• Korean Journal of Materials Research
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• v.6 no.9
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• pp.972-978
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• 1996

본 논문에서는 1673K에서 소결한 PSZ/Ni 복합재에 대한 종 탄성계수, 파괴강도, 파괴에너지 등의 기계적 특성을 평가하기 위해, 개량형 소형펀치시험을 행한 결과에 대해 논의한다. 또한 파면관찰과 AE법을 통해 이들 재료의 고온환경에서의 미시파괴과정도 조사하였다. 시험온도는 293K, 1073K, 1273K, 1473K의 4종류로 하였으며, PSZ/Ni 복합재료의 체적 조성비도 80/20, 60/40, 40/60, 20/80의 4종류이다. 이들 실험결과로부터, 1073K이상의 고온에서 Ni 함량이 60%인 PSZ/Ni 복합재가 파괴강도 및 파괴에너지가 가장 우수한 것을 알았다. 파면관찰에 의하면 이 재료의 조성비에서 파고거동이 취성으로부터 연성으로 천이하는 것을 확인할 수 있었다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.3
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• pp.53-64
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• 2001

Bathing beach may be one of the ocean resorts in popular, which peoples can easily access in summer. Three beaches in Jeiu island are surveyed about natural environmental conditions using coastal engineering technique and questionnaire are carried out. Also the satisfaction index on the sand size, wave height, water temperature, transparency and bottom slope is gained very well. The results obtained from this study can be utilized making a new artificial bathing beach in the future.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.38.1-38.1
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• 2011

This study investigates the effects of Pierson-Moskowitz, Jonswap spectrum that are typical irregular wave spectrums for wind turbine system with jacket support structure. Also various offshore environmental parameters based on korean local condition were used in our study. The loads acting on the system was considered by referring to the Design Load Case from IEC guide line. And improved von Karman model was used as a turbulence model. As a result, various significant wave height and peak spectral period cause noticeable difference of extreme and fatigue loads prediction.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.353-354
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• 2018

스웰 등 장주기파랑은 높은 에너지를 갖고 있어서 바람이 없어도 에너지가 사라지지 않고 전파되어 항만에 이르게 되고, 차폐된 항내수역에서 파고가 증폭되어 대형선박의 접이안과 하역작업을 중단시키는 경제적 손실을 야기한다. 본 실험은 대규모 개발에 따른 장주기 파랑에 의한 반응특성과 부진동의 영향을 검토하였다. 특히, 항만확장외에 외역에 추가적 개발을 위한 매립을 고려하여 항만정온도와 장주기 반응 특성을 파악하여 가능한 대책방향을 검토하고자 하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.1
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• pp.10-15
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• 2012

Wave characteristics in the presence of energy damping are investigated using the linear shallow water equations. To get the phase and energy velocities, geometric optics approach is used and then these values are validated through numerical experiments. Energy damping affects wave height, phase and energy velocities which result in wave transformation. When the complex wavenumber is used by the Eulerian approach, it is found that the phase velocity decreases as the damping increases while the energy velocity increases showing higher values than the phase velocity. When the complex angular frequency is used by the Lagrangian approach, the energy-damping wave group is found to propagate in the energy velocity. The energy velocity is found to affect shoaling and refraction coefficient which is verified through numerical experiments for waves on a plane slope.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.4
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• pp.139-147
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• 2021

In this study, waves were defined using the water surface elevation data observed from the HeMOSU-1 and 2 marine meteorological observation towers installed on the west coast of Korea, and correlation analysis was performed between wave parameters. The wave height and wave period were determined using the wave-train analysis method and the wave spectrum analysis method, and the relationship between the wave parameters was calculated and compared with the previous study. In the relation between representative wave heights, most of the correlation coefficients between waves showed a difference of less than 0.1% in error rate compared to the previous study, and the maximum wave height showed a difference of up to 29%. In addition, as a result of the correlation analysis between the wave periods, the peak period was estimated to be abnormally large at rates of 2.5% and 1.3% in HeMOSU-1&2, respectively, due to the effect of the bimodal spectrum that occurs when the spectral energy density is small.

• JOURNAL OF ELECTRICAL WORLD
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• s.351
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• pp.89-94
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• 2006

