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Journal articles on the topic 'Time and Frequency Plot (TAFPLOT)'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

Peng, Fu Min, and Bin Fang. "Stabilizing Gain Regions of PID Controller for Time Delay Systems." Applied Mechanics and Materials 313-314 (March 2013): 432–37. http://dx.doi.org/10.4028/www.scientific.net/amm.313-314.432.

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Based on the inverse Nyquist plot, this paper proposes a method to determine stabilizing gain regions of PID controller for time delay systems. According to the frequency characteristic of the inverse Nyquist plot, it is confirmed that the frequency range is used for stability analysis, and the abscissas of two kind key points are obtained in this range. PID gain is divided into several regions by abscissas of key points. Using an inference and two theorems presented in the paper, the stabilizing PID gain regions are determined by the number of intersections of the inverse Nyquist plot and the

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2

Piedad, Eduardo Jr, Yu-Tung Chen, Hong-Chan Chang, and Cheng-Chien Kuo. "Frequency Occurrence Plot-Based Convolutional Neural Network for Motor Fault Diagnosis." Electronics 9, no. 10 (October 18, 2020): 1711. http://dx.doi.org/10.3390/electronics9101711.

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A novel motor fault diagnosis using only motor current signature is developed using a frequency occurrence plot-based convolutional neural network (FOP-CNN). In this study, a healthy motor and four identical motors with synthetically applied fault conditions—bearing axis deviation, stator coil inter-turn short circuiting, a broken rotor strip, and outer bearing ring damage—are tested. A set of 150 three-second sampling stator current signals from each motor fault condition are taken under five artificial coupling loads (0, 25%, 50%, 75% and 100%). The sampling signals are collected and process

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Yusof, M. F. M., Mahadzir, Mohd Fairusham Ghazali, and Mohd Rafiqul Islam. "Analysis of an Air Borne Acoustic Signatures from Welding Process Using Empirical Mode Decomposition." Advanced Materials Research 889-890 (February 2014): 770–75. http://dx.doi.org/10.4028/www.scientific.net/amr.889-890.770.

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This work present the application of Empirical Mode Decomposition (EMD) to analyze the air borne acoustic signatures commenced during welding process. In order to achieve goals, bead-on plate welding was done onto the carbon steel specimen using Metal Inert Gas Welding. At the same moment, the microphone with operating frequency of 31.5 Hz to 8 kHz used to collect air borne acoustic signatures. In analysis part, Empirical Mode Decomposition has been applied to the acoustic signals and the selected Intrinsic Mode Function (IMF) was presented in frequency-distance plot using spectrogram. Based o

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Carrasco, M. J. Gaitán, R. González, S. "Correlation among Poincare´plot indexes and time and frequency domain measures of heart rate variability." Journal of Medical Engineering & Technology 25, no. 6 (January 2001): 240–48. http://dx.doi.org/10.1080/03091900110086651.

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Chen, Shih Tsung, Chia Yi Chou, and Li Ho Tseng. "Recurrence Plot Analysis of HRV for Exposure to Low-Frequency Noise." Advanced Materials Research 1044-1045 (October 2014): 1251–57. http://dx.doi.org/10.4028/www.scientific.net/amr.1044-1045.1251.

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Previous studies have indicated that the chronic effects of exposure to low-frequency noise causes annoyance. However, during the past two decades, most studies have employed questionnaires to characterize the effects of noise on psychosomatic responses. This study investigated cardiovascular activity changes in exposure to low-frequency noise for various noise intensities by using recurrence plot analysis of heart rate variability (HRV) estimation. The authors hypothesized that distinct noise intensities affect cardiovascular activity, which would be reflected in the HRV and recurrence quanti

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Georgieva-Tsaneva, Galya, Evgeniya Gospodinova, Mitko Gospodinov, and Krasimir Cheshmedzhiev. "Cardio-Diagnostic Assisting Computer System." Diagnostics 10, no. 5 (May 19, 2020): 322. http://dx.doi.org/10.3390/diagnostics10050322.

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The mathematical analysis and the assessment of heart rate variability (HRV) based on computer systems can assist the diagnostic process with determining the cardiac status of patients. The new cardio-diagnostic assisting computer system created uses the classic Time-Domain, Frequency-Domain, and Time-Frequency analysis indices, as well as the nonlinear methods (Poincaré plot, Recurrence plot, Hurst R/S method, Detrended Fluctuation Analysis (DFA), Multi-Fractal DFA, Approximate Entropy and Sample Entropy). To test the feasibility of the software developed, 24-hour Holter recordings of four gr

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Brennan, Michael, Marimuthu Palaniswami, and Peter Kamen. "Poincaré plot interpretation using a physiological model of HRV based on a network of oscillators." American Journal of Physiology-Heart and Circulatory Physiology 283, no. 5 (November 1, 2002): H1873—H1886. http://dx.doi.org/10.1152/ajpheart.00405.2000.

