• 한국대기환경학회지
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• 제28권1호
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• pp.52-58
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• 2012

In this study, the effect of standard phase difference in calibration of carbonyl compounds (CC) was evaluated by using their standards prepared in both gaseous and liquid phase. For this analysis, standards in both phases were prepared for 6 different CCs (formaldehyde (FA), acetaldehyde (AA), propionaldehyde (PA), butyraldehyde (BA), isovaleraldehyde (IA) and valeraldehyde (VA)) at similar concentration levels. Their gaseous standard was calibrated after derivatization with three types of DNPH cartridge, and their calibration results were compared against liquid-phase standards. Although there was a strong compatibility between 2 phases for CCs with lower molecular weights (e.g., formaldehyde and acetaldehyde), it was not the case for the heavier CCs. The results of our analysis indicate that the analytical bias of the heavier CCs can be significantly large (by more than a few tens of %). As a result, underestimation of hevier CCs can be significant, if their gaseous samples are quantified by liquid phase standard.

• 대기
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• 제28권3호
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• pp.247-261
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• 2018

The objective of this paper is to compare probabilistic temperature forecasts from different regional and global ensemble prediction systems over PyeongChang area. A statistical post-processing method is used to take into account combination and calibration of forecasts from different numerical prediction systems, laying greater weight on ensemble model that exhibits the best performance. Observations for temperature were obtained from the 30 stations in PyeongChang and three different ensemble forecasts derived from the European Centre for Medium-Range Weather Forecasts, Ensemble Prediction System for Global and Limited Area Ensemble Prediction System that were obtained between 1 May 2014 and 18 March 2017. Prior to applying to the post-processing methods, reliability analysis was conducted to identify the statistical consistency of ensemble forecasts and corresponding observations. Then, ensemble model output statistics and bias-corrected methods were applied to each raw ensemble model and then proposed weighted combination of ensembles. The results showed that the proposed methods provide improved performances than raw ensemble mean. In particular, multi-model forecast based on ensemble model output statistics was superior to the bias-corrected forecast in terms of deterministic prediction.

• 한국항공우주학회지
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• 제50권9호
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• pp.617-625
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• 2022

본 논문은 사격 차선 정렬을 위하여 움직일 수 있는 교정 대상을 이용해 각속도계와 가속도계의 편차를 보상하는 방법을 다룬다. 교정 대상에 대한 정보는 영상 센서를 통해 획득하며 이를 이용해 발사장치에 부착된 관성측정 장치의 오차를 보정한다. 시뮬레이션을 통해 제안한 알고리즘의 성능을 검증하였으며, 특히 관성 좌표계에서 교정 대상에 대한 위치 정보를 정확하게 획득함으로써 발사장치의 관성 센서 편차를 효과적으로 보상할 수 있음을 보인다.

• 항공우주기술
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• 제4권2호
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• pp.117-125
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• 2005

관성항법유도장치는 관성센서 출력에 대한 측정 정밀도를 향상시키기 위해 자이로 및 가속도계의 아날로그 출력을 주파수로 변환해주는 AF(Analog to Frequency) 변환기를 사용한다. AF 변환기 측정 신뢰성을 보장하기 위해서는 신중한 교정절차가 결정되어야 하며, 교정절차에 의한 교정시험은 주기적으로 수행되어야 한다. 본 논문에서는 양ㆍ음의 입력에 대해 각각 양ㆍ음 리셋전류를 갖는 synchronous charge balance type의 AF 변환기 교정방법에 대해 다루었다. AF 변환기 교정은 AF 변환기 환산계수 오차 교정 시험과 바이어스 교정시험으로 나누어 수행되었으며, 교정 시험용 프로그램에 의해 자동으로 수행되었다.

• 한국물환경학회지
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• 제31권3호
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• pp.241-252
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• 2015

Runoff behaviors by five bias correction methods were analyzed, which were Change Factor methods using past observed and estimated data by the estimation scenario with average annual calibration factor (CF_Y) or with average monthly calibration factor (CF_M), Quantile Mapping methods using past observed and estimated data considering cumulative distribution function for entire estimated data period (QM_E) or for dry and rainy season (QM_P), and Integrated method of CF_M+QM_E(CQ). The peak flow by CF_M and QM_P were twice as large as the measured peak flow, it was concluded that QM_P method has large uncertainty in monthly runoff estimation since the maximum precipitation by QM_P provided much difference to the other methods. The CQ method provided the precipitation amount, distribution, and frequency of the smallest differences to the observed data, compared to the other four methods. And the CQ method provided the rainfall-runoff behavior corresponding to the carbon dioxide emission scenario of SRES A1B. Climate change scenario with bias correction still contained uncertainty in accurate climate data generation. Therefore it is required to consider the trend of observed precipitation and the characteristics of bias correction methods so that the generated precipitation can be used properly in water resource management plan establishment.

