• Title/Summary/Keyword: 최정환

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중국 동북3성 기점의 물류 활성화 요인분석

  • 임상섭;이병하;최정환
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2023.05a
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    • pp.66-67
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    • 2023
  • 중국은 우리나라의 최대 수출입 무역국가로써 우리나라 경제에 매우 중요한 위치에 있다. 특히 동북3성을 기점으로 물류는 지리적, 정치적, 문화적인 중요성을 가지고 있어 국익의 관점에서 물류 활성화는 필수적인 요소로써 연구가 필요하다. 본 연구는 동북3성을 기점으로하는 해상물류에 영향을 미치는 요인을 분석하고 활성화를 위한 정책적 제언을 하였다.

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A Study on the Operational Characteristics of a Squirrel-cage type Wind Turine Induction Generator (농형 풍력 유도발전기의 운전 특성에 관한 연구)

  • Jang, Sung-Il;Jeong, Jong-Chan;Choi, Jeong-Hwan;Park, Je-Young;Kim, Kwang-Ho
    • Proceedings of the KIEE Conference
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    • 2002.07b
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    • pp.1309-1312
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    • 2002
  • The electric power network paralleled with wind turbine generator may have the negative impacts on the protection, operation, and management caused by the operation of wind turbine generator. Therefore, it is necessary to investigate the operating characteristic of wind turbine generator. This paper describes model of a squirrel-cage type wind turbine induction generator and the soft cut-in connection method for reducing the transient state on power network, and simulates various cases of wind turbine operations. The radial distribution network of IEEE 13-bus are modeled and tested by PSCAD/EMTDC.

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Reinforcement learning Speedup method using Q-value Initialization (Q-value Initialization을 이용한 Reinforcement Learning Speedup Method)

  • 최정환
    • Proceedings of the IEEK Conference
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    • 2001.06c
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    • pp.13-16
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    • 2001
  • In reinforcement teaming, Q-learning converges quite slowly to a good policy. Its because searching for the goal state takes very long time in a large stochastic domain. So I propose the speedup method using the Q-value initialization for model-free reinforcement learning. In the speedup method, it learns a naive model of a domain and makes boundaries around the goal state. By using these boundaries, it assigns the initial Q-values to the state-action pairs and does Q-learning with the initial Q-values. The initial Q-values guide the agent to the goal state in the early states of learning, so that Q-teaming updates Q-values efficiently. Therefore it saves exploration time to search for the goal state and has better performance than Q-learning. 1 present Speedup Q-learning algorithm to implement the speedup method. This algorithm is evaluated. in a grid-world domain and compared to Q-teaming.

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A Study on the STATCOM Application for Efficient Operations of Wind Farm (풍력발전단지의 효율적인 운전을 위한 STATCOM 적용 가능성 연구)

  • 장성일;최정환;박인기;황혜미;최돈만;김광호;유능수
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.52 no.5
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    • pp.250-256
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    • 2003
  • In this papur, the STATCOM (STATic synchronous COMpensator) application for efficient operations of wind farm is described. The wind farm connected with the electric power network is one of good alternative energy sources. However, it would be also highly possible that interconnection of wind farm causes unwanted influences on distribution system operation, protection and control. This paper proposes the STATCOM application for reducing the negative effects from interconnection of wind farm with distribution networks. The simulation results show that STATCOM would be on effective and useful device to resolve the bad influences from wind farm on distribution networks and improve the operational efficiency of wind farm. In the simulation, the radial distribution network of IEEE 13 bus was modeled using PSCAD/EMTDC.

A Study on Speed Control of Induction Motor using Space Vector PWM (공간벡터 PWM을 이용한 유도전동기의 속도제어에 관한 연구)

  • Kim, Young-Gon;Choi, Jung-Hwan;Lee, Seung-Hwan;Kim, Sung-Nam;Lee, Hoon-Goo;Han, Kyung-Hee
    • Proceedings of the KIEE Conference
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    • 1996.07a
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    • pp.476-478
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    • 1996
  • This paper is on speed control of induction motor using space vector PWM. Indirect vector control which controls independantly flux and torque current component in order to drive induction motor, is applied for driving motor. Voltage sourced inverter with space vector PWM is used to generate the practically perfect sinusoidal flux density in induction motor. The appropriateness of speed control is proven by appling IP(Integral-proportional) controller which is known to have a good speed response and still to have less overshoot than the now used PI(Proportional-Integral) controller.

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Development of a Compact Iron-Cored Electronic Current Transformer Based on IEC 61850 (IEC61850 기반 콤팩트형 철심 코어형 전자석 변류기 개발)

  • Kang, Y.C.;Kim, Y.H.;Choi, J.H.;Park, J.M.;Jang, S.I.;Kim, Y.K.;An, Y.H.;Song, I.J.
    • Proceedings of the KIEE Conference
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    • 2008.11a
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    • pp.191-193
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    • 2008
  • This paper describes a compact Iron-cored Electronic Current Transformer(ECT) based on IEC 61850. The ECT developed in this study has the feature of designing the current transformer with a compact iron-core, compensating error due to the nonlinear characteristic of Iron-core, and applying IEC 61850 9-2 for sampled value(SMV). We verify the performance of the innovative product developed in the study in KERI and test the performance of digital communication in the lab.

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A Compact Iron-Cored Electronic Current Transformer Based on IEC 61850 9-2 (IEC61850 9-2 SMV 기반 전자식 변성기 개발)

  • Choi, J.H.;Jang, S.I.;Kim, Y.H.;Kim, Y.K.;Kang, Y.C.;An, Y.H.;Song, I.J.;Lee, N.H.
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.342_343
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    • 2009
  • This paper describes a compact Iron-cored Electronic Current Transformer(ECT) based on IEC 61850 9-2. The ECT developed in this study has the feature of designing the current transformer with compact iron-core, compensating error due to the nonlinear characteristic of iron-core, and applying IEC 61850 9-2 for sampled value(SMV). We test the performance of the product developed in the study in KERI, KEPRI.

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