• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.1
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• pp.37-44
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• 2007

This paper describes characteristics for copper oxide growth of polyvinyl chloride(PVC) insulated wires by series arc. In this experiment, 600V IV wires were used, and characteristics of oxide growth and ignition process were analyzed in case load was 300W, 460W and 600W, respectively. In the result of experiment, covering materials were molten, carbonized and ignited, whereas, oxidized materials were grown in conducting material. During copper oxide was growing, contact voltages and power dissipations increased. When there is copper oxide growth, the waveform of current showed sinusoidal waveform, and the waveform of voltage showed modified waveform. Oxidized materials were heated at about $905^{\circ}C$, surface structure showed irregular shapes, and cross-section showed multiple cracks. And, the results of this experiment were applied to the fire cause analysis of fire evidence collected at the fire scene.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.51-51
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• 2018

기후변화에 따른 기온이 상승 및 강수 패턴의 변화로 인하여 자연재해로 인한 피해가 증가하고 있다. 다른 자연재해들과는 달리 가뭄은 공간적 및 가뭄에 영향을 받는 사회적, 경제적, 환경적 및 심리적인 피해 등에 있어 대단히 광범위하다. 특히, 오랜 기간 동안의 무강우로 인해 자연생태계의 균형을 변화시켜 많은 물고기와 야생 생물 종에 해를 끼칠 수 있으며, 식물 성장 저하, 화재 및 곤충 발생의 증가, 물 순환 및 지방 종의 멸종 증가와 같은 환경학적 문제를 야기할 수 있다. 우리나라의 또한 폭염과 마른 날씨로 인하여 멸종위기종의 어류 서식지를 잃는 등의 문제가 발생하기도 하였다. 이러한 환경-생태학적 가뭄의 발생빈도가 증가하고 있으나, 이에 대한 많은 연구가 이루어지지 못한 질정이다. 따라서 본 연구에서는 가뭄에 따른 환경-생태학적 영향 등을 파악하고, 이에 따른 하천 수질과 식생의 변화 등을 분석하여 가뭄 상태에 따른 환경-수생태의 영향을 살펴보고자한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.1020-1023
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• 2011

최근 스마트 모바일이 성장하면서 다양한 서비스들이 이루어지고 있다. 그 중에 모바일 오피스를 사용할 때 내부 망을 방문해야 한다. 그에 대한 보안 문제는 매우 중요하다. 본 논문은 모바일 기기가 내부 망에 방문할 때 사용자를 인증하기 위하여 통신의 보안 터널과 VPN(Virtual Private Network)기술을 사용하고, 모바일 기기가 내부 망에 방문할 때 OTP(One-Time Password)와 같은 동적인 패스워드 인증을 통해서 안전한 터널과 인증 서비스를 제공한다.

• Fire Science and Engineering
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• v.26 no.5
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• pp.35-40
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• 2012

Numerical investigation was performed to study on the soot formation characteristics in the WSR according to the CO addition. Ethylene and pure air were used as a fuel and an oxidizer, respectively, and three different equivalence ratios (2.0, 2.5, 3.0) were used in the calculation. The resulted CO mole fraction of 10 % CO addition showed the maximum value in spite of the least CO supply. This means that the conversion of CO to soot and other carbon compounds is weakened under incipient soot formation. The soot volume fraction was decreased with increasing the CO addition because the important species for soot formation such as pyrene and acetylene, were decreased with the addition of CO. When the equivalence ratio was 2.5, the soot volume fraction shows the highest value, which results from the contribution of fuel rich condition and reacting temperature. Furthermore, surface growth rate and species concentrations justified the HACA mechanism for soot formation.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.3
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• pp.242-248
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• 2017

Recently, Population has been concentrated in cities due to rapid economic growth. As a result, urban buildings are becoming more dense, high-rise, and diversified. The shape of these urban buildings increases the risk of fire, accidents and crime. The narrow living space has the characteristic of the unchanged floor. In case of a fire, the living space of the narrow residence is large in the damage because the smoke diffusion rate is fast. The radio wave transmittance and transmission distance of wireless communication used in fire fighting operations vary depending on the type of building materials and buildings. Therefore, this paper analyzes the building materials and structural characteristics of the narrow residential space for efficient fire fighting operations. We have developed a communication environment solution for a narrow residential space for the optimal fire fighting operation through the measurement of the radio wave transmittance and the transmission distance of the wireless communication.

