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동기방식 CDMA 시스템의 다원접속 간섭신호 제거 기법
윤동원,김철민 대전대학교 산업기술연구소 1999 산업기술연구소 論文集 Vol.10 No.1
Multiple access interference is the major channel imperfection in DS/CDMA (Direct Sequence Code Division Multiple Access) systems. The achievable channel capacity gains depend strongly on the prevalent interference levels and hence interference cancellation is invoked. Optimal multiuser detection is not interference limited, but it is too complex to be implemented. This paper present very simple multiple access interference cancellation scheme for synchronous DS/CDMA communication system. N-shift cross-orthogonal PN (Pseudo Noise) sequence scheme is presented and discussed. Interference cancellation for synchronous DS/CDMA system using N-shift cross-orthogonal PN sequence is proposed. This system has no cross-talk and no distortion like optimal multiuser detector doesn't have.
이동통신 시스템에서 QAM 신호의 MRC 다이버시티 성능 분석
윤동원 대전대학교 산업기술연구소 2000 산업기술연구소 論文集 Vol.11 No.2
In this paper, we derive and analyze the generalized bit error rate performance expression of M-ary QAM signal for L-branch maximal ratio combining(MRC) diversity reception in frequency-nonselective slow m-distributed multipath fading mobile channel. The multiple branch diversity systems are considered for identical and for different diversity channel fading factors, respectively. The derived results show the MRC diversity performances in terms of BER as a function of the SNR several values of L. A close inspection of results reveals that a significant improvement in performance is achieved as the order of L increases. The results presented are sufficiently general to offer a convenient method to evaluate the BER performance of broadband mobile QAM systems.
동기 MPSK 신호 심볼 오류 확률의 빠른 계산을 위한 간단한 근사식
윤동원,황선태 대전대학교 산업기술연구소 1998 산업기술연구소 論文集 Vol.9 No.2
The symbol error probability for the coherent detection of M-ary PSK signals in AWGN can be evaluated exactly for M = 2 (BPSK) and M = 4 (QPSK). The MPSK symbol error rate(SER) bounds used in the past are simple to calulate, but not particularly accurate. More recently, very tight bounds have been proposed, but they are not true bounds since they are based on an arbitrary truncation of an infinite series expansion. In this paper to obtain the simple and accurate lower bound for coherent MPSK SER in AWGN, we consider the SER for MPSK in Nakagami fading case first. Then as the Nakagami fading index m approaches to the infinite, we obtain the SER for MPSK in AWGN. Here, new lower bound that is simple and very tight is derived.
이동섭,신성윤,이양원 群山大學校 情報通信技術硏究所 1997 情報通信技術硏究論文集 Vol.1 No.-
News-Videos present a significant scene from widespread societies information in short time, It has meaningful data for analyzing that times concerning researching projects for content based retrieval of video. In this paper, we proposed methods of extraction of caption, that has important problem of news videos. that classified three stages, first stage convert images inputed from video frame into YIQ color vector. second stage equalized color histogram of input image, so distribution of region is distinctly. In last stage, we extract caption using edge histogram based on vertical and horizontal line.
Performance Analysis of BER for Quadrature Amplitude Modulation
Yoon, Dong-Weon 대전대학교 산업기술연구소 1999 산업기술연구소 論文集 Vol.10 No.2
현재 사용중인 통신 변조 방식중 멀티미디어 통신에 가장 적합한 직교 진폭 변조에 대하여 16진 신호와 64진 신호에 대한 BER 성능 분석은 이루어진 바 있다 [1], [2]. 그러나 아직까지 일반적인 M진 신호에 대하여 정확한 closed-form에 대한 BER 표현은 구하여 진 바 없다. 이 논문에서는 M진 신호들이 Gray 코딩 되었다는 가정하에 가산성 백색 가우시안 잡음 환경에서 정방형 직교 진폭 변조 신호에 대한 BER 성능을 유도하고 분석한다. The bit error rate (BER) performances for 16 and 64 square quadrature amplitude (QAM) signals are presented in [1], [2]. But the exact general BER expression of M-ary QAM for arbitrary M has not been yet derived out so far. In this paper, a generalized closed-form expression for the BER performance of M-ary square QAM with Gray code bit mapping is derived and analyzed in additive white Gaussian noise (AWGN) channel.
PSK Signal Classification on Mobile Communications
Yoon,Dong Weon 東西大學校 1996 동서논문집 Vol.2 No.1
In this paper, a moments-based modulation type classifier to classify PSK signals over Rayleigh fading channel is proposed and analyzed. The new pdf of received signal is derived from the pdf of phase due to Rayleigh fading using the transformation of random variable. To verify the validity of the derived pdf by applying the likelihood ratio test with the new pdf, the optimum threshold and average BER of BPSK signal in Rayleigh fading are derived. The moments of received signal are evaluated with the exact distribution of the received signal and a moments-based classifier to classify PSK signals is proposed. The performance evaluation of the proposed classifier in terms of the misclassifcation probability for PSK signals has been investigated under Rayleigh fading and AWGN environment.
FCT 1-1 Oral sirolimus (rapamycin) on 22 patients with various types of vascular anomalies
( Dong Hyuk Eun ),( Min Ji Kim ),( Yong Hyun Jang ),( Weon Ju Lee ),( Do Won Kim ),( Ji Yoon Kim ),( Seok-jong Lee ) 대한피부과학회 2016 대한피부과학회 학술발표대회집 Vol.68 No.2
Background: Sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, has been successfully employed for the treatment of carious type of vascular anomalies recently. Objectives: To evaluate the efficacy and safety of using oral sirolimus on vascular anomalies in single-center of a Korean university-setting hospital with cooperation of pediatric oncologist. Methods: Total 22 patients have used oral sirolimus longer than 3 months at vascular anomalies clinic of KNUH (avg.: 6.6±2.6 months). We evaluated therapeutic effects for 3 categories; clinical presentation (size/color/consistency), radiologic evaluation (USG/MRI), and health-related quality of life (pain/function/others). And we paid attention to development of side effect after using sirolimus. Results: Patients included LM/LVM (11 pts, 3 pts with KTS), VM (5 pts), tufted angioma (TA) (4 pts), and AVM (2 pts). Five patients (22.7%) including 3 TA and 2 LM showed improvement in all categories. Seven patients (31.8%) including 5 LM and 2 VM revealed improvement in 2 categories, but 3 patients (13.6%) including 1 LM, 1 AVM and 1 VM did no improvement in all categories. Oral ulcer was developed in 10 cases and diarrhea was occurred in 6 cases. And 2 patients were taken off medication due to severely recurrent oral ulcer. Conclusion: We cautiously suggest sirolimus may be an effective and well-tolerated therapeutic modality in selected patients with complicated vascular anomalies.