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In this paper, we develop a physiological oscillator model of which the output mimics the shape of the R-R interval Poincaré plot. To validate the model, simulations of various nervous conditions are compared with heart rate variability (HRV) data obtained from subjects under each prescribed condition. For a variety of sympathovagal balances, our model generates Poincaréplots that undergo alterations strongly resembling those of actual R-R intervals. By exploiting the oscillator basis of our model, we detail the way that low- and high-frequency modulation of the sinus node translates into R-R

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8

Alqamari, Muhammad, Chairani Hanum, and Hamidah Hanum. "PERTUMBUHAN DAN HASIL TIGA VARIETAS CABAI MERAH (Capsicum annuum L.) DENGAN APLIKASI KALIUM SULFAT." Jurnal Pertanian Tropik 3, no. 3 (December 1, 2016): 249–55. http://dx.doi.org/10.32734/jpt.v3i3.2984.

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This research was conducted in the experimental field of Agricultural Faculty of North Sumatra Muhammadiyah University with a height of ± 27 meters dpl, held in july - nov 2012. This study aims to determine the best dose frequency of k2so4 on growth and the result of red chili varieties. This research was conducted using the split plot design with two factors; the varieties factor as the main plot with 3 kinds of varieties, named, V1 = TM 999, V2 = Lado, V3 = Landung; and the dose and frequency factors of k2so4 as subplot with 10 stages of treatment which is: K0 = 0, dose = 1.5 g / liter frequ

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Marino, Stefano, and Arturo Alvino. "Detection of Spatial and Temporal Variability of Wheat Cultivars by High-Resolution Vegetation Indices." Agronomy 9, no. 5 (May 5, 2019): 226. http://dx.doi.org/10.3390/agronomy9050226.

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An on-farm research study was carried out on two small-plots cultivated with two cultivars of durum wheat (Odisseo and Ariosto). The paper presents a theoretical approach for investigating frequency vegetation indices (VIs) in different areas of the experimental plot for early detection of agronomic spatial variability. Four flights were carried out with an unmanned aerial vehicle (UAV) to calculate high-resolution normalized difference vegetation index (NDVI) and optimized soil-adjusted vegetation index (OSAVI) images. Ground agronomic data (biomass, leaf area index (LAI), spikes, plant heigh

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10

Zhan, Wen Lian, and Jing Fang Wang. "Voice Activity Detection Based on Nonlinear Processing Techniques." Applied Mechanics and Materials 198-199 (September 2012): 1560–66. http://dx.doi.org/10.4028/www.scientific.net/amm.198-199.1560.

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Hilbert-Huang transform is developed in recent years dealing with nonlinear, non-stationary signal analysis of the complete local time-frequency method, recurrence plot method is a recursive nonlinear dynamic behavior of time series method of reconstruction. In this paper, Hilbert-Huang Transform empirical mode decomposition (EMD) and the recurrence plot (RP) method, a new voice activity detection algorithm. Firstly, through the speech and noise based on the empirical mode decomposition and multi-scale features of the different intrinsic mode function (IMF) on a time scale filtering and nonlin

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11

Şenol, Bilal, and Uğur Demiroğlu. "Fractional order proportional derivative control for first order plus time delay plants: achieving phase and gain specifications simultaneously." Transactions of the Institute of Measurement and Control 41, no. 15 (June 25, 2019): 4358–69. http://dx.doi.org/10.1177/0142331219857397.

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The aim of the method in this paper is to achieve desired gain and phase specifications for robustness and performance of first order plus time delay plants. The previously proposed method “frequency frame”, implemented for tuning fractional order proportional integral controllers, is applied on such plants controlled with a fractional order proportional derivative controller. Four specifications of gain and phase are considered in the Bode plot inspired from an ideal system. The frame is drawn enclosing the magnitude and phase curves limited by gain and phase crossover frequencies. Then, the

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Kamen, Peter Walter, Henry Krum, and Andrew Maxwell Tonkin. "Poincaré Plot of Heart Rate Variability Allows Quantitative Display of Parasympathetic Nervous Activity in Humans." Clinical Science 91, no. 2 (August 1, 1996): 201–8. http://dx.doi.org/10.1042/cs0910201.

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1. Time domain summary statistics and frequency domain parameters can be used to measure heart rate variability. More recently, qualitative methods including the Poincaré plot have been used to evaluate heart rate variability. The aim of this study was to validate a novel method of quantitative analysis of the Poincaré plot using conventional statistical techniques. 2. Beat-to-beat heart rate variability was measured over a relatively short period of time (10–20 min) in 12 healthy subjects aged between 20 and 40 years (mean 30 ± 7 years) during (i) supine rest, (ii) head-up tilt (sympathetic a

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Wang, Lina, Chengdong Wang, and Yong Chen. "A Fast Three-Dimensional Display Method for Time-Frequency Spectrogram Used in Embedded Fault Diagnosis Devices." Applied Sciences 8, no. 10 (October 15, 2018): 1930. http://dx.doi.org/10.3390/app8101930.