에너지 해외의존도 97%, 무역의존도 70%인대한민국. 우리는하루220만배럴, 연간8억배럴이상을소비한다. 부존자원이 극도로 빈약한 우리나라가 나아가야 할 길은자명하다. 에너지 자원을 거의수입해 의존하다보니 이를고부가화 해 내수에 돌리면서 최우선으로 수출을 통해 온나라가 먹고 살고 있다해도 과언이아니다. 해외 에너지자원을 안정적으로 확보하는 것이 바로 국가경쟁력의 근원이 되는것은 어제오늘의 일이 아니다. 고유가 파고를 헤쳐나가야 한다는 절박한현실에서안정적인 에너지자원확보를 위한 정부의 해외자원분야 정책 및 민관전략이 올들어 의욕적으로 전개되고 있다. 우선정부는 자원개발 업무를 강화하기 위해 현재1과1팀의 자원개발조직을 보강하 고유전개발팀을 신설하는 등 모두3개팀으로 늘린다. 나아가 해외 자원확보에주력 산업 동반진출도 착착진행하고 있다. 국내 자원 개발 기업과 에너지관련기업, 해외진출기관등 14곳으로 구성된 ‘에너지산업해외진출협의회’도 최근 출범시켰다. 유전을탐사하거나 개발하는데 개인들도간접투자할수있는 ‘유전개발펀드’도 7월에 첫 선을 보인다. 약2000억원규모의이 시범펀드 도입 등을 통해 자원개발을 가속화,2013년까지원유-가스자주개발률을18%(원유15%, 가스30%)까지 끌어 올릴 계획이며 여기에16조원 신규투자가 소요 될 것으로보고있다. 이같은 일련의 공격적인 움직임은 단순히 돈을 주고 자원을 사오는 기존방식을 앞으로는과감히탈피,자원부국이 원하는 산업인프라등을 수주해제 공한뒤 그 대가로자원을 확보하는 총체적 자원확보전략에 무게를두겠다는 의지를 담고 있어 고무적이다. 여기에 다원유 등 수입원자재 가격이 급등세를 보이고있는 가운데 우리나라의 해외 자원개발사업이 활기를 띠고있다.석유공사는 민간기업들과 함께 지난해에만 예멘2곳 등 전세계 5개국9곳의 석유 및 천연가스 광구계약을체결, 올들어 최근참여사들과 함께 주주간계약 서명식을 갖고본격적인 사업을 추진 중이다. 광업진흥공사역시 SK네트웍스와제휴, 최근 전체 매장량이650만t으로 추정되는 중국 후난성의 아연광 탐사권을 획득, 합작 사설립계약을 체결한 것으로 알려지고 있다. 민간기업들도 해외자원분야진출이 활발하다. 기업들의 해외 자원개발을 위한 투자규모도 늘어 올해38개 해외 자원개발기업이 32개국 211개 사업에 모두31억달러를 투자할 계획인것으로 나타났다. 이에본지는 올해 들어서도 고유가의 지속으로 속증하고 있는에너지수입동향과 해외 자원 개발의 현실과 문제점, 개선방향, 나아가 최근 안전적인 자원확보를 위한 동향을 진단해본다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.3 no.1
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• pp.14-20
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• 1991

Accurate estimation of irregular wave transformation when the waves propagate from deep water to shallow water region is very important for the design of coastal structures and establishing beach erosion control. In this study. the transformation of directional spectrum is tested numerically using a conservation equation for energy flux and. based upon the joint distribution of wave height. period and wave direction. shoaling effects are predicted in the shallow water region. The applicability of the proposed procedure is verified through comparison with field observation data.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.2
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• pp.49-59
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• 2000

Wave distribution in Jangjeon Harbour is numerically simulated for an optimum design of the harbour facilities. A deep-water design wave is estimated based on stochastic extreme wave analysis of wind data in the vicinity of the harbour, and it is applied to the boundary condition at open sea. Boussinesq wave theory that includes effects of frequency dispersion and nonlinearity is employed for the wave simulation. The porosity and sponge layer are adapted at beach to depict partial reflection and complete absorption of waves, respectively. The design wave for breakwater is computed in global domain with coarse grids and the wave distribution inside of wharf is simulated in local domain with fine grids.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.3
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• pp.147-153
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• 2013

There exist various types of the WEC (Wave Energy Converter), and among them, the point absorber is the most popularly investigated type. However, it is difficult to find examples of systematically measured data analysis for the design of the point absorber type of power buoy in the world. The study investigates the wave load acting on the point absorber type resonance power buoy wave energy extraction system proposed by Kweon et al. (2010). This study analyzes the time series spectra with respect to the three-year wave data (2002.05.01~2005.03.29) measured using the pressure type wave gage at the seaside of north breakwater of Hupo harbor located in the east coast of the Korean peninsula. From the analysis results, it could be deduced that monthly wave period and wave height variations were apparent and that monthly wave powers were unevenly distributed annually. The average wave steepness of the usual wave was 0.01, lower than that of the wind wave range of 0.02-0.04. The mode of the average wave period has the value of 5.31 sec, while mode of the wave height of the applicable period has the value of 0.29 m. The occurrence probability of the peak period is a bi-modal type, with a mode value between 4.47 sec and 6.78 sec. The design wave period can be selected from the above four values of 0.01, 5.31, 4.47, 6.78. About 95% of measured wave heights are below 1 m. Through this study, it was found that a resonance power buoy system is necessary in coastal areas with low wave energy and that the optimal design for overcoming the uneven monthly distribution of wave power is a major task in the development of a WEF (Wave Energy Farm). Finding it impossible to express the average spectrum of the usual wave in terms of the standard spectrum equation, this study proposes a new spectrum equation with three parameters, with which basic data for the prediction of the power production using wave power buoy and the fatigue analysis of the system can be given.