This lesson is only available in Korean for now.
Dr. Seonggu Sohn's Deep Learning, First Steps

When one line will not do,
you stack layers

/ml lesson 11 ended with try a linear model before you reach for deep learning. These twenty lessons are what comes next.
Start from four points no line can separate, write backpropagation by hand (and check it against numerical differentiation), build attention in six lines, and see why AlphaFold needed that architecture. No PyTorch โ€” you only understand the inside once you have written it.

๐Ÿ Python๐Ÿง  backprop๐Ÿ“‰ vanishing gradients ๐ŸชŸ convolution๐Ÿ‘€ attention๐Ÿงฌ AlphaFold๐Ÿ‡ฌ๐Ÿ‡ง English
Start lesson 1 โ†’

How you'll learn

โœ๏ธBackprop by hand

The chain rule is all it takes. Twenty lines, then checked against numerical differentiation โ€” matching to nine decimals.

๐Ÿ”Start from what fails

We try 220,000 straight lines and confirm that none separates XOR. The reason for stacking layers comes from there.

๐ŸงฌAll the way to biology

Why attention suits proteins, and how AlphaFold reached 92.4 at CASP14.

โš–๏ธNot using it is an answer

The last lesson asks when not to. On tabular data with few samples, logistic regression wins.

Full curriculum

01
์ง์„  ํ•˜๋‚˜๊ฐ€ ๋ชป ํ•˜๋Š” ๊ฒƒ โ€” ๊ทธ๋ž˜์„œ ์ธต์„ ์Œ“๋Š”๋‹ค
/ml 11๊ฐ•์ด ๋ฉˆ์ถ˜ ์ž๋ฆฌ์—์„œ
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02
๋‰ด๋Ÿฐ ํ•˜๋‚˜๋Š” ๋กœ์ง€์Šคํ‹ฑ ํšŒ๊ท€๋‹ค
์ƒˆ๋กœ์šด ๊ฒƒ์ด ์•„๋‹ˆ๋ผ ์ด๋ฏธ ์•„๋Š” ๊ฒƒ
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03
์ธต์„ ์Œ“์œผ๋ฉด โ€” ๊ตฝ์€ ๊ฒฝ๊ณ„๊ฐ€ ์ƒ๊ธด๋‹ค
์€๋‹‰ ์นธ ์ˆ˜์™€ ์ธต ์ˆ˜๊ฐ€ ํ•˜๋Š” ์ผ
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04
์—ญ์ „ํŒŒ โ€” ์—ฐ์‡„๋ฒ•์น™ ํ•˜๋‚˜๊ฐ€ ์ „๋ถ€๋‹ค
์†์œผ๋กœ ์Šค๋ฌด ์ค„์ด๋ฉด ๋๋‚œ๋‹ค
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05
ํ•™์Šต โ€” ์†์‹ค์„ ๊ตด๋Ÿฌ ๋‚ด๋ ค๊ฐ„๋‹ค
ํ•™์Šต๋ฅ  ํ•˜๋‚˜๊ฐ€ ๋˜๊ณ  ์•ˆ ๋˜๊ณ ๋ฅผ ๊ฐ€๋ฅธ๋‹ค
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06
๊ธฐ์šธ๊ธฐ๊ฐ€ ์‚ฌ๋ผ์ง„๋‹ค โ€” ๊นŠ์€ ์‹ ๊ฒฝ๋ง์ด ์˜ค๋ž˜ ์•ˆ ๋˜๋˜ ์ด์œ 
์ดˆ๊ธฐํ™” ยท ReLU ยท ์ž”์ฐจ ์—ฐ๊ฒฐ
โœ“
07
๋ฏธ๋‹ˆ๋ฐฐ์น˜ โ€” ์ „๋ถ€ ๋ณด์ง€ ์•Š๊ณ  ์กฐ๊ธˆ์”ฉ ๋ณธ๋‹ค
