港口规划与布置Chapter2Portcapacityandships

Chapter2Portcapacityandships2.1Cargoscategorizedbymannerofshipmentandhandling（根据运输和装卸方式分类的货物种类）2.2

Portcapacityandthroughput（港口通过能力及吞吐量）2.3

Determinationofberthrequirement（确定泊位数）2.4

Introductiontoqueuingtheory（排队论）2.5Moreapplicationcasesofqueuingtheory2.6

ShipsandtheirinfluenceonportdesignAccordingtothetransportationmode（运输方式）,wecanbasicallyclassify

cargo（货物）intofourcategories:Drybulkcargo（干散货）Liquidbulkcargo（液体散货）Containercargo（集装箱货）General(break)cargo（杂货）Drybulkcargo(干散货)suchkindsofmaterialsascoal,metalore,structuralmaterials,grain,saltcharacterisedbystableandlargequantity（稳定、大宗）;specializedloading/unloadingequipmentandhighhandlingefficiency（特殊、高效的装卸设备）.Chapter2Portcapacityandships2.1Cargoscategorizedbytrafficandhandlingmanner（根据运输和装卸方式分类的货物种类）Liquidbulkcargo(液体散货)coverssuchkindsofmaterialsasPetroleum（石油）LPG（液化石油气）,LNG（liquifiednaturalgas,液化天然气）Productsofpetroleum（石油产品）Vegetableoil（植物油）Characterisedbystableandlargequantity（稳定、大宗）;specializedloading/unloadingequipmentandhighhandlingefficiency（特殊、高效的装卸设备）;mostoftheliquidbulkcargosareflammable(可燃)andthusbelongtohazardous（危险）cargos.Somemayevenbetoxic（有毒）.Chapter2Portcapacityandships2.1CategoriesofcargoContainercargoandContainerisation（集装箱货和集装箱化）:(/)

Aspecialkindofcargo,usinglargenumberofboxeswithstandarizedsizetocontainbreakormiscellaneousgoods.（是一种采用标准化尺寸来装杂货的特殊货物）InventedintheUSduring1950s,originallyformilitaryuseandthenappliedtocommercialpurpose（上世界五十年代在美国发明，最初用于军事目的，后用于商业）.MaintypesintermsofsizeStandardtype:8×8×20ft.(width×height×length),calledtheTwenty-FootEquivalentUnit,TEU)Predominatedby20and40ftcontainers（以20和40吨箱为主）;Specialsize45ftinlength8.5ftor9.5fthighTotalweight:20.3~32.5t,netcargoweightisstatistically8tChapter2Portcapacityandships2.1CategoriesofcargoAdvantagesofusingcontainerastransportationtoolTobeadaptabletostandardizedhandlingequipments

可适应标准化装卸设备Highhandlingefficiency(装卸效率高)Toprovidesafeprotectionfordamageablegoods

为易损货物提供安全保护Door-to-door（门到门）andmultimodaltransportation（多式联运）servicesarepossible,cargoistransportedunderonethroughbill,issuedbytheshippingline;

可以实现门到门运输以及多式联运。Tobemoretimesavingincustomsprocessingandingoodshandover.

海关货物交接更省时.Chapter2Portcapacityandships2.1CategoriesofcargoGeneralcargo

Cargothatcannotbehandledwithspecializedequipments:不能用专业化装卸设备进行装卸的货物，如cartons(纸箱),crates(木箱),bales(捆),bags,drums(桶),etc.Characterisedby（特征是）Widely-varyingsizesandshapes（尺度、形状变化大）Largely-varyingcapabilityofloading/unloadingequipmentstoadaptthemiscellaneouscargo.要求装卸设备的能力变化大，以适应各类货物。Lowerhandlingefficiency.装卸效率低Ausefulandefficientwaytoimprovehandlingefficiency（装卸效率）istouselargeranduniformunits,whichiscalledunitizedhandlingorunitizedtransport

(成组装卸或成组运输).Oneunitweighsabout1.5-3tons.palletized(货盘)cartonspre-slung(吊索)bagsChapter2Portcapacityandships2.1Categoriesofcargo2.2Portcapacityandvolumeofthroughput

