• Fire Science and Engineering
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• v.33 no.2
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• pp.30-38
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• 2019

Tracking, which is one of the main causes of electrical fires, is perceived as a physical phenomenon of electrical discharge. Hence tracking should be explained based on electric field analysis, conduction path by electron generation, and gas discharge physics. However, few papers have considered these details. This paper proposes a tracking mechanism including their effects on tracking progress. In order to prove this mechanism, a tracking experiment, an electric field analysis for the carbonization evolution model, and an explanation of the tracking process by gas discharge physics were conducted. From the tracking experiment, the current waveforms were measured at each stage of the tracking progress from corona discharge to tracking breakdown. The electric field analysis was carried out in order to determine the electric field on the surface of a dry-band and the high electric field region for electron generation during the generation and progress of carbonization. In this paper, the proposed tracking mechanism consisted of six stages including electron avalanche by corona discharge, accumulation of positive ions, expansion of electron avalanche, secondary electron emission avalanche, streamer, and tracking by conductive path. The pulse current waveforms measured in the tracking experiment can be explained by the proposed tracking mechanism. The results of this study will be used as the technical data to detect tracking phenomenon, which is the cause of electric fire, and to improve the proof tracking index.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.727-730
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• 2023

The operation of electric automatic windows is used in harsh environments, and the energy density decreases as charging and discharging are repeated, and as soundness deteriorates due to damage to the internal separator, the vehicle's mileage decreases and the charging speed slows down, so about 5 to 10 Batteries that have been used for about a year are classified as waste batteries, and for this reason, as the risk of battery fire and explosion increases, it is essential to diagnose batteries and estimate SOH. Estimation of current battery SOH is a very important content, and it evaluates the state of the battery by measuring the time, temperature, and voltage required while repeatedly charging and discharging the battery. There are disadvantages. In this paper, measurement of discharge capacity (C-rate) using a waste battery of a Tesla car in order to predict SOH estimation of a lithium-ion battery. A Support Vector Machine (SVM), one of the machine models, was applied using the data measured from the waste battery.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.07a
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• pp.241-242
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• 2019

4차 산업 혁명에 맞춰 빠르게 발전하고 1990년대부터 등장하기 시작했던 '인텔리전트 빌딩'이 다시 주목을 받고 있다. 센서와 컴퓨터가 내장된 사물들이 인터넷으로 연결되어 각종 서비스를 제공하여 환경을 변화시키고 삶이 편해지고 있다. 그럼에도 불구하고 편리함을 추구하는 기존 기술 들은 대기업들이 주를 이루어 관리를 하게 되고 있고 유지 보수비용이 많이 들어 스마트 기기에 능숙하지 않은 부분도 있어 본 논문은 보다 기존의 IOT 기술보다 유지 보수비용의 절감과 손쉬운 접근방식을 제공한다. 본 논문인 '구글 어시스턴트를 이용한 스마트 홈 제어'는 집 전체를 제어하여 조명, 냉난방, 환기 등을 조절하고 무단 침입자를 감지하며 경고음을 알려주는 것이다. 예를 들어 집 주인이 외출을 하였는데 가스렌지의 불을 안 끄고 나왔거나 조명을 안 끄고 나왔는데 집을 다시 들어가기 어려운 상황일 때 핸드폰으로 버튼 하나만 누르면 제어가 된다. 본 논문의 목적은 집안의 화재나 전기 요금절감을 위하고 편리한 삶을 추구하고자 개발 되었다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.01a
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• pp.155-156
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• 2020

세상은 4차 산업 혁명 시대에 들어섰고 사회의 많은 부분들이 스마트화되었다. 이러한 기술들의 발전으로 집 안의 가전기기들을 태블릿 pc, 스마트폰 등을 통하여 장소와 시간에 구애받지 않고 관리할 수 있게 되었다. 하지만 모든 전자 제품들이 전력 사용량을 알 수 있는 것은 아니다. 그렇기에 대부분의 가정이 전력이 과소비되고 있는 것은 아닌지 외출 시 전열 기구의 전원이 제대로 꺼졌는지 등 이를 확인이 쉽지 않다. 본 과제물은 위의 문제를 해결하기 위해 아두이노로 라즈베리파이와 앱을 무선통신하여 '전력사용 확인이 가능한 전원제어 시스템'을 고안했다. 전력측정이 가능한 플러그를 사용하여 가전제품의 전력 사용량을 측정할 수 있으며 전원을 원격으로 제어할 수 있다. 또한, 터치스크린으로도 이것을 실시간으로 확인할 수 있으며, 애플리케이션과 같은 역할 수행이 가능하다. 이 기능으로 전력의 과소비 및 누전으로 인한 화재를 막고 전기세를 최대한으로 줄이면서 동시에 편리함을 증대 시킬 수 있다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.6
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• pp.99-106
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• 2010

This paper proposes a novel design of enhanced auto light control system using PLC(Power Line Communication) and SMS(Short Message Service) to copy with emergent cases effectively. In the proposed system, the indoor sensing system is designed to send emergent messages to the users or system manager in case of fire or invasion, which may prevent secondary accident. In addition, data transmission using PLC may drastically decreases the number of lines. The experimental results show the effectiveness of the proposed system.

