• Journal of the Korea Society of Computer and Information
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• v.28 no.1
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• pp.65-70
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• 2023

In this paper, we propose a CCTV storage space securing model using YOLO v3. CCTV is installed and operated in various parts of society for disasters, disasters and safety such as crime prevention, fire prevention, and monitoring, and the number of CCTV is increasing and the quality of the video quality is improving. Due to this, as the number and size of image files increase, it is difficult to cope with the existing storage space. In order to solve this problem, we propose a model that detects specific objects in CCTV images using YOLO v3 library and deletes unnecessary frames by saving only the corresponding frames, thereby securing storage space by reducing the size of the image file, and thereby Periodic images can be stored and managed. After applying the proposed model, it was confirmed that the average image file size was reduced by 94.9%, and it was confirmed that the storage period was increased by about 20 times compared to before the application of the proposed model.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2255_2256
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• 2009

주택용 분전반내의 과부하 차단기(MCCB)나 누전차단기(ELCB)들은 전류 RMS 크기만을 가지고 고장전류를 인식하기 때문에 아크고장전류를 차단하지 못해, 수용가들은 전기화재로 인한 심각한 인명피해나 재산상의 손실을 자주 경험할 수 있다. 따라서 본 연구에서는 이러한 문제를 해소하기 위해 아크진단 기능을 가지는 지능형 분전반을 제안하고자 한다. 특히 여기에서는 아크고장 진단 기능을 고려한 지능형 분전반의 단상 전력관리 모듈 설계연구를 주 목적으로 한다.

• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.110-112
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• 2007

누전으로 인한 전기화재나 감전사고와 같은 전기재해는 저항성 누전전류에 의해 발생하므로 전선로에서 저항성 누전전류의 측정은 매우 중요하다. 따라서 본 논문에서는 합성 누전전류로부터 저항성 누전전류를 산출할 수 있는 이론을 제시하였고 이것을 실제 회로로 구현하였다. Multiplier와 저역통과필터를 통과한 합성 누전전류신호는 저항성 누전전류의 크기에 해당하는 직류 전압신호로 출력된다 따라서 Multiplier와 R-C 필터를 이용하여 간편하게 저항성 누전전류를 구할 수 있었다. 그리고 누전실험을 통하여 저항성 누전전류와 용량성 누전 전류가 합쳐진 합성 누전전류에서 저항성 누전전류를 정확하게 산출하는 것을 확인하였다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.7
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• pp.269-274
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• 2016

This paper aims to suggest the water curtain installation guideline for prevention of fire spread. The water curtain systems play a role in preventing fire spread which is caused by fire flames and radiation heat release from a fire source. The radiation attenuation ratio is affected by the water droplet size, vertical distance from the nozzle and flow rate. This study suggests the water curtain installation guideline as follows : (1) Investigation of a reference store array (2) Calculation of the number of drencher heads (3) Review of the relationship between droplet size and attenuation factor depending on the height of the drencher head (4) Review of a drencher head array and spray overlapping. The reference traditional market in which a fire compartment is installed using a water curtain can be predicted to have a radiation attenuation ratio of 50%.

• The Safety technology
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• no.98
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• pp.92-107
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• 2006

전기는 가정, 직장, 공장, 빌딩, 아파트 등 국가 기간산업의 동력원으로서 상시 접하고 사용하기 때문에 무의식 속에서 취급하고 있지는 않는가 생각하여 보자. 전기는 냄새도, 색도, 소리도, 크기도, 보이지도 아니하기 때문에 위험한지, 안전한지 상관하지 않고 있지는 않는가? 편리하다고 주의를 하지 아니하고 사용하면 큰 피해를 일으켜 생명과 재산에 큰 손실을 가져올 수 있다. 전기의 바른 사용법과 취급요령을 습관화하여 위험을 방지하여야하며 바로 알고 안전하게 사용해야 한다. 전기재해는 주로 감전과 화재로 구별할 수 있으며, 그 중에서도 감전으로 인한 인사사고 방지가 첫째 요건으로 전기설비 기술기준에서는 모든 전기설비에 사용기준을 의무 사항으로 규정되어 있다. 산업체에서는 대부분이 저압 전기설비이고, 또 작업자가 온종일 접하게 되는 것이 저압 전기설비이다. 또한 감전재해의 대부분이 저압 전기설비에서 발생하게 됨으로 이들 설비의 안전관리를 철저히 하여 재해를 예방하여야 한다.

