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M ost o f the research on jo b shop scheduling problem are concerned w ith m inim ization o f a single objective. How ever, the real
w orld applications o f jo b shop scheduling problem s are involved
in optim izing m ultiple objectives. T herefore, in recent years ant
colony optim ization algorithm s have been proposed to solve jo b
shop scheduling problem s w ith m ultiple objectives. In this paper,
som e recent m ulti-objective ant colony optim ization algorithm s are
review ed and are applied to the jo b shop scheduling problem by
considering tw o, three and four objectives. A lso in this study, four
criteria: m akespan, m ean flow tim e, m ean tardiness and m ean m achine idle tim e are considered fo r sim ultaneous optim ization. Two
types o f m odels are used by changing the num ber o f ants in a
colony and each m ulti-objective ant colony optim ization algorithm
is applied to sixteen benchm ark problem instances o f up to 2 0 jo b s
x 5 m achines, for evaluating the perform ances o f these algorithm s.
A detailed analysis is perform ed using the perform ance indicators,
and the experim ental results have show n that the perform ance o f
som e m ulti-objective ant colony optim ization algorithm s depend
on the num ber o f objectives and the num ber o f ants.
