• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.5
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• pp.364-371
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• 2015

This study is aimed to develop the dynamic analysis technique for a floating aquaculture in a shallow water region under the harsh sea condition. In case of the installation region to transform from a coastal area to the offshore area, the influence of sea bed with sea waves on the mooring lines was announced to be significant by other authors. In this study, the numerical tool was developed to solve dynamic behavior of the floating barge coupled with mooring lines in a shallow zone of the sea considering the influence of sea bed on the floating system.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.2
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• pp.84-88
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• 2012

A numerical skill for effective treatment of inclined boundaries in a finite element method is introduced. A finite element method has been frequently used to simulate hydraulic phenomena in a coastal zone since it can be applied to irregular and complex geometry. In case elliptic partial equations are governing equations for a finite element model, however, there is a difficulty in treating boundary conditions properly for cases in which boundaries are vertically inclined. In this study, a method to treat such inclined boundaries using Bessel functions for a finite element method is introduced and compared with analytical solutions.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.2
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• pp.67-76
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• 2017

In this study, the effect of caisson heel on the active earth pressure is investigated. Using limit analysis method, inclinations of slip surface developed above the heel with different lengths are analyzed. The shorter the heel length, the larger those of inside slip surface, however those of outside slip surface are not changed. According to the relative heel length, relationships of internal friction angle of backfill material - wall friction angle between caisson structure and backfill - friction angle acting on virtual section at the end of heel are presented. Earth pressures acting against caisson structure with relatively short heel are smaller than Rankine earth pressure but always greater than Coulomb earth pressure which does not consider the heel length.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.6
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• pp.422-432
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• 2013

A System Identification method to develop parametric models linking free surface elevation and wave pressure is presented and two models are built allowing for either wave pressure or free surface elevation simulation. Linear, time invariant model structures with static nonlinearities are assumed and solutions are sought in a form of autoregressive model with extra input (ARX). An arbitrary chosen free-surface elevation and wave pressure dataset is used for estimation of the models, which are subsequently verified against datasets with similar pressure gauge depth but different free-surface elevation spectra due to different meteorological conditions. It is shown that free-surface simulation using System Identification methods can perform better than traditional linear transfer function derived from linear wave theory (LTF), while wave pressure simulation quality using presented methods is generally similar to that obtained with corrected LTF.

• Journal of Ocean Engineering and Technology
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• v.11 no.3
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• pp.153-162
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• 1997

시간평균된 해안의 지하수위는 내륙쪽에 강우가 없는 경우에도 평균해수면 (Mean Sea Level)보다 1내지 2미터 정도 높은 것으로 관측되었다. 이러한 해안의 지하수위상승현상은 주로 파랑과 조석의 작용에 의해 나타난다. 본 연구에서는 지하수위상승에 미치는 조석 및 파랑의 효과를 현장관측결과를 통해 정량적으로 보여주었으며, 또한 이들 각각의 작용에 기인한 지하수위상승에 대한 해석해 및 최근 이론들을 제시하였다. 특히, 최근 지하수의 수리학적 모델링에 관한 연구에서 파랑의 침투 (wave runup infiltration)효과의 중요성이 강조되었는 바, 본 연구를 통해 종래에 보고된 바 없는 swash zone (shoreline과 runup limit사이)에서의 파랑의 침투속도(분포)를 지하수위관측자료를 이용해 간접적으로 산정함으로써 해안의 지하수위예측모델링을 보다 정확히 수행할 수 있으리라 사료된다.

• Journal of the Korean association of regional geographers
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• v.13 no.1
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• pp.32-42
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• 2007

In Sagye coast of Andeok-myeon, southwestern Jeju, shore platform of noncohesive Hamori Formation, marine terrace deposit of round gravels, coastal dune composed of shell sand and volcanic sand, and back lake are linked closely with each other. In this paper, the formation process of Sagye coastal geomorphic system analysed by using OSL dating method is as follows: Firstly, Hamori Formation is a horizontal stratum filed up of tuff reworked by submarine volcanic eruption during 3$\sim$7.6 ka BP. Hollow at the boundary between Hamori Formation' flat and Kwangheak Basalt's gentle slope become a back lake when block is appeared over the sea level by uplift. Secondly, while Hamori Formation was laid below sea level, gravels which had been broken and abraded at southwestern rocky coast composed of Kwangheak basalt or been transported through the small stream from adjacent hillslope were deposited in rapid flow environment. Thirdly, deposition of round gravels was ceased by earth uplift, and shore platform was constructed by abrasion process of energy of swash moving forward. As altitude of shore platform is equal to high tidal level of spring tide, compared it with present high tidal level of study area, earth is uplifted about 105m since shore platform was formed. Fourthly, much sandy sediments transported from offshore bottom covered shore platforms and marine terrace deposits. Lighter sediments among sandy sediments was blown to back, formed secondary sand dune since about 500 year.

