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Journal articles on the topic 'Fluctuation signal'

Author: Grafiati

Published: 3 June 2025

Last updated: 31 July 2025

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1

T. Khan, M. A. Khan, A. Kabir, M. Atif, and D. Ahmad. "LOCAL MESHLESS ALGORITHM FOR TOTAL VARIATION-BASED MODEL FOR SIGNAL RESTORATION HAVING ADDITIVE NOISE." Pakistan Journal of Science 76, no. 03 (2024): 492–501. https://doi.org/10.57041/vol76iss03pp492-501.

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A noisy signal converts the signal to another signal containing fluctuation called signal fluctuation. This fluctuation in signal is a common factor in signal processing. In this article, we introduce a Local Meshless Collocation Method (LMCM) for the numerical solution of the Euler- Lagrange Partial Differential Equation (EL-PDE) associated with the Total Variation (TV)-based model for removing additive noise from the given data signals. This method uses the mul-ti-quadric Radial Basis Function (MQ-RBF) as the basis function. These features will eliminate the fluctuations from the given noisy

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Kato, Taro, Takuya Kitamura, Fumiya Maehara, et al. "Calculation of 1/f Fluctuation from Sound Signal and Comfort Evaluation." Applied Sciences 12, no. 19 (2022): 9425. http://dx.doi.org/10.3390/app12199425.

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Providing a comfortable sound for users is an important factor for high-value products. Therefore, many studies have investigated pleasant sound levels for developing and manufacturing new products. Notably, sounds containing 1/f fluctuations provide a relaxing effect in humans. There are many studies on the influence of sound signals, including 1/f fluctuations; however, the verification of fluctuations, including sound signals, has not been performed. In this study on fluctuation, the discrete Fourier transform was used to directly calculate the time of the sound signal. We evaluated the dur

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Syahrial, Syahrial, Melinda Melinda, Junidar Junidar, Safrizal Razali, and Zulhelmi Zulhelmi. "Application of the Savitzky-Golay filter in multi-spectral signal processing." Sriwijaya Electrical and Computer Engineering Journal 1, no. 1 (2024): 9–19. http://dx.doi.org/10.62420/selco.v1i1.5.

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Multi-spectral signals are the result of the interaction between electromagnetic energy and the test material, which is then displayed by the signal fluctuation pattern of the test material. Signal fluctuations are inaccuracies in the peak amplitude of a signal caused by noise in the data. This fluctuation pattern reflects the properties of the test material, especially in this case H2O. To overcome this problem, it is necessary to use the right filter to smooth the signal and reduce the noise in the data so that the fluctuation pattern obtained is clearer and more accurate. This research invo

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Meng, Tao, Huanchang Wei, Feng Gao, and Huichao Shi. "Measurement of Flow Fluctuation in the Flow Standard Facility Based on Singular Value Decomposition." Sensors 21, no. 20 (2021): 6850. http://dx.doi.org/10.3390/s21206850.

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In order to accurately evaluate the flow stability of the flow standard facility, the flow fluctuation in the standard facility needs to be accurately measured. However, the flow fluctuation signal is always superimposed with the fluctuation signal of the measuring flowmeter or measurement system (mainly noise), which leads to inaccurate measurement of the flow fluctuation and even an unreliable evaluation result of the flow stability. In addition, when there are multiple fluctuation sources, flow fluctuations with different frequencies are superimposed together, which is extremely unfavorable

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Gong, Jiangkun, Jun Yan, Deren Li, et al. "Measurement and Analysis of Radar Signals Modulated by the Respiration Movement of Birds." Applied Sciences 12, no. 16 (2022): 8101. http://dx.doi.org/10.3390/app12168101.

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Once, bird respiration was thought to be responsible for the 10 dB-level fluctuations in the radar signals of birds. Although, recently, many researchers provide evidence against this, there are almost no quantification measurements of the contribution of respiration to bird signals in microwave anechoic chambers. Here, we first measured the radar signals modulated by the respiration of birds in a microwave anechoic chamber. Theoretically, the simulated signal fluctuation caused by the respiration of a 1 kg standard avian target (SAT) duck is approximately 1.2 dB based on the water sphere mode

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Sims-Williams, D. B., and D. A. Luck. "Transfer function characterization of pressure signal tubes for the measurement of large amplitude pressure fluctuations." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 221, no. 6 (2007): 707–13. http://dx.doi.org/10.1243/0954406jmes582.

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The measurement of fluctuating pressures in gasses is relevant to a wide range of fluid flow applications. The frequency response of pressure measurement systems using remote transducers is usually limited by the response of the connecting tubing. For small fluctuation levels it is well established that the signal distortion can be corrected using a transfer function technique. This work extends the approach to include the more challenging issue of large amplitude fluctuations where the transfer function is strongly dependent on the fluctuation amplitude as well as frequency. The tubing transf

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Xiao, Hui Fang, Xiao Jun Zhou, and Yi Min Shao. "An Ensemble Dynamic Time Domain Averaging Method for Gear Fault Detection without Tachometer." Key Engineering Materials 572 (September 2013): 439–42. http://dx.doi.org/10.4028/www.scientific.net/kem.572.439.

