• Current Research on Agriculture and Life Sciences
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• v.13
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• pp.45-53
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• 1995

This research was conducted to investigate morphological and genetic variation of Allium victorialis val. platyphyllum which growed wild in Mt. Hambaek, Mt. Odae, and Ullungdo. The tree layer of Allium victorialis var. platyphyllum community in Mt. Hambaek and Mt. Odae was dominated by Quercus mongolica. The tree layer of Ullungdo generally consist of Fagus crenata var. multinervis, Acer triflorum, Sorbus commixta, and Tilia insularis. In the herb layer, Rumohra standishii, Trillium tschonoskii, and Lilium hansonii are common at Allium victorialis var. platyphyllum community in Ullungdo. The vegetation in Ullungdo was widely different from those in Mt. Hambaek and Mt. Odae by species composition. The result of Principal Component Analysis(PCA) and Canonical Discriminent Analysis of by the 8 characters showed that Allium victorialis var. platyphyllum could be classified into 2 groups: (one ; Mt. Hambaek and Mt. Odae, the other ; Ullungdo). In PCA, the major factors in the first principal component group was angle of leaf apex. Variation of band by isozyme GOT(glautamate oxaloaccetate transaminase) is similar between Mt. Hambaek and Mt. Odae. However, Ullungdo differed from Mt. Hambaek and Mt. Odae in variation of bands.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.73-73
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• 2019

지구 표면의 약 2%에 해당하는 담수에서 육상계 전체가 흡수하는 탄소의 50%가 배출되며, 이는 토양표면에서 배출되는 탄소량에 비해 더 큰 수치로 전 지구적 탄소순환 해석에 중요한 역할을 한다. 특히, 내륙수역과 대기의 경계면에서 $CO_2$ 이동은 전 지구적 탄소순환의 중요한 구성요소로 평가되고 있다. 호수와 저수지 같은 담수 저류시설은 육상에서 기인한 탄소의 운송 및 처리 역할을 한다. 하지만, 저수지에서 온실가스배출량을 평가할 수 있는 명확한 방법론이 부족하며, 전지구 규모 GHGs배출량에 대한 추정에 대한 불확실성이 상당히 큰 상황이다. 본 연구에서는 몬순기후대에 위치한 인공저수지를 대상으로 보다 신뢰도있는 온실가스 배출량 추정을 위해 $CO_2$ NAF 산정하고, 산정에 영향을 미치는 인자들을 분석 하였다. 분석을 위해 $CO_2$ NAF 산정에 필요한 수리 및 수질 인자들을 2017년부터 2018년까지 수집하고, 기초통계량 및 상관분석을 실시하였다. 또한, 주성분분석(PCA) 및 다중선형회귀모델(MLR)과 랜덤포레스트(RF) 기법을 사용해 변수 중요도를 평가하였으며, $CO_2$ NAF 산정 주요인자인 기체교환 계수를 경험적 모델 3종(Cole and Caraco, Crusius, Vachon), 표면갱신형 모델 4종(Heiskanen, Maclntyre, Read, Soloviev)을 비교, 검토하였다. 조사기간 동안 기체교환계수 산정 결과 Crusius 모델 예측값이 평균 $0.342(0.047{\sim}4.323)cm\;hr^{-1}$으로 검토한 모델중 가장 낮은 평균값을 보였으며, Heiskane 모델이 $2.135(0.337{\sim}5.152)cm\;hr^{-1}$으로 가장 큰 평균값을 보였다. 대상 수체는 연주기로 완전혼합되며 수온성층이 약화되는 시기에 저수지 표층 아래에 축적된 탄소가 표층으로 전달되어 높은 수준의 p$CO_2$를 보이며, 수표면에 큰 난류 강도가 작용하는 기간에 대기중으로 배출(pulse emission) 기작이 나타난다. NAF 산정결과 경험적 모델의 NAF값($-1246.0{\sim}6510.3mg-CO_2m^{-2}day^{-1}$)은 표면갱신형 모델 NAF값($-1436.1{\sim}8485.7mg-CO_2m^{-2}day^{-1}$)보다 낮은 수준을 보였으며, 풍속의 함수만을 이용하는 경험적 모델보다 부력 플럭스와 난류 혼합의 영향을 고려하는 Macintyre, Heiskanen모델이 성층 저수지의 $CO_2$ NAF 산정에 적합한 것으로 나타났다. $CO_2$ NAF 산정의 주요인자로 MLR모델은 Tw, EC, pH, Chla, TOC, Alk, RF모델은 EC, DO, TOC가 중요 변수로 평가되었다. PCA 분석결과, 수온이 낮고 성층이 약화되며 pH가 낮은 상태에서 NAF가 큰 것으로 나타났다.

