IntroductionMeta heuristics algorithms are usually used for the problems that are based on the behavior of real creatures. They basically try to combine basic heuristic methods in higher level frameworks aimed at efficiently and effectively exploring a search space. This class of algorithms includes Genetic Algorithms (GA), Iterated Local Search (ILS), Simulated Annealing (SA), Tabu Search (TS), Ant Colony Optimization (ACO), etc. ACO is a meta-heuristic approach proposed by Dorigo et al. (1991). The basic algorithm of ACO is Ant System (AS).