1,472 research outputs found
A survey on modern trainable activation functions
In neural networks literature, there is a strong interest in identifying and
defining activation functions which can improve neural network performance. In
recent years there has been a renovated interest of the scientific community in
investigating activation functions which can be trained during the learning
process, usually referred to as "trainable", "learnable" or "adaptable"
activation functions. They appear to lead to better network performance.
Diverse and heterogeneous models of trainable activation function have been
proposed in the literature. In this paper, we present a survey of these models.
Starting from a discussion on the use of the term "activation function" in
literature, we propose a taxonomy of trainable activation functions, highlight
common and distinctive proprieties of recent and past models, and discuss main
advantages and limitations of this type of approach. We show that many of the
proposed approaches are equivalent to adding neuron layers which use fixed
(non-trainable) activation functions and some simple local rule that
constraints the corresponding weight layers.Comment: Published in "Neural Networks" journal (Elsevier
Why and When Can Deep -- but Not Shallow -- Networks Avoid the Curse of Dimensionality: a Review
The paper characterizes classes of functions for which deep learning can be
exponentially better than shallow learning. Deep convolutional networks are a
special case of these conditions, though weight sharing is not the main reason
for their exponential advantage
Kervolutional Neural Networks
Convolutional neural networks (CNNs) have enabled the state-of-the-art
performance in many computer vision tasks. However, little effort has been
devoted to establishing convolution in non-linear space. Existing works mainly
leverage on the activation layers, which can only provide point-wise
non-linearity. To solve this problem, a new operation, kervolution (kernel
convolution), is introduced to approximate complex behaviors of human
perception systems leveraging on the kernel trick. It generalizes convolution,
enhances the model capacity, and captures higher order interactions of
features, via patch-wise kernel functions, but without introducing additional
parameters. Extensive experiments show that kervolutional neural networks (KNN)
achieve higher accuracy and faster convergence than baseline CNN.Comment: oral paper in CVPR 201
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