• Journal of Industrial Convergence
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• v.21 no.4
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• pp.165-170
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• 2023

There are cases where the mobility impaired have difficulty moving from the moment they leave the house. If guardians also do not have time to entrust their families, who are socially disadvantaged, to a shelter, the guardian has no choice but to check directly in order to know the location of the guardian. The AI home care solution was designed to relieve the anxiety and labor of caregivers and to provide convenience for protection facility officials and users. If more facilities distribute and use services free of charge to non-profit foundations and protective facilities, the concern of guardians will be reduced, and the burden of facility officials who have to manage facility users will be reduced. In this paper, we provide emergency notification services to guardians in the event of an emergency as well as location and status alarms for guardians, which are all data related to movement, in consideration of the mobility vulnerable. Furthermore, it is necessary to provide a service function that recommends the optimal route using a navigation function to ease the convenience and burden of facility officials. It is necessary to alleviate anxiety by providing necessary information to the guardian, such as the location of the shuttle used by the mobile weak and the time of getting on and off. In addition, while providing services for free, the goal is to improve the quality of service for facility managers and the quality of service for the mobility weak.

• Journal of the Korean GEO-environmental Society
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• v.24 no.9
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• pp.33-40
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• 2023

The lateral load which is applied to the pile foundation supporting the superstructure during an earthquake is divided into the inertia force of the upper structure and the kinematic force of the ground. The inertia force and the kinematic force could cause failure to the pile foundation through different complex mechanisms. So it is necessary to predict and evaluate interaction of the ground-pile-structure properly for the seismic design of the foundation. The interaction is affected by the lateral behavior of the structure, the length of the pile, the boundary conditions of the head, and the relative density of the ground. Confining pressure and ground stiffness change accordingly when the relative density changes, and it results that the coefficient of subgrade reaction varies depending on each system. Horizontal bearing behavior and capacity of the pile foundation vary depending on lateral load condition and relative density of the sandy soil. Therefore, the 1g shaking table tests were conducted to confirm the effect of the relative density of the dried sandy soil to dynamic behavior of the group pile supporting the superstructure. The result shows that, as the relative density increases, maximum acceleration of the superstructure and the pile cap increases and decreases respectively, and the slope of the p-y curve of the pile decreases.

• Journal of the Society of Disaster Information
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• v.19 no.3
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• pp.608-623
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• 2023

Purpose: Recently, the number of logistics warehouses has been on the rise. In addition, as the number of such logistics warehouses increases, number of fire accidents also increases every year, increasing the importance of preventing fires in large logistics warehouses. Method: investigated aspirating smoke detectors that are emerging as adaptive fire detectors in logistics warehouses. Then, through fire simulation (FDS), logistics warehouse modeling was conducted to compare and analyze the detection speed of general smoke detectors and aspirating smoke detectors according to four stages of fire growth and three locations of fire in the logistics warehouse. Result: Growth speed in Slow-class fires and Mediumclass fires, the detection speed of aspirating smoke detectors was faster regardless of the location of the fire. However, in Fast-class fires and Ultra-Fast-class fires, it was confirmed that the detection speed of general smoke detectors was faster depending on the location of the fire. Conclusion: It was confirmed that the detection performance of the aspirating smoke detector decreased as the fire growth speed increased and the location of the fire occurred further than the receiver of the aspirating smoke detector. Therefore, even if an aspirating smoke detector is installed in a warehouse that stores combustibles with high fire growth rates, it is judged that an additional smoke detector is attached far away from the receiver of the general smoke detector to increase fire safety.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.358-360
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• 2022

Modern society is developing rapidly and technologies that provide convenience in living are developing day by day. On the other hand, the development of cyber attacks that threaten cybersecurity is developing faster, and it still adversely affects the industrial environment, and industrial damage is steadily occurring every year. Industrial security is an activity that safely protects major assets or technologies of companies and organizations from these attacks. Therefore, it is a situation that requires professional manpower for security. Currently, the manpower situation for security is staffed, but knowledge of the understanding and concept of industrial security jobs is insufficient. In other words, there is a lack of professional manpower for industrial security. It is the NCS that came out to solve this problem. NCS is the state standardized ability (knowledge, attitude, skills, etc.) necessary to perform duties in the industrial field. NCS can systematically design the curriculum using NCS as well as help in hiring personnel, and NCS can be applied to the national qualification system. However, in the field of industrial security, NCS has not yet been developed and is still having difficulties in hiring personnel and curriculum. Although the NCS system in the field of industrial security has not been developed, this paper proposes the industrial security NCS to solve the problem of hiring professionals later and to help the field of industrial security NCS to be established later.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.2
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• pp.65-85
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• 2023

The use of TBM (Tunnel boring machine) has increased worldwide due to its performance together with the benefit of being safely and environmentally friendly compared to conventional tunneling. In particular, EPB (Earth Pressure Balanced) TBM is widely used because it can be applied to various grounds compared to Open TBM. Also EPB TBM has a simple mechanical structure and advantages in cost, requires less ground area than Slurry TBM. EPB TBM has advantages in soft ground, and more importantly, can extend its applicability by use of appropriate soil conditioning, which improves mechanical and hydrological properties of excavated soil and increases the excavation performance of EPB TBM. Various studies suggested the proper mixing ratio and injection ratio, but almost they are limited to laboratory test under atmospheric pressure such as slump test. Actual field conditions may differ depending on the ground and mechanical condition. In this study, first the amount of used soil conditioning used in the field with various grounds from hard rock to soft ground was estimated through laboratory tests and compared with the estimate in design stage. And also it was compared with the amount used during actual excavation. In addition, experience of soil conditioning for the problems of cutter head clogging and groundwater inrush that occurred during excavation is discussed. Finally, lesson learned for the use of soil conditioning in difficult ground condition such as mixed ground are reviewed.

