Last Updated on August 6, 2019 Deep learning neural networks are likely to quickly overfit a training dataset with few examples. Ensembles of neural networks with different model configurations are known to reduce overfitting, but require the additional computational expense of training and maintaining multiple models. A single model can be used to simulate having a large number of different network architectures by randomly dropping out nodes during training. This is called dropout and offers a very computationally cheap and […]

Last Updated on August 25, 2020 Dropout regularization is a computationally cheap way to regularize a deep neural network. Dropout works by probabilistically removing, or “dropping out,” inputs to a layer, which may be input variables in the data sample or activations from a previous layer. It has the effect of simulating a large number of networks with very different network structure and, in turn, making nodes in the network generally more robust to the inputs. In this tutorial, you […]

Last Updated on August 6, 2019 A major challenge in training neural networks is how long to train them. Too little training will mean that the model will underfit the train and the test sets. Too much training will mean that the model will overfit the training dataset and have poor performance on the test set. A compromise is to train on the training dataset but to stop training at the point when performance on a validation dataset starts to […]

Last Updated on August 25, 2020 A problem with training neural networks is in the choice of the number of training epochs to use. Too many epochs can lead to overfitting of the training dataset, whereas too few may result in an underfit model. Early stopping is a method that allows you to specify an arbitrary large number of training epochs and stop training once the model performance stops improving on a hold out validation dataset. In this tutorial, you […]

Last Updated on August 6, 2019 Training a neural network with a small dataset can cause the network to memorize all training examples, in turn leading to overfitting and poor performance on a holdout dataset. Small datasets may also represent a harder mapping problem for neural networks to learn, given the patchy or sparse sampling of points in the high-dimensional input space. One approach to making the input space smoother and easier to learn is to add noise to inputs […]

Last Updated on August 28, 2020 Adding noise to an underconstrained neural network model with a small training dataset can have a regularizing effect and reduce overfitting. Keras supports the addition of Gaussian noise via a separate layer called the GaussianNoise layer. This layer can be used to add noise to an existing model. In this tutorial, you will discover how to add noise to deep learning models in Keras in order to reduce overfitting and improve model generalization. After […]

Last Updated on August 6, 2019 Training a deep neural network that can generalize well to new data is a challenging problem. A model with too little capacity cannot learn the problem, whereas a model with too much capacity can learn it too well and overfit the training dataset. Both cases result in a model that does not generalize well. A modern approach to reducing generalization error is to use a larger model that may be required to use regularization […]

Last Updated on August 6, 2019 How to Improve Performance By Combining Predictions From Multiple Models. Deep learning neural networks are nonlinear methods. They offer increased flexibility and can scale in proportion to the amount of training data available. A downside of this flexibility is that they learn via a stochastic training algorithm which means that they are sensitive to the specifics of the training data and may find a different set of weights each time they are trained, which […]

Last Updated on August 28, 2020 Deep learning neural network models are highly flexible nonlinear algorithms capable of learning a near infinite number of mapping functions. A frustration with this flexibility is the high variance in a final model. The same neural network model trained on the same dataset may find one of many different possible “good enough” solutions each time it is run. Model averaging is an ensemble learning technique that reduces the variance in a final neural network […]

Last Updated on August 25, 2020 Ensemble learning are methods that combine the predictions from multiple models. It is important in ensemble learning that the models that comprise the ensemble are good, making different prediction errors. Predictions that are good in different ways can result in a prediction that is both more stable and often better than the predictions of any individual member model. One way to achieve differences between models is to train each model on a different subset […]