• Korean Journal of Plant Resources
• /
• v.20 no.6
• /
• pp.530-539
• /
• 2007

Genetic variation and structure of 9 subpopulations of Symplocarpus renifolius Schott ex Tzvelev on Mt. Cheonma, in Korea, were determined via starch-gel electrophoresis. The genetic diversity at 10 loci for 8 isozymes ($P_{99}=66%,\;A=2.26,\;H_o=0.212,\;H_e=0.230$) was found to be considerably higher than that seen in other long-lived perennial plants. On the whole, the genotype frequencies were in accordance with Hardy-Weinberg expectations. Approximately 5%($\theta=0.049$) of the total variability was among subpopulations. The high levels of observed genetic diversity in S. renifolius were attributed to a universal outcrossing system and other specific factors like differences in age classes and widely scattered individuals around the main distribution. Heterozygosity was highest at a mid-range of elevation($450m{\sim}600m$). The lowest heterozygosity at lower elevation was attributed to the possible origin of seeds transported by water from upstream regions during the monsoon season. Spatial structure in a subpopulation evidenced a strong autocorrelation between closer individuals within $3{\sim}4m$ of distance. This was assumed to be attributable to the restricted seed dispersal characteristics of S. renifolius. In accordance with the findings generated in this study, some implications regarding the conservation of S. renifolius at the Mt. Cheonma were also presented.

• ETRI Journal
• /
• v.30 no.3
• /
• pp.355-364
• /
• 2008

Multiple-input multiple-output (MIMO) systems can provide significant increments in capacity; however, the capacity of MIMO systems degrades severely when spatial correlation among multipath channels is present. This paper demonstrates that the influence of shadowing on the channel capacity is more substantial than that of multipath fading; therefore, the shadowing effect is actually the dominant impairment. To overcome the composite fading effects, we propose combining macroscopic selection diversity (MSD) schemes with MIMO technology. To analyze the system performance, the capacity outage expression of MIMO-based MSD (MSD-MIMO) systems using a characteristic function is applied. The analytic results show that there are significant improvements when MSD schemes are applied, even for the two-base-station diversity case. It is also observed that the effect of spatial correlation due to multipath fading is almost negligible when multiple base stations cooperatively participate in the mobile communication topology.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.12A
• /
• pp.1145-1151
• /
• 2010

Hochwald et al. introduced unitary space-time codes for quasi-static Rayleigh fading channels which allows for noncoherent decoding when the channel response is not known at the receiver. However, when reliable information on the channel response is available, coherent decoding is preferable for improved performance. Here, we study the relationship between the performance criteria on the diversity and coding advantages provided by unitary space-time codes with noncoherent and coherent decoding. We show that when a unitary space-time code achieves full spatial diversity with noncoherent decoding, full spatial diversity is also guaranteed with coherent decoding.

• Asian-Australasian Journal of Animal Sciences
• /
• v.28 no.6
• /
• pp.888-895
• /
• 2015

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and subsequent sub-cloning and sequencing were used in this study to analyze the molecular phylogenetic diversity and spatial distribution of bacterial communities in different spatial locations during the cooling stage of composted swine manure. Total microbial DNA was extracted, and bacterial near full-length 16S rRNA genes were subsequently amplified, cloned, RFLP-screened, and sequenced. A total of 420 positive clones were classified by RFLP and near-full-length 16S rDNA sequences. Approximately 48 operational taxonomic units (OTUs) were found among 139 positive clones from the superstratum sample; 26 among 149 were from the middle-level sample and 35 among 132 were from the substrate sample. Thermobifida fusca was common in the superstratum layer of the pile. Some Bacillus spp. were remarkable in the middle-level layer, and Clostridium sp. was dominant in the substrate layer. Among 109 OTUs, 99 displayed homology with those in the GenBank database. Ten OTUs were not closely related to any known species. The superstratum sample had the highest microbial diversity, and different and distinct bacterial communities were detected in the three different layers. This study demonstrated the spatial characteristics of the microbial community distribution in the cooling stage of swine manure compost.

• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• v.2 no.2
• /
• pp.120-128
• /
• 2021

The objective of this study was to analyze the genotype of black-spotted pond frog (Pelophylax nigromaculatus) using seven microsatellite loci to quantify its genetic diversity and population structure throughout the spatial scale of basins of Han, Geum, Yeongsan, and Nakdong Rivers in South Korea. Genetic diversities in these four areas were compared using diversity index and inbreeding coefficient obtained from the number and frequency of alleles as well as heterozygosity. Additionally, the population structure was confirmed with population differentiation, Nei's genetic distance, multivariate analysis, and Bayesian clustering analysis. Interestingly, a negative genetic diversity pattern was observed in the Han River basin, indicating possible recent habitat disturbances or population declines. In contrast, a positive genetic diversity pattern was found for the population in the Nakdong River basin that had remained the most stable. Results of population structure suggested that populations of black-spotted pond frogs distributed in these four river basins were genetically independent. In particular, the population of the Nakdong River basin had the greatest genetic distance, indicating that it might have originated from an independent population. These results support the use of genetics in addition to designations strictly based on geographic stream areas to define the spatial scale of populations for management and conservation practices.

