無(wú)線環(huán)境中多數(shù)據(jù)項(xiàng)請(qǐng)求調(diào)度算法研究.pdf

1、復(fù)旦大學(xué)碩士學(xué)位論文無(wú)線環(huán)境中多數(shù)據(jù)項(xiàng)請(qǐng)求調(diào)度算法研究姓名：張卓瑤申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)：計(jì)算機(jī)軟件與理論指導(dǎo)教師：孫未未20090519AbstractDatabroadcasthasbeenacceptedasanefficientwayofdatadisseminationinthewire—lessmobileenvironmentWithbroadcastsystem，dataisbroadcastonthepublicdow

2、nlinkchannelClients’’listen’tothatchannelanddownloaddatathattheyareinterestedinInthiswaybroadcastingonedataitemCansatisfyallthependingquerieswhichrequirethatitemThesystemworkloadisindependentoftheclientsnumberintheservic

3、erangeAsaresult，oneservercansupportnumerousdataaccessqueriessimul—taneouslyTheaccesstime，whichmeansthetimeelapsedbetweenthemomentwhenaqueryisissuedandthemomentwhenthisqueryissatisfied，isacriticalmetrictOevaluatethebroadc

4、astingperformanceBroadcastscheduling，whichdetermineswhatt0bebroadcastandwhen，cangreatlyaffecttheaccesstime，thushasreceivedgreatattentionformtheresearchcommunityforalongtimeInthispaperwediscussabouttheschedulingmethodford

5、atabroadcastsystemwithspeciallyfocusonschedulingformulti—itemqueriesBroadcastformulti—itemqueryisabasicprobleminthisfieldsincemultiitemqueryiscommoninpracticalsituationsToOUrknowledge，lesspreviousworkhasproposedsincetheQ

6、EMalgorithmproposedin1999Inthisworkweproposeschedulingstrategyformulti—itemqueriesinbotllperiodicandondemandbroadcastmodeInperiodicbroadcastmode，weproposeahybridschedulingstrategywMchcombinestheadvantagesofthesquarerootm

7、lcandexistingschedulingalgorithmsformulti—itemqueriesSuchhybridschedul—ingstrategygivesbetterperformanceforschedulingmulti—itemqueriesespeciallythosewithskewedqueryaccessprobabilityInondemandbroadcastmode，wefirstadoptthe

8、paradigmbasedonbroadcastcyclesForthetwosubproblemswithsuchparadigm，thequeryselectionproblemandthebroadcastschedulingproblem，weproposeOUrnovelsolutionsforbothofthemrespectivelyOntheotherhand，wealsoproposeapreemptiveschedu

9、fingalgorithmformulti—itemqueriesItbreaksthroughthepreviousbroadcastcyclebasedparadigmandCanadaptgracefullyintheondemandenvironmentwithdynamicchangeofthequeryaccesspatternSimulationexperimentresultSshowsthatcomparedwitht