9,804 research outputs found
A note on a solution of three body problem
Equilateral triangle solution of three-body problem for Apollo Earth-Moon libration point mission
Evolution of Surface Deformations of Weakly-Bound Nuclei in the Continuum
We study weakly-bound deformed nuclei based on the coordinate-space Skyrme
Hartree-Fock-Bogoliubov approach, in which a large box is employed for treating
the continuum and surface diffuseness. Approaching the limit of core-halo
deformation decoupling, calculations found an exotic "egg"-like structure
consisting of a spherical core plus a prolate halo in Ne, in which the
resonant continuum plays an essential role. Generally the halo probability and
the decoupling effect in heavy nuclei are reduced compared to light nuclei, due
to denser level densities around Fermi surfaces. However, deformed halos in
medium-mass nuclei are possible with sparse levels of negative parity, for
example, in Ge. The surface deformations of pairing density
distributions are also influenced by the decoupling effect and are sensitive to
the effective pairing Hamiltonian.Comment: 5 pages and 5 figure
Aligning Manifolds of Double Pendulum Dynamics Under the Influence of Noise
This study presents the results of a series of simulation experiments that
evaluate and compare four different manifold alignment methods under the
influence of noise. The data was created by simulating the dynamics of two
slightly different double pendulums in three-dimensional space. The method of
semi-supervised feature-level manifold alignment using global distance resulted
in the most convincing visualisations. However, the semi-supervised
feature-level local alignment methods resulted in smaller alignment errors.
These local alignment methods were also more robust to noise and faster than
the other methods.Comment: The final version will appear in ICONIP 2018. A DOI identifier to the
final version will be added to the preprint, as soon as it is availabl
Small-scale CMB Temperature and Polarization Anisotropies due to Patchy Reionization
We study contributions from inhomogeneous (patchy) reionization to arcminute
scale () cosmic microwave background (CMB) anisotropies.
We show that inhomogeneities in the ionization fraction, rather than in the
mean density, dominate both the temperature and the polarization power spectra.
Depending on the ionization history and the clustering bias of the ionizing
sources, we find that rms temperature fluctuations range from 2 K to 8
K and the corresponding values for polarization are over two orders of
magnitude smaller. Reionization can significantly bias cosmological parameter
estimates and degrade gravitational lensing potential reconstruction from
temperature maps but not from polarization maps. We demonstrate that a simple
modeling of the reionization temperature power spectrum may be sufficient to
remove the parameter bias. The high- temperature power spectrum will
contain some limited information about the sources of reionization.Comment: 11 pages, 8 figures. Minor changes to match version accepted by Ap
Overall Evolution of Realistic Gamma-ray Burst Remnant and Its Afterglow
Conventional dynamic model of gamma-ray burst remnants is found to be
incorrect for adiabatic blastwaves during the non-relativistic phase. A new
model is derived, which is shown to be correct for both radiative and adiabatic
blastwaves during both ultra-relativistic and non-relativistic phase. Our model
also takes the evolution of the radiative efficiency into account. The
importance of the transition from the ultra-relativistic phase to the
non-relativistic phase is stressed.Comment: 9 pages, aasms4 style, 3 ps figures, minor changes, will be published
in Chin. Phys. Let
Emergent Soft Monopole Modes in Weakly-Bound Deformed Nuclei
Based on the Hartree-Fock-Bogoliubov solutions in large deformed coordinate
spaces, the finite amplitude method for quasiparticle random phase
approximation (FAM-QRPA) has been implemented, providing a suitable approach to
probe collective excitations of weakly-bound nuclei embedded in the continuum.
The monopole excitation modes in Magnesium isotopes up to the neutron drip line
have been studied with the FAM-QRPA framework on both the coordinate-space and
harmonic oscillator basis methods. Enhanced soft monopole strengths and
collectivity as a result of weak-binding effects have been unambiguously
demonstrated.Comment: 5 pages, 4 figures, accepted for PRC (Rapid Comm.
A unified approach to combinatorial key predistribution schemes for sensor networks
There have been numerous recent proposals for key predistribution schemes for wireless sensor networks based on various types of combinatorial structures such as designs and codes. Many of these schemes have very similar properties and are analysed in a similar manner. We seek to provide a unified framework to study these kinds of schemes. To do so, we define a new, general class of designs, termed âpartially balanced t-designsâ, that is sufficiently general that it encompasses almost all of the designs that have been proposed for combinatorial key predistribution schemes. However, this new class of designs still has sufficient structure that we are able to derive general formulas for the metrics of the resulting key predistribution schemes. These metrics can be evaluated for a particular scheme simply by substituting appropriate parameters of the underlying combinatorial structure into our general formulas. We also compare various classes of schemes based on different designs, and point out that some existing proposed schemes are in fact identical, even though their descriptions may seem different. We believe that our general framework should facilitate the analysis of proposals for combinatorial key predistribution schemes and their comparison with existing schemes, and also allow researchers to easily evaluate which scheme or schemes present the best combination of performance metrics for a given application scenario
Exact Histogram Specification Optimized for Structural Similarity
An exact histogram specification (EHS) method modifies its input image to
have a specified histogram. Applications of EHS include image (contrast)
enhancement (e.g., by histogram equalization) and histogram watermarking.
Performing EHS on an image, however, reduces its visual quality. Starting from
the output of a generic EHS method, we maximize the structural similarity index
(SSIM) between the original image (before EHS) and the result of EHS
iteratively. Essential in this process is the computationally simple and
accurate formula we derive for SSIM gradient. As it is based on gradient
ascent, the proposed EHS always converges. Experimental results confirm that
while obtaining the histogram exactly as specified, the proposed method
invariably outperforms the existing methods in terms of visual quality of the
result. The computational complexity of the proposed method is shown to be of
the same order as that of the existing methods.
Index terms: histogram modification, histogram equalization, optimization for
perceptual visual quality, structural similarity gradient ascent, histogram
watermarking, contrast enhancement
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