• 제목/요약/키워드: Expanded uncertainty

검색결과 197건 처리시간 0.032초

플라스틱재료의 기계적 특성시험 불확도추정에 대한 고찰 (A Study on Estimation uncertainty of measurement in mechanical characteristic exam for Plastic materials)

  • 김원경;권성태;김정남
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2003년도 추계학술대회 논문집(III)
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    • pp.301-306
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    • 2003
  • Recently, uncertainty of measurement became a major concern for the people working on the laboratory evaluation and accreditation. 'uncertainty of measurement is a parameter associated with the result of a measurement that characteristics the dispersion of the value that could reasonably be attributed to the measured.' This study analysed how to estimate uncertainty of measurement in mechanical characteristic exam for Plastic material. its uncertainty was estimated according to International Organization for Standardization(ISO), they were named to A type uncertainty, B type uncertainty, combined standard uncertainty, and expanded uncertainty. We obtained that the combined standard uncertainty was 0.96697 MPa and the expanded uncertainty was 2.291MPa.

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버어리종 담배 중 질산성 질소에 대한 측정불확도 (Uncertainty of Measurement in Nitrate Analysis from Burley Leaf Tobacco)

  • 이정민;이경구;한상빈
    • 한국연초학회지
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    • 제27권2호
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    • pp.226-234
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    • 2005
  • The uncertainty of measurement in nitrate from burley leaf tobacco by continuous-flow analysis method was evaluated following internationally accepted guidelines. The sources of uncertainty associated with the analysis of nitrate were weight of standard and sample, purity of standard, dilution of standard solution, calibration curve, water content, etc. The calculation of uncertainty based on the GUM(Guide to the Expression of Uncertainty in Measurement) and EURACHEM/CITAC Guide. An expanded uncertainty was obtained by multiplying the combined standard uncertainty with a coverage factor (k) calculated from the effective degree of freedom. The concentration of nitrate from burley leaf tobacco was $2.09\%$ and the expanded uncertainty by multiplying by the coverage factor(k, 2.20) was $0.13\%\;at\;a\;95\%$ confidence level.

스피닝 로터 게이지 교정 불확도 (Calibration uncertainty of a spinning rotor gauge)

  • 홍승수;임인태;신용현;정광화
    • 한국진공학회지
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    • 제12권1호
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    • pp.7-15
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    • 2003
  • 스피닝 로터 게이지는 표준기관의 고진공 국제비교에 전달표준기로 상용되고 있으며, 고진공 국가표준기인 동적교정장치를 이용하여 스피닝 로터 게이지를 교정하였다. 교정 결과의 불확도를 국제표준화기구에서 권고한 A형 불확도, B형 불확도, 합성표준불확도, 확장불확도 등으로 구분하여 평가하는 방법을 제시하였다. 이 방법에 따라 평가한 스피닝 로터 게이지의 합성표준불확도는 $1.8007\times10^{-5}$ Pa ~$4.8422\times10^{-5}$ Pa 이었다.

품질통계에서 자유도 개념 및 유형 (Concept and Type for Degree of Freedom in Quality Statistics)

  • 최성운
    • 대한안전경영과학회지
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    • 제9권6호
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    • pp.193-196
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    • 2007
  • This paper presents real examples of quality statistics for users to easily understand the concept and purpose for obtaining the degree of freedom. Moreover degree of freedom by Satterwaite can be used for linear combinations of unbiased variance. Finally effective degree of freedom by Welch-Satterthwaite is applicable to obtain expanded uncertainty considering type A and type B uncertainty.

하이브리드 로켓 모터에 대한 연소 실험 측정 불확도 (Combustion Experiment Measurement Uncertainty for Hybrid Rocket Motor)

  • 김수종;문희장;김진곤
    • 한국항공운항학회지
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    • 제19권1호
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    • pp.7-14
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    • 2011
  • In this study, the measurement uncertainty of combustion experimental system and experimental parameters for hybrid rocket were evaluated by B type evaluation method. The measurement uncertainty of all experimental parameters was lower than 3%. The highest value of expanded uncertainty was characteristic velocity efficiency with 2.83% and the expanded uncertainty of regression rate which is the design and performance parameter was indicated to 0.03%. These results shown that the reliability of hybrid combustion system was located within allowed limits.

