• Title/Summary/Keyword: 선루프

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Analysis of Input Impedance for PWM DC-DC Converters (PWM DC-DC 변환기의 입력 임피던스 해석)

  • Kim, Dong-Soo;Son, Dong-Kook;Choi, Byung-Cho
    • Proceedings of the KIPE Conference
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    • 2005.07a
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    • pp.272-274
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    • 2005
  • 본 논문은 PWM DC-DC 변환기의 입력 임피던스를 Middlebrook의 EET (Extra Element Theorem)를 사용하여 해석할 수 있는 방법을 제시하고, 이를 이용하여 실제로 전압 제어, 전류 제어 승압형 변환기에 대한 입력 임피던스를 해석하였다. 유도된 수식은 간략화, 근사화를 통하여 보드 선도 (Bode plot)화 하였고, 입력 임피던스 특성 및 전류 루프, 피드백/피드포워드 루프, 전압루프의 영향을 해석하였다. 또한 이론적 해석은 컴퓨터시뮬레이션 결과 및 실제 제작된 PWM DC-DC 변환기의 실험 결과로 비교, 검증하였다.

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칼만필터를 이용한 Baro-Inertial 고도루프의 설계 및 성능분석

  • Kim, Hyeon-Seok;Lee, Yun-Seon;Je, Chang-Hae
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.2
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    • pp.455-458
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    • 2006
  • 관성항법장치는 관성항법장치를 구성하는 관성센서인 가속도계 및 자이로의 오차요소에 의해 수평축 항법오차는 슐러주기를 가지고 서서히 증가하는 반면에 수직축 오차는 기하급수적으로 증가하는 특성을 가지고 있다. 그러므로 관성항법장치를 장시간 운용하는 경우에는 비관성 보조센서를 이용하여 관성항법장치의 수직축 항법오차에 대한 보정을 반드시 수행하여야 한다. 관성항법장치의 수직축 항법오차를 보정하기 위한 비관성 보조센서의 일종인 기압고도계는 계측된 대기압과 모델링 된 대기압을 비교하여 항체의 고도를 측정하는 방법을 이용하기 때문에 항체의 자세변화 등에 매우 민감하고 대기압 측정오차에 의해 매우 큰 진폭의 잡음 및 바이어스가 존재한다. 본 논문에서는 시뮬레이션 및 시험을 통하여 기압 고도계의 잡음 및 바이어스 오차 성분에 의한 baro-inertial 고도루프의 성능분석 결과를 제시하고 기압고도계 잡음에 둔감한 INS/기압고도계 칼만필터의 설계 결과를 제시한다.

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Capacitively Loaded Loop Antenna Fed with Metamaterial Balun (Metamaterial 발룬으로 급전된 Capacitively Loaded 루프 안테나)

  • Jung, Youn-Kwon;Lee, Bom-Son
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.10
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    • pp.1084-1090
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    • 2009
  • This paper presents a balun consisting of a T-junction, a Right/Left Handed Transmission line(RLH-TL), and a conventional Right Handed(RH) line. It is assumed that the RLH-TL consists of N unit-cells. We provide closed-form solutions and design a very compact wideband(80 %) balun using CPW lines based on the obtained solutions. Then, we propose a capacitively loaded loop antenna designed for a uniform current distribution. The antenna resistance of the proposed antenna at resonance is about 204 ohms. The length of the unit cell is about $\lambda/12$(total length: $1\;\lambda$). The magnetic field generated from the proposed antenna is stronger than that of the conventional one by as much as 20 dB. We used a coplanar strip line(CPS) to combine the loop antenna and balun. The proposed antenna may be used as a near field UHF RFID reader antenna.

Design of Loop Antenna Using Coplanar Waveguide Feeding Method (동일면 도파관 급전방식을 이용한 루프안테나 설계)

  • Yeo, Junho;Lee, Jong-Ig
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2017.10a
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    • pp.55-56
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    • 2017
  • In this paper, a wideband loop antenna is designed using a CPW feeding method for indoor digital TV applications. The proposed loop antenna consists of a square loop and two circular sectors which connect the loop with central feed points, and the CPW feed line is inserted in the lower circular sector. The CPW feed line is designed to match with the 75 ohm port impedance for DTV applications, and the ground slots are etched in order to improve the impedance matching in the middle frequency region. The optimized antenna is fabricated on FR4 substrate, and the experiment results show that it operates in the frequency band of 463-1,280 MHz for a VSWR < 2, which assures the operation in the DTV band.