（港口通过能力及吞吐量）Portcapacity:Definedastheabilityofaporttohandlecargoinoneyear；Dependingonthetotalnumberofberthsandtheirefficiencies(thenumberandhandlingefficiencyofloading/unloadingequipments)总泊位数和各个泊位的装卸效率thestoragecapacity存储容量thetransportationlinkswiththehinterland与腹地的交通联系（集疏运系统）Thecapacityoftheaccesschannel(itsdepth,width,andone-wayortwo-way)航道通过能力，与深度、宽度及单向双向有关。thecustomsefficiency海关通关效率Chapter2Portcapacityandships2.2PortcapacityandthroughputNaturalconditions,suchasWinds(storms)Waves(swells)CurrentsFogNighttimerestrictionsforsomekindsofshipThus,agoodprotectionfromwavesandothernaturalenvironmentconditionswillgenerallyincreasetheworkabledayandhencethecapacityofaport.（因此，如果对于波浪或其它环境条件有良好保护，好的泊稳条件也会增加作业天数，故也会增加港口通过能力。）Chapter2Portcapacityandships2.2PortcapacityandthroughputOperationsystemofamodernportManeuveringandNavigationsystemLoadingandunloadingsystemStoragesystemLinkingtransportationsystemServicesystemCapacityofaportCargothroughput

isdefinedasthetotalannualvolumeofcargo（年货运量）loadedonandunloadedfromships.Insomeplaces,onetonofcargotransferredfromoneshiptotheotheriscountedtwice.Maininfluencingfactorsoncargothroughput

ofaport（影响港口货物吞吐量的主要因素）Trafficdemandofthehinterland

（腹地）andnumberofcallingships(靠泊船舶).Thevolumeofcargothroughput

willincreasemorerapidlywheneconomy,especiallymanufactureindustryinthehinterland,increasesfast.Efficiency

ofportfacilities(orcapacityofaport)may,ontheotherhand,alsohavesignificanteffectonthecargothroughput.Portcapacityandcargothroughputaretwoimportantindicestodescribethescaleofaportindifferentsense.（港口通过能力和吞吐量是两个描述港口规模大小的两个不同参量）Chapter2Portcapacityandships2.2PortcapacityandthroughputPortcapacityVolumeofcargothroughput=><TheoceanHinterlandisdefinedasanareawherecargocomesfromorgoesinto.Directhinterland(直接腹地)Transshipmenthinterland（转运腹地）ABPortPPortQFig.2.1DefinitionsketchofhinterlandCargoatMwhethertochoosePortAorBdependsonthetransportationcostsfromMtoAortoB.Chapter2Portcapacityandships2.2PortcapacityandthroughputForecastofportthroughput（吞吐量预测）Purposetoforecastportthroughput（港口吞吐量预测的目的）Todeterminethetypeandnumberofberthtobeconstructed.Toknowthecargotypeandthevolumepassingthroughaportandtheshiptype,tonnageandcallingfrequency.Methodofforecasting（预测方法）Quantitatively(定量方法):timeseriesforecasting,probabilityanalysismethod,casualrelationmethod,dynamicforecastingmethodandcombinedmethod.Qualitativemethod（定性方法）:Delphiforecasting,expertinvestigationmethodChapter2Portcapacityandships2.2PortcapacityandthroughputTime-seriesforecasting（时间序列法）Assumingthatthethroughputisrelatedwiththeorderofyears,aregressionrelation(回归关系)

