An Ordered Flow Shop Sequeneing Problem With TWK Type Due Dates and Total Tardiness Criterion

A static n job m-machine ordered flow shop problem is considered.Prior research with such a problem has dealt with the makespanand the mean flow criterion. This paper considers minimizationof total tardiness as the objective. Due dates for all jobsare considered to be proportional to the sum of the processingtimes for each individual job. It is shown that by simply arrangingjobs according to an ascending order of processing time (i.e.by the SPT rule) one can obtain a minimum tardiness sequence.