• Journal of Korean Society of Disaster and Security
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• v.15 no.4
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• pp.87-98
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• 2022

In recent years, frequent localized heavy rainfalls, which have a lot of rainfall in a short period of time, have been increasingly causing flooding damages. To prevent damage caused by localized heavy rainfalls, Hydrological Quantitative Precipitation Forecast (HQPF) was developed using the Local ENsemble prediction System (LENS) provided by the Korea Meteorological Administration (KMA) and Machine Learning and Probability Matching (PM) techniques using Digital forecast data. HQPF is produced as information on the impact of heavy rainfall to prepare for flooding damage caused by localized heavy rainfalls, but there is a tendency to overestimate the low rainfall intensity. In this study, we improved HQPF by expanding the period of machine learning data, analyzing ensemble techniques, and changing the process of Probability Matching (PM) techniques to improve predictive accuracy and over-predictive propensity of HQPF. In order to evaluate the predictive performance of the improved HQPF, we performed the predictive performance verification on heavy rainfall cases caused by the Changma front from August 27, 2021 to September 3, 2021. We found that the improved HQPF showed a significantly improved prediction accuracy for rainfall below 10 mm, as well as the over-prediction tendency, such as predicting the likelihood of occurrence and rainfall area similar to observation.

• Journal of agriculture & life science
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• v.51 no.1
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• pp.35-43
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• 2017

This research was carried out to excessive water tolerance test among corn accessions collected from India to breed corn cultivars targeting India market. The corn accessions were 20 Inbred lines and cultivars from India as well as Korean cultivars Gwangpyungok and Chaloksusu. Excessive water tolerance test was done in the green house by immerging the pots containing corn seedlings for two weeks. Then, the plant heights were measured to compare the control plants that were not grown in the immerging state. The results showed that seven accessions of high tolerance in flooding; H2(92.9%), H18(88.8%), CN114A(98.1%), CN351A(94.3%), Super900M(95.3%), P3394(98.8%), 31N27(96.7%) in which the percent is comparison to the control plants. Whereas nine accessions showed high damage by immerging; H1(78.9%), H8(73.4%), H10(77.1%), H19(79.0%), H26(74.1%), H31(75.7%), H34(77.5%), H36(77.4%), H40(74.6%). However, the reduction on the contents of chlorophyll a, chlorophyll b, carotenoids in leaf revealed contrast results to the flooding tolerance. Particularly, H36($7.249{\mu}g{\cdot}mg^{-1}$) and H40($7.642{\mu}g{\cdot}mg^{-1}$) showed rapid reduction in the chlorophyll a content during the flooding treatment. Whereas two Indian commercial varieties 37N27($0.630{\mu}g{\cdot}mg^{-1}$) and P3394($1.208{\mu}g{\cdot}mg^{-1}$) showed slight reduction. The reduction of chlorophyll a and carotenoid contents was positively correlated during the excessive water stress.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.11a
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• pp.370-373
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• 2007

지하구내에 물이 유입되기 시작하면 미리 설치되어 있는 펌프를 동작시켜서 배수를 해야한다. 이 경우 지하구내로 유입되는 물의 경로로 구분한 내수와 외수의 양을 알 수 있다면 위험도의 평가에 있어서 좋지만 유입량을 정확히 알 수 없으므로 시계열 분석으로 미래의 값을 예측하는 방법을 제시하고자 한다. 시계열 분석으로 예측한 값을 토대로 퍼지 이론을 이용한 지하구내 침수 상황 통제 시스템을 구현하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.147-147
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• 2009

Every year respect a countermeasure establishment the electric leakage detection system and electric leakage investigation work are becoming enforcement line plentifully in about the electric leakage accident which is increasing, measuring in compliance with a most ground connection voltage and an image electric current mainly is become accomplished, inputs a pulsation group signal in the line and detects a signal change between the line a method which there is. In order to investigate the quality in compliance with an electric leakage electric current from the electric leakage area after conferring the electric leakage environment in compliance with a flooding when the electric leakage electric current exists in the surface, it investigated the electric leakage electric current quality from the electric current distribution and flooded districts from the present paper.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.447-452
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• 2001

