• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.4
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• pp.269-276
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• 2012

Salinity distribution in estuary and tidal river is presented by many parameters including tidal forcing, river discharge and geographical effect. Understanding the characteristics of salinity structure is very important in the aspect of water-quality, ecological, and engineering viewpoint. Field measurement was carried out to study the distribution of salinity structure at 2 surface stations at Yeomha channel in the Han River estuary. The results of short- and long-term salinity change according to short and long tidal variability is investigated. For analyzing the axial salinity distribution at Yeomha channel, the salinity data from NFRDI is used in this study. The relationship between freshwater discharge and salinity distribution is represented through the nonlinear regression equation. The empirical equation for salt intrusion length scale, including tide, river discharge, and topographical effect is presented. As the comparison of empirical equation and existing data collected in study area, the characteristic of salt intrusion length and salinity distribution is changed by tide, fresh water, and geographical effect.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.157-164
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• 2003

Introduction of wave model, considered the effect of tide, wind and wave induced currents at the coastal waters of complex bathymetry, is a very important factor for most coastal engineering design and disaster protection problems. As the steady state spectral wave model could simulate depth induced wave shoaling and refraction, current induced refraction effect, steepness induced wave breaking, diffraction, wind wave growth, and wave-wave interaction that redistribute energy, this would support and compensate the gap in the real field of design where other wave models could not deal and cause wrong estimation. In this study, for that sense, we applied the spectral wave model t the large coastal waters near Gaduck Island where the Busan new port construction project is going on, for better understanding and analysis of wave transformation process. We also compared the simulation results with the calculated from the existing model. From such a trial of this study, we hope that broader and sager use of the spectral model in the area of port design and disaster prevention system come through in near future.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.2
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• pp.164-176
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• 2003

During summer, the DIN (dissolved inorganic nitrogen) and DIP (dissolved inorganic phosphate) observed in the Jindong Bay in the southern sea of Korea show much higher values in the inner area of the bay. In general, they have high values in the upper (0-1 m) and lower layers (8 m-bottom), but are relatively lower in the middle layer (1-8 m). These features in their distribution are examined using an ecosystem model with considering the wind, tidal current, horizontal gradient of water density and residual flow. The experiments were focused on how to influence nutrients associated with these conditions. In the experiment with tide-induced residual flow, the values of nutrients appeared lower than the observation, and were well corresponded to it when the effects of wind, tide-induced residual current and horizontal gradient of water density were additionally imposed. A statistical analysis identifies these results. This paper suggests that variation of nutrient in the Jindong Bay during summer should be seriously a(footed wind-driven current by the wind and density-driven current is induced by the horizontal gradient of water density as well as tidal current.

• Journal of Environmental Science International
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• v.7 no.2
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• pp.223-232
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• 1998

The spatial characteristics of stratification In Deukryang Bay were studded using observed data and analytical models. From the description of the density structure and its the potential energy anomaly (PEA) from observed data along longitudinal direction (from the mouth to head of the bays, we found that the stratification Intensity could be changed strongly by density current effect during the spring-neap tidal cycle, and depth variation. To find out density current effect for the formation of the stratification In detail, we Implemented a diagnostic approach by using the modified analytical model including density current, tidal current, surface heating and wind stirring. The model allowed for the observed similarities for the whole domain in the bay and increased tidal mixing efficiency value s up to 0.006-0.007 as compared to the results without density current effect. We found that the density current effect was also an important key factor In determining the formation of the spatial distribution of stratification.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.238-245
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• 2000

Separation strips are temporary joints to prevent crack due to stress induced by shrinkage. In this study, an analysis procedure considering separation strip is proposed to decide proper casting time of separation strip and cracking stresses of the example building slabs are calculated using this procedure. The result of the example high rise building shows that the percentage of cracking stress to the modulus of fracture is 43.4% when closing of separation strip are 30 days after placing the slab, so it is enough time for the separation strip in each floor to absorb the effects of shrinkage.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1997.10a
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• pp.90-94
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• 1997

조석파가 연안해역에 접근하게 되면 바닥마찰이나 수심의 감소에 따른 조위의 비선형 효과 및 육지와의 경계부분에서 발생하는 흐름의 곡률 등 여러 가지 요인에 의해 파의 진행에 변화가 야기되며 (Pugh,1987), 이에 따라 동일 천문조의 간섭에 의해 나타나는 overtide, 또는 2개 이상의 천문조간 상호 간섭에 의해 나타나는 compound tide와 같은 천해조가 발생하게 된다. (중략)

• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.1010-1013
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• 2010

한천 올리고당은 효소인 아가라제에 의하여 제조하였으며 제조에 있어서 효소의 농도, 반응 온도 등에 따른 최적 제조조건을 규명하였으며 한천 올리고당을 GPC로 분자량을 측정하였을 때 분자량이 약 4,200 Da이었다. 또한 한천올리고당의 항산화 작용 및 아질산 소거능을 측정한 결과 항산화 효과가 비타민 C보다는 약간 낮지만 68%정도의 비교적 높은 항산화 활성을 나타내었으며 한천 올리고당이 이산화질소의 과잉생성을 억제하여 정상레벨로 유지하는 것을 알 수 있었다.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1992.08a
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• pp.16-19
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• 1992

최근 컴퓨터의 발달과 함께 해안공학과 관련된 문제 해결에 있어서 처리속도에 관한 제약성은 점차 감소되고 있는 반면 정확도에 관한 관심이 높아지고 있는 추세이다. 현재까지 조석파 해석에서 가장 널리 쓰이고 있는 ADI(alternate direction implicit) 방법도 한 방향으로만 음해법적으로 차분하게 되므로 지형이 복잡한 곳에서는 소위 ADI효과라 불리는 바람직하지 않은 수치특성으로 인해 그 한계가 드러나고 있는 실정이다.(중략)

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.493-497
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• 2005

엄청난 자원의 매장고, 국가간의 대규모 교역을 가능케 한 항로, 어족자원의 공급원등으로서 인류의 생존과 번영에 일익을 담당하고 있는 바다는 인간의 증가하는 에너지 수요를 지속적으로 감당할 수 있는 무공해에너지의 보고로도 다가오고 있다. 그러나, 에너지 밀도가 타 에너지에 비하여 상대적으로 낮아 큰 규모의 에너지추출장치가 필요하다는 단점에도 불구하고, 대부분의 바다에서 하루에 두 번 씩 발생하는 조석현상을 이용하는 조력발전은 조석의 반복적이고 주기적인 특성 , 태양계가 존속하는 한 영구히 발생한다는 영속성, 현대과학과 관련기술의 진보 등으로 전 세계적으로 그 개발에 인류의 관심이 높아져 있다. 현재 조력발전소가 건설 중인 시화호는 포화상태에 있는 수도권에 공업용지를 공급하고 우량농지 조성으로 경쟁력 있는 농업을 육성하기 위하여 담수호로 조성되었으나,하수처리장 등 기초환경시설이 미비한 상태에서 인근지역으로부터 오염물질이 유입되어 수질이 악화되자 정부는 수질개선을 위하여 시화호를 해수호로 용도를 변경하였다. 본 논문에서는 조수간만의 차를 이용하여 무공해 전력을 생산하는 조력발전의 원리 및 최적발전량 산정기법과 높은 조수간만의 차로 조력개발적지로 유망한 서해안에 건설하게 될 시화호 조력발전소의 사업 및 기후변화협약 이행 시 기대효과 등에 대하여 논하고자 한다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.4
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• pp.335-343
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• 2016

The spatio-temporal distribution of jellyfish in Masan Bay was investigated in this study using a numerical model. First, a three-dimensional hydrodynamic model (POM) was constructed,taking into account residual flows, tides, temperature, salinity, and wind effects. A particle tracking model based on residual flow was then used to investigate the jellyfish present in Masan Port, referred to as the Heavy Industry and Gapo New Port in Masan. Jellyfish distribution was concentrated with maximum (2,533 individual) in the North Sea near Machang Bridge. Itcan be concluded that this concentration was due to multi-directional residual flows and topography effects. Residual flow currents are a dominant factor in understanding the aggregation of jellyfish, and this study used a numerical simulation of tide-induced residual currents, wind-driven currents and density currents in distinct cases to thoroughly address the topic. As a result, wind-driven currents (effect of the wind) was found to be superior to other components as an influence on the distribution of jellyfish near Machang Bridge and Modo in Masan Bay.