• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.2 s.29
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• pp.169-172
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• 2007

This paper presents circuit models and control algorithms of distributed generation system(DGS) which consists of Z-type converter and PWM inverter. Z-type converter which employs both the L and C passive components and shoot-through zero vectors instead qf the conventional DC/DC converter in order to step up DC-link voltage. Discrete time sliding mode control with the asymptotic observer is used for current control. This system am be used for power conversion of DC renewable energy.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.1
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• pp.167-180
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• 2013

A capstone design is regarded as one of cap courses in undergraduate engineering education because it requires most prerequisites and makes students experience real engineering design processes. There have been case studies to show how this subject should be organized, practiced, and optimized. This study shows one of the case studies by focusing offshore wind power, one of newly recognized renewable energy resources, especially targeting for the design of wind turbine foundation and submarine power cable protectors mainly because of current energy and global warming crisis. To pinpoint engineering design, the students'activities during the project and design procedures are monitored, evaluated, and recommended; hence, core factors are addressed to develop successful aim, theory, practice, and other necessities. These factors include creative problem solving abilities; recognition of engineering curriculum; selection of project theme based on significance, ripple effect, and education purpose; team organization by the full brain model; systematization of project process; realization of engineering design; and synthesis of evaluation. In the end, the aftermath and future works are discussed.

• The Journal of Fisheries Business Administration
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• v.54 no.2
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• pp.59-76
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• 2023

This study is to propose ways to improve the system for rational procedures for offshore wind power generation projects. The results of this study are summarized as follows. In order to quickly distribute and develop offshore wind power projects, the permitting period should be shortened through special laws, the government actively intervenes to support the formation and operation of privat-public councils to ensure residents' acceptance. In this way, it can be competitive in the future energy market. Above all, a special law (proposal) related to offshore wind power currently pending in the National Assembly should be passed as soon as possible. Finally, the government and local governments that manage public waters should provide active administrative support based on system improvement measures in consideration of these permits, and the project's main body should minimize damage to the marine environment and ecosystem. Through these subject-specific roles, offshore wind power generation will be able to reduce carbon emissions and help establish a sustainable energy production system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.50-51
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• 2012

The final purpose of this study is to develop a hybrid ocean power generation system which has innovate and very high efficiency performance, and which can be operated on both emergency and normal conditions. So, A survey on the electricity power consumption of residential areas at island on south coast.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.136-137
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• 2011

The final purpose of this study is to develop a hybrid ocean power generation system which has innovate and very high efficiency performance, and which can be operated on both emergency and normal conditions. So, A survey on the electricity power consumption of residential areas at island on south coast.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.258-261
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• 2009

신재생에너지는 세계적으로 투자급증, 관련기업의 가치상승, 경제성 상승등으로 인해 중요성이 강조되고 있다. 본 연구에서는 미래 먹거리산업 창출에 있어 중요한 신재생에너지 분야 정부지원 연구개발과제(2007~2008)의 투자현황 및 성과를 분석하였다. 연료전지 및 태양광 분야의 투자비중은 신재생에너지 분야 총 투자의 50.7%를 차지하였으며, 지경부는 총 투자의 73.5%를 차지하였다. 수소, 연료전지, 태양광, 해양 분야를 제외한 모든 에너지원에서 지경부의 투자비중이 절대적인 것으로 나타났다. 에너지원별 투자순위가 높은 세부기술을 살펴보면, 수소 분야는 수소제조, 연료전지 분야는 PEMFC, 태양광은 결정질 실리콘, 풍력은 발전시스템으로 나타났다. 연구성과를 살펴보면, 특허건수는 국내 R&D 분야 총 성과의 2.18%에 해당되었으며, 매출액은 0.08% 수준이었다.

