• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.356-362
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• 2008

This study is intended to evaluate the characteristics of smoke spreading and the appropriateness of evacuation time extended by operation of smoke control system during fire within the underground space of the building structured in compliance with the smoke control system performance criteria from the local fire safety standard in Korea. As a preceding review of this study, the combustibles was categorized and identified their heat release rates. For validate the estimated values, modeling a single underground shop was carried out. And a numerical analysis both in case of smoke control system in operation and the system not in operation was carried out of underground space. From the viewpoint of securing the evacuation time, the results were compared in an attempt to assess the appropriateness of the fire safety criteria.

• Journal of Korea Technology Innovation Society
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• v.6 no.2
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• pp.213-227
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• 2003

초고속 인터넷 서비스는 사용자수의 증가와 더불어 고객의 다양한 욕구 즉 인터넷 방송, 주문형비디오(VOD)서비스, 원격교육, 고화질 TV 등 대용량의 멀티미디어 서비스에 대한 욕구가 폭발적으로 증가하고 있다. 이러한 욕구를 충족하기 위해서는 현재의 초고속 인터넷서비스로서는 속도에 대한 한계에 부딪치게 되어 통신사업자들은 새로운 기술 또는 여러 가지 기술적 대안들을 추구하고 있다. 2002년부터 시작하여 2003년 이후에는 멀티미디어 수요의 증가에 따라 ADSL을 대체하는 기술로 VDSL이 등장하여 매년 꾸준한 신규가입자 수요가 발생하고 있으나, 통신사업자들은 각각의 망 특성, 시장위치, 전략적 필요성 둥에 의해 상용화를 적극 검토,추진하고 있으나 각각 전개하는 방식은 조금씩 다르다. 따라서 본 연구에서는 통신사업자들의 가입자망 진화 전략에 대해 살펴 본 다음 Lot3n-Volterra Competition (LVC) 모델을 이용 ADSL 과 VDSL 두 기술간의 상호 경쟁 및 대체를 통해 어떻게 진화 되어가는지를 살펴보았다. 대표적인 통신사업자인 KT는 막강한 자금력을 바탕으로 시장 확대 및 경쟁사와의 차별화를 위해 VDSL 서비스 조기도입을 서두르고 있고, 하나로는 자금의 열세로 인한 ADSL 투자비를 회수 할때까지 VDSL 서비스를 연기하고 있는 실정이다. ADSL과 VDSL 두 기술의 관계는 Lotka-Volterra Competition (LVC) 모델을 이용한 시뮬레이션 결과를 통해 빠른 속도와 비슷한 가격대의 VDSL이 침략자(predator)로 기존 시장 지배자인 ADSL을 사냥감(prey)으로 빠른 속도로 대체해 나가는 것을 알 수 있었다.

• Fire Science and Engineering
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• v.34 no.1
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• pp.55-65
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• 2020

In this study, the ISO 5660 and ISO 5659 combustion tests were conducted with synthetic resin conduits (CD, VE) and metal conduit (ST) used for wiring work in electrical facilities, which can be installed in ceiling concealed places. Then, fire spreading and evacuation risks were analyzed based on the measured data. In the ISO 5660 test, CD of 120.5 MJ/㎡, VE of 81.9 MJ/㎡, and ST of 4.9 MJ/㎡ were measured. In the ISO 5659 test, the CD 1320, VE 731, and ST 102 were measured, and then the maximum smoke densities were measured for CD 605 s, VE 740 s, and ST 1,200 s. In terms of fire spreading and evacuation risk, the CD conduit, VE conduit, and ST conduit were in order. In the fire spreading risk analysis, total heat emission was calculated as 4,820 MJ/㎡, 4,267 MJ/㎡, and 196 MJ/㎡ for CD, VE, and ST, respectively. Evacuation risk analysis shows at transmittance of 89%, CD is 127 s, VE is 35 s, and ST is 969 s. At transmittance of 79%, representing almost invisible concentration, CD is 157 s and VE is 50 s. The CD and VE conduits had a high fire spreading and evacuation risks, while the ST conduit had little effect on fire spreading and evacuation risk.

• Fire Science and Engineering
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• v.27 no.4
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• pp.21-26
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• 2013

This study was performed to test the combustive properties of Pinus rigida plates treated with bis-(dimethylaminomethyl) phosphinic acid (DMDAP), bis-(diethylaminomethyl) phosphinic acid (DEDAP), and bis-(dibuthylaminomethyl) phosphinic acid (DBDAP). Pinus rigida specimens were painted in three times with 15 wt% bis-(dialkylaminoalkyl) phosphinic acid solutions at the room temperature. After drying specimen treated with chemicals, combustive properties were examined by the cone calorimeter (ISO 5660-1). It is supposed that the combustion-retardation properties were improved by the partial due to the treated bis-(dialkylaminoalkyl) phosphinic acids in the virgin Pinus rigida. Especially, the specimens treated with chemicals showed both the lower total smoke release rate (TSRR) ($16.94{\sim}18.92m^2/m^2$) and lower $CO_{2mean}$ production (1.98~2.09 kg/kg) than those of virgin plate. However the specimens treated with chemicals showed both the higher peak mass loss rate (PMLR) (0.1250~0.1297 g/s) and higher 1st-smoke production rate (SPR) (0.0153~0.0167 g/s) than those of virgin plate. Compared with virgin Pinus rigida plate, the specimens treated with the bis-dialkylamimoalkyl phosphinic acids showed partially low combustive properties.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.5
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• pp.75-82
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• 2010

To study the combustion characteristics of forest fuel by fire intensity, the experiment of combustion characteristics on Pinus Densiflora living leaves, which is the weakest species to the forest fire, was delivered, using variables of heat flux(25 kW/$m^2$, 50 kW/$m^2$, 75 kW/$m^2$). With the equipment of Cone calorimeter, the characteristics of ignition, heat, smoke release, CO and $CO_2$ release, and mass loss were analyzed. Pinus Densiflora living leaves containing moisture of 60.66% were not ignited at the heat flux of variables 25 kW/$m^2$, 50 kW/$m^2$, 75 kW/$m^2$. In proportion to the heat flux value, heat release amount and heat release rate reached maximum value rapidly: higher variables came to the maximum by the half rapidity and the maximum value were twice higher than the former lower variables respectively. As for the smoke release, the less heat flux the variable had, the more smoke release it had, due to incomplete combustion. The release amount of CO and $CO_2$ had more maximum value as the heat flux increased and more radiant heat meaned more carbon oxide. When the forest fire breaks out, therefore, a great amount of CO and $CO_2$ will be released by Pinus Densiflora.

• Journal of Distribution Research
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• v.16 no.4
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• pp.29-64
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• 2011

Overview of Research: Product availability is one of important competences of store to fulfill consumer needs. If stock-outs which means a product what consumer wants to buy is not available occurs, consumer will face decision-making uncertainty that leads to consumer's negative responses such as consumer dissatisfaction on store. Stockouts was much studied in the field of academia as well as practice in other countries. However, stock-outs has not been researched at all in Marketing and/or Distribution area in Korea. The main objectives of this study are to find out determinants of consumer responses such as Substitute, Delay, and Leave(SDL) when consumer encounters out-of-stock situation and then to examine the effects of these factors on consumer responses. Specifically, this study focuses on situational characteristics(e.g., purchase urgency and surprise), store characteristics (e.g., product assortment and store convenience), and consumer characteristics (e.g., brand loyalty and store loyalty). Then, this study empirically investigates relationships these factors with consumers behaviors such as product substitution, purchase delay, and store switching.