Book Image

Machine Learning for Imbalanced Data

By : Kumar Abhishek, Dr. Mounir Abdelaziz
Book Image

Machine Learning for Imbalanced Data

By: Kumar Abhishek, Dr. Mounir Abdelaziz

Overview of this book

As machine learning practitioners, we often encounter imbalanced datasets in which one class has considerably fewer instances than the other. Many machine learning algorithms assume an equilibrium between majority and minority classes, leading to suboptimal performance on imbalanced data. This comprehensive guide helps you address this class imbalance to significantly improve model performance. Machine Learning for Imbalanced Data begins by introducing you to the challenges posed by imbalanced datasets and the importance of addressing these issues. It then guides you through techniques that enhance the performance of classical machine learning models when using imbalanced data, including various sampling and cost-sensitive learning methods. As you progress, you’ll delve into similar and more advanced techniques for deep learning models, employing PyTorch as the primary framework. Throughout the book, hands-on examples will provide working and reproducible code that’ll demonstrate the practical implementation of each technique. By the end of this book, you’ll be adept at identifying and addressing class imbalances and confidently applying various techniques, including sampling, cost-sensitive techniques, and threshold adjustment, while using traditional machine learning or deep learning models.
Table of Contents (15 chapters)

Discussing other algorithm-based techniques

In this section, we’ll explore a diverse set of algorithm-level techniques that we haven’t covered so far. Intriguingly, these methods – from regularization techniques that mitigate overfitting to Siamese networks skilled in one-shot and few-shot learning, to deeper neural architectures and threshold adjustments – also have a beneficial side effect: they can occasionally mitigate the impact of class imbalance.

Regularization techniques

The paper from S. Alshammari et al. [14] found that well-known regularization techniques such as L2-regularization and the MaxNorm constraint are quite helpful in long-tailed recognition. The paper proposes to do these only at the last layer of classification (sigmoid or softmax, for example). Here are their findings:

  • L2-regularization (also called weight decay) generally keeps the weights in check and helps the model generalize better by preventing the model from overfitting...