Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

수학을 1도 몰라도 알 수 있는 구글 번역과 알파고의 비밀

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Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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*주의�:��발표자는�기계학습과�수학을�1도�모릅니다.��전적으로�디자이너의�관점에서�쓰였으니�프로그래머�분들의�

양해를�미리�구합니다

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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사람은�복잡한�문제를�어떻게�그렇게�빠르고�효율적으로�처리할�수�있는가?�

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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인공신경망�:��사람의�신경망을�본딴�방법론�

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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기본�요소�:��뉴런,�시냅스�

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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�신경�전달�물질의�양에�따라서�다른�신호가�전달

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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�신경�전달�물질의�양에�따라서�다른�신호가�전달

(1958)

Frank Rosenblatt

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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단층�퍼셉트론�모델

XXX

input�layer output�layer

Y0

1

2

Sw0

w1

w2

활성화�함수�(Activation�function)

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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단층�퍼셉트론�모델

XXX

input�layer output�layer

Y0

1

2

Sw0

w1

w2

활성화�함수�(Activation�function)

But…

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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XOR�ProblemOR�Problem

O.OO. II . II .O

O

I

XOR�Problem

O.OO. II . II .O

O

IO

둘�중�하나만�참이어도�참 둘�중�하나라도�다르면�거짓

I

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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x

y

XX

x

y

X

X

linear model

???

다층�퍼셉트론�모델

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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x

y

X

X

Non-linear model

_아무리�선을�잘�그어도�구분할�수가�없다.�

_비�선형�분류�방법의�필요성�대두�

_은닉층이�포함된�다층�퍼셉트론�모델의�등장

다층�퍼셉트론�모델

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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다층�퍼셉트론�모델input�layer output�layer

w

hidden�layer

w SS

S

ΣΣ

Σ

back�propagation

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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1.은닉층은�몇�개,�몇�층으로�구성되어야�하는가?�_답은�없다.�계속�해보는�수밖에�

_층이�많아지고�노드가�많아져도�성능이�증가하는�것이�아니다.(딥러닝의�시발점)�

2.초기값�가중치는�어떻게�정하는가?�_초기값에�따라서�결과가�달라질�수�있음.(지역�최적화�문제)�

3.인과관계가�불분명�하다.�_결과가�어떻게�나오는지�중간�과정이�명확하지�않다.

다층�퍼셉트론�모델의�문제

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

What is Support vector machine?

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Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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두개의�클래스를�가진�점들을�어떻게�‘잘’�구분할�수�있을까?

x

y

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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점들은�무수히�많은�선들로�분류할�수�있다.

x

y

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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그렇다면�가장�좋은�선은�무엇일까?

x

y

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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두�클래스간�여유공간이�가장�많은�면(Maximum�margin)

x

y

support�vector

margin

hyperplane

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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1차원�문제라면…?

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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1차원�문제라면…?

구분�불가

(?)

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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1차원�문제라면…?

???

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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어떻게�하면�좋을까?

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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차원을�늘려본다면…?

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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보이지�않던�경계면이�보일�수도�있다!

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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보이지�않던�경계면�:�line,�plane이�아닌�hyperplane(초평면)

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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kernal�trick

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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분류상에서�최적의�분류선을�보장

ANN�vs�SVM

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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1.커널�선택의�어려움�_데이터의�속성에�따라�적합한�커널이�달라짐�

2.차원의�저주�_차원이�높은�데이터의�최적�분류�평면을�찾기�위한�시간이�매우�오래�걸림

SVM의�문제

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

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1.양질의�데이터�2.전처리�

->좋은�데이터를�많이�넣어서�학습시키자!�-�구글이�잘할수�밖에�없는�이유

Deep�learning

Designer programmer meet Seminar 2016/11/19

_Lee ji-yun

Thank you for your listening!

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