• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.71-76
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• 2006

우리나라 대표적인 해운대 해수욕장은 백사장의 길이가 현재 약 1,400m, 폭은 $35{\sim}45m$, 평균수심은 약 1m에 달하는 대규모 해수욕장이다. 그리고 수심이 낮고 조차가 적으며, 수온이 따뜻하여 천혜의 조건을 갖춘 한국 최대의 해수욕장으로 한해 약 1200만 명이 넘는 관광객이 찾는 대표적인 명소이기도 하다. 그러나 지난 수십 년간의 해빈 유실로 인한 해수욕장의 존립자체의 위기가 현실화되고 있다. 해수욕장의 모래유실은 다년간에 걸쳐 진행되고 있으며, 여러 요인에 의하여 해안선의 위치와 폭이 달라지고 있다. 본 논문에서는 부산지역의 해운대 해수욕장을 선정하여 실험지역에 대한 측량을 RTK 방식으로 4개월간 3회에 걸쳐 실시하였다. 측량결과 1, 2, 3차에 걸쳐 총 3.36m의 해안선 증가의 효과가 나타남을 알 수 있었다. 또한, 모래포집시설을 설치하기 전, 후를 기점으로 비교한 결과를 파악하였으며, 향후 해빈 유실의 원인과 방지대책, 그리고 해안선 추출의 모니터링 시스템에 대하여 모색하고자 한다.

• Journal of Ocean Engineering and Technology
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• v.21 no.4
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• pp.15-20
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• 2007

The harbor siltation by longshore sediment transports has become a serious problem on the East Coast of Korea. A reasonable prediction of the longshore sediment rate is important to approach the siltation problem effectively. In the recently developed 1-line model, the empirical constants of the sediment transport formula, which include the absolute quantity of sediment transport rate and the spatial distribution of breaking wave height by wave deformation, are treated as calibration parameters. Since these constants should be determined by the very long-term shoreline data, the longshore sediment rates are much more reasonable values. The method was applied to Hupo Beach, which has experienced heavy siltation. The authors also discuss long-term shoreline change using aerial photos and the observed wave-induced current patterns. According to the result, the SW-direction sediment transport rate was $146,892m^3/year$, and the NE direction was $2,694,450m^3/year$ at Hupo Beach for the last 11 years. The siltation in Hupo Harbor might be affected by the NE-direction sediment transport from Hupo Beach.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1991.07a
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• pp.60-63
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• 1991

경제가 성장해 감에 따라 증가되는 수출입 물량의 원활한 소통을 위해 기존항만의 확장 및 신규항만의 개발이 요구되고 있으며, 또한 국민 생활수준이 향상됨에 따라 해안위락 시설의 확장 및 유지보존 역시 절실히 요구되고 있다. 연안개발사업은 부수적으로 주변해역의 환경을 변화시킨다. 예를들면, 사빈해안에 항구 또는 발전소건설을 위해 방파제 및 호안을 건설함으로써 해안지형 및 파랑과 흐름의 상태와 표사의 양상을 변화시켜 결과적으로 항구의 매몰 및 해안의 침식ㆍ최적 등의 심각한 문제를 야기시킨다.(중략)

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.4
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• pp.401-410
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• 2003

Three beaches of the Seogwang-ri coast in the western part of Wu Island, Jeju-do, are solely composed of rhodoliths (red algal nodules). The beach sediments are coarse sand to granule in size and they show the banded distribution according to size. Commonly the larger pebble-sized rhodoliths are concentrated near the rocky coast, resulting from the transportation of the nodules from shallow marine environments by intermittent typhoons. Based on the internal texture of the rhodoliths, it appears that crustose red algae, Lithophyllum sp., is the main contributor for the formation of the rhodolith. The coarse sand to granule-sized grains show that they started to grow from the nucleus as rhodoliths, but the surface was severely eroded by waves. However, the pebble to cobble-sized grains exhibit the complete growth pattern of rhodoliths and sometimes contain other calcareous skeletons. It is common that encrusting red algae are intergrown with encrusting bryozoan. The surface morphology of rhodolith tends to change from the concentric to domal shape towards the outer part. This suggests that the rhodolith grew to a certain stage by rolling, but it grew in more quiet condition without rolling as it became larger. Aragonite and calcite cements can be found in the pores within rhodoliths (conceptacle, intraskeletal pore in bryozoan, and boring), and this means that shallow marine cementation has occurred during their growth. Growth of numerous rhodoliths in shallow marine environment near the Seogwang-ri coast indicates that this area has suitable oceanographic conditions for their growth such as warm water temperature (about 19$^{\circ}C$ in average) and clear water condition due to the lack of terrestrial input of volcanoclastic sediments. Fast tidal current and high wave energy in the shallow water setting can provide suitable conditions enough for their rolling and growth. Typhoons passing this area every summer also influence on the growth of rhodoliths.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.5
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• pp.265-277
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• 2019

