• Title/Summary/Keyword: 이영식

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Flow-based Internet Traffic Measurement and Analysis (플로우 기반 인터넷 트래픽 측정 및 분석)

  • 이영식;옥도민;최양희;신효정;진영민
    • Proceedings of the Korean Information Science Society Conference
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    • 1998.10a
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    • pp.515-517
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    • 1998
  • 인터넷 급속도로 사용자, 트래픽, 호스트, 네트워크 등이 증가하고 있다. 이러한 증가에 따라 인터넷의 효과적인 관리를 위해서는 기본적인 인터넷 사용 트래픽의 측정 및 분석이 필요하다. 최근의 OC3mon, NetFlow System등의 트래픽 측정도구들은 고속의 인터넷 백본에서 유통되는 트랙픽들의 특성을 파악할 수 있도록 한다. 특히, 고속 인터넷 플로우 스위칭이 이용하는 IP패킷들의 연속적인 흐름인 플로운(flow)를 바탕으로 인터넷 트래픽 특성을 파악 할 수 있도록 한다. 본 논문에서는 플로우 기반의 인터넷 트래픽 측정도구 Cisco 라우터의 NetFlow 인터페이스와 Cflowd 수집기를 사용하여 국내 교육 인터넷 망의 트래픽을 측정하여 분석한 국내 인터넷 트래픽 특성 결과를 제시한다.

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Does the Long-Run Relationship of the Movement of Exchange Rate, Interest Rate, Stock Price (환율(換率).금리(金利).주가(株價) 변동(變動)의 장기균형관계(長期均衡關係)는 성립(成立)하는가?)

  • Lee, Young-Shik
    • International Commerce and Information Review
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    • v.3 no.1
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    • pp.277-294
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    • 2001
  • 본 연구는 환율과 금리 및 주가간의 균형관계를 나타내는 분석모형(分析模型)을 구축 제시하고, 그 분석모형을 구성하고 있는 일별(日別) 국내 외 금융지표의 변동간에 장기관계(長期關係)가 성립하는지 즉, 공적분(共積分) 관계(關係)의 성립여부를 분석하며, 이들 금융지표간 균형관계에 대한 안정성(安定性)(stationary) 여부를 검증함으로써 제시한 분석모형의 유효성(有效性) 즉, 장기모형관계(長斯模型關係)에 대한 성립여부를 분석하는 데 중점을 두고 있다. 분석결과는 분석모형의 변수간 장기관계 즉, 공적분 관계가 존재한다 할지라도 다변량 가설검증에 의하여 분석모형이 장기모형관계(長斯模型關係)로부터 유의적(有意的)으로 이탈할 수도 있다는 사실을 확충하고 있다.

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Design of High Efficient Gate Drive Circuit for IGBT (효율적인 IGBT 게이트 드라이브 회로에 관한 연구)

  • Lee, Young-Sik;Kang, Jun-Mo;Kim, Duk-Joong;Beak, Soo-Hyun;Kim, Yong
    • Proceedings of the KIEE Conference
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    • 1997.07f
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    • pp.2213-2216
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    • 1997
  • Efficient Switching of IGBT's requires fast gate drivers with high peak currents. This Paper will review the requirements for effient, reliable gate drive of IGBT's and behaviour of an IGBT switching chacteristcs. The purpose of the present paper is to investigate the switching loss mechanisms in IGBT such as MOSFETs in order to give a support to designers of IGBT gate drive circuits in selecting the more appropriate IGBTs to be used on the basics of design repuirements.

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A Study on the characteristics and Development of Power supply for ozonizer (오존 발생기용 전원 장치 개발 및 특성에 관한 연구)

  • Kim, Jong-Hae;Bae, Sang-June;Lee, Young-Sik;Jo, Gee-Yeun;Jeong, Seung-Kyun;Lee, Bong-Seop
    • Proceedings of the KIEE Conference
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    • 1997.07f
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    • pp.2069-2071
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    • 1997
  • The power semiconductor switching devices(PSSD) continuously developed, Power Electronic Technology using PSSD is gradually extended. The high frequency inverter to generate the large power high frequency subject to power electronic technology pursuit various application. Also, in emboss with environmental destruction problem cause the atmosphere and the water pollution to growth of the commercial society, the research in favor of cleansing environmental a pollutant actively proceed. This paper describe study on the ozone generation power supply using the high frequency electric field method and the lamp type ozone generator using photochemistry, one of method of gene-rate ozone.

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The Effect of Drill Helix Angle, Point angle, and Cutting Conditions on the Drilling Performance (드릴의 선단각, 나선각 및 가공조건이 가공성에 미치는 영향)

  • 이영식
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.6 no.4
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    • pp.138-146
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    • 1997
  • The optimal drill helix angle, point angle, and cutting conditions are recommended in the study so as to maximize the drilling performance by investigating the experimental reaults concerning with the state of chip formation, roundness of machined holes, and geometry of projected burr at hole exit, which are examined under the conditions of various helix angles, drill point angles of twist drill, cutting speeds, and feeds in operional parameters. In the easiness of chip escape, the helical type of chip is producted when a helix angle is 30$^{\circ}$, drill point angle 118$^{\circ}$, 140$^{\circ}$and feed is st between 0.1 and 0.15mm/rev. Roundness of machined hole is improved when the helix angle is 37$^{\circ}$, drill point angle is 118$^{\circ}$, and feed is 0.15mm/rev. The height of projected burr at the button of machined hole increases when the drill point angle and helix angle becomes large.

