• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.4
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• pp.491-498
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• 2003

The advanced computer network technology enables connectivity of computers through an open network environment. There has been growing numbers of security threat to the networks. Therefore, it requires intrusion detection and prevention technologies. In this paper, we propose a network based intrusion detection model using FCM(Fuzzy Cognitive Maps) that can detect intrusion by the DoS attack detection method adopting the packet analyses. A DoS attack appears in the form of the Probe and Syn Flooding attack which is a typical example. The SPuF(Syn flooding Preventer using Fussy cognitive maps) model captures and analyzes the packet informations to detect Syn flooding attack. Using the result of analysis of decision module, which utilized FCM, the decision module measures the degree of danger of the DoS and trains the response module to deal with attacks. For the performance comparison, the "KDD′99 Competition Data Set" made by MIT Lincoln Labs was used. The result of simulating the "KDD′99 Competition Data Set" in the SPuF model shows that the probe detection rates were over 97 percentages.

• Geosystem Engineering
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• v.21 no.6
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• pp.335-343
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• 2018

Alkali-surfactant polymer flooding has become an important technique to improve oil recovery following the development of oil fields while the function of emulsification in enhanced oil recovery is rarely considered in the existing mathematical model for numerical simulation. In this paper, the mechanism of improving the recovery of the emulsification was analyzed in ASP flooding, and a relatively perfect mathematical model with deep filtration-theory was established, in which oil-water volume equation, saturation equation, viscosity equation, and permeability reduction equation are included. The new model is used to simulate the actual block of an oil field; the simulated results of the new model and an old model without considering the emulsification are compared with the actual well history. It is found that new model which is easy to be realized in numerical simulation has a high precision fitting, and the effect of adding oil and decreasing water is obvious. The sensitivity of emulsification was analyzed, and the results show that the water reducing funnel becomes wider and the rate of water cut decreases rapidly with the increase of emulsifying capacity, and then the rate of recovery slows down. The effect of increasing oil and decreasing water is better, and the degree of recovery increases. The emulsification of the ASP flooding is maintained at a moderate level, which corresponds to ${\Phi}=0.2$ in the new model, and the emulsification is applied to realize the general mathematical quantitative description, so as to better guide the oilfield development.

• Proceedings of the KIEE Conference
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• 2008.09a
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• pp.305-307
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• 2008

Inundation of substation and ground power equipment breaks out every summer season in low-lying downtown and low-tying shore by heavy rain, typhoon and tidal wave. In case inundation excluding the exchanging cost of equipment, it occurs a great economic and social loss owing to recovery time and events of electric shock occur by inundation electrical equipment (Pad-mounted Transformer and Switch). So we research the flooding prevention countermeasures of electrical facility and Transformer Vault on Foreign. We conform the site facility and related regulation for flooding prevention on Foreign.

• Journal of the military operations research society of Korea
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• v.18 no.2
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• pp.126-139
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• 1992

In this paper, the computational problems of packet transmission probability (PTP) in a computer communication network (CCN) under flooding routing are investigated. To avoid a congestion under this routing, two control methods are considerd, i. e., copy storage control and hop count control. Problems of PTP under flooding routings with these two control methods are respectively shown to be equivalent to those of source-to-terminal reliability(STR) with an exception for a case of hop count control where the hop count is less than the length of the longest path. For this exceptional case, an efficient computational algorithm for PTP is developed. This algorithm is proposed as an efficient tool for the determination of hop count which satisfies a given reliability constraint. A numerical example illustrates a proposed algorithm.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.725-728
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• 2011

멀티홉 네트워크에서 플러딩(Flooding) 기법은 토폴로지 내의 모든 노드에게 패킷을 전달하는 것이다. 대표적인 플러딩 기법인 Blind 플러딩은 패킷을 받은 모든 노드가 플러딩을 하기 때문에, 무선 네트워크의 전체적인 성능이 감소한다. 기존 연구에서는 성능 향상을 위해 중복 수신되는 패킷을 줄이는 데에만 초점이 맞춰져 있다. 하지만 실제 무선 네트워크 환경에서는 간섭에 따른 패킷 손실이 발생하고, 플러딩은 Broadcast 로 전송하기 때문에 재전송하여 손실 패킷을 복구할 수 없다. 본 논문에서는 Blind, Self-Pruning, Dominant-pruning 플러딩 기법에 재전송이 필요 없는 오류정정 기법(FEC)를 적용하여, 추가적인 잉여 데이터에 따른 전체 전송 패킷의 수와 플러딩 기법의 신뢰성을 분석 하였다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.129-130
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• 2023

This study proposes rainwater infiltration retention blocks as a solution to the flooding problems caused by recent climate change and developed a flood prediction simulation program to select the optimal site for installing rainwater infiltration retention blocks that can minimize damage from floods. By applying the existing 2D flood analysis model G2D and adding a reservoir function, the volume of water before and after installation can be determined through simulation results.

