Wienerbelievedthathisfatherwasabornscholar,whocombinedGermanthought,JewishwisdomandAmericanspirit.Fromchildhoodtoyouth,Wienerhasbeenlivingunderhisinfluenceandhasgraduallygrownintoascholar.
Achildprodigyinthepast
Childhoodtraining
Wienerisatruechildprodigy.Wiener’sfather,Leo,discoveredhisson’stalentveryearly,andhefirmlybelievedintheimportanceofeducationwiththehelpoftheenvironment.Theeducationplanheimplementedfromthebeginningoflearninghasdrivenhisunusualsoninasomewhatruthlessway..
Wienerstartedreadingattheageofthreeandahalf,andhiselementarysciencebooksonbiologyandastronomybecamehisenlightenmentbooksonscience.Fromthenon,hewasenthusiasticanddevotedhimselftoawiderangeofscientifictextbooks.Attheageofseven,hebegantogodeepintothefieldsofphysicsandbiology,evenbeyondthescopeofhisfather'sknowledge.FromDarwin’stheoryofevolution,Kingsley’s"NaturalHistory"tothepsychiatricworksofCharcoalandJannet,fromJulesVerne’ssci-finovelstotheliterarymasterpiecesofthe18thand19thcenturies,thereisalmostnothingDon'tread.
Wienerhasastrongcuriosity,buthisfatherusessystematiceducationashismotto,andthetwocomplementeachother.Wienerstudiedsciencebyhimself,whilehisfatheradheredtoateachingplancenteredonmathematicsandlinguisticswithasternattitude.Wienerhasenduredthisrigoroustrainingextremelywell,andhismathematicshasimprovedsignificantly.
GeneralEducation
LeowasverywiseanddecidedtosendWienertotheMathematicsDepartmentofTuftsCollegeinsteadoflettinghimtaketheriskoftakingtheHarvardUniversity'sstressfulentranceexam.Avoidgettingpeople'sattentiontoomuchbysendingachildprodigytoHarvard.
Intermsofmathematics,Wienerhassurpassedthelevelofafreshmaninuniversity,andthereisnocoursethatcanexactlysuithisrequirements.SohedirectlystudiedGalois'stheoryofequationsfromthebeginning.Leostilloftendiscussesadvancedmathematicswithhisson.Asfarasmathematicsandlinguisticsareconcerned,Wiener'sinterdisciplinarylearningpracticeshavenotchanged.Inthesetworespects,Leoisstillhisstrictteacher.
Wienerhasawiderangeofinterests.Inhisfirstyearofuniversity,physicsandchemistryimpressedhimfarmorethanmathematics.Heisparticularlyinterestedinexperimentsandhasdonemanyelectricalengineeringexperimentswithhisneighbor,Dao.Hetriedtoprovetwoideasinphysics.Oneisanelectromagneticpowderdetectorforradiocommunication,andtheotheristotryoutanelectrostatictransformer.BothofWiener'sideasareexcellent.
Thesecondyear,Wienerwasattractedbyphilosophyandpsychology.Thephilosophicalworkshehasreadfarexceedtherequirementsofthecourse.SpinozaandLeibnizarethetwophilosopherswhohavethegreatestinfluenceonhim.TheloftyethicsoftheformerandtheversatilityofthelatterhavealloverwhelmedWiener.HealsogreedilyreadJames'philosophicalmasterpiece,andthroughhisfather'srelationship,hegottoknowthepragmatistmaster.
Inthesameyear,Wienerfocusedonbiologyagain.Biologymuseumsandlaboratorieshavebecomehismostattractiveplaces,andthecaretakeroftheanimalbreedingroomhasbecomehisparticularlyclosefriend.Wienerisnotonlyhappytocollectbiologicalspecimens,butoftenspendsmostofhistimeinthelaboratorylibrary,wherehereadstheworksofthefamousbiologistBatesonandothers.
Wienercompletedtheuniversitycourseinthreeyearsandgraduatedinthespringof1909.Afterthat,hebegantostudyforaPhDinBiologyattheHarvardUniversityGraduateSchool.Wienerchangedhischaracternotbecauseheknewhecoulddoit,butbecausehewantedtodoit.Sincechildhood,hehaslongedtobecomeabiologist.However,Wiener'sexperimentalworkunfortunatelyfailed.Hehaspoorhands-onskills,lackstheskillsandpatiencenecessaryformeticulouswork,anddeepmyopiaaddstothetrouble.
Underthearrangementofhisfather,hetransferredtoCornellUniversitytostudyphilosophy,andreturnedtoHarvardthefollowingyeartostudylogicandlogic,andreceivedaPhDinphilosophyfromHarvardUniversityattheageof18.
TheinterdisciplinaryeducationthatWienerreceivedattheuniversitypromotedthehorizontaldevelopmentofhistalentsandlaidthefoundationforalargenumberofdevelopmentsandtransplantsonvariousinterfacesinmanyfieldsinthefuture.Frommathematicstobiologytophilosophy,thisisactuallythepathWienerhasexperiencedthroughouthisscientificcareer.
