• 한국광학회지
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• 제17권5호
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• pp.391-395
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• 2006

본 논문에서는 온도 제어가 가능한 blackbody를 이용하여 수동형 FTIR 분광계의 radiometric calibration을 수행하고 타당성을 살펴보았다. Radiometric calibration은 분광계로 입사되는 radiance의 온도 변화에 대한 광 검출기의 파장 별 응답특성과 기기 내부에서 발생되는 온도 및 반사율에 의해 발생되는 측정 오차를 보정하여 Planck radiance로 변환하는 기법이다. 시료에 대한 calibration 과정을 수행한 스펙트럼을 spectral library와 비교한 결과, 흡수 스펙트럼의 파장 별 선폭과 상대적인 intensity가 매우 유사하게 나타났으며 입사 광원의 온도차와 비례하여 spectral intensity가 일정하게 증가됨을 확인할 수 있었다.

• 대한화학회지
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• 제47권1호
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• pp.19-25
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• 2003

흡수 분광법에 의해 얻은 스펙트럼을 주성분분석(principal analysis, PCA) 으로 자료를 요약하여 주성분 회귀분서(principal component regression, PCR)과 부분 최소자승법(partial least squares, PLS)으로 음이온과 비이온 계면활성제(anionic and nonionic surfactant)를 동시에 정량하는 방법에 대하여 연구하였다. 두 가지 계면활성제가 서로 다른 농도로 혼합되어 있는 26개의 시료용액을 400~700 nm 범위에서 스펙트럼을 얻었고, 이를 이용하여 PCR과 PLS회귀모델을 얻었다. 두 가지 계면활성제가 서로 다른 농도로 포함된 5개의 외부검정용 시료들의 스펙트럼들을 이용해서 회귀모델의 적합성을 검정하기 위하여 외부검정용 시료의 농도를 계산하였다. 계산된 농도를 이용하여 relative standard error of prediction(RSEP$_{\alpha}$)를 구하여 회귀모델의 적합성을 검정하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.891-896
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• 2007

This paper contained the flight test calibration for the airspeed indicator and the altimeter of the light airplane ChangGong-91, which is the first type certified aircraft from Korean Ministry of Construction and Transportation, as a part of the flight test validation. The flight test for airspeed position error calibration was performed using tower fly by method in order to calibrate swivel head testboom which is attached to the right wing tip of the airplane, and using system to system method for airspeed indicator. The altimeter calibration was calculated using flight test data for airspeed calibration. The flight test was conducted at the basis of the 'Korean Airworthiness Standard' regulation of Korean Ministry of Construction and Transportation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.656-659
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• 2004

As the demand for traceable calibrations of torque measuring devices has considerably increased both in the production sector and in research institutes, suitable standard machines had to be developed at the Korea Research Institute of Standards and Science. Owing to its special design, the small uncertainty of measurement required for the realization of the static torque can be reached (relative uncertainty of measurement ＆lt; 5$\times$10$^{-5}$ in the measurement range between 500 and 2000 Nm, and ＆lt; 1$\times$10$^{-4}$ in the measurement range from 10 to 500 Nm). The relative discrepancy between our torque calibration results of 2 kNm and PTB s (Physikalisch Technische Bundesanstalt, Germany) results was less than 2$\times$10$^{-5}$ , which confirming our uncertainty estimation.

• 전기학회논문지
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• 제56권7호
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• pp.1268-1274
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• 2007

A recently developed methods for the on-site calibration of the voltage transformer (VT) comparator system have been reviewed in the paper. The method utilizes the several traveling standards consisting of the VT, the non-reactive standard resistors, the wide ratio error VT, and the decade resistors. The VT is used for the absolute evaluation of a standard VT belonging to the industry. The non-reactive standard resistor and wide ratio error VT are used for the linearity check of errors in the voltage comparator of the industry. The decade resistors are used for evaluation of a VT burden of the industry.

• 약학회지
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• 제47권5호
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• pp.261-265
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• 2003

Near-infrared (NIR) system was used to determine rapidly and simply indomethacin in buffer solution for a dissolution test of tablets and capsules. Indomethacin standards were prepared ranging from 10 to 50 ppm using the mixture of phosphate buffer (pH 7.2) and water (1 : 4). The near-infrared (NIR) transmittance spectra of indomethacin standard solutions were collected by using a quartz cell in 1 mm and 2 mm pathlength. Partial least square regression (PLSR) was explored to develop calibration models over the spectral range 1100∼1700 nm. The model using 1 mm quartz cell was better than that using 2 mm quartz cell. The PLSR models developed gave standard error of prediction (SEP) of 0.858 ppm. In order to validate the developed calibration model, routine analysis was performed using another standard solutions. The NIR routine analysis showed good correlation with actual values. Standard error of prediction (SEP) is 1.414 ppm for 7 indomethacin samples in routine analysis and its error was permeable in the regulation of Korean Pharmacopoeia (VII). These results show the potential use of the real time monitoring for indomethacin during a dissolution test.

