With Multiple Temporal Constraints In Cloud Computing

The presence of uncertainty and dynamic charateristics of cloud services and the existence of false or fraudulent services in the cloud environment, making it difficult for users to obtain desired services. Therefore, the introduction of trust evaluation mechanism in cloud is very important. In this thesis, trust-oriented workflow scheduling in cloud computing with multiple temporal constraints which considers trust of services, setup time required for service execution and deadline of workflow to minimize total cost trust ratio is full of theoretical significance and practical value.According to the characteristics of the problem, the corresponding constraints and the basic properties, a mathematical model is established for the considered problem and behavior-based trust model is established for assessing the trust of services. Iterative adjustment heuristic(IAH) is proposed acording to the optimization objective, which includes three initial solution gener-ation strategies (EFTF,MCTRF,MTTF),two candiate solution set generation methods(TD,CI) and adjustment(Max-Min based). Different strategies in there parts of IAH make up six heuris-tics:EFTA?MTTA?MCT?EFCA?MTCA?MCCA.To test the efficiency and effectiveness of the proposed algorithm, three initial solution methods are carried to get the best initial solution generation strategy, parameters of IAH are also test and analysed. Three algorithms (MCTA, EFTA and MTTA) in IAH are compared with PCP and EFIH. Experimental results show that MTTA outperforms the other four algorithms.