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A class of random non-stationary signals termed timbre x dynamics is introduced and studied. These signals are obtained by non-linear transformations of sta-tionary random gaussian signals, in such a way that the transformation can be…

Information Theory · Computer Science 2015-10-29 H Omer , B Torrésani

We present a sparse Gauss-Newton solver for accelerated sensitivity analysis with applications to a wide range of equilibrium-constrained optimization problems. Dense Gauss-Newton solvers have shown promising convergence rates for inverse…

Optimization and Control · Mathematics 2021-07-12 Jonas Zehnder , Stelian Coros , Bernhard Thomaszewski

Quantifying uncertainty in predictive simulations for real-world problems is of paramount importance - and far from trivial, mainly due to the large number of stochastic parameters and significant computational requirements. Adaptive sparse…

Computational Physics · Physics 2019-11-25 Ionut-Gabriel Farcas , Tobias Görler , Hans-Joachim Bungartz , Frank Jenko , Tobias Neckel

Discrimination between non-stationarity and long-range dependency is a difficult and long-standing issue in modelling financial time series. This paper uses an adaptive spectral technique which jointly models the non-stationarity and…

Statistical Finance · Quantitative Finance 2019-02-12 Nick James , Roman Marchant , Richard Gerlach , Sally Cripps

This paper investigates Gaussian Markov random field approximations to nonstationary Gaussian fields using graph representations of stochastic partial differential equations. We establish approximation error guarantees building on the…

Methodology · Statistics 2021-04-28 Daniel Sanz-Alonso , Ruiyi Yang

We propose RSFT, which is an extension of the one dimensional Sparse Fourier Transform algorithm to higher dimensions in a way that it can be applied to real, noisy data. The RSFT allows for off-grid frequencies. Furthermore, by…

Systems and Control · Computer Science 2016-10-05 Shaogang Wang , Vishal M. Patel , Athina Petropulu

We investigate Gabor frames on locally compact abelian groups with time-frequency shifts along non-separable, closed subgroups of the phase space. Density theorems in Gabor analysis state necessary conditions for a Gabor system to be a…

Functional Analysis · Mathematics 2015-04-22 Mads Sielemann Jakobsen , Jakob Lemvig

Retinal prostheses restore vision by electrically stimulating surviving neurons, but calibrating perceptual thresholds (i.e., the minimum stimulus intensity required for perception) remains a time-intensive challenge, especially for…

Quantitative Methods · Quantitative Biology 2025-04-30 Roksana Sadeghi , Michael Beyeler

We consider the estimation of an i.i.d. (possibly non-Gaussian) vector $\xbf \in \R^n$ from measurements $\ybf \in \R^m$ obtained by a general cascade model consisting of a known linear transform followed by a probabilistic componentwise…

Information Theory · Computer Science 2012-12-04 Ulugbek S. Kamilov , Sundeep Rangan , Alyson K. Fletcher , Michael Unser

This paper introduces Gabor scattering, a feature extractor based on Gabor frames and Mallat's scattering transform. By using a simple signal model for audio signals specific properties of Gabor scattering are studied. It is shown that for…

Sound · Computer Science 2019-10-02 Roswitha Bammer , Monika Dörfler , Pavol Harar

Time-series analysis is critical for a diversity of applications in science and engineering. By leveraging the strengths of modern gradient descent algorithms, the Fourier transform, multi-resolution analysis, and Bayesian spectral…

Signal Processing · Electrical Eng. & Systems 2021-06-23 Daniel E. Shea , Rajiv Giridharagopal , David S. Ginger , Steven L. Brunton , J. Nathan Kutz

We introduce the concept of stationary graviton non-Gaussianity (nG), an observable that can be probed in terms of 3-point correlation functions of a stochastic gravitational wave (GW) background. When evaluated in momentum space,…

General Relativity and Quantum Cosmology · Physics 2020-01-15 Cari Powell , Gianmassimo Tasinato

Neighborhood selection is a widely used method used for estimating the support set of sparse precision matrices, which helps determine the conditional dependence structure in undirected graphical models. However, reporting only point…

Methodology · Statistics 2023-12-29 Yiling Huang , Snigdha Panigrahi , Walter Dempsey

The data analysis of space-based gravitational wave detectors like Taiji faces significant challenges from non-stationary noise, which compromises the efficacy of traditional frequency-domain analysis. This work proposes a unified framework…

General Relativity and Quantum Cosmology · Physics 2025-06-23 Minghui Du , Ziren Luo , Peng Xu

We establish a general form of explicit, input-dependent, measure-valued warpings for learning nonstationary kernels. While stationary kernels are ubiquitous and simple to use, they struggle to adapt to functions that vary in smoothness…

Machine Learning · Computer Science 2020-10-12 Anthony Tompkins , Rafael Oliveira , Fabio Ramos

In this study, we develop an asymptotic theory of nonparametric regression for a locally stationary functional time series. First, we introduce the notion of a locally stationary functional time series (LSFTS) that takes values in a…

Statistics Theory · Mathematics 2022-07-04 Daisuke Kurisu

Image signals typically are defined on a rectangular two-dimensional grid. However, there exist scenarios where this is not fulfilled and where the image information only is available for a non-regular subset of pixel position. For…

Image and Video Processing · Electrical Eng. & Systems 2022-07-15 Jürgen Seiler , André Kaup

The paper considers so-called adaptive estimations of regression, distribution density and spectral density of a Gaussian stationary sequence, asymptotically optimal in order at a growing number of observation on any regular subspace…

Probability · Mathematics 2007-05-23 Eugene Ostrovsky , Leonid Sirota

A distributed adaptive algorithm for estimation of sparse unknown parameters in the presence of nonGaussian noise is proposed in this paper based on normalized least mean fourth (NLMF) criterion. At the first step, local adaptive NLMF…

Information Theory · Computer Science 2015-12-09 Mojtaba Hajiabadi

Diffusion approximation provides weak approximation for stochastic gradient descent algorithms in a finite time horizon. In this paper, we introduce new tools motivated by the backward error analysis of numerical stochastic differential…

Machine Learning · Computer Science 2019-09-05 Yuanyuan Feng , Tingran Gao , Lei Li , Jian-Guo Liu , Yulong Lu
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