• Fire Science and Engineering
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• v.31 no.5
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• pp.53-62
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• 2017

Electric power which is the energy source of economy and industries requires long distance transportation due to regional difference between its production and consumption, and it is supplied through the multi-loop transmission and distribution system. Prior to its actual use, electric power flows through several transformations by voltage transformers in substations depending on the characteristics of each usage, and a transformer has the structure consisting of the main body, winding wire, insulating oil and bushings. A transformer fire that breaks out in substations entails the primary damage that interrupts the power supply to houses and commercial facilities and causes various safety accidents as well as the secondary economic losses. It is considered that causes of such fire include the leak of insulating oil resulting from the destruction of bottom part of bushings, and the chain reaction of fire due to insulating oil that reaches its ignition point within 1 second. The smoke detector and automatic fire extinguishing system are established in order to minimize fire damage, but a difficulty in securing golden time for extinguishing fire due to delay in the operation of detector and release of gas from the extinguishing system has become a problem. Accordingly, this study was carried out according to needs of active mechanism to prevent the spread of fire and block the leak of insulating oil, in accordance with the importance of securing golden time in extinguishing a fire in its early stage. A bushings fireproof structure was developed by applying the high temperature shape retention materials, which are expanded by flame, and mechanical flame cutoff devices. The bushings fireproof structure was installed on the transformer model produced by applying the actual standards of bushings and flange, and the full scale fire test was carried out. It was confirmed that the bushings fireproof structure operated at accurate position and height within 3 seconds from the flame initiation. It is considered that it could block the spread of flame effectively in the event of actual transformer fire.

• Journal of the Korean Institute of Gas
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• v.28 no.1
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• pp.85-99
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• 2024

As the proliferation of hydrogen electric vehicles accelerates, there is observed diversification in hydrogen refueling station models. This diversification raises safety concerns for different types of stations. This study conducted a quantitative risk assessment of a multi-vehicle hydrogen station, capable of simultaneously refueling cars, buses, and trucks. Utilizing Gexcon's Effects&Riskcurves Software, scenarios of fire and explosion due to hydrogen leaks were assessed. The study calculated the impact distances from radiative heat and explosion overpressure, and measured risks to nearby buildings and populations. The largest impact distance was from fires and explosions at dispensers and high-pressure storage units. High-pressure storage contributes most significantly to personal and societal risk. The study suggests that conservative safety distances and proper protective measures for these facilities can minimize human and material damage in the event of a hydrogen leak.

• Journal of Internet Computing and Services
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• v.24 no.6
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• pp.171-180
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• 2023

Hydrogen energy technology is gaining importance in the era of the Fourth Industrial Revolution, offering military advantages when applied to military vehicles due to its characteristics such as reduced greenhouse gas emissions, noise, and low vibration. Korea's military has initiated the Army Tiger 4.0 plan, focusing on hydrogen application, downsizing, and AI-based smart features. The Ministry of National Defense plans to collaborate with the Ministry of Environment to expand hydrogen charging stations nationwide, anticipating increased deployment of military hydrogen vehicles. However, considering the Jet Fire and VCE(Vapor Cloud Explosion) nature of hydrogen, ensuring safety during installation is crucial. Current military guidelines specify a minimum safety distance of 2m from adjacent buildings for charging stations. Scientific methods have been employed to quantitatively assess the accident damage range of hydrogen, proposing a minimum safety distance beyond the affected area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.588-594
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• 2020

This study proposes non-destructive rebound-hardness and ultrasonic testing methods to more accurately evaluate the residual structural performance of reinforced concrete structures in a fire. Techniques are also proposed to assess the stiffness used in the deflection calculation with natural frequencies obtained by vibration tests. In the compressive strength evaluation using rebound hardness, the residual compressive strength of thick specimens and a larger water/cement (W/C) ratio were shown to be large. The homogeneity of concrete at high temperature compared to ambient temperature conditions was assessed by the velocity of ultrasonic waves that penetrate the concrete, and it followed W/C or thickness of slab makes little different results. To assess the stiffness of fire-damaged slabs and increase in deflection, the natural frequency was measured by vibration tests and incorporated into the equation of the stiffness. The application of this technique to the slab experiment showed that it can be a very reasonable evaluation technique. In addition, to evaluate the residual strength of a member after fire, a test of the strength of a component was carried out during and after heating.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.1
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• pp.63-70
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• 2024

Lithium-ion batteries (LIB) are widely used in various sectors, such as transportation (e.g., electric vehicles (EV)) and energy (e.g., energy storage facilities) due to their high energy density, broad operating temperature (-20 ℃ ~ 60 ℃), and high capacities. LIBs are powerful but fragile on external factors, including pressure, physical damage, overheating, and overcharging, that cause thermal runaway causing fires and explosions. During a LIB fire, a large amount of oxygen is generated from the decomposition of ionogenic materials. A water fire extinguisher that helps with cooling and suffocating must be essentially required at the same time. In fact, however, it is difficult to suppress LIB fires in the case of EVs because a LIB is installed with a battery pack housing that interrupts direct extinguishing by water. Thus, this study aims to investigate effective fire extinguishing measurements for LIB fires by using an EV. Relevant documents, including research articles and reports, were reviewed to identify effective ways of LIBs fire extinguishing. A real-scale fire experiment generating thermal runaway was carried out to figure out the combustion characteristics of EVs. This study revealed that the most effective fire extinguishing measurements for LIB fires are applying fire blankets and water tanks. However, there is still a lack of adequate regulation and guidelines for LIB fire extinguishment. Taking this into account, developing functional fire extinguishment measurements and available regulatory instruments is an urgent issue to secure the safety of firefighters and citizens.