检索结果-内蒙古大学图书馆

26th Annual computational Neuroscience Meeting (CNS*2017): Part 3 Antwerp, Belgium. 15-20 July 2017 Abstracts

BMC NEUROSCIENCE 2017年第SUPPL 1期18卷 95-176页

作者： [Anonymous] Department of Neuroscience Yale University New Haven CT 06520 USA Department Physiology & Pharmacology SUNY Downstate Brooklyn NY 11203 USA NYU School of Engineering 6 MetroTech Center Brooklyn NY 11201 USA Departament de Matemàtica Aplicada Universitat Politècnica de Catalunya Barcelona 08028 Spain Institut de Neurobiologie de la Méditerrannée (INMED) INSERM UMR901 Aix-Marseille Univ Marseille France Center of Neural Science New York University New York NY USA Aix-Marseille Univ INSERM INS Inst Neurosci Syst Marseille France Laboratoire de Physique Théorique et Modélisation CNRS UMR 8089 Université de Cergy-Pontoise 95300 Cergy-Pontoise Cedex France Department of Mathematics and Computer Science ENSAT Abdelmalek Essaadi’s University Tangier Morocco Laboratory of Natural Computation Department of Information and Electrical Engineering and Applied Mathematics University of Salerno 84084 Fisciano SA Italy Department of Medicine University of Salerno 84083 Lancusi SA Italy Dipartimento di Fisica Università degli Studi Aldo Moro Bari and INFN Sezione Di Bari Italy Data Analysis Department Ghent University Ghent Belgium Coma Science Group University of Liège Liège Belgium Cruces Hospital and Ikerbasque Research Center Bilbao Spain BIOtech Department of Industrial Engineering University of Trento and IRCS-PAT FBK 38010 Trento Italy Department of Data Analysis Ghent University Ghent 9000 Belgium The Wellcome Trust Centre for Neuroimaging University College London London WC1N 3BG UK Department of Electronic Engineering NED University of Engineering and Technology Karachi Pakistan Blue Brain Project École Polytechnique Fédérale de Lausanne Lausanne Switzerland Departement of Mathematics Swansea University Swansea Wales UK Laboratory for Topology and Neuroscience at the Brain Mind Institute École polytechnique fédérale de Lausanne Lausanne Switzerland Institute of Mathematics University of Aberdeen Aberdeen Scotland UK Department of Integrativ

来源：评论

学校读者我要写书评

暂无评论

Pseudo prolate spheroidal functions 11

Pseudo prolate spheroidal functions

引用

11th International Conference on Sampling Theory and Applications, SampTA 2015

作者： Daniel Abreu, Luis Pereira, Joao M. Austrian Academy of Sciences Acoustics Research Institute Wohllebengasse 12-14 ViennaA-1040 Austria Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States

ISBN: (纸本)9781467373531

Let Dt and BΩ denote the operators which cut the time content outside T and the frequency content outside Ω, respectively. The prolate spheroidal functions are the eigen-functions of the operator Ρτ,Ω = DtBΩDt. With the aim of formulating in precise mathematical terms the notion of Nyquist rate, Landau and Pollack have shown that, asymptotically, the number of such functions with eigenvalue close to one is ≈ TΩ/2π. We have recently revisited this problem with a new approach: instead of counting the number of eigenfunctions with eigenvalue close to one, we count the maximum number of orthogonal Ε-pseudoeigenfunctions with Ε-pseudoeigenvalue one. Precisely, we count how many orthogonal functions have a maximum of energy e outside the domain T x Ω, in the sense that PT, Ωf - f2 ≤ Ε. We have recently discovered that the sharp asymptotic number is ≈ (1 - Ε)-1TΩ/2π. The proof involves an explicit construction of the pseudoeigenfunctions of PT, Ω. When T and Ω are intervals we call them pseudo prolate spheroidal functions. In this paper we explain how they are constructed. © 2015 IEEE.

