• Journal of Environmental Science International
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• v.30 no.12
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• pp.1053-1065
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• 2021

In this study, the prediction technology of Hydrological Quantitative Precipitation Forecast (HQPF) was improved by optimizing the weather predictors used as input data for machine learning. Results comparison was conducted using bias and Root Mean Square Error (RMSE), which are predictive accuracy verification indicators, based on the heavy rain case on August 21, 2021. By comparing the rainfall simulated using the improved HQPF and the observed accumulated rainfall, it was revealed that all HQPFs (conventional HQPF and improved HQPF 1 and HQPF 2) showed a decrease in rainfall as the lead time increased for the entire grid region. Hence, the difference from the observed rainfall increased. In the accumulated rainfall evaluation due to the reduction of input factors, compared to the existing HQPF, improved HQPF 1 and 2 predicted a larger accumulated rainfall. Furthermore, HQPF 2 used the lowest number of input factors and simulated more accumulated rainfall than that projected by conventional HQPF and HQPF 1. By improving the performance of conventional machine learning despite using lesser variables, the preprocessing period and model execution time can be reduced, thereby contributing to model optimization. As an additional advanced method of HQPF 1 and 2 mentioned above, a simulated analysis of the Local ENsemble prediction System (LENS) ensemble member and low pressure, one of the observed meteorological factors, was analyzed. Based on the results of this study, if we select for the positively performing ensemble members based on the heavy rain characteristics of Korea or apply additional weights differently for each ensemble member, the prediction accuracy is expected to increase.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.154-154
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• 2020

최근 국지성 호우가 빈번하게 발생하고 있고, 이로 인해 국내 도시지역 홍수피해 발생빈도와 피해규모가 증가하고 있다. 2010년, 2011년, 2018년에 서울에서는 홍수로 인한 침수피해가 크게 발생하여 많은 인명과 재산의 피해가 있었다. 이렇듯 도시지역은 타 지역에 비해 인구와 재산이 밀집되어 있어 홍수 취약성이 상대적으로 높은 지역이다. 국내에서는 홍수피해 저감을 위해 홍수예보를 발령하고 있다. 하지만 국내 홍수예보는 국가하천 및 지방하천의 주요 하천 구간에서만 실시되고 있어 이러한 하천에 접하지 않는 지역은 국가 홍수예보의 수혜를 받을 수 없다. 그렇기 때문에 각 지역에서는 홍수 대응을 위해 기상청의 호우특보 기준을 사용하고 있으며 이 기준은 전국적으로 동일하다는 특징이 있다. 하지만 각 도시지역은 과거 홍수피해에 따라 방재시설을 추가로 설치하거나 보수하고 있어 각 지역의 방재시설 현황 및 홍수에 대한 취약성 정도가 다른 상황이다. 그러므로 전국적으로 동일한 강우기준이 적용되어 발령되고 있는 호우 특보는 실제 각 도시지역의 방재현황이 고려되지 못한다는 문제가 있다. 이와 관련하여 과거 낙동강 지역을 대상으로 지역별 홍수위험도에 따른 홍수위험지수를 산정하고 검토한 연구가 수행된 바 있다. 본 연구에서는 각 도시지역의 방재 현황을 고려하여 강우기준을 보정할 수 있는 가중치를 산정하는 방안에 대해 제시하였다. 이를 위해 서울 지역 25개 기초지자체를 대상으로 연구를 진행하였으며, 홍수 취약성을 평가하기 위한 세부인자는 노출도, 민감도, 적응도로 구분하였다. 각 세부인자 별 가중치를 산정하기 위해서는 엔트로피 방법을 적용하였고, 산정된 결과를 이용하여 각 지역 별 가중치를 산정하기 위해서는 유클리드 거리 산정법을 적용하였다. 그 결과 각 지역의 방재 특성을 고려한 가중치를 산정할 수 있었으며 향후에는 지역 별 방재특성이 고려된 강우기준을 제시 및 적용성을 검토할 계획이다.

• Journal of Korea Water Resources Association
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• v.52 no.4
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• pp.301-312
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• 2019

The importance of the dual drainage system model has increased as the urban flood damage has increased due to the increase of local storm due to climate change. The dual drainage model is a model for more accurately expressing the phenomena of surface flow and conduit flow. Surface runoff and pipe runoff are analyzed through the respective equations and parameters. And the results are expressed visually in various ways. Therefore, inundation analysis results of dual drainage model are used as important data for urban flood prevention plan. In this study, the applicability of the COBRA model, which can be interpreted by combining the dual drainage system with the natural watershed and the urban watershed, was investigated. And the results were compared with other dual drainage models (XP-SWMM, UFAM) to determine suitability of the results. For the same watershed, the XP-SWMM simulates the flooding characteristics of 3 types of dual drainage system model and the internal flooding characteristics due to the lack of capacity of the conduit. UFAM showed the lowest inundation analysis results compared with the other models according to characteristics of consideration of street inlet. COBRA showed the general result that the flooded area and the maximum flooding depth are proportional to the increase in rainfall. It is considered that the COBRA model is good in terms of the stability of the model considering the characteristics of the model to simulate the effective rainfall according to the soil conditions and the realistic appearance of the flooding due to the surface reservoir.

