• Title/Summary/Keyword: Chun-Kwang

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A Parallel Coupled QVCO and Differential Injection-Locked Frequency Divider in 0.13 μm CMOS

  • Park, Bong-Hyuk;Lee, Kwang-Chun
    • Journal of electromagnetic engineering and science
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    • v.10 no.1
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    • pp.35-38
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    • 2010
  • A fully integrated parallel-coupled 6-GHz quadrature voltage-controlled oscillator (QVCO) has been designed. The symmetrical parallel-coupled quadrature VCO is implemented using 0.13-${\mu}m$ CMOS process. The measured phase noise is -101.05 dBc/Hz at an offset frequency of 1 MHz. The tuning range of 710 MHz is achieved with a control voltage ranging from 0.3 to 1.4 V. The average output phase error is about $1.26^{\circ}$ including cables and connectors. The QVCO dissipates 10 mA including buffer from the 1.5 V supply voltage. The output characteristic of the differential injection-locked frequency divider (DILFD), which has similar topology to the QVCO, is presented.

The Extended Design & Implementation of DLInfra for supporting External Service in the Digital Library (디지털도서관에서 외부서비스 지원을 위한 DLInfra확장 설계 및 구현)

  • Lee, Kwang-Hee;An, Gae-Il;Chun, Woo-Jik
    • Proceedings of the Korean Information Science Society Conference
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    • 1998.10a
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    • pp.430-432
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    • 1998
  • 디지털도서관은 디지털로 표현된 음성, 화상, 문서 등 다양한 유형의 정보들이 통신망을 통하여 손쉽게 전급하고 원하는 형태로 표현할 수 있는 새로운 개념의 도서관이다. 우리는 분산 환경에서 도서관 모델을 연구해 왔고 디지털도서관 내부에 분산되어 저장된 데이터(내부데이터)를 검색하고 이용할 수 있는 DLInfra를 구현했다. 본 논문에서는 기존 DLInfra 구조의 수정 없이 외부서비스 제공자가 제공하는 외부데이터를 관리 및 검색할 수 있는 확장된 구조를 제안한다. 이를 위하여 외부 데이터를 검색 및 등록하기 위하여 프로토콜 게이트웨이와 외부데이터 등록 에이전트 설계 및 구현하였다.

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Design of an Ultra-Compact UHF Passive RFID Tag Antenna for a Medical Sample Tube

  • Lee, Jung-Nam;Hwang, Moon-Young;Lee, Sang-Il;Lee, Kwang-Chun;Park, Jong-Kweon
    • ETRI Journal
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    • v.34 no.6
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    • pp.974-977
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    • 2012
  • In this letter, a small-sized ultra-high frequency (UHF) RFID tag antenna for a medical sample tube is proposed. The RFID tag antenna is designed and fabricated based on the circular loop antenna used in the UHF band (Korea standard, 917 MHz to 923.5 MHz). The tag antenna size is reduced using a circular meander stub. The antenna has a physical size of 8 mm, which is about ${\lambda}$/40 in electrical length. The proposed tag antenna is molded into a medical sample and multitag identification is performed.

Pharmacological Effects and Medicinal Components of Korean Ginseng (Panax ginseng C. A. Meyer) (고려인삼의 약리효능과 효능성분)

  • Choi, Kwang-Tae;Yang, Deok-Chun
    • The Korean Ginseng Research and Industry
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    • v.6 no.2
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    • pp.2-21
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    • 2012
  • 현대과학에 의하여 밝혀진 고려인삼의 약리효능을 보면 뇌 기능 개선, 통증감소, 암 예방 및 항암작용, 면역기능 항진, 간 기능 개선, 항당뇨, 혈압 조절기능, 항피로, 항 스트레스, 여성 갱년기장애 개선, 남성 발기부전 개선, 항 산화, 항 노화 등에 관한 효능을 들 수가 있으며, 고려인삼의 효능성분으로서는 ginsenosides(인삼사포닌), 페놀화합물, 폴리아세틸렌화합물, 다당체 특히 산성다당체, 펩타이드 등이 주류를 이루고 있다. 효능성분 중에는 특히 ginsenosides에 관한 연구가 많이 수행되었는 바, 고려인삼이 타국삼에 비하여 다양한 종류의 ginsenosides가 함유되어 있다는 것이 판명되었다.

