• Journal of the Korean GEO-environmental Society
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• v.22 no.12
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• pp.15-24
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• 2021

In Korea, which is mostly mountainous, the proportion of tunnel and underground space development are increasing. Although the ground is reinforced by applying the ground improvement method during underground space development, accidents still occur frequently in Korea. In the grouting method, a representative ground reinforcement method, the effect was judged by comparing the total amount of injection material with the amount of injection material used during the actual grouting construction. However, it is difficult to determine whether the ground reinforcement is properly performed during construction or within the target ground. In order to solve this problem, it is necessary to study a new method for quality control during or after construction by measuring electrical resistivity after performing grouting by mixing carbon fiber, which is a conductive material, and microcement, which is a grout material. In this study, as a basic study, a cement specimen mix ed with 0%, 3%, 5%, 7% of carbon fiber was prepared to evaluate the performance of the grout material mixed with carbon fiber, which is a conductive material. The prepared specimens were wet curing for 3 days, 7 days, and 28 days under 99% humidity, and then compression wave velocity and shear wave velocity were measured. As a result of the compression wave velocity and shear wave velocity measurement, it showed a tendency to increase with the increase in the compounding ratio of carbon fibers and the number of days of age, and it was confirmed that the elastic modulus and shear modulus, which are the stiffness of the material, also increased.

• Journal of the Society of Disaster Information
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• v.17 no.4
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• pp.710-721
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• 2021

Purpose: The purpose of this study is to prepare an environment that can provide high-quality 119 rescue services by analyzing the causes of casualties at the water rescue and suggesting improvement plans to prevent them. Method: 5 major cases were analyzed among firefighters' casualty accidents during rescue activities related to the water over the past 10 years for case study. And the causes of the accidents were analyzed in terms of 4 values (Man, Machine, Media, Management) through the 4M analysis technique. Result: ① man: the main causes are lack of awareness of on-site safety, etc ② machine: the problem of the absence of the equipment itself, etc ③ media: the lack of information on the rescue site and the poor rescue environment conditions, ④ management : the main causes were the absence and inadequacy of the response manual for each rescue site, Conclusion: ① man: knowledge of SOP and reinforcement of education and training, etc. ② machine: there are measures such as the introduction of equipment suitable for the changing rescue site, ③media: providing sufficient information about the rescue activity environment and conducting regular road training, ④ management: policy suggestions such as establishment and dissemination of on-site safety management plans and manuals were derived.

• Journal of the Society of Disaster Information
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• v.19 no.1
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• pp.1-9
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• 2023

In order to carry out construction work, it is urgent to introduce a proper wage system so that the cost burden of projects that have been won due to bleeding competition among original government buildings based on low-priced bids can be transferred to subcontractors. Purpose: Construction with illegal multi-level industrial structure needs to improve the wage reduction environment leading to order (100%) → original contractor (80%) → subcontractor (65%) → load contractor (65%) and aims to ensure wages for end workers. Method: Investigate the current status of labor cost appropriate payment plan in the construction industry, and investigate the case of the appropriate wage system (P.W) in the United States. In addition, the effect and direction of the appropriate wage system are presented. Result: Individual minimum wage security was also mentioned in the Constitution, and many researchers suggested that only the introduction of an appropriate wage system could solve the problem of reducing worker labor and ensure quality and safety. Conclusion: The proper wage system in the construction industry will block illegal multi-level and illegal foreign work, improve the labor environment in the construction market, create an influx of young workers, and have a significant impact on the construction industry's competitive structure, safety, and quality.

• Journal of the Society of Disaster Information
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• v.18 no.4
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• pp.713-728
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• 2022

Purpose: This study examined the effect of VR safety education content quality on behavioral intention and collect operational opinions through interview. Method: Based on the survey data of 93 former and current officers, the hypothesis was verified. In addition, 15 fire safety experience centers were visited to conduct interview. Result: For the quality of VR safety education contents, immersion and convenience had a significant effect on usage satisfaction, recommendation intention, and field application intention. In addition, convenience and aesthetic experience had a significant effect on the educational effect, but immersion and diversity did not significant. In the interview, they suggested that VR education has high user satisfaction and good educational effects. The quality of content(particularly immersion and convenience) is an important factor in VR education. In the long-term persepective, it is necessary to prepare a standard teaching plan for each disaster, in addition, manpower, expertise, maintenance problems, and etc. Conclusion: Through these results, it was confirmed that VR experience content quality affects behavioral intention and educational effect and that efforts and investments to improve content quality are needed to enhance the effectiveness of VR experience education. And the contents derived from the interview will be helpful in the operation of an effective fire safety experience center.

• Journal of the Society of Disaster Information
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• v.18 no.4
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• pp.883-890
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• 2022

Purpose: Currently, in the case of domestic fire fighting facility design, it is difficult to secure highquality manpower due to low design costs and overheated competition between companies, so there is a limit to improving the fire safety performance of buildings. Accordingly, AI-based firefighting design solutions were studied to solve these problems and secure leading fire engineering technologies. Method: Through AutoCAD, which is widely used in existing fire fighting design, the procedures required for basic design and implementation design were processed, and AI technology was utilized through the YOLO v4 object recognition deep learning model. Result: Through the design process for fire fighting facilities, the facility was determined and the drawing design automation was carried out. In addition, by learning images of doors and pillars, artificial intelligence recognized the part and implemented the function of selecting boundary areas and installing piping and fire fighting facilities. Conclusion: Based on artificial intelligence technology, it was confirmed that human and material resources could be reduced when creating basic and implementation design drawings for building fire protection facilities, and technology was secured in artificial intelligence-based fire fighting design through prior technology development.

