인공신경망 (Artificial Neural Network)

 우리네 인간의 학습 능력은 어떤 메커니즘으로 작동하는가? 비밀은 신경망에 있다.

1. 인간 신경망

 대뇌피질의 신경세포는 다음과 같이 수상돌기(dendrite)를 통해 다른 여러 신경세포로부터 입력 신호를 받아, 세포체(cell body)에서 정보 연산을 처리하고 축색(axon)을 통해 처리된 정보를 다른 신경세포로 전달한다. 이러한 신경세포는 시냅스라는 가중 연결자(weighted connectior)로 여러 층의 신경망을 구성한다.


 세포체에서의 연산은 입력 신호들의 합을 구하고 그것이 일정한 임계치가 되면 축색이 활성화되어 스파이크를 일으켜 다른 신경세포로 전기 신호를 전달한다. 이러한 특성을 모방하여 만든 것이 인공 신경망(artificial neural network)이다.

2. 인공 신경망

 하나의 인공 신경세포(perceptron)는 다음과 같이 n개의 입력 x1, x2, ..., xn에 대해 연결 강도 w1, w2, ..., wn에 따른 가중치를 곱하여 모든 값의 합(summation)을 구한다. 수식으로 표현하면, u = Σwixi


 이 가중치의 합은 다시 활성화 함수(activation function)를 통과해서 다음 신경세포로 전달될 출력을 결정한다. 위 축색에 활성화 함수는 0 또는 1로 출력하는 계단식 함수가 표현되어 있지만 이부분을 사용자 정의 함수로 원하는 특성을 가진 인공신경망 모델을 구현할 수 있다. 아래는 공돌이식 다이어그램.


 이렇게 활성화 함수를 정의하여 하나의 인공 신경세포에 대한 모델이 정립되면, 다음엔 이들의 연결구조를 고려한다. 우리는 다층 퍼셉트론을 볼 것이기 때문에 입력층과 출력층 사이에 1개 이상의 은닉층을 가지는 구조의 다층 신경망 구조를 한번 보자.


 이러한 신경망 구조에서의 학습은 시냅스의 연결 강도(weight)를 변화시키는 것인데 가장 기본적인 방법은 헤브의 학습 규칙으로 연결된 두 신경세포가 동시에 활성화되면 가중치를 증가시키는 방법이다. 해당 블로그에서 우리는 보다 진화한 오류역전파 알고리즘을 중점적으로 파기로 한다.

3. 다층 퍼셉트론

 다층 퍼셉트론은 인공 신경세포 퍼셉트론을 이용한 XOR문제를 먼저 이해해야하는데, 퍼셉트론 패턴 분류의 약점으로 선형 판별함수 때문에 XOR과 같은 출력을 내도록 경계선(hyperplane)을 만드는게 불가능하여 비선형 경계선을 만들기 위해 은닉층을 추가한게 다층 퍼셉트론이다.

 이제 곧 퇴근을 위하여, 구체적인 다층 퍼셉트론과 하마의 mini SGD기반 MLP 알고리즘으로 분류하는 기법은 다음 글에서 만나기로 하며 마친다.

43 comments:

  1. Our Artificial Intelligence course syllabus includes all the latest algorithms including ANN, MLP, CNN, RNN, LSTM, Autoencoders and many more and this course is considered to be best artificial intelligence course in this region. machine learning course

    ReplyDelete
  2. Top quality article with very informative information and found very knowledgeable thanks for sharing waiting for next blog.
    Data Analytics Course Online

    ReplyDelete
  3. Excellent blog with very impressive writing and unique content, information shared was very valuable and useful thanks for sharing.
    Data Science Course in Hyderabad

    ReplyDelete
  4. PMP Training19/10/20 23:00

    From the tons of comments on your posts, I guess I'm not the only one who has all the free time here. Keep up the good work. I was planning to write something like this on my website and you gave me an idea. PMP Training in Hyderabad

