“…This Branch and Bound approach solved some of these instances in more than 7 days. Because this problem is NP-hard, many researchers used a wide variety of metaheuristics to solve this problem, such as a genetic algorithm (Franca et al, 2001;Sioud et al, 2009), a memetic algorithm (Armentano & Mazzini, 2000;Franca et al, 2001;Rubin & Ragatz, 1995), a simulated annealing (Tan & Narasimhan, 1997), a GRASP (Gupta & Smith, 2006), an ant colonies optimization (ACO) (Gagné et al, 2002;Liao & Juan, 2007) and a Tabu/VNS (Gagné et al, 2005). Heuristics such as Random Start Pairwise Interchange (RSPI) (Rubin & Ragatz, 1995) and Apparent Tardiness Cost with Setups (ATCS) (Lee et al, 1997) have also been proposed for solving this problem.…”