betweenthethroughputandtheorderofyearscanbeobtainedbasedontheavailabledataofthroughput假定吞吐量与年序相关，以已有吞吐量资料为基础，建立吞吐量与年序回归关系。Probabilityanalysismethod（概率分析法）Theportthroughputdependsonmanyfactorsthatcontainrandomeffects.Basedontheavailabledataandestimationofthefuturedevelopmenttrend,itispossibletoevaluatethesubjectiveprobabilityofcertainthroughputvalue.吞吐量依赖于很多包含随机性的因子，根据已有资料和对未来发展趋势的预测，可以给出某吞吐量值的主观概率估计。Casualrelationmethod（因果关系法）Theportthroughputdependsonsocialandeconomicindices,suchasGDPandforeigntradevolume,etc.,fromthefuturetrendofthoseindices,portthroughputcanbeforecasted.港口吞吐量依赖于社会和经济指标，如GDP、外贸额等，从这些指标的未来发展趋向，可以预测港口吞吐量。Chapter2Portcapacityandships2.2PortcapacityandthroughputDelphiforecastingDevelopedbyRandCorporationin1950sMainprocedures:Aquestionnaireabouttheissuedesignedbyamonitorteamissenttoaselectedgroupofexperts.首先进行专家问卷调查。Aftertheresponsesaresummarized,theresultsaresentbackagaintotherespondentsforpossiblereevaluation.答卷汇总后，再送给答卷者，进行可能的重新评估。Therespondentsaregiventheopportunitytodefendtheiroriginalopinionortochangetheirpositiontoagreewiththemajorityinthesubsequentroundofquestionnaires.在接下来的问卷中，答卷者可以坚持其最初观点，也可以转为同意多数意见。Chapter2Portcapacityandships2.2PortcapacityandthroughputAssignmentICollectenoughdataofcontainerthroughputforaportthatyouchoose,basedonwhichperformpredictionofthethroughputofcontaineroftheyear2015and2020byatleastonemethodofthroughputforecast.Chapter2PortcapacityandshipsInconstructionofaport,themostimportantindextobedecidedinthefirststepmaybethenumberofberthstobeconstructedforgiventhroughput,cargotype,shipsize,andshiptonnage.建港时，最重要的指标就是给定吞吐量、货物种类以及船型建几个泊位。Ingeneral,thenumberofberthsshouldbedeterminedbasedontheconsiderationoffollowingfactors（确定泊位数时主要考虑以下因素）：predictedthroughputofvariouscargo(不同货物的吞吐量)averageshiptonnage(平均单船装载量)averagecargo-handlingrate(servicetime)anditsprobabilitydistributions(平均装卸效率及其概率分布)totalstayingtimeanditsprobabilitydistributions(总在港时间及其概率分布)probabilitydistributionsofships’arrivalrates（船舶到船率的概率分布）Chapter2Portcapacityandships2.3DeterminationofberthrequirementAsaruleofthumb,theberthnumbercanbecalculatedfromthepredicted

throughputofaportandthedesigned

handlingefficiency(装卸效率)ofasingleberth.(2.1)Chapter2Portcapacityandships2.3DeterminationofberthrequirementIntheplanningstage,thehandlingefficiencyofaberthPt

maybeestimatedfromempiricaldata,whichdependsonthecargotype,shiptonnage,andloading/unloadingoperation.TobemorepreciselyPtcanbecalculatedby(2.2)

Tyannualtotalservicetime(days);

tzservicetimeofoneship(hr.),;Chapter2Portcapacityandships2.3Determinationofberthrequirement

tf

auxiliaryoperation(辅助操作)time(hr.),includingmooringtime;

Rhandlingrateofaberth;

G

tonnageofshipment;thenon-servicetime(hr.),includingbreak,dining,etc.;

rtheutilizationfactorofaberth,theratiooftheutilizedtimetothetotaltime.Fordifferenttypeofberth,differenttypeofformulaareavailable.ConceptsofoptimumberthnumberandberthutilizationThepreviousruleofthumbindeterminationofberthnumbermaybemisleadingastheyignoretheinterestofshipownerswhilemakingthemawaitavailableberth.Sometimesthismaybeaveryseriousproblemwhentheutilizationisextraordinarily（异常地）highbecauseofthetworandomeventsinvolvinginportoperation:randomlengthofservicetime(loading/unloading),randomintervalofshiparrivals.Optimumberthnumbermustbeatradeoff（折中）oftheinterestsoftheportpartytheshipownerpartyInotherwords,theoptimumberthnumbermustbeafunctionthattakestheinterestofboththetwopartiesintoconsideration.Chapter2Portcapacityandships2.3DeterminationofberthrequirementTheoptimumberthnumber（最优泊位数）shouldbecorrespondingtothenumberwhenthetotalexpenseoftheberthsandthecallingvesselsgainstheminimum.Thereasonsare:最优泊位数应该对应于泊位费和船舶待泊费之和最小的情况下的泊位数，原因是Iftheberthnumberincreasedbyone,theportpartywilllosemoneyastheyinvesttoomuchinconstructionofberths.如果泊位数增加一个，港方会因为泊位太多而亏损。Whereasifitisdecreasedbyone,theshipownerpartymaybecomeunbearable（难以承受的）becauseoftoomuchwaitingtimeforavailableberth.而如果减少一个泊位，则船方会因为待泊时间过长而难以接受。Chapter2Portcapacityandships2.3DeterminationofberthrequirementOptimumberthutilization（最优泊位利用率）istheberthutilizationwhenberthnumberistheoptimum.0.47~0.75DependingonnumberandtypeofberthAsimplewaytodeterminetheoptimumberthnumber

