• Journal of the Society of Disaster Information
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• v.18 no.2
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• pp.241-251
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• 2022

Purpose: In the event of a fire in a high-rise building, if the smoke control area is not effectively protected, smoke or flames enter the stairwell, making it difficult to evacuate. When inflowing air is discharged from a closed corridor, a negative pressure is formed in the corridor, the pressure in the smoke control area becomes excessively high, and the force required to open the door during evacuation is exceeded. Also, if the air introduced into the hallway is not exhausted, the smoke may flow back into the smoke control area. This paper tried to identify the problems caused by the inflowing air and to find out how to improve the performance. Method: Using the CONTAM program, simulations were performed with the basic conditions and the modified conditions. Result: If the inflowing air was discharged from the sealed corridor, overpressure occurred in the Smoke Control Area and exceeded the opening force, and the prevent smoke backflow was insufficient in the layer where the inflowing air was not discharged. Conclusion: "Differential pressure exhaust damper" application, simultaneous opening of two exhaust dampers, and automatic window installation between corridors and outdoors improved the exhaust performance of inflowing air.

• Korean Journal of Remote Sensing
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• v.38 no.5_2
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• pp.661-667
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• 2022

As remote sensing and GIS have been considered to be essential technologies for disasters information production, researches on developing methods for analyzing spatial data, and developing new technologies for such purposes, have been actively conducted. Especially, it is assumed that the use of remote sensing and GIS for disaster management will continue to develop thanks to the launch of recent satellite constellations, the use of various remote sensing platforms, the improvement of acquired data processing and storage capacity, and the advancement of artificial intelligence technology. This spatial issue presents 10 research papers regarding ship detection, building information extraction, ocean environment monitoring, flood monitoring, forest fire detection, and decision making using remote sensing and GIS technologies, which can be applied at the disaster prediction, monitoring and response stages. It is anticipated that the papers published in this special issue could be a valuable reference for developing technologies for disaster management and academic advancement of related fields.

• Journal of the Korean Applied Science and Technology
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• v.38 no.6
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• pp.1533-1542
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• 2021

Eco-friendly polyurethane can be defined as a highly utilized material used in various fields. The various structural properties of the synthesis of isocyanates and polyols provide versatility and customization for use in the manufacturing field. The characteristics of polyurethane vary widely from soft touch coatings to hard building materials like rocks. These mechanical, chemical and biological properties and ease of alignment are drawing tremendous attention not only in the field of research but also in related industries. In order to improve the performance of water-dispersible polyurethane materials, it can be derived through processes such as adjusting the blending of raw materials and adding additives and nanomaterials. This study highlights the basic chemical structure of eco-friendly water-dispersible polyurethane in the fields of medical science, automobiles, coatings, adhesives, paints, textiles, marine industries, wood composite materials, and clothing.

• Journal of the Korean Institute of Rural Architecture
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• v.24 no.3
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• pp.31-38
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• 2022

The purpose of this study is to rediscover the gestalt psychological value of the Landscaping structure and architectural landscape in the vulnerable village consulted by experts in 2021 year. For this study, nine villages called of Saethul Maul were surveyed, and two of them were analyzed for landscape composing of gestalt psychology. The two villages, Yulwon and Jeonchon, included the case where the landscaping structure of residence was viewed from outside the village and the case from within the village. Psychological distance of the villages is analyzed by D/H ratio for the scenery seen from lanes. There are three expected conclusions. First, in terms of gestalt psychology, the buildings mean a figure, and the rice field in front of the village, the mountains behind the village, and the lanes represent a landscape structure consisting a background(ground). It captures the unique landscape aesthetics of the vulnerable village. Second, the landscape seen in the village shows various differences in horizontal distance and vertical height of the lane, so even if the psychological distance gives a sense of closure, it gives a sense of rhythm and change. However, considering the psychological distance (D/H ratio) when the roads are expanded for the fire car, the village landscape can be re-formed by safety and function. Third, the architectural landscape of Yulwon village is characterized by the harmonious arrangement of traditional houses, Narack-Doiji (rice barn), and wooden building (agricultural barn) in the background of chestnut tree hill behind the village. It is necessary to reduce the use of industrial materials and restore the valuable architectural landscape of the vulnerable village.

• Steel and Composite Structures
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• v.46 no.4
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• pp.497-512
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• 2023

Using light weight concrete as infill material in conventional cold-formed steel (CFS) shear wall systems can considerably increase their load bearing capacity, ductility, integrity and fire resistance. The compressive strength of the filler concrete is a key factor affecting the structural behaviour of the composite wall systems, and therefore, achieving maximum compressive strength in lightweight concrete while maintaining its lightweight properties is of significant importance. In this study a new type of optimum polystyrene lightweight concrete (OPLC) with high compressive strength is developed for infill material in composite CFS shear wall systems. To study the seismic behaviour of the OPLC-filled CFS shear wall systems, two full scale wall specimens are tested under cyclic loading condition. The effects of OPLC on load-bearing capacity, failure mode, ductility, energy dissipation capacity, and stiffness degradation of the walls are investigated. It is shown that the use of OPLC as infill in CFS shear walls can considerably improve their seismic performance by: (i) preventing the premature buckling of the stud members, and (ii) changing the dominant failure mode from brittle to ductile thanks to the bond-slip behaviour between OPLC and CFS studs. It is also shown that the design equations proposed by EC8 and ACI 318-14 standards overestimate the shear force capacity of OPLC-filled CFS shear wall systems by up to 80%. This shows it is necessary to propose methods with higher efficiency to predict the capacity of these systems for practical applications.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.473-480
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• 2023

