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

Hebb's rule


Hebb's rule has been proposed as a conjecture in 1949 by the Canadian psychologist Donald Hebb to describe the synaptic plasticity of natural neurons. A few years after its publication, this rule was confirmed by neurophysiological studies, and many research studies have shown its validity in many application, of Artificial Intelligence. Before introducing the rule, it's useful to describe the generic Hebbian neuron, as shown in the following diagram:

Generic Hebbian neuron with a vectorial input

The neuron is a simple computational unit that receives an input vector x, from the pre-synaptic units (other neurons or perceptive systems) and outputs a single scalar value, y. The internal structure of the neuron is represented by a weight vector, w, that models the strength of each synapse. For a single multi-dimensional input, the output is obtained as follows: 

In this model, we are assuming that each input signal is encoded in the corresponding component of the vector, x; therefore...