7,260 research outputs found
Image Restoration Using Very Deep Convolutional Encoder-Decoder Networks with Symmetric Skip Connections
In this paper, we propose a very deep fully convolutional encoding-decoding
framework for image restoration such as denoising and super-resolution. The
network is composed of multiple layers of convolution and de-convolution
operators, learning end-to-end mappings from corrupted images to the original
ones. The convolutional layers act as the feature extractor, which capture the
abstraction of image contents while eliminating noises/corruptions.
De-convolutional layers are then used to recover the image details. We propose
to symmetrically link convolutional and de-convolutional layers with skip-layer
connections, with which the training converges much faster and attains a
higher-quality local optimum. First, The skip connections allow the signal to
be back-propagated to bottom layers directly, and thus tackles the problem of
gradient vanishing, making training deep networks easier and achieving
restoration performance gains consequently. Second, these skip connections pass
image details from convolutional layers to de-convolutional layers, which is
beneficial in recovering the original image. Significantly, with the large
capacity, we can handle different levels of noises using a single model.
Experimental results show that our network achieves better performance than all
previously reported state-of-the-art methods.Comment: Accepted to Proc. Advances in Neural Information Processing Systems
(NIPS'16). Content of the final version may be slightly different. Extended
version is available at http://arxiv.org/abs/1606.0892
Neutron Density Distributions of Neutron-Rich Nuclei Studied with the Isobaric Yield Ratio Difference
The isobaric yield ratio difference (IBD) between two reactions of similar
experimental setups is found to be sensitive to nuclear density differences
between projectiles. In this article, the IBD probe is used to study the
density variation in neutron-rich Ca. By adjusting diffuseness in the
neutron density distribution, three different neutron density distributions of
Ca are obtained. The yields of fragments in the 80 MeV Ca
+ C reactions are calculated by using a modified statistical
abrasion-ablation model. It is found that the IBD results obtained from the
prefragments are sensitive to the density distribution of the projectile, while
the IBD results from the final fragments are less sensitive to the density
distribution of the projectile.Comment: 3 figure
Quasi-Rip: A New Type of Rip Model without Cosmic Doomsday
The fate of our universe is an unceasing topic of cosmology and the human
being. The discovery of the current accelerated expansion of the universe
significantly changed our view of the fate of the universe. Recently, some
interesting scenarios concerning the fate of the universe attracted much
attention in the community, namely the so-called "Little Rip" and "Pseudo-Rip".
It is worth noting that all the Big Rip, Little Rip and Pseudo-Rip arise from
the assumption that the dark energy density is monotonically
increasing. In the present work, we are interested to investigate what will
happen if this assumption is broken, and then propose a so-called "Quasi-Rip"
scenario, which is driven by a type of quintom dark energy. In this work, we
consider an explicit model of Quasi-Rip in detail. We show that Quasi-Rip has
an unique feature different from Big Rip, Little Rip and Pseudo-Rip. Our
universe has a chance to be rebuilt from the ashes after the terrible rip. This
might be the last hope in the "hopeless" rip.Comment: 9 pages, 2 figures, 1 table, revtex4; v2: discussions added, Phys.
Rev. D in press; v3: published versio
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