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Resonance frequencies can provide useful information on the deformation occurring during fracturing experiments or $CO_2$ management, complementary to the microseismic event distribution. An accurate time-frequency representation is of…

Geophysics · Physics 2013-01-08 Roberto H. Herrera , Jean-Baptiste Tary , Mirko van der Baan

There have been a number of papers written on semi-parametric estimation methods of the long-memory exponent of a time series, some applied, others theoretical. Some using Fourier methods, others using a wavelet-based technique. In this…

Statistics Theory · Mathematics 2008-01-29 Gilles Fay , Eric Moulines , François Roueff , Murad S. Taqqu

This study puts forward a generalization of the short-time Fourier-based Synchrosqueezing Transform using a new local estimate of instantaneous frequency. Such a technique enables not only to achieve a highly concentrated time-frequency…

Signal Processing · Electrical Eng. & Systems 2020-04-21 Duong-Hung Pham , Sylvain Meignen

Experiments in many fields of science and engineering yield data in the form of time series. The Fourier and wavelet transform-based nonparametric methods are used widely to study the spectral characteristics of these time series data.…

Data Analysis, Statistics and Probability · Physics 2009-11-13 Mukeshwar Dhamala , Govindan Rangarajan , Mingzhou Ding

Gravitational-wave memory is characterized by a signal component that persists after a transient signal has decayed. Treating such signals in the frequency domain is non-trivial, since discrete Fourier transforms assume periodic signals on…

General Relativity and Quantum Cosmology · Physics 2024-12-17 Jorge Valencia , Rodrigo Tenorio , Maria Rosselló-Sastre , Sascha Husa

In this paper we investigate new results on the theory of superoscillations using time-frequency analysis tools and techniques such as the short-time Fourier transform (STFT) and the Zak transform. We start by studying how the short-time…

Functional Analysis · Mathematics 2024-07-18 Daniel Alpay , Antonino De Martino , Kamal Diki , Daniele C. Struppa

Aims. The wavelet transform has been used as a powerful tool for treating several problems in astrophysics. In this work, we show that the time-frequency analysis of stellar light curves using the wavelet transform is a practical tool for…

Instrumentation and Methods for Astrophysics · Physics 2014-09-05 J. P. Bravo , S. Roque , R. Estrela , I. C. Leão , J. R. De Medeiros

A set of semi-analytical techniques based on Fourier analysis is used to solve wave scattering problems in variously shaped waveguides with varying normal admittance boundary conditions. Key components are newly developed conformal mapping…

Mathematical Physics · Physics 2015-06-02 Anders Andersson , Borje Nilsson , Thomas Biro

New experimental techniques based on non-linear ultrafast spectroscopies have been developed over the last few years, and have been demonstrated to provide powerful probes of quantum dynamics in different types of molecular aggregates,…

Recent CNN and Transformer-based models tried to utilize frequency and periodicity information for long-term time series forecasting. However, most existing work is based on Fourier transform, which cannot capture fine-grained and local…

Machine Learning · Computer Science 2024-01-05 Peiyuan Liu , Beiliang Wu , Naiqi Li , Tao Dai , Fengmao Lei , Jigang Bao , Yong Jiang , Shu-Tao Xia

Within the expansive domain of optical sciences, achieving the precise characterization of light beams stands as a fundamental pursuit, pivotal for various applications, including telecommunications and imaging technologies. This study…

In view of recently demonstrated joint use of novel Fourier-transform techniques and effective high-accuracy frequency domain solvers related to the Method of Moments, it is argued that a set of transformative innovations could be developed…

Computational Physics · Physics 2024-11-11 Thomas G. Anderson , Mark Lyon , Tao Yin , Oscar P. Bruno

Several differentiating algorithms of the noisy signals are considered. The proposed wavelet based technique is compared with others based on the Fourier transform and the finite differences. The accuracy of the calculations for different…

Mathematical Physics · Physics 2007-05-23 I. Patrickeyev , R. Stepanov , P. Frick

In this paper, we consider multiple signals sharing same instantaneous frequencies. This kind of data is very common in scientific and engineering problems. To take advantage of this special structure, we modify our data-driven…

Information Theory · Computer Science 2015-07-09 Thomas Y. Hou , Zuoqiang Shi

The special affine Fourier transform (SAFT) is a promising tool for analyzing non-stationary signals with more degrees of freedom. However, the SAFT fails in obtaining the local features of non-transient signals due to its global kernel and…

Functional Analysis · Mathematics 2020-06-11 Firdous A. Shah , Azhar Y. Tantary , Aajaz A. Teali

It is shown that any convolution operator in the time domain can be represented exactly as a multiplication operator in the time-scale (wavelet) domain. The Mellin transform gives a one-to-one correspondence between frequency filters…

Mathematical Physics · Physics 2007-05-23 Gerald Kaiser

We report experimental results of parallel measurement of spectral components of the light. The temporal fluctuations of an optical field mixed with a separate reference are recorded with a high throughput complementary metal oxide…

Optics · Physics 2008-11-26 Michael Atlan , Michel Gross

This paper introduces a design method for densergraph-frequency graph Fourier frames (DGFFs) to enhance graph signal processing and analysis. The graph Fourier transform (GFT) enables us to analyze graph signals in the graph spectral domain…

Signal Processing · Electrical Eng. & Systems 2025-03-18 Kaito Nitani , Seisuke Kyochi

When sampling multiple signals, the correlation between the signals can be exploited to reduce the overall number of samples. In this paper, we study the sampling theory of multiple correlated signals, using correlation to sample them at…

Signal Processing · Electrical Eng. & Systems 2022-10-11 Zhongyi Ni , Feng Ji , Hang Sheng , Hui Feng , Bo Hu

This work considers uncertainty relations on time frequency distributions from a signal processing viewpoint. An uncertainty relation on the marginalizable time frequency distributions is given. A result from quantum mechanics is used on…

Signal Processing · Electrical Eng. & Systems 2021-04-27 Eren Berk Kama , Mustafa Kuzuoğlu