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Time Domain Averaging (TDA) has been widely used for fault detection. However, it cannot reveal signal characteristics accurately in conditions of speed fluctuation and no tachometer. Empirical mode decomposition (EMD) helps to extract physically meaningful components from the singles. Dynamic Time Warping (DTW) can solve inconsistence in signal lengths per rotation due to speed fluctuation. Utilizing the advantages of EMD, DTW and TDA, an ensemble dynamic-time domain averaging (ED-TDA) algorithm is proposed for gear fault detection without tachometer. First, the selected intrinsic mode functi

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Jia, Wang, Mingjun Diao, Lei Jiang, and Guibing Huang. "Time-Frequency Characteristics of Fluctuating Pressure on the Bottom of the Stilling Basin with Step-Down Floor Based on Hilbert–Huang Transform." Mathematical Problems in Engineering 2021 (September 6, 2021): 1–12. http://dx.doi.org/10.1155/2021/7246488.

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Fluctuating pressure is an important feature of the bottom of a stilling basin with step-down floor. To analyze the frequency domain characteristics and energy distribution of this fluctuating pressure, the Hilbert–Huang transform (HHT) method is used. First, empirical mode decomposition is performed on the pressure fluctuation signal to obtain a number of intrinsic mode functions (IMFs), and then the Hilbert transformation is performed on each IMF to obtain the Hilbert spectrum and marginal spectrum for characterizing the pressure fluctuation signal. The results show that the fluctuating pres

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Padmanabhan, Vardhini, Punitha Namadurai, and Ramakrishnan Swaminathan. "Analysis of Preterm Pregnancies using Empirical Mode Decomposition based Fractal Features." Current Directions in Biomedical Engineering 7, no. 2 (2021): 783–86. http://dx.doi.org/10.1515/cdbme-2021-2200.

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Abstract Preterm birth (gestational age < 37 weeks) is a serious pregnancy related complication that could lead to fetal morbidity and mortality. Monitoring the activity of uterus is considered to be crucial for the early diagnosis of preterm birth. Uterine Electromyography (uEMG) is a non-invasive technique that provides a quantitative measure of uterine activity from the abdominal surface. In this work, an attempt has been made to characterize preterm uEMG signals using Empirical Mode Decomposition based Detrended Fluctuation Analysis (EMD-DFA). Preterm signals with varied gestational age

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Dai, Weiying, Gopal Varma, Rachel Scheidegger, and David C. Alsop. "Quantifying fluctuations of resting state networks using arterial spin labeling perfusion MRI." Journal of Cerebral Blood Flow & Metabolism 36, no. 3 (2015): 463–73. http://dx.doi.org/10.1177/0271678x15615339.

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Blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) has been widely used to investigate spontaneous low-frequency signal fluctuations across brain resting state networks. However, BOLD only provides relative measures of signal fluctuations. Arterial Spin Labeling (ASL) MRI holds great potential for quantitative measurements of resting state network fluctuations. This study systematically quantified signal fluctuations of the large-scale resting state networks using ASL data from 20 healthy volunteers by separating them from global signal fluctuations and fluctuatio

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Lin, Wenfeng, and Xinghao Tian. "Research on Leak Detection of Low-Pressure Gas Pipelines in Buildings Based on Improved Variational Mode Decomposition and Robust Kalman Filtering." Sensors 24, no. 14 (2024): 4590. http://dx.doi.org/10.3390/s24144590.

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Aiming at the complex characteristics of negative pressure waves in low-pressure pipelines inside of buildings, we proposed an estimation method of pressure fluctuation trends based on the robust Kalman filter and the improved VMD, which can be used for leakage detection. The reconstructed baseline signal can accurately describe the fluctuation trend of the negative pressure wave after the pressure drop, and quantitatively express the characteristic difference between the leakage condition and the gas usage condition. The robust Kalman filter was used to estimate the pressure fluctuations. The

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Hong, J. Y., Ch P. Ritz, E. J. Powers, and S. B. Kim. "Plasma fluctuation signal analysis tool." Review of Scientific Instruments 59, no. 8 (1988): 1751–53. http://dx.doi.org/10.1063/1.1140100.

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PHINYOMARK, ANGKOON, PORNCHAI PHUKPATTARANONT, CHUSAK LIMSAKUL, and MONTRI PHOTHISONOTHAI. "ELECTROMYOGRAPHY (EMG) SIGNAL CLASSIFICATION BASED ON DETRENDED FLUCTUATION ANALYSIS." Fluctuation and Noise Letters 10, no. 03 (2011): 281–301. http://dx.doi.org/10.1142/s0219477511000570.

