• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.9
• /
• pp.34-44
• /
• 2016

This study is an experimental study about a facility for preventing the accumulation of floating debris at a bridge by flooding at a small river. Generally, structures installed at a small river are damaged frequently by floating debris during typhoons or localized rainfall events. On the other hand, there is no method available for preventing such damage. The facilities used in other countries to prevent such damage by the accumulation of floating debris include debris fins, deflectors, and sweeper. Among these facilities, the present study was conducted with a sweeper to investigate the damage-reducing capability through a real-scale accumulation experiment. A sweeper was installed in front of a bridge to bypass floating debris by self-rotation so that the floating debris may not be accumulate at the bridge. A small bridge model was prepared in a real-scale for the real-scale experiment. The accumulation reducing capability was compared through an accumulation experiment before and after the sweeper installation depending on the length of the debris and flow conditions. The result showed that the accumulation rate increased with increasing length of the debris or decreasing flow rate. The installation of a sweeper decreased the debris accumulation rate by a minimum of 55% to a maximum of 88% compared to the case without an installed sweeper. The result of the present study showed that the installation of a sweeper at a small river having a high potential of generating floating debris may help secure the stability of a bridge in the case of floating debris accumulation.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.23 no.1
• /
• pp.15-29
• /
• 2020

Recently, the incidence of flooding in Korea has decreased by the measures by central and local governments, however the scale of damage is increasing due to the improvement of living standard. One of the causes of such flood damage is natural causes such as rainfall exceeding the planned frequency of flood control under climate change. In addition, there are artificial causes such as encroachment of river spaces and management problems in upstream basins without consideration of downstream damage potential by regional development flood. In this study, in order to reduce the inundation damage caused by flooding of river, the situation at the time of inundation damage was reproduced by the detailed topographic data and 2D numerical model. Therefore, the effect of preparing various disaster prevention measures for the lowland was simulated in advance so that quantitative evaluation could be achieved. The target area is Taehwa river basin, where flooding was caused by the flooding of river waters caused by typhoon Chaba in October 2016. As a result of rainfall-discharge and two-dimensional analysis, the simulation results agree with the observed in terms of flood depth, flood arrival time and flooded area. This study examined the applicability of hydraulic analysis on river using two-dimensional inundation model, by applying detailed topographic data and it is expected to contribute to establish of disaster prevention measures.