• Journal of electromagnetic engineering and science
• /
• v.6 no.4
• /
• pp.222-228
• /
• 2006

In this paper, the performance of a multiuser diversity system combined with a multi-element transmit antenna system is analyzed under the assumption of independent Rayleigh fading. A measure of system .level performance is an average channel capacity as a function of the number of users and antennas. Average channel capacity is obtained from the instantaneous signal-to-noise ratio(SNR) distribution combined by both transmit diversity(TD) at each link and multiuser diversity at system level. Numerical results show that closed-loop antenna techniques provide an additional gain with multiuser diversity system due to array gain, even though space diversity gain reduces multiuser diversity gain. On the other hand, the space-time block coding(STBC) that provides full order space diversity gain only has a destructive influence on multiuser diversity.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2006.11a
• /
• pp.201-204
• /
• 2006

In this paper, we propose efficient scheduling strategy for Multi-user MIMO systems that find advantageous trade off solution between multiuser diversity and spatial diversity, spatial multiplexing technique. Specifically, we suggest P-SFS(Pseudo-SNR Fair scheduling) algorithm that consider throughput and fairness problem. also we propose channel aware Antenna deployment that decide how to use assigned multiple antennas by the information of each user's channel condition.

• Journal of Environmental Science International
• /
• v.20 no.2
• /
• pp.155-161
• /
• 2011

In application and discussion of population structure and phenotypic divergence in plant community, the classic Lotka-Volterra models of competition and spatial model are conceived as a mechanism that is composed by multiple interacting processes. Both the Lotka-Volterra and spatial simulation formulae predict that species diversity increases with genotypic richness (GR). The two formulae are also in agreement that species diversity generally decreases within increasing niche breadth (NB) and increases with increasing potential genotypic range (PGR). Across the entire parameter space in the Lotka-Volterra model and most of the parameter space in the spatial simulations, variance in community composition decreased with increasing genotypic richness. This was, in large part, a consequence of selecting genotypes randomly from a set pool.

• Journal of Advanced Navigation Technology
• /
• v.14 no.2
• /
• pp.220-226
• /
• 2010

In this paper, an low power symbol detector is proposed for MIMO communication system with two transmit and two receive antennas. The proposed symbol detector can support both the spatial multiplexing (SM) mode and spatial diversity (SD) mode for MIMO transmission technique, and shows the optimal maximum likelihood (ML) performance. Also, by sharing the hardware block and using the dedicated clock MIMO modes, the power of the proposed architecture is dramatically decreased. The proposed symbol detector was designed in hardware description language (HDL) and synthesized to logic gates using a $0.13-{\mu}m$ CMOS standard cell library. The power consumption was estimated by using Synopsys Power CompilerTM, which is reduced by maximum 85%, compared with the conventional architecture.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.9
• /
• pp.1517-1526
• /
• 2018

Investigating bacterial diversity and its metabolic capabilities is crucial for interpreting the ecological patterns in a desert environment and assessing the presence of exploitable microbial resources. In this study, we evaluated the spatial heterogeneity of physicochemical parameters, soil bacterial diversity and metabolic adaptation at meter scale. Soil samples were collected from two quadrats of a desert (Thar Desert, India) with a hot, arid climate, very little rainfall and extreme temperatures. Analysis of physico-chemical parameters and subsequent variance analysis (p-values < 0.05) revealed that sulfate, potassium and magnesium ions were the most variable between the quadrats. Microbial diversity of the two quadrats was studied using Illumina bar-coded sequencing by targeting V3-V4 regions of 16S rDNA. As for the results, 702504 high-quality sequence reads, assigned to 173 operational taxonomic units (OTUs) at species level, were examined. The most abundant phyla in both quadrats were Actinobacteria (38.72%), Proteobacteria (32.94%), and Acidobacteria (9.24%). At genus level, Gaiella represented highest prevalence, followed by Streptomyces, Solirubrobacter, Aciditerrimonas, Geminicoccus, Geodermatophilus, Microvirga, and Rubrobacter. Between the quadrats, significant difference (p-values < 0.05) was found in the abundance of Aciditerrimonas, Geodermatophilus, Geminicoccus, Ilumatobacter, Marmoricola, Nakamurella, and Solirubrobacter. Metabolic functional mapping revealed diverse biological activities, and was significantly correlated with physicochemical parameters. The results revealed spatial variation of ions, microbial abundance and functional attributes in the studied quadrats, and patchy nature in local scale. Interestingly, abundance of the biotechnologically important phylum Actinobacteria, with large proposition of unclassified species in the desert, suggested that this arid environment is a promising site for bioprospection.