• Journal of Communications and Networks
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• 제9권3호
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• pp.274-281
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• 2007

In this paper, we present a hybrid multi-antenna technique that can minimize the outage probability by combining the diversity and beamforming techniques. The hybrid technique clusters the transmission antennas into multiple groups and exploit diversity among different groups and beamforming within each group. We analyze the performance of the resulting hybrid technique for an arbitrary correlation among the transmission antennas. Through the performance analysis, we derive a closed-form expression of the outage probability for the hybrid technique. This enables to optimize the antenna grouping for the given spatial correlation. We show through numerical results that the hybrid technique can balance the trade-offs between diversity and beamforming according to the spatial correlation and that the optimally designed hybrid technique yields a much lower outage probability than the diversity or beamforming technique does in partially correlated fading channels.

• Journal of Communications and Networks
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• 제10권4호
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• pp.444-450
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• 2008

This paper studies the performance of multiuser data networks with transmit diversity under correlated fading channels. Previous work shows that correlated fading reduces the link performance of multiple antenna systems, but how correlated fading affects the throughput of multiuser data networks is still unknown since the throughput depends not only on the link performance but also on the multiuser diversity. We derive the throughput of the multiuser data networks with various transmit diversity schemes under correlated fading channels. The impact of correlated fading on the throughput is investigated. Analytical and simulation results show that, although correlated fading is harmful for link performance, it increases the throughput of the multiuser data networks if the transmit scheme is appropriately selected.

• 농촌계획
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• 제28권3호
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• pp.73-82
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• 2022

Recently, social conflicts have intensified, and a diverse society is to the fore as a solution to social problems. In rural areas, the transition to a diverse society progressed due to population outflow, changes in the agricultural labor force, and an increase in multicultural families. In this study, regional social diversity in Gyeongsangnam province was measured using the neighborhood diversity index and the Simpson index. In addition, the relationship with the regional economy at the county level and township level was analyzed. As a result, it was found that the Gun regions have higher social diversity than the Si regions. and the city area showed a larger index value for residential segregation.

• Asian-Australasian Journal of Animal Sciences
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• 제25권9호
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• pp.1223-1228
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• 2012

The population sizes of three Korean indigenous cattle populations have been drastically reduced over the past decades. In this study, we examined the extent to which reduction in populations influenced genetic diversity, population structure and demographic history using complete mitochondrial DNA (mtDNA) control region sequences. The complete mtDNA control region was sequenced in 56 individuals from Korean Black (KB), Jeju Black (JEB) and Korean Brindle (BRI) cattle populations. We included 27 mtDNA sequences of Korean Brown (BRO) from the GenBank database. Haplotype diversity estimate for the total population was high (0.870) while nucleotide diversity was low (0.004). The KB showed considerably low nucleotide (${\pi}$ = 0.001) and haplotype (h = 0.368) diversities. Analysis of molecular variance revealed a low level of genetic differentiation but this was highly significant (p<0.001) among the cattle populations. Of the total genetic diversity, 7.6% was attributable to among cattle populations diversity and the rest (92.4%) to differences within populations. The mismatch distribution analysis and neutrality tests revealed that KB population was in genetic equilibrium or decline. Indeed, unless an appropriate breeding management practice is developed, inbreeding and genetic drift will further impoverish genetic diversity of these cattle populations. Rational breed development and conservation strategy is needed to safeguard these cattle population.