• Ecology and Resilient Infrastructure
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• v.8 no.4
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• pp.165-178
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• 2021

We studied driftwood behaviors including generation and deposition in a tsunami using a numerical simulation. We used an integrated two-dimensional numerical model, which included a driftwood dynamics model. The study area was Sendai, Japan. Observation data collected by Inagaki et al. (2012) were used to verify the simulation results by comparing them with driftwood deposition patterns. A simplified model was developed to consider the threshold of driftwood generation by the drag force of water flows. To consider the volume of driftwood generated, we estimated the total wood number in the study area using Google Earth. Therefore, we simulated more than 13,000 pieces of driftwood that were generated and transported inland from approximately 300,000 trees that were growing in the forest. The final distribution of the driftwood was similar to the observation data. The reproducibility of the generation and deposition patterns of driftwood showed good agreement in terms of longitudinal deposition pattern. In the future, a sensitivity analysis on driftwood parameters, such as the size of the wood, boundary conditions, and grid size, will be implemented to predict the travel patterns of driftwood. Such modeling will be a useful methodology for disaster prediction based on water flow and driftwood.

• Journal of the Korean earth science society
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• v.40 no.2
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• pp.149-162
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• 2019

In the macro-tide open coast of the Korean western coast, typhoon effects were investigated in terms of variations on topography, surface sediment, and sedimentary environment, which appeared before and after the typhoon Kompasu of 2010. The Kompasu of small size and strong intensity landed on the southwestern coast of the Korean Peninsula and passed across the inland between September 1st and 2nd in 2010. Topography and surface sediments before and after the typhoon were measured and sampled along the survey line of 22 sites in the Gochang Donghori intertidal flat. The intertidal area was divided into high tidal zone, middle tidal zone, and lower tidal zone on the basis of mean high water level, mean sea level, and mean low water level. Topographic variation before and after the typhoon represented deposition of average 0.03 m in high tidal zone, erosion of average -0.15 m in middle tidal zone, and erosion of average -0.39 m in lower tidal zone, respectively. Surface sediments of the intertidal flat consisted mainly of fine to medium sands, and the ratio of fine sand was the largest both before and after the typhoon. Surface sediments after the typhoon became finer in mean grain size showing well sorting rather than those before the typhoon.

• Journal of the Society of Disaster Information
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• v.15 no.2
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• pp.175-185
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• 2019

Purpose: The purpose of this study is to propose a direction planning integrated waterfront cultural city in terms of urban economic revitalization through regeneration of former industrial harborfront and the creation of cultural living spaces based on regional history in order to pursue urban activities. Method: Analyzing planning waterfront and historical cultural space based on MM21's development policy and strategy under the growth process and development of Yokohama. Results: MM21 is the core public project out of the six major projects promoted by Yokohama, which is on the brink of satellite cities for the expansion of Tokyo with a goal of qualitative transformation of former harbor. It is planned to be developed as a creative cultural waterfront city for an integrated urban development. Conclusion: Planning waterfront cultural city, which takes advantage of the former harbor city derived through MM21 analysis, provides the cityscape towards the sea and the port via the viewing point and opens the waterfront open to the port and the sea Space and Esplanade landscape development, preservation of historic buildings and cultural assets, recycling as cultural art space, waterfront space planning that cooperates with public culture art and pedestrian network.

• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.491-500
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• 2018

Due to changes in the distribution industry, inner harbors have been on a sharp decline in the recent past. However, through the application of the right development plans, such harbors can be revitalized into vibrant urban areas again. The importance of inner harbors has been recognized by the relevant authorities in Korea which are now pushing forward with redevelopment plans for its inner harbors. This study proposes a new approach to redevelopment plans based on the recognition that inner harbors have unique characteristics involving both inland areas and the ocean. In the study, representative inner harbors were selected and analyzed comparatively according to two distinct concepts of location: the Gateway Concept and the Central Place Concept. Based on these concepts, the conditions of the inner harbors were examined. Their location can be typed, and development directions were proposed according to their types and conditions. However, difficult points such as isolation and separation between an urban district and the harbor area, can be obstructions to their potential revival. An inner harbor needs to be considered as an intermediary, connecting place between the ocean and the city, not as another ordinary development area. In addition, a redevelopment plan should be accompanied by a strategic viewpoint to make the most of this feature.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.550-556
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• 2020

