Total flowtimeminimizationinaflowshopsequence-dependentgroup scheduling problem

We havedevelopedamathematicalprogrammingmodelforminimizingtotalflowtimeoftheflowshop sequence dependentgroupscheduling(FSDGS)problem,typicallyclassifiedas Fm|fmls, Splk, prmu| Cj. As the problemisshowntobestronglyNP-hard,atabusearch(TS)algorithmaswellasahybridantcolony optimization (HACO)algorithmhavebeendevelopedtoheuristicallysolvetheproblem.Alowerbounding (LB) methodbasedontheBranch-and-Pricealgorithmisalsodevelopedtoevaluatethequalityofthe metaheuristic algorithms.Inordertocomparetheperformanceofmetaheuristicalgorithms,randomtest problems, ranginginsizefromsmall,medium,tolargearecreatedandsolvedbyboththeTSandthe HACO algorithms.AcomparisonshowsthattheHACOalgorithmhasabetterperformancethantheTS algorithm. TheresultsoftheheuristicalgorithmsarealsocomparedwiththeresultsoftheLBmethodto evaluate thequalityofthesolutions.TheLBmethodpresentedinthispapercanbegeneralizedtosolve the FSDGSproblemwithotherobjectivefunctions.