• 한국터널지하공간학회 논문집
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• 제5권4호
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• pp.337-348
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• 2003

밀장전한 암반 발파공에서 화약 폭발시 발생하는 고압의 폭굉압력 전파메카니즘을 충격파 이론을 적용하여 규명하고 전달된 발파압력 산정식을 유도하였다. 유도된 발파압력 산정식은 폭굉파속도, 단열지수, 화약밀도, Hugoniot 상수, 암반밀도의 함수였다. 에멀젼 화약과 서울 화강암의 특성시험을 시행하여 각 특성치의 확률분포를 정의하고 발파압력 산정식에 적용하여 발파압력의 확률분포를 산출하였다. 화약 특성치와 암반 특성치의 확률분포는 정규분포를 나타냈으며 따라서 발파압력의 확률분포도 정규분포로 추정되었다. 발파압력에 대한 매개변수분석을 시행한 결과 폭굉파속도가 발파압력에 가장 크게 영향을 미쳤다. 또한 이런 특성치의 불확실성이 발파압력의 불확실성에 미치는 영향을 분석하였다. 분석결과 암반특성치의 불확실성이 화약특성치보다 더 크게 영향을 미쳤다. 비록 매개변수분석에서 폭굉파속도가 발파압력에 가장 크게 영향을 미치는 요소이지만 암반특성치의 불확실성이 폭굉파속도의 불확실성보다 더 크기 때문에 발파압력은 후자보다 전자에 의해서 더 크게 영향을 받는다.

• 한국암반공학회:학술대회논문집
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• 한국암반공학회 2005년도 춘계학술발표회 논문집
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• pp.81-95
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• 2005

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.391-398
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• 2004

The propagation mechanism of a detonation pressure with fully coupled charge is clarified and the blasting pressure propagated in rock mass is derived from the application of shock wave theory. Probabilistic distribution is obtained by using explosion tests on emulsion and rock property tests on granite in Seoul and then the probabilistic distribution of the blasting pressure is derived from their properties. The probabilistic distributions of explosive properties and rock properties show a normal distribution so that the blasting pressure propagated in rock can be also regarded as a normal distribution. Parametric analysis was performed to pinpoint the most influential parameter that affects the blasting pressure and it was found that the detonation velocity is the most sensitive parameter. Moreover, uncertainty analysis was performed to figure out the effect of each parameter uncertainty on the uncertainty of blasting pressure. Its result showed that uncertainty of natural rock properties constitutes the main portion of blasting pressure uncertainty rather than that of explosive properties.

• 터널과지하공간
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• 제15권6호
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• pp.441-451
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• 2005

RMR 암반분류법은 구간별 RMR값 산정시 일정 범위의 값을 채택함으로 인해 불확정성을 피할 수 없다. 이에 본 연구에서는 각 파라미터별로 연속적인 RMR 값을 평가하여 확률밀도함수그래프를 산정하고 모든 경우의 수에 대한 몬테카를로 시뮬레이션과 통계추론을 통해 RMR 산정의 불확정성을 정량적으로 평가하였다. 또한 RMR 산정의 불확정성을 실무에 적용하기 위하여 신뢰수준별 수정 RMR 암반등급 산정표를 제시하였으며, 이를 근간으로 RMR 암반분류의 표준지보패턴 및 지보재 설계 수행절차를 제안하였다.

• Structural Monitoring and Maintenance
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• 제9권1호
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• pp.59-80
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• 2022

In the present study, the objective is to detect the structural damages using the responses obtained from the sensors at the optimal location under uncertainty conditions. Reducing the error rate in damage detection process due to responses' noise is an important goal in this study. In the proposed algorithm for optimal sensor placement, the noise of responses recorded from the sensors is initially reduced using the principal component analysis. Afterward, the optimal sensor placement is obtained by the damage detection equation based sensitivity analysis. The sensors are placed on degrees of freedom corresponding to the minimum error rate in structural damage detection through this procedure. The efficiency of the proposed method is studied on a truss bridge, a space dome, a double-layer grid as well as a three-story experimental frame structure and the results are compared. Moreover, the performance of the suggested method is compared with three other algorithms of Average Driving Point Residue (ADPR), Effective Independence (EI) method, and a mass weighting version of EI. In the examples, young's modulus, density, and cross-sectional areas of the elements are considered as uncertainty parameters. Ultimately, the results have demonstrated that the presented algorithm under uncertainty conditions represents a high accuracy to obtain the optimal sensor placement in the structures.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1659-1662
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• 2003

The mass measurement of solid density standards using weight exchanger is described. KRISS(Korea Research Institute od Standards and Science) has several solid density standards. Their mass have been measured manually only using a mass comparator(Mettler, 1kg - 0.01mg). However, the uncertaity of the manual mass measurement is up to 300 microgarm much more than 32 microgram of advanced NMIS(National Metrology Institutes) for 1 kg silicon sphere which is primary density standards due to an eccentric error and buoyancy correction error. The new system with a weight exchanger is designed and built to improve the measurement accuracy. It comprises a weight exchager, a mass comparator, air density instruments, and application program for automatic measurement. It is evaluated by measuring several elements in an air tight chamber to verify the performance of it.

