• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.5
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• pp.223-229
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• 2023

This Paper propose the method that measure main system parameters for PI(proportional-integral) current control of a.c. motor adopting the vector control technique. For current control, the PI control input is could be tuning by several selective methods. Among the several methods, the method that using the main system parameters, wire resistance and inductance, are frequently used. In this study, the technique to dissect and measure these two system parameters through the results of simple feedback control. This analytic measurement method is measuring parameters step by step dissecting the results of P control using simple proportional feedback gain about the unit step or multiple step reference command. This strategy is an real time analytic measurement method that calculate current control gains of torque component and flux component both for vector control of A.C. motor without introducing the further measurement circuits and complex measuring algorithms.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.4
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• pp.362-367
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• 2017

This study was conducted to compare the particulate removal efficiency of the developed diesel particulate filter using various measurement methods in a high-speed marine diesel engine. A four-stroke mechanical marine diesel engine is used for the test, which has a maximum output of 403 kW and is coupled to an AC dynamometer to control engine speed and load. The test was conducted based on four steady-state engine operating conditions of E3 engine test cycle for the measurement of PM and soot removal efficiency using partial dilution method considered as gravimetric method and filter smoke number method as light absorption method, respectively. As a result of the removal efficiency measurement according to the application of diesel particulate filter, particulate matter was reduced from 76% to 91% and the soot was reduced by more than 90% while meeting the permissible engine back pressure. From these results, the applicability of diesel particulate filter adopted in high-speed marine diesel engines could be confirmed. In addition, based on the result that the particulate removal efficiency varies with different measurement methods, the necessity of unification of these methods could be identified.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.318-319
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• 2020

본 논문은 ICT 융합 기술 분야의 기초가 되는 전자회로의 이론 및 실습을 위한 방법으로 증강현실기반 전자 회로 교육 시스템을 제안 하였다. 제안된 시스템은 기본 전자 소자가 탑재된 하드웨어 모듈과 증강현실 기술을 적용한 모바일 교육 콘텐츠로 실제 회로를 실물로 동작 확인이 가능하며, 증강현실 기반에서 전류의 흐름, 입·출력값 측정값등에 대한 정보를 제공한다. 이에 각 이론 및 실습단계에서 기초 전자 소자 및 전자 회로에 대한 교육을 자기 주도 학습이 가능하도록 하였다.

• Journal of Advanced Navigation Technology
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• v.27 no.2
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• pp.203-208
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• 2023

In this study, we propose a method to improve the precision of contact resistance measurement circuits using constant current method and voltage drop method, and implement a dashboard that monitors the measured data of contact resistance measurement systems through MQTT broker server. The contact resistance measurement system measures the resistance value and transmits the measured value to the MQTT broker server using wireless communications. This developed dashboard uses Node-RED and Node-RED-Dashboard to receive the resistance values of up to four contact resistance measurement systems and show them to user's monitor screen. Users can manage multiple measurement data using a single dashboard and easily interface with other devices through the MQTT broker server. Through the experimental results from real data measurements, the relative standard deviation about precision is improved to average 40.37% and maximum 64.73% respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.12
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• pp.1311-1320
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• 2003

This paper proposed the estimating method of electromagnetic dosimetric reliability at in-vivo and in-vitro experiments. For more accurate consequences of these researches, we have tried to find out any correlations among output power, power density and specific absorption rate(SAR) with the results of in-vivo, in-vitro tests and SAR reports of cellular phone and PDA. In the case of in-vivo tests, the power density has close statistical correlations with SAR value and in the event of in-vitro tests, the output power has considerable statistical correlations with SAR containing duty factor. We analysed the coefficient of determination to estimate the dosimeoic uncertainty. If we use this method before evaluating techniques of measurement and analysis at both in-vivo and in-vitro experiments, we will conduct more accurate reliability test.

• Plant Journal
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• v.13 no.2
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• pp.46-51
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• 2017

In this study, the boiler efficiency and the change of boiler combustion state with the burner operation of the uppermost layer of 870MW opposite fired coal boiler were measured. Test results showed that the boiler efficiency was high in the order of the uppermost layer simultaneous operation of the front and rear burners, the front burner, and the rear burner operation. When the front and rear burners were operated simultaneously, the heat absorption rate of water walls in the boiler furnace was uniform at four side, and the temperature deviation of the left and right steam on the convection front surface decreased. As the heat absorption rate of the boiler improved, the loss of boiler exhaust gas decreased and the coal supply amount decreased by 8 tons/hour compared to the operation of the rear burner. This will contribute not only to the reduction of fuel cost but also to the reduction of greenhouse gas emissions.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.12
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• pp.15-22
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• 2011

