Quality of Servicebased Web Services Optimal Selection Algorithm and Its Simulation

Abstract:

The paper presents a quality of servicebased(QoS) Web services optimal selection method by multiobjective genetic algorithm by taking three aspects of constrains in services selection process into consideration, such as control structure within a composition plan, relationship between concrete services, and tradeoff among multiple QoS indexes. Moreover, a layered services selection model is constructed for formalizing optimal services selection problem,and a multiobjective genetic algorithm is first adopted. In particular,a chromosome coding method is first designed to represent a feasible services selection solution, and then genetic operators and strategies are developed to maintain diversity of population and also avoid getting trapped in local optima. Finally, experimental results show that this algorithm can generate a set of nondominated Pareto optimal solutions which satisfy to users’ QoS requirements within a finite number of evolving generation.The adopted genetic strategies have good effect on maintaining diversity of population and increasing convergence of algorithm.

Key words:Web services selection; quality of service; multiobjective genetic algorithm