• Fire Science and Engineering
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• v.33 no.1
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• pp.7-14
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• 2019

While wood pellets are often used as a fuel in thermoelectric power plants and firewood boilers, there is a risk of ignition temperature when strong wood pellets, which have a high calorific value, for prolonged periods of time. In this research study, the minimum auto ignition temperature and the ignition limitation temperature according to the change in flow rate depending on the size of the test vessel were calculated, and based on these temperatures, the apparent activation energy was calculated to predict the combustive properties of the material. The apparent activation energy was calculated to be 190.224 kJ/mol. The thicker the sample is storage in the vessel, the longer the ignition induction time was due to the increased difficulty in heat being transferred from the surface of the vessel to the middle section area of the vessel. For vessel of the same size, the higher the flow rate, the lower the auto ignition temperature was. It was also confirmed that increases in the size of the test vessel lowered the auto ignition temperature and increased the ignition induction time.

• Journal of the Society of Disaster Information
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• v.19 no.2
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• pp.280-291
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• 2023

Purpose: As fire accidents happen at the production and storage sites of superabsorbent polymers for convenience of daily life, an experimental study was conducted to secure basic data to establish practical preventive measures against them. Method: The sample container (20cm width × 20cm length) was made into a rectangular cuboid with the heights of 3cm, 5cm, 7cm, and 14cm, respectively, to allow access to the infinite flat plane. The front and back of the container were covered with a 300-mesh stainless steel mesh for one-dimensional heat transfer. The sample container was placed in the center of the thermostatic bath, which was heated to a predetermined temperature by setting the thermostat program in advance, and it was determined to be 'ignited' when the central temperature of the sample rose by more than 20℃ above the set temperature, and "unignited" when it was maintained at an approximate value of the set temperature. Result: The critical autoignition temperature was calculated to be 217.5℃ when the height of the sample container was 3 cm, 212.5℃ when it was 5 cm, 202.5℃ when it was 7cm, and 187.5℃ when it was 14cm. The ignition induction time to reach the maximum temperature was 34hours for 3cm, 76hours for 5cm, 143hours for 7cm, and 318hours for 14cm. Conclusion: ① As the size of the container increased, the autoignition temperature decreased and the induction time to reach the maximum temperature increased. ② An apparent activation energy was calculated to be 44.92kcal/mol, with a correlation of 96.93%.

• Journal of the Society of Disaster Information
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• v.19 no.2
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• pp.292-304
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• 2023

Purpose: This study was conducted to obtain experimental data for the establishment of preventive measures against fire, as large and small fire accidents occur at production and storage sites of superabsorbent polymers developed for the convenience of daily life. Method: The sample container was fixed at 0.2m in both length and width, and was shaped into a rectangular cuboid with heights of 3cm, 5cm, 7cm, and 14cm to access an infinite flat plane. The sample container was fixed in the center of a thermostatic bath that was heated to a predetermined temperature according to a preset temperature control program. If the central temperature of the sample rose more than 20℃ above the set temperature, it was determined to have 'ignited', and if it remained similar to the set temperature, it was determined to have 'unignited'. Result: The critical autoignition temperature was calculated to be 212.5℃ for a sample container with a height of 3cm, 202.5℃ for 5cm, 192.5℃ for 7cm, and 177.5℃ for 14cm. The ignition induction time to reach the highest temperature was approximately 42hours for 3cm, 91hours for 5cm, 151hours for 7cm, and 300hours for 14cm. Conclusion:① As the size of the sample container increased, the autoignition temperature decreased and the ignition induction time to reach the highest temperature increased. ② The apparent activation energy was calculated to be 39.30kcal/mol, with a correlation of 99.5%.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.225-227
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• 2011

최근 스마트폰 및 게임, 로봇, 어플리케이션 등 다양한 분야에서 음성 기반 채팅 시스템이 활용되고 있다. 하지만 그 성능은 아직 만족스럽지 못하다. 본 논문은 다양한 시스템 발화를 위해 문장의 내용어, 카테고리, 발화시간, 화자 정보 등을 이용하여 직전 발화와 현재 발화를 비교한다. 동일한 발화일 경우 해당 카테고리 내 다른 문장을 발화하여 발화의 다양성을 확보하고, 적용 카테고리가 아닐 경우 댓구를 이용하여 대화를 다른 주제로 유도한다. 실험 결과 중복 발화에 대해 다양한 응답을 확인 할 수 있었다.

• Korean Chemical Engineering Research
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• v.55 no.5
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• pp.623-628
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• 2017

Using wood pellets, which are used as fuel for thermal power generation plants, as test specimens, the minimum spontaneous ignition temperatures according to the size of the container for the test specimens were measured, and by applying the Frank-Kamenetskii theories on thermal energy to these temperatures, the danger factor of the materials were calculated by deriving the apparent activation energies. The results confirmed that the ignition threshold temperature decreased as the size of the container increased and that the spontaneous ignition energy was 37.83 kcal/mol. The results also confirmed that the larger the container for the test specimens was the time to arrive at the spontaneous ignition time and maximum temperature also increased.