• 전자공학회논문지
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• 제52권11호
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• pp.36-43
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• 2015

본 연구를 통해서 초점면 배열 이차원 마이크로볼로미터를 위한 픽셀 단위의 신호취득 회로를 연구하였다. 높은 응답도와 긴 적분시간을 갖는 픽셀 단위의 구조를 위해 이 단계 바이어스 전류 억제 방식을 갖는 전류 미러 입력회로를 제안하였다. 제안하는 회로는 $0.35-{\mu}m$ 2-poly 4-metal CMOS 공정을 이용하여 설계했고, 마이크로볼로미터의 배열 크기는 $320{\times}240$이며 픽셀 크기는 $50{\mu}m{\times}50{\mu}m$이다. 제안하는 이 단계 바이어스 전류 억제 방식은 넓은 보정 범위에서 충분히 작은 보정 오차를 보이며, 설계 파라미터를 조정하여 보정 범위와 보정 오차를 간단히 최적화할 수 있다. 제안하는 회로는 높은 응답도와 1 ms 이상의 긴 적분시간을 갖기 때문에 회로의 잡음등가온도차(NETD)를 26 mK까지 개선할 수 있고, 이는 기존회로의 잡음등가 온도차인 67 mK에 비해 매우 개선된 수치이다.

• 한국태양에너지학회 논문집
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• 제38권6호
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• pp.65-72
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• 2018

Since data-driven building technologies have been widely applied to building energy systems, the accuracy of building sensors has more impacts on the building performance and system performance analysis. Various building sensors, however, can have typical errors including a random error (noise) and a systematic error (bias). The systematic error is indicated by the difference between the mean of measurements and their true value. It may occur due to the sensor's physical condition, measured phenomena, working environments inside the systems. Unfortunately, a conventional calibration method has limitations in calibrating the systematic errors because of the difference between working environments and calibration conditions. In such situations, a novel sensor calibration method is needed to handle various sensor errors, especially for systematic errors, in building energy systems having various thermodynamic environments. This study proposes a building sensor calibration method named Virtual In-situ Calibration (VIC) and shows how it is applied into a real building system and how it solves the sensor errors.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.426-429
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• 2008

In this study, we propose the calibration algorithm for the solar channel (550 ${\sim}$ 900 nm) of MTSAT 1R which is the Japanese geostationary satellite launched on 26 Feb. 2005 and located at $140^{\circ}E$. We developed a method utilizing MODIS-derived BRDFs for the solar channel calibration over the bright desert area. Targets are selected based on the desert's brightness, spatial uniformity, temporal stability and spectral stability. The 6S model has been incorporated to account for directional effects of the surface using MODIS-derived BRDF parameters within the spectral interval in interest. Results based on the analysis for the period from November 2007 to June 2008 suggest that MTSAT-1R solar channel measurements have a low bias within 5%.

• 제어로봇시스템학회논문지
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• 제18권7호
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• pp.632-637
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• 2012

This paper introduces a simple and efficient calibration method for three-axis accelerometers and three-axis gyroscopes using three-axis motion rate table. Usually, the performance of low cost MEMS-based inertial sensors is affected by scale and bias errors significantly. The calibration of these errors is a bothersome problem, but the previous calibration methods cannot propose simple and efficient method to calibrate the errors of three-axis inertial sensors. This paper introduces a new simple and efficient method for the calibration of accelerometer and gyroscope. By using a three-axis motion rate table, this method can calibrate the accelerometer and gyroscope simultaneously and simply. Experimental results confirm the performance of the proposed method.

• 한국화재소방학회논문지
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• 제32권4호
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• pp.1-6
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• 2018

본 연구는 Schmidt-Boelter형 열유속계의 측정 불확실도를 정량화하기 위한 기초연구로서 제조사에서 제공되는 보정상수의 측정오차를 평가하였다. 보정실험은 미국립표준기술원(NIST) 화재연구부의 2000 W급 할로겐-텅스텐 램프를 열원으로 적용한 열유속계 보정장치를 이용하였으며 동일 열유속 조건들에 대해 보정대상 열유속계와 표준열유속계를 비교하여 보정상수를 얻었다. 3개 제조사의 열유속계에 대한 보정실험 결과를 제조사의 보정상수와 비교하였다. 열유속계의 출력신호의 섭동값은 $1{\cdot}$를 넘지 않았으며 보정실험결과와 제조사의 보정상수의 상대오차는 1.5% ~ 14.3%까지 차이를 보였다. 본 연구는 정확한 열유속을 측정하기 위해 지속적이고 주기적인 보정과정이 필요함을 보여준다.