• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.636-639
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• 2007

The frequently flooded area has been known as very vulnerable area. This area has nature disasters such as typhoon, storm and flood almost every year. The purpose of this study is to develop a management system for frequently flooded area by Web based. So this system is possible to disaster management which irrespective of time and place. Through this system, general user can easily retrieve status information and obtain that in visual way such as maps. graph, and texts if they have only certain web browsers.

• Journal of Korea Water Resources Association
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• v.49 no.6
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• pp.519-528
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• 2016

Frequently torrential rain is occurred by climate change and urbanization. Urban is formed with road, residential and underground area. Without detailed topographic flooded analysis consideration can take a result which are wrong flooded depth and flooded area. Especially, flood analysis error of population and assets in dense downtown is causing a big problem for establishments and disaster response of flood measures. It can lead to casualties and property damage. Urban flood analysis is divided into sewer flow analysis and surface inundation analysis. Accuracy is very important point of these analysis. In this study, to confirm the effects of the elevation data precision in the process of flooded analysis were studied using 10m DEM, LiDAR data and 1:1,000 digital map. Study area is Dorim-stream basin in the Darim drainage basin, Sinrim 3 drainage basin, Sinrim 4 drainage basin. Flooding simulation through 2010's heavy rain by using XP-SWMM. Result, from 10m DEM, shows wrong flood depth which is more than 1m. In particular, some of the overflow manhole is not seen occurrence. Accordingly, detailed surface data is very important factor and it should be very careful when using the 10m DEM.

• Korean Journal of Remote Sensing
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• v.36 no.4
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• pp.627-635
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• 2020

With the increasing severity of climate change, intense torrential rains are occurring more frequently globally. Flooding due to torrential rain not only causes substantial damage directly, but also via secondary events such as landslides. Therefore, accurate and prompt flood detection is required. Because it is difficult to directly access flooded areas, previous studies have largely used satellite images. Traditionally, water indices such asthe normalized difference water index (NDWI) and modified normalized difference water index (MNDWI) which are based on different optical bands acquired by satellites, are used to detect floods. In addition, as flooding likelihood is greatly influenced by the weather, synthetic aperture radar (SAR) images have also been used, because these are less influenced by weather conditions. In this study, we compared flood areas calculated from SAR images and water indices derived from Landsat-8 images, where the images were acquired at similar times. The flooded area was calculated from Landsat-8 and Sentinel-1 images taken between the end of May and August 2019 at Lijiazhou Island, China, which is located in the Changjiang (Yangtze) River basin and experiences annual floods. As a result, the flooded area calculated using the MNDWI was approximately 21% larger on average than that calculated using the NDWI. In a comparison of flood areas calculated using water indices and SAR intensity images, the flood areas calculated using SAR images tended to be smaller, regardless of the order in which the images were acquired. Because the images were acquired by the two satellites on different dates, we could not directly compare the accuracy of the water-index and SAR data. Nevertheless, this study demonstrates that floods can be detected using both optical and SAR satellite data.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.620-623
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• 2007

The purpose of this study is developing a disaster prevention information system using Internet GIS to manage disaster information more efficiently and timely. This system has good potential with environment of Internet which has appropriate characteristics of rapidity, wide reach, generality, cost effectivity for disaster management. With this system, general user can easily retrieve disaster information with visuality such as maps. graphs, and texts just by using web browsers. Hence the need of developing Internet GIS system for disaster prevention is growing in these days.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1575-1579
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• 2009

풍수해 피해를 경감하기 위해 지리정보시스템을 이용하여 시간적, 공간적 분석을 통해 홍수범람 범위와 배수시간을 분석 검토하여 상습침수지역의 침수피해를 저감시키는 방법을 모색하고자 하였다. 본 연구에서는 상습침수지역인 형산강수계 경주시 현곡면 소유역을 대상지역으로 선정하고 지리정보시스템과 연계하여 침수범위와 홍수심, 현장조건에 따른 배제시간 등을 확인하기 위해 HEC- GeoRAS와 HEC-RAS를 이용하여 침수범람 및 배수특성분석을 실시하였다. 그 결과 대상지역의 빈도별 홍수위 분석에 따른 홍수범람 위험지역 산정과 배수조건을 제시하고 상습침수지역에 홍수발생시 인명과 재산피해를 대비한 효과적인 홍수피해 경감대책 수립을 위한 범람모의를 실시하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.834-839
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• 2006

본 연구는 하천연안에 위치한 소지류 하구부의 제방파괴로 인하여 외수위의 영향을 받는 제내지가 본류하도의 배수(back water)영향과 내수유입으로 침수역이 발생하게 되며, 이때에 홍수범람역의 범위와 배수시간을 분석.검토하여 침수피해를 저감시키는 방법을 모색하고자 하였다. 소하천유역의 침수상태해석을 위해 제내지측 침수역을 지류하도로 취급하여 두 개의 하천이 합류하는 조건으로 분석을 실시하였다. 이때 HEC-RAS를 이용하여 침수구역의 부정류 해석을 실시하였으며, 제내지의 침수 및 배수특성을 파악하기 위하여 본류하도의 홍수규모 즉, 홍수량(위)에 따른 제내지 침수역의 배수영향범위를 추정하였고 파제부의 내수배제 시간을 해석하여 침수피해를 경감시킬 수 있는 파제부의 구조적인 개선방안을 분석.검토하였다. 그 결과 파제로 인하여 제내지가 본류하도의 외수위에 영향을 받으면서 제내지에 침수가 발생하는 소하천유역에서는 파제부의 범위에 따라 내수배제 능력과 배수영향을 동시에 분석하여 제내지에서 효과적인 내수배제능력을 가지면서 배수영향을 최소화하는 최적의 조건을 얻을 수 있었다.

