scholarly journals Estimation of the Absolute Error of the Normalized Frequency of a Sinusoidal Signal During Its Discretization In Time

2020 ◽  
pp. 40-44
Author(s):  
V. U. Ignatkin ◽  
O. G. Saragtov
Keyword(s):  
Absolute Error ◽  
Sine Wave ◽  
Spectral Lines ◽  
Sinusoidal Signal ◽  
Integer Number ◽  
Normalized Frequency ◽  
Class 1 ◽  
The Absolute ◽  
Rate Of Decline ◽  
Sample Ratio

The influence of systematic errors due to the influence of the imaginary part in the spectrum of a sinusoidal signal on the zinc of its normalized frequency using the method of discrete Fourier transform (DFT) with interpolation with a maximum decay rate of the side lobes is analyzed. Results are given for estimating the absolute error of the normalized frequency and conditions are found for the minimum integer number of sine wave cycles, taking into account which guarantees the value of this error is less than a certain given level. The reliability of the results received is confirmed by computer simulation. In practice, the frequencies of the sinusoidal signal and the sample do not satisfy the coherent sample ratio, which results in the well-known effect of erosion or «leakage» of the spectrum components. This means that the energy of the spectral lines propagates along the frequency axis. To reduce the errors associated with blurring the spectrum, leaching is used. The best results were achieved in the case of «age» with a maximum rate of decline of the side lobes (SSBL), which include the «windows» of Rife-Vincent’s class 1 and the use of the corresponding ratios.

scholarly journals Prediction of One Repetition Maximum Using Reference Minimum Velocity Threshold Values in Young and Middle-Aged Resistance-Trained Males

2021 ◽  
Vol 11 (5) ◽  
pp. 71
Author(s):  
John F. T. Fernandes ◽  
Amelia F. Dingley ◽  
Amador Garcia-Ramos ◽  
Alejandro Perez-Castilla ◽  
James J. Tufano ◽  
...  
Keyword(s):  
Bench Press ◽  
Absolute Error ◽  
Young Group ◽  
Middle Aged ◽  
Repetition Maximum ◽  
Back Squat ◽  
Velocity Threshold ◽  
Low Load ◽  
The Absolute ◽  
Minimum Velocity

Background: This study determined the accuracy of different velocity-based methods when predicting one-repetition maximum (1RM) in young and middle-aged resistance-trained males. Methods: Two days after maximal strength testing, 20 young (age 21.0 ± 1.6 years) and 20 middle-aged (age 42.6 ± 6.7 years) resistance-trained males completed three repetitions of bench press, back squat, and bent-over-row at loads corresponding to 20–80% 1RM. Using reference minimum velocity threshold (MVT) values, the 1RM was estimated from the load-velocity relationships through multiple (20, 30, 40, 50, 60, 70, and 80% 1RM), two-point (20 and 80% 1RM), high-load (60 and 80% 1RM) and low-load (20 and 40% 1RM) methods for each group. Results: Despite most prediction methods demonstrating acceptable correlations (r = 0.55 to 0.96), the absolute errors for young and middle-aged groups were generally moderate to high for bench press (absolute errors = 8.2 to 14.2% and 8.6 to 20.4%, respectively) and bent-over-row (absolute error = 14.9 to 19.9% and 8.6 to 18.2%, respectively). For squats, the absolute errors were lower in the young group (5.7 to 13.4%) than the middle-aged group (13.2 to 17.0%) but still unacceptable. Conclusion: These findings suggest that reference MVTs cannot accurately predict the 1RM in these populations. Therefore, practitioners need to directly assess 1RM.

