Umsebenzi we-sigmoid uyingxenye ebalulekile kumanethiwekhi we-neural, ngokuvamile asetshenziswa njengokwenza kusebenze. Kulesi sihloko, sizohlola ngokujulile ukuthi umsebenzi we-sigmoid usebenza kanjani, okuphuma kuwo, nokuthi kungani ubalulekile ekuqeqesheni amanethiwekhi e-neural. Sizobheka ukuthi umsebenzi we-sigmoid unomthelela kanjani ukusebenza kahle ukufunda nokulungisa izisindo zamanethiwekhi e-neural.
Uyini Umsebenzi we-Sigmoid?
Umsebenzi we-sigmoid uwumsebenzi wezibalo othatha inombolo njengokufaka bese ubuyisela inani elisha phakathi kuka-0 no-1. Ifomula yezibalo yomsebenzi we-sigmoid ithi:
σ(x)=11+e−x\sigma(x) = \frac{1}{1 + e^{-x}}
Lo msebenzi uvame ukusetshenziswa njengokwenza kusebenze ezendlalelo ezihlukahlukene zenethiwekhi ye-neural, okunquma ukuthi ingabe i-node kufanele isebenze noma cha futhi ngakho-ke ukuthi kufanele ibe negalelo yini ezibalweni zenethiwekhi.
Kungani Umsebenzi We-Sigmoid Usetshenziswa KumaNethiwekhi We-Neural?
Umphakeli
Isigaba sokuphakela phambili yinqubo lapho idatha igeleza kunethiwekhi ye-neural isuka endaweni yokufaka ibheke endaweni ephumayo, lapho inethiwekhi izama khona ukuqagela. Lezi zibikezelo zibe seziqhathaniswa namanani angempela, futhi iphutha litholwa njengomehluko phakathi kwamanani amabili.
I-Backpropagation
Ngemva kokudlulisela phambili okuphakelayo, ukusabalalisa emuva kwenzeka, lapho "ukufunda" noma "ukushuna" kwenethiwekhi ye-neural kwenzeka. Inani lephutha ligeleza libuyele emuva kunethiwekhi libheke kolunye uhlangothi, lisetshenziswa ngokuhlanganiswa nokuphuma kokunye komsebenzi we-sigmoid ukuze kulungiswe izisindo zawo wonke amanodi eduze kwezendlalelo zenethiwekhi.
I-Derivative Yomsebenzi we-Sigmoid
Okuphuma kokunye komsebenzi we-sigmoid kubalulekile ngesikhathi sokusakazwa emuva. Ibalwa njengomsebenzi we-sigmoid ophindaphindwa ngokukodwa kokukhipha umsebenzi we-sigmoid. Lokhu kuvezwa ngokwezibalo kanje:
σ′(x)=σ(x)⋅(1−σ(x))\sigma'(x) = \sigma(x) \cdot (1 – \sigma(x))
Ukubaluleka kokuphuma kokunye
Okuphuma kokunye komsebenzi we-sigmoid kuvumela ukulungiswa ngokwehla kwe-gradient. Phakathi nokusabalalisa i-backpropagation, okuphuma kokunye komsebenzi wokwenza kusebenze kubalwa izikhathi eziningi, futhi ukuba lula kokuphuma kokunye komsebenzi we-sigmoid kuwenza kusebenze kahle kakhulu kule njongo.
Ungabala Kanjani Okususelwe Komsebenzi We-Sigmoid
Ake sinikeze imininingwane yokubalwa kokuphuma kokunye komsebenzi we-sigmoid sisebenzisa umthetho we-quotient kanye nomthetho we-chain.
