c ○ 2001 Kluwer Academic Publishers. Manufactured in The Ne(18)

Abstract. A data cube is a popular organization for summary data. A cube is simply a multidimensional structure that contains in each cell an aggregate value, i.e., the result of applying an aggregate function to an underlying relation. In practical situat

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densitydistributionofthevaluesischosentofollowthefollowingdistributions:Normalwithmean20andvariance400(AandB),Normalwithmean15andvariance25(C),andUniformwithmean10(D).WealsogeneratethecellsvaluestofollowEq.(6),wherethefactorsaredistributedasfollows.EffAisdistributedasU(10,40),similarly,EffBasU(10,20),EffCasU(1,100),EffDasU(40,80).Wealsogeneratetwo-factoreffectEffCDasN(20,102).ThisleadstotheloglinearmodelonEq.(7)beingthebest tforthecells.Itisimportanttopointoutthatthisispreciselythemodelwegetwhenweapply

pressionusingthesynthesizeddataset,withα=0.15,β=0.2,γ=0.4,MINTUPLE=

500.Figure7.Rangequeriesoverthesyntheticdataset.Thegraphshowsthetimetoexecutethequeryinsecondsversustheselectivityofthequeryasapercentageofthenumberofcells.(Totalnumberofcellsis200,000.)Inbothcases(approximatedandrawdata),noindexeswereused.