“…Since its invention, PSO has been applied with success on various COPs such as, the unit commitment problem 31 , the traveling salesman problem 32 , the task assignment problem 33 , an optimal operational path finding for automated drilling operations 34 , a multi-objective order planning production problem in steel sheets manufacturing 35 , scheduling problems involving duedates 29 , the shortest path problem 36 , etc. Recently, its application has been extended on scheduling problems such as, flow-shop scheduling problems [37][38][39][40][41] , the singlemachine total weighting tardiness problem 27,42 , the single machine scheduling problem with periodic maintenance 28 , the two-stage assembly-scheduling problem 43 , and job-shop scheduling problems 44,45 . Assuming the problem of minimizing a real-valued function ƒ(x), x∈Ω⊂ℜ D (Ω is assumed to be the feasible search space of the problem), PSO utilizes a set (called swarm) of Ns particles as a population to search Ω toward the global optimal solution.…”