• Journal of Ocean Engineering and Technology
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• v.30 no.1
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• pp.57-67
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• 2016

As a new technical approach, an attempt was made to realize a photovoltaic system for an eco-environmental leisure ship by simultaneously actuating nine photovoltaic solar panels in association with the application of a sail-controlling system using wind energy. In this approach, the photovoltaic system consisted of a solar module, an inverter, a battery, and the relevant components, while the sail-controlling device was equipped with sail up/down and mast turning systems. The previously mentioned eco-environmental leisure ship utilizes a photovoltaic hybrid system that uses solar and wind energy as renewable energy sources. Furthermore, this research included a performance evaluation of the manufactured prototype, the acquisition of the purposed quantity values, and development of the purposed items. The significant items, including the sail up/down speed (seconds) and mast turning angle (degrees) were evaluated for a performance test. A wind direction sensitivity of 90% and maximum instant charging power of 900 W were also obtained in the process of the performance evaluation. In addition, the maximum sail time was also evaluated in order to acquire the optimum value. The performance evaluation showed that the prototype with a photovoltaic hybrid system was suitable for sailing an eco-environmental leisure ship using solar and wind energy.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2140-2146
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• 2014

Ocean buoys are operated for safe navigation and collecting ocean data. Recently, to reducing marine buoy's damage by ocean weather's bad condition and collision with vessels has been conducted in several field research. This paper's experiment is buoy condition monitoring about predefined data form by users. As a result using Wireless remote control board applying a radio signal processing algorithms, it can observe buoy's state at an interval of three minutes on the land. Acquired data type is changeable according to ocean weather condition or buoy's purpose of using in advance. Also, this paper conducted an experiment such as data-transmission's stability and wireless communication's availability. As results of the analysis of the transmitted data, the solar, wind and wave power indicates the maximum amount of power, 50 W, 20 W and 40 W respectively. The communication system proven through this research can apply to buoy or other ocean facility.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.2
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• pp.101-108
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• 2016

In designing of the wind power facilities, the highest and lowest astronomical tides (HAT and LAT) are needed in terms of an international design tidal water levels. The AHHW and ALLW, however, have been used as the design tidal levels in Korea. The HAT and LAT in the Wido coastal sea should be estimated to satisfy the standard because the pilot wind power facilities will be located in the adjacent Wido coastal sea. In this study, the HAT and LAT are estimated using the 31-years hourly tidal elevation data of the Wido tidal gauging station and the nodal variation patterns of the major lunar components, such as $M_2$, $O_1$, and $K_1$, are analysed to check the expected long-term lunar cycle, i.e., 18.61-year's nodal variation patterns. The temporal amplitude variations of the $M_2$, $O_1$, and $K_1$ clearly show the 18.61-years periodic patterns in case of the no-nodal correction condition. In addition, the suggested HAT and LAT elevations, estimated as the upper and lower confidence limits of the yearly HAT and LAT elevations, show 40 cm greater than AHHW and 35 cm lower than ALLW, respectively.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.553-560
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• 2020

This paper presents an algorithm for identifying and eliminating errors by seagrasses in coastal bathymetry surveying using drone and HD camera. Survey errors due to seagrasses were identified, segmentated and eliminated using a L∗a∗b color space model. Bathymetry survey using a drone and HD camera has many advantages over conventional survey methods such as ship-board acoustic sounder or manual level survey which are time consuming and expensive. However, errors caused by sea bed reflectance due to seagrasses habitat hamper the development of new surveying tool. Seagrasses are the flowering plants which start to grow in November and flourish to maximum density until April in Korea. We developed a new algorithm for identifying seagrasses habitat locations and eliminating errors due to seagrasses to get the accurate depth survey data. We tested our algorithm at Wolpo beach. Bathymetry survey data which were obtained using a drone with HD camera and calibrated to eliminate errors due to seagrasses, were compared with depth survey data obtained using ship-board multi-beam acoustic sounder. The abnormal bathymetry data which are defined as the excess of 1.5 times of a standard deviation of random errors, are composed of 8.6% of the test site of area of 200 m by 300 m. By applying the developed algorithm, 92% of abnnormal bathymetry data were successfully eliminated and 33% of RMS errors were reduced.