73,914 research outputs found
The inviscid limit of Navier-Stokes for analytic data on the half-space
In their classical work Caflisch and Sammartino proved the inviscid limit of
the incompressible Navier-Stokes equations for well-prepared data with analytic
regularity in the half-space. Their proof is based on the detailed construction
of Prandtl's boundary layer asymptotic expansions. In this paper, we give a
direct proof of the inviscid limit for general analytic data without having to
construct Prandtl's boundary layer correctors. Our analysis makes use of the
boundary vorticity formulation and the abstract Cauchy-Kovalevskaya theorem on
analytic boundary layer function spaces that capture unbounded vorticity.Comment: to appear on Archive for Rational Mechanics and Analysi
The inviscid limit of Navier-Stokes equations for vortex-wave data on
We establish the inviscid limit of the incompressible Navier-Stokes equations
on the whole plane for initial data having vorticity as a
superposition of point vortices and a regular component. In particular, this
rigorously justifies the vortex-wave system from the physical Navier-Stokes
flows in the vanishing viscosity limit, a model that was introduced by
Marchioro and Pulvirenti in the early 90s to describe the dynamics of point
vortices in a regular ambient vorticity background. The proof rests on the
previous analysis of Gallay in his derivation of the vortex-point system.Comment: 27 page
Dephasing due to a fluctuating fractional quantum Hall edge current
The dephasing rate of an electron level in a quantum dot, placed next to a
fluctuating edge current in the fractional quantum Hall effect, is considered.
Using perturbation theory, we first show that this rate has an anomalous
dependence on the bias voltage applied to the neighboring quantum point
contact, because of the Luttinger liquid physics which describes the fractional
Hall fluid. Next, we describe exactly the weak to strong backscattering
crossover using the Bethe-Ansatz solution.Comment: Proceedings of the 6th Rencontres du Vietnam (2006
Implementation of a Geographic Information System (GIS) on the Yayasan Sabah concession: Preliminary study
The present report is the result of 6 months study realized for the first phase of preliminary assessment of the "Forestry GIS project". The project is a collaboration between Innoprise Corporation and CIRAD-forêt for the implementation of a Geographic Information System on the Yayasan Sabah concession. The study concentrates first on a "preliminary assessment prior to the GIS implementation". Three main areas of activities should be covered by the GIS : Primary forest, Secondary forest and Plantation. ICSB needs more particularly a system to gather and display up-to-date information, and to produce maps easily and quickly. A need of demonstration has also been raised. According to the forest activities of the concession and the needs, 8 main objectives are proposed: 1 Demo to present the concession and its activities, 2 Demo on a Reduce Impact Logging project, 3 Concession progress consultation, 4 Road network management, 5 Preparation of coupe in Primary forest , 6 Logged-over forest management, 7 Plantation management, 8 Support to research The description of the data available and their quality allow to foresee the possible technical difficulties of implementation. The GIS should be organized from a main system based in the headquarter of Innoprise and monitored by an independent GIS team. Two other modules, more or less independent from the main system, could be developed later according to the equipment available: an Executive Information System to be handled by senior management for the purpose of demonstration and fast progress consultation, and a localized GIS for local management such as for Rattan plantation in Luasong. For a first step of implementation, a solution with 2 PC 486 has been proposed. However, upgrading the system to workstation is desirable for a GIS on the whole concession. Moreover, satellite imagery should be a very interesting source of data for the system and must be envisaged later. Two pilot areas have been chosen to start the project on small scale: The Luasong project area and The Ulu Segama Forest Reserve. In the chapter "detailed information for the pilot project", the study proposes 6 objectives with expected outputs and gives the detail of the necessary data to be captured. Finally, the study proposes a planning of implementation for the pilot project that should be achieved quickly, between 6 months to 1 year
CP violations in a predictive symmetry model
We will investigate numerically a seesaw model with flavor symmetry to
find allowed regions satisfying the current experimental neutrino oscillation
data, then use them to predict physical consequences. Namely, the lightest
active neutrino mass has order of eV. The effective
neutrino mass associated with neutrinoless double beta
decay is in the range of and
corresponding to the normal and the
inverted hierarchy schemes. Other relations among relevant physical quantities
are shown, so that they can be determined if some of them are confirmed
experimentally. The recent data of the baryon asymmetry of the Universe
() can be explained via leptogenesis caused by the effect of the
renormalization group evolution on the Dirac Yukawa couplings, provided the
right handed neutrino mass scale is ranging from GeV
