• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.272-277
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• 2005

Initial mixing characteristics in near field regions were analyzed by FLOW-3D, for analyzing mixing behavior of submerged discharge from freshwater lake in sea water. FLOW-3D model was applied to the region near Geum-ho dike for its verification. Simulation results from FLOW-3D were compared to the observed data for the verification periods. FLOW-3D showed resonable prediction results compared to the observed data, except underestimation in area near outfall. Particularly, FLOW-3D showed a good prediction for movement of buoyancy jets. In addition, FLOW-3D model was applied to the region near Saemangeum dike, which is to be constructed in near future. It was expected that the results of model application to Saemangeum area could provide substantial information in planning submerged discharge facilities. Based on the model applications to Saemangeum area, it was recommended that outfall should be located to the distance which gave an enough depth of outfall from water surface.

• Journal of the Korean earth science society
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• v.31 no.3
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• pp.214-224
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• 2010

Gravity and Magnetic survey data were analyzed to investigate the geophysical characteristics and regional geological structures of the southwestern Yellow Sea. The set of data about the southwestern part of the Yellow Sea in Korea was one collected by the Korea Ocean Research and Development Institute (KORDI) in 2003, 2004, and 2005. The Yellow Sea has a few basins and the study area also includes parts of the Heuksan Basin and the East China Sea Basin. The bathymetry of the study area ranges from about ?40 m southwestward near China to about 150 m northeastward near Korea. The bathymetry has the gentle rise and fall and the smooth slope. The gravity anomalies, from sea surface gravity and satellite gravity data, reflect the basement rocks rather than the smooth bathymetry. The gravity anomalies are higher on Northeastern part of the study area and lower over the South of the Heuksan Basin. The analytic signal from the Bouguer anomaly shows higher anomalous zones near the boundaries of the basins. The magnetic anomalies and the analytic signal, from the magnetic data, suggest that the complex anomalies on the Northern part are attributed to the volcanic intrusions and that the smooth patterns in the Southern part are based on the lack of the intrusions. The power spectrum analysis of the Bouguer anomalies and the magnetic anomalies indicate that the depth to the Moho discontinuity varies from about 30.2 to 28.3 km and that the depths of the basement rocks and the Eocene discontinuity range from about 8.4 to 8 km and from about 1.5 to 1.7 km, respectively. The inversion of the Bouguer anomaly shows that the Moho depth to the Western part of the study area near China is slightly deeper than the Eastern part near Korea. The result of 2-D gravity modeling has a good coherence with the results of the analytic signal, the power spectrum analysis, and the inversion.

• The Journal of Engineering Geology
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• v.9 no.1
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• pp.17-29
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• 1999

There are three major processes to impact the groundwater flow near underground storage caverns in the coastal area; effect of topography, effect of sea water intrusion, and effect of excavation. In this paper, the effects of three items were numerically studied to identify the major cause for altering the flow pattern. It turned out that the excavation is the most significant effect on the groundwater flow system. The groundwater pressure distributions and consequent groundwater pathways were significantly altered near the openings. By increasing the groundwater pressures from water curtain holes, the potential leakage of storage cavern was properly prevented

• Ocean and Polar Research
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• v.24 no.4
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• pp.369-389
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• 2002

CTD data taken in the Ulleung Basin between 1996 and 2001 are analyzed to understand the hydrography around Dokdo. Major features occurring in the Ulleung Basin such as the path variability of the East Korean Warm Current (EKWC), the location and size of the Ulleung Warm Eddy (UWE) and the position of the Offshore Branch along the Japanese coast all influence the hydrography around Dokdo. The Dokdo area frequently lies in the eastern part of the meandering EKWC and the UWE that results in a filting of isolines sloping upwards to Dokdo in the Ulleung Interplain Gap (UIG) between Ulleungdo and Dokdo. Subsurface water near Dokdo then becomes colder and less saline than water near Ulleungdo. Two cases that are opposite to this general trend are also identified when the Dokdo area is directly affected by the EKWC and by a small scale eddy ffd by the Offshore Branch. High salinity cores and warm waters are then found near Dokdo with isolines sloping upwards to Ulleungdo. Freshening of the East Sea Intermediate Water was observed in the UIG when neither the EKWC nor the UWE was developed in the Ulleung Basin during June-November 2000.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.3
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• pp.669-676
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• 2018

The Geostationary Ocean Color Imager(: GOCI) detects the sea fog at a high horizontal resolution of $500m{\times}500m$ using the Rayleigh corrected reflectance of 8 bands. The visible and the near infrared waves strongly reflect the characteristics of the earth surface, causing errors in cloud and fog detection. A threshold of the Band7 reflectance was set to detect the sea fog entering the land. When the region on which Band4 reflectance is larger than Band8 is determinated as cloud, the error over-estimated as sea fog is corrected by comparing the average reflectance with the surrounding region. The improved algorithm has been verified by comparing the fog images of the Cheollian satellite (COMS: Communication, Ocean, and Meteorological Satellite) as well as the visibility data from the Korea Meteorological Administration.