• Environmental and Resource Economics Review
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• v.23 no.1
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• pp.21-42
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• 2014

In this study, we are estimating the economic effects of the rising sea level due to the climate change in the Korean Eastern and Southern coastal areas. Using disaggregated regional data, we also estimate the optimal rate of coastal protection. We use FUND (The Climate Framework for Uncertainty, Negotiation and Distribution) in order to obtain estimates of the expected inundation ratios by geographical district. Our estimates suggest that in Busan the ratio of inundated land to total territory will likely constitute 3.19% by 2100, while the number in Gangwon-do province is estimated to be lower at only 0.1%. We estimate the associated economic damage to differ by geographical district with the economically active regions such as e.g. Busan and Ulsan cities, or the Gyeongsang-nam-do province, likely to sustain relatively more damage. In Busan and Ulsan where the coastal line is relatively short and the size of expected economic damage is rather high, we estimate the optimal rate of coastal protection to be at the level of 98% and 92%, respectively. In the Kyeongsang-nam-do area that is also likely to suffer a substantial economic damage due to the inundation, we suggest the optimal ratio of coastal protection to be set at the level of 78%~79%. In contrast, in the Kangwon-do province where the expected economic damage is estimated to be low, the optimal rate of coastal protection is estimated to be around 43%, depending on the scenario.

• Economic and Environmental Geology
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• v.52 no.5
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• pp.409-425
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• 2019

Marine terraces, a step-like landform, are important geologic markers that provide tectonic information during the Quaternary Period. Marine terraces are well developed along all coastlines(East, West, and South) of the Korean Peninsula, those along the East coastline are the most distinctive. The marine terraces of the East coastline are classified into 4-6 flights that are several meters or several tens of meters above the present sea level. It is believed that these terraces, except for the lowest one, were formed in the middle Pleistocene. In the base of the OSL age dating results and Blake excursion events of magnetostratigraphy, the $2^{nd}$ and $3^{rd}$ terraces are correlated to the last interglacial stage. Considering the marine terraces linked to a sea-level curve of the Pleistocene, it is thought that regional tectonic movements have uplifted the East coastal area since the middle Pleistocene. Besides, former shorelines of each terrace have varied elevations from Gangreung to Busan bay, which can be divided into four regions, namely, Gangreung-Yonghanri(I), Homikot-Najung(II), Najung-Bangeojin(III), and Waesung-Busan Bay(IV). The former shorelines of each terrace at both Gangreung-Yonghanri(I) and Najung-Bangeojin(III) are higher than those in the other two regions, due to block movements by regional faults such as the Ocheon Fault or its subsidiaries, the Gampo Lineament and Ulsan Fault. Uplift rate of the East coast ranges from 0.2 m/ky to 0.3 m/ky, but each region shows different uplift rate.

• Journal of the Economic Geographical Society of Korea
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• v.25 no.4
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• pp.451-468
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• 2022

Leading enterprises in contract farming are in control of agricultural production and influence the structure of the agricultural system in contract areas. This study focuses on the contract farming of potatoes for manufacturing chips, which uses a high proportion of domestic raw materials, and identifies the characteristics of contract farming between confectionery company 𐩒 and potato farms in Haean-myeon, Yanggu-gun, Gangwon-do. This study also analyzes the impact of contract farming on local agriculture from the perspective of the industrialization of agriculture. The results of this study demonstrated that contracting companies ensured the quality of potatoes and smooth agricultural operations by first preferentially selecting farmhouses with land that is easy to work with and then supplying the necessary agricultural machinery to promote the intensification of their work. In addition, contracting companies influenced the centralization of the agriculture sector by selecting farmhouses capable of contracting over a certain scale and guaranteeing them sales channels and the specialization of potato farming in contract areas, mainly through the supply of processing varieties and the spread of cultivation technology. The results confirmed that these three dimensions of contract farming promoted the industrialization of local agriculture.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.6
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• pp.462-469
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• 2009

This study suggests a general formula of non-cohesive sediment transport rates for waves and currents which is also valid for wave only or current only condition. On-offshore sediment transport rates with the second order Stokes wave in the shallow water are calculated as the pickup rate times the distance. The formula depicts reasonably that high waves move material offshore, and low waves move material onshore. Also the formula, as is the case the waves with long period tend to move material onshore, shows good results.