    ReplyDelete
  5. Hi, This is a nice article you shared great information I have read it thanks for giving such a wonderful Blog for the reader. Water Softener System

    ReplyDelete
  6. I discovered your this post while hunting down some related data on website search...Its a decent post..keep posting and upgrade the data 토토사이트

    ReplyDelete
  7. Great article, a debt of gratitude is in order for assembling this! This is clearly one awesome post 토토사이트

    ReplyDelete
  8. 정말 많은 정보와 누군가에 대한 정보가있는이 사이트를 방문한 후 놀라운 경험. 또한 http://www.cosjj.com/에서 고품질의 코스프레 의상을 구입할 수 있습니다. 우르두어로 된 최신 업데이트에 대한 뉴스 업데이트가 가장 좋습니다. 그냥 즐기세요. 토토사이트

    ReplyDelete
  9. I am propelled by the information that you have on this blog. It demonstrates how well you grasp this subject 메이저사이트

    ReplyDelete
  10. "I have been looking for articles on these topics for a long time. 먹튀검증 I don't know how grateful you are for posting on this topic. 토토커뮤니티사이트Thank you for the numerous articles on this site, I will subscribe to those links in my bookmarks and visit them often. Have a nice day
    토토커뮤니티"

    ReplyDelete
  11. I've been troubled for several days with this topic. 먹튀검증, But by chance looking at your post solved my problem! I will leave my blog, so when would you like to visit it?

    ReplyDelete
  12. 토토마틴에서는 검증 된 토토사이트만 선별하여 방문자들에게 제공합니다. 안전놀이터,메이저사이트,메이저놀이터는 토토마틴에서 검증 후 이용하시는 것이 ...

    ReplyDelete
  13. I’ve been absent for a while, but now I remember why I used to love this website. Thanks, I will try and check back more often. How frequently you update your site?
    egaon casino

    ReplyDelete
  14. Hi there mates, how is all, and what you would like to say concerning this
    article, in my view its truly awesome in favor of me.

    Click here to chceck my blog :: 휴게텔
    (jk)

    ReplyDelete
  15. Wow it is really wonderful and awesome thus it is very much useful for me to understand many concepts and helped me a lot. it is really explainable very well and i got more information from your blog.
    DevOps Training in Hyderabad
    DevOps Course in Hyderabad

    ReplyDelete
  16. I wanted to thank you for this excellent read!! I definitely loved every little bit of it. I have you bookmarked your site to check out the new stuff you post 무료야설 .

    ReplyDelete
  17. I can see that you are an expert at your field! I am launching a website soon, and your information will be very useful for me.. Thanks for all your help and wishing you all the success in your business 휴게텔

    ReplyDelete
  18. Your blog is so amazing 출장안마. Information is very useful for everyone. such a amazing post please keep posting.

    ReplyDelete
  19. I assumed it is usually a preview to post in case others appeared to be having problems getting acquainted with nonetheless We're a little bit hesitant merely i'm permitted to decide to put companies plus covers for listed here 타이마사지

    ReplyDelete
  20. Hello, I'm happy to see some great articles on your site. Would you like to come to my site later? My site also has posts, comments and communities similar to yours. Please visit and take a look 토토사이트


    ReplyDelete
  21. I'm so happy to finally find a post with what I want. 메이저토토사이트 You have inspired me a lot. If you are satisfied, please visit my website and leave your feedback.


    ReplyDelete
  22. When I read your article on this topic, the first thought seems profound and difficult. There is also a bulletin board for discussion of articles and photos similar to this topic on my site, but I would like to visit once when I have time to discuss this topic. 안전토토사이트


    ReplyDelete
  23. I was impressed by your writing. Your writing is impressive. I want to write like you.안전놀이터 I hope you can read my post and let me know what to modify. My writing is in I would like you to visit my blog.


