简介:Objective:Thereisnosaferwaytotransportachildthanaschoolbus.FatalcrashesinvolvingoccupantsareextremelyrareeventsintheUS.Inrecentyears,schoolbustransportationbegantodevelopinChina.WewanttobringadvancedexperienceonschoolbussafetyinWesterncountriessuchastheUStodevelopingcountries.Methods:WesearchedthepapersrelatedtoschoolbussafetyfromMedline,ChineseScientificJournalsDatabaseandtheWeboftheNationalHighwayTrafficSafetyAdministration(NHTSA).Results:Therewereonly9papersrelatedtoschoolbussafety,whichshowedthathigherlevelsofsafetystandardsonschoolbuses,schoolbus-relatedtransportationandenvironmentallawsandinjurypreventionweretheprimaryreasonsforthedesiredoutcome.Fewschoolbusisrelatedtodeathsandinjuriesinthedevelopedcountries.Conclusions:Thedevelopingcountriesshouldmakestrictenvironmentallawsandstandardsonschoolbussafetytopreventchildren'sinjuryanddeath.
简介:ThelimitsofparameterγinFASTTCParestudiedinthispaper.AcontinuoustimefluidflowmodelofthelinkbufferisconsideredtocreatealinearcontrolsystemrelatedtoFASTTCP.Linearingthefluidflowmodelandwindowcontrolmodel,theLaplacetransformversionofcongestioncontrolsystemarepresented.Itresultsinanegativefeedbacksystemwithopenlooptransferfunction.WiththeanalysisofNyquistcurveofthesystem,asufficientconditiononasymptoticalstabilityofFASTTCPcongestionwindowrelatedtotheparameterγisobtained.Packetlevelns-2simulationsareusedtoverifythetheoreticalclaims.
简介:TheARGO-YBJexperimentispresentlyunderconstructionattheYangbaijinghighAltitudeComsmicRayLaboratory(4300ma.s.l).90KmNorthtoLhasa(Tibet,peolpl'sRepublicofChina)ARGO-YBJwillstudyfundamentalissuesincosmicrayandastroparticlephysicsbydetectingsmallsizeairshowers.Thedetectorcovers-71×74squaremeterswithasinglelayerofresistivePlateCounters(RPCs),surroundedbyaguardringpartiallyinstrumented.Anevent-drivendatacollectionschemeisimplementedbyusingacustombusprotocol./Keyfeaturesofthisarchitectureareblock-orienteddatatransferandread-outcycleslabeledbytriggernumber,HardwareenginesinbothmasterandDAQboardshandlebustransactionsandprovideeventbuilingcapability,achievingreal-timedataprocessingwithnosoftwareoverhead.InthispaperwepresentthehardwaredesignoftheARGOexperiment'sDAQwhichbenefitsfromtheflexiblearchitectureofin-systemreconfigurableFPGAs.Thedataacquistitionboardsspecificallydevelopedforthisapplicationwillbedescribed.
简介:DuetotheproblemsarisingwhentheTransmissionControlProtocol(TCP)isappliedoverwirelessnetworks,manyTCPperformanceenhancementmechanismshavebeenproposed.However,suchmechanismsaren'tcompatiblewithIPSecprotocol.ThepaperreviewstheTCPperformanceenhancementmechanismsinwirelessnetworks.Thentheconflictsbetweenthemareanalyzed.Severalproposalsforsolvingtheconflictsarediscussed,andtheirbenefitandlimitationsareexamined.