• Mycobiology
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• v.49 no.5
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• pp.454-460
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• 2021

Daecheongdo and Socheongdo Islands are located in the West Sea of Korea, 210 km away from land, and are military border areas very close to North Korea, making them difficult to access. Although the ecosystem of the islands is relatively well preserved due to the lack of accessibility, research on fungi of the regions is insufficient. Therefore, we aimed to investigate indigenous fungi in these geographically and geopolitically constrained regions. A survey of the indigenous fungal diversity of the islands was conducted in 2018. All specimens were identified at the species level based on morphological and molecular analyses. Among them, six macrofungi-namely, Agaricus menieri, Crepidotus praecipuus, Dichomitus squalens, Hortiboletus amygdalinus, Melanoleuca friesii, and Trametes lactinea-were not previously reported in Korea. Considering that the proportion of unrecorded species is high in the survey area and period as well as the number of samples collected, similar research on adjacent islands may be necessary.

• Korean Journal of Plant Taxonomy
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• v.50 no.4
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• pp.419-426
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• 2020

A total of 34 taxa, 33 species and one variety, are newly added to the moss checklist of Korea. They were collected on Jejudo Island, Samcheok limestone areas in Gangwon Province, and Socheongdo Island from 2015 to 2018 and organized into 19 families and 26 genera. Additionally, eight genera are new to Korea. This study verifies the distributions of nine species whose distributions and specimens have remained unknown thus far. Finally, two unrecorded taxa, consisting of one species and one variety, are identified by reexamining Korean specimens deposited at the National Museum and Science in Japan (TNS). The specimens were collected in 1942 and 1940 from Mt. Baekdusan and Anbyun in North Korea.

• Korean Journal of Plant Resources
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• v.29 no.4
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• pp.434-466
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• 2016

In order to illustrate the flora of vascular plants distributed in the Five West Sea Islands, the authors collected vascular plants intensively in Baengnyeongdo and Socheongdo from May 2015 to August 2015. Also, voucher specimens from the previous investigations (Daecheongdo, Yeonpyeongdo and Soyeonpyeongdo) deposited at the Korean National Arboretum (KH) were re-identified. All of them were comprised of 108 families, 420 genera, 728 species, 6 subspecies, 86 varieties and 14 forms, totally 834 taxa. There were 8 endemic taxa, 19 rare taxa, 27 taxa for floristically specific to Korean floral zone except the species of their 1st and 2nd degree, and 107 naturalized taxa among the collected plants. Owing to their unusual phytogeography and low number of populations, the taxa Rosa maximowicziana Regel, Allium anisopodium Ledeb., Bistorta pacifica (Petrov ex Kom.) Kom., Scorzonera austriaca subsp. glabra (Rupr.) Lipsch. & Krasch. ex Lipsch., Iris dichotoma Pall., Amsonia elliptica (Thunb.) Roem. & Schult. were considered the most important. Based on these results, it is clear that appropriate plants to conserve the natural habitat of the Five West Sea Islands must be made immediately.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.4
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• pp.245-250
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• 2022

As location-based services using the Global Navigation Satellite System (GNSS) are diversified, concerns about the vulnerability of GNSS to radio disturbance and deception are also growing. Accordingly, countries that own and operate GNSS, such as the United States, Russia, and Europe, are also developing additional navigation systems that can compensate for GNSS' weaknesses. Among them, an R-Mode system that transmits navigation signals using an infrastructure that transmits differential GNSS (DGNSS) information using signals from the medium frequency band currently in operation is being developed in Europe and Korea. Since 2020, Korea has improved four DGNSS transmission stations, including Chungju, Eocheongdo, Palmido, and Socheongdo, to transmit R-Mode signals and test navigation performance in some parts of the West Sea. In this paper, we intend to establish a testbed for measuring the distance of R-Mode signals currently being transmitted and analyze the results. It is confirmed that the distance measurement performance varies depending on the antenna type, diurnal variation, and propagation path of the signal.

• Microbiology and Biotechnology Letters
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• v.39 no.3
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• pp.210-217
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• 2011

In an effort to isolate novel bacteria for the bioremediation of over-fertilized soils, we identified 135 denitrifying cells out of 3,471 oligotrophic bacteria pools (3.9%) using a denitrification medium supplemented with potassium nitrate as the sole nitrogen source. Soil samples were taken from ecologically well-conserved areas, including a mountain swamp around the demilitarized zone (Yongneup), two ecoparks (Upo and the Mujechi bog), and ten representative islands around the Korean peninsula (Jejudo, Daecheongdo, Socheongdo, Baekryeongdo, Ulrungdo, Dokdo, Geomundo, Hongdo, Huksando and Yeonpyeongdo). All of the 135 bacteria produced nitrogen gas from the denitrification medium, and were proved to be nitrate reductase positive by API-BioLog tests. Phylogenetic analysis using 16S rDNA sequences revealed that the 135 bacteria consisted of 44 different genera. Along with the most prominent, Proteobacteria (87.4%), we identified denitrifying bacteria from Firmicutes (9.4%), Actinobacteria (2.4%), and Bacteroidetes (0.8%). Physiological analyses of the 44 representative denitrifying bacteria, under various pH levels, growth temperatures and salt stresses, revealed 12 favorable denitrifying strains for soil bioremediation.