• Journal of Advanced Marine Engineering and Technology
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• v.32 no.6
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• pp.989-996
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• 2008

Recently, a few types of fish-cage in open sea are researched. This fish-cage has to operate monitoring system for keeping an optimum living condition for fish. The most efficient monitoring system is WVMS(Wireless Vision Monitoring System) for fish-cage in open sea. WVMS should be able to transmit video signal and communicate with each controller. So. it needs to be based on WLAN(Wireless LAN) which has characteristic of higher transfer-rate, In this paper, we propose a structure of WVMS using WLAN equipments for maritime environment and prove its effectiveness. We present the propagation loss model of WVMS's communication channel. measured by field test, and discuss its validity compared with the predictive value based on the Friss propagation model and Plane earth reflection model. We present the number of frames that is received from WLAN modem connecting with underwater-camera in field test spots. As a result, we confirmed that proposed WVMS is suitable for maritime environment and it is possible to be applied to fish-cage in open sea on 'seogwipo'.

• Journal of Environmental Science International
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• v.9 no.1
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• pp.19-25
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• 2000

As the tideland reclamation is done on a large scale these days, construction work is active in the coastal areas. Facilities in the coastal areas must be built with the tide characteristics taken into consideration. Thus the tide characteristics affect the overall reclamation plan. The analysis of the tide data boils down to a harmonic analysis of the hourly changes of long-term tide data and extraction of unharmonic coefficients from the results. Since considerable amount of tide data of the West Coast are available, the existing data can be collected and can be used to obtain the temporal changes of the tide by being fitted into the tide prediction model. The goal of this thesis lies in assessing whether the mean sea level used in the field agrees with the analysis results from the long-term observation data obtained with their homogeneity guaranteed. To achieve this goal, the research was conducted as follows. First the present conditions of the observation stations, the land level standard, and the sea level standard were analyzed to set up a time series model formula for representing them. To secure the homogeneity of the time series, each component was separated. Lastly the mean sea level used in the field was assessed based on the results obtained form the analysis of the time series.

• Journal of The Geomorphological Association of Korea
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• v.20 no.3
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• pp.41-53
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• 2013

This research was carried out to classify erosion shapes and sea-cliff erosion rates were estimated through periodic field survey in Dundu-ri, Anmyeondo. Based on the results of field measurements using the datum-point, the annual sea-cliff erosion rate was estimated about 25~102cm/yr by point. The erosion rate gradually increases from spring to summer, but tends to decrease slightly in autumn. Specifically, the erosion rate between June and July indicated a rather decreasing trend, but showed a sharp increase between July and September. This was attributed to erosion that proceeds more rapidly than during other periods due to severe rainstorms in summer that had a direct impact on the study area as well as storm surges caused by hurricanes. Afterwards, the sea-cliff erosion rate gradually decreased in autumn, but reflected an increasing trend again from December to January. This was attributed to the mechanical weathering that actively progresses as bed rocks on the sea-cliff undergo repeated freezing and thawing in winter. The seacliff in Dundu-ri is divided into three types according to the erosion shape. First, Type A is observed in the sea-cliff composed of the same bed rocks and hard rock stratum. Second, Type B is found in the sea-cliff with a relatively gentler slope compared to Type A, since weathering material including soil is formed on the surface of the sea-cliff consisting of the same bed rocks and hard rock stratum. Lastly, Type C is observed in the sea-cliff where hard rock stratum is mixed with soft rock stratum. In this case, the soft rock stratum slumps and erodes first by precipitation and wave energy, followed by additional slumping of the exposed hard rock stratum.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.4
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• pp.195-204
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• 2009

In order to estimate sea surface current fields in the East Sea, we examined characteristics of mean dynamic topography (MDT) fields (or mean surface current field, MSC) generated from three different methods. This preliminary investigation evaluates the accuracy of surface currents estimated from satellite-derived sea level anomaly (SLA) data and three MDT fields in the East Sea. AVISO (Archiving, Validation and Interpretation of Satellite Oceanographic data) provides a MDT field derived from satellite observation and numerical models with $0.25^{\circ}$ horizontal resolution. Steric height field relative to 500 dbar from temperature and salinity profiles in the East Sea supplies another MDT field. Trajectory data of surface drifters (ARGOS) in the East Sea for 14 years provide another MSC field. Absolute dynamic topography (ADT) field is calculated by adding SLA to each MDT. Application of geostrophic equation to three different ADT fields yields three surface geostrophic current fields. Comparisons were made between the estimated surface currents from the three different methods and in-situ current measurements from a ship-mounted ADCP (Acoustic Doppler Current Profiler) in the southwestern East Sea in 2005. For offshore areas more than 50 km away from the land, the correlation coefficients (R) between the estimated versus the measured currents range from 0.58 to 0.73, with 17.1 to $21.7\;cm\;s^{-1}$ root mean square deviation (RMSD). For coastal ocean within 50 km from the land, however, R ranges from 0.06 to 0.46 and RMSD ranges from 15.5 to $28.0\;cm\;s^{-1}$. Results from this study reveal that a new approach in producing MDT and SLA is required to improve the accuracy of surface current estimations for the shallow costal zones of the East Sea.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.3
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• pp.627-635
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• 2017

