• Title/Summary/Keyword: 김대성

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A Current Differential Relaying Algorithm for Power Transformers Using the Difference of a Differential Current (차전류의 차분을 이용한 변압기 보호용 전류차동 계전방식)

  • Kang, Y.C.;Kim, D.S.;Lee, B.E.;Kim, E.S.;Won, S.H.
    • Proceedings of the KIEE Conference
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    • 2002.11b
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    • pp.274-276
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    • 2002
  • This paper proposes a current differential relaying algorithm for power transformers using the third difference function of a differential current. The algorithm observes the instants when the wave-shape of the differential current is changed due to the change of the magnetization inductance. If the value of the third difference is bigger than the threshold, the output of a current differential relay is blocked for a cycle. In the cases of magnetic inrush and overexcitation, the blocking signal is maintained: however, for internal faults, reset in a cycle. The test results clearly show that the algorithm successfully distinguishes internal faults from magnetizing inrush.

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Combustion and Pyrolysis Characteristics of Solid Wastes in a 30 kg/hr Capacity Pyrolysis Melting Incinerator (30 kg/hr 급 열분해 용융 소각로에서의 폐기물 열분해/연소/용융 특성 연구)

  • Yu, Tae-U;Kim, Bong-Geun;Yang, Won;Jeon, Keum-Ha;Shin, Dong-Hoon;Park, Sang-Uk;Im, Seong-Jin;Kim, Dae-Seong;Lee, Jin-Ho;Hwang, Jeong-Ho
    • 한국연소학회:학술대회논문집
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    • 2006.04a
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    • pp.172-180
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    • 2006
  • A novel pyrolysis-melting incineration system of reduced scale (30 kg/hr) is and constructed in Korea Institute of Industrial Technology. The incineration process is composed of three parts: pyrolysis, gas combustion and ash melting processes. For each unit process, experimental and numerical approaches including reduced-scale cold/hot flow tests have been conducted to find optimal design and operating conditions. This paper presents major results of these approaches with brief descriptions on the pilot-scale incinerator (200 kg/hr) under construction and future research works.

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Automatic Extraction of Pseudo Invariant Features using Ordinal Rank Algorithm for Radiometric Normalization (Ordinal Rank 알고리즘을 이용한 자동 PIF 추출 - 변화탐지를 위한 상대방사정규화를 목적으로)

  • Han, You-Kyung;Kim, Dae-Sung;Kim, Yong-Il
    • Proceedings of the KSRS Conference
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    • 2008.03a
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    • pp.213-218
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    • 2008
  • 동일 지점을 촬영한 위성영상은 위성의 센서나 영상의 취득 시기, 지형의 상태 등에 따라 그 지점에 나타나는 화소값이 일정하지 않다. 이러한 영상은 영상간 모자이크나 변화 탐지 결과에 영향을 미칠 가능성이 높으므로 방사보정(또는 방사정규화)을 통해 화소값의 차이를 최소화시킬 필요가 있다. 본 연구는 선형회귀식을 적용한 상대 방사정규화에 초점을 맞추고 있으며, 선형회귀식 구성에 필요한 PIF(Pseudo Invariant Feature)를 자동으로 추출하기 위해 Ordinal Rank 알고리즘을 적용하였다. 이 방법을 통해 각 밴드별 후보 PIF를 추출하고, 공통으로 해당되는 최종 PIF를 추출할 수 있었다. RMSE(Root Mean Square Error), Dynamic range, Coefficient of variation 등을 통해 방사보정 후의 결과를 평가해보았다. 영상회귀를 이용한 방사보정알고리즘과의 비교를 통해 제안된 알고리즘이 갖는 장점을 확인하였다.

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A study on the magnetic suspension system for commercial vehicle (상용차용 마그네틱 현가기구 개발에 대한 연구)

  • Ju, Hyung-Jun;Kim, Dae-Sung;Lee, Bong-Hyun;Kim, Jung-In;Kim, Chan-Jung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.04a
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    • pp.409-414
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    • 2011
  • The drivers of commercial vehicle easily feel tired because of a long time driving and bad road condition. Therefore it is very important to make the driver seat comfortable. This paper introduces the suspension system of driver's seat using magnetic force. The combination of linear spring and magnetic force can make nonlinear spring which has optimal stiffness for minimal vibration transmissibility. The vibrations of driver's seat floor are measured in various road condition. And the numerical simulations and experiments are performed to define the optimal parameter of magnetic suspension system.

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Analytical study on High speed Shear forming Process of Lead-acid Battery Grids (연축전지 기판 격자의 고속 전단성형공정 해석적 연구)

  • Kim Dae-sung;Jung Jong-jun;Cho Hyung-chan;Lee Coon-man
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.2 s.179
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    • pp.81-87
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    • 2006
  • This study has been focused on the analysis of high speed shear forming process for lead-acid battery grids. The grid plays an important role of electrical charge. It is necessary to ensure the best battery's performance that the grid should have a best quality. The clearance between punch and die, the velocity of punch and the critical damage value are very important parameters for making a good grid form. The finite element analysis of the shear forming process is carried out by measuring and optimizing these three important parameters. The result of this study concludes that these parameters has a great influence on grid quality.

A Study of Sub-Pixel Detection for Hyperspectral Image Using Linear Spectral Unmixing Algorithm (Linear Spectral Unmixing 기법을 이용한 하이퍼스펙트럴 영상의 Sub-Pixel Detection에 관한 연구)

  • 김대성;조영욱;한동엽;김용일
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2003.04a
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    • pp.161-166
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    • 2003
  • Hyperspectral imagery have high spectral resolution and provide the potential for more accurate and detailed information extraction than any other type of remotely sensed data. In this paper, the "Linear Spectral Unmixing" model which is one solution to overcome the limit of spatial resolution for remote sensing data was introduced and we applied the algorithm to hyperspectral image. The result was not good because of some problems such as image calibration and used endmembers. Therefore, we analyzed the cause and had a search for a solution.

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