neural networks - seoul national...
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Neural Networks이경호
Movement research lab
Introduction
• Neural network basics
• Convolutional Neural Networks
• Recurrent Neural Networks
Supervised Learning
Linear Classification
ax + by + c > 0
Multiple classifier
Perceptron
Feed-forward Neural Network
Feed-forward Neural Network
Feed-forward Neural Network
𝑊0 𝑊1𝑊2
( n = 3, h = 4, m = 1 )
Loss function
Regression Regularization
Backpropagation
f(x,y,z) = (x + y)*z
Backpropagation
Optimization
• Gradient Descent
• Adam optimizer
• Mini-batch
Applications
• Motion generation• Predict next frame
• Deep RL• Represents policy, value function
Image Classification
• Multi-dimensional structure( width x height x color )
• High-dimensional data ( 128 x 128 x 3 = 49152 )
- Car- Airplane- Ship- Bike
?
Convolutional Neural Network
• Local Connectivity
• Parameter Sharing
• Pooling layer ( Subsampling )
Convolutional Neural Network
Kernel convolution
6x6 Input
3x3 Filter
17sum
Conv2d
Input n X n Filter m x m
Conv2d Output n X n
Conv2d
Input n * n Filter m * m
Conv2d Output n * n
Input n * n * k Filter m * m * k
Conv2d Output n * n
Max pooling
Strided convolutions
Strided convolutions
Convolutional Neural Network
Convolutional Neural Network
(256x256x3)
Filter Size = 5x5
Convolutional Neural Network
(256x256x3)
Filter Size = 5x5
L1 = (5x5x3) x 4
(256x256x4)
Convolutional Neural Network
(256x256x3)
Filter Size = 5x5
F1 = (5x5x3) x 4
(256x256x4)
F2 = (5x5x4) x 8
(128x128x4) (128x128x8)
Convolutional Neural Network
(256x256x3)
Filter Size = 5x5
F1 = (5x5x3) x 4= 300
(256x256x4)
F2 = (5x5x4) x 8= 800
(128x128x4) (128x128x8) (64x64x8)
(32687 x h)
CNN in Character animation
• Conv1d in time dimension
Filter3x50
Input11 x 50
CNN in Character animation
• Conv1d in time dimension
Filter3x50
Input11 x 50
CNN in Character animation
• Environment model
CNN in Character animation
Recurrent Neural Network
He likes apples.
그는 사과를 좋아한다.
Feed-forward Neural Network
𝑊
𝑥
𝑦
x1
x2
x3
y1
y2
𝑤𝑖𝑗
Recurrent Neural Network
Recurrent Neural Network
Truncated back propagation through time (BPTT)
* Vanishing gradients problem
Long Short-Term Memory(LSTM)
Types of RNN
Types of RNN
Motion recognition Motion prediction Motion generation