• Fire Science and Engineering
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• v.17 no.4
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• pp.117-123
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• 2003

In this study; the ignition and heat release rate characteristics of rigid polyurethane foam were investigated in accordance with setchkin ignition tester and cone calorimeter which is using oxygen consumption principle. In the ignition temperature study; flash-ignition temperature was $383^{\circ}C$-$390^{\circ}C$, self-ignition temperature was$ 493^{\circ}C$∼495$^{\circ}C$. The self-ignition temperature of rigid polyurethane foam was about $100^{\circ}C$ higher than the flash-ignition temperature. In the cone calorimeter study, the time to ignition of rigid polyurethane foam was faster as the external heat flux increase. In the same heat flux level, the time to ignition was faster as the density of rigid polyurethane foam decrease. Also the heat release rate was the largest value at the heat flux of /$50 ㎾\m^2$ and had a tendency of increase as the heat flux level and density increase. In the standpoint of time to ignition and heat release rate, the fire performance of rigid polyurethane foam was influenced by the applied heat flux level and density and the flashover propensity classified by Petrella's proposal was high.

• Journal of the Korean Society of Safety
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• v.8 no.3
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• pp.44-49
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• 1993

The spontaneous ignition induction time and temperature distribution were observed by performing experiments for granulated activated carbon. As the results of the experiments at the same amplitude, the critical spontaneous ignition temperature was decreased with increase of the time period, while, the ignition induction time was increased with the increase of the time period. The critical spontaneous ignition temperature was decreased with the increase of the amplitude for the shorter period. The temperature distribution of the sample showed the highest around ignition-point at center of the vessel and after ignition the highest temperature was moved toward surface of the vessel.

• Phonetics and Speech Sciences
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• v.12 no.1
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• pp.19-31
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• 2020

The purpose of this study is to observe the realization of pause and breath groups from adult speakers and to examine how gender, generation, and tasks can affect this realization. For this purpose, we analyzed forty-eight male or female speakers. Their generation was divided into two groups: young, old. Task and gender affected both the realization of pause and breath groups. The length of the pause groups was longer in the read speech than in the spontaneous speech and female speech. On the other hand, the length of the breath group was longer in the spontaneous speech and the male speech. In the spontaneous speech, which requires planning, the speaker produced shorter length of pause group. The short sentence length of the reading material influenced the reason for which the length of the breath group was shorter in the reading speech. Gender difference resulted from difference in pause patterns between genders. In the case of the breath groups, the male speaker produced longer duration of pause than the female speaker did, which may be due to difference in lung capacity between genders. On the other hand, generation did not affect either the pause groups or the breath groups. The generation factor only influenced the number of syllables and the eojeols, which can be interpreted as the result of the difference in speech rate between generations.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2003.06a
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• pp.137-140
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• 2003

본 연구는 치매노인환자의 생활의 질을 향상시키기 위한 대화시스템의 개발에 목표를 둔다. 제안된 시스템은 주로 세 가지 모듈, 즉, 음성인식, 시간테이블에 의해 구분된 대화 데이터베이스의 자동검색, 그리고 간호사의 녹음음성에 의한 응답 등으로 구성되어 있다. 우선 치매환자가 요양시설에서 자주 발화하는 대화의 내용을 조사하고, 그들의 발화 음성을 인식하고 적절히 응답하도록 구성하였다. 시스템의 평가를 위해서 시스템이 도입되었을 때와 도입되지 않았을 때를 비교, 조사하였다. 시스템이 도입되지 않았을 때는 간호사가 자유로이 케어서비스를 행할 수 있도록 하였다. 비디오 촬영을 통해서 대상자의 행동 및 반응을 조사한 결과, 치매환자의 요구를 충족시키는데 있어서 대화 시스템이 간호사들보다 더 응답적이었다는 것을 알 수 있었다. 게다가, 제안된 시스템은 상호 대화에 있어서 환자가 더 많이 말하도록 유도함을 알 수 있었다.

• Journal of Digital Convergence
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• v.10 no.7
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• pp.141-152
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• 2012

The typical evacuation guidance system based on fire detectors, which is being widely used in theaters and large buildings, is often operated in an analog manner. In case of fire, it often causes the system to lose a wired line or wireless fire detection sensor, resulting in the difficulty of transmitting signals from a wired or wireless fire detection sensor to the main fire monitoring device. Accordingly, this paper has proposed the broadcasting system for disaster management, having an efficient evacuation guidance plan when a disaster occurs. The system reacts to an emergency situation along with fire alarm sirens in real time. We have implemented the above system by means of a simulation program that prints the evacuation guidance information (e.g., location and time of fire, and evacuation path) on an LCD located in a building through the fire sensor network in case of an emergency (e.g., actual fire). We have developed the simulation system by using mathematical algorithms, such as the optimal path search and the fire smoke diffusion algorithm. This simulation program considers the structure of a building and the location where the fire has initially occurred, applying it to the simulator.