4,704 research outputs found
Deep Neural Network Architectures for Modulation Classification
In this work, we investigate the value of employing deep learning for the
task of wireless signal modulation recognition. Recently in [1], a framework
has been introduced by generating a dataset using GNU radio that mimics the
imperfections in a real wireless channel, and uses 10 different modulation
types. Further, a convolutional neural network (CNN) architecture was developed
and shown to deliver performance that exceeds that of expert-based approaches.
Here, we follow the framework of [1] and find deep neural network architectures
that deliver higher accuracy than the state of the art. We tested the
architecture of [1] and found it to achieve an accuracy of approximately 75% of
correctly recognizing the modulation type. We first tune the CNN architecture
of [1] and find a design with four convolutional layers and two dense layers
that gives an accuracy of approximately 83.8% at high SNR. We then develop
architectures based on the recently introduced ideas of Residual Networks
(ResNet [2]) and Densely Connected Networks (DenseNet [3]) to achieve high SNR
accuracies of approximately 83.5% and 86.6%, respectively. Finally, we
introduce a Convolutional Long Short-term Deep Neural Network (CLDNN [4]) to
achieve an accuracy of approximately 88.5% at high SNR.Comment: 5 pages, 10 figures, In proc. Asilomar Conference on Signals,
Systems, and Computers, Nov. 201
Multi-Scale Attention with Dense Encoder for Handwritten Mathematical Expression Recognition
Handwritten mathematical expression recognition is a challenging problem due
to the complicated two-dimensional structures, ambiguous handwriting input and
variant scales of handwritten math symbols. To settle this problem, we utilize
the attention based encoder-decoder model that recognizes mathematical
expression images from two-dimensional layouts to one-dimensional LaTeX
strings. We improve the encoder by employing densely connected convolutional
networks as they can strengthen feature extraction and facilitate gradient
propagation especially on a small training set. We also present a novel
multi-scale attention model which is employed to deal with the recognition of
math symbols in different scales and save the fine-grained details that will be
dropped by pooling operations. Validated on the CROHME competition task, the
proposed method significantly outperforms the state-of-the-art methods with an
expression recognition accuracy of 52.8% on CROHME 2014 and 50.1% on CROHME
2016, by only using the official training dataset
Multi-scale Multi-band DenseNets for Audio Source Separation
This paper deals with the problem of audio source separation. To handle the
complex and ill-posed nature of the problems of audio source separation, the
current state-of-the-art approaches employ deep neural networks to obtain
instrumental spectra from a mixture. In this study, we propose a novel network
architecture that extends the recently developed densely connected
convolutional network (DenseNet), which has shown excellent results on image
classification tasks. To deal with the specific problem of audio source
separation, an up-sampling layer, block skip connection and band-dedicated
dense blocks are incorporated on top of DenseNet. The proposed approach takes
advantage of long contextual information and outperforms state-of-the-art
results on SiSEC 2016 competition by a large margin in terms of
signal-to-distortion ratio. Moreover, the proposed architecture requires
significantly fewer parameters and considerably less training time compared
with other methods.Comment: to appear at WASPAA 201
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