• Journal of the Korean Geographical Society
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• v.50 no.2
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• pp.147-164
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• 2015

This study analyzed characteristics and tendencies of seasonal change on shoreline and beach with 8 beaches at East Sea coast by topographical survey for 2 years from March 2012 to February 2013. The shorelines of East Sea coast appeared that amount of seasonal change was bigger than amount of annual change. The seasonal change tendencies between Gangwon-do and Gyeongsangbuk-do coast areas existed some regional differences. To synthesize seasonal changes on 8 beaches of East Sea coast, shoreline advance and beach deposit showed clearly in summer and shoreline retreat and beach erosion showed clearly in autumn. This result is different from tendencies of seasonal change in many mid-latitude coast areas of the world, but generally corresponds with reference studies in west coast and east coast. The major factor of beach erosion showing mostly in summer is storm wave caused by typhoon. The beach erosion by storm wave also occurred in late winter. And it assumes that the beach deposit showing mostly in autumn is result of equilibrium processes of coast area against strong erosion in summer.

• Korean Journal of Remote Sensing
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• v.37 no.4
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• pp.803-813
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• 2021

Coastal erosion has been a threat to coastal communities and emerged as an urgent problem. Among the coastal communities that are under perceived threat, Cotonou located in Benin, West Africa, is considered as one of the most dangerous area due to its high vulnerability. To address this problem, in 2013, the Benin authorities established seven groynes at east of Cotonou port, and two additional intermediate groynes have recently been integrated in April 2018. However, there is no quantitative analysis of groynes so far, so it is hard to know how effective they have been. To analyze effectiveness, we used optical satellite images from different time periods, especially 2004 and 2020, and then compared changes in length, width and area of shoreline in Cotonou. The study area is divided into two sectors based on the location of Cotonou port. The difference of two areas is that Sector 2 has groynes installed while Sector 1 hasn't. As result of this study, shoreline in Sector 1 showed accretion by recovering 1.20 km² of area. In contrast, 3.67 km² of Sector 2 disappeared due to coastal erosion, although it has groynes. This may imply that groynes helped to lessen the rate of average erosion, however, still could not perfectly stop the coastal erosion in the area. Therefore, for the next step, we assume it is recommended to study how to maximize effectiveness of groynes.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.8 no.2
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• pp.9-16
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• 1990

This is a geodetic study on the the shoreline changes occurred by the facilities constructed in the beach. There are emperical, hydrological and numerical methods in predicting of the shorline changes. Numerical method is the most suitable method in the field of geodesy. There are many predicting models. This study adopted one-line model because it has a few hydrological factor and simplify the natural phenomena. This study established the ideal seawall boundary condition, applied the explicit model and the implicit model in the Dongsan harbour in East Sea, and could predict the optimum seawall position for protection of shore. The results are following ; Seawall protect shore of which input angle of wave is below 20$^\circ$, a ratio of wave height bleak/line does not effect in shoreline changes. The implicit model is accuracy but can not predict longtime change. But the explicit model is the opposite of the implicit model.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.16 no.4
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• pp.258-267
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• 2004

Coastal and harbor structures, which are constructed for the beach protection and coastal zone development, often cause the severe beach erosion problem resulted from changes of longshore sediment transport. In this study, we present a new methodology to estimate the longshore sediment transport rates using the measured data of beach profiles or shorelines. The methods is applied for the prediction of longshore sediment transport rates along Kailua beach, Hawaii and shorelines in the vicinity of Anmok Harbor, Korea.

• Journal of the Korean earth science society
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• v.26 no.6
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• pp.584-596
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• 2005

Morphology, surface sediments, sedimentation rates and sea-cliff erosion have been monitored, for one year to investigate the shoreline changes and tidal beach characteristics in Cheonsu Bay along the west coast of Korea. The seacliff of the bay consists of intensively weathered sedimentary rocks and soft soil, showing an erosion range of $-58.9\~73.3cm/yr$ by a weak wave forcing. Active sea-cliff erosions are recognized by peculiar geomorphic features, including saw teeth-shaped coastline, gravels, relict weathered basement-rock and 'Island Stack' exposed on the high-tide beach surface. The beach sediments show low compositional maturity at the south and north headlands and gradually high towards the central part. This observation seems to be caused by the fact that beach sediments are to originate from the both headlands in the study area and then transported by long-shore current associated with a wave action.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.2 no.2
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• pp.67-74
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• 1990

