• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2492-2494
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• 2005

This study designed on the standard calibration facility for calibration about radar type, ultra-sonic type and floating type. We reviewed calibration facilities, analysis any problems, and proposed optimal plan which uses EDM and electrical level meter.

• Analytical Science and Technology
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• v.23 no.1
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• pp.24-35
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• 2010

To learn more about the calibration properties of reduced sulfur compounds (RSCs) by the combination of gas chromatography(GC)-pulsed flame photometric detector (PFPD) and thermal desorption method, a series of calibration experiments were conducted on the basis of both internal and external calibration approaches. For these experiments, gaseous standards of 4 RSCs ($H_2S$, $CH_3SH$, DMS, and DMDS) were prepared at two different concentration levels of both low (10, 20, 50,and 100 ppb) and high ranges (100, 200, 500, and 1000 ppb) along with $CS_2$ as an internal standard. First, the external calibration results were compared between fixed standard volume (FSV) and fixed standard concentration (FSC) method. Secondly, FSV-based calibration results were compared between external and internal calibration results. As FSV method suffers from sensitivity variations less significantly than FSC, the former is recommended to maintain the consistency in GC-TD sensitivity for RSC analysis. In addition, when the calibration data were examined in terms of RSE between external and internal calibration data, the results were not consistent enough to show improvements in internal method. Hence, diverse efforts are desirable to optimize the reproducibility in terms of GC-TD sensitivity for RSC analysis.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.2
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• pp.151-156
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• 2008

Many kinds of mass spectrometer type leak detectors have been widely used for detecting leak of vacuum processes in semiconductor and display industries etc. The leak detectors should be often calibrated by the permeation type standard leak in order to ensure accurate and reproducible leak measurement. We have developed a comparative calibration system for permeation type standard leak by using mass spectrometer type leak detector and specification of the calibration method. Following this technique the reliable calibration for leak standard ran be performed even in fields.

• Applied Chemistry for Engineering
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• v.31 no.3
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• pp.334-337
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• 2020

Korea Laboratory Accreditation Scheme (KOLAS) introduces a new standard for test and calibration laboratories to operate management system and to produce valid results in accordance with the requirements of KS Q ISO/IEC 17025. The standard is based on the national standard law for the accreditation of test, inspection and calibration laboratories. International Laboratory Accreditation Cooperation (ILAC) has recently established its new criteria. The accredited test and calibration laboratories should complete the transition of their management system by November 2020 following KS Q ISO/IEC 17025:2017. A total of 899 of test, inspection and calibration laboratories in Korea are influenced by the transition policy. This paper summarized general requirements for a competence of laboratory management system.

• Near Infrared Analysis
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• v.1 no.1
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• pp.1-7
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• 2000

A convenient algorithm for optimizing wavelength selection in multiple linear regression (MLR) has been developed. MOP (MLP Optimization Program) has been developed to test all possible MLR calibration models in a given spectral range and finally find an optimal MLR model with external validation capability. MOP generates all calibration models from all possible combinations of wavelength, and simultaneously calculates SEC (Standard Error of Calibration) and SEV (Standard Error of Validation) by predicting samples in a validation data set. Finally, with determined SEC and SEV, it calculates another parameter called SAD (Sum of SEC, SEV, and Absolute Difference between SEC and SEV: sum(SEC+SEV+Abs(SEC-SEV)). SAD is an useful parameter to find an optimal calibration model without over-fitting by simultaneously evaluating SEC, SEV, and difference of error between calibration and validation. The calibration model corresponding to the smallest SAD value is chosen as an optimum because the errors in both calibration and validation are minimal as well as similar in scale. To evaluate the capability of MOP, the determination of benzene content in unleaded gasoline has been examined. MOP successfully found the optimal calibration model and showed the better calibration and independent prediction performance compared to conventional MLR calibration.

• Journal of Sensor Science and Technology
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• v.14 no.4
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• pp.231-236
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• 2005

Calibration capability was evaluated using the reference-grade platinum resistance thermometer (PRT) in the temperature range of $-50^{\circ}C$ to $250^{\circ}C$ for the national calibration centers. The reference-grade PRT was calibrated at the several fixed points, which was composed by the freezing points of Sn, In, the melting point of Ga and the triple point of water and Hg, before and after the round-robin test (RRT) experiments. The temperature scale of reference-grade PRT was compared to the local standard PRT's using the system of the national calibration centers. $E_{n}$ values was calculated by the temperature difference between the reference-grade PRT and the local standard PRT, and the best measurement capability. Finally, the capability of the national calibration centers was evaluated by the $E_{n}$ values.

• Journal of Korean Institute of Industrial Engineers
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• v.19 no.2
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• pp.35-41
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• 1993

Statistical calibration is a useful technique for achieving compatibility between two different measurement methods, and it usually consists of two steps : (1) estimation of the relationship between the standard and nonstandard measurements, and (2) prediction of future standard measurements using the estimated relationship and observed nonstandard measurements. A predictive multivariate errors-in-variables model is presented for the multivariate calibration problem in which the standard as well as the nonstandard measurements are subject to error. For the estimation of the relationship between the two measurements, the maximum likelihood (ML) estimation method is considered. It is shown that the direct and the inverse predictors for the future unknown standard measurement are the same under ML estimation. Based upon large-sample approximations, the mean square error of the predictor is derived.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.911-917
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• 2018

Influence of the adaptors on the calibration of $100{\mu}H$ inductance standard was studied as a function of torque, applied when tightening the standard inductor terminal with the adaptor. Two different homemade adaptors of BPO gold-plated brass (BPO-Au) and banana-copper (BN-Cu) were made for the connection between the LCR meter and the inductance standard. The measured inductance (L) of the standard inductor and the contact resistance ($R_C$) between the adaptor and the standard inductor terminal showed exponential decreases against the torque increase from $25cN{\cdot}m$ to $150cN{\cdot}m$. The measured L and the calculated equivalence series resistance ($R_S$) were dependent on the adaptor type as well as on the $R_C$. The results of the adaptor analysis imply that the BPO-Au adaptor with the lower $R_C$ is more suitable for the inductance calibration. The calculated inductance of $99.956{\mu}H$ corrected by subtraction of the adaptor inductance and the contact resistance contributions from the measured value using the BPO-Au adaptor agreed well with the certificate ($99.948{\mu}H$) of the PTB within the measurement uncertainty of $140{\mu}H/H$.

• Journal of the Korean Statistical Society
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• v.17 no.1
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• pp.9-23
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• 1988

The classicla theory of statistical calibration assumes that the standard measurement is exact. From a realistic point of view, however, this assumption needs to be relaxed so that more meaningful calibration procedures may be developed. This paper presents a model which explicitly considers errors in both standard and nonstandard measurements. Under the assumption that replicated observations are available in the calibration experiment, three estimation techniques (ordinary least squares, grouping least squares, and maximum likelihood estimation) combined with two prediction methods (direct and inverse prediction) are compared in terms of the asymptotic mean square error of prediction.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1990.04a
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• pp.254-262
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• 1990

A predictive functional relationship model is presented for the calibration problem in which the standard as well as the nonstandard measurements are subject to error. For the estimation of the relationship between the two measurements, the ordinary least squares and maximum likelihood estimation methods are considered, while for the prediction of unknown standard measurementswe consider direct and inverse approaches. Relative performances of those calibration procedures are compared in terms of the asymptotic mean square error of prediction.