港口規(guī)劃與布置Chapter2Portcapacityandships

Chapter2Portcapacityandships2.1Cargoscategorizedbymannerofshipmentandhandling（根據(jù)運輸和裝卸方式分類的貨物種類）2.2

Portcapacityandthroughput（港口通過能力及吞吐量）2.3

Determinationofberthrequirement（確定泊位數(shù)）2.4

Introductiontoqueuingtheory（排隊論）2.5Moreapplicationcasesofqueuingtheory2.6

ShipsandtheirinfluenceonportdesignAccordingtothetransportationmode（運輸方式）,wecanbasicallyclassify

cargo（貨物）intofourcategories:Drybulkcargo（干散貨）Liquidbulkcargo（液體散貨）Containercargo（集裝箱貨）General(break)cargo（雜貨）Drybulkcargo(干散貨)suchkindsofmaterialsascoal,metalore,structuralmaterials,grain,saltcharacterisedbystableandlargequantity（穩(wěn)定、大宗）;specializedloading/unloadingequipmentandhighhandlingefficiency（特殊、高效的裝卸設(shè)備）.Chapter2Portcapacityandships2.1Cargoscategorizedbytrafficandhandlingmanner（根據(jù)運輸和裝卸方式分類的貨物種類）Liquidbulkcargo(液體散貨)coverssuchkindsofmaterialsasPetroleum（石油）LPG（液化石油氣）,LNG（liquifiednaturalgas,液化天然氣）Productsofpetroleum（石油產(chǎn)品）Vegetableoil（植物油）Characterisedbystableandlargequantity（穩(wěn)定、大宗）;specializedloading/unloadingequipmentandhighhandlingefficiency（特殊、高效的裝卸設(shè)備）;mostoftheliquidbulkcargosareflammable(可燃)andthusbelongtohazardous（危險）cargos.Somemayevenbetoxic（有毒）.Chapter2Portcapacityandships2.1CategoriesofcargoContainercargoandContainerisation（集裝箱貨和集裝箱化）:(/)

Aspecialkindofcargo,usinglargenumberofboxeswithstandarizedsizetocontainbreakormiscellaneousgoods.（是一種采用標(biāo)準(zhǔn)化尺寸來裝雜貨的特殊貨物）InventedintheUSduring1950s,originallyformilitaryuseandthenappliedtocommercialpurpose（上世界五十年代在美國發(fā)明，最初用于軍事目的，后用于商業(yè)）.MaintypesintermsofsizeStandardtype:8×8×20ft.(width×height×length),calledtheTwenty-FootEquivalentUnit,TEU)Predominatedby20and40ftcontainers（以20和40噸箱為主）;Specialsize45ftinlength8.5ftor9.5fthighTotalweight:20.3~32.5t,netcargoweightisstatistically8tChapter2Portcapacityandships2.1CategoriesofcargoAdvantagesofusingcontainerastransportationtoolTobeadaptabletostandardizedhandlingequipments

可適應(yīng)標(biāo)準(zhǔn)化裝卸設(shè)備Highhandlingefficiency(裝卸效率高)Toprovidesafeprotectionfordamageablegoods

為易損貨物提供安全保護(hù)Door-to-door（門到門）andmultimodaltransportation（多式聯(lián)運）servicesarepossible,cargoistransportedunderonethroughbill,issuedbytheshippingline;

可以實現(xiàn)門到門運輸以及多式聯(lián)運。Tobemoretimesavingincustomsprocessingandingoodshandover.

海關(guān)貨物交接更省時.Chapter2Portcapacityandships2.1CategoriesofcargoGeneralcargo

Cargothatcannotbehandledwithspecializedequipments:不能用專業(yè)化裝卸設(shè)備進(jìn)行裝卸的貨物，如cartons(紙箱),crates(木箱),bales(捆),bags,drums(桶),etc.Characterisedby（特征是）Widely-varyingsizesandshapes（尺度、形狀變化大）Largely-varyingcapabilityofloading/unloadingequipmentstoadaptthemiscellaneouscargo.要求裝卸設(shè)備的能力變化大，以適應(yīng)各類貨物。Lowerhandlingefficiency.裝卸效率低Ausefulandefficientwaytoimprovehandlingefficiency（裝卸效率）istouselargeranduniformunits,whichiscalledunitizedhandlingorunitizedtransport

(成組裝卸或成組運輸).Oneunitweighsabout1.5-3tons.palletized(貨盤)cartonspre-slung(吊索)bagsChapter2Portcapacityandships2.1Categoriesofcargo2.2Portcapacityandvolumeofthroughput

