5.3.1 Netflix Prize

The Netflix Mubayiro anoshandisa rakavhurika kudanwa kufembera izvo mafirimu vanhu vachange kufanana.

Zvose zvinozivikanwa zvakanyanya kufanira purojekiti ndeyeNetflix Prize. Netflix ikambani yepaIndaneti yakakodzwa, uye muna 2000 yakatanga Cinematch, basa rekurudzira mafirimu kune vatengi. Somuenzaniso, Cinematch inogona kuona kuti iwe wakada Star Wars uye The Empire Strikes Back uye zvinokurudzira kuti utarise Kudzoka kweJedi . Pakutanga, Cinematch yakashanda zvakanaka. Asi, pamusoro pemakore akawanda, yakaramba ichinatsiridza kukwanisa kwayo kufanotaura kuti mafirimu vangave vanofarira. Pakazosvika 2006, zvisinei, kufambira mberi kweCinematch kwakanga kwave kurima. Vatsvakurudzi veNetflix vakaedza zvakanakisisa zvose zvavaigona kufunga, asi, panguva imwe chete, vaifungidzira kuti kune dzimwe pfungwa dzingavabatsira kugadzirisa hurongwa hwavo. Nokudaro, ivo vakauya nezvakanga zviri, nenguva iyo, sarudzo yakasimba: foni yakashama.

Chinokosha pakubudirira kwekupedzisira kweNetflix Prize ndechokuti kudanwa kwakasikwa kwakagadzirwa sei, uye izvi zvakagadziridzwa zvidzidzo zvinokosha zvekuti mafonero akazaruka angashandiswa sei pakutsvakurudza kwevanhu. Netflix haana kungoita chikumbiro chisina kugadziriswa chekufunga, ndizvo izvo vanhu vakawanda vanofunga pavanotanga kufunga nezvekufona. Pane kudaro, Netflix yakaratidza dambudziko rakajeka nekunyoresa nzira yekuongorora: vakakurudzira vanhu kushandisa shanho yemamiriyoni zana emavhidhiyo kuti vafananidze mamiriyoni matatu akachengetwa-maitiro (kukohwa kwevashandi asi kuti Netflix haina kusunungura). Munhu wekutanga kuvaka dhigiriiyo yakafanotaura kuti mamiriyoni matatu akachengetwa 10% akare kupfuura Cinematch ingakunda mamiriyoni emadhora. Izvi zvakajeka uye zviri nyore kushandisa kuongorora nzira-kuenzanisa zviyero zvakatarwa nezvikwanganiso zvakaitwa-zvaireva kuti Mutengo weNetflix wakagadzirirwa nenzira yakadaro kuti mhinduro dzaiva nyore kutarisa kupfuura kuunza; yakashandura chinetso chekuvandudza Cheinchatch kuva dambudziko rakafanira kuti rifone.

Muna Gumiguru ra2006, Netflix yakabudisa dheaset ine mamiriyoni zana emavhidhiyo kuongororwa kubva kune vanenge 500 000 vatengi (tichafunga nezvezvakavanzika zvehuwandu hwekubudiswa kwemashoko muchitsauko 6). Nhamba yeNetflix inogona kugadziriswa sechirwere chikuru chinenge mazana 500 000 vatengi nemavhidhiyo 20,000. Muchikamu ichi, pane zviyero zvemamiriyoni zana pachiyero kubva kune imwe kusvika kune nyeredzi (tafura 5.2). Chinetso chakanga chiri chekushandisa data yakacherechedzwa mumatrix kufanotaura zviyero zvitatu zvakachengetwa.

Vatsvakurudzi nevashambadzi pasi pose vakagamuchirwa kune dambudziko, uye muna 2008 vanhu vanopfuura 30 000 vaiishanda (Thompson 2008) . Pamusoro pemakwikwi, Netflix yakagamuchira zvinodarika makumi mana makumi mana ezviuru zvinogadziriswa zvirongwa zvinopfuura mazana mashanu ezvikwata (Netflix 2009) . Zviri pachena kuti Netflix yakanga isingagoni kuverenga nekunyatsonzwisisa zvose izvi zvinorongwa. Chinhu chose chakamhanya zvakanaka, zvakadaro, nokuti mhinduro dzaiva nyore kuongorora. Netflix inogona kunge iine kombiyuta yakafananidza zviyero zvakagara zvichitongwa nematanho akachengetwa uchishandisa metric (chaiyo yematare yavakashandisa yaiva yakakosha miro yezvinoreva squared error). Uku ndiko kukwanisa uku kukurumidza kutsvaga mhinduro dzakabatsira Netflix kugamuchira mhinduro kubva kune munhu wose, izvo zvakazove zvakakosha nokuti zvakanaka pfungwa dzakabva kune dzimwe nzvimbo dzinoshamisa. Kutaura zvazviri, mhinduro yekukunda yakatumirwa neboka yakatanga nevatsvakurudzi vatatu vakanga vasina ruzivo rwekugadzira mapurogiramu emagetsi epafirimu (Bell, Koren, and Volinsky 2010) .

