• 한국태양에너지학회 논문집
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• 제32권2호
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• pp.11-18
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• 2012

Diesel fuel is expensive because transportation to remote areas adds extra cost, and it causes air pollution by engine exhaust. Providing a feasible economical and environmental solution to diesel generators is important. A hybrid system of renewable plants and diesel generators can benefit islands or other isolated communities and increase fuel savings. Renewable energy is, however, a natural source that produces a fluctuating power output. In this paper, hybrid power system of the marado lighthouse is proposed to supply stable power in the stand-alone hybrid power system. The proposed hybrid power system consists of the diesel generator, wind turbine, photovoltaic, fuel cell, and battery bank. To decrease the carbon emissions and find the optimization, the cost analysis of hybrid system is simulated using HOMER program and the optimized hybrid power system is designed.

• 건축역사연구
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• 제32권1호
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• pp.35-45
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• 2023

Bongsu(Beacon Fire Station) is a facility that sends signals with fire and smoke and has been used in Korea since the Three Kingdoms period. This facility was installed to know the north and south crises. This trend continues until the Joseon Dynasty, and it has been somewhat completed in the 17th century. In previous studies, beacon fire was identified mainly from the border area to Hanyang. Based on this, it was classified into Gyeongbongsu, Yeonbyeonbongsu, and Naejibongsu. However, it is difficult to define the characteristics of beacon fire in coastal areas only with this classification. In the case of beacon fire in island areas, there was a tendency to value communication connection within the region rather than connection with the capital. As a case analysis for this, an academic review was conducted with the cases of Ganghwa Island and Jeju Island. As a result, it was confirmed that the role and character of the beacon vary depending on the defense system and the physical distance from the land, even if it has the topographical commonality of the same island.

• 한국패류학회지
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• 제17권1호
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• pp.63-70
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• 2001

1999년 9월부터 2000년 8월까지 제주도 안덕면 화순리 화순화력발전소 인접 5개 지점 조간대의 대형저서무척추동물의 분포와 군집구조에 관한 연구결과는 다음과 같다. 화순화력발전소 인접 조간대에 분포하는 대형무척추동물은총 6 문, 13 강, 24 목, 49 과, 97 종이 출현하였다. 조간대 상부구역의 제 1 우점종은 좁쌀무늬총알고둥, 제 2우점종은 군부 (Liolophura japonica), 테두리고등 (Patelloida saccharina), 배무래기 (Notoarmea schrenckii) 이였다. 중부구역의 제 1 우점종은 울타리고등 (Monodonta labio), 작은조무래기따개비 (Chthamalus challengeri), 고랑딱개비 (Siphonalia japonica), 군부 (L. japonica), 울타리고등 (M. labio)이였으며, 제 2 우점종은 배무래기 (N.schrenckii), 울타리고등 (M. labio), 진주담치 (Mytilus edulis), 거북손 (Mitella mitella), 군부 (L. japonica) 이였다. 하부구역의 제 1 우절종은 꽃고랑딱개비 (Siphonalia sirius), 작은조무래기따개비 (C. challengeri), 해변말미잘(Actinia mesembryanthemum), 테두리고등 (P. saccharina), 울타리고등 (M. labio) 이였으며, 제 2 우점종은 배무래기 (N. schrenckii), 군부 (L. japonica), 석회관갯지렁이(Serpula vermicularis), 울타리고등 (M. labio)이였다. 조간대 종다양도지수나 균등도, 풍부도는 하부구역이 상부구역이나 중부구역에 비하여 컸다.

• 한국안광학회지
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• 제11권3호
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• pp.231-240
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• 2006

