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Accurate estimation of the cascaded channel from a user equipment (UE) to a base station (BS) via each reconfigurable intelligent surface (RIS) element is critical to realizing the full potential of the RIS's ability to control the overall…

Signal Processing · Electrical Eng. & Systems 2024-11-08 Özlem Tuğfe Demir , Emil Björnson , Luca Sanguinetti

Component separation methods mitigate the cross-contamination between different extragalactic and galactic contributions to cosmic microwave background (CMB) data. This is often done by linearly combining CMB maps from different frequency…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-26 Jack Y. L. Kwok , William R. Coulton , Niall MacCrann , Fiona McCarthy , Boris Bolliet , Blake D. Sherwin

We are presenting an Internal Linear Combination (ILC) CMB map, in which the foreground is reduced through harmonic variance minimization. We have derived our method by converting a general form of pixel-space approach into spherical…

Astrophysics · Physics 2009-09-29 Jaiseung Kim , Pavel Naselsky , Per Rex Christensen

We propose a new internal linear combination (ILC) method in the pixel space, applicable on large angular scales of the sky, to estimate a foreground minimized Cosmic Microwave Background (CMB) temperature anisotropy map by incorporating…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-07 Vipin Sudevan , Rajib Saha

A new package for nonlinear least squares fitting is introduced in this paper. This package implements a recently developed algorithm that, for certain types of nonlinear curve fitting, reduces the number of nonlinear parameters to be…

Statistics Theory · Mathematics 2024-02-07 J. A. F. Torvisco , R. Benítez , M. R. Arias , J. Cabello Sánchez

To create high-fidelity cosmic microwave background maps, current component separation methods rely on availability of information on different foreground components, usually through multi-band frequency coverage of the instrument. Internal…

Instrumentation and Methods for Astrophysics · Physics 2023-06-02 Guillermo F. Quispe Peña , Andrei V. Frolov

The 'Internal Linear Combination' (ILC) component separation method has been extensively used to extract a single component, the CMB, from the WMAP multifrequency data. We generalise the ILC approach for separating other millimetre…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-24 Mathieu Remazeilles , Jacques Delabrouille , Jean-Francois Cardoso

The indefinite least squares (ILS) problem is a generalization of the famous linear least squares problem. It minimizes an indefinite quadratic form with respect to a signature matrix. For this problem, we first propose an impressively…

Numerical Analysis · Mathematics 2022-03-30 Yanjun Zhang , Hanyu Li

We discuss an approach to the component separation of microwave, multi-frequency sky maps as those typically produced from Cosmic Microwave Background (CMB) Anisotropy data sets. The algorithm is based on the two step, parametric,…

Astrophysics · Physics 2009-06-23 R. Stompor , S. Leach , F. Stivoli , C. Baccigalupi

We analyze a simple prefiltered variation of the least squares estimator for the problem of estimation with biased, semi-parametric noise, an error model studied more broadly in causal statistics and active learning. We prove an oracle…

Machine Learning · Computer Science 2019-02-05 Max Simchowitz , Ross Boczar , Benjamin Recht

We propose a solution to the CMB component separation problem based on standard parameter estimation techniques. We assume a parametric spectral model for each signal component, and fit the corresponding parameters pixel by pixel in a…

Based on realistic simulations, we propose an hybrid method to reconstruct the lensing potential power spectrum, directly on PLANCK-like CMB frequency maps. It implies using a large galactic mask and dealing with a strong inhomogeneous…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-20 S. Plaszczynski , A. Lavabre , L. Perotto , J. -L. Starck

