“…The problem has been formulated using different modelling techniques. A number of approaches describe the problem with mixed integer linear programming (Anwar and Nagi 1998;Bilge and Ulusoy 1995;Caumond et al 2009;Khayat, Langevin, and Riopel 2006;Lacomme, Moukrim, and Tchernev 2005;Nishi, Hiranaka, and Grossmann 2011;Raman, Talbot, and Rachamadgu 1986;Suri and Desiraju 1997;Zheng, Xiao, and Seo 2014), while a few works have considered PN (Lee and DiCesare 1994a;Raju and Chetty 1993;Sun, Cheng, and Fu 1994), and disjunctive graph modelling (Lacomme, Larabi, and Tchernev 2013). The other works whose methods are based on metaheuristics like genetic (Abdelmaguid et al 2004;Chaudhry, Mahmood, and Shami 2011;Jerald et al 2006;Reddy and Rao 2006;Ulusoy, Sivrikaya-Serifoglu, and Bilge 1997), differential evolution (Kumar, Janardhana, and Rao 2011), and simulated annealing (Deroussi, Gourgand, and Tchernev 2008), use a solution vector with fixed-length strings to represent a schedule called chromosome.…”