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정락규,유흥균 ( Rag Gyu Jung,Heung Gyoon Ryu ) 충북대학교 산업과학기술연구소 1996 산업과학기술연구 논문집 Vol.10 No.2
Abstract_Roman In this paper, cable television transmiasion performance is evaluated according to channel incre ase and cascade canaideration. Evaluation items such as carrier to noise ratio, composite tripl e beat distortion, composite second order dist
협대역 간섭에 강한 적응형 OFDM 통신 시스템 설계와 성능 평가
정락규,김선애,유흥균,Jung Rag-Gyu,Kim Sun-Ae,Ryu Heung-Gyoon 한국전자파학회 2006 한국전자파학회논문지 Vol.17 No.7
열악한 채널 환경에서도 고속으로 통신하는 시스템을 설계하는 것은 매우 중요하다. 고속의 정보 전송이 가능한 FD-OFDM(Frequency Diversity Orthogonal Frequency Division Multiplexing) 통신 시스템은 주파수 다이버시티 특성을 가지므로 일반 OFDM 보다 채널에서 발생하는 잡음이나 간섭에 대항하는 능력이 좋다. 그러나 FD-OFDM 시스템도 협대역 잡음이나 간섭에 성능이 매우 나빠진다. 본 논문에서는 강한 협대역 간섭에도 잘 대처할 수 있는 AFD(Adaptive Frequency Diversity)-OFDM 통신 시스템을 제안하고 통신 성능을 분석한다. 시뮬레이션 결과, 일반 OFDM 방식보다 FD-OFDM 방식은 상당한 성능 개선을 보인다. 또한, AFD-OFDM은 강력한 간섭이 있을 때, FD-OFDM 보다 더 우수한 성능을 보인다. It is important to design the high-speed communication system in the hostile channel. Due to the frequency diversity, FD-OFDM that can be used for the high-speed communication is more robust to the noise or interference than ordinary OFDM. However, even the FD-OFDM becomes degraded in th ε strong narrow band interference channel. In this paper, we propose an AFD-OFDM system and analyze the communication performances in order to find out the more robust communication system in the hostile channel. So, the AFD-OFDM system can cover the drawback of the FD-OFDM and improve the BER performance than FD-OFDM. From the simulation results, FD-OFDM shows better performance than the ordinary OFDM. Furthermore, AFD-OFDM shows more excellent performance than FD-OFDM in the strong narrow interference channel.
이종규(Lee Jong-Gyu),최강민(Choi Kang-Min),이원수(Lee Won-Soo),윤중락(Yoon Jung-Rag) 대한전기학회 2021 대한전기학회 학술대회 논문집 Vol.2021 No.10
In this study, as an inorganic solid electrolyte material, a PEO / LLZO composite solid is a composite of Li7La₃Zr₂O12(LLZO), which has a Cubic structure with a wide electrochemical potential window and high ionic conductivity, and PEO electrolyte PEO, in which the lithium salt is dissociated. We studied the charge / discharge characteristics and impedance characteristics of all-solid-state lithium batteries to which electrolytes were applied. The resistance is minimized when the LLZO content is 20 wt%, which is the condition that the LLZO solid electrolyte is uniformly dispersed in the PEO electrolyte while minimizing aggregation, and the capacitance characteristic is the best at 140 mAh /g. The result is that LLZO acts as a filler in the composite solid electrolyte, which reduces the crystallinity of the PEO and creates a smooth lithium-ion path through interaction with the PEO from the surface of the LLZO solid electrolyte.
