Prática de Shadowing: P2 什么是机器学习【2024公认最好的 | 吴恩达机器学习 | 教程 | Machine Learning Specialization(超爽中英!)】 - Aprenda a falar inglês com vídeo

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So what is machine learning?
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In this video you learn a definition of what it is
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and also get a sense of when you might want to apply it.
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Let's take a look together.
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Here's the definition of what is machine learning that is attributed to Arthur Samuel.
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He defined machine learning as the field of study that gives computers the ability to learn without being explicitly programmed.
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Salva's claim to fame was that back in the 1950s he wrote a checkers playing program.
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And the amazing thing about this program was that Arthur Samuel himself wasn't a very good checkers player.
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What he did was he had programmed a computer to play maybe tens of thousands of games against himself.
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And by watching what sorts of board positions tended to lead to wins and what positions tended to lead to losses,
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the checkers playing program learned over time what are good or bad board positions.
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By trying to get to good and avoid bad positions, his program learned to get better and better at playing checkers.
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Because the computer had the patience to play tens of thousands of games against itself,
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it was able to get so much checkers playing experience that eventually it became a better checkers player than author Samuel himself.
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Now, throughout these videos, besides me trying to talk about stuff,
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I'll occasionally ask you a question to help make sure you understand the content here's one about what happens
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if the computer had played far fewer games please take a look
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and pick whichever you think is a better answer thanks for looking at the quiz and so
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if you had selected this answer would have made it worse
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then you got it right in general the more opportunities you give a learning algorithm to learn, the better it will perform.
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If you didn't select the correct answer the first time, that's totally okay too.
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The point of these quiz questions isn't to see if you can get them all correct on the first try.
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These questions are here just to help you practice the concepts you're learning.
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Author Samuel's definition was a rather informal one, but in the next two videos, we'll dive deeper together into what are the major types types of machine learning algorithms.
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In this class, you learn about many different learning algorithms.
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The two main types of machine learning are supervised learning and unsupervised learning.
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We'll define what these terms mean more in the next couple videos.
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Of these two, supervised learning is the type of machine learning that is used most in many real -world applications,
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and that has seen the most rapid advancement and innovation.
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In this specialization, which has three causes in total, the first and second causes will focus on supervised learning,
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and the third will focus on unsupervised learning.
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You might have also heard of reinforcement learning.
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This is another type of machine learning algorithm that I'll talk about briefly,
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but by far the two most used types of learning algorithms today are supervised learning and unsupervised learning.
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That's why we'll spend most of this class talking about them.
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The other thing we're going to spend a lot of time on in this specialization is practical advice for applying learning algorithms.
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This is something I feel pretty strongly about.
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Teaching about learning algorithms is like giving someone a set of tools
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and equally important
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or even more importance than making sure you have great tools is making sure you know how to apply them
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because you know what good is it
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if someone were to give you a state -of -the -art hammer
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or a state -of -the -art hand drill
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and say good luck now you have all the tools you
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need to build a three -story house It doesn't really work like that.
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And so too in machine learning, making sure you have the tools is really important.
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And so it's making sure that you know how to apply the tools of machine learning effectively.
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So that's what you get in this class, the tools as well as the skills in applying them effectively.
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I regularly visit with friends and teams in some of the top tech companies.
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And even today, I see experienced machine learning teams apply machine learning algorithms to some problems.
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And sometimes they've been going at it for six months without much success.
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And when I look at what they're doing, I sometimes feel like I could have told them six months ago that the current approach won't work.
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And there's a different way of using these tools that will give them a much better chance of success.
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So in this class, one of the relatively unique things you learn is you learn
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a lot about the best practices for how to actually develop a practical, valuable machine learning system.
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This way, you're less likely to end up in one of those teams
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that end up losing six months going in the wrong direction.
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In this class, you gain a sense of how the most skilled machine learning engineers build systems,
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and I hope you finish this class as one of those very rare people in today's world
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that know how to design and build serious machine learning systems.
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So that's machine learning.
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In the next video, let's look more deeply at what is supervised learning and also what is unsupervised learning.
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In addition, you learn when you might want to use each of them, supervised and unsupervised learning.
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I'll see you in the next video.

Vocabulário e dicas de fala para esta lição

Este vídeo tem 64 frases e 927 palavras para praticar shadowing. A fala dura 5:36. O falante fala em ritmo natural, cerca de 166 palavras por minuto, próximo de uma conversa do dia a dia. 88% das palavras estão entre as 3.000 mais comuns do inglês; vale a pena estudar o restante antes de começar.

Vocabulário principal deste vídeo

15 palavras do vídeo que vale a pena aprender, com pronúncia e significado:

PalavraPronúnciaSignificado
algorithm substantivo/ˈælɡəɹɪðm̩/algoritmo
practical adjetivo/ˈpɹæk.tɪ.kəl/prático
select verbo/sɪˈlɛkt/escolher, selecionar
skill substantivo/skɪl/habilidade, talento
define verbo/dɪˈfaɪn/definir
quiz substantivo/kwɪz/quiz
deeply advérbio/ˈdi(ː)pli/profundamente
equally advérbio/ˈiːkwəli/igualmente
occasionally advérbio/əˈkeɪʒənəli/ocasionalmente
rapid adjetivo/ˈɹæp.ɪd/rápido
fame substantivo/feɪm/fama
innovation substantivo/ˌɪn.əˈveɪ.ʃən/inovação
fewer/ˈfjuː.ɚ/menos
patience substantivo/ˈpeɪ̯.ʃəns/paciência
hammer substantivo/ˈhæmɚ/martelo

Phrasal verbs que você vai ouvir

PalavraSignificado
end up verboterminar, acabar

Pronúncia para ficar de olho

O falante usa 16 contrações e formas reduzidas, como I'll, we'll, you're. Diga-as na forma curta, do jeito que você ouve.

  • Os sons de “sh” e “zh”: occasionally /əˈkeɪʒənəli/, innovation /ˌɪn.əˈveɪ.ʃən/, patience /ˈpeɪ̯.ʃəns/, specialization [ˌspɛʃəlaɪ̯ˈzeɪ̯ʃn̩]
  • Palavras longas — acerte a sílaba tônica: occasionally /əˈkeɪʒənəli/, innovation /ˌɪn.əˈveɪ.ʃən/, specialization [ˌspɛʃəlaɪ̯ˈzeɪ̯ʃn̩], reinforcement /ˌɹiːɪnˈfɔːsmənt/

Como praticar com este vídeo

  1. Ouça o vídeo inteiro uma vez sem falar e anote as palavras que você não conhece.
  2. Comece na velocidade 0,75×, faça shadowing frase por frase e volte à velocidade normal quando ficar fácil.
  3. Grave a sua voz e compare com o original, prestando atenção a palavras como algorithm, practical, select.

O que é a Técnica de Shadowing?

Shadowing é uma técnica de aprendizado de idiomas com base científica, originalmente desenvolvida para o treinamento de intérpretes profissionais. O método é simples, mas poderoso: você ouve áudio em inglês nativo e repete imediatamente em voz alta — como uma sombra seguindo o falante com 1-2 segundos de atraso. Pesquisas mostram melhora significativa na precisão da pronúncia, entonação, ritmo, sons conectados, compreensão auditiva e fluência na fala.

Técnica de shadowing: leia o guia completo passo a passo →