• Spatial Information Research
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• v.23 no.3
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• pp.35-44
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• 2015

Recently, the government aims to discover and provide services to citizens on the development strategy for activating the U-City. So, this study aims to offer a service discovery direction by analyzing the service issues and trends. The target is newspaper article about U-City Service from 2009 to 2014. Prepared 723 newspaper article for analysis. Next step is frequency analysis of keyword and used that result for Network analysis and measure of information. Network analysis can show result through "Degree Centrality", "Betweenness Centrality" and "Closeness Centrality". As a result, "Information", "IT", "Environment", "Technology", "Center" is higher than another. These 5 keywords are important factors for driving the U-City the past six years. Information measurement results, Already U-City were put an emphasis on building the infrastructure and able to identify a trend that provided the center of the public service. Those Service field are "Tour(2009)", "Crime prevention and Disaster Prevention(2010)", "Facility Management(2011)", "administration(2012)" and "Facility Management(2013, 2014)". Result of this study found implications what on citizen participation. So, services field on the existing infrastructure should be discovered and provided. Finally, this study can expected to be a reference in the local government planning for U-City.

• Korean Security Journal
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• no.60
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• pp.175-196
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• 2019

The purpose of this study is to examine the role of safety sheriffs and their necessity in order to improve the activation of safety sheriff's professionalism. Seven security sheriffs were finally selected to discuss their activities and discuss ways to improve their effectiveness. We conducted semi - structured interviews and conducted in - depth interviews with limited data and inadequate prior research. The results of this study are as follows. First, the government should get the help of citizens, citizens and residents. If the state wishes to reduce the number of safety accidents and bring positive results to the public, it should not rely solely on the utilization of institutions. Second, in order to be a safe sheriff with a positive response from the local residents, the activities of the sheriff's sheriff are not only aimed at preventing risks in the environmental domain and reducing the number of accidents, Publicity should be provided to the landlord, tenant, and residents to inform them that the activity is preventive of accident prevention. Third, under the current law, it is necessary to disclose public facilities such as roads, airports, and harbors to the private sector in order to make it possible to monitor school facilities and youth training facilities. Fourth, the safety sheriff is expected to put forward the expectations and positive results of prevention through the beginning of the inspection activities, and the role of the Korean people in becoming psychological stable and efforts to be born as safety experts are required. Finally, it is necessary to establish a concrete manual, strategic safety inspection plan.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.403-411
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• 2016

Recently, the number of occurrences of inundation and the severity of flood damage has increased rapidly as the frequency of localized heavy rainfall and the ratio of impervious area increased in urban areas. Most local governments focus on employing structural measures (e.g., the construction of detention reservoirs/pump stations, rehabilitation of drainage and sewer pipes) to prevent urban inundation. On the other hand, the effectiveness of implementing such structural measures is being dimished because there are already many inundation prevention facilities. The limitation of structural measures can be overcoming by employing non-structure measures, such as flood alerts and the operation of drainage facilities. This study suggests the pump operation rule (i.e., suggesting pump stop level) for a new detention reservoir operating method, which triggers the operation of a pump based on the water level at the monitoring node in urban drainage system. In the new reservoir operation, a total of 48 rainfall events are generated by the Huff distribution for determining the proper pump stop level. First, the generated rainfall events are distributed as frequencies, quartiles, and durations. The averaged system resilience value was determined to range from 1.2 m to 1.5 m is based on the rainfall-runoff simulation with rainfall generated by the Huff distribution. In this range, 1.2 m was identified considering the safety factor of 1.25 by the Standard on sewer facilities in 2011.

• Journal of Korea Water Resources Association
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• v.55 no.4
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• pp.267-278
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• 2022

Recently Flood damage volume has increased as heavy rain has frequently occurred. Especially urban areas are a vulnerability to flooding damage because of densely concentrated population and property. A local government is preparing to mitigate flood damage through the heavy rain warning issued by Korea Meteorological Administration. This warning classification is identical for a national scale. However, Seoul has 25 administrative districts with different regional characteristics such as climate, topography, disaster prevention state, and flood damage severity. This study considered the regional characteristics of 25 administrative districts to analyze the flood vulnerability using entropy weight and Euclidean distance. The rainfall classification was derived based on probability rainfall and flood damage rainfall that occurred in the past. The result shows the step 2 and step 4 of rainfall classification was not significantly different from the heavy rain classification of the Korea Meteorological Administration. The flood vulnerability is high with high climate exposure and low adaptability to climate change, and the rainfall classification is low in the northern region of Seoul. It is possible to preemptively respond to floods in the northern region of Seoul based on relatively low rainfall classification. In the future, we plan to review the applicability of rainfall forecast data using the rainfall classification of results from this study. These results will contribute to research for preemptive flood response measures.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.5
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• pp.79-96
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• 2021