์žก์Œ์ด ์˜คํžˆ๋ ค ๋„์›€์ด ๋˜๋Š” ์ž๋ฆฌ
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08
์™ธ์šฐ์ง€ ๋ชปํ•˜๊ฒŒ ๋ง‰๊ธฐ โ€” ์กฐ๊ธฐ์ข…๋ฃŒ ยท ๋“œ๋กญ์•„์›ƒ ยท ๊ฐ์‡ 
๋”ฅ๋Ÿฌ๋‹์—์„œ ๊ณผ์ ํ•ฉ์€ ์˜ˆ์™ธ๊ฐ€ ์•„๋‹ˆ๋ผ ๊ธฐ๋ณธ๊ฐ’์ด๋‹ค
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09
์ •๊ทœํ™” ์ธต โ€” ์ค‘๊ฐ„ ๊ฐ’๋“ค์˜ ๋ˆˆ๊ธˆ์„ ๋งž์ถ˜๋‹ค
๋ฐฐ์น˜ ์ •๊ทœํ™”์™€ ์ธต ์ •๊ทœํ™”
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10
์†์žก์ด๊ฐ€ ๋„ˆ๋ฌด ๋งŽ๋‹ค โ€” ๋ฌด์—‡๋ถ€ํ„ฐ ๋งŒ์ง€๋‚˜
๊ทธ๋ฆฌ๊ณ  '๋Œ๋ฆด ๋•Œ๋งˆ๋‹ค ๊ฒฐ๊ณผ๊ฐ€ ๋‹ค๋ฅธ' ๋ฌธ์ œ
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11
ํ•ฉ์„ฑ๊ณฑ โ€” ๊ฐ™์€ ์ฐฝ์„ ์˜ฎ๊ฒจ ๊ฐ€๋ฉฐ ๋ณธ๋‹ค
์ด๋ฏธ์ง€์™€ ์„œ์—ด, ๊ทธ๋ฆฌ๊ณ  ๊ฐ€์ค‘์น˜๋ฅผ ๋‚˜๋ˆ  ์“ด๋‹ค๋Š” ๋ฐœ์ƒ
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12
์„œ์—ด โ€” ์ฐจ๋ก€๋Œ€๋กœ ์ฝ๊ธฐ์˜ ํ•œ๊ณ„
์ˆœํ™˜ ์‹ ๊ฒฝ๋ง๊ณผ '๋ฉ€๋ฆฌ ์žˆ๋Š” ๊ฒƒ' ๋ฌธ์ œ
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13
์–ดํ…์…˜ โ€” ์–ด๋””๋ฅผ ๋ณผ์ง€ ๋ฐฐ์šด๋‹ค
๊ฑฐ๋ฆฌ์™€ ์ƒ๊ด€์—†์ด, ํ•œ๊บผ๋ฒˆ์—
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14
ํŠธ๋žœ์Šคํฌ๋จธ โ€” ๊ฐ™์€ ๋ฉ์–ด๋ฆฌ๋ฅผ ์Œ“๋Š”๋‹ค
์–ดํ…์…˜ + ์™„์ „์—ฐ๊ฒฐ + ์ž”์ฐจ + ์ธต ์ •๊ทœํ™”
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15
์‚ฌ์ „ํ•™์Šต โ€” ๋‚จ์˜ ๋ชจํ˜•์„ ๊ฐ€์ ธ๋‹ค ์“ฐ๋Š” ์ด์œ 
ํ‘œ๋ณธ์ด ์ ์„ ๋•Œ ๋”ฅ๋Ÿฌ๋‹์„ ์“ธ ์ˆ˜ ์žˆ๊ฒŒ ๋งŒ๋“  ๊ฒƒ
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16
๋‹จ๋ฐฑ์งˆ โ€” ์„œ์—ด์—์„œ ์ ‘ํžŒ ๋ชจ์–‘์œผ๋กœ
AlphaFold ๊ฐ€ CASP14 ์—์„œ ํ•œ ์ผ
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17
์Šฌ๋ผ์ด๋“œ์™€ ์„ธํฌ โ€” ์ด ์‚ฌ์ดํŠธ์˜ ์ž๋ฃŒ์— ๋Œ€ ๋ณด๋ฉด
/til ์˜ ์กฐ๊ฐ 4์–ต 6์ฒœ๋งŒ ๊ฐœ
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18
๋”ฅ๋Ÿฌ๋‹์—์„œ ํŠนํžˆ ์ž˜ ์†๋Š” ๊ฒƒ๋“ค
/ml ์˜ ํ•จ์ •์ด ์—ฌ๊ธฐ์„œ ๋” ์‹ฌํ•ด์ง„๋‹ค
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19
์‹ค์Šต ์ข…ํ•ฉ โ€” ์‹ ๊ฒฝ๋ง ํ•˜๋‚˜๋ฅผ ์ฒ˜์Œ๋ถ€ํ„ฐ ๋๊นŒ์ง€
numpy ๋กœ ์งœ๊ณ , ํ•™์Šต์‹œํ‚ค๊ณ , ์ •์งํ•˜๊ฒŒ ์ฑ„์ ํ•œ๋‹ค
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20
์ •๋ฆฌ โ€” ์–ธ์ œ ์“ฐ๊ณ  ์–ธ์ œ ์•ˆ ์“ฐ๋‚˜
๊นŠ์€ ๊ฒƒ์ด ์–ธ์ œ๋‚˜ ์ด๊ธฐ์ง€๋Š” ์•Š๋Š”๋‹ค
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