Educatedbyfamousteachers
InthelastyearofHarvard,Wienerappliedforatravelscholarshipfromtheschoolandwasapproved.HehasstudiedattheUniversityofCambridgeinEnglandandtheUniversityofGottingeninGermany,studyinglogicandmathematicsundertheguidanceoffamousmathematicianssuchasRussell,Hardy,andHilbert.
RussellisWiener’smainmentorandfriend.Wienerstudiedmathematicallogicandphilosophyofscienceandmathematicswithhim,andgainedmanyprofoundlessonsfromthismaster.Wienerfeltveryfreshandinspiringforhisphilosophycoursesandmathematicalprinciplescourses.Russell'slecturewasclearandclear,likeanunparalleledmasterpiece,whichimpressedhimdeeply.
RussellsuggestedthatWienerreadthethreepaperspublishedbyEinsteinin1905tolearnRutherford’selectronictheoryandBohr’stheory.Russellhasakeensenseofsmellforimportantdiscoveriesinphysics,andhisteachingmadeWienerfirmlyrememberthatnotonlymathematicsisimportant.Andalsoneedtohaveaphysicalconcept.
AlthoughWiener'sphysicsfoundationatthetimewasdifficulttolearnthelatestelectronictheory,Russellencouragedhimtostudy.Wienerlaterchosetocombinemathematicswithphysicsandengineering,whichwasinseparablefromRussell'senlightenment.OneofEinstein'spapersdiscussedBrownianmotion.ItwasonthissubjectthatWienermadeimportantmathematicalresultsinthefollowing10years.
ForWiener’sfuturecareerasamathematician,Russell’sotherimportantinfluenceisthatheproposedtoWienerthatapersonwhospecializesinmathematicallogicandmathematicalphilosophyshouldbestunderstandsomemathematics.Therefore,WienertookmanymathematicscoursesandacceptedtheguidanceofHardyandothers.Hardy'sclear,interestingandthought-provokingspeech,involvingthebasisofrealvariablefunctionsincludingLebesgueintegralsandintroductiontocomplexfunctions,gaveWienerprofoundenlightenmentanddirectlyledtothemainachievementsofhisearlycareer..WienercalledHardyhisidealmentorandrolemodel.
WeineroriginallyplannedtofinishthisyearinCambridge,butRussellisgoingtogivelecturesatHarvardinthesecondsemester.HeadvisedWienertogototheUniversityofGöttingentostudyforHilbertandLandau.course.
WienertookaclassongrouptheorybyProfessorLandauandstudieddifferentialequationsundertheguidanceofHilbert.Hilbertrepresentsthegreattraditionofmathematicsatthebeginningofthiscentury,andistheonlytrulyproficientmathematicianWienerencountered.Hehasabroadfieldofvisionandisgoodatcombininghisextraordinaryabstractabilitywitharealisticunderstandingofphysicalreality.HebecamethemathematicianWienerlongedfor.
TheeducationhereceivedinGöttingenhasbenefitedWienerthroughouthislife.Fromthefamousmathematicsteacher,herecognizedthepowerofscienceandthedepthofknowledge,andforthefirsttimeobtainedtheexperienceofworkingintensivelyandenthusiastically.CambridgeandGöttingenmarkedthebeginningofWiener'sgrowthfromachildprodigytoayoungmathematician.
PersonalLife
NorbertWiener,thecreatorofcybernetics,calledhimselfachildprodigyinhisearlyyears.HisfatherwasaHarvardprofessor.HeoncetookhimtotheUKtomeetRussell,butRussellDon'tlikethiskidandhisfather.
Wiener’swife,Margaret,wasaNazi.DuringWorldWarII,theEnglishversionofHitler’s"MyStruggle"washiddenathome.Atthattime,theirdaughterBarbarawasinelementaryschoolandreadthebookconsciouslyorunconsciously.Sheactuallyquotedthe"aphorism"inthebookwhenshewaswritingandwasalmostexpelledfromschool.
FalloutwithPitts
Theoriginalarticlethatsimulatesneuralnetworkswaspublishedin1943.Bothauthorsarelegends,McCullochandPitts.).MargaretoncetoldWienerthatsomeoneinMcCarrocco'steam(perhapsalludingtoPitts)seduceherbabygirlBarbara,Wienerwasfurious,andimmediatelycutoffallcontactwithMcCullochandhisstudents.NowitseemsthatMargueriteisdeliberatelyspreadingrumors.ButWiener'sactionscausedgreattraumatoPitts.PittswasoriginallyaspecialstudentofWiener,butitisestimatedthathesufferedsetbackswhenhewasyoung,andhistemperamentwasstrange.AfterfallingoutwithWiener,herefusedthegraduatedegreegiventohimbyMITandwasdisheartenedwithknowledge.PittsdiedafewmonthsearlierthanhiselderMcCullochin1969,attheageofforty-six.