Investigation of Heat Transfer for Shell-Tube Fuel-Cooled Heat Exchanger

2013 ◽  
Vol 378 ◽  
pp. 459-465
Author(s):  
Ya Guo Lu ◽  
Peng Fei Zhu
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Relative Error ◽  
Absolute Error ◽  
Heat Transfer Characteristics ◽  
Shell Side ◽  
Transfer Characteristics ◽  
Aero Engine ◽  
The Absolute

A calculate method based on ε-NTU model for heat transfer characteristics of shell-tube fuel-cooled heat exchanger of aero-engine lubrication system was built. The heat convection coefficient was obtained by a dimensionless curve (Re~StPr2/3), which was detailed introduced as well. A case study was executed at last. The absolute error of the outlet lubrication of the tube side and the shell side between the value of calculation and experiment was less than ±10°C, and the relative error was less than 6.5%. The absolute error of the heat transferred between calculation and experiment was less than ±0.9kW, and the relative error was less than 7.4%. It indicates that the mothod is available for the investigation of heat transfer characteristics of shell-tube fuel-cooled heat exchanger.

scholarly journals Comparison of MODIS and AERONET derived aerosol optical depth over the Ganga Basin, India

2005 ◽  
Vol 23 (4) ◽  
pp. 1093-1101 ◽  
Author(s):  
S. N. Tripathi ◽  
Sagnik Dey ◽  
A. Chandel ◽  
S. Srivastava ◽  
Ramesh P. Singh ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Time Window ◽  
Absolute Error ◽  
Absolute Difference ◽  
Ganga Basin ◽  
Monsoon Period ◽  
Post Monsoon ◽  
Dust Loading ◽  
The Absolute

Abstract. The Moderate Resolution Imaging Spectroradiometer (MODIS) onboard EOS Terra measures global aerosol optical depth and optical properties since 2000. MODIS aerosol products are freely available and are being used for numerous studies. In this paper, we present a comparison of aerosol optical depth (AOD) retrieved from MODIS with Aerosol Robotic Network (AERONET) data for the year 2004 over Kanpur, an industrial city lying in the Ganga Basin in the northern part of India. AOD retrieved from MODIS (τaMODIS) at 0.55µm wavelength has been compared with the AERONET derived AOD (τaAERONET), within an optimum space-time window. Although the correlation between τaMODIS and τaAERONET during the post-monsoon and winter seasons (R2~0.71) is almost equal to that during the pre-monsoon and monsoon seasons (R2~0.72), MODIS is found to overestimate AOD during the pre-monsoon and monsoon period (characterized by severe dust loading) and underestimate during the post-monsoon and winter seasons. The absolute difference between τaMODIS and τaAERONET is found to be low (0.12±0.11) during the non-dust loading season and much higher (0.4±0.2) during dust-loading seasons. The absolute error in τaMODIS is found to be about ~25% of the absolute values of τaMODIS. Our comparison shows the importance of modifying the existing MODIS algorithm during the dust-loading seasons, especially in the Ganga Basin in northern part of India.

scholarly journals Intraocular Lens Power Calculation According to the Difference between Anterior and Total Keratometry Using Scheimpflug Imaging

2021 ◽  
Vol 62 (9) ◽  
pp. 1181-1188
Author(s):  
Joong Hee Kim ◽  
Kyong Jin Cho ◽  
Ho Seok Chung
Keyword(s):  
Regression Analysis ◽  
Absolute Error ◽  
Power Calculation ◽  
Intraocular Lens Power Calculation ◽  
Refractive Power ◽  
Simple Regression Analysis ◽  
The Absolute ◽  
The Difference ◽  
Lens Power ◽  
Simple Regression

