13,118 research outputs found
Distinguishing Computer-generated Graphics from Natural Images Based on Sensor Pattern Noise and Deep Learning
Computer-generated graphics (CGs) are images generated by computer software.
The~rapid development of computer graphics technologies has made it easier to
generate photorealistic computer graphics, and these graphics are quite
difficult to distinguish from natural images (NIs) with the naked eye. In this
paper, we propose a method based on sensor pattern noise (SPN) and deep
learning to distinguish CGs from NIs. Before being fed into our convolutional
neural network (CNN)-based model, these images---CGs and NIs---are clipped into
image patches. Furthermore, three high-pass filters (HPFs) are used to remove
low-frequency signals, which represent the image content. These filters are
also used to reveal the residual signal as well as SPN introduced by the
digital camera device. Different from the traditional methods of distinguishing
CGs from NIs, the proposed method utilizes a five-layer CNN to classify the
input image patches. Based on the classification results of the image patches,
we deploy a majority vote scheme to obtain the classification results for the
full-size images. The~experiments have demonstrated that (1) the proposed
method with three HPFs can achieve better results than that with only one HPF
or no HPF and that (2) the proposed method with three HPFs achieves 100\%
accuracy, although the NIs undergo a JPEG compression with a quality factor of
75.Comment: This paper has been published by Sensors. doi:10.3390/s18041296;
Sensors 2018, 18(4), 129
Topolgical Charged Black Holes in Generalized Horava-Lifshitz Gravity
As a candidate of quantum gravity in ultrahigh energy, the
-dimensional Ho\v{r}ava-Lifshitz (HL) gravity with critical exponent
, indicates anisotropy between time and space at short distance. In the
paper, we investigate the most general Ho\v{r}ava-Lifshitz gravity in
arbitrary spatial dimension , with a generic dynamical Ricci flow parameter
and a detailed balance violation parameter . In arbitrary
dimensional generalized HL gravity with at long distance, we
study the topological neutral black hole solutions with general in
HL, as well as the topological charged black holes with
in HL. The HL gravity in the Lagrangian formulation
is adopted, while in the Hamiltonian formulation, it reduces to DiracDe
Witt's canonical gravity with . In particular, the topological
charged black holes in HL, HL, HL and
HL with are solved. Their asymptotical behaviors near the
infinite boundary and near the horizon are explored respectively. We also study
the behavior of the topological black holes in the -dimensional HL
gravity with gauge field in the zero temperature limit and finite
temperature limit, respectively. Thermodynamics of the topological charged
black holes with , including temperature, entropy, heat capacity,
and free energy are evaluated.Comment: 51 pages, published version. The theoretical framework of z=d HL
gravity is set up, and higher curvature terms in spatial dimension become
relevant at UV fixed point. Lovelock term, conformal term, new massive term,
and Chern-Simons term with different critical exponent z are studie
Elastic metamaterials with simultaneously negative effective shear modulus and mass density
We propose a type of elastic metamaterial comprising fluid-solid composite
inclusions which can possess negative shear modulus and negative mass density
over a large frequency region. Such a solid metamaterial has a unique elastic
property that only transverse waves can propagate with a negative dispersion
while longitudinal waves are forbidden. This leads to many interesting
phenomena such as negative refraction, which is demonstrated by using a wedge
sample, and a significant amount of mode conversion from transverse waves to
longitudinal waves that cannot occur on the interface of two natural solids
Infall and outflow detections in a massive core JCMT 18354-0649S
We present a high-resolution study of a massive dense core JCMT 18354-0649S
with the Submillimeter Array. The core is mapped with continuum emission at 1.3
mm, and molecular lines including CHOH (-) and HCN (3-2).
The dust core detected in the compact configuration has a mass of and a diameter of 2\arcsec (0.06 pc), which is further resolved
into three condensations with a total mass of under higher
spatial resolution. The HCN (3-2) line exhibits asymmetric profile consistent
with infall signature. The infall rate is estimated to be yr. The high velocity HCN (3-2) line wings present an
outflow with three lobes. Their total mass is and total momentum
is km s, respectively. Analysis shows that the
N-bearing molecules especially HCN can trace both inflow and outflow.Comment: 21 pages, 7 figure
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