• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.5
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• pp.319-325
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• 2012

A new formulae for the estimation of the exposure duration in the inter-tidal zone are developed. The exposure duration is one of the most important factors influencing the habitat distribution of the benthic organisms. The formulae can estimate the exposure duration only using the four major tidal harmonic constants available in almost coastal areas. It is easier than the existing method using the frequency analysis of the hourly tidal elevation data. The estimation results by using the formulae suggested in this study are compared with the value by using the observed tidal elevation data analysis in the west coast, Korea. The mean RMS (root-mean squared) errors ranged form 0.8 to 1.4%. It can be used to simply estimate the accurate exposure duration in the region not having the longterm hourly tidal elevation data.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2116-2117
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• 2011

최근 인공적인 환경오염 및 급격하게 변하는 대기의 불안정한 요소 등에 의해 낙뢰를 동반한 게릴라성 폭우가 우리나라 전반에 걸쳐 빈번하게 발생하고 있으며 이러한 피해유형을 살펴보면 폭우에 의한 침수피해, 직 간접뢰에 의한 낙뢰피해 등을 들 수 있다. 후자인 낙뢰에 의한 피해는 인명 및 구조물에 대한 피해도 있겠지만 최근 정보통신의 기술발전에 의한 기계 및 전기 그리고 전자설비에 적용된 약전압계통의 설비 피해가 속출하고 있는 실정이다. 대부분의 K-water 사업장이 다른 구조물 보다 높은 곳에 위치해 있듯이 대불정수장 및 원격감시제어사업장(목포가압장, 대불취수장)은 산 정상 부근에 위치해 있어 뇌운에 의한 직, 간접뢰를 맞을 확률이 비교적 높으며 계측제어설비 및 설비운영을 위한 계측, 감시, 제어설비 낙뢰에 노출되어 있다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.1
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• pp.107-118
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• 1979

The critical low temperature of death under submerged soil was -5^\circ C for the underground tuber of Cyperus serotinus while the vegetative organ (tuber or bulb) of Sagittaria pygmaea and Potamogeton distinctus -6^\circ C, -7^\circ C respectively. On the critical high temperature of death in water bath with 45^\circ C. Potamogeton distinctus and Sagittaria pygmaea were 1 hour, 24 hours, but Cyperus serotinus did not die. When vegetative organs of perenivial weeds setted on the soil surface, the propagation organ of Potamegeton distinctus did not die by desication in 17% of soil moisture, but Cyperus serotinus and Sagittaria pygmaea were dead within 2 to 3 hours in 25^\circ C of soil moisture.

• Journal of Conservation Science
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• v.28 no.4
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• pp.329-341
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• 2012

Magai Wareiishi Jizo (Buddhist statue carved on rock surface) is close to shoreline and a part of rock block is periodically immersed by seawater. Rock material of the Wareiishi-jizo statue is composed mainly of medium or coarse-grained biotite granite and very durable. However, physical properties of the rock have been changed according to the complex interactions of the salt solution and surrounding environment. Exfoliation of the rock surface is a serious condition by salt crystallization. Exfoliation (14.6%) is concentrated on the upper part of the rock block with mainly boundary of seawater as the center. On the other hand, lower part of the rock block show black layers by contaminants deposition. In addition, brown discoloration and biological contaminants is overlapped. Rock surface show high discoloration rate of 50.5% (black discoloration, 29.2% > yellow discoloration, 14.1% > brown discoloration, 4.4% > green discoloration, 2.9%). Upper part of the rock block had a lot of change in the physical properties than lower part that is immersed by seawater. In particular, surface properties of the rock block was very weak state at the boundary surface of seawater permeation.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.453-453
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• 2011