• Journal of the Korean GEO-environmental Society
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• v.17 no.9
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• pp.21-28
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• 2016

The purpose of this study is to compare the three areas that each estimated by using three different river topographic maps. For construction of river topographic maps, the data used in this study are ASTER, SRTM and a 1:5,000 scale digital map data sets in 14 streams of the Cheongdo-gun and Uiseong-gun. HEC-GeoRAS, RAS Mapper, and RiverCAD model are applied for the flooding area analysis using observed data and design rainfalls. The result of analysis is to compare observed flooding area based on the flood plain maps with estimated inundation area by hydraulic models and constructed river topographic maps. The results of this study are as follows; Flooding area by HEC-GeoRAS model is similar to the inundation area of flood plain map and appears in order of RAS Mapper, and RiverCAD model in all watersheds. Flood inundation area by SRTM DEM is similar to the result of 1:5,000 scale digital map in all watersheds and all analysis models. The SRTM DEM shows the most similarity to the digital map than ASTER DEM in all of the watershed scale and analysis models. HEC-GeoRAS and RiverCAD model are efficient models for flood inundation analysis in small watershed and HEC-GeoRAS and Ras Mapper model are efficient in medium to large watershed.

• The Journal of the Korea Contents Association
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• v.4 no.4
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• pp.33-43
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• 2004

In this paper, a traffic trend analysis based SNMP algorithm is proposed for improving the problem of existing traffic analysis using SNMP. The existing traffic analysis method has a vulnerability that is taken much time In analyzing by using a threshold and not detected a harmful traffic at the point of transition. The method that is proposed in this paper can solve the problems that the existing method had, simultaneously using traffic trend analysis of the day, traffic trend analysis happening in each protocol and MIB object analysis responding to attacks instead of using the threshold. The algorithm proposed in this paper will analyze harmful traffic more quickly and more precisely; hence it can reduce the damage made by traffic flooding attacks. When traffic happens, it can detect the abnormality through the three analysis methods previously mentioned. After that, if abnormal traffic overlaps in at least two of the three methods, we can consider it as harmful traffic. The proposed algorithm will analyze harmful traffic more quickly and more precisely; hence it can reduce the damage made by traffic flooding attacks.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.5
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• pp.549-560
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• 2010

Recently, heavy rainfalls due to the climate change in Korea have caused inundation problems in urban sewer networks. In july 2006, a flooding accident at Misari motorboat racing stadium near the Han river occurred due to the effect of record-breaking outflow discharge from Paldang-dam. The purpose of this study was to simulate and analyze the flooding accident at Misari stadium by MOUSE model. The results of simulation analysis indicated that the total flood volume was $1,313,450m^3$. The effect of back water was 85.9% of the total volume which was caused by the manhole accident, and the effect of accumulated runoff was 14.1% of total volume which was caused by non-return valve shutdown. The simulation results of this MOUSE modeling that was linked to the boundary condition of the dynamic flows in the river by DWOPER model showed the potential of successful inundation analysis for sewer networks.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.1 s.145
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• pp.1-14
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• 2006

To improve maritime safety, it is very important not only to make safer design and operation but also to do proper response in case of maritime casualty. The large-scaled casualties will be caused by loss of structural strength and stability due to the progressive flooding and enlargement of damage by the effect of waves and wind. To prevent foundering and structural failure, the prediction of ship motion behavior of damaged ship in wave is necessary. This paper describes the motion behavior of damaged ship in waves through theoretical and experimental studies. A time domain theoretical model of damaged ship motions and accidental flooding, which can be applied to any type of ship or arrangement and considers the effects of flooding of compartments, has been developed. The model tests have been carried out in regular and irregular waves with different wave heights and directions in ship motion basin. Those were performed for three different damaged conditions such as engine room bottom damage, side shell damage and bow visor damage of a Ro-Ro ship. Comparison of theoretical and experimental results was performed.