• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.1
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• pp.105-115
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• 2014

A numerical analysis on the smoke behavior and evacuee safety has been performed with computational fluid dynamics. The purpose of this study is to build computational processes for an evacuation and prevention of a fire disaster of a 3 km-length tunnel in Korea. To save computational cost, 1.5 km of the tunnel that can include a few cross-passing tunnels is considered. We are going to assess the fire safety in a road tunnel according to the smoke level, which consists of the smoke density and the height from the floor. The smoke density is obtained in detail from three-dimensional unsteady CFD analysis. To obtain proper temperature distributions on the tunnel wall, one-dimensional conduction equation is considered instead of an adiabatic wall boundary or a constant heat flux. The tunnel considered in this study equips the cross passing tunnels for evacuees every 250 m. The distance is critical in both safety and economy. The more cross passing tunnels, the more safe but the more expensive. Three different jet fan operations can be considered in this study; under- and over-critical velocities for normal traffic condition and 0-velocoty operation for the traffic congestion. The SE (smoke environment) level maps show a smoke environment and an evacuating behavior every moment.

• Journal of the Korean housing association
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• v.19 no.5
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• pp.103-110
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• 2008

The purpose of this study is to know how visual-field obstruction from fire smoke influences a resident's necessary time to reach fire escape and evacuation movement in a high-rise apartment housing. Generally, fire smoke not only gives visual-field obstruction and breath troubles to residents but interrupts their evacuation behavior. If a fire smoke layer is formed in the core department when evacuee enters at the evacuation staircase until, residents will be made to undergo a range of vision obstacle. In order to set a situation like that, participants wore eye bandage which had been made especially before the experiment. Also as a comparative standard, through no.1442 Japanese construction ministry notices about the building evacuation safety verification method, this study calculated smoke layer's dissent time and evacuation time. Then to compare with the former, the participants without an eye bandage joined a experiment once again. This study has understood how fire smoke effects on one's evacuation delay by analyzing residents' evacuation time to reach the staircase and movement route, however, in this study a toxic gas is not considered because it might threaten participants not to breathe.

• Journal of the Korean Society for Railway
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• v.12 no.1
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• pp.25-30
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• 2009

The present study deals with numerical investigation for smoke behavior in rescue station by using the commercial CFD code (FLUENT Ver 6.3). With the use of the MVHS(Modify Volumetric Heat Source) model modified from the original VHS(Volumetric Heat Source) model, a 10 MW mode was adopted for simulation and the MVHS model can describe the generation of product and the oxygen consumption at the stoichiometric state. In addition, the present simulation includes the species conservation equations for the materialization of heat source and the estimation of smoke movement. From the results, the smoke flows are moving along the ceiling because of thermal buoyancy force and as time goes, the smoke gradually moves downward at the vicinity of the entrance. Moreover, without using ventilation, it is found that the smoke flows no longer spread across the cross-passages because the pressure in the non-accident tunnel is higher than that in the accident tunnel.

• Fire Science and Engineering
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• v.15 no.2
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• pp.59-79
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• 2001

The paper proposes alternatives for fire safety in architectural planning through heat-smoke distribution related to openings so that we decrease casualty and property loss by fire and lay a great emphasis on building high-rise apartments with consideration of fire safety in Korea. An analysis program(HFA-Heat Fluid Analysis) is built to perform simultaneously numerical analysis and experimental analysis on rooms, units and buildings. In consequence, on the first, fire prevention methods are required to be set up related to openings for design rooms since the flow of heat and smoke is influenced by the type of openings in high-rise apartments. Second, the numerical analysis showed that different planning types cause to show differences in the spreading time of heat and smoke to design the units of high-rise apartments. On the third, each unit building showed different fire behavior depending on openings by numerical analysis and small scaled experiment on heat and smoke flow.

