• Title/Summary/Keyword: 김용하

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Reliability Evaluation of Distribution System Via Analytic Network Process (망상형 의사결정법에 의한 배전계통 신뢰성 평가)

  • Kim, Yong-Ha;Lee, Buhm;Choi, Sang-Kyu
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.50 no.10
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    • pp.447-453
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    • 2001
  • This paper presents the unified reliability evaluation technique of distribution system. To calculate accurate reliabi1ity and reliability indices which can consider line limitation and voltage drop of distribution system, we employed the deterministic evaluation technique with PLOC technique. And to evaluate the distribution system, we presented the evaluating method which is based on Analytic network process. As a result, we can evaluate the distribution system and build the expansion planning of the system considering system load and reliability indices.

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2003년 지자기 폭풍 동안 한반도 상공 전리층 폭풍 관측

  • Jeong, Jong-Gyun;Ji, Geon-Hwa;Kim, Eo-Jin;Kim, Yong-Ha;Jo, Jeong-Ho
    • Bulletin of the Korean Space Science Society
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    • 2009.10a
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    • pp.39.2-39.2
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    • 2009
  • 지자기 폭풍이 발생할 동안 중위도 전리권 전자밀도 변화의 가장 큰 특징은 양전리권 폭풍 또는 음전리권 폭풍이다. 양전리층 폭풍은 정상적인 경우보다 전자밀도가 증가하는 것으로 정의되는데 적도방향 중성바람에 의한 극지방 전자밀도의 중위도로의 이동으로 설명된다. 음전리권 폭풍은 F2 층 고도의 O/N2 증가에 의한 전자소멸로 전자밀도가 낮아지는 것으로 알려져 있다. 우리는 지상 GPS 총전자량 자료와 이를 이용한 전리권 토모그래피 모델 결과, 그리고 이온존데 관측에 나타난 한반도 상공의 전리층 폭풍 양상을 제시하고 토의할 것이다.

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A Motion-Adaptive De-interlacing Method using Temporal and Spatial Domain Information (시공간 정보를 이용한 움직임 기반의 De-interlacing 기법)

  • 심세훈;김용하;정제창
    • Proceedings of the IEEK Conference
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    • 2002.06d
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    • pp.9-12
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    • 2002
  • In this Paper, we propose an efficient de-interlacing algorithm using temporal and spatial domain information. In the proposed scheme, motion estimation is performed same parity fields, i.e., if current field is even field, reference fields are previous even field and forward even field. And then motion vector refinement is performed to improve the accuracy of motion vectors. In the interpolating step, we use median filter to reduce the interpolation error caused by incorrect motion vector. Simulations conducted for various video sequences have shown the efficiency of the proposed interpolator with significant improvement over previous methods in terms of both PSNR and perceived image quality.

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A Study on the Shear Impact Characteristics of Adhesively Bonded Tubular Joints (접착 조인트의 전단 충격특성에 관한 연구)

  • Kim, Yong-Ha;Park, Sang-Kun;Kim, Dong-Ok;Ryu, Yong-Moon;Cheon, Seong-Sik
    • Composites Research
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    • v.25 no.1
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    • pp.14-18
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    • 2012
  • The structural adhesives have the advantage of improving automobile performances and are being applied to joining light weight materials like aluminium and composite. In order to characterize the impact behavior of structural adhesive, instrumented impact tests were performed with respect to pin-ring adhesively bonded joint specimens. Also dynamic FE analysis was carried out using LS-DYNA to compare the results with experiments.

NOx Removal Characteristics by the Dielectric Packed-bed Plasma Reactor (Dielectric packed-bed 플라스마 반응기를 사용한 NOx 제거 특성에 관한 연구)

  • 김응복;김동욱;정영식;최충석;김용하
    • Journal of the Korean Society of Safety
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    • v.16 no.3
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    • pp.41-44
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    • 2001
  • The removal characteristics of nitrogen oxides (NOx) by the dielectric ($Al_2O_3$) packed-bed plasma reactor are experimentally investigated Reactor is packed with 5[mm] diameter $Al_2O_3$ beads, and was desisted to remove NOx at atmospheric pressures from the moving pollution source such as diesel automobile. The experiments were conducted for applied voltages from 5 to 10[kV], flue gas rate from 2 to 5[l/min] and frequency from 0.5 to 2[kHz]. The NOx removal efficiency significantly increasing with increasing applied voltage. Especially removal rate significantly increased with increasing frequency. However, in this experiment discharged poler n relatively high.

