• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.1068-1072
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• 1991

This paper presents a decentralized model reference adaptive control scheme for an interconnected continuous linear system composed of a number of single-input single-output subsystems in which outgoing interactions pass through the measurement channel and are subject to bounded external disturbance. The scheme can treat the unknown strength of interactions as well as the uncertainty of subsystems.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.285-286
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• 2003

대기중의 황화물은 대표적인 악취물질로서 악취오염원 관리시에 이에 대한 측정이 자주 이루어 지고있다. 황화물의 경우 nmole/mole(ppb) 또는 그 이하의 농도의 극미량에서도 사람이 악취를 느끼게 하고있어 이를 관리하기 위해서는 이렇게 매우 낮은 농도까지 측정이 이루어져야 한다. 황화물은 반응성이 크고, 흡착성이 커서 일반 휘발성 유기물과는 달리 낮은 농도에서 더욱 안정성이 떨어지므로 정확한 측정이 매우 어렵다. 본 연구에서는 이러한 황화물의 측정 정확도를 확립하기 위해서 측정 단계별 불확도 평가를 수행하였다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.384-385
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• 2003

일상 생활에서 악취로 인한 피해를 줄여 쾌적한 생활환경 유지에 대한 관심이 높아짐에 따라 이에 관련된 탈취제품이 많이 상품화되고 있다. 본 연구에서는 탈취 성능에 대하여 객관적으로 평가할 수 있는 시험 분석법을 개발하고, 탈취 성능 평가방법의 정확도를 확립하기 위해 단계별 불확도 평가를 수행하였다. 측정 불확도 요인을 체계적으로 평가하여 주요 불확도 요인을 파악하고 이를 최소화하기 위하여 어떠한 점을 주의하여야 하는 지를 조사하였다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.04a
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• pp.141-142
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• 2002

대기환경 기준물질(criteria pollutants)은 NOx를 비롯하여 $O_3$, CO, SOx, PM 10, Pb 인데, 이러한 물질은 환경부에서 법적으로 규정한 대기오염공정 시험법에 따라서 분석된다. 대기오염공정 시험법이 충분한 과학적 근거를 갖는 분석법이 되기 위해서는 분석방법, 분석기기, 분석자 등에 의해 발생되는 불확실성을 최소화시키는 체계적인 관리가 필요하고, 분석기술의 발달수준, 측정분석의 요구수준, 새로운 국제 규격 통에 맞게 지속적으로 보완되어야 한다. (중략)

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.129-134
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• 1998

In this paper, a simple method is presented to synthesize a transfer function from experimentally obtained gain and phase data. The method we offer here is based on the previous method given by M.Hassul etc. [1], where they proposed relevant formulas in a straightforward manner so that undergraduate students could follow the development more easily. This method, however, inevitably is accompanied by a significant difference between the real and identified model especially in the low frequency region. We solve this problem by introducing a new weighting function that can be determined by using the additive uncertainty of the Identified transfer function.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.39-42
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• 2003

중금속으로 오염된 폐광산 주변부나 유류누출로 인한 토양오염 등과 같은 오염부지에 대한 환경조사는 그 결과를 토대로 환경계획이나 정책이 수립되므로 의사결정의 기초가 된다. 이때, 의사결정의 타당성은 오염부지 조사결과 오염도가 얼마나 정확하게 측정되었느냐에 따라 달리 평가되어 진다. 그러므로 이와 같은 환경조사는 측정결과의 불확실성이 감소되도록 정밀한 시료채취방법이나 분석방법을 고안하여 적용해야 한다. (중략)

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.104-108
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• 1993

The linear length measurements are most frequently performed and should be most accurate among other parts in dimensional metrology. We developed the linear measuring system using a laser interferometer to improve the accuracy and to shorten the calibration time. The uncertainty of the system is 0.01 .mu. for 500mm steel gage block. The range of the measurement and resolution of the system are 1000mm and 0.01 .mu. m, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.17-17
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• 2010

This paper address technical issues in calibrating discharge coefficients of sonic nozzles used to measure the volume flow rate of low vacuum dry pumps. The first challenging issue comes from the technical limit that their calibration results available from the flow measurement standard laboratories do not fully cover the low vacuum measurement range although the use of sonic nozzles for precision measurement of gas flow has been well established in NMIs. The second is to make an ultra low flow sonic nozzlesufficient to measure the throughput range of 0.01 mbar-l/s. Those small-sized sonic nozzles do not only achieve the noble stability and repeatability of gas flow but also minimize effects of the fluctuation of down stream pressures for the measurement of the volume flow rate of vacuum pumps. These distinctive properties of sonic nozzles are exploited to measure the pumping speed of low vacuum dry pumps widely used in the vacuum-related academic and industrial sectors. Sonic nozzles have been standard devices for measurement of steady state gas flow, as recommended in ISO 9300. This paper introduces two small-sized sonic nozzles of diameter 0.03 mm and 0.2 mm precisely machined according to ISO 9300. The constant volume flow meter (CVFM) readily set up in the Vacuum center of KRISS was used to calibrate the discharge coefficients of the machined nozzles. The calibration results were shown to determine them within the 3% measurement uncertainty. Calibrated sonic nozzles were found to be applicable for precision measurement of steady state gas flow in the vacuum process. Both calibrated sonic nozzles are demonstrated to provide the precision measurement of the volume flow rate of the dry vacuum pump within one percent difference in reference to CVFM. Calibrated sonic nozzles are applied to a new 'in-situ and in-field' equipment designed to measure the volume flow rate of low vacuum dry pumps in the semiconductor and flat display processes.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.255-260
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• 2006

Safety-critical navigation systems have to provide 'reliable' position solutions, i.e., they must detect and exclude measurement or system faults and estimate the uncertainty of the solution. To obtain more accurate and reliable navigation systems, various filtering methods have been employed to reduce measurement noise level, or integrate sensors, such as global navigation satellite system/inertial navigation system (GNSS/INS) integration. Recently, particle filters have attracted attention, because they can deal with nonlinear/non-Gaussian systems. In most GNSS applications, the GNSS measurement noise is assumed to follow a Gaussian distribution, but this is not true. Therefore, we have proposed a fault detection and exclusion method using particle filters assuming non-Gaussian measurement noise. The performance of our method was contrasted with that of conventional Kalman filter methods with an assumed Gaussian noise. Since the Kalman filters presume that measurement noise follows a Gaussian distribution, they used an overbounded standard deviation to represent the measurement noise distribution, and since the overbound standard deviations were too conservative compared to the actual distributions, this degraded the integrity-monitoring performance of the filters. A simulation was performed to show the improvement in performance of our proposed particle filter method by not using the sigma overbounding. The results show that our method could detect smaller measurement biases and reduced the protection level by 30% versus the Kalman filter method based on an overbound sigma, which motivates us to use an actual noise model instead of the overbounding or improve the overbounding methods.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3178-3182
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• 2007

The interferometer method with nano-scale spatial resolution has been developed in this study. To enhance the accuracy of the previous developed method, the 14 bit cooled CCD camera with 1280 by 980 spatial resolution was applied to the measurement. And optical alignment has been carried out on the highly accurate position sensors with 500nm resolution so as to be able to calibrate the detected interference image with the field of view. Also the measurements were applied to the ultra thin oil film between the Al coated cylinder mirror with 38.1mm radius and 0.5mm cover glass to verify the developed method. The measured result showed the good agreement with the used cylinder curvature with ${\pm}$5.18run uncertainty.