• Journal of information and communication convergence engineering
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• v.9 no.5
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• pp.515-522
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• 2011

In this paper, we investigate cooperative diversity in a spectrum sharing environment where secondary users utilize primary users' spectrum only if the interference power received at the primary users is maintained below a predetermined level. The outage probability of a selective decode-and-forward (DF) based cooperative diversity scheme in the secondary network is derived to analyze the effects of spectrum sharing on cooperative diversity. Our analytical and simulation results show that the outage probability is saturated at a certain level of transmit power of secondary users due to interference regulation, and, hence, cooperative diversity gains are lost. Through asymptotic analysis, we also identify the critical value of transmit SNR beyond which the outage probability is saturated.

• Asia pacific journal of information systems
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• v.15 no.2
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• pp.149-170
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• 2005

This study assessed diversity in MIS research by examining 357 articles published in Journal of MIS Research from 1991 to 2003. The classification system developed by Vessey et al.(2002) was employed to examine research diversity of the articles. The classification system comprises four key characteristics of diversity such as research topic, research method, level of analysis, and reference discipline. The results of our study were also compared with Vessey et al,(2002)'s results to address problems in current MIS research and to suggest some recommendations for the future MIS research in Korea.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2004.11a
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• pp.169-175
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• 2004

Considering the present development situation of domestic apartment complexes, the environment and its landscape is monotonous and dull, so the diversity is very important socially and visually. The ground floor dwellings can influence the richness and diversity of ground landscape in the apartment housing. Because they are set on the ground and directly contact with people's sight line. In this context, this study aims to identify the elements of design diversity in the ground floor dwellings, to analysis the architectural characteristics of them and to propose the improvement of diversity.

• Journal of Communications and Networks
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• v.9 no.3
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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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• v.10 no.4
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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.

• Journal of Korean Society of Rural Planning
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• v.28 no.3
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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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• v.25 no.9
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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.

• Journal of the Korea Organic Resources Recycling Association
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• v.13 no.2
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• pp.85-90
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• 2005

Changes of biochemical and genetic diversity of microbial communities in the soil damaged by a forest fire were analyzed. Soil samples were collected from Gangnung area where a forest fire was broken out in 2000. Two soil samples were from the burnt area, one from the naturally restoring soil (NS) and the other from the artificially restoring soil (AS). A normal, unaffected soil sample (US) was also included as a control. For the biochemical diversity, each sample was directly applied to the BIOLOG system, and the cluster analysis through a statistic process (SPSS) were performed. Genetic diversity was analyzed through DGGE using 16S-rDNA amplified from soil DNA. Among the samples tested, top soils of US and NS, and sub soil of NS revealed more than 70% of the similarity value in biochemical diversity. In case of genetic diversity, however, the similarity value was found to be in the range of 53% to 68% in all samples. This result indicates that the biochemical diversity is not always correlated with the genetic diversity in the analysis of microbial communities.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.1
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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.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.3
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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.