Algorithms forarealisticvariantofflowshopscheduling

This paperdealswitharealisticvariantofflowshopscheduling,namelythehybridflexibleflowshop. A hybridflowshopmixesthecharacteristicsofregularflowshopsandparallelmachineproblemsby considering stageswithparallelmachinesinsteadofhavingonesinglemachineperstage.Wealsoin- vestigate theflexibleversionwherestageskippingmightoccur,i.e.,notallstagesmustbevisitedbyall jobs. Lastly,wealsoconsiderjobsequencedependentsetuptimesperstage.Theoptimizationcriterion considered ismakespanminimization.Whilemanyapproachesforhybridflowshopshavebeenproposed, hybrid flexibleflowshopshavebeenrarelystudied.Thesituationisevenworsewiththeadditionof sequence dependentsetups.Inthisstudy,weproposetwoadvancedalgorithmsthatspecificallydealwith the flexibleandsetupcharacteristicsofthisproblem.Thefirstalgorithmisadynamicdispatchingrule heuristic, andthesecondisaniteratedlocalsearchmetaheuristic.Theproposedalgorithmsareevaluated by comparisonagainstsevenotherhighperformingexistingalgorithms.Thestatisticallysoundresults support theideathattheproposedalgorithmsareverycompetitiveforthestudiedproblem.