I-Overfitting and Underfitting
I-overfitting yilapho imodeli ibamba ngekhanda idatha yayo yokuqeqeshwa futhi yehluleka ezibonelweni ezintsha; underfitting yilapho kulula kakhulu ukuthwebula iphethini yangempela.
Uhlolojikelele
Hitting the sweet spot between them is the central challenge of machine learning.
I-Deep Dive
Yonke imodeli ilingana nesethi yokuqeqesha enomkhawulo, kodwa umgomo uwukwenza kahle kudatha engabonakali. Imodeli ye-overfit iphatha umsindo nezingqinamba zesethi yokuqeqeshwa njengokungathi isignali yangempela: ingase ithole u-99% kudatha yokuqeqeshwa kodwa igoqe iye ku-70% kusethi yokuhlola. Imodeli ye-underfit iyinkinga ephambene, eqinile kakhulu ukuthi ingathwebula isakhiwo esingaphansi, ngakho-ke yenza kabi kukho kokubili ukuqeqeshwa nedatha yokuhlola. Igebe phakathi kokuqeqeshwa nokusebenza kokuhlolwa kuwuphawu lokutshela. I-underfitting ibonisa njengephutha eliphezulu yonke indawo (ukuchema okuphezulu); ukufakwa ngokweqile kubonisa njengephutha eliphansi lokuqeqesha kodwa iphutha lokuhlola eliphezulu (ukwehluka okuphezulu). Ikhono liwukubona ukuthi iyiphi inkinga onayo, ngoba ukulungiswa kudonsa ngezindlela ezihlukile.
I-Technical Insight
Ukufakwa ngokweqile kanye nokufakwa ngaphansi kweziphetho ezimbili ze-bias-variance tradeoff. Ukuchema kuyiphutha elivela emicabangweni eyenziwe lula kakhulu; ukuhluka kuyiphutha kusukela ekuzweleni kakhulu kusampula yokuqeqeshwa ethile. Imodeli yomugqa omncane inokuchema okuphezulu kanye nokuhluka okuphansi (ama-underfits); imodeli enkulu engavinjelwe inokuchema okuphansi kanye nokuhluka okuphezulu (i-overfits). Iphutha eliphelele elilindelekile licishe libole njengokuchema okuphindeke kabili kanye nokuhluka kanye nomsindo ongenqamuki. Abasebenzi bathola inkinga ngokuqhathanisa ukunemba kwesethi yokuqeqeshwa nesethi yokuqinisekisa ebanjiwe, babheke lapho amajika amabili ehlukana khona.
I-Strategic Impact
Izinqumo ezicacile
Kukusiza ukuthi uhlukanise izimangalo ezicacile zobuchwepheshe kusukela olimini lokumaketha.
Izindleko kanye nesabelomali
Ungabuza imibuzo yokusebenzisa kangcono ngaphambi kokusebenzisa imali noma isikhathi.
Ithimba kanye nokusebenza komsebenzi
Amaqembu anokuqonda okwabiwe enza izinqumo ezingcono zomkhiqizo, inqubomgomo, nokufunda.
Ikusasa Lokucwilisa Ngokugcwele Nokungafaneli
Le mibono ihlala iyisisekelo, kodwa amanethiwekhi amakhulu kakhulu e-neural enze isithombe sakudala sibe nzima. Amamodeli esimanje angaba namapharamitha amaningi kakhulu kunamaphoyinti edatha nokho asasebenza kahle, umbuso omangazayo kwesinye isikhathi obizwa ngokuthi 'ukwehla okukabili' lapho iphutha lokuhlola lehla futhi ngemva kwenani eliphakeme kakhulu. Ucwaningo luya ngokuya lugxila ekutheni kungani amamodeli anepharamitha engeziwe enza jikelele, indima yokwenziwa njalo okuqondile kuzilungiseleli, kanye nokutholwa okuzenzakalelayo okungcono kokushintshwa kokusabalalisa. Lindela ukuxilonga okucebile okumaka ukugcwala ngokweqile emkhiqizweni njengedatha yomhlaba wangempela isuka kudatha yokuqeqeshwa.
Ukuqaliswa Komhlaba Wangempela
Isihlungi sikagaxekile esihlaba umkhosi kuwo wonke ama-imeyili aqukethe igama lomthumeli othile ngenxa yokuthi lowo mthumeli ube nogaxekile kakhulu kudatha yokuqeqeshwa, eshoda ngokuphelele abathumeli abasha (i-overfitting).