关键词： Orthogonal functions

来源：评论

学校读者我要写书评

暂无评论

Robust camera location estimation by convex programming

Robust camera location estimation by convex programming

引用

Conference on Computer Vision and Pattern Recognition (CVPR)

作者： Onur Özyeşil Amit Singer Program in Applied and Computational Mathematics Princeton University Princeton NJ USA Department of Mathematics Princeton University Princeton NJ USA

3D structure recovery from a collection of 2D images requires the estimation of the camera locations and orientations, i.e. the camera motion. For large, irregular collections of images, existing methods for the location estimation part, which can be formulated as the inverse problem of estimating n locations t 1 , t 2 , ..., tn in ℝ 3 from noisy measurements of a subset of the pairwise directions t i -t j /∥t i -t j ∥, are sensitive to outliers in direction measurements. In this paper, we firstly provide a complete characterization of well-posed instances of the location estimation problem, by presenting its relation to the existing theory of parallel rigidity. For robust estimation of camera locations, we introduce a two-step approach, comprised of a pairwise direction estimation method robust to outliers in point correspondences between image pairs, and a convex program to maintain robustness to outlier directions. In the presence of partially corrupted measurements, we empirically demonstrate that our convex formulation can even recover the locations exactly. Lastly, we demonstrate the utility of our formulations through experiments on Internet photo collections.

关键词： Estimation Cameras Robustness Noise measurement Three-dimensional displays Accuracy Minimization

来源：评论

学校读者我要写书评

暂无评论

FOSLL∗ for nonlinear partial differential equations

FOSLL∗ for nonlinear partial differential equations

引用

作者： Lee, Eunjung Manteuffel, Thomas A. Westphal, Chad R. Department of Computational Science and Engineering Yonsei University Seoul120-749 Korea Republic of Department of Applied Mathematics University of Colorado at Boulder BoulderCO80309 United States Department of Mathematics and Computer Science Wabash College CrawfordsvilleIN47933 United States

In previous work, the first-order system LL∗ (FOSLL∗) method was developed for linear partial differential equations. This approach seeks to minimize the residual of the equations in a dual norm induced by the differential operator, yielding approximations accurate in L2(Ω) rather than H1(Ω) or H(Div). In this paper, the general framework of FOSLL∗ is extended to a wide range of nonlinear problems. Four approaches to propagating an inexact Newton iteration based on a FOSLL∗ approximation are presented, and theory for robust convergence in L2(Ω) is established. Numerical results are presented for two formulations of the steady incompressible Navier-Stokes equations and for a diffusion equation with reduced regularity due to a discontinuous diffusion coefficient. © 2015 Society for Industrial and applied mathematics.

关键词： Newton-Raphson method

来源：评论

学校读者我要写书评

暂无评论

On solvability of a elliptic-parabolic problem of nonlinear filtration theory

引用

IOP Conference Series: Materials Science and Engineering 2016年第1期158卷

作者： M F Pavlova E V Rung Department of Computational Mathematics Institute of Computational Mathematics and Information Technologies Kazan Federal University 18 Kremlyovskaya Street Kazan 420008 Russia Department of Applied Mathematics Institute of Computational Mathematics and Information Technologies Kazan Federal University 18 Kremlyovskaya Street Kazan 420008 Russia

Existence of a strong solution of the initial-boundary value problem modeling the process of liquid filtration in an arbitrary bounded region Ω of space Rn is proven. For determining a generalized solution, the Kirchhoff transform is used, and it is assumed that the domain of the Kirchhoff function constitutes only a part of the real axis. For proving the existence theorem, the method of semidiscretization with respect to the variable t and the Galerkin method are used.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Confined disordered strictly jammed binary sphere packings

引用

Physical Review E 2015年第6期92卷 062207-062207页

作者： D. Chen S. Torquato Department of Chemistry Department of Physics Princeton Institute for the Science and Technology of Materials and Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

Disordered jammed packings under confinement have received considerably less attention than their bulk counterparts and yet arise in a variety of practical situations. In this work, we study binary sphere packings that are confined between two parallel hard planes and generalize the Torquato-Jiao (TJ) sequential linear programming algorithm [Phys. Rev. E 82, 061302 (2010)] to obtain putative maximally random jammed (MRJ) packings that are exactly isostatic with high fidelity over a large range of plane separation distances H, small to large sphere radius ratio α, and small sphere relative concentration x. We find that packing characteristics can be substantially different from their bulk analogs, which is due to what we term “confinement frustration.” Rattlers in confined packings are generally more prevalent than those in their bulk counterparts. We observe that packing fraction, rattler fraction, and degree of disorder of MRJ packings generally increase with H, though exceptions exist. Discontinuities in the packing characteristics as H varies in the vicinity of certain values of H are due to associated discontinuous transitions between different jammed states. When the plane separation distance is on the order of two large-sphere diameters or less, the packings exhibit salient two-dimensional features; when the plane separation distance exceeds about 30 large-sphere diameters, the packings approach three-dimensional bulk packings. As the size contrast increases (as α decreases), the rattler fraction dramatically increases due to what we call “size-disparity” frustration. We find that at intermediate α and when x is about 0.5 (50-50 mixture), the disorder of packings is maximized, as measured by an order metric ψ that is based on the number density fluctuations in the direction perpendicular to the hard walls. We also apply the local volume-fraction variance στ2(R) to characterize confined packings and find that these packings possess essentially the same level of