Quenching phenomena of hemispherical downward facing convex surfaces with narrow gaps have been investigated experimentally. Experiments employed test sections having 1 and 2 mm in gap thickness and 1 atm in system pressure. From interpretations of the temperature and the heat flux history, it was found that the flooding inside the gap was restricted by CCFL phenomena and quenching process was propagated from lower to upper region of the internal copper shell. The ratio of the maximum heat fluxes at 1 mm to 2mm in gap thickness was the almost same that obtained by steady state experiments. The quenching scenario of the hemispherical downward facing surface with narrow gap has been suggested.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.399-402
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• 2007

This project is the 1st. stage for the foreshore reclamation at Jang-Hang area and its scope is to construct a seawall as outer facilities, road adjacent to the seawall and drainage gate. for the safe protections of the facilities at the reclaimed land hereafter, we adopted the mild slope rubble mound type for the seawall structure which was excellent in interrupting the wave overtopping, as a result of numerical & hydraulic model test about alternative 4 sections. For the flooding prevention of the reclaimed land, we planned the drainage system that could make the flood water level lower than the reclaimed land level. Also, we planned the eco-friendly waterfront area with 8 nature themes through the whole seawall sections.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.367-370
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• 2007

In recent, the utilization of underground in urban area is increased as subway, store, and others but we have done a few studies for the inundation of underground due to flooding. So, we investigate the examples of underground inundation and the causes of inundation for flood events. And the relationship between flood characteristics and underground inundation is analyzed through the frequency of rainfall which is made by annual multi maximum series. As a result, most of underground is inundated by high frequency of rainfall. And there are some cases that the underground is inundated by low frequency of rainfall because of poor drainage system and characteristics of location.

• Journal of Environmental Science International
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• v.14 no.11
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• pp.995-1004
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• 2005

As a research establish reservoir safety operation for small dam systems. This study presents hydrologic analysis conducted in the Duckdong and Bomun dam watershed based on various rainfall data and increase inflow. Especially the Duckdong dam without flood control feature are widely exposed to the risk of flooding, thus it is constructed emergency gate at present. In this study reservoir routing program was simulation for basin runoff estimating using HEC-HMS model, the model simulation the reservoir condition of emergency Sate with and without. At the reservoir analysis results is the Duckdong dam average storage decrease $20\%$ with emergency gate than without emergency gate. Also, the Bomun dam is not affected by the Duckdong flood control augmentation.

• ETRI Journal
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• v.30 no.2
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• pp.282-289
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• 2008

We propose a new mini-slot transmission scheme for a passive optical network (PON) in which each customer can be switched either to access mode or to internetworking mode dynamically. In this paper, we present the system implementation (called LAN-PON) as well as the performance of the proposed transmission scheme to illustrate its feasibility and benefits. A mini-slot scheme can rapidly reduce the queuing delay, which increases due to the flooding of the deflected packets in a deflection scheme. We evaluate the impact of mode switching time on the bandwidth gain (throughput) and delay of local area network (LAN) traffic in the LAN-PON with a mini-slot scheme. We also analyze a theoretical delay model of the proposed scheme. The simulation results demonstrate that switching time has an impact on LAN performance, and the average packet delay of the proposed scheme is significantly improved compared to that of the deflection scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.4
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• pp.895-909
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• 2013

Distributed Denial-of-Service (DDoS) attacks towards name servers of the Domain Name System (DNS) have threaten to disrupt this critical service. This paper studies the vulnerability of the cache server to the flooding DNS query traffic. As the resolution service provided by cache server, the incoming DNS requests, even the massive attacking traffic, are maintained in the waiting queue. The sojourn of requests lasts until the corresponding responses are returned from the authoritative server or time out. The victim cache server is thus overloaded by the pounding traffic and thereafter goes down. The impact of such attacks is analyzed via the model of queuing process in both cache server and authoritative server. Some specific limits hold for this practical dual queuing process, such as the limited sojourn time in the queue of cache server and the independence of the two queuing processes. The analytical results are presented to evaluate the impact of DDoS attacks on cache server. Finally, numerical results are provided for further analysis.