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

Overview of Dimensionality Reduction Techniques

The goal of any dimensionality reduction technique is to manage the sparsity of the dataset while keeping any useful information that is provided. In our case of classification, dimensionality reduction is typically used as an important preprocessing step used before the actual classification. Most dimensionality reduction techniques aim to complete this task using a process of feature projection, which adjusts the data from the higher-dimensional space into a space with fewer dimensions to remove the sparsity from the data. Again, as a means of visualizing the projection process, consider a sphere in a 3D space. We can project the sphere into a lower 2D space into a circle with some information loss (the value for the z coordinate), but retaining much of the information that describes its original shape. We still know the origin, radius, and manifold (outline) of the shape, and it is still very clear that it is a circle. So, depending...