• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1077-1086
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• 2013

Recent huge losses of both life and property have occurred by unexpected natural disasters. We studied snow damages, an important natural disaster issue because it happens more frequently in recent years. This study tries to select vulnerable areas of snowfall in advance and then establish climate change adaptation policy for minimizing unexpected snowfall damage. Busan, where is our study area, has hilly in downtown areas so that topography characteristics of the roads such as slope, elevation and aspect are vulnerable to snowfall. The sudden snowfall in Busan causes traffic jam and causes some schools in hilly to close some schools. At this moment, the adaptation policy has to be established for infrastructure (such as roads) in advance, because prediction of anomaly climate due to global warming is so difficult beside the damage of natural disaster is huge. Therefore, the purpose of this study is contribute to selecting and assessing vulnerable zones of snow damage focusing topography characteristics of the roads and then evaluating the degree of risk of vulnerable zones.

• Structural Engineering and Mechanics
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• v.74 no.1
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• pp.1-18
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• 2020

For the large deformation of shear walls under vertical and horizontal loads, there are difficulties in obtaining accurate simulation results using the response analysis method, even with fine mesh elements. Furthermore, concrete material nonlinearity, stiffness degradation, concrete cracking and crushing, and steel bar damage may occur during the large deformation of reinforced concrete (RC) shear walls. Matrix operations that are involved in nonlinear analysis using the traditional finite-element method (FEM) may also result in flaws, and may thus lead to serious errors. To solve these problems, a planar four-node element was developed based on vector mechanics. Owing to particle-based formulation along the path element, the method does not require repeated constructions of a global stiffness matrix for the nonlinear behavior of the structure. The nonlinear concrete constitutive model and bilinear steel material model are integrated with the developed element, to ensure that large deformation and damage behavior can be addressed. For verification, simulation analyses were performed to obtain experimental results on an RC shear wall subjected to a monotonically increasing lateral load with a constant vertical load. To appropriately evaluate the parameters, investigations were conducted on the loading speed, meshing dimension, and the damping factor, because vector mechanics is based on the equation of motion. The static problem was then verified to obtain a stable solution by employing a balanced equation of motion. Using the parameters obtained, the simulated pushover response, including the bearing capacity, deformation ability, curvature development, and energy dissipation, were found to be in accordance with the experimental observation. This study demonstrated the potential of the developed planar element for simulating the entire process of large deformation and damage behavior in RC shear walls.

• Journal of the Society of Disaster Information
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• v.19 no.1
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• pp.69-75
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• 2023

Purpose: The risk of disaster from extreme weather events is increasing due to the increase in occurrence and the strength of heavy rains and storms from continued climate change. To reduce these risks, emergency weather information customized for the characteristics of the information users and related circumstances should be provided. Method: A first-stage emergency weather information delivery system has been developed to provide weather information to the disaster-risk area residents and the disaster response personnel. Novel methods to apply artificial intelligence to identify emergencies have been studied. The relationship between special weather reports from meteorological administration and disaster-related news articles has been analyzed to identify the significance of a pilot study using text analytic artificial intelligence. Result: The basis to identify the significance of the relations between disaster-related articles and special weather reports has been established and the possibility of the development of a real-world applicable system based on a broader analysis of data has been suggested. Conclusion: Through direct alert delivery of weather emergency alerts, a weather emergency alert system is expected to reduce the risk of damage from extreme weather situations.

• Journal of Korean Society of Disaster and Security
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• v.6 no.3
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• pp.49-57
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• 2013

This paper is to show the long-term roadmap by analyzing the development trend for the safety technology of facility disaster in the country and abroad, and it is designed to plan the long term and roadmap in response to change the disaster environment. Recently in the country, it is increasing the needs of the long term roadmap design of the facility disaster research development in the facility disaster, by the repidly of the social and the living and the related governments response's changing. The U.S. is going to develop the disaster responding research by planning the its master plans, including the NRF (National Responing Framwork), the NIMS (National Incident Management System), and its sinarios etc.. Japan is going to develop the research planning in the annual report of the disaster prevention, and we going to do the study projects about the facility disaster area with the NEMA (National Emergency Management Agency) and NDMI (National Disaster Management Institute). This paper is showed to design the long term roadmap of the facility disaster's study development, and to minimize the damage of the man and his property, and to set the study development system of the national facility disaster, and furthering to make the resilient planning in changing of the facility disaster's environment.

• Journal of Korean Society of Disaster and Security
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• v.11 no.2
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• pp.53-60
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• 2018

To diagnosis the local damages of the steel plates, magnetic flux leakage (MFL) method that is known as a adaptable non-destructive evaluation (NDE) method for continuum ferromagnetic members was applied in this study. To analysis the sensitivity according to thickness of steel plate in MFL method based damage diagnosis, several steel plate specimens that have different thickness were prepared and three depths of artificial damage were formed to the each specimens. To measured the MFL signals, a MFL sensor head that have a constant magnetization intensity were fabricated using a hall sensor and a magnetization yoke using permanent magnets. The magnetic flux signals obtained by using MFL sensor head were improved through a series of signal processing methods. The capability of local damage detection was verified from the measured MFL signals from each damage points. And, the peak to peak values (P-P value) extracted from the detected MFL signals from each thickness specimen were compared each other to analysis the MFL based local damage detection sensitivity according to the thickness of steel plate.

