• 한국항해항만학회지
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• 제30권2호
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• pp.167-172
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• 2006

In this paper, the issue of blind detection of Alamouti-type differential space-time (ST) ${\pi}/2$-shifted BPSK modulation in static Rayleigh fading channels is considered. We introduce a novel transformation to the received signal from each receiver antenna such that this binary ST modulation, which has a second-order transmit-diversity, is equivalent to QPSK modulation with second-order receive-diversity. The pre-detection combining of the result of transformation allows us to apply a low complexity detection technique specifically designed for receive-diversity, namely, scalar multiple-symbol differential detection (MSDD). With receiver complexity proportional to the observation window length, our receiver can achieve the performance 1.5dB better than that of conventional differential detection ST and 0.5dB worse than that qf a coherent maximum ratio combining receiver (with differential decoding) approximately.

• 한국통신학회논문지
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• 제30권10C호
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• pp.999-1006
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• 2005

차분 문턱값 검정에서는 (difference threshold test: DTT) 에너지 검파기 출력들 가운데 가장 큰 출력과 둘째로 큰 출력의 차이가 문턱값을 넘지 않으면 심벌을 잃음으로 본다. 변조 크기와 다양성 차수가 유한하면, M진 주파수 편이 신호를 검파할 때 차분 문턱값 검정이 비율 문턱값 검정보다 (ratio threshold test: RTT) 성능이 좋다는 것을 보이고, 변조 크기와 다양성 차수가 무한히 클 때의 점근 성능을 알아본다. 차분 문턱값 검정을 쓰거나 비율 문턱값 검정을 쓰거나 잘못 없이 통신할 수 있는 가장 작은 신호대잡음비는 같다는 것을 보인다.

• 한국지능시스템학회논문지
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• 제11권3호
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• pp.191-199
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• 2001

유전자알고리듬(Genetic Algorithm)은 확률적인 집단 탐색법이고 적응도함수의 형태에 관계없는 직접 탐색법이기 때문에 최근 최적화 방법으로 주목을 받고 있다. 본 논문에서는 Job-shop Schedule Problem에 대하여 교배방법으로 JOX를 사용하며, 효율적인 탐색을 위하여 탐색범위를 축소시키는 강제조작을 형질유전을 고려한 형질유전GT법을 제안하고, 세대교체에 있어 모집단의 다양성을 유지하기 위하여 집단 내에 동일한 개체를 배제하는 방법을 제안한다. 제안 알고리듬을 Fisher & Thompson의 FT10$\times$10 및 FT20$\times$5 문제에 적용하여 유효성을 실험적으로 검증한다.

• Journal of Communications and Networks
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• 제6권1호
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• pp.1-8
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• 2004

In this paper, we investigate the properties and performance of space-time bit-interleaved coded modulation (STBICM) systems in fast Rayleigh fading channels. We first show that ST-BICM with QPSK signaling in fast fading channels possesses the uniform distance property, which makes performance analysis tractable. We also derive the probability distribution of the squared Euclidean distance between space-time symbols assuming uniform bit-interleaving. Based on the distribution, we show that the diversity order for each codeword pair becomes maximized as the frame length becomes sufficiently long. This maximum diversity order property implies that the bit-interleaver transforms an ST-BICM system over transmit diversity channels into an equivalent coded BPSK system over independent fading channels. We analyze the performance of ST-BICM in fast fading channels by deriving an FER upper bound. The derived bound turns out very accurate, requiring only the distance spectrum of the binary channel codes of ST-BICM. Numerical results demonstrate that the bound is tight enough to render an accurate estimate of performance of ST-BICM systems.

• 한국통신학회논문지
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• 제22권12호
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• pp.2696-2705
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• 1997

본 논문에서는 주파수 비선택적 느린 나카가미 m분포의 패이딩올 겪는 MPSK신호의 L-차 선택성 다이버시티에 대한 심벌 오류 확률을 정확한 수식으로 유도한다. 나카가미 페이당 지수 m이 정수일 경우 선택성 다이버시티 합성 기법을 적용시킨 MPSK 선호의 심벌 오류 확률을 유한급수의 형태로 나타낸다. 유도 과정에서 수신신호의 확률 밀도 함수에 대한 새로운 전개가 소개되고 있으며 다양한 수학적 기법을 응용한다. 유도된 수식으로부터 변조 지수 m이 1인 경우 레일리 페이딩 채널에서의 오류 확률이 됨을 확인한다. 다이버시티의 가짓수 L과 페이딩 변조 지수 m을 변화시켜가면서 성능을 분석하여 다이버시티 차수가 증가함에 따라 오류 확률이 감소함을 보인다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.275-275
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• 2022

One of the most widely grown food crops in the world, wheat, is increasing more lodged since for increased rains and winds caused by abnormal climate. During the Green Revolution, shorter wheat cultivars were bred using many Rht genes to increase lodging resistance. However, since only some Rht genes were used for breeding shorter wheat, it may have had a limited impact on wheat breeding and reduced genetic diversity. Therefore, it is essential to search for genes that have breeding potential and affect dwarfism in order to increase the genetic diversity of dwarf characteristics in wheat. In this study, we performed the RNA-seq between 'Keumkang' and 'Komac 5' ('Keumkang' mutant) to analyze the difference in plant height. Differentially expressed genes (DEGs) analysis and Gene function annotation were performed using 265,365,558 mapped reads. Cluster set analysis was performed to compress and select candidate gene DEGs affecting plant height, stem and internode. Gene expression analysis was performed in order to identify the functions of the selected genes by condensing the results of the DEG analysis into a cluster set analysis. This analysis of these plant height-related genes could help reduce plant height, improve lodging resistance, and increase wheat yield. Its application to wheat breeding will also affect the increased genetic diversity of wheat dwarfism.

