• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.37-38
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• 2022

This study is attempted to propose an appropriate number of measurements by checking and statistically analyzing the change in hardness according to the number of measurements. As a result, there was no significant difference between the 20th and 30th data, and in the 10th case, the effect on errors occurring during measurement was found to be dominant. Therefore, as the number of measurements, proposing 20 times in consideration of the convenience of use. In addition, in order to minimize the effect on the measurement error, it is proposed to remeasure the surface mane of the measurement surface and the test value in which the error occurs on the average of the test values.

• 한국연소학회:학술대회논문집
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• 2004.11a
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• pp.91-96
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• 2004

Simultaneous CH and OH planar laser induced fluorescence(PLIF) and stereoscopic particle image velocimetry (PIV) measurements have been developed to investigate the local flame structure of turbulent premixed flames. The developed simultaneous two radical concentrations and three component velocity measurements on a two-dimensional plane was applied for relatively high Reynolds number turbulent premixed flames in a swirl stabilized combustor. All measurements were conducted for methane-air premixed flames in the corrugated flamelets regime. Strong three-dimensional fluctuation implies that misunderstanding of the flame/turbulent interactions would be caused by the analysis of two-component velocity distribution in a cross section. Furthermore, comparisons of CH-OH PLIF and three-component velocity field show that the burned gases not always have high-speed velocity in relatively high Reynolds number turbulent premixed flame. The Reynolds number dependence of the flame front was clearly captured by the simultaneous CH-OH PLIF and stereoscopic PIV measurements.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.1
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• pp.58-78
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• 2016

Compressed sensing (CS) possesses the potential benefits for spectrum sensing of wideband signal in cognitive radio. The sparsity of signal in frequency domain denotes the number of occupied channels for spectrum sensing. This paper presents a scheme of adaptively adjusting the number of compressed measurements to reduce the unnecessary computational complexity when priori information about the sparsity of signal cannot be acquired. Firstly, a method of sparsity estimation is introduced because the sparsity of signal is not available in some cognitive radio environments, and the relationship between the amount of used data and estimation accuracy is discussed. Then the SNR of the compressed signal is derived in the closed form. Based on the SNR of the compressed signal and estimated sparsity, an adaptive algorithm of adjusting the number of compressed measurements is proposed. Finally, some simulations are performed, and the results illustrate that the simulations agree with theoretical analysis, which prove the effectiveness of the proposed adaptive adjusting of compressed measurements.

• Journal of Positioning, Navigation, and Timing
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• v.2 no.1
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• pp.59-65
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• 2013

The signal broadcast from a GPS satellite experiences code delay and carrier phase advance while passing through the ionosphere, which causes a signal error. Many ionosphere models have been studied to correct this ionospheric delay error. In this paper, the ionosphere modeling for the Korean Peninsula was carried out using a spherical harmonics based model. In contrast to the previous studies, we considered a real-time ionospheric delay correction model using fewer number of basis functions. The modeling performance was evaluated by comparing with a grid model. Total number of basis functions was set to be identical to the number of grid points in the grid model. The performance test was conducted using the GPS measurements collected from 5 reference stations during 24 hours. In the test result, the modeling residual error was smaller than that of the existing grid model. However, when the number of measurements was small and the measurements were not evenly distributed, the overall trend was found to be problematic. For improving this problem, we implemented the modeling with additional virtual measurements.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.3
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• pp.209-218
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• 2013

Military surveillance systems with electro-optical sensors can be used to track a number of targets efficiently and reliably. In MTT (Multi-Target Tracking), joint events in which different tracks share the same measurements may occur. Measurement-to-track assignment are computationally challenging because of the number of operations increases exponentially with number of tracks and number of measurements. IHPDA (Integrated Highest Probability Data Association) based on a 2D-Assignment technique can find an optimal solution for measurement to track one-to-one assignments for complex environments. In this paper, LM-IHPDA (Linear Multi-Target IHPDA) which does not need to form all feasible joint events of association and thus the computational load is linear in the number of tracks and the number of measurements. Simulation studies illustrate the effectiveness of this approach in an infrared image environment.

• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.299-310
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• 2003

In the evaluation of the subgrade stiffness structure by the SASW method, the calculation of the phase velocities is the important task controlling the reliability of the result. The interpretation of the phase spectrum should precede the phase-velocity calculation in the current practice of the SASW method. The difficulty involved in the interpretation prohibited the SASW method from being spread over to the industry. This study proposed a new method called the frequency-wave number technique, which is based on the frequency-wave number relationship of the surface wave in the multi-layered system. The frequency-wave number technique eliminates the expertise in the interpretation of the phase spectrum, automates the phase-velocity calculation and expedites the determination of the phase-velocity dispersion curve. To verify the validity of the proposed frequency-wave number method, the transfer function determined from the numerical simulation of the SASW measurements was used fir the calculation of the automatic calculation of the phase velocities and compared with the phase velocities by WinSASW employing the phase-unwrapping method. Also, the proposed method was applied to the real SASW measurements performed at$\bigcirc$$\bigcirc$area in GyeongGi-Do to see how the proposed method works with the real measurements.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.947-950
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• 2008

This paper reports of traceable and repeatable time resolved colorimetric measurements of the luminance- and colour variation occurring during the frame refresh period of FPD's. During one frame period a number of measurements are performed, and for the dynamic artifacts a simulated smooth pursuit eye tracking algorithm is included.

• Nuclear Engineering and Technology
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• v.52 no.8
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• pp.1807-1816
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• 2020

In this work, a Gaussian Process (Kriging) approach is proposed to provide efficient dose mapping for complex radiation fields using limited number of responses. Given a few response measurements (or simulation data points), the proposed approach can help the analyst in completing a map of the radiation dose field with a 95% confidence interval, efficiently. Two case studies are used to validate the proposed approach. The First case study is based on experimental dose measurements to build the dose map in a radiation field induced by a D-D neutron generator. The second, is a simulation case study where the proposed approach is used to mimic Monte Carlo dose predictions in the radiation field using a limited number of MCNP simulations. Given the low computational cost of constructing Gaussian Process (GP) models, results indicate that the GP model can reasonably map the dose in the radiation field given a limited number of data measurements. Both case studies are performed on the nuclear engineering radiation laboratories at the University of Sharjah.

• Journal for History of Mathematics
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• v.18 no.3
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• pp.55-66
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• 2005

In our school mathmatics, the irrational numbers and the real numbers are defined and instructed on the basis of decimal fractions. In relation to this fact, we identified the essences of the real number and the irrational number defined by the decimal fractions through the historical analysis. It is revealed that the formation of real numbers means the numerical measurements of all magnitudes and the formation of irrational numbers means the numerical measurements of incommensurable magnitudes. Finally, we suggest instructional plan for the meaninful understanding of the real number concept.

• Korean Journal of Oriental Medicine
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• v.18 no.3
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• pp.111-118
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• 2012

Objective : The aim of this study was to investigate the number of measurements and visits for blood pressure measurement. We also analyzed the change of blood pressure based on the measurement method and measurement interval. Methods : Data of three clinical trials evaluating the effect of acupuncture, moxibustion, and qigong for pre and mild essential hypertension were used. Blood pressure was measured 3 times each visit with 1 or 5 minutes interval, and it was checked until $3^{rd}$ visit. Two trials used sphygmomanometer and another one trial used automatic device for blood pressure measurement. Results : The mean difference between $1^{st}$ and $2^{nd}$, and $2^{nd}$ and $3^{rd}$ measurement were significant in systolic (p<0.001) and diastolic blood pressure (p<0.001). However, in automated measurement or measuring with 1 minute interval, the difference between $2^{nd}$ and $3^{rd}$ was not significant. The mean of $1^{st}$ and $2^{nd}$ measurements was also significantly different from the mean of all three measurements in both systolic (p<0.001) and diastolic blood pressure (p<0.001). While the difference between each visit was not significant in diastolic blood pressure, the systolic blood pressure difference was significant between $1^{st}$ and $2^{nd}$ visit in automated and manual measurement. Conclusion : The mean of two measurements and three measurements were significantly different. The change of blood pressure was different according to the method and interval of blood pressure measurement.