• 한국지구과학회:학술대회논문집
• /
• 2005.09a
• /
• pp.199-206
• /
• 2005

지구과학은 실생활과 직접적으로 관련되거나 학생들이 친숙하게 생각하는 많은 개념들을 포함하고 있으며 이런 특성은 과학캠프나 자연탐사 활동에서 지구과학과 관련한 탐구주제가 학생들의 큰 호응을 얻는 사실을 설명할 수 있다. 하지만 정규 수업에서 이루어지는 지구과학 실험 수업은 교과서에 제시된 자료해석 위주의 실험이 많아 학생들의 흥미를 반감시키는 경우가 많으며 자료 측정과정에서 과학자가 느낄 수 있는 중요하고 귀중한 경험을 놓칠수 있다. 그런데 인터넷에서는 해양과 대기, 천문, 지질 각 분야에서 지속적으로 갱신되는 실시간 관측 자료를 제공해 주는 곳이 많으며 이 실시간 자료들을 고등학교의 지구과학 실험에 이용할 수 있도록 학습 프로그램을 개발하면 기존의 자료해석 실험이 가지는 한계를 극복하고 학생들의 지구과학에 대한 호응도를 높일 수 있으며 보다 다양한 탐구 능력을 향상 시킬 수 있다. 이러한 학습 프로그램의 특징은 탐구 중심 혹은 문제 해결 학습을 강조하는 현재의 교육 목표를 잘 반영할 수 있다. 본 연구의 목적은 인터넷에서 제공되는 지구과학 관련 실시간 자료들을 활용할 수 있는 고등학교 지구과학 학습 프로그램을 개발하고 이를 지원할 수 있는 홈페이지를 구축한 후 실제로 수업에 적용하여 교육적 효과를 확인하는 것이다. 연구 결과 실시간 자료를 이용하는 고등학교 학생들을 위한 지구과학 학습 프로그램을 12개의 주제에 대해서 완성했다. 먼저 지구과학실험 시간에 적용할 수 있는 2차시 분량의 학습 프로그램 6주제를 개발했는데 개발 주제는 '지진이 일어나고 있는 곳은 어디인가?', '진앙으로 판의 경계를 결정하기', '진앙의 위치를 찾아라', '암영대를 찾아라', '태양의 자전 주기를 측정하기', '태양활동' 이다. 각 주제별로 수업소개, 학습목표, 과정, 학습자료(학생 활동지, 기타 자료, 수업 내용과 관련한 실시간 자료 제공 사이트 목록), 평가 자료를 만들었다. 학생들의 활동 내용은 <지진이 일어나고 있는 곳은 어디인가?>의 주제를 예로 들면 학생들이 실시간으로 전 세계의 지진활동을 모니터하는 사이트에 접속하여 최근에 지진이 어디에서 일어났는지 알아보고 지난 30일 동안에 일어났던 규모 4 이상의 지진 자료를 다운 받아 세계 지도에 점으로 표시한다. 이 때 학생들은 손으로 진앙의 위치를 지도에 그리는 대신 엑셀의 그래프 기능을 이용하여 지도에 진앙의 위치를 나타내게 한다. 또 개인 과제 연구에 적용할 수 있는 학습 프로그램을 5가지 개발하여 학생들이 특정한 주제에 대하여 탐구 과제를 수행할 수 있게 했는데 개발된 주제는 '태양 활동으로 오로라 예측하기', '국제 우주 정거장을 찾아내자', '한반도 부근의 해양 기상과 해수의 물리적 상호 관계', '일기도 분석을 통한 태풍의 진로 예측', '우리 나라 조석 예측' 이다. 마지막으로 사이버 학습을 통해서 수업 시간의 제약 없이 과제 형태로 처치 가능한 학습 프로그램 개발 했는데 그 주제는 '태풍이 저위도에서 북상하는 이유?'이다. 개발된 프로그램 중 2차시 학습 프로그램은 과학고 중학생 영재반에게, 개인 탐구 과제는 과학고 1학년 학생들에게, 사이버 수업 형태는 과학고 2학년 학생에게 적용시켰다. 실시간 자료 활용을 지원하는 홈페이지를 만들어 자료 제공 사이트에 대한 메타 자료를 데이터베이스화했으며 이를 통해 학생들이 원하는 실시간 자료를 검색하여 찾을 수 있고 홈페이지를 방분했을 때 이해하기 어려운 그래프나 각 홈페이지가 제공하는 자료들에 대한 처리 방법을 도움말로 제공받을 수 있게 했다. 실시간 자료들을 이용한 학습은 학생들의 학습 의욕과 탐구 능력을 향상시켰으며 컴퓨터 활용 능력과 외국어 자료 활용 능력을 향상 시키는데도 도움을 주었다.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.26 no.5
• /
• pp.506-513
• /
• 2020

Due to climate change, there is an increasing risk of complex (hybrid) disasters, comprising rising sea-levels, typhoons, and torrential rains. This study focuses on Marine City, Busan, a new residential city built on a former landfill site in Suyeong Bay, which recently suffered massive flood damage following a combination of typhoons, storm surges, and wave overtopping and run-up. Preparations for similar complex disasters in future will depend on risk impact assessment and prioritization to establish appropriate countermeasures. A framework was first developed for this study, followed by the collection of data on flood prediction and socioeconomic risk factors. Five socioeconomic risk factors were identified: (1) population density, (2) basement accommodation, (3) building density and design, (4) design of sidewalks, and (5) design of roads. For each factor, absolute criteria were determined with which to assess their level of risk, while expert surveys were consulted to weight each factor. The results were classified into four levels and the risk level was calculated according to the sea-level rise predictions for the year 2100 and a 100-year return period for storm surge and rainfall: Attention 43 %, Caution 24 %, Alert 21 %, and Danger 11 %. Finally, each level, indicated by a different color, was depicted on a complex disaster risk map.

• Journal of Korea Water Resources Association
• /
• v.46 no.6
• /
• pp.655-666
• /
• 2013

Lately, intensity and frequency of natural disasters such as flood are increasing because of abnormal climate. Casualties and property damages due to large-scale floods such as Typhoon Rusa in 2002 and Typhoon Maemi in 2003 rapidly increased, and these show the limits of the existing disaster prevention measures and flood forecasting systems regarding irregular climate changes. In order to efficiently respond to extraordinary flood, it is important to provide effective countermeasures through an inundation model that can accurately simulate flood inundation patterns. However, the existing flood inundation analysis model has problems such as excessive take of analysis time and accuracy of the analyzed results. Therefore, this study conducted a flood inundation analysis by using the Gerris flow solver that uses quadtree grid, targeting the Baeksan Levee in the Nakdong River Basin that collapsed because of a concentrated torrential rainfall in August, 2002. Through comparisons with the FLUMEN model that uses unstructured grid among the existing flood inundation models and the actual flooded areas, it determined the applicability and efficiency of the quadtree grid-based flood inundation model of the Gerris flow solver.

