• Title/Summary/Keyword: Ko Seok-Kyu

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First Record of Holothurian Symbiotic Crab Asthenognathus inaequipes (Decapoda: Brachyura: Varunidae) from Korea

  • Lee, Seok-Hyun;Lee, Kyu-Hyun;Ko, Hyun-Sook
    • Animal Systematics, Evolution and Diversity
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    • v.26 no.3
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    • pp.337-339
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    • 2010
  • A hole dwelling holothurian symbiotic crab was collected in the low tidal mark in Namhae Island. The crab was identified as Asthenognathus inaequipes Stimpson, 1858 and found to be new to Korean waters. The species was briefly illustrated and described.

First Records of Two Pilumnid Crabs (Crustacea: Decapoda) Collected from Jejudo Island, Southern Korea

  • Lee, Seok-Hyun;Lee, Kyu-Hyun;Ko, Hyun-Sook
    • Animal Systematics, Evolution and Diversity
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    • v.27 no.2
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    • pp.191-196
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    • 2011
  • Two pilumnid species, Echinoecus nipponicus and Zehntneriana amakusae, are described and illustrated from Jejudo Island, southern Korea. These species are recorded for the first time in Korea, and Z. amakusae is the sole representative of the subfamily Rhizopinae of the family Pilumnidae.

Gamma Knife Radiosurgery in Patients with a Hypothalamic Hamartoma Associated with Intractable Gelastic Epilepsy : Report of Three Cases

  • Ko, Che-Kyu;Hong, Seok-Ho;Ko, Tae-Sung;Lee, Jung-Kyo
    • Journal of Korean Neurosurgical Society
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    • v.39 no.1
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    • pp.58-60
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    • 2006
  • Hypothalamic hamartoma[HH] is an unusual nonneoplastic developmental lesion associated with gelastic epilepsy and precocious puberty, mostly found in children. Although open surgery has been attempted when antiepileptic medication failed to control seizures, its deep location and surrounding vital structures often rendered surgery unsuccessful. We describe the outcome of gamma knife radiosurgery in three children with a HH associated with gelastic epilepsy and reviewed the literature for a possible therapeutic mechanism.

Electromagnetic field analysis and performance characteristics of PMSM/G with Halbach magnetized array rotor (Halbach 자화 배열 회전자를 갖는 영구자석 동기 전동발전기의 전자기적 해석 및 성능 특성)

  • Jang, Seok-Myeong;You, Dae-Joon;Ko, Kyoung-Jin;Choi, Sang-Kyu
    • Proceedings of the KIEE Conference
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    • 2008.04c
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    • pp.86-88
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    • 2008
  • The rotational loss is one of the most important problems for the practical use of the high power Flywheel Energy Storage System (FESS). This rotational loss is divided as the mechanical loss by windage and bearing and iron loss by hysteresis loop and eddy current in the part of the magnetic field. So, In this paper, a double-sided PMSM/G without the iron loss is designed by analytical method of the magnetic field and estimation of the back-EMF constant represented as the design parameter. This design model consists of the double-sided PM rotor with Halbach magnetized any and coreless 3-phase winding stator. The results show that the double-sided PMSM/G without iron loss can be applicable to the high power FESS.

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Design of Ultra High-Speed Micro-Scale Permanent Magnet Machine for Maximum Output Power Generation (최대 출력을 위한 초소형/초고속 영구자석 동기기의 설계)

  • Jang, Seok-Myeong;Ko, Kyoung-Jin;Choi, Jang-Young;Park, Ji-Hoon;Kim, Hyun-Kyu
    • Proceedings of the KIEE Conference
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    • 2008.04c
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    • pp.80-82
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    • 2008
  • This paper deals with the design of an 870 krpm class high-speed permanent magnet synchronous generator (PMSG) applied to micro turbine system. Since space where the high-speed PMSG coupled with the micro turbine occupies in the system is strictly limited, the work described in this paper is motivated by the desire to make maximum output power of the generator considering the rotor and stator structures, winding methods and bearing system under restricted space.

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Harmonics-based Spectral Subtraction and Feature Vector Normalization for Robust Speech Recognition

  • Beh, Joung-Hoon;Lee, Heung-Kyu;Kwon, Oh-Il;Ko, Han-Seok
    • Speech Sciences
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    • v.11 no.1
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    • pp.7-20
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    • 2004
  • In this paper, we propose a two-step noise compensation algorithm in feature extraction for achieving robust speech recognition. The proposed method frees us from requiring a priori information on noisy environments and is simple to implement. First, in frequency domain, the Harmonics-based Spectral Subtraction (HSS) is applied so that it reduces the additive background noise and makes the shape of harmonics in speech spectrum more pronounced. We then apply a judiciously weighted variance Feature Vector Normalization (FVN) to compensate for both the channel distortion and additive noise. The weighted variance FVN compensates for the variance mismatch in both the speech and the non-speech regions respectively. Representative performance evaluation using Aurora 2 database shows that the proposed method yields 27.18% relative improvement in accuracy under a multi-noise training task and 57.94% relative improvement under a clean training task.

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Analysis on Eddy Current Losses of High Speed Permanent Magnet Synchronous Motor for Turbo Compressor according to Voltage Source Driving (전압 구동 방법에 따른 터보 압축기용 초고속 영구자석 동기 전동기의 회전자 손실 해석)

  • Jang, Seok-Myeong;Kim, Hyun-Kyu;Ko, Kyoung-Jin;Lee, Sung-Ho;Hong, Young-Hee
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.712_713
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    • 2009
  • This paper deals with the analysis on eddy current looses of high speed permanent magnet synchronous motor (PMSM) for turbo compressor according to voltage source driving. This paper presents analytical procedures for calculation of the eddy current losses using Poynting theorem. On the basis of the magnetic vector potential and a two-dimensional (2-D) cylindrical coordinate system, this paper derived analytical solutions of the eddy current looses using phase current analysis. The eddy current losses of each harmonic obtained by fast Fourier transform (FFT) analysis of phase current are with results obtained from finite-element method (FEM).

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