• Journal of the Society of Naval Architects of Korea
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• v.57 no.2
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• pp.70-79
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• 2020

The offshore installation units may be subjected to various accidental loads such as collision from supply vessels, impact from dropped objects, blast load from gas explosion and thermal load from fire. This paper deals with the design and strength evaluation method of the stiffened plate structures in response to a blast load caused by a gas explosion accident. It is a comprehensive review of various items used in actual project such as the size and type of the explosive loads, general design procedure/concept and analysis method. The structural analyses using simple analysis methods based on SDOF model and nonlinear finite element analysis are applied to the particular FPSO project. Also validation studies on the design guidance given by simple analysis method based on SDOF model have also considered several items such as backpressure effects, material behavior and duration time of the overpressure. A good correlation between the prediction made by simple analysis method based on SDOF model and nonlinear finite element analysis can be generally obtained up to the elastic limit.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.84-96
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• 2022

In the worst case, a temporary ignition source (also known as transient combustibles) between two electrical panels can damage both panels. Mitigation strategies for electrical panel fires were previously developed using fire modeling and risk analysis. However, since they do not comply with deterministic fire protection requirements, it is necessary to analyze the boundary values at which combustibles may damage targets depending on various factors. In the present study, a sensitivity analysis of input variables related to the damage threshold of two electrical panels was performed for dimensionless geometry using a Fire Dynamics Simulator (FDS). A new methodology using a damage evaluation map was developed to assess the damage of the electrical panel. The input variables were the distance between the electrical panels, the vertical height of the fuel, the size of the fire, the wind speed and the wind direction. The heat flux was determined to increase as the vertical distance between the fuel and the panel decreased, and the largest heat flux was predicted when the vertical separation distance divided by one half flame length was 0.3-0.5. As the distance between the panels increases, the heat flux decreases according to the power law, and damage can be avoided when the distance between the fuel and the panel is twice the length of the panel. When the wind direction is east and south, to avoid damage to the electrical panel the distance must be increased by 1.5 times compared to no wind. The present scale model can be applied to any configuration where combustibles are located between two electrical panels, and can provide useful guidance for the design of redundant electrical panels.

• Earthquakes and Structures
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• v.25 no.1
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• pp.15-26
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• 2023

It is of great importance to assess the residual displacement demand in the performance-based seismic design. In this paper, a hybrid deep learning model for predicting the residual displacement spectra under near-fault (NF) ground motions is proposed by combining the long short-term memory network (LSTM) and back-propagation (BP) network. The model is featured by its capacity of predicting the residual displacement spectrum under a given NF ground motion while considering the effects of structural parameters. To construct this model, 315 natural and artificial NF ground motions were employed to compute the residual displacement spectra through elastoplastic time history analysis considering different structural parameters. Based on the resulted dataset with a total of 9,450 samples, the proposed model was finally trained and tested. The results show that the proposed model has a satisfactory accuracy as well as a high efficiency in predicting residual displacement spectra under given NF ground motions while considering the impacts of structural parameters.

• Progress in Superconductivity and Cryogenics
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• v.11 no.2
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• pp.25-28
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• 2009

A 154kV class high-temperature superconducting (HTS) power cable system is developing in Korea. For insulation design of this cable, it is important that study on cryogenic electrical insulation design to develop the cold dielectric type HTS cable because the cable is operated under the high voltage environment in cryogenic temperature. Therefore, this paper describes a design method for the electrical insulation layer of the cold dielectric type HTS cable adopting the partial discharge-free design under ac stress, based on the experimental results such a ac breakdown strength, partial discharge inception stress, $V_{ac}$-t characteristics, $V_{imp}$-n characteristics, and impulse breakdown strength of liquid nitrogen/laminated polypropylene paper (LPP) composite insulation system in which the mini-model cable is immersed into pressurized liquid nitrogen.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.11
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• pp.861-869
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• 2015

