Book Image

Mastering Machine Learning Algorithms. - Second Edition

By : Giuseppe Bonaccorso
Book Image

Mastering Machine Learning Algorithms. - Second Edition

By: Giuseppe Bonaccorso

Overview of this book

Mastering Machine Learning Algorithms, Second Edition helps you harness the real power of machine learning algorithms in order to implement smarter ways of meeting today's overwhelming data needs. This newly updated and revised guide will help you master algorithms used widely in semi-supervised learning, reinforcement learning, supervised learning, and unsupervised learning domains. You will use all the modern libraries from the Python ecosystem – including NumPy and Keras – to extract features from varied complexities of data. Ranging from Bayesian models to the Markov chain Monte Carlo algorithm to Hidden Markov models, this machine learning book teaches you how to extract features from your dataset, perform complex dimensionality reduction, and train supervised and semi-supervised models by making use of Python-based libraries such as scikit-learn. You will also discover practical applications for complex techniques such as maximum likelihood estimation, Hebbian learning, and ensemble learning, and how to use TensorFlow 2.x to train effective deep neural networks. By the end of this book, you will be ready to implement and solve end-to-end machine learning problems and use case scenarios.
Table of Contents (28 chapters)
26
Other Books You May Enjoy
27
Index

Fuzzy C-means

We have already talked about the difference between hard and soft clustering, comparing K-means with Gaussian mixtures. Another way to address this problem is based on the concept of fuzzy logic, which was proposed for the first time by Lotfi Zadeh in 1965 (for further details, a very good reference is Pedrycz W., Gomide F., An Introduction to Fuzzy Sets, The MIT Press, 1998). Classic logic sets are based on the law of excluded middle, which in a clustering scenario can be expressed by saying that a point can belong only to a single cluster cj.

Speaking more generally, if we split our universe into labeled partitions, a hard clustering approach would assign a label to each sample, while a fuzzy (or soft) approach would allow the management of a membership degree (in Gaussian mixtures, this is an actual probability) wij, which expresses how strong the relationship is between point and cluster cj.

Contrary to other methods, by employing fuzzy logic it's possible...