BBC HorizonThe Age of Big DataWord文件下载.docx

BBC HorizonThe Age of Big DataWord文件下载.docx

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6am,LosAngeles.ThestartofshiftintheFoothilldivision.

OfficerSteveNunes,a12-year-veteranoftheLAPD,andhispartnerDannyFraserheadouttopatrol.

Rightnow,we'

renorthofLosAngeles,downtownLosAngeles,intheSanFernandoValleyarea.

TheirbeatisoneofLA'

stoughestneighbourhoods.

There'

salotofBFMVs,burglaryfrommotorvehicles.

salotofrobberies,there'

salotofgangandnarcoticactivityoverhere.

salotofpeoplesellingdrugs.

Thegangthat'

sinthisareaarecalledtheProjectBoys.

They'

reaHispanicgang.

Despitetheirexperienceandintimateknowledgeoftheneighbourhood,today,theirpatrolisbeingcontrolledbyacomputeralgorithm.

Youknow,Iwasn'

treallytoohappyaboutit,youknow,speciallyasapoliceofficeryouknow,wekindofgooffofwhatweknowfromourtraining.

Weweren'

ttoohappyaboutacomputertellinguswhereweneedtodoourpoliceworkandwhatareaweneedtodrivearound.

SteveandDannyarepartofaground-breakingtrial.

Anequationisbeingusedtopredictwherecrimewilloccurontheirwatch.

Isawsomepeoplehangingoutbythelaundry,likethelittlelaundry.

Icanseethecorner.

Allright,let'

sstop.

Ifitspredictionsarecorrect,thesystemwillberolledoutacrossallLA.

-Hey,stop,yeah,stop.-Stop.

Putyourhandsonyourhead.

AndthecomputeralgorithmwillbecomearoutinepartofSteve'

sworkinglife.

Spreadyourfeet,faceforward.

-Haveanythingonyou?

-Stopmoving.

YouaProjectBoytooorno?

TheambitiontopredictcrimewasbornoutofaremarkablecollaborationbetweentheLAPD...

andtheUniversityofCalifornia.

JeffBrantinghammightseemanunlikelycrimefighter.

Aprofessorofanthropology,heisanexpertonremotehunter-gatherertribesinChina,buthe'

sconvinced

thatfromremoteChinatoganglandLA,allhumanbehaviourisfarmorepredictable

thanyoumightliketobelieve.

Weallliketothinkthatweareincontrolofeverything,butinfactallofourbehaviourisveryregular,verypatternedinwaysthatisoftenfrighteningtous.

Offendersarenodifferent.

Theydoexactlythesamethingsoverandoverandoveragain,andtheircriminaloffendingpatternsemergerightoutofthatregularityoftheirbehaviour.

JeffbelievedhecouldfindrepeatingpatternsofcriminalbehaviourintheLAPD'

svastdataset-

13millioncrimesrecordedover80years.

TheLAPDhavedrovesanddrovesofdataaboutwhereandwhencrimeshavebeenoccurring.

Itrepresentsatreasuretroveofpotentialinformationforunderstandingthenatureofcrime.

TheLAPDalreadyusetheircrimedatatoidentifyhotspotsofcrime,butthatonlytellsthemwherecrimehasalreadystruck.

We'

vegottenverygoodatlookingatdotsonamap,andwhere,wherecrimehasoccurredandtheproblemwiththatisthat,sometimes,you'

remakinganassumptionthattodayisthesameasyesterday.

JeffBrantinghamplannedtodosomethingmoreradicalandmoreusefulpredictthefuture.

Hebelievedhecouldusepatternsinthecrimedatatopredictwhereandwhencrimewaslikelytooccur.

velongusedthepatternsinnaturetomakepredictions.

Fromthesettingsun,

welearnedwhentoexpectthenewday.

Thephasesofthemoonallowedustoforecasttheebbandflowofthetides.

Andfromobservingthepatternsofthestars,wemasteredtheartofnavigation.

ButJeffBrantinghamwantedtodosomethingfarmoreambitious.

Hewantedtoteaseoutpatternsintheapparentchaosofhumanbehaviour,touncoverthemintheLAPD'

svastdatasetof13millionpastcrimes.

Youcanhavegutfeelingsaboutthecrime,butultimately,youneedtothinkaboutworkinginamathematicalframework.

Becausemathematicsgivesyoutheabilitytounderstandexactlywhythingsarehappeningwithinthedatainawaythatgutfeelingsdonot.

Jeffneededanexpertinpatterndetection.

Heturnedtohiscolleague,UCLAmathematicianGeorgeMohler.

Asmathematicians,we'

reinterestedinunderstandingwhat'

saroundyouso,youknow,howdowavespropagateifyouthrowapebbleintothewater?

Thedistributionoftreesinaforest.

Somathematicalmodels

canhelpyouunderstandthosetypesofthings.

Georgecouldusemathematicaltoolstoseewhatwashiddeninthecrimedata.

Andtherewerehintsofapatterninit.

