Book Image

Hands-On Unsupervised Learning with Python

By : Giuseppe Bonaccorso
Book Image

Hands-On Unsupervised Learning with Python

By: Giuseppe Bonaccorso

Overview of this book

Unsupervised learning is about making use of raw, untagged data and applying learning algorithms to it to help a machine predict its outcome. With this book, you will explore the concept of unsupervised learning to cluster large sets of data and analyze them repeatedly until the desired outcome is found using Python. This book starts with the key differences between supervised, unsupervised, and semi-supervised learning. You will be introduced to the best-used libraries and frameworks from the Python ecosystem and address unsupervised learning in both the machine learning and deep learning domains. You will explore various algorithms, techniques that are used to implement unsupervised learning in real-world use cases. You will learn a variety of unsupervised learning approaches, including randomized optimization, clustering, feature selection and transformation, and information theory. You will get hands-on experience with how neural networks can be employed in unsupervised scenarios. You will also explore the steps involved in building and training a GAN in order to process images. By the end of this book, you will have learned the art of unsupervised learning for different real-world challenges.
Table of Contents (12 chapters)

Summary

In this chapter, we have presented some of the most important clustering algorithms that can be employed to solve non-convex problems. Spectral clustering is a very popular technique that performs a projection of the dataset onto a new space where concave geometries become convex and a standard algorithm such as K-means can easily segment the data.

Conversely, mean shift and DBSCAN analyze the density of the dataset and try to split it so that all dense and connected regions are merged together to make up the clusters. In particular, DBSCAN is very efficient in very irregular contexts because it's based on local nearest neighbors sets that are concatenated until the separation overcomes a predefined threshold. In this way, the algorithm can solve many specific clustering problems with the only drawback being that it also yields a set of noise points that cannot be...