This study evaluated a novel method of defining the automatic flight path of unmanned aerial vehicles (UAVs) for search and rescue missions in a VR environment. The developed VR content reserves miniature digital twins of a building in the fire and a steep mountain terrain site. The users drow the UAV's scanning path using hand gestures on the surface of digital twins, and then the UAV make an automatic flight along the defined path. According to human-in-the-loop simulation tests comparing the novel method with a conventional manual flight task with 19 participants, the novel method did not improve the mission performance but participants felt a lower mental workload. The designer may need to consider the automation support on the vulnerable points of the SAR mission environment while maintaining experts' mapping capability.

• Wind and Structures
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• v.36 no.6
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• pp.405-421
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• 2023

Strong wind is the main factors of wind-damage of high-rise buildings, which often creates largely economical losses and casualties. Wind pressure plays a critical role in wind effects on buildings. To obtain the high-resolution wind pressure field, it often requires massive pressure taps. In this study, two traditional methods, including bilinear and bicubic interpolation, and two deep learning techniques including Residual Networks (ResNet) and Generative Adversarial Networks (GANs), are employed to reconstruct wind pressure filed from limited pressure taps on the surface of an ideal building from TPU database. It was found that the GANs model exhibits the best performance in reconstructing the wind pressure field. Meanwhile, it was confirmed that k-means clustering based retained pressure taps as model input can significantly improve the reconstruction ability of GANs model. Finally, the generalization ability of k-means clustering based GANs model in reconstructing wind pressure field is verified by an actual engineering structure. Importantly, the k-means clustering based GANs model can achieve satisfactory reconstruction in wind pressure field under the inputs processing by k-means clustering, even the 20% of pressure taps. Therefore, it is expected to save a huge number of pressure taps under the field reconstruction and achieve timely and accurately reconstruction of wind pressure field under k-means clustering based GANs model.

• Journal of the Korean Electrochemical Society
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• v.27 no.2
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• pp.55-72
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• 2024

Secondary batteries are used as an essential renewable energy source in our lives, such as electric vehicles and energy storage systems (ESS), as an alternative to fossil fuels due to global warming. However, cases of battery fires and explosions have been reported due to thermal runaway in secondary batteries due to various causes such as overdischarge, high-speed charging and discharging, and external short circuit, and great efforts are being made to find solutions suitable for each cause. In particular, as cases presumed to be caused by the overcharging process have been reported, this review will examine the chemical reactions of secondary batteries that can occur during the overcharging process and discuss risk investigation methods to check and prevent them.

• Steel and Composite Structures
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• v.51 no.3
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• pp.271-288
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• 2024

The primary objective of this study is to investigate the production and performance characteristics of structural concrete incorporating varying proportions (0%, 25%, and 50% by volume) of pumice stone, as well as aluminum lathe as an additive at 0%, 1%, 2%, and 3%, under fire conditions. The experiment will be conducted over a period of up to 1 hour, at temperatures ranging from 24℃, 200℃, 400℃ and 600℃. For the purpose of this, a total of twelve test samples were manufactured, and then tests of compressive strength (CS), splitting tensile strength (STS), and flexural strength (FS) were performed on these samples.Next, a comparison was made between the obtained values and the influence of temperature. To achieve this objective, the manufactured samples were placed at temperatures of 200℃, 400℃, and 600℃ for a duration of 1 hour, and were subjected to the influence of temperature.These values at 24 ℃ were then contrasted with the CS results obtained from test samples that were subjected to the temperature effect for an hour at 200 ℃, 400 ℃, and 600 ℃. A comprehensive analysis of the test outcomes reveals that the incorporation of aluminum lathe wastes into a mixture results in a significant reduction in the compressive strength of the concrete. As a result of this adjustment, the CS values dropped by 32.93%, 45.70%, and 52.07%, respectively. Furthermore, It was shown that testing the ratios of pumice stone alone resulted in a decrease in CS outcomes. Additionally, it was found that the presence of higher temperatures is clearly the primary factor contributing to the decrease in the strength of concrete. Due to elevated temperatures, the CS values decreased by 19.88%, 28.27%, and 38.61% respectively.After this investigation, an equation that explains the connection between CS and STS was provided through the utilization of the data of the experiments that were carried out.

• Journal of the Society of Disaster Information
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• v.20 no.2
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• pp.284-292
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• 2024

Purpose: Compared to general fires of the same size, underground parking lot fires are more likely to cause human and property damage and are not easy for firefighters to extinguish fire and save lives. This study attempted to find out how to secure the evacuation safety of parking lot users based on changes in the evacuation simulation behavior mode applied to evaluate the evacuation safety of the object. Method: Simulation for each CASE was performed using the Pathfinder program. Result: it was found that the higher the reference value, the higher the evacuation time, and Behavior showed an increase in time in SFPE mode rather than Steering mode. Priority was able to confirm an increase in time in priority designation rather than non-priority designation. Conclusion: The Required Safe Egress Time (RSET) for evaluating the evacuation safety of underground parking lots and the building evacuation design to ensure evacuation safety should be evaluated and reflected separately from Simulation's Behaviour Mode and Priority.