Book Image

R Deep Learning Essentials. - Second Edition

By : Mark Hodnett, Joshua F. Wiley
Book Image

R Deep Learning Essentials. - Second Edition

By: Mark Hodnett, Joshua F. Wiley

Overview of this book

Deep learning is a powerful subset of machine learning that is very successful in domains such as computer vision and natural language processing (NLP). This second edition of R Deep Learning Essentials will open the gates for you to enter the world of neural networks by building powerful deep learning models using the R ecosystem. This book will introduce you to the basic principles of deep learning and teach you to build a neural network model from scratch. As you make your way through the book, you will explore deep learning libraries, such as Keras, MXNet, and TensorFlow, and create interesting deep learning models for a variety of tasks and problems, including structured data, computer vision, text data, anomaly detection, and recommendation systems. You’ll cover advanced topics, such as generative adversarial networks (GANs), transfer learning, and large-scale deep learning in the cloud. In the concluding chapters, you will learn about the theoretical concepts of deep learning projects, such as model optimization, overfitting, and data augmentation, together with other advanced topics. By the end of this book, you will be fully prepared and able to implement deep learning concepts in your research work or projects.
Table of Contents (13 chapters)

Using auto-encoders for anomaly detection

Now that we have built an auto-encoder and accessed the features of the inner layers, we will move on to an example of how auto-encoders can be used for anomaly detection. The premise here is quite simple: we take the reconstructed outputs from the decoder and see which instances have the most error, that is, which instances are the most difficult for the decoder to reconstruct. The code that is used here is in Chapter9/anomaly.R, and we will be using the UCI HAR dataset that we have already been introduced to in Chapter 2, Training a Prediction Model. If you have not already downloaded the data, go back to that chapter for instructions on how to do so.. The first part of the code loads the data, and we subset the features to only use the ones with mean, sd, and skewness in the feature names:

train.x <...