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)

Exercises

  1. Explore the various undersampling APIs available from the imbalanced-learn library at https://imbalanced-learn.org/stable/references/under_sampling.html.
  2. Explore the NearMiss undersampling technique, available through the imblearn.under_sampling.NearMiss API. Which class of methods does it belong to? Apply the NearMiss method to the dataset that we used in the chapter.
  3. Try all the undersampling methods discussed in this chapter on the us_crime dataset from UCI. You can find this dataset in the fetch_datasets API of the imbalanced-learn library. Find the undersampling method with the highest f1-score metric for LogisticRegression and XGBoost models.
  4. Can you identify an undersampling method of your own? (Hint: think about combining the various approaches to undersampling in new ways.)