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Time-frequency analysis is usually used to reveal the appearance of different frequency components varying with time, in signals, of which time-frequency spectrogram is an important visual tool to display the information. The Mesh Surface Generation (MSG) algorithm is widely used in three-dimensional (3D) modeling. Removing hidden lines from the mesh plot is an essential process that produces explicit depth information. In this paper, a fast and effective method has been proposed for a time-frequency Spectrogram Mesh Surface Generation (SMSG) display, especially, based on the painter’s algorit

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14

Shi, Ping, Ying Chen, Ming-Ming Guo, and Hong-Liu Yu. "ACUTE EFFECTS OF ALCOHOL ON HEART RATE VARIABILITY: TIME-RELATED CHANGES AND GENDER DIFFERENCE." Biomedical Engineering: Applications, Basis and Communications 26, no. 03 (March 17, 2014): 1450048. http://dx.doi.org/10.4015/s1016237214500483.

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Objectives: Alcohol consumption is associated with a broad array of physiologic and behavioral effects including changes in cardiac autonomic activity. In the present study, time-related acute effects of alcohol have been characterized and compared between genders. Methods: A total of 30 healthy subjects (15 males and 15 females) were enrolled in this study. The red wine was given to each subject at a dosage of 0.27 g of pure ethanol per kilogram of body weight. 5-min electrocardiograms (ECGs) were collected before (BR) and at 15 min (P15), 30 min (P30), 45 min (P45) and 60 min (P60) after alc

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15

Pitsik, Elena, and Nikita Frolov. "Recurrence plot structures reflect motor-related EEG pattern." Cybernetics and Physics, Volume 8, 2019, Number 4 (December 30, 2019): 282–86. http://dx.doi.org/10.35470/2226-4116-2019-8-4-282-286.

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Detection and classification of motor-related brain patterns from non-invasive electroencephalograms (EEGs) is challenging due to their non-stationarity and low signal-to-noise ratio and requires using advanced mathematical approaches. Traditionally applied methods such as time-frequency analysis and spatial filtering allow to quantify the main attribute of the motor-related brain activity – contralateral desynchronization of mu-band oscillations (8-13 Hz) in sensorimotor cortex – by measuring EEG signal’s amplitude, power spectral density, location etc. However, these features suffer from str

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NASRIN, RAHIMA, and A. H. BHUIYAN. "THERMAL AND AC ELECTRICAL PROPERTIES OF THIN FILMS PREPARED FROM n-BUTYL METHACRYLATE BY A CAPACITIVELY COUPLED PLASMA REACTOR." Surface Review and Letters 26, no. 02 (February 2019): 1850146. http://dx.doi.org/10.1142/s0218625x18501469.

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Plasma-polymerized thin films of n-butyl methacrylate (PPnBMA) have been deposited on to glass substrate in an aluminium/PPnBMA/aluminium configuration by a capacitively coupled glow discharge reactor. The field emission scanning electron microscope and atomic force microscope images of PPnBMA thin films showed a flat, uniform and continuous surface. With increasing deposition time the root mean square roughness of the PPnBMA thin films increases. The differential thermal analysis and thermogravimetric analysis demonstrated that PPnBMA was thermally stable up to about 476 and 500[Formula: see

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17

An, Li Qiong, D. S. Wang, Run Hua Fan, and Li Hua Dong. "Dielectric and Conduction Properties of Lu₃NbO₇ Transparent Ceramic." Materials Science Forum 898 (June 2017): 1681–85. http://dx.doi.org/10.4028/www.scientific.net/msf.898.1681.

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The dielectric response and electrical conduction of Lu3NbO7 transparent ceramic produced by spark plasma sintering were investigated. Lu3NbO7 transparent ceramic exhibited low frequency dielectric dispersion and a peak in dielectric loss, shifting to higher frequency at high temperatures. This indicated space charge polarization and broad relaxation time, confirmed by impedance and modulus spectra. The Nyquist plot shows the dominant grain effect in the electrical conduction. The AC conductivity of Lu3NbO7 transparent ceramic is 4.18×10-2 S m-1 at 1073 K, with an activation energy of 1.30 eV.

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18

George, Fabian Parsia, Istiaque Mannafee Shaikat, Prommy Sultana Ferdawoos Hossain, Mohammad Zavid Parvez, and Jia Uddin. "Recognition of emotional states using EEG signals based on time-frequency analysis and SVM classifier." International Journal of Electrical and Computer Engineering (IJECE) 9, no. 2 (April 1, 2019): 1012. http://dx.doi.org/10.11591/ijece.v9i2.pp1012-1020.

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The recognition of emotions is a vast significance and a high developing field of research in the recent years. The applications of emotion recognition have left an exceptional mark in various fields including education and research. Traditional approaches used facial expressions or voice intonation to detect emotions, however, facial gestures and spoken language can lead to biased and ambiguous results. This is why, researchers have started to use electroencephalogram (EEG) technique which is well defined method for emotion recognition. Some approaches used standard and pre-defined methods of

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19

Yuhang, Hu. "Multi-scale Order Recurrence Plot based deterministic analysis on Heart Rate Variability in Congestive Heart Failure Assessment." E3S Web of Conferences 271 (2021): 03063. http://dx.doi.org/10.1051/e3sconf/202127103063.

