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Functional Spectral Imaging (FSI) models image formation as the recovery of tissue surrogates such as density and stiffness from spectral perturbations of a self-adjoint elliptic operator. Rather than relying on reflectivity or relaxation…

Medical Physics · Physics 2025-10-21 Cesar Mello Fernando Medina da Cunha

The measurement of the pulse wave has proven to be a vital tool in medical diagnosis. Whereby most pulse wave measurements are carried out at extremities, this work proposes a system for measuring the pulse wave and the Pulse Arrival Time…

Signals comprised of a stream of short pulses appear in many applications including bio-imaging and radar. The recent finite rate of innovation framework, has paved the way to low rate sampling of such pulses by noticing that only a small…

Information Theory · Computer Science 2015-05-18 Ronen Tur , Yonina C. Eldar , Zvi Friedman

We present a pressure sensor based on a Michelson interferometer, for use in photoacoustic tomography. Quadrature phase detection is employed allowing measurement at any point on the mirror surface without having to retune the…

Optics · Physics 2013-07-31 Rory W. Speirs , Alexis I. Bishop

The power spectral density in Fourier frequency domain, and the different variants of the Allan deviation (ADEV) in dependence on the averaging time are well established tools to analyse the fluctuation properties and frequency instability…

Data Analysis, Statistics and Probability · Physics 2015-07-21 Erik Benkler , Christian Lisdat , Uwe Sterr

Ultrasound shear wave elastography (SWE) is a noninvasive way to measure stiffness of soft tissue for medical diagnosis. In SWE imaging, an acoustic radiation force induces tissue displacement, which creates shear waves (SWs) that travel…

Signal Processing · Electrical Eng. & Systems 2024-07-31 Md. Jahin Alam , Md. Kamrul Hasan

Complex frequency excitations, oscillating signals whose amplitude decreases exponentially in time, have recently been demonstrated to significantly increase the effective quality factor of mechanical resonators. In this work, we…

Classical Physics · Physics 2026-05-14 Wenbo Li , Raj Kumar Pal

To exploit the wealth of information carried by the short transient radio pulses from air showers, the frequency spectra of the signals have to be investigated. Here, we study the spectral content of radio signals produced by inclined…

Instrumentation and Methods for Astrophysics · Physics 2024-07-29 Sara Martinelli , Felix Schlueter , Tim Huege

The acoustic radiation force exerted on a small sphere located at the focus of an ultrasonic beam is measured in a soft gel. It is proved to evolve quadratically with the local amplitude of the acoustic field. Strong oscillations of the…

Soft Condensed Matter · Physics 2017-06-28 Pierre Lidon , Louis Villa , Nicolas Taberlet , Sébastien Manneville

Problems of pulse excitation in an acoustic waveguide with a flexible wall and in an acoustic half-space with a flexible wall are studied. In both cases the flexible wall is described by a thin plate equation. The solutions are written as…

Classical Physics · Physics 2021-11-10 M. A. Mironov , A. V. Shanin , A. I. Korolkov , K. S. Kniazeva

Multiple scattering of radio waves by artificial random irregularities HF-induced in the ionosphere F region may cause significant attenuation of both ordinary and extraordinary waves together with common anomalous absorption of ordinary…

Many phenomena are described by bivariate signals or bidimensional vectors in applications ranging from radar to EEG, optics and oceanography. The time-frequency analysis of bivariate signals is usually carried out by analyzing two separate…

Methodology · Statistics 2016-09-09 Julien Flamant , Nicolas Le Bihan , Pierre Chainais

Timing noise in pulsars is often modelled with a Fourier-basis Gaussian process that follows a power law with periodic boundary conditions on the observation time, $T_\mathrm{span}$. However the actual noise processes can extend well below…

High Energy Astrophysical Phenomena · Physics 2023-06-14 Michael J. Keith , Iuliana C. Niţu

The power spectrum, as a statistic in Fourier space, is commonly numerically calculated using the fast Fourier transform method to efficiently reduce the computational costs. To alleviate the systematic bias known as aliasing due to the…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-24 Yipeng Wang , Yu Yu

Audio compression has become one of the basic multimedia technologies. Choosing an efficient compression scheme that is capable of preserving the signal quality while providing a high compression ratio is desirable in the different…

Information Theory · Computer Science 2014-03-13 Hossam M. Kasem , Maha El-Sabrouty

The purpose of this work is to demonstrate a robust and clinically validated method for correcting sound speed aberrations in medical ultrasound. We propose a correction method that calculates focusing delays directly from the observed…

The interaction of ultrasonic waves with fluid-embedded viscoelastic plates, pipes, and shells, have been subject to extensive theoretical and experimental studies over several decades. In normal-incidence through-transmission measurements…

Instrumentation and Detectors · Physics 2016-04-11 Magne Aanes , Kjetil Daae Lohne , Per Lunde , Magne Vestrheim

We consider the problem of estimating a Fourier-sparse signal from noisy samples, where the sampling is done over some interval $[0, T]$ and the frequencies can be "off-grid". Previous methods for this problem required the gap between…

Data Structures and Algorithms · Computer Science 2016-09-07 Xue Chen , Daniel M. Kane , Eric Price , Zhao Song

For given computational resources, the accuracy of plasma simulations using particles is mainly held back by the noise due to limited statistical sampling in the reconstruction of the particle distribution function. A method based on…

Computational Physics · Physics 2009-09-03 Romain Nguyen van yen , Diego del-Castillo-Negrete , Kai Schneider , Marie Farge , Guangye Chen

Spread-spectrum signals are increasingly adopted in fields including communications, testing of electronic systems, Electro-Magnetic Compatibility (EMC) enhancement, ultrasonic non-destructive testing. This paper considers the synthesis of…

Data Analysis, Statistics and Probability · Physics 2014-12-22 Sergio Callegari