英文学术报告PPT课件

.,1,ModelingtheQoEofRateChangesinSkype/SILKVoIPCalls,.,2,Layout,BACKGROUNDPRELIMINARYEXPERIMENTPROPOSEDMODELFixed-RateModelVariable-RateModelLARGE-SCALEEXPERIMENTEVALUATIONCONCLUSIONANDFUTUREWORK,.,3,Background,THEEFFECTIVEend-to-endtransportofdelay-sensitivevoicedatahaslongbeenasubjectofstudyinmultimedianetworking.user-centricapproachrateadaptationmechanismsWeberFechnersLawEarlyrate-controlmechanismsattemptedtoimproveQoSforthedatadelivered.Anincreasingtrendinthisareaistomeasurenetworkservicesusingthequalityofexperience(QoE).QoSQoESynergyrateadaptationmechanismsQoE-BasedAdaptationPsychophysics,PRELIMINARYEXPERIMENT,MOSbit-rateplotoffixedratetests,Thepurposeofthepreliminaryexperimentinthisstudywastoexamine,throughusertests,whetherchangesinsendingratesdecreasestheuserexperience,andatwhatscaletheMOSisinfluencedbythemagnitudeandfrequencyofchanges.,.,5,PROPOSEDMODEL,A.Fixed-RateModel,wherebristhebitrate,and,andarecoefficientstobedeterminedbySILKcharacteristics.Thebit-rateshift()iscausedbythelimitofhumanperception.Accordingtotheformula,thetermbr-,beinginsidetheoperator,canonlybepositive.,.,6,PROPOSEDMODEL,B.Variable-RateModel,wheretheeffectofchangefrequencyisdistributedtothelogarithmterm,andtheeffectofhrandlrisdistributedtothetwosubroutines,SCALE()andSHIFT().,.,7,LARGE-SCALEEXPERIMENT,A.ANOVATests,NonparallelMOSTrelationshipsindicateinteraction,Inthat,andarethemeanandstandarddeviationofallscoresobtainedfromtracksofthesame(hr,lr)pair.Thez-scorewasthenusedforANOVAtests.,.,8,LARGE-SCALEEXPERIMENT,B.ModelSpecifics,1)CoefficientsofFixed-RateFormula,2)SubroutineofVariable-RateFormula,3)SubroutineofVariable-RateFormula,.,9,EVALUATION,A.PredictionAccuracy,Goodnessoffitoftrainingdata,ThescatterplotinFigshowsthefittedscore(asthe-axis)andtheuserscore(asthe-axis)foreachratepairandtimeintervaltestset,.,10,EVALUATION,A.PredictionAccuracy,Accuracyofprediction,Figshowstheaccuracyoftheproposedmodel.Inthisfigure,thepredictionsofbothdatasetscloselytrackthemeasureddata,regardlessofthedifferenceinaudiocontentandspeaker,.,11,EVALUATION,B.ComparisontoPESQ,1)FixedRate,Predictionerror:SILKversusPESQforfixed-ratetracks,Forthefixed-ratecomparison,weincludedtracksinboththepreliminaryandlarge-scaleexperiment,.,12,EVALUATION,B.ComparisontoPESQ,2)VariableRate,Predictionerror:SILKversusPESQforfixed-ratetracks,Asimilarcomparisonwasalsoconductedforvariabletracks,andtheaccuracyofpredictionofboththeproposedmodelandPESQareindicatedinFig,.,13,CONCLUSIONANDFUTUREWORK,A.QoEMeasurement,Inthisstudy,wequantifytherelationshipbetweenuserexperienceandbitratechangesforSkype/SILKcalls.,B.NetworkDesign,Asolidunderstandingofmultimediacontentisfundamentaltobetterengineeringofthenetworkapplications.,C.MultimediaContent,TakingSkypea