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)

Chapter 6 – Data Imbalance in Deep Learning

  1. The main challenge stems from the different types of data these models handle. Classical machine learning models typically work with structured, tabular data, while deep learning models handle unstructured data such as images, text, audio, and video.
  2. An imbalanced version of the MNIST dataset can be created by randomly selecting a certain percentage of examples for each class. This process involves choosing indices of the samples to remove and then actually removing these samples from the training set.
  3. This has been left as an exercise for you.
  4. Random oversampling is used to address imbalance in the dataset. It works by duplicating samples from the minority classes until each class has an equal number of samples. This technique is usually considered to perform better than no sampling.
  5. Data augmentation techniques can include rotating, scaling, cropping, blurring, adding noise to the image, and much more. However...