Using the measured data of waves and shore-line, we reviewed the grand circulation process and seasonal variation of beach cusp at the Mang-Bang beach from the perspective of trapped mode Edge waves known as the driving mechanism of beach cusp. In order to track the temporal and spatial variation trends of beach cusp, we quantify the beach cusp in terms of its wave length and amplitude detected by threshold crossing method. In doing so, we also utilize the spectral analysis method and its associated spectral mean sand wave number. From repeated period of convergence and ensuing splitting of sand waves detected from the yearly time series of spectral mean sand wave number of beach cusp, it is shown that the grand circulation process of beach cusp at Mang-Bang beach are occurring twice from 2017. 4. 26 to 2018. 4. 20. For the case of beach area, it increased by $14,142m^2$ during this period, and the shore-line advanced by 18 m at the northen and southern parts of the Mang-Bang beach whereas the shore-line advanced by 2.4 m at the central parts of Mang-Bang beach. It is also worthy of note that the beach area rapidly increased by $30,345m^2$ from 2017.11.26. to 2017.12.22. which can be attributed to the nature of coming waves. During this period, mild swells of long period were prevailing, and their angle of attack were next to zero. These characteristics of waves imply that the main transport mode of sediment would be the cross-shore. Considering the facts that self-healing capacity of natural beaches is realized via the cross-shore sediment once temporarily eroded. it can be easily deduced that the sediment carried by the boundary layer streaming toward the shore under mild swells which normally incident toward the Mang-Bang beach makes the beach area rapidly increase from 2017.11.26. to 2017.12.22.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.2
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• pp.96-102
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• 2014

A three-dimensional beach evolution model was presented to predict morphodynamics around a river mouth. The presented model was based on the depth-averaged (2DH) and quasi three-dimensional (Q-3D) nearshore current modules, and the model took into account shoreline changes, the effect of advection diffusion of suspended load and discharged sediments from the river. First, the 3D beach evolution model was applied to the formation of sand spits and terrace at the river mouth in order to investigate the performance of the model. Secondly, the model was applied to the river mouth at the Ara River, facing the Sea of Japan. The formation of sand spit at the Ara River in winter season was reproduced. The computed result showed qualitatively agreement with field site observation.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.4
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• pp.296-304
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• 2010

The shoreline change caused by the construction of shore protection structures are discussed based on the example of Youngrang coast, Sokcho where the coastal erosion control system(CECS), three artificial headlands and two submerged breakwaters are being constructed. The study qualitatively analyzed the shoreline changes of Youngrang coast using available satellite/aerial photographs and camera photographs taken during the construction period of 6 years since 2002 for the artificial headlands construction. The main results from the study are as following. (1) Before the installation of the middle artificial headland, longshore drifts along Youngrang coast are transported in the NW-SE direction according to the seasonally different wave characteristics. (2) During the CECS construction the shoreline is continuously changed by altering the local longshore drift budget. Especially, the middle artificial headland induces considerable change of shoreline by blocking the sediment supply from the southern pocket beach to the northern pocket beach and by accelerating the sediment accretion at the wave shadow zone behind its head. It induces the asymmetry on the net longshore drift causing the significant erosion at the center of the southern pocket beach. (3) The study demonstrates that serious unintended erosion/accretion problem are possibly occurred due to local changes on the wave transformation and the sediment transport by the construction of coastal erosion control system.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.2
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• pp.107-118
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• 2010

The purpose of this study was to set the boundary of the coastal sand dunes and to analyze the change characteristics of land cover types using aerial photographs on Osan and Dongho coastal sand dunes in Yangyang. The boundaries of sand dunes were established using digital soil map, and land cover maps were made for each year using aerial photographs. As results of analysis, both beach and farmland areas have been decreased, since 1974 and forest area was relatively increased due to planting and forest growth. Facilities and bare land have been greatly increased since 1992. Loss of wetland, and beach due to these changes had an impact on the ecosystem destruction of sand dunes.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.6
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• pp.766-772
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• 2016

The composition of the diet of juvenile barbel steeds, Hemibarbus labeo was studied using 67 specimens collected in August, 2004 from the surf zone of the Nakdong river estuary. The fish examined ranged from 5.1 to 9.7 cm in standard length (SL). Hemibarbus labeo was found to be carnivorous and consumed mainly amphipods, with teleosts, polychaetes, and shrimps following. They showed size-related changes in diet. Small individuals (< 6.4 cm SL) mainly consumed amphipods. As fish size increased, the portion of amphipods consumed decreased, while a reverse trend was evident for teleosts. It was also observed that Hemibarbus labeo consumed more amphipods and polychaetes during the day, while fish served as their main prey during the night.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1B
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• pp.115-123
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• 2008

In the present study, a three dimensional hydrodynamic characteristics around the fully submerged dual breakwaters with a sand beach has been investigated numerically using a 3-D numerical scheme, which can determine the eddy viscosity with LES turbulence model and is able to consider wave-structure-seabed interaction in 3-dimensional wave field (LES-WASS-3D), recently developed by Hur and Lee (2007). Based on the numerical experiments, strong vortices can be generated fore and aft edges of the structures, and propagate lee sides. Thus relatively large circulation flows are occurred around submerged breakwaters. The 3-D flow hydrodynamic characteristics have been examined by mean flows and mean vortices for various x-y, x-z sections and y-z layers. Wave height distribution and wave set-up around and over submerged breakwaters, and breaking point migration toward shore side is discussed in detail.