• Water for future
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• v.33 no.S1
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• pp.319-340
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• 2000

• Proceedings of the Korea Water Resources Association Conference
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• 2000.02b
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• pp.319-340
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• 2000

• Journal of Ocean Engineering and Technology
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• v.6 no.1
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• pp.19-28
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• 1992

The motion of a cylindrical object resting on shallow seabed due to wave forces and soil friction is studied. Given environmental conditions such as wave characteristics and seabed soil properties, the equations of motion are derived and the corresponding reponses of the cylinder in two dimensional plane, i.e., translational and rotational displacements, accelerations, are calculated. The motion is substantially restrained by the penetration of a cylinder into seabed and the parametric study focuses on finding out a minimum penetration depth which makes the cylinder motionless.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.4
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• pp.83-93
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• 1983

A non-linear numerical tidal model of the Yellow Sea and the East China Sea is used to derive the mean and maximum bed stress the mean and maximum transport potential on the continental shelf. It has provided a preliminary assessment of relation between sediment transport paths and the mean and maximum bed stress distribution determined from the numerical model.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1994.07a
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• pp.106-110
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• 1994

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.79-80
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• 2001

저층트롤 어업은 주로 고가의 저서성 어족을 대상으로 조업이 이루어지고, 어구의 구조나 규모가 다양하며 발줄은 어구의 접지성을 유지하는 기능과 함께 어군을 망구에 구집 하는 역활을 한다. 저층 예망어구는 해저를 소해 하면서 예방하기 때문에 해저와의 마찰 저항이 많을 뿐만 아니라 뻘을 뜨거나 장애물에 걸리는 사고가 발생하기도 하여, 어획성능에도 많은 영향을 받는다. 이에 대한 연구로써, 독일에서는 빔 트롤의 체인의 형태에 따른 모형 트롤어구의 역학적 특성을 실험(1997, Uwe Richter)한 바가 있고, 일본에서도 발줄의 형상에 관한 연구(1992,Fuwa)가 있다. (중략)

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.2 no.3
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• pp.162-181
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• 1990

The hydrodynamic model is used to analyse the sea surface elevations derived from the SEASAT altimetry over the Yellow Sea and the East China Sea. Periods of significant atmospheric disturbances during the SEASAT mission are selected for this study. These includes periods of July 28-August 2 and August 18-21. Meteoroloeical forcing functions, which are needed for the sea model, are derived by a 2-dimensional grid that is governed by a set of theoretical and empirical meteorological relations over the study area. Ocean tides in this area are known to be significant and introduce a large spatial and time variability in the sea surface elevation. Consequently major tidal constituents of M$_2$, S$_2$, $K_1$ and $O_1$ are included in the computation. With some knowledge of other known sea surface phenomena e.g.(body tide, loading tide), the time-dependent sea surface variation is predicted to com-pare statistically with the satellite altimetric measurements and to achieve the objective of ocean bottom friction study. From a total of 10 SEAST orbit tracks, a friction coefficeint was found ranging from 0.0023 to 0.0027.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.10 no.1
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• pp.18-26
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• 1998

In order to find out hydrodynamic changes due to huge complex constructions in the Keum River Estuary, two-dimensional finite element model is applied. Model results show that gate closing of the estuary dam yields tide amplifications at Kunsan Inner Port to 17 cm and 6 cm of M$_2$ and S$_2$, while 5 cm and 3 cm of amplification at Kunsan Outer Port. Tidal currents in the main channel due to stepwise flow-guide dikes construction have been simulated and show that dynamic equilibrium bottom shear stress is 0.4 N/m$\^$2/ on this Keum River Estuary. Sedimentation rates R have correlation with maximum bottom shear stress (equation omitted), R=-0.37-0.40 ln $\tau$.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.16 no.4
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• pp.224-232
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• 2004

Sedimentation changes related with bottom shear stress attenuation at JangHang channel in the Keum River Estuary, where several huge coastal constructions including an estuarine dam have been conducted for last 2 decades, were evaluated for 7 cases to figure out passage hindrance through the channel by a hydrodynamic model using hind-casting technique from 1988 to 2000 at every 2 years interval. Due to the construction of Keum River Estuary Dam, the maximum bottom shear stress rapidly lessened to $0.2-0.6N/m^2$ compared to$1-2N/m^2$ in natural status. Especially it marks below the critical shear stress of $0.4N/m^2$ resulting in severe siltation in the channel just after the closing of dam gates in 1994. It is concluded that the dam may block the tidal energy propagation to upstream and directly results in sedimentation environment in front of dam site. It is also revealed that at least 20% of passage hindrance of small fishing boats through the channel could be counted due to sedimentation by analysis of predicted mean spring tides.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.2
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• pp.73-78
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• 2010

Wave energy is dissipated mainly by friction on the seabed until the waves reach the surf zone. Many researchers have investigated the mechanism of wave friction and the bottom shear stress induced by wave motion at a certain point is now well estimated by introducing the wave friction factor related to the near bed velocity given by linear wave theory. The variation of wave energy or wave height over a long distance can be, however, estimated by an iteration process when the propagation of waves is strongly influenced by bed friction. In the present study simple semi-theoretical equation has been developed to compute the variation of wave height for the condition of wave propagation on a constant beach slope. The ratio of wave height is determined by the product of shoalng factor and wave height friction factor (frictional wave energy dissipation factor). The wave height estimated by the new equation is compared with the wave height estimated by the solution of numerical integration for the condition that the waves propagate on a constant slope.