• Title/Summary/Keyword: Gyu-Dong Choi

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The Displacement Minimization of the tool Center Point by the Crossrail Structure Improvement of the Portal Machine (공구 중심점의 변위 최소화를 위한 문형 공작기계의 크로스레일 개선 연구)

  • Lee, Myung-Gyu;Song, Ki-Hyeong;Choi, Hag-Bong;Lee, Dong-Yoon
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.20 no.3
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    • pp.310-315
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    • 2011
  • General portal machine represents a distinct weak spot concerning their structural behavior because of long protruding structure components, such as saddles and rams. The weak point causes the deformation of the machine tool and consequently rises a severe machining error. The purpose of this study is to improve the structural design of crossrail in order to minimize it's distortion. Tool Center Point (TCP) was chosen as a reference point for evaluating the distortion effect of a crossrail and topological optimization was adopted as a method of structural design improvement. The displacements of TCP according to the machining positions were investigated by structural analyses for both of original crossrail design and the improved one. The comparing results showed that the displacement of TCP could be reduced about 55% maximum.

Implementation and Application of the Control Surface Deflection Angle measuring device for UAV using Potentiometer (전위차계를 이용한 무인항공기 조종면 변위 측정 장치 구현 및 적용)

  • Kim, Ji-Chul;Choi, Il-Gyu;Gong, Sung-Chul;Cheon, Dong-Ik;Lee, Sangchul;Oh, Hwa-Suk;Kang, Min-young
    • Journal of Aerospace System Engineering
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    • v.3 no.3
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    • pp.13-16
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    • 2009
  • Aircraft flight control surfaces which are one of the most important elements of safety allow a pilot to adjust and control the aircraft's flight attitude. This paper is described of the control surface deflection angle measuring device. Data analysis through ground test and flight test can provide reliability of this device using the present system. It is also shown that measuring system is capable of detecting failure of control surfaces.

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Development of GIS-based Advertizing Postal System Using Temporal and Spatial Mining Techniques (시간 및 공간마이닝 기술을 이용한 GIS기반의 홍보우편 시스템 개발)

  • Lee, Heon-Gyu;Na, Dong-Gil;Choi, Yong-Hoon;Jung, Hoon;Park, Jong-Heung
    • Spatial Information Research
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    • v.19 no.2
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    • pp.65-70
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    • 2011
  • Advertizing postal system combined with GIS and temporal/spatial mining techniques has been developed to activate advertizing service and conduct marketing campaign efficiently. In order to select customers accurately, this system provide purchase propensity information using sequential, cyclicpatterns and lifesytle information through RFM analysis and clustering technique. It is possible for corporate mailer to do customer oriented marketing campaign with the advertizing postal system as well as 'one-stop' service including target customer selection, mail production, and delivery request.

A Study on the Optimal Acceleration Profile to Reduce Vibration of PMLSM (PMLSM의 진동저감을 위한 최적의 속도 궤적 생성에 관한 연구)

  • Lee Dong-Yeup;Kim Gyu-Tak;Choi Young-Hyu
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.54 no.8
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    • pp.351-357
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    • 2005
  • This paper presents vibration minimization of a PMLSM driven feed-slide by using optimized smooth velocity curve with finite jerk. First of all, the PMLSM was designed and made to reduce detent force. Next, a PMLSM driven feed-slide system was mathematically modeled as a 4-degree-of-freedom lumped parameter model. The key idea of our vibration minimization method is to find out the most appropriate smooth velocity(feedrate) curve with finite jerk. The validity of our proposed method has been verified by comparing computer simulation results of the feed-slide model with experimental ones.

5kVA 3-level PFC Converter in Thermal Analysis : Comparison of Simulation and Experiment (5kVA 3레벨 PFC 컨버터의 열해석 모의 및 실험적 비교)

  • Lee, Do-Hong;Han, Yu;Choi, Dong-Min;Cho, Younghoon;Choe, Gyu-Ha
    • Proceedings of the KIPE Conference
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    • 2017.07a
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    • pp.359-360
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    • 2017
  • This paper presents comparison of simulation and experiment in thermal analysis of 3-level PFC. Thermal analysis is necessary to optimize the power conversion system to get higher efficiency. Accordingly, analysis via simulation tools and analytic methods is performed to predict the power losses of converter. Consequently, thermal results of 3-level PFC experiment is compared with thermal analysis.

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A Study on the Algorithm Design of CES_RTU(Consumer Electrical Safety-Remote Terminal Unit) using Telemetrics Method (텔레메트릭스 기법을 적용한 옥내용 전기안전감시시스템(CES_RTU)의 알고리즘 설계에 관한 연구)

  • Kim, Young-Sik;Kwon, Wan-Sung;Han, Dong-Hwa;Choi, Jung-Muk;Yoo, Jae-Geun;Choe, Myeong-Il;Choe, Gyu-Ha
    • Proceedings of the KIPE Conference
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    • 2008.10a
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    • pp.157-159
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    • 2008
  • 본 논문은 전력의 안정적 공급 및 신뢰도 확보를 위해 전력설비의 실시간 감시 및 예방진단 시스템을 위해 텔레메트릭스 기법을 이용한 원격 통신시스템에 대한 연구를 통한 옥내용 전기안전감시진단시스템 (CES_RTU : Consumer Electrical Safety-Remote Terminal Unit)에 대한 새로운 알고리즘을 설계에 관련된 연구를 하였다.

