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A fully analytic statistical formalism does not yet exist to describe radio-wavelength measurements of linearly polarized intensity that are produced using rotation measure synthesis. In this work we extend the analytic formalism for…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 Christopher A. Hales , Bryan M. Gaensler , Ray P. Norris , Enno Middelberg

It has already been shown that microlensing can give rise to a non-zero variable polarisation signal. Here we use realistic simulations to demonstrate the additional information that can be gained from polarimetric observations of lensing…

Astrophysics · Physics 2009-10-30 A. M. Newsam , J. F. L. Simmons , M. A. Hendry , I. J. Coleman

Using graphs to model irregular information domains is an effective approach to deal with some of the intricacies of contemporary (network) data. A key aspect is how the data, represented as graph signals, depend on the topology of the…

Signal Processing · Electrical Eng. & Systems 2023-05-02 Fernando J. Iglesias Garcia , Santiago Segarra , Antonio G. Marques

Image reconstruction in very-long baseline interferometry operates under severely sparse aperture coverage with calibration challenges from both the participating instruments and propagation medium, which introduce the risk of biases and…

Instrumentation and Methods for Astrophysics · Physics 2026-01-14 Samuel Lai , Nithyanandan Thyagarajan , O. Ivy Wong , Foivos Diakogiannis

Graphs constructed to translate some graph problem into another graph problem are usually called auxiliary graphs. Specifically total graphs of simple graphs are used to translate the total colouring problem of the original graph into a…

General Mathematics · Mathematics 2016-02-16 Ravi Goyal , Mahipal Jadeja , Rahul Muthu

In graph signal processing, one of the most important subjects is the study of filters, i.e., linear transformations that capture relations between graph signals. One of the most important families of filters is the space of shift invariant…

Signal Processing · Electrical Eng. & Systems 2022-09-29 Feng Ji , See Hian Lee , Wee Peng Tay

The effects of the polarization characteristics of beam trains in optical long-baseline interferometers are well known and have led to difficulties in measuring the spatial coherence of astronomical sources in the past. This has been…

Instrumentation and Methods for Astrophysics · Physics 2026-03-23 Guy Perrin

In this paper we consider the problem of constructing graph Fourier transforms (GFTs) for directed graphs (digraphs), with a focus on developing multiple GFT designs that can capture different types of variation over the digraph…

Signal Processing · Electrical Eng. & Systems 2023-04-11 Laura Shimabukuro , Antonio Ortega

While the polar system may lack the universal familiarity of its Cartesian counterpart, it remains indispensable for certain tasks. Summary polar diagrams, such as Taylor and mutual information diagrams, address tasks like discovering…

Human-Computer Interaction · Computer Science 2026-04-21 Aleksandar Anžel , Zewen Yang , Georges Hattab

We introduce an algorithm to solve linear inverse problems regularized with the total (gradient) variation in a gridless manner. Contrary to most existing methods, that produce an approximate solution which is piecewise constant on a fixed…

Signal Processing · Electrical Eng. & Systems 2025-07-08 Yohann de Castro , Vincent Duval , Romain Petit

We introduce and study a mathematical framework for a broad class of regularization functionals for ill-posed inverse problems: Regularization Graphs. Regularization graphs allow to construct functionals using as building blocks linear…

Optimization and Control · Mathematics 2022-09-28 Kristian Bredies , Marcello Carioni , Martin Holler

Interferometers play an increasingly important role for spatially resolved observations. If employed at full potential, interferometry can probe an enormous dynamic range in spatial scale. Interpretation of the observed visibilities…

Instrumentation and Methods for Astrophysics · Physics 2015-06-19 C. Brinch , C. P. Dullemond

We present recent improvements in polarization analysis with the INTEGRAL SPI data. The SPI detector plane consists of 19 independent Ge crystals and can operate as a polarimeter. The anisotropy characteristics of Compton diffusions can…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 M. Chauvin , J. P. Roques , D. J. Clark , E. Jourdain

We study perfect multiple coverings in translation invariant graphs with vertex set $\mathbb{Z}^2$ using an algebraic approach. In this approach we consider any such covering as a two-dimensional binary configuration which we then express…

Combinatorics · Mathematics 2023-01-13 Elias Heikkilä , Pyry Herva , Jarkko Kari

We report theoretical calculations and experimental observations of Pancharatnam's phase originating from arbitrary SU(2) transformations applied to polarization states of light. We have implemented polarimetric and interferometric methods…

Quantum Physics · Physics 2015-10-14 J. C. Loredo , O. Ortíz , R. Weingärtner , F. De Zela

In digital signal processing, shift-invariant filters can be represented as a polynomial expansion of a shift operation,that is, the Z-transform representation. When extended to graph signal processing (GSP), this would mean that a…

Signal Processing · Electrical Eng. & Systems 2018-08-15 Liyan Chen , Samuel Cheng , Vlandimir Stankovic , Lina Stankovic

Polarization-resolved control and measurement of the optical field are essential for a wide range of photonic systems, including coherent communication, polarimetric sensing, and quantum information processing. We present a photonic…

We introduce the notion of porous invariants for multipath (or branching/nondeterministic) affine loops over the integers; these invariants are not necessarily convex, and can in fact contain infinitely many 'holes'. Nevertheless, we show…

Logic in Computer Science · Computer Science 2021-06-02 Engel Lefaucheux , Joël Ouaknine , David Purser , James Worrell

We give a procedure that can be used to automatically satisfy invariants of a certain shape. These invariants may be written with the operations intersection, composition and converse over binary relations, and equality over these…

Logic in Computer Science · Computer Science 2018-06-26 Sebastiaan J. C. Joosten

We expand on our previous study of the impact of atmospheric seeing on polarization cross-talk, and show how the formalism that was developed in that work can be applied to treat the case of spatial modulators of polarization. Beside…

Instrumentation and Methods for Astrophysics · Physics 2026-02-17 Roberto Casini , Alfred G. de Wijn