• Proceedings of the Korean Reliability Society Conference
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• 2000.04a
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• pp.239-246
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• 2000

This paper presents a new dynamic approach for assessing feasibility associated with the implementation of accident management strategies by the operators. This approach includes the combined use of both the concept of reliability physics and a dynamic event tree generation scheme. The reliability physics is based on the concept of a comparison between two competing variables, i.e., the requirement and the achievement parameter, while the dynamic event tree generation scheme on the continuous generation of the possible event sequences at every branch point up to the desired solution. This approach is applied to a cavity flooding strategy in a reference plant, which is to supply water into the reactor cavity using emergency fire systems in the station blackout sequence. The MAAP code and Latin Hypercube sampling technique are used to determine the uncertainty of the requirement parameter. It has been demonstrated that this combined methodology may contribute to assessing the success likelihood of the operator actions required during accidents and therefore to developing the accident management procedures.

• Nuclear Engineering and Technology
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• v.27 no.3
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• pp.292-300
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• 1995

This paper present a new dynamic HRA (Human Reliability Analysis) method and its application for Quantifying the human error probabilities in implementing an accident management action. For comparisons of current HRA methods with the new method, the characteristics of THERP, HCR, and SLIM-MAUD, which are most frequently used methods in PSAs, are discussed. The action associated with the implementation of the cavity flooding during a station blackout sequence is considered for its application. This method is based on the concepts of the quantified correlation between the performance requirement and performance achievement. The MAAP 3.0B code and Latin Hypercube sampling technique are used to determine the uncertainty of the performance achievement parameter. Meanwhile, the value of the performance requirement parameter is obtained from interviews. Based on these stochastic distributions obtained, human error probabilities are calculated with respect to the various means and variances of the timings. It is shown that this method is very flexible in that it can be applied to any kind of the operator actions, including the actions associated with the implementation of accident management strategies.

• Journal of Korea Water Resources Association
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• v.35 no.1
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• pp.65-75
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• 2002

The objectives of this study are to analyse model-based soil moisture variations depending on model parameters m and $T_0$ and to evaluate the model performance for the simulation of soil moisture variations by the comparison of observed groundwater levels and model-driven soil moisture amounts and observed and simulated river discharges at the basin outlet. The selected study area is the Pyungchang IHP river basin with outlet at Sanganmi station and the summer flooding events during '94-'98 are used for the analysis. As a result, soil moisture holding capacity is increased according to increase the parameter m that represents effective groundwater depth. This phenomenon is especially dominant when higher m and $T_0$ values are used. The qualitative comparison of computed base flow and observed groundwater level shows that the base flow peaks are reasonably simulated and the decreasing limbs of hydrograph are mainly caused by base flows. It is concluded that TOPMODEL can be used effectively for simulating basin-averaged soil moisture variations in addition to river flow generations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.3A
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• pp.311-320
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• 2006

This paper proposes DDTM for USN having end-point mobility. The existing network protocols did not consider target's and sink's mobility. So it requires flooding and path update whenever targets or sinks move. This can lead to drain battery of sensors excessively and decrease lifetime of USN. DDTM is the protocol based on TTDD considering sink's mobility. TTDD provides sink's mobility efficiently by using the grid structure, but it requires the high energy because of reconstructing the grid structure whenever targets move. In this way, the proposed protocol can decrease a consumption of energy, since it reuses the existing grid structure of TTDD, if the target moves in local cell. We compare DDTM with TTDD under the total message and the energy consumption by using a discrete analytical model for cost analysis. Analytical results demonstrated that our proposed protocol can provide the higher efficiency on target's mobility.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• no.1
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• pp.59-66
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• 2001