to GeV for . This allowed range
distinguishes with the scale of GeV concerned by other
effects that also generate the consistent from leptogenesis. The
branching ratio of the decay may reach the future
experimental sensitivity in the very light values of . Hence, it will be
inconsistent with the range predicted from the data whenever
this decay is detected experimentally.Comment: The accepted version to PTE
Decay of standard model-like Higgs boson in a 3-3-1 model with inverse seesaw neutrino masses
By adding new gauge singlets of neutral leptons, the improved versions of the
3-3-1 models with right-handed neutrinos have been recently introduced in order
to explain recent experimental neutrino oscillation data through the inverse
seesaw mechanism. We prove that these models predict promising signals of
lepton-flavor-violating decays of the standard-model-like Higgs boson
, which are suppressed in the original
versions. One-loop contributions to these decay amplitudes are introduced in
the unitary gauge. Based on a numerical investigation, we find that the
branching ratios of the decays can reach values
of in the regions of parameter space satisfying the current
experimental data of the decay . The value of
appears when the Yukawa couplings of leptons are close to the perturbative
limit. Some interesting properties of these regions of parameter space are also
discussed.Comment: 31 pages, 5 figures. Version accepted for publication in PR
Topology of quantum discord
Quantum discord is an important measure of quantum correlations that can
serve as a resource for certain types of quantum information processing. \ Like
entanglement, discord is subject to destruction by external noise. The routes
by which this destruction can take place depends on the shape of the
hypersurface of zero discord in the space of generalized Bloch
vectors. For 2 qubits, we show that with a few points subtracted, this
hypersurface is a simply-connected 9-dimensional manifold embedded in a
15-dimensional background space. \ We do this by constructing an explicit\
homeomorphism from a known manifold to the subtracted version of . We also construct a coordinate map on that can be used for
integration or other purposes. This topological characterization of has important implications for the classification of the possible
time evolutions of discord in physical models. The classification for discord
contrasts sharply with the possible evolutions of entanglement.
Using topological methods, we classify the possible joint evolutions of
entanglement and discord. There are 9 allowed categories: 6 categories for a
Markovian process and 3 categories for a non-Markovian process, respectively.
We illustrate these conclusions with an anisotropic XY spin model. All 9
categories can be obtained by adjusting parameters.Comment: Revised version submitted to Physical Review
Correlation Induced Enhancement of Frictional Drag between Two Dilute Two-Dimensional Layers
We comment on the huge enhancement of Coulomb drag in double layers two
dimensional hole system observed in the experiment by Pillarisetty R., et al,
PRL 86 (2002) 016805.Comment: Paper withdrawn pending major revision
A CNN-LSTM Architecture for Detection of Intracranial Hemorrhage on CT scans
We propose a novel method that combines a convolutional neural network (CNN)
with a long short-term memory (LSTM) mechanism for accurate prediction of
intracranial hemorrhage on computed tomography (CT) scans. The CNN plays the
role of a slice-wise feature extractor while the LSTM is responsible for
linking the features across slices. The whole architecture is trained
end-to-end with input being an RGB-like image formed by stacking 3 different
viewing windows of a single slice. We validate the method on the recent RSNA
Intracranial Hemorrhage Detection challenge and on the CQ500 dataset. For the
RSNA challenge, our best single model achieves a weighted log loss of 0.0522 on
the leaderboard, which is comparable to the top 3% performances, almost all of
which make use of ensemble learning. Importantly, our method generalizes very
well: the model trained on the RSNA dataset significantly outperforms the 2D
model, which does not take into account the relationship between slices, on
CQ500. Our codes and models is publicly avaiable at
https://github.com/VinBDI-MedicalImagingTeam/midl2020-cnnlstm-ich
A Spatial-temporal 3D Human Pose Reconstruction Framework
3D human pose reconstruction from single-view camera is a difficult and
challenging topic. Many approaches have been proposed, but almost focusing on
frame-by-frame independently while inter-frames are highly correlated in a pose
sequence. In contrast, we introduce a novel spatial-temporal 3D reconstruction
framework that leverages both intra and inter frame relationships in
consecutive 2D pose sequences. Orthogonal Matching Pursuit (OMP) algorithm,
pre-trained Pose-angle Limits and Temporal Models have been implemented. We
quantitatively compare our framework versus recent works on CMU motion capture
dataset and Vietnamese traditional dance sequences. Our method outperforms
others with 10 percent lower of Euclidean reconstruction error and robustness
against Gaussian noise. Additionally, it is also important to mention that our
reconstructed 3D pose sequences are smoother and more natural than others.Comment: 10 pages. JIPS Journal 201
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