• Journal of the Korean Geotechnical Society
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• v.39 no.4
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• pp.31-44
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• 2023

A base expansion micropile was developed to improve the bearing capacity of the micropile, which bears a simple device installed at the pile base. Under an axial load, this base expansion structure radially expands at the pile tip and attaches itself around ground, compressing the boring wall in the construction stage. In this study, conventional and base expansion micropiles were constructed in the weathered rock where micropiles are commonly installed. Further, field load tests were conducted to verify the bearing capacity enhancement effect. From the load test results, it was revealed that the shaft resistance of base expansion micropiles was about 12% higher than that of conventional micropiles. The load transfer analysis results also showed that compared to conventional micropiles, the unit skin friction and unit end bearing of base expansion micropiles were 15.4% and 315.1% higher, respectively, in the bearing zone of the micropile.

• Korean Journal of Construction Engineering and Management
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• v.24 no.2
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• pp.24-36
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• 2023

OSC is drawing attention to supplement limitations such as productivity problems and on-site safety and quality problems of existing on-site labor-oriented construction production methods. In order to activate the introduction and use of OSC in the domestic construction market, it is important to innovate the technology applied to each stage of OSC process (design and engineering, factory manufacturing, site assembly, and maintenance), but it is also necessary to develop a project management method suitable for OSC method. However, research related to OSC currently being conducted in Korea is mainly in terms of related technology development, and research on deriving project management measures for the success of OSC projects is insufficient. Therefore, it is time for research on deriving a project management plan based on the core success factors of the OSC project. Therefore, by conducting importance-performance analysis on 69 OSC critical success factors derived from the previous study, the study was conducted to derive key improvement factors for OSC introduction and utilization improvement and to provide implications for this. The results of this study are expected to have useful implications for the R&D planning and policy-making process for OSC activation in the future.

• Journal of the Korean Geotechnical Society
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• v.22 no.11
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• pp.123-131
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• 2006

Liquefaction-induced lateral spreading has been the most extensive damage to pile foundations during earthquakes. Several cases of pile failures were reported despite the fact that a large margin of safety factor was employed in their design. In this study, 1-g shaking table tests were performed in order to analyze the failure behavior of piles embedded in liquefied soil deposits by buckling instability. As a result, it can be concluded that the pile subjected to excessive axial loads $(near\;P_{cr})$ can fail easily by buckling instability during liquefaction. When lateral spreading took place in sloping grounds, it was found that lateral loading due to lateral spreading increased lateral deflection of pile and reduced the buckling load. In addition, from the buckling shape of pile, difference between Euler's buckling and pile buckling vat observed. In the case of pile buckling, hinge formed at the middle point of the pile, not at the bottom. And in sloping grounds, location of hinge formation got lower compared with level ground because of the soil movements.

• Journal of the Korean Geotechnical Society
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• v.26 no.5
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• pp.37-48
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• 2010

In this study, the seepage flow monitoring method by the hydraulic head loss rate was developed for the purpose of application to offshore construction site enclosed by cofferdams in which seepage force varies periodically. The amount of the hydraulic head loss rate newly defined in this graph was in a range between 0 and 1. The zero of the rate means the existence of flow with no seepage resistance. The 1 of the rate means no seepage flow through the ground. The closer to 1 the coefficient of determinant in the hydraulic head loss graph is, the more the ground through which seepage water flows is stable. The closer to 0 the coefficient of determinant in the hydraulic head loss graph is, the more the ground through which seepage water flows was unstable and the higher the possibilities of existence of empty space or of occurrence of piping on the seepage flow pass in the ground is. The hydraulic head loss graph makes it possible to monitor sensitively the situation of seepage flow state, and the graph helps to understand easily the seepage flow state at the specific section on the whole cofferdam.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.2
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• pp.113-120
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• 2023

This paper introduces a simulation method for the collision between roadblocks and vehicles using LS-DYNA. The need to evaluate the performance of anti-ram barriers to prepare for vehicle impact has increased since vehicle impact threats have been included as a design criterion for nuclear power plants. Anti-ram barriers are typically certified for their performance through collision experiments. However, because Koreas has no performance testing facilities for anti-ram barriers, their performance can only be verified through simulations. LS-DYNA is a specialized program for collision simulation. Various organizations, including NCAC, distributes numerical models that have been validated for their accuracy with collision tests. In this study, we constructed a finite element model of the most critical vehicle barrier module and simulated collision between roadblocks and vehicles. The calculated results were verified by applying the validation criteria for vehicle safety facility collision simulations of NCHRP 179.