在分布式層次結(jié)構中使用轉(zhuǎn)向指針及緩存技術解決移動計算中的尋址問題.pdf

1、西南師范大學碩士學位論文在分布式層次結(jié)構中使用轉(zhuǎn)向指針及緩存技術解決移動計算中的尋址問題姓名：李飛躍申請學位級別：碩士專業(yè)：計算機應用技術指導教師：程小平20030501useforwardingpointertolocatethemobileobjectinadistributedhierarchicaldatabaseInthisscheme，everydatabasesitecoversaspecialgeographicalre

2、gionandcontainslocationintbrmationaboutallobjectsresidinginitInhierarchicallocationsschemes，adatabaseathigherlayercontainsinformationaboutobjectsresidinginthesetoflogical—cello—celllinitssubtree，Alocationdatabaseataleafs

3、ervesasinglelcellandcontainsentriesforallobjectscurrentlyinthislcellForeachmobileobject，thisinformationisapointertoanentryatlowerleveldatabase。Forhighlymobileobjects，weuseforwardingpointerswithauxiliarycachingtechniquest

4、oreducethecostoftheoverallnetworkanddatabasetrafficgeneratedbyfrequentlocationupdatesTheschemeisextendtOsupportconcurrenceandfailurerecoveryItSadvancesat(1)DontneedtObindmobileobjectswithfixedHLR，anditcanavoidcircuity(2)

5、Whenobjectsmove，usingforwardingpointerdontneedtoupdatewhole、databasesinthepath，thiswillefficientlyreducethedatabaseSupdatingdegree(3)Usecachewillenhancethequeryefficiencyevenwhentheobjectmoves，withforwardingpointeritcanl

6、ocatetheoUjectexactlyFinally，wegivesomeresultsthroughasimulationexperimentforarangecalltomobility(CMR)anddifferentmovingandcallingbehaviorsTheexperimentresultsshowthatwhenmostcallarelocality，ourschemeworkedwell，iftheCMRi

7、ssmall，F(xiàn)01wcardingpointerwithcachecanreducethewholedatabaseloadandcommunicationtrafficby20％一6％Keywords：HomeLocationRegistEr，VisitorLocationRegisterMobileHandoverForwardingpointerCMR(calltoamobilityatmovingratio)，Circuity