• Journal of Ocean Engineering and Technology
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• v.31 no.4
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• pp.308-314
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• 2017

The purpose of this study was to investigate the sea floor using a seismic profiler in the northern part of Chagwi-do of Jeju Island in order to select the optimal location for the 60-m-class berth of a sea test bed for wave energy converters and provide basic environmental data for designing a suction anchor. The echo types of the seismic profiles were classified based on the study of Kim et al. (2016a), and the location for installing the suction anchor was selected based on a sediment thickness of more than 10 m. The physical properties of the surface sediments were determined by analyzing the sediment samples obtained from 16 grab sample points. Based on the investigation and analysis, we proposed a survey area in the North-Eastern sea as an optimum location for the 60-m-class berth where the suction anchor could be installed.

• Animal Systematics, Evolution and Diversity
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• v.33 no.1
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• pp.8-16
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• 2017

We firstly described a box jellyfish, Carybdea brevipedalia collected from the southern coasts of Korea. It is morphologically characterized by gastric phacellae, a special digestive system of cubozoan jellyfish, and velarium, the thin muscle flap forming the opening of the subumbrellar cavity. The phacellae are linear-shaped, comprising numerous cirri branched from multiple roots. Each root also has multiple numbers of cirrus bundles. Basis of velarial cannels parts into two branches in each octant of velarium. Its geographic distributions were limited to Jeju-do and the middle-southern coasts where the organisms are seriously hazardous to bathers in summer. Numerous individuals and/or large-sized populations were observed specifically from beaches at Jeju-do, Namhae-do and a small fishing port of Namildae, while only a small amount of the individuals was observed in Gamak Bay, Jaran-Goseung Bay, and Geoje-do. We confirmed molecular identity of the Korean C. brevipedalia with comparison of nuclear ribosomal DNA sequences. Until now, Carybdea brevipedalia is the only cubozoan species reported to be distributed in Korean waters.

• ALGAE
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• v.34 no.2
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• pp.177-185
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• 2019

Ecklonia cava is popular in Korea as a marine functional materials. E. cava is generally collected and used on the coast of Jeju Island. However, the continuous use of collected natural E. cava may be limited because difficult to secure throughout the year and may be exposed to environmental pollution. Jeju magma seawater (MSW) was known to be significant advantages such as safety, cleanness, stability, and functional improvement. Attempts have been reported on application of MSW to the culturing of macro- and microalgae and showed improved results. Thus, the objective of the present study was to explore the anti-melanogenesis activity of brown seaweed E. cava (E. cava cultured with MSW [MSWE]) extract cultured in tanks with MSW of Jeju Island to evaluate the possibility of cosmeceutical industrial application. MSWE extract showed the higher polyphenolic and dieckol contents than natural E. cava (NE) extract. Anti-melanogenesis activity of MSWE extract and NE extract are tested and compared using tyrosinase and dihydroxyphenylalanine (DOPA) oxidation inhibition assay. MSWE extracts evidenced more effective tyrosinase and DOPA oxidation inhibition activity than that of the NE extracts and the commercial whitening agent, arbutin. MSWE extracts also markedly inhibited melanin synthesis and decreased the expression of melanogenesis-related protein in ${\alpha}$-melanocyte stimulating hormone-stimulated B16F10 melanoma cells without cytotoxicity. These results suggest that MSW cultivation process would be more effective in releasing bioactive compounds with whitening effect from seaweed such as E. cava at an industrial scale.

• Journal of Ecology and Environment
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• v.38 no.1
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• pp.25-38
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• 2015

This study was conducted in an effort to identify the fluctuation of species according to space and time by collecting information on samples of Korean Sphingid moths housed in Korea. The number of Sphingidae moth species housed in Korea was found to be 53. As 48 species and 47 species were found in Gyeongsangnam-do and Gangwon-do, respectively, relatively diverse species were considered to be distributed in these areas. Comparatively, in Jeollabuk-do only 36 species were found, whereas in Chungcheongbuk-do and Jeju Island 39 species were found. The number of individual Sphingid moths surveyed in Korea was 21,414. With regard to the number of individuals per species, Ampelophaga rubiginosa was highest, at 2,483, followed by Theretra japonica (1,716), Callambulyx tatarinovii (1,457), Acosmeryx naga (1,340), Rhagastis mongoliana (1,191), Marumba sperchius (1,083), and Dolbina tancrei (1,072). By region, the largest number of individuals was surveyed in Gyeongsangnam-do (4,595), followed in order by Gangwon-do (3,648 individuals), Gyeonggi-do (3,011), Jeollanam-do (2,454), and Jeju Island (2,382). Over time, the highest numbers-in this case 9,498 individuals in 52 species-were identified after 2000. In the 1990s, there were 6,027 of 49 species identified; in 1980s, 4,332 individuals of 49 species were identified; and, in the 1970s, 937 individuals of 45 species were identified. It was confirmed that more species and individuals were identified as time passed. The appearance of Sphingid moths by month was found to be as relatively diverse, as they appeared from February to November. Overall, southern species, including M. saishiuana, Cephonodes hylas, Acosmeryx castanea, T. nessus, and T. clotho, which mainly inhabit Jeju Island and the southern part of Korea, have increased over time from the past to the present. Species inhabiting the middle or northern parts of the Korean Peninsula or the entire country of Korea, including Sphingulus mus, Ambulyx schauffelbergeri, and Mimas christophi, show decreases over time.