• Wind and Structures
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• v.26 no.2
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• pp.75-87
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• 2018

A large number of low-rise buildings experienced serious roof covering failures under strong wind while few suffered structural damage. Clay and concrete tiles are two main kinds of roof covering. For the tile roof system, few researches were carried out based on Finite Element (FE) analysis due to the difficulty in the simulation of the interface between the tiles and the roof sheathing (the bonding materials, foam or mortar). In this paper, the FE analysis of a single clay or concrete tile with foam-set or mortar-set were built with the interface simulated by the equivalent nonlinear springs based on the mechanical uplift and displacement tests, and they were expanded into the whole roof. A detailed wind tunnel test was carried out at Tongji University to acquire the wind loads on these two kinds of roof tiles, and then the test data were fed into the FE analysis. For the purpose of validation and calibration, the results of FE analysis were compared with the full-scale performance ofthe tile roofs under simulated strong wind impact through one-of-a-kind Wall of Wind (WoW) apparatus at Florida International University. The results are consistent with the WoW test that the roof of concrete tiles with mortar-set provided the highest resistance, and the material defects or improper construction practices are the key factors to induce the roof tiles' failure. Meanwhile, the staggered setting of concrete tiles would help develop an interlocking mechanism between the tiles and increase their resistance.

• Journal of Korea Water Resources Association
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• v.55 no.6
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• pp.471-480
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• 2022

In this study, a integrated platform applied with various analysis and evaluation models and data collection modules was developed for urban river management. Modules applied to the integrated platform are data collection and provision module, flood analysis module, river evaluation module, and levee breach simulation module, which were selected and applied for efficient urban river management. The integrated platform collects data for application to analysis and evaluation modules from various institutions. The collected data is refined through pre-processing and stored. The stored data is used as input data for each module and is also provided as an Open API through the platform. The flood analysis module is provided to analyze and prepare for floods occurring in cities and rivers. The river evaluation module is used for river planning and management by evaluating rivers in various ways. Finally, the levee breach simulation module can be used to establish countermeasures by deriving a possible damage area due to levee breach through analysis of a virtual breach situation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.2
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• pp.259-266
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• 2023

Global climate change is increasing, and the damage and scale of localized torrential rains are increasing. Pre-flood analysis simulation results should be derived from rainfall data through rainfall forecasts to prevent flood damage. In addition, it is necessary to control the use and management of flood response disaster prevention facilities through immediate decision-making. However, methods using spills and flood models such as XPSWMM and GATE2018 are limited due to professional usability and complex analytical procedures. Prototype (flood disaster prevention facility simulator) of this study is developed by calculating rainfall (short-term and long-term) using CBD software development methods. It is also expected to construct administrator and user-centric interfaces and provide GIS and visible data (graphs, charts, etc.).

• Proceedings of the Korean Society of Disaster Information Conference
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• 2022.10a
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• pp.347-348
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• 2022

본 연구에서는 무인이동체를 활용한 철도교량의 외관조사 점검을 보다 효율적이고 객관성 있게 수행하기 위하여 무인이동체를 통해 촬영된 이미지를 딥러닝 기반 분석기술을 활용하여 손상 자동으로 분석 하기위한 기술을 연구하였다. 철도교량의 외관 손상 중 균열, 콘크리트 박리·박락, 누수, 철근노출에 대한 손상 이미지를 추출하여 딥러닝 분석 모델을 생성하고 학습한 분석 모델을 적용한 시스템을 실제 현장에 적용 테스트를 수행하였으며 학습 구현된 분석모델의 검측 재현율을 검토한 결과 평균 95%이상의 감지성능을 검토할 수 있었다. 개발 제안된 자동손상분석 기술은 기존 육안점검 결과 대비 보다 객관적이고 정밀한 손상 검측이 가능하며 철도 유지관리 분야에서 무인이동체를 활용한 외관조사 업무를 수행함에 있어 기존 대비 객관적인 결과도출과 소요시간, 비용저감이 가능할 것으로 기대된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7357-7363
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• 2014

Korea had been known as safe region regarding volcanic disasters. On the other hand, Baekdu mountain experienced a large eruption one thousand years ago and the precursor phenomena for a volcanic eruption have been frequently reported these days. Therefore, a number of volcano experts, who warn of a volcanic eruption on the Korean peninsula, has increased. This paper describes the utilization plan and evolution of developing volcanic disaster response system based on spatial information and scientific modeling process for Baekdu mountain. First, the business processes for volcanic disaster response are derived based on an analysis of business system and related IT-based systems. Second, the design and development of a volcanic disaster response system are derived based on the business process. Third, a utilization plan is suggested to maximize the efficiency of the system. The application of the suggested volcanic disaster response system to NEMA, additional tests and system supplementation should be carried out. The complete volcanic disaster response system, which will be implemented based on this research, is expected to minimize the volcanic disaster damage in the area of Korea, China and Japan.