Future cosmic microwave background (CMB) experiments are primarily targeting a detection of the primordial $B$-mode polarisation. The faintness of this signal requires exquisite control of systematic effects which may bias the measurements.…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-05 F. Carralot , A. Carones , N. Krachmalnicoff , T. Ghigna , A. Novelli , L. Pagano , F. Piacentini , C. Baccigalupi , D. Adak , A. Anand , J. Aumont , S. Azzoni , M. Ballardini , A. J. Banday , R. B. Barreiro , N. Bartolo , S. Basak , A. Basyrov , M. Bersanelli , M. Bortolami , T. Brinckmann , F. Cacciotti , P. Campeti , E. Carinos , F. J. Casas , K. Cheung , L. Clermont , F. Columbro , G. Conenna , G. Coppi , A. Coppolecchia , F. Cuttaia , P. de Bernardis , M. De Lucia , S. Della Torre , E. Di Giorgi , P. Diego-Palazuelos , T. Essinger-Hileman , E. Ferreira , F. Finelli , C. Franceschet , G. Galloni , M. Galloway , M. Gervasi , R. T. Génova-Santos , S. Giardiello , C. Gimeno-Amo , E. Gjerløw , A. Gruppuso , M. Hazumi , S. Henrot-Versillé , L. T. Hergt , E. Hivon , H. Ishino , B. Jost , K. Kohri , L. Lamagna , C. Leloup , M. Lembo , F. Levrier , A. I. Lonappan , M. López-Caniego , G. Luzzi , J. Macias-Perez , E. Martínez-González , S. Masi , S. Matarrese , T. Matsumura , S. Micheli , M. Monelli , L. Montier , G. Morgante , B. Mot , L. Mousset , Y. Nagano , R. Nagata , T. Namikawa , P. Natoli , I. Obata , A. Occhiuzzi , A. Paiella , D. Paoletti , G. Pascual-Cisneros , G. Patanchon , V. Pavlidou , G. Pisano , G. Polenta , L. Porcelli , G. Puglisi , N. Raffuzzi , M. Remazeilles , J. A. Rubiño-Martín , M. Ruiz-Granda , J. Sanghavi , D. Scott , M. Shiraishi , R. M. Sullivan , Y. Takase , K. Tassis , L. Terenzi , M. Tomasi , M. Tristram , L. Vacher , B. van Tent , P. Vielva , G. Weymann-Despres , E. J. Wollack , M. Zannoni , Y. Zhou

We study computational aspects of a key problem in robust statistics -- the penalized least trimmed squares (LTS) regression problem, a robust estimator that mitigates the influence of outliers in data by capping residuals with large…

Optimization and Control · Mathematics 2026-04-15 Xiang Meng , Andrés Gómez , Rahul Mazumder

The problem of fitting experimental data to a given model function $f(t; p_1,p_2,\dots,p_N)$ is conventionally solved numerically by methods such as that of Levenberg-Marquardt, which are based on approximating the Chi-squared measure of…

Optimization and Control · Mathematics 2017-03-14 Alberto Herrera-Gomez , R. Michael Porter

This paper presents a new approach to solve linear and nonlinear model predictive control (MPC) problems that requires small memory footprint and throughput and is particularly suitable when the model and/or controller parameters change at…

Optimization and Control · Mathematics 2021-03-25 Nilay Saraf , Alberto Bemporad

Data analysis and interpretation often relies on an approximation of an empirical dataset by some analytic functions or models. Actual implementations usually rely on a non-linear multi-dimensional optimization algorithm, typically…

Instrumentation and Methods for Astrophysics · Physics 2025-01-29 Igor Chilingarian , Kirill Grishin

Many applications of generalised linear models (GLMs) can be improved by applying constraints that impose assumptions on the associations or improve consistency of the estimators. Yet, there are still barriers to the implementation and…

Methodology · Statistics 2026-02-19 Pierre Masselot , Devon Nenon , Jacopo Vanoli , Zaid Chalabi , Antonio Gasparrini

Calibrating mathematical models of biological processes is essential for achieving predictive accuracy and gaining mechanistic insight. However, this task remains challenging due to limited and noisy data, significant biological…

Quantitative Methods · Quantitative Biology 2025-12-04 Piotr Gwiazda , Alexey Kazarnikov , Anna Marciniak-Czochra , Zuzanna Szymańska

The internal linear combination (ILC) method is a popular approach for constructing component-separated maps in cosmic microwave background (CMB) analyses. It optimally combines observed maps at different frequencies to produce an unbiased…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-05 Kristen M. Surrao , J. Colin Hill