• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.2
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• pp.81-95
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• 2014

In the present study, the statistical analysis on the storm waves in the East Sea have been carried out, and the several storm waves were reproduced by the modified WAM as a first step for the accurate and prompt forecasting and warning against the swell waves in East Sea. According to the present study, the occurrences of the storm waves from the North were the most probable, while the waves from the Northeast were most frequently observed. It was found that the significant wave heights of storm waves from the North and Northern northeast were larger than those of storm waves from the Northeast. But due to long fetch distance, the significant wave periods of storm waves from the Northesast were longer than those of North and Northern northeast. In addition to the wave analysis, the numerical experiments for the storm waves in East Sea were carried out using the modified WAM, and three periods of storm waves in 2013 were calculated. The numerical results were well agreed with wave measurements. However the numerical simulation results in shallow water region showed lower accuracies compared to deep water, which might be due to lower resolution of wind field and bottom topography caused by large grid size, 5 minute, adopted in the present study. Overall computational efficiency of the modified WAM found to be excellent compared to original WAM. It is because the modified WAM adopted the implicit scheme, thereby the present model performed 10 time faster than original WAM in computation time.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.6
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• pp.286-297
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• 2018

In the present study, wave measurements at KOGA-W01 were analyzed and then the numerical wind waves simulations have been conducted to investigate the characteristics of wind waves in the Yellow sea. According to the present analysis, even though the location of the wave stations are close to the coastal region, the deep water waves are prevailed due to the short fetch length. Chun and Ahn's (2017a, b) numerical model has been extended to the Yellow Sea in this study. The effects of tide and tidal currents should be included in the model to accommodate the distinctive effect of large tidal range and tidal current in the Yellow Sea. The wave hindcasting results were compared with the wave measurements collected KOGA-W01 and Kyeockpo. The comparison shows the reasonable agreements between wave hindcastings and measured data, however the model significantly underestimate the wave period of swell waves from the south due to the narrow computational domain. Despite the poorly prediction in the significant wave period of swell waves which usually have small wave heights, the estimation of the extreme wave height and corresponding wave period shows good agreement with the measurement data.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1995.10a
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• pp.57-60
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• 1995

연안에서 파랑은 심해에서는 해수면 근방에서 운동량이 크며 따라서 구조물에 작용하는 힘도 해수면 근방에서 크다. 반면 천해역에서는 해저면에서의 운동량도 상당하며, 이러한 해저면에서의 파랑에 관련된 수입자의 운동은 해저 퇴적물의 이동에 직접 영향을 미친다. 해저면에서의 비활 조건(no-slip condition)에 의하여 파랑 경계층내의 해수의 거동은 복잡하다. 이러한 해저면 경계층의 거동을 파악하기 의한 접근 방법은 크게 둘로 나눌 수 있다. (중략)

• 전기의세계
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• v.42 no.3
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• pp.3-11
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• 1993

본 논문에서는 공장자동화, 우주로보트, 심해 자동차 등 여러 응용분야에서 새롭게 대두되는 고자치 시스템의 접근방법들과 시스템적인 개념들을 소개하였다. 이 분야에서의 주된 관심사는 상위계층의 기호적 모델과 하위계층의 도역학적(제어이론적) 모델간의 체계적 통합에 있다고 볼 수 있다. 즉, 프랜닝, 작동, 고장진단 및 수리 등과 같은 지능적 기능들을 제공할 수 있는 여러 계층의 동역학적 및 기호적 모델들의 유기적인 포괄 및 추상화에 의해서만 현존하는 다계층 제어 및 정보구조를 확장해 나갈 수 있을 것이다. 그러므로 고자치 시스템의 디자인을 위해서는 여러 분야의 팀단위의 노력이 경주되어야만 할 것이다. 디자인상의 난제로는 인간과 로보트간의 기능적 분할 그리고 상위화 하위간의 자동화를 위한 역할 분담등을 들 수 있다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.560-562
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• 2013

OIl & Gas의 시추 및 생산 해역이 연안 천수역에서 점차 심해로 이동하는 추세로서, 오프쇼어 지원선(OSV, Offshore Support Vessel)도 원근해 이동과 작업구역의 거친 해상조건에 대응하기 위해, 선박크기의 대형화, 고성능화, 대용량화, 저환경부하화, 그리고 안정성 및 신뢰성을 강력하게 요구하는 선박으로 수요가 증가하고 있다. 대 수심용 OSV의 종류와 기능, 시장현황과 발주추이, 그리고 관련 기술개발의 동향 등에 대한 조사 분석을 해봄으로서 국내 중소 조선소 및 기자재업체의 시장기회에 대한 고찰을 해 보았다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.1
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• pp.79-90
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• 2009

