• Journal of the Korean Society of Safety
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• v.19 no.1
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• pp.49-55
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• 2004

This study presents an analysis of comparison of P-type fire detection system with fuzzy logic-applied fire detection system. The fuzzy logic-applied fire detection system has input variables obtained by fire experiment of small scale with K-type temperature sensor and optical smoke sensor. And the antecedent part of fuzzy rules consists of temperature and smoke density, and the consequent part consists of fire probability. Also triangular fuzzy membership function is used for input variables and fuzzy rules. To calculate the final fire probability a centroid method is introduced. A fire experiment is conducted with controlling wood crib layer, cigarette to simulate actual fire and false alarm situation. The results show that peak fire probability is 25[%] for non-fire and is more than 80[%] for fire situation, respectively. The fuzzy logic-applied fire detection system suggested here is able to distinguish fire situation and non-fire situation very precisely.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.235-236
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• 2022

In the present study, the effect of horizontal vent position on fire phenomena in the enclosure with vertical and horizontal vents was examined using numerical simulation. Case 1 indicates the condition that the horizontal vent is in the center of the ceiling. Case 3 indicates the condition that the horizontal vent is far away from the vertical vent. Case 2 indicates the condition that the horizontal vent is installed between Case 1 and Case 3. The temperature distribution, smoke layer temperature, velocity distribution, and mass flow rate of horizontal vent flow were analyzed. In Case 2, the temperatures were lowest and the mass flow rate through the horizontal vent was largest. This is because the flame is inclined by the inflow through the vertical vent. Hence, to determine the proper horizontal vent location for the high smoke ventilation performance, the inflow through the vertical vent and its effect on flame behavior should be considered.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.3
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• pp.342-348
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• 2014

Onshore great fires can normally be extinguished by firefighters using special firefighting equipment and its suitable method. However, offshore fires on the ships are to be extinguished by the crew without any supports from the onshore. Also, crews working on board are exposed to high risk of emergency evacuation due to the complicated structure arrangement of the ships and different accident types such as fire and ship collisions. As most of damage and loss of life in fire are associated with suffocation, shortening of evacuation time is an important factor to improve a survival rate. In this study, visibility in the accommodation area is analyzed by using the temperature and smoke flow which are obtained by the Fire Dynamic Simulator(FDS) as a Three-Dimensional Fire Analysis program to understand the survival rate of the crew upon the fire. The fire doors for most of ships are designed to close automatically when the fire alarm is activated. These automatic closing of the fire doors is a very effective system to delay the spread of flame and smoke flow for the unmanned spaces of the fire protected area. However, if the crew cannot escape within the estimated time, the crew inside the fire protected area will be damaged a lot. In this paper, the comparative analysis between the evacuations by using the fire door from the fire protected area and the suggested fire shielding structure in this study is carried out by the smoke flow rate and the temperature rise rate.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.6
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• pp.845-856
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• 2017

In the long railway tunnel, in order to secure safety in case of fire, it is required a emergency station. However, there is no standard or research results on smoke exhaust method and exhaust flow rate in emergency station, so it is necessary to study the smoke exhaust system for emergency station. In this study, we are created a numerical analysis model for emergency station where the evacuation cross passage connected to the service tunnel or the relative tunnel was installed at regular intervals (40 m intervals). And the fire analysis are carried out by varying the fire intensity (15, 30MW), the smoke exhaust method (only air supply, forced air supply and exhaust, forced air exhaust only), and the air flow rate (7, 14, $40m^3/s$). From the results of fire analysis, temperature and CO concentration are analyzed and ASET based on the limit temperature are compared at various condition. As a result, in the case with fire intensity of 15 MW, it is shown that a sufficiently safe evacuation environment can be ensured by applying forced air supply and exhaust method or forced air exhaust only method when the air flow rate is $7m^3/s$ above. In case of fire intensity of 30 MW, it is impossible to maintain the safety evacuation environment for more than 900 seconds when the exhaust air volume is below $14m^3/s$. And when the air flow rate is $40m^3/s$, the exhaust port is disposed at the side portion of the upper duct, which is most advantageous for securing the temperature-based safety.

• Fire Science and Engineering
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• v.28 no.1
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• pp.44-51
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• 2014

Smoke from fire is a mixture of combustion gases and particles which include micro-droplets formed from condensed organic vapors and carbonaceous agglomerates. The inhalation of smoke particles causes adverse health effects, and it is prerequisite for the hazard and risk analysis of the smoke particles to know how they behaviour in the respiratory tract. The characteristics of the absorption and adsorption of toxic gases and the amount and location of the particle deposition within the respiratory tract that determine the adverse health effects are related to the morphology and the size distribution of smoke particles. In the present work, as a preliminary study for the adverse health effects of smoke particles, the morphologies of the smoke particles from combustible materials were investigated for each fire stage: smouldering, well-ventilated flaming, small under-ventilated flaming, fully-developed under-ventilated fire. The steady-state tube furnace method given in ISO/TS 19700 was used for the generation of smoke particles. The fire stages were controlled by changing furnace temperature and equivalent ratio. The morphologies were analyzed by using Transmission Electron Microscope (Bio-TEM) by collecting the particles on TEM grids put on each stage of a cascade impactor.