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Electromyography (EMG) signal is a useful signal in various medical and engineering applications. To extract the useful information in the EMG signal, feature extraction method should be performed. The extracted features of the EMG signal are usually calculated based on linear or statistical methods, but the EMG signal exhibits the nonlinear and more complex in the properties. With recent advances in nonlinear analysis we are proposing the study of the EMG signals from upper-limb movements using Detrended Fluctuation Analysis (DFA) method. This study used EMG signals obtained from eight upper-

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JULIEN, M. H., and A. CAMPANA. "INTENSITY OF NMR SIGNAL IN La1.90Sr0.10CuO4: CHARGE vs. SPIN FREEZING." International Journal of Modern Physics B 14, no. 25n27 (2000): 2791–96. http://dx.doi.org/10.1142/s0217979200002909.

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We report on 139 La NMR and 63 Cu NQR measurements in La 1.90 Sr 0.10 CuO 4 above its superconducting transition temperature. We find that the intensity of the signal integrated on frequencies decreases significantly on cooling from 60 K to 28 K for 63 Cu nuclei (wipeout effect), while it remains constant for 139 La nuclei in this T-range. The distribution of 139 La spin-lattice relaxation time (T1) values in the "wipeout regime" reveals a spread of electronic fluctuation frequencies in CuO 2 planes. A simple calculation, for spin fluctuation induced relaxation, shows that 63 Cu nuclei at site

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Laroche, Gaétan, Jean Giroux, Alain Bordeleau, and Jean-Marc Garneau. "Investigation of Electrical and Optical Subtractions Using Two Input-Port and Two Output-Port FT-IR Spectrometers." Applied Spectroscopy 48, no. 3 (1994): 356–62. http://dx.doi.org/10.1366/0003702944028362.

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Two FT-IR spectrometers, each using two input ports and two output ports, have been used to minimize the effect of background noise and source fluctuation noise in infrared emission spectra of various sources. Blackbody sources, propane/air flames, and infrared flares have been studied, and spectra were recorded in the spectral region ranging from 1.7 to 5 μm. With the use of the two input-port and one output-port configurations, it was found that real-time optical subtraction could generate 80% background-noise-free spectra. When the spectrometers were operated in the one input-port and two o

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Kuwałek, Piotr. "Selective Identification and Localization of Voltage Fluctuation Sources in Power Grids." Energies 14, no. 20 (2021): 6585. http://dx.doi.org/10.3390/en14206585.

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The current study presents a novel approach to the selective identification and localization of voltage fluctuation sources in power grids, considering individual disturbing loads changing their state with a frequency of up to 150Hz. The implementation of the proposed approach in the existing infrastructure of smart metering allows for the identification and localization of the individual sources of disturbances in real time. The proposed approach first performs the estimation of the modulation signal using a carrier signal estimator, which allows for a modulation signal with a frequency great

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17

Yang, Ying Zhen, Chen Cui, Huan Wang, and Yi Biao Sun. "Multi-Period Discrete-Time Repetitive Control for Permanent Magnet Linear Synchronous Motor." Advanced Materials Research 588-589 (November 2012): 1644–49. http://dx.doi.org/10.4028/www.scientific.net/amr.588-589.1644.

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While tracking the periodic input signal, the position-dependent periodic thrust ripple caused by ending effect, load disturbance and the friction of the permanent magnet linear synchronous motor (PMLSM) will reduce the servo performance of the system. Especially when the periods of the reference input signal and thrust fluctuation interference signal are not synchronous, the precision of periodic signal tracked by the servo system is reduced, which lead to the reduction of the servo system’s periodic signal tracking precision. Therefore, a multi-period discrete repetitive controller using two

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18

Jia, Wang, Mingjun Diao, Lei Jiang, and Guibing Huang. "Fluctuating Characteristics of the Stilling Basin with a Negative Step Based on Hilbert-Huang Transform." Water 13, no. 19 (2021): 2673. http://dx.doi.org/10.3390/w13192673.

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The violent fluctuation of hydrodynamic pressure in stilling basins is an important factor threatening the safety of the bottom plates of stilling basins, and plays an important role in the safe operation of stilling basins. In order to deeply understand the fluctuating characteristics of stilling basins, the fluctuating pressure signal of a stilling basin bottom plate is processed by the Hilbert-Huang transform method through a hydraulic model test. In this paper, three signal decomposition methods are used to decompose the pulsating pressure signal. A Hilbert transform is used to select the

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19

Du, Yuxin, Hongzhong Lu, Zhifeng Yao, Ran Tao, Ruofu Xiao, and Fujun Wang. "Prediction of Pressure Fluctuation of Double-Suction Centrifugal Pump in Different Cavitation Conditions based on EMD-GRU." Journal of Physics: Conference Series 2854, no. 1 (2024): 012009. http://dx.doi.org/10.1088/1742-6596/2854/1/012009.