Imodeli yenani lendlu esebenzisa izithombe eziyisikwele kuphela futhi indiva indawo, amagumbi okulala, nesimo, ngakho igeja kakhulu ezindaweni ezibizayo (i-underfitting).
Isigaba sesithombe sezokwelapha esifunda ukuthola i-watermark yesithwebuli sesibhedlela esikhundleni sesifo, futhi sehluleke kwezinye izibhedlela (ukufakwa ngokweqile esicini esiyimbumbulu).
Ukuhlela ukulahlekelwa kokuqeqeshwa ngokumelene nokulahlekelwa kokuqinisekisa ngesikhathi sokuqeqeshwa kanye nokuma lapho ukulahlekelwa kokuqinisekisa kuqala ukukhuphuka ngenkathi ukulahlekelwa kokuqeqeshwa kuqhubeka kwehla (ukubamba ukugcwala ngokweqile kusenesikhathi).
Izingozi & Guardrails
Amaqembu ahlukene angasebenzisa igama elifanayo ngokuhlukile, ngakho chaza ububanzi kusenesikhathi.
Amabhentshimakhi angabukeka eqinile kuyilapho ukusebenza komhlaba wangempela kungalingani.
Ukuziba ikhwalithi yedatha nezinhlelo zokuhlaziya kuvame ukudala imiphumela entekenteke.
Ukuqalisa Umhlahlandlela
Qala ngencazelo yolimi olulula yomphumela oyidingayo.
Khetha imethrikhi eyodwa yempumelelo nesimo esisodwa sokuhluleka ngaphambi kokuhlolwa.
Qalisa umshayeli omncane onedatha emele, hhayi isethi yedemo ephucuziwe.
Yenza idokhumenti lapho Ukufaka Okungaphezu Kokubekwe Eceleni Ne-Underfitting kusiza nalapho izindlela ezilula zingcono.
Qhubeka Uhlole
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Umhlahlandlela olandelayo
I-Backpropagation
Imibuzo evame ukubuzwa
What is Overfitting and Underfitting?
I-overfitting yilapho imodeli ibamba ngekhanda idatha yayo yokuqeqeshwa futhi yehluleka ezibonelweni ezintsha; underfitting yilapho kulula kakhulu ukuthwebula iphethini yangempela. Ukushaya indawo emnandi phakathi kwabo kuyinselelo eyinhloko yokufunda ngomshini.
Imodeli ithola u-98% kudatha yayo yokuqeqeshwa kodwa kuphela u-71% kusethi yokuhlola ebanjiwe. Iyiphi inkinga okungenzeka kakhulu?
Igebe elikhulu lapho ukunemba kokuqeqeshwa kuphezulu kodwa ukunemba kokuhlolwa kuphansi kakhulu isiginesha yakudala yokufaka ngokweqile: imodeli ilingana nomsindo kudatha yokuqeqeshwa kunephethini evamile.
Isiphi isimo esichaza kangcono ukungasebenzi kahle?
Imodeli ye-underfit ilula kakhulu ukuthwebula iphethini eyisisekelo, ngakho ayisebenzi kahle yonke indawo, okuhlanganisa nedatha eqeqeshwe ngayo.
Ku-bias-variance tradeoff, ukuhluka okuphezulu kuhlotshaniswa namuphi umphumela?
Ukwehluka okuphezulu kusho ukuthi imodeli ishintsha kakhulu kuye ngedatha yokuqeqeshwa eyibonayo, okuholela ekufakweni ngokweqile. Ukuchema okuphezulu kuwukuphela okuphambene, okwenziwe lula ngokweqile.
Imodeli ezenzakalelayo yemalimboleko isebenzisa kuphela iminyaka yomfakisicelo futhi ayizibi imali engenayo, isikweletu, nomlando wesikweletu. Isebenza kabi kukho kokubili ukuqeqeshwa nedatha entsha. Yini okufanele uyenze?
Ukusebenza kabi yonke indawo kubonisa ukungafaneleki. Ukulungiswa kuwukwandisa umthamo wemodeli, ngokuvamile ngokungeza izici ezifundisayo, ukuze imele ubudlelwano bangempela.
Kungani ukuqinisekiswa okubanjiwe noma isethi yokuhlolwa kubalulekile ukuze kutholwe ukugcwala ngokweqile?
Ukufakwa ngokweqile akubonakali uma ubheka kuphela ukunemba kokuqeqeshwa. Ukuhlola kudatha engabonakali kuveza igebe phakathi kokubamba ngekhanda nokwenza okuvamile kwangempela.