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Time-frequency images (TFIs) provide a joint time-frequency representation of a signal and have become an effective tool for analyzing, characterizing, and processing non-stationary signals. Deep learning (DL) techniques have become…

Signal Processing · Electrical Eng. & Systems 2023-02-23 Mehmet Parlak

A variational Bayesian inference for measured wave intensity, such as X-ray intensity, is proposed in this paper. The data is popular to obtain information about unobservable features of an object, such as a material sample and the…

Machine Learning · Computer Science 2024-11-12 Akinori Asahara , Yoshihiro Osakabe , Yamamoto Mitsuya , Hidekazu Morita

In this paper, we study both the direct and inverse random source problems associated with the multi-term time-fractional diffusion-wave equation driven by a fractional Brownian motion. Regarding the direct problem, the well-posedness is…

Analysis of PDEs · Mathematics 2023-11-03 Xiaoli Feng , Qiang Yao , Peijun Li , Xu Wang

We present a theoretical analysis of quantum decay in which the survival probability is replaced by a decay rate that is equal to the absolute value squared of the wave function in the time representation. The wave function in the time…

Quantum Physics · Physics 2013-07-03 Rafael de la Madrid

A central problem in signal processing and communications is to design signals that are compact both in time and frequency. Heisenberg's uncertainty principle states that a given function cannot be arbitrarily compact both in time and…

Information Theory · Computer Science 2014-01-17 Reza Parhizkar , Yann Barbotin , Martin Vetterli

We propose a new solution to the blind source separation problem that factors mixed time-series signals into a sum of spatiotemporal modes, with the constraint that the temporal components are intrinsic mode functions (IMF's). The key…

Numerical Analysis · Mathematics 2018-06-25 Seth M. Hirsh , Bingni W. Brunton , J. Nathan Kutz

This correspondence presents an efficient method for reconstructing a band-limited signal in the discrete domain from its crossings with a sine wave. The method makes it possible to design A/D converters that only deliver the crossing…

Information Theory · Computer Science 2016-11-17 J. Selva

We formulate a model for intermittent communication that can capture bursty transmissions or a sporadically available channel, where in either case the receiver does not know a priori when the transmissions will occur. Focusing on the…

Information Theory · Computer Science 2017-03-20 Mostafa Khoshnevisan , J Nicholas Laneman

According to a recent paper by G. Vignale [Phys. Rev. A 77, 062511 (2008), arXiv:0803.2727], the problems arising in the original derivation of time-dependent density functional theory (TDDFT) based on the Runge-Gross (RG) action-integral…

Other Condensed Matter · Physics 2012-08-07 J. Schirmer

The multifrequency electrical impedance tomography consists in retrieving the conductivity distribution of a sample by injecting a finite number of currents with multiple frequencies. In this paper we consider the case where the…

Numerical Analysis · Mathematics 2017-04-18 Habib Ammari , Faouzi Triki , Chun-Hsiang Tsou

We study invariant solutions of a certain class of time-fractional diffusion-wave equations with variable coefficients via Lie symmetry analysis. In physics, the fractional diffusion equation describes transport dynamics that are governed…

This study investigates an inverse problem associated with a time-fractional HIV infection model incorporating nonlinear diffusion. The model describes the dynamics of uninfected target cells, infected cells, and free virus particles, where…

Numerical Analysis · Mathematics 2025-04-01 Mohamed BenSalah , Salih Tatar , Suleyman Ulusoy

In order to efficiently image a non-absorbing sample (a phase object), dedicated phase contrast optics are required. Typically, these optics are designed with the assumption that the sample is weakly scattering, implying a linear relation…

Optics · Physics 2020-10-22 Stewart Koppell , Mark Kasevich

This paper studies the problem of fault detection and estimation (FDE) for linear time-invariant (LTI) systems with a particular focus on frequency content information of faults, possibly as multiple disjoint continuum ranges, and under…

Systems and Control · Electrical Eng. & Systems 2024-10-02 Jingwei Dong , Kaikai Pan , Sergio Pequito , Peyman Mohajerin Esfahani

Infinite impulse response filters are an essential building block of many time-varying audio systems, such as audio effects and synthesisers. However, their recursive structure impedes end-to-end training of these systems using automatic…

Audio and Speech Processing · Electrical Eng. & Systems 2024-10-22 Chin-Yun Yu , Christopher Mitcheltree , Alistair Carson , Stefan Bilbao , Joshua D. Reiss , György Fazekas

We propose a new algorithm for time stretching music signals based on the theory of nonstationary Gabor frames (NSGFs). The algorithm extends the techniques of the classical phase vocoder (PV) by incorporating adaptive time-frequency (TF)…

Sound · Computer Science 2017-09-14 Emil Solsbæk Ottosen , Monika Dörfler

Signal decomposition is an effective tool to assist the identification of modal information in time-domain signals. Two signal decomposition methods, including the empirical wavelet transform (EWT) and Fourier decomposition method (FDM),…

Signal Processing · Electrical Eng. & Systems 2023-01-31 Wei Zhou , Zhongren Feng , Y. F. Xu , Xiongjiang Wang , Hao Lv

Dynamic graph signal processing provides a principled framework for analyzing time-varying data defined on irregular graph domains. However, existing joint time-vertex transforms such as the joint time-vertex fractional Fourier transform…

Signal Processing · Electrical Eng. & Systems 2025-11-21 Manjun Cui , Ziqi Yan , Yangfan He , Zhichao Zhang

The frequency-domain approach (FDA) to transient analysis of the boundary element method, although is appealing for engineering applications, is computationally expensive. This paper proposes a novel adaptive frequency sampling (AFS)…

Numerical Analysis · Mathematics 2016-02-09 Jinyou Xiao , Junjie Rong , Wenjing Ye , Chuanzeng Zhang

Analyzing time series in the frequency domain enables the development of powerful tools for investigating the second-order characteristics of multivariate processes. Parameters like the spectral density matrix and its inverse, the coherence…

Methodology · Statistics 2024-01-19 Jonas Krampe , Efstathios Paparoditis