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We describe a simple but efficient method for deriving a consistent set of monopole and dipole corrections for multi-frequency sky map data sets, allowing robust parametric component separation with the same data set. The computational core…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-01 I. K. Wehus , U. Fuskeland , H. K. Eriksen , A. J. Banday , C. Dickinson , T Ghosh , K. M. Gorski , C. R. Lawrence , J. P. Leahy , D. Maino , P. Reich , W. Reich

We aim to reconstruct the latent space dynamics of high dimensional, quasi-stationary systems using model order reduction via the spectral proper orthogonal decomposition (SPOD). The proposed method is based on three fundamental steps: in…

Numerical Analysis · Mathematics 2022-08-17 Andrea Lario , Romit Maulik , Oliver T. Schmidt , Gianluigi Rozza , Gianmarco Mengaldo

This article looks at the combined constraints from a photometric and spectroscopic survey. These surveys will measure cosmology using weak lensing (WL), galaxy clustering, baryon acoustic oscillations (BAO) and redshift space distortions…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-22 Martin Eriksen , Enrique Gaztanaga

Tilting planar samples for multi-zone-axes observation is a routine procedure in electron microscopy. However, this process invariably introduces optical path differences in the electron beam across different sample positions, significantly…

Materials Science · Physics 2024-08-22 Jizhe Cui , Yi Zheng , Kang Sun , Wenfeng Yang , Haozhi Sha , Rong Yu

A lighting-based multispectral imaging system using an RGB camera and a projector is one of the most practical and low-cost systems to acquire multispectral observations for estimating the scene's spectral reflectance information. However,…

Image and Video Processing · Electrical Eng. & Systems 2020-12-21 Hironori Hidaka , Yusuke Monno , Masatoshi Okutomi

In this paper, a novel two-dimensional super-resolution angle-of-departure (AoD) and angle-of-arrival (AoA) estimation technique is proposed for wideband millimeter-wave multiple-input multiple-output systems with cross-polarized antenna…

Information Theory · Computer Science 2017-02-09 Dalin Zhu , Junil Choi , Robert W. Heath

This paper introduces a multifidelity formulation that reduces the computational cost of the proper orthogonal decomposition (POD) of a high-fidelity model by leveraging data from cheaper, lower-fidelity models. POD is a prevalent technique…

Numerical Analysis · Mathematics 2026-05-29 Nicole Aretz , Karen Willcox

Stochastic gradient descent (SGD) is a cornerstone of machine learning. When the number N of data items is large, SGD relies on constructing an unbiased estimator of the gradient of the empirical risk using a small subset of the original…

Machine Learning · Statistics 2021-12-14 Remi Bardenet , Subhro Ghosh , Meixia Lin

This paper describes a very efficient algorithm for image signal extrapolation. It can be used for various applications in image and video communication, e.g. the concealment of data corrupted by transmission errors or prediction in video…

Image and Video Processing · Electrical Eng. & Systems 2022-07-21 Jürgen Seiler , Katrin Meisinger , André Kaup

The use of spectral proper orthogonal decomposition (SPOD) to construct low-order models for broadband turbulent flows is explored. The choice of SPOD modes as basis vectors is motivated by their optimality and space-time coherence…

Fluid Dynamics · Physics 2021-09-22 Tianyi Chu , Oliver T. Schmidt

We discuss vertex patch smoothers as overlapping domain decomposition methods for fourth order elliptic partial differential equations. We show that they are numerically very efficient and yield high convergence rates. Furthermore, we…

Numerical Analysis · Mathematics 2025-06-23 Julius Witte , Cu Cui , Francesca Bonizzoni , Guido Kanschat

In the era of the Big Data revolution, methods for the automatic discovery of regularities in large datasets are becoming essential tools in applied sciences. This article presents an open software package, named MODULO (MODal mULtiscale…

Data Analysis, Statistics and Probability · Physics 2020-11-12 Davide Ninni , Miguel A. Mendez

The past decade and a half has seen the design and execution of several ground-based spectroscopic surveys, both Galactic and Extra-galactic. Additionally, new surveys are being designed that extend the boundaries of current surveys. In…

Instrumentation and Methods for Astrophysics · Physics 2016-06-15 G. R. Ruchti , S. Feltzing , K. Lind , E. Caffau , A. J. Korn , O. Schnurr , C. J. Hansen , A. Koch , L. Sbordone , R. S. de Jong

In this paper, we consider the model reduction problem of large-scale systems, such as systems obtained through the discretization of partial differential equations. We propose a computationally optimal randomized proper orthogonal…

Dynamical Systems · Mathematics 2016-05-04 Dan Yu , Suman Chakravorty

We describe a new algorithm for the "perfect" extraction of one-dimensional spectra from two-dimensional (2D) digital images of optical fiber spectrographs, based on accurate 2D forward modeling of the raw pixel data. The algorithm is…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 Adam S. Bolton , David J. Schlegel

This paper proposes a novel maximum Doppler spread estimation algorithm for OFDM systems with the comb-type pilot pattern. By tracking the drifting delay subspace of the multipath channel, the time correlation function is measured at a high…

Information Theory · Computer Science 2008-11-05 Xiaochuan Zhao , Tao Peng , Ming Yang , Wenbo Wang

The multi-object spectrograph (MOS) has been the benchmark for the current generation of astronomical spectrographs, valued for its ability to acquire the spectra of hundreds of objects simultaneously. In the last two decades, the digital…

Instrumentation and Methods for Astrophysics · Physics 2022-10-03 Shaojie Chen , Matthew C. H. Leung , Xuefeng Yao , Suresh Sivanandam , Isabelle Sanders , Rosalind Liang

We formulate and demonstrate experimentally the high-resolution spectral method based on Bloch-wave symmetry properties for extracting mode dispersion in periodic waveguides from measurements of near-field profiles. We characterize both the…

Diffusing wave spectroscopy (DWS) can be employed as an optical rheology tool with numerous applications for studying the structure, dynamics and linear viscoelastic properties of complex fluids, foams, glasses and gels. To carry out DWS…

Soft Condensed Matter · Physics 2018-11-06 Chi Zhang , Mathias Reufer , Danila Gaudino , Frank Scheffold

The multipath radio channel is considered to have a non-bandlimited channel impulse response. Therefore, it is challenging to achieve high resolution time-delay (TD) estimation of multipath components (MPCs) from bandlimited observations of…

Signal Processing · Electrical Eng. & Systems 2019-12-11 Tarik Kazaz , Gerard J. M. Janssen , Alle-Jan van der Veen