• Title/Summary/Keyword: Ko Seok-Kyu

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Experimental Verifications and Electromagnetic Characteristics Analysis of Multi-Pole Permanent Magnet Generator for Small-Scaled Wind Power System (소용량 풍력시스템을 위한 다극 영구자석형 발전기의 전자기적 특성 해석 및 실험적 검증)

  • Jang, Seok-Myeong;Ko, Kyoung-Jin;Kim, Hyun-Kyu;Choi, Jang-Young;Yoon, Gi-Gap
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.609_610
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    • 2009
  • This paper deals with experimental verifications and the electromagnetic characteristics analysis of multi-pole permanent magnet (PM) generator for small-scaled wind power system. Field distribution due to PMs and winding current, cogging torque considering skew effect are analyzed. In addition, using the equivalent circuit method and dynamic d-q method, generating performance analysis is performed. Analysis results are validated by comparison with nonlinear finite element analyses and experimental results.

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Analysis on electromagnetic characteristics of linear induction motor using the analytical method (해석적인 방법에 의한 직선형 유도 전동기의 전자기적 특성해석)

  • Jang, Seok-Myeong;Choi, Ji-Hwan;Ko, Kyoung-Jin;Kim, Hyun-Kyu;Kim, Il-Jung
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.804_805
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    • 2009
  • This paper deals with analysis on electromagnetic characteristics of linear induction motor(LIM) using the analytical method. As a analytical method, space harmonics method which is applied to multilayer region is used in this paper. Using the flux density obtained by analytical method, thrust and normal force are calculated through Maxell stress tensor. The results such as flux densitty, eddy current and force are verified by comparison between analytical results and FEM.

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A Controller Design for an Induction Motor Using Fuzzy PI (Fuzzy PI를 이용한 유도전동기의 제어)

  • Park, Seong-Hun;Ko, Chang-Min;Lee, Hyun-Seok;Park, Seung-Kyu;Ahn, Ho-Gyun
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.1725_1726
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    • 2009
  • The purpose for this paper is to obtain the ��$H_{\infty}$ LMI with fuzzy PI controller for induction motor which is nonlinear system. The controller type is PI and the control gains are obtained based on $H_{\infty}$ control problem. The PI controller is considered a part of a plant and the problem is changed to get controller with static gains. The nonlinear system is approximated as several linear systems and combined by using fuzzy technique.

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A Design of Dual Band LNA for RFID Using Varactor Diode (Varactor를 이용한 RFID 이증 대역 LNA 설계)

  • Choi, Jin-Kyu;Ko, Jae-Hyeong;Chang, Se-Wook;Kim, Hyeong-Seok
    • Proceedings of the KIEE Conference
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    • 2008.05a
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    • pp.151-152
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    • 2008
  • In this paper, a dual band LNA (Low Noise Amplifier) with a matching circuit using varactor diode is designed for 912MHz and 2450MHz RFID system. The operating frequency is controlled by the bias voltage applied to the varactor diode. The measured results demonstrate that gain is 13.6dB and 6.8dB at 912MHz and 2450MHz. The measured NF (Noise Figure) is 1.4dB and 3.1dB at 912MHz and 2450MHz, respectively.

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Dual band antenna for RFID application of 433MHz and 2.45GHz (RFID에 적용 가능한 433MHz, 2.45GHz 이중대역 안테나)

  • Chang, Se-Wook;Ko, Jae-Hyung;Choi, Jin-Kyu;Kim, Hyeong-Seok
    • Proceedings of the KIEE Conference
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    • 2008.05a
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    • pp.157-158
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    • 2008
  • In this paper, a dual band microstrip patch Antenna is designed for RFID Application. The antenna shows a good performance at the frequencys, 433MHz and 2.45GHz for the radiation characteristics and input impedance matching as well. The reflection factor is lower than 15dB and a good directivity higher than 3dB is achieved for both frequency.

