73,914 research outputs found

    The inviscid limit of Navier-Stokes for analytic data on the half-space

    Full text link
    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 R2\mathbb{R}^2

    Full text link
    We establish the inviscid limit of the incompressible Navier-Stokes equations on the whole plane R2\mathbb{R}^2 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

    Full text link
    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

    Full text link
    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 A4A_4 symmetry model

    Full text link
    We will investigate numerically a seesaw model with A4A_4 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 O(102)\mathcal{O}(10^{-2}) eV. The effective neutrino mass m|\langle m\rangle| associated with neutrinoless double beta decay is in the range of [0.002  eV,0.038  eV][0.002 \;\mathrm{eV},0.038\;\mathrm{eV}] and [0.048  eV,0.058  eV][0.048\;\mathrm{eV},0.058\;\mathrm{eV}] 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 (ηB\eta_B) 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 M0M_0 is ranging from O(108)\mathcal{O}(10^8) GeV to O(1012)\mathcal{O}(10^{12}) GeV for tanβ=3\tan\beta =3. This allowed M0M_0 range distinguishes with the scale of O(1013)\mathcal{O}(10^{13}) GeV concerned by other effects that also generate the consistent ηB\eta_B from leptogenesis. The branching ratio of the decay μeγ \mu \rightarrow\,e\gamma may reach the future experimental sensitivity in the very light values of M0M_0. Hence, it will be inconsistent with the M0M_0 range predicted from the ηB\eta_B data whenever this decay is detected experimentally.Comment: The accepted version to PTE

    Decay of standard model-like Higgs boson hμτh\rightarrow \mu\tau in a 3-3-1 model with inverse seesaw neutrino masses

    Full text link
    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 h10μτ,eτh^0_1\rightarrow \mu\tau,e\tau, 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 h10μτ,eτh^0_1\rightarrow\mu\tau,e\tau can reach values of 10510^{-5} in the regions of parameter space satisfying the current experimental data of the decay μeγ\mu\rightarrow e\gamma. The value of 10410^{-4} 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

    Full text link
    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 C\mathcal{C} 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 C\mathcal{C} . We also construct a coordinate map on C\mathcal{C} that can be used for integration or other purposes. This topological characterization of C% \mathcal{C} 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

    Full text link
    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

    Full text link
    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

    Full text link
    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
    corecore