This paper presents the development of dynamically combined Typhoon generated surge-tide-wave numerical model which is applicable from deep to shallow water. The dynamically coupled model consists of hydrodynamic module and wind wave module. The hydrodynamic module is modified from POM and wind wave module is modified from WAM to be applicable from deep to shallow water. Hydrodynamic module computes tidal currents, sea surface elevations and storm surges and provide these information to wind wave module. Wind wave mudule computes wind waves and provides computed information such as radiation stress, sea surface roughness and shear stress due to winds. The newly developed model was applied to compute the surge, tide and wave fields by typhoon Maemi. Verification of model performance was made by comparison of measured waves and tide data with simulated results.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.1 no.2
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• pp.73-79
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• 1996

This study was conducted to investigate the faunal composition and distribution patterns of macrobenthic community in the deep sea sediments of the KODOS area, the northeastern Pacific Ocean during May 1996. Benthic animals were collected at 25 stations using a spade type box corer. Sediments were sieved through -.3 mm mesh screen. A total of 17 faunal groups in 9 phyla and 363 specimens were identified. Nematoda was the most abundant faunal group which accounted for 30.0% of total abundance. Other dominant faunal groups were foraminiferans (25.1%), harpacticoids (10.2%), xenophyophores (5.2%), and polychaetes (4.7%), Polychaeta was a typically dominant component of macrobenthic community in the study area except traditionally recognized meiofauna taxa. Mean occurrence number of faunal taxa was ca. 6 per 0.01 m$\^$2/, and mean density was estimated as 1,288 indiv./m$\^$2/. The abundance of whole fauna and that of each faunal group was highest at the surface layer of sediment, and decreased monotonously along the sediment depth; 98% of faunal abundance was found within 10 cm depth layer.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.4_1
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• pp.137-150
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• 1992

A complete solution, exact to second-order, for wave motion forced by a hinged-wavemaker of variable-draft is presented. A solution for a piston type wavemaker is also obtained as a special case of a hinged-wavemaker. The laboratory waves generated by a plane wave board are shown to be composed of two components; viz., a Stokes second-order wave and a second-harnomic free wave which travels at a different speed. The amplitude of the second-harmonic free wave is relatively large in shallow water and decreases to less than 10% of the amplitude of the primary wave in deep water. Wavemakers with relatively deeper draft (i.e., hinged near the bottom) generate the free waves of smaller amplitude in shallow and intermediate water depths than the wavemakers with shallow draft. However, the opposite is predicted by theory in deep water.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.06a
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• pp.158-160
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• 2009

선행되었던 연구인 실린더 슬릿형 소파블록 방파제에 대하여 실해역에서의 적용성을 평가하기 위하여 수치모델 해석을 통해 항내정온도를 분석하였다. 남해의 소규모 어항에 대해 파랑작용 평형방정식을 이용하는 SWAN 모델을 구성하고 수리모형실험에서 분석된 실린더형 슬릿 방파제의 투과율과 반사율을 도입하여 항내의 정온도의 변화를 불투과성 방파제와 비교하여 다루고 해수교환을 통한 해역수질환경의 개선 가능성을 예측해보았다. 수치실험은 한국해양연구원의 전해역 심해설계파 추정 보고서 II(2005)중의 심해설계파 제원을 사용하였으며, 대상해역의 1970년$\sim$2006년(37년간) 관측된 연최대 풍속자료를 이용하여 산정된 50년빈도 설계풍을 모델에 반영하였다. 대상 어항에서 서방파제에 주로 영향을 미치는 NNE계열의 파랑의 내습에 대한 분석을 수행하였으며, 그 결과 투과성구조물의 특성이 수치모형에서도 잘 재현하고 있음을 파악하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.4
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• pp.313-320
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• 1995

A numerical analysis on the wave deformation in the shallow water region is performed for the case of two intersecting wave trains of the same frequency on uniformly sloping beaches. This model is based on the consideration of wave energy balance and wave action conservation, and iteratively solved the set of conservation equations of both mass and horizontal momentum. Using the computed results, the wave deformations in accordance with the variation of the parameters luck as incident wave angie and wave height in deep water which influences the variation of wave hight and mean water level under the intersecting wave trains in the shallow water region. are considered.