Publishingbooks
Modernmasters
In1913,attheageof19,WienerpublishedapaperonsettheoryintheProceedingsoftheCambridgePhilosophicalSociety.Thisisapaperthatsimplifiesthetheoryofrelationstothetheoryofclasses,anditoccupiesaplaceinthedevelopmentofmathematicallogic.Wienerenteredhisacademiccareer.Inthesameyear,hewontheBowdoinPrizefromHarvardUniversityforaskepticalphilosophicalessay"ThePerfection".Beforeturningtothefieldoffunctionalanalysis,Wienerpublished15papersonlogicandphilosophy.
In1918,WienergainedabetterunderstandingofmodernmathematicsbystudyingthemathematicsleftbyGreen,adoctorofmathematicswhopassedaway.Hebegantolookforproblemsworthyofconcentrationinthefieldofmathematics.AlthoughWienerisachildprodigy,asamathematician,hehasbeenlate.
Wienerbegantobeattractedbyfunctionalanalysisanddeterminedtodevotehislifetoit.In1919,Barnett,ayoungmathematicianattheUniversityofCincinnati,paidavisittohim.Wieneraskedhimtorecommendasuitableresearchtopic.HeaskedWienertopayattentiontotheintegralprobleminthefunctionspace.ThissuggestionhadasignificantimpactonWiener'ssubsequentmathematicalresearch.
Inthesummerofthesameyear,duetotherecommendationofOsgood,thedeanoftheMathematicsDepartmentofHarvardUniversity,WienerwenttoteachintheDepartmentofMathematicsatMIT,whereheworkeduntilretirement.
In1920,WienerparticipatedintheInternationalConferenceofMathematiciansforthefirsttime.Beforetheconference,theyworkedtogetherforsometimeattheinvitationofFrecher.WienertriedtopromoteFrecher'sworkandproposedtheBanach-Wienerspacetheory.HerealizedthathisworkontheBrownMovementwasapromisingstart,sohewasmoreenergeticandmoreopen-minded.
In1924,Wienerwaspromotedtoassistantprofessorandin1929asassociateprofessor.DuetohisoutstandingachievementsingeneralizedharmonicanalysisandTauber'stheorem,hewaspromotedtofullprofessorin1932.
In1933,WienersharedwithMorsetheBocherPrizeoftheAmericanMathematicalSocietyforhisworkonTauber'stheorem.Ataboutthesametime,hewaselectedamemberoftheNationalAcademyofSciences.Afterhelearnedaboutthenatureofthisseniorscientificofficialorganization,hewasveryboredandsoonresignedfromhisposition.
OneofthehonorsusuallygiventoasuccessfulAmericanmathematicianistoaskhimtowriteabookfortheAmericanMathematicalSociety'sSeminarSeries.Inthesummerof1934,WienerwasinvitedtowritetheFourierTransformintheComplexDomain.Soon,hewaselectedasthevicepresidentoftheAmericanMathematicalSociety.Itwasonlybecausehedidnotliketobeinadministrativepositionsthathewassparedfrombeingelectedaspresident.
Beginninginthe1930s,WienerpaidattentiontotheanalogcomputersstudiedbyBush.From1935to1936,hewasinvitedtoChinaasavisitingprofessor.IncooperationwithLiYurongatTsinghuaUniversity,heresearchedanddesignedaverygoodelectronicfilterandobtainedthepatentfortheinvention.WienertookhisyearinChinaasaspecificmilestoneinhisacademiccareer,thatis,asademarcationpointbetweenacraftsmanwhohasjustcompletedhiscareerinscienceandamasterinthisindustrytosomeextent.
DuringtheSecondWorldWar,Wieneracceptedaresearchworkrelatedtofirecontrol.Thisproblempromptedhimtoexploreindepththecomputationalfunctionsofusingmachinestosimulatethehumanbrain,establishpredictiontheoryandapplyittothepredictiondeviceoftheairdefensefirecontrolsystem.In1948,Wienerpublished"Cybernetics",announcingthebirthofthisemergingdiscipline.Thisisthegreatscientificachievementofhislong-termhardworkandmultilateralcooperationwithphysiologistRosenbrütteandothers.Wienerimmediatelyjumpedfromamathematicianwithalimitedreputationtoaninternationalcelebrity,whenhewasalreadyoverhalfahundredyearsold.Sincethen,Wienerhascontinuedtomakeoutstandingcontributionstothedevelopmentandapplicationofcybernetics.
In1959,WienerretiredfromtheMassachusettsInstituteofTechnology.InJanuary1964,hewasawardedbythePresidentoftheUnitedStatesforhis"avarietyofamazingcontributionsinpuremathematicsandappliedmathematicsandthecouragetogodeepintoengineeringandbiologicalsciences,aswellasfar-reachingpioneeringworkinthesefields."NationalMedalofScience.