A numerical model is developed to predict the shoreline change by the coastal structures constructed. In order to describe the wave deformation at the shadow zone of the structure, the present model employs the mild-slope equation in steady state and the wave ray method using the coefficients of wave refraction, diffraction and shoaling. In the model results of shoreline changes for the various structures. it showed a qualitative agreement with the findings observed in the field such as tombolo, and the response of this model was found to be very sensitive to the longshore distribution of wave heights. It was also applied to a field area. From the results of the application this model is proved to be useful around the complex coastal structures and bottom topography.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.451-456
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• 2006

Shoreline changes its shape and attribution dynamically by natural, unnatural acts and is the most important information for defining a countries territory. These shorelines can apply to frame work of MGIS, and they are getting important because we can implement the data for creating monitoring systems around coastal areas. This study proposed an algorithm for extracting shorelines automatically using a new developed Lidar data which is applied in ocean and coastal areas. Its result was compared to shorelines which were derived from ground survey. It showed stable shorelines in both natural, and artificial coast areas. It showed the possibility of extracting shorelines with LiDAR data and proved the method was more efficient and economical compared to recent studies and methods.

• Ocean Systems Engineering
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• v.8 no.1
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• pp.1-20
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• 2018

The target area of the proposed study, Mamaia beach, is a narrow stretch of sand barrier island that sits between the Siutghiol Lake and the Black Sea. In the northern part of the bay, is located the Midia Port, where between 1966 and 1971 a long extension of 5 km of the offshore was built. Because of this extension, the natural flow of sediments has been significantly changed. Thus, the southern part of the Mamaia Bay had less sand nourishment which meant that the coast was eroding and to prevent it a protection of six dikes was built. After approximately forty years of coastal erosion, the south of the Mamaia Bay had in 2016 a new protection scheme, which includes first of all the beach nourishment and a new dike structure (groins scheme for protection) to protect it. From this perspective, the objective of the proposed study is to evaluate the effectiveness of the old Master plan against the new one by modeling the outcome of the two scenarios and to perform a comparison with a third one, in which the protection dikes do not exist and only the artificial nourishment has been done. In order to assess the wave processes and the current patterns along the shoreline, a complex computational framework has been applied in the target area. This joins the SWAN spectral phase averaged model with the 1D surf model. Furthermore, new UAV technology was also used to map out, chart and validate the numerical model outputs within the target zone for a better evaluation of the trends expected in the shoreline dynamics.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.4
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• pp.223-229
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• 2020

The fault failure process with time difference affects the initial generation of waveforms of tsunamis, which consequently changes the runup height on the coast. To examine the effect of time difference in fault failure process on the runup height, a numerical simulation was conducted assuming a number of virtual subsea earthquakes in the west coast of Japan. Results revealed that maximum runup heights along the east coast of Korea were minimal when the subfaults were aligned parallel with the shoreline. Meanwhile, if they were located perpendicular to the shoreline, the superposition effect of the initial surface by each subfault was noticeable, resulting in an increase in maximum runup height on the coast.

• Journal of Environmental Science International
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• v.19 no.5
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• pp.617-625
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• 2010

Rapid industrialization has brought Nam-Hae area serious environmental problems associated with released oil and other hydrocarbons. In this work, in order to enhance the quality of the shoreline sediment we made enviro-chemical analyses of its substances, TPHs and microbial growth after treating with oxygen releasing compound(ORC) such as $MgO_2$. Total organic compound(TOC) was reduced from 33.45% to 25.1~31.08% meanwhile COD decreased from 27.5~28.9mg/$g{\cdot}dry$ to 19.9~26.1mg/$g{\cdot}dry$ for input of 2~10% $MgO_2$ in 20days. For 10% $MgO_2$ input, TP and TN were reduced by 13.3% and 18.8%, respectively. Most of all TPH was decomposed by max. 42.4% in 21days, and the total viable count of microbes was found to be exponentially increased by 75.9%.