• 제어로봇시스템학회논문지
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• 제5권2호
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• pp.200-207
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• 1999

In this paper, a precise sensitivity measurement system of ultrasonic transducer in the frequency range from 1 MHz to 15 MHz, which can implement the reciprocity principle is constructed. All of the elements of this system such as the ultrasonic preamplifier, ultrasonic absorber, water tank, water degassing system, and four-axes translator and reflector are constructed. For the performance evaluation of the calibration system, a standard hydrophone precisely calibrated from PTB(Physikalisch Technische Bundesanstalt) in Germany are used. And the system parameters which affected the evaluation of the measurement accuracy and the reproducibility in various measuring conditions are considered. The measurement uncertainty of the calibration system is estimated within $\pm$ 2.0㏈.

• 한국방사선학회논문지
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• 제1권2호
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• pp.31-35
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• 2007

Energy calibration is important to identify accurate neutron capture resonance energy in the neutron TOF (Time-of-Flight) experiment. In present study, the accurate neutron capture resonance energies of natural Sm were measured by using a 46-MeV electron linear accelerator (linac) at the Research Reactor Institute, Kyoto University(KURRI). The BGO spectrometer were adopted for measurement the prompt capture gamma-ray of the sample. To obtain energy calibration curve, resonance energy of a gold sample used as standard resonance energy Mughabghab's data (From neutron resonance parameters data). Previous data (by Mughabghab) of natural Sm sample have been compared with the present result.

• 소음진동
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• 제8권5호
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• pp.879-886
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• 1998

An automated calibration system of sound level meters was developed and tested. As a standard sound source, the speaker unit(Forstex FE208) cabineted by 440$\times$390$\times$490 $\textrm{mm}^3$(LHW) volume wood box was adopted. Including this source, the driving part was found out to have a good linearity of sound pressure output vs AC voltage input. The Hybrid-Bisect/Newton-Raphson method modified by the linearity was adopted as a searching algorithm. Uisng GPIB interface, the console PC make the control, measurements, and calculations and finally make the accumulation of useful data and results automatically by the instructon in the program coded by C languate. Several trials of automatic calibration using this developed system give the reliable results.

• Journal of Radiation Protection and Research
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• 제41권3호
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• pp.211-215
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• 2016

Background: The moderated neutron calibration fields using $^{241}Am$-Be sources and a graphite moderator have been constructed at the Facility of Radiation Standard (FRS) in the Japan Atomic Energy Agency (JAEA). Materials and Methods: The neutron spectra of the fields were evaluated by the Monte-Carlo calculations and measurements using the Bonner Multi-sphere Spectrometer. Results and Discussion: The fields have continuous neutron spectra from several MeV to thermal neutron energy, with fluence-averaged energies of 0.84 MeV and 0.60 MeV. Reference values of fluence rates and ambient/personal dose equivalent rates were determined from neutron spectra by measurements. Conclusion: Currently, the fields are available for calibration or performance test of neutron measuring instruments.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1998년도 추계학술대회 학술발표 논문집
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• pp.187-190
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• 1998

The values of physical components of the plants and controllers as well as the relevant environmental conditions change in time, thus the output performance can be deteriorated during the operating span of the system. Naturally the duty of calibration or the prevention of performance deterioration due to excessive component sensitivity should be provided to the control system. The proposed controller, whenever necessary, measures the open-loop and close-loop characteristics, and then calculates the offset and sensor gain correction values based on the prepared standard measurements It is applied to the control of a flexible link system with the gain and offset calibration problems in the light sensor module for position to show the applicability. In this paper, we propose a digital controller which has the capability of calibration gain and offset adjustment using fuzzy methods.

• 한국가시화정보학회지
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• 제18권3호
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• pp.122-128
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• 2020

In the field of experimental fluid dynamics, the 5-hole probe is one of the most widely used tools to measure flow velocity and pressure. We hereby describe the development of an inexpensive laboratory-based flow calibration system for 5-hole probes. The system is applied to a custom L-shaped probe, and the probe performance is compared against a standard commercial probe in a custom wind tunnel. The setup allows rotation of the probe around the yaw and pitch axes. Static and total pressure values are calculated, and then calibration maps are constructed based on the yaw and pitch angles. Using these maps, errors of the custom probe are found to be ±5% for velocity magnitude and ±3° for direction, compared to the commercial probe, when both pitch and yaw angles are within 40°.

