• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.1
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• pp.25-32
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• 2014

Offshore wind power structures are subject to coastal hydrodynamic loading such as wind and wave loads. A considerable number of turbines have been installed in Europe, but so far none in Korea. Interest in offshore wind energy is growing in Korea, and it is expected that projects will reach the design stage in the near future. This paper discusses the level of structural reliability implied by the design rules of ABS(2010, 2013) and IEC(2009). Metocean conditions in 4 Korean seas(Gunsan, HeMOSU 1, Mokpo, Jeju) were used in the calibrations to calculate the aerodynamic and hydrodynamic loads as well as the structural responses of the typical designs of offshore wind turbines. Due to the higher variability of the wind and wave climate in hurricane-prone areas, applying IEC strength design criteria in combination with Korea west sea conditions could result in a design with much lower reliability index than what is anticipated from a design in European waters. To achieve the same level of safety as those in European waters, application of ABS 100 year design standards are recommended. Level-1 reliability-based design suitable for the Korean sea state conditions should be introduced because the IEC standards does not consider the typhoon effects in depth and the ABS standards is a WSD design method. In addition, the design equation should be established based on the statistical characteristics of the wind and wave loads of the Korean sea areas.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.1
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• pp.101-108
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• 2011

The purpose of salinity intrusion due to numerical simulation is analaysis for saline intrusion to the upstream channel in Nakdong River Estuary Barrage(NREB) to get enough fresh water. Conditions that occur salinity intrusion affect by tidal distribution at seas, so salinity concentration changes according to tidal phenomenon. Making this connection cleary can help preventing salinity intrusion. In this study, estimating salinity intrusion to the upstream channel in NREB using EOMSED model, we reexamine NREB's existence. Comparison is also made with observing data. In result, when inflow discharges at $75m^3/s$ is more similar with respect to observing data than $130m^3/s$ at ECOMSED model. Thus, estimations are more precise at little discharges than lots of discharges.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.4
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• pp.211-222
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• 2009

The fisheries resources by a set net in the coastal waters off Neungpo, Goeje Island from 2003 to 2004 were studied to determine species composition and catch variation. The main fishing period by a set net were from April to December in 2003 and from May to December in 2004. A total weight of 48 species caught through the survey period was 540,688.0kg. Most of them were 44 species of fishes and a few were 4 species of cephalopods. Dominant species was Trachurus japonicus accounting to 57.5% in total catch. Sub-dominant species were Trichiurus lepturus(12.9%), Engraulis japonicus(10.6%), Scomber japonicus(6.9%), Clupea pallasii(4.5%), Todarodes pacificus(2.8%) and Parapristipoma trilineaturm(1.3%). The remnant species showed a low catch, indicating the catch had less than 1% in total, respectively. T. japonicus and T. lepturus were caught throughout the survey period, but C. pallasii, Gadus macrocephalus, Oncorhynchus keta in low temperature season and Thunnus obesus in high temperature season. The fishing ground temperature was 11.7-24.0${^{\circ}C}$ in range and the catch by a set net was higher in autumn than in spring and in summer with the variation of fishing ground temperature. The annual catch by a set net was much higher in 2004 than in 2003 due to high temperature(>17${^{\circ}C}$) and the recruitment of T. japonicus from offshore seas. Therefore we concluded that the catch of Neungpo fishing ground by a set net was highly related to the variation of T. japonicus catch with fishing ground temperature.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.4
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• pp.529-541
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• 2015

We examined the species composition and community structure of demersal fish in the middle and southern coastal waters of the East Sea of Korea by surveying a commercial Danish seine fishery from 2010 to 2013. We considered the waters north of $37^{\circ}N$ as middle and those south of $37^{\circ}N$ as southern waters. A total of 79 demersal fish species belonging to 18 families were collected. Of these, 59 species (77.6%) inhabited only the East Sea as opposed to the West and South Seas of Korea, and most were resident species. The species and biomass were similar between the two portions of the study area. The sandfish Arctoscopus japonicus (78.0%) and the blackfin flounder Glyptocephalus stelleri (65.1%) were the most common species and accounted for the most biomass in the middle and southern waters, respectively. Fish were most abundant at shallow depths (50-100 m) in the middle portion of the East Sea. Using a cluster analysis, we divided the species composition and community structure at the sampling stations into three groups: middle portion (group A), deep area of the southern portion (group B), and shallow areas of the southern portion (group C). A. japonicas and G. stelleri were dominant in groups A and B, while G. stelleri and Clupea pallasii were dominant in group C.

• Journal of the Korean Society of Marine Environment & Safety
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• v.9 no.2
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• pp.65-72
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• 2003

Oceanic conditions of the Tsushima Warm Current (TWC) region in the southern area of the East Sea (Japan Sea) are examined using data obtained from a CREAMS (Circulation Research if the East Asian Marginal Seas) cruise in June 1996. In 1990s, a lower temperature appears in 1996 and in this period, two branches of the TWC exist and the first branch of the TWC flows inshore of the Japanese coastal region compared to that in the other years, especially in the shallower water layer at depth less than about 200 m. The TWC cored with the higher salinity (>34.6 psu) is clearly observed over the continental shelf in the Japanese coastal region and offshore and identified by geostrophic calculation. Intrusion of the TWC into the East Sea through the Korea Strait (the Tsushima Strait) makes the density structure in the water column change and the water mass in the TWC region is unstable based on Brunt­Vaisala frequency.

