• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.1
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• pp.65-74
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• 2018

The aim of this study was to obtain the traceability of the software used to analyze lateral cephalometry and to calculate the uncertainty of the measurements. Furthermore, this study aimed to provide a basis for obtaining standard references for measurement values for orthodontic treatment in children. Cephalometric data were collected from 100 children diagnosed with class I malocclusion between the ages 6 to 13 years who visited the pediatric dentist at Seoul National University Dental Hospital. To ensure traceability, a phantom device was created. Correction values were calculated by measuring the length and angle of the phantom device using the software. Type A uncertainty was calculated by obtaining the standard deviation of cephalometric measurements of 100 persons and the standard error of repeated measurements. Determination of the type B uncertainty was induced by minimum resolution and the position of the head. Using these, the combined standard uncertainty was obtained and the expanded uncertainty was calculated. The results of this study confirm that the currently used software has high accuracy and reliability. Furthermore, the uncertainty of orthodontic measurements in Korean children aged 6 to 13 years was calculated, and distribution range for class I malocclusion with 95% confidence interval was suggested.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.1
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• pp.72-78
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• 2009

We have developed a current range extension method to obtain the ratio error and phase displacement of a current transformer (CT) by using absolute evaluation method and two different CTs. The method was applied to CTs under test with the current ratios in the range of 5,000 A / 1 A - 20,000 A / 1 A. The ratio error and phase displacement of the CT under test obtained in this study are consistent with those measured at the national institute in Germany using the same CT under test within an expanded uncertainty (k = 2) in the overall current ratios.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.10
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• pp.1385-1392
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• 2003

An electromagnetic flowmeter(EMF) was developed and its characteristics were compared with a commercial EMF. The developed EMF was designed as the 100 mm nominal diameter. A signal processing circuit was also developed for generating the magnetic field and converting the flow signal to flowrate and flow quantity. In order to obtain a more stable and reliable flow signal, the double magnetizing frequency was adopted for magnetizing the coil of the EMF. For the characterization of the developed EMF, the uncertainty of calibrator was estimated within $\pm$0.5 %. The evaluation procedure of the uncertainty followed the ISO Guide to the Expression of Uncertainty in Measurement. It was found that the flow signals between the electrodes were about $\pm$60-$\pm$300$\mu$V, which were sufficient for the discrimination of flowmeter and the protection of noise. The test results against the calibrator showed the good linearity in the range of 3 ㎥/h and 70 ㎥/h. A commercialized design of the EMF based on the current study will be technically more competitive in domestic and foreign market.

• KIEAE Journal
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• v.15 no.6
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• pp.5-10
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• 2015

Purpose: To evaluate the economic performance of grid-connected photovoltaic system in residential house, household electricity bill policy of Korea Electric Power Corporation (KEPCO) must be applied precisely, and market tendency and uncertainty of system also need to be considered. In this study, to evaluate the economic feasibility of PV system, we measured PV power generation and electricity consumption of six of Green home in Daejeon through web based remote monitoring system. Method: We applied Monte-Carlo simulation based on life cycle cost analysis, to reflect an uncertainty of main factor in economic feasibility evaluation of photovoltaic system. Result: First, with deterministic analysis, the difference of NPV of cumulative financial savings among households varied from -3,310 ~ 24,170 thousand won, portraying notably big range. Also the possibility of getting the same result was 50% when applying uncertainty. Second, the higher electricity consumption is, the more economic feasibility of photovoltaic system increases because KEPCO uses progressive taxation in household electricity bill policy. Third, The contribution to variance of electricity price increases in NPV varied from 98.5% to 99.9%. While the inflation rate and annual degradation contributed very little to none.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1438-1441
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• 2005

To establish of standard technique of nano-length measurement in 2D plane, new AFM system has been designed. In this system, measurement uncertainty is dominantly affected by the Abbe error of XY scanning stage. No linear stage is perfectly straight; in other words, every scanning stage is subject to tilting, pitch and yaw motion. In this paper, an AFM system with minimum offset of XY sensing is designed. And XY scanning stage is designed to minimize rotation angle because Abbe errors occur through the multiply of offset and rotation angle. To minimize the rotation angle optimal design has performed by maximizing the stiffness ratio of motion direction to the parasitic motion direction of each stage. This paper describes the design scheme of full AFM system, especially about XY stage. Full range of fabricated XY scanner is $100um\times{100um}$. And tilting, pitch and yaw motion are measured by autocollimator to evaluate the performance of XY stage. Using this AFM system, 3um pitch specimen was measured. As a result, the uncertainty of total system has been evaluated.