Sea level rise caused by climate change has become a global issue. Sea level rise seems to be an important factor of the research for coastal areas as it affects topography and vegetation of coasts and especially for the plan of coastal wetlands restoration which needs to be carried out for a long term, it has to be considered sufficiently. The coastal wetlands in Korea was damaged by the land reclamation project but recent concerns on the restoration have increased as its value is evaluated highly. Suncheon Bay had also reclaimed from wetlands to rice field once however this site is very active for restoration nowadays. This study estimated an effect according to sea level rise by 2100, reappearing the none dike condition of Suncheon Bay so that it can be taken account of a future plan of wetland restoration. The Sea Level Affecting Marshes Model(SLAMM) was selected as predicting model. The input data such as DEM(Digital Elevation Model), slope, wetlands category, sea level rise senario, tidal range and accretion rate was applied for the simulation. The results showed a decrease in tidal flat, an increase in sea area and a change of the rice field to transitional salt marsh consistently by 2100. These results of this study could be used as baseline data in the future plan of ecological restoration in Suncheon Bay.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.6
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• pp.563-567
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• 2003

Various bacterial strains were isolated from rice field ditch water, and their seaweed degrading activities were investigated. They were incubated in a liquid medium of sea tangle (Laminaria iaponica) and sea mustard (Undaria pinnatifida) powder for 3 weeks. Ratios of reduced sugar to total sugar of the liquid medium were measured once a week. Ratios of reduced sugar to total sugar of 27A311, 27C221 27A111 and 27B121 strains were highest. Accordingly, these four strains were incubated in 3 different liquid media of sodium alginate, sea tangle powder, and sea mustard powder for 3 or 4 weeks. The ratios of reduced sugar to total sugar and cell growth were measured once a week. Cell growth was higher in 27A111 and 27C221. Ratios of reduced sugar to total sugar was higher for 27C221 in the liquid mediums with sodium alginate and sea mustard powder, and for 27A111 in the liquid medium with sea tangle powder.

• Journal of Ocean Engineering and Technology
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• v.19 no.1 s.62
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• pp.14-19
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• 2005

As a basic study for establishing the input conditions of a forecasting/estimating model, used for deep-sea water drainage to the ocean, this study was carried out as follows: 1) estimating the amount of river discharge and pollutant loads into the developing region of deep sea water in the East Sea, Korea, 2) a field observation of tidal current, vertical water temperature, and salinity distribution, 3) 3-D numerical experiment of tidal current to analyze the physical oceanographic status. The amount of river discharge flowing into this study area was estimated at about $462.7{\times}103 m\^3/day$ of daily mean in 2002. Annual mean pollutant load of COD, TN, and TP were estimated at 7.02 ton-COD/day, 4.06 ton-TN/day, and 0.39 ton/day, respectively. Field observation of tidal current normally shows 20-40cm/sec of current velocity at the surface layer, and it decreases under 20cm/sec as the water depth increases. We also found a stratification condition at around 30m water depth in the observation area. The differences in water temperature and salinity, between the surface layer and the bottom layer, were about 18 C and 0.8 psu, respectively. On the other hand, we found a definite trend of 34 psu salinity water mass in the deep sea region.

• Journal of Environmental Science International
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• v.14 no.10
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• pp.911-917
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• 2005

A comparison between the estimated chlorophyll a from OSMI, the SeaWiFS and the chlorophyll a measured from the research cruises of National Fisheries Research and Development Institute was made. The updated empirical algorithm for calibrating and validating of the estimated chlorophyll a in the East China Sea was formulated by relationship between the estimated chlorophyll a and the field one. The relationship between the chlorophyll a and the band ratio(nLw490/555) was still highest in the OSMI data after launching of KOMPSAT satellite. The distributions of OSMI chlorophyll a were compared with those of sea surface temperature, zooplankton biomass, and catch amounts of the Pacific mackerel in the East China Sea. In case of the relationships in specially winter seasons of 2002 and 2004, the zooplankton and the fish were totally depended on the distributions of SST than those of chlorophyll a.

• Journal of the Korean Society of Earth Science Education
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• v.8 no.2
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• pp.128-138
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• 2015

The purpose of this study is to examine potential as a geological field course of Odongdo located to the east of Yeosu city, Korea. The total area and the height from the sea level of Odongdo is about 0.13km2 and 42m, respectively. Odongdo area belongs to the Hallyeohaesang National Marine Park, and is famous for rock scenery in the rocky coast and living of rare plants. For this study, diversity of geomorphology and geology was investigated at the sites called as dragon cave, windy area, seal rocks, sunrise viewing platform, second seashore rocks and first seashore rocks along the coast of Odongdo. The results of this study are as follows: A lot of geomorphological and geological resources like sea cliff, sea cave, strata, various sedimentary rocks(conglomerate, sandstone, mudstone), andesite, fault and examples of rock weathering were found in the rocky coast of the study area. These field resources are pertinent to the field work materials for the teaching and learning of geology units in elementary school science. Odongdo is to be recommended as a site of outdoor geological field course for the elementary school students inhabited in Yeosu city and neighborhood area because each site of the rocky coast in this study area has various field work materials and the wide space for observe activities, and is equipped with the facilities as a trail for rock observation.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.5
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• pp.179-186
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• 2021

We need measures that can come up with alternative about fishery living zone and enhance local acceptance for responding to the increase in the proportion of renewable energy production and construction of 12GW Offshore wind power according to Korea's Renewable Energy 3020 initiative and Korean-version New Deal. In this study, We suggest that differentiation plans of co-location model in connection with offshore wind power generation suitable for the East Sea. The East Sea is an optimal site for building of a floating offshore wind power generation(FOWPG) field. It is expected that economic effects like energy production, aquatic resource development and tourism industrialization by farming bluefin tuna which is high valued fish and suitable for offshore aquaculture on public waters in FOWPG field. And we can confirm that budget reduction, smart management by sharing operation management technology and increase in fishermen income.