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Interoperating Methods of Heterogeneous Networks for Personal Robot System (퍼스널 로봇을 위한 이기종 네트웍 운용 방안)

  • Choo, Seong-Ho;Li, Vitaly;Lee, Jung-Bae;Park, Tai-Kyu;Jang, Ik-Gyu;Jung, Ki-Deok;Choi, Dong-Hee;Park, Hong-Seong
    • Proceedings of the KIEE Conference
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    • 2004.05a
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    • pp.86-88
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    • 2004
  • Personal Robot System in developing, have a module architecture, each module are connected through variety network system like ethernet, WLAN (802.11), IEEE 1394 (firewire), bluetooth, CAN, or RS-232C. In developing personal robot system. We think that the key of robot performance is interoperablity among modules. Each network protocol are well connected in the view of network system for the interoperability. So we make a bridging architecture that can routing converting, and transporting packets with matching each network's properties. Furthermore, we suggest a advanced design scheme for realtime / non-realtime and control signal (short, requiring hard-realtime) / multimedia data (large, requiring soft-realtime).

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Carbon Fiber Surface treatment for high density of CNT (높은 밀도의 CNT on CF 합성을 위한 CF 표면처리공정)

  • Choi, Kang-Ho;Sim, Won-Hyeon;Lee, Hui-Su;Im, Dong-Chan;Jeong, Yong-Su;Lee, Gyu-Hwan
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2009.10a
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    • pp.181-181
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    • 2009
  • 탄소섬유의 우수한 기계적, 화학적, 전기적 특성을 이용한 산업전반에 대한 연구가 활발히 수행되어 지고 있다. 본 연구에서는 탄소섬유를 supercapacitor의 전극과 복합체에 활용하기 위해서 탄소섬유상에 탄소나노튜브를 증착시키는 실험을 수행하였다. 균일하고 높은 증착 밀도의 탄소나노튜브를 증착시키기 위해서 본 연구에서는 기존의 CF 표면처리 방법- anodizing, plasma treatment, heat treatment등과 달리 간단한 wet-process방법을 이용해 CF 표면처리 및 catalyst증착공정을 동시에 수행하여 고밀도의 CNT를 증착하였다.

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An Architectural Design for Scalable Web based Real-time Video Streaming Platform (확장성 높은 웹 기반 실시간 비디오 스트리밍을 위한 플랫폼 구조 설계)

  • Yoon, Dong-Sik;Kim, Seong-Hwan;Choi, Gyu-beom;Youn, Chan-Hyun
    • Proceedings of the Korea Information Processing Society Conference
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    • 2015.04a
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    • pp.150-152
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    • 2015
  • Web Real-Time Communication(WebRTC) 기술은 웹 기반으로 실시간 스트리밍 서비스를 제공하기 위해 쓰이는 기술이다. WebRTC 기술은 인터넷 상의 두 컴퓨팅 노드 사이의 Peer-to-Peer RTP 연결을 가능케 함으로써 상호간 실시간 스트리밍을 가능케 하지만 컨퍼런스 시스템과 같이 다수의 노드가 통신에 참여하는 경우 네트워크 연결은 메쉬 토폴로지의 형태로 구성되어 대역폭의 한계로 확장성에 제한이 존재한다. 따라서 본 논문에서는 인코딩과 먹싱을 통해 다중 노드간의 통신을 중계를 지원하는 Multipoint Control Unit(MCU)과 MCU 사이의 클러스터링, 그리고 클라우드 플랫폼을 통해 확장성 높은 실시간 스트리밍 서비스를 지원하는 플랫폼 구조를 설계하고 그 예제를 보인다.

Discharge Coefficient Characteristics in Hot-firing Tests of a Subscale Gas Generator (축소형 가스발생기 연소시험에서의 유량계수 특성)

  • Kim, Mun-Ki;Lim, Byoung-Jik;Kang, Dong-Hyuk;Ahn, Kyu-Bok;Kim, Jong-Gyu;Choi, Hwan-Seok
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.04a
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    • pp.73-76
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    • 2011
  • The hot-firing tests of a subscale gas generator were successfully performed to investigate the effect of injector shape variation on discharge coefficients. The test results showed that discharge coefficients of fuel and liquid oxygen injectors remained nearly constant irrespective of variations of a mixture ratio and a chamber pressure. Especially, the discharge coefficient of the liquid oxygen injector was largely increased compared to the previous works.

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