• The KSFM Journal of Fluid Machinery
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• v.13 no.6
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• pp.36-41
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• 2010

Design, manufacture and calibration procedures of a venturi pipe flowmeter for airflow measurement in altitude engine test were discussed. Altitude engine test using venturi pipe was given as an example. The venturi was designed per the ISO standard of ISO5167, and was intented to include the entire airflow range in the test envelope of the gas turbine engine. Measurement uncertainty analysis was performed in the design procedure to investigate the effect of venturi geometry and sensor specification upon the measurement uncertainty. Manufacturing process was designed to minimize the deviation from the geometry of design. Calibration was performed to get the relationship between the discharge coefficient and the pipe Reynolds number. Then the uncertainty was assessed again using real data acquired during engine test. Through these procedures, it was possible to maintain the uncertainty of airflow measurement under 1 % for most of the operating envelope of the gas turbine engine. The discharge coefficient of the venturi pipe showed agreement with the value suggested in the ISO standard ISO5167-4 within 0.6 %.

• The Journal of the Acoustical Society of Korea
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• v.42 no.2
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• pp.143-151
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• 2023

In this paper, a method for evaluating the measurement uncertainty is proposed when measuring of floor impact sound insulation of buildings using standard heavy impact source. In addition to the effect of repeated measurements, several other factors such as measurement location, impact location, equipment used for sound pressure measurement, and heavy impact source, were considered. A mathematical model for the average maximum impact sound level and the uncertainty evaluation method for each factor were proposed. The present proposed method was applied to measurement results to evaluate the average maximum impact sound pressure level and the measurement uncertainty.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.669-672
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• 2002

Establishment of the Quantum Hall Resistance(QHR) Standard as national resistance standard using a room temperature DCC resistance bridge is described. A simple method are used to obtain the current dependence and error of 10: 1 ratio of the bridge instead of the method using a cryogenic resistance bridge. Measurement uncertainty of the system is estimated as $0.14{\times}10^{-6}$ and it is confirmed that the QHR standard is agreed well with the QHR of other NMIs using the cryogenic resistance bridge within the uncertainty, More improvement about performance of the QHR device and 10: 1 ratio accuracy is still under progress.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.10 s.241
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• pp.1130-1138
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• 2005

A national standard system for the petroleum field has been developed to calibrate and test the oil flow meters in Korea. The operating system and the uncertainty of the system were evaluated by the peer reviewers of foreign national metrology institutes in 2002. Since the characteristics of the system might be changed by time, the uncertainty of the system is reevaluated with the consideration of the long term stability of the system. It is found that the system has a relative expanded uncertainty of 0.048 $\%$ in the range of $15\~120\;m^3/h$. According to the uncertainty budget, the uncertainties of the fluid density and the final mass measurement, which are temperature dependent, contribute about $94\%$ of the total uncertainty in the oil flow standard system

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1384-1387
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• 1996

SCPI(Standard Commands for Programmable Instrument) is a standard command sets designed for controlling various types of instruments. In order to control FFT(Fast Fourier Transform) analyzing device using SCPI it is required to support sweep measurement function. We defined SCPI command set for FFT analysis and developed parser of defined command set using lex(Lexical Analyzer Generator) and yacc(Yet Another Compiler Compiler). After developing FFT analyzing test was performed with that parser. Up to audible signal frequency the result of FFT analysis was accurate and that result was agree with that of conventional FFT analyzer. As a result it is proved that various types of instruments including sweep measurement instrument can be controlled with appropriate SCPI command sets. Also when developing new instruments the method used in this experiment will contribute to reducing the time required to develop the SCPI parser and increasing reliability.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2468-2473
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• 2005

Because the rain gauges of tipping bucket type can easily use the digital signal, the rain gauges are widely used for the meteorological observation. In general, the resolution of rain gauges of tipping bucket type can be categorized by the 0.1mm, 0.5mm, and 1.0mm classes. But, the error of the tipping bucket rain gauges is made by the intensity of rainfalls and is expected to make the standard calibration method for error measurement. Thus, we developed the hardware of standard calibration facility for rain gauges by weighting measurement method and proposed the standard procedure by rainfall intensity in this study Also, we calculated the error for the rainfall intensity and obtained useful result through the proposed calibration method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.6
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• pp.886-892
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• 2000

In this paper, surface transfer impedance measurement of RF cables according to IEC(International Electrotechnical Commission) Standard 96-1 is described and surface transfer impedance of a commercial RF cable is obtained from the measured voltage and scattering parameter with a triaxial fixture fabricated in the operating frequency range from 1 MHz to 30 MHz.

• Proceedings of the Safety Management and Science Conference
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• 2007.04a
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• pp.27-33
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• 2007

There are many reason for unsafety action without safety operation. The reason is no standard safety operation in company or the workers never get a enough education. Standard safety operation is prepared by paper for accurate directions and orders and operators must read the paper to prevent an error of action. Also an essential particular is safety of equipment and machine must be assumed to establish standard safety operation then safety of operations will be possible.

• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.355-358
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• 2008

In the current GPON market and standard, the line bit rate requirement is changing from 1.25 Gbps to 2.5 Gbps. We fabricate a 2.5 Gbps burst-mode receiver with commercially available blocks and optimize it with an APD bias control. A burst-mode measurement setup is made for the full compliance test with the GPON standard. The device meets the partially defined 2.5 Gbps specs in the current ITU G.984.2 standard, also, supports 1.25 Gbps specs for the coexistence issue in an access network. The full-compliant measurement values can be used as a guideline for fixing "for further study" specs in the current GPON standard at 2.5 Gbps.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.4 no.5
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• pp.27-42
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• 1981

The object of this paper is to Study the work measurement which is one of the principal technique in work study for the improvement of Productivity in the foundry industry. Most of domestic mechanical enterprise using the expensive foreign machinerise is inoufficient for the standardization of the operation method and time. Therefore, the improvement of operation and productivity through the introduction of the work measurement is an urgent task. Therefore, this paper is contribute to the improvement of operation and to reduce the loss time through the application of the work measurement based on the case study conducted at W-Foundry Corporation. The summary of this study is follows; 1. The measurement of operation efficiency can be accomplished by the standard time. 2. The detailed causes and counter-proposal of loss time can be established, 3. More than 50% of loss time is attributed to c/p.