“…The second group contains all methods that find an approximate solution. The methods in this group are based on different strategies such as probabilistic, greedy, and soft computing such as genetic, ant colony and swarm (Nazmul et al, 2007;Chengwei and Jianhua, 2009;Li and Wang, 2010;Li and Wang, 2009;Chan et al, 2008;Clerc and Kennedy, 2002;Li and Tompa, 2006;Sze and Zhao, 2006). All these techniques depend on finding local optimal solution.…”