21세기에 들어 홍수의 규모가 대형화 되었고, 그 발생빈도 및 강도도 증가하고 있다. 최근에는 지구온난화가 지속화되면서 전 세계적으로 높은 강도의 기상이변들이 속출하고 있고, 이러한 이상기후에 따른 태풍, 집중호우 등의 대규모 호우로 인해 댐 및 제방 등의 수공구조물 붕괴와 같은 비상상황이 초래 될 수 있다. 이와 같은 피해들을 통해 홍수 침수 범위의 예측, 분석을 통한 홍수위험 및 다양한 홍수위험지도 작성의 필요성이 대두되었고, 실제로 국가 차원의 홍수위 험지도가 제작되고 있다. 특히, 홍수 위험도 분석에 있어서 홍수에 노출된 지역의 인구수, 홍수에 노출된 지역에서의 경제적 활동의 형태, 홍수가 발생했을 때 2차적 피해를 불러올 수 있는 설비 등을 나타내는 홍수 취약도(Flood Vulnerability)에 대한 정량적 평가는 홍수위험지표 및 홍수위험강도 등에 의한 Flood Risk 개념을 기반으로 한 홍수위험지도 제작을 위해 매우 중요한 사항이라 할 수 있다. 그러나 현재까지의 홍수취약도 산정방법은 방법론적인 면에 있어 다소 단순하고, 직관에 의한 위험도의 분류가 이루어지고 있는 실정이다. 또한 취약도 지표의 산정과정이 전문가의 의견에 의존하는 경우가 많아 홍수 취약도 선정과정과 가중치 결정과정에 전문가들의 주관이 개입되는 등 홍수위험지표의 정량화에 어려움을 겪는 경우가 많다. 본 연구에서는 위와 같은 문제를 극복하기 위해 Flood Risk Mapping 기술의 적용에 있어 중요한 요소인 홍수취약도를 다기준의사결정법에 의해 산정하고, 국내 낙동강 유역에 대해 행정구역별로 세분화된 홍수위험지도 제작을 위한 취약도 지표를 산정하고자 하였다. 이를 위해 다기준의사결정법중의 하나 인 PROMEETEE와 ELECTRE를 이용하여 민감도, 노출도, 저감성 지표를 낙동강 유역에 대해 정량화하여 도시하였다. 본 연구결과를 통해 홍수위험지표 및 지수들의 결합에 대한새로운 방법론을 제시하고, 그에 따른 지도화 기법을 확립할 수 있을 것으로 기대된다.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.4
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• pp.482-487
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• 2008

In case of flooding, the underwater flight vehicle (UFV) executes the blowing by blowing ballast tanks off using high pressure air (HPA), while it also uses control planes and a propulsion unit to reduce the overshoot depth caused by a flooding and blowing sequence. However, the conventional whole HPA blow-off method lets the body on the surface after blowing despite slight flooding. This results in the unnecessary mission failure or body exposure. Therefore, it is necessary to keep the body at the near surface by the blowing control while reducing the overshoot depth. To solve this problem, an adaptive blowing control algorithm, which is based on the decomposition method expanding the expert knowledge in depth control and the adaptive method using fuzzy basis function expansion (FBFE), is proposed. To verify the performance of the proposed algorithm, the blowing control of UFV is performed. Simulation results show that the proposed algorithm effectively solves the problems in the UFV blowing control system online.

• Journal of Wetlands Research
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• v.12 no.3
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• pp.129-144
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• 2010

We have studied the changes of the environmental and vegetational factors according to the hydro-seral stages in the shoreline of the lagoons, Korea. We have divided seral stages into 7 stages from open water stage to the stratified forest stage considering as the characteristics of water body, dominance of submerged and emergent plant, and development of the shrub, subtree and tree layer. According to the successional stage, water depth gradually decreased and water quality changed from seawater to brackish water and from brackish water to fresh water, organic matter in a soil layer gradually increased, and the litter layer grew up. As the development of the vegetation structure, the life-form of the vascular plants changed as follows; open water ${\rightarrow}$ submerged plant and floating-leaved plant ${\rightarrow}$ emergent plant and submerged plant ${\rightarrow}$ emergent plant ${\rightarrow}$ emergent plant, mesophyte and scrub ${\rightarrow}$ mesophyte. In the late seral stage, the 3 different forest types were established by the water retention or drainage and nutrient accumulation of the soil layer. Salix dominant forest developed in the wetted sites, the forest type dominated by Pinus thunbergii, Carex pumila and mesophytes developed in the well drained sites causing by sand substrate, and the forest type dominated by the planted or ruderals such as Pinus densiflora, Robinia psedo-acacia, Festuca ovina, Setaria viridis ect. developed in the sites composed of forest soil introduced by artificial reclamation.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.225-225
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• 2019

