R Deep Learning Essentials - Second Edition

Deep neural networks

A deep neural network (DNN) is a neural network with multiple hidden layers. We cannot achieve good results by just increasing the number of nodes in a neural network with a small number of layers (a shallow neural network). A DNN can fit data more accurately with fewer parameters than a shallow neural network (NN), because more layers (each with fewer neurons) give a more efficient and accurate representation. Using multiple hidden layers allows a more sophisticated build-up from simple elements to more complex ones. In the previous example, we considered a neural network that could recognize basic shapes, such as a circle or a square. In a deep neural network, many circles and squares could be combined to form other, ...