isbycomparingthetotalexpenses

ofthetwopartiesunderthefollowingthreeconditions:KeeptheberthnumberunchangedLettheberthnumberincreaseoneLettheberthnumberdecreaseoneChapter2Portcapacityandships2.3DeterminationofberthrequirementMathematicalexpressionoftheoptimumberthnumberDenotethedailyexpenseofasingleberthbycb,whichincludestotalinitialinvestmentofthefixedfacilities（固定设备初投资）maintenanceexpenseoftheport（营运费）Denotethetotaldailyexpenseofashipbycs,whichincludesfixedcosts（固定费用）:

totalinitialinvestmentofthefixedfacilitiesoperationandmaintenanceexpenses（营运费）Thefixedcostsincludestheexpensesofshipfacilities,laborage,stuff(材料),broking(经纪),insurance,loaninterest,andetc.Theoperationandmaintenanceexpensesincludethecostsoffuel,electricity,andothersupplies.Chapter2Portcapacityandships2.3DeterminationofberthrequirementExpressionoftotalexpensesTotalberthnumberSnumberofshipsunderservice

+numberofships

waitingforberthvacancyTotaloperationdaysNinayearExpenseofaberthgroup

Cb=cbNS (2.3)Expenseofcallingships

Cs=csNns (2.4)Totalexpenseofboththeberthgroupandthecallingships (2.5)Chapter2Portcapacityandships2.3DeterminationofberthrequirementDefinitionoftheoptimumberthnumberSmustsatisfyand (2.6)Thusweobtain(2.7)and(2.8)Afteralittlemanipulation,wehave(2.9)Chapter2Portcapacityandships2.3DeterminationofberthrequirementThekeyproblemishowtoestimatethevaluesofns-1,ns,ns-1,andthelengthoftime

thatshipsstayatportforknownvaluesofcbandcsandotherbasicparameters,whichareallrandomvariables（随机变量）.CombiningEq.(2.8)and(2.9),wehave(2.10)QueuingtheorymodelOriginallydevelopedfordesigningtelephoneexchangesystembyA.N.Erlanginthelastcentury.Thecommoncharacteristicsofthetwoprocesses:randomarrivalsandrandomlengthofservicetime,correspondingtothetworandomevents:therandomarrivaltimeintervalofshipstherandomhandlingtimeofcargo2.4IntroductiontoqueuingtheoryChapter2Portcapacityandships••••••••••DepartureUnderserviceTotalnumberofshipsatportns=nw,s+nb,s

Givenquantities:ThroughputQAveragehandlingrateofship

mAveragevolumeofshipment

GAveragehandlingcapacityofcargo

RWedefinethe

averagearrivalrate（日到船率）andtrafficintensity（船流密度）

rs

istheberthutilization(berthoccupancy)(2.11)Chapter2Portcapacityandships2.4Introductiontoqueuingtheory(2.12)(2.13)Shiparrivalmaybeaheadofordelayedtothescheduleduetometeorologicalfactorsorotherunforeseenevents.Poissondistributionisusuallyagoodrepresentationfortheprobabilityofshiparrival.Thelengthofservicetimemayalsobedelayedwithrespecttoitsmeanbecauseofmeteorologicalinfluence,tidesandrandomnessincargohandlingoperations.Negative-exponentialdistribution