The tremendous growth of population and physical development in the largest urban agglomeration in Indonesia -the Jakarta Metropolitan Region, also known as Jabotabek (Jakarta, Bogor, Tanggerang, Bekasi)- has created many environmental problems, such as land use conversion, increasing urban temperature, water and air pollution, intrusion of seawater, and flooding. These problems have become more serious as the urban green space (trees, shrubs, and groundcovers) has decreased rapidly with the urbanization process. Urban green space directly benefits the urban environment through ameliorating air pollution, controlling temperature, contributing to the balance of the hydrological system, and providing space for recreation and relaxation. Because there is little hard data to support the claim of decreasing greenery in Jabotabek, it is necessary to measure the amount of urban green space. The paper describes the spatial analysis of urban green space within Jabotabek through the use of a geographical information system (GIS). We used GIS and remote sensing to determine land cover change and predicted greenery percentage. Interpretation of Landsat data for 1972, 1983, 1990, and 1997 showed that Jabotabek has experiences rapid development and associated depletion of green open space. The proportion of green open space fell by 23% from 1972 to 1997. We found a low percentage of urban green space in the center of Jakarta but a high percentage in fringe area. The amount of greenery is predicted by the Ratio Vegetation Index (RVI) model: predicted greenery (%) = [146.04] RVI - 134.96. We consider that our result will be useful for landscape planning to improve the environment of Jabotabek.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.414-414
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• 2012

하천에 산사태, 하천 주변 개발, 제방 및 댐 붕괴 등으로 인하여 다량의 토사가 돌발적으로 유입될 경우 유입된 토사가 하천의 거동에 미치는 영향은 막대하다. 또한 하도 내에 설치되어 있는 교량, 보와 같은 수공 구조물로 인하여 단면형태가 갑작스럽게 변화하는 경우나, 구조물로 인하여 토사가 퇴적되는 경우 하천의 수위 변화를 크게 유발하여 하천 범람과 제방 침식 등을 발생시키며 하천의 안전에 큰 위험 요인으로 작용하게 된다. 현재 다량의 토사가 하천에 돌발적으로 유입되는 위험으로부터 안전하게 보호하기 위해서 토사 유입 방지 대책에 대하여 많은 연구와 사업이 실시되고 있지만 이러한 치수대책이 완전하다고 하기에는 다소 어려운 상황이다. 따라서 홍수 조절 및 방재를 위한 수방대책 수립 및 수자원의 집중적인 관리가 무엇보다 절실히 요구되며, 이와 같은 토사에 의한 방재대책 수립을 위해서 수리학적 특성을 정확히 파악할 필요가 있다. 본 연구에서는 2011년 7월에 발생한 강우에 의하여 침수피해가 발생된 경기도 이천의 오천천을 대상으로 수치해석을 통한 침수 범람 원인을 분석하였으며, 하류부에 위치하고 있는 공장의 경우 내부가 1m이상 침수됨에 따라 흔적수위 및 현장 상황을 조사하였고, 당일 강우를 통한 홍수위를 산정하여 여러 가지 원인별 홍수 원인을 분석하였다. 2011년 7월에 발생된 강우는 복하천 하천정비기본계획에 제시되어 있는 설계빈도로 30년 빈도에 못 미치는 것으로 나타나 강우에 의한 영향보다는 외부 영향으로 판단되며, 상류로부터 순간적으로 유입된 토사의 과다 퇴적에 의한 수위 상승에 의하여 교량 및 보 등의 수공구조물과 연계된 통수 단면적의 부족 등의 영향으로 홍수 범람이 발생된 것으로 분석되었다. 홍수 범람에 의한 영향을 분석하기 위하여는 단순히 강우에 대한 영향을 고려하는 것 보다 하천의 전반적인 특성을 고려하여 정확한 원인 규명을 통한 대처방안이 수립되어야 하며, 지속적인 모니터링을 통하여 하천에 의한 피해를 최소화 할 필요가 있다.

