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김기윤,Kim, Ki-Yun 한국인터넷방송통신학회 2018 한국인터넷방송통신학회 논문지 Vol.18 No.3
본 논문에서는 캡슐 내시경을 위한 HBC(Human Body Communication) 시스템의 종합적인 설계 방법을 제시하였다. 먼저 환자 몸에 부착된 다수의 패치로부터 수신되는 신호를 차동 연산을 통해 합성하는 방법을 제시하고 이를 통한 신호 SNR을 수학적으로 유도하였다. 캡슐에서 보내는 HBC 송신신호를 동기화하기 위한 방법으로 PN 코드를 이용한 대략적 타이밍 동기 방법과 ZCD(Zero Crossing Detector)를 통한 Manchester, NRZ, RZ 변조 기법간의 미세 타이밍 동기 성능을 분석하였다. 아울러 HBC 신호 프레임을 Rician 및 Rayleigh 채널 환경에서 적용하였을 때의 등화 성능을 LMS 및 RLS 알고리즘을 적용하여 평가하였다. In this paper, a comprehensive design of HBC(Human Body Communication) system for capsule endoscope is presented. First, we propose a method of combining the signals received from multiple patches attached to the body of patient through differential operation and derive the signal SNR mathematically. To synchronize HBC transmission signal sent from capsule, we analyzed coarse timing synchronization method using PN code and fine timing synchronization performance among Manchester, NRZ and RZ modulation method using ZCD(Zero Crossing Detector). In addition, we evaluated the equalization performance of HBC signal frame in Rician and Rayleigh channel environments by applying LMS and RLS algorithm.
High-Order QAM에 적합한 반송파 동기회로 설계 - I부. 넓은 주파수 포착범위를 가지는 위상검출기 설계 및 분석
김기윤,조병학,최형진,Kim, Ki-Yun,Cho, Byung-Hak,Choi, Hyung-Jin 대한전자공학회 2001 電子工學會論文誌-TC (Telecommunications) Vol.38 No.4
본 논문에서는 High-Order QAM(Quandrature Amplitude Modulation)을 적용하는 모뎀에서 강인하고 넓은 범위의 주파수 포착 범위를 가지는 극성판단(Polarity Decision) 반송파 동기용 PD(Phase Detector) 알고리즘을 제안하고 이에 대한 평균 출력특성(S-curve)과 분산특성을 수학적으로 유도하여 기존의 DD(Decision Directed)방식과 비교 분석한다. 기존의 DD 방식의 선형영역은 256 QAM의 경우 $3.5^{\circ}{\sim}3.5^{\circ}$ 이었으나 제안한 알고리즘의 선형영역은 ${\gamma}-17.9$에서 $36^{\circ}{\sim}36^{\circ}$ 의 넓은 구간을 가진다. 또한 기존의 DD 방식에서는 256 QAM의 주파수 오프셋 포착 성능이 ${\pm}10\;KHz$ 이하였다. 이는 아날로그 front-end 회로에서 주파수 오프셋이 일반적으로 ${\pm}100\;KHz$ 정도까지 줄어들 수 잇는 것을 감안하면 AFC(Automatic Frequency Control) 또는 반송파 복구를 위한 보조적인 위상검출회로가 필요하게 됨을 의미한다. 그러나 제안된 극성판단 반송파 동기 알고리즘을 사용하면 보조적인 회로의 도움없이 SNR = 30 dB에서 최대 ${\pm}300\;KHz$의 주파수 오프셋까지도 포착 가능하다. In this paper, we propose a polarity decision carrier recovery algorithm for high order QAM(Quadrature Amplitude Modulation), which has robust and large frequency acquisition performance in the high order QAM modem. The proposed polarity decision PD(Phase Detector) output and its variance characteristic are mathematically derived and the simulation results are compared with conventional DD(Decision-Directed) method. While the conventional DD algorithm has linear range of $3.5^{\circ}{\sim}3.5^{\circ}$, the proposed polarity decision PD algorithm has linear range as large as $-36^{\circ}{\sim}36^{\circ}$ at ${\gamma}-17.9$. The conventional DD algorithm can only acquire offsets less than ${\pm}10\;KHz$ in the case of the 256 QAM while an analog front-end circuit generally can reduce the carrier-frequency offset down to only ${\pm}100\;KHz$. Thus, in this case additional AFC or phase detection circuit for carrier recovery is required. But by adopting the proposed polarity decision algorithm, we can find the system can acquire up to ${\pm}300\;KHz$at SNR = 30dB without aided circuit.
건강진단자에서 복부초음파검사상 나타난 공간점유간병소에 대한 임상적 고찰
김기윤(Ki Yun Kim),이헌주(Heon Ju Lee),서정일(Jeong Ill Suh),박찬원(Chan Won Back),이동준(Dong Jun Lee),송영두(Young Doo Song),도갑석(Gab Suk Doh),전경진(Kweong Jin Jeon),김준환(Jun Hawn Kim) 대한내과학회 1996 대한내과학회지 Vol.51 No.2
N/A Objectives: Ultrasonography(USG) is widely used for the screening and detection of liver SOL in pa- tients with acute and chronic hepatopathy, but the prevalence of liver SOL on a nonselected population by ultrasonographic screening examination is not well know. We experienced some patients with liver SOL in a automated med-screening center visitor by USG and reviewed the prevalence and clinical aspects of liver SOL detected by USG in a view of dynamic relation to hepatoma. Methods: Form March 1983 to April 1994, USG was performed on 27,140 visitors from a urban and suburban area of Taegu city. Initial USG of the liver was followed by follow up USG and other imaging modalities in case it was necessary. Results: 1) Liver SOL was detected in 337 cases(1.24%) of 27140 examinees by initial screening USG. 2) Among 337 cases of liver SOL 226(67.1%) of cyst, 19(5.7%) of hepatoma, 15(4.5%) of hemangioma, 12(3.6%) of polycystic kidney, 2(0.6%) of metastatic cancer, 1(0.3%) of abscess, 22(6.5%) of false positive finding without SOL and 40 cases(11.9%) of nonspecific questionable SOL without confirmation were noted at the end. 3) The sensitivity of USG detecting liver SOL was 93.5% and 100.0%, 93.3% and 94.7 in cyst, hemangioma and hepatoma respectively. False positivity of USG was 6.5%. 4) The incidence rate of hepatoma is presumed to be 8.1 and 3.5 per 100,000 in male nad female, respectively. Coclusion: The prevalence of liver SOL in general population by USG screening was presumed to be 1.24%. USG screening and follow up examination might be needed for the detection of benign and
김기윤(Ki-Yun Kim),함광근(Kwang-Keun Ham),정춘병(Choon-Byeong Chung) 한국조명·전기설비학회 2010 한국조명·전기설비학회 학술대회논문집 Vol.2010 No.5월
In this paper we investigate medical applications of LED. As prominent medical techniques, we analyze skin healing technique, UV-LED technique, high-power LED photopolymerization technique and LED medical light technique. Also, we show several examples of medical implementation of LED and analyze their technical characteristics.