QoS全局最优的Web服务选择是NP完全问题.针对现有解决方案的不足,提出了一种改进的离散粒子群算法.该算法首先根据问题模型重新定义了粒子群算法中的位置、速度和算子操作,然后对最优粒子进行非均衡变异,并设计了非均衡变异概率函数,同时在速度和位置更新中分别采用自适应权重调整机制和局部适应优先策略.通过实验仿真,与他人工作对比结果表明,提出的算法在降低服务选择时间的同时,提高了服务选择的质量.
Global QoS optimal Web services selection is a NP complete problem.In order to overcome slow convergence of existing schemes,an improved discrete particle swarm optimization,called Discrete Particle Swarm Optimization with Non-Uniform Mutation Algorithm(short for DPSONUMA),is proposed.In DPSONUMA,we firstly redefine the particle position,velocity and update operations to make the algorithm more suitable for this problem.Then the best particle is introduced a mutation ability,and a mutation probability function is also designed.And weight factors of velocity will adaptively change according to the fitness values,which can improve convergence.In addition,a local fit first strategy is introduced,which lead to both quicker converge and better results.Experimental results show DPSONUMA costs less time but higher quality components are obtained for composite web services.