• 제어로봇시스템학회논문지
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• 제20권10호
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• pp.1023-1029
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• 2014

In this paper, we propose an SPDR (Smith Predictor for Disturbance Reduction) scheme to improve the temperature control by reduction of the disturbance in ROT process with measurement delay. The proposed controller is a combination of Astrom's modified Smith predictor with a disturbance reduction controller and a grey predictor. The grey prediction is used to calculate the inverse of the measurement delay and to predict future variations and tendencies of system output. The simulation results demonstrate the successful performance of the proposed disturbance reduction controller and enhance the robustness of the proposed control scheme.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권4호
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• pp.234-234
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• 2004

Measuring ground resistance has been a popular method of evaluation of the grounding electrode performance. If some portions of grounding electrodes are lost by corrosion, aging or other reasons, consequent deteriotation of the grounding performance would be resulted. It is one of the reasons why it is required to evaluate the performance of grounding systems regularly. However, in case of the electric facilities with multi-grounded system such as power substations with multi-grounded overhead ground wires and/or distribution line neutrals, it is practically difficult to disconnect neutrals or skywires from the substation grounding mesh for the ground resistance measurement. In this paper, a method for the grounding performance measurement of multi-grounded systems, which is based on the measuring ground current distributions, has been proposed. A field test results has shown the validity of the proposed test method.

• 제어로봇시스템학회논문지
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• 제3권6호
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• pp.613-618
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• 1997

In this paper, we designed a line CCD camera for a flying image, which is composed of a line CCD sensor(2048 cells) and a rotating mirror, and investigated its optical properties. We also made the 3-D image from the flying image which is made of 2-D image being juxtaposed to 1-D images obtained by the camera, and performed the calibration to acquire high precision 3-D data. As a result, we obtained the 3-D measurement system using the slit type of laser projector is available to measure the high precision shape of objects.

• 제어로봇시스템학회논문지
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• 제8권5호
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• pp.407-412
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• 2002

A measurement device for gas concentration and flow rate using hot wire is developed for the utilization in industrial applications. The device has two cells of measuring and reference, and a bridge circuit is installed to detect electric current through the hot wire in the cells. An amplification of the signal and conversion to digital output are conducted for the on-line measurement with a personal computer. The flow rate of air and carbon dioxide gas is separately measured for the performance examination of the device. Also, the concentration of air-carbon dioxide and carbon dioxide-argon mixtures is determined for the same evaluation. The outcome of the performance test indicates that the accuracy and stability of the device is satisfactory for the purpose of industrial applications.

• International Journal of Computer Science & Network Security
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• 제23권3호
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• pp.130-138
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• 2023

The Smart grids are considered as multi-disciplinary power systems where the communication networks are highly employed. This paper presents optimal wide area measurement system (WAMS) configuration in Nordic power system. The transition from SCADA to WAMS becomes now trend in all power systems to ensure higher reliability and data visibility. The optimization applied in this research considered the geographical regions of the Nordic power system. The research considered all the devices of WAMS namely phasor measurement units (PMUs), phasor data concentrators (PDCs) and communication links. The study also presents two scenarios for optimal WAMS namely base case and N-1 contingency as different operating conditions. The result of this research presents technical and financial results for WAMS configuration in a real power system. The optimization results are performed using MATLAB 2017a software application.

• 한국안전학회지
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• 제28권1호
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• pp.24-28
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• 2013

