Book Image

R Machine Learning Essentials

By : Michele Usuelli
Book Image

R Machine Learning Essentials

By: Michele Usuelli

Overview of this book

Table of Contents (15 chapters)
R Machine Learning Essentials
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Perceptron


Artificial Neural Networks (ANN) are the supervised learning techniques whose logic is similar to biological neural systems. A simple ANN technique is the single-layer perceptron and it is a classification technique estimating a binary attribute whose value can be 0 or 1. The perceptron works like a neuron in the sense that it sums the impact of all the inputs and outputs to 1 if the sum is above a defined threshold. The model is based on the following parameters:

  • A weight for each feature, defining its impact

  • A threshold above which the estimated output is 1

Starting from the features, the model estimates the attribute through these steps

  • Compute the output through a linear regression: multiply each feature by its weight and sum all of them

  • Estimate the attribute to 1 if the output is above the threshold and to 0 otherwise

The models are as shown in the following figure:

In the beginning, the algorithm builds the perceptron with a defined set of coefficients and with a threshold. Then...