• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.4
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• pp.413-423
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• 2013

To elucidate the variation of species composition, biomass and length distribution of flatfishes by the period and region in the Uljin marine ranching area, bottom trawl survey was investigated at the six stations from Feb. 2008 to Dec. 2010. During the survey period, a total 4 families 17 species in the Pleuronectiformes, average 69,158 $ind./km^2$ and 5,625 $kg/km^2$ were identified, in 2008 appeared in 14 species, average 25,798 $ind./km^2$ and 2,333 $kg/km^2$ and in 2009 appeared in 13 species, average 102,360 $ind./km^2$ and 5,634 $kg/km^2$ and in 2010 appeared in 14 species, average 75,704 $ind./km^2$ and 8,632 $kg/km^2$. The individual dominant species, occupying over 10% of total individuals, was Pleuronectes herzensteini (20,811 ind., 30.0%), Hippoglossoides pinetorum (18,666 ind., 26.9%) and Glyptocephalus stelleri (13,499 ind., 19.4%) also the biomass dominant species, occuping over 10% of total biomass, was P. herzensteini (2,207 kg, 39.3%), Pleuronectes yokohamae (857 kg, 15.3%), H. pinetorum (761 kg, 13.5%), Kareius bicoloratus (677 kg, 12.1%). From the cluster and MDS analysis based on Bray-Curtis similarity matrix of fourth root transformed data of species number and individuals in the Uljin marine ranching area from Feb. 2008 to Dec. 2010 was divided into two different groups of the flatfishes community in 2008 and from Jan. to Apr. in 2009 and 2010 (Group A) and the pleuronectiform community in from May to Dec. in 2009 and 2010 (Group B). From the cluster and MDS analysis using the similarity of demersal organisms community among six stations, the Uljin marine ranching area was divided into two different groups of Group 1 (St. 1 and St. 3) and Group 2 (St. 2, St. 4, St. 5 and St. 6).

• Journal of Korea Port Economic Association
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• v.17 no.1
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• pp.159-180
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• 2001

The quantity of waste has been increased due to the increase in population and consumption after industrialization. Accordingly it caused the urban environmental problems, the lack of landfill and the pollution around the landfill. Thus, it is necessary to research the adequate alternative in the long-term. In case of Japan, areas and quantities of landfills at sea are more great than those of landfills in land. And investigating our condition, landfills of the metropolitan area in land are to be fully filled with wastes up to 2020 and be closed. In this research, construction of landfill sites at sea is suggested as the alternative waste disposal method and it is suggested that in our country, the suitable landfill sites of the metropolitan area are the regions around Jangbong-do Island and Muei-do Island. It is expected that the best way to transport wastes is to transport through Kyungin canal from the middle collection center to the lower Han River. Rough cost for construction of landfill at sea, if it is used for 50 years, is expected to be 2 trillion won and total time to construct the landfill is expected to be 10 years. Many studies concerning to this research proposal are to be performed so that construction of landfills familiar to environment are to be accomplished.

• Journal of Korean Port Research
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• v.12 no.1
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• pp.95-104
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• 1998

Water pollution in a semi-enclosed sea area such as a bay due to stagnancy of water has been a serious water environmental problem. Recently, some kinds of new methods to activate the tidal exchange between an inner bay and an outer sea area by control of a tidal residual current have been proposed. However, these methods have several problems, that is, I). deterioration in a natural view due to building of huge structures, II). increase of risk of navigation in case of a submerged structure, III). limition of sea area where a tidal current can be controlled and IV). difficulty in removing those structures in case of occurrence of an unexpected impact on water environment. In this paper, a new method is proposed, which can solve all the above problems, to purify water quality in a semi-enclosed bay by creation and control of a pattern of a tidal residual current. The tidal residual current is controlled by unsymmetric structures, which change the properties of resistance according to the direction of flow, arranged on the sea bottom. In this study, several numerical and hydraulic experiments of tidal current and particle-tracking for various arrangements of bottom roughness in a semi-enclosed model bay were carried out. As a result of experiments, it becomes clear that it is possible to generate a new tidal residual current and to activate a tidal exchange by only operation of bottom roughness arrangement.

