Book Image

The Unsupervised Learning Workshop

By : Aaron Jones, Christopher Kruger, Benjamin Johnston
Book Image

The Unsupervised Learning Workshop

By: Aaron Jones, Christopher Kruger, Benjamin Johnston

Overview of this book

Do you find it difficult to understand how popular companies like WhatsApp and Amazon find valuable insights from large amounts of unorganized data? The Unsupervised Learning Workshop will give you the confidence to deal with cluttered and unlabeled datasets, using unsupervised algorithms in an easy and interactive manner. The book starts by introducing the most popular clustering algorithms of unsupervised learning. You'll find out how hierarchical clustering differs from k-means, along with understanding how to apply DBSCAN to highly complex and noisy data. Moving ahead, you'll use autoencoders for efficient data encoding. As you progress, you’ll use t-SNE models to extract high-dimensional information into a lower dimension for better visualization, in addition to working with topic modeling for implementing natural language processing (NLP). In later chapters, you’ll find key relationships between customers and businesses using Market Basket Analysis, before going on to use Hotspot Analysis for estimating the population density of an area. By the end of this book, you’ll be equipped with the skills you need to apply unsupervised algorithms on cluttered datasets to find useful patterns and insights.
Table of Contents (11 chapters)
Preface

Principal Component Analysis

As described previously, PCA is a commonly used and very effective dimensionality reduction technique, which often forms a preprocessing stage for a number of machine learning models and techniques. For this reason, we will dedicate this section of the book to looking at PCA in more detail than any of the other methods. PCA reduces the sparsity in the dataset by separating the data into a series of components where each component represents a source of information within the data. As its name suggests, the first component produced in PCA, the principal component, comprises the majority of information or variance within the data. The principal component can often be thought of as contributing the most amount of interesting information in addition to the mean. With each subsequent component, less information, but more subtlety, is contributed to the compressed data. If we consider all of these components together, there will be no benefit of using PCA, as...