• Title/Summary/Keyword: Calibration Interval

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Development and Application of Calibration Interval Analysis Program for Measurement Quality and Reliability Improvement (측정 품질과 신뢰도 향상을 위한 교정주기 분석 프로그램의 개발 및 응용)

  • Park, Byoung-Sun;Ahn, Ung-Hwan;Cho, Joong-Jae
    • Journal of Korean Society for Quality Management
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    • v.34 no.1
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    • pp.54-72
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    • 2006
  • In recent years, the widespread application of quality management and measurement reliability has put increasing emphasis on procedures for periodic instrument calibration. By optimizing calibration intervals, unnecessary calibrations can be minimized, thereby reducing costs. Moreover, optimizing intervals will improve compliance with regulatory directives while ensuring maximal compliance with reliability targets. In this paper, we present Calibration Interval Analysis Program developed using several establishment methodologies of calibration interval for measurement quality and reliability improvement. Also, we perform calibration interval analysis for some measurement instruments and analyse its results.

Automatic Calibration for Noncontinuous Observed Data using HSPF-PEST (HSPF-PEST를 이용한 불연속 실측치 자동보정)

  • Jeon, Ji-Hong;Lee, Sae-Bom
    • Journal of The Korean Society of Agricultural Engineers
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    • v.54 no.6
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    • pp.111-119
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    • 2012
  • Applicability of 8 day interval flow data for the calibration of hydrologic model was evaluated using Hydrological Simulation Program-Fortran (HSPF) at Kyungan watershed. The 8 day interval flow monitored by Ministry of Environment located at upstream was calibrated and periodically validated during 2004-2008. And continuous daily flow monitored by Ministry of Construction & Transportation (MOCT) and located at the mouth was compared with daily simulated data during 2004-2007 as spatial validation. Automatic calibration tool which is Model-Independent Parameter Estimation & Uncertainty Analysis (PEST) was applied for HSPF calibration procedure. The model efficiencies for calibration and periodic validation were 0.63 and 0.88, and model performances were fair and very good, respectively, based on criteria of calibration tolerances. Continuous daily stream flow at the mouth of Kyungan watershed were good agreement with observed continuous daily stream flow with showing 0.63 NS value. The PEST program is very useful tool for HSPF hydrologic calibration using non-continuous daily stream flow as well as continuous daily stream flow. The 8 day interval flow data monitored by MOE could be used to calibrate hydrologic model if the continuous daily stream flow is unavailable.

Enhancement and Application of SWAT Auto-Calibration using Korean Ministry of Environment 8-Day Interval Flow/Water Quality data (환경부 8일 유량.수질 자료를 이용한 SWAT 자동보정 모듈 개선 및 적용 평가)

  • Kang, Hyunwoo;Ryu, Jichul;Kang, Hyungsik;Choi, Jaewan;Moon, Jongpil;Choi, Joongdae;Lim, Kyoung Jae
    • Journal of Korean Society on Water Environment
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    • v.28 no.2
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    • pp.247-254
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    • 2012
  • Soil and Water Assessment Tool (SWAT) model has been widely used in estimation of flow and water quality at various watersheds worldwide, and it has an auto-calibration tool that could calibrate the flow and water quality data automatically from thousands of simulations. However, only continuous measured day flow/water quality data could be used in the current SWAT auto-calibration tool. Therefore, 8-day interval flow and water quality data measured nationwide by Korean Ministry of Environment (MOE) could not be used in SWAT auto-calibration even though long-term flow and water quality data in the Korean Total Maximum Daily Load (TMDL) watersheds available. In this study, current SWAT auto-calibration was modified to calibrate flow and water quality using 8-day interval flow and water quality data. As a result of this study, the Nash and Sutcliffe Efficiency (NSE) values for flow estimation using auto-calibration are 0.77 (calibration period) and 0.68 (validation period), and NSE value for water quality (T-P load) estimation (using the 8-day interval water quality data) is 0.80. The enhanced SWAT auto-calibration could be used in the estimation of continuous flow and water quality data at the outlet of TMDL watersheds and ungaged point of watersheds. In the next study, the enhanced SWAT auto-calibration will be integrated with Web based Load Duration Curve (LDC) system, and it could be suggested as methods of appraisal of TMDL in South Korea.