Integrated-optic symmetric/asymmetric Mach-Zehnder interferometers at $1.3{\mu}m$ wavelength were studied as sensing part for electric-field measurement system. The devices were simulated based on the BPM software and fabricated utilizing Ti-diffused $LiNbO_3$ channel optical waveguides and lumped-type electrodes. A half-wave voltage of $V_{\pi}$=6.6V and modulation depth of 100% and 75% for a symmetric structure were measured for 200Hz and 1kHz electrical signal bandwidth, respectively. By the way, almost half-maximum power transmission was observed for asymmetric interferometers with ${\pi}$/2 intrinsic phase difference. Expected experimental measurements were observed for 1kHz electrical signal bandwidth.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.12
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• pp.333-338
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• 2020

This paper proposes an augmented reality-based electronic circuit education system as a way for electronic circuit education, which is the basis of ICT convergence technology field. It consists of a hardware module that can identify the actual circuit and a mobile educational content that can check the current flow, input, output, and measured value by applying augmented reality technology. An experiment was conducted on image recognition, which is the main performance, for the purpose of stable operation of the system, and as the experimental method the recognition rate was measured by changing the distance between the hardware module and the mobile device to a certain interval. As a result of the experiment, the recognition rate was 100 percent at a distance of 25[Cm] or higher, and it was confirmed that the recognition rate decreased by 12% at a distance below 25[Cm], which can be said to be the effect of an error that results in image loss taken due to close distance. In the future, we plan to apply the education system presented in this paper to classes, which increases the efficiency of classes and improve students' interest and understanding of the subject.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1991.04a
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• pp.23-27
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• 1991

각종 홀 (음악홀, 극장, 사무실건물)의 공조 덕트계에는 미로형소음챔버가 설 치되는 경우가 많다. 이러한 소음장치를 건물내부에 설치하는 경우에는 건물 설계단계에서부터 소음챔버로 인한 감음양(투과손실 : Transmission Loss)의 예측계산이 중요하다. 그렇지만, 일반적인 소음장치는 그 형상이나 내표면의 흡음조건이 아주 복잡하기 때문에, 현단계에서는 간단한 이론만으로 투과손 실예측이 거의 불가능하다. 지금까지 이 문제에 대해서 유한요소법(Finite Element Method : FEM)을 이용해 검토한 예가 종종 소개되었으나, 대부분 소음챔버의 입구와 출구에서의 임의의 점에 대한 음압비를 투과손실로서 구 하고 있다. 그러나, 소음기자체의 실질적인 투과손실특성을 알기 위해서는 소음기의 입력 파워에 대한 출력파워의 비로서 구하지 않으면 안된다. 따라 서, 본 연구에서는 유한요소법에 의한 복소음향인텐시티(Complex sound intensity)의 수치계산법을 각종소음기 (팽창형, 미로형)의 투과손실해석에 적 용하기 위하여 이론적인 면에서 고찰했으며, 프로그램도 개발하여 모델해석 에 적용하였다. 또한, 위에서 언급된 수치해석법의 타당성의 검증을 위하여, 측정에 의한 투과손실예측방법으로서 크로스스펙트럼(Cross Spectrum)법에 의한 음향인텐시티계측법의 이용에 대해서 이론적으로 고찰했으며, 그 이론 을 기초로 한 축척 모형실험을 병행하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.788-792
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• 2007

국내외의 자동차 메이커는 고효율, 저공해 자동차 개발에 집중하고 있으며, 그 방법으로 하이브리드 자동차가 최우선시 되고 있다. 하이브리드 자동차의 밧데리 팩을 구성하는 핵심 부품 중 하나인 고전압 직류 릴레이는 주행 중 엔진 구동력을 보조하는 구동모터에 전기 에너지를 공급하는 밧데리의 출력을 개폐하는 기기이다. 고전압 직류 릴레이의 개폐 동작시 발생하는 소음은 자동차 운전 중 실내로 유입되어 운전자의 승차감을 떨어뜨리는 요인이 되므로 릴레이의 개폐 동작시 발생하는 소음 저감을 위한 연구가 필요하다. 본 연구에서는 폐로(ON) 동작시 발생하는 소음 저감을 위해 소음원인 충격력을 감소시키기 위한 이중 접압스프링 구조를 제안하였으며, 소음 저감 성능평가를 수행하였다. 먼저 정확한 충격해석을 위해 고전압 직류 릴레이의 최소 동작 전압인 5.9V부터 상시 인가 전압인 12V까지 총 6개의 전압레벨에서 릴레이의 전자력을 측정하였으며, 기존 접압스프링 구조와 이중 접압스프링 구조에 관하여 외연적 탄소성 유한요소 프로그램인 LS-DYNA를 사용하여 충격해석을 수행하였다. 고전압 직류 릴레이의 소음원인 가동전극과 고정전극에서 발생하는 일차 충격력과 가동철심과 고정철심에서 발생하는 이차 충격력을 비교, 평가하였다.