• Title/Summary/Keyword: Choi Buk

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PWM-VSI controller of Three-phase UPS Using Stationary Reference Frame (정지좌표계를 이용한 3상 UPS용 PWM-VSI 제어)

  • Kim M.K.;Kim J.S.;Bang S.S.;Choi J.H.
    • Proceedings of the KIPE Conference
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    • 2003.07b
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    • pp.965-968
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    • 2003
  • This paper describes the PWM-VSI controller of three-phase UPS system using stationary reference frame. This controller meets the specification the UPS inverter output voltage even under the unbalanced or nonlinear load. This controller is also constructed with duble control loop of the outer voltage control loop and the inner current control loop. For the fast response of the output voltage control, yhr inner current control loop of the capacitor current os used. To get the good property against overshoot, the If controller us used. The outer voltage controller is designed with P controller and the high gain transfer function is used for the zero steady state error. All control gains of both controller is designed base on the CDM method.

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Design of Grid Connected Photovoltaic System with Stand-alone Operation (독립운전기능을 갖는 계통연계형 태양광 발전시스템의 설계)

  • Kim M.S.;Lee S.H.;Hong J.S.;Choi J.H.
    • Proceedings of the KIPE Conference
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    • 2003.07b
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    • pp.969-972
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    • 2003
  • This paper deal with a necessary factors for design grid connected photovoltaic system with stand-alone operation, and show simulation results of individual functions and multi- operation according to utility condition. Generally, photovoltaic system have only one operation of either stand-alone or line interactive, and have a isolation transformer for electrical isolation from utility therefore it is bulky, weighty, and a high price system as compared with usefulness. In this paper, A topology and algorithm adequate for lightweight, high efficiency, low price, multi function is selected and inquired into the validity using simulation of variable conditions.

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A Study Markup Language using Design of DOM From (DOM형식 설계를 이용한 마크업 언어연구)

  • Lee, Don-Yang;Choi, Han-Yong
    • Proceedings of the Korea Information Processing Society Conference
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    • 2005.11a
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    • pp.341-344
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    • 2005
  • DOM은 기본적으로 XML 문서를 구조적으로 표현한 것이다. 그리고 DOM은 XML문서를 노드의 트리로 인식하며, 이 노드는 동작이 가능한 오브젝트들로 구성되었다. 여기서 각 엘리먼트는 노드이며, 이 노드는 서브트리를 구성할 수 있다. 본 논문에서는 DOM 트리생성을 이용한 XML 스키마의 생성 방법 중 기본적인 사용형태인 사용자 정의 심플타입 DOM 트리 설계의 모든 노드 요소들은 IXMLDOMElement의 형식으로 엘리먼트들을 정의하여 클래스내의 단위 엘리먼트의 속성여부와 모델 내의 클래스 관계를 표현할 수 있도록 하였다. 마크업언어의 생성에서는 XML 스키마를 이용하여 세부적인 데이터타입의 선언이 가능하도록 하고 있다.

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Development of Portable Electrical Ventilator (전기 구동 이동형 인공호흡기의 개발)

  • Ko, S.H.;Choi, N.B.;Kim, D.W.;Lee, S.H.;Lee, T.S.
    • Proceedings of the KOSOMBE Conference
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    • v.1997 no.11
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    • pp.105-108
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    • 1997
  • In this paper, we developed a portable electrical ventilator that could be controlled by the microcontroller. Control algorithm of motor drive t programmed with ASM96 assembly language software. We evaluated the system by measuring the parameters such as motor speed, feedback gain and overall specification.

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Evaluation of the Menus of Free Meal Service Centers for Home-bound Elderly (재가노인들을 위한 무료급식소의 식단 평가)

  • Han, Kyung-Hee;Park, Jung-Sook;Choi, Mee-Sook;Chung, Soon-Dool;Chai, In-Sook
    • Journal of the Korean Society of Food Culture
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    • v.17 no.5
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    • pp.584-593
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    • 2002
  • The purpose of this study was to evaluate the diet quality of the menus delivered by 17 free meal service centers for the low-income home-bound elderly in Chung- cheong buk-Do. Statistical data analysis was compleleted using the SPSS package program for descriptive analysis, T-test, and ANOVA. The meals offered by free meal service centers were not met the 1/3 recommended dietary allowances in calcium and vitamin $B_2$. There were significant differences between dependent variables(nutrient content, nutrient density, nutrient deficiency, NAR, MAR, food group intake patterns) and independent variables (operation type, operation status, operation period, nutritionist, food cost).

Comparison and analysis of peak flow by Areal Reduction Factor (면적감소계수에 따른 첨두유량의 비교연구)

  • Baek, Hyo-Sun;Lee, De-Young;Kang, Young-Buk;Choi, Han-Kuy
    • Proceedings of the Korea Water Resources Association Conference
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    • 2007.05a
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    • pp.1798-1802
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    • 2007
  • The practice of business estimate flood discharge by rainfall-flow relation that is easy collection of observation data. The important factor is rainfall, coefficient of runoff, and drainage area for analysis of runoff-flow relation.The practice of business usually use probability rainfall that use a weighted average value after each observation post estimate probability of non-same time. It has more error than same time probability rainfall, and it can excess of estimation because it can't consider space distribution of rainfall.The study of result showed similar aspect with existing ARF but width of coefficient become smaller. And the comparison of peak flow did not different what used by ARF and same time probability rainfall(A group). But non-same time probability rainfall is bigger 25% more than another(B group). Between A group and B group of the difference increased with the lapse of time.