본 연구는 제주도 소재 남녀 중학생 492명을 대상으로 안경/콘택트렌즈 착용률, 시력검사 장소 및 시기, 안경/콘택트렌즈 교체 시기 비용 이유, 안경착용과 거주지역간의 상관성 등에 관하여 설문조사를 실시하여 다음과 같은 결과를 얻었다. 1. 조사 대상자의 45.33%가 시력교정을 위한 안경 또는 콘택트렌즈를 착용하는 것으로 조사되었다. 이 중에서 안경만 착용하는 학생이 93.27%, 안경과 콘택트렌즈 병용이 5.83%, 콘택트렌즈만 착용이 0.90%로 조사되었다. 2. 안경교체 시기는 6개월 미만이 20.18%, 6개월에서 1년 미만이 52.02%, 1년에서 2년 미만이 20.18%, 2년 이상이 7.62%로 조사되었다. 3. 안경구입시 사용하는 비용은 3만원 미만이 13.45%, 3만원 이상 5만원 미만이 43.50%, 5만원 이상 7만원 미만이 23.77%, 7만원 이상 10만원 미만이 15.25%, 10만원 이상이 4.03%로 조사되었다. 4. 안경교체 이유는 시력변화로 인해서가 55.16%, 안경 또는 렌즈의 파손으로 27.35%, 안경이나 렌즈를 바꾸고 싶어서 14.80%, 기타 2.69%로 조사되었다. 5. 안경구입시 안경테/안경렌즈의 상대적인 중요도에 관해서는 안경테가 더 중요하다는 학생이 16.59%, 안경렌즈가 더 중요하다는 학생이 24.67%, 안경테와 안경렌즈 모두 중요하다는 학생이 58.74%였다. 6. 처음으로 시력검사를 한 시기는 초등학교 1학년이 32.29%, 초등학교 3학년이 12.56%, 초등학교 4학년이 11.66%, 초등학교 6학년이 11.66%로 조사되었다. 7. 현재 사용 중인 안경 또는 콘택트렌즈를 착용하기 위해서 시력검사를 받은 장소는 안경원이 57.85%, 안과나 병원이 42.15%로 조사되었다. 8. 처음으로 시력교정을 위해 안경 또는 콘택트렌즈 착용한 시기는 초등학교 6학년 때라고 응답한 학생이 21.97%로 가장 많았다. 9. 나안 양안사력이 좋지 않음(0.8 미만)에도 불구하고, 안경 또는 콘택트렌즈를 사용하지 않는 이유로는 각각 일상생활을 하는데 불편함을 느끼지 못해서가 62.5%, 주변에서 안경을 사용하면 눈이 더 나빠진다고 해서가 15.63%, 경제적인 이유로 6.24%, 외관상 좋아 보이지 않아서가 15.63%로 조사되었다.

• 한국수산과학회지
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• 제40권6호
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• pp.394-410
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• 2007

Anchovy spawn from the end of May to mid-October, when the water temperature is $14.8-27.2\;^{\circ}C$ and the salinity is 26.0-33.6 psu. The main spawning season is between July to August, when the water temperature is $21.7-27.2\;^{\circ}C$ and the salinity is between 26.0-32.2 psu. The main spawning grounds of anchovy are coastal areas shallower than 50 m around the islands located in the Jeju Strait. Anchovy larvae are distributed near the fronts between Chuja-do, Jangsu-do, Yeoseo-do, and the open sea rather than in the spawning grounds. Anchovy eggs and larvae density increased in accordance with the high level of $Chlorophyll-{\alpha}$ during the summer season (July-August). In terms of the suspended sediment (SS) levels along the northern coast of the Jeju Strait, high densities of anchovy eggs (12.0-18.0 mg/L) were observed, mainly in the area affected by the coastal waters of the southern sea with high SS levels, while larvae (10.0-19.0 mg/L) tended to be distributed over a wide area with high SS levels, including the open sea. In terms of the dissolved oxygen (DO) content, eggs (5.4-6.8 mg/L) were observed in coastal areas with a high DO content, while larvae (4.2-6.4 mg/L) were distributed widely in areas with a relatively low DO content, from the southern coast to the open sea.

• 한국지형학회지
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• 제18권4호
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• pp.79-96
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• 2011

화산지형은 분화에 따른 건설적인 작용으로 만들어지는 화산체와 파괴적인 작용에 의한 화구지형으로 구분할 수 있다. 한반도에는 두 유형의 화산지형이 모두 출현하고 있으나 현재 화산지형으로 인식되고 있는 사례는 제4기의 분화활동과 관련된 백두산, 제주도, 울릉도 그리고 중부지방의 추가령 일대에 국지적으로 분포하고 있다. 그 결과 우리나라에서 화산지형은 특수한 지형으로 분류되고 있다. 해방 이후 국내 연구자에 의한 화산지형 연구는 제주도는 1970년대, 울릉도와 추가령은 1980년대 그리고 백두산은 1990년대부터 본격적으로 시작되었다. 또한 제주도의 오름과 용암동굴에 관한 연구도 1980년대부터 시작되었다. 그러나 지형학의 다른 분야에 비하여 연구자와 연구성과는 매우 적은 편으로, 한반도 화산지형이 갖고 있는 가치를 고려할 때 앞으로 지형학자들의 적극적인 연구활동이 기대되는 분야이다.