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Abstract The double-suction centrifugal pumps play a crucial role in various applications such as in irrigation-drainage projects, water diversion projects, and urban water supply and drainage projects. The pressure fluctuation is one of the crucial parameters for assessing the operational stability of pump. The pressure fluctuation exhibits distinct characteristics in various cavitation conditions. A pressure fluctuation prediction method based on Empirical Mode Decomposition (EMD) and Gated Recurrent Unit (GRU) is proposed in this paper. The model enables accurate forecasting of pressure flu

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20

Boiko, Juliy, Lesya Karpova, Oleksander Eromenko, and Yevhen Havrylko. "Evaluation of phase-frequency instability when processing complex radar signals." International Journal of Electrical and Computer Engineering (IJECE) 10, no. 4 (2020): 4226. http://dx.doi.org/10.11591/ijece.v10i4.pp4226-4236.

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A new radar system for digital signal processing before detection is proposed. These are the guidelines for selecting an intermediate frequency for signal processing. The features of signal processing in the case of echo-signal selection by the features of the correlation properties of their complex bypass are described. This paper presents the study of ambiguity function (AF) when processing complex radar signals. In this work, the AF synthesis was performed considering non-determined components and the presence of phase-frequency instability. The received result enhances the potentials for d

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Juliy, Boiko, Karpova Lesya, Eromenko Oleksander, and Havrylko Yevhen. "Evaluation of phase-frequency instability when processing complex radar signals." International Journal of Electrical and Computer Engineering (IJECE) 10, no. 4 (2020): 4226–36. https://doi.org/10.11591/ijece.v10i4.pp4226-4236.

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A new radar system for digital signal processing before detection is proposed. These are the guidelines for selecting an intermediate frequency for signal processing. The features of signal processing in the case of echo-signal selection by the features of the correlation properties of their complex bypass are described. This paper presents the study of ambiguity function (AF) when processing complex radar signals. In this work, the AF synthesis was performed considering non-determined components and the presence of phase-frequency instability. The received result enhances the potentials for d

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Hwang, Hwanwoong, Jae-Han Lim, Ji-Hoon Yun, and Byung Jeong. "Pattern-Based Decoding for Wi-Fi Backscatter Communication of Passive Sensors." Sensors 19, no. 5 (2019): 1157. http://dx.doi.org/10.3390/s19051157.

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Ambient backscatter communication enables passive sensors to convey sensing data on ambient RF signals in the air at ultralow power consumption. To extract data bits from such signals, threshold-based decoding has generally been considered, but suffers against Wi-Fi signals due to severe fluctuation of OFDM signals. In this paper, we propose a pattern-matching-based decoding algorithm for Wi-Fi backscatter communications. The key idea is the identification of unique patterns of signal samples that arise from the inevitable smoothing of Wi-Fi signals to filter out noisy fluctuation. We provide

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Mingesz, R., G. Vadai, and Z. Gingl. "Power Spectral Density Estimation for Wireless Fluctuation Enhanced Gas Sensor Nodes." Fluctuation and Noise Letters 13, no. 02 (2014): 1450011. http://dx.doi.org/10.1142/s0219477514500114.

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Fluctuation enhanced sensing (FES) is a promising method to improve the selectivity and sensitivity of semiconductor and nanotechnology gas sensors. Most measurement setups include high cost signal conditioning and data acquisition units as well as intensive data processing. However, there are attempts to reduce the cost and energy consumption of the hardware and to find efficient processing methods for low cost wireless solutions. In this paper, we propose highly efficient signal processing methods to analyze the power spectral density of fluctuations. These support the development of ultra-l

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GHOSH, DIPAK, ARGHA DEB, SRIMONTI DUTTA, ROSALIMA SENGUPTA, and SHUKLA SAMANTA. "MULTIFRACTALITY OF RADON CONCENTRATION FLUCTUATION IN EARTHQUAKE RELATED SIGNAL." Fractals 20, no. 01 (2012): 33–39. http://dx.doi.org/10.1142/s0218348x1250003x.

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Radon anomaly acts as a precursor to seismic events. Hence the fluctuation pattern of time series of radon bears a lot of significance. Multifractal detrended fluctuation analysis (MFDFA) has been applied successfully in past to various geo-electrical signals. The time series of earthquake related radon signal of duration three years (November 2005–November 2008) obtained from our experiment performed at Kolkata, India was analyzed in the framework of MFDFA. The study revealed that the fluctuation of radon concentration is multifractal in nature.

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Hang, Jiayu, Xizhao Zhou, and Jiawen Wang. "A Dynamic Control Method for Signalized Intersections Using the Flow Fluctuation Amplitude." Discrete Dynamics in Nature and Society 2020 (October 18, 2020): 1–10. http://dx.doi.org/10.1155/2020/2037248.

