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We make some computations in stable motivic homotopy theory over Spec \mathbb{C}, completed at 2. Using homotopy fixed points and the algebraic K-theory spectrum, we construct a motivic analogue of the real K-theory spectrum KO. We also…

Algebraic Topology · Mathematics 2010-02-12 Daniel C. Isaksen , Armira Shkembi

The K2 mission is a repurposed use of the Kepler spacecraft to perform high-precision photometry of selected fields in the ecliptic. We have developed an aperture photometry pipeline for K2 data which performs dynamic automated aperture…

Instrumentation and Methods for Astrophysics · Physics 2015-12-01 Derek L. Buzasi , Lindsey Carboneau , Carly Hessler , Andy Lezcano , Heather Preston

We investigate the statistical recovery of missing physics and turbulent phenomena in fluid flows using generative machine learning. Here we develop a two-stage super-resolution method using spectral filtering to restore the high-wavenumber…

The frequency distribution of different parameters of an EXAFS spectrum can be directly sampled by analysing a population of simulated spectra produced by adding computer-generated noise to a reference pattern. The procedure gives…

Data Analysis, Statistics and Probability · Physics 2007-05-23 Paolo Ghigna , Melissa di Muri , Giorgio Spinolo

We present a novel RG approach to 2D random XY models using direct and replicated Coulomb gas methods. By including fusion of environments (charge fusion in the replicated CG) it follows the distribution of local disorder, found to obey a…

Condensed Matter · Physics 2009-10-31 David Carpentier , Pierre Le Doussal

We present a new method for time-efficient and accurate extraction of the power spectrum from future cosmic microwave background (CMB) maps based on properties of peaks and troughs of the Gaussian CMB sky. We construct a statistic…

Astrophysics · Physics 2009-11-06 A. Kashlinsky , C. Hernández--Monteagudo , F. Atrio--Barandela

Here we present new joint reconstruction and regularization techniques inspired by ideas in microlocal analysis and lambda tomography, for the simultaneous reconstruction of the attenuation coefficient and electron density from X-ray…

Image and Video Processing · Electrical Eng. & Systems 2020-08-26 James Webber , Eric Todd Quinto , Eric L. Miller

In this work we present cosmological N-body simulations of the Local Universe with initial conditions constrained by the Two-Micron Redshift Survey (2MRS) within a cubic volume of 180 Mpc/h side-length centred at the Local Group. We use a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Steffen Heß , Francisco-Shu Kitaura , Stefan Gottloeber

Unsupervised machine learning methods are used to identify structural changes using the melting point transition in classical molecular dynamics simulations as an example application of the approach. Dimensionality reduction and clustering…

Computational Physics · Physics 2018-12-06 Nicholas Walker , Ka-Ming Tam , Brian Novak , M. Jarrell

Data-driven emulators are increasingly being used to learn and emulate physics-based simulations, reducing computational expense and run time. Here, we present a structured way to improve the quality of these high-dimensional emulated…

Machine Learning · Computer Science 2025-04-25 Nawid Keshtmand , Elena Fillola , Jeffrey Nicholas Clark , Raul Santos-Rodriguez , Matthew Rigby

We introduce an alternative method for the calculation of sky maps from data taken with gamma-ray telescopes. In contrast to the established method of smoothing the 2D histogram of reconstructed event directions with a static kernel, we…

High Energy Astrophysical Phenomena · Physics 2024-01-30 M. Holler , T. Mitterdorfer , S. Panny

Meta-learning involves training models on a variety of training tasks in a way that enables them to generalize well on new, unseen test tasks. In this work, we consider meta-learning within the framework of high-dimensional multivariate…

Statistics Theory · Mathematics 2024-04-01 Yanhao Jin , Krishnakumar Balasubramanian , Debashis Paul

Pursuing the original idea proposed in our previous paper (Paper I), we improve the method to determine the shape of the initial curvature perturbation spectrum $P(k)$ from the CMB data. The thickness of the last scattering surface (LSS)…

Astrophysics · Physics 2009-10-09 Makoto Matsumiya , Misao Sasaki , Jun'ichi Yokoyama

We study the problem of spectrum estimation from transmission data of a known phantom. The goal is to reconstruct an x-ray spectrum that can accurately model the x-ray transmission curves and reflects a realistic shape of the typical energy…

Medical Physics · Physics 2021-07-14 Wooseok Ha , Emil Y. Sidky , Rina Foygel Barber , Taly Gilat Schmidt , Xiaochuan Pan

Next-generation accelerator concepts which hinge on the precise shaping of beam distributions, demand equally precise diagnostic methods capable of reconstructing beam distributions within 6-dimensional position-momentum spaces. However,…

We study the problem of estimating a manifold from random samples. In particular, we consider piecewise constant and piecewise linear estimators induced by k-means and k-flats, and analyze their performance. We extend previous results for…

Machine Learning · Computer Science 2015-03-20 Guillermo D. Canas , Tomaso Poggio , Lorenzo Rosasco

We develop a statistically robust framework for reconstructing metal--semiconductor contact regions using topological gradients. The inverse problem is formulated as the identification of an unknown contact region from boundary measurements…

Numerical Analysis · Mathematics 2026-03-05 Lekbir Afraites , Aissam Hadri , Mourad Hrizi , Julius Fergy Tiongson Rabago

The pseudospectral method, in conjunction with a new technique for obtaining scaling exponents $\zeta_n$ from the structure functions $S_n(r)$, is presented as an alternative to the extended self-similarity (ESS) method and the use of…

Fluid Dynamics · Physics 2014-11-25 W. D. McComb , S. R. Yoffe , M. F. Linkmann , A. Berera

We explore the sensitivity of several core-level spectroscopic methods to the underlying atomistic structure by using the water molecule as our test system. We first define a metric that measures the magnitude of spectral change as a…

Chemical Physics · Physics 2022-06-22 Johannes Niskanen , Anton Vladyka , Joonas Niemi , Christoph J. Sahle

We use semiclassical methods to evaluate the spectral two-point correlation function of quantum chaotic systems with discrete geometrical symmetries. The energy spectra of these systems can be divided into subspectra that are associated to…

Chaotic Dynamics · Physics 2013-02-12 Chris Joyner , Sebastian Müller , Martin Sieber