건물, 차량, 사회인프라시설과 달리 농작물이란 물리적인 시설이 아닌 농업경제 활동의 결과물로서 최종적으로 판매를 통해 수익을 창출하는 행위에서 재난으로 인하여 지장을 받게 되는 경제적 피해가 고려되어야 한다. 이를 위해 본 연구는 홍수로 인한 농작물 피해를 "생산비 매몰비용"과 "순수익 손해"를 농작물 피해추정의 척도로 하였다. 생산비 매몰비용이란 경작시작부터 피해발생까지 투입된 생산비의 회수불가에 따른 피해이며, 순수익 손해란 피해발생에 따른 기대 순수익 하락에 따른 피해를 의미한다. 다양한 작물 가운데 10종의 대표작물을 선택하고, 각 작물의 표준생산비와 표준순수익을 농업생산 및 수익과 관련한 통계자료로부터 결정하였다. 이로부터 생육경과율과 홍수 발생시기(6~9월)를 고려하여 월별 투입생산비 및 기대순수익을 결정하였다. 대상지역 내 재난에 노출된 작물정보를 정의하는 농작물 인벤토리는 농림축산식품부에서 제작된 스마트 팜 맵(농경지 전자지도)을 활용하였고, 다양한 작물이 혼재된 밭의 경우 농업면적조사 결과를 토대로 결정한 밭작물 재배현황비를 고려하였다. 홍수에 따른 취약성을 설명하는 농작물 손상함수는 영향인자는 침수심, 침수기간이며, 이를 기준으로 한 손상함수는 농림부의 농업재해피해조사요령과 일본 치수경제조사메뉴얼을 참고하여 제시하였다. 본 연구에서 제시한 농작물 피해 추정 방법은 기존 방법인 다차원 홍수피해산정법(MD-FDA)과 비교할 때 대표작물의 현실화, 국내 실정을 고려한 손상함수, 그리고 면적 기반의 원단위를 사용함으로써 실무적으로 명확하고 실용적으로 사용될 것으로 기대된다.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.3
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• pp.119-136
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• 2012

The goal of this study is to apply the IPCC(Intergovernmental Panel on Climate Change) concept of vulnerability to climate change and verify the use of a combination of vulnerability index and fuzzy logic to flood vulnerability analysis and mapping in Seoul using GIS. In order to achieve this goal, this study identified indicators influencing floods based on literature review. We include indicators of exposure to climate(daily max rainfall, days of 80mm over), sensitivity(slope, geological, average DEM, impermeability layer, topography and drainage), and adaptive capacity(retarding basin and green-infra). Also, this research used fuzzy model for aggregating indicators, and utilized frequency ratio to decide fuzzy membership values. Results show that the number of days of precipitation above 80mm, the distance from river and impervious surface have comparatively strong influence on flood damage. Furthermore, when precipitation is over 269mm, areas with scare flood mitigation capacities, industrial land use, elevation of 16~20m, within 50m distance from rivers are quite vulnerable to floods. Yeongdeungpo-gu, Yongsan-gu, Mapo-gu include comparatively large vulnerable areas. This study improved previous flood vulnerability assessment methodology by adopting fuzzy model. Also, vulnerability map provides meaningful information for decision makers regarding priority areas for implementing flood mitigation policies.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.5
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• pp.492-501
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• 2007

Coastal disasters have become one of the most important issues in every coastal country. In Korea, coastal disasters such as storm surge, sea level rise and extreme weather have placed many coastal regions in danger of being exposed or damaged during subsequent storms and gradual shoreline retreat. A storm surge is an onshore gush of water associated with a tow pressure weather system, typically in typhoon season. However, it is very difficult to predict storm surge height and inundation due to the irregularity of the course and intensity of a typhoon. To provide a new scheme of typhoon damage prediction model, the scenario which changes the central pressure, the maximum wind radius, the track and the proceeding speed by corresponding previous typhoon database, was composed. The virtual typhoon scenario database was constructed with individual scenario simulation and evaluation, in which it extracted the result from the scenario database of information of the hereafter typhoon and information due to climate change. This virtual typhoon scenario database will apply damage prediction information about a typhoon. This study performed construction and analysis of the simulation system with the storm surge/coastal inundation model at Masan coastal areas, and applied method for predicting using the scenario of the storm surge.