4,321 research outputs found
Distributed Full-duplex via Wireless Side Channels: Bounds and Protocols
In this paper, we study a three-node full-duplex network, where a base
station is engaged in simultaneous up- and downlink communication in the same
frequency band with two half-duplex mobile nodes. To reduce the impact of
inter- node interference between the two mobile nodes on the system capacity,
we study how an orthogonal side-channel between the two mobile nodes can be
leveraged to achieve full-duplex-like multiplexing gains. We propose and
characterize the achievable rates of four distributed full-duplex schemes,
labeled bin-and- cancel, compress-and-cancel, estimate-and-cancel and decode-
and-cancel. Of the four, bin-and-cancel is shown to achieve within 1 bit/s/Hz
of the capacity region for all values of channel parameters. In contrast, the
other three schemes achieve the near-optimal performance only in certain
regimes of channel values. Asymptotic multiplexing gains of all proposed
schemes are derived to show that the side-channel is extremely effective in
regimes where inter-node interference has the highest impact.Comment: Published in IEEE Transactions on Wireless Communications, August
201
Modulating Image Restoration with Continual Levels via Adaptive Feature Modification Layers
In image restoration tasks, like denoising and super resolution, continual
modulation of restoration levels is of great importance for real-world
applications, but has failed most of existing deep learning based image
restoration methods. Learning from discrete and fixed restoration levels, deep
models cannot be easily generalized to data of continuous and unseen levels.
This topic is rarely touched in literature, due to the difficulty of modulating
well-trained models with certain hyper-parameters. We make a step forward by
proposing a unified CNN framework that consists of few additional parameters
than a single-level model yet could handle arbitrary restoration levels between
a start and an end level. The additional module, namely AdaFM layer, performs
channel-wise feature modification, and can adapt a model to another restoration
level with high accuracy. By simply tweaking an interpolation coefficient, the
intermediate model - AdaFM-Net could generate smooth and continuous restoration
effects without artifacts. Extensive experiments on three image restoration
tasks demonstrate the effectiveness of both model training and modulation
testing. Besides, we carefully investigate the properties of AdaFM layers,
providing a detailed guidance on the usage of the proposed method.Comment: Accepted by CVPR 2019 (oral); code is available:
https://github.com/hejingwenhejingwen/AdaF
Continuum Observations at 350 Microns of High-Redshift Molecular Emission Line Galaxies
We report observations of 15 high redshift (z = 1-5) galaxies at 350 microns
using the Caltech Submillimeter Observatory and SHARC-II array detector.
Emission was detected from eight galaxies, for which far-infrared luminosities,
star formation rates, total dust masses, and minimum source size estimates are
derived. These galaxies have star formation rates and star formation
efficiencies comparable to other high redshift molecular emission line
galaxies. The results are used to test the idea that star formation in these
galaxies occurs in a large number of basic units, the units being similar to
star-forming clumps in the Milky Way. The luminosity of these extreme galaxies
can be reproduced in a simple model with (0.9-30) *10^6 dense clumps, each with
a luminosity of 5 *10^5 Lsun, the mean value for such clumps in the Milky Way.
Radiative transfer models of such clumps can provide reasonable matches to the
overall SEDs of the galaxies. They indicate that the individual clumps are
quite opaque in the far-infrared. Luminosity to mass ratios vary over two
orders of magnitude, correlating strongly with the dust temperature derived
from simple fits to the SED. The gas masses derived from the dust modeling are
in remarkable agreement with those from CO luminosities, suggesting that the
assumptions going into both calculations are reasonable.Comment: 17 pages, 8 figures. Accepted by Ap
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