• ETRI Journal
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• v.28 no.1
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• pp.95-98
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• 2006

In this letter, a novel M-ary code-selected direct sequence (DS) ultra-wideband (UWB) communication system is presented. Our purpose is to achieve a high data rate by an M-ary code-selected direct sequence bipolar pulse amplitude modulation (MCSDS-BPAM) scheme. In this system, a particular DS code sequence is selected by the $log_2M$/2 bits from the DS gold code set. This scheme can accomplish both a high data rate without increasing the system bandwidth or changing the pulse shape and improve the BER with an increase of modulation level M even at a lower signal-to-noise ratio (SNR). The receiver signal processing algorithm is given for an MCSDS-BPAM UWB system over an ideal AWGN channel and correlation receivers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1322-1331
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• 2000

In this paper, we compare the performance of noncoherent DS-CDMA system where orthogonal code is used for identifying the user to reduce multiple access interference or for M-ary orthogonal signaling to improve the performance of demodulation. The effects of M-ary orthogonal signaling on the noncoherent demodulation is investigated and compared with one of coherent demodulation. The analysis results show that M-ary orthogonal signaling gives better performance than quasi-synchronous orthogonal scheme for a moderate number of users when the processing gain is 128 over AWGN channel. In addition, when the number of user is 41, M=64 orthogonal signaling has a similar performance to the quasi-synchronous orthogonal scheme at the BER of 10-2 when the time misalignment between channels is within 1/2 chip and M=256 orthogonal signaling always outperforms the quasi-synchronous orthogonal scheme. Start after striking space key 2 times.

• Proceedings of the KIEE Conference
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• summer
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• pp.313-315
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• 2004

최근의 전력선통신(PLC: Power Line Communication)은 협대역인 450KHz에서 광대역인 30MHz로 확대되어 고속의 데이터 전송이 가능하게 되었다[1]. 본 논문에서는 광대역 채널특성과 더불어 고속의 데이터 전송까지 가능하도록 하기 위해 새로운M-ary SS(spread spectrum) 기반의 고속 전력선통신시스템을 제시하고 임펄스잡음과 같은 전력선 채널환경 하에서의 BER(Bite Error Rate)특성에 대한 모의실험을 거쳐서 제안 방식의 유용성을 확인하였다

• Kyungpook Mathematical Journal
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• v.55 no.3
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• pp.515-530
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• 2015

We say that (R, f, g) is an additive (m, n)-semihyperring if R is a non-empty set, f is an m-ary associative hyperoperation, g is an n-ary associative operation and g is distributive with respect to f. In this paper, we describe a number of characterizations of additive (m, n)-semihyperrings which generalize well-known results. Also, we consider distinguished elements, hyperideals, Rees factors and regular relations. Later, we give a natural method to derive the quotient (m, n)-semihyperring.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10C
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• pp.836-843
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• 2008

In this paper we derive the theoretical performance of orthogonal STBC algorithms in spatially correlated Rayleigh fading environments and compare their performances for various correlation conditions. We first derive the theoretical BER of the orthogonal STBC algorithms for both M-ary PSK and M-ary QAM modulation schemes by using the eigenvalues of the channel correlation matrix and then investigate the effect of the spatial correlation on the performance for various transmission rates of $1{\sim}4bps/Hz$. Performance analysis illustrates that the Alamouti scheme provides the better performance than the Tarokh scheme for all the transmission rates in highly correlated fading environments with a correlation being larger than 0.9.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.12-19
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• 2014

In this paper, an advanced UWB (ultra wideband) Rake receiving technique based on the statistical distribution model is studied in the M-ary TH-PPM system with multiple access interference (MAI). In order to improve the performance of the Rake receiver, the stochastic model, which can flexibly express the behavior of MAI-plus-noise, is required and the Laplace distribution and the generalized normal Laplace (GNL) model applied by the curtosis matching method are considered. The performance of Rake receiver based on each probability distribution is evaluated in the IEEE multipath fading channel and compared to that of the conventional Rake receiver. The suggested approach shows a superior BER performance than that of conventional Rake receiver.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.635-638
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• 2008

본 연구는 웹이나 정보 검색 환경에서 사용자로부터 입력되는 단순한 키워드 형태의 질의가 아닌 문장형태의 질의에 있어 문장이 내포하는 질의의 의미를 결정하여 더 정확한 검색 결과를 제공하기 위해 온톨로지 내 개념들 간의 속성간 연결을 위해 A-Box 기반의 관계 선언과 새로운 N-ary 개체 관계 방법을 제안한다. 특히 개념 개체들 간의 의미를 더 정확히 결정하기 위해 기존의 N-ary 개체 관계 방법이 갖고 있는 속성에 가중치를 포함하는 것이 아니라 가중치에 관련된 새로운 개체를 생성 패턴을 제시하여 특정 개념에 연관된 개념들의 관련성 결정의 성능을 높이도록 하였다. 본 연구의 실험에 있어 사용자가 입력한 병증의 문장을 결정하기 위해, A-Box 기반의 관계 선언과 N-ary 디자인 패턴에 결합하는 지식 도메인 온톨로지 등을 구축하였으며, 이를 통한 실험 결과 문장의 의미에 따른 더 정확한 결과를 보여주었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11C
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• pp.1045-1052
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• 2005

The symbol error probability of M-ary PSK (MPSK) and QAM (MQAM) systems using the branch with the largest signal-to-noise ratio (SNR) at the output of L-branch selection combining (SC) in frequency-nonselective slow Nakagami fading channels with an additive white Gaussian noise (AWGN) is derived theoretically For integer values of the Nakagami fading parameter m, the general formula for evaluating symbol error rate (SER) of MPSK signals in the independent branch diversity system comprises numerical analyses with the integral-form expressions. An exact closed-form SER performance of MQAM signals under the effect of SC diversity via numerical integration is presented. These performance evaluations allow designers to determine M-ary modulation methods for Nakagami fading channels.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.9C
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• pp.835-842
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• 2003

For an odd prime p and integer n, m and k such that n=(2m＋1)ㆍk, a new family of p-ary sequences of period p$^{n}$ -1 with optimal correlation property is constructed using the p-ary Helleseth-Gong sequences with ideal autocorrelation, where the size of the sequence family is p$^{n}$ . That is, the maximum nontrivial correlation value R$_{max}$ of all pairs of distinct sequences in the family does not exceed p$^{n}$ 2/ ＋1, which means the optimal correlation property in terms of Welch's lower bound. It is also derived that the linear span of the sequences in the family is (m＋2)ㆍn except for the m-sequence in the family.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.229-233
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• 2003

In this paper we theoretically analyze the probability of error for M-ary pulse position modulation (PPM) ultra-wideband (UWB) multiple access system using Gaussian monopulse. The optimum detection of UWB signals using M-ary orthogonal PPM in additive white Gaussian noise (AWGN) and multiple access interference (MAI) is considered, then receiver signal to noise power ratio (SNR) and upper bound fur the bit error rate (BER) are derived. Numerical results considering some practical parameters are presented.