1. Introduction
Ant Colony Optimization Algorithm (ACO) is a novel bionic algorithm that was presented by Italy scholar M. Dorigo et al. in the 1990s [1], [2], [3], [4]. It has proved to bring many advantages, such as distributed calculation, information positive feedback, and easy combining with other algorithms and so on. Nowadays, it has been applied to classic combinatorial optimization problems extensively, for example, TSP [5], QAP [6] and so on. But the basic ACO has some disadvantages such as longer convergent time and easy falling in local best.