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Congestive heart failure (CHF) is a cardiovascular disease associated with the abnormal autonomic nervous system (ANS). Heart rate variability analysis (HRV) is the main method for the quantitative evaluation of autonomic nervous function. Common analytical methods of HRV include time domain, frequency domain, and nonlinear methods. However, these methods generally ignore the short-term volatility of heart rate and autonomic ganglion law. Therefore, this study proposes a new parameter to analyze heart rate variability-determination of a multi-scale order recurrence plot (MSORP_DET). This metho

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Nguyen-Huu, Thien-An, Van Thang Nguyen, Kyeon Hur, and Jae Woong Shim. "Coordinated Control of a Hybrid Energy Storage System for Improving the Capability of Frequency Regulation and State-of-Charge Management." Energies 13, no. 23 (November 29, 2020): 6304. http://dx.doi.org/10.3390/en13236304.

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The paper proposes a coordinated operation method of two independent storages for managing state-of-charge (SOC) and for providing ancillary service concerning frequency regulation (FR); furthermore, this article also introduces the power allocation scheme between two storages in consideration of the coverage of the frequency band for each storage along with the SOC management scheme of the supercapacitor and battery. We also provide a guideline for the storage sizing on the basis of the smoothing time constant. Additionally, we verify the advantage of the HESS in extending the lifetime of the

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Köhler, P., H. Fischer, J. Schmitt та G. Munhoven. "On the application and interpretation of Keeling plots in paleo climate research – deciphering δ<sup>13</sup>C of atmospheric CO<sub>2</sub> measured in ice cores". Biogeosciences 3, № 4 (15 листопада 2006): 539–56. http://dx.doi.org/10.5194/bg-3-539-2006.

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Abstract. The Keeling plot analysis is an interpretation method widely used in terrestrial carbon cycle research to quantify exchange processes of carbon between terrestrial reservoirs and the atmosphere. Here, we analyse measured data sets and artificial time series of the partial pressure of atmospheric carbon dioxide (pCO2) and of δ13C of CO2 over industrial and glacial/interglacial time scales and investigate to what extent the Keeling plot methodology can be applied to longer time scales. The artificial time series are simulation results of the global carbon cycle box model BICYCLE. The s

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22

Lee, Si Hyeock, Il Sung Moon, Jae Soon Kang, Sang Chul Shin, and Sang Gil Lee. "Rapid and accurate prediction of the frequencies of Bursaphelenchus xylophilus and B. mucronatus in mixed nematode samples using real-time species-specific PCR." Nematology 11, no. 2 (2009): 289–99. http://dx.doi.org/10.1163/156854109x429619.

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AbstractAccurate detection of Bursaphelenchus xylophilus and prediction of its frequency in crude nematode samples is often hindered by the coexistence of related nematode species, such as B. mucronatus, that are morphologically similar but non-pathogenic. To establish a detection system enabling determination of the relative frequencies of B. xylophilus and B. mucronatus from field nematode samples, we developed a real-time species-specific PCR (rtssPCR) protocol which targets the substantial sequence differences in the 5S rRNA marker gene between the two nematode species. Using standard DNA

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Shin, Ki Hong. "A New Signal Processing Technique to Estimate Velocity Dependent Dynamic Friction Coefficient." Key Engineering Materials 321-323 (October 2006): 1241–44. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.1241.

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In general, dynamic friction coefficient in a dry surface condition is dependent on the relative velocity between two sliding bodies. A conventional method of estimating the velocity dependent dynamic friction coefficient is time consuming and requires a special jig to measure the friction forces. In this paper, a new technique called the state space mapping method is proposed based on the nonlinear dynamics of a 1-DOF friction oscillator. One body is constructed as a single degree of freedom system and another body is formed as a moving base that may be built as a rotating disk or a horizonta

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Bourdim, Samia, Kamel Eddine Hemsas, and Youcef Harbouche. "Intelligent Diagnostic of Induction Machine for Faults Detection and Classification Using Wavelet and Fuzzy Inference." Applied Mechanics and Materials 789-790 (September 2015): 597–603. http://dx.doi.org/10.4028/www.scientific.net/amm.789-790.597.

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An intelligent diagnostic method based on 3-D plot continuous wavelet transform (3-D plot CWT) and fuzzy inference system is presented to investigate the detectability and classification of rotor broken bars faults in induction machine (IM) and to overcome the limitation of classical Fourier Transform (FT). This approach is successfully used with Motor Current Signature Analysis (MCSA) and suitable developed model of IM in healthy and faulty mode using Matlab environment. As first step we performed new results using 3-D plot CWT to extract the discriminating features. The features extracted fr

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Bourdim, Samia, Kamel Eddine Hemsas, Youcef Harbouche, and Rachid Abdssemed. "Intelligent Diagnostic of Induction Machine for Faults Detection and Classification Using Wavelet and Fuzzy Inference." Applied Mechanics and Materials 799-800 (October 2015): 964–70. http://dx.doi.org/10.4028/www.scientific.net/amm.799-800.964.

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An intelligent diagnostic method based on 3-D plot continuous wavelet transform (3-D plot CWT) and fuzzy inference system is presented to investigate the detectability and classification of rotor broken bars faults in induction machine (IM) and to overcome the limitation of classical Fourier Transform (FT). This approach is successfully used with Motor Current Signature Analysis (MCSA) and suitable developed model of IM in healthy and faulty mode using Matlab environment. As first step we performed new results using 3-D plot CWT to extract the discriminating features. The features extracted fr

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Yu, Wenfei. "Probing the X-ray Variability of X-ray Binaries." Symposium - International Astronomical Union 214 (2003): 236–39. http://dx.doi.org/10.1017/s0074180900194483.