（港口通過能力及吞吐量）Portcapacity:Definedastheabilityofaporttohandlecargoinoneyear；Dependingonthetotalnumberofberthsandtheirefficiencies(thenumberandhandlingefficiencyofloading/unloadingequipments)總泊位數(shù)和各個泊位的裝卸效率thestoragecapacity存儲容量thetransportationlinkswiththehinterland與腹地的交通聯(lián)系（集疏運系統(tǒng)）Thecapacityoftheaccesschannel(itsdepth,width,andone-wayortwo-way)航道通過能力，與深度、寬度及單向雙向有關(guān)。thecustomsefficiency海關(guān)通關(guān)效率Chapter2Portcapacityandships2.2PortcapacityandthroughputNaturalconditions,suchasWinds(storms)Waves(swells)CurrentsFogNighttimerestrictionsforsomekindsofshipThus,agoodprotectionfromwavesandothernaturalenvironmentconditionswillgenerallyincreasetheworkabledayandhencethecapacityofaport.（因此，如果對于波浪或其它環(huán)境條件有良好保護(hù)，好的泊穩(wěn)條件也會增加作業(yè)天數(shù)，故也會增加港口通過能力。）Chapter2Portcapacityandships2.2PortcapacityandthroughputOperationsystemofamodernportManeuveringandNavigationsystemLoadingandunloadingsystemStoragesystemLinkingtransportationsystemServicesystemCapacityofaportCargothroughput

isdefinedasthetotalannualvolumeofcargo（年貨運量）loadedonandunloadedfromships.Insomeplaces,onetonofcargotransferredfromoneshiptotheotheriscountedtwice.Maininfluencingfactorsoncargothroughput

ofaport（影響港口貨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.（港口通過能力和吞吐量是兩個描述港口規(guī)模大小的兩個不同參量）Chapter2Portcapacityandships2.2PortcapacityandthroughputPortcapacityVolumeofcargothroughput=><TheoceanHinterlandisdefinedasanareawherecargocomesfromorgoesinto.Directhinterland(直接腹地)Transshipmenthinterland（轉(zhuǎn)運腹地）ABPortPPortQFig.2.1DefinitionsketchofhinterlandCargoatMwhethertochoosePortAorBdependsonthetransportationcostsfromMtoAortoB.Chapter2Portcapacityandships2.2PortcapacityandthroughputForecastofportthroughput（吞吐量預(yù)測）Purposetoforecastportthroughput（港口吞吐量預(yù)測的目的）Todeterminethetypeandnumberofberthtobeconstructed.Toknowthecargotypeandthevolumepassingthroughaportandtheshiptype,tonnageandcallingfrequency.Methodofforecasting（預(yù)測方法）Quantitatively(定量方法):timeseriesforecasting,probabilityanalysismethod,casualrelationmethod,dynamicforecastingmethodandcombinedmethod.Qualitativemethod（定性方法）:Delphiforecasting,expertinvestigationmethodChapter2Portcapacityandships2.2PortcapacityandthroughputTime-seriesforecasting（時間序列法）Assumingthatthethroughputisrelatedwiththeorderofyears,aregressionrelation(回歸關(guān)系)