WienerisaresearcheroftheJacqueshamFoundationinEurope,aFulbrightresearcher,amemberoftheMathematicalSocietyofBritain,Germany,Franceandothercountries,andhasservedasavisitingprofessorinChina,India,theNetherlandsandothercountries.
PersonalAchievements
Overview
Duringhis50yearsofscientificcareer,Wienerhasbeeninvolvedinphilosophy,mathematics,andphysics.Andengineering,andfinallyturnedtobiology,andachievedfruitfulresultsinvariousfields.ItcanberegardedasthemultitalentedandknowledgeablescientificgiantpraisedbyEngelsinthiscentury.Hehaspublishedmorethan240papersand14booksinhislifetime.Hismainworksare"Cybernetics"(1948),"WienerAnthology"(1964)and"WienerMathematicsEssays"(1980).Wieneralsohastwoautobiography"TheChildProdigyinthePast"and"IAmaMathematician".
Hismainresultshavethefollowingeightaspects:
EstablishingWienerMeasure
WieneristhefirsttolearnfrommathematicsAmathematicianwhostudiesBrownianmotiondeeply.In1921,heusedpointsinthefunctionspacetorepresentthepathsofparticlesinBrownianmotion,andprovedthatallthesepaths,exceptforthesetofprobabilityO,arecontinuousbutnotsmooth,thatis,almostindifferentiableeverywhere.HeusedLebesgueintegralstocalculatetheaverageofthefunctionsonthesepaths.In1923,Wienergaveastrictdefinitionofrandomfunctionforthefirsttime,provingthatitcouldbeatheoreticalmodelofBrownianmotion.Startingfromtheconceptofsampledistance,Wienerstudiesthecollectionof"paths",introducesWienermeasures,andrevealsthephysicalcharacteristicsofcontinuousandindifferentiablefunctions,soBrownianmotionisalsocalledWienerprocess.
Wiener'sworkisextremelyfruitfulforprobability.Itnotonlybreathesnewlifeintooldproblems,butmoreimportantly,opensupnewresearchfields,revealingthestrikingconnectionsbetweenprobabilitytheoryandotherbranchesofmathematics.Wiener’sresearchcanbesaidtobeapioneeringworkinmodernprobabilitytheory.NowameasurethatdescribesBrownianmotiondefinedinthecontinuousfunctionspaceiscalledtheWienermeasure,andtheintegralaboutthismeasureiscalledtheWienerintegral.Later,JapanesemathematicianItoKiyoshidevelopedtherandomintegraltheoryonthisbasis.
IntroductionofBanach-Wienerspace
In1920,WienerextendedtheFrenchmathematicianFreche’sgeneraltheoryoflimitsanddifferentiationtoVectorspace,andgivesacompletesetofaxioms.Wiener’sresultscoincidedwithBanach’spaperpublishedinthePolishJournalofMathematicsafewweekslater,andthegeneralizationwasnotbad.BanachconceivedandpublishedhistheoryseveralmonthsearlierthanWiener,butthedegreeofindependenceofthetwoisthesame.Therefore,thesetwoworkswereoncecalledBanach-Wienerspacetheory.Wienercontinuedtopublishresultsinthisareainashortperiodoftime,whichprovidedthebasisforvonNeumann's1927HilbertspaceandtheaxiommethodofoperatorsinHilbertspace.
Later,Wienergraduallyleftthisfield,buthispioneeringworkonfunctionalanalysis,anewbranchofmathematicsthatemergedandflourishedinthe20thcentury,hasbeenrecordedinthehistoryofmathematics.
Explainthepotentialtheory
From1923to1925,Wienermadebasiccontributionstothepotentialtheory.FortheDirichletproblemofagivencontinuousboundaryvaluefunction,theexactgeneralizedgroupisobtained.Forgeneralcompactsets,theconceptoftoleranceisdefined,andthewell-knowncriterionofregularityisgiven.Theearlierconceptoftheelectromagneticpotentialinsidearegionbelievedthatitshouldbeexactlythesameasthevaluesgivenontheboundary.
Wienerfollowstheconceptsimilartogeneralizedintegralsthathehasstudied,andnoticesthatthepotentialinsidearegioncanberegardedasdeterminedbythelinearcombinationofthepotentialsaroundtheboundary,evenifitisclosetoTheboundarypointcannotgiveacontinuousfunctionboundary.Thisisabrand-newconcept,Wienerthusgreatlyexpandedmanyconceptsofpotentialtheory,includingtheconceptsofchargeandcapacitance.
Thesignificanceofthisresultisthatthenewtheorybelievesthattherelationshipbetweenthepotentialofaninteriorpointandtheboundaryvalueisageneralizedintegral,ratherthanacombinationoftheseinternalpotentialsandthepotentialontheboundary.Thelimitprocess.Thisreversestheoriginalviewontheborderissue.Justastherehavebeenmanyinversionsinmathematics,thereformulationofpositiontheoryhasblownintoafreshairofasituationthathasbeenlifelessformanyyearsbyanoverlyconservativeargument.
