• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.40-46
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• 2024

Purpose: In this study, in order to ensure the evacuation safety of plant facilities, we analyze the relationship between the height of smoke removal boundary walls, the presence or absence of smoke removal equipment, and evacuation safety. Method: Using fire and evacuation simulations, evacuation safety was analyzed through changes in the height of the smoke removal boundary wall, air supply volume and exhaust volume according to vertical dista. Result: In the case of visible drawings, if only 0.6m of boundary wall is used, the time below 5m reaches the shortest, and 1.2m of boundary width is 20% longer than when using smoke removal facilities. In the case of temperature, 1.2m is 20% longer than 0.6m when only the boundary width is used without smoke removal facilities. Conclusion: It was found that increasing the length of the smoke removal boundary wall could affect visibility, and installing a smoke removal facility would affect temperature. Therefore, it is determined that an appropriate smoke removal plan and smoke removal equipment should be installed in consideration of the process characteristics.

• Journal of the Korean Society of Visualization
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• v.4 no.2
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• pp.51-58
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• 2006

A boundary layer visualization was carried out in order to investigate the influence of Reynolds number on an oscillating airfoil. An NACA 0012 airfoil is sinusoidally pitched at the quarter chord point with oscillation amplitude of ${\pm}6^{\circ}$. A smoke-wire technique was employed to visualize the boundary layer and the near-wake. The freestream velocities are 1.98, 2.83 and 4.03m/s and corresponding chord Reynolds numbers are $2.3{\times}10^4,\;3.3{\times}10^4$, and $4.8{\times}10^4$, respectively. As the reduced frequency of K=0.1 is fixed, the corresponding frequency of an airfoil was adjusted in each case. The results reveal that the point at which the shear stress in an unsteady boundary layer separation disappears does not correspond with the position of the breakdown of the boundary layer, and that the breakdown of the boundary layer occurs further downstream.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.83-84
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• 2022

In Korea, smoke control measures through NFSC 501 are proposed to reduce human casualties caused by smoke in the event of a fire. However, as a result of investigating and analyzing domestic and foreign standards, it was found that domestic regulations do not set fire source, but simply set smoke emissions by floor area or height of smoke boundary. Foreign regulations set fire source. Therefore, it is judged that it is necessary to review whether the current domestic regulations can be applied in the event of an actual building fire. So, this paper aims to identify the differences in domestic and foreign standards through investigation and analysis of related standards for fire zone smoke control system in each country and use them as basic data to improve the performance of zone smoke control system.

• The KIPS Transactions:PartB
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• v.16B no.4
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• pp.271-280
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• 2009

In this paper, we propose a smoke detection method using region growing method in outdoor video sequences. Our proposed method is composed of three steps; the initial change area detection step, the boundary finding and expanding step, and the smoke classification step. In the first step, we use a background subtraction to detect changed areas in the current input frame against the background image. In difference images of the background subtraction, we calculate a binary image using a threshold value and apply morphology operations to the binary image to remove noises. In the second step, we find boundaries of the changed areas using labeling algorithm and expand the boundaries to their neighbors using the region growing algorithm. In the final step, ellipses of the boundaries are estimated using moments. We classify whether the boundary is smoke by using the temporal information.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.4
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• pp.389-400
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• 2003

In order to recommend the mechanical smoke exhaust operation mode, Subway Environmental Simulation (SES) is used to predict the airflow of the inlet and outlet tunnel for the subway station. Fire Dynamic Simulation (FDS) is used the SES's velocity boundary conditions to clarity the smoke exhaust effectiveness by the variations with mechnical ventilation system. We compared each 6 types of smoke exhaust systems for the result of smoke density and temperature distributions for 1.5m height from the subway station base in order to clarify the safety evaluation for the heat and smoke exhaust on subway fire.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.22-28
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• 2021

This is a basic study on the development of deep learning-based algorithms to detect smoke before the smoke detector operates in the event of a ship fire, analyze and utilize the detected data, and support fire suppression and evacuation activities by predicting the spread of smoke before it spreads to remote areas. Proposed algorithms were reviewed in accordance with the following procedures. As a first step, smoke images obtained through fire simulation were applied to the YOLO (You Only Look Once) model, which is a deep learning-based object detection algorithm. The mean average precision (mAP) of the trained YOLO model was measured to be 98.71%, and smoke was detected at a processing speed of 9 frames per second (FPS). The second step was to estimate the spread of smoke using the coordinates of the boundary box, from which was utilized to extract the smoke geometry from YOLO. This smoke geometry was then applied to the time series prediction algorithm, long short-term memory (LSTM). As a result, smoke spread data obtained from the coordinates of the boundary box between the estimated fire occurrence and 30 s were entered into the LSTM learning model to predict smoke spread data from 31 s to 90 s in the smoke image of a fast fire obtained from fire simulation. The average square root error between the estimated spread of smoke and its predicted value was 2.74.