• Journal of the Korean Society of School Health
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• v.33 no.1
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• pp.10-18
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• 2020

Purpose: The purpose of this study was to investigate the effects of secondhand smoke on depression and suicidal ideation in adolescents. Methods: The study used the raw data of the Korea Youth Risk Behavior Web-based Survey (2018). Age, academic achievement, living with family, economic status, and stress were adjusted and the relationship between secondhand smoke and depression and suicidal thoughts was analyzed by gender. Results: The results showed that secondhand smoke had a significant effect on mental health of adolescents. Male students who experienced secondhand smoke at school and at public places had 1.41 times and 1.37 times higher depression rates, respectively. Female students who experienced secondhand smoke at home, school, and public places had 1.27 times, 1.35 times, and 1.39 times higher depression rates, respectively. Suicidal thoughts were 1.17 times and 1.22 times higher among male students who experienced secondhand smoke at school and at public places. Female students who experienced secondhand smoke at home, school, and public places had 1.12 times, 1.08 times, and 1.21 times more suicidal thoughts. Conclusion: Secondhand smoke has a significant effect on adolescent depression and suicidal thoughts. Therefore, efforts should be made to have institutional changes and increased awareness across the country, such as homes, schools, and communities, to prevent exposure to secondhand smoke.

• Research in Community and Public Health Nursing
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• v.11 no.1
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• pp.209-221
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• 2000

I began the study to identify the issues related to knowledge. attitude and behavior regarding smoking by sixth graders. which will ultimately lead to the development of a smoking prevention program that will not only help deter school-age children from smoking, but also make them aware of the more desirable behaviors and techniques for healthier life. The results are as follows: 1. Smoking Behavior: Of the focus group. 4.15% are current smokers and 18.23% are ever smokers. 2. Correlation between smoking knowledge and ever smoking: Ever smoking sample($11.10{\pm}3.66$) is less knowledge able than the never-smoking sample($12.17{\pm}3.95$), (t=3.23. p=.001). 3. Correlation between smoking attitude and ever smoking: Ever smoking sample($28.12{\pm}8.51$) was less desirable than the never-smoking sample($l2.17{\pm}3.95$). (t=8.24, p=.000). 4. Correlation between smoking Knowledge and smoking attitude: knowledge about smoking and attitude toward smoking are quantitatively correlated in such way that the more knowledgeable the child is about smoking. the more desirable the attitude toward smoking is(r=.17. p=.000). 5. Correlation between socio-anthropological characteristics and ever smoking: family . atmosphere($x^2$=16.49. p=.001), school life ($x^2$=l1.58, p= .003), grades in school( $x^2$=11.89. p=.003), gender($x^2$=8.97. p=.003). friends' gathering place($x^2$=13.19. p=.02), marital status of parents(p* =.03). and family's financial status($x^2$=6.71. p=.035). In addition, Correlation between somking-environmental characteristics and ever smoking: number of friends who smoke($x^2$=76.01. p=.001). information source for smoking($x^2$=48.03. p=.001), whether or not siblings smoke($x^2$=26.07, p=.001), whether or not female relatives smoke ( $x^2$= 15.65. p= .001), whether or not father smokes ($x^2$= 12.10. p= .007), errands to buy cigarettes for someone($x^2$=9.18. p=.010), and whether or not male relatives smoke ($x^2$=8.82. p=.35) 6. Results of the logistic analysis performed to identify the factors correlated to ever smoking show that: one point decrease in attitude score translates to 25.39 times' increase in ever smoking one person decrease in the number of friends who smoke translates to 0.66 times' decrease in ever smoking: the group where the father has quit smoking has 1.40 times more ever smoking than the group where the father does not smoke at all: and likewise, the group where the father currently smokes has 1.40 times more ever smoking than the group where the father has quit smoking. 7. The overall cause-and-effect relationship between the ever smoking and the related factors: attitude toward smoking caused ever smoking by -.43, smoking by friends, by .12, marital status of arents, by .05, school life. by .04, gender, by -.03, and smoking by father, by -.02. Knowledge about smoking (t=-1.67) did not cause significant effects on ever smoking.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.6
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• pp.451-462
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• 2011