（负指数分布）isoftenusedforthedwelling（停留）timeofshipsatberth.Chapter2Portcapacityandships2.4Introductiontoqueuingtheory(2.14)ThusresultedmodeliscalledM/M/Smodel,inwhichtheprobabilityofnshipsdwellingatporthasananalyticalsolutionandcanbeexpressedasindicatesthesituationthatnoshipisatport.(2.15)Chapter2Portcapacityandships2.4IntroductiontoqueuingtheoryTheaveragenumberofwaitingshipscanthusbeexpressedas (2.16)Theaveragewaitingtimepershipcanbecalculatedby (2.17)Tb

istheservicetimepership,calculatedby (2.18)Chapter2Portcapacityandships2.4IntroductiontoqueuingtheoryThetotalnumberofshipsdwellingatportis(2-19)Fortheconvenienceofcalculation,atableiscreatedintermsofratioofwaitingtimetoservice-timeTw/TbnumberofberthsSberthoccupancyrs

BerthnumberUtilizationrs1234560.10.1110.0100.0010.0000.0000.0000.20.2500.0420.0100.0030.0010.0000.30.4290.0990.0330.0130.0060.0030.40.6670.1900.0780.0380.0200.0110.51.0000.3330.1580.0870.0520.0330.61.5000.5620.2960.1790.1180.0820.72.3330.9610.5470.3570.2520.1870.84.0001.7781.0790.7460.5540.4310.99.0001.2632.7241.9691.5251.234Table2.1Ratioofwaitingtimetoservice-time(M/M/Smodel)Chapter2Portcapacityandships2.4IntroductiontoqueuingtheoryProcedurestocalculatetheoptimumberthnumber:GivenvaluesofThroughputofaberthgroupQAveragehandlingcapacityofshipsmAveragetonnageofshipmentGAveragehandlingrateofcargoRBerthnumberSBerthutilizationrsChapter2Portcapacityandships2.4IntroductiontoqueuingtheoryExample1CalculatetheoptimumberthnumberforPortA,giventhethroughputQ=146×104ton/a,supposingshiparrivalsconformtoPoissondistributionandberthoccupationtimeconformstonegative-exponentialdistribution.Otherrelatedparametersareasfollows:Presentberthnumberis3.BerthhandlingrateR=2000ton/day·berthVolumeofshipmentG=5000ton/shipcs=2.92×104CNY/day·berthcb=8.00×104CNY/dayAnalysisThecapacityofasingleberth:48.7×104tons/yr.Inthiscase,theutilization(berthoccupancy)ishighupto67%thewaitingtimeofshipmaybetoolongthattheportwilllosecompetitiveability.Constructionofanewberthbecomesnecessary.Thiscanbeshownmoreclearlybythequeuingtheory.Chapter2Portcapacityandships2.4IntroductiontoqueuingtheoryForberthnumberof3,4,and5,therelatedparametersareshowninthefollowingtable.Table2.2Resultsofexample1Chapter2Portcapacityandships2.4IntroductiontoqueuingtheorySrsTwnw.snsns-ns+130.671.1380.9102.9140.500.2180.1742.1750.400.0500.0402.040.740.13TheoptimumberthnumberisthusS=4.Example2Estimatethewaitingcostofshipsinexample1forberthnumberS=3,4,and5,respectively.WhenS=4,theexpenselostofberthvacancy(泊位闲置损失)isTheexpenselostofshipwaitingforberthvacancyisChapter2Portcapacityandships2.4IntroductiontoqueuingtheoryDiscussionsTheberthexpenseisproportionaltotheberthnumber;Whiletheexpenseofthewaitingshipissharplydegressivewiththeincreaseofberthnumber;ThetotalexpenseofbothshipsandberthsgainsitsminimumwhenberthnumberS=4.Table2.3Resultsofexample2Chapter2Portcapacityandships2.4IntroductiontoqueuingtheoryS345Cb(×104CNY)1055.22131.63191.4Cs(×104CNY)2657.2508.1116.8Cb+Cs(×104CNY)3712.42639.73308.2ProbabilityofshiparrivalratePoissondistributionProbabilityofservicetimeSecond-orderErlangdistributionSelectionamongdifferentmodelsNegative-exponentialdistributionChapter2Portcapacityandships2.4IntroductiontoqueuingtheoryProbabilityofshiparrivalrateSecond-orderErlangdistributionProbabilityofservicetimeSecond-orderErlangdistributionStatisticdatashowsthatshiparrivaldistributionofgeneralcargoinmostportsconformsto(符合)Poisson