• Journal of Korean Society of Forest Science
• /
• v.77 no.3
• /
• pp.276-282
• /
• 1988

Many landslides occurred at the western part of Gyeongnam province by the typhoon No. 875. Their conditions and causes were investigated and were summarized as follows : The total number of landslide occurred was 2,490 and its area was 156.53ha. In about 94% of landslides and about 97% of landslides area occurred in 3 counties, Sancheong, Hamyang and Geochang. The landslides smaller than 0.01ha was 49% of the total indicating that about half of them were the small landslides. Considering homogenous topography amount of precipitation and forest type landslides appeared to be mainly has a high affected by the geological factor because the landslides mainly occurred in the deep weathered soil of igneous rock. The landslides occured on concave slopes of 31 to $35^{\circ}$ in steepness with low crown density. In the area of the deep weathered soil, landslide likely occur repeatedly. Therefore, regular erosion control works are recommended in the area of pos for disaster prevention and counter-measures.

• Journal of Korea Water Resources Association
• /
• v.43 no.8
• /
• pp.695-707
• /
• 2010

The frequency and size of typhoon and local severe rainfall are increasing due to the climate change and the damage also increasing from typhoon and severe rainfall. The flood forecasting and warning system to reduce the damage from typhoon and severe rainfall needs forecasted rainfall using radar data and short-term rainfall forecasting model. For this reason, this study examined the applicability of short-term rainfall forecast using translation model with weather radar data to point out that the utilization of flood forecasting in Korea. This study estimated the radar rainfall using Least-square fitting method and estimated rainfall was used as initial field of translation model. The translation model have verified accuracy of forecasted radar rainfall through the comparison of forecasted radar rainfall and observed rainfall quantitatively and qualitatively. Almost case studies showed that accuracy is over 0.6 within 4 hours leading time and mean of correlation coefficient is over 0.5 within 1 hours leading time in Kwanak and Jindo radar site. And, as the increasing the leading time, the forecast accuracy of precipitation decreased. The results of the calculated Mean Area Precipitation (MAP) showed forecast rainfall tend to be underestimated than observed rainfall but the correlation coefficient more than 0.5. Therefore it showed that translation model could be accurately predicted the rainfall relatively. The present results indicate that possibility of translation model application of Korea just within 2 hours leading forecasted rainfall.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.32 no.6
• /
• pp.373-383
• /
• 2020

In this study we established an operational storm-surge system for the northwestern pacific ocean, based on the NEMO (Nucleus for European Modeling of the Ocean). The system consists of the tide and the surge models. For more accurate storm surge prediction, it can be completed not only by applying more precise depth data, but also by optimal parameterization at the boundaries of the atmosphere and ocean. To this end, we conducted several sensitivity experiments related to the application of available bathymetry data, ocean bottom friction coefficient, and wind stress and air pressure on the ocean surface during August~September 2018 and the case of typhoon SOULIK. The results of comparison and verification are presented here, and they are compared with POM (Princeton Ocean Model) based Regional Tide Surge forecasting Model (RTSM). The results showed that the RTSM_NEMO model had a 29% and 20% decrease in Bias and RMSE respectively compared to the RTSM_POM model, and that the RTSM_NEMO model had a lower overall error than the RTSM_POM model for the case of typhoon SOULIK.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.8 no.6
• /
• pp.93-100
• /
• 2008

Dense of population construction and high density of skyscraper, and geological characteristics caused natural disasters(e.g. typhoon, tsunami, flood, storm, earthquake, etc.) and manmade disasters(e.g. fire, collapse, explosion, traffic accident, etc.). the extent and scale of the disaster are getting larger. To cope with such problems, Busan City has established the basic plan to secure the life and property of the citizens through model strategy and design of Ubiquitous-Safety Busan. This study quantitatively analyzed the ripple effect on local economy through the fulfillment of Ubiquitous-Safety. The production inducing effect of 250 billion won directly and indirectly can be estimated due to the realization of Ubiquitous-Safety. The value added effect of 115 billion won can be estimated. the employment effect of 5,580 persons can be generated with income effect of 51 billion won.

• Explosives and Blasting
• /
• v.29 no.2
• /
• pp.1-12
• /
• 2011

Progressive collapse analyses of high-rise buildings subjected to abnormal loading such as fires, impacts, earthquakes, typhoon, bomb blasts etc. are intended. However it is difficult to perform collapse experiments of the real scale building to determine the capacity of the structure under an extreme loading events. In this study, collapse behavior of a 15 story RC structure building loaded by external explosion pressures were simulated using Extreme Loading Structures (ELS) software. The standoff distance between the RC building and explosives of 1500 kg was 1, 2, 5, 10, and 15 meters. The explosive demolition analysis techniques based on removal of partial support structures following blast scenario was adapted to investigate the transition process of progressive collapse-local damage.