Trust constrained workflow scheduling in cloud computing

In cloud environments, trust is necessary because services have the characteristics of uncertainty, dynamic, false or fraudulent which usually make users difficult to obtain desired services. In this paper, we consider trust-oriented workflow scheduling with temporal constraints including service setup times and workflow deadlines. The considered problem is mathematically modeled. A behavior-based trust model is established to assess trusts of services. An iterative adjustment heuristic framework is proposed which consists of initial solution construction, solution sets generation and adjustment. Three heuristic algorithms are developed and compared with the best existing methods for similar workflow scheduling problems. Experimental results demonstrate effectiveness of the proposal.