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CPW-fed Wideband Loop Antenna for Indoor Digital TV Applications (실내 디지털 TV용 CPW-급전 광대역 루프 안테나)

  • Yeo, Junho;Lee, Jong-Ig
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.8
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    • pp.1492-1497
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    • 2017
  • In this paper, a design method for a CPW-fed wideband loop antenna for indoor digital TV applications is studied. The proposed loop antenna consists of a square loop and two circular sectors which connect the loop with central feed points, and the CPW feed line is inserted in the lower circular sector. The CPW feed line is designed to match with the 75 ohm port impedance for DTV applications, and the ground slots are etched in order to improve the impedance matching in the middle frequency region. The effects of the gap between the circular sectors and the location and dimension of the ground slots on the input reflection coefficient and gain characteristics are examined to obtain the optimal design parameters. The optimized antenna is fabricated on FR4 substrate, and the experiment results show that it operates in the frequency band of 463-1,280 MHz for a VSWR < 2, which assures the operation in the DTV band.

Design of Compact Wideband Loop Antenna with Horizontal Slits for Terrestrial DTV and UHD TV Applications (지상파 DTV 및 UHD TV용 수평 슬릿이 추가된 소형 광대역 루프 안테나 설계)

  • Yeo, Junho;Lee, Jong-Ig
    • Journal of Advanced Navigation Technology
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    • v.24 no.6
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    • pp.581-586
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    • 2020
  • In this paper, the design process and method for a compact wideband loop antenna for terrestrial digital TV (DTV) and ultra high definition (UHD) TV applications was proposed. Horizontal slits were added on the two circular sectors of the proposed loop antenna in order to miniaturize the existing wideband loop antenna consisting of a square loop and two circular sectors. A CPW transmission line was inserted in the center of the lower circular sector as a feed line. The CPW feed line was designed using the 75 ohm port impedance for DTV and UHD TV applications, and a tapered center-signal line was designed to improve the impedance matching. The final designed antenna was fabricated on an FR4 substrate with a thickness of 0.8 mm. The experiment results show that the proposed compact loop antenna operates in the frequency band of 444.3-820.1 MHz for a VSWR < 2, which fully covers the DTV and UHD TV bands.

Examining causal relationships between regulation and national competitiveness using system dynamics method (규제와 국가경쟁력간의 인과관계)

  • Choi, Young-Chool
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.8 no.7
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    • pp.137-147
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    • 2018
  • Up until now, Korea has been recognized as one of the most severe and strict countries in terms of social regulation. As a result of that, it is generally accepted that economic activities in private sector have been contracted to some extent, weakening national competitiveness. Under this background, this paper examines the complex relationships among factors affecting national competitiveness and regulation and also seeks to discover feedback loops associated with its relationship. The research result shows that reinforcing feedback and balancing feedback loops are found in the system concerned with national competitiveness and regulation. Accordingly, it implies that we need to pay our attention to the management of those loops in order to discover the optimal point striking the balance between regulation and deregulation in terms of national competitiveness. It also implies that we need to conduct sensitivity analysis to forecast the potential results which the scenarios will bring about.

LQ-servo Design Method Using Convex Optimization (I) Frequency Domain Approach (볼록형 최적화기법을 이용한 LQ-서보 설계 방법(I) 주파수 영역에서의 접근)

  • 이응석;서병설
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.7B
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    • pp.1282-1291
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    • 2000
  • 기존의 LQ-서보형 PI 설계방법은 보드선도 상에서 저주파와 고주파 영역에서의 루프전단함수의 특이값 일치에 기이한 설계상의 문제를 가지고 있다. 이러한 점을 해결하기 위해 역 최적제어와 볼록형 최적화기법에 기초한 새로운 설계 방법을 제안하고자 한다.

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나이퀴스트 선도 및 보우드 선도를 이용한 폐루프 제어시스템의 안정도 판별

  • Gang, Tae-Sam
    • ICROS
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    • v.16 no.4
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    • pp.35-41
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    • 2010
  • 나이퀴스트 선도와 보우드 선도는 주파수 영역에서 시스템의 안정성을 판별하는 중요한 수단이다. 본 소고에서는 나이퀴스트 판별법의 근간이 되는 편각의 원리, 그리고 이에 기초한 나이퀴스트 판별법, 이를 활용한 안정도 및 안정도 여유 판별법, 그리고 나이퀴스트 선도와 보우드 선도와의 관계 및 활용시의 장단점을 비교함으로써, 제어기 설계시 도움이 되도록 하였다.