• Title/Summary/Keyword: Jeju Region

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Effect of Seeding Date on Forage Yield and Chemical Composition of Echinochloa crusgalli var. Frumentacea(Roxb) Wight in Jeju Region (제주지역에서 파종기에 따른 청예피의 사료수량 및 조성분 변화)

  • 조남기;강영길;송창길;고영순;조영일
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.21 no.4
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    • pp.217-224
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    • 2001
  • In order to identify the growth characterization, the yield and chemical composition of Jeju barnyard grass (Echinochloa crusgalli var. fiurnentacea(Roxb) Wight) based on seeding date in Jeju region, seeding carried out the 10-day intervals from March 27 to September 30 in 2000, respectively. Plant height was 143.2 cm, showing the highest on seeding date, April 6 among that of any other seeding date. On the other hand, those of early and late seeding gradually decrease. Plant height was 119.2 an in May 16 seeding. The results of stem diameter, number of withering leaves, number of leaves and fresh weight per plant were similar to those of the plant heights. The yield of fresh, dry matter forage, crude protein and TDN found the highest on April 6 seeding, 63.5 MT/ha, 13.9 MTha, 1.1 MT/ha, and 7.6 MT/ha, respectively. In early and late seeding, the yield was gradually decreased. In seeding May 16, the yield found .38.2 MTIha in fresh forage, 6.2 MTha in dry matter forage, 0.7 MT/ha in crude protein and 3.7 MTha in TDN, respectively. According to delaying the seeding date, March 27 to May 16, the contents of crude protein (from 7.9 to 10.8%), ether extract (from 4.6 to 6.0%), nitrogen free extract (from 45.1 to 46.5%), and TDN (from 54.2 to 60.8%) were gradually increased, respectively. On the other hand, those of crude fiber (from 28.9 to 25.6%) and crud ash (from 13.5 to 11.2%) were decreased. These results showed that April 6 was the optimum seeding date with the sole object of feed production of Jeju barnyard grass under the environmental condition like as atmospheric phenomena and soil in Jeju region. (Key words : Jeju barnyard grass, Seeding date, Forage yield, Chemical composition)

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Study on the Power Performance on WindPRO Prediction in the Southeast Region of Jeju Island (제주 남동부 지역을 대상으로 한 WindPRO의 발전량 예측에 관한 연구)

  • Hyun, Seunggun;Kim, Keonhoon;Huh, Jongchul
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.184.1-184.1
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    • 2010
  • In order to research the way to evaluate wind resource without actual Met Mast data, this paper has been carried out on the southeastern region of Jeju island, Korea. Although wind turbine has been an economical alternative energy resource, misjudging the prediction of lifetime or payback period occurs because of the inaccurate assessment of wind resource and the location of wind turbine. Using WindPRO(Ver. 2.7), a software for wind farm design developed by EMD from Denmark, wind resources for the southeastern region of Jeju island was analyzed, and the performance of WindPRO prediction was evaluated in detail. Met Mast data in Su-san 5.5Km far from Samdal wind farm, AWS in Sung-san 4.5km far from Samdal wind farm, and Korea Wind Map data had been collected for this work.

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Analysis of Water Level Fluctuations according to Groundwater Development and Pumping Duration (지하수 개발 및 양수기간에 따른 수위 변동특성 분석)

  • Kim, Min-Chul;Yang, Sung-Kee;Lee, Jun-ho
    • Journal of Environmental Science International
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    • v.25 no.1
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    • pp.135-146
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    • 2016
  • This study analyzed fluctuations of ground water level of ground water wells developed in Seongsan watershed of Jeju Island until 2013 using MODFLOW, a numerical analysis model. Ground water level shows greater fluctuations from increase of pump capacity compared to the number of ground water wells. The development of ground water at the top of watershed was found to have direct influence on ground water level. Ground water wells developed until 2013 were used to continue pumping for 50 days, and ground water level of coastal region was reduced below 50% compared to the standard water level. In addition, the range of fluctuation of water level was large in the east coast region, which represents the direction of flow of ground water.