DevelopingHarmonicAnalysis
InordertoestablishasolidlogicalfoundationfortheHeavisidecalculationmethod,WienerembarkedonanewpathofHarmonicAnalysis.Atthebeginningof1926hepublishedhisfirstpaperonthissubject,andhisworkforthenextfiveyearsculminatedinalongarticleofgeneralizedharmonicanalysis.Wienerborrowedfunctionsfromphysicsasthekeytoharmonicanalysis,andthenlinkeditwithcommunicationtheoryandwroteitasFouriertransform.Heobtainedwhatisnowcalledthestateofspectraldistribution.Inordertoproveoneofthekeyformulas,WienerproposedapowerfulandhighlyoriginalmethodinHardyandLittlewood'sTaubertheorem,namelythefamousinversiontheoremofnon-zeroabsoluteconvergenceFourierseries.Thisisanamazingexampleofunifiedmathematicalabstraction.Wiener'sachievementsinthisarealaterbecamethebasisofBanach'salgebratheory,andderivedresultssuchastheprimenumbertheorem.
DiscoveringtheWiener-Hopfmethod
around1930.WienerandastronomerHopfcooperatedtostudyaclassofsingularintegralequationswithdifferencekernelsgivenonasemi-infiniteinterval.ThistypeofequationisnowcalledtheWiener-Wipffequation.WienerextendedHopf'sresearchonradiationequilibrium,andobtaineditssolutionin1931.Thebasicideaistotransformtheoriginalequationintoafunctionalequationthroughintegraltransformation,andthenusethefunctionfactorizationmethodtosolveit.Therefore,theWiener-Hopfmethodisalsocalledthefactorizationmethod.Ithasbecomeacommonmethodforstudyingvariousmathematicalandphysicalproblems.
WienercreativelystatedthatthemoststrikingapplicationoftheWiener-Hopfequationisthattheboundarybetweenthetwoprocessesistimeratherthanspace,whichisexactlywhatpredictstheoryAveryappropriatetoolthatcanbeappliedinsomeways.Hefurtherpointedoutthattherearemanymoregeneralproblemsaboutinstrumentresearchthatcanbesolvedwiththistime-basedtechnique.Afterthe1940s,thetheoryofthisequationhasbeensystematicallydevelopedonthebasisofanalyticfunctionboundaryvalueproblems,harmonicanalysisandoperatortheory.Itsapplicationhasalsoexpandedfromradiationproblemstomanyotherfields,suchasneutronmigrationandelectromagneticwavediffraction.,Cybernetics,multi-bodyproblemandentrancetheory,etc.
ProposedWienerfiltertheory
DuringWorldWarII,inordertosolvetheproblemsofairdefensefirecontrolandradarnoisefiltering,WienerusedacomprehensiveInhispreviouswork,inFebruary1942,hefirstgaveouttheWienerfilterformulaforinferringthefuturefromthepastdataofthetimeseries,andestablishedtheWienerfiltertheorythatpushesthetimeseriesoutoftheforecastundertheminimummeansquareerrorcriterion..
ThisworkofWienerprovidesatheoreticalbasisforthedesignofautomaticairdefensecontrolartilleryfireandotheraspectsofpredictionproblems,andopensupatheoreticalwayforevaluatingtheefficiencyandqualityofprocessinginformationofacommunicationandcontrolsystem.Ithasanimportantinfluenceonthescienceofautomationtechnology.Wienerintroducedstatisticalfactorsintheproblemandusedautocorrelationandcross-correlationfunctions,whichprovedtobeextremelyimportant.TheWienerfiltermodelwasgeneralizedinthe1950stoonlyobservestationaryprocessesinalimitedtimeintervalandsomespecialexternalstationaryprocesses.Itsapplicationrangehasalsobeenexpandedtomorefields.Itisstilldealingwithvariousdynamicdata.(Suchasmeteorology,hydrology,seismicexploration,etc.)andoneofthepowerfultoolsforpredictingthefuture.
CreateWienerInformationTheory
Wienerisoneofthefoundersofinformationtheory.Hestudiedinformationtheoryfromthecircuitwithdirectcurrentoratleastcanberegardedasdirectcurrent,independentofShennong,introducedstatisticalmethodsintocommunicationengineering,andlaidthetheoreticalfoundationofinformationtheory.Wienerregardsmessagesasatimeseriesofmeasurableevents,andcommunicationasastatisticalproblem,whichisstudiedmathematicallyasastationaryrandomprocessanditstransformation.Heclarifiedtheprinciplesandmethodsofquantificationofinformation,similarlyused"entropy"todefinetheamountofinformationinacontinuoussignal,andproposedtheShennon-Wienerformulatomeasuretheamountofinformation:aunitofinformationisachoicebetweentwoequalconcepts.Theinformationconveyedwhenonethingmakesasinglechoice.
ThesepioneeringworkofWienerstronglypromotedthecreationofinformationtheoryandopenedupbroadprospectsfortheapplicationofinformationtheory.Shannon,thefounderofinformationtheory,said:"ThegloryshouldbeattributedtoProfessorWiener."