I-Quotient Rule
Ngomsebenzi onikezwe ingxenyenazana, umthetho we-quotient usitshela ukuthi singathola okuphuma kokunye komsebenzi ngale ndlela elandelayo:
(uv)′=u′v−uv′v2\left( \frac{u}{v} \kwesokudla)' = \frac{u'v – uv'}{v^2}
Ukusebenzisa lokhu kumsebenzi we-sigmoid, lapho u=1u = 1 e v=1+e−xv = 1 + e^{-x}, sine:
u′=0u' = 0 v′=−e−xv' = -e^{-x}
Ukusetshenziswa kwe-Quotient Rule
Ngokufaka esikhundleni sefomula yomthetho we-quotient, sithola:
σ′(x)=0⋅(1+e−x)−1⋅(−e−x)(1+e−x)2=e−x(1+e−x)2\sigma'(x) = \frac{0 \cdot (1 + e^{-x}) – 1 \cdot (-e^{-x})}{(1 + e^{-x})^2} = \frac{e ^{-x}}{(1 + e^{-x})^2}
Ukwenza lula
Ukwenza kube lula, singabhala kabusha umsebenzi we-sigmoid ngokwemibandela ye σ(x)\sigma(x):
σ(x)=11+e−x\sigma(x) = \frac{1}{1 + e^{-x}}
Bese:
σ′(x)=σ(x)⋅(1−σ(x))\sigma'(x) = \sigma(x) \cdot (1 – \sigma(x))
Lokhu kuqinisekisa ukuthi okuphuma kokunye komsebenzi we-sigmoid kuwumsebenzi we-sigmoid ngokwawo ophindaphindwe ngokukodwa kokususa umsebenzi we-sigmoid.
Izicelo Ezisebenzayo Zomsebenzi we-Sigmoid
Umsebenzi we-sigmoid usetshenziswa kakhulu kumanethiwekhi e-neural ngenxa yendawo yawo yokubeka amanani ebangeni eliphakathi kuka-0 no-1, okusiza ukuchazwa kwemiphumela kanye nokusetshenziswa kwezinkinga kanambambili.
Isibonelo Esisebenzayo
Cabangela inethiwekhi ye-neural esetshenziselwa ukuhlukaniswa kwezigaba kanambambili, lapho okukhiphayo kufanele kube ngu-0 noma 1. Umsebenzi we-sigmoid ulungele lo msebenzi njengoba okukhiphayo kuhlale kunomkhawulo phakathi kuka-0 no-1, okusiza ukuthathwa kwezinqumo kanambambili.
Imibuzo ejwayelekile
1. Uyini umsebenzi we-sigmoid?
Umsebenzi we-sigmoid uwumsebenzi wezibalo osetshenziswa njengokwenza kusebenze kumanethiwekhi e-neural, okwenza imephu noma iyiphi inombolo yangempela ibe nani phakathi kuka-0 no-1.
2. Kungani umsebenzi we-sigmoid usetshenziswa kumanethiwekhi emizwa?
Umsebenzi we-sigmoid usetshenziswa ngenxa yokuthi okukhiphayo kunomkhawulo phakathi kuka-0 no-1, okuwenza ulungele izinkinga zokuhlukanisa kanambambili nokwenza kube lula inqubo yokusabalalisa emuva.
3. Iyini i-backpropagation?
I-Backpropagation iyinqubo yokulungisa izisindo kunethiwekhi ye-neural, lapho iphutha elibalwe kokuphumayo lisakazwa libuyiselwe ngenethiwekhi ukuze kuthuthukiswe izisindo futhi kuthuthukiswe ukuqagela okuzayo.
4. Ingabe okuphuma kokunye komsebenzi we-sigmoid kusetshenziswa kanjani ekusakazweni kwe-backpropagation?
Okuphuma kokunye komsebenzi we-sigmoid kusetshenziselwa ukubala ama-gradient ngesikhathi sokusakazwa kwe-backpropagation, okuvumela ukulungiswa okusebenzayo kwezisindo zenethiwekhi ye-neural.
5. Ithini ifomula yokuphuma kokunye komsebenzi we-sigmoid?
Okuphuma kokunye komsebenzi we-sigmoid kunikezwa:
σ′(x)=σ(x)⋅(1−σ(x))\sigma'(x) = \sigma(x) \cdot (1 – \sigma(x))
Isiphetho
Ukuqonda umsebenzi we-sigmoid nokuphuma kwayo kubalulekile kunoma ubani osebenza ngamanethiwekhi e-neural. Ubulula futhi ukusebenza kahle yomsebenzi we-sigmoid ikwenza kube ukukhetha okudumile njengokwenza kusebenze, ikakhulukazi ezinkingeni zokuhlukanisa kanambambili. Sithemba ukuthi lesi sihloko sinikeze ukuqonda okucacile nokunemininingwane ngokubaluleka komsebenzi we-sigmoid kanye nokusebenza kwawo kumanethiwekhi e-neural.
Hlola Manje! 