betweenthethroughputandtheorderofyearscanbeobtainedbasedontheavailabledataofthroughput假定吞吐量與年序相關(guān)，以已有吞吐量資料為基礎(chǔ)，建立吞吐量與年序回歸關(guān)系。Probabilityanalysismethod（概率分析法）Theportthroughputdependsonmanyfactorsthatcontainrandomeffects.Basedontheavailabledataandestimationofthefuturedevelopmenttrend,itispossibletoevaluatethesubjectiveprobabilityofcertainthroughputvalue.吞吐量依賴于很多包含隨機性的因子，根據(jù)已有資料和對未來發(fā)展趨勢的預(yù)測，可以給出某吞吐量值的主觀概率估計。Casualrelationmethod（因果關(guān)系法）Theportthroughputdependsonsocialandeconomicindices,suchasGDPandforeigntradevolume,etc.,fromthefuturetrendofthoseindices,portthroughputcanbeforecasted.港口吞吐量依賴于社會和經(jīng)濟指標(biāo)，如GDP、外貿(mào)額等，從這些指標(biāo)的未來發(fā)展趨向，可以預(yù)測港口吞吐量。Chapter2Portcapacityandships2.2PortcapacityandthroughputDelphiforecastingDevelopedbyRandCorporationin1950sMainprocedures:Aquestionnaireabouttheissuedesignedbyamonitorteamissenttoaselectedgroupofexperts.首先進(jìn)行專家問卷調(diào)查。Aftertheresponsesaresummarized,theresultsaresentbackagaintotherespondentsforpossiblereevaluation.答卷匯總后，再送給答卷者，進(jìn)行可能的重新評估。Therespondentsaregiventheopportunitytodefendtheiroriginalopinionortochangetheirpositiontoagreewiththemajorityinthesubsequentroundofquestionnaires.在接下來的問卷中，答卷者可以堅持其最初觀點，也可以轉(zhuǎn)為同意多數(shù)意見。Chapter2Portcapacityandships2.2PortcapacityandthroughputAssignmentICollectenoughdataofcontainerthroughputforaportthatyouchoose,basedonwhichperformpredictionofthethroughputofcontaineroftheyear2015and2020byatleastonemethodofthroughputforecast.Chapter2PortcapacityandshipsInconstructionofaport,themostimportantindextobedecidedinthefirststepmaybethenumberofberthstobeconstructedforgiventhroughput,cargotype,shipsize,andshiptonnage.建港時，最重要的指標(biāo)就是給定吞吐量、貨物種類以及船型建幾個泊位。Ingeneral,thenumberofberthsshouldbedeterminedbasedontheconsiderationoffollowingfactors（確定泊位數(shù)時主要考慮以下因素）：predictedthroughputofvariouscargo(不同貨物的吞吐量)averageshiptonnage(平均單船裝載量)averagecargo-handlingrate(servicetime)anditsprobabilitydistributions(平均裝卸效率及其概率分布)totalstayingtimeanditsprobabilitydistributions(總在港時間及其概率分布)probabilitydistributionsofships’arrivalrates（船舶到船率的概率分布）Chapter2Portcapacityandships2.3DeterminationofberthrequirementAsaruleofthumb,theberthnumbercanbecalculatedfromthepredicted

throughputofaportandthedesigned

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

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

Tyannualtotalservicetime(days);

tzservicetimeofoneship(hr.),;Chapter2Portcapacityandships2.3Determinationofberthrequirement

tf

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

Rhandlingrateofaberth;

G

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

rtheutilizationfactorofaberth,theratiooftheutilizedtimetothetotaltime.Fordifferenttypeofberth,differenttypeofformulaareavailable.ConceptsofoptimumberthnumberandberthutilizationThepreviousruleofthumbindeterminationofberthnumbermaybemisleadingastheyignoretheinterestofshipownerswhilemakingthemawaitavailableberth.Sometimesthismaybeaveryseriousproblemwhentheutilizationisextraordinarily（異常地）highbecauseofthetworandomeventsinvolvinginportoperation:randomlengthofservicetime(loading/unloading),randomintervalofshiparrivals.Optimumberthnumbermustbeatradeoff（折中）oftheinterestsoftheportpartytheshipownerpartyInotherwords,theoptimumberthnumbermustbeafunctionthattakestheinterestofboththetwopartiesintoconsideration.Chapter2Portcapacityandships2.3DeterminationofberthrequirementTheoptimumberthnumber（最優(yōu)泊位數(shù)）shouldbecorrespondingtothenumberwhenthetotalexpenseoftheberthsandthecallingvesselsgainstheminimum.Thereasonsare:最優(yōu)泊位數(shù)應(yīng)該對應(yīng)于泊位費和船舶待泊費之和最小的情況下的泊位數(shù)，原因是Iftheberthnumberincreasedbyone,theportpartywilllosemoneyastheyinvesttoomuchinconstructionofberths.如果泊位數(shù)增加一個，港方會因為泊位太多而虧損。Whereasifitisdecreasedbyone,theshipownerpartymaybecomeunbearable（難以承受的）becauseoftoomuchwaitingtimeforavailableberth.而如果減少一個泊位，則船方會因為待泊時間過長而難以接受。Chapter2Portcapacityandships2.3DeterminationofberthrequirementOptimumberthutilization（最優(yōu)泊位利用率）istheberthutilizationwhenberthnumberistheoptimum.0.47~0.75DependingonnumberandtypeofberthAsimplewaytodeterminetheoptimumberthnumber

isbycomparingthetotalexpenses

ofthetwopartiesunderthefollowingthreeconditions:KeeptheberthnumberunchangedLettheberthnumberincreaseoneLettheberthnumberdecreaseoneChapter2Portcapacityandships2.3DeterminationofberthrequirementMathematicalexpressionoftheoptimumberthnumberDenotethedailyexpenseofasingleberthbycb,whichincludestotalinitialinvestmentofthefixedfacilities（固定設(shè)備初投資）maintenanceexpenseoftheport（營運費）Denotethetotaldailyexpenseofashipbycs,whichincludesfixedcosts（固定費用）:

totalinitialinvestmentofthefixedfacilitiesoperationandmaintenanceexpenses（營運費）Thefixedcostsincludestheexpensesofshipfacilities,laborage,stuff(材料),broking(經(jīng)紀(jì)),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（隨機變量）.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

