January 2017
Beginner to intermediate
312 pages
7h 3m
Korean
Content preview from 밑바닥부터 시작하는 딥러닝
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76
밑바닥부터 시작하는 딥러닝
3.2.7
ReLU
함수
지금까지 활성화 함수로서 계단 함수와 시그모이드 함수를 소개했습니다. 시그모이드 함수는
신경망 분야에서 오래전부터 이용해왔으나, 최근에는
ReLU
Rectified
Linear
Unit
, 렐루
함수를 주로 이
용합니다.
ReLU
는 입력이
0
을 넘으면 그 입력을 그대로 출력하고,
0
이하이면
0
을 출력하는 함수입니다
(그림
3
-
9
).
그림
3-9
ReLU
함수의 그래프
*
ReLU
함수를 수식으로 나타내면 [식
3
.
7
]처럼 쓸 수 있습니다.
hx
xx
x
()
(0)
0( 0)
2
#
=
(
[식 3.7 ]
그래프와 수식에서 보듯
ReLU
는 간단한 함수입니다. 그래서 다음과 같이 쉽게 구현해 쓸 수
있습니다.
*
옮긴이_
ReLU
에서
Rectified
란 ‘정류된’이란 뜻입니다. 정류 (整流)는 전기회로 쪽 용어로, 예를 들어 반파정류회로 (
half
-
wave
rectification
circuit
)는 +/-가 반복되는 교류에서 - 흐름을 차단하는 회로입니다. [그림
3
-
9
]와 비교하면
x
가
0
이하일 때를 차단하여 아
무 값도 출력하지 않는 (
0
을 출력하는) 것이죠. 그래서
ReLU
함수를 ‘정류된 선형 함수’ 정도로 옮길 수 있겠으나, 간단한 개념을 어려운 용
어로 바꾼다는 느낌이라 그만두었습니다.
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.