• Communications of the Korean Institute of Information Scientists and Engineers
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• v.34 no.9
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• pp.47-51
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• 2016

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.554-555
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• 2014

제어 시스템은 과도 응답을 거쳐 입력 명령에 근접하는 정상 상태 응답이 출력되도록 설계되기 때문에 동적시스템으로 정의된다. 이러한 동적시스템을 설계할 때 과도 응답과 정상 상태 오차, 안정도의 보장은 시스템 설계 시 가장 기본적으로 고려되어야 하는 요소이다. 본 논문에서는 동적시스템의 응답 특성 개선을 위하여 PI제어기와 IP제어기의 특성을 동시에 이용할 수 있는 혼합제어기를 설계하고 PMSM의 속도제어기에 적용하여 응답 특성을 시뮬레이션으로 확인하였다.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.574-581
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• 1999

비선형 임계속도를 주행시험대를 이용하여 측정하였으며 비선형 임계속도가 관성에 의한 과도 현상이 아님을 확인하기 위하여 주행속도를 연속 그리고 불연속적으로 감가속 하면서 선형 및 비선형 임계속도를 측정하였다. 또한 차량의 안정성을 간편하게 예측할 때 대차모델만을 사용하던 종래의 방법이 타당한지 확인하였으며 차량의 임계속도와 응답주파수를 예측하기 위하여 산업체에서 사용되던 간편 식들의 정확성을 검토한 결과 다음의 결과를 도출할 수 있었다. (중략)

• Journal of the Korean Society for Railway
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• v.16 no.4
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• pp.305-310
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• 2013

In general, it is difficult to measure dynamic responses of a bridge with stepwise increasing speed of a train during commercial service on a high speed railroad. However, before opening the 2nd stage of the Gyeongbu high speed railroad, there was an opportunity for field tests and measurements of the bridge with stepwise increasing speed(from 170km/ h to 315km/h). The measured responses were compared with the results of a developed bridge/train interaction analysis. Although good agreement was found throughout almost the entire range of speeds, relatively large differences were found in the vicinity of the critical speed at which resonance behavior of the bridge occurs. To investigate the cause of this, reanalyses are performed with re-estimated damping ratios from field tests.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.1
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• pp.27-35
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• 1998

In this paper, we propose a novel spectral-chopping model of Class-II$(1+D)^2$ -PRS system which reveals improved spectral efficiency. We build up the model having spectrum chopped by the amount of Nyquist over-rate, and then compare its characteristics with the conventional model in both the time-domain and the frequency-domain. When the transmission system operates above the Nyquist rate, the new model has better performance than the conventional PRS using its inherent speed-tolerance. According to our investigations, Class-II PRS shows more excellent effect in the spectral-chopping method than Class- I and W types analyzed previously. We ascertain that the over-rate of 26.675 obtained by the inherent speed-tolerance could be improved upto 40% using spectrum-truncation. These effects come from the fact that the raised-cosine spectrum of Class-II PRS has smaller Boss of frequency component and energy than any other types for the same amount of truncation. In order to validate these theoretical results, we present their sidelobe-trends confirming cancellation effects at the sampling instants and some experimental results showing their patterns of eye-openings and spectra.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2585-2588
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• 2003

2 관성 공진계는 마른 응답을 위해 제어이득을 크게 하면 공진에 의해 축비틀림 진동이 일어나는 경우가 많다. 본 논문에서는 반복 학습 제어기법을 활용하여 불확실한 모델 계수를 포함하는 2 관성 공진계의 진동억제를 시도한다. 2관성 공진계의 경우 제어 대상이 되는 부하측 속도는 학습 제어로 직접 적용하기가 힘들고 또한 측정 또한 어렵다. 본 논문에서는 부하측 속도와 전동기측 속도간의 관계를 이용하여 직접 부하측 속도를 제어하는 대신 전동기측 속도를 제어하여 간접적으로 부하측 속도를 제어하였다. 제안된 방식은 전형적인 2 관성 공진계에 모의 실험을 통해 적용되었고, 정확한 모델이 없이도 진동 없는 마른 응답특성을 보여준다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.6
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• pp.21-28
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• 2007

Using multi-resolution, the mutiresolution proportional-integral-derivative(MRPID) controller functions as a filter to eliminate noise and disturbance which are included in error signals. If the sampling frequency is high, the response time will be delayed because of the remaining high frequency component although the overshoot is removed. However, if the sampling frequency is low, the response time will be enhanced by getting rid of signal components while the overshoot is increased. In this paper, the sampling frequency tuning method is used the response of the proportional integral derivative(PID) controller and the MRPID controller, and the parameter tuning method is considered the characteristic of the MRPID controller. The proposal method is verified by computer simulations.

• Fire Science and Engineering
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• v.17 no.2
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• pp.6-9
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• 2003

Recently, forced ventilating air conditioning system has been widely used in modern buildings. However, It is obvious that this kind of system may affect on the response of fire detectors at real fire incidents, especially, on the ionization smoke detector, which is critically influenced by air stream. Therefore we studied to verify the response characteristics of air stream by ionization smoke detector for the design of facilities in practice. In this study, experiments were executed to examine the correlation between air velocity and the ionization detector's responses with var-ious air velocity and smoke densities in the simulated test room. As a result of experiments, ionization detector's operating time is in reverse proportion to air velocity. And the detector shows more sensitive reaction when the velocity of smoke stream increase over 60 cm/s. In addition, it was shown that ionization smoke detector is more sensitive to smoldering fires in paper than that in petro-chemicals.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.538-539
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• 2008

유비쿼터스 컴퓨팅의 실현을 위해 센서 네트워크 기반의 다양한 위치인식 연구가 수행되었다. 특히 근거리 위치 인식 분야에서는 RSSI를 이용한 위치 인식에 관한 연구가 활발하였으나 RSSI는 통신 환경에 민감하여 균일한 위치 정보 결과를 획득하기 어려우며, RSSI 값을 기반으로 삼각측량 등의 위치 계산을 소프트웨어적으로 처리하기 때문에 응답 속도가 늦다는 단점이 있다. 따라서 최근 Chipcon에서는 CC243x 시리즈에 위치 계산 엔진(Location Engine)을 탑재하여 응답 속도에 대한 종전의 단점을 보완하였으나 여전히 위치 값이 고르지 못한 부분은 개선되지 않았다. 따라서 본 논문에서는 통신 환경으로 인한 위치 정보의 불균등함을 개선하고자 선형 윈도우 알고리즘을 제안한다. 선형 윈도우는 위치 정보에 대한 스무팅을 수행하며, 이를 통해 응답 속도의 저하를 최소화시키면서 위치 변화를 고르게 한다.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.1
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• pp.21-28
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• 1999

The objective of the study is to develop attenuation equations of the ground motions in the southern part of the Korean peninsula. The earthquake source characteristics and the medium properties were estimated from available instrumental earthquake records and used as input parameters. The peak ground accelerations(PGA) and pseudo-velocity response spectra(PSV) were simulated by the random vibration theory. The attenuation equations for the PGA and PSV were constructed in terms of local magnitudes and hypocentral distances.