（負(fù)指數(shù)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(泊位閑置損失)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.統(tǒng)計數(shù)據(jù)顯示，多數(shù)港口雜貨船到達(dá)符合泊松分布。Theoccupationtime(servicetime)ofshipsusuallyconformstoErlangdistribution.Insomeports,itconformstonegative-exponential

distribution.船舶在泊位時間（服務(wù)時間）一般愛爾蘭分布。某些港符合負(fù)指數(shù)分布。Thearrivalrateoflinerships(班輪)oftenconformstothesecond-orderErlangdistributionbecauseshipandcargoownersareusuallyfixedandaremoreeasilytobescheduled.Randomnessusuallycomesfromnaturalfactors.So,theE2/E2/Smodeloftengivesmorerationalforecastresults.班輪到船率經(jīng)常符合二階愛爾蘭分布，因為船和貨主一般都是固定的，行程比較容易確定。隨機性主要來自于自然因素。所以，

theE2/E2/S模型經(jīng)常給出合理預(yù)報結(jié)果。Chapter2Portcapacityandships2.4IntroductiontoqueuingtheoryItisimportantfortheplannerstobeawareofthefactthattheforecastedresultsbymathematicalmodelreflectsonlythemosttypicalsituationandisasimplificationofthecomplexpicture.對于規(guī)劃者來說，了解到數(shù)學(xué)模型預(yù)報結(jié)果只是反映了最典型情況和對復(fù)雜實際情況的簡化是很重要的。Sometimesitmaybeoversimplifiedandthustheresultsmaybeunreasonable.有時甚至?xí)蜻^于簡化而使結(jié)果不合理。Inthissense,theforecastedresultsisonlyofvaluesofreferenceratherthanpreciseresults.在這個意義上，預(yù)報結(jié)果只能作為一種參考，而不能認(rèn)定為精確結(jié)果。Chapter2Portcapacityandships2.4Introductiontoqueuingtheory2.5MoreapplicationcasesofqueuingtheoryConceptofberthgroupDuetotherandomfeaturesincargohandlingrateandshiparrivalrate,theservicequalitywilllikelybeimprovedifseveralberthsinaquayaremanagedasaunit(integratively,集中管理)

accordingtothequeuingtheory.Thiscanbeseenclearlyfromthefollowingdiscussions.由于在貨物裝卸及船舶到達(dá)中存在隨機特征，根據(jù)排隊論原理，如果幾個泊位集中管理，服務(wù)質(zhì)量很可能會提高。這可以從以下討論中看出來。Chapter2PortcapacityandshipsExample3StrategyofmanagementCertainporthastwosectionsandeachhastwocontainerberths,respectively.Eachsectionhasthethroughputamountingto500,000TEU/a.TheshipmentisG=1000TEUpership.Theloading/unloadingtime1/m=0.8days/ship.某港有兩個港區(qū)，每個港區(qū)有兩個泊位，每個港區(qū)吞吐量為50萬TEU，每艘船的平均裝載量為1000TEU，裝卸時間為1/m=0.8天/艘。UseM/E2/Smodel(PoissondistributionforshiparrivalandErlangdistributionforservicetime)tocomparetheadvantagesanddisadvantagesofintegrativeandindependentmanagement.用M/E2/S模型（船舶到達(dá)符合泊松分布，裝船時間符合愛爾蘭分布），對比集中和分散管理的優(yōu)缺點。Chapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheoryManagedindependentlyFromTable4-8(textbook),itisinterpolatedshipsperdayChapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheoryManagedasaunitFromTable4-8(textbook),itisinterpolateddaysFromtheresults,wecanseethatalthoughtheequipmentsremainunchanged,thewaitingtimepershipisreducedby:從結(jié)果看出，盡管設(shè)備未變，待泊時間減少了0.244-0.0704=0.174day/shipTheannualamountofsavedtimeis（一年節(jié)約時間）Thecorrespondingexpense

