• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.144-147
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• 1987

An adaptive control algorithm for a plant with unmodelled dynamics is proposed. The upper bounds of the output due to the unmodelled dynamics and measurement noise is assumed to be known. Linear programming is used in estimating the bounds of plant parameters. Projection type algorithm is used in estimating the plant parameter with these bounds. This algorithm is nearly the same as those proposed by Kreisselmeier or Middleton except that the bounds are computed by linear programming. The stability of the proposed algorithm Can be proved in nearly the same way as that of Middleton. Simulation results show that the proposed algorithm gives better parameter convergence and smaller overshoot in the plant output than the algorithm without computing the bounds of plant parameters by linear programming.

• Journal of Magnetics
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• 제17권3호
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• pp.206-209
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• 2012

Peak interval for reversible permeability is presented for nondestructively evaluating the remanent life of 1Cr-0.5Mo steel. The method to measure the peak interval of reversible permeability is based on the value of reversible permeability is the same as the differential value of the hysteresis loop. The measurement principle is based on the first harmonics voltage induced in a sensing coil using a lock-in amplifier tuned to a frequency of the exciting voltage. Results obtained for the peak interval of reversible permeability and Rockwell hardness on the aged samples decrease as aging time and the Larson-Miller parameter increase. We could estimate the remanent life of 1Cr-0.5Mo steel by using the relationship between the peak interval of reversible permeability and the Larson-Miller parameter, nondestructively.

• 터널과지하공간
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• 제12권4호
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• pp.268-276
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• 2002

In this study, a 3D coordinate measurement system equipped with a laser displacement meter for digitizing rock joint surface was established and the digitized data were used to calculate several roughness parameters. The parameters used in this study were micro avenge inclination $angle(i_{ave})$, average slope of joint $asperity(SL_{ ave})$, root mean square of $i-angle(i_{rms})$, standard deviation of height(SDH), standard deviation of $i-angle(SD_i)$, roughness profile $index(R_P)$, and fractal dimension(D). The relationships between the roughness parameters based on the digitzation of the surface profile were analyzed. Since the measured value varied according to the degree of reflection and the variation of colors at the measuring point, rock joint surface was painted in white to minimize the influence of the surface conditions. The comparison of the measured values and roughness parameters before and after painting revealed the better consequence from measurement on the painted surfaces. Also, effect of measuring interval was studied. As measured interval was increased, roughness parameters were exponentially decreased. The incremental sequence of degree of decrease was $SDH\; i_{ave},\; i_{rms},\; SD_i,\;and\; R_ p-1$. As a result of comparison of parameters from pin-type measurement system and laser type measurement system, all value of parameters were higher when laser-type measurement system was used, except SDH.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1530-1533
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• 2005

Total 12 units of high power klystron-modulator systems as microwave source is under operation for 2.5-GeV electron linear accelerator in Pohang Light Source(PLS) linac. RF power and beam power of klystron are precisely measured for the effective control of electron beam. A precise measurement and measurement equipment with good response characteristics are required for this. Input power of klystron is calculated from the applied voltage and the current on its cathode. Tiny measurement error severely effects RF output power value of klystron. Therefore, special care is needed to measure precise beam voltage. Capacitive voltage divider(CVD) unit is intended for the measurement of beam voltage of 400 kV generated from the pulsed klystron-modulator system. Main parameter to determine the standard capacitance in the high arm of CVD is dielectric constant of insulation oil. Therefore CVD should be designed to have a minimum capacitance variation due to voltage, frequency and temperature in the measurement range. This paper will discuss the analysis of capacitive voltage divider for a pulsed high-voltage measurement, and the empirical relations between capacitance and oil temperature variation.

• Applied Microscopy
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• 제29권1호
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• pp.75-81
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• 1999

본 실험에서 얻어진 결론을 요약하면 아래와 같다. (1) 저진공도의 sputter coater를 이용하여 Au 내부 표준시편을 제작하는 최적 조건은 9mA의 전류로 100 초간 coating하는 것이다. (2) 고진공도의 evaporation coater를 이용하여 Al 내부 표준시편을 제작하는 최적 조건은 7kV의 전압으로 10분간 coating하는 것이다. (3) Au 내부 표준시편을 이용하여 측정한 홍주석 격자상수 값의 측정오차는 정밀도가 1.2% 이하이고, 정확도는 0.3% 이하이다. (4) Au 내부 표준시편을 이용하여 측정한 알바이트 장석 격자상수 값의 측정오차는 정밀도가 0.5% 이하이고, 정확도는 1.1% 이하이다. (5) 내부 표준시편을 사용하여 격자상수를 측정할 때 가장 심각한 오차는 전자회절도형의 거리 및 각도 측정시 발생한다. 체계적인 측정 방법과 정밀도 높은 측정 도구의 사용이 필요하다. (6) 시료나 TEM 조건 때문에 분말 XRD 방법이나 수렴성빔 전자회절법으로 격자상수를 구할 수 없는 경우에는 내부 표준시편을 이용한 TEM 격자상수 측정법이 좋은 대안이 된다.