Purpose: We investigated the change in the absolute error according to the difference between anterior and total keratometry, to determine the criterion for the difference in keratometry, and to determine the indication for using total keratometry. Methods: Sagittal and total refractive power were measured with 2-, 3-, and 4-mm Pentacam® rings, and the absolute error of each was calculated in patients who underwent cataract surgery in our hospital. The correlation between the difference value the sagittal minus the total refractive power and each absolute error was analyzed by simple regression analysis. The analysis was performed by dividing the patients into two groups based on 0.6, which is the average of the difference between the sagittal and total refractive power for the 3-mm ring. Results: Sagittal power was larger than total refractive power for all rings and the absolute error obtained by applying the total refractive power was larger than the sagittal power for the 2- and 4-mm rings (p < 0.001). The simple regression analysis revealed that the absolute error using sagittal power was positively correlated with the difference between sagittal power and total refractive power. In the group with less than 0.6, the absolute error using the total refractive power of all rings was larger than the sagittal power (p < 0.001). In the group exceeding 0.6, the absolute error using the total refractive power was less than using the sagittal power for the 3 mm ring (p = 0.028). Conclusions: The greater the difference between sagittal and total refractive power, the greater the absolute error using sagittal power. Accuracy was higher in the group exceeding 0.6 after applying total refractive power measured at the 3 mm ring compared to sagittal power.

scholarly journals FMCW Laser Fuze Multiple Scattering Model and Accurate Fixed-Distance Algorithm in a Smoke Environment

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2604
Author(s):  
Chengtian Song ◽  
Ying Cui ◽  
Bohu Liu
Keyword(s):  
Spectral Density ◽  
Multiple Scattering ◽  
Continuous Wave ◽  
Absolute Error ◽  
Suspended Particles ◽  
Scattering Model ◽  
Fixed Distance ◽  
The Absolute

In a smoke environment, suspended particles can scatter and absorb laser photons, making target echo signals extremely weak and difficult to extract and identify, which causes obvious difficulty in fixed-distance of laser fuze. In this paper, the multiple scattering model of frequency-modulated-continuous-wave (FMCW) laser fuze in a smoke environment was established. This model simulates multi-path propagation and multiple scattering of photons. At the same time, we use the correntropy spectral density (CSD) algorithm for accurate fixed-distance of FMCW laser fuze. The absolute error of distance does not exceed 0.15 m in smoke interference environment.

scholarly journals Comparison of Predictability Using Barrett Universal II and SRK/T Formulas according to Keratometry

2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Kei Iijima ◽  
Kazutaka Kamiya ◽  
Yoshihiko Iida ◽  
Nobuyuki Shoji
Keyword(s):  
Prediction Error ◽  
Pearson Correlation ◽  
Absolute Error ◽  
Power Calculation ◽  
Universal Formula ◽  
Iol Power Calculation ◽  
Iol Power ◽  
The Absolute ◽  
Relationship Of ◽  
The Relationship

Purpose. To compare the predictability of intraocular lens (IOL) power calculation using the Barrett Universal II and the SRK/T formulas, according to the keratometry. Methods. We retrospectively reviewed the clinical charts of 335 consecutive eyes undergoing standard cataract surgery. IOL power calculations were performed using the Barrett Universal II and the SRK/T formulas. We compared the prediction error, the absolute error, and the percentages within ±0.25, ±0.5, and ±1.0 D of the targeted refraction, 1 month postoperatively, and also investigated the relationship of these outcomes with the keratometric readings, using the two formulas. Results. The prediction error using the SRK/T formula was significantly more myopic than that using the Barrett Universal II formula (the paired t-test, p<0.001). The absolute error using the SRK/T formula was significantly larger than that using the Barrett Universal II formula (p=0.006). We found a significant correlation between the prediction error and the keratometric readings using the SRK/T formula (Pearson correlation coefficient, r = −0.522, p<0.001), but there was no significant correlation between them using the Barrett Universal II formula (r = −0.031, p=0.576). Conclusions. The Barrett Universal II formula provides a better predictability of IOL power calculation and is less susceptible to the effect of the corneal shape, than the SRK/T formula. The Barrett Universal formula, instead of the SRK/T formula, may be clinically helpful for improving the refractive accuracy, especially in eyes with steep or flat corneas.