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3-Phase Current Estimation of SRM Based on the DC-Link Current (직류링크 진류정보를 기반으로 한 SRM 3상전류 추정법)

  • Kim, Ju-Jin;Kim, Seong-Gon;Kim, Tae-Woong;Ahn, Jin-Woo;Choi, Jae-Ho
    • Proceedings of the KIPE Conference
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    • 2005.07a
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    • pp.575-577
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    • 2005
  • This paper proposes the SRM drive system based on DC-link current, from which the phase currents can be estimated in accuracy and also they can be used in driving SRM instead of the three-phase currents. In additional, the detecting circuit for DC-link current is also proposed for increasing the resolution and decreasing the off-set. Comparing to the general drive system based on the phase current, it is verified through the experiment that the proposed SRM drive system has the good performance in steady-state responses of the speed control. Using the DC-link current, all of the 3-phase currents can be easily estimated in driving the SRM.

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Initial Pole Position Estimation Agorithm for PM-LSM by Pseudo-Position Control (준위치제어를 통한 영구자석형 리니어동기모터의 초기자극위치 추정알고리즘)

  • Kim, Tae-Woong;Min, Wan-Ki;Choi, Jae-Ho
    • Proceedings of the KIPE Conference
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    • 2005.07a
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    • pp.578-580
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    • 2005
  • This paper proposes the algorithm for the initial pole-position estimation of a surface PM-LSM, which is carried out under the pseudo-position control with-out a pole sensor and is insensitive to the motor parameters. This algorithm is based on the principle that the initial pole-position is calculated by the reverse trigonometric-function using the two reference currents, which are informed from the speed controller. The effectiveness of the proposed algorithm is confirmed by the arithmetical analysis and the experiment. IPP is well estimated within a satisfied moving-distance and a shorter estimation taken-time even if large disturbance such as cogging and friction are existed.

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Design and Development of Real Time Honeypot System for Collecting the Information of Hacker Activity (실시간 침입자 행동양식 파악 시스템의 설계 및 구현)

  • Seo, Dong-Il;Choi, Yang-Seo;Lee, Sang-Ho
    • Proceedings of the Korea Information Processing Society Conference
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    • 2003.05c
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    • pp.1941-1944
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    • 2003
  • 인터넷이 생활의 한 부분이 되면서 인터넷 사용자가 급증함에 따라 각종 사이버 범죄의 발생 건수 역시 크게 증가하고 있다 이러한 각종 사이버 범죄에 대응함에 있어서 가장 심각한 문제 중의 하나는 해커가 어떤 기술을 이용하여, 어떠한 방식으로 해킹을 진행하는지에 대한 정보가 매우 부족하다는 것이다. 현재 해커들은 해킹에 성공하기 위해 고도의 해킹 기법과 새로운 취약점을 이용하고 있는 반면, 해킹 방지를 위해 사용되고 있는 보안 강화 시스템들은 새로운 방식을 이용하는 해킹 시도를 효율적으로 방어하지 못하고 있는 것이 현실이다. 이와 같은 문제점을 해결하기 위해 제안된 것이 해커의 행동 양식에 대한 정보를 얻기 위한 침입유도 시스템(Honeypot)이다. 그러나 기존의 침입유도 시스템은 해커의 행동 양식 파악에 전문적인 기술이 필요하여 실시간 정보분석이 용이하지 못했다. 이에 본 논문에서는 해커의 행동양식을 실시간으로 파악하고 분석하는 허니넷(Honeynet) 형태의 침입자 행동양식 파악 시스템(Honeypot)을 설계하고 개발하였다.

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The Change of Shoulder Flexion by Degree of Freedom in The Individuals (운동자유도에 따른 어깨관절 굴곡각도의 변화)

  • Kim, Tae-Yoon;Choi, Jae-Won
    • PNF and Movement
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    • v.7 no.1
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    • pp.25-32
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    • 2009
  • Objective : The purpose of this study was conducted to find the change of shoulder flexion by degree of freedom between the Proprioceptive Neuromuscular Facilitation(PNF) pattern, the flexion- abduction- external rotation, and not PNF pattern, the flexion- exteral rotation(except abduction)movement. Method : PNF pattern applied on the unilateral upper extremity in all subjects were the flexion- abduction- external rotation, and not PNF pattern, and twenty-six normal subjects(13 male, 13 female) were tested by Cybex Norm Testing & Rehabilitation System. Results : PNF pattern showed significant increase of flexion than not PNF pattern, the flexion-exteral rotation(except abduction)movement, and also the female group was significantly increased than male group. Conclusion : The results suggested that the application of PNF pattern to the unilateral upper extremity had affected on the shoulder flexion by degree of freedom.

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