• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.67-70
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• 2005

As the demand of sea leisure increases recently, interest is converged sea safety and offer of quick and systematic information according to weather environment that change rapidly. Use of Electronic Navigational Chart(ENC) in the sea in offer of geography information through Mobile terminal was gone to level that run in PDA environment in domestic by bulky good physician data information and complicated processing way of island in the sea expression in sea, and is loaded in obligatory sailing equipment of ship yet and is used. In this paper, we develop server system that take charge index for offer of quick information through Restrictive resource management and Caching Technique, image conversion and database construction and fast search to service various marine leisure informations of Weather Data and so on and image information of ENC in the sea to Mobile portable phone terminal efficiently.

• Ocean and Polar Research
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• v.27 no.4
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• pp.497-507
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• 2005

This paper presents a method for obtaining mosaic aerial photographs that are useful for a long-term shoreline change study in the Nakdong estuary. Although this method involves digital photogrammetry software of the shelf its usage can be simplified to accomodate the shoreline change study. Ground control points, which are common in aerial photographs, were measured from digital maps. Block triangulation was highly affected by land-based GCPs. Extension of tie points near the shoreline to vertical control points gave more reliable results for the block triangulation. A constant Digital Elevation Model (DEM), close to mean sea level, was employed to produce ortho-rectified photographs, from which mosaic photographs were made. Accuracy of photographs were found to be acceptable for the analysis of long-term shoreline change, and the promising construction of a shoreline change database in the Nakdong estuary.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.3
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• pp.119-126
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• 2018

In this study, In this study, the Datum Level-based hydrography surveying system and the ellipsoid-based system were analyzed to acquire more consistent depth data. For the study, the ellipsoid-based surveying for hydrography was conducted twice for the same track line. And the depth was calculated by correcting rise and fall of water level (water level change by tidal energy and other marine environmental energies) respectively by the traditional water level correction method and ellipsoidally referenced water level correction method. there is able to check that Ellipsoid-based hydrographic surveying data is more improved than Datum Level-based hydrographic surveying data in aspect of level difference phenomenon in the same area (surveying line). This result shows that if the Ellipsoid-based hydrographic surveying is performed, the sea level change (tidal energy and other marine environmental energy) of the survey area in real time could be reflected to more consistent generating bathymetric data.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1B
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• pp.71-85
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• 2011

Saltwater intrusion effects of coastal aquifers in Korea peninsula were analyzed through trend analysis with groundwater level, seawater level, seawater temperature, and electrical resistivity(EC) data sets. Groundwater level and EC data sets from 27 coastal regions were collected and analyzed. Groundwater level was stable for all the regions however EC data showed stable or changing trends (9 increasing, 10 stable, and 8 decreasing regions). Seawater temperature was collected and analyzed for 14 regions and they are increasing for most regions (12 increasing and 2 stable regions). Seawater level was also collected and analyzed for 24 regions and is rising for most regions (18 rising, 3 stable, and 3 falling regions). Especially, west cost regions have stronger increasing tendencies of seawater level, seawater temperature, and EC than eastern and southern coastal regions. Therefore the saltwater intrusion problem can be serious for west cost regions in Korea peninsula and it is necessary to establish a plan to minimize the damages from saltwater intrusion.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.14 no.3
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• pp.232-239
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• 2002

This paper studies the behavior of mooring line of silt protector according to the change of sea level. It is found from the analysis of the behavior that if the taut cable length has been determined appropriately within the range of safety factor, the tensioned cable has almost constant tension regardless of the water depth. The whole structure, however, becomes unstable due to the loss (zero tension) of the released cable tension. It is also recognized from the investigation for the effect of intial straight line angle on the behavior of mooring line that the design through the conceptually combined consideration of the cable tension, total scope and buoy deflection has to be required in the mooring analysis. Finally, the material of cable is not damaged because the cable tension is reduced by attached shellfish, but the whole structure may be also unstable by the effect on the anchor angle, total scope and buoy deflection.

• Journal of the Korean earth science society
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• v.24 no.1
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• pp.46-60
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• 2003

In Namyang Bay of western Korea, macrotidal-flat deposits are divisible into three late Quaternary units: Unit M1 of upper marine mud, Unit T1 of middle siderite-bearing terrestrial clay, and Unit M2 of lower marine mud. Unit M1 represents typical Holocene intertidal mudflat deposits, showing a coarsening-upward textural trend. It probably resulted from the continual retrogradation of tidal flat during the mid-to-late Holocene sea-level rise. Reddish brown-color Unit T1 consists of homogeneous clay with abundant freshwater siderite grains and plant remains. Unit T1 is clearly separated from the overlying Unit M1 by a sharp lithologic boundary. Radiocarbon age, siderite grains and lithologic features indicate that Unit T1 is originated from freshwater bog or swamp deposition infilling the localized topographic lows during the early Holocene age. Overlain unconformably by early Holocene swamp clay, Unit M2 is orange to yellow in color and mottled, suggesting significant degree of weathering during the sea-level lowstand. Such subaerial oxidation is confirmed in the vertical profiles of geotechnical properties, clay mineral assemblages and magnetic susceptibility. Unit M2 appears to be correlated with the upper part of the late Pleistocene tidal deposits developed along the western Korean coast. The sedimentary succession of the Namyang-Bay tidal-flat deposit provides stratigraphic information for the Holocene-late Pleistocene unconformity and also permits an assessment of the preservation potential of the late Pleistocene marginal marine deposit along the western coast of Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.2
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• pp.116-121
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• 2004