• Fire Science and Engineering
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• v.31 no.6
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• pp.83-90
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• 2017

If an overcurrent exceeding the rated value is applied to an electric wire, the temperature of the electric wire increases, and the electric wire covering deteriorates to cause a short circuit. The upper limit temperature of the wire varies according to the magnitude of the overcurrent. When a short circuit occurs at each upper temperature limit, a cooling speed difference occurs during the solidification process due to the temperature difference between the short circuit temperature and the wire surface temperature. At this time, the pattern characteristics of the dendritic structure formed on the molten cross section are different. In this study, the upper temperature limit, which varied according to the overcurrent magnitude, was measured. At the time a short circuit occurred, the second branch spacing (dendrite Arm Spacing : DAS) of the dendrite was analyzed and the numerical value was quantified. The experimental results showed that the upper temperature limit increases with the magnitude of the overcurrent, and that the second branch spacing increases with increasing wire temperature.

• Fire Science and Engineering
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• v.33 no.4
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• pp.97-104
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• 2019

Behind the growth of the chemical industry which is a cornerstone of the Korean economy, dozens of hazardous and noxious chemical accidents occur every year, resulting in enormous casualties and environmental damages. Many cases among chemical accidents are caused by the carelessness of workers in handling facilities such as hydrochloric acid and hydrofluoric acid, and the aging of handling facilities. In order to mitigate the damage by such chemical accidents, a safety system for preventing atmospheric diffusion of hazardous and xoxious chemicals in dike was proposed. The atmospheric diffusion prevention safety system consists of leak detection phase, alarm and measurement phase, suppression and blocking phase. Through the proposed the atmospheric diffusion prevention safety system, the need for 2nd chemical accident prevention such as atmospheric diffusion in dike can be posed.

• Fire Science and Engineering
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• v.33 no.1
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• pp.171-178
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• 2019

The disaster and safety R&D budget has continued to increase since 2008, but the fire safety R&D budget is a small part. Therefore, successful outcomes that could lead to the economic growth of the fire safety industry have not been achieved. This paper suggests a fire safety R&D budget expansion, reinforcement of R&D capacity, and performance growing plan by analyzing the factors that affect the performance of a fire safety R&D project. Empirical analysis was performed through one-way ANOVA and regression analysis using the statistical program, SPSS statistics 21.0. As a result, this study suggests that the continuous expansion of R&D funds and the securing of excellent trained research manpower will be necessary to obtain qualitatively superior patents and papers.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.8
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• pp.1058-1063
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• 2020

This paper presents a new insulation resistance calculation technique to prevent electric shock and fire accidents due to the dielectric breakdown in the primary insulation section of the IT ground system. The solar power generation market is growing rapidly due to the recent expansion of renewable energy and energy storage systems, but as the insulation is destroyed and fire accidents frequently occur, a device for monitoring the insulation resistance state is indispensable to the IT grounding method. Compared to the conventional algorithm that use a method of multiplying a time constant to a fixed coefficient, the proposed insulation resistance calculation method has a fast response time and high accuracy over a wide insulation resistance range by applying a different coefficient according to the values of the insulation impedance. The proposed dynamic time constant based insulation resistance calculation technique reduces the response time by up to 39.29 seconds and improves the error rate by 20.11%, compared to the conventional method.

• The Korean Journal of Applied Statistics
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• v.30 no.3
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• pp.363-376
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• 2017

The insurance market is saturated and its growth engine is exhausted; consequently, the insurance industry is now in a low growth period with insurance companies that face a fierce competitive environment. In such a situation, it will be an important issue to find the probability distributions that can explain the flow of insurance claims, which are the basis of the actuarial calculation of the insurance product. Insurance claims are generally known to be well fitted by lognormal distributions or Pareto distributions biased to the left with a thick tail. In recent years, skew normal distributions or skew t distributions have been considered reasonable distributions for describing insurance claims. Cooray and Ananda (2005) proposed a composite lognormal-Pareto distribution that has the advantages of both lognormal and Pareto distributions and they also showed the composite distribution has a higher fitness than single distributions. In this paper, we introduce new composite distributions based on skew normal distributions or skew t distributions and apply them to Danish fire insurance claim data and US indemnity loss data to compare their performance with the other composite distributions and single distributions.