4、Neural Networks
4.1 Motivations
Neural Networks
Origins: Algorithms that try to mimic the brain.
Was very widely used in 80s and early 90s;
popularity diminished in late 90s.
Recent resurgence:
state-of-the-art technique for many applications.
4.2 Neural Networks
4.2.1 Model Representation I
Sigmoid(logistic) activation function.
4.2.2 Model Representation II
input层
hidden层
output层
4.3 Multiple output units:One-vs-all.