This article evaluates the accuracy of noise measurements for 37 noise measurement applications for iPhone 4 and iPhone 3Gs. Noise levels were measured using simultaneously a precision sound level meter and iPhones installed noise measurement applications at the levels of 70 dB, 80 dB and 90 dB at 1,000 Hz. Measurement errors were estimated by subtracting two measurements between iPhone and sound level meter. It was found that measurement errors of 34 applications(89.2%) were greater than ${\pm}2$ dB which is the maximum allowable error range for the Type II sound level meter. It was only 4 applications that measurement errors lie within ${\pm}2$ dB error range. There was no significant differences among measurements with four iPhone 4s. However, there were significant differences between the measurements with iPhone 4 and iPhone 3Gs using the same application. It was due to the different hardware specifications such as microphone. Therefore, noise measurement applications, for example, which has to utilize hardware of the smartphone, should be programmed to identify hardware specifications and to adopt appropriate correction factors upon hardware specifications. In conclusion, it is necessary to check accuracy and validity before using the noise measurement applications for iPhones. Also, it was suggested that it should develop an evaluation guideline or protocol on accuracy testing for the measurement applications using a smartphone.

• 한국전자통신학회논문지
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• 제12권5호
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• pp.755-762
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• 2017

철도통신에서 데이터의 전송속도를 향상시키고 신뢰성 있는 데이터 전송을 위해 LTE기반 철도 무선통신시스템에 대한 연구가 진행되고 있다. 본 논문에서는 LTE기반의 철도 무선통신시스템의 테스트베드에 대해 소개한다. 테스트베드상에서 무선통신시스템을 이용하여 전계강도, 통신 도달거리, 통화설정시간, 핸드오버 성공률, 데이터 전송속도 등과 같은 기본적인 통신성능 측정결과에 대해 소개한다. 이 결과를 바탕으로 향후 시스템 상용화에 필요한 사항들에 대해 논의한다.

• Smart Structures and Systems
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• 제13권6호
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• pp.927-942
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• 2014

Structural displacement is an important indicator for assessing structural safety. For structural displacement monitoring, vision-based displacement measurement systems have been widely developed; however, most systems estimate only 1 or 2-DOF translational displacement. To monitor the 6-DOF structural displacement with high accuracy, a vision-based displacement measurement system with a uniquely designed marker is proposed in this paper. The system is composed of a uniquely designed marker and a camera with a zooming capability, and relative translational and rotational displacement between the marker and the camera is estimated by finding a homography transformation. The novel marker is designed to make the system robust to measurement noise based on a sensitivity analysis of the conventional marker and it has been verified through Monte Carlo simulation results. The performance of the displacement estimation has been verified through two kinds of experimental tests; using a shaking table and a motorized stage. The results show that the system estimates the structural 6-DOF displacement, especially the translational displacement in Z-axis, with high accuracy in real time and is robust to measurement noise.

• 한국가시화정보학회지
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• 제20권2호
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• pp.86-92
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• 2022

Pipe failure due to thermal fatigue and environmental regulations are increasing the importance of pipe monitoring systems in industrial plants. Since most pipe monitoring systems are focus on external crack inspected, it is necessary to temperature and concentration measuring monitoring system inside the pipe. These systems have spatial uncertainty due to sample inspection by one-point measurement. In addition, real-time measurement is not possible due to the limitation of time delay due to contact measurement. In this study, CT-TDLAS (Computed tomography-Tunable diode laser absorption spectroscopy) apply to overcome the limitations of existing methods. Lasers exhibiting an absorption response at a wavelength of 1395 nm were arranged in a lattice pattern on measuring cell. It showed that the inside of the pipe changed to an unstable combustion state over time.

• 경영과학
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• 제26권1호
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• pp.137-159
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• 2009

An organizational performance measurement practice is a function of performance measurement system and performance management system they are currently employing, and its quality is determined by evaluating the followings in a comprehensive manner: first, if they are measuring right things; second, if they are measuring in a right way; third, if they are actively facilitating a process of data collection, structuring, analysis, interpretation, and dissemination; and fourth, if they are using performance measurement results for the primary purposes of performance measurement. This study proposes a diagnostic framework for evaluating the performance measurement practices of public broadcasting which include the qualities of performance measurement and performance management, and develop a structured questionnaire for that purpose. The framework proposed in this study does not serve only as a useful tool for public broadcasting to revise their respective performance measures and performance measurement systems, but it also make their respective performance measurement practices a strategic management tool as well as an operational management one.