• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.83-85
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• 2011

This study investigated the results of insulation heat curing method using double layer bubble sheet in concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that concrete was protected from early freezing by remaining between 7℃ and 3℃ even in case outside temperature drops -7℃ below zero until the 3d day from piling. The insulation heat preservation curing method using the double bubble sheet applied in this field prevented early freezing owing to stable curing temperature management, deterring concrete strength development delay at low temperature, and obtained the needed strength. Also, it was proven that the method is highly effective and economic for cold weather concrete quality maintenance through curing cost reduction like construction period shortening and labor cost reduction, etc by reducing the process of temporary equipment installation and disassembling.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.739-743
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• 2004

The Grid VO(Virtual Organization) is temporary VO where gather indivisual, authority, or system resource, differ from previous VO concept that controled by internal principal and policy set. It have many problems in case of indivisuals, authorities, or system resources that became member of some Grid VO at same time and combination followed changing condition of system resource for building Grid VO. This paper propose lightweighted Grid VO authentication system based on XML security to solve the authentication of the problems occuring in building Grid VO. In this paper, Grid VO authentication system is including Grid VO authentication module that is intermediate management system in PKI to previous authentication service structure and provide effective authentication service to Grid VO.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.25-28
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• 2009

This study investigated the results of insulation heat curing method using double layer bubble sheet in slab concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that slab concrete was protected from early freezing by remaining between 5 and $l0^{\circ}C$ even in case outside temperature drops $-11^{\circ}C$ below zero until the 4nd day from piling. The insulation heat preservation curing method using the double bubble sheet applied in this field prevented early freezing owing to stable curing temperature management, deterring concrete strength development delay at low temperature, and obtained the needed strength. Also, it was proven that the method is highly effective and economic for cold weather concrete quality maintenance through curing cost reduction like construction period shortening and labor cost reduction, etc by reducing the process of temporary equipment installation and disassembling.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.79-80
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• 2022

In December 2017, a fire at the Jecheon Sports Center caused 29 deaths and 40 injuries, and about 2 billion won in property damage. It is a facility used by unspecified people as a publicly used establishment with a piloti structure. The damage was expanded due to the ignition of combustible exterior materials, Lack of fire protection in horizontal and vertical penetrations. Although legislation has improved since the fire, it is not retroactively applied, increasing the risk of fire in existing buildings. Accordingly, it is necessary to examine the case of the Jecheon Sports Center fire and draw out the problems. In this study, the fire simulation results and the Jecheon Sports Center fire are comparatively analyzed and used as basic data for fire reduction measures in publicly used establishment. As a result of the fire simulation drive, in the case of the second floor, the room temperature exceeded the human life safety standard of 60 ℃ after about 700 seconds had passed. In the case of three floor, it is predicted that the indoor temperature will exceed about 350 ℃. and temporary complexation will occur in the indoor combustibles.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.96-97
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• 2018

Facilities used by senior citizens, infants, and disabled people have characteristics that make it difficult to escape on their own or require a lot of evacuation time. Therefore, to ensure safety in case of fire, clear measures for securing safety of facilities, fire response methods, and training are required in accordance with the regulations. In case of postnatal care center facilities, newborn babies and mothers reside 24 hours a day, and as they are located in high-rise and multi-use facilities, measures for fire safety are necessary, but the domestic manual lacks. Accordingly, a field survey for security of the manual revealed that the establishment of awareness and facilities on temporary waiting areas and smoke control, which are easy for evacuation and fire safety, was a problem.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.4
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• pp.866-875
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• 1994

The problem of a rigid rod sliding on a rough horizontal surface in the plane is analyzed, which is commonly cited as an example of the inconsistency of rigid body frictional mechanics. The inconsistency is demonstrated by analyzing the normal reaction force at the contact point with the surface, and the concept of tangential collision is derived to resolve the inconsistency. Using the Poisson's hypothesis for the coefficient of restitution and Coulomb's law for the friction, the general methodology for solving the tangential collision is presented. The problem of the inconsistency generated in the sliding rod is completely resolved, building the concept of the tangential collision and adopting the theory of frictional impact. The result presented in this paper will obviate a generic obstacle to the development of simulation packages for planar rigid body mechanical systems with temporary contacts, and planning efficient motion strategies for robot manipulators.

