1. MATLAB Implementation of the Optimal Brain Surgeon (OBS) Algorithm
by Mengu Sukan
December 10th, 2001
ECE 539: Intro to Artificial Neural Networks
Prof. Yu Hen Hu

2. Optimal Brain Surgeon (OBS) Algorithm
A network pruning technique
Minimizes network size while maintaining good performance
Advantages of smaller network
Calculation efficiency
Less affected by training noise, thus better generalization to new data

3. OBS in words Train multilayer perceptron to minimum square error
Calculate 2nd order-derivative of error surface – the inverse Hessian (matrix form)
Calculate saliency of each weight (saliency = the increase in error when deleting weight)
If saliency small enough, eliminate weight

4. OBS History Introduced by Hassibi in 1992 NETtalk perceptron (1987)
Text-to-speech engine
203 sensory, 80 hidden, 26 output
18,629 weights
Pruned to 1560 weights

5. MATLAB’s Suitability for OBS
Matrix based calculations
Familiarity with software
Availability of network training algorithm