• 대한교통학회지
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• 제27권4호
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• pp.167-173
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• 2009

교통사고는 인간의 생명과 직결되는 문제이므로, 교통사고 예방 및 심각도 감소를 위한 연구는 매우 중요하다고 할 수 있다. 따라서 본 연구에서는 교통사고 심각도에 영향을 줄 수 있는 다양한 영향요소들을 고려하여 교통사고로 인한 피해를 최소화할 수 있는 대응책을 수립하고자 하였다. 본 연구에서는 2004~2006년 동안 서해안 고속도로에서 발생한 174개의 구간별 사고자료를 이용하여 사고 심각도 예측모형을 만들었다. 이렇게 분석된 모형을 이용하여 사고심각도에 영향을 미치는 주요요인을 찾고 이를 이용하여 교통사고로 인한 피해를 줄일 수 있는 다양한 방법들을 고려해 보았다. 분석결과 과속으로 인한 사고, 차량결함, 차대차 사고, 차대사람 사고, 교통량, 곡선반경 및 종단경사 변동계수에 의해 사고심각도가 정의되는 것을 알 수 있다. 이와 같은 사고심각도와 밀접한 관련이 있는 독립변수들을 대상으로 구간에 따른 각 영향의 정도를 그래프를 나타내 보았으며, 그 결과 심각한 사고를 유발하는 특정원인이 몇 가지 존재하며 이러한 특정원인 및 사고유형은 서해안 고속도로의 특정구간에서 주로 발생한다는 것을 알 수 있다. 이러한 결과들은 서해안 고속도로의 특정 구간에 속도제한 단속 카메라, 차내/외 경고정보제공등과 같은 선택적 교통정보 및 교통시설을 제공함으로써 사고를 예방하는 방법에 활용될 수 있을 것이다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2011년도 학술발표회
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• pp.17-17
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• 2011

As a method of countermeasure to bed degradation and armoring phenomena of bed material in the downstream area of dam reservoirs, sediment augmentation (replenished sediment) has been carried out in many Japanese rivers. In general, bed of the replenished sediment site is composed of rocks, because the site is located in the downstream area of the dams and sediment supply is very small. Bed deformation process has been researched by many researchers. As a method of countermeasure to bed degradation and armoring phenomena of bed material in the downstream area of dam reservoirs, sediment augmentation (replenished sediment) has been carried out in many Japanese rivers. In general, bed of the replenished sediment site is composed of rocks, because the site is located in the downstream area of the dams and sediment supply is very small. Bed deformation process has been researched by many researchers. However, most of them can treat movable bed only and cannot be applied to the bed deformation process of sediment on rocks. If the friction angle between the sediment and the bed surface is assumed to be the same as the friction angle between the sediment and the sediment, sediment transport rate must be smaller without sediment deposition layer on the rocks. As a result, the reproduced bed geometry is affected very well. In this study, non-equilibrium transport process of non-cohesive sediment on rigid bed is introduced into the horizontal two dimensional bed deformation model and the model is applied to the erosion process of replenished sediment on rock in the Nakagawa, Japan. Here, the Japanese largest scale sediment augmentation has been performed in the Nakagawa. The results show that the amounts of the eroded sediment and the remained sediment reproduced by the developed numerical model are $56300m^3$ and $26800m^3$, respectively. On the other hand, the amounts of the eroded sediment and the remained sediment measured in the field after the floods are $56600m^3$ and $26500m^3$, respectively. The difference between the model and field data is very small. Furthermore, the bed geometry of the replenished sediment after the floods reproduced by the developed model has a good agreement with the measured bed geometry after the floods. These results indicate that the developed model is able to simulate the erosion process of replenished sediment on rocks very well. Furthermore, the erosion speed of the replenished sediment during the decreasing process of the water discharge is faster than that during the increasing process of the water discharge. The replenished sediment is eroded well, when the top of the replenished sediment is covered by the water. In general, water surface level is kept to be high during the decreasing process of the discharge during floods, because water surface level at the downstream end is high. Hence, it is considered that the high water surface level during the decreasing process of the water discharge affects on the fast erosion of the replenished sediment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권10호
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• pp.2731-2749
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• 2012

Sybil attack has been proved effective in mitigating the P2P botnet, but the impacts of some important parameters were not studied, and no model to estimate the effectiveness was proposed. In this paper, taking Kademlia-based botnets as the example, the model which has the upper and lower bound to estimate the mitigating performance of the Sybil attack is proposed. Through simulation, how three important factors affect the performance of the Sybil attack is analyzed, which is proved consistent with the model. The simulation results not only confirm that for P2P botnets in large scale, the Sybil attack is an effective countermeasure, but also imply that the model can give suggestions for the deployment of Sybil nodes to get the ideal performance in mitigating the P2P botnet.