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Kilohertz quasi-periodic oscillations (kHz QPOs) has been regarded as representing the Keplerian frequency at the inner disk edge in the neutron star X-ray binaries. The so-called “parallel tracks” on the plot of the kHz QPO frequency vs. X-ray flux in neutron star X-ray binaries, on the other hand, show the correlation between the kHz QPO frequency and the X-ray flux on time scales from hours to days. This is suspected as caused by the variations of the mass accretion rate through the accretion disk surrounding the neutron star. We show here that by comparing the correlation between the kHz Q

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Cawley, P., and L. G. Rigner. "Rapid Measurement of Modal Properties Using FFT Analyzers With Random Excitation." Journal of Vibration and Acoustics 108, no. 4 (October 1, 1986): 394–98. http://dx.doi.org/10.1115/1.3269361.

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The use of a Nyquist plot of the H2 (Syy/Sxy*) frequency response function estimates produced by an FFT based spectrum analyzer with random excitation to obtain modal amplitudes and hence modal constants has been investigated. It has been proved that, irrespective of the frequency resolution used, the H2 estimates always lie on the true modal circle so even at coarse frequency resolution, a circle fitted to these points gives accurate values of modal amplitude. The conventional H1 (Sxy/Sxx) estimates lie inside the true modal circle. Use of the H2 technique results in major savings in the test

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Hommadi, Ali Hassan, and Sabah Anwer Almasraf. "Water Retention Techniques under Crop’s Root Zone a Tool to Enhance Water Use Efficiency and Economic Water Productivity for Zucchini." Journal of Engineering 25, no. 6 (May 31, 2019): 44–52. http://dx.doi.org/10.31026/j.eng.2019.06.04.

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A new technique in cultivation by installing membrane sheet below the crop’s root zone was helped to save irrigation water in the root zone, less farm losses, increasing the field water use efficiency and water productivity. In this paper, the membrane sheet was installed below the root zone of zucchini during the summer growing season 2017 in open field. This research was carried out in a private field in Babil governorate at Sadat Al Hindiya Township reached 72 km from Baghdad. Surface trickle irrigation system was used for irrigation process. Two treatment plots were used, treatment plot T1

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Лесовой, Сергей, Sergey Lesovoi, Вероника Кобец, and Veronika Kobets. "Simulating Siberian Radioheliograph response to the quiet Sun." Solar-Terrestrial Physics 4, no. 4 (December 21, 2018): 82–87. http://dx.doi.org/10.12737/stp-44201811.

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The Siberian Radioheliograph (SRH) correlation plot is the time dependence of the sum of absolute values of complex correlations over all baselines. These plots are built for each operating frequency of SRH. The correlation is related not only to the spatial coherence of the incident microwave emission but also to antenna gains. That is why we have to consider real SRH antenna gains and shadowings. Correlation plots obtained by SRH are related to microwave flux density of the Sun and spatial features of microwave sources. Also the correlation plots show variability of SRH beam pattern in time

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Лесовой, Сергей, Sergey Lesovoi, Вероника Кобец, and Veronika Kobets. "Simulating Siberian Radioheliograph response to the quiet Sun." Solnechno-Zemnaya Fizika 4, no. 4 (December 20, 2018): 106–13. http://dx.doi.org/10.12737/szf-44201811.

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The Siberian Radioheliograph (SRH) correlation plot is the time dependence of the sum of absolute values of complex correlations over all baselines. These plots are built for each operating frequency of SRH. The correlation is related not only to the spatial coherence of the incident microwave emission but also to antenna gains. That is why we have to consider real SRH antenna gains and shadowings. Correlation plots obtained by SRH are related to microwave flux density of the Sun and spatial features of microwave sources. Also the correlation plots show variability of SRH beam pattern in time

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Köhler, P., J. Schmitt та H. Fischer. "On the application and interpretation of Keeling plots in paleo climate research – deciphering δ<sup>13</sup>C of atmospheric CO<sub>2</sub> measured in ice cores". Biogeosciences Discussions 3, № 3 (14 червня 2006): 513–73. http://dx.doi.org/10.5194/bgd-3-513-2006.

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Abstract. The Keeling plot analysis is an interpretation method widely used in terrestrial carbon cycle research to quantify exchange processes of carbon between terrestrial reservoirs and the atmosphere. Here, we analyse measured data sets and artificial time series of the partial pressure of atmospheric carbon dioxide (pCO2) and of δ13C of CO2 over industrial and glacial/interglacial time scales and investigate to what extent the Keeling plot methodology can be applied to longer time scales. The artificial time series are simulation results of the global carbon cycle box model BICYCLE. Our a

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Wang, Jia-Jung, Shing-Hong Liu, Wei-Kung Tseng, and Wenxi Chen. "Noninvasive Measurement of Time-Varying Arterial Wall Elastance Using a Single-Frequency Vibration Approach." Sensors 20, no. 22 (November 12, 2020): 6463. http://dx.doi.org/10.3390/s20226463.