• Journal of the Korean housing association
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• v.21 no.4
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• pp.121-128
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• 2010

Many business enterprises in domestic housing industry are focusing on the development of environment friendly apartment complex to strengthen the competitiveness by upgrading their company's image through differentiation of the qualities and satisfying the customer's needs. Many apartment complex have achieved temporary or real certification by green building certification system, but there weren't enough studies on how much residents are satisfied by their certified complex. In this study, we want to clarify the factors of resident's satisfaction level in certified environment friendly complex by comparing the social and economical characteristics of resident. For this study, we chose and compare 4 environment friendly apartment complex considered to be built by the best environmental way in metropolitan area, and 4 other apartment complex which are also considered to be similar in terms of the condition of location and period of stay.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.521-532
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• 2008

Supporting system design and construction management for the soft and hard rock layers with fractured zones are very important theme for the safety of temporary retaining wall, surrounding ground and structures in the urban deep excavation for the construction of subway, railway, building etc. The prevailing design method of supporting system for the soft and hard rock layers in the deep excavation is mostly carrying out by simplification without proper consideration for the characteristic of rock discontinuities. Therefore the behaviors of rock discontinuities and fractured zones dominate the whole safety of excavation work in the real construction stage, serious disaster due to the failure of temporary retaining wall can be induced in the case of developing large deformations in the ground and large axial forces in the supporting system. This paper introduces examples of deep excavation where the soft and hard rock layers with fractured zones were designed to be supported by shotcrete and rock bolt, deformations of corresponding ground and supporting systems in the construction period and increments of axial force in the upper earth anchors and strut due to the these deformations were investigated through detailed analysis of measurement data, the results were so used for the management of consecutive construction that led to the safe and economical completion of excavation work. The effort of this article aims to improve and develop the technique of design and construction in the coming projects having similar ground condition and supporting method.

• Journal of the Society of Disaster Information
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• v.14 no.3
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• pp.315-324
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• 2018

Purpose: This paper propose a temporary indoor positioning scheme with devices of internet of things (IoT) for disastrous situations in places without the infrastructure of networks. Method: The proposed scheme is based on the weighted centroid localization scheme that can estimate the position of a target with simple computation. Results: It also is implemented with the IoT devices at the underground parking lot, where the network is not installed, of general office building. According to the experiment results, the positioning error was around 10m without a priori calibration process at $82.5m{\times}56.4m$ underground space. Conclusion: The proposed scheme can be deployed many places without the infrastructure of networks, such as parking lots, warehouses, factory, etc.

• Journal of The Korea Institute of Healthcare Architecture
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• v.29 no.4
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• pp.69-77
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• 2023

Purpose: During the COVID-19 pandemic, there have been many cases of converting regular hospital wards into temporary negative pressure isolation wards. The purpose of this study is to evaluate the minimum airflow differences that satisfies the pressure difference criteria(-2.5 Pa) according to airtightness of switching type wards, in preparation for utilization of aging regular wards as negative pressure isolation wards. Methods: Visual inspection and field measurements were conducted using blower door to evaluate airtightness of 5 hospital wards. CONTAM simulation was used to assess the airflow differences when pressure difference between the corridor and wards met the criteria at various levels of airtightness. Results: The ACH₅₀ of evaluated wards ranged from 19.3 to 50.1 h^-1 with an average of 37.0 h^-1, indicating more than four times leakier than other building types. The minimum airflow differences increased as the airtightness of the wards decreased and the size of the wards increased. Implications: When operating rapidly converted negative pressure isolation wards, understanding airtightness is crucial for determining the minimum airflow differences to maintain the pressure differences. The analysis of this study suggests that improving the airtightness of aging rooms is essential and the minimum airflow differences should be suggested considering both the airtightness and size of rooms.