• Steel and Composite Structures
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• v.51 no.2
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• pp.153-172
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• 2024

Due to the fast development of constructions in recent years, there has been a rapid consumption of fresh water and river sand. In the production of concrete, alternatives such as sea water and sea sand are available. The near surface mounted (NSM) technique is one of the most important methods of strengthening. Aluminum alloy (AA) bars are non-rusting and suitable for usage with sea water and sand concrete (SSC). The goal of this study was to enhance the shear behaviour of SSC-beams strengthened with NSM AA bars. Twenty-four RC beams were cast from fresh water river sand concrete (FRC) and SSC before being tested in four-point flexure. All beams are the same size and have the same internal reinforcement. The major factors are the concrete type (FRC or SSC), the concrete degree (C25 or C50 with compressive strength = 25 and 50 MPa, respectively), the presence of AA bars for strengthening, the direction of AA bar reinforcement (vertical or diagonal), and the AA bar ratio (0, 0.5, 1, 1.25 and 2 %). The beams' failure mechanism, load-displacement response, ultimate capacity, and ductility were investigated. Maximum load and ductility of C25-FRC-specimens with vertical and diagonal AA bar ratios (1%) were 100,174 % and 140, 205.5 % greater, respectively, than a matching control specimen. The ultimate load and ductility of all SSC-beams were 16-28 % and 11.3-87 % greater, respectively, for different AA bar methods than that of FRC-beams. The ultimate load and ductility of C25-SSC-beams vertically strengthened with AA bar ratios were 66.7-172.7 % and 89.6-267.9 % higher than the unstrengthened beam, respectively. When compared to unstrengthened beams, the ultimate load and ductility of C50-SSC-beams vertically reinforced with AA bar ratios rose by 50-120 % and 45.4-336.1 %, respectively. National code proposed formulae were utilized to determine the theoretical load of tested beams and compared to matching experimental results. The predicted theoretical loads were found to be close to the experimental values.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.22 no.1
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• pp.18-30
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• 2017

The East Sea is almost entirely composed of sandy facies, and the facies type is the major factor influencing benthic polychaete communities. There have been few studies of the effects of environmental factors on benthic polychaetes in thermal discharge areas consisting of different sediment types. This study identified the spatial distribution patterns based on the species composition and distribution of benthic polychaete communities, and the environmental factors influencing benthic polychaetes near power plants were investigated. The polychaete communities in the Uljin, Hupo, and Gori coastal areas near the power plants in the East Sea were seasonally investigated from August 2006 to February 2013. As a result, 283 species were collected. The dominant species were Spiophanes bombyx, Magelona japonica, Lumbrineris longifolia, and Sternaspis scutata. Spiophanes bombyx was the dominant species at Uljin and Hupo, but M. japonica was the dominant species at Gori. Two dominant species from the coastal waters of the East Sea, Lumbrineris longifolia and M. japonica, were rare in the power plant water intake or drainage areas. Cluster analysis was performed to divide the study area into groups by the total organic carbon content, sediment grain size and facies patterns. This study suggests that the community structures of polychaetes are more affected by the total organic carbon, grain size of sediment and facies than by disturbance from thermal discharge, which only affected the polychaete community near power plant drainage areas.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.4
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• pp.378-385
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• 1998

• The Korean Journal of Quaternary Research
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• v.4 no.1
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• pp.15-26
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• 1990

Narrow (10-20 km wide) and steep (0.3-$2.4^{\circ}$) continental shelf off the eastern coast of Korea is covered with terrigenous clastic sediments reflecting the Holocene fluctuation of sea level. Surface sediments on the inner shelf consist of muddy sand and sandy mud with some gravels near the coast. However, sand or muddy sand, shell fragments and well rounded gravels occur near the edge of continental shelf at the depth of about 130-l50m. The coarse sediments near the shelf edge seem to be the relict or palimpsest sediments deposited under the nearshore environment during the low-stand or sea level due to so-called the Wisconsinan glaciation. Distribution of recent sediments near the coast and the inner shelf may reflect the affect of waves and currents precluding the deposition of fine sediment near the coast and on the shallow portion of shelf. Eastern Korean Warm Current also nay have played an important role to the transport and distribution of fine sediments from the south.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.4 s.142
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• pp.357-367
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• 2005

A numerical method is developed for the hydroelastic response of the Very Large Floating Structure considering the sea-bottom topography. The sea-bottom effects on the hydroelastic response of the floating structure is studied. The sea-bottom topography should be considered when the floating structure is constructed near the shore. To investigate the sea-bottom effects, four different sea-bottom topographies are considered in this study. finite-element method based on the variational formulation is used in the fluid domain, The pontoon-type floating structure is modeled as the Kirchhoff plate. The mode superposition method is adopted for the hydroelastic behavior of the floating structure.