Green infrastructure planning represents landscape planning measures to reduce particulate matter. This study aimed to derive factors that may be used in planning green infrastructure for particulate matter reduction using text mining techniques. A range of analyses were carried out by focusing on keywords such as 'particulate matter reduction plan' and 'green infrastructure planning elements'. The analyses included Term Frequency-Inverse Document Frequency (TF-IDF) analysis, centrality analysis, related word analysis, and topic modeling analysis. These analyses were carried out via text mining by collecting information on previous related research, policy reports, and laws. Initially, TF-IDF analysis results were used to classify major keywords relating to particulate matter and green infrastructure into three groups: (1) environmental issues (e.g., particulate matter, environment, carbon, and atmosphere), target spaces (e.g., urban, park, and local green space), and application methods (e.g., analysis, planning, evaluation, development, ecological aspect, policy management, technology, and resilience). Second, the centrality analysis results were found to be similar to those of TF-IDF; it was confirmed that the central connectors to the major keywords were 'Green New Deal' and 'Vacant land'. The results from the analysis of related words verified that planning green infrastructure for particulate matter reduction required planning forests and ventilation corridors. Additionally, moisture must be considered for microclimate control. It was also confirmed that utilizing vacant space, establishing mixed forests, introducing particulate matter reduction technology, and understanding the system may be important for the effective planning of green infrastructure. Topic analysis was used to classify the planning elements of green infrastructure based on ecological, technological, and social functions. The planning elements of ecological function were classified into morphological (e.g., urban forest, green space, wall greening) and functional aspects (e.g., climate control, carbon storage and absorption, provision of habitats, and biodiversity for wildlife). The planning elements of technical function were classified into various themes, including the disaster prevention functions of green infrastructure, buffer effects, stormwater management, water purification, and energy reduction. The planning elements of the social function were classified into themes such as community function, improving the health of users, and scenery improvement. These results suggest that green infrastructure planning for particulate matter reduction requires approaches related to key concepts, such as resilience and sustainability. In particular, there is a need to apply green infrastructure planning elements in order to reduce exposure to particulate matter.

• Journal of Korean Society of Forest Science
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• v.79 no.3
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• pp.269-277
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• 1990

In planning the disaster prevention by the erosion control facilities, it is essential to focus on the microtopography of the channel bed and the chronological process of sedimental movement in the torrential streams. For this purpose, the microtopographical change of the channel bed and the effects of the erosion control facilities in the mountain torrents were analyzed by the experimental channel and the field survey of the torrents where low-dam series had been constructed in the channel. The results of this experiment showed that the effects of construction of the low-dam series on the channel bed fixiation were the prevention of the local scouring in the experimental channel and the expansion of flow channel width and deposit space. The results are summarized as follows : 1. When the low-dam series were constructed over the whole channel bed (L'/L=1), the conning water and the sediment were seperated, simultaneously resulting in deposition of sediment and reduction of the tractive force for the running water. Therefore, the F.A. (Fluctuation area in cross-section: value was decreased to about 65% compared with that of non-work (L'/L=0). 2. The efficiencies of the low-dam series on the channel width were increased with an increment in length of working space. After the construction of low-dam series on the whole channel bed (L'/L=1), flow channel width was increased to about 1.53 times compared with that of non-work (L'/L=0). 3. It needs a deposition area to store the sediment with decrease in tractive force. The low-dam series in the experimental channel widened the deposition area about 2.10 times compared with that of non-work.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.3
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• pp.146-160
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• 2020

In the 4th industrial revolution, research on solving urban problems using ICT technology is emerging. Representatively, research is being conducted mainly focusing on smart cities. 3D geo-spatial. Various case studies on smart cities are being conducted to solve urban problems, and in order to effectively implement smart cities, it is implemented on the basis of a digital twin interconnecting physical and virtual environments. To implement a digital twin, the concept of space is essential, and spatial information that composes the real world is also essential. Therefore, in order to implement the digital twin, this study conducted a study on the construction and modeling of 3D geo-spatial information based on the national spatial information establishment regulations and the international standard CityGML for buildings, water facilities, and transportation facilities in Jeonju. In Jeonju, the research area, the LOD was defined, and the possibility of digital twin based on geo-spatial information was determined through data collection, analysis, and construction for each detail. In this study, it is meaningful that a plan to construct geo-spatial information for the implementation of a digital twin is presented, and the result of the construction is modeled as an urban standard model. The results of study are expected to be used as reference for detailed construction plans and standard establishment by governments and local governments promoting smart city and digital twin construction in the future.