• Earthquakes and Structures
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• v.9 no.1
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• pp.173-194
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• 2015

Site response analysis is an important topic in earthquake engineering. A time-domain numerical method called as one-dimensional (1D) finite element artificial boundary method is proposed to simulate the homogeneous plane elastic wave propagation in a layered half space subjected to the obliquely incident plane body wave. In this method, an exact artificial boundary condition combining the absorbing boundary condition with the inputting boundary condition is developed to model the wave absorption and input effects of the truncated half space under layer system. The spatially two-dimensional (2D) problem consisting of the layer system with the artificial boundary condition is transformed equivalently into a 1D one along the vertical direction according to Snell's law. The resulting 1D problem is solved by the finite element method with a new explicit time integration algorithm. The 1D finite element artificial boundary method is verified by analyzing two engineering sites in time domain and by comparing with the frequency-domain transfer matrix method with fast Fourier transform.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1342-1348
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• 2010

Currently available evaluation checklists are developed for specific purposed using different parameters and items determined by different weighting factors. Those items with different weighting are sometimes said that they are based on the engineering judgement and leap of faith and, therefore, there is a limitation to adapt those checklists for slope-stability evaluation in the field. This study reviews factors affecting slope stability, analyze the relationship between those factors and slope failures using artificial neural network, and proposed a slope-stability evaluation model for adequate weighting for the factors.

• Journal of the Korean Society of Safety
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• v.31 no.6
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• pp.84-92
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• 2016

Since the mankind started its space mission, the number of artificial space objects has been increasing exponentially. It contains not just the space machines which are in use but the machines which are out of order. Meantime, those dead machines are being a serious danger, a real threat to human's lives and property because of it could re-enter into the earth's atmosphere and fall to the ground causing mega-disaster. As the number of space activities gets growing so far, the re-entry of the space objects will be a lot more happened in the future. Therefore, not just natural space object like asteroids but the artificial space object like artificial satellite and space station can cause the disaster by falling to the ground. To protect our nation and our property, the government has set up the space disaster management center in Korea astronomy and Space science Institute. In this study, we surveyed public's recognition of the space object's re-entry situation and analyzed it to contribute building national space disaster management policy.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.12
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• pp.1612-1617
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• 2020

Recently, research to reduce the accident rate by actively adopting artificial intelligence technology in the field of disaster safety technology is spreading. In particular, it is important to quickly search the Rescue Requester in order to effectively perform rescue activities at the disaster site. However, it is difficult to search for Rescue Requester due to the nature of the disaster environment. In this paper, We intend to develop an artificial intelligence system that can be operated in a smart helmet for firefighters to search for a rescue requester. To this end, the optimal SoC was selected and developed as an embedded system, and by testing a general-purpose artificial intelligence S/W, the embedded system for future smart helmet research was verified to be suitable as an artificial intelligence S/W operating platform.

• 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.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2022.10a
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• pp.57-58
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• 2022

지속되는 기후변화에 의한 풍수해의 발생 빈도와 강도가 증가함에 따라 풍수해 등 극한 기상현상이 지역 및 상황에 따라 재난으로 이어지는 위험성이 높아지고 있어 기상정보 사용자 및 환경에 따라 서로 다른 기상정보의 중요성과 필요성이 급증하고 있다. 이와 같은 수요를 맞추고자 기상 재난에 의한 피해 위험 지역 거주 주민과 재난 현장에서 재난에 대응하는 방재 관계기관 등 특정 사용자의 요구와 필요에 특화된 맞춤형 기상긴급정보를 다양한 매체의 특성에 맞게 즉각적으로 생성하여 전달하기 위한 기상긴급정보전달시스템이 개발되고 있으며 인공지능을 활용한 긴급성의 식별과 정보 생성 방안이 연구되고 있다.

• Journal of the Society of Disaster Information
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• v.19 no.1
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• pp.76-83
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• 2023

Purpose: In emergency situations such as earthquakes, heavy rains, typhoons, or fires, when quick delivery of emergency alerts is crucial, the hearing impaired are the ones who are the most disadvantaged and vulnerable when alerts are only delivered through auditory or text alerts. They can't perceive auditory information, and many have difficulties in fast understanding text-based alerts. Method: An alert system that can deliver pictograms for specific disaster situations has been devised. Then, a novel approach based on artificial intelligence has been studied so that the pictograms for specific disaster situations can be chosen instantly once a disaster alert is issued in text. Result: A disaster alert system that delivers pictograms for specific disaster situations was developed and a novel method has been suggested for automatic delivery. Conclusion: A system to instantaneously deliver disaster alert information in pictograms has been developed to improve alert delivery to the populations vulnerable to disaster due to hearing impairment by the instantaneous understanding of disaster situations through visual information.

• Earthquakes and Structures
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• v.13 no.6
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• pp.573-588
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• 2017

The earthquake input is required when the soil-structure interaction (SSI) analysis is performed by the direct finite element method. In this paper, the earthquake is considered as the obliquely incident plane body wave arising from the truncated linearly elastic layered half space. An earthquake input method is developed for the time-domain three-dimensional SSI analysis. It consists of a new site response analysis method for free field and the viscous-spring artificial boundary condition for scattered field. The proposed earthquake input method can be implemented in the process of building finite element model of commercial software. It can result in the highly accurate solution by using a relatively small SSI model. The initial condition is considered for the nonlinear SSI analysis. The Daikai subway station is analyzed as an example. The effectiveness of the proposed earthquake input method is verified. The effect of the obliquely incident earthquake is studied.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.828-835
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• 2019

An artificial rainfall system is used widely as a research tool for generating model experiment data. Artificial rainfall devices have been used in many studies, but studies of the rainfall distribution are not considered as important issues. To simulate various rainfall characteristics, it should be possible to simulate from low to high intensity, and the homogeneity of the rainfall distribution should be ensured. In this study, the maximum rainfall intensity was set to 130mm/hr and controlled by 10mm/hr. In addition, the aim was to secure a uniform coefficient value of 80% or more. To this end, rainfall tests were performed according to the nozzle type, diameter, position, and pump pressure. The rainfall test showed that the circular nozzle was suitable, and the nozzle size was 1.9mm and 1.4mm. The optimal pump pressure was found to be 3~6kg/㎠. The rainfall intensity tended to increase linearly with increasing pump pressure. Based on the rainfall test results, a rainfall control manual was produced with variables, such as pump pressure, nozzle type, and number of nozzles. As a result of rainfall verification, rainfall intensity showed a 3.1% error with a uniformity coefficient of 86%.

• Journal of the Korean Geotechnical Society
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• v.40 no.1
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• pp.39-46
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• 2024

Artificial recharge systems have been employed to solve drought problems due to global climate change. Despite the increased usage, the applications of artificial recharge systems are limited by clogging problems, which reduce recharge rates. In this study, the soil texture and mineral characteristics of alluvial soil in a planned artificial recharge system area were investigated to evaluate the possibility of chemical clogging during the injection of stream water. The primary minerals contained in the clastic particles are quartz, K-feldspar, plagioclase, and biotite, and the secondary minerals filling the pore space are illite, kaolinite and Fe-oxide. The fact that carbonate and sulfate are observed as secondary minerals in the pore space suggests that chemical clogging has not occurred by the interaction between the groundwater and surface water in the study area. Thus, monitoring soil properties, e.g., the formation and growth of secondary minerals in the pore space, is required to investigate the possibility of chemical clogging in artificial recharge systems.