• Title/Summary/Keyword: Lee Sam

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Design and Implement Ubiquitous System on Chip for IEEE 802.15.4 WPAN Standard

  • Doo, Kyoung;Kim, Young-Sam;Kim, Sun-Kuk;Lee, Kang-Whan
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.697-698
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    • 2008
  • Ubiquitous Computing System is available anytime, anywhere communications and computing systems, and information sharing and mutual cooperation between computing systems. in addition, For Ubiquitous Computing System, it is need the sensor technology to detect information of users and surrounding environment. For these reason, this paper proposed CRS(Context Recognition Switch) and DOS(Dynamic and Optimal Standard) based Context-awareness system architecture.

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Research on multi-homing handover in hetrogeneous wireless networks for Mobile AP system (이동 AP 시스템을 위한 이종망간 멀티호밍 핸드오버 연구)

  • Kim, Han-Lim;Kim, Sang-Eon;Jin, Jong-Sam;Lee, Seong-Choon
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.699-700
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    • 2008
  • In this paper, we implement Mobile AP system, which has Multihoming function providing vertical handover between WiBro and HSDPA networks. We monitor packet drop in networks during binding updates(BU) and acknowledgement(BA) and analyze handover latency. We propose methodology to reduce handover latency and describe the further development direction of Mobile AP system.

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Receding Horizon Predictive Control for Nonlinear Time-delay Systems

  • Kwon, Wook-Hyun;Lee, Young-Sam;Han, Soo-Hee
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.27.2-27
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    • 2001
  • This paper proposes a receding horizon predictive control (RHPC) for nonlinear time-delay systems. The control law is obtained by minimizing finite horizon cost with a terminal weighting functional. An inequality condition on the terminal weighting functional is presented, under which the closed-loop stability of RHPC is guaranteed, A special class of nonlinear time-delay systems is introduced and a systematic method to find a terminal weighting functional satisfying the proposed inequality condition is given for these systems. Through a simulation example, it is demonstrated that the proposed RHPC has the guaranteed closed-loop stability for nonlinear time-delay systems.

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PHOTOMETRY OF THE 1995-96 ECLIPSE OF ZETA AURIGAE

  • NHA SARAH;LEE YONG-SAM
    • Journal of The Korean Astronomical Society
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    • v.29 no.spc1
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    • pp.243-243
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    • 1996
  • UBV observations have been made jointly at three observatories for the recent eclipse of the long period atmospheric eclipsing binary star Zeta Aur in 1995-6. Observations covered successfully the phases before, during, and after the eclipse enable us to determine the accurate time of mid-eclipse and the duration of the totality. The hypothesis of the expansion of the K supergiant has been tested and the positive conclusion may be derived.

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흠경각루 내부 메커니즘에 대한 고찰

  • Kim, Sang-Hyeok;Lee, Yong-Sam
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.1
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    • pp.52.2-52.2
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    • 2012
  • 1438년 장영실은 경복궁 흠경각(欽敬閣) 내부에 자동물시계인 옥루(玉漏)를 제작하였다. 흠경각루(欽敬閣漏)는 수격식(水激式, 물의 흐름을 이용하여 수차를 운행하는 동력방식)으로 운영되는 것으로 중국의 수운의상대(水運儀象臺, 1092년경 제작)의 수격방식과 유사하다. 하지만 동력 방식을 제외한 내부 구조에 대한 것은 흠경각루의 외형모습인 가산 형태, 시보인형의 구성과 배치, 작동구조 등에 의해 결정된다. 장영실은 흠경각루의 내부 기어장치의 구성과 연결 등에 대해서 새로운 제작기술을 사용하였다. 우리는 수격식 동력 방식에서 내부 공간에 따른 각각 운행 장치들의 구성과 동력전달체계에 대하여 분석하였다. 또한 수차가 일정한 회전력을 갖도록 제어하는 천형(天衡) 장치에 대하여 고찰하였다.

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