distribution.统计数据显示，多数港口杂货船到达符合泊松分布。Theoccupationtime(servicetime)ofshipsusuallyconformstoErlangdistribution.Insomeports,itconformstonegative-exponential

distribution.船舶在泊位时间（服务时间）一般爱尔兰分布。某些港符合负指数分布。Thearrivalrateoflinerships(班轮)oftenconformstothesecond-orderErlangdistributionbecauseshipandcargoownersareusuallyfixedandaremoreeasilytobescheduled.Randomnessusuallycomesfromnaturalfactors.So,theE2/E2/Smodeloftengivesmorerationalforecastresults.班轮到船率经常符合二阶爱尔兰分布，因为船和货主一般都是固定的，行程比较容易确定。随机性主要来自于自然因素。所以，

theE2/E2/S模型经常给出合理预报结果。Chapter2Portcapacityandships2.4IntroductiontoqueuingtheoryItisimportantfortheplannerstobeawareofthefactthattheforecastedresultsbymathematicalmodelreflectsonlythemosttypicalsituationandisasimplificationofthecomplexpicture.对于规划者来说，了解到数学模型预报结果只是反映了最典型情况和对复杂实际情况的简化是很重要的。Sometimesitmaybeoversimplifiedandthustheresultsmaybeunreasonable.有时甚至会因过于简化而使结果不合理。Inthissense,theforecastedresultsisonlyofvaluesofreferenceratherthanpreciseresults.在这个意义上，预报结果只能作为一种参考，而不能认定为精确结果。Chapter2Portcapacityandships2.4Introductiontoqueuingtheory2.5MoreapplicationcasesofqueuingtheoryConceptofberthgroupDuetotherandomfeaturesincargohandlingrateandshiparrivalrate,theservicequalitywilllikelybeimprovedifseveralberthsinaquayaremanagedasaunit(integratively,集中管理)

accordingtothequeuingtheory.Thiscanbeseenclearlyfromthefollowingdiscussions.由于在货物装卸及船舶到达中存在随机特征，根据排队论原理，如果几个泊位集中管理，服务质量很可能会提高。这可以从以下讨论中看出来。Chapter2PortcapacityandshipsExample3StrategyofmanagementCertainporthastwosectionsandeachhastwocontainerberths,respectively.Eachsectionhasthethroughputamountingto500,000TEU/a.TheshipmentisG=1000TEUpership.Theloading/unloadingtime1/m=0.8days/ship.某港有两个港区，每个港区有两个泊位，每个港区吞吐量为50万TEU，每艘船的平均装载量为1000TEU，装卸时间为1/m=0.8天/艘。UseM/E2/Smodel(PoissondistributionforshiparrivalandErlangdistributionforservicetime)tocomparetheadvantagesanddisadvantagesofintegrativeandindependentmanagement.用M/E2/S模型（船舶到达符合泊松分布，装船时间符合爱尔兰分布），对比集中和分散管理的优缺点。Chapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheoryManagedindependentlyFromTable4-8(textbook),itisinterpolatedshipsperdayChapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheoryManagedasaunitFromTable4-8(textbook),itisinterpolateddaysFromtheresults,wecanseethatalthoughtheequipmentsremainunchanged,thewaitingtimepershipisreducedby:从结果看出，尽管设备未变，待泊时间减少了0.244-0.0704=0.174day/shipTheannualamountofsavedtimeis（一年节约时间）Thecorrespondingexpense

