Machine Learning

Machine Learning是什么

简单的理解就是在输入和输出中找一个函数

Different types of Functions
Different types of Functions

Deep Learning Introduce

history (Ups and downs of Deep Learning)

  • 1958: Perceptron (linear model)
  • 1969: Perceptron has limitation
  • 1980: Multi-layer perceptron
    • Do not have significant difference from DNN today
  • 1986: Backpropagation
    • Usually more than 3 hidden layers is not helpful
  • 1989: 1 hidden layer is “good enough”, why deep?
  • 2006: RBM initialization (breakthrough)
  • 2009: GPU
  • 2011: Start to be popular in speech recognition
  • 2012: win ILSVRC image competition

Fully Connect Feedforward Network

  • 输入叫Input Layer
  • 输出叫Output Layer
  • 中间层叫hidden Layers

Fully Connect Feedforward Network
Fully Connect Feedforward Network

Deep = Many hidden layers

  • AlexNet(2012), 8 layers, error rate: 16.4%
  • VGG(2014), 19 layers, error rate: 7.3%
  • GoogleNet(2014), 22 layers, error rate: 6.7%
  • Residual Net(2015), 152 layers, error rate: 3.57%

FAQ

  • Q: How many layers? How many neurons for each layer?
    • Trial and Error + Intuition
  • Q: Can the structure be automatically determined?
    • Evolutionary Artificial Neural Networks
  • Q: Can we design the network structure?
    • Convolutional Neural Network (CNN)
  • Q: Deeper is Better?
    • Universality Theorem
      • Any continuous function f
      • $ f : R^N \rightarrow R^M $
      • Can be realized by a network with one hidden layer (given enough hidden neurons)
      • Why Deep neural network not Fat neural network?

Reference

系列文档是国立台湾大学 李宏毅 老师Machine Learning系列教材的学习整理。

Reference Video

Nvidia Resources

Reference Book