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The Gene Expression Profile of LPS-stimulated Microglial Cells

  • Sohn, Sung-Hwa;Ko, Eun-Jung;Kim, Sung-Hoon;Kim, Yang-Seok;Shin, Min-Kyu;Hong, Moo-Chang;Bae, Hyun-Su
    • Molecular & Cellular Toxicology
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    • v.5 no.2
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    • pp.147-152
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    • 2009
  • This study was conducted to evaluate the inflammatory mechanisms of LPS-stimulated BV-2 microglial cells. The inflammation mechanism was evaluated in BV-2 cells with or without LPS treated using the Affymetrix microarray analysis system. The microarray analysis revealed that B cell receptor signaling pathway, cytokine-cytokine receptor interaction, Jak-STAT signaling pathway, MAPK signaling pathway, Neuro-active ligand-receptor interaction, TLR signaling path-way, and T cell receptor signaling pathway-related genes were up-regulated in LPS stimulated BV-2 cells. Selected genes were validated using real time RTPCR. These results can help an effective therapeutic approach to alleviating the progression of neuro-in-flammatory diseases.

Task Types and Loads of Railway Worker (열차운용원의 직무유형 및 직무부하)

  • Han, Kyu-Min;Ko, Jong-Hyun;Jung, Won-Dea;Kang, Jung-Seok
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.1204-1208
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    • 2007
  • In order to prevent railway accidents due to human errors which have been recognized to be the most important cause in the railway accidents, human errors should have been controlled based on systematical analysis of the human errors, and countermeasures should be derived to reduce human error probability. Among several factors inducing human errors, task load (or task complexity) is representative. In order to reduce the human error, a systematic analysis should be undertaken to evaluate task load. In this study, task load according to task types of railway worker who are a safety critical staff have been quantitatively analyzed based on NASA-TLX(Task Load Index).

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Analytical Approach for Rotor Loss Prediction of Permanent Magnet Synchronous Generator with Multi-Pole Rotor (다극 회전자를 갖는 영구자석 동기 발전기의 회전자 손실 예측을 위한 해석적 접근)

  • Jang, Seok-Myeong;Kim, Hyun-Kyu;Choi, Jang-Young;Ko, Kyoung-Jin;Sung, Tae-Hyun;Kim, Il-Jung
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.719-720
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    • 2008
  • This paper deals with analytical approach for rotor loss prediction of permanent magnet synchronous generator(PMSG). The rotor losses of synchronous generator are induced by the magnets. Since stator of our model is skewed, slotting effect can be negligible for our PM wind turbine generator. In order to calculate eddy current, this paper derives analytical solutions by the magnetic vector potential. Finally this paper compared analytical result with eddy current density obtained from finite element(FE) calculations using phase current harmonics analysis.

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Comparison and Analysis for Rotor losses of Permanent Magnet Synchronous Generator using Phase Current Harmonic Analysis according to DC and AC Loads (상전류 고조파 분석을 이용한 직교류 부하에 따른 영구자석 동기 발전기의 회전자 손실 특성해석 및 비교)

  • Jang, Seok-Myeong;Kim, Hyun-Kyu;Choi, Jang-Young;Ko, Kyoung-Jin;Lee, Sung-Ho;Kim, Il-Jung
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.721-722
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    • 2008
  • This paper deals with comparison and analysis for rotor losses of permanent magnet synchronous generator using phase current harmonic analysis according to dc and ac load. On the basis of analytical field analysis, the rotor losses are analysed. Particularly, rated speed and ac load and the rated speed and dc load conditions are considered. This paper compared rotor losses considered dc load with rotor losses considered ac load. Although our analytical modes is low speed, the rotor losses must be considered by results.

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Study of dualband filter applying current distribution of microstripline (마이크로스트립 선로의 전류분포를 이용한 이중대역 필터 구현에 관한 연구)

  • Chang, Se-Wook;Ko, Jae-Hyung;Choi, Jin-Kyu;Kim, Hyeong-Seok
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.1420-1421
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    • 2008
  • In this paper, a dual band microstrip filter is designed for RFID Application. Both magnetic and electric coupling structures are implemented to provide high performance passband response. The measured results demonstrate that reflection factor is 20dB and 15dB at 912MHz and 2450MHz. The measured loss is 2.6dB and 2.8dB at 912MHz and 2450MHz, respectively.

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