• 조명전기설비학회논문지
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• 제28권12호
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• pp.38-44
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• 2014

The photovoltaic power system is performing power generation by being installed in outdoors. Therefore it has the characteristics affected by environmental factors. In particular, if the solar power generation facility connected to the grid, the power can be generated continuously in a state of being secured operating voltage of the inverter and solar irradiation. In that case, if an abnormal situation such as flooding or heavy rains has occur, the possibility of electric shock or damage of facilities due to current leakage or a floating matters is present. In this paper, we performed electrical safety assessment about the connection part, junction box and cable of the solar module when the solar power system was flooded. we also assessed whether or not the leakage current is occurred in case of the cable was damaged. As a result, in case of the leakage current is large, we can be known that it is the risk of electric shock as well as cause of inverter damage.

• 한국해양공학회지
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• 제36권6호
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• pp.364-379
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• 2022

Coastal communities have been vulnerable to extreme coastal flooding induced by hurricanes and tsunamis. Many studies solely focused on the overland flow hydrodynamic and loading mechanisms on individual inland structures or buildings. Only a few studies have investigated the effects of flooding mitigation measures to protect the coastal communities represented through a complex series of building arrays. This study numerically examined the performance of flood-mitigation measures from tsunami-like wave-induced overland flows. A computational fluid dynamic model was utilized to investigate the performance of mitigation structures such as submerged breakwaters and seawalls in reducing resultant forces on a series of building arrays. This study considered the effects of incident wave heights and four geometrically structural factors: the freeboard, crest width of submerged breakwaters, and the height and location of seawalls. The results showed that prevention structures reduced inundation flow depths, velocities, and maximum forces in the inland environment. The results also indicated that increasing the seawall height or reducing the freeboard of a submerged breakwater significantly reduces the maximum horizontal forces, especially in the first row of buildings. However, installing a low-lying seawall closer to the building rows amplifies the maximum forces compared to the original seawall at the shoreline.

• 한국멀티미디어학회논문지
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• 제17권4호
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• pp.478-489
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• 2014

Recently, flood damage by frequent localized downpours in cities are on the increase on account of abnormal climate phenomena and growth of impermeable area by urbanization. In this study, we are focused on flooding on roads which is the basis of all means of transportation. To calculate real-time accumulated rainfall on a road link, we use the Coefficient of Correlation Weighting method (CCW) which is one of the revised methods of missing rainfall as we consider a road link as a unobserved rainfall site. CCW and real-time accumulated rainfall entered through the Internet are used to estimate the real-time rainfall on a road link. Together with the real-time accumulated rainfall, flooding history, rainfall range causing flooding of a road link and frequency probability precipitation for road design are used as factors to determine the Flood Risk Index on roads. We simulated two cases in the past, July, 7th, 2009 and July, 15th, 2012 in Busan. As a result, all of road links included in the actual flooded roads at that time got the high level of flood risk index.

• Journal of information and communication convergence engineering
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• 제10권4호
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• pp.329-336
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• 2012

For designing broadcast protocols in mobile ad hoc networks (MANETs), one of the important goals is to reduce the rebroadcast packets redundancy while reaching all the nodes in network. In this paper, we propose a probabilistic broadcasting mechanism based on selfishness and additional coverage in MANETs. Our approach dynamically adjusts the rebroadcast probability according to the extra covered area and number of neighbor nodes. By these two factors, mobile hosts can be classified into three groups: normal, low selfishness, and high selfishness groups. The nodes in the normal group forward packets for other nodes with high probability, whereas the nodes in the low selfishness group rebroadcast packets with low probability and the nodes in the high selfishness group do not rebroadcast packets. We compared our approach with simple flooding and the fixed probabilistic approach. The simulation results show that the proposed schemes can significantly reduce the number of retransmissions by up to 40% compared simple flooding and fixed probabilistic scheme without significant reduction in the network reachability and end-to-end packet delay.

• 한국유기농업학회지
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• 제21권4호
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• pp.501-522
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• 2013

This study has performed comparative analysis on benefit indicators in agricultural irrigation and drainage project cases between Korea and Japan. The irrigation and drainage project with publicity should do economic analysis of direct benefit factors as well as indirect benefit factors. However, traditional economic evaluations are used that benefit factors are lack of consistency and focused on direct benefits. Therefore, the purpose of this study was to develop indicators for the economic evaluation of irrigation and drainage projects. We conducted a case study between Korea and Japan. The resulting benefit factors was divided into direct factors and indirect factors. The direct benefit factors were increase in income, cost savings. The indirect benefit factors were protection of property due to flooding, agricultural promotion, aesthetic improvement. The implications of this study are that the indicators of economic analysis can be evaluated and easily applied. Moreover, these indicators could promote the feasibility of economic analysis.

