“…Li et al (2013a) implemented discrete PSO for the train assembly. Besides those popular algorithms, researchers also implemented relatively new algorithms such as the imperialist algorithm (Zhou et al , 2013), the immune algorithm (Lu et al , 2013), shuffled frog leaping (Guo et al , 2015), breakout local search (Ghandi and Masehian, 2015), the firefly algorithm (Li et al , 2015a) and harmony search (Li et al , 2015b; Wang et al , 2013).…”