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저전력의 eMTC 시스템에 적합한 동기화 오차 추정 기법
정용안(Yong-An Jung),변상봉(Sang-Bong Byun),조수현(Soo-Hyun Cho),이성훈(Sung-Hun Lee) 한국정보기술학회 2020 한국정보기술학회논문지 Vol.18 No.10
A major issue of machine type communication (MTC) is to serve a better coverage enhancement with low-power consumption for Internet of Things (IoT) devices. Due to the restriction on total power allowed for transmission, it is necessary to estimate frequency offset in low signal to noise ratio (SNR) like as -15dB. In this paper, an improved frequency offset detection scheme is proposed for low-power IoT devices in the cellular-based eMTC system. The repetitive character of the physical broadcast channel (PBCH) symbols and the channel estimation based weight are considered for the improved frequency offset estimation. It is demonstrated that the proposed estimator is more efficient for coverage enhancement of eMTC devices by computer simulation.
축구선수들이 선호하는 지도행동유형에 따른 선수만족 및 경기력의 관계
정용안(Yong An Jung) 한국사회체육학회 2009 한국사회체육학회지 Vol.0 No.38
The main purpose of this research is to analyze the differences between the high school soccer players preference according to leader type behaviour. Also, the investigation of the relationship between the athletes` satisfaction and performance and how it effects the leader behavior. The reason is to learn about how to improve the athletes` satisfaction and performance in competition. The result are as follows; First, there were significant differences in soccer players` preference to a leader`s behavior type according to socio-demographic variables. Second, the player`s preference of leader style had a partially statistically influence on athletes` satisfaction. Third, the player`s preference of leader style had a partially statistically influence on performance.
CP-OFDM 기반 통신 시스템을 위한 주파수 동기화 오차 추정 기법
정용안(Jung Yong An),변상봉(Byun Sang Bong),신한재(Shin Han Jae),한동철(Han Dong Cheul),조수현(Cho Soo Hyun),이성훈(Lee Sung Hun) 한국통신학회 2021 한국통신학회 학술대회논문집 Vol.2021 No.6
3GPP 5G NR 표준에서는 고속의 데이터 전송 및 주파수 선택적 페이딩 채널에 강건함을 위해 cyclic prefix orthogonal frequency division multiplexing (CP-OFDM)과 discrete Fourier transform spread OFDM (DFT-S-OFDM)을 채택하였다. OFDM 기반의 전송 방식은 각 서브캐리어들을 직교하게 중첩시켜 병렬전송함으로써 고속의 데이터 전송을 가능하게 하지만, 동기화 오차에 매우 민감하다. 특히 소수배 주파수 오차가 존재할 경우 직교성을 상실하게 되어 ICI가 발생하게 되고, 이는 시스템의 성능 저하를 발생시킨다. 이를 해결하기 위해 본 논문에서는 primary synchronization signal (PSS) 및 secondary synchronization signal (SSS)를 이용한 잔여 주파수 오차 추정기법을 제안한다. 컴퓨터 모의실험을 통해 5G NR의 채널 모델을 적용시키며 제안된 기법의 성능을 검증하였으며, 5G NR 시스템에 쉽게 적용할 수 있음을 확인하였다.
Tc-99m Pertechnetate / TI-201 감영 신티그라피에서 부갑상선 선종으로 오인된 흉선종 1 예
정용안(Yong An Chung),유이령(Ie Ryung Yoo),김성훈(Seong Jang Kim),정수교(Soo Kyo Chung),왕영필(Young Pil Wang),정지한(Ji Han Jung),이교영(Kyo Young Lee),김병기(Byung Kee Kim) 대한핵의학회 2001 핵의학 분자영상 Vol.35 No.4
A large superior mediastinal mass was found incidentally by ultrasonography in a 60-year-old man. There was an abnormal accumulation of Tl-201 in the lower pole of left thyroid gland, extending into left superior mediastinum on Tc-99m pertechnetate/Tl-201 subtraction scan. Laboratory findings relating thyroid and parathyroid were all within normal range. We considered the mass as a non-functioning parathyroid adenoma tentatively. However, subsequent surgery and pathologic examination revealed the mass to be a benign mixed thymoma. We report a case of patient with thymoma showing unusual Tc-99m pertechnetate/Tl-201 subtraction imaging and laboratory findings, and suggest to consider the possibility of other mediastinal tumors rather than parathyroid adenoma. (Korean J Nucl Med 2001;35:274-279)