• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8A
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• pp.1156-1162
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• 1999

In this paper, the problem of decoding transmitted data sequence with diversity reception in the presence of nondelective fading is studied. The expection maximizaton (EM) algorithm is employed to derive an interactive algorithm. The algorithm performs block-by-block coherent decoding with the aid of pilot symbols. It is shown that the complexity of the algorithm grows linearly as a function of sequence length. The performance of the algorithm is shown to better than that of the conventional pilot symbol aided (PSI) algorithm. Simulation results are presented to assess the performance of the algorithm and the results are compared with that of the conventional PSI alforithm.

• The Korean Journal of Mycology
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• v.49 no.1
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• pp.11-19
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• 2021

In 2017, Talaromyces variabilis was isolated during a survey of fungal diversity in field soils in Korea. This isolate was described based on its morphological and molecular characteristics and it was identified molecularly using the partial 18S-ITS1-5.8S-ITS2-28S rDNA region and calmodulin (CaM)-encoding gene sequence data. Thus, this study reported morphological and multigene sequence characterization of T. variabilis.

• Fisheries and Aquatic Sciences
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• v.14 no.1
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• pp.16-21
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• 2011

The genetic diversity and population genetic structure of thread-sail filefish, Stephanolepis cirrhifer (Temminck & Schlegel), were examined with a nucleotide sequence analysis of a 495bp fragment of the 5'-end of the cytochrome b gene in 113 fish collected from five populations from the south and east coasts of the Korean Peninsula. Seventeen variable nucleotide sites and 16 haplotypes were defined. The observed haplotypes had a shallow haplotype genealogy and no geographical association. Most of the populations had high haplotype diversity and low nucleotide diversity, and significant negative values for Fu's $F_S$, suggesting rapid, recent population growth from an ancestral population and sudden population expansion. The estimated pairwise fixation indices ($F_{ST}$) indicate that substantial gene flow occurs among these populations. Thread-sail filefish in the South Sea of Korea and East Sea Korean populations forms a single panmictic population. Thus, thread-sail filefish in these areas should be treated as one management unit.

• Korean Journal of Oriental Medicine
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• v.14 no.3
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• pp.49-56
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• 2008

Glehnia littoralis Fr. Schmidt et Miquel is an important medicinal plants in East Asian countries. This plant species naturally distributed in Korea, Japan, China, and Taiwan, but it is a rare plants living in the coastal dune in Korea. To investigate the genetic variation, genetic diversity and genetic evolutionary relationships of 14 different geographical G. littoralis, ITS sequence and random amplified polymorphic DNA (RAPD) were analyzed. On the basis of ITS sequences, it was clearly showed that the ITS1 and ITS2 sequences among 14 populations are identical regardless of geographical origin excepting 2 bp in pair-wise comparison of ITS1. Furthermore, RAPD results also showed that 14 different geographical G. littoralis produce various polymorphic patterns without critical relationship among neighboring regions. These combined results suggest that the geographical variation and genetic evolution of G. littoralis is stable and provide important information on genetic diversity, and conservation of this rare plant species in situ and ex situ.

• Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.243-251
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• 2013

Genetic diversity and gene flow patterns in Pollicipes mitella were investigated with a nucleotide sequence analysis of 514 base pairs from the mitochondrial cytochrome c oxidase subunit I gene (COI) in 124 samples collected from six Korean populations. In total, 59 haplotypes were defined by 40 variable nucleotide sites in the COI region. The haplotypes had shallow haplotype genealogy and no geographic associations. All populations had high haplotype diversity (0.909 to 0.979) and low nucleotide diversity (0.0055 to 0.0098). The haplotypes with recently diverged nucleotides were distributed by long-range larvae dispersal among regional populations. The pairwise fixation indices ($F_{ST}$) estimated with the exact test and migration rates indicate that substantial gene flow has occurred among populations as a result of sea currents, except between the Uljin (East Sea coast) and other Korean populations. This suggests that significant genetic differentiation and low migration rates have affected the Uljin population.

• Journal of Communications and Networks
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• v.15 no.3
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• pp.276-282
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• 2013

Self-encoded spread spectrum (SESS) is a novel modulation technique that acquires its spreading code from a random information source, rather than using the traditional pseudo-random noise (PN) codes. In this paper, we present our study of the SESS system performance under pulsed-noise jamming and show that iterative detection can significantly improve the bit error rate (BER) performance. The jamming performance of the SESS with correlation detection is verified to be similar to that of the conventional direct sequence spread spectrum (DSSS) system. On the other hand, the time diversity detection of the SESS can completely mitigate the effect of jamming by exploiting the inherent temporal diversity of the SESS system. Furthermore, iterative detection with multiple iterations can not only eliminate the jamming completely but also achieve a gain of approximately 1 dB at $10^{-3}$ BER as compared with the binary phase shift keying (BPSK) system under additive white gaussian noise (AWGN) by effectively combining the correlation and time diversity detections.

