• 한국의학물리학회지:의학물리
• /
• 제14권3호
• /
• pp.161-166
• /
• 2003

다기능 X-선 선량계로서의 cadmium sulfide의 X-선에 대한 특성을 평가하기 위해 cadmium sulfide 기반의 X-선 선량계를 진공 증착법을 사용하여 제작하였으며 X-선 노출에 따른 cadmium sulfide의 반응을 측정하였다. Cadmium sulfide의 X-선 관전압, 관전류, 조사시간에 따른 전압의 변화를 측정하여 이를 분석하였다. X-선의 관전압에 따른 cadmium sulfide의 반응을 회귀분석을 통해 통계처리 한 결과 y=0.0995x-0.1146 ($R^2$=0.9595, $\sigma$=0.08, standard error=2%) 이고 X-선 관전류에 따른 cadmium sulfide의 출력신호를 분석한 결과 y=0.0439x+1.1891 ($R^2$=0.9021, $\sigma$=0.04, standard error=1.8%)였다. 또한 X-선 조사시간에 따른 cadmium sulfide의 반응을 같은 통계 방법으로 통계처리한 결과 y=8.2853x+5.5878 ($R^2$=0.7287, $\sigma$=0.06, standard error=1.9%) 였다. 결론적으로 cadmium sulfide의 X-선에 대한 반응은 X-선의 에너지가 증가됨에 따라 선형적으로 반응함을 알 수 있었으며 제작된 cadmium sulfide의 X-선의 다기능 선량계로서의 그 사용 가능성을 제시하고자 한다.

• KIEAE Journal
• /
• 제10권6호
• /
• pp.97-103
• /
• 2010

Sky simulator is a effective daylighting design tool that can evaluate three dimensional performance of lighting. Especially, the dome type sky simulator offer reliable and reproducible daylighting performance with different standard sky models. Recently, K university has developed the dome type sky simulator(sky dome) with the diameter of 6.5m and the height of 3.7m. The sky dome consists of a group of 145 large steel panels with 72 halogen lamps which are arranged in a circular array. The luminance distribution of the sky dome can be calibrated by changing the angle and the brightness of the lamps respectively. To allow more reliable prediction and evaluation of daylighting through the sky dome, It is essential to validate the sky luminance distribution of the sky dome. This study consider the validation of the comparisons between the measured and the calculated luminance values for the CIE standard overcast sky. Also, the error rate between the measured and the calculated luminance values were compared to the previous studies. The results indicated that the K university sky dome can reproduce reliable CIE standard overcast sky with the average relative error rate of 4.4% and root-mean-square error(RMSE) of 5.4%.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 추계학술대회 논문집 전기설비전문위원
• /
• pp.61-63
• /
• 2008

We established a system to evaluate the ratio error and phase angle error of electronic voltage transformer using high voltage capacitance bridge and standard capacitors. The uncertainty of evaluation system is about 0.005% in ratio error and 1.5 min in phase angel error.

• 한국품질경영학회:학술대회논문집
• /
• 한국품질경영학회 2006년도 추계 학술대회
• /
• pp.199-204
• /
• 2006

ANOVA is widely used for measurement system analysis. It assumes that the measurement error is normally distributed, which may not be seen in some industrial cases. In this study, the estimates of the measurement system variability and PTR (precision-to-tolerance ratio) are obtained by using weighted standard deviation for the case where the measurement error is non-normally distributed. The Standard Bootstrap method is used for estimating confidence intervals of measurement system variability and PTR. The point and confidence interval estimates for the cases with normally distributed measurement error are compared to those with non-normally distributed measurement errors through computer simulation.

• 한국군사과학기술학회지
• /
• 제26권2호
• /
• pp.139-148
• /
• 2023

Safety standards for long-range artillery ammunition test and training sites follow the US artillery shooting range safety zone standards. Although the South Korean geographical conditions of shooting ranges are different from those of the United States, there is no safety standard reflecting the South Korean topographical characteristics. Probable error associated with the shooting range, trajectory should be considered in establishing the safety standards. In this study, we present the safety standards for the ammunition testing site suitable for the Korean situation, with applying a concept of trajectory and probable error differed by ammunition type, which are currently confirmed by the South Korean Army's artillery shooting.

• 한국측량학회지
• /
• 제26권1호
• /
• pp.17-26
• /
• 2008

우리나라 1등 수준망은 1974년부터 1986년간 관측된 자료를 1987년 동시 조정된 바 있다. 이후, 국토지리정보원에서는 2001년부터 2006년까지 전자레벨과 바코드 함척을 이용하여 1등 수준망에 대한 직접수준측량 실시하였고, 본 연구는 이들 관측자료 분석 및 수준망 조정 결과이다. 우리나라 1등 수준망은 총 36개 노선으로 구성되어 있는데, 그 중 34노선이 11개 폐합 환을 구성한다. 1등 수준측량 관측자료 중 4개 노선은 1등 수준측량 허용 왕복차를 초과하였으며, 3개 수준환은 허용 환 폐합차를 초과하였다. 수준점간 왕복차의 표준오차(${\eta}_1$)는 $0.2{\sim}1.7mm/{\surd}km$, 환 폐합차의 표준오차(${\eta}_2$)는 $2.0mm/{\surd}km$로 IGA의 고정밀 수준측량기준을 충족하였다. 1등 수준망은 1점(수준원점) 고정방식에 의한 망조정이 수행되었으며, 기준 표준오차($\hat{{\sigma}_0}$)는 $1.8mm/{\surd}km$로, 1987년 1등 수준망 조정의 기준 표준오차($\hat{{\sigma}_0}$)보다 2배 향상된 결과이다.