savedperyearis(supposingtheexpenseofwaitingshipstobecb=172000CNY/ship·day):YuanRemarksAlthoughtheresultscannotbeabletoaccountforthecompletesituation,itdoinspireusthatsimilarberthsinaquaymanagedasaunitwillbesuperiortomanagedindependentlyintermsoftheirefficiency.雖然結(jié)果不能說明問題的全部，但給我們的啟示是一個泊位組的相似的泊位綜合管理優(yōu)于分散管理。Chapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheoryAdvantageofincreasingloading/unloading(handling)efficiency提供裝卸效率的好處Inordertocompletetheincreasingthroughputofaport,oneisoftenconfrontedwiththechoiceofwhethertoincreaseberthnumberortoimprovetheefficiencyofeachloading/unloadingequipmentsoastosatisfytheincreaseinportthroughput.為了完成不斷增長的吞吐量要求，我們經(jīng)常面臨選擇增加泊位數(shù)還是提高裝卸效率Byusingthequeuingtheory,thequestioncanbeclarified(闡明)easily.運用排隊論，問題可以得到澄清。Asshowninexample1,tocarryoutthethroughputof146×104tons,onesolutionistobuildanewberthwhilekeepingtheefficiencyofloading/unloadingfacilitiesunchanged.如例1所示，要完成146萬噸的吞吐量，一種方案是新建一個泊位，而裝卸效率不變。Chapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheoryWiththe4berths(3oldonesplus1newly-builtone),theberthutilizationfactorrs=50%andtheratioofwaitingtimetoservicetimeis0.087.Theportnowbecomesmorereadytoprovideserviceforcallingships.4個泊位情況下（3個已有，1個新建），泊位利用率為50%，待泊時間與范圍時間之比為0.087，港口接近隨到隨靠。Isitthebestwaytoincreaseportcapacity?Ifnot,thenwhatwillhappenifweinvestmoreintheloading/unloadingfacilitiesinsteadofinconstructionofanewberth?增加泊位是最好辦法嗎？如果不是，那么如果投到裝卸設(shè)備，而不是建新泊位會怎么樣呢？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;在任何投資實施之前，船舶全部在港時間為最大，因為待泊時間和服務(wù)時間都比改善之前都大。Thewaitingtimeisdecreasedsignificantlyaftertheconstructionofonemoreberth,howevertheservicetimestillremainsunchanged,consequentlythetotaltimeisstillatahighlevel;建成一個泊位后待泊時間顯著減小，但服務(wù)時間不變，因此，總在港時間仍然較大。Chapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheoryByincreasingonesetofloading/unloadingline,i.e.,thehandlingrateisincreasedby50%,boththewaitingtimeandtheservicetimearereducedeffectivelyandthetotaltimegainsminimum;增加一套裝卸設(shè)備后，裝卸效率提高50%，待泊時間和服務(wù)時間都顯著減少，總在港時間也達(dá)到最小。Theexampleindicatesthatimprovementofhandlingrateismoreeffectiveinsavingstaytimethanincreasingberthnumber.

這個例子表明，提高裝卸效率比起增加泊位對于節(jié)省在港時間更有效。Thisiswhymodernportprefersusinghighly-efficientloading/unloadingequipmentstosolelyincreasingberthnumberwhilekeepingusingloading/unloadingequipmentsoflow-efficiency.這就是為什么現(xiàn)代港口大都采用高效率的裝卸機械，而不是靠單純增加泊位數(shù)量，而裝卸機械維持原狀。Chapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheoryHowtoarrangethechanceofimprovingportcapacity

怎樣安排提高港口通過能力的時機Berthutilizationfactorhassignificantinfluenceontheservicequalityofaport.泊位利用率對于港口的服務(wù)質(zhì)量有很大影響Fromtheformula,itcanbeseenthatifthehandlingrate

Randtheberthnumber

Sremainunchanged,theutilizationfactorhastobeincreasedinordertosatisfythedesignatedthroughput.從公式可以看出，如果泊位數(shù)保持不變，為了完成吞吐量，必須提高泊位利用率。RatioofwaitingtimetoservicetimeUtilizationfactorChapter2Portcapacityandships2.5MoreapplicationcasesofqueuingtheoryItcanbeconcludedthatthelowertheutilizationfactoris,thebetterservicequalityaportwillpossess.泊位利用率越低，服務(wù)質(zhì)量越好。Whentheutilizationfactorreachessuchahighdegreeastheservicequalityofaportisseriouslyaffected,const