• Asian-Australasian Journal of Animal Sciences
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• 제33권12호
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• pp.1905-1911
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• 2020

Objective: Tibetan pigs, an excellent species unique to China, face serious threats, which in turn affects the development and utilization of the outstanding advantages of plateau hypoxia adaptability and reduces their genetic diversity. Therefore, a discussion of measures to conserve this genetic resource is necessary. The method, based on genetic diversity, genetic divergence and total genetic contribution rate of population, reflects the priority conservation order and varies depending on the three different purposes of conservation. Methods: We analyzed mitochondrial DNA control region (D-loop) variation in 1,201 individuals from nine Tibetan pig populations across five provinces and downloaded 564 mtDNA D-loop sequences from three indigenous pig breeds in Qinghai, Sichuan, and Yunnan Provinces distributed near the Tibetan pigs. Results: We analyzed three different aspects: Changdu Tibetan pigs have the highest genetic diversity, and from the perspective of genetic diversity, the priority conservation is Changdu Tibetan pigs. Hezuo Tibetan pigs have the highest genetic contribution, so the priority conservation is Hezuo Tibetan pigs in the genetic contribution aspect. Rkaze Tibetan pigs were severely affected by indigenous pig breeds, so if considering from the perspective of introgression, the priority conservation is Rkaze Tibetan pigs. Conclusion: This study evaluated genetic diversity and comprehensively assessed conservation priority from three different aspects in nine Tibetan pig populations.

• Journal of Microbiology and Biotechnology
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• 제20권3호
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• pp.447-459
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• 2010

Bacterial diversity of two distinct wastewater treatment systems, conventional activated sludge (CAS) and membrane bioreactor (MBR), of petroleum refineries were investigated through 16S rRNA gene libraries. Sequencing and phylogenetic analysis showed that the bacterial community composition of sludge samples was distinct between the two wastewater treatment systems. MBR clones belonged predominantly to Class Betaproteobacteria, represented mainly by genera Thiobacillus and Thauera, whereas CAS clones were mostly related to Class Alphaproteobacteria, represented by uncultured bacteria related to Order Parvularculales. Richness estimators ACE and Chao revealed that the diversity observed in both libraries at the species level is an underestimate of the total bacterial diversity present in the environment and further sampling would yield an increased observed diversity. Shannon and Simpson diversity indices were different between the libraries and revealed greater bacterial diversity for the MBR library, considering an evolutionary distance of 0.03. LIBSHUFF analyses revealed that MBR and CAS communities were significantly different at the 95% confidence level ($P{\leq}0.05$) for distances $0{\leq}D{\leq}0.20$. This work described, qualitatively and quantitatively, the structure of bacterial communities in industrial-scale MBR and CAS processes of the wastewater treatment system from petroleum refineries and demonstrated clearly differentiated communities responsible for the stable performance of wastewater treatment plants.

• 한국통신학회논문지
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• 제34권3A호
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• pp.258-264
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• 2009

본 논문에서는 이동 멀티미디어 방송 서비스를 위한 효율적인 협동 다이버시티 기법을 제안한다. 본 논문에서 제안된 방식은 시간에 따라 변화하는 이동위성 채널에 적절하게 대처할 수 있는 전송 다이버시티 기법으로써, 채널 적응에 필요한 채널 품질 정보를 역방향 채널로부터 받을 필요가 없는 기법이다. 제안된 방식은 도심 지역의 음영 문제를 해소하기 위하여 여러 개의 지상 중계기가 설치되어 있는 시스템에서 시공간 블록 부호(Space-Time Block Coding ;STBC)와 더불어 오류정정부호를 동시에 활용하여 협동 다이버시티를 구현할 수 있도록 하는 방식이다. 즉, 위성과 지상 중계기는 서로 협동하여 적절히 시공간 및 채널 부호화된 신호를 전송하고 단말기에서 다이버시티 이득을 얻을 수 있도록 하는 방식이다. 본 논문에서 제시된 시뮬레이션 결과를 통하여 제안된 방식을 통하여 상당한 성능개선을 이룰 수 있음을 확인할 수 있다.

• 지역연구
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• 제15권1호
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• pp.23-43
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• 1999

The strategy of regional industrial specialization is empirically evaluated by examining the relationship between regional industrial structures and economic performances. The regional industrial structure is measured by three industrial diversity indices such as ogive approach, entropy maximizing approach, and economic growth and employment instability in 12 regions is analyzed. According to the time series analysis, we found that the region with more diversified industrial structure experiences more stable in employment. Otherwise, the growth rate of the region with more simplified industrial structure is higher. Therefore, the strategy of industrial specialization is implemented in order to pursuit a rapid economic growth in the short run.