• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.102-102
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• 2016

일반적으로 수자원분야에서 사용되는 기초 자료 중 하나인 유량측정 성과는 설계홍수량 산정, 지점의 수위-유량 관계곡선식 산정 등 유역의 이 치수를 위한 설계나 장 단기 계획을 수립하기 위한 기초자료로서 사용되어지고 있으며, 2차원 및 3차원 수치해석을 위한 입력 자료로 사용되고 있다. 유량측정의 성과는 이렇듯 다양한 방면으로 활용되어지고 있는 반면 현재 국내에서는 측정의 성과에 대한 신뢰성을 나타낼 수 있는 지표가 제시되고 있지 않은 상황이다. ISO(International Organization for Standardization) 및 BIPM, IFCC 등 6개 기구는 공동으로 측정 불확도 산정 지침서(GUM, Guide to the expression of Uncertainty in Measurement, 1993)을 제시하였고, 최근 WMO에서는 GUM 표준안을 하천 유량 측정 불확도 산정방법으로 공인하고 있다(JCGM 100, 2008). 이에 따라 본 연구에서는 최근 유량 측정에 활발하게 사용되고 있는 ADCP의 유량 측정 성과에 대한 불확도를 GUM 표준안 기반으로 평가하고자 한다. ADCP의 측정 방법은 고정측정 방식이고, 유속-면적법으로 계산된 유량에 대한 측정 불확도를 평가하였다. 실험은 실규모에서 유량을 제어할 수 있는 건설기술연구원 하천실험센터에서 수행되었고, 사용된 유속 측정 장비는 SonTek사의 micro-ADV와 ADCP M9을 사용하였으며, ADV로 측정된 결과를 참값으로 가정한 후 실험 및 분석을 수행하였다. GUM 표준안 기반의 불확도 평가를 위해 사용된 관계식 및 불확도 요인들은 선행 연구들을 기반으로 하되, 본 실험을 통해 분석된 수치로 변경하여 최종적인 ADCP 유량 산정 불확도를 평가하였다. 본 연구에서는 고정측정 방식 ADCP의 유량 측정 결과를 GUM 표준안에 적용하여 불확도를 평가하였으며, 추가적인 연구를 진행하여 일반적으로 사용하고 있는 이동측정 방식 ADCP의 유량 측정 결과에 대한 불확도를 평가할 수 있을 것으로 기대되며, 이러한 결과는 설계 홍수량 산정이나 수위-유량 관계 곡선식 산정 등 다양한 분야에 적용할 수 있을 것으로 사료된다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.1
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• pp.73-78
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• 2010

Estimation of tensile properties measurement uncertainty of material was carried out. Sources of uncertainty affecting the measurement of tensile properties were classified and analyzed. The models for uncertainty evaluation of measurands to be determined from tensile test, such as elastic modulus, yield strength and tensile strength, were suggested and derived from the mathematical relations, corresponding to the respective measurands, and the measuring quantities by calculating each sensitivity coefficient of the quantities. Based on these models, the uncertainty of the tensile properties was evaluated from the experimental data of SUS316LN determined according to ISO 6892.

• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.169-178
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• 2011

BACKGROUND: This study aimed to estimate the measurement uncertainty associated with determination of cadmium and lead from tomato paste by ICP/MS. The sources of measurement uncertainty (i.e. sample weight, final volume, standard weight, purity, molecular weight, working standard solution, calibration curve, recovery and repeatability) in associated with the analysis of cadmium and lead were evaluated. METHODS AND RESULTS: The guide to the expression of uncertainty was used for the GUM (Guide to the expression of Uncertainty in Measurement) and Draft EURACHEM/CITAC (EURACHEM: A network of organization for analytical chemistry in Europe/Co-Operation on International Traceability in Analytical Chemistry) Guide with mathematical calculation and statistical analysis. The uncertainty components were evaluated by either Type A or Type B methods and the combined standard uncertainty were calculated by statistical analysis using several factors. Expected uncertainty of cadmium and lead was $0.106{\pm}0.015$ mg/kg (k=2.09) and $0.302{\pm}0.029$ mg/kg (k=2.16), on basis of 95% confidence of Certified Reference Material (CRM) which was within certification range of $0.112{\pm}0.007$ mg/kg for cadmium (k=2.03) and $0.316{\pm}0.021$ mg/kg for lead (k=2.01), respectively. CONCLUSION(s): The most influential components in the uncertainty of heavy metals analysis were confirmed as recovery, standard calibration curve and standard solution were identified as the most influential components causing uncertainty of heavy metal analysis. Therefore, more careful consideration is required in these steps to reduce uncertainty of heavy metals analysis in tomato paste.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2004.06a
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• pp.32-38
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• 2004

• Analytical Science and Technology
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• v.16 no.6
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• pp.475-482
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• 2003

