Efficient multi-QoS attributes negotiation for service composition in dynamically changeable environments

Service composition with Quality of Service (QoS) is widely studied nowadays and there are some approaches effective for the composition problem in ideal conditions but no feasible solution for dynamic and uncertain QoS constraints environment. Therefore, a novel service negotiation mechanism is proposed in this paper. The mechanism is composed by three parts for negotiation: model, protocol and strategy. The model creates a new hierarchy architecture based on negotiation agent to improve the efficiency of tasks execution of each agent. The protocol dynamically updates solution search line, on which proposals are made by trading partners, and approximate Pareto-optimal solution is achieved through the neutral mediator. The strategy enhances the negotiation sensibility by considering three factors: time, opponent actions and global negotiation states. The negotiation process is coordinated by Manger Agent (MA), which provides suggestions for the next negotiation round based on the overall negotiation context. Experimental results show that the proposed approach is effective to find a feasible solution in the dynamically changeable composition environment.