When an individual is closed to the optimal particle,its velocity will approximate to zero.This is the main reason why particle swarm optimization(PSO) algorithm is prone to trap into local minima.A new improved particle swarm optimization(IPSO) is proposed,in which is guaranteed to converge to the global optimization solution with probability one. During the running time,the mutation probability for the current particle is determined by the variance of the individual's concentration and convergence functio...