• Journal of Species Research
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• v.6 no.spc
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• pp.129-134
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• 2017

This study aims to investigate the freshwater bryozoans of Jeju Island off the Korean Peninsula for the first time. To date, twelve species has been reported from the mainland of Korea. However, no study of freshwater bryozoans has ever been conducted on Korean islands including Jeju Island, which is the largest island in Korea. Five species in three genera Fredericella, Plumatella and Stephanella, from Jeju Island are described. Of which, three species, Fredericella indica, Plumatella mukaii and P. rugosa, are new records of Korean bryozoan fauna. As a result of this study, the number of identified Korean freshwater bryozoans is now 15 species, including 12 phylactolaemates and three gymnolaemates.

• Korean Journal of Environmental Biology
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• v.33 no.4
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• pp.390-393
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• 2015

Some asteroid specimens were collected at a depth of 150 m near Moseulpo in Jeju Island, Korea using fishing nets on October 2014. The specimens were identified as Henricia pacifica Hayashi, 1940 belonging to the family Echinasteridae of order Spinulosida. In the Korean fauna, seven species of genus Henricia were reported of which two species, H. nipponica and H. ohshimai, were distributed in Jeju Island. The morphological characteristics of this species were re-described with illustrations.

• Journal of Species Research
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• v.1 no.2
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• pp.249-256
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• 2012

Located 60 km from southern tip of Korean peninsula, Jeju is the largest Island in Korea and composed of volcanic habitat. Twenty-eight species of terrestrial mammals are listed from Jeju Island, of which 1 species and 3 subspecies are endemic. Also, 1 endangered species and 4 invasive alien species of land mammals are listed. Current status, brief history, management and conservation of the 28 species are discussed.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.47-55
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• 2015

This paper proposes the installation of a new modular multilevel converter based high-voltage direct current (MMC-HVDC) system to connect between mainland and Jeju island power systems in Korea in 2020. The purpose is to combine with two old line-commutated converters (LCC)-based HVDC system to achieve a stability of the Jeju island power system. The operation of the overall system will be analyzed in three cases: (i) wind speed is variable, (ii) either one of the LCC-HVDC systems is shutdown because of a fault or overhaul, (iii) a short circuit fault occurs at the mainland side. The effectiveness of the proposed control method is confirmed by the simulation results based on a PSCAD/EMTDC simulation program.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.21 no.2
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• pp.127-133
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• 2018

Purpose: For 3 consecutive years from 2012-2014, we analyzed the causative factors for why the Jeju Island had the highest obesity prevalences of school children among the 15 provinces in Korea. Methods: From our analysis of 28,026 elementary school children with obesity or normal weight in the 15 provinces, we analyzed 12 factors related to eating habits, exercise habits, lifestyle, and mental health. The differences between the obese and normal weight children were researched. Finally, Jeju was compared with Seoul, which has the lowest obesity prevalence in school age children. Statistical analysis was performed using the chi square test of PASW Statistics ver. 18.0. Results: Compared to the normal weight group, the obese group had significantly higher rates of consuming soft drinks (p<0.001), fast food intake (p=0.019), skipping breakfast (p<0.001), insufficient sleep (p<0.001), bullying experiences (p=0.001) and runaway impulses (p=0.012). Compared to Seoul, Jeju Island had significantly higher rates of Ramen intake (3.4% vs. 5.4%, p=0.021) and meat intake (46.0% vs. 52.9%, p=0.003). On the other hand, Jeju Island was significantly lower than was Seoul in their fruit intake (83.4% vs. 67.1%, p<0.001), vegetable intake (71.4% vs. 64.2%, p=0.001), and intense physical activity (63.4% vs. 47.7%, p<0.001). Meanwhile, insufficient sleep (15.4% vs. 9.6%, p<0.001) and runaway impulses (5.6% vs. 3.3%, p=0.027) in children were significantly lower in Jeju Island than in Seoul. Conclusion: The results of the obesity factor analysis of elementary school students in Jeju Island can be used as useful educational material for lowering the obesity prevalence in Jeju community.

• Fisheries and Aquatic Sciences
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• v.11 no.3
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• pp.166-171
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• 2008

The feasibility of photo-identification techniques for the bottlenose dolphins from Jeju Island, Korea, and the potential for dolphin watching were simultaneously evaluated in this study. During the sighting survey, a pod of bottlenose dolphins composed of approximately 30 individuals was observed in the southwestern coastal area of Jeju Island. Among 35 suitable photographs, five bottlenose dolphin individuals were identified and cataloged using unique nicks and notches on their dorsal fins. This shows that the Jeju Island dolphins can be individually identified by the nicks and notches on their dorsal fins using photo-identification techniques. Furthermore, the Jeju Island population appears to be suitable for long-term population biology studies using this technique. The potential for dolphin watching around the island would be higher if more information on the seasonal distribution, movement, and residency of this population were obtained.

