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

Chapter 5. EM Algorithm and Applications

In this chapter, we are going to introduce a very important algorithmic framework for many statistical learning tasks: the EM algorithm. Contrary to its name, this is not a method to solve a single problem, but a methodology that can be applied in several contexts. Our goal is to explain the rationale and show the mathematical derivation, together with some practical examples. In particular, we are going to discuss the following topics:

  • Maximum Likelihood Estimation (MLE) and Maximum A Posteriori (MAP) learning approaches
  • The EM algorithm with a simple application for the estimation of unknown parameters
  • The Gaussian mixture algorithm, which is one the most famous EM applications
  • Factor analysis
  • Principal Component Analysis (PCA)
  • Independent Component Analysis (ICA)
  • A brief explanation of the Hidden Markov Models (HMMs) forward-backward algorithm considering the EM steps