• Title/Summary/Keyword: Cho Ji-hoon

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Cost competitive Pixel Structures for Mobile PVA LCDs

  • Cho, Seon-Ah;Lyu, Jae-Jin;Sohn, Ji-Won;Park, Jin-Won;Park, Seung-Beom;Yang, Sung-Hoon;Jung, Mee-Hye;Kim, Kyeong-hyeon;Kim, Sang-Soo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08b
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    • pp.1639-1641
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    • 2007
  • We have designed cost competitive pixel structures for high performance mobile PVA LCDs. These new structures significantly bring down the price by the use of a conventional polarizer for lowest possible cost. A 4.3" prototype based on these techniques was built, achieving the world's highest mobile display contrast ratio of 1200:1, while maintaining wide viewing angle with no loss of transmittance

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Improved Method of Maximum Loadability Estimation in Power Systems By Transforming the Distorted P-e Curve (왜곡된 P-e곡선의 변환에 의한 전력계통 최대허용부하의 향상된 추정 방법)

  • Hwang, Ji-Hwan;Choi, Byoung-Kon;Cho, Byoung-Hoon;Moon, Young-Hyun
    • Proceedings of the KIEE Conference
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    • 2000.07a
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    • pp.363-365
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    • 2000
  • This paper presents an improved method to estimate the maximum load level for heavily loaded power systems with the load-generation variation vector by using the elliptic pattern of the P-e curve. The previous study suggested a simple technique of removing e-f coupling, where only high voltage load flow solutions to calculate transforming angle of system reference is needed. The proposed algorithm is improved to require only one load flow solution at a specific load level in addition to the operating point at the beginning stage, which reduces the computation time and the iteration number of estimation. The proposed method can be efficiently applied to heaviIy loaded systems with the combination of CPFlow when the reactive power limit and ULTC are considered. In this paper, the effect of ULTC on the estimation of maximum loadability index is also investigated. The proposed algorithm is tested on New England 39 bus system and IEEE 118 bus system.

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An Investigation on the Failure Examples of Space Launcher development in U.S.A./Europe (미국/유럽의 우주발사체 개발 중 실패사례 분석)

  • Kim, Ji-Hoon;Lee, Han-Ju;Jung, Dong-Ho;Cho, Sang-Yeon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2006.11a
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    • pp.93-98
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    • 2006
  • The advanced countries like the United States of America and Europe have experienced many failures in development of space launch systems. Research and analysis of the failures will be helpful to our launch system development. In this report, the failures of Space Shuttle in U.S.A. and Ariane in Europe were investigated and analyzed. These are excessively small portion of the failures, so it is necessary to investigate and research the more various failures of the other countries specially Russia(former Soviet Union).

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Oxygen contents monitoring in the building for launch and test facilities (발사대 및 시험장 건물 내의 산소농도 관리)

  • Kim, Ji-Hoon;Yoo, Byung-Il;Cho, Sang-Yeon;Kang, Sun-Il;Oh, Seung-Hyub
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.11a
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    • pp.246-249
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    • 2009
  • Test and launch facilities which use oxygen as the propellant of a launch vehicle have hazards of fire and explosion by the leakage of oxygen. Also, the personnel operating the facilities, which use the high-pressured gases like nitrogen and helium in the closed room, is exposed to the hazard of death from suffocation. Consequently, we should keep out of the hazards and the accidents by monitoring the contents of oxygen in the air. The method and the system construction for monitoring oxygen contents in the air and the results from its application to Naro space center are described on this paper.

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Anti-inflammatory and radical scavenging properties of Verbena officinalis

  • Shim, Hwan-Ki;Kim, Seong-Yeol;Kim, Bo-Rim;Cho, Jae-Park;Park, Yae-Jeong;Ji, Won-Geun;Cha, Dong-Seok;Jeon, Hoon
    • Advances in Traditional Medicine
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    • v.10 no.4
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    • pp.310-318
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    • 2010
  • Verbena officinalis (Verbenaceae) has been used as herbal medicine or health supplement in both Western and Eastern countries for centuries. In the present study, we examined the anti-inflammatory and antioxidant activities of the methylene chloride fraction of V. officinalis (VMC). To elucidate the anti-inflammatory properties of VMC, we investigated the inhibition effects of nitric oxide production in interferon-gamma (IFN-$\gamma$) and lipopolysaccharide-stimulated mouse peritoneal macrophages. VMC suppressed nitric oxide production, inducible nitric oxide synthase and cyclooxygenase-2 expression dose-dependently without notable cytotoxicity. In various radical scavenging assays, VMC exhibited strong scavenging effect on DPPH radical, superoxide radical, nitric oxide radical and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) radical. VMC also showed potent reducing power. These findings strongly suggest that VMC may be beneficial in oxidative stress-mediated inflammatory disorders.

