y.Intheimprovedsystem,regionaldistributioncenterscanmakeadecisiontoreducetherelatedcosts—orderonlytheamountavailableorpostponetheordering.Basedonexperiments,theproposedsystemoutperformsheclassicalDRP.AnotherrelevantresearchworkbelongstoDeKokandFransoo().Theauthorsproposedtheso-calledSynchronizedBasedStock(SBS)policyandcompareditsperformancetotheLP-basedsystemunderthebackloggingmodel.TheSBS,whichusesthebase-stock-policyconcept,raisestheinventorypositiontomeettheadjustabletargetlevelineveryinventoryreview.ItisconcludedthattheSBSoutperformstheLP-basedsystemconsiderablybecauseitusesmoresophisticatedorderingmethodandrationingrule.Ganeshanetal.()studiedtwoinventorycontrolsystems,namely,DRPandReorderPointsystemsinafour-echelonnetwork.TheDRPsystemreferstoacalculationofupstreamreorderquantitiesandreorderintervalsbyaggregatingaaro,I.,Pontrandolfo,P.,.Inventorymanagementinsupplychains:Areinforc