Contents

DNN Foundations: Regularization, Dropout, and Overfitting Prevention

Overview

Essential concepts for building effective deep neural networks, with focus on regularization techniques and preventing overfitting.

Preventing Overfitting in DNNs

Regularization

Adding penalty terms to discourage large weights during training.

L1 Regularization

  • Formula: λ|w|
  • Encourages exact zeros in weights
  • Useful for automatic feature selection

L2 Regularization

  • Formula: λ·(1/2)w²
  • Continuous weight decay toward zero
  • More stable than L1 without collapsing to exact zeros

Max Norm Constraints

Restricting weight magnitudes to prevent them from growing too large.

Dropout

  • Randomly deactivating neurons during training (with probability p)
  • Prevents co-adaptation of neurons
  • Inverted dropout scales outputs by 1/p during training for consistent expected values

Based on “Fundamentals of Deep Learning” and refined through practical experience.