Whatyouseeisthatafteracrimeoccurs,there'

sanelevatedriskandthatrisktravelstoneighbouringregions.

Sowhatwewantedtodoisdevelopamodeltotakethatintoaccountsopolicecouldmaybeusethatinformationtopreventthosecrimesfromoccurring.

Hestartedwithamathematicalmodelthatwasalreadybeingused,righthereonthewestcoastofAmerica.

SouthernCaliforniaisearthquakecountry.

SittingontheSanAndreasFault,there'

sanaverageof10,000earthquakesandafter-shockseveryyear.

Thebiggestfor100yearswastheLomaPrietaearthquakeof1989.

Itsepicentrewashere,justoutsideSantaCruz,California.

Thereisquitesimplynomathematicalmodelthatcanpredictanearthquakelikethisone.

Butaftertheearthquakecometheafter-shocksandthat'

sadifferentmatter.

Sowe'

reseveralhundredmetresfromtheepicentre.

Nearbywasoneoftheafter-shocksoftheoriginalLomaPrietaearthquake.

Afteralargeearthquakeoccurs,thereisaprobabilitythatanotherearthquakewillfollownearbyinspaceandtime.

Georgediscoveredseismologistshadfoundapatterntoearthquakeafter-shocksanddevelopedanalgorithmtopredicttheseafter-shockclusters.

Thesetypesofclusteringpatternsarealsoseenincrimedata.

So,afteracrimeoccurs,youwillseeanincreasedlikelihoodoffutureeventsnearbyinspaceandtime.

Youcanthinkofthemasafter-shocksofcrime.

GeorgeandJefftooktheequationforpredictingearthquakeafter-shocksandbegantoadaptittopredictcrime.

Sothemodelisbrokenintoseveralparts,sotheoverallrateofcrime,whichwe'

llcallLamda,modelstherateofeventsinspaceandtime.

WeusetheGreekletterMyutorepresentthebackgroundamountofcrimethat'

sgoingon.

ThesecondcomponenttoLamdaisG.

Gmodelsthedistributionofcrimesfollowinganinitialevent.

Thiswholetermoveralldescribeswhatwecallself-excitation,thatacrimethatoccurstodayactuallyself-excitesthepossibilityoffuturecrimes.

SoLamdaequalsMyuplusG,isthatright?

Well,sortof,soLamdaequalsMyuplusGpositionedatallthepasteventsinyourdataset.

GeorgeandJefftooktheiralgorithmbacktothestreetsofLA.

Whentheypluggedtheoldcrimedataintotheequation,itgeneratedpredictionsthatfittedwhathadhappenedinthepast.

Butcoulditalsopredictthefuture?

Theybegantoproducedailycrimeforecasts,identifyinghotspotswherecrimewaslikelytostrikeinthefuture.

-Adam11,Nunes.-Sir

-Thern.-Sir.

-Adam23,Fowler.-Sir.

-Wallier.-Sir.

Let'

sgotothemissionmapsifyouwould,please.

Today,theLAPDisputtingthesepredictionstothetest.

ThecopsinFoothillareassignedboxesofjust500squarefeetwherethealgorithmpredictscrimeismostlikelytooccurintheir12-hourwatch.

Right,predictivemissionfortodayis,we'

vegot15boxesheretoaddress,inAdam11'

sarea,12260FoothillBoulevard.

reinstructedtohittheirboxesasoftenastheycan.

OsborneandFoothillBoulevard.

Soyou'

vegotyourmissionfortheday?

Solet'

sgooutthere,havefunandbesafe.

Yeah,thereisahomicideblinkingupthere.

ThetrialismonitoredattheRealTimeCrimeCentreindowntownLA.

Whatwe'

relookingathereistheforecastthatwasproducedbythePredPolsoftware.

Soifyouseeonthecentreofthismap,we'

vegotthreenearlycontiguousforecastboxesaroundthisarea,andthenanadjacentone.

Sothisisgoodinformationfortheofficers.

Theycangooutthere,workupanddownthatstreet,Sheldon,andsomeofthosesidestreets,andlookforcriminalactivityorevidencethatcriminalactivitymightbeafoot.

OK,Roger,we'

lltakeit.

SteveandDannyhavegotthewordtogo.

Themodelhaspredictedcarcrimeinaboxontheirbeat.

Youknowwhatthecallisright?

Thefiveincidentsweremacerated.

Lookslikeit'

sakid.

Yeah,it'

sthesameaddressasthatkidthatwehadyesterday.

Suspectsfour,male...Whentheyreachtheirassignedhotspot,theyfindacold-platedcar.

Thelicenceplatesdon'

tmatchthevehicle.

regettingwhattheyneed,huh?

Whentheycallthenumberin,itturnsoutthecar'

sbeenstolen.

Itwasanareawherethere'

salotofGTAs,whichis"

Grandtheftauto"

peoplewerestealingcars.

Rightoutofrollcall,rightwhenwegotdownoneoftheboxestheywentinto,oneoftheareastheystartedpatrolling,rightawaytheyranacaranditcamebackstolen.

InFoothill,theyfoundusi