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)

Introduction to Data Imbalance in Machine Learning

Machine learning algorithms have helped solve real-world problems as diverse as disease prediction and online shopping. However, many problems we would like to address with machine learning involve imbalanced datasets. In this chapter, we will discuss and define imbalanced datasets, explaining how they differ from other types of datasets. The ubiquity of imbalanced data will be demonstrated with examples of common problems and scenarios. We will also go through the basics of machine learning and cover the essentials, such as loss functions, regularization, and feature engineering. We will also learn about common evaluation metrics, particularly those that can be very helpful for imbalanced datasets. We will then introduce the imbalanced-learn library.

In particular, we will learn about the following topics:

  • Introduction to imbalanced datasets
  • Machine learning 101
  • Types of datasets and splits
  • Common evaluation metrics
  • Challenges and considerations when dealing with imbalanced data
  • When can we have an imbalance in datasets?
  • Why can imbalanced data be a challenge?
  • When to not worry about data imbalance
  • Introduction to the imbalanced-learn library
  • General rules to follow