66,210 research outputs found
The effect of lift on the wave-making resistance of multi-hull craft
A potential based panel method is presented to estimate the wave-making characteristics of multi-hull craft. In order to simulate the lifting potential flow around the sub-hulls, the method adopts mixed source/doublet distributions on the sub-hulls and their wake surface, while sources are distributed on the main hull and the free surface. In this way, the asymmetric flow characteristics of the sub-hull are properly simulated, i.e., a Kutta condition is satisfied at the trailing edge of the sub-hull. Comparison is made between the numerical and model experimental measurements, and a good correlation has been found. The wave-making characteristics and pressure distributions on the sub-hull predicted by the present method can differ from those based on a distribution of sources alone, especially the pressure distributions at the stern of the sub-hulls
The effect of temperature evolution on the interior structure of HO-rich planets
For most planets in the range of radii from 1 to 4 R, water is a
major component of the interior composition. At high pressure HO can be
solid, but for larger planets, like Neptune, the temperature can be too high
for this. Mass and age play a role in determining the transition between solid
and fluid (and mixed) water-rich super-Earth. We use the latest high-pressure
and ultra-high-pressure phase diagrams of HO, and by comparing them
with the interior adiabats of various planet models, the temperature evolution
of the planet interior is shown, especially for the state of HO. It
turns out that the bulk of HO in a planet's interior may exist in
various states such as plasma, superionic, ionic, Ice VII, Ice X, etc.,
depending on the size, age and cooling rate of the planet. Different regions of
the mass-radius phase space are also identified to correspond to different
planet structures. In general, super-Earth-size planets (isolated or without
significant parent star irradiation effects) older than about 3 Gyr would be
mostly solid.Comment: Accepted by ApJ, in print for March 2014 (14 pages, 3 colored
figures, 1 table
Optimal Control of Brucellosis in Bison in the Yellowstone National Park Area
Brucellosis is a highly infectious bacterial disease that causes infected females to abort their calves. It has caused devastating losses to U.S. farmers over the last century. The only known focus of Brucellosis left in the nation is wildlife such as bison and elk in the Greater Yellowstone Area. Vaccination and test-and-slaughter have been applied to brucellosis management in bison, and there has been discussion that a combination of both could potentially eradicate the disease in the Yellowstone National Park. However, there is no study on how to allocate resources between the two actions. This paper investigates the optimal allocation of these two selective management options, in a bioeconomic framework, when there are both existence and recreational values for the wildlife host (bison) and when the host puts the livestock sector at risk.Bioeconomics, brucellosis, disease ecology, epidemiology, optimal control, susceptible-infected-recovered (SIR) model, Resource /Energy Economics and Policy,
A seakeeping analysis method for an air-lifted vessel
A seakeeping analysis in the frequency domain is presented to predict the motion response of an airlifted vessel (ALV) in waves. The ALV is supported by pressurised air in two separate cushion chambers; the pressure variation in the cushions has a significant effect on the motions of the vessel. The adiabatic gas law is used to couple cushion pressure and the free-surface elevation of water inside the chamber. Attention is focused on the waves generated by the pressure, and a method is presented to compute the corresponding free-surface elevation. New numerical schemes are proposed for calculating the threedimensional free-surface elevation for the four wave numbers. Numerical results of the free-surface elevation, escape area, escape volume and motion responses of the ALV are provided. & 2008 Elsevier Ltd. All rights reserved
Adversarial Deep Structured Nets for Mass Segmentation from Mammograms
Mass segmentation provides effective morphological features which are
important for mass diagnosis. In this work, we propose a novel end-to-end
network for mammographic mass segmentation which employs a fully convolutional
network (FCN) to model a potential function, followed by a CRF to perform
structured learning. Because the mass distribution varies greatly with pixel
position, the FCN is combined with a position priori. Further, we employ
adversarial training to eliminate over-fitting due to the small sizes of
mammogram datasets. Multi-scale FCN is employed to improve the segmentation
performance. Experimental results on two public datasets, INbreast and
DDSM-BCRP, demonstrate that our end-to-end network achieves better performance
than state-of-the-art approaches.
\footnote{https://github.com/wentaozhu/adversarial-deep-structural-networks.git}Comment: Accepted by ISBI2018. arXiv admin note: substantial text overlap with
arXiv:1612.0597
Coupled-resonator-induced transparency with a squeezed vacuum
We present the first experimental observation of quantum fluctuation spectra
in two coupled optical cavities with an injected squeezed vacuum light. The
quadrature components of the reflected squeezed vacuum spectra are measured by
phase sensitive homodyne detector. The experimental results demonstrate
coupled-resonator-induced transparency in the quantum regime, in which
electromagnetically-induced-transparency-like characteristic of the absorption
and dispersion properties of the coupled optical cavities determines the
line-shape of the reflected quantum noise spectra.Comment: 4 pages, 4 figures, appear in Phys. Rev. Let
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