• 대한기계학회논문집B
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• 제32권9호
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• pp.712-719
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• 2008

Light Oil Flow Standard System(LOFSS), as a national oil flow standard system, in Korea Research Institute of Standards and Science(KRISS) was developed for oil flowmeter calibration, and the expanded uncertainty of flow quantity determination was estimated within 0.04 %. In order to improve the reliability of the LOFSS measurement, a proficiency test was carried out in the flow range of 20 and $240\;m^3/h$ (Reynolds number $20,000{\sim}900,000$). A turbine flowmeter was used as a transfer package in round robin test. The water flow standard system of KRISS, the pipe prover of the national calibration and test organization and the master meter calibrator of the turbine flowmeter supplier, which used the different working fluid respectively, were compared with the turbine flowmeter measurement. The maximum difference of measurement was 0.15 % between the LOFSS and the pipe prover. The En numbers of the each system measurement were evaluated at the same Reynolds number. It was found that the En numbers were less than 1 in the comparison, which means the procedures of the uncertainty estimation of the each calibrators were reasonable and reliable.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.219-223
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• 2004

Korea Railroad Research Institute(KRRI) propelled sensing and measurement techniques development for measure of Lateral Force and Vertical Force With Italy to international cooperation research project for laser technology for measurement of wheel/rail interaction force. In this paper, we compared the laser technology for measurement of wheel/rail interaction force with the existing method. And then, we suggests interaction force measurement system procedure of hereafter.

• 한국의류학회지
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• 제33권8호
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• pp.1190-1202
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• 2009

A 3D body scan measurement (SM) is used as an alternative to physical measurements (PM) as the information for designing industrial products. This study compared the mean difference (MD) between SM and PM by gender and analyzed the causes of the difference. The data used in this study were the scan measurements and physical measurements of adults aged twenty to seventy years old of the fifth Size Korea survey. The results of this study are as follows: 1. The comparison of MD between men and women for all subjects: The measurement of the significant differences between men and women were height, neck base girth, chest girth, under-bust girth, waist girth, armscye girth, back length, and foot length. The causes of difference are the difference of body shape. 2. The comparison of MD between men and women by BMI groups: Many measurements had significant differences between men and women at normal weight and overweight but underweight. Some measurements had significant differences only at a specific BMI group because the body shape difference between men and women is revealed clearly in the group. The comparison of MD between men and women by age groups: The measurements that show significant difference at more than four age groups were neck girth, chest girth, under-bust girth, waist girth, armscye girth, and foot length. The height and abdomen girth had a significant difference in the age range of 20's and 30's. There were measurements that increase MD with an increase in age; under-bust girth and lateral shoulder length for women and lateral shoulder length for men. This comparison of MD between men and women provide the correct guidelines for the use of SM.

• 한국생산제조학회지
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• 제8권4호
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• pp.106-111
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• 1999

This study discusses a non-contact optical technique electronic, electronic speckle pattern interferometry(ESPI) that is well suited for in-plane and out-of-plane deformation measurement Used as specimen which has the boundary condition of two clamped parallel edges composite material AS4/PEEK[30/-30/90]s was analyzed by ESPI to determined the characteristics of tensile and vibration. These are quantitativly compared with the result of FEM analysis. Finally the results of this study are briefly summarized as follows : (1) In the in-plane strain analysis by comparison of theoretical results with experimental results qualitatively we confirmed that measurement errors are within 3 % in case of accuracy (2) From comparison of experimental vibration modes with numerical vibration mode shapes by the FEM analysis quantitatively we confirmed that vibration mode measurement by the ESPI has high accuacy.

• Nuclear Engineering and Technology
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• 제56권7호
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• pp.2698-2703
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• 2024

A bilateral comparison was conducted between the International Atomic Energy Agency (IAEA) and the Korea Research Institute of Standards and Science (KRISS) to measure the absorbed dose to water in accelerator photon beams. KRISS served as a linking laboratory to compare the IAEA standard with the key comparison reference value (KCRV) of the BIPM.RI(I)-K6 program, in which KRISS participated in 2017. Two ionization chambers from the IAEA were used as transfer instruments for the comparison. Both laboratories measured the calibration coefficients of these instruments and calculated the ratios. The ratio of the KRISS standard to the KCRV was applied to obtain the degree of equivalence of the IAEA, along with its uncertainty. The largest deviation of the IAEA measurement from the KCRV was 3.4 mGy/Gy, significantly smaller than the expanded uncertainty of 10.7 mGy/Gy (k = 2, 95% level of confidence). This study demonstrates the equivalence of IAEA's measurement standard for accelerator photon beams to other primary standard dosimetry laboratories. It provides evidence for the satisfactory operation of IAEA's quality management system and enhances the international credibility of the IAEA SSDL network, particularly in high-energy accelerator photon beams from linear accelerators.

