Book Image

Mastering Machine Learning Algorithms

Book Image

Mastering Machine Learning Algorithms

Overview of this book

Machine learning is a subset of AI that aims to make modern-day computer systems smarter and more intelligent. The real power of machine learning resides in its algorithms, which make even the most difficult things capable of being handled by machines. However, with the advancement in the technology and requirements of data, machines will have to be smarter than they are today to meet the overwhelming data needs; mastering these algorithms and using them optimally is the need of the hour. Mastering Machine Learning Algorithms is your complete guide to quickly getting to grips with popular machine learning algorithms. You will be introduced to the most widely used algorithms in supervised, unsupervised, and semi-supervised machine learning, and will learn how to use them in the best possible manner. Ranging from Bayesian models to the MCMC algorithm to Hidden Markov models, this book will teach you how to extract features from your dataset and perform dimensionality reduction by making use of Python-based libraries such as scikit-learn v0.19.1. You will also learn how to use Keras and TensorFlow 1.x to train effective neural networks. If you are looking for a single resource to study, implement, and solve end-to-end machine learning problems and use-cases, this is the book you need.
Table of Contents (22 chapters)
Title Page
Dedication
Packt Upsell
Contributors
Preface
13
Deep Belief Networks
Index

MRF


Let's consider a set of random variables, xi, organized in an undirected graph, G=(V, E), as shown in the following diagram: 

 Example of a probabilistic undirected graph

Two random variables, a and b, are conditionally independent given the random variable, c if:

Now, consider the graph again; if all generic couples of subsets of variables Si and Sj are conditionally independent given a separating subset, Sk (so that all connections between variables belonging to Si to variables belonging to Sj pass through Sk), the graph is called a Markov random field (MRF). 

Given G=(V, E), a subset containing vertices such that every couple is adjacent is called a clique (the set of all cliques is often denoted as cl(G)). For example, consider the graph shown previously; (x0, x1) is a clique and if x0 and x5 were connected, (x0, x1, x5) would be a clique. A maximal clique is a clique that cannot be expanded by adding new vertices. A particular family of MRF is made up of all those graphs whose joint...