    ReplyDelete
  24. Oh, the data you've shared in this incredible article is just magnificent. I am definitely going to make more use of this data in my future projects. You must continue sharing more data like this with us. 먹튀검증업체


    ReplyDelete
  25. Youre so right. Im there with you. Your weblog is definitely worth a read if anyone comes throughout it. Im lucky I did because now Ive received a whole new view of this. 메이저사이트추천


    ReplyDelete
  26. You uploaded a fantastic write-up. I was extremely touched after I saw your writing, and also I actually suched as the tale of what I was seeking due to the fact that it consisted of whatever. I'm so interested concerning exactly how you considered this info and also exactly how you discovered it. Take a look at my writing and also let me recognize. click the up coming document

    ReplyDelete
  27. Hi there, I simply hopped over in your website by way of StumbleUpon. Now not one thing I’d typically learn, but I favored your emotions none the less. Thank you for making something worth reading. 메이저사이트순위


    ReplyDelete
  28. Excellent information on your blog, thank you for taking the time to share with us. Amazing insight you have on this, it's nice to find a website that details so much information about different artists 토토

    ReplyDelete
  29. I accidentally searched and visited your site. I still saw several posts during my visit, but the text was neat and readable. I will quote this post and post it on my blog. Would you like to visit my blog later? 토토사이트순위


    ReplyDelete
  30. Hello, I am one of the most impressed people in your article. 안전놀이터추천 I'm very curious about how you write such a good article. Are you an expert on this subject? I think so. Thank you again for allowing me to read these posts, and have a nice day today. Thank you.


    ReplyDelete
  31. This is the perfect post.메이저토토사이트 It helped me a lot. If you have time, I hope you come to my site and share your opinions. Have a nice day.


    ReplyDelete
  32. Thank you for this wonderful post! It has long been extremely helpful. 메이저사이트I wish that you will carry on posting your knowledge with us.


    ReplyDelete
  33. Your skill is great. I am so grateful that I am able to do a lot of work thanks to your technology.메이저사이트 I hope you keep improving this technology.
    2222.mystrikingly.com/blog/tower-of-babel-cc4d66bf-502f-46a0-a6a4-cefe18cf8e53

    ReplyDelete
  34. I'm impressed, I must say. Actually rarely can i encounter a blog that's both educative and entertaining, and without a doubt, you could have hit the nail about the head. Your idea is outstanding; the thing is something that too few individuals are speaking intelligently about. We are delighted that we came across this around my try to find some thing with this.<a href="https://telegra.ph/PAYDAY-09-09>메이저사이트</a>


    ReplyDelete
  35. 먹튀검증15/11/21 01:58

    Awesome article! I want people to know just how good this information is in your article. It’s interesting, compelling content. Your views are much like my own concerning this subject 먹튀검증 It touched me a lot. I would love to hear your opinion on my site. Please come to the site I run once and leave a comment. Thank you.


    ReplyDelete
  36. I am more curious to take an interest in some of them. I hope you will provide more information on these topics in your next articles.

    Cyber Security Training in Bangalore

    ReplyDelete
  37. 메이저놀이터26/11/21 22:37

    I’m very pleased to discover this site. I want to to thank you for ones time for this particularly wonderful read!! I definitely savored every part of it and i also have you saved as a favorite to see new information on your blog. 메이저놀이터


    ReplyDelete
  38. It’s nice to see this article.
    really amazing!
    I’ll be subscribing with your feed and I hope you publish once additional soon.

    ReplyDelete
  39. All you need to know about 바카라사이트! (10th Specialist CONFIRMED)

    ReplyDelete


  40. That's a really impressive new idea!
    블랙잭사이트


    I finally found what I was looking for! I'm so happy.
    블랙잭사이트

    ReplyDelete

  41. Thanks for sharing with us this important Content.
    슬롯사이트

    found exactly what I used to be having a look for.
    슬롯사이트

    ReplyDelete
  42. Sports are about physical strength, social skills, and teamwork
    It's an essential part of children's development
    Toto site that everyone can't help but like

    ReplyDelete