• 한국구조물진단유지관리공학회 논문집
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• 제4권4호
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• pp.191-199
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• 2000

Since a few decade ago, there has been a demand on the safety monitoring of civil infrastructures, such as bridges, in order to prevent possibly occurrable disaster due to human negligence. The main cause for a failure or collapse of structures is absolutely a structural crack. For the reason, it is necessary to monitor the propagation of a structural crack. But a crack in bridges is gradually propagating with the traffic loads through the long term. There are lots of sensors to monitor structural cracks on bridges, but much information about them was not given so far. Therefore, in this study, the experimental comparison for long-term monitoring sensors, especially, strain measurement sensors, in terms of duration, temperature dependency, accuracy was made extensively.

• 응용통계연구
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• 제19권3호
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• pp.565-578
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• 2006

의약학 분야에서는 두 집단에서 하나의 반복요인을 가지는 반복측정 자료가 많이 사용된다. 이 논문에서는 반복측정된 자료에서 두 군의 시간에 따른 반응값의 선형추세를 비교하여 두 집단간의 차이를 검정하는 방법을 제안한다. 각 개체에서 회귀계수를 추정하고 추정된 회귀계수들에 의해 생성된 표본을 가지고 이표본 t검정(unpaired t-test), 윌콕슨 순위합 검정(Wilcoxon rank sum test), 위치검정(placement test)으로 두 집단간 기울기의 차이를 검정한다. 모의실험(Monte Carlo Simulation)을 통해 실험유의수준(experimental significance level)과 검정력 (power)을 비교하였다.

• 한국전자통신학회논문지
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• 제15권3호
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• pp.405-412
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• 2020

서미스터 마운트는 전력의 변화에 따른 교정인자 값이 일정하여 정밀한 무선주파수 전력 측정에 사용하고 있다. 표준 마운트의 교정인자는 직류 대체법을 이용하여 전달표준과 직접 비교를 통해 10 MHz부터 1 GHz 대역까지 불확도 0.5 % 이하로 측정할 수 있다. 최근 직류 대체법 기반 정밀한 전력계의 산업계 보급으로 보다 간단하고, 빠른 측정이 가능함에 따라 동일한 불확도 수준의 단순 직접 비교 측정시스템을 설계하고, 부정합 오차의 분석을 통해 구성품의 최소 요구 사양을 제시하였다. 시스템 유효성 검증을 위해 시스템 불확도를 평가하였으며, 불확도 결과는 측정 주파수 대역에서 0.5 % 이내에서 잘 유지되었음을 보여준다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권6호
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• pp.313-316
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• 2006

A method for evaluation of the linearity of both the ratio error and phase angle error in the current transformer(CT) comparison measurement equipment has been developed by employing the standard resistors with negligible AC-DC resistance difference less than $10^{-5}$. The non-reactive standard resistors for the linearity check of the system are used as the external burden connected with the secondary of CT under test. These burdens consist of nine standard resistors, with the nominal resistance of $0.01{\Omega},\;0.1{\Omega},\;0.2{\Omega},\;0.4{\Omega},\;0.6{\Omega},\;1{\Omega},\;2{\Omega},\;4{\Omega}$, and $10{\Omega}$. For linearity check, the developed method has been applied in the CT comparison measurement equipment belonging to the industry.

• 한국수정란이식학회지
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• 제12권2호
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• pp.203-209
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• 1997

This study was carried out to compare the actual size(length and height) of ovaries, follicles and corpora lutea of Korean native cow with those on sonograms. We used 3 different probes(3.5 MHz abdominal probe, 6.5 MHz transvaginal probe and 5.0 MHz transrectal probe) and a calipher for measurements of ovaries, follicles and corpora lutea on sonograms and actual size. Under water immersion, 157 ovaries were scanned with 3 probes and measured in actual size and compared each other. The average height and width of ovaries of Korean native cows were 17.40$\pm$3.99 and 34.23$\pm$6.02mm, respectively. In comparison of height, length of ovaries and preovulation follicles, we found that image with a transvaginal probe was nearly the same as the actual size(p<0.01), but with an abdominal probe the image was appeared larger than the actual size. In measurement(diameter) of preovulation follicles the transvaginal probe was proven to be more accurate to the actual size than other probes and in corpus luteum measurement all probes were accurate. In the comparison of number of follicles by different size ranges, there was no statistical difference in the count of follicles over 10 mm in diameter between the transvaginal probe and naked eyes.