May 2020
Beginner to intermediate
952 pages
24h 11m
Korean
Content preview from 핸즈온 머신러닝(2판): 사이킷런, 케라스, 텐서플로 2를 활용한 머신러닝, 딥러닝 완벽 실무
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136
1
부
머신러닝
>>> recall_score(y_train_5, y_train_pred)
# == 4096 / (4096 + 1325)
0.7555801512636044
이제 ‘
5
-
감지기’가 정확도에서 봤을 때만큼 멋져 보이지는 않네요.
5
로 판별된 이미지 중
72
.
9
%만 정확합니다. 더군다나 전체 숫자
5
에서
75
.
6
%만 감지했습니다.
정밀도와 재현율을
F
1
점수
F
1
score
라고 하는 하나의 숫자로 만들면 편리할 때가 많습니다. 특히
두 분류기를 비교할 때 그렇습니다.
F
1
점수는 정밀도와 재현율의
조화 평균
harmonic
mean
입니다
(식
3
-
3
).
4
식
3-3
F
1
점수
2
2
11
2
1
FPFN
TP
TP
F
+
+
=
+
×
×=
+
=
재현율정밀도
재현율정밀도
재현율정밀도
F
1
점수를 계산하려면
f1
_
score
()
함수를 호출하면 됩니다.
>>> from sklearn.metrics import f1_score
>>> f1_score(y_train_5, y_train_pred)
0.7420962043663375
정밀도와 재현율이 비슷한 분류기에서는
F
1
점수가 높습니다. 하지만 이게 항상 바람직한 것은
아닙니다. 상황에 따라 정밀도가 중요할 수도 있고 재현율이 중요할 수도 있습니다. 예를 들어
어린아이에게 안전한 동영상을 걸러내는 분류기를 훈련시킨다고 가정해보겠습니다. 재현율은 ...
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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.