• Title/Summary/Keyword: Choi Chang Hak

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The application and Verification of the 2MVA BESS with Wind farm in Microgrid of Gapado.Jeju. (제주 가파도 마이크로그리드에서의 풍력발전 연계를 위한 2MVA급 BESS 적용 및 실증)

  • Kim, Seung-Mo;Oh, Seung-Jin;Lee, Jong-Hak;Ahn, Jae-Min;Jin, Kyung-Min;Kwon, Byung-Gi;Choi, Chang-Ho
    • Proceedings of the KIPE Conference
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    • 2013.11a
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    • pp.127-128
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    • 2013
  • 본 논문은 POSCO ICT가 개발한 2MVA/500kWh급 BESS(Battery Energy Storage System)의 가파도 마이크로그리드 적용사례와 실증결과에 대해 기술하였다. 이를 위해 가파도 마이크로그리드 구성과 BESS 역할을 설명하였고, 적용된 기술을 소개하였다. 또한 시험항목과 의의를 서술하고, 시험결과를 통해 계통망의 전력품질 및 BESS 제어성능을 검증하였다.

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TFT-LCD Employing RGBW Color

  • Lee, Baek-Woon;Song, Keun-Kyu;Yang, Young-Chol;Park, Cheol-Woo;Oh, Joon-Hak;Chai, Chong-Chul;Choi, Jeon-Gye;Roh, Nam-Seok;Hong, Mun-Pyo;Chung, Kyu-Ha;Lee, Seong-Deok;Kim, Chang-Yong
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.1103-1107
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    • 2004
  • Last year, we introduced a TFT-LCD with RGBW color system. The primary advantage of the RGBW system is that its optical efficiency is at least 50% higher than the RGB system. However, it is not a simple task to incorporate the new color system into the infrastructure of the RGB system: the driving circuitry, fabrication of color filter, and color conversion. In this report, the practical hurdles are discussed and the solutions are presented.

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Effects of Chemical Additives on Nitrogen Contents in Dairy Slurry (젖소 액상분뇨에 화학제재를 첨가 시 질소 함량에 미치는 영향)

  • Choi, In-Hak;Kim, Chang-Mann
    • Journal of Environmental Science International
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    • v.18 no.7
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    • pp.811-817
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    • 2009
  • To determine changes in nitrogen contents and optimal rates as N fertilizer, we investigated nitrogen characteristics in the slurry in the respond to the application of 0, 0.5, and 1 g of ferrous sulfate or alum /25g of dairy slurry. Additions of ferrous sulfate or alum increase total nitrogen, inorganic nitrogen, available nitrogen, and predicted available nitrogen contents in dairy slurry, resulting in reduction in pH. The best results were found in the treatment with 0.5 g of ferrous sulfate or alum /25 g of dairy slurry. In conclusion, the use of ferrous sulfate or alum as on-farm amendment to dairy slurry should be represented an alternative to improve N in dairy slurry.

A Study on the Heat Dissipation of LED Streetlight Using PCM (PCM을 이용한 LED 가로등의 방열에 관한 연구)

  • Jung, Eui-Chan;Chang, Sung-Ho;Kang, Seoug-Wan;Kim, Min-Ho;Nho, Kwon-Hak;Lee, Young-Wook;Choi, Yu-Bok
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.33 no.4
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    • pp.79-84
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    • 2010
  • In recent years, conventional streetlight is replaced by LED streetlight to reduce power consumption dramatically and to maximize lighting effects. However the characteristic of power LED itself driven by high current to increase the illumination, we need to develop effective heat release device. This study suggests new concept of heat dissipation device using PCM (Phase Change Material) and shows an experiment results to investigate thermal effects of PCM.

