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)

Discussion of other data-level deep learning methods and their key ideas

In addition to the methods previously discussed, there is a rich array of other techniques specifically designed to address imbalanced data challenges. This section provides a high-level overview of these alternative approaches, each offering unique insights and potential advantages. While we will only touch upon their key ideas, we encourage you to delve deeper into the literature and explore them further if you find these techniques intriguing.

Two-phase learning

Two-phase learning [16][17] is a technique designed to enhance the performance of minority classes in multi-class classification problems, without compromising the performance of majority classes. The process involves two training phases:

  1. In the first phase, a deep learning model is first trained on the dataset, which is balanced with respect to each class. Balancing can be done using sampling techniques such as random oversampling or...