• Journal of Korean Society on Water Environment
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• v.29 no.6
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• pp.754-761
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• 2013

Urban floods are usually caused by the lack of drainage capacity. Hence, sewer capacity expansion methodology by replacing small pipes with bigger ones is primarily applied as a flood control measure. However, this approach is often unreasonable because of the costs and time involved. Thus, the installation of underground rainwater storage tanks with the two advantages of flood control and water conservation is proposed. This study compared the effectiveness of flood control by both the sewer expansion methodology and rainwater storage tanks using the Storm Water Management Model. Three cases were simulated in this study. The first case analyzed flood reduction by the storm sewer expansion methodology. The simulation results indicate that the overflow volume from manholes was reduced by 49% with this methodology. The second case analyzed flood reduction by installation of rainwater storage tanks. The simulation results indicate that the overflow volume was reduced by 62%. However, these two cases could not prevent urban floods completely. Hence, the third case analyzed the joint application of the storm sewer expansion methodology and rainwater storage tanks. In this simulation, flooding did not occur. Consequently, the results of this study clearly show that underground rainwater storage tanks are more effective for flood control than capacity expansion of storm sewer. Furthermore, the joint application of these two flood control measures is more effective than their separate application.

• Parasites, Hosts and Diseases
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• v.42 no.3
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• pp.121-127
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• 2004

The aim of this study was to relate personal data, socio-cultural and environmental characteristics, and the presence of symptoms/signs with the frequencies of Giardia spp. and Blastocystis hominis among a rural population in Buenos Aires Province, Argentina. Of the surveyed population (350), 3.7% were infected with only Giardia spp. or 22.9% with B. hominis, and 2.3% were infected with both protozoa. The frequency of infection according to sex; 6.1% of males were infected and 1.6% of females by Giardia spp., 26.7% and 19.5% by B. hominis, and 2.4% and 2.2% by both parasites, respectively. Giardia spp. was detected in only three adults (over 14 years), but B. hominis was more frequent in adults than in children. The prevalences of these protozoa in this community are lower than those reported by other Argentinean studies, which is probably associated with the low density of the studied population ($5.95{\;}inhab/\textrm{km}^2$). Statistical analysis revealed that a male sex, flooding of the home, the use of a latrine, and an abdominal pain were correlated with the presence of these parasites, which indicate the importance of these factors in rural communities.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.6
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• pp.1214-1221
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• 2007

Ad-hoc network is soft wireless communication network that is consisted of mobile node and clusters without helping of infrastructure. We propose a new ad hoc multicast routing protocol for based on the ontology scheme called inference network. Ontology knowledge-based is one of the structure of context-aware. Proposed structure is consisted of context awareness parameters as like distance between each nodes. The proposed architecture performs two types of routing discovery. One is Flooding Discovery Routing(FDR) for comparing analysis step and Local Discovery Routing(LDR) to compose path of node forecast(preservation) step from node's state value. The inference network structure of proposed RODMRP(Resilient Ontology-based Dynamic Multicast Routing Protocol) adopts a tree structure to enhance an efficient packet in various environment between mobile node. We will have developed an algorithm that will desist multi-hierarchy Layered networks to simulate a desired system.

• Journal of The Geomorphological Association of Korea
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• v.24 no.3
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• pp.83-103
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• 2017

Sand deposit with shell units is exposed in Hasa-ri, Yeonggwang-gun, Jeonnam province. We investigated the characteristics of sand sediment topography in the Yeonggwang coastal area to collect evidence of the paleo-environmental change. We performed analysis on particle characteristics, chemical composition, and the age of deposition of sediments. The deposit comprise moderately well sorted medium and fine sand ($1.00{\sim}2.19{\varphi}$). Various sedimentary structures can be observed. Geochemical characteristics change by depth and the degree of variation with depth is small. The results obtained from OSL dating show that sand layers below shell units are deposited 0.32-0.43 ka. As the elevation of the shell unit far mean high water levels or highest high water level, the extensive shell layers could only have been deposited during storm surge conditions. Aeolian processes are discounted due to the size of clasts and the location at which they occur. Results of age dating of the surrounding deposits indicate shell deposits formed after around 300 years age. There is a distinct difference between sedimentary layers including dark brown-black layer. The sedimentary characters such as particle size and geochemistry show difference with depth. It is presumed that depositional environmental in Hasa-ri has changed several times before. This study is expected to contribute to finding an evidence about occurrence of storm surges.