关键词： RESEARCH Combinatorial packing & covering Linear programming Density Powders Sphere packings

来源：评论

学校读者我要写书评

暂无评论

Ground states of stealthy hyperuniform potentials. II. Stacked-slider phases

引用

Physical Review E 2015年第2期92卷 022120-022120页

作者： G. Zhang F. H. Stillinger S. Torquato Department of Chemistry Department of Physics Princeton Institute for the Science and Technology of Materials and Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

Stealthy potentials, a family of long-range isotropic pair potentials, produce infinitely degenerate disordered ground states at high densities and crystalline ground states at low densities in d-dimensional Euclidean space Rd. In the previous paper in this series, we numerically studied the entropically favored ground states in the canonical ensemble in the zero-temperature limit across the first three Euclidean space dimensions. In this paper, we investigate using both numerical and theoretical techniques metastable stacked-slider phases, which are part of the ground-state manifold of stealthy potentials at densities in which crystal ground states are favored entropically. Our numerical results enable us to devise analytical models of this phase in two, three, and higher dimensions. Utilizing this model, we estimated the size of the feasible region in configuration space of the stacked-slider phase, finding it to be smaller than that of crystal structures in the infinite-system-size limit, which is consistent with our recent previous work. In two dimensions, we also determine exact expressions for the pair correlation function and structure factor of the analytical model of stacked-slider phases and analyze the connectedness of the ground-state manifold of stealthy potentials in this density regime. We demonstrate that stacked-slider phases are distinguishable states of matter; they are nonperiodic, statistically anisotropic structures that possess long-range orientational order but have zero shear modulus. We outline some possible future avenues of research to elucidate our understanding of this unusual phase of matter.

关键词： GROUND state (Quantum mechanics) ENERGY levels (Quantum mechanics) EUCLIDEAN domains MOLECULAR dynamics QUANTUM entropy

来源：评论

学校读者我要写书评

暂无评论

Fundamental physics with the square kilometre array

arXiv

引用

arXiv 2018年

作者： Weltman, A. Bull, P. Camera, S. Kelley, K. Padmanabhan, H. Pritchard, J. Racanelli, A. Riemer-Sørensen, S. Shao, L. Andrianomena, S. Athanassoula, E. Bacon, D. Barkana, R. Bertone, G. Bonvin, C. Bosma, A. Brüggen, M. Burigana, C. Bœhm, C. Calore, F. Cembranos, J.A.R. Clarkson, C. Connors, R.M.T. de la Cruz-Dombriz, Á. Dunsby, P.K.S. Fonseca, J. Fornengo, N. Gaggero, D. Harrison, I. Larena, J. Ma, Y.-Z. Maartens, R. Méndez-Isla, M. Mohanty, S.D. Murray, S.G. Parkinson, D. Pourtsidou, A. Quinn, P. Regis, M. Saha, P. Sahlén, M. Sakellariadou, M. Silk, J. Trombetti, T. Vazza, F. Venumadhav, T. Vidotto, F. Villaescusa-Navarro, F. Wang, Y. Weniger, C. Wolz, L. Zhang, F. Gaensler, B.M. Department of Mathematics & Applied Mathematics University of Cape Town 7701 Rondebosch Cape Town South Africa Department of Astronomy University of California Berkeley BerkeleyCA94720 United States Dipartimento di Fisica Università degli Studi di Torino INFN Sezione di Torino INAF – Istituto Nazionale di Astrofisica Via P. Giuria 1 Torino10125 Italy University of Western Australia Ken and Julie Michael Building 7 Fairway CrawleyWA6009 Australia ETH Zurich Wolfgang-Pauli-Strasse 27 ZurichCH 8093 Switzerland Department of Physics Imperial College London Prince Consort Road LondonSW7 2AZ United Kingdom Martí Franquès 1 BarcelonaE08028 Spain Institute of Theoretical Astrophysics University of Oslo P.O. Box 1029 Blindern OsloN-0315 Norway Kavli Institute for Astronomy and Astrophysics Peking University Beijing100871 China The Park Park Road Cape Town7405 South Africa Aix Marseille Univ CNRS CNES LAM Marseille France Institute of Cosmology & Gravitation University of Portsmouth PortsmouthPO1 3FX United Kingdom Raymond and Beverly Sackler School of Physics and Astronomy Tel Aviv University Tel Aviv69978 Israel GRAPPA Institute of Physics University of Amsterdam Science Park 904 Amsterdam1098 XH Netherlands School of Physics University of Sydney NSW Australia 2006 Australia Département de Physique Théorique Center for Astroparticle Physics Université de Genève Genève 41211 Switzerland Aix Marseille Univ CNRS CNES LAM Marseille France University of Hamburg Gojenbergsweg 112 Hamburg21029 Germany INAF Istituto di Radioastronomia Via Piero Gobetti 101 BolognaI-40129 Italy GRAPPA Institute of Physics University of Amsterdam Science Park 904 Amsterdam1098 XH Netherlands Departamento de Física Teórica I and UPARCOS Universidad Complutense de Madrid MadridE-28040 Spain School of Physics & Astronomy Queen Mary University of London LondonE1 4NS United Kingdom Cahill Center for Astronomy and Astrophysics California Instit