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Intersections are a vital component of the urban road network. Their use is essential for traffic efficiency and operational stability. In this paper, a dynamic control method for two-phase signal control intersection is proposed by using the intercycle flow standard deviation. This technique can dynamically assign weights to different control goals of traffic efficiency and operational stability. For intersections with large flow fluctuation amplitudes, greater weight is given to the control goal of operational stability to reduce the sensitivity of the signal control on flow fluctuation. For

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Pakarzadeh, H., M. Bagheri, and A. Keshavarz. "Designing one-pump fiber optical parametric amplifiers for an insensitive amplification to dispersion fluctuations." Journal of Nonlinear Optical Physics & Materials 23, no. 02 (2014): 1450023. http://dx.doi.org/10.1142/s0218863514500234.

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Small-signal gain spectrum of one-pump fiber optical parametric amplifiers (1-P FOPAs) is investigated in the presence of dispersion fluctuations. By assuming the dispersion fluctuations along the fiber as a stochastic process and using the matrix approach, the full gain spectrum of 1-P FOPAs is simulated. We have examined the gain spectrum of 1-P FOPAs for a wide range of fluctuation parameters, and it is shown for the first time that there are two specific wavelengths at which the dispersion fluctuations play no role. Analytical formulas are also presented to design 1-P FOPAs for amplifying

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Doho, Hirotaka, Haruhiko Nishimura, and Sou Nobukawa. "Dynamic Pattern Recognition Model Based on Neural Network Response to Signal Fluctuation." Journal of Advanced Computational Intelligence and Intelligent Informatics 27, no. 1 (2023): 44–53. http://dx.doi.org/10.20965/jaciii.2023.p0044.

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We have proposed a model of dynamic retrieval in associative memory based on temporal input/output correlations under a stimulus-response open scheme of neural networks. This mechanism is different from that of the conventional stationary Hopfield model in which the input signal is used only as information for the initial state of the network. Building upon the fundamental properties of the proposed model, in this paper, we newly evaluate the dependence of identification performance on the signal fluctuation level and on the number of stored patterns by introducing an accuracy rate for known (

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JOU, LIANG-DER. "MAGNETIC RESONANCE SIGNAL LOSS IN TURBULENT SHEAR FLOW." Biomedical Engineering: Applications, Basis and Communications 14, no. 01 (2002): 1–11. http://dx.doi.org/10.4015/s1016237202000024.

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NMR signal loss due to turbulent shear flow is discussed, and a general expression for the phase fluctuation is derived. In the presence of flow shear, the velocity fluctuation perpendicular to the direction of magnetic gradient and the Reynolds stress can cause loss of MR signal Most of signal loss results from the boundary layer, where the flow shear is strong in turbulent pipe flaw, Half the signal loss within the mixing layer distal to a moderate stenosis is caused by the velocity fluctuation in the direction of magnetic gradient, while the remaining results from the velocity, fluctuation

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Wang, Weiyu, Qijuan Chen, Xing Liang, Xuhui Yue, and Jinzhou Dou. "A Novel Multidimensional Frequency Band Energy Ratio Analysis Method for the Pressure Fluctuation of Francis Turbine." Mathematical Problems in Engineering 2018 (2018): 1–10. http://dx.doi.org/10.1155/2018/3494785.

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The pressure fluctuation has multiple influence on the steady operation of Francis turbine, and the impact degree varies with the operation condition. In this paper, for the analysis of pressure fluctuation in the Francis turbine, a novel feature extraction method of multidimensional frequency bands energy ratio is proposed based on Hilbert Huang Transform (HHT). Firstly, the pressure fluctuation signal is decomposed into intrinsic mode functions (IMFs) by EEMD. Secondly, the Hilbert marginal spectrum is utilized to analyze the frequency characteristics of IMFs. Then, according to the inner fr

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Gurvich, Alexander Sergeevich, and Victor Alexeevich Kulikov. "Impact of pitch angle fluctuations on airborne lidar forward sensing along the flight direction." Atmospheric Measurement Techniques 10, no. 10 (2017): 3851–64. http://dx.doi.org/10.5194/amt-10-3851-2017.

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Abstract. Airborne lidar forward sensing along the flight direction can serve for notification of clear air turbulence (CAT) and help to prevent injuries or fatal air accidents. The validation of this concept was presented in the framework of the DELICAT (DEmonstration of LIdar-based CAT detection) project. However, the strong variations in signal level, which were observed during the DELICAT measurements but not explained, sometimes indicated the need of a better understanding the observational errors due to geometrical factors. In this paper, we discuss possible error sources pertinent to th

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Xu, Ya Min. "Particle Size Measurements Using a New Signal Processing Method." Applied Mechanics and Materials 239-240 (December 2012): 1011–17. http://dx.doi.org/10.4028/www.scientific.net/amm.239-240.1011.