Thecreationofcybernetics
Wiener’sgreatestcontributiontothedevelopmentofscienceisthecreationofcybernetics.Thisisafringedisciplineformedbylinkingmathematicstoresearchauto-regulation,communicationengineering,computerandcomputingtechnology,andneurophysiologyandpathologyinbiologicalsciencesandotherdisciplinesofcommonconcern.
InOctober1947,Wienerwroteanepoch-makingbook"Cybernetics",whichbecamepopularintheworldimmediatelyafteritwaspublishedin1948.Wiener'sprofoundthoughtsarousedpeople'sgreatattention.Itrevealsthecommonlawsofthecommunicationandcontrolfunctionsofthemachineandthehumannerveandsensoryfunctions;itprovidesanewscientificmethodformodernscienceandtechnologyresearch;itbreaksthroughtheshacklesoftraditionalthinkinginmanyways,andeffectivelypromotesmodernscience.Aseriesofchangesinthewayofthinkingandcontemporaryphilosophicalconcepts.
Now,therehavebeenmanymajordevelopmentsincybernetics,butWiener'sideaofusingGibbsstatisticalmechanicstodealwithcertainmathematicalmodelsisstillatthecenter.Hedefinedcyberneticsas:"Therearetwostatevariables,oneofwhichcanbeadjustedbyus,andtheothercannotbecontrolled.Atthistime,theproblemwefaceishowtousetheinformationoftheuncontrollablevariablefromthepasttothepresentToproperlydeterminetheoptimalvalueofthevariablethatcanbeadjustedtoachievethemostsuitableandbeneficialstateforus."
Cybernetics
Overview
Thebirthofcyberneticsisoneofthegreatestscientificachievementsofthe20thcentury.Manynewconceptsandnewtechnologiesinmodernsocietyarecloselyrelatedtocybernetics.Cyberneticsistheproductofmutualpenetrationofmultipledisciplinessuchasautomaticcontrol,electronictechnology,radiocommunication,computertechnology,neurophysiology,mathematicallogic,language,etc.Ittakesthecharacteristicsofcommunicationandcontrolcommontovarioussystemsastheresearchobject.Regardlessofwhetheritisamachine,alivingorganism,orevenasociety,althoughtheyaresystemsofdifferentnature,theyalladjustanddeterminetheirownmovementsaccordingtocertainchangesinthesurroundingenvironment.ThefounderofcyberneticsistheAmericanmathematicianNorbertWiener(NorbertWiener,1894~1964).
In1948,hepublishedhisfoundationalwork"Cybernetics",markingthebirthofthisemergingedgediscipline.Thesubtitleofthebookis"TheScienceofControlorCommunicationinAnimalsorMachines",whichishisdefinitionofcybernetics.ThetermcyberneticscomesfromtheGreekwordkubernan,whichoriginallymeanssteersman,whichmeans"helmsman",anditmeans"manager'sart".
Informationfeedbackissuesraised
Inthe1930sand1940s,peoplehadadeeperunderstandingofinformationandfeedback,Somefamousscientistshavedonealotofresearcharoundinformationandfeedback.BritishstatisticianRonaldAylmerFisher(1890~1962)studiedinformationtheoryfromtheperspectiveofclassicalstatisticaltheoryandraisedtheissueofunitinformation;AmericantelecommunicationsengineerShannon(ClaudeElwoodShannon,1916~2001)studiedinformationtheoryfromtheperspectiveofcommunicationengineering.Fromtheangleofview,theproblemoftheamountofinformationwasstudied,andtheformulaofinformationentropywasproposed;Wienerstudiedtheproblemofnoisysignalprocessingfromtheviewpointofcontrol,establishedtheWienerfilteringtheory,andanalyzedtheconceptofinformation,andproposedthemeasurementoftheamountofinformation.Theessenceoftheformulaandinformation.Theysolvedthemeasurementproblemofinformationalmostsimultaneously.Duringthisperiod,peoplegraduallyunderstoodtheworkingprincipleofthefeedbackcontrolsystem.In1932,theAmericancommunicationsengineerHarryNyquist(HarryNyquist1889~1976)discoveredthestabilityconditionofthenegativefeedbackamplifier,whichisthefamousNyquiststabilitycriterion.In1945,Wienerextendedtheconceptoffeedbacktoallcontrolsystems,andunderstoodfeedbackastheprocessofextractingpartoftheinformationfromtheoutputofthecontrolledobjectasthenextinput,therebyaffectingthere-output.Pavlov'sconditionedreflextheoryalsoprovesthattherearealsoinformationandfeedbackproblemsinlivingorganisms.