The Square Kilometre Array (SKA) is a planned large radio interferometer designed to operate over a wide range of frequencies, and with an order of magnitude greater sensitivity and survey speed than any current radio telescope. The SKA will address many important topics in astronomy, ranging from planet formation to distant galaxies. However, in this work, we consider the perspective of the SKA as a facility for studying physics. We review four areas in which the SKA is expected to make major contributions to our understanding of fundamental physics: cosmic dawn and reionisation;gravity and gravitational radiation;cosmology and dark energy;and dark matter and astroparticle physics. These discussions demonstrate that the SKA will be a spectacular physics machine, which will provide many new breakthroughs and novel insights on matter, energy and spacetime. Copyright © 2018, The Authors. All rights reserved.

关键词： Galaxies

来源：评论

学校读者我要写书评

暂无评论

Ground states of stealthy hyperuniform potentials: I. Entropically favored configurations

引用

Physical Review E 2015年第2期92卷 022119-022119页

Systems of particles interacting with “stealthy” pair potentials have been shown to possess infinitely degenerate disordered hyperuniform classical ground states with novel physical properties. Previous attempts to sample the infinitely degenerate ground states used energy minimization techniques, introducing algorithmic dependence that is artificial in nature. Recently, an ensemble theory of stealthy hyperuniform ground states was formulated to predict the structure and thermodynamics that was shown to be in excellent agreement with corresponding computer simulation results in the canonical ensemble (in the zero-temperature limit). In this paper, we provide details and justifications of the simulation procedure, which involves performing molecular dynamics simulations at sufficiently low temperatures and minimizing the energy of the snapshots for both the high-density disordered regime, where the theory applies, as well as lower densities. We also use numerical simulations to extend our study to the lower-density regime. We report results for the pair correlation functions, structure factors, and Voronoi cell statistics. In the high-density regime, we verify the theoretical ansatz that stealthy disordered ground states behave like “pseudo” disordered equilibrium hard-sphere systems in Fourier space. The pair statistics obey certain exact integral conditions with very high accuracy. These results show that as the density decreases from the high-density limit, the disordered ground states in the canonical ensemble are characterized by an increasing degree of short-range order and eventually the system undergoes a phase transition to crystalline ground states. In the crystalline regime (low densities), there exist aperiodic structures that are part of the ground-state manifold but yet are not entropically favored. We also provide numerical evidence suggesting that different forms of stealthy pair potentials produce the same ground-state ensemble in the zero-temperatur

关键词： THERMODYNAMIC equilibrium PROBABILITY theory QUANTUM spin models MOLECULAR dynamics QUANTUM entropy

来源：评论

学校读者我要写书评

暂无评论

New High-order Methods using Gaussian Processes for computational Fluid Dynamics Simulations

引用

Journal of Physics: Conference Series 2017年第1期837卷

作者： Dongwook Lee Adam Reyes Carlo Graziani Petros Tzeferacos Applied Mathematics and Statistics University of California Santa Cruz CA U.S.A Department of Physics University of California Santa Cruz CA U.S.A Flash Center for Computational Science Department of Astronomy & Astrophysics University of Chicago IL U.S.A Physics Oxford University U.K

We present an entirely new class of high-order numerical algorithms for computational fluid dynamics simulations. The new method is based on the Gaussian Processes (GP) modeling that generalizes the Gaussian probability distribution. Our approach is to adapt the idea of the GP prediction technique that utilizes the covariance kernel functions, and use the GP prediction to interpolate/reconstruct a high-order approximations for solving hyperbolic PDEs. We propose the GP high-order method as a new class of numerical high-order formulations, alternative to the conventional polynomial-based approaches.

关键词：

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：