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Transmission fluctuation spectrometry (TFS) is a new method for particle analysis based on the statistical fluctuations of a transmission signal. With simple optical arrangement and easy operation, the method can be applied to real-time, online measurements. The transmission signal with fluctuations are analyzed by using 1st order band-pass filters, and the experimental data in the frequency domain are obtained. The particle size distribution (PSD) and particle concentration are extracted from the experimental data with the modifed Chahine interations. It is found that the measurements using b

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Zhao, Wu, and Dan Huang. "Experiment and Test Signal Analysis Based on Speed Fluctuation of Torsional Vibration of Large-Scale Rotary Machinery." Advanced Materials Research 346 (September 2011): 501–7. http://dx.doi.org/10.4028/www.scientific.net/amr.346.501.

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A new mode of fault monitoring and controling methods on rotating speed fluctuation was proposed in this study. Torsional vibration model and identification equation of speed fluctuation of large-scale rotary machinery was established based on a two-mass motor driving model. Tachogenerator was adopted to measure speed fluctuation in torsional vibration experiment of large-scale rotary machinery. According to the short time fourier transforms method, the non-steady cyclical or quasi-cyclical characteristics signal of rotating speed fluctuation on elastic shafts were transformed into steady sign

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Gao, Wenning, Fuzhan Yue, Zhenghuan Xia, et al. "Dual-Frequency Signal Enhancement Method of Moving Target Echoes for GNSS-S Radar." Remote Sensing 15, no. 18 (2023): 4519. http://dx.doi.org/10.3390/rs15184519.

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The GNSS-S radar utilizes the signals of a global navigation satellite system (GNSS) to carry out target detection. Due to the very low power of GNSS signals, long-term accumulation is needed to improve the gain of the echo signals. However, when it is used for moving object detection, the random movement of the target will cause residual Doppler frequency after the echoes are correlated and compressed through the direct signal. The residual Doppler frequency will cause two problems: on the one hand, the signal coherence will deteriorate, affecting the coherent accumulation gain; on the other

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Iida, Mirai, Iliana Marinova, and Yoshifuru Saito. "Frequency fluctuation signal processing and its application to the Barkhausen signals." International Journal of Applied Electromagnetics and Mechanics 52, no. 1-2 (2016): 371–79. http://dx.doi.org/10.3233/jae-162132.

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Chen, Yinsheng, Zichen Yuan, Jiahui Chen, and Kun Sun. "A Novel Fault Diagnosis Method for Rolling Bearing Based on Hierarchical Refined Composite Multiscale Fluctuation-Based Dispersion Entropy and PSO-ELM." Entropy 24, no. 11 (2022): 1517. http://dx.doi.org/10.3390/e24111517.

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This paper proposes a novel fault diagnosis method for rolling bearing based on hierarchical refined composite multiscale fluctuation-based dispersion entropy (HRCMFDE) and particle swarm optimization-based extreme learning machine (PSO-ELM). First, HRCMFDE is used to extract fault features in the vibration signal at different time scales. By introducing the hierarchical theory algorithm into the vibration signal decomposition process, the problem of missing high-frequency signals in the coarse-grained process is solved. Fluctuation-based dispersion entropy (FDE) has the characteristics of ins

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Morozov, Yu V., M. A. Rajfeld, and A. A. Spektor. "NOISE AND TARGET SIGNALS SIMULATION IN PASSIVE SEISMIC LOCATION SYSTEMS." Issues of radio electronics, no. 4 (April 20, 2018): 73–78. http://dx.doi.org/10.21778/2218-5453-2018-4-73-78.

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The paper proposes the model of a person seismic signal with noise for the investigation of passive seismic location system characteristics. The known models based on Gabor and Berlage pulses have been analyzed. These models are not able wholly to consider statistical properties of seismic signals. The proposed model is based on almost cyclic character of seismic signals, Gauss character of fluctuations inside a pulse, random amplitude change from pulse to pulse and relatively small fluctuation of separate pulses positions. The simulation procedure consists of passing the white noise through a

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Ye, Lyuzhou, Jérémy R. Rouxel, Daeheum Cho, and Shaul Mukamel. "Imaging electron-density fluctuations by multidimensional X-ray photon-coincidence diffraction." Proceedings of the National Academy of Sciences 116, no. 2 (2018): 395–400. http://dx.doi.org/10.1073/pnas.1816730116.

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The ultrafast spontaneous electron-density fluctuation dynamics in molecules is studied theoretically by off-resonant multiple X-ray diffraction events. The time- and wavevector-resolved photon-coincidence signals give an image of electron-density fluctuations expressed through the four-point correlation function of the charge density in momentum space. A Fourier transform of the signal provides a real-space image of the multipoint charge-density correlation functions, which reveal snapshots of the evolving electron density in between the diffraction events. The proposed technique is illustrat

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Bracalari, Mauro, and Ettore Salusti. "On a nonlinear autoregressive method applied to geophysical signals." GEOPHYSICS 59, no. 8 (1994): 1270–77. http://dx.doi.org/10.1190/1.1443684.