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The arterial wall elastance is an important indicator of arterial stiffness and a kind of manifestation associated with vessel-related disease. The time-varying arterial wall elastances can be measured using a multiple-frequency vibration approach according to the Voigt and Maxwell model. However, such a method needs extensive calculation time and its operating steps are very complex. Thus, the aim of this study is to propose a simple and easy method for assessing the time-varying arterial wall elastances with the single-frequency vibration approach. This method was developed according to the

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Xin, Rui Hao, Chun Yang Wang, Xue Lian Liu, Ming Qiu Li, and Duan Yuan Bai. "Robust Fractional Order Proportional Integral Control for Large Time-Delay System." Applied Mechanics and Materials 716-717 (December 2014): 1614–19. http://dx.doi.org/10.4028/www.scientific.net/amm.716-717.1614.

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In this paper, a new control method for large time delay system is proposed. Firstly, the decreasing time delay controller is used to remodel large delay time plant into small delay time plant. Then, a fractional robust proportional-integral controller (FOPI) is designed, using the phase margin and cut-off frequency at a specified point in the Bode plot of flat robust conditions, to guarantee the desired control performance and the robustness of the high order system to the gain order system. For comparison between the fractional order proportional integral controller and the traditional integ

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Yan, Chang, Changchun Liu, Lianke Yao, Xinpei Wang, Jikuo Wang, and Peng Li. "Short-Term Effect of Percutaneous Coronary Intervention on Heart Rate Variability in Patients with Coronary Artery Disease." Entropy 23, no. 5 (April 28, 2021): 540. http://dx.doi.org/10.3390/e23050540.

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Myocardial ischemia in patients with coronary artery disease (CAD) leads to imbalanced autonomic control that increases the risk of morbidity and mortality. To systematically examine how autonomic function responds to percutaneous coronary intervention (PCI) treatment, we analyzed data of 27 CAD patients who had admitted for PCI in this pilot study. For each patient, five-minute resting electrocardiogram (ECG) signals were collected before and after the PCI procedure. The time intervals between ECG collection and PCI were both within 24 h. To assess autonomic function, normal sinus RR interval

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Qiao, Z.-G., L. Mørkrid, and N. K. Vøllestad. "Characteristics of phase angle, extrapolated conductance and ion relaxation time in the low-frequency admittance locus plot of human palmar skin." Medical & Biological Engineering & Computing 32, no. 2 (March 1994): 161–67. http://dx.doi.org/10.1007/bf02518913.

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Gilbert, Abigail L., Jungwha Lee, Madeleine Ma, Pamela A. Semanik, Loretta DiPietro, Dorothy D. Dunlop, and Rowland W. Chang. "Comparison of Subjective and Objective Measures of Sedentary Behavior Using the Yale Physical Activity Survey and Accelerometry in Patients With Rheumatoid Arthritis." Journal of Physical Activity and Health 13, no. 4 (April 2016): 371–76. http://dx.doi.org/10.1123/jpah.2015-0176.

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Background:Sedentary behavior is associated with increased risk of functional decline and disability. Individuals with rheumatoid arthritis (RA) spend more time sedentary than healthy adults. Self-reported assessment of sedentary behavior has not been well-developed in this patient population.Methods:172 adults with RA wore an accelerometer for 7 days and completed a modified version of the Yale Physical Activity Survey (YPAS). YPAS-derived sedentary estimates included 1) daily sitting categories (<3, 3 to 6, 6 to 8, >8 hours/day), 2) continuous daily sedentary time calculated by subtrac

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Chakraborty, Sudhangshu. "Investigation on relaxation phenomenon on sodium silicate (Na2SiO3) using complex impedance spectroscopy." Journal of Micromechanics and Molecular Physics 02, no. 03 (September 2017): 1750012. http://dx.doi.org/10.1142/s2424913017500126.

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The relaxation property of sodium silicate [Formula: see text] (SS) was investigated by complex impedance spectroscopy (CIS) in a wide range of frequency (100[Formula: see text]kHz–5[Formula: see text]MHz) and temperature [Formula: see text]. Orthorhombic crystal phase was synthesized by a sintering process. The CIS study shows high complex impedance in low-frequency region due to strong dispersion and controls the relaxation mechanism of ions or cations in the crystal lattice. A decrease of the energy loss [Formula: see text] occurs with increasing frequency for all temperatures showing the n

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Tang, Qiansheng, Chaofeng Li, and Bangchun Wen. "Analysis on Forced Vibration of Thin-Wall Cylindrical Shell with Nonlinear Boundary Condition." Shock and Vibration 2016 (2016): 1–22. http://dx.doi.org/10.1155/2016/8978932.

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Forced vibration of thin-wall cylindrical shell under nonlinear boundary condition was discussed in this paper. The nonlinear boundary was modeled as supported clearance in one end of shell and the restraint was assumed as linearly elastic in the radial direction. Based on Sanders’ shell theory, Lagrange equation was utilized to derive the nonlinear governing equations of cylindrical shell. The displacements in three directions were represented by beam functions and trigonometric functions. In the study of nonlinear dynamic responses of thin-wall cylindrical shell with supported clearance unde

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Cheng, Q., L. Li, and L. Wang. "Characterization of peak flow events with local singularity method." Nonlinear Processes in Geophysics 16, no. 4 (July 22, 2009): 503–13. http://dx.doi.org/10.5194/npg-16-503-2009.

