Schedulingunrelated parallel machinesto minimizetotal weightedtardiness

This paperaddresses thebatchscheduling problem ofunrelated parallel machines attempting tominimize thetotal weighted tardiness. Identical orsimilar jobsare typically processed inbatches todecrease setupand/or processing times. Localdispatching rules suchastheearliest weighted duedate, theshortest weighted processing time, and theearliest weighted duedatewithaprocess utilization spread aretailored tothebatchscheduling requirements. Basedonthe features ofbatchscheduling, a two-level batchscheduling frameworkissuggested. Existing heuristics, whichshow excellent performance intermsoftotal weighted tardiness for thesingle machine scheduling, suchasthemodified earliest due dateruleandthemodified costovertimerule, areextended for theproblem. The simulated annealing algorithm as a meta-heuristic isalsopresented toobtainnearoptimal solutions. Theproposed heuristics arecomparedthrough computational experiments withdatafromthedicing process ofacompound semiconductor manufacturing facility IndexTerms-Scheduling, parallel machine, heuristics, tardiness