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Modeling time-harmonic Maxwell problems in heterogeneous media presents significant mathematical and computational challenges. Due to the inherent non-elliptic structure and non-coercive nature of Maxwell equations, conventional methods…

数值分析 · 数学 2026-04-30 Xiang Zhong , Eric T. Chung , Xingguang Jin

A class of algorithms for the solution of discrete material optimization problems in electromagnetic applications is discussed. The idea behind the algorithm is similar to that of the sequential programming. However, in each major iteration…

最优化与控制 · 数学 2017-07-14 Johannes Semmler , Lukas Pflug , Michael Stingl

Many real-world problems in machine learning, signal processing, and communications assume that an unknown vector $x$ is measured by a matrix A, resulting in a vector $y=Ax+z$, where $z$ denotes the noise; we call this a single measurement…

信息论 · 计算机科学 2017-07-13 Junan Zhu

First-principles calculation of nonlinear magneto-optical effects has become an indispensable tool to reveal the geometric and topological nature of electronic states and to understand light-matter interactions. While intriguingly rich…

材料科学 · 物理学 2022-02-23 Haowei Chen , Meng Ye , Nianlong Zou , Bing-lin Gu , Yong Xu , Wenhui Duan

We consider the problem of reconstructing the shape of an impenetrable sound-soft obstacle from scattering measurements. The input data is assumed to be the far-field pattern generated when a plane wave impinges on an unknown obstacle from…

数值分析 · 数学 2015-05-28 Carlos Borges , Leslie Greengard

We discuss a time-harmonic inverse scattering problem for a nonlinear Helmholtz equation with compactly supported inhomogeneous scattering objects that are described by a nonlinear refractive index in unbounded free space. Assuming the…

偏微分方程分析 · 数学 2022-02-14 Roland Griesmaier , Marvin Knöller , Rainer Mandel

The area of inverse problems in mathematics is highly interdisciplinary. In various fields of science, engineering, medicine, and industry, there arises a need to reconstruct information about unknown entities that cannot be directly…

数值分析 · 数学 2024-09-17 Manabu Machida

A linear inverse problem is proposed that requires the determination of multiple unknown signal vectors. Each unknown vector passes through a different system matrix and the results are added to yield a single observation vector. Given the…

数值分析 · 计算机科学 2010-09-03 Adam C. Zelinski , Vivek K Goyal , Elfar Adalsteinsson

The inverse scattering transform is developed to solve the Maxwell-Bloch system of equations that describes two-level systems with inhomogeneous broadening, in the case of optical pulses that do not vanish at infinity in the future. The…

可精确求解与可积系统 · 物理学 2024-11-12 Asela Abeya , Gino Biondini , Gregor Kovačič , Barbara Prinari

This paper is concerned with the problem of scattering of time-harmonic electromagnetic waves from an impenetrable obstacle in a piecewise homogeneous medium. The well-posedness of the direct problem is established, employing the integral…

偏微分方程分析 · 数学 2015-05-18 Xiaodong Liu , Bo Zhang , Jiaqing Yang

The advent of novel nonlinear materials has stirred unprecedented interest in exploring the use of temporal inhomogeneities to achieve novel forms of wave control, amidst the greater vision of engineering metamaterials across both space and…

光学 · 物理学 2022-11-24 Emanuele Galiffi , Shixiong Yin , Andrea Alù

For semilinear wave equations on Lorentzian manifolds with quadratic derivative non-linear terms, we study the inverse problem of determining the background Lorentzian metric. Under some conditions on the nonlinear term, we show that from…

偏微分方程分析 · 数学 2016-12-15 Yiran Wang , Ting Zhou

This paper provides a theoretical foundation for some common formulations of inverse problems in wave propagation, based on hyperbolic systems of linear integro-differential equations with bounded and measurable coefficients. The…

数学物理 · 物理学 2015-06-12 Kirk D. Blazek , Christiaan C. Stolk , William W. Symes

We consider the time-harmonic elastic wave scattering from a general (possibly anisotropic) inhomogeneous medium with an embedded impenetrable obstacle. We show that the impenetrable obstacle can be effectively approximated by an isotropic…

偏微分方程分析 · 数学 2021-02-19 Zhengjian Bai , Huaian Diao , Hongyu Liu , Qingle Meng

In numerous practical applications, especially in medical image reconstruction, it is often infeasible to obtain a large ensemble of ground-truth/measurement pairs for supervised learning. Therefore, it is imperative to develop unsupervised…

图像与视频处理 · 电气工程与系统科学 2021-03-31 Subhadip Mukherjee , Ozan Öktem , Carola-Bibiane Schönlieb

Least squares form one of the most prominent classes of optimization problems, with numerous applications in scientific computing and data fitting. When such formulations aim at modeling complex systems, the optimization process must…

最优化与控制 · 数学 2021-05-31 E. Bergou , Y. Diouane , V. Kungurtsev , C. W. Royer

This paper is concerned with the detection of objects immersed in anisotropic media from boundary measurements. We propose an accurate approach based on the Kohn-Vogelius formulation and the topological sensitivity analysis method. The…

偏微分方程分析 · 数学 2017-07-13 Maatoug Hassine , Imen Kallel

We consider the problem of reconstructing the features of a weak anisotropic background potential by the trajectories of vortex dipoles in a nonlinear Gross-Pitaevskii equation. At leading order, the dynamics of vortex dipoles are given by…

偏微分方程分析 · 数学 2017-11-22 Ru-Yu Lai , Ravi Shankar , Daniel Spirn , Gunther Uhlmann

Detecting inhomogeneities in the electrical conductivity is a special case of the inverse problem in electrical impedance tomography, that leads to fast direct reconstruction methods. One such method can, under reasonable assumptions,…

数值分析 · 数学 2018-08-16 Henrik Garde

We investigate the inverse problem of determining nonlinear elastic material parameters from boundary stress measurements corresponding to prescribed boundary displacements. The material law is described by a nonlinear, space-independent…

偏微分方程分析 · 数学 2026-01-23 David Johansson , Yavar Kian