• Journal of Ocean Engineering and Technology
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• v.38 no.3
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• pp.124-136
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• 2024

As the number of offshore wind-power installations increases, collision accidents with vessels occur more frequently. This study investigates the risk of collision damage with operating vessels that may occur during the operation of an offshore wind turbine. The floater used in the collision study is a 15 MW UMaine VolturnUS-S (semi-submersible type), and the colliding ships are selected as multi-purpose vessels, service operation vessels, or anchor-handling tug ships based on their operational purpose. Collision analysis is performed using ABAQUS and substantiation is performed via a drop impact test. The collision analyses are conducted by varying the ship velocity, displacement, collision angle, and ship shape. By applying this numerical model, the extent of damage and deformation of the collision area is confirmed. The analysis results show that a vessel with a bulbous bow can cause flooding, depending on the collision conditions. For damage caused by collision, various collision angles must be considered based on the internal stiffener arrangement. Additionally, the floater can be flooded with relatively small collision energy when the colliding vessel has a bulbous bow.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.613-613
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• 2015

최근 전 지구적인 온난화로 인한 이상기후에 따라 강수량이 증가하고, 특정지역에만 국한되어 집중적으로 비가 내리는 국지성 집중호우의 발생 빈도가 증가하여 이로 인한 극한 홍수나 강우로 인한 산사태 등의 재해가 반복적으로 발생하고 있다. 홍수는 재산 및 인명에 이르기까지 막대한 피해를 야기한다는 점에서 이를 대비하기 위한 방안이 필수적이므로 국가적인 차원에서 홍수피해를 경감시키기 위한 여러 가지 구조적 또는 비구조적 대책들을 제시하고 있지만, 정확한 기상 변화의 예측이 어렵고 다양한 유발 원인들로부터 비롯된 홍수에 모두 대응할 수 있는 통합 대책 마련이 어려운 실정이다. 즉, 사전예방보다는 피해 복구에만 중점을 두고 있기 때문에 홍수 발생 유역의 지역적인 홍수피해 특성을 반영하지 못할 뿐만 아니라 어느 지역이 상대적으로 홍수피해의 위험성이 높은 지역인지도 파악하기 어렵다. 따라서, 본 연구에서는 도시홍수피해 유형인 내수침수피해와 외수침수피해의 유형에 따라 사례들을 조사하고 관련문헌들로부터 도시 홍수 취약성 평가를 위한 대표적 인자들을 도출하였다. 도출된 인자들을 각각 IPCC의 취약성 평가 프레임에 따라 기후노출, 민감도 그리고 적응능력으로 구분하고 도시 상습침수지역인 도림천 유역을 시범 지역으로 하여 도시홍수 취약성 평가를 위한 지수를 개발하고자 한다. 본 연구를 통하여 향후 도시홍수피해의 잠재적 위험성이 높을 것으로 판단되는 유역에 대한 활용방안을 제시하고 유역의 특성 및 중요도에 따른 치수사업의 우선순위를 결정하는 등 유역의 특성을 반영한 구체적 적응정책의 방향성을 세우는데 기초자료로 제공될 수 있으며, 도시홍수로 인한 인명 및 재산의 피해를 최소화 하는 것에 목적이 있다.

• Journal of Korea Water Resources Association
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• v.50 no.3
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• pp.169-179
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• 2017

Recently, due to global warming and climate change in Korea, local heavy storm occurs frequently. In this study, the risky areas for flooding in urban areas are analyzed for flood inundation based on two-dimensional urban flood runoff model (XP-SWMM) focusing on coastal high flood-risk urban areas. In addition, the MCDM (Multi-Criteria Decision Making) technique is utilized in order to establish the flood defense structural measures. The alternative flood reduction method are compared and the optimum flood defense measures are selected. A simulation model was used with three structural flood prevention measures (drainage pipe construction, water detention, flood pumping station). In order to decrease the flooding area, flood assessment criteria are suggested (flooded area, maximum inundation depth, damaged residential area, construction cost). Priorities of alternatives are determined by using compromise programming. As a result, the optimal flood defence alternative suggested for Janghang Zone 1 is flood pumping station and for Janghang Zone 2, 3 are drainage pipe construction.

• Journal of Korea Water Resources Association
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• v.51 no.2
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• pp.121-129
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• 2018

Rainfall falling in the impervious area of the cities flows over the surface and into the stormwater pipe networks to be discharged from the catchment. Therefore, it is very important to determine the size of stormwater pipes based on the peak discharge to mitigate urban flood. Climate change causes the severe rainfall in the small area, then the peak rainfall can not be discharged due to the capacity of the stormwater pipes and causes the urban flood for the short time periods. To mitigate these type of flood, the large stormwater pipes have to be constructed. However, the economic factor is also very important to design the stormwater pipe networks. In this study, 4 urban catchments were selected from the frequently flooded cities. Rainfall data from Seoul and Busan weather stations were applied to calculate runoff from the catchments using SWMM model. The characteristics of the peak runoff were analyzed using linear regression model and the 95% confidence interval and the coefficient of variation was calculated. The drainage density was calculated and the runoff characteristics were analyzed. As a result, the drainage density were depended on the structure of stormwater pipe network whether the structures are dendritic or looped. As the drainage density become higher, the runoff could be predicted more accurately. it is because the possibility of flooding caused by the capacity of stormwater pipes is decreased when the drainage density is high. It would be very efficient if the structure of stormwater pipe network is considered when the network is designed.