• 치과방사선
• /
• 제29권2호
• /
• pp.417-422
• /
• 1999

Purpose : The aim of this study was to assess the validity of standard deviation of gray scale histogram in digital subtraction radiography as a test parameter for superimposition error. Materials and Methods : Twenty periapical radiographs were used as baseline images and they were copied to exclude the influence of exposure geomety and contrast differences. These subsequent images were linearly displaced by 0.1-0.5 mm in the x-. y- and xy-directions, rotated by 0.5-3° and distorted by angular contraction of 1-5° in x- and y-axis before subtraction. The standard deviations of gray levels in the subtraction images were obtained and paired t-tests were performed. Pearson correlation coefficients(r) were calculated between the standard deviations and the superimposition errors. Results : Linear displacement showed high correlation coefficients of 0.997, 0.997 and 0.995 in x-. y- and xy-axis respectively. Statistically significant different standard deviation existed among all linearly displaced groups(p<0.05). Distortion showed relatively low correlation coefficients of 0.982 and 0.959 in x- and y-axis. The standard deviations between the two distortion groups were statistically significant different(p<0.05). Conclusion : Standard deviation of gray level distribution in digital subtraction images is satisfactory but not perfect similarity measure to assess the superimposition errors.

• Journal of Positioning, Navigation, and Timing
• /
• 제10권2호
• /
• pp.153-158
• /
• 2021

In order to mitigate the vulnerability of the satellite navigation system against radio frequency interference, South Korea has been developing advanced terrestrial navigation system (eLoran) technology since 2016. The eLoran system synchronizes the transmission time of the pulse used in the existing Loran-C system with UTC and transmits correction information that can improve the position error. The eLoran system is known to reduce the position error of about 460 m of the existing Loran-C system to 20 m, and for this, the transmitter must be able to transmit eLoran signals according to more stringent standards. For this reason, an international standard that further developed the Loran-C signal standard established by US Coast Guard was established by Society of Automotive Engineers (SAE) International. In this paper, based on the analysis of the SAE9990 document, the international standard for eLoran transmission signals, a standard inspection process was produced to check whether the eLoran transmitter is transmitting signals in accordance with the standard.

• 한국태양에너지학회 논문집
• /
• 제32권2호
• /
• pp.74-86
• /
• 2012

For the improvement of environmental comfort in the buildings with the blind control, the objective of this study is to prevent the direct glare caused by the daylight inlet. During the process of solar profile prediction, time are significant factors that may cause error and glare during the blind control. This research proposes and evaluates the correction and control method to minimize prediction error. For the local areas with different longitude and local standard meridian, error occurred in the process of the time conversion from local standard time to apparent solar time. In order to correct error in time conversion, apparent solar time should be recalculated after adjusting the day of year and the equation of time. To solve the problems by the potential time errors, control method is suggested to divide the control sections using the calibrated fitting-curve and this method is verified through simulations. The proposed correction and control method, which considered potential time errors by loop lop leap years, could solve the problems about direct glare caused by daylight inlet on the work-plane according to the prediction errors of solar profile. And also these methods could maximize daylight inlet and solar heat gain, because the blocked area on windows could be minimized.

• Ocean and Polar Research
• /
• 제30권2호
• /
• pp.149-158
• /
• 2008

The characteristic analysis of the estimated population parameters, i.e., standard deviation and error bound of coastal pollutant concentrations (hereafter PC, i.e., COD, TN, and TP concentrations), was carried out by using environmental data with different sampling frequency in Lake Shihwa and Incheon coastal zone. The results clearly show that standard deviation of the PC increases as its mean value increases. The error bounds of the annual mean values based on seasonally measured DO concentrations and PC data in Incheon coastal zone were estimated as ranges 2.26 mg/l, $0.68{\sim}0.86\;mg/l$, $0.62{\sim}0.80\;mg/l$, and $0.074{\sim}0.082\;mg/l$, respectively. In terms of annual mean of the DO concentration and PC in Lake Shihwa, the error bounds based on monthly measured data from 1997 to 2003 were also estimated as ranges 4.0 mg/l, 3.0 mg/l, $0.5{\sim}1.0\;mg/l$, and 0.05 mg/l, respectively. The error bound on the basis of real-time monitoring data is $7{\sim}13%$ only as compared to that of monthly measured data.