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Oscillatory processes are central for the understanding of the neural bases of cognition and behaviour. To analyse these processes, time-frequency (TF) decomposition methods are applied and non-parametric cluster-based statistical procedure…

Quantitative Methods · Quantitative Biology 2018-01-30 Christian Beste , Daniel Kaping , Tzvetomir Tzvetanov

A target recognition framework relying on near-field integrated sensing and communication (ISAC) systems is proposed. By exploiting the distance-dependent spatial signatures provided by the near-field spherical wavefront, high-accuracy…

Signal Processing · Electrical Eng. & Systems 2026-03-17 Zongyao Zhao , Zhaolin Wang , Lincong Han , Jing Jin , Kaibin Huang

We consider the continuous-time version of our recently proposed quantum theory of optical temporal phase and instantaneous frequency [Tsang, Shapiro, and Lloyd, Phys. Rev. A 78, 053820 (2008)]. Using a state-variable approach to…

Quantum Physics · Physics 2009-05-21 Mankei Tsang , Jeffrey H. Shapiro , Seth Lloyd

We investigate a simple forced harmonic oscillator with a natural frequency varying with time. It is shown that the time evolution of such a system can be written in a simplified form with Fresnel integrals, as long as the variation of the…

Classical Physics · Physics 2020-09-16 Toshihiko Hiraiwa , Kouichi Soutome , Hitoshi Tanaka

Causal inference from longitudinal observational data is a challenging problem due to the difficulty in correctly identifying the time-dependent confounders, especially in the presence of latent time-dependent confounders. Instrumental…

Machine Learning · Computer Science 2023-12-13 Debo Cheng , Ziqi Xu , Jiuyong Li , Lin Liu , Jixue Liu , Wentao Gao , Thuc Duy Le

Measurement devices always add noise to the signal of interest and it is necessary to evaluate the variance of the results. This article focuses on stationary random processes whose Power Spectrum Density is a power law of frequency. For…

Data Analysis, Statistics and Probability · Physics 2013-05-20 Benjamin Lenoir

It is the purpose of the paper to describe the virtues of time-frequency methods for signal processing applications, having astronomical time series in mind. Different methods are considered and their potential usefulness respectively…

Astrophysics · Physics 2009-11-07 R. Vio , W. Wamsteker

In the recent papers [1-4] including above paper time modulated frequency diverse arrays (FDAs) have been presented to obtain time invariant spatial patterns. The presented FDAs in [1-3] have the feature of time-invariant spatial focusing…

Signal Processing · Electrical Eng. & Systems 2019-12-03 Mahdi Fartookzadeh

Long-term time series forecasting is a long-standing challenge in various applications. A central issue in time series forecasting is that methods should expressively capture long-term dependency. Furthermore, time series forecasting…

Machine Learning · Computer Science 2024-11-06 Xingyu Zhang , Siyu Zhao , Zeen Song , Huijie Guo , Jianqi Zhang , Changwen Zheng , Wenwen Qiang

The invariance principle, through which the steady-state behavior of nonlinear systems was introduced by Isidori and Byrnes, is leveraged in this article to bring forth a unifying characterization of the frequency response of nonlinear…

Systems and Control · Electrical Eng. & Systems 2026-04-16 Alessio Moreschini , Matteo Scandella

An integrate-and-fire time-encoding machine (IF-TEM) is an effective asynchronous sampler that translates amplitude information into non-uniform time sequences. In this work, we propose a novel Adaptive IF-TEM (AIF-TEM) approach. This…

Signal Processing · Electrical Eng. & Systems 2026-03-18 Aseel Omar , Alejandro Cohen

The Fast Fourier Transform (FFT) is a fundamental tool for signal analysis, widely used across various fields. However, traditional FFT methods encounter challenges in adjusting the frequency bin interval, which may impede accurate spectral…

Data Structures and Algorithms · Computer Science 2024-03-27 Haichao Xu

The phenomenon of frequency and phase synchronization in stochastic systems requires a revision of concepts originally phrased in the context of purely deterministic systems. Various definitions of an instantaneous phase are presented and…

Statistical Mechanics · Physics 2009-11-07 Jan A. Freund , Lutz Schimansky-Geier , Peter Haenggi

We study the real-time dynamics retrieval from a time series via the time-frequency (TF) analysis with the minimal latency guarantee. While different from the well-known intrinsic latency definition in the filter design, a rigorous…

Multimedia · Computer Science 2016-06-30 Li Su , Hau-tieng Wu

In this work, we present a new technique for the decomposition of multivariate data, which we call Multivariate Fast Iterative Filtering (MvFIF) algorithm. We study its properties, proving rigorously that it converges in finite time when…

Numerical Analysis · Mathematics 2021-11-04 Antonio Cicone , Enza Pellegrino

This paper is concerned with uniqueness in inverse acoustic scattering with phaseless far-field data at a fixed frequency. The main difficulty of this problem is the so-called translation invariance property of the modulus of the far-field…

Analysis of PDEs · Mathematics 2017-09-26 Xiaoxu Xu , Bo Zhang , Haiwen Zhang

Fractional Interference Alignment (FIA) is a transmission scheme which achieves any value between [0,1] for the Symbols transmitted per Antenna per Channel use (SpAC). FIA was designed in [1] specifically for Finite Alphabet (FA) signals,…

Information Theory · Computer Science 2013-12-06 B Hari Ram , G Kanchana Vaishnavi , K Giridhar

Frequency is a central concept in Mathematics, Physics, and Signal Processing. It is the main tool for describing the oscillatory behavior of signals, which is usually argued to be the manifestation of some of their key features, depending…

Signal Processing · Electrical Eng. & Systems 2021-05-28 Móises Soto-Bajo , Andrés Fraguela Collar , Javier Herrera Vega , Raúl Felipe-Sosa

The paper introduces the concept of complex frequency. The imaginary part of the complex frequency is the variation with respect of a synchronous reference of the local bus frequency as commonly defined in power system studies. The real…

Systems and Control · Electrical Eng. & Systems 2026-03-24 Federico Milano

We study the volatility functional inference by Fourier transforms. This spectral framework is advantageous in that it harnesses the power of harmonic analysis to handle missing data and asynchronous observations without any artificial time…

Statistics Theory · Mathematics 2019-11-07 Richard Y. Chen