Seung-Hwan Lee,Hong-Ki Kim,Min-Gyu Kang,Chong-Yun Kang,Sung-Gap Lee,Young-Hie Lee,Jung-Rag Yoon IEEE 2014 IEEE electron device letters Vol.35 No.7
<P>A formed device embedded-type 0402 sized (Ca<SUB>0.7</SUB>Sr<SUB>0.3</SUB>) (Zr<SUB>0.8</SUB>Ti<SUB>0.2</SUB>)O<SUB>3</SUB> (CSZT) embedded capacitor was fabricated for use in embedded printed circuit board. The capacitance and dielectric loss of the CSZT embedded capacitor were 406.1 pF and 0.015, respectively, at 1 MHz. The CSZT embedded capacitor exhibits stable capacitance with varying applied voltage and C Zero G (-55 °C-125 °C, delta C/C = ±30 ppm/°C) properties. The measured values of equivalent series resistance and equivalent series inductance were 6.1 Ω and 62.39 μH, respectively. The leakage current density was 0.78 μA/cm<SUP>2</SUP> at 3 V of applied voltage. These electrical properties indicate that the CSZT embedded capacitor holds promise for use as an embedded passive capacitor.</P>
고속 스위칭 동작의 주파수 합성기를 위한 하이브리드형 구조 설계와 DLT 대체 회로 연구
이훈희,허근재,정락규,유흥균,Lee Hun-Hee,Heo Keun-Jae,Jung Rag-Gyu,Ryu Heung-Gyoon 한국전자파학회 2004 한국전자파학회논문지 Vol.15 No.12
기존의 PLL(phase locked loop)은 폐루프 구조이므로 주파수 스위칭 속도가 낮은 단점을 갖는다. 이를 개선하기 위해서 개루프 구조를 혼합한 Digital Hybrid PLL 구조를 연구하였다. 또한 이 구조는 빠른 주파수 스위칭 속도로 동작할 수 있지만, VCO의 전압대 주파수 전달특성을 ROM 형태로 구현하는 DLT(digital look-up table)이 사용되어야 하므로 회로소자가 많아지고 소비전력이 증가된다. 그러므로, 본 논문에서는 복잡한 DLT의 구조를 간단한 Digital logic 회로로 대체시킨 새로운 구조를 제안하였다. 또한 주파수 합성때마다 타이밍 동기화를 이루는 회로를 설계하여 합성기의 항상성을 확보하였으며 DLT를 사용하는 방식과 비교하여 회로소자를 약 $28\%$정도 줄일 수 있다. 고속 스위칭 동작 특성과 주파수 합성을 시뮬레이션과 실제 회로 구현으로 확인하였다. The conventional PLL(phase locked loop) frequency synthesizer takes a long switching time because of the inherent closed-loop structure. The digital hybrid PLL(DH-PLL) which includes the open-loop structure into the conventional PLL synthesizer has been studied to overcome this demerit. It operates in high speed, but the hardware complexity and power consumption are the serious problem because the DLT(digital look-up table) is usually implemented by the ROM which contains the transfer characteristic of VCO(voltage controlled oscillator). This paper proposes a new DH-PLL using a very simple DLT-replacement digital logic instead of the complex ROM-type DLT. Also, a timing synchronization circuit for the very small over-shoot and shorter settling time is designed for the ultra fast switching speed at every frequency synthesis. The hardware complexity gets decreased to about $28\%,$ as compared with the conventional DH-PLL. The high speed switching characteristic of the frequency synthesis process can be verified by the computer simulation and the circuit implementation.
유도전동기 벡터제어를 위한 Support Vector Regression을 이용한 회전자자속 추정기
한동창(Dong Chang Han),백운재(Woon Jae Back),김성락(Sung Rag Kim),김한길(Han Kil Kim),이석규(Suk Gyu Lee),박정일(Jung IL Park) Korean Society for Precision Engineering 2005 한국정밀공학회지 Vol.22 No.2
In this paper, a novel rotor flux estimation method of an induction motor using support vector regression(SVR) is presented. Two well-known different flux models with respect to voltage and current are necessary to estimate the rotor flux of an induction motor. Training of SVR which the theory of the SVR algorithm leads to a quadratic programming(QP) problem. The proposed SVR rotor flux estimator guarantees the improvement of performance in the transient and steady state in spite of parameter variation circumstance. The validity and the usefulness of proposed algorithm are throughly verified through numerical simulation.