简介:WiththedevelopmentofCMOSandMEMStechnologies,theimplementationofalargenumberofwirelessdistributedmicro-sensorsthatcanbeeasilyandrapidlydeployedtoformhighlyredundant,self-configuring,andadhocsensornetworks.Tofacilitateeaseofdeployment,thesesensorsoperateonbatteryforextendedperiodsoftime.Aparticularchallengeinmaintainingextendedbatterylifetimeliesinachievingcommunicationswithlowpower.Forbetterunderstandingofthedesigntradeoffsofwirelesssensornetwork(WSN),amoreaccurateenergymodelforwirelesssensornodeisproposed,andanoptimaldesignmethodofenergyeffcientwirelesssensornodeisdescribedaswell.DifferentfrompowermodelsevershownwhichassumethepowercostofeachcomponentinWSNnodeisconstant,thenewonetakesintoaccounttheenergydissipationofcircuitsinpracticalphysicallayer.Itshowsthattherearesomeparameters,suchasdatarate,carrierfrequency,bandwidth,Tsw,etc,whichhaveasignificanteffectontheWSNnodeenergyconsumptionperusefulbit(EPUB).Foragivenqualityspecification,howenergyconsumptioncanbereducedbyadjustingoneormoreoftheseparametersisshown.
简介:HippocampalvolumelossisanimportantbiomarkerindistinguishingsubjectswithAlzheimer’sdisease(AD)anditsmeasurementinmagneticresonanceimages(MRI)isinfluencedbypartialvolumeeffects(PVE).Thispaperdescribesapost-processingapproachtoquantifyPVEforcorrectionofthehippocampalvolumebyusingaspatialfuzzyC-means(SFCM)method.Thealgorithmisevaluatedonadatasetof20T1-weightedMRIscanssampledattwodifferentresolutions.Thecorrectedvolumesforleftandrighthippocampus(HC)whichare23%and18%forthelowresolutionand6%and5%forthehighresolutiondatasets,respectivelyarelowerthanhippocampalvolumeresultsfrommanualsegmentation.ResultsshowtheimportanceofapplyingthistechniqueinADdetectionwithlowresolutiondatasets.
简介:ThispaperderivestheLindellformulabasedonthegeneralizedvariationalprinciple.ForthecomplexdielectricconstantmeasurementofasmalllossydielectricrodwithRayleigh-Ritzmethod,anaccuratevariationalanalysisisgiven.Theconceptofcomplexfrequencyisintroducedingeneral,andthestabilityofthesolutionisdiscussed.Comparingwiththeresultofperturbationmethod,itisconcludedthatthedeviationofperturbationalgorithmshouldbetakenintoconsideration.
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简介:MonteCarlosimulationofthediffusingtemporallightcorrelationinamulti-layeredturbidmediumisconsidered.Astraightforwardformulaisintroducedtocalculateaccuratelyandefficientlytheautocorrelationfunctionatanydetectorposition.Thesimulationresultsareinanexcellentagreementwithananalyticalsolutionofthecorrelationdiffusionequation.
简介:Thepaperfirstdiscussesshortcomingsofclassicaladjacent-framedifference.Secondly,basedontheimageenergyandhighorderstatistic(HOS)theory,backgroundreconstructionconstraintsaresetup.Underthehelpofblock-processingtechnology,backgroundisreconstructedquickly.Finally,backgrounddifferenceisusedtodetectmotionregionsinsteadofadjacentframedifference.TheDSPbasedplatformtestsindicatethebackgroundcanberecoveredlosslesslyinaboutonesecond,andmovingregionsarenotinfluencedbymovingtargetspeeds.Thealgorithmhasimportantusagebothintheoryandapplications.