An anticipativeschedulingapproachwithcontrollableprocessingtimes

In practice,machineschedulesareusuallysubjecttodisruptionswhichhavetoberepairedbyreactive schedulingdecisions.Themostpopularpredictiveapproachinprojectmanagementandmachine schedulingliteratureistoleaveidletimes(timebuffers)inschedulesincopingwithdisruptions,i.e.the resources willbeunder-utilized.Therefore,preparinginitialschedulesbyconsideringpossible disruption timesalongwithreschedulingobjectivesiscriticalfortheperformanceofrescheduling decisions.Inthispaper,weshowthatiftheprocessingtimesarecontrollablethenananticipative approach canbeusedtoformaninitialschedulesothatthelimitedcapacityoftheproductionresources are utilizedmoreeffectively.Toillustratetheanticipativeschedulingidea,weconsideranon-identical parallel machiningenvironment,whereprocessingtimescanbecontrolledatacertaincompression cost. Whenthereisadisruptionduringtheexecutionoftheinitialschedule,amatch-uptimestrategyis utilizedsuchthatarepairedschedulehastocatch-upinitialscheduleatsomepointinfuture.This requireschangingmachine–jobassignmentsandprocessingtimesfortherestoftheschedulewhich impliesincreasedmanufacturingcosts.Weshowthatmakinganticipativejobsequencingdecisions, based onfailureandrepairtimedistributionsandflexibilityofjobs,onecanrepairschedulesby incurringlessmanufacturingcost.Ourcomputationalresultsshowthatthematch-uptimestrategyis very sensitivetoinitialscheduleandtheproposedanticipativeschedulingalgorithmcanbeveryhelpful to reducereschedulingcosts.