Physiological responses and tolerance limit of hybrid striped bass $(Morone\;Chrysops\;male{\times}\;M.\;saxatilis\;female),$ were investigated on salinity changes from 33 psu to 0 psu and from 0 to psu 33 psu in two separate trials, respectively. In the acute salinity decrease from sea water (33 psu) to fresh water (0 psu), plasma level of cortisol, glucose, total protein, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were not affected, however, $Na^+,\;Cl^-$ and osmolality significantly decreased. In the acute salinity increase from fresh water to sea water (33 psu), plasma cortisol level did not change. Glucose and total protein concentrations in plasma and hematocrit (Hct) decreased, whereas AST, ALT, $Na^+,\;Cl^-$ and osmolality increased. The hybrid striped bass can overcome the acute changes of salinity, from 0 psu to 33 psu or from 33 psu to 0 psu, But salinity decrease stressed the fish much more than salinity increase.

• Journal of Environmental Impact Assessment
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• v.26 no.3
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• pp.171-180
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• 2017

The vulnerability analysis of climate change driven disaster has been used as institutional framework for the urban policies of disaster prevention since 2012. However, some problems have occurred due to the structure of vulnerability analysis, such as overweighted variables and duplicated application of variables of similar meaning. The goal of this study is to examine the differences of results between the method of current guideline and the method of weight equalization. For this, we examines the current structural framework of the vulnerability analysis, and performs empirical analysis. As a result, the extent and magnitude of vulnerability showed different spatial patterns depending on the weighting methods. Standardized weighting method relatively represented wider vulnerable areas compared to the pre-existing method which follows the current instruction manual. To apply the results of vulnerability analysis to urban planning process for disaster prevention, this study suggests that the reliability of the results should be ensured by improving analytical framework and detailed review of the results.

• Journal of the Korean earth science society
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• v.29 no.6
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• pp.454-465
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• 2008

Benthic foraminiferal assemblage and AMS radiocarbon dating of core sediments from the northern shelf of the East China Sea were analyzed in order to understand the paleoenvironment and sedimentary environmental changes around the Korean marginal seas since the last glacial maximum (LGM). The core sediments, containing continuous records of the last 16,000 years, reveal a series of well-defined vertical changes in number of species (S), P/T ratio and species diversity (H) as well as foraminiferal assemblage. Such down-core variations display a sharp change at a core depth of approximately 240 cm, which corresponds to ca. 10,000 year B.P. The sediments of the lower part of the core (240${\sim}$560 cm, Zone I), including the well-developed tide-influenced sedimentary structures, are characterized by high abundances of Ammonia beccarii and Elphidium clavatum (s.l.) and low values in number of species, P/T ratio and diversity. These tide-influenced signatures and foraminiferal assemblage characters suggest that the sediments of Zone I were deposited in a coastal environment (water depths of 20${\sim}$30 m) such as tidal estuary with an influence of the paleo-rivers (e.g., old-Huanghe and Yangtze rivers) during the early phase of the sea-level rise (ca. 16,000 to 10,000 years) since the LGM. In contrast, the upper core sediments (0${\sim}$240 cm, Zone II) are characterized by abundant Eilohedra nipponica and Bolivina robusta with a minor contribution of A. ketienziensis angulata and B. marginata. and high values in number of species, P/T ratio and diversity. Based on relative abundance of these assemblage, Zone II can be divided into two subzones (IIa and IIb). Zone IIa is interpreted to be deposited under the inner-to-middle shelf environment during the marine transgression in the early Holocene (after ca. 9,000 yr B.P.) when sea level rapidly increased. The sediments of zone IIb most likely deposited after 6,000 yr B.P. under the outer shelf environment (80${\sim}$100 m water depth), which is similar to modem depositional environments. The muddy sediments of zone IIb were probably transported from the old-Huanghe and Yangtze Rivers during the late Holocene. We suggest that the present-day oceanographic conditions over the Yellow and the East China Seas have been established after ca. 7,000${\sim}$6,000 yr B.P. when the Kuroshio Current began to influence this area.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.3
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• pp.197-208
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• 2016

The WCPFC CMMs related to tropical tunas have been strongly restricting fishing capacity and operating activities of main fisheries, especially purse seine fishery. In terms of changes in fishing trend by implementing relevant measures of FAD set, the number of FAD set by Korean purse seine fleet showed a decreasing pattern with the lowest level of FAD set proportion among major distant water fishing nations. With regards to the FAD closure, there was no significant change in fishing effort but a drop in catch, especially bigeye tuna during the period of FAD closure. Moreover, it showed closely similar trends between the number of FAD set and bigeye tuna catch. In terms of measures related to the high sea area including a ban on fishing on the HSP and limitation of fishing days on the high sea by flag state, proportions of catch and effort on the high sea had sharply declined after implementing those measures. As relevant measures are expected to be strengthened, it should pay attention to change of coastal nations policies and focus on improving fishing efficiency of unassociated school set with multi-pronged efforts.