• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.700-703
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• 2003

The test method of ASTM E 756 and KS D 0076 to estimate vibration-damping properties is compared. Comparison method depending on specimen support, exciting method and calculation method for loss factor is used. Half-power bandwidth method and vibration decay method is used in the calculation method for loss factor, and Young's modulus is decided by geometric character and density for specimen and resonance frequency. Vibration measurement sensor is compared by using non-contact displacement detector, velocity detector and accelerometer. This paper is also presented the matter which is able to cause error in the measurement

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.736-738
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• 2014

The paper deals with the accuracy comparison between two kinds of ultrasonic paths for flow rate measurement. In the Z-path, two transducers are installed on the opposite side of each other on a pipe, and the ultrasonic waves generated of one transducer propagate and arrive at the other one only through refraction. In the V-path, two transducers are installed on one side of a pipe, and the ultrasonic waves reflected at the inner wall of the pipe are received. The backgrounds were established to select one path to fit the usage by considering the advantages and disadvantages.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1604-1612
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• 2009

This study introduces comparison the testing results of the AL car body which is applied to FSW and GMAW welding method. The car body is made of aluminum structure materials like a sandwich panel. The static load test was performed to evaluate the structural characteristic and stability of the AL car body. Considering the vertical, compressive, twisting load and 3-point supporting, Bend natural frequency Measurement, Twist natural frequency Measurement type as a testing terms, the structural stability of a car body was evaluated.

• 전기학회논문지P
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• 제59권3호
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• pp.305-310
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• 2010

DC electricity feeder system operating in the urban railway is typically a feedback circuit consisted of the contact wire and electric railway vehicle via rail. But stray current is flowed on a structure that is not part of the intended electrical circuit with respect to a given structure. This paper presents comparison analysis of field test cases based on criteria of electrolytic corrosion protection of buried metallic structures adjacent to DC traction systems. As a result of it, we confirmed that measurement methods are different from each other about the same tests. Therefore measurement methods to prevent electrolytic corrosion need to establish electrical facilities standards to be applied domestic.

• 한국의류학회지
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• 제15권2호
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• pp.151-162
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• 1991

The purpose of this study was to examine the point at issue unfitness and unclassification in figures for clothing construction. Comparing measurements of 3 sold figures and physical body by Suck·Go method and 19 items were selected. These items were acquired by factor analysis and cluster analysis an measurements of 200 women in twenties. The results were as follows; 1. Comparison between measurement of figures and physical body; There was not so much difference among figures, but significant difference between figures and physical body. 2. Comparison between measurement of surface area of figures and physical body; There was similar to each figure, but significant difference between figures and physical body. Mostly, figures were bigger than physical body in front parts but smaller in back parts. 3. There were 8 items selected by factor analysis; That is bust girth, waist girth, hip girth, neck base girth, posterior waist length, bust point length, chest breadth and armscye girth. 4. There were 7 clusters selected by cluster analysis.

• International Journal of Automotive Technology
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• 제6권2호
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• pp.119-124
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• 2005

Size distribution of diesel particles measured by ELPI and SMPS were compared. The results of ELPI and SMPS showed acceptable agreements in the qualitative comparison but showed differences in the quantitative comparison. In addition, the results of ELPI and SMPS showed a same trend about the change of engine loads. In this study, the effects of dilution methods and measuring positions on the measurement of PM size distribution were also studied by using the SMPS. As results, the decrease of large particles and the increase of small particles were observed when the dilution air was heated. It was also observed that the number concentration of the diesel particles was varied within 20$\%$ by the different measuring positions of 140 cm.

• Journal of the Korean Physical Society
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• 제73권10호
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• pp.1466-1472
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• 2018

A key comparison has been made between the air-kerma standards of the National Institute of Metrology (NIM), China, and other Asia Pacific Metrology Programme (APMP) members in the medium-energy X-ray. This paper reviews the primary standard Free-air ionization chamber correction factor experimental method and Monte Carlo simulation method in the NIM. The experimental method and the Monte Carlo simulation method are adopted to obtain the correction factor for the medium-energy X-ray primary standard free-air ionization chamber at 100 kV, 135 kV, 180 kV, 250 kV four CCRI reference qualities. The correction factor has already been submitted to the APMP as key comparison data and the results are in good agreement with those obtained in previous studies. This study shows that the experimental method and the EGSnrc simulation method are usually used in the measurement of the correction factor. In particular, the application of the simulation methods is more common.

• 제어로봇시스템학회논문지
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• 제9권7호
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• pp.507-514
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• 2003

Inspection and shape measurement of three-dimensional objects are widely needed in industries for quality monitoring and control. Recently the shape measurement using interferometric principle is found to be a successful methodology among other visual or optical technologies. Especially, the measuring method using wavelength scanning interferometer(WSI) has a great advantage in comparison with other conventional jnterferometric methods in that the absolute distance from the reference surface can be directly obtained from the amount of jnterferometric phase change. However, the measurement methods using WSI proposed by other researchers have low measurement resolution so far because they can't measure fractional phase change. To avoid this shortcoming we propose a new algorithm in this paper, which can obtain a small amount of even fractional phase change by sinusoidal function fitting. To evaluate the effectiveness of the proposed sinusoidal function fitting algorithm, a series of measuring experiments are conducted for discontinuously shaped specimens which have various height. The proposed algorithm shows much more enhanced measurement resolution than other existing conventional algorithms such as zero crossing algorithm and Fourier transform algorithm.

• Journal of Mechanical Science and Technology
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• 제19권7호
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• pp.1449-1459
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• 2005

This paper shows the results of local flow speed measurement using tunable AC thermal anemometry, which is suitable for the accurate measurement of wide range flow speed. The measurement accuracy is verified through the comparison between the measurement data and the analytic solution of the sensor temperature oscillation in stationary fluid. The relation between the phase lag and the flow speed is experimentally investigated at various conditions. The measurement sensitivity for low flow speed improves in a low frequency region and that for high flow speed improves in a high frequency region. Also, the sensitivity increases with decreasing thermal conductivity of the surrounding fluid. The local flow speed could be measured as low as 1.5 mm/s and the highest measurement resolution was 0.05 mm/s in the range of 4.5 $\~$5.0 mm/s at 1 Hz in this experiment.

• 한국항공운항학회지
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• 제26권2호
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• pp.91-97
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• 2018

High-energy charged particles are comprised of galactic cosmic rays and solar energetic particles which are mainly originated from the supernova explosion, active galactic nuclei, and the Sun. These primary charged particles which have sufficient energy to penetrate the Earth's magnetic field collide with the Earth's upper atmosphere, that is $N_2$ and $O_2$, and create secondary particles and ionizing radiation. The ionizing radiation can be measured at commercial flight altitude. So it is recommended to manage radiation dose of aircrew as workers under radiation environment to protect their health and safety. However, it is hard to deploy radiation measurement instrument to commercial aircrafts and monitor radiation dose continuously. So the numerical model calculation is performed to assess radiation exposure at flight altitude. In this paper, we present comparison result between measurement data recorded on several flights and estimation data calculated using model and examine the characteristics of the radiation environment in the atmosphere.