English
Related papers

Related papers: On Nonlinear Approximations to Cosmic Problems wit…

200 papers

We consider a moving boundary problem with kinetic condition that describes the diffusion of solvent into rubber and study semi-discrete finite element approximations of the corresponding weak solutions. We report on both a priori and a…

Numerical Analysis · Mathematics 2022-01-10 Surendra Nepal , Yosief Wondmagegne , Adrian Muntean

Weak gravitational lensing surveys are rapidly becoming important tools to probe directly the mass density fluctuations in the universe and its background dynamics. Earlier studies have shown that it is possible to model the statistics of…

Astrophysics · Physics 2009-11-07 Patrick Valageas , Andrew J. Barber , Dipak Munshi

This paper introduces a general method to approximate the convolution of an arbitrary program with a Gaussian kernel. This process has the effect of smoothing out a program. Our compiler framework models intermediate values in the program…

Graphics · Computer Science 2017-06-06 Yuting Yang , Connelly Barnes

For the purpose of maximum likelihood estimation of static parameters, we apply a kernel smoother to the particles in the standard SIR filter for non-linear state space models with additive Gaussian observation noise. This reduces the Monte…

Computation · Statistics 2015-05-07 Tore Selland Kleppe , Hans Julius Skaug

This paper studies the behavior of singularly perturbed nonlinear differential equations with boundary-layer solutions that do not necessarily converge to an equilibrium. Using the average of the fast variable and assuming the boundary…

Systems and Control · Computer Science 2018-09-24 Mohammad Deghat , Saeed Ahmadizadeh , Dragan Nesic , Chris Manzie

We provide a roadmap to establish improved lower bounds on the decay rate of the uniform radius of analyticity $\sigma(T)$ for a given nonlinear dispersive equation, reducing the problem to the derivation of nonlinear smoothing estimates…

Analysis of PDEs · Mathematics 2025-07-18 Mikaela Baldasso , Simão Correia

Semi-analytical methods, based on Eulerian perturbation theory, are a promising tool to follow the time evolution of cosmological perturbations at small redshifts and at mildly nonlinear scales. All these schemes are based on two…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Massimo Pietroni , Gianpiero Mangano , Ninetta Saviano , Matteo Viel

An effective-medium theory is proposed for random weakly nonlinear dielectric media. It is based on a new gaussian approximation for the probability distributions of the electric field in each component of a multi-phase composite. These…

Materials Science · Physics 2008-04-17 Yves-Patrick Pellegrini

Diffuse domain methods (DDMs) have garnered significant attention for approximating solutions to partial differential equations on complex geometries. These methods implicitly represent the geometry by replacing the sharp boundary interface…

Analysis of PDEs · Mathematics 2025-04-25 Toai Luong , Tadele Mengesha , Steven M. Wise , Ming Hei Wong

Nonlinear approximation methods such as the Zeldovich approximation, and more recently the frozen flow and linear potential approximations, are sometimes used to simulate nonlinear gravitational instability in the expanding Universe. We…

Astrophysics · Physics 2009-10-22 D. Munshi , A. A. Starobinsky

Current tools for multivariate density estimation struggle when the density is concentrated near a nonlinear subspace or manifold. Most approaches require choice of a kernel, with the multivariate Gaussian by far the most commonly used.…

Methodology · Statistics 2021-10-07 Minerva Mukhopadhyay , Didong Li , David B Dunson

We prove quantitative regularity estimates for the solutions to non-linear continuity equations and their discretized numerical approximations on Cartesian grids when advected by a rough force field. This allow us to recover the known…

Analysis of PDEs · Mathematics 2016-12-01 F. Ben Belgacem , P-E Jabin

We consider an aggregation model with nonlinear diffusion in domains with boundaries and investigate the zero diffusion limit of its solutions. We establish the convergence of weak solutions for fixed times, as well as the convergence of…

Analysis of PDEs · Mathematics 2018-09-05 Razvan C. Fetecau , Mitchell Kovacic , Ihsan Topaloglu

In this work we investigate the nonlinear and nonlocal relation between cosmological density and peculiar velocity fields. Our goal is to provide an algorithm for the recon- struction of the nonlinear velocity field from the fully nonlinear…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Francisco-Shu Kitaura , Raul E. Angulo , Yehuda Hoffman , Stefan Gottl"ober

This paper shows that large nonparametric classes of conditional multivariate densities can be approximated in the Kullback--Leibler distance by different specifications of finite mixtures of normal regressions in which normal means and…

Statistics Theory · Mathematics 2010-10-05 Andriy Norets

We consider density estimators based on the nearest neighbors method applied to discrete point distibutions in spaces of arbitrary dimensionality. If the density is constant, the volume of a hypersphere centered at a random location is…

Instrumentation and Methods for Astrophysics · Physics 2013-01-24 Przemek Wozniak , Andrzej Kruszewski

This letter is concerned with solving continuous-discrete Gaussian smoothing problems by using the Taylor moment expansion (TME) scheme. In the proposed smoothing method, we apply the TME method to approximate the transition density of the…

Numerical Analysis · Mathematics 2021-11-05 Zheng Zhao , Simo Särkkä

We explore the possibility of putting constraints on dark energy models with statistical property of large scale structure in the non-linear region. In particular, we investigate the $w$ dependence of non-Gaussianity of the smoothed density…

Astrophysics · Physics 2010-10-27 Takayuki Tatekawa , Shuntaro Mizuno

In several cases of nonlinear dispersive PDEs, the difference between the nonlinear and linear evolutions with the same initial data, i.e. the integral term in Duhamel's formula, exhibits improved regularity. This property is usually called…

Analysis of PDEs · Mathematics 2019-11-26 Simão Correia , Jorge Drumond Silva

The multiple-Dirichlet-to-Neumann (multiple-DtN) non-reflecting boundary condition is adapted to acoustic scattering from obstacles embedded in the half-plane. The multiple-DtN map is coupled with the method of images as an alternative…

Computational Physics · Physics 2014-01-03 Sebastian Acosta , Vianey Villamizar , Bruce Malone