• Nuclear Engineering and Technology
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• v.26 no.3
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• pp.389-400
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• 1994

The predictability of KAERI version of RELAP5/MOD3 on reflood peak cladding temperature during large break loss-of-coolant accident is assessed against 18 test runs in FLECHT SEASET test data. The associated uncertainty is statistically quantified. The selected test runs include a gravity feed test and several forced feed tests with wide range of the parameters such as flooding rate, system pressure, initial clad temperature, rod bundle power. The results show that the code under-predicts the peak cladding temperature by 7.56 K on average. The upper limit of the associated uncertainty at 95% confidence level is evaluated to be about 99 K, It including the bias due to the under-prediction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.3
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• pp.520-528
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• 2001

This paper investigates a resonant microaccelerometer that measures acceleration using a built-in micromechanical resonator, whose resonant frequency is changed by the acceleration-induced axial force. A set of design equations for the resonant microaccelerometer has been developed, including analytic formulae for resonant frequency, sensitivity, nonlinearity and maximum stress. On this basis, the sizes of the accelerometer are designed for the sensitivity of 10$^3$Hz/g in the detection range of 5g, while satisfying the conditions for the maximum nonlinearity of 5%, the minimum shock endurance of 100g and the size constraints placed by microfabrication process. A set of the resonant accelerometers has been fabricated by the combined use of bulk-micromachining and surface-micromachining techniques. From a static test of the cantilever beam resonant accelerometer, a frequency shift of 860Hz has been measured for the proof-mass deflection of 4.3${\pm}$0.5$\mu\textrm{m}$; thereby resulting in the detection sensitivity of 1.10${\times}$10$^3$Hz/g. Uncertainty analysis of the resonant frequency output has been performed to identify important issues involved in the design, fabrication and testing of the resonant accelerometer.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.8
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• pp.203-212
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• 1999

This paper describes a deadweight force standard machine with the weight change mechanism which can be used as a primary force standards at a national metrology institute. Since commercial deadweight force machine can generate forces by hanging weights to the weight supporter serially, force steps from deadweight force measuring devices of each having different capacity. In order to increase the force steps, we have specially designed a weight mechanism in which the machine can select the necessary weights and generate the load by hanging the selected weights to the weight supporter. The machine can generate 속 force of the range of 2 kN to 110 kN with force step of 1 kN. All weights have been accurately compensated and calibrated by a mass comparator and its standard uncertainty is less than 2.2 ${\times}\;10^{-6}$. The relative expanded uncertainty of the machine is 1.3 ${\times}\;10^{-5}$.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.1
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• pp.47-57
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• 2018

This study implemented the rainfall-runoff analysis of the Mekong River basin using the SWAT (Soil and Water Assessment Tool). The runoff analysis was simulated for 2000~2007, and 11 parameters were calibrated using the SUFI-2 (Sequential Uncertainty Fitting-version 2) algorithm of SWAT-CUP (Calibration and Uncertainty Program). As a result of analyzing optimal parameters and sensitivity analysis for 6 cases, the parameter ALPHA_BF was found to be the most sensitive. The reproducibility of the rainfall-runoff results decreased with increasing number of stations used for parameter calibration. The rainfall-runoff simulation results of Case 6 showed that the RMSE of Nong Khai and Kratie stations were 0.97 and 0.9, respectively, and the runoff patterns were relatively accurately simulated. The runoff patterns of Mukdahan and Khong Chaim stations were underestimated during the flood season from 2004 to 2005 but it was acceptable in terms of the overall runoff pattern. These results suggest that the combination of SWAT and SWAT-CUP models is applicable to very large watersheds such as the Mekong for rainfall-runoff simulation, but further studies are needed to reduce the range of modeling uncertainty.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.9
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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.