In this study, wall to bed heat transfer and hydrodynamic characteristics in a conical fluidized bed combustor was investigated using computational fluid dynamics method. A two-fluid Eulerian-Eulerian model was used with applying the kinetic theory for granular flow(KTGF). The effects of the two drag models, Gidaspow and the Syamlal-O'Brien model, different inlet velocities($1.4U_{mf}{\sim}4U_{mf}$) and different particle sizes on the hydrodynamics and heat transfer were studied. The results showed that the hydrodynamic characteristics such as bed expansion ratio and pressure drop were not affected significantly by the drag models. But the heat transfer coefficient was different for the two drag models, especially at lower gas inlet velocities and small particle sizes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.2
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• pp.334-337
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• 2021

Recently, the necessity of rapid response to social problems such as disasters and quarantine arising from the complex and diverse social structures has emerged. As the number of large buildings increases, large-scale human damage is expected in the event of a disaster such as fire. To solve this problem, efficient control must be achieved through interfacing with various equipment and facilities installed inside the building. In this paper, we intend to study the interface method for various facilities in the building for efficient control. In detail, the facility standard model is defined by examining the status and specification of building. In addition, we intend to design and propose a standard facility communication data frame to support the protocol applicable to this model.

• Fire Science and Engineering
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• v.23 no.4
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• pp.145-153
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• 2009

We are generally applicate smoke control only vestibule about special escape staircase, it is one of some smoke control model of NFSC 501A. But there are some point at issue in this system. The smoke control system on supervision field of writer is smoke control only vestibule same as the other resemble field. Writer studied in the concrete to find a solution at this issue, and derived a conclusion the most reasonable system on the field is "same time smoke control for staircase and vestibule" by the engineering analysis considering stack effect.

• Fire Science and Engineering
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• v.25 no.5
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• pp.32-38
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• 2011

Amphibious possible, and good fuel economy, so as leisure and transport has increased the use of hovercraft. Fire started in Korea, the prevalence is increasing in demand as the trend has been increasing steadily. In this paper, the hovercraft's forward and backward direction can be controlled in order to free the reverse bucket control system was developed. Control due to development by promoting the flow of air and turn right, turn left and easy to reverse the life-saving and stable at high speed, etc. has made possible the operation of hovercraft. The controller for the stability and fast response Fuzzy-PID method was used. To prove the validity of the proposed controller in Matlab simulation and the actual delivery at the firehouse, built into a model for the demonstration test was performed.

• Journal of the Korean Institute of Educational Facilities
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• v.24 no.2
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• pp.3-10
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• 2017

This study compared evacuation effectiveness between the conventional school auditorium plan and a suggested hypothetical plan that was generated by a mathematical model, which is commonly applied in the field of industrial engineering. Recent school buildings became much more complicated in floor planning due to new social needs and modern curriculum than the old days. Nevertheless, architect's approach to floor composition in terms of fire emergency evacuation planning, still has no relation to optimized effective but relies more on an conventional school planning. Therefore, since school buildings are much more likely to be exposed to any fire related events than any other building types, emergency exit effectiveness based on spatial composition has to be seriously evaluated with a scientific method. The algorithm, which acquires the number of persons in each spatial type(node) per floor and the minimum physical distance between spatial types(arc), can propose the most optimized spatial layout per floor regarding emergency evacuation event. Consequently, this study evaluated school's fire exit effectiveness focusing on auditorium area with the scientific tool and suggested the most reliable spatial layout regarding possibile emergency evacuation event.

• Journal of the Korean Institute of Educational Facilities
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• v.23 no.3
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• pp.3-10
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• 2016

This study compared evacuation effectiveness between the conventional school floor plan and a suggested hypothetical floor plan that was generated by a mathematical model that is commonly applied in the field of industrial engineering. Recent school buildings became much more complicated in floor planning due to the new educational system and modern curriculum than the old days. Nevertheless, architect's approach to floor composition in terms of fire emergency evacuation planning, still has no relation to optimized effective but relies more on a conventional school planning. Therefore, since elementary school buildings are much more likely to be exposed to any fire related events than middle school or high-school, emergency exit effectiveness based on spatial composition has to be seriously evaluated with a scientific method. The algorithm, which acquires the number of persons in each spatial type (node) per floor and the minimum physical distance between spatial types (arc), can propose the most optimized spatial compositing per floor regarding emergency evacuation event. Consequently, this study evaluated elementary school's fire exit effectiveness with the scientific tool and suggested the most reliable spatial composition per floor regarding possibile emergency evacuation event.