Wiener'scooperationwithothers
WhenWienerwasimprovingairdefenseweapons,hediscoveredthatthecoreissueofcontrolandcommunicationinanimalsandmachinesisinformationandinformation.Transmissionandinformationprocessing.WienerandAmericanneurophysiologistArturoRosenblueth(ArturoRosenblueth,1900~1970)workedtogetheronthissubjectformorethan10years(1934~1947).RosenbloswasaMexican,andwasacolleagueandcollaboratorofProfessorWalterBradfordCannon(1871~1945),afamousphysiologistatHarvardMedicalSchoolatthetime,andhewashighlyregardedbyCannon.Inthe1930s,Rosenbruceheldmonthlyseminarsonscientificmethods.WienerwasalsoworkingatHarvardMedicalSchoolatthistime.WienerandmanyyoungscientistsfromHarvardMedicalSchool,includingexpertsinvariousfieldssuchasmathematics,physics,electronics,engineering,physiology,psychology,andmedicine,allparticipatedintheseminar.AseminarledbyBlues.Theygatheraroundaroundtableeverytimeandtalkfreelytogetherwithoutrestraint.Afterthemeal,amemberoftheircollective,oraninvitedguest,readoutapaperonacertainscientificissue,usuallyapaperonmethodologicalissues.Announcementreadersmustendureasharpcriticism,criticismiskind,butmerciless.Thisisreallyagoodlaxativeforthosewhoarehalf-thinking,thosewhohaveneverfullyself-criticized,thosewhoareoverconfidentandarrogant,andthosewhocan'tstanditwillnotcomenexttime.However,manyoftheseregularvisitorstodinnersandseminarsfeelthattheyhavebenefitedalot,andtheyhaveanimportantandlastingroleinpromotingthedevelopmentofscienceandtechnology.
WienerandRosenbrucehavelongrecognizedthatthedevelopmentofmodernscienceandtechnology,ontheonehand,hasincreasinglybecomeacareercarriedoutbyspecialistsinanincreasinglynarrowfield,whichhasreducedsomescientiststonarrow-mindedfields.Aslavetothedivisionoflabor;ontheotherhand,thereisatrendofcross-overandintegrationofvariousdisciplines,andmanyproblemsthatneedtobestudiedjointlybyalldisciplineshavebeenraised.Thisisinsharpcontradictionwiththeoriginalnarrowprofessionaldivisionoflabor.Howtoresolvethesecontradictions?Theybelievethatitisthesemarginalareasofsciencethatprovidethemostabundantopportunitiesforeducatedresearchers.Inotherwords,aslongastheoriginalnarrowprofessionaldivisionoflaborisbroken,agroupofexpertswhoareexpertsinhisownfieldbutalsohavemoreknowledgeofhisneighboringfieldsshouldbegathered.Forexample,letmathematicians,mathematicallogicians,andphysiologistscomeintocontactwithengineering,andletengineersfamiliarizethemselveswithphysiology.Inthisway,toexplore,cultivateandcultivatetheundevelopedscientificvirginlandcangetthegreatestscientificgains.
Wienerhimselfalsosaid:Intheabove-mentionedjointwork,amathematician(heisamathematician)doesnotneedtohavetheabilitytoleadaphysiologicalexperiment,butheneedstounderstandandcriticizeaphysiologicalexperiment.Andtheabilitytosuggestotherstoconductanexperiment;aphysiologist(Rosenblousisaphysiologist)doesnotneedtohavetheabilitytoproveamathematicaltheorem,butmustbeabletounderstandthephysiologicalsignificanceofthemathematicaltheorem,andbeabletotellthemathematicianthatheshouldTofindsomething.
ThescientificseminaronbraininhibitionheldbytheMasseyFoundationinMay1942proposedthatthewell-developedconceptsandmethodsofinformationandfeedbackinthefieldsofcommunicationengineeringandcontrolengineeringmayhelpNeurophysiologicalresearch.Atthistime,theideaofcyberneticshasbeenformed,butithasnotbeenofficiallynamed.Attheturnof1943~1944,ascientificseminaroncyberneticthoughtwasheldinPrinceton,whichfurtherconfirmedthecyberneticthoughtandbelievedthatthereisacommonideologicalfoundationamongworkersindifferentfields,andonescientificfieldcanuseanotherscientificfield.Morematureconceptsandmethodsdeveloped.Between1946and1953,theMasseyFoundationinitiatedaseriesofscientificseminarsonfeedbackissues,whichgreatlypromotedthedevelopmentofcybernetics.
TheformalproposalofWienerCybernetics
Wienercapturesthecommonfeatureofallcommunicationandcontrolsystems,thatis,theyallcontainaninformationtransmissionAndtheprocessofinformationprocessing.Hepointedout:Acommunicationsystemalwaystransmitsinformationofvariousideologicalcontentaccordingtopeople'sneeds,andanautomaticcontrolsystemmustadjustitsownmovementaccordingtothechangesinthesurroundingenvironment,withacertaindegreeofflexibilityandadaptability.Theinformationreceivedbythecommunicationandcontrolsystemhasacertainrandomnatureandhasacertainstatisticaldistribution.Thestructureofthecommunicationandcontrolsystemitselfmustalsoadapttothisstatisticalnature,andbeabletomakeastatisticalanalysisoftheinputexpectedtobereceived.Statisticallysatisfactoryaction.Wienerandhiscollaboratorsfinallysucceededincreatingthebrand-newdiscipline"Cybernetics"in1947.Thefollowingyear,thebook"Cybernetics"waspublished,whichattractedwideattentionfrominternationalacademiccircles.
