Neural Networks

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Neural Networks
Neural Networks
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Neural Networks

• Supervised Learning
• Multilayer perceptrons
• Radial basis function networks
• Modular neural networks
• LVQ (learning vector quantization)
• Unsupervised Learning
• Competitive learning networks
• Kohonen self-organizing networks
• ART (adaptive resonant theory)
• Others
• Hopfield networks

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Adaptive Networks
x
z
y

• Architecture
• Feedforward networks with diff. node functions
• Squares nodes with parameters
• Circles nodes without parameters
• Goal
• To achieve an I/O mapping specified by training
  data
• Basic training method
• Backpropagation or steepest descent

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Single-Layer Perceptrons

• Network architecture

x1
w1
w0
w2
x2
y signum(Swi xi w0)
w3
x3
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Single-Layer Perceptrons

• Example Gender classification

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Multilayer Perceptrons (MLPs)

• Learning rule
• Steepest descent (Backprop)
• Conjugate gradient method
• All optim. methods using first derivative
• Derivative-free optim.

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Multilayer Perceptrons (MLPs)
Example XOR problem
Training data
x1 x2 y 0 0 0 0 1 1 1 0 1 1
1 0
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MLP Decision Boundaries