• Journal of Fisheries and Marine Sciences Education
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• v.6 no.1
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• pp.77-91
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• 1994

The Yellow Sea and the East China Sea are the most important fishing grounds for the fishing industry of Korea, China and Japan which are major coastal states of these Seas. But the fishery resources in these fishing grounds are almost exhausted and also the sea region is seriously polluted. Accordingly an international joint countermeasure is necessary to recover the fishery resources and to keep the fishery a continuous industry. The authors inspected the existing fishery policies and international fishery relationship of the three coastal states, and suggested rational conservation and management regime of the fishery resources in these sea regions. 1. At present the legal status of the sea region beyond territorial sea is the high sea, for that reason the international cooperation is urgently needed to establish common regime for conservation and management of the fishery resources. 2. A series of scientific research on ecological system of fishery resources must be carried out in the sea region first of all for that purpose. 3. The existing Korea-Japanese Fishery Agreement and Sino-Japanese Fishery Agreement should be reformed to coincide with the new legal order of the UNLOS Convention, and the Sino-Korean Fishery Agreement should be concluded newly on the identical line. 4. As a conclusion, a joint conservation and management regime through a regional fishery organization or a individual conservation and management regime through the promulgation of exclusive economic zone by each state can be suggested to resolve the fishery resources conservation problem in the Yellow Sea and the East China Sea.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.17 no.4
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• pp.243-258
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• 2005

A fully-nonlinear two-dimensional dynamically interfaced nested tidal model has been developed with improved efficiency, usability, relocatability and also adopting different time steps for economizing computational times, which is based on two-dimensional tidal model of Choi(1990) with resolution of $1/15^{\circ}$ inlatitude by $1/12^{\circ}$ in longitude covering the whole Yellow and East China Seas continental shelf. To illustrate the validity and applicability of the present model, numerical model experiment was carried out for tidal distribution in the Yellow Sea and the East China Sea emphasizing the Saemangeum area with enhanced grid system. The results from comparison with observed value showed that the present model gives reasonable agreement. The present modeling system is a relocatable tide forecasting system designed to predict tides at any location within the Yellow Sea and the East China Sea continental shelf sea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.63-66
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• 1985

Phytoplankton (microplankton and nannoplankton) biomass as chlorophyll-a concentrations ana ratios of nannoplanktons ($size<60{\mu}m$) to total phytoplanktons ($size<300{\mu}m$) were measured in the coastal waters of Korea in fall, 1983. Chlorophyll-a concentrations of total phytoplankton ranged from 0.202 to 1.350 $mg/m^3$ with a mean and standard deviation, $0.597{\pm}0.287\;mg/m^3$, Chlorophyll-a concentrations of the nannoplankton ranged from 0.100 to $0.855\;mg/m^3$ with a mean and standard deviation, $0.372{\pm}0.201\;mg/m^3$, and it accounted for 25.4 to $83.3\%$ with an average $62.2\%$ to total phytoplankton biomass as chlorophyll-a concentrations. The amounts of chlorophyll-a concentrations of total phytoplankton in the water column below the surface area of $1m^2$ varied from 16.12 to $17.67\;mg/m^2$ with a mean $17.01\;mg/m^2$.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.11 no.1
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• pp.7-19
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• 1999

The energy transfer between sea-wave components by way of nonlinear wave-wave interactions plays a central role in spectral evolution. Since huge calculation time is required to exact computation of the resulting Boltzmann integral, however, the exact nonlinear energy transfer has not been directly introduced into operational wave models. Thus, effective calculation methods were examined in the present study which exploit the scale property of a scattering coefficient and the detailed balance of interactions. The improved Webb's method (IWM) has inherent stability because singularities degenerate into a negligible point. The improved Masuda's method (IMM) makes a quasi-analytical treatment of the inherent singularities and requires only 1.3 seconds of computer time via Pentium 300MHz processor. The IMM is, therefore, projected to be very useful for theoretical researches in spectral evolution with fetch- or duration-limited situations.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.11 no.1
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• pp.20-33
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• 1999

The evolution of deep-sea waves is driven by energy input from wind, nonlinear energy transfer between wave components, and dissipation through whitecaps. A comparative study was implemented by the use of two wave models in which only the computation methods of nonlinear wave-wave interactions are different from each other. It was reaffirmed that the nonlinear interaction plays a central role in such phenomena that occurred during the spectral growth of wind-seas as down-shift of the spectral peak frequency, overshoot, undershoot, and formation of self-similar spectrum. Specifically, the directional distribution at high frequencies develops into bimodal form, which is attributed to the nonlinear interactions. As saturation stage is reached, spectral density at high frequencies becomes proportional to negative 4 power to the frequency. Perturbations introduced into the spectrum quickly vanished through the actions of the self-similar mechanism. Thus, the nonlinear transfer has important contribution to the stability of numerical ocean wave models.