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Calculation of induced currents and analysis of shielding effectiveness in finite conductive shield (도전성 유한 차폐판의 유도전류 계산 및 차폐효과 분석)

  • Kang, Dael-Ha;Son, Jung-Dae;Lee, Yung-Sik;Jo, Yeong-Ho;Choi, Phil-Soo;Park, Sang-Ho;Kim, Won-Hi
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.551-552
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    • 2011
  • In this study new evaluation method of eddy currents in conductive shielding sheets are introduced. This method is based on the magnetic flux linkage in rectangular cells. According to this method the allocated amount of memory and the calculation time can be reduced. In this method calculation of magnetic field in any space can be performed by summing contributions of source currents and eddy currents in conductive shielding sheets. This method is applicable to the design of magnetic field-shield.

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Reduction Effects of Electromagnetic fields in Conductor Shields (도체차폐판의 전자계 감소효과)

  • Kang, Dae-Ha;Kim, Won-Hee;Lee, Yuong-Sik;Son, Jung-Dae;Park, Yoon-Dong;Park, Sang-Ho
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.1595_1596
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    • 2009
  • In this study reduction effects of magnetic field were analyzed using multi-conductor method in analysis of shield. The method can be effective in the analysis because of reducing the amount of allocated memory and computing time. And also the method can be applicable to analysis of the induced current distributions and skin effect in shield. The results of the analysis are presented.

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Calculation and Mitigation of Elotromagnetic Fields for Indoor Distribution Lines (옥내배선의 전자계계산 및 감소대책)

  • Kang, Dae-Ha;Jo, Yong-Ho;Lee, Yuong-Sik;Park, Sang-Ho;Kim, Hui-Chil
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.1572_1573
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    • 2009
  • In this study electromagnetic fields generated by currents of electric wires with finite lengths were deduced and formulated to apply to the indoor distribution lines and also using the formula electromagnetic fields were calculated for various configurations of conductors and through analyzing the results mitigation of electromagnetic fields was investigated.

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Spillway Design by Using Numerical Model Experiment - Case Study of AnDong Multipurpose Dam - (수치모형실험을 이용한 여수로 설계 - 안동다목적댐 -)

  • Kim, Dae-Geun;Park, Sun-Jung;Lee, Young-Sik;Hwang, Jong-Hoon
    • Proceedings of the Korea Water Resources Association Conference
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    • 2008.05a
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    • pp.1604-1608
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    • 2008
  • 최근 기상이변 등에 따라 빈번히 발생하는 이상홍수에 대비하여 댐의 안정성 확보를 위한 댐설계기준이 강화되었고, 이에 따라 가능최대홍수량(PMF) 유입시 댐의 항구적인 안전성 확보를 위하여 치수능력 증대사업이 필요하게 되었다. 본 연구에서는 안동댐의 치수능력 증대사업의 일환으로 계획된 비상여수로에 대하여 2차원, 3차원 수치모형실험을 통해 비상여수로의 수리학적 안정성과 기능성을 검토하였다. 최적의 설계안을 결정하는데 필요한 자료를 제공하기 위하여 접근수로의 유황, 월류위어의 방류능력, 급경사수로 및 감세공의 유황을 검토하였다. 특히, 월류위어의 교각형상에 따른 수면형상, 조절부의 제원에 따른 방류량 검토, 조절부의 평면형상에 따른 유황, 급경사수로의 종단경사에 따른 유황, 저유량 방류시 플립버킷부에서의 사출궤적 등에 대한 검토 등을 수행하였다. 본 연구결과, 수치모형실험은 설계자에게 실용적인 해석도구로 사용될 수 있음을 보일 수 있었다.

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A Electronic Intergovernmental Relations(e-IGR) between the Central Government of Korea and the Seoul Metropolitan Government (고객관계관리 (CRM)의 주요성공요인과 성과간의 관련성 연구)

  • Go, Chang-Bae;Yun, Jong-Su;Lee, Yeong-Sik;Jo, Jae-Wan;Cha, Dae-Gyu
    • 한국디지털정책학회:학술대회논문집
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    • 2004.05a
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    • pp.369-382
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    • 2004
  • This study is to analyze the relationships between critical success factors of customer relationship management and performance of customer relationship management. To accomplish this purpose, this study performed an empirical analysis of 206 domestic companies which have introduced customer relationship management applications. The result of the study shows that most organizational factors except evaluation and compensation factor have a positively significant effect on the performance of customer relationship management, and that ease of system use and level of system integration influence on the performance of customer relationship management positively.

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