外文翻译 zigbee检测探头在冷藏蔬菜运输现实条件下的测试大学论文Word文件下载.docx

外文翻译 zigbee检测探头在冷藏蔬菜运输现实条件下的测试大学论文Word文件下载.docx

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10128

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本科毕业设计

外文文献及翻译

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英文题目：

TestingZigBeeMotesforMonitoringRefrigeratedVegetableTransportationunderRealConditions

中文题目：

ZigBee检测探头在冷藏蔬菜运输现实条件下的测试

学生姓名：

学院：

信息工程学院

系别：

电子信息工程

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班级：

指导教师：

教授

二〇一年月

Abstract

Qualitycontrolandmonitoringofperishablegoodsduringtransportationanddeliveryservicesisanincreasingconcernforproducers,suppliers,transportdecisionmakersandconsumers.Themajorchallengeistoensureacontinuous„coldchain‟fromproducertoconsumerinordertoguarantyprimeconditionofgoods.Inthisframework,thesuitabilityofZigBeeprotocolformonitoringrefrigeratedtransportationhasbeenproposedbyseveralauthors.However,uptodatetherewasnotanyexperimentalworkperformedunderrealconditions.Thus,themainobjectiveofourexperimentwastotestwirelesssensormotesbasedintheZigBee/IEEE802.15.4protocolduringarealshipment.Theexperimentwasconductedinarefrigeratedtrucktravelingthroughtwocountries（SpainandFrance）whichmeansajourneyof1,051kilometers.Thepaperillustratesthegreatpotentialofthistypeofmotes,providinginformationaboutseveralparameterssuchastemperature,relativehumidity,dooropeningsandtruckstops.Psychrometricchartshavealsobeendevelopedforimprovingtheknowledgeaboutwaterlossandcondensationontheproductduringshipments.

1.Introduction

Perishablefoodproductssuchasvegetables,fruit,meatorfishrequirerefrigeratedtransportation.Foralltheseproducts,Temperature（T）isthemostimportantfactorforextendingshelflife,beingessentialtoensurethattemperaturesalongthecoldchainareadequate.However,localtemperaturedeviationscanbepresentinalmostanytransportsituation.Reportsfromtheliteratureindicategradientsof5°

Cormore,whendeviationsofonlyafewdegreescanleadtospoiledgoodsandthousandsofEurosindamages.Arecentstudyshowsthatrefrigeratedshipmentsriseabovetheoptimumtemperaturein30%oftripsfromthesuppliertothedistributioncentre,andin15%oftripsfromthedistributioncentretothestores.Royetal.analyzedthesupplyoffreshtomatoinJapanandquantifiedproductlossesof5%duringtransportationanddistribution.Thermalvariationsduringtransoceanicshipmentshavealsobeenstudied.Theresultsshowedthattherewasasignificanttemperaturevariabilitybothspatiallyacrossthewidthofthecontaineraswellastemporallyalongthetrip,andthatitwasoutofthespecificationmorethan30%ofthetime.Inthoseexperimentsmonitoringwasachievedbymeansoftheinstallationofhundredsofwiredsensorsinasinglecontainer,whichmakesthissystemarchitecturecommerciallyunfeasible.

Transportisoftendonebyrefrigeratedroadvehiclesandcontainersequippedwithembeddedcoolingsystems.Insuchenvironments,temperaturesriseveryquicklyifareeferunitfails.Commercialsystemsarepresentlyavailableformonitoringcontainersandtrucks,buttheydonotgivecompleteinformationaboutthecargo,becausetheytypicallymeasureonlytemperatureandatjustonepoint.

Apartfromtemperature,waterlossisoneofthemaincausesofdeteriorationthatreducesthemarketabilityofperishablefoodproducts.Transpirationisthelossofmoisturefromlivingtissues.Mostweightlossofstoredfruitiscausedbythisprocess.Relativehumidity（RH）,Toftheproduct,Tofthesurroundingatmosphere,andairvelocityallaffecttheamountofwaterlostinfoodcommodities.Freewaterorcondensationisalsoaproblemasitencouragesmicrobialinfectionandgrowth,anditcanalsoreducethestrengthofpackagingmaterials.

Partiesinvolvedneedbetterqualityassurancemethodstosatisfycustomerdemandsandtocreateacompetitivepointofdifference.Successfultransportinfoodlogisticscallsforautomatedandefficientmonitoringandcontrolofshipments.Thechallengeistoensureacontinuous„coldchain‟fromproducertoconsumerinordertoguarantyprimeconditionofgoods.

TheuseofwirelesssensorsinrefrigeratedvehicleswasproposedbyQingshanetal.asanewwayofmonitoring.SpecializedWSN（WirelessSensorNetwork）monitoringdevicespromisetorevolutionizetheshippingandhandlingofawiderangeofperishableproductsgivingsuppliersanddistributorscontinuousandaccuratereadingsthroughoutthedistributionprocess.Inthisframework,ZigBeewasdevelopedasaverypromisingWSNprotocolduetoitslowenergyconsumptionandadvancednetworkcapabilities.Itspotentialformonitoringthecoldchainhasbeenaddressedbyseveralauthorsbutwithoutrealexperimentation,onlytheoreticalapproaches.Forthisreason,inourworkrealexperimentationwiththeaimofexploringthelimitsofthistechnologywasapriority.

Themainobjectiveofthisproj