Over the past years, the role of ports in the global network of supply chains has becoming increasingly important, not merely as a physical location for loading and unloading goods, but also as an essential center of economic activity where additional value is added to cargo. Due to the overall growing importance of ports, each country has chosen to adopt hub growth as a primary economic strategy. Northeast Asia in particular, due to its high population density, experiences intense competition between its ports. Busan's port, as a result, has used the establishment of Distripark in order to attract high and stable trade volume, and compete more effectively with other ports in the region. This study estimates the unit cost of the logistic process for the all principal cargos handled at Busan New Port, with the findings revealing that unit cost increases gradually starting with chemical products, LME bulk goods, automobile parts, LME containers, general cargoes, and LME inland transportation goods coming in last. Future research will look more closely at all all categories of cargo handled in the Distrpark of Busan New Port, thereby enabling us to better understand the value created by the port, and how to best implement effective trade volume-attraction strategy.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.2
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• pp.52-63
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• 2021

In previous research, the coastal wetlands were detected by using the vegetation indices or land cover classification maps derived from the multispectral bands of the satellite or aerial imagery, and this approach caused the various limitations for detecting the coastal wetlands with high accuracy due to the difficulty of acquiring both land cover and topographic information by using the single remote sensing data. This research suggested the efficient methodology for detecting the coastal wetlands using the sentinel-2 satellite image and SRTM(Shuttle Radar Topography Mission) DEM (Digital Elevation Model) acquired in Gomsoman Bay, west coasts of South Korea through the following steps. First, the NDWI(Normalized Difference Water Index) image was generated using the green and near-infrared bands of the given Sentinel-2 satellite image. Then, the binary image that separating lands and waters was generated from the NDWI image based on the pixel intensity value 0.2 as the threshold and the other binary image that separating the upper sea level areas and the under sea level areas was generated from the SRTM DEM based on the pixel intensity value 0 as the threshold. Finally, the coastal wetland map was generated by overlaying analysis of these binary images. The generated coastal wetland map had the 94% overall accuracy. In addition, the other types of wetlands such as inland wetlands or mountain wetlands were not detected in the generated coastal wetland map, which means that the generated coastal wetland map can be used for the coastal wetland management tasks.

• Journal of The Geomorphological Association of Korea
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• v.19 no.3
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• pp.143-151
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• 2012

The tsunami disasters and tectonic movements derived from mega-earthquake(M 9.0) which occured in the sea floor of the Pacific side of northeast Japan in March, 2011 were investigated. Landward invasion limit of the tsunami was 4.0km from the present coastline in Sendai coastal plain. It was observed that sandy deposit was dristributed largely in coastward part and muddy deposit was distributed largely in landward part. The ratios of distribution distances of the above two deposits were, respectively, 60~75% and 25~40% of the whole invasion distance of the 2011 tsunami. The ratios of the above distribution distances of tsunami deposits could be used to estimate landward invasion distances of the past maga-tsunamies(e.g. '2,000year B.P. Mega-Tsunami' and 'Jogan Tsunami' etc.) in Sendai coastal plain. The mega-scale tsunami disasters were caused by the low and flat geomorphic condition in the Sendai coastal plain and the increasing effect of tsunami height affected by narrow inlet condition of the so-called Ria's coast in the Sanriku coastal area respectively. Tectonic subsidences caused by the mega-earthquake in march, 2011 were observed in many areas of Ishinomaki, Ogawa, Ogachi and Onagawa coasts in northeast Japan. The displacements of tectonic subsidence were between 0.5 meters and 1.0 meters.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.289-296
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• 2021

This study aimed to analyze the optimal transplanting date of the floury endosperm rice varieties Hangaru, Seolgeang, Singil, and Baromi2 allowing to reduce the viviparity rate. The viviparity rate rapidly increased with the mean temperature during the ripening stage. Therefore, to reduce the viviparity rate, we calculated the optimum heading date based on the safe heading date limit in each area so that the ripening stage occurred at lower temperatures. hen, the effects of changes in heading date were monitored by recording the transplanting date and the temperature during the growth period. The transplanting date was highly correlated with the number of heading days in the field. Therefore, the optimum transplanting date was calculated according to the transplanting date in each area. When the accumulated temperature was 700℃, if floury rice was transplanted at the optimum transplanting date, the mean temperature was approximately 20℃. When the accumulated temperature was 900℃, the mean temperature was approximately 18℃. Under these conditions, the viviparity rates of Hangaru, Seolgeang, and Singil rice were lower than 10%. However, Baromi2 showed a high viviparity rate. These results suggest that the viviparity rate of Hangaru, Seolgeang, and Singil rice can be reduced by transplanting at the optimum transplanting date. However, further research is required for pinpointing the optimum transplanting date of Baromi2 rice.