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A nonlinear second‐order autoregressive analysis of time varying signals leads to simple inhomogeneous linear algebraic equations. This method was applied to the analysis of three types of geophysical signals: the fluctuation of sea level at Venice (Italy), “harmonic tremors” at Stromboli (Eolian Islands), and the earth’s crustal motion at L’Aquila (Italy). For more regular motions (earth’s crustal motion), linear and nonlinear methods give essentially equivalent results. Compared to the customary linear autoregressive method, our method more accurately predicts nonlinearities whenever there i

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Anandan, Meena, Pandiyarasan Veluswamy, and Rohini Palanisamy. "Quantitative ECG based emotion state recognition using Detrended Fluctuation Analysis." Current Directions in Biomedical Engineering 9, no. 1 (2023): 702–5. http://dx.doi.org/10.1515/cdbme-2023-1176.

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Abstract Wearable emotion recogniton system is essential in identifying mental health disorders by early detection and continuous monitoring of human emotions to provide proper treatment care. Electrocardiogram (ECG) signals can be used for emotion recognition for its noninvasiveness and easy usability. In this study, Detrended Fluctuation Analysis (DFA) and Extreme Gradient Boost (XG Boost) classifier is used to classify the scary and boring emotion from the ECG signals. For this, ECG signal corresponding to these emotions are obtained from public database. The preprocessing is performed by a

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Morgulis, Andrey B., and Konstantin I. Ilin. "Drift, Stabilization and Destabilization of Patlak-Keller-Seegel Systems Due to a Short-Wave External Signal." UNIVERSITY NEWS. NORTH-CAUCASIAN REGION. NATURAL SCIENCES SERIES, no. 4 (208) (December 23, 2020): 36–48. http://dx.doi.org/10.18522/1026-2237-2020-4-36-48.

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In this article, we explore a community of two species placed on the inhomogeneous environment. We assume interspecific taxis as well as responding to the environmental fluctuations by tactic movement. We study the effect of the small-scale environmental fluctuations on the large-scale dynamics of the community following the line of Kapitza&#x27;s theory of the upside-down pendulum. It turns out that, the only conductor of the effect of the fluctuations on the large-scale patterns is some drift of species. When the fluctuation takes the form of a travelling wave, there exist the quasi-equi

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Xiao, Huifang, Xiaojun Zhou, and Yimin Shao. "Application of an improved dynamic time synchronous averaging method for fault diagnosis in conditions of speed fluctuation and no tachometer." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, no. 14 (2015): 2517–31. http://dx.doi.org/10.1177/0954406215597956.

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Time synchronous averaging has been widely used for machinery fault diagnosis. However, it cannot reveal signal characteristics accurately in conditions of speed fluctuation and no tachometer due to the phase accumulation error. In this paper, an improved dynamic-time synchronous averaging method is proposed to extract the periodic feature signal from the fluctuated vibration signal for fault detection when no tachometer signal is available. In this method, empirical mode decomposition, dynamic time warping, and time synchronous averaging are performed on gear vibration signals to detect fault

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Borysenko, Anatoliy, Oleksandr Yenikieiev, Dmitry Zakharenkov, Ihor Zykov, and Oleksandr Melnykov. "ALGORITHMIC PROVISION OF MONITORING OF IDENTITY OF CYLINDER POWERS OF POWER UNITS ON THE BASIS OF PROCESSING OF DIRECT INDIRECT DATA." Bulletin of the National Technical University «KhPI» Series: New solutions in modern technologies, no. 1(11) (May 18, 2022): 3–11. http://dx.doi.org/10.20998/2413-4295.2022.01.01.

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A frequency-modulated instantaneous crankshaft speed signal is proposed as input information for monitoring the identity of the cylinder power of an internal combustion engine. Algorithmic software is based on solving a predefined system of linear algebraic equations with optimization of the solution based on the least-squares method. Frequency and time methods of signal measurement research are investigated. In the temporal representation, the system of algebraic equations is the balance between the values of the fluctuation signal of the first mass at specific points in time and the sum of t

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Li, Jiming, Yongji Sun, and Xuezhen Cheng. "Removal of Dust Microelectric Signal Based on Empirical Mode Decomposition and Multifractal Detrended Fluctuation Analysis." Computational Intelligence and Neuroscience 2021 (August 6, 2021): 1–21. http://dx.doi.org/10.1155/2021/5468514.