Audio Authentication by Exploring the Absolute-Error-Map of ENF Signals

2016 ◽  
Vol 11 (5) ◽  
pp. 1003-1016 ◽  
Author(s):  
Guang Hua ◽  
Ying Zhang ◽  
Jonathan Goh ◽  
Vrizlynn L. L. Thing
Keyword(s):  
Absolute Error ◽  
Audio Authentication ◽  
The Absolute

Lattice orbit distribution on ℝ2

2009 ◽  
Vol 30 (4) ◽  
pp. 1201-1214 ◽  
Author(s):  
ARNALDO NOGUEIRA
Keyword(s):  
Ergodic Theory ◽  
Diophantine Approximation ◽  
Error Term ◽  
Absolute Error ◽  
Compact Set ◽  
Linear Action ◽  
Counting Problem ◽  
Asymptotical Behaviour ◽  
Diophantine Property ◽  
The Absolute

AbstractWe study the distribution on ℝ2 of the orbit of a vector under the linear action of SL(2,ℤ). Let Ω⊂ℝ2 be a compact set and x∈ℝ2. Let N(k,x) be the number of matrices γ∈SL(2,ℤ) such that γ(x)∈Ω and ‖γ‖≤k, k=1,2,…. If Ω is a square, we prove the existence of an absolute error term for N(k,x), as k→∞, for almost every x, which depends on the Diophantine property of the ratio of the coordinates of x. Our approach translates the question into a Diophantine approximation counting problem which provides the absolute error term. The asymptotical behaviour of N(k,x) is also obtained using ergodic theory.

Experimental Study of Methane Sensor Based on the Principle of Infrared Detection

2014 ◽  
Vol 590 ◽  
pp. 651-655
Author(s):  
Yun Cheng Li ◽  
Yong Zhi Liang ◽  
Xi Sheng Ma ◽  
Wen Pei Jia
Keyword(s):  
Structural Design ◽  
Absolute Error ◽  
Least Square ◽  
Infrared Detection ◽  
Experimental Calibration ◽  
Methane Sensor ◽  
Methane Gas ◽  
Fitting Method ◽  
The Absolute ◽  
Least Square Fitting Method

This paper presents a structural design of a methane sensor based on the principle of infrared detection, and designs a program of the experimental calibration. In the conditions of laboratory, different concentrations of methane gas were detected. A concentration inversion formula was proposed by the segmented least-square fitting method. The sensor can measure concentrations of methane in a real-time and accurate way, it contains the functions that digital display and sound and light alarm. The results show that a full-scale concentrations of methane gas can be detected, when the concentration range is in 0-10%, the absolute error is less than 0.09%; when it is more than 10%, the absolute error is less than 0.2%, the response time is less than 15s.

Determination and Evaluation of Dead Time for X-Ray Fluorescence Spectrometer

2013 ◽  
Vol 544 ◽  
pp. 445-449
Author(s):  
Ran Yan ◽  
Yu Bing Liu ◽  
Ping Dai
Keyword(s):  
Dead Time ◽  
Practical Method ◽  
Spectral Lines ◽  
Fluorescence Detector ◽  
X Ray ◽  
Analyte Content ◽  
Pair Method ◽  
Fluorescence Spectrometer ◽  
Sample Ratio

When an X-ray photon which is generated by the sample enters into the detector, pulses can be produced and recorded. The detector is unable to respond to another photon that enters at the same time when a photon is being detected. The time that the detector takes to respond to a photon is regarded as dead time. For the x-ray fluorescence detector, the recorded count is less than the real count impulse due to dead time. Hence, to correct x-ray intensity of samples whose element content is vastly different, determination of dead time is necessary. In this paper, a new and complete way to determine dead time is proposed, which can be summarized as “intensity pair method”. Three “intensity pairs” were used for determining dead time, which were “intensity pair” of collimators (S2 and S4), “intensity pair” of spectral lines (Kα and Kβ) and “intensity pair” of beads with different flux-sample ratio (higher SH and lower SL analyte content in the beads). It comes to a conclusion that dead time obtained from “intensity pair” of beads is the most practical method for correcting X-ray fluorescence intensity. As for routine analysis, the dead time of proportional counter can be accurate to 1×10-9s, which can make intensity correction error less than 0.1%.

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