• Journal of Plant Biotechnology
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• v.44 no.3
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• pp.312-319
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• 2017

The need to preserve and use plant genetic resources is widely recognized, and the prospect of dwindling plant genetic diversity, coupled with increased demands on these resources, has made them a topic of global discussion. In the present study, the genetic diversity and population structure of 73 ginseng accessions collected from six regions in China were analyzed using eight simple sequence repeat (SSR) markers. Major allele frequencies ranged between 0.38 ~ 0.78, with a mean allele frequency value of 0.571. The number of alleles discovered ranged from 3 to 10 per accession, with a mean number of 7; 56 alleles were discovered in total. Gene diversity (GD) and polymorphic information content (PIC) values were similar to each other, and they ranged from 0.36 ~ 0.77 (mean 0.588) and 0.33 ~ 0.74 (mean 0.548), respectively. Accessions were divided into three clusters based on their phylogenetic relationships and genetic similarities, and although the populations were similar, they were not classified according to the region. Regional genetic diversity was also similar, with slight differences observed based on the number of accessions per region. It is expected that the findings of the present study can provide basic data for future studies on ginseng genetic diversity and for breeding ginseng cultivars.

• Korean Journal of Medicinal Crop Science
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• v.24 no.4
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• pp.317-322
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• 2016

Background: In the herbal medicine market, Angelica gigas, Angelica sinensis, and Angelica acutiloba are all called "Danggui" and used confusingly. We aimed to assess the genetic diversity and relationships among 14 Angelica species collected from different global seed companies. Toward this aim we developed DNA markers to differentiate the Angelica species. Methods and Results: A total of 14 Angelica species, A. gigas, A. acutiloba, A. sinensis, A. pachycarpa, A. hendersonii, A. arguta, A. keiskei, A. atropurpurea, A. dahurica, A. genuflexa, A. tenuissima, A. archangelica, A. taiwaniana, and A. hispanica were collected. The genetic diversity of all 14 species was analyzed by using five chloroplast DNA-based simple sequence repeat (SSR) markers and employing the DNA fragment analysis method. Each primer amplified 3 - 12 bands, with an average of 6.6 bands. Based on the genetic diversity analysis, these species were classified into specific species groups. The cluster dendrogram showed that the similarity coefficients ranged from 0.77 to 1.00. Conclusions: These findings could be used for further research on cultivar development by using molecular breeding techniques and for conservation of the genetic diversity of Angelica species. The analysis of polymorphic SSRs could provide an important experimental tool for examining a range of issues in plant genetics.

• International Journal of Industrial Entomology and Biomaterials
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• v.22 no.2
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• pp.65-74
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• 2011

The Scarites aterrimus (Coleoptera: Carabidae), is one of the carabid beetles dwelling exclusively on coastal sandy dunes. Habitat deterioration and equivalent activity have greatly concerned population declines in several species dwelling on the coastal sandy dunes. As a first step to establish long-term conservation strategy, we investigated the nation-wide magnitude and nature of genetic diversity of the species. As a first step, we sequenced a portion of mitochondrial COI gene, corresponding to "DNA Barcode" region (658 bp) from a total of 24 S. aterrimus individuals collected over nine sandy dunes belonging to four Korean provinces. The sequence analysis evidenced moderate to low magnitude of sequence diversity compared with other insect species distributed in Korean peninsula (0.152% to 0.912%). The presence of closely related haplotypes and relatively high gene flow estimate collectively suggest that there had been no historical barriers that bolster genetic subdivision. Population decline was postulated on the basis of several missing haplotypes that are well found in the species with a large population size. This interpretation is consistent with field observation of small population size in the coastal sandy dune habitats. The highest genetic diversity estimates were found in the coastal sand dune population of Seogwipo, Jeju Island, justifying a prior attention to the population, in order to sustain overall genetic diversity of the species. Further scrutinized study might be required for further robust conclusion.

• Journal of Plant Biotechnology
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• v.46 no.3
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• pp.158-164
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• 2019

Molecular characterization of different genotypes reveals accurate information about the degree of genetic diversity that helps to develop a proper breeding program. In this study, a total of 30 EST-based simple sequence repeat (EST-SSR) markers derived from trumpet lily (Lilium longiflorum) were used across 11 native lily species for their genetic relationship. Among these 30 markers, 24 SSR markers that showed polymorphism were used for evaluation of diversity spectrum. The allelic number at per locus ranged from 1 at SSR2 locus to 34 alleles at SSR15 locus, with an average of 11.25 alleles across 24 loci observed. The polymorphic information content, PIC, values ranged from 0.0523 for SSR9 to 0.9919 for SSR2 in all 24 loci with an average of 0.3827. The allelic frequency at every locus ranged from 0.81% at SSR2 locus to 99.6% at SSR14 locus. The pairwise genetic dissimilarity coefficient revealed the highest genetic distance with a value of 81.7% was in between L. dauricum and L. amabile. A relatively closer genetic distance was found between L. lancifolium and L. dauricum, L. maximowiczii and L. concolor, L. maximowiczii and L. distichum (Jeju), L. tsingtauense and L. callosum, L. cernuum and L. distichum (Jeju ecotype), of which dissimilarity coefficient was 50.0%. The molecular fingerprinting based on microsatellite marker could serve boldly to recognize genetically distant accessions and to sort morphologically close as well as duplicate accessions.