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We study the uniqueness and accuracy of the numerical solution of the problem of reconstruction of the shape and trajectory of a reflecting obstacle moving in an inhomogeneous medium from travel times, start and end points, and initial…

Data Structures and Algorithms · Computer Science 2014-01-17 Kamen M. Lozev

We consider an inverse problem of reconstructing a degeneracy point in the diffusion coefficient in a one-dimensional parabolic equation by measuring the normal derivative on one side of the domain boundary. We analyze the sensitivity of…

Analysis of PDEs · Mathematics 2023-11-17 Piermarco Cannarsa , Anna Doubova , Masahiro Yamamoto

Adding to our previous method for dealing with gravitational modifications at redshift $z\gtrsim3$ through a single parameter, we investigate treatment of lower redshift modifications to linear growth observables. We establish subpercent…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-29 Mikhail Denissenya , Eric V. Linder

Mathematical methods of step-by-step and combined shifts are proposed for experimental data processing to reconstruct the measuring system impulse response distorted by shift-invariant blur. Proposed methods base on direct non-blind…

Signal Processing · Electrical Eng. & Systems 2019-01-24 Andrey V. Novikov-Borodin

In this article we recover the distribution function (and possible density) of an arbitrary random variable that is subject to an additive measurement error. This problem is also known as deconvolution and has a long tradition in…

Statistics Theory · Mathematics 2025-10-07 Henrik Kaiser

We consider the inverse problem of the reconstruction of the spatially distributed dielectric constant $\varepsilon_{r}\left(\mathbf{x}\right), \ \mathbf{x}\in \mathbb{R}^{3}$, which is an unknown coefficient in the Maxwell's equations,…

Numerical Analysis · Mathematics 2015-06-19 Larisa Beilina , Nguyen Trung Thành , Michael V. Klibanov , John Bondestam Malmberg

We study the reconstructed deceleration parameter splitting the data in different redshift bins, fitting both a cosmographic luminosity distance and also assuming a flat $\Lambda$CDM model, using the Pantheon+ sample of type Ia supernova…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-20 Erick Pastén , Victor Cárdenas

In this paper, we use the Cosmokinematics approach to study the accelerated expansion of the Universe. This is a model independent approach and depends only on the assumption that the Universe is homogeneous and isotropic and is described…

General Relativity and Quantum Cosmology · Physics 2016-01-06 Nisha Rani , Deepak Jain , Shobhit Mahajan , Amitabha Mukherjee , Nilza Pires

The connection between parton distributions as a function of the impact parameter and off-forward parton distributions is discussed in the limit of vanishing skewedness parameter $\xi$, i.e. when the off-forwardness is purely transverse. It…

High Energy Physics - Phenomenology · Physics 2007-05-23 M. Burkardt

Recent research has emphasized the benefits of accurately reconstructing the initial Lagrangian positions of biased tracers from their positions at a later time, to gain cosmological information. A weighted semi-discrete optimal transport…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-10 Farnik Nikakhtar , Nikhil Padmanabhan , Bruno Lévy , Ravi K. Sheth , Roya Mohayaee

We revisit the problem of robust principal component analysis with features acting as prior side information. To this aim, a novel, elegant, non-convex optimization approach is proposed to decompose a given observation matrix into a…

Machine Learning · Statistics 2017-09-15 Niannan Xue , Jiankang Deng , Yannis Panagakis , Stefanos Zafeiriou

We propose new restarting strategies for the accelerated coordinate descent method. Our main contribution is to show that for a well chosen sequence of restarting times, the restarted method has a nearly geometric rate of convergence. A…

Optimization and Control · Mathematics 2019-10-04 Olivier Fercoq , Zheng Qu

A model-independent reconstruction of the cosmic expansion rate is essential to a robust analysis of cosmological observations. Our goal is to demonstrate that current data are able to provide reasonable constraints on the behavior of the…

Cosmology and Nongalactic Astrophysics · Physics 2012-05-17 Emille E. O. Ishida , Rafael S. de Souza

By incorporating the curvature $\Omega_k$ as a free parameter, it has been found that the tension between the high redshift CMB shift parameter $R(z^{\ast})$ data and the low redshift SNIa and BAO data from the combination of SDSS and…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Jianmang Lin , Puxun Wu , Hongwei Yu

The aim of this paper is to discuss potential advances in PET kinetic models and direct reconstruction of kinetic parameters. As a prominent example we focus on a typical task in perfusion imaging and derive a system of…

Optimization and Control · Mathematics 2014-11-20 Louise Reips , Martin Burger , Ralf Engbers

In this study we present constraints on the deceleration (q) and jerk (j) parameters using the late time integrated Sachs-Wolfe effect, type Ia supernovae, and H(z) data . We first directly measure the deceleration and jerk parameters using…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-12 Syed Faisal ur Rahman

We present a next-to-leading evaluation of the resummed coefficient function for the shape function. The results confirm our previous leading order analysis, namely that the coefficient function is short-distance-dominated, and allow…

High Energy Physics - Phenomenology · Physics 2009-11-07 U. Aglietti

We introduce the problem of reconstructing a sequence of multidimensional real vectors where some of the data are missing. This problem contains regression and mapping inversion as particular cases where the pattern of missing data is…

Machine Learning · Computer Science 2011-09-16 Miguel Á. Carreira-Perpiñán

We investigate how well the redshift distributions of galaxies sorted into photometric redshift bins can be determined from the galaxy angular two-point correlation functions. We find that the uncertainty in the reconstructed redshift…

Astrophysics · Physics 2008-11-26 M. Schneider , L. Knox , H. Zhan , A. Connolly

Distance measurements are currently the most powerful tool to study the expansion history of the universe without specifying its matter content nor any theory of gravitation. Assuming only an isotropic, homogeneous and flat universe, in…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-02 S. D. P. Vitenti , M. Penna-Lima