• Journal of the Korea Concrete Institute
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• v.14 no.4
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• pp.449-456
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• 2002

Recently, the application of high strength and high performance concrete has been gradually increased as an important construction material for high rise and huge scaled construction. However, high performance concrete has undesirable characteristics of spalling subjected to high temperature due to its dense microstructure content. A spalling by fire brings surface failure and falling off concrete member. It is considered that spalling by fire should be taken into account for the safety of the concrete structure under fire. Therefore, in this paper, tests are carried out using high performance concrete containing polypropylene(PP) fiber in order to improve the fire resistance performance. PP fiber contents and member sizes are varied. According to experimental results, as for the influence of PP fiber contents, all the test specimens without PP fiber show entire failure in W/C of 35％, while they show nearly sound shape except some kinds of surface fracture in W/C of 55％. When PP fiber is contained more than 0.07％, favorable prevention effects of spatting by fire are obtained. As for the effects of test specimens size, it tends to increase the possibilities of spatting by fire as test specimens become larger. And spatting by fire at the edge of test specimens occurs more frequently than at the surface of test specimens. Residual compressive and tensile strength shows 45∼65 ％ of its original strength at W/C of 35％, and 30∼40％ at W/C of 55 ％.

• Fire Science and Engineering
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• v.22 no.3
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• pp.258-264
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• 2008

This study proposes the experimental methods which shows various guidelines for systematic study of surface forest fuels. The thermal characteristics of surface fire fuels such as Quercus Variabilis and Pinus Densiflora fallen leaves are measured using TGA and Oxygen Bomb Calorimeter. Both of them are common species of Korean forest. Also the combustion characteristics of surface fire fuels are analysed according to the methods which are commonly used in Pool Fire analysis. The measured parameters are gas velocity, temperature, flame height, heat release rate and mass loss rate. A system is designed to simulate the surface fire. Methods and results are shown for the application of forest fire study.

• Journal of the Korea Concrete Institute
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• v.23 no.4
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• pp.431-440
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• 2011

Concrete structures exposed to fire produce changes in their internal structure, resulting in their service life reduction due to the deterioration of its strength and performance capacity. The deterioration level are dependent on the temperature, exposure time, concrete mix proportions, aggregate property, and material properties. This study was performed to evaluate the thermal behavior of ultra-high strength concrete for the parameters of water to cement ratio (compressive strength), fine to total aggregate ratio, and maximum coarse aggregate size. At room temperature and $500^{\circ}C$, tests of ultrasonic pulse velocity, resonance frequency, static modulus of elasticity, and compressive strength are performed using ${\varnothing}100{\times}200\;mm$ cylindrical concrete specimens. The results showed that the residual mechanical properties of ultra-high strength concrete heated to $500^{\circ}C$ is influenced by variation of a water to binder ratio, fine to total aggregate ratio, and maximum coarse aggregate size.

• Fire Science and Engineering
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• v.17 no.2
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• pp.56-61
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• 2003

The smoke removal rate from a room with an opening was investigated for different smoke control systems by using the large eddy simulation turbulence model of the Fire Dynamics Simulator. The decreasing rate of the particles randomly distributed in the 2m X 2m X 2.4m room was com-pared for the ventilation system, pressurization system and extraction system, and for the air flowrate of the ventilation system. Difference in the smoke removal rate among the three smoke control systems was small when the opening was closed. The pressurization system showed less smoke removal rate than the other two systems when the opening existed, and hence is not recommended for subway stations with large openings. It was also shown that a less flowrate in the ventilation system leads to a much longer smoke removal time.

• Fire Science and Engineering
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• v.27 no.1
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• pp.20-25
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• 2013

This study is experimentally analyzed to extract the major parameters affecting the performance of the smoke-control system and the relations of pressure difference between vestibule and supply air pressure zone effect of supply mass flow rate and leakage area in the smoke-control zone. To obtain this, the mock-up building of three-story scale with a total of 10 compartments was constructed, and several apparatus were also installed for in-situ measurement of the ventilation flow rate, pressure difference between compartments, smoke defensive air velocity, the opening-closing force of door, etc. This article show that pressure difference in the smoke-control zone is significantly related with leakage area of vestibule in low pressure region, leakage area of supply air pressure in over pressure region and both of them in pressure control region when the pressure control range of damper is 45 Pa~55 Pa.