text: Title: Group Sparse Regularization for Deep Neural Networks
  Author(s): Scardapane, Simone
  Keywords: Deep networks
  Citation: Scardapane S, Comminiello D, Hussain A & Uncini A (2017) Group Sparse Regularization for Deep Neural Networks, Neurocomputing, 241, pp. 81-89.
  Abstract: In this paper, we address the challenging task of simultaneously optimizing (i) the weights of a neural network, (ii) the number of neurons for each hidden layer, and (iii) the subset of active input features (i.e., feature selection). While these problems are traditionally dealt with separately, we propose an efficient regularized formulation enabling their simultaneous parallel execution, using standard optimization routines. Specifically, we extend the group Lasso penalty, originally proposed in the linear regression literature, to impose group-level sparsity on the network's connections, where each group is defined as the set of outgoing weights from a unit. Depending on the specific case, the weights can be related to an input variable, to a hidden neuron, or to a bias unit, thus performing simultaneously all the aforementioned tasks in order to obtain a compact network. We carry out an extensive experimental evaluation, in comparison with classical weight decay and Lasso penalties, both on a toy dataset for handwritten digit recognition, and multiple realistic mid-scale classification benchmarks. Comparative results demonstrate the potential of our proposed sparse group Lasso penalty in producing extremely compact networks, with a significantly lower number of input features, with a classification accuracy which is equal or only slightly inferior to standard regularization terms.
  DOI Link: http://dx.doi.org/10.1016/j.neucom.2017.02.029
  Rights: This item has been embargoed for a period. During the embargo please use the Request a Copy feature at the foot of the Repository record to request a copy directly from the author. You can only request a copy if you wish to use this work for your own research or private study. Accepted refereed manuscript of: Scardapane S, Comminiello D, Hussain A & Uncini A (2017) Group Sparse Regularization for Deep Neural Networks, Neurocomputing, 241, pp. 81-89. DOI: 10.1016/j.neucom.2017.02.029 © 2017, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/