Nonparametric kernel calibration and interval estimation (비모수적 커널교정과 구간추정)

  • 이재창;전명식;김대학
    • The Korean Journal of Applied Statistics
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    • v.6 no.2
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    • pp.227-235
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    • 1993
  • Calibration relates the estimation of independent variable which rquires more effort or expense than dependent variable does. It would be provided with high accuracy because a little change of the result of independent variable cn cause a serious effect to the human being. Usual statistical analysis assumes the normality of error distribution or linearity of data. It is desirable to analyze the data without those assumptions for the accuracy of the calibration. In this paper, we calibrated the data nonparametrically without those assumptions and derived confidence interval estimate for the independent variable. As a method, we used kernel method which is popular in modern statistical branch. We derived bootstrap confidence interval estimate from the bootstrap confidence band.

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Multivariate Linear Calibration with Univariate Controlled Variable

  • Park, Nae-Hyun
    • Journal of the Korean Statistical Society
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    • v.15 no.2
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    • pp.107-117
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    • 1986
  • This paper gives some new results on the multivariate linear calibration problem in the case when the controlled variable is univariate. Firstly, a condition under which one can obtain a finite closed confidence interval of $x_0$(unknown controlled variable) is suggested. Secondly, this article considers a criterion to find out whether the multivariate calibration significantly shortens the confidence interval of $x_0$ and supports this criterion by examples. Finally, a multivariate extension of the results in Lwin Maritz (1982) is given.

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Evaluation of the Possibility of Daily Flow Data Generation from 8-Day Interval Measured Flow Data using SWAT-CUP (SWAT-CUP을 이용한 8일간격 유량측정자료의 일유량 확장 가능성 평가)

  • Jung, Jaewoon;Cho, Sohyun;Lim, Byungjin;Oh, Taeyoun;Ham, Sangin;Kim, Kapsoon
    • Journal of Korean Society on Water Environment
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    • v.28 no.4
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    • pp.595-600
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    • 2012
  • This study is to assess the application of SWAT-CUP(Soil and Water Assessment Tool-Calibration Uncertainty Programs) and to extend daily flow data from 8-day interval flow data which has been measured by Korean Ministry of Environment(MOE). Model sensitivity analysis and calibration were performed with sequential uncertainty fitting(SUIF-2), which is one of the programs interfaced with SWAT, in the package SWAT-CUP. The most sensitive parameters were SOL_K.sol, CH_N2.rte, CN2.mgt, SOL_BD.sol, ALPHA_BF.gw, ALPHA_BNK.rte, SOL_AWC.sol, CH_K2.rte, SFTMP.bsn, GW_DELAY.gw. Following the sensitivity analysis, SWAT-CUP calibration was carried out using 8-day interval flow data from January 2008 to December 2010. The results were then assessed based on the visual agreement and simulated flow plots and the performance statistics generated $R^2$ and NSE which are 0.71 and 0.61 respectively. Results of these statistics indicated that there was a good agreement between the observed and simulated flow. To extend daily flow data from 8-day interval flow data, parameters, which were estimated by SWAT-CUP, re-entered for SWAT model. As a result, the observed flow data were found to reflect the trend of simulated flow data. From these results, it is thought that this method could be used to provide daily flow data using 8-day interval flow data.