Purification and Structural Characterization of Glycolipid Biosurfactants from Pseudomonas aeruginoas YPJ-80

  • Park, Oh-Jin;Lee, Young-Eun;Cho, Joong-Hoon;Shin, Hyun-Jae;Yoon, Byung-Dae;Yang, Ji-Won
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.3 no.2
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    • pp.61-66
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    • 1998
  • Glycolipids produced by Pseudomonas aeruginosa YPJ-80 were characterized by chromatographic and spectorscopic techniques as a mixture of two rhamnolipids. For recovery of glycolipids from the culture broth, various isolation methods including ultrafiltration, adsorption and solvent extraction were compared. Ultrafiltration showed the best results in terms of glycolipids recovery. Further purification for spectroscopic analysis was carried out by adsorption chromatography and preparative thin layer chromatography. From the spectroscopic analysis, such as IR spectroscopy. FAB-MS, 1H-NMR and 13C-NMR and hydrolysis analysis, the glycolipids were identified as L-${\alpha}$-rhamnopyranosyl-${\beta}$-hydroxydecanoly-${\beta}$-hydroxydecanoate and 2-O-${\alpha}$-L-rhamnopyranosyl-${\alpha}$-L-rhamnopyranosyl-${\beta}$-hydroxydecanoyl-${\beta}$-hydroxydecanoate. Monorhamnolipid and dirhamnolipid lowered the surface tension of water to 28.1 mN/M and 29.3 mN/m, respectively.

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A Study on design of The Internet-based scoring system for constructed responses (서답형 문항의 인터넷 기반 채점시스템 설계 연구)

  • Cho, Ji-Min;Kim, Kyung-Hoon
    • The Journal of Korean Association of Computer Education
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    • v.10 no.2
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    • pp.89-100
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    • 2007
  • Scoring the constructed responses in large-scale assessments needs great efforts and time to reduce the various types of error in Paper-based training and scoring. For the purpose of eliminating the complexities and problems in Paper and pencil based training and scoring, many of countries including U.S.A and England already have applied online scoring system. There, however, has been few studies to develop the scoring system for the constructed responses items in Korea. The purpose of this study is to develop the basic design of the Internet-based scoring system for the constructed responses. This study suggested the algorithms for assigning scorers to constructed responses, employing methods for monitoring reliability, etc. This system can ensure reliable, quick scoring such as monitor scorer consistency through ongoing reliability checks and assess the quality of scorer decision making through frequent various checking procedures.

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A study for interactive teacup using vision recognition system (비전 인식 시스템을 이용한 인터랙티브 찻잔 연구)

  • Cho, Hyun-Chul;Kim, Sung-Hyun;Kang, Ki-Ho;Lee, Ki-Hoon;Pan, Young-Hwan;Jung, Ji-Hong
    • 한국HCI학회:학술대회논문집
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    • 2008.02b
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    • pp.13-17
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    • 2008
  • By the change of the times and higher living standards, modern people are becoming interested in life value and culture. On this, in consideration of researches in behavior of people use teacup and drink tea; I develop a concept of interactive teacup which provides music of proper mood for people who drink and enjoy a cup of tea. The concept teacup is produced by adopting the ceramic craft process.

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50nm thick as-deposited poly silicon as an active layer of TFT for driving AM-OLEDs prepared at low temperature $(<200^{\circ}C)$ using Cat-CVD

  • Cho, Chul-Lae;Lee, Sung-Hyun;Lee, Chang-Hoon;Lee, Dea-Hyun;Lee, Sang-Yoon;Kwon, Jang-Yeon;Park, Kyung-Bae;Kim, Jong-Man;Jung, Ji-Sim;Hong, Wan-Shick
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.495-498
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    • 2006
  • The influence of various process parameters for the as-deposited poly silicon was investigated. The polycrystalline silicon films were successfully deposited on glass substrates at a low-temperature $(<200^{\circ}C)$ using the catalytic chemical vapor deposition (Cat-CVD). We achieved a low hydrogen content $({\sim}0.9%)$ and a high deposition rate $({\sim}35{\AA}/sec)$. The film is applicable to thin film transistors on plastic substrates.

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