• Structural Engineering and Mechanics
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• 제88권4호
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• pp.323-334
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• 2023

The submerged floating tunnel (SFT) infrastructure has been regarded as an emerging technology that efficiently and safely connects land and islands. The SFT route problem is an essential part of the SFT planning and design phase, with significant impacts on the surrounding environment. This study aims to develop an optimization model considering transportation and structure factors. The SFT routing problem was optimized based on two objective functions, i.e., minimizing total travel time and cumulative strains, using NSGA-II. The proposed model was applied to the section from Mokpo to Jeju Island using road network and wave observation data. As a result of the proposed model, a Pareto optimum curve was obtained, showing a negative correlation between the total travel time and cumulative strain. Based on the inflection points on the Pareto optimum curve, four optimal SFT routes were selected and compared to identify the pros and cons. The travel time savings of the four selected alternatives were estimated to range from 9.9% to 10.5% compared to the non-implemented scenario. In terms of demand, there was a substantial shift in the number of travel and freight trips from airways to railways and roadways. Cumulative strain, calculated based on SFT distance, support structure, and wave energy, was found to be low when the route passed through small islands. The proposed model helps decision-making in the planning and design phases of SFT projects, ultimately contributing to the progress of a safe, efficient, and sustainable SFT infrastructure.

• 한국항공운항학회지
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• 제32권2호
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• pp.142-150
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• 2024

Improving transportation accessibility on islands is closely related to regional development. Currently, the government is constructing Ulleung Airport as part of the 6th Airport Mid- to Long-term Development Plan. Similar to the case of Jeju Airport in 2016, severe congestion occurs at passenger terminals upon flight resumption after cancellations at airports on islands. Therefore, considering the cancellation rate at island airports is important. This study investigates the conditions leading to increased cancellation rates at Ulleung Airport, with the research results predicting frequent cancellations during the winter season. The research methodology involved examining airport construction plans, aircraft performance, airport de-icing capabilities, and also included consideration of weather conditions. Ulleung Island is a representative snowfall area, and sufficient snow removal capacity must be secured. However, the current plan's snow removal capacity is insufficient, leading to anticipated high cancellation rates. Therefore, measures to mitigate passenger inconvenience caused by increased cancellations and methods to reduce the cancellation rate are explored. With Ulleung Airport scheduled to open in 2027, there is ample time to implement supplementary measures to reduce the cancellation rate and minimize passenger inconvenience.

• Ocean and Polar Research
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• 제43권4호
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• pp.205-217
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• 2021

A shallow channel between Jeju and Udo Islands, which is located in the northeastern Jeju Island, is influenced by storm- or typhoon-induced currents and surface waves as well as strong tidal currents. This study examines the typhoon-induced current and wave patterns in the channel, using Acoustic Doppler Current Meter (ADCP) measurements and an ocean-wave coupled modeling experiment. Three typhoons were chosen - Chaba (2016), Soulik (2018), and Lingling (2019) - to investigate the responses of currents and waves in their pathways. During the pre-typhoon periods, dominant northward flow and wave propagation were observed in the channel due to the southeasterly winds before the three typhoons. After the passage of Chaba, which passed over the eastern side of Jeju Island, the northward flow and wave propagation were totally reversed to the opposite direction, which was attributed to the strong northerly winds on the left side of the typhoon. In contrast, in the cases of Soulik and Lingling, which passed over the western side of Jeju Island, strong southerly winds on the right side of the typhoons continuously intensified the northward current and wave propagation in the channel. The model-simulated current and wave fields reasonably coincided with observational data, showing southward/northward flow and wave propagation in response to the right/left side of the typhoon pathways. Typhoon-induced downwind flows, and surface waves could enhance up to 2m/s and 3m due to the strong winds that lasted for more than 12 hours. This suggests that the flow and wave patterns in the Udo channel are highly sensitive to the pathway of typhoons and accompanying winds; thus, this may be a crucial factor with regard to the movement of seabed sediments and subsequent coastal erosion.

• 수산해양기술연구
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• 제53권2호
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• pp.187-195
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• 2017

We have studied the efficient operation of the radar and the appropriateness of the installation location, when constructing the VTS system. As the Civil-Military Complex Harbour (Kangjeong Port) is completed in 2016, we set the control area within 10 nautical miles centering on Kangjeong Port, and found out and removed the operational radar blind area of VTS system to provide safe navigation information for vessels that navigating this area. Assuming that two international cruise ships entering at the same time, we performed the radar simulation and compared the images by considering the three sites of Kangjeong Port, Miaksan and Seoguipo Port. Simulation results for a single radar installed at Kangjung Port indicate that the blind area was largely affected by two large cruise ships and the surrounding islands. The blind area due to Kogunsan was considerably large when installed in Miaksan, but the blind area due to the influences of Beomseom, Moonseom and Seopseom was negligibly large. It seems that additional radar installation is necessary as a complementary solution to solve this blind area. When two radars were installed at Miaksan and Kangjeong Port, the residual blind area due to the Seopseom was $0.25km^2$ at 0.1~0.33 nautical miles in the southeast direction from Seopseom. In addition, the remaining blind area with two cruise ships mutually influenced was $0.18km^2$, which did not occur with a single cruise ship.