Characteristics of Water Temperature Inversion Observed in a Region West of Jeju Island in April 2015 (2015년 4월에 제주 서부해역에서 발생한 수온역전층 특성)

  • Kim, Seong Hyeon
    • Ocean and Polar Research
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    • v.42 no.2
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    • pp.97-113
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    • 2020
  • In-situ observations were carried out in April 2015 to investigate the occurrence of water temperature inversion in a region west of Jeju Island. Analysis of in-situ in the western part of Jeju island showed that cold water moved to the southeast from the surface to the middle layer and warm water moved from the middle to the lower layer of the northwest direction. The water temperature inversion occurred at 84 stations (63.1%) out of 133 stations. At the boundary of the water temperature inversion layer, it was formed in the middle layer and disappeared. In the strongly appearing, it started from the middle layer to the lower layer. The shape of the water temperature inversion layer was different. As a result of horizontal water temperature slope analysis of the water temperature inversion zone, maximum 0.23℃/km was obtained and the mean was 0.06℃/km. The role of water temperature inversion as an indicator to determine the formation of water front. As a result of the water mass analysis, Jeju Warm Current Water and Tsushima Warm Current Water of high temperature and high salt intruded from the middle to the bottom. In the middle layer occurred as the Yellow Sea Cold Water of low water temperature and low salinity expanded.

A Study of Characteristics of Business Cycle in the Jeju Region (제주지역 경기변동의 특성 연구)

  • Kang, Min-Seo;Kang, Gi-Choon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.1
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    • pp.420-426
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    • 2018
  • The purpose of this paper is to examine the business cycle in the Jeju region and what differences exist in relation to the nation as a whole, to calculate the relative importance between the random walk stochastic trend and cyclical factor, and to find out its causes and implications. Results of empirical analysis found that the characteristics of the business cycle in the Jeju region were as follows: First, the Jeju region, which is likely to have a growth component of the economy such as technological development and the accumulation of capital, was projected to have a possibility of high growth due to a greater proportion of the stochastic trend factor(46.8%) than the entire country(27.8%). Secondly, employment fluctuation in Jeju, which varies from 0.007 to 0.058 depending on the model, was lowest compared to the fluctuation of other indicators. The employment market in Jeju remained firm, showing that it is not smooth enough to create new jobs despite the production growth in industry. Third, the tourism industry was acting as a stabilizing factor, whereas the mining and manufacturing production was the opposite of tourism industry. This implies that the mining and manufacturing production was based on a weak foundation.

Physical and Mechanical Characteristics of Basalts in Northwestern and Southeastern Jeju Island (제주도 북서부 및 남동부 현무암의 물리적 & 역학적 특성)

  • Yang, Soon-Bo
    • Journal of the Korean Geotechnical Society
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    • v.31 no.7
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    • pp.41-52
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    • 2015
  • Volcanic rocks in Jeju Island have vesicular structure caused by various environmental factors, and indicate the differences in geological and mechanical characteristics from region to region. In addition, the bedrock of Jeju Island shows stratified structure, that is, soft layers composed of pyroclastic rocks or cavities are irregularly developed between the basalt layers by several times of volcanic activity. In this study, various physical tests and unconfined compressive strength test were conducted for intact rocks sampled in northwestern onshore and offshore of Jeju Island. The results obtained in the tests were compared with the physical and mechanical characteristics of intact rocks sampled in southeastern offshore of Jeju Island. As a results, it was confirmed that the physical and mechanical characteristics of basalts sampled in northwestern Jeju Island were similar to those of basalts sampled in southeastern offshore of Jeju Island. In addition, it was possible to estimate approximate design parameters from the correlation of mechanical properties with physical properties of basalts in Jeju Island.