• 한국방재안전학회논문집
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• 제13권2호
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• pp.53-63
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• 2020

본 연구에서는 2차원 흐름 해석 모형인 Hydro_AS-2D 모형을 이용하여 해수면 상승과 극한 홍수 발생 시 창원시 성산구 및 의창구 일대의 침수피해 상황을 모의하고, 그 결과를 3차원 지형 상에 표출한 후 BIM 기술을 이용하여 최적 대피경로를 도출하였다. 기후변화는 홍수재해 측면에서 크게 두 가지 요소에 영향을 미치는데 해수면 상승과 극한 강우사상의 증가이다. 해수면 상승은 그 자체만으로 연안지역에 해수가 범람하여 침수현상을 유발하는 영향을 미칠 수 있을 뿐 아니라 하천의 기점 홍수위를 상승시켜 하천 전체에 걸쳐 홍수위 상승을 유발한다. 본 연구에서는 기후변화에 의한 해수위 상승과 태풍에 의한 폭풍해일에 의한 해수위 상승, 그리고 태풍에 의한 극한 강우사상을 모의조건으로 설정하였다. 창원시의 지형공간정보와 하천정비기본계획의 하천횡단 정보를 이용하여 유역전체의 3차원 공간정보로 구성하고 이를 수치모형화 하였다. 연구대상지역은 BIM 기술을 이용하여 3차원 지형정보 상에 건물의 층고, 대피소 위치 등의 정보를 가지고 있는 3차원 도시정보모델로 구축하였으며, 수치모의 결과를 이 모델 상에 표출하고 대피계획을 위한 분석에 사용하였다. 침수발생 시 대피경로는 시간에 따른 침수 범위의 변화에 따라 대피소로의 경로를 설정하는 알고리즘에 의해 결정되며, 설정된 경로는 직관적인 3차원 공간정보 상에 표출되어 사용자에게 제공된다.

• 생태와환경
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• 제37권1호통권106호
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• pp.87-95
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• 2004

부산에 위치한 수영천과 석대천을 1997견 10월부터 1998년 9월까지 월별 정기 조사하여 강우, 수온 및 기온에 따른 군집동태를 연구하였다. 조사하천에서 깔따구류와 빈모류가 우점하여 저서성 대형무척추동물이 다양하게 출현하지 않았다. 수온의 증가는 두 우점군의 풍부도와 생체량을 증가시키는 역할을 하는 반면 잦은 강우는 유실효과를 유발하였다. 온도가 $15^{\circ}C$ 이하였던 10월과 2월 동안 석대천은 빈모류가 수영천에서는 다양한 분류군의 출현을 보였다. 온도가 크게 올라간 3월에 석대천과 수영천은 빈모류와 갈따구류의 증가가 나타났다. 그러나 4월에 큰 강우가 작용하여 석대천과 수영천에서 우점을 이루었던 빈모류와 깔따구류가 감소하였다. 집중강우와 기온상승이 이루어진 6월 이후 적대천은 강우로 오히려 증가되고 8월에 감소된 반면에 수영천은 크게 유실되고 서서히 증가되는 양상을 보여 하천 간에 차이가 뚜렷하였다. 생체량의 변동과 풍부도 동태는 매우 유사한 양상을 보여주었다. CCA분석결과, 수온과 기온은 복족류와 상관성이 높았으며 생물분류군의 환경에 대한 반응은 두 하천에 따라 다르게 나타났다.

• 한국농공학회지
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• 제21권3호
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• pp.83-91
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• 1979