The smoke control system plays the most important role in securing evacuation environment when a fire occurs in road tunnels. Smoke control methods in road tunnels are classified into two categories which are longitudinal ventilation system and transverse ventilation system. In this study it is intended to review the characteristics of smoke behavior by performing numerical analysis for calculating the optimal smoke exhaust air volume with scaled-model and simulation when a fire occurs in tunnels in which transverse ventilation is applied, and for obtaining the basic data required for the design of smoke exhaust systems by deriving optimal smoke exhaust operational conditions for various conditions. As a result of this study, when the critical velocity in the tunnel is 1.75 m/s and 2.5 m/s, the optimal smoke exhaust air volume has to be more than $173m^3/s$, $236m^3/s$ for the distance of the smoke moving which can limit the distance to 250 m. In addition, in case of uniform exhaust the generated smoke is effectively taken away if the two exhaust holes near the fire region are opened at the same time.

• Fire Science and Engineering
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• v.23 no.3
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• pp.79-84
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• 2009

The smoke control system plays the most important role in securing evacuation environment when a fire occurs in road tunnels. Smoke control methods in road tunnels are classified into two categories which are longitudinal ventilation system and transverse ventilation system. In this study it is intended to review the characteristics of smoke behavior by performing numerical analysis for calculating the optimal smoke exhaust air volume when a fire occurs in tunnels in which transverse ventilation is applied, and for obtaining the basic data required for the design of smoke exhaust systems by deriving optimal smoke exhaust operational conditions for various conditions. As a result of this study, when the critical velocity in the tunnel is 1.75m/s and 2.5m/s, the optimal smoke exhaust air volume has to be more than $173m^3/s$, $236m^3/s$ for the distance of the smoke moving which can limit the distance to 250m. In addition, in case of uniform exhaust the generated smoke is effectively taken away if the two exhaust holes near the fire region are opened at the same time.

• Journal of Korean Public Health Nursing
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• v.19 no.2
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• pp.305-315
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• 2005

Purpose: The purpose of this study was to investigate the relationships among depression, sleep patterns and health promoting behavior in female college students. Methods: The subjects of this study consisted of 350 college students. The data was collected through self-administered questionnaires from November to December of 2004. The data was analyzed via the SPSS computer program by using descriptive statistics, t-tests, ANOVA and Pearson's correlation coefficients. Results: There are significant differences and impacts on depression according to the amount of coffee consumed, the time spent on computer and the amount of smoke inhaled. Sleep patterns differ depending on one's college major, the time spent on computer, and the amount of smoke inhaled. Health promotion behavior was shown to be significantly different according to the living style, college major and how much TV was watched The mean scores for depression, sleep patterns, health promoting behavior were 1.45 (on a 3 points scale), 2.71 (on a 4 points scale), and 3.03 (on a 5 point scale), respectively. There was a significant positive correlation between sleep patterns and health promoting behavior, and there was negative correlation between depression and health promoting behavior, and between depression and sleep patterns in college students. Conclusion: The findings of this study give useful information to create further studies on intervention programs related to health promoting behavior for college female students.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.683-690
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• 2021

The ventilation system of the engine room of a ship is generally installed to supply the combustion air necessary for the internal combustion engine and to remove the heat source generated in the engine room, and it must satisfy the international standard (ISO 8861) for the design conditions and calculation standards for the ventilation of the ship engine room. The response delay of the ventilation system including the fire detector is affected by the airflow formed inside the area and the location of the fire detector. In this study, to improve the initial fire detection response speed of a fire detector installed on a fishing vessel and to maintain the sensitivity of the installed detector, the smoke behavior was simulated using the air flow field inside the engine room, the amount of combustion air in the internal combustion engine, and the internal pressure of the engine room as variables. Analysis of the simulation results showed that reducing the flow rate in the air flow field and increasing the vortex by reducing the internal pressure of the engine room and installing a smoke curtain would accelerate the rise of the ceiling of the smoke component and improve the smoke detector response speed and ventilation system.