• Journal of Korean Society of Rural Planning
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• v.24 no.3
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• pp.43-54
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• 2018

The residential population of Jeju Island has increased more than 10% for last 10 years. Especially, the tourist population is more than twice comparing to 2005. The population growth of Jeju has brought about large-scale urban development and increased land demands for tourism services. The goal of this study is to analyze the human, social, and environmental status of Jeju Island and to evaluate the environmental capacity of land use using ecological footprint (EF) model. This study shows the changes in ecological deficits of Jeju Island through estimating ecological productive land (EPL) considering EF from 2005 to 2015. The categories of total EF consists of food land, built-up land, forestry, and energy consumption. In order to reflect the characteristics of resort island, we consider not only residential population but also tourist population who can increase land demands. The outputs of this study also provide the potential excess demands of EPL and suggest needs of sustainable management plans for the limited land of Jeju Island.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.6
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• pp.494-502
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• 2014

This paper presents a control method of the modular multilevel converter - high-voltage direct current (MMC-HVDC) system to regulate grid voltage on the basis of the Jeju Island power system. In this case, the MMC-HVDC system is controlled as a static synchronous compensator (Statcom) to exchange the reactive power with the power grid. The operation of the MMC-HVDC system is verified by using the PSCAD/EMTDC simulation program. The Jeju Island power system is first established on the basis of the parameters and measured data from the real Jeju Island power system. This power system consists of two line-commutated converter - high-voltage direct current (LCC-HVDC) systems, two Statcom systems, wind farms, thermal power plants, transformers, and transmission and distribution lines. The proposed control method is then applied by replacing one LCC-HVDC system with a MMC-HVDC system. Simulation results with and without using the MMC-HVDC system are compared to evaluate the effectiveness of the control method.

• Journal of the Korean earth science society
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• v.26 no.2
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• pp.109-113
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• 2005

In this study, the estimation of the temperature distribution of Jeju Island with coastal ocean derived from the thermal band of Landsat 7/ETM+ of January 6, 2003 was carried out. For the computation of the temperature of the island and the coastal ocean based on the thermal band, we used NASA method wiich is the 8 bit Digital Number(DN) converted into spectral radiance. The computed results showed that the land temperature variations were from 0 to 12 Celsius degrees, and a good agreement with the observation ones based on the method. However, the ocean surface temperature was not much changed ground 15 degree since the water was well mixed between the coastal and the offshore ocean. The interesting results were that the temperature distributions of the southern part(Seogwipo City) of Jeju Island were higher than those of the north one(Jeju City) by more than 2 Celsius degree at the same height although the distance between the Jeju and the Seogwipo is only about 35km in winter season. The reason was found that the solar irradiance intensity of the south part was stronger than the north one by Halla mountain in winter season only. From the results, we found that the seasonal variations of solar irradiation and the height of Mt. Halla were an important role of temperature distribution of Jeju Island.

• Journal of Environmental Science International
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• v.23 no.12
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• pp.2057-2069
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• 2014

This study was carried out to estimate the BVOCs emissions with the emission factors which reflected the native conditions of forests in Jeju Island. This study made effective use of the previous data for the weather data and the emission rate of each organic volatile component measured at 10 species of conifers and broad leaved trees. The CORINAIR method and the grid system of $1km{\times}1km$ for whole area of Jeju Island were adopted in calculating the BVOCs emission emitted from forest. The vegetation information for Jeju Island was referred to GIS and a government report. By the results of BVOCs emission for Jeju Island, the 85% of monoterpene emission was emitted from conifers and the others was from broad leaved trees. Most of monoterpene emission was attributed to Pinus thunbergii and Cryptomeria japonica. The broad leaved trees greatly contributed to the isoprene emission and Quercus serrata played a dominant role in emission of isoprene. The total amount of BVOCs emission was estimated as $3612ton\;yr^{-1}$ in Jeju Island. The 51.1% of total emission was contributed to conifers, the 44.9% to broad leaved trees, and the 4.0% to grassland. Of total emission of BVOCs, monoterpene accounted for 32.3%, isoprene for 28.0%, and OVOCs for 39.7%. The BVOCs emission estimated by this study was less than that estimated by other previous study. This means that it is important to survey the emission rate at native conditions and gather the detailed information for various species of vegetation on target region.