Chimwe chinhu chakanaka cheNetflix Prize ndechokuti yakaita kuti zvese zvinongororwa zviongororwe zvakanaka. Izvi zvinoreva, apo vanhu vakaisa maitiro avo akafanotaurwa, vaisafanira kuisa zvidzidzo zvavo zvevadzidzi, makore avo, dzinza, zvepabonde, zvepabonde, kana chimwe chinhu pamusoro pavo. Izvo zvakafanotaurwa zviyero zvepurofesa akakurumbira kubva kuStanford zvakarapwa zvakangofanana nezvo kubva kune achiri kuyaruka muimba yake yekuvata. Zvinosuruvarisa, izvi hazvisi zvechokwadi mune tsvakurudzo dzakawanda dzevanhu. Icho chikonzero chekutsvakurudza kwevanhu vakawanda, kuongororwa kunopedza nguva uye zvishoma nezvishoma kuzviona. Nokudaro, pfungwa dzakawanda dzekutsvakurudza hadzina kumboongororwa zvakanyanya, uye kana pfungwa dzichiongororwa, zvakaoma kudzivisa kuongororwa uku kubva kumuvumbi wemafungiro. Vhura mapurogiramu ekushevedza, kune rumwe rutivi, ive nyore uye yakarurama kuongororwa kuitira kuti vawane pfungwa dzingarasikirwa zvimwe.

Somuenzaniso, pane imwe nguva panguva yeNetflix Prize, mumwe munhu ane zita rekuvhara zita rinonzi Simon Funk akatumira pa blog yake sarudzo yakagadziriswa yakabva kune imwechete kukosha kwekugadzirisa, nzira inobva kuargebra yakatarisa yakanga isati yashandiswa kare nevamwe vaitora. Funk's blog post yakange yakafanana neyekuita uye isirdly isina kufanira. Icho chiitiko chebhuku chaive chiri kurondedzera mhinduro yakanaka here kana kuti chaiva kuparadza kwenguva? Kunze kwepurogiramu yakasununguka purojekiti, mhinduro ingadai isati yawana zvakakosha kuongorora. Mushure mezvose, Simon Funk akanga asiri purofesa paMIT; akanga ari nyanzvi yemapurogiramu, panguva iyoyo, akanga achidzokera shure neNew Zealand (Piatetsky 2007) . Kana akange atumira tsamba iyi kune injinjini yeNetflix, zvingadai zvisingamboverengwi.

Nenzira yakanaka, nokuti iyo nzira yekuongorora yakanga yakajeka uye iri nyore kushandisa, zvaakafanotaurira zviyero zvakaongororwa, uye zvakangoerekana zvajeka kuti nzira yake yakanga ine simba zvikuru: akazununguka kusvika kunzvimbo yechina mumukwikwi, chiitiko chikuru chakapiwa chekuti mamwe mauto akanga atove kushanda kwemwedzi pane dambudziko. Pakuguma, zvikamu zvekutaura kwake zvakashandiswa nevose vakakwikwidza (Bell, Koren, and Volinsky 2010) .

Ichokwadi kuti Simon Funk akasarudza kunyora nzvimbo yebhuku achitsanangura nzira yake, panzvimbo yekuedza kuchengeta iyo yakavanzika, zvakare inoratidza kuti vazhinji vanobatanidzwa muNetflix Prize vakanga vasina kungotungamirirwa chete nemamiriyoni emadhora. Asi, vatori vechikamu vazhinji vakaita sekunakidzwa nehutano hwepfungwa uye nharaunda yakagadzirisa dambudziko racho (Thompson 2008) , manzwiro andinotarisira kuti vanotsvakurudza vakawanda vanogona kunzwisisa.

Mutengo weNetflix muenzaniso wekare wefoni yakasununguka. Netflix akabvunza mubvunzo ane chinangwa chaicho (kufanotaura nezvekuona mafirimu) uye akakumbira mhinduro kubva kuvanhu vakawanda. Netflix akakwanisa kuongorora mhinduro idzi dzose nokuti dzaiva nyore kutarisa kupfuura kusika, uye pakupedzisira Netflix yakatora mhinduro yakanakisisa. Zvadaro, ndichakuratidza kuti nzira imwechete inogona kushandiswa sei mubhaibheri uye mutemo, uye pasina mamiriyoni emadhora.