InadditiontoWiener,theparticipantsofthemethodologicaldinnerpartylatermadetheirownachievements:Rosenbruswasalsooneofthepioneersofcyberneticsandartificialintelligence;vonNeumann(JohnvonNeumann,1903~1957)becamethefounderofgametheoryandoneofthefoundersofbinaryelectroniccomputers;JulianHimelyBigelow(1913~2003)wastheearliestparticipantinthedesignofelectroniccomputers;WarrenSturgisMcCulloch,1898~1969)andPitts(WalterPitts,1923-1969)becamethefoundersofneuralcyberneticsandartificialintelligence.Factshaveprovedthatitistheseyoungscientistswhohaveobtainedthegreatestgainsinthe"neglectednoman'slandbetweenthevariousestablisheddepartments"andgreatlyenrichedanddevelopedscience.
Thecontributionofcybernetics
Forphysiology,thecontributionofcyberneticsishuge.Themostprominentistheintroductionoffeedbackideasfromengineeringconceptsintobiologicalsystems.Greatlyenrichedanddevelopedphysiology.Theconceptof"constantinternalenvironment"putforwardbyClaudeBernerinthelastcenturywasthendevelopedbyCannonintothehomeostasistheory,becomingoneofthebasicmodernconceptsinlifesciences,anditssignificanceissignificant;butIfthereisnofeedbackautomaticadjustmentmechanism,itwillbecompletelyincredible.
ApplicationofCybernetics
In1949,AmericanendocrinephysiologistRoyGrahamHoskins(1880~1964)respondedtoWiener’ssuggestion,Firstintroducedtheconceptoffeedbackintotheendocrinefield,andpointedoutthatthereisafeedbackmechanismbetweenthethyroidandthepituitary.In1956,Sweden'sUlfSvonEuler(UlfSvonEuler,1905~1983)injectedasmallamountofthyroxineintotheanteriorpituitary,whichreducedtheradioactiveiodinereleasedbythethyroidgland,thusfurtherconfirmingthatnegativefeedbackisthepreciseregulationofbodyfunctions.Anindispensableandimportantlink.
PersonalInterests
Thefamous20th-centurymathematicianNorbertWiener,whowasveryintelligentsincechildhood,wasabletoreadandwriteattheageofthree,andgraduatedfromcollegeattheageoffourteen.Afewyearslater,hepassedhisdoctoralthesisdefenseandbecameadoctorofscienceatHarvardUniversityintheUnitedStates.
Duringtheawardingceremonyofthedoctoratedegree,theexecutivechairmanwassurprisedtoseeWienerwithachildishlook,soheaskedhisagefacetoface.Wienerdeservestobeamathematicsprodigy.Hisanswerisveryclever:"Thecubeofmyagethisyearisafour-digitnumber,andthefourthpowerofmyageisasix-digitnumber.Thesetwonumbersjustputthetennumbers0,1,2,3,4,5,6,7,8,and9areallused,notheavyandnotmissing.Thismeansthatallthenumbersarebowedtome.IwishIwillbeabletodosomethingearth-shatteringinthefieldofmathematicsinthefuture.Career."
WhenWienersaidthis,allfourwereshocked,andeveryonewasdeeplyattractedbyhiswonderfulquestion.Peopleinthewholemeetingweretalkingabouthisage.
Infact,thisquestionisnotdifficulttoanswer,butitrequiresabitofdigital"inspiration."Itisnotdifficulttofindthatthecubeof21isafour-digitnumber,andthecubeof22isalreadyafive-digitnumber,soWiener’sageisatmost21yearsold;bythesametoken,thefourthpowerof18isasix-digitnumber,andthefourthpowerof17isafour-digitnumber.Thepowerisfivedigits,soWiener'sageisatleast18yearsold.Inthisway,Wiener'sagecanonlybeoneofthefournumbers18,19,20,and21.
Theremainingworkis"selectonebyone".Thecubeof20is8000,andthereare3repeateddigits0,whichisnotsuitableforthetitle.Inthesameway,thefourthpowerof19isequalto130321,andthefourthpowerof21isequalto194481,bothofwhicharenotsatisfactory.Intheend,thereisonlyone18left.Isitthecorrectanswer?Checkthecalculations,thecubeof18isequalto5832,andthefourthpowerisequalto104976,whichhappenstohaveuseduptenArabicnumerals"notheavyandnotmissing",whataperfectcombination!
This18-year-oldyoungPh.D.didagreatjoblater:hebecametheforerunnerofinformationtheoryandthefounderofcybernetics.