• 유기물자원화
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• 제13권2호
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• pp.85-90
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• 2005

산불로 훼손된 토양 미생물군집의 생화학적, 유전적 다양성을 비교하기 위하여 2000년에 산불이 일어났던 강릉지역에서 자연복원지 토양(NS), 인공복원지 토양(AS), 정상토양(NS)을 표토층과 심토층에서 채집하였다. 생화학적 다양성 분석을 위해 각 시료를 BIOLOG system에 직접 적용하였으며 통계처리(SPSS)를 통해 군집분석을 수행하였다. 또한 군집의 유전적 다양성은 토양 미생물의 16S-rDNA를 증폭하여 DGGE(Denaturing Gradient Gel Electrophoresis)를 이용하여 분석하였다. 자연복원지의 심토와 표토, 정상토양의 표토에서만 70% 이상의 생화학적 다양성이 나타났으나, 유전적 다양성의 경우 모든 시료에서 53%에서 68%의 범위의 상동성을 나타냈다. 이러한 결과는 토양미생물 군집의 생화학적 다양성이 반드시 유전적 다양성을 반영하지 않는다는 것을 보여준다.

• Asian-Australasian Journal of Animal Sciences
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• 제33권1호
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• pp.12-23
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• 2020

Objective: The objective of a conservation program is to maintain maximum genetic diversity and preserve the viability of a breed. However, the efficiency of a program is influenced by the ability to accurately measure and predict genetic diversity. Methods: To examine this question, we conducted a simulation in which common measures (i.e. heterozygosity) and novel measures (identity-by-descent probabilities and parental genomic components) were used to estimate genetic diversity within a conserved population using double-labeled single nucleotide polymorphism markers. Results: The results showed that the accuracy and sensitivity of identity-by-state probabilities and heterozygosity were close to identity by descent (IBD) probabilities, which reflect the true genetic diversity. Expected heterozygosity most closely aligned with IBD. All common measures suggested that practices used in the current Chinese pig conservation program result in a ~5% loss in genetic diversity every 10 generations. Parental genomic components were also analyzed to monitor real-time changes in genomic components for each male and female ancestor. The analysis showed that ~7.5% of male families and ~30% of female families were lost every 5 generations. After 50 generations of simulated conservation, 4 male families lost ~50% of their initial genomic components, and the genomic components for 24.8% of the female families were lost entirely. Conclusion: In summary, compared with the true genetic diversity value obtained using double-labeled markers, expected heterozygosity appears to be the optimal indicator. Parental genomic components analysis provides a more detailed picture of genetic diversity and can be used to guide conservation management practices.

• 한국환경복원기술학회지
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• 제18권3호
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• pp.65-77
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• 2015

The urban park has important functions as a habitat for wildlife as well as open space of rest and community for people. This study was carried out to find what factors of structure and vegetation of urban parks could affect forest bird species diversity in Cheonan city. The study surveyed bird and vegetation species in 26 urban parks, Cheonan city. A correlation analysis and multiple linear regressions were performed to test whether habitat structure and vegetation were the major correlate with species diversity. The results showed the Dujeong park was the most high bird species diversity (H' = 2.13), and the Dujeong-8 park (H' = 2.02) and the Cheongsa park (H' = 1.73) were considerably higher than the other urban parks. The variables that were strongly correlated with bird species diversity were park area, number of subtree species, canopy of shrub, number of shrub species, shape index, canopy of subtree, canopy of tree, and impervious surface ratio. The regression of bird species diversity against the environmental variables showed that 3 variables of park area, canopy of subtree, and canopy of tree were included in the best model. Model variable selection was broadly similar for the 5 optimal models. It means park area and multi-layer vegetation were the most consistent and significant predictor of bird species diversity, because urban parks were isolated by built-up areas. Especially the subtree coverage that provides shelter and food for forest birds was an important variable. Therefore, to make parks circular-shaped and abundant multi-layer vegetation, which could be a buffer to external disturbances and improve the quality of habitats, may be used to enhance species diversity in creation and management of urban parks.