• 자연, 터널 그리고 지하공간
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• 제1권2호
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• pp.59-71
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• 1999

Recently, many deformations in tunnel such as crack and leakage were occulted. Specially, the defects of tunnel lining have been a serious problem in safety and stability many repair works for maintenance in tunnel have been carried out. Therefore, it is necessary to estimate the structural cracking for countermeasure in deformed tunnel and to investigate on the characteristics of lining system and the soundness of tunnel. In this study model tests for tunnel lining were carried out using test apparatus and centrifuge, In the direct loading test, the prototype was Kyungbu high-speed railway tunnel and the scale is 1/10, and lining models were made of concrete. Test conditions included load conditions such as direction, shape and type, lining conditions such as single and double lining, thickness, and reinforcement. In centrifuge model test, the prototype was Seoul subway tunnel and the scale is 1/100, and lining models were made of aluminum and hydrostone. Test conditions included tunnel defects such as thickness shortage. behind cavity and longitudinal cracks, reinforcement methods such as epoxy, grouting and carbon sheet. From these model tests , the characteristics of deformation and failure for tunnel lining were estimated, and the structural behaviors of deformed lining and the effects of repair and reinforcement for tunnel lining were researched.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.112-119
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• 2000

the shaking table tests for 5 different model sections are performed to investigate the behaviors of quay walls during earthquakes and to evaluate the seismic performance of quay walls with countermeasures. 5 different model sections describe the cases of dense soil and loose soil in the foundation repectively the case to which gravel backfill was applied and the cases to which light material replacement method and sand compction pile method was applied repectively for sesmic countermeasure methods. Pore water pressures accelerations and deformations in quay walls and grounds are analyzed. As a result the softening of foundation and backfill soils have much influence on the behaviors of quay walls. Also light material replacement method and sand compaction pile method are effective in improving the seismic performance of quay walls.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 추계학술발표회논문집(1)
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• pp.409-414
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• 1996

A model to estimate economic consequence of severe accident provides some measure of the impact on the accident and enables to know the different effects of the accident described as same terms of cost and combined as necessary. Techniques to assess the consequences of accidents in terms of cost have many applications, for instance in examining countermeasure options, as part of either emergency planning or decision making after an accident. In this study, a model to estimate the accident economic consequence is developed appropriate to our country focused on PWR accident costs from a societal viewpoint. Societal costs are estimated by accounting for losses that directly affect the plant licensee, the public, the nuclear industry, or the electric utility industry after PWR accident.

• 환경위생공학
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• 제14권4호
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• pp.29-34
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• 1999

1.The domestic waste generated in Iksan city was 177 tons a day last year. 27 tons of that were recycled daily. Due to increased awareness the recycling rate also increased. 2. It is preferred to get continuous publicity and to enforce the program steadily to activate exchange centers and places like a flea market for reusable things, which will lead to increase the life-span of the current designated landfill site. 3. Because burying food waste in underground will be prohibited from year 2005, the reutilization of food waste by feeding domestic animals like ducks and making artificial fertilizer are preferred. 4. The case of Iksan city is expected to be a model to other cities by establishing a display room to accommodate its detail work demonstration, displaying modeled utilization items and exchange center, incinerator, duck ranch, lawn ground, etc. for making a city as an environmental preservation city model.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.216-221
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• 2000

This paper describes the analysis results on the PT ferroresonance at 154 kV GIS (gas Insulated substation by EMTP(Electro- magnetic Transient Program). We had simulated the PT ferroresonance between a potential transformer(PT) and an open circuit breaker's grading capacitance. The ferroresonance leads to very large power frequency overvoltages on PT bus and subsequent insulation failure. The large power can be supplied to the PT by the high voltage on the opened circuit due to the grading capacitance and equivalent capacitance of the buses during the ferroresonance. The damping circuit connected on the secondary winding were considered in the model. The actual countermeasure include a saturable inductor and a resistor series-mounted, but the 2 ohms of damping resistance was used in the computationl model.

• 한국환경과학회지
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• 제12권1호
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• pp.69-76
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• 2003

When houses or buildings are adjacent to roads, with no effective prevention of road traffic noise, neighbors are exposed to it. It is important to understand the properties of sound propagation before taking a countermeasure against road traffic noise. It is easy to estimate the properties of sound propagation without obstacles, but very difficult and complex to estimate them with ones. The purpose of this study is to present a useful tool that can estimate the properties of sound propagation. In the beginning of this study, we investigated the attenuation of road traffic noise with two pillar buildings, and presented practical approximate calculation method, and verified that through scale model. The outcomes from this study are as follows : (1) Over second reflection sound waves can be ignored. (2) Diffraction sound waves that happen when reflection sound and first diffraction wave are projected at the wedge of other building can be ignored.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2076-2079
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• 1999

This paper describes the analysis results on the PT ferroresonance at 154 kV GIS (gas Insulated substation by EMTP (Electro-magnetic Transient Program). We had simulated the PT ferroresonance between a potential transformer(PT) and an open circuit breaker's grading capacitance. The ferroresonance leads to very large power frequency overvoltages on PT bus and subsequent insulation failure. The large power can be supplied to the PT by the high voltage on the opened circuit due to the grading capacitance and equivalent capacitance of the buses during the ferroresonance. The damping circuit connected on the secondary winding were considered in the model. The actual countermeasure include a saturable inductor and a resistor series-mounted, but the 2 ohms of damping resistance was used in the computational model.