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Consider the electromagnetic scattering of a time-harmonic plane wave by an open cavity which is embedded in a perfectly electrically conducting infinite ground plane. This paper is concerned with the numerical solutions of the transverse…

Numerical Analysis · Mathematics 2021-04-07 Yanli Chen , Peijun Li , Xiaokai Yuan

As part of our development of a computer code to perform 3D `constrained evolution' of Einstein's equations in 3+1 form, we discuss issues regarding the efficient solution of elliptic equations on domains containing holes (i.e., excised…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Scott H. Hawley , Richard A. Matzner

We introduce a Cascaded Diffusion Model (Cas-DM) that improves a Denoising Diffusion Probabilistic Model (DDPM) by effectively incorporating additional metric functions in training. Metric functions such as the LPIPS loss have been proven…

Computer Vision and Pattern Recognition · Computer Science 2024-01-05 Jie An , Zhengyuan Yang , Jianfeng Wang , Linjie Li , Zicheng Liu , Lijuan Wang , Jiebo Luo

Latent diffusion models have become the popular choice for scaling up diffusion models for high resolution image synthesis. Compared to pixel-space models that are trained end-to-end, latent models are perceived to be more efficient and to…

Computer Vision and Pattern Recognition · Computer Science 2025-03-25 Emiel Hoogeboom , Thomas Mensink , Jonathan Heek , Kay Lamerigts , Ruiqi Gao , Tim Salimans

In this study, we prove results on the weak solvability and homogenization of a microscopic semi-linear elliptic system posed in perforated media. The model presented here explores the interplay between stationary diffusion and both surface…

Analysis of PDEs · Mathematics 2016-03-15 Vo Anh Khoa , Adrian Muntean

We present an efficient algorithm for the least squares parameter fitting optimized for component separation in multi-frequency CMB experiments. We sidestep some of the problems associated with non-linear optimization by taking advantage of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-26 Rishi Khatri

We develop a lumped parameter model to describe and predict the mass release of (absorption from) an arbitrary shaped body of any dimension in a large environment. Through the one-to-one analogy between diffusion-dominated mass transfer…

Applied Physics · Physics 2022-02-10 Pawel Rochowski , Giuseppe Pontrelli

We introduce a model description of femtosecond laser induced desorption at surfaces. The substrate part of the system is taken into account as a (possibly semi-infinite) linear chain. Here, being especially interested in the early stages…

Mesoscale and Nanoscale Physics · Physics 2016-05-25 Emil Boström , Anders Mikkelsen , Claudio Verdozzi

In this paper, we propose a $W$-cycle $p$-multigrid method for solving the $p$-version symmetric interior penalty discontinuous Galerkin (SIPDG) discretization of elliptic problems. This SIPDG discretization employs hierarchical Legendre…

Numerical Analysis · Mathematics 2025-09-18 Nuo Lei , Donghang Zhang , Weiying Zheng

Multi-target tracking is an important problem in civilian and military applications. This paper investigates multi-target tracking in distributed sensor networks. Data association, which arises particularly in multi-object scenarios, can be…

Multiagent Systems · Computer Science 2018-12-04 Mark R. Leonard , Abdelhak M. Zoubir

In the current paper the so-called REaction-DIffusion Manifold (REDIM) method of model reduction is discussed within the framework of standard singular perturbation theory. According to the REDIM a reduced model for the system describing a…

Numerical Analysis · Mathematics 2017-01-31 V. Bykov , Y. Cherkinsky , V. Gol'dshtein , N. Krapivnik , U. Maas

This article presents an error analysis of the symmetric linear/bilinear partially penalized immersed finite element (PPIFE) methods for interface problems of Helmholtz equations. Under the assumption that the exact solution possesses a…

Numerical Analysis · Mathematics 2020-06-22 Ruchi Guo , Tao Lin , Yanping Lin , Qiao Zhuang

In this paper we study the inverse problem of identifying the diffusion matrix in an elliptic PDE from measurements. The convex energy functional method with Tikhonov regularization is applied to tackle this problem. For the discretization…

Numerical Analysis · Mathematics 2017-09-15 Michael Hinze , Tran Nhan Tam Quyen

A computational model study for complete frequency redistribution linear incoherent two-level atomic radiation trapping in optically dense media using the multiple scattering representation is presented. This model study discuss at length…

Physics Education · Physics 2009-11-13 A. R. Alves-Pereira , E. J. Nunes-Pereira , J. M. G. Martinho , M. N. Berberan-Santos

Positron and electron cosmic rays provide a complementary way to study the galactic environment. The actual cosmic rays experiments, for instance PAMELA and HEAT, have presented very exciting results in this field. The observed positron…

Astrophysics · Physics 2009-02-04 Roberto A. Lineros

Exciton diffusion length plays a vital role in the function of opto-electronic devices. Oftentimes, the domain occupied by an organic semiconductor is subject to surface measurement error. In many experiments, photoluminescence over the…

Numerical Analysis · Mathematics 2017-12-15 Jingrun Chen , Ling Lin , Zhiwen Zhang , Xiang Zhou

We introduce a new algorithm, Construction of dIfferentially Private Empirical Distributions from a low-order marginals set tHrough solving linear Equations with l2 Regularization (CIPHER), that produces differentially private empirical…

Machine Learning · Computer Science 2021-01-08 Evercita C. Eugenio , Fang Liu

The aim of this work is to identify the mechanisms responsible for very large rates and other peculiarities observed in low-energy positron annihilation on molecules. The two mechanisms considered are: (i) Direct annihilation of the…

Atomic Physics · Physics 2009-10-31 G. F. Gribakin

Translational diffusion coefficients are routinely estimated from molecular dynamics simulations. Linear fits to mean squared displacement (MSD) curves have become the de facto standard, from simple liquids to complex biomacromolecules.…

Computational Physics · Physics 2020-11-20 Jakob Tómas Bullerjahn , Sören von Bülow , Gerhard Hummer

We propose an adaptive multigrid preconditioning technology for solving linear systems arising from Discontinuous Petrov-Galerkin (DPG) discretizations. Unlike standard multigrid techniques, this preconditioner involves only trace spaces…

Numerical Analysis · Mathematics 2020-10-15 Socratis Petrides , Leszek Demkowicz