• 한국해양생명과학회지
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• 제8권1호
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• pp.43-49
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• 2023

본 연구에서는 남극 로스해 연안에 서식하는 아델리펭귄(Pygoscelis adeliae)과 황제펭귄(Aptenodytes forsteri)의 분변 시료를 기반으로 펭귄 장내 미생물 메타지놈 연구를 수행하였다. Taxonomy 분석 결과, 아델리펭귄과 황제펭귄의 장내 미생물에는 주로 7개의 문(phylum), 18개의 과(family)가 존재하는 것으로 나타났다. 또한 미생물 다양성을 평가하기 위해 Alpha diversity 및 OTU abundance 분석을 수행한 결과, 전반적으로 아델리펭귄의 장내 미생물 다양성이 황제펭귄보다 높은 것을 확인하였고, PCoA를 기반으로 한 Beta diversity 분석을 통해 두 개체군 간 장내 미생물 군집에 차이가 존재함을 확인하였다. PICRUSt를 활용한 기능적인 차원의 KEGG pathway 분석을 통해서는 아델리펭귄과 황제펭귄 시료에서 nucleoside and nucleotide biosynthesis pathway가 가장 많이 존재하는 것을 확인하였다. 본 연구를 통해 남극 아델리펭귄과 황제펭귄의 장내미생물 구성과 다양성을 비교분석 할 수 있었다. 본 연구 결과는 향후 펭귄의 먹이 섭식 관련 연구에 활용될 수 있으며, 더 나아가 다양한 남극 생물의 장내미생물 메타지놈 분석에 대한 기초가 될 수 있을 것이다.

• The Plant Pathology Journal
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• 제30권1호
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• pp.10-24
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• 2014

Genetic diversity and differentiation of 50 Colletotrichum spp. isolates from legume crops studied through multigene loci, RAPD and ISSR analysis. DNA sequence comparisons by six genes (ITS, ACT, Tub2, CHS-1, GAPDH, and HIS3) verified species identity of C. truncatum, C. dematium and C. gloeosporiodes and identity C. capsici as a synonym of C. truncatum. Based on the matrix distance analysis of multigene sequences, the Colletotrichum species showed diverse degrees of intera and interspecific divergence (0.0 to 1.4%) and (15.5-19.9), respectively. A multilocus molecular phylogenetic analysis clustered Colletotrichum spp. isolates into 3 well-defined clades, representing three distinct species; C. truncatum, C. dematium and C. gloeosporioides. The ISSR and RAPD and cluster analysis exhibited a high degree of variability among different isolates and permitted the grouping of isolates of Colletotrichum spp. into three distinct clusters. Distinct populations of Colletotrichum spp. isolates were genetically in accordance with host specificity and inconsistent with geographical origins. The large population of C. truncatum showed greater amounts of genetic diversity than smaller populations of C. dematium and C. gloeosporioides species. Results of ISSR and RAPD markers were congruent, but the effective maker ratio and the number of private alleles were greater in ISSR markers.

• 한국치위생학회지
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• 제13권5호
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• pp.889-900
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• 2013

Objectives : Molecular biology techniques were employed to assess diversity of bacterial in children's dental caries. Methods : DNA of germs was extracted and the diversity of the 16S rRNA clones was analyzed by amplified rDNA restriction analysis and sequencing. The experimental samples were pit and fissure caries (PC), deep dentinal caries (DC), smooth surface caries (SC), and supragingival plaque (PQ) from 50 children of age less than 12 years old. The control group was healthy teeth supragingival plaque (HT). Thirty clones from each 16S rRNA clone library of 5 samples were randomly selected, thus a total of 150 clones were analyzed. Results : Amplified rDNA restriction analysis uncovered 18, 20, 11, 17, and 22 phylotypes from healthy teeth, pit and fissure caries, deep dentinal caries, smooth surface caries, and supragingival plaque, respectively. Sequencing analysis found the dominance of Actinomycs naeslundii and Fusobacterium nucleatum in the healthy teeth; Leptotrichia sp. in the pit and fissure caries; Actinomyces sp., Streptococcus mutans, and Rahnella aquatilis in the deep dentinal caries; Streptococcus mutans and Actinomyces sp. in the smooth surface caries; Enterobacter hormaechei and Streptococcus sanguinis in the supragingival plaque. Conclusions : Clonal analysis identified 6 phyla, 20 genera, and 51 species.