• Journal of the Society of Disaster Information
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• v.19 no.3
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• pp.451-470
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• 2023

Purpose: Since COVID-19 was first discovered in China in December 2019, it has rapidly spread around the world, causing serious economic and social problems not only in individuals' lives, but also in businesses and countries. Individuals, businesses, and governments have all made various efforts to prevent the spread of COVID-19. Although the roles of individuals, companies, and the government are important to respond to and manage infectious diseases, previous studies have only partially studied the roles. Therefore, in this study, the roles of individuals, companies, and the government to achieve results in responding to infectious diseases disaster management A comprehensive study was conducted on this issue, and it was attempted to understand the impact of workers' perceptions of infectious disease disaster management and government and corporate capabil]ities on disaster response performance. Method: The survey was conducted for workers in the automobile manufacturing industry in Ulsan, Gyeongju, and Yangsan, and frequency analysis, factor analysis, correlation analysis, and regression analysis were performed. Result: It was found that worker perception had a positive effect on both government and corporate capabilities as well as disaster management performance. In addition, government capacity and corporate capacity had a positive effect on disaster management performance. Conclusion: The results of this study are meaningful in that they reveal that not only workers' perceptions but also the capabilities of the government and companies are important to achieve disaster response performance. In addition, workers should make good use of opportunities for education and participation provided by the government and corporations, and make the most social efforts that workers can make.

• Journal of the Society of Disaster Information
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• v.19 no.3
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• pp.737-746
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• 2023

Purpose: Ground subsidence due to cavity can bring about various problems, such as casualties, decrease of the safety of the structures, and indirect social costs. Therefore, ground subsidence should be prevented through the exploration and recovery of the cavity under the pavements. Method: In this study, GPR exploration method was carried out on both actual roadway and mock-up site to compensate for the problems caused by excavation and restoration process. Result: This study compared the cavity scales obtained from GPR exploration results and the direct excavation of the identified cavity. It was confirmed that the predicted soil depth by GPR exploration was similar to the identified soil depth, but the predicted cavity scale by GPR exploration overestimated the longitudinal and cross-sectional widths compared to the identified cavity scale. Conclusion: Based on the correlation between the predicted cavity scales by GPR exploration, it is possible to qualitatively estimate the cavity scales using the empirical formula proposed in this study.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.4
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• pp.86-93
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• 2023

A bridge health monitoring technology is under development for the safety management of aged bridges. The bridge health monitoring technology has been developed mainly for single bridge management at a large scale, so it uses wire-based systems for power supply and data transfer. However, the wire-based systems need to be improved for the sporadically distributed small-sized bridges on local roads. This study proposed a wireless structural health monitoring system for small-sized bridges. The proposed monitoring system overcomes the limitations of wired systems by providing wireless power through solar power and utilizing LTE technology to transmit measurement data. In addition, a remote control system and power management plan were proposed to ensure the stability of the bridge measurement system. The proposed measurement system was installed on 32 bridges on fields and verified the operability by collecting 80.6% of measurement data for one year. The proposed system can support the health monitoring of aged bridges on local roads.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.4
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• pp.94-103
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• 2023

Built in urban ares tunnels is necessary to accurately grasp not only the above-ground environment of the tunnel but also the below-ground environment of the tunnel for design and construct. However, fully coupled analysis of stress and flow is very difficult due to the limited function of the tunnel numerical analysis program and difficulty in using program. This can lead to excessive design that increases the construction cost or occur problems that can lead to accidents during construction. In particular, in the case of an urban tunnel has a low layer soil section above the tunnel and the groundwater level exists in the upper layer of the tunnel. Therefore, a reduction in the groundwater level during underground construction may increase the effective stress of the upper layer and cause the ground to subsidence. So It is necessary to design after accurately evaluating the change in the groundwater level. In this study, the tunnel's behavioral characteristics were analyzed through fully coupled analysis of stress and flow according to the drainage type for an urban underground tunnel.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.4
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• pp.70-77
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• 2023

Fine dust is a cause of serious ecological problems, and fugitive dust generated from construction sites is a major source of fine dust in Korea. However, at construction sites, including concrete manufacturing industry sites, measurements are rarely made at the fugitive dust generation stage, and passive removal methods are the majority. Therefore, in this study, a fugitive dust measurement method suitable for managing fugitive dust generated during aggregate unloading in the concrete manufacturing industry sites was selected. In addition, the purpose was to analyze the amount of fugitive dust reduction according to the operation of the reduction system by applying the automatic fugitive dust reduction system to the aggregate unloading site. As a result, the reliability of the light scattering method was secured through the comparative measurement of the beta-ray absorption method and the light scattering method, and the light scattering method correction coefficient was calculated and applied to the measured value of the fugitive dust particle mass concentration at the concrete manufacturing industry sites. In addition, the fugitive dust reduction rate according to the operation of the automatic fugitive dust reduction system was derived.