Book Image

Applied Unsupervised Learning with Python

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

Applied Unsupervised Learning with Python

By: Benjamin Johnston, Aaron Jones, Christopher Kruger

Overview of this book

Unsupervised learning is a useful and practical solution in situations where labeled data is not available. Applied Unsupervised Learning with Python guides you in learning the best practices for using unsupervised learning techniques in tandem with Python libraries and extracting meaningful information from unstructured data. The book begins by explaining how basic clustering works to find similar data points in a set. Once you are well-versed with the k-means algorithm and how it operates, you’ll learn what dimensionality reduction is and where to apply it. As you progress, you’ll learn various neural network techniques and how they can improve your model. While studying the applications of unsupervised learning, you will also understand how to mine topics that are trending on Twitter and Facebook and build a news recommendation engine for users. Finally, you will be able to put your knowledge to work through interesting activities such as performing a Market Basket Analysis and identifying relationships between different products. By the end of this book, you will have the skills you need to confidently build your own models using Python.
Table of Contents (12 chapters)
Applied Unsupervised Learning with Python
Preface

Kernel Density Estimation


One of the main methodological approaches to hotspot analysis is kernel density estimation. Kernel density estimation builds an estimated density using sample data and two parameters known as the kernel function and the bandwidth value. The estimated density is, like any distribution, essentially a guideline for the behavior of a random variable. Here, we mean how frequently the random variable takes on any specific value, . When dealing with hotspot analysis where the data is typically geographic, the estimated density answers the question How frequently do specific longitude and latitude pairs appear?. If a specific longitude and latitude pair, , and other nearby pairs occur with high frequency, then the estimated density built using the sample data will be expected to show that the area around the longitude and latitude pair has a high likelihood.

Kernel density estimation is referred to as a smoothing algorithm, because the process of estimating a density is...