This study was conducted in order to find out the performance of rice transplanters in accordance with the change of the trans-planting days after pudding and the water depth flooding the paddy field at the time of transplanting : and thus to select the optimum paddy field preparation procedures for an efficient utilization of rice transplanters. The performance factors of the two different types of rice transplanters were measured during the first 6 consecutive days after puddling and with 3 different levels of water depth flooding the paddy fields. The results of this study were analysed and summarized as follows : 1. Wheel sinkage decreased very rapidly from 0 to 2 days after puddling and slowly from 3 to 5 days after puddling. 2. The depth of the test cone penetration decreased rapidly during the first few days after puddling. It was 17.8cm just after puddling, and decreased to 13.4cm one day after puddling. After 2 days, the rate of decrease was dampened, and after 5 days it kept constant value of 9.2cm. 3. Two days after puddling, the hill interval was 15.8cm (98.75% of the preset value) for broadcasted seedling rice transplanter with 3cm flooding depth : This value was the closest to the pre-adjusted value of 16cm. The general performance of broadcasted-seedling type rice transplanter was better than that of strip-seedling type rice transplanter. 4. Usually the working performance of a rice transplanter is evaluated with uniformity and adjustability of the hill intervals. The hill interval was the most uniform and closest to the pre-set value of 16cm when planted two days after puddling with 3cm of water depth. When it was inavoidable to plant 4 days after puddling with stripseedling type rice transplanter, it is advisable to let the water flooded somewhat deeper. 5. The percentage of missing hills including floating and burried seedlings was the highest just after puddling and ie decreased substancially until 3 days after puddling and then it increased again. Hence, the optimal time transplanting is to be between 2 and 3 days after puddling. 6. Better postures of planted seedlings were found when planter 2 days after puddling than 3 days after puddling. Six cm of flooding water depth always gave the best results with respect to the postures of planted seedlings. Broadcasted-seedling rice transplanter, in general, showed better posture of planted seedlings than did strip-seedling type rice transplanter. 7. Judging from the above results, the optimal conditions will be 3cm of flooding depth and transplanting between 2 and 3 days after puddling.

• 한국수자원학회논문집
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• 제55권12호
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• pp.1091-1104
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• 2022

기후변화는 전 세계적으로 강우의 빈도와 강도를 증가 시킬 것으로 예측되며 급격한 도시화와 산업화로 인해 도시 지역의 내수 침수 피해로 양상이 바뀌고 있다. 이에 기후변화에 따른 영향평가는 도시계획에 매우 중요한 요소로 언급되고 있으며, 세계기상기구(WMO)는 기상 현상으로부터 발생할 수 있는 사회, 경제적 영향을 고려하는 영향예보의 필요성을 강조하고 있다. 특히 교통에 있어서 도시침수로 인한 교통 시스템의 성능 저하는 사회에 가장 해로운 요소이며 영향을 받는 주요 도로마다 시간당 £ 100k 정도인 것으로 추정하고 있다. 그러나 국내의 경우 현재 기상재해의 발생에 대한 정확한 예보 및 특보를 제공해도 그 영향을 제대로 전달하지 못하고 있다. 따라서 본 연구에서는 도시홍수의 침수심을 제시하고 차량에 영향을 미칠 수 있는 피해에 대처하기 위해 각 지역의 고해상도 분석 및 수문학적 요인을 반영하고, 강우로 인한 홍수 정도와 차량 운행에 미치는 영향 정도를 조사할 필요가 있다고 판단하였다. 이에 강우-침수심-차량속도의 산정식을 간단한 선형회귀식이 아닌 다양한 머신러닝 기법을 이용하여 제시하고자 한다. 또한 또한 기후변화 시나리오를 강우-침수심-차량속도 산정식에 적용하여 집중호우 시 도시하천의 침수를 예측하고 미래 기후변화의 영향을 고려한 도로 침수로 인해 발생할 수 있는 교통 네트워크의 장애를 평가하며, 도시 교통흐름 계획에 이용하는 기술을 개발하고자 한다.

• 한국지형학회지
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• 제28권4호
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• pp.15-30
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• 2021

This study analyzed the changes in land-cover and sedimentary environment before and after flooding through drone images and sediment analysis for the Seomjin River Chimsil Wetland. The results showed that the area of some land-covers such as sand bar, grass, and trees were continuously changed. The acidity level of the sediments in the Seomjin River Chimsil Wetland was weakened gradually by flooding and EC was also decreased. The levels of organic matter, effective phosphoric acid, and CEC, however, were fluctuating depending on branches, which seems to be the result of landization as new sedimentary environment was developed and vegetation was settled after the flood. Average mean size of river sediments was found to be fine sand, and it exhibited various particle size characteristics from granule to medium silt depending on the location. As the sedimentary environment changed due to the effects of floods and typhoons, the particles were granulated or grain refined depending on the position. In the Seomjin River Chimsil Wetland, there were factors that could interfere with geomorphic development and sedimentary environment, contamination sources in and around the wetland, and natural threat factors. Therefore, in this study, a conservation and management plan was proposed to remove these threat factors and to preserve the scarcity, naturalness, and dynamics of Seomjin River Chimsil Wetland.