• Journal of Microbiology and Biotechnology
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• v.28 no.3
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• pp.432-438
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• 2018

Microalgae hold promise as a renewable energy source for the production of biofuel, as they can convert light energy into chemical energy through photosynthesis. However, cost-efficient harvest of microalgae remains a major challenge to commercial-scale algal biofuel production. We first investigated the potential of electrolytic water as a flocculant for harvesting Tetraselmis sp. Alkaline electrolyzed water (AEW) is produced at the cathode through water electrolysis. It contains mineral ions such as $Na^+$, $K^+$, $Ca^{2+}$, and $Mg^{2+}$ that can act as flocculants. The flocculation activity with AEW was evaluated via culture density, AEW concentration, medium pH, settling time, and ionic strength analyses. The flocculation efficiency was 88.7% at 20% AEW (pH 8, 10 min) with a biomass concentration of 2 g/l. The initial biomass concentration and medium pH had significant influences on the flocculation activity of AEW. A viability test of flocculated microalgal cells was conducted using Evans blue stain, and the cells appeared intact. Furthermore, the growth rate of Tetraselmis sp. in recycled flocculation medium was similar to the growth rate in fresh F/2 medium. Our results suggested that AEW flocculation could be a very useful and affordable methodology for fresh biomass harvesting with environmentally friendly easy operation in part of the algal biofuel production process.

• New & Renewable Energy
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• v.6 no.2
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• pp.19-26
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• 2010

Experiences in wind farm operation are very limited in Korea, and the foundation for setting standards in power system connection is weak. Therefore, connection and operation standards for wind farms in other countries must be reviewed and power system operation criteria need to be established in order to set up connection standards and optimal operation plans according to the Jeju power system. In this study, reactive power control characteristics of a wind farm were analyzed using a wind farm model of the Jeju power system to propose power system connection operation standards for wind generation within the Jeju power system. Also, change in characteristics of the power system for the application of each reactive power control standard was confirmed, and the results were verified through trial tests arm was analyzed.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.813-816
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• 2009

최근 정보통신 기술을 다양한 분야에 접목하여 융합 서비스를 제공하는 연구 및 개발이 진행되고 있다. 특히 농수산 분야에 RFID 기술을 이용하여 생산 이력 관리하거나 센서 네트워크를 적용하여 생산 환경의 데이터를 수집하고 있다. 본 논문에서는 습도, 온도, 이산화탄소, 조도 센서 등의 양돈 환경을 실시간 감시 응용을 개발하기 위해 지도 기반의 기본 시스템 구조, 데이터베이스 구조, 지도 및 센싱 데이터 도시 알고리즘 등을 제시한다. 이를 통해 각 양돈사에 설치된 센서 데이터를 지도 상에서 직접 현재의 양돈 환경이 상태를 확인하고, 각 시간대별, 센서별로 구분하여 실시간 센싱 데이터를 감시 할수 있다. 이 연구 결과는 돼지들이 성장할 수 있는 최적의 환경을 구축하고, 돼지의 생육에 투입되는 사료 등을 최소화하고 최적의 생육환경을 조성하여 생산성을 높이는 데 도움이 될 것으로 사료된다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.719-724
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• 2015

In this study aiming at the cultured olive flounders in Jeju island of Korea, has performed a total of 216 cases of pathogen tests for the olive flounders which seemingly had the symptom of emaciation in 24 farms on the suspicion of its occurrence from June 2010 to December 2013 and intended to get the basic information about the pathogen. According to the survey results of the emaciation infection status of 24 farms in Jeju over the period of this survey, it was confirmed that 18 (75%) of 24 farms in Jeju are positive in the emaciation infection. Among them, as for the rate of infection per year, it was observed that they are 38% in 2010, 48% in 2011, 50% in 2012 and 60% in 2013, and over the period of this survey the infection rate in accordance with the temperature of water has observed a variety of incidence rates from the summer to the winter season. In addition, according to the results of emaciation infection status for each size, the equivalent showed a detection rate, 54% in 11-20 cm, 43.9% in 21-30 cm and 25.4% in over 31 cm. This result accounts for an important portion among the diseases of farmed olive flounders in Jeju, is considered to be one of the diseases which cause troubles in the farms for olive flounders on land and it is thought that it can be utilized as basic data in order to estimate emaciation which may occur in the similar size of the cultured olive flounders in Jeju island.

• Animal Systematics, Evolution and Diversity
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• v.29 no.2
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• pp.175-178
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• 2013

The Fraser's dolphin, Lagenodelphis hosei has a pantropical distribution. Only several stranding or catch data were available from Japan and Taiwan in the north-west Pacific region. An adult female L. hosei stranded in Jeju-do, Korea. The specimen was identified by external features and skull measurements. It showed the same external appearance ratio and range in the number of teeth with L. hosei former described. The cranial measurements also well corresponded to condylobasal length proportions given in the previous descriptions of the holotype. This is the first record of the species in Korean waters. We report the information on external and osteological characters of the specimen.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.317-319
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• 2012

본 논문은 NFC(근거리무선통신), M2M(사물지능통신) 기술을 활용한 이벤트 응모 단말시스템을 개발하여 관광객들에게 흥미를 유발할 수 있는 이벤트 응모 시스템을 도입, 관광지 이미지 향상으로 인한 관광 수익창출 및 제주관광 서비스를 활성화시켜 제주지역 발전에 크게 기여할 수 있도록 M2M 기반의 이벤트 응모 단말 시스템의 개발 내용을 기술 하였다.