• Mass Spectrometry Letters
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• 제5권2호
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• pp.57-61
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• 2014

A gravimetric standard addition method combined with internal standard calibration has been successfully developed for the accurate analysis of total arsenic in a laver candidate reference material. A model equation for the gravimetric standard addition approach using an internal standard was derived to determine arsenic content in samples. Handlings of samples, As standard and internal standard were carried out gravimetrically to avoid larger uncertainty and variability involved in the volumetric preparation. Germanium was selected as the internal standard because of its close mass to the arsenic to minimize mass-dependent bias in mass spectrometer. The ion signal ratios of $^{75}As^+$ to $^{72}Ge^+$ (or $^{73}Ge^+$) were measured in high resolution mode ($R{\geq}10,000$) to separate potential isobaric interferences by high resolution ICP/MS. For method validation, the developed method was applied to the analysis of arsenic content in the NMIJ 7402-a codfish certified reference material (CRM) and the result was $37.07mg{\cdot}kg^{-1}{\pm}0.45mg{\cdot}kg^{-1}$ which is in good agreement with the certified value, $36.7mg{\cdot}kg^{-1}{\pm}1.8mg{\cdot}kg^{-1}$. Finally, the certified value of the total arsenic in the candidate laver CRM was determined to be $47.15mg{\cdot}kg^{-1}{\pm}1.32mg{\cdot}kg^{-1}$ (k = 2.8 for 95% confidence level) which is an excellent result for arsenic measurement with only 2.8 % of relative expanded uncertainty.

• 분석과학
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• 제32권6호
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• pp.225-232
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• 2019

Traceability establishment in chemical measurements is a like a linkage established through an unbroken chain from the measured results to the international system (SI) of units. The primary process for traceability establishment is the purity assignment of a target material to be measured. In this study, we studied the purity assignment of 17α-hydroxyprogesterone (17-OHP). The presence of 17-OHP is indicative of congenital adrenal hyperplasia (CAH) and it builds up due to the deficiency of 21-hydroxylase and 11β-hydroxylase enzyme in the human blood. The purity assignment of 17-OHP was performed by the mass balance method, in which the impurities are categorized into four classes: total related structural impurities, water, residual organic solvents, and nonvolatiles/inorganics. The total related structural impurities were characterized by HPLC-UV; water content was determined by Karl-Fisher coulometer; and the total residual solvents and nonvolatiles/inorganics were determined by TGA. The purity of 17-OHP from a commercial manufacturer was calculated as 993.30 mg/g, and the expanded uncertainty was 0.58 mg/g. The proposed method was validated by uncertainty evaluation and comparing with the actual value of purity.

• 한국추진공학회지
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• 제22권3호
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• pp.14-20
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• 2018

초고속 엔진을 제어하는데 필요한 엔진으로 유입되는 공기유량의 추정기법에 대해 제안하였다. 비행 중 획득 가능한 정보를 활용하기 위하여 공기유량 계산식을 비행 중 측정 가능한 변수로 변경하였고, 추정 정확도에 대한 각각 변수의 기여도를 평가하였다. 제안한 추정식은 간단한 형태로 변형하였고, 측정 불확도를 분석하였다. 아울러 센서의 오차에 따른 민감도 분석을 통하여 공기유량 추정 기법 선택을 위한 참고자료를 제시하였다.

• 대한기계학회논문집B
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• 제38권7호
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• pp.625-638
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• 2014

본 연구에서는 천연가스 유량 측정에 사용되는 임계유동함수(CFF)를 AGA8-dc 상태방정식으로 계산할 때 CFF 계산값의 불확도를 평가하였다. CFF 계산에 사용되는 엔탈피, 엔트로피, 음속 식은 불확도 분석이 가능하도록 무차원 헬름홀츠 자유에너지(Helmholtz free energy, HFE)와 이의 편도함수로 표현하였고, HFE의 불확도를 추정하였다. 압축인자의 불확도에 의해 유발되는 종속 변수의 불확도를 반영하기 위해 AGA8-dc 압축인자 식을 해당 불확도만큼 편차가 생기는 형태로 변형하였고, 각 불확도 요인별로 불확도 기여도 평가 모델을 만들었으며, 이를 CFF 계산 프로그램에 적용하였다. 그 결과 CFF의 불확도는 압력 10, 50, 100 bar 에서 각각 0.025, 0.055, 0.112 % 정도로 평가 되었고 압력에 비례하여 증가하는 것을 확인하였다. 또한 본 결과를 기존 CFF 국제비교시험결과(1999년)에 적용한 결과 각 기관별 CFF 값의 차이를 적절히 설명하는 것도 알 수 있었다.