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.5
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• pp.331-341
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• 2017

This paper presents the sea-trial results of Crabster CR6000 which is a deep-sea walking robot developed by KRISO in 2016. Crabster CR6000 is designed to inspect deep-sea environment rejecting the disturbance on the silent and calm abyssal area. The sea-trial was conducted at the East Sea and the Philippine Sea on December 2016. The Crabster CR6000 undocked successfully from the Shuttle after touchdown on the sea-bed and walked out on the soft sediment soil of the 4,743m seafloor at the fourth diving in the Philippine Sea. The advanced technologies and capabilities of CR6000 were verified from the operational and functional test conducted in the sea-trial. The experimental data acquired from the sea-trial were summarized and the first experience of the deep-sea walking robot was presented in this paper.

• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.475-485
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• 2011

Lake Sihwa has a very unique watershed environment, surrounded by industrial, urban and rural catchment area with different land use. The first flush phenomenon was investigated in 3 catchment area. 4TG, representing the industrial area, shows rapid discharges of highly concentrated pollutants during the early stages of a storm and it is indicating a strong first flush effect. At AS, representing the urban area, the pollutant concentration reached its peak approximately 2~3 hours after the start of storm, which is a strong first flush effect did not appear. JJB and MS represent the rural areas, the PEMC analysis results suggest that highly concentrated pollutants were discharged during the middle and latter stages of a storm, instead of early pollutant runoff due to the effects of rainwater runoff.

• The Journal of Bigdata
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• v.7 no.1
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• pp.89-97
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• 2022

Various efforts are needed to prevent accidents because ship collisions can cause various negative situations such as economic losses and casualties. Therefore, research to prevent accidents is being actively conducted, and in this study, new leading indicators for preventing ship collision accidents is proposed. In previous studies, the risk of collision was expressed in consideration of the distance between ships in a specific sea area, but there is a disadvantage that a new model needs to be developed to apply this to other sea areas. In this study, the density-based ship domain DESD (Density-based Empirical Ship Domain) including the environment and operating characteristics of the sea area was defined using AIS (Automatic Identification System) data, which is ship operation information. Deep clustering is applied to two-dimensional DESDs created for each sea area to cluster the seas with similar operating environments. Through the analysis of the relationship between clustered sea areas and ship collision accidents, it was statistically tested that the occurrence of accidents varies by characteristic of each sea area, and it was proved that DESD can be used as a leading indicator of accidents.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.1
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• pp.1-12
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• 2024

In this study, we analyzed the water temperature variability in the sea area of the Korean Peninsula in August, before and after the typhoon inflow through Typhoon Soulik, the 19th in 2018 that turned right around the Korean Peninsula and passed through the East Sea, and Typhoon Bavi, the eighth in 2020 that advanced north and passed through the Yellow Sea. The data used in this study included the water temperature data recorded in the real-time information system for aquaculture environment provided by the National Institute of Fisheries Science, wind data near the water as recorded by the automatic weather system, and water temperature data provided by the NOAA/AVHRR satellite. According to the analysis, when typhoons with different movement paths passed through the Korean Peninsula, the water temperature in the East Sea repeatedly upwelled (northern winds) and downwelled (southern winds) depending on the wind speed and direction. In particular, when Typhoon Soulik passed through the East sea, the water temperature dropped sharply by around 10 ℃. When Typhoon Bavi passed through the center of the Yellow Sea, the water temperature rose in certain observed areas of the Yellow Sea and even in certain areas of the South Sea. Warmer water flowed into cold water regions owing to the movement of Typhoon Bavi, causing water temperature to rise. The water temperature appeared to have recovered to normal. By understanding the water temperature variability in the sea area of the Korean Peninsula caused by typhoons, this research is expected to minimize the negative effects of abnormal climate on aquaculture organisms and contribute to the formulation of damage response strategies for fisheries disasters in sea areas.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2005.11a
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• pp.219-221
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• 2005

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.949-950
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• 2005

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.189-191
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• 2010