• 한국양식학회지
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• 제16권2호
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• pp.69-75
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• 2003

Genetic variability and population structure of 11 natural ayu, Plecoglossus altivelis populations and one hatchery stock were assessed by starch gel electrophoretic analysis with 10 enzyme coding loci. Three loci were polymorphic (lower than 0.95 in major allele frequency) in natural populations,2 loci in hatchery stock. The average number of alleles per locus was 1.38. Observed heterozygosities ranged from 0.0235 to 0.088 (0.055 on the average) in natural population while 0.0925 in hatchery stock. The genetic distance among natural populations measured 0.000047-0.005407 and no significant differentiation was observed among them. On the other hand, a signifcant genetic distance was found between natural populations and the hatchery stock with measuring 0.002032-0.O08605. The results in this study suggest that the hatchery stock has diverged from natural populations, and also that careful to maintain sustainable and effective population size (parents number) should be made.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.202-205
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• 2003

The performance of space-frequency trellis coded (SFTC) OFDM system is analyzed in frequency selective fading channel. Using a pairwise error probability upper bound expression, we design the code and interleaver that can maximize the diversity and coding gain. To alleviate the performance degradation due to the inter-antenna product terms, we propose a new SFTC scheme that employs non-overlapped interleaving for each antenna A new code is optimized for the non-overlapped interleaving and a practical sub-optimal decoding algorithm is proposed. It is shown that the proposed scheme can substantially improve the performance compared to the conventional scheme that employs identical interleaving for all antennas.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.473-476
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• 2003

In this paper, presents a way to maximize transmission efficiency and reception ability through transmission diversity technology, which can be adapted to wireless multimedia OFDM system. The presented method is a comparative analysis between a case where parameter a for time average is 0.3, 1 with consideration of channel presumption with two types of rms delayed proliferation, which is 50nsec, 150nsec, for the performance analysis of STTC(Space-Time Trellis Code) using time-space code method appropriate for MIMO channel, and performance in the case where presumed channel value from long training column section is applied to according frame in a single frame. The result showed that BER brought SNR improvement of 1.0dB in 10$^{-3}$ when a was 0.3 than using only the long training column, and showed increase of general performance improvement for the sake of time average rather than the case without.

• 한국통신학회논문지
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• 제18권9호
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• pp.1323-1331
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• 1993

내다중파특성을 갖는 변복조 방식을 소개하고 이의 지연검사 특성을 통하여 DSK의 내다중성에 대한 기본원리를 분석한다. 정보심볼구간 T의 한가운데인 T/2에서 위상변화를 갖도록하여 얻을 수 있는 다이버시티 효과에 대해서도 검토한다. 기본방식의 하나인 DSK의 대역폭에 대한 특성을 개선하기 위하여 다변화한 $ heta$-DSK의 위상과 모양함수를 변화시켜 특성을 연구한다.

• Fisheries and Aquatic Sciences
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• 제12권1호
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• pp.35-43
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• 2009

Sturgeons and paddlefishes are frequently referred to as 'living fossils' among the actionpterygian lineage. They are increasingly facing threats to their existence because of various anthropogenic pressures. In this study, we present the complete mitogenome sequence of the Russian sturgeon Acipenser gueldenstaedtii (Acipenseriformes; Acipenseridae). The mitogenome showed highly homogeneous molecular features compared to previously known vertebrate mitogenomes. Phylogenetic tree inferred from concatenated protein-coding and tRNA genes unambiguously revealed the monophyly of A. gueldenstaedtii, Acipenser stellatus, and Huso huso. Genetic information of the endangered A. gueldenstaedtii will provide baseline data needed to develop molecular markers for stock identification and assessment of population diversity and also to develop future conservation strategies.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2111-2113
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• 2002

This paper proposes the design of PI controller using real-coding genetic algorithm showing a good performance on convergence velocity and diversity of population among evolutionary computations. To evaluate the proposed method's effectiveness, we apply the proposed GA-PI controller to the speed control of an actual DC servomotor system. The experimental results show that GA-PI controller has the better control performance than PI controller in terms of settling time rising time and overshoot.

• 한국정보시스템학회지:정보시스템연구
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• 제29권1호
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• pp.181-199
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• 2020

Purpose The purpose of this study is to analyze the current state of grounded theory methodology in Korea information systems studies and to suggest its application strategies. Design/methodology/approach After reviewing previous studies, this study reviewed 16 papers which adopted grounded theory methodology and analyzed these papers by two ways, research contents and methods adopted from grounded theory methodology: Main characteristics in grounded theory methodology are selected as main criteria in analysis such as data collection method, constant comparison, software use, coding ways, suggested model, proposition suggestion etc., while subject, theory/practice orientation, and role of prior knowledge are included in research contents. Findings Based on the review and analysis, this paper suggested four guidelines for adopting grounded theory methodology to information systems research in Korea: First, division of research methodology into stages. Second, explicit documentation of research process. Third, pursuit of diversity in research topics. Fourth, strengthening scale up and theoretical integration.

• Journal of Communications and Networks
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• 제14권2호
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• pp.206-212
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• 2012

In this paper, in order to effectively apply unitary space-time modulation to the direct-sequence spread-spectrum multiple-access (DSSS-MA) networks, we propose a low-rate, noncoherent, unitary, and space-time modulated DSSS system supporting any number of transmit antennas based on Walsh matrices. The proposed scheme simultaneously performs bandwidth spreading and space-time coding and outperforms those using high-rate, conventional unitary space-time constellations. Furthermore, the proposed scheme allows for a simple detector structure based on fast Walsh transforms.

• Journal of Communications and Networks
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• 제12권3호
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• pp.240-245
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• 2010

Jacket matrices, motivated by the complex Hadamard matrix, have played important roles in signal processing, communications, image compression, cryptography, etc. In this paper, we suggest a novel approach to design a simple class of space-time block codes (STBCs) to reduce its peak-to-average power ratio. The proposed code provides coding gain due to the characteristics of the complex Hadamard matrix, which is a special case of Jacket matrices. Also, it can achieve full rate and full diversity with the simple decoding. Simulations show the good performance of the proposed codes in terms of symbol error rate. For generality, a kind of quasi-orthogonal STBC may be similarly designed with the improved performance.

• 디지털콘텐츠학회 논문지
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• 제6권4호
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• pp.243-248
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• 2005

본 논문에서는 효율적인 스트리밍 전송을 위한 합성변조 CDMA시스템을 제안하고 전송 채널 환경은 나카가미 페이딩 모델을 도입하고 전자기기에서 방출되는 임펄스 간섭파를 채널 환경으로 모델링하여 합성변조기법을 채용한 CDMA 시스템의 성능을 분석하였다. 또한 MRC 다이버시티 기법과 BCH 코딩 기법을 이용하여 열화된 시스템 성능을 개선하였다.