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Multi Layer Perceptron Computer & Robot Vision Lab Sung -ju Kim [email protected]
18

Multi Layer Perceptron & Back Propagation

Apr 12, 2017

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Sung-ju Kim
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Page 1: Multi Layer Perceptron & Back Propagation

Multi Layer PerceptronComputer & Robot Vision Lab

Sung -ju Kim [email protected]

Page 2: Multi Layer Perceptron & Back Propagation

Content

• Why Neural Net came back?

• Single Layer Perceptron

• Multi Layer Perceptron

• Traffic Sign Lane Guessing

Page 3: Multi Layer Perceptron & Back Propagation

Why Neural Net Came back?

Stallkamp, Johannes, et al. "Man vs. computer: Benchmarking machine learning algorithms for traffic sign recognition." Neural networks 32 (2012): 323-332.

Face net: 99.6% Deep Face : 97.25%

Page 4: Multi Layer Perceptron & Back Propagation

Single Layer PerceptronFeed Forward

Page 5: Multi Layer Perceptron & Back Propagation

Activation Functionsstep function sign function identity function

sigmoid function hyper tangent function

Page 6: Multi Layer Perceptron & Back Propagation

Limitation of Single Layer Perceptron

But Single Layer Perceptron cannot classify XOR Problem

Page 7: Multi Layer Perceptron & Back Propagation

Multi Layer Perceptron

Page 8: Multi Layer Perceptron & Back Propagation

Multi Layer Perceptron

Hidden Layer

Output Layer

Input Layer

Page 9: Multi Layer Perceptron & Back Propagation

Ex)

✕✕

Feed Forward

Page 10: Multi Layer Perceptron & Back Propagation

How to Learn Perceptron?Error Function

Error Function

Target Value

Output Value

Page 11: Multi Layer Perceptron & Back Propagation

How to Learn Perceptron?Delta Learning Rule

E

(weight)

Page 12: Multi Layer Perceptron & Back Propagation

How to Learn Perceptron?Delta Learning Rule

new weightcurrent weightlearning rateError Function

Page 13: Multi Layer Perceptron & Back Propagation

How to Learn Perceptron?Delta Learning Rule

E

(weight)

new weightcurrent weightlearning rateError Function

Page 14: Multi Layer Perceptron & Back Propagation

Back Propagation

Hidden Layer

Output Layer

Input Layer

Page 15: Multi Layer Perceptron & Back Propagation

new weight

current weight

learning rate

Error Function

Target Value

Output Value

Page 16: Multi Layer Perceptron & Back Propagation

Back Propagation

Hidden Layer

Output Layer

Input Layer

Page 17: Multi Layer Perceptron & Back Propagation

new weight

current weight

learning rate

Error Function

Page 18: Multi Layer Perceptron & Back Propagation

Good for Design in Parallels Architecture