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X(210016),,,,,,,,TheApplicationsofWaveletTransforminOilLeakageOnlineDetectionChenRenwen(NanjingUniversityofAeronautics&Astronautics,Nanjing210016,China)AbstractHowtoanalysethemeasuredstresswavesignalforanoilleakagemonitoringsystemtogetthefeaturesandthemodesofmanmadeleakagesisthekeyproblemforaccuratedetection.Itintroducestheprincipalschemeoftheleakagedetectionsystemaswellasawavelettransformmethodforsignalprocessing.Signalde2noisingapproachesarediscussedbytakinguseoftherelationsbetweenthesignal’swaveletcoefficientsanditssingularity,andanexampleisgivenforthemethod.Fieldexperimentsarecarriedoutforvalidation,whichshowthatamajorityofnoisesareeliminatedandthesystemdetectionaccuracyisimproved.KeywordsWavelettransformOilpipelineLeakagedetectionOn2linedetection1,,[16],,,,,,,,,,,,,,,,,,,,,,,,,,,,26320053X200352,,,,,,,,1,AöDCMOSDC2DC,15,,,,()13,,,,1946Gabor,1984GrossmannMorlet[7]f(t)L2(R),[89]:WTf(a,S)=f(t),7a,S(t)=a-12Rf(t)73(t-Sa)dt(1):73(.)7(.),WTf(a,S)f(t)aS7(t),7a,S(t)7(t)aS(STFT),S(),a$tX0öa$X0öa,,,:WTf(j,k)=12jf(t)73(2-jt-k)dt(j,kZ)(2),,,,,,[8](L.E.,Lipschitzexponent)L.E.Q:f(t)t0:ûf(t0+N)-Pn(t0+N)ûKûNûQnQn+1(3):N,K,Pn(t0+N)f(t)t0nQf(t)t0Q,,(),,L.E.1,L.E.0,-1,-1ö2,Q1,Q:ûWTf(a)ûKaQ(4)3423:logûWTf(a)ûlogK+Qloga(5),2,:log2ûWTf(2j)ûlog2K+jQ(6):j,Q0,,Q0,,Q=0(),,,,L.E.,,L.E.0,()L.E.0,,;,,,,,,4,2(a)(b)(c)300m800m1200m,2(a),,,coif5[9],5,coif5,5d1d5,d1d3,,(),d4d5,d1d2d3,d4d5,0102001021010210102101021d1d5,,,33(a),3(b)23,16km44226,1200m51m,10m90,,,,11,5m,1m1231474275382494245363494225362525,,,,,,,,1MandalK,AthertonDL.Astudyofmagneticflux2leakagesignals.JournalofPhysicsD(AppliedPhysics),31(22):32113217.2RajtarJM,MuthiahR.Pipelineleakdetectionsystemforoilandgasflowlines.JournalofManufacturingScienceandEngineering,TransactionsoftheASME,1997,119(1):105109.3,..,2000,(1):3841.4,..,2000,(2):1213.5,..,2000,(4):9396.6,..,2000,(5):5658.7GrossmannA,MorletJ.Cycle2octaveandrelatedtransformsinseismicsignalanalysis.Geoexploration,1985,(23):85102.8MallatSG.Characterizationofsignalsfrommultiscalesedges.NYU,ComputerScienceTech.Report,1991.9CoifmanR,WickerhauserMV.Entropybasedalgorithmsforbestbasicselection.IEEETransonInform.Theory,1992,38:713718.(237)(2)7,FNRC,75,,[2],,,1,..,1999,(6):2528.2,,...1996,18(4):4346.3,,.PWM.EACS,1996,(8).4,,.PID.EACS,1996,(8).5M.H.Perng,H.H.Chang.Intelligentsupervisionofservocontrol.IEEProceeding2D,November1993.5423