• 한국유체기계학회 논문집
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• 제19권2호
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• pp.5-10
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• 2016

Gas flow measurement in a closed duct was performed using multi-point Pitot tubes. Measurement uncertainty was assessed for this measurement method. The method was applied for the measurement of air flow into a gas turbine engine in an altitude engine test facility. 46 Pitot tubes, 15 total temperature Kiel probes and 9 static pressure tabs were installed in the engine inlet duct of inner diameter of 264 mm. Five tests were done in an airflow range of 2~10 kg/s. The flow was compressible and the Reynolds numbers were between 450,000 and 2,220,000. The measurement uncertainty was the highest as 6.1% for the lowest flow rate, and lowest as 0.8% for the highest flow rate. This is because the difference between the total and static pressures, which is also related to the flow velocity, becomes almost zero for low flow rate cases. It was found that this measurement method can be used only when the flow velocity is relatively high, e.g., 50 m/s. Static pressure was the most influencing parameter on the flow rate measurement uncertainty. Temperature measurement uncertainty was not very important. Measurement of boundary layer was found to be important for this type of flow rate measurement method. But measurement of flow non-uniformity was not very important provided that the non-uniformity has random behavior in the duct.

• 품질경영학회지
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• 제24권3호
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• pp.145-159
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• 1996

In today's organization, measurement plays a crucial role in helping improve process or quality. In this paper, we review the measurement error study, classical gauge repeatability and reproducibility study, and designed experiment suited for the determination of the measurement capability. Measurement error study is very simple to use but is rather crude. Hence, it should be used as a preliminary study to determine whether further study is necessary. Classical gauge repeatability and reproducibility (GR&R) study is the most common technique for evaluation of gauge capability. It calculates a percentage that relates the repeatability, reproducibility, and overall R&R to the specification range for the parameter measured. Hence, the individual repeatability and reproducibility statistics will indicate the area on which to concentrate. However, GR&R study only gives a point estimate of each component, which leaves a room for improvement. It is always good to integrate the use of control charts to ascertain the statistical stability of the measurement process. The tools of statistical experimental design are available for a comprehensive design and analysis of the measurement process. Hence, in this paper, we present gauge capability analysis as an experimental design problem and compare it with the classical GR&R study.

• 동력기계공학회지
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• 제15권5호
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• pp.91-96
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• 2011

The handling ability of containers at the terminal strongly depends on the performance of the cargo handling system such as RTGC(Rubber Tired Gantry Crane) and RMGC(Rail Mounted Gantry Crane). This paper introduces a guide line measurement system on the operating condition, in which two camera are installed to detect the guide line. Because the line tracking is the basic technique for control system design of RTGC, it is necessary to develop a useful and reliable measurement system. If the displacement and angle of the RTGC relative to a guide line as the trajectory to follow is obtained, the position of RTGC is automatically calculated. Therefore, in this paper, a camera-based measurement system is introduced. The proposed measurement system is robust against light fluctuation and cracks of the guide line. This system consists of two camera and a PC which are installed at the lower side of the RTGC. Two edges of the guide line are detected from an input image taken by the cameras in the moving state, and these positions are determined in a Hough parameter space by using the Hough transformation method. From the experimental results, the accuracy and usefulness of the proposed system is evaluated by comparing other instruments.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1711-1714
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• 2006

Anchoring energy of liquid crystals on solid substrates is a key parameter in liquid crystal technology. A nonperturbative method of its measurement by dynamic light scattering on thermal orientational fluctuations is presented, The ratio of the zenithal and azimuthal anchoring coefficients is shown to be equal to the ratio of the orientational elastic constants.

• 한국전자현미경학회:학술대회논문집
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• 한국현미경학회 1995년도 제26회 춘계학술대회 연제초록
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• pp.58-58
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• 1995