• 대기
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• 제25권1호
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• pp.19-30
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• 2015

The Ka-band cloud radar (KCR) has been operated by the National Institute of Meteorological Research (NIMR) of Korea Meteorological Administration (KMA) at Boseong National Center for Intensive Observation of severe weather since 2013. Evaluation of data quality is an essential process to further analyze cloud information. In this study, we estimate the measurement error and the sampling uncertainty to evaluate data quality. By using vertically pointing data, the statistical uncertainty is obtained by calculating the standard deviation of each radar parameter. The statistical uncertainties decrease as functions of sampling number. The statistical uncertainties of horizontal and vertical reflectivities are identical (0.28 dB). On the other hand, the statistical uncertainties of Doppler velocity (spectrum width) are 2.2 times (1.6 times) larger at the vertical channel. The reflectivity calibration of KCR is also performed using X-band vertically pointing radar (VertiX) and 2-dimensional video disdrometer (2DVD). Since the monitoring of calibration values is useful to evaluate radar condition, the variation of calibration is monitored for five rain events. The average of calibration bias is 10.77 dBZ and standard deviation is 3.69 dB. Finally, the statistical characteristics of cloud properties have been investigated during two months in autumn using calibrated reflectivity. The percentage of clouds is about 26% and 16% on September to October. However, further analyses are required to derive general characteristics of autumn cloud in Korea.

• Asian-Australasian Journal of Animal Sciences
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• 제17권12호
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• pp.1736-1740
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• 2004

Since the application of relatively high levels of heavy metals in the compost poses a potential hazard to plants and animals, the content of heavy metals in the compost with animal manure is important to know if it is as a fertilizer. Measurement of heavy metals content in the compost by chemical methods usually requires numerous reagents, skilled labor and expensive analytical equipment. The objective of this study, therefore, was to explore the application of near-infrared reflectance spectroscopy (NIRS), a nondestructive, cost-effective and rapid method, for the prediction of heavy metals contents in compost. One hundred and seventy two diverse compost samples were collected from forty-seven compost facilities located along the Han river in Korea, and were analyzed for Cr, As, Cd, Cu, Zn and Pb levels using inductively coupled plasma spectrometry. The samples were scanned using a Foss NIRSystem Model 6500 scanning monochromator from 400 to 2,500 nm at 2 nm intervals. The modified partial least squares (MPLS), the partial least squares (PLS) and the principal component regression (PCR) analysis were applied to develop the most reliable calibration model, between the NIR spectral data and the sample sets for calibration. The best fit calibration model for measurement of heavy metals content in compost, MPLS, was used to validate calibration equations with a similar sample set (n=30). Coefficient of simple correlation (r) and standard error of prediction (SEP) were Cr (0.82, 3.13 ppm), As (0.71, 3.74 ppm), Cd (0.76, 0.26 ppm), Cu (0.88, 26.47 ppm), Zn (0.84, 52.84 ppm) and Pb (0.60, 2.85 ppm), respectively. This study showed that NIRS is a feasible analytical method for prediction of heavy metals contents in compost.

• 센서학회지
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• 제4권1호
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• pp.43-50
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• 1995

고온에서 교정용 표준기로 사용되는 S형 열전대를 사용하여, 국내의 9개 고온분야 교정검사기관의 고온측정 능력을 순회교정을 통하여 평가하여 고온의 소급성 오차를 측정하였다. 참여기관 중 3개교정검사기관만이 열전대의 교정불확도인 ${\pm}0.5^{\circ}C$이내에서 한국표준과학연구원의 측정값과 일치하였으며, 나머지 6개 기관의 측정값은 규정된 불확도를 벗어났다. 각 측정값의 차이는 온도가 높아질수록 증가하여 비교측정점 중 가장 높은 온도인 금점에서 가장 큰 차이가 $2^{\circ}C$로 교정 불확도를 크게 벗어났다. 이 연구에서 측정된 국내 고온분야 교정검사기관의 소급성 오차는 $2.0^{\circ}C$ 이내였다.

• 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.