مقاله انگلیسی رایگان در مورد بهبود کارایی در شبکه های عصبی پیچشی با فیلترهای چند خطی – الزویر 2018

In recent years, deep neural network architectures have excelled in several application domains, ranging from machine vision [1, 2, 3], natural language processing [4, 5] to biomedical [6, 7] and financial data analysis [8, 9] . Of those important developments, Convolutional Neural Network (CNN) has evolved as a main workhorse in solving computer vision tasks nowadays. The architecture was originally developed in the 1990s for handwritten character recognition using only two convolutional layers [10]. Over the years, with the development of Graphical Processing Units (GPUs) and efficient implementation of convolution operation, the depth of CNNs has been increased to tackle more complicated problems. Nowadays, prominent architectures such as Residual Network (ResNet) [11] or Google Inception [12] with hundreds of layers have become saturated. Researchers started to wonder whether millions of parameters are essential to achieve such performance. In order to extend the benefit of such deep nets to embedded devices with limited computation power and memory, recent works have focused on reducing the memory footprint and computation of a pre-trained network, i.e. they apply network compression in the post-training stage. In fact, recent works have shown that traditional network architectures such as Alexnet, VGG or Inception are highly redundant structures [13, 14, 15, 16, 17, 18, 19, 20, 21, 22]. For example, in [13] a simple heuristic based on magnitude of the weights was employed to eliminate the connections in a pre-trained network, which achieved considerable amount of compression without hurting the performance much. Additionally, representing network parameters with low bitwidth numbers, like in [23, 24, 25], has shown that the performance of a 32-bit network can be closely retained with only 4-bit representations. It should be noted that the two approaches are complementary to each other. In fact, a compression pipeline called “Deep Compression” [13] which consists of three compression procedures, i.e. weight pruning, weight quantization and Huffman-based weight encoding, achieved excellent compression performance on AlexNet and VGG-16 architectures. Along pruning and quantization, low-rank approximation of both convolutional layers and fully connected layers was also employed to achieve computational speed up [26, 27, 28]. Viewed as high-order tensors, convolutional layers were decomposed using traditional tensor decomposition methods, such as CP decomposition [21, 20, 29] or Tucker decomposition [30], and the convolution operation is approximated by applying consecutive 1D convolutions. Overall, efforts to remove redundancy in already trained neural networks have shown promising results by determining networks with a much simpler structure. The results naturally pose the following question: why should we compress an already trained network and not seek for a compact network representation that can be trained from scratch?. Subsequently, one could of course exploit the above mentioned compression techniques to further decrease the cost.