savedperyearis(supposingtheexpenseofwaitingshipstobecb=172000CNY/ship·day):YuanRemarksAlthoughtheresultscannotbeabletoaccountforthecompletesituation,itdoinspireusthatsimilarberthsinaquaymanagedasaunitwillbesuperiortomanagedindependentlyintermsoftheirefficiency.虽然结果不能说明问题的全部，但给我们的启示是一个泊位组的相似的泊位综合管理优于分散管理。Chapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheoryAdvantageofincreasingloading/unloading(handling)efficiency提供装卸效率的好处Inordertocompletetheincreasingthroughputofaport,oneisoftenconfrontedwiththechoiceofwhethertoincreaseberthnumberortoimprovetheefficiencyofeachloading/unloadingequipmentsoastosatisfytheincreaseinportthroughput.为了完成不断增长的吞吐量要求，我们经常面临选择增加泊位数还是提高装卸效率Byusingthequeuingtheory,thequestioncanbeclarified(阐明)easily.运用排队论，问题可以得到澄清。Asshowninexample1,tocarryoutthethroughputof146×104tons,onesolutionistobuildanewberthwhilekeepingtheefficiencyofloading/unloadingfacilitiesunchanged.如例1所示，要完成146万吨的吞吐量，一种方案是新建一个泊位，而装卸效率不变。Chapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheoryWiththe4berths(3oldonesplus1newly-builtone),theberthutilizationfactorrs=50%andtheratioofwaitingtimetoservicetimeis0.087.Theportnowbecomesmorereadytoprovideserviceforcallingships.4个泊位情况下（3个已有，1个新建），泊位利用率为50%，待泊时间与范围时间之比为0.087，港口接近随到随靠。Isitthebestwaytoincreaseportcapacity?Ifnot,thenwhatwillhappenifweinvestmoreintheloading/unloadingfacilitiesinsteadofinconstructionofanewberth?增加泊位是最好办法吗？如果不是，那么如果投到装卸设备，而不是建新泊位会怎么样呢？Chapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheorySupposingthehandlingrateisincreasedfrom2000ton/dayto3000ton/daybyaddingonemorehandlingline,inwhichcase,FromTable4-8(textbook),itisinterpolatedday/shipdaydayTheaveragetimeofashipatportisChapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheoryImprovedOriginalfacilities0.218+2.5=2.720.2180.5S=4;Increasingoneberth0.142+1.67=1.810.1420.44S=3;Increasinghandlingrateby50%Table2.4ComparisonamongdifferentstrategyChapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheoryConcludingremarks:Thetotaltimeofshipsstayingatportbeforeanyinvestmentisthelargestsinceboththewaitingtimeandtheservicetimearemorethanthoseafterinvestmentofnewfacilities;在任何投资实施之前，船舶全部在港时间为最大，因为待泊时间和服务时间都比改善之前都大。Thewaitingtimeisdecreasedsignificantlyaftertheconstructionofonemoreberth,howevertheservicetimestillremainsunchanged,consequentlythetotaltimeisstillatahighlevel;建成一个泊位后待泊时间显著减小，但服务时间不变，因此，总在港时间仍然较大。Chapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheoryByincreasingonesetofloading/unloadingline,i.e.,thehandlingrateisincreasedby50%,boththewaitingtimeandtheservicetimearereducedeffectivelyandthetotaltimegainsminimum;增加一套装卸设备后，装卸效率提高50%，待泊时间和服务时间都显著减少，总在港时间也达到最小。Theexampleindicatesthatimprovementofhandlingrateismoreeffectiveinsavingstaytimethanincreasingberthnumber.

这个例子表明，提高装卸效率比起增加泊位对于节省在港时间更有效。Thisiswhymodernportprefersusinghighly-efficientloading/unloadingequipmentstosolelyincreasingberthnumberwhilekeepingusingloading/unloadingequipmentsoflow-efficiency.这就是为什么现代港口大都采用高效率的装卸机械，而不是靠单纯增加泊位数量，而装卸机械维持原状。Chapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheoryHowtoarrangethechanceofimprovingportcapacity

怎样安排提高港口通过能力的时机Berthutilizationfactorhassignificantinfluenceontheservicequalityofaport.泊位利用率对于港口的服务质量有很大影响Fromtheformula,itcanbeseenthatifthehandlingrate

Randtheberthnumber

Sremainunchanged,theutilizationfactorhastobeincreasedinordertosatisfythedesignatedthroughput.从公式可以看出，如果泊位数保持不变，为了完成吞吐量，必须提高泊位利用率。RatioofwaitingtimetoservicetimeUtilizationfactorChapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheoryItcanbeconcludedthatthelowertheutilizationfactoris,thebetterservicequalityaportwillpossess.泊位利用率越低，服务质量越好。Whentheutilizationfactorreachessuchahighdegreeastheservicequalityofaportisseriouslyaffected,const