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Microcharge induction has recently been applied as a dust detection method. However, in complex environments, the detection device can be seriously polluted by noise. To improve the quality of the measured signal, the characteristics of both the signal and the noise should be analyzed so as to determine an effective noise removal method. Traditional removal methods mostly deal with specific noise signals, and it is difficult to consider the correlation of measured signals between adjacent time periods. To overcome this shortcoming, we describe a method in which wavelet decomposition is applied

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Zhang, Yong, Guangjun He, and Guangjian Li. "Automatic Electrical System Fault Diagnosis Using a Fuzzy Inference System and Wavelet Transform." Processes 11, no. 8 (2023): 2231. http://dx.doi.org/10.3390/pr11082231.

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Electrical systems consist of varied components that are used for power distribution, supply, and transfer. During transmission, component failures occur as a result of signal interruptions and peak utilization. Therefore, fault diagnosis should be performed to prevent fluctuations in the power distribution. This article proposes a fluctuation-reducing fault diagnosis method (FRFDM) for use in power distribution networks. The designed method employs fuzzy linear inferences to identify fluctuations in electrical signals that occur due to peak load demand and signal interruptions. The fuzzy proc

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KAWAZOE, Jun, and Yoshifuru SAITO. "Analysis of Frequency Fluctuation Using Barkhausen Signal." Journal of the Magnetics Society of Japan 37, no. 4 (2013): 320–26. http://dx.doi.org/10.3379/msjmag.1306r001.

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Tang, Y. S. "Characterization of head stability induced signal fluctuation." IEEE Transactions on Magnetics 26, no. 5 (1990): 2466–68. http://dx.doi.org/10.1109/20.104766.

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Wen, Shaobo, Yipeng Gong, Xiufeng Mu, Sufang Zhao, and Chuanjun Wang. "Optimal Configuration of Flywheel–Battery Hybrid Energy Storage System for Smoothing Wind–Solar Power Generating Fluctuation." Energies 18, no. 8 (2025): 2055. https://doi.org/10.3390/en18082055.

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The integration of energy storage systems is an effective solution to grid fluctuations caused by renewable energy sources such as wind power and solar power. This paper proposes a hybrid energy storage system (HESS) capacity optimization method combining flywheel and battery energy storage. Firstly, improved complete ensemble empirical mode decomposition with adaptive noise (ICEEMDAN) is employed to decompose the original wind–solar power signal into a grid-connected signal and a leveling command signal. Low-pass filtering is then applied to separate the leveling command signal by frequency a

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Li, Zhaoxi, Yaan Li, and Kai Zhang. "A Feature Extraction Method of Ship-Radiated Noise Based on Fluctuation-Based Dispersion Entropy and Intrinsic Time-Scale Decomposition." Entropy 21, no. 7 (2019): 693. http://dx.doi.org/10.3390/e21070693.

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To improve the feature extraction of ship-radiated noise in a complex ocean environment, fluctuation-based dispersion entropy is used to extract the features of ten types of ship-radiated noise. Since fluctuation-based dispersion entropy only analyzes the ship-radiated noise signal in single scale and it cannot distinguish different types of ship-radiated noise effectively, a new method of ship-radiated noise feature extraction is proposed based on fluctuation-based dispersion entropy (FDispEn) and intrinsic time-scale decomposition (ITD). Firstly, ten types of ship-radiated noise signals are

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Liu, Jiamin, Shuai Meng, Xintao Zhou, and Lichen Gu. "A Hydraulic Axial Piston Pump Fault Diagnosis Based on Instantaneous Angular Speed under Non-Stationary Conditions." Lubricants 11, no. 9 (2023): 406. http://dx.doi.org/10.3390/lubricants11090406.

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Due to the intense noise interference in hydraulic systems, it is extremely difficult to detect component faults through vibration signals. Diagnostic performance is also constrained by highly time-varying and non-stationary operating conditions. This study proposes to use instantaneous angular speed (IAS) signals that are both operational and state parameters as sources of information. Firstly, the instantaneous angular speed fluctuation (IASF) of a piston pump is analyzed theoretically, and it is concluded that its fluctuating components contain the health status information of the component

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Kan, Valery, Michael E. Gorbunov, and Viktoria F. Sofieva. "Fluctuations of radio occultation signals in sounding the Earth's atmosphere." Atmospheric Measurement Techniques 11, no. 2 (2018): 663–80. http://dx.doi.org/10.5194/amt-11-663-2018.

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Abstract. We discuss the relationships that link the observed fluctuation spectra of the amplitude and phase of signals used for the radio occultation sounding of the Earth's atmosphere, with the spectra of atmospheric inhomogeneities. Our analysis employs the approximation of the phase screen and of weak fluctuations. We make our estimates for the following characteristic inhomogeneity types: (1) the isotropic Kolmogorov turbulence and (2) the anisotropic saturated internal gravity waves. We obtain the expressions for the variances of the amplitude and phase fluctuations of radio occultation

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