46,041 research outputs found
3D Textured Model Encryption via 3D Lu Chaotic Mapping
In the coming Virtual/Augmented Reality (VR/AR) era, 3D contents will be
popularized just as images and videos today. The security and privacy of these
3D contents should be taken into consideration. 3D contents contain surface
models and solid models. The surface models include point clouds, meshes and
textured models. Previous work mainly focus on encryption of solid models,
point clouds and meshes. This work focuses on the most complicated 3D textured
model. We propose a 3D Lu chaotic mapping based encryption method of 3D
textured model. We encrypt the vertexes, the polygons and the textures of 3D
models separately using the 3D Lu chaotic mapping. Then the encrypted vertices,
edges and texture maps are composited together to form the final encrypted 3D
textured model. The experimental results reveal that our method can encrypt and
decrypt 3D textured models correctly. In addition, our method can resistant
several attacks such as brute-force attack and statistic attack.Comment: 13 pages, 7 figures, under review of SCI
Plasmonic angular momentum on metal-dielectric nano-wedges in a sectorial indefinite metamaterial
We present an analytical study to the structure-modulated plasmonic angular
momentum trapped on periodic metal-dielectric nano-wedges in the core region of
a sectorial indefinite metamaterial. Employing a transfer-matrix calculation
and a conformal-mapping technique, our theory is capable of dealing with
realistic configurations of arbitrary sector numbers and rounded wedge tips. We
demonstrate that in the deep-subwavelength regime strong electric field
carrying high azimuthal variation can exist within only ten-nanometer length
scale close to the structural center, and is naturally bounded by a
characteristic radius of the order of hundred-nanometer away from the center.
These extreme confining properties suggest that the structure under
investigation may be superior to the conventional metal-dielectric waveguides
or cavities in terms of nanoscale photonic manipulation.Comment: 16 pages, 9 figure
Conformal or Walking? Monte Carlo renormalization group studies of SU(3) gauge models with fundamental fermions
Strongly coupled gauge systems with many fermions are important in many
phenomenological models. I use the 2-lattice matching Monte Carlo
renormalization group method to study the fixed point structure and critical
indexes of SU(3) gauge models with 8 and 12 flavors of fundamental fermions.
With an improved renormalization group block transformation I am able to
connect the perturbative and confining regimes of the N_f=8 flavor system, thus
verifying its QCD-like nature. With N_f=12 flavors the data favor the existence
of an infrared fixed point and conformal phase, though the results are also
consistent with very slow walking. I measure the anomalous mass dimension in
both systems at several gauge couplings and find that they are barely different
from the free field value.Comment: 26 pages, 11 figure
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Impacts of model calibration on high-latitude land-surface processes: PILPS 2(e) calibration/validation experiments
In the PILPS 2(e) experiment, the Snow Atmosphere Soil Transfer (SAST) land-surface scheme developed from the Biosphere-Atmosphere Transfer Scheme (BATS) showed difficulty in accurately simulating the patterns and quantities of runoff resulting from heavy snowmelt in the high-latitude Torne-Kalix River basin (shared by Sweden and Finland). This difficulty exposes the model deficiency in runoff formations. After representing subsurface runoff and calibrating the parameters, the accuracy of hydrograph prediction improved substantially. However, even with the accurate precipitation and runoff, the predicted soil moisture and its variation were highly "model-dependent". Knowledge obtained from the experiment is discussed. © 2003 Elsevier Science B.V. All rights reserved
Thermodynamics of lattice QCD with 2 flavours of colour-sextet quarks: A model of walking/conformal Technicolor
QCD with two flavours of massless colour-sextet quarks is considered as a
model for conformal/walking Technicolor. If this theory possess an infrared
fixed point, as indicated by 2-loop perturbation theory, it is a
conformal(unparticle) field theory. If, on the other hand, a chiral condensate
forms on the weak-coupling side of this would-be fixed point, the theory
remains confining. The only difference between such a theory and regular QCD is
that there is a range of momentum scales over which the coupling constant runs
very slowly (walks). In this first analysis, we simulate the lattice version of
QCD with two flavours of staggered quarks at finite temperatures on lattices of
temporal extent and 6. The deconfinement and chiral-symmetry
restoration couplings give us a measure of the scales associated with
confinement and chiral-symmetry breaking. We find that, in contrast to what is
seen with fundamental quarks, these transition couplings are very different.
for each of these transitions increases significantly from
and as expected for the finite temperature transitions of an
asymptotically-free theory. This suggests a walking rather than a conformal
behaviour, in contrast to what is observed with Wilson quarks. In contrast to
what is found for fundamental quarks, the deconfined phase exhibits states in
which the Polyakov loop is oriented in the directions of all three cube roots
of unity. At very weak coupling the states with complex Polyakov loops undergo
a transition to a state with a real, negative Polyakov loop.Comment: 21 pages, 9 figures, Revtex with postscript figures. One extra
reference was added; text is unchanged. Corrected typographical erro
Nucleon Sigma Term and In-medium Quark Condensate in the Modified Quark-Meson Coupling Model
We evaluate the nucleon sigma term and in-medium quark condensate in the
modified quark-meson coupling model which features a density-dependent bag
constant. We obtain a nucleon sigma term consistent with its empirical value,
which requires a significant reduction of the bag constant in the nuclear
medium similar to those found in the previous works. The resulting in-medium
quark condensate at low densities agrees well with the model independent linear
order result. At higher densities, the magnitude of the in-medium quark
condensate tends to increase, indicating no tendency toward chiral symmetry
restoration.Comment: 9 pages, modified version to be publishe
Comments on lattice gauge theories with infrared-attractive fixed points
Theories of interacting gauge fields and fermions can possess a running gauge
coupling with an infrared attractive fixed point (IRFP). We present a minimal
description of the physics of these systems and comment on some simple
expectations for results from lattice simulations done within the basin of
attraction of the IRFP in these theories.Comment: 10 pages, 2 figures. Published version, fixed typos in version
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