소닉노즐의 유량측정 불확도 평가 (Evaluation of Flow Measurement Uncertainty of Sonic Nozzle)

  • 최해만;박경암;최용문;오연균;윤병로
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집E
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    • pp.601-606
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    • 2001
  • Measurement uncertainty should be evaluated according to ISO/IEC 17025. In Flow measurement area, uncertainty evaluation scheme was applied to the reference flow meter, sonic nozzle. Uncertainty was calculated by evaluating various uncertainty factors affected in flow measurement. The expanded uncertainty of the sonic nozzle was 0.21 % (confidence level of 95 %). This evaluation example will be useful in flow measurement uncertainty determination of other flow meters.

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새로운 개념의 피스톤 푸루버 개발 및 불확도 평가 (Development and Uncertainty Evaluation of New Piston)

  • 최해만;박경암
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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    • pp.354-359
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    • 2002
  • The new piston prover was developed and the flow measurement uncertainty of this piston prover was evaluated according to ISO/IEC 17025. The laser interferometer was employed to measure accurately the testing time. Uncertainty was calculated with evaluation of various uncertainty factors affected in flow measurement. The expanded uncertainty(U) of the piston Over was $1.3{\times}10^{-3}$ (at the confidence level of $95\%$). This evaluation example will be useful in flow measurement uncertainty determination of other gas flow measurement system.

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광학 현미경을 이용한 선표준물 측정 시스템 개발 (Development of Line Standards Measurement System Using an Optical Microscope)

  • 김종안;김재완;강주석;엄태봉
    • 한국정밀공학회지
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    • 제26권8호
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    • pp.72-78
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    • 2009
  • We developed a line standards measurement system using an optical microscope and measured two kinds of line standards. It consists of three main parts: an optical microscope module including a CCD camera, a stage system with a linear encoder, and a measurement program for a microscopic image processing. The magnification of microscope part was calibrated using one-dimensional gratings and the angular motion of stage was measured to estimate the Abbe error. The threshold level in line width measurement was determined by comparing with certified values of a line width reference specimen, and its validity was proved through the measurement of another line width specimen. The expanded uncertainty (k=2) was about 100 nm in the measurements of $1{\mu}m{\sim}10{\mu}m$ line width. In the comparison results of line spacing measurement, two kinds of values were coincide within the expanded uncertainty, which were obtained by the one-dimensional measuring machine in KRISS and the line standards measurement system. The expanded uncertainty (k=2) in the line spacing measurement was estimated as $\sqrt{(0.098{\mu}m)^2+(1.8{\times}10^{-4}{\times}L)^2}$. Therefore, it will be applied effectively to the calibration of line standards, such as line width and line spacing, with the expanded uncertainty of several hundreds nanometer.

표준 영상에 의한 FFT 기반 상호상관 PIV 알고리즘의 불확도 해석 (Uncertainty Analysis of Cross-Correlation Algorithm based on FFT by PIV Standard Images)

  • 이석종;최중근;성재용;황태규;도덕희
    • 한국가시화정보학회지
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    • 제3권2호
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    • pp.71-78
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    • 2005
  • Uncertainty introduced by a cross-correlation algorithm based on FFT has been investigated using PIV standard images. The standard images were generated by the Monte Carlo simulation method. Both bias and random errors from the velocity vector have been analyzed with regard to the particle diameter, displacement, and the number of particles. The uncertainty of velocity is evaluated based upon the IS0/IEC standard. As a result, a total error of $0.26\%$ is included in the PIV cross-correlation algorithm. In addition, the uncertainty budget is presented, where the effect of the above three variables is examined. According to the budget, the variation of the number of particles within the interrogation window mainly contributes to the combined standard uncertainty of the real measured velocity field when excluding the effect of errors by the experiments itself. Finally, the expanded uncertainty is found to be about $12\%$ at the $95\%$ confidence level.

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