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Cognitive and Conduct Disorder Rehabilitation Systems using CAMSHIFT Algorithm (CAMSHIFT를 활용한 실시간 인지 및 행동 장애 재활 시스템)

  • Chun, Sung-Min;Whoang, In-Teck;Kim, Don-Kyu;Choi, Kwang-Nam
    • 한국HCI학회:학술대회논문집
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    • 2006.02a
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    • pp.103-109
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    • 2006
  • 본 논문은 인지 및 행동 장애 재활 시스템을 구현하기 위하여 동영상인식 기반의CAMSHIFT 알고리즘을 적용시켰다. 주의력과 반응 시간을 측정하는 인지 장애 재활 시스템이 개발되었고 환자의 주의 집중력과 손 움직임의 조절력을 측정하고 시 지각 운동 능력을 측정하는 행동 장애 재활 시스템이 개발되었다. 실험은 중앙대학교 의료원 재활 의학과에서 실시하여 측정되었다. 본 논문에서 개발한 시스템은 훈련 과정을 객관적인 측정량과 오랫동안 연습할 수 있는 동기를 제공해 줌으로써 전통적인 치료법에 비해 흥미롭고 유용한 도구가 될 수 있음을 환자를 치료하는 치료사를 대상으로 PSS CogRehab 시스템과 비교하는 설문 조사를 통하여 증명한다.

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A Study on e-Commerce Performance in China's SMEs at Jilin Province (중국 길림성 중소기업의 전자상거래 성과에 관한 연구)

  • Yun, Kwang-Woon;Lee, Chun-Su;Li, Ben-Ke
    • International Commerce and Information Review
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    • v.11 no.4
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    • pp.3-23
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    • 2009
  • Social surveys, using various factors influencing the e-commerce's development of SMEs, are the means of explaining the rapid development of e-commerce. This makes it possible to make more efficient decisions in e-commerce. This article was written from surveys conducted in the manufacturing industry and Trade Company at Jilin Province via e-mail, fax and analyzed data by Statistical Package for the Social Sciences (SPSS). The result shows that in development of e-commerce, the business partners have significant impacts on the achievement of e-business both directly and indirectly. Second, consciousness of leaders, external support, transaction partner relationship and influence of competitors cause a direct result on the development of e-commerce On the other hand, the innovative capacity of enterprises and communication indirectly influence. Based on these, it is valid for us to for us to make correct decisions for the e-commerce development of SMEs.

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Synthesis of Ketoconazole Derivatives

  • Ryu, Jae-Chun;Lee, Kwang-Jae;Lee, Sang-Hee
    • Bulletin of the Korean Chemical Society
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    • v.24 no.4
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    • pp.460-466
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    • 2003
  • For the drug master file (DMF) of ketoconazole, four impurities (1-4) contained in ketoconazole were synthesized. During the synthesis of 2, a new synthetic method of 1,4-dihydropyrazine was established. To oxidize the aminoalcohol (2j) to the aminal (2j-1), the standard Swern oxidation condition was modified to mask the nucleophilicity of the amino group temporarily using one equivalent of acetic acid. Derivative 3 was synthesized via regioselective bromination at the 2 position of the 4-aminophenol derivative (3a) using $Br_2$ in the presence of p-TsOH. The etherification of aryl bromide with the phenol derivative (1f) was accomplished by a modification of the general Cu-mediated reaction condition using excess 1f itself as a solvent at elevated temperature (190 ℃).

Numerical Simmulation of Carbon Dioxide Compressible Fluid Flow and Heat Transfer under Supercritical State in a Straight Duct with Square Cross Section (초임계 상태 이산화탄소의 정사각 직덕트 내 압축성 유동 크기 열전달의 전산해석)

  • Joo, Kwang-Sup;Choi, Young-Don;Chun, Kun-Ho;Kim, Dong-Chul;Bae, Doo-Ho
    • Proceedings of the KSME Conference
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    • 2001.06e
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    • pp.524-529
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    • 2001
  • Because of the ozone layer depletion and global wanning, new alternative refrigerants are being developed. Among them, HFC refrigerants are thought promising, but some European countries are arguing that these refrigerants are also harmful to the global wanning. Therefore, natural refrigerants should be considered as an eventual alternative in refrigerators and heat pumps. In the present study, the supercritical gas cooling process are computationally analysed by employing various turbulence models of carbon dioxide in a trans critical refrigeration cycle. The gas cooling process near the critical point experiences a drastic change in thermodynamic and transport properties, thus the heat transfer characteristics would be different from those of two or single phases. Based on the computational results, the correlations to estimate the near-critical heat transfer characteristics will are obtained.

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Fabrication of high brightness multi-lamp backlight system for a large size LCD panel inspection equipment

  • Chun, Young-Tea;Lim, Sung-Kyoo;Lee, Kwang-Kyu;Lee, Hwan-Woong
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.787-790
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    • 2004
  • The large size and high brightness backlight system for LCD panel inspection equipment was designed, fabricated, and evaluated. The cold cathode fluorescent lamp (CCFL) instead of the hot cathode fluorescent lamp (HCFL) were used as the light source. The inverters for driving multi-lamp CCFL backlight systems were also designed and fabricated. The measured luminance of the fabricated CCFL backlight system was 20,000 cd/$m^2$ and the uniformity of the backlight was 85%. The fabricated backlight system was successfully applied to the LCD panel inspection equipment.

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