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Abstract. Three methods, return period, power-law frequency plot (concentration-area) and local singularity index, are introduced in the paper for characterizing peak flow events from river flow data for the past 100 years from 1900 to 2000 recorded at 25 selected gauging stations on rivers in the Oak Ridges Moraine (ORM) area, Canada. First a traditional method, return period, was applied to the maximum annual river flow data. Whereas the Pearson III distribution generally fits the values, a power-law frequency plot (C-A) on the basis of self-similarity principle provides an effective mean fo

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Wang, Xiang, and Yuan Zheng. "Application of Harmonic Wavelet Analysis to Rubbing Vibration Signals for Rotating Machinery Fault Diagnosis." Applied Mechanics and Materials 321-324 (June 2013): 1245–48. http://dx.doi.org/10.4028/www.scientific.net/amm.321-324.1245.

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Harmonic wavelet transform (HWT)and harmonic wavelet time-frequency profile plot (TFPP) is introduced firstly in practice to identify weak singularity in a signal with noise clearly. With TFPP method, emulational signal and vibration data of the rubbing of the large practical turbo-generator units are analyzed successfully, which prove that the method is effectively extract the rubbing signal feature which is can not gained by the other signal analysis methods, and the rubbing of the turbo-generator units is identified effectively.

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Vieira, Frederico Márcio C., Matheus Deniz, Edgar S. Vismara, Piotr Herbut, Jaqueline A. Pilatti, Maurício Zotti Sponchiado, and Barbara de Oliveira Puretz. "Thermoregulatory and Behaviour Responses of Dairy Heifers Raised on a Silvopastoral System in a Subtropical Climate." Annals of Animal Science 20, no. 2 (April 1, 2020): 613–27. http://dx.doi.org/10.2478/aoas-2019-0074.

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AbstractIn this study, we investigated the influence of a silvopastoral system on the thermal environment, behaviour and thermoregulation of dairy heifers in a subtropical climate. The experiment was conducted on a dairy farm in Southwest Paraná, Brazil, during the summer of 2014. Crossbred Holstein × Jersey dairy heifers (n = 10) were used in a split-plot design. The fixed effects in this study include time of day (9:00–10:00, 13:00–14:00, and 17:00–18:00 h) under silvopastoral or open pastures conditions, which were the main-plot and split-plot factors, respectively. To assess the environmen

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Tsitoglou, Kyriakos I., Yiannis Koutedakis, and Petros C. Dinas. "Validation of the Polar RS800CX for assessing heart rate variability during rest, moderate cycling and post-exercise recovery." F1000Research 7 (September 20, 2018): 1501. http://dx.doi.org/10.12688/f1000research.16130.1.

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Background: Heart rate variability (HRV) is an autonomic nervous system marker that provides reliable information for both disease prevention and diagnosis; it is also used in sport settings. We examined the validity of the Polar RS800CX heart rate monitor during rest, moderate cycling, and recovery in considering the total of 24 HRV indices. Method: A total of 32 healthy males (age=24.78±6.87 years, body mass index=24.48±3.13 kg/m2) completed a session comprised by three 20-minute time periods of resting, cycling at 60% of maximal heart rate, and recovery using a Polar RS800CX and an electroc

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Lian, Enyang, Yingyu Ren, Yunfeng Han, Weixin Liu, Ningde Jin, and Junying Zhao. "Multi-Scale Morphological Analysis of Conductance Signals in Vertical Upward Gas–Liquid Two-Phase Flow." Zeitschrift für Naturforschung A 71, no. 11 (November 1, 2016): 1031–52. http://dx.doi.org/10.1515/zna-2016-0235.

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AbstractThe multi-scale analysis is an important method for detecting nonlinear systems. In this study, we carry out experiments and measure the fluctuation signals from a rotating electric field conductance sensor with eight electrodes. We first use a recurrence plot to recognise flow patterns in vertical upward gas–liquid two-phase pipe flow from measured signals. Then we apply a multi-scale morphological analysis based on the first-order difference scatter plot to investigate the signals captured from the vertical upward gas–liquid two-phase flow loop test. We find that the invariant scalin

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Bello, N., and K. O. Ogbeide. "Designing a Real-time Swept Spectrum Analyser with USRP B210." Nigerian Journal of Environmental Sciences and Technology 5, no. 2 (October 2021): 329–39. http://dx.doi.org/10.36263/nijest.2021.02.0275.

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Cognitive radio has received considerable amount of attention as a promising technique to provide dynamic spectrum allocation. Spectrum sensing is one of the basic functions in the cognitive radio and is crucial to all other functions. Software- defined radios (SDRs) are considered due to its very high flexibility and have become a common platform for CR implementation replacing expensive spectrum analysers. The most popular among various SDR platforms is the universal software-defined radio peripheral (USRP). This paper presents a real-time swept spectrum sensing solution based on USRP B210.

