• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.4 no.2
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• pp.143-152
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• 2000

As muscular contraction is sustained, the Fourier spectrum of the myoelectric signal is shifted toward the lower frequency. This spectral density is associated with muscle fatigue. This paper describes a quantitative measurement method that performs the measurement of localized muscle fatigue by tracking changes of median frequency based on stationary wavelet transform. Applying to the human masseter muscle, the proposed method offers the much information for muscle fatigue, comparing with the conventional FFT-based method for muscle fatigue measurement.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.5
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• pp.633-638
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• 2017

The small unmanned robot developed in this paper can perform tasks such as surveillance and reconnaissance in the battle field. The noise generated during the operation of the robot may expose the operation area. Therefore, in this study, we developed a method to quantitatively measure the noise of the developed small unmanned ground robot. The criteria for noise measurement in indoor and outdoor are presented. It was used for statistical verification method to verify the reliability of the developed noise measurement method. The noise was measured at different places, and the correlation was analyzed. Thus, we proposed a method to predict the noise level in the operation area where the robot is operated by the noise test data measured during the development process.

• Particle and aerosol research
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• v.12 no.1
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• pp.21-26
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• 2016

In order to realize In-line and convenient measurement for solid-gas two phase flows, Light Transmission Fluctuation (LTF) based on the random variation of transmitted light intensity, light scattering theory and cross-correlation method was presented for online measurement of particle size, concentration and velocity. The statistical relationship among transmitted light intensity, particle size and particle number in measurement zone was described by Beer-Lambert Law. Accordingly, the particle size and concentration were determined from the fluctuation signal of transmitted light intensity. Simultaneously, the particle velocity was calculated by cross-correlation analysis of two neighboring light beams. By considering the influence of concentration variation in industrial applications, the improved algorithm based on spectral analysis of transmitted light intensity was proposed to improve measurement accuracy and stability. Therefore, the online measurement system based on LTF was developed and applied to measure pulverized coal in power station and raw material in cement plant. The particle size, concentration and velocity of powder were monitored in real-time. It can provide important references for optimal control, energy saving and emission reduction of energy-intensive industries.

• Proceedings of the KWS Conference
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• 1993.05a
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• pp.132-134
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• 1993

The conventional way of molten nugget size measurement in welding process have utilized the metal-microscope by examining the micro sectioned weld specimen after micro-etching procedure. This paper proposes a new method for exact measurement of molten nugget size with the aid of the digital image processing unit and some developed software. This method proved to be convenient and precise in that resulting resolution and accuracy are as good as that of the conventional method.

• Proceedings of the KIEE Conference
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• 2000.11a
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• pp.79-81
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• 2000

Measurement used electrical sounding(MacOHM 2115, Japan) for large scale grounding resistance of So-Yang Dam hydroelectric power plant. To applied measurement method is fall of potential method. This result propose to method of efficient administration for grounding system.

• International Journal of Highway Engineering
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• v.15 no.6
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• pp.25-32
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• 2013

PURPOSES : The purpose of this study is to provide the method of how to measure the coefficient of thermal expansion of concrete using temperature compensation principle of electrical resistance strain gauge. METHODS : The gauge factor compensation method and thermal output(temperature-induced apparent strain) correction method of self-temperature compensation gauge were investigated. From the literature review, coefficient of thermal expansion measurement method based on the thermal output differential comparison between reference material(invar) and unknown material(concrete) was suggested. RESULTS : Thermal output is caused by two reasons; first the electrical resistivity of the grid conductor is changed by temperature variation and the second contribution is due to the differential thermal expansion between gauge and the test material. Invar was selected as a reference material and it's coefficient of thermal expansion was measured as $2.12{\times}10^{-6}m/m/^{\circ}C$. by KS M ISO 11359-2. The reliability of the suggested measurement method was evaluated by the thermal output measurement of invar and mild steel. Finally coefficient of thermal expansion of concrete material for pavement was successfully measured as $15.45{\times}10^{-6}m/m/^{\circ}C$. CONCLUSIONS : The coefficient of thermal expansion measurement method using thermal output differential between invar and unknown concrete material was evaluated by theoretical and experimental aspects. Based on the test results, the proposed method is considered to be reasonable to apply for coefficient of thermal expansion measurement.

• Proceedings of the Optical Society of Korea Conference
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• 1990.02a
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• pp.82-86
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• 1990

A camera type optical bench system equipped with a lens collimator and an image analyzer is fabricated to measure the equivalent focal length and distortion of lenses. This system is automatized by the computer which controls stepping motors. A nodal slide optical bench system equipped with an off axis reflective collimator is fabricated and improved by using rotating arms and air bearing system. distortion measurement on a wide angle lens using the camera method and the nodal slide method is reported. Defocusing error in the distortion measurement with the nodal slide optical bench is analyzed and improved by iteration method to search the correct image point.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.686-689
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• 2004

As the demands of X-Y linear motors increase, it becomes very important to measure flatness errors and to compensate them. In this study, in order to investigate flatness errors, a laser interferometer is used for measurement. To improve the measurement efficiency, a Union Jack method is adopted instead of a square method. The square method is frequently used because of its accuracy, but it requires many measurement points. In this study, the Union Jack method with Grey Theory is used. By using the Grey Theory, unmeasured data are predicted, and these are compared with results of the square method. The results show that the Union Jack method with Grey Theory is accurate enough to replace the square method.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.403-408
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• 2003

This paper presents measurement to develop load model for electric locomotive. Load model is defined as polynomial form and each coefficient is solved by the least square method. Therefore, many data is required for using this method. The measurement is performed on KNR line, from Chongryangri to Donghae. The subject of measurement is voltage, current, active power, reactive power an frequency for EL8100.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.1030-1041
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• 2018

The aim of this paper is to design a centrifugal deformation error compensation method with guaranteed performance that allows angular velocity measurement of the magnetically suspended sensitive gyroscopes (MSSGs). The angular velocity measurement principle and the structure of the MSSG are described, and the analytical model of errors caused by MSSG rotor centrifugal deformation is established. Then, an on-line rotor centrifugal deformation error compensation method based on measurement of rotor spinning speed in real-time has been designed. The common issues caused by centrifugal deformation of spinning rotors can be effectively resolved by the proposed method. Comparative experimental results before and after compensation demonstrate the validity and superiority of the error compensation method.