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We consider the Bayesian approach to the inverse problem of recovering the shape of an object from measurements of its scattered acoustic field. Working in the time-harmonic setting, we focus on a Helmholtz transmission problem and then…

Analysis of PDEs · Mathematics 2024-10-31 Safiere Kuijpers , Laura Scarabosio

The curved spacetime induced by gravitational waves can give rise to visual effects such as geometric distortions and redshift structures in the observed image. By establishing a mapping from the object's surface coordinates to the…

General Relativity and Quantum Cosmology · Physics 2024-04-12 Ke Wang , Chao-Jun Feng

The reconstruction problem of voxels with individual weightings can be modeled a position- and angle- dependent function in the forward-projection. This changes the system matrix and prohibits to use standard filtered backprojection. In…

Computer Vision and Pattern Recognition · Computer Science 2020-10-28 Lina Felsner , Tobias Würfl , Christopher Syben , Philipp Roser , Alexander Preuhs , Andreas Maier , Christian Riess

Gravitational waves in isotropic cosmologies were recently studied using the gauge-invariant approach of Ellis-Bruni. We now construct the linearised metric perturbations of the background Robertson-Walker space-time which reproduce the…

General Relativity and Quantum Cosmology · Physics 2009-11-10 E. M. O'Shea

In this article we introduce an approach for studying the geodesic X-ray transform and related geometric inverse problems by using Carleman estimates. The main result states that on compact negatively curved manifolds (resp. nonpositively…

Analysis of PDEs · Mathematics 2021-11-29 Gabriel P. Paternain , Mikko Salo

For a certain class of configurations of points in space, Eves' Theorem gives a ratio of products of distances that is invariant under projective transformations, generalizing the cross-ratio for four points on a line. We give a…

Metric Geometry · Mathematics 2012-04-10 Adam Coffman

This paper is concerned with the reconstruction of the shape of an acoustic obstacle. Based on the use of the tapered waves with very narrow widths illuminating the obstacle, the boundary of the obstacle is reconstructed by a direct imaging…

Numerical Analysis · Mathematics 2024-10-10 Deyue Zhang , Mengjiao Bai , Yan Chang , Yukun Guo

A projective rectangle is like a projective plane that has different lengths in two directions. We develop the basic theory of projective rectangles including incidence properties, projective subplanes, configuration counts, a partial…

Combinatorics · Mathematics 2024-07-17 Rigoberto Florez , Thomas Zaslavsky

Clusters of wave-scattering oscillators offer the ability to passively control wave energy in elastic continua. However, designing such clusters to achieve a desired wave energy pattern is a highly nontrivial task. While the forward…

Signal Processing · Electrical Eng. & Systems 2024-02-29 Joshua R. Tempelman , Tobias Weidemann , Eric B. Flynn , Kathryn H. Matlack , Alexander F. Vakakis

As a by-product of our work on super Pl\"{u}cker embedding, we came to the notion of a weighted projective superspace $P_{+1,-1}(V\oplus W)$ with weights $+1,-1$. The construction is not in itself super and makes sense in ordinary (purely…

Differential Geometry · Mathematics 2024-02-20 Ekaterina Shemyakova , Theodore Voronov

This paper investigates the inverse biharmonic scattering problems of identifying the shape and location of the obstacle with phased and phaseless measurement data. A direct imaging method based on reverse time migration is proposed for…

Analysis of PDEs · Mathematics 2026-05-12 Tielei Zhu , Zhihao Ge

Matter wave interferometry is becoming an increasingly important technique in quantum metrology. However, unlike its photonic counterpart, this technique relies on the interference of particles possessing a non-zero rest mass and an…

We extend the geometric study of the Wasserstein space W(X) of a simply connected, negatively curved metric space X by investigating which pairs of boundary points can be linked by a geodesic, when X is a tree.

Differential Geometry · Mathematics 2013-05-14 Jérôme Bertrand , Benoit Kloeckner

This work gives an expository account of certain applications of microlocal analysis in three geometric inverse problems. We will discuss the geodesic X-ray transform inverse problem, the Gelfand problem for the wave equation on a…

Analysis of PDEs · Mathematics 2023-12-14 Mikko Salo

Seismic waves are the most sensitive probe of the Earth's interior we have. With the dense data sets available in exploration, images of subsurface structures can be obtained through processes such as migration. Unfortunately, relating…

Geophysics · Physics 2009-05-05 R. B. Schlottmann

Extending the `metric spaces' of Lawvere, we study `real metrics', with values in the extended real line. Formally, this ordered set is a symmetric monoidal closed category, and our structures are enriched categories on the latter.…

Algebraic Topology · Mathematics 2026-05-14 Marco Grandis

In this paper, we give probabilistic interpretations of both, the forward and the inverse problem of electrical impedance tomography with possibly anisotropic, merely measurable conductivities: Using the theory of symmetric Dirichlet…

Analysis of PDEs · Mathematics 2014-03-17 Petteri Piiroinen , Martin Simon

We consider an inverse spectral theory in a domain with the cavity that is bounded by a penetrable inhomogeneous medium. An ODE system is constructed piecewise through the solutions inside and outside the cavity. The ODE system is connected…

Analysis of PDEs · Mathematics 2016-05-18 Lung-Hui Chen

The inverse problem of X-tray transforms considers reconstructing functions from some data that are easier to measure, which is typically the integral of that function along geodesics. We prove that if the domain has a foliation structure,…

Analysis of PDEs · Mathematics 2024-12-11 Qiuye Jia

In this paper we study the inverse problem of determining the residual stress in Man's model using tomographic data. Theoretically, the tomographic data is obtained at zero approximation of geometrical optics for Man's residual stress…

Analysis of PDEs · Mathematics 2015-05-30 Vladimir Sharafutdinov , Jenn-Nan Wang