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Zeng, Ming, Zhan Xie Wu, Qing Hao Meng, Jing Hai Li, and Shu Gen Ma. "Recurrence Characteristics Analysis of Near-Surface Wind Speed Signal with Different Sampling Frequencies." Applied Mechanics and Materials 599-601 (August 2014): 1605–9. http://dx.doi.org/10.4028/www.scientific.net/amm.599-601.1605.

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The wind is the main factor to influence the propagation of gas in the atmosphere. Therefore, the wind signal obtained by anemometer will provide us valuable clues for searching gas leakage sources. In this paper, the Recurrence Plot (RP) and Recurrence Quantification Analysis (RQA) are applied to analyze the influence of recurrence characteristics of the wind speed time series under the condition of the same place, the same time period and with the sampling frequency of 1hz, 2hz, 4.2hz, 5hz, 8.3hz, 12.5hz and 16.7hz respectively. Research results show that when the sampling frequency is highe

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Kotowski, Adam. "Cross-Correlation-Based Method vs. Classical Fft for Spectral Analysis of Impulse Response." Acta Mechanica et Automatica 8, no. 4 (December 1, 2014): 219–22. http://dx.doi.org/10.2478/ama-2014-0040.

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Abstract The paper presents comparison of results of impulse response spectral analysis that has been obtained using a method based on cross-correlation with results obtained using classical FFT. The presented non-Fourier method is achieved by correlating the analyzed signal and reference single-harmonic signals and using Hilbert transform to obtain an envelope of cross-correlation. The envelope of crosscorrelation makes it possible to calculate appropriate indicator and make its plot in frequency domain as a spectrum. The spectrum obtained this way has its advantage over the FFT that the spec

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Murayama, Norimitsu, Noriya Izu, Woosuck Shin, and Ichiro Matsubara. "Application of Nano-Sized CeO₂ Powder for Fast Response Oxygen Sensors." Key Engineering Materials 421-422 (December 2009): 323–27. http://dx.doi.org/10.4028/www.scientific.net/kem.421-422.323.

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For resistive oxygen sensor elements of Ce1-xZrxO2 (x = 0.0, 0.05, 0.1, 0.2), grain diameter was varied in the range of 86 – 300 nm by changing sintering temperature or changing Zr content. The grain diameter decreased with increasing Zr content. The response time was approximately proportional to the square of the grain diameter. In the relationship between the amplitude of sensor output, An and the frequency, f of sine wave of variation in oxygen partial pressure, the gradient in the high-frequency region of a plot of log An vs. log f in was approximately –0.5. From these results, it was con

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PREMALATHA, L., and P. VANAJARANJAN. "USE OF RECURRENCE PLOT ANALYSIS FOR DETECTING CHAOS AND NOISE IN NONLINEAR SWITCHING CIRCUITS." Journal of Circuits, Systems and Computers 15, no. 03 (June 2006): 409–36. http://dx.doi.org/10.1142/s0218126606003209.

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DC–DC converters controlled by naturally sampled, constant frequency pulse width modulation give rise to a wide range of bifurcation and chaos depending on the change in the system parameter values. Knowledge of transitions from regular to chaotic behavior is essential to understand the underlying dynamics of nonlinear switching circuits. While linear approaches are often insufficient to describe such processes, there are nonlinear methods available but requires long time observations. To overcome these difficulties, a newly developed pattern recognition method of nonlinear dynamics called Rec

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Lodge, G. M. "Effects of cutting and grazing on newly sown plants of Phalaris aquatica cv. Sirosa at Tamworth, New South Wales." Australian Journal of Experimental Agriculture 47, no. 11 (2007): 1351. http://dx.doi.org/10.1071/ea06268.

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A field study was conducted (1994–97) to investigate defoliation time and frequency effects on a newly sown stand of phalaris (Phalaris aquatica cv. Sirosa). Defoliation treatments were applied from spring 1994 to autumn 1995 and effects on plant frequency and basal cover monitored until June 1997. The experimental design was a randomised split-plot in three replicates, with 45 main plots and 90 subplots. Main plots included three types of defoliation (two cutting heights or grazing with Merino sheep) applied at four different times (early stem elongation, anthesis, end of summer and end of au

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Kamiyanagi, Ayuko, Yuka Sumita, Manabu Chikai, Kenta Kimura, Yoshikazu Seki, Shuichi Ino, and Hisashi Taniguchi. "Evaluation of Swallowing Sound Using a Throat Microphone with an AE Sensor in Patients Wearing Palatal Augmentation Prosthesis." Journal of Advanced Computational Intelligence and Intelligent Informatics 21, no. 3 (May 19, 2017): 573–80. http://dx.doi.org/10.20965/jaciii.2017.p0573.

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An increase in the population of dysphagia patients due to an aging population has led to increased attention on examination methods based on swallowing sound as simple methods of screening aspiration. However, an issue with the conventional method of cervical auscultation is that its accuracy varies based on the examiner. Previous studies examined the use of throat microphones and acceleration sensors to examine the acoustic characteristics of swallowing sound. Nevertheless, extant studies to date did not reach a level of clinical application. This study focused on using a throat microphone t

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