Development of a Synchronous Web-Collaboration System (실시간 웹 협력 시스템 개발)

  • Kim, Il-Joong;Kim, Ji-Yong;Jung, Yong-Moon;Lee, Chang-Seok;Choi, Hong-Keun;Lee, Sung-Gu;Joe, Hak-Rae
    • Proceedings of the Korea Information Processing Society Conference
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    • 2001.10b
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    • pp.1205-1208
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    • 2001
  • 인터넷의 보급과 발전으로 그 동안 지리적인 한계로 인해 불가능했던 협력작업이 인터넷 가상공간에서 가능하게 되었다. 그 동안 이메일, 전자게시판, FTP와 같은 정적인 형태의 협력작업에 관한 연구에서 웹을 이용한 동적인 협력작업에 관한 연구가 진행되어 왔다. 최근에는 웹을 이용한 다양한 협력 기능이 요구되면서 공동 브라우징 (Co-browsing)과 같은 단순한 웹 협력이상의 다양한 협력작업을 만족시킬 수 있는 실시간 웹 협력 (Synchronous Web-Collaboration) 시스템 연구가 진행되고 있다. 본 논문에서는 실시간 웹 협력 시스템 구축에 필요한 시스템 구성요소와 설계 방법을 소개하고 비즈니스 특성을 고려한 실시간 웹 협력 시스템 구축 모델을 제시한다.

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Remote Multi-Communication System for Networking of LED Lighting Devices (LED 조명장치의 네트워킹을 위한 원격다중통신시스템)

  • Li, Lin-Rong;Chang, Young-Hak;Lee, Jin;Ryoo, Young-Jae;Choi, Moon-Ho;Kwak, Jae-Young
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.1779_1781
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    • 2009
  • The main contents of this paper is to design a system that can remote control the most of the LED lighting device in the market. In order to realize the device driver, we choose the communication mode Zigbee, PLC, RS232 and RS485. Using client-server system, LED lighting device can be controlled just through web browser.

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Improvement of the Sustain-driving Characteristics of AC PDP by Changing the Position of the Inductor

  • Choi, Jeong-Pil;Park, Sang-Hyun;Jung, Woo-Chang;Cho, Kyu-Choon;Moon, Seong-Hak
    • Journal of Information Display
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    • v.9 no.4
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    • pp.45-49
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    • 2008
  • The characteristics of the sustain-driving circuit were examined in this paper. The sustain-driving circuit is in charge of the most important part of PDP driving because it manages most of the power consumption in the PDP. A couple of gatedriving circuits for the sustain-driving circuit were introduced in this paper, and a new driving circuit was also proposed. This new circuit is more cost-effective and has a simpler PCB layout compared to the conventional one. Some additional driving advantages were noted as well.

A Study on Gamma Dose Rate in Seoul(I) (서울시내 공간 감마선량률 조사(I))

  • Kim, You-Hyun;Kim, Chang-Kyun;Choi, Jong-Hak;Kim, Jeong-Min
    • Journal of radiological science and technology
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    • v.24 no.1
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    • pp.61-65
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    • 2001
  • This study was conducted to find out gamma dose rate in Seoul, from January to December in 2000, and the following results were achieved ; 1. The annual gamma dose rate in Seoul was $17.24{\mu}R/hr$ as average. 2. The annual gamma dose rate in subway of Seoul was $14.96{\mu}R/hr$ as average. 3. The highest annual gamma dose rate was Dong-daemon ku. 4. Annual gamma dose rate in Seoul was higher autumn than winter.

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Diskospondylitis with Pyometra in a Dog

  • Kim, Hak-Sang;Lee, Jung-Min;Kim, Gyeong-Min;Lee, Sung-Ok;Oh, Sun-Kyung;Chang, Jin-Hwa;Jung, Joo-Hyun;Choi, Min-Cheol;Yoon, Jung-Hee
    • Proceedings of the Korean Society of Veterinary Clinics Conference
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    • 2006.05a
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    • pp.187-187
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    • 2006
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Noise Removal for Improvement of Occupancy-grid Map

  • Kim, Young-Geun;Choi, Chang-Min;Kim, Hak-Il
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.138.4-138
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    • 2001
  • The purpose of this research is to build a quality-improved occupancy grid map for path-planning of an autonomous mobile robot(AMR) based on the measurements from a single ultrasonic sensor, which are acquired when the autonomous mobile robot explores unknown indoor environment. The AMR navigates in the unknown space by following the wall and gathers the range data using the ultrasonic sensor, from which the occupancy grid map is constructed by associating the range data with occupancy certainties. In order to increase the quality of the map we modify the Bayesian probability updating rule, reject non-systematic measurement errors and correct the predictable error of the AMR itself. These procedures are implemented and tested using an AMR, and primary results are presented in this paper.

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