Comparative Study on Physical and Mechanical Characteristics of Volcanic Rocks in Jeju Island (제주도 화산암의 물리・역학적 특성에 대한 비교연구)

  • Yang, Soon-Bo
    • Journal of the Korean Geotechnical Society
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    • v.30 no.11
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    • pp.39-49
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    • 2014
  • Volcanic rocks in Jeju island show vesicular structure caused by various environmental factors, and indicate the differences in geological and mechanical characteristics from region to region. Previous studies on the volcanic rocks in Jeju island have been actively conducted on geological and chemical properties in terms of geophysics and geology and on physical and mechanical properties in terms of engineering. But comprehensive comparative analysis on physical and mechanical properties of volcanic rocks in Jeju island is not conducted. In this study, the physical and mechanical properties of volcanic rocks in Jeju island were compared and analyzed comprehensively through the existing research papers and reports about volcanic rocks in Jeju island. As a result, it was found that the relationship between absorption (porosity) and apparent specific gravity is commonly linear and could be represented as two different linear approximations. In addition, it was found that the relationship between P-wave velocity and S-wave velocity and the relationship between absorption (porosity) and uniaxial compressive strength could be classified more clearly, considering two different linear relationships in absorption (porosity) and apparent specific gravity.

Observational Study of Surface Ozone in Jeju Island

  • Hu Chul-Goo;Lee Ki-Ho
    • Journal of Environmental Science International
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    • v.14 no.12
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    • pp.1103-1112
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    • 2005
  • Ozone measurements made from 4 sites in Jeju Island have been analyzed, including those from two urban and two rural locales. The data were analyzed in terms of the seasonal and diurnal trends. It should be clear that the surface ozone levels in Jeju area would be relatively sensitive to the external ozone supply originated from the region of Northeast Asia. It seems to be that due to the reactions of ozone with $NO_{x}$ and CO, the average ozone level in Jeju City appears lower than that in Seogwipo City although Jeju City is the largest city in Jeju Island.

Estimation of Probable Precipitation considering Altitude in the Jeju Islands (제주도의 고도를 고려한 확률강우량 산정)

  • Ko, Jae-Wook;Yang, Sung-Kee;Jung, Woo-Yul;Yang, Se-Chang
    • Journal of Environmental Science International
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    • v.23 no.4
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    • pp.595-603
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    • 2014
  • Jeju Island, a volcanic island, is the region that shows the biggest rainfall and has a big elevation-specific deviation of precipitation, but Jeju Island River Maintenance Plan doesn't reflect the characteristics of Jeju Island as it only calculates probable precipitation from four weather stations with elevation less than 100m. Therefore, this study uses AWS observational data in four Jeju Island weather stations and other regions to calculate location-specific probable precipitation, review the elevation-probable precipitation correlation in southern and northern regions, and create a probable precipitation map for all regions of Jeju Island, in order to produce better outcomes. This study is expected to be the most basic data to establish a safe Jeju island from flood disaster in preparation for the future climate changes and widely used for Jejudo Basin Dimension Planning, River Maintenance Plan, Pre-Disaster Impact Review, etc.

Improvement of Infiltration Performance Measurement in BTL (Build-Transfer-Lease) Sewer Rehabilitation Projects - Focusing on Jeju Special Self-Governing Province - (하수관거정비 임대형민자사업에 있어 침입수 성과지표의 개선에 관한 연구 - 제주특별자치도를 중심으로 -)

  • Ko, Young-Nam;Lee, Dong Wook
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.36 no.6
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    • pp.1133-1143
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    • 2016
  • The purpose of this study is to improve project performance analysis indicators for BTL sewer rehabilitation projects. Among the assessment indicators for BTL sewer rehabilitation projects, an infiltration assessment indicator is given a high score of 17.5 points as a single assessment item. This infiltration assessment indicator is assessed focusing on the amount of infiltration, and presently calculated according to 'Nighttime Domestic Flow Evaluation' method. However, this assessment indicator's failure to reflect the geological features of Jeju region is emerging as a problem in the operational stage. Thus, this study intended to compare and analyze the calculation result depending on the assessment indicators and the actual amount of infiltration, centering on Jeju region. To this end, this study analyzed the amount of infiltration in five areas of Jeju Province calculated according to 'Nighttime Domestic Flow Evaluation' method. Also, a complete enumeration survey was carried out about the conditions for actual infiltration occurrence. According to the results of this survey, ground water level is distributed lower than the level of sewer pipes. The results of a sewer pipe function test show there was no infiltration occurrence caused by sewer pipe defect. So, it is concluded that 'Nighttime Domestic Flow Evaluation' method, which is utilized for the current assessment indicator, is not appropriate to apply to Jeju region, and it is thought that there is a need to establish infiltration criteria specialized for Jeju region.