• 분석과학
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• 제19권6호
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• pp.553-558
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• 2006

본 연구에서는 Tedlar bag을 사용하여 조제한 작업용 기체상 표준시료를 열탈착과 GC/FID를 조합한 시스템으로 분석할 때, 발생 가능한 오차를 평가하고자 하였다. 이를 위해, 여러 가지 VOC성분(Benzene, Toluene, p-Xylene, Styrene)을 함유하는 표준시료를 4 가지 초기농도대(4~40 ppb)에서 조제하였다. 그리고 이들 작업용 시료를 이용하여, 각각의 검량결과를 도출하고 비교분석을 실시 하였다. 본 실험에서 설정한 4~40 ppb 농도대의 검량결과를 비교하기 위해, 공기분배/저온농축/열탈착 전용기(Air server/thermal desorber (AS/TD))와 조합한 GC/FID 시스템을 사용하였다. 본 연구의 결과, 표준시료의 조제방식이나 그와 연관된 초기농도의 차이가 검량 특성에 영향을 미친다고 하기는 어렵다는 결론을 내릴 수 있었다. 그러나 테들러백을 사용하는 경우, 여타 성분들에 비해 Styrene성분에서 감도가 떨어지는 경향이 크게 나타나는 점을 확인할 수 있었다.

• 한국정보통신학회논문지
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• 제20권9호
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• pp.1808-1815
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• 2016

댐 및 하천의 안정적인 운영은 국민의 생명 및 재산과 직결되는 상황으로 수문관측 데이터 신뢰성 확보는 안전재난 대비에 필수 요소이며, 과학적이고 신뢰성 있는 수자원 관리를 위하여 수위 데이터에 대한 실시간 자료 확보와 신뢰성 있는 데이터가 필요하나, 현재 운영되고 있는 댐이나 하천 상하류의 수위계는 신뢰성 확보를 위하여 현장에서 검교정이나 보정 등이 쉽지 않은 실정이다. K-water연구원에서는 유량계, 우량계, 수위계에 대한 국제공인 교정기관으로 운영중에 있으며, 우량계는 표준교정실 및 현장교정시스템을 이용하여 표준실 및 현장교정을 하고 있으나, 수위계는 표준교정실에서 실내 교정만 수행하고, 현장교정은 현장교정 절차서 및 시스템의 부재로 현장 교정을 하지 못하는 실정이다. 따라서, 수위계를 현장에서 교정할 수 있는 표준교정절차서 및 시스템을 개발하여, 수문관측 데이터의 신뢰성을 향상시키고자 한다.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1242-1242
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• 2001

The use of fibre optic probes for NIR quality control in the industry is becoming very important, as it provides a powerful tool to reduce sample analysis time and it facilitates the implementation of on-line analyses. However, most of the applications of fibre optics and probes have been done on suspensions, clear liquids and films, chemical and pharmaceutical products and also on fruits and animal products. Traditional applications of near infrared spectroscopy in agriculture have been developed in reflectance mode and calibration transfer could be an interesting way to reduce efforts. Classical methods for calibration transfer between different instruments involve the use of sealed reference cups, but, as fibre optic analysis does not use cups, it is necessary to develop new methods for calibration transfer without standards (Blank et al., 1996). In this paper, we have studied how the most used mathematical pretreatments (three methods of Multiplicative Scatter Correction, Standard Normal Variate, Detrending and derivatives) and their combinations applied to calibration development can contribute to reduce spectral differences between instruments. Calibration equations were obtained for three sets of cereals (barley, wheat and maize) scanned in reflectance mode and then they were validated with samples analysed in reflectance and interactance-reflectance mode (fibre optic). Preliminary results show how some combination of pretreatments reduce the differences in the predicted values, measured as standard error of differences, facilitating the use of calibrations obtained in reflectance for samples analysed by interactance-reflectance. However, the application of pretreatments is not enough to satisfy the control limits for calibration transfer suggested by Shenk et al. (1992), and it should be necessary to combine them with a specific algorithm for instruments standardization.

• Animal Bioscience
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• 제37권7호
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• pp.1196-1203
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• 2024

Objective: A study was conducted to quantify the performance differences of the near-infrared spectroscopy (NIRS) calibration models developed with different degrees of hay sample preparations. Methods: A total of 227 imported alfalfa (Medicago sativa L.) and another 360 imported timothy (Phleum pratense L.) hay samples were used to develop calibration models for nutrient value parameters such as moisture, neutral detergent fiber, acid detergent fiber, crude protein, and in vitro dry matter digestibility. Spectral data of hay samples prepared by milling into 1-mm particle size or unground were separately regressed against the wet chemistry results of the abovementioned parameters. Results: The performance of the developed NIRS calibration models was evaluated based on R², standard error, and ratio percentage deviation (RPD). The models developed with ground hay were more robust and accurate than those with unground hay based on calibration model performance indexes such as R² (coefficient of determination), standard error, and RPD. Although the R² of calibration models was mainly greater than 0.90 across the feed value indexes, the R² of cross-validations was much lower. The R² of cross-validation varies depending on feed value indexes, which ranged from 0.61 to 0.81 in alfalfa, and from 0.62 to 0.95 in timothy. Estimation of feed values in imported hay can be achievable by the calibrated NIRS. However, the NIRS calibration models must be improved by including a broader range of imported hay samples in the modeling. Conclusion: Although the analysis accuracy of NIRS was substantially higher when calibration models were developed with ground samples, less sample preparation will be more advantageous for achieving rapid delivery of hay sample analysis results. Therefore, further research warrants investigating the level of sample preparations compromising analysis accuracy by NIRS.