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Neural time-series analysis has traditionally focused on modeling data in the time domain, often with some approaches incorporating equivalent Fourier domain representations as auxiliary spectral features. In this work, we shift the main…

Machine Learning · Computer Science 2024-10-08 Minjung Kim , Yusuke Hioka , Michael Witbrock

In nature, signals often appear in the form of the superposition of multiple non-stationary signals. The overlap of signal components in the time-frequency domain poses a significant challenge for signal analysis. One approach to addressing…

Signal Processing · Electrical Eng. & Systems 2025-10-14 Shuixin Li , Jiecheng Chen , Qingtang Jiang , Jian Lu

Partial observations of continuous time-series dynamics at arbitrary time stamps exist in many disciplines. Fitting this type of data using statistical models with continuous dynamics is not only promising at an intuitive level but also has…

Machine Learning · Computer Science 2021-10-29 Ruizhi Deng , Marcus A. Brubaker , Greg Mori , Andreas M. Lehrmann

We derive a local-time path-integral representation for a generic one-dimensional time-independent system. In particular, we show how to rephrase the matrix elements of the Bloch density matrix as a path integral over x-dependent local-time…

Mathematical Physics · Physics 2015-12-24 Petr Jizba , Vaclav Zatloukal

Face morphing is a problem in computer graphics with numerous artistic and forensic applications. It is challenging due to variations in pose, lighting, gender, and ethnicity. This task consists of a warping for feature alignment and a…

Computer Vision and Pattern Recognition · Computer Science 2024-09-24 Guilherme Schardong , Tiago Novello , Hallison Paz , Iurii Medvedev , Vinícius da Silva , Luiz Velho , Nuno Gonçalves

Grafakos and Sansing \cite{GS} have shown how to obtain directionally sensitive time-frequency decompositions in $L^2(\mr^n)$ based on Gabor systems in $\ltr;$ the key tool is the "ridge idea," which lifts a function of one variable to a…

Functional Analysis · Mathematics 2014-02-18 Ole Christensen , Brigitte Forster , Peter Massopust

Quantum measurements and the associated state changes are properly described in the language of instruments. We investigate the properties of a time continuous family of instruments associated with the recently introduced family of general…

Quantum Physics · Physics 2021-01-04 Nina Megier , Walter T. Strunz , Kimmo Luoma

Phase-space analysis or time-frequency analysis can be thought as Fourier analysis simultaneously both in time and in frequency, originating from signal processing and quantum mechanics. On groups having unitary Fourier transform, we…

Functional Analysis · Mathematics 2020-09-21 Ville Turunen

We develop a functional framework suitable for the treatment of partial differential equations and variational problems on evolving families of Banach spaces. We propose a definition for the weak time derivative that does not rely on the…

Analysis of PDEs · Mathematics 2023-02-17 Amal Alphonse , Diogo Caetano , Ana Djurdjevac , Charles M. Elliott

This article focuses on a new concept of quadratic variation for processes taking values in a Banach space $B$ and a corresponding covariation. This is more general than the classical one of M\'etivier and Pellaumail. Those notions are…

Probability · Mathematics 2013-08-02 Cristina Di Girolami , Giorgio Fabbri , Francesco Russo

The properties of the Gabor and Morlet transforms are examined with respect to the Fourier analysis of discretely sampled data. Forward and inverse transform pairs based on a fixed window with uniform sampling of the frequency axis can…

Data Analysis, Statistics and Probability · Physics 2013-07-23 Robert W. Johnson

A scattering transform defines a signal representation which is invariant to translations and Lipschitz continuous relatively to deformations. It is implemented with a non-linear convolution network that iterates over wavelet and modulus…

Computer Vision and Pattern Recognition · Computer Science 2011-12-07 Joan Bruna , Stéphane Mallat

Functional data analysis is ubiquitous in most areas of sciences and engineering. Several paradigms are proposed to deal with the dimensionality problem which is inherent to this type of data. Sparseness, penalization, thresholding, among…

Methodology · Statistics 2018-09-05 Rodney V. Fonseca , Aluísio Pinheiro

Biharmonic wave equations are of importance to various applications including thin plate analyses. In this work, the numerical approximation of their solutions by a $C^1$-conforming in space and time finite element approach is proposed and…

Numerical Analysis · Mathematics 2021-07-09 Markus Bause , Maria Lymbery , Kevin Osthues

Passive acoustic mapping (PAM) is a key imaging technique for characterizing cavitation activity in therapeutic ultrasound applications. Recent model-based beamforming algorithms offer high reconstruction quality and strong physical…

Image and Video Processing · Electrical Eng. & Systems 2026-01-13 Tatiana Gelvez-Barrera , Barbara Nicolas , Bruno Gilles , Adrian Basarab , Denis Kouamé

We develop a method of simulating the full quantum field dynamics of multi-mode multi-component Bose-Einstein condensates in a trap. We use the truncated Wigner representation to obtain a probabilistic theory that can be sampled. This…

Quantum Gases · Physics 2013-04-24 Bogdan Opanchuk , Peter D. Drummond

The time evolution of complex systems usually can be described through stochastic processes. These processes are measured at finite resolution, what necessarily reduces them to finite sequences of real numbers. In order to relate these data…

Condensed Matter · Physics 2007-05-23 D. M. Tavares , L. S. Lucena

We present a different symplectic point of view in the definition of weighted modulation spaces $M^{p,q}_m(\mathbb{R}^d)$ and weighted Wiener amalgam spaces $W(\mathcal{F} L^p_{m_1},L^q_{m_2})(\mathbb{R}^d)$. All of the classical…

Analysis of PDEs · Mathematics 2024-01-18 Elena Cordero , Gianluca Giacchi

The spectral theory for weakly stationary processes valued in a separable Hilbert space has known renewed interest in the past decade. Here we follow earlier approaches which fully exploit the normal Hilbert module property of the time…

Statistics Theory · Mathematics 2022-10-06 Amaury Durand , François Roueff

The non-relativistic version of the multi-temporal quantization scheme of relativistic particles in a family of non-inertial frames (see hep-th/0502194) is defined. At the classical level the description of a family of non-rigid…

High Energy Physics - Theory · Physics 2009-11-11 David Alba
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