Video Image Detector Calibration Period Decision (영상검지기 교정주기 설정방안)

  • Lee, Chung-Won;Baik, Nam-Cheol;Song, Young-Hwa;Jang, Jin-Hwn
    • Journal of Korean Society of Transportation
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    • v.23 no.5 s.83
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    • pp.177-185
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    • 2005
  • The accuracy of a video image detector(VID) is gradually reduced due to the various environmental and mechanical factors. But there has been no systematic research about this VID accuracy decreasing. To maintain a proper level of VID accuracy for the advanced traffic management. a regular VID calibration process needs to be introduced. Because of its cost, however. the calibration cannot be performed frequently. Therefore, the method to decide the optimal calibration interval should be studied in details. This study presents two different calibration interval decision methods. Using the invented data collection equipment. some data in the field were collected and analyzed. which were used for the adaptability checking. Although the data were limited. the result is pretty promising. More data needs to be investigated later and this study will help to maintain the data quality of the ITS center.

Calibration Interval Analysis Method Based on F-test and Performance Index of Measurement Reliability Model Using Maintenance Data in Military Weapon Systems (군 무기체계에서 정비 데이터를 이용한 측정신뢰도 모델의 F-검정 및 성능지수 기반 교정주기 분석 기법)

  • Cha, Yun-bae;Kim, Boo-il
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.11
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    • pp.2191-2198
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    • 2017
  • The PME(precision measurement equipment) used in the measurement to check the performance of the equipment in military weapon system is periodically calibrated to maintain measurement reliability during the life cycle. Previous studies suggest that reliability models are determined by considering sample size and characteristics of equipment. However, it may not be fit well to apply a single model assuming the same characteristic distribution for the maintenance date of many kinds of PMEs. This paper proposes that the most suitable calibration interval for maintenance data is selected through the F-test and the performance index evaluation among the calibration intervals estimated from the measurement reliability models assuming the characteristic of the bath-tub curve during the life cycle of various PMEs. The research results show that the reliabilities of various types of equipment are maintained during calibration intervals.

Optimal Calibration Interval Analysis Method through the Goodness of Fit Test of Measurement Reliability Models based on Maintenance Data (정비 데이터 기반 측정신뢰성 모델 적합성 검정에 의한 최적 교정주기 분석 기법)

  • Cha, Yun-bae;Kim, Boo-il
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.05a
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    • pp.178-180
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    • 2016
  • TMDE(Test Measurement and Diagnostic Equipment) which is using in the military weapon system should perform the periodic calibration to maintain a measurement reliability during the life cycle, organizations are faced with increasing pressures to minimize costs while improving the reliability of test equipment. Previous studies suggest that reliability models are determined by considering simple size and characteristics of equipment, however an applying single Model may not be fit well maintenance data of many kinds of TMDEs. This paper presents that recommending an optimal calibration interval through the goodness of fit test with verifying statistical significance level among the several intervals which are computed with using major reliability models. According to the result of applying the actual proposed of calibration interval analysis method for various types of equipment, reliabilities are maintained for the end of calibration intervals.

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The Effect of Reynolds Number on the Calibration of a Five-Hole Probe at Low Reynolds Numbers (저 Reynolds 수 영역에서 Reynolds 수가 5공 프로우브의 보정에 미치는 영향)

  • Lee, Sang Woo;Jun, Sang Dae
    • 유체기계공업학회:학술대회논문집
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    • 2000.12a
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    • pp.193-199
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    • 2000
  • The effects of Reynolds number on the non-nulling calibration of a cone-type five-hole probe in low-speed flows have been investigated at the Reynolds numbers of $2.04{\times}10^3,\;4.09{\times}10^3$, and $6.13{\times}10^3$. The calibration is conducted at the pitch and yaw angles in ranges between -35 degrees and 35 degrees with an angle interval of 5 degrees. The result shows that each calibration coefficient, in general, is a function of the pitch and yaw angles, so that the pre-existing calibration data in a nulling mode are not enough in accounting for the full non-nulling calibration characteristics. Due to the interference of the probe stem, the calibration coefficients have more Reynolds number sensitivity at positive pitch angles than at negative ones.

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