• Journal of Korean Society of Forest Science
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• v.98 no.3
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• pp.290-296
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• 2009

In this study, we considered the combustion of the various herbs in youngdong areas such as festuca ovina, isodeon japonicus, oplismenus undulatifolius, pueraria thunbergiana, and cirsium japonicum var. ussuriense using the ignition temperature tester, cone calorimeter, smoke density chamber. We confirmed that the range of ignition temperature was $400{\sim}455^{\circ}C$ and the time to ignition and flameout were not recorded. The total heat release of isodeon japonicus was highest and the smoke release of festuca ovina was highest, and the yield of CO and $CO_2$ of pueraria thunbergiana, and cirsium japonicum var. ussuriense were highest among the samples. As a result, we concluded that isodeon japonicus will impact the fire intensity and fire spread and festuca ovina, pueraria thunbergiana, and cirsium japonicum var. ussuriense will influence the refuge.

• Korean Journal of Agricultural Science
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• v.37 no.3
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• pp.501-508
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• 2010

A swirl chamber type diesel engine attachable to 18 kW agricultural tractors was improved to reduce exhaust emissions. Compression ratio and throat area ratio of the combustion chamber were varied to determine optimum combustion conditions. Tests were composed of full load and 8-mode emission tests. Compression ratio was fixed as 21, but the swirl chamber volume was increased by 3.8%. Output power, torque, specific fuel consumption, exhaust gas temperature, and smoke level were not considerably different for compression ratios of 21.5 (reference condition) and 21 (test condition), while NOx, HC, CO and PM levels for the compression ratio of 21 were decreased by 11%, 46%, 28%, 11%, respectively, from those for the compression ratio of 21.5. The tests were also conducted with a compression ratio of 22 and 4.3% increased chamber volume. Output power, torque, exhaust gas temperature and smoke level were greater, while specific fuel consumption was less for the compression ratio of 22 than those for the compression ratio of 21.5. Increase of compression ratio decreased HC and CO levels by 24%, 39%, but increased NOx and PM levels by 24%, 39%. Based on these results, a compression ratio of 21 was selected as an optimum value. Then, full load tests with the selected compression ratio of 21 were carried out for different throat ratios of 1.0%, 1.1%, 1.2%. Output power and torque were greatest and smoke was lowest when throat area ratio was 1.1%, which satisfied the target values of specific fuel consumption (less than 272 g/$kW{\cdot}h$) and exhaust gas temperature (less than $550^{\circ}C$). Therefore, a throat area ratio of 1.1% was selected as an optimum value.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.2
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• pp.153-159
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• 2004

The purpose of this research is to investigate the performance of swirl combustion chamber diesel engine by changing the jet passage area, the depth and shape of the piston top cavity (main chamber). The performance of diesel engine with newly changed swirl combustion chamber was tested through the experimental conditions as engine speed, load and injection timing etc. The test results were compared and analyzed. And another purpose of this research is to make a new diesel engine that is satisfied fuel consumption and regulation value of exhaust gas. 1. The rate of fuel consumption was affected significantly by the jet passage area at the high speed and load than low speed and low load. The influence of jet passage large area was proven to decrease the rate of fuel consumption. 2. Smoke was affected significantly by the depth of the piston top cavity, but exhaust temperature and the rate of fuel consumption wasn't affected. The rate of fuel consumption was affected by changing injection timing. 3. The rate of fuel consumption, exhaust temperature and Smoke were affected significantly by the shape of the piston top cavity from rectangular to trapezoid. That is we have all high value. The exhaust smoke density and exhaust gas temperature depended sensitively on variation of the injection timing rather than the shape of the combustion chamber within the experimental conditions. 4. We made a new diesel engine that is satisfied design target values(sfc=190 g/hr, NOx + THC=6.0 g/KWh, PM=0.3 KWh), the rate of fuel consumption and emission standard etc., through changing injection timing at the maximum torque point and rated power point. Although we have a little high NOx value.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.3
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• pp.81-87
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• 2009

In this study, we have investigated the combustibility of five shrubs growing in Youngdong area such as Lindera obtusiloba, Lespedeza maximowiczii, Zanthoxylum piperitum, Zanthoxylum schinifolium, and Corylus heterophylla var. thunbergii using the ignition temperature tester, the cone calorimeter and the smoke density chamber in order to estimate the danger of a forest fire. The results showed that Lespedeza maximowiczii has the lowest ignition temperature, the fastest ignition time and the highest average release concentrations of CO and $CO_2$. Zanthoxylum piperitum and Zanthoxylum schinifolium showed the highest level in heat release and smoke release, respectively. Therefore, we have concluded that Lespedeza maximowiczii has the highest ignitibility, Zanthoxylum piperitum the most intensive fire spread and fire intensity, and Zanthoxylum schinifolium and Lespedeza maximowiczii most difficult to escape from a forest fire.

• Journal of the Korea Society for Simulation
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• v.19 no.2
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• pp.1-8
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• 2010

With recent development of computer hardware and 3D graphic technique, a lot of people have concern for something to express as the 3D graphic that look the real environment. Because the request of users have increased, the 3D simulation is developed and popularized in the many field. In this paper, we design and implement the simulation system that humans evacuate a building fires using the 3D graphic techniques. In this paper, we use the A* algorithm to humans have the artificial intelligence at evacuating a building fires, calculate the evacuation speed of each human considering temperature damage and smoke damage. In this paper, we applied the real building to demonstrate the effect of proposed evacuation simulation. Experimental results showed that the evacuation speed is affected by the temperature condition and the smoke density.