Results 41 to 50 of about 5,320,784 (238)

An Inverse Problem for Localization Operators

, 2012
A classical result of time-frequency analysis, obtained by I. Daubechies in 1988, states that the eigenfunctions of a time-frequency localization operator with circular localization domain and Gaussian analysis window are the Hermite functions.
, Daubechies I, Gröchenig K, Luís Daniel Abreu, Mallat S, Monika Dörfler, Paul T   +6 more
core   +1 more source

Reduced‐order electromagnetic transient model based on equivalent flux linkage derivative for induction motors under voltage sag condition

IET Electric Power Applications
Precise electromagnetic transient simulation of induction motors (IMs) under voltage sag condition is necessary in Electro‐Magnetic Transient Programme. Although traditional fifth‐order model can accurately reflect the electromagnetic transient behaviour
Guangliang Yang, Tongyu Guan, Jinping Kang, Yang Zhan, Guorui Xu, Haisen Zhao   +5 more
doaj   +1 more source

The Validity of Ultra-Short-Term Heart Rate Variability during Cycling Exercise

Sensors, 2023
Ultra-short-term heart rate variability (HRV) has been validated in the resting state, but its validity during exercise is unclear. This study aimed to examine the validity in ultra-short-term HRV during exercise considering the different exercise ...
Yukiya Tanoue, Shihoko Nakashima, Tomohiro Komatsu, Miki Kosugi, Saki Kawakami, Shotaro Kawakami, Ryoma Michishita, Yasuki Higaki, Yoshinari Uehara   +8 more
doaj   +1 more source

Analysis of nonlinear oscillators using volterra series in the frequency domain Part I : convergence limits [PDF]

, 2009
The Volterra series representation is a direct generalisation of the linear convolution integral and has been widely applied in the analysis and design of nonlinear systems, both in the time and the frequency domain.
Billings, S.A., Li, L.M.
core  

How Can the Optical Variation Properties of Active Galactic Nuclei Be Unbiasedly Measured?

The Astrophysical Journal
The variability of active galactic nuclei (AGNs) is ubiquitous, but has not yet been understood. Measuring the optical variation properties of AGNs, such as the variation timescale and amplitude, and then correlating them with their fundamental physical ...
Xu-Fan Hu, Zhen-Yi Cai, Jun-Xian Wang
doaj   +1 more source

Comparative Studies between Frequency Domain Analysis and Time Domain Analysis on Free-Field One-Dimensional Shear Wave Propagation

Applied Mechanics
In Korea, the underground silo structure for low- and intermediate-level radioactive waste disposal facilities has been constructed and operated since 2014.
Sun-Hoon Kim, Kwang-Jin Kim
doaj   +1 more source

Statistical analysis of audible noise generated by AC corona discharge from single corona sources

High Voltage, 2018
Time-domain waveforms of sound pressure pulses generated by alternate current (AC) corona discharge from single corona sources are measured. The pulse amplitude and time interval of sound pressure pulses in positive and negative half cycles are analysed ...
Xuebao Li, Jing Wang, Jing Wang, Tiebing Lu, Xiang Cui   +4 more
doaj   +1 more source

Profiling the propagation of error from PPG to HRV features in a wearable physiological-monitoring device

Healthcare Technology Letters, 2018
Wearable physiological monitors are becoming increasingly commonplace in the consumer domain, but in literature there exists no substantive studies of their performance when measuring the physiology of ambulatory patients.
Davide Morelli, Leonardo Bartoloni, Michele Colombo, David Plans, David A. Clifton   +4 more
doaj   +1 more source

Commutation failure caused by AC filter switching In HVDC system

The Journal of Engineering, 2019
Switching AC filter may cause harmonic impact, which may lead to commutation failure of HVDC system. Here, the commutation failure mechanism of HVDC system caused by AC filter switching is studied.
Meng Liu, Lei Zheng, Fangfang Shi, Kuan Li   +3 more
doaj   +1 more source

Time evolutions of scalar field perturbations in $D$-dimensional Reissner-Nordstr\"om Anti-de Sitter black holes

, 2016
Reissner-Nordstr\"om Anti-de Sitter (RNAdS) black holes are unstable against the charged scalar field perturbations due to the well-known superradiance phenomenon.
Li, Ran, Zhang, Hongbao, Zhao, Junkun
core   +2 more sources