简介:Smeconceptsusedinknowledgebasemaintenace,suchassequence,newlaw,user'srejectionandreconstructionsofaknowledgebase,arefirstintroduced,andthenaframeworkforextendedlogicprogramming(ELP)isgiven,whereanextendedlogicprogramisequivalenttoaknowledgebase.AtransitionsystemcalledR-calculusforELPisprovided.Foragivenknowledgebaseandauser'srejection,theR-calculusforELPwilldeducebestrevisionsofthebase.ThesoundnessandthecompletenessoftheR-calculusforELPareproved,andtheR-calculusforELPisimplementedinProlog.Inaddition,theresearchiscomparedwithotherrelevantwork.
简介:TheproblemofpicksequencingintherotaryrackS/Rsystem(PPS-RRS)isinvestigatedwiththeobjectiveofminimizingtheexecutiontime.TherotaryrackS/RsystemconsistsofoneS/Rmachineandmultiplelevelsofcarouselsthatcanrotateindependentlyinbi-directions.Theroutingpolicy,namelythedecisiononthestorageorretrievalsequence,dominatestheefficiencyandthethroughputforsuchS/Rsystems,duetothecomplicatedrelationshipbetweenalllevelsofcarouselsandtheS/Rmachine.ForthepurposeofoptimizingthePPS-RRS,acomputationalmodelisdevelopedintermsofexecutiontimeforpickingmultipleitemsinonetrip.CharacteristicsofthePPS-RRSareanalyzedandalocalsearchheuristicbasedonanewlyproposedneighborhoodispresented.Integratedwiththeproposedlocalsearchprocedureanewhybridgeneticalgorithmisdeveloped.Experimentalresultsdemonstratethestructurecharacteristicsofgoodsequenceandtheefficiencyandeffectivenessoftheproposedsequencingalgorithms.