热电现场处置方案1汇总

Session7CellularAutomataJuanLiCommunicationsLaboratory,HUTFirstbeginningwithintroductiontothehistoryofcellularautomata,thispaperpesentsseveralimportantideasinthisfield.Thenabriefanalysisof1-Dcellularautomataisgiven.Finally,somemoreadvancedapplicationsofcellularautomataaredemonstrated.7.1IntroductionTheincreasingprominenceofcomputershasledtoanewwayoflookingattheworld.Thisviewseesnatureasaformofcomputation.Thatis,wetreatobjectsassimplecomputers,eachobeyingitsownsetoflaws.Acomputerfollowsrules.Ateachmoment,therulesdetermineexactlywhatthecomputerwilldonext.Wesaythatacomputerisanexampleofanautomaton.Other,simplerexamplesofautomataalsoexist1.Thesemoreabstractrule-followingdevicescanbeeasiertostudyusingcomputers,andtheycanbeinterestingtostudyintheirownright.Onetypeofautomatonthathasreceivedalotofattentioniscellularautomata.Foronething,they1Automataisthepluralofautomaton.Whiletheword“automaton”conjuresuptheimageofamechanicaltoyorasoullessorganism,incomputerscienceithasaveryprecisemeaning.Itreferstoallmachineswhoseoutputbehaviourisnotadirectconsequenceofthecurrentinput,butofsomepasthistoryofitsinputs.Theyarecharacterisedashavinganinternalstatewhichisarepositoryofthispastexperience.Theinnerstateofanautomatonisprivatetotheautomaton,andisnotavailabletoanexternalobserver.7374Session7.CellularAutomatamakeprettypictures.Foranother,theyarerelatedtoexcitingnewideassuchasartificiallifeandtheedgeofchaos.Forafairlysimpleexamplesee[1].The“cellularautomaton”providesawayofviewingwholepopulationsofinteracting“cells”,eachofwhichisitselfacomputer(automaton).Bybuild-ingappropriaterulesintoacellularautomaton,wecansimulatemanykindsofcomplexbehaviours,rangingfromthemotionoffluidsgovernedbytheNavier-Stokesequationstooutbreaksofstarfishonacoralreef.7.2HistoryofCellularAutomata7.2.1SpectacularhistoricalautomataTheearliestautomataweremechanicaldevicesthatseemedtodemonstratelifelikebehaviour.Theytookadvantagenotonlyofgears,butalsoofgravity,hydraulics,pulleysandsunlight—theeffectcouldbedazzling,aswiththeextraordinaryclockofBerne:Createdin1530,thismassivetimepiecehourlydisgorgedadazzlingpageantryofautomatafigures,beginningwithacrowingcockandfollowedbyaprocessioninwhichthenoddingheadofaclockkingallowedthepassageofaparadeofspear-wieldingbearcubsandaferociouslion!ThemostfamousofearlyautomatawasthecreationofJacquesdeVaucan-son,whoin1738dazzledPariswith“anartificialduckmadeofgildedcopperwhodrinks,eats,quacks,splashesaboutthewater,anddigestshisfoodlikealivingduck.”Thecomplexityofthisduckwasenormous—therewereoverfourhundredmovingpiecesinasinglewing.7.2.2EarlyhistoryofcellularautomataMathematicianStanislawM.Ulamlikedtoinventpatterngamesforthecom-puteratLosAlamos.Givencertainfixedrules,thecomputerwouldprintoutever-changingpatterns.Manypatternsgrewalmostasiftheywerealive.Asimplesquarewouldevolveintoadelicate,coral-likegrowth.Twopatternswould“fight”overterritory,sometimesleadingtomutualannihilation.Hede-veloped3-Dgamestoo,constructingthicketsofcolouredcubesasprescribedbycomputer.Hecalledthepatterns“recursivelydefinedgeometricobjects”.Ulam’sgameswerecellulargames.Eachpatternwascomposedofsquare(ortriangularorhexagonal)cells.Ineffect,thegameswereplayedonlimitless7.2.HistoryofCellularAutomata75chessboards.Allgrowthandchangeofpatternstookplaceindiscretejumps.Frommomenttomoment,thefateofagivencelldependedonlyonthestatesofitsneighbouringcells.Theadvantageofthecellularstructureisthatitallowsamuchsimplerphysics.Withoutthecellularstructure,therewouldbeinfinitelymanypossibleconnectionsbetweencomponents.UlamsuggestedthatJohnvonNeumann“construct”anabstractuniverseforhisanalysisofmachinereproduction.Itwouldbeanimaginaryworldwithself-consistentrules,asinUlam’scomputergames.Itwouldbeaworldcomplexenoughtoembracealltheessentialsofmachineoperation,butoth-erwiseassimpleaspossible.VonNeumannadoptedaninfinitechessboardashisuniverse.Eachsquarecellcouldbeinanyofanumberofstatescor-respondingroughlytomachinecomponents.A“machine”wasapatternofsuchcells.Therulesgoverningtheworldwouldbeasimplifiedphysics.Aproofofmachinereproductionwouldbeeasiertodeviseinsuchanimaginaryworld,asallthenonessentialpointsofengineeringwouldbestrippedaway[1].Ironically,thenamevonNeumannisnowstronglyassociatedwiththeold-fashioned,single-CPUcomputerarchitecture.Hewasalsothemajorpi-oneerinparallelcomputingviahisresearchonarraysofcomputerorcellularautomata.In1944,vonNeumannwasintroducedtoelectroniccomputingviaadescrip-tionoftheENIACbyGoldstine.Shortly,heformedagroupofscientistsheadedbyhimself,toworkonproblemsincomputers,communications,con-trol,time-seriesanalysis,ndthe“communicationsandcontrolaspectsofthenervoussystem”.ThelasttopicwasincludedduetohisgreatinterestintheworkonneuralnetworksofMcCullochandPitts.In1946,vonNeumannpro-ceededtodesigntheEDVAC(ElectronicDiscreteVariableComputer)whichwasthefirstdesignoftheideasonautomatadevelopedbyPost(1936)andTuring(1936),hehadcommencedstudiesonthecomplexityrequiredforadeviceorsystemtobeself-reproductive.Thesestudiesalsoincludedworkontheproblemoforganizingasystemfrombasicallyunreliablep