Uncertainty of final measurement results considering main uncertainty sources being in dioxin analysis of a blood sample was estimated. 'The Guide to the Expression of Uncertainty in Measurement' was suggested for accomplishment of this study. After uncertainties for the 11 compounds detected in this experiment of the 17 target compounds of dioxin and furan were calculated considering the uncertainty sources of each step, uncertainty for the total dioxin concentration was estimated by combining these values. The concentration of dioxin in blood sample was expressed as $0.0746{\pm}0.0074pg$ I-TEQ/g weight or $20.68{\pm}2.04pg$ I-TEQ/g lipid, including the uncertainty values obtained in this way. The former expression indicates the conversion concentration into the sample weight and the latter one indicates the conversion concentration into the lipid weight. The quality of measured analytical results could be assured quantitatively by estimating uncertainty of measurement results and showing the range of measurand.

• Korean Journal of Food Science and Technology
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• v.41 no.3
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• pp.258-264
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• 2009

The principal objective of this study was to estimate the measurement uncertainty associated with determination of deoxynivalenol (DON), a mycotoxin generated by Fusarium strain, in food. In service of this goal, wheat as a food matrix was analyzed via high performance liquid chromatography-ultraviolet (HPLC-UV) detection using an immunoaffinity column for clean-up. The uncertainty sources in the measurement process were identified by sample weight, final volume, and sample concentration in extraction volume with components including standard stock solution, working standard solution, 5 standard solutions, calibration curve, matrix, and instrument. The expanded uncertainty for DON at a concentration of 300 ${\mu}g/kg$ was estimated as 71.62 ${\mu}g/kg$ using a coverage factor of two, which provides a confidence level of approximately 95%. The most influential component in the uncertainty sources was the recovery of the wheat matrix, followed by the calibration curve. These results indicate that all efforts may be directed toward reducing the uncertainties of the recovery of the wheat matrix and the calibration curve to obtain a reliable HPLC-UV method for DON analysis in wheat.

• Journal of the Korean Society for Railway
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• v.17 no.4
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• pp.223-227
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• 2014

The brake pad is one of the basic brake elements of a railway vehicle. It accomplishes braking action by friction between a pad and a brake disc. Because the brake pad must endure specified high pressure, the compressive strength is managed as the main performance factor. The standards for measuring the compressive strength of brake pads are KRS, KRCS, and KRT. These standards specify the size of the test piece for measuring compressive strength as $20mm{\times}10mm{\times}15mm$ ($W{\times}D{\times}H$). To reduce the uncertainty of the compressive strength, factors of uncertainty were analyzed. The results show that changing the dimensions of the cross section was useful to reduce the uncertainty. The uncertainty due to the new cross-sectional dimension shows the effectiveness of reducing uncertainty.

• The Journal of the Acoustical Society of Korea
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• v.42 no.2
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• pp.143-151
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• 2023

In this paper, a method for evaluating the measurement uncertainty is proposed when measuring of floor impact sound insulation of buildings using standard heavy impact source. In addition to the effect of repeated measurements, several other factors such as measurement location, impact location, equipment used for sound pressure measurement, and heavy impact source, were considered. A mathematical model for the average maximum impact sound level and the uncertainty evaluation method for each factor were proposed. The present proposed method was applied to measurement results to evaluate the average maximum impact sound pressure level and the measurement uncertainty.

• The Journal of the Acoustical Society of Korea
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• v.23 no.2
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• pp.90-102
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• 2004

According to the Mutual Recognition Arrangement (MRA), the calibration and/or test laboratories should satisfy the management and technical requirements ISO 17025 or equivalent. Chapter 5, Section 5.10.4 of the technical requirement of ISO 17025 suggests the required informations for calibration certificates, one of them is to state the uncertainty of measurement. The uncertainties of measurement in reciprocity calibration of standard laboratory microphone were calculated. The expanded uncertainties for 1 and 1/2 inch microphones were 0.03 dB in the middle frequency range and they increased up to 0.10 dB and 0.11 dB at 20 Hz, 0.07 dB and 0.08 dB at high frequency, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.2 s.117
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• pp.166-176
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• 2007

Measurement uncertainty assessment is very important in measurement and calibration. RRL provides antenna calibration services for EMI test. Reliability of EMI test depends on accurate antenna calibration. Antenna calibration results have to be accompanied with measurement uncertainty for its better reliability. In the late of 2005, CISPR issued the CISPR/A/644/C which describes the antenna calibration and measurement uncertainty. In this paper, on the basis of CISPR/A/644/C, we provide the measurement uncertainty values for dipole antenna calibration at the Calibration Test Site(CALTS) of Icheon. The antenna calibration method is 3-antenna height-scanning-averaging method, which measures the free-space antenna factor. We also considered all uncertainty sources that can affect measurement results during calibration.