• Fire Science and Engineering
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• v.20 no.3 s.63
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• pp.9-14
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• 2006

In this study boundary velocity which is one of the important boundary conditions for numerical simulation for subway station on fire are experimentally obtained. The tests were conducted according to its operating mode of the ventilation systems in the platform: smoke extraction ventilation mode in occurrence of fire and normal ventilation mode for air conditioning. Velocities are measured at various points on the platform. To examine smoke extraction and air supply capacity in the platform level, air velocities were checked on opening vents. Numerical analysis under normal ventilation mode without fire is conducted by using measured boundary conditions, and the numerical results are compared with the measured velocities on the platform.

• Journal of Preventive Medicine and Public Health
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• v.52 no.6
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• pp.427-432
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• 2019

Objectives: In Indonesia, 61 million adults smoked in 2018, and 59 million were exposed to secondhand smoke at offices or restaurants in 2011. The Presidential Decree 109/2012 encouraged local governments to implement a smoke-free policy (SFP), and the city of Jayapura enacted a local bill (1/2015) to that effect in 2015. This study aimed to evaluate compliance with this bill and to explore challenges in implementing it. Methods: We conducted a mixed-methods study. Quantitatively, we assessed compliance of facilities with 6 criteria (per the bill): the presence of signage, the lack of smoking activity, the lack of sale of tobacco, the lack of tobacco advertisements, the lack of cigarette smoke, and the lack of ashtrays. We surveyed 192 facilities, including health facilities, educational facilities, places of worship, government offices, and indoor and outdoor public facilities. Qualitatively, we explored challenges in implementation by interviewing 19 informants (government officers, students, and community members). Results: The rate of compliance with all 6 criteria was 17% overall, ranging from 0% at outdoor public facilities to 50% at health facilities. Spatial patterning was absent, as shown by similar compliance rates for SFP facilities within a 1-km boundary around the provincial and city health offices compared to those outside the boundary. Implementation challenges included (1) a limited budget for enforcement, (2) a lack of support from local non-governmental organizations and universities, (3) a lack of public awareness at the facilities themselves, and (4) a lack of examples set by local leaders. Conclusions: Overall compliance was low in Jayapura due to many challenges. This information provides lessons regarding tobacco control policy in underdeveloped areas far from the central government.

• Fire Science and Engineering
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• v.21 no.1 s.65
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• pp.1-6
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• 2007

This paper investigated the fire and smoke behavior in the compounded multiplex theater using FDS with various spacial and boundary conditions to ensure the fire safety of the multiplex. The results showed that more rapid temperature increase and smoke can be induced near the exit door for the lower fire load duo to the horizontal smoke movement. The overuse of fire resistants can generate more smoke while delaying combustion rate, which can give adverse effect to the evacuation. The mal-function of the exhaust fan would obstruct smoke exhaust but also retard the function of sprinkler head.

• Fire Science and Engineering
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• v.17 no.2
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• pp.62-69
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• 2003

The smoke control system in subway platform is not only using for smoke exhaust facility but also using ventilation system. For this reason, smoke vent effectiveness is depending on its position, ventilating volume capacity and the vent method. In this study, the passenger's evacuation time was calculated for the case of fire on sloped subway train vehicle in subway platform. In order to recommend the mechanical smoke exhaust operation mode, SES (Subway Environmental Simulation) was used to predict the airflow of the inlet and outlet tunnel for the subway station. Fire dynamics Simulator(FDS) was used the SES's velocity boundary conditions to calculate the smoke density and temperature under the condition of fire on stopped subway train vehicle at the platform. We compared smoke density and temperature distributions for each 6 types of smoke exhaust systems to clarify the characteristics of smoke and hot air exhaust effectiveness from the result of fire simulation.