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A Study on Direct Load Control including Unit Commitment (DLC와 기동정지계획의 연계방법에 관한 연구)

  • Lee, Buhm;Kim, Yong-Ha;Choi, Sang-Kyu;Kim, Hyung-Jung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2001.10a
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    • pp.713-716
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    • 2001
  • This paper describes Direct load control(DLC) method including unit commitment. To consider the unit commitment on DLC, 3-Dimensional dynamic programming as a new unit commitment method is developed. And, this method is applied to DLC. As result, optimization of operating schedule with DLC is possible. This method is applied to the test system, and usefulness of the method is verified.

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A Study on Development of Power Transfer Capability Calculation Algorithm Considering Transient Stability (과도 안정도를 고려한 수송능력 산정 알고리즘의 개발에 관한 연구)

  • Kim, Y.H.;Lee, Buhm;Choi, S.K.;Jo, S.L.;Lee, J.G.;Oh, S.H.;Kim, D.K.
    • Proceedings of the KIEE Conference
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    • 2003.07a
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    • pp.95-97
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    • 2003
  • The cost losing synchronous through a transient instability is extremely high in modern power systems. This paper presents a power transfer capability calculation algorithm considering transient stability. The theoretical development is straightforward: dynamic equations are converted to numerically equivalent algebraic equation and then integrated into the standard formulation for power transfer capability calculation.

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A Study on Development of Power Transfer Capability Calculation Algorithm Considering Transient Stability (과도 안정도를 고려한 수송능력 산정 알고리즘의 개발에 관한 연구)

  • Kim Yong-Ha;Choi Sang-Kyu;Lee Byum;Cho Sung-rin;Oh Seok-Hyun;Kim Dong-keun
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.55 no.1
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    • pp.24-28
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    • 2006
  • This paper presents a power transfer capability calculation algorithm considering transient stability, The theoretical development is straightforward: dynamic equations are converted to numerically equivalent algebraic equation and then integrated into the standard formulation for power transfer capability calculation. The proposed method is applied to IEEE-24 Reliability Test System and the results shows the effectiveness of the method.

Separation of Magnetic/non-Magnetic Particles by an Electromagnetic Fluidized Bed (전자석 유동층에 의한 자성/비자성 입자의 분리)

  • 김용하;서인국
    • Resources Recycling
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    • v.6 no.1
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    • pp.17-22
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    • 1997
  • An electromagnetic fluidized bed was proposed for the continuous separation of magnetic particles from the fine a admixtures with nonHmagnetic particles. The effects of operating variables on the magnetic fraction in the separated p particles were examined, including superficial gas velocity, mixing fraction of magnetic particles (= 100-mixing fraction of n non-magnetic particles) in the admixture, and electric current supplied to the electwmagnet. It was found that the s separation was possible when a magnetic force formed by the electromagnets works on the magnetic particles over the hydrodynamic force caused by a gas stream for fluidizing the fine admixture.

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Development of Optimal Substation Expansion Planning Method using ANP (ANP에 의한 최적 변전소 신.증설계획법의 개발)

  • Kim, Yong-ha;Lee, Buhm;Choi, Sang-kyu
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.8
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    • pp.385-390
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    • 2002
  • This paper presents a substation expansion planning method with quantitative analysis using ANP. To calculate the reliability factor and economy factor of the system, reliability indices and total construction cost is used. With these factors, new ANP model which select the best plan either economy or reliability among various alternatives is developed. This model can assist the decision making for the system planner. The usefulness of the method is verified by applying it to the large-scaled distribution system.