• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.5
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• pp.406-414
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• 2009

To cope with the high power density and low cost in switching power supply, LLC resonant converters with the two resonant tank circuits composed of resonance capacitors and two transformers are proposed in this paper. Each transformers used for the proposed resonant circuits are parallel connected in the primary and series connected in the secondary to reduce the current unbalance. The proposed LLC resonant converters are described and verified on 300W experimental prototype.

• Journal of Electrical Engineering and Technology
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• v.2 no.2
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• pp.280-285
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• 2007

This paper presents a robustly adaptive flux observer for speed-sensorless induction motor control. The proposed approach employs additional robustifying signals to cope with the parametric uncertainties instead of designing an estimator, which has been normally used in power electronic drives. For that, the sliding-mode like adaptive controls are designed and their gain parameters are determined so that the observer dynamics are stable in the sense of Lyapunov, and furthermore they can guarantee the robustness against parametric uncertainties in induction motor systems. Estimated rotor speed is to be used to generate feedback control signal for the speed sensorless vector control system. To show the validity and efficiency of the proposed system, simulation results are presented.

• Journal of radiological science and technology
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• v.4 no.1
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• pp.81-84
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• 1981

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.375-380
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• 2004

Seismic Isolation and Shock/vibration Control Laboratory has performed the National Research Laboratory(NRL) project, 'Design and Application of Control Devices against Earthquake/Shock/Vibration'. In this project, the prototypes of the vibration control devices for structural control against earthquake and wind were developed and verified their performances. And also, the computer programs were developed for the seismic response analysis and the optimum design of the base-isolated structures with vibration control devices. This paper introduces the developed vibration control devices and computer programs.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.211-213
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• 2003

RED 파라미터를 가장 적합하게 설정할지라도 RED 라우터의 처리량(Throughput)이 TD 라우터 보다 획기적으로 향상되기는 매우 어려운 일이다 하지만 REO 라우터를 이용하여 TCP 커넥션들간의 페어니스(Fairness)와 페어니스 향상에 따른 전체 네트워크 이용률(Utilization)을 높일 수는 있다. 본 논문에서는 네트워크 상황에 따라 동적으로 RED 파라미터를 조절하면서 빠르게 안정적인 상태로 적응하는 진보된 RED 알고리즘인 ea-RED(Efficient Adaptive RED)의 성능을 네트워크 시뮬레이션 툴인 NS-2를 이용하여 TD. RED 알고리즘과 다양하게 실험하고 비교 분석한다. 이 실험을 통해 병목구간에서 혼잡이 심할 경우, ea-RED 라우터가 RED나 TD 라우터에 비해 큐를 효율적으로 사용하면서도 보다 높은 페어니스 인덱스 값을 갖는다는 점을 확인할 수 있다.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.393-400
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• 2006

One of the most promising semi-active devices proposed for structural control is magnetorheological fluid (MR) dampers. While many researches are making too much of application to structural control, few of papers are considering how to design the MR dampers having good performance. In this paper, the sub-optimal design procedure for MR dampers is presented. This paper shows that an MR damper having the capacity of about 5,000 N is designed according to proposed procedure, as an exmple.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.243-246
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• 2012

클라우드 컴퓨팅 서비스는 눈부신 발전으로 다양한 서비스가 제공되고 있으며 많은 개인 사용자들이 클라우드 서비스에 가입하여 서비스를 제공받고 있다. 하지만 개인 사용자를 대상으로 제공하는 클라우드 서비스는 사용자의 정보를 요구하고 있으며 제공된 사용자 개인정보가 어떻게 보고되는지 개인 사용자는 확인하기 힘들다. 따라서 사용자의 정보 공개를 최소화하는 시스템이 필요하며 사용자의 정보가 없어도 사용자에 맞춤 서비스를 제공할 수 있는 클라우드 컴퓨팅 접근제어 시스템을 제안하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.972-974
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• 2012

최근 인간의 삶의 질을 높이기 위하여 다양한 분야가 IT 기술과 접목되고 있다. 전 세계적으로 홈 오토메이션 시스템이 각광받고 있으며, 더욱 효율적인 방법을 찾기 위해 M2M(사물간 통신) 및 클라우드 기술이 접목되고 있다. 본 논문에서는 스마트홈에서 경량화된 홈 게이트웨이 구조 제안을 위해 M2M 및 OSGi 등의 관련 기술을 연구함으로써 기존 기법의 문제점을 해결하고 변화하는 환경에 맞는 홈 게이트웨이 솔루션을 제시하기 위한 기반을 마련하고자 한다.

• Journal of Chest Surgery
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• v.51 no.6
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• pp.403-405
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• 2018

This case report concerns a young patient with an extremely rare combination of d-transposition of the great arteries (d-TGA) and anomalous origin of the right subclavian artery. In our patient, the right subclavian artery originated from the pulmonary artery, which is why he did not show reversed differential cyanosis. We conclude that the presence of an aortic arch anomaly should be considered in patients with d-TGA who do not present with reversed differential cyanosis. A further imaging work-up, including computed tomography or magnetic resonance imaging, might be helpful.

• Journal of Drive and Control
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• v.15 no.4
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• pp.61-66
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• 2018

Almost every hydraulic system is equipped with a pressure relief valve, to maintain working pressure of the system at a pre-determined level. Thus, dynamic characteristics of such a relief valve, in conjunction with other hydraulic components, are important in designing the hydraulic control system. The single stage pressure relief valve is dynamically undesirable, due to relatively low viscous damping, that causes high frequency oscillations. This problem is overcome by introducing orifices in the inner pilot line, and drain line. In this study, for the single stage spool type pressure relief valve, the system equations were derived through an adequate linearisation and several simplifications were made, to use the transfer function formulation technique. All coefficients were evaluated and used, to make some results by using Matlab software. Results of analysis are compared with experimental results. In this study, parameters affecting stability of valve design are determined and suggested relative to the design.