• Journal of the Korean Society of Safety
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• v.37 no.5
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• pp.14-21
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• 2022

The purpose of this study was to apply the signal pattern recognition technique to the digital wireless fire-alarm system and to reduce unwanted fire alarms. In this study, the fire alarms of the K Institute, which operates the largest digital wireless fire-alarm system in Korea, were classified into normal operations and unwanted fire alarms, and these were analyzed and compared with actual fire signals. In addition, by designing a non-fire signal filter and applying it to the K Institute, we confirmed that the monthly unwanted fire alarm rate of all 5,713 detectors decreased sharply. In particular, the unwanted fire alarm rate for flame decreased from 1.09% to 0.11% and the unwanted fire alarm rate for smoke decreased from 0.65% to 0.035%.

• 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.

• ETRI Journal
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• v.42 no.4
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• pp.480-490
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• 2020

More than 42 000 fires occur nationwide and cause over 2500 casualties every year. There is a lack of specialized equipment, and rescue operations are conducted with a minimal number of apparatuses. Through-the-wall radars (TTWRs) can improve the rescue efficiency, particularly under limited visibility due to smoke, walls, and collapsed debris. To overcome detection challenges and maintain a small-form factor, a TTWR system-on-chip (SoC) and its architecture have been proposed. Additive reception based on coherent clocks and reconfigurability can fulfill the TTWR demands. A clock-based single-chip infrared radar transceiver with embedded control logic is implemented using a 130-nm complementary metal oxide semiconductor. Clock signals drive the radar operation. Signal-to-noise ratio enhancements are achieved using the repetitive coherent clock schemes. The hand-held prototype radar that uses the TTWR SoC operates in real time, allowing seamless data capture, processing, and display of the target information. The prototype is tested under various pseudo-disaster conditions. The test standards and methods, developed along with the system, are also presented.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.3 s.96
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• pp.313-319
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• 2005

Instruction and prevention of the safety for a fire have been performed continuously by nation. However, the accident due to a fire is not decreasing and causes a serious calamity to people. It is at the initial stage of fire burning that the most effective way to reduce damage is to evacuate and fight a fire. When a fire burns, the equipments reporting to other person or organization concerned are called 'acoustic reporting equipment'. Among those equipments reporting to person, 'a fire bell' is the easiest equipment to approach. Observing the behaviors of people when a fire burning, some are in a quiet indoor, some in a room with other people, some in a square with many people and some in indoor filled with smoke etc. This study aims to find out an acoustic reporting signal appropriate for visual information. For the experiments, visual-auditory experiments were performed through reporting signals and visual informations with several situations that is able to be faced at when a fire burns.

• IE interfaces
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• v.19 no.1
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• pp.43-52
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• 2006

In order to make best use of NC machine tools with minimal labor costs, they need to be in operation 24 hours a day without being attended by human operators except for setup and tool changes. Thus, unattended machining is becoming a dream of every modern machine shop. However, without a proper mechanism for real-time monitoring of the machining processes, unattended machine could lead to a disaster. Investigated in this paper are ways to using PC camera as a real-time monitoring system for unattended NC milling operations. This study defined five machining states READY, NORMAL MACHINING, ABNORMAL MACHINING, COLLISION and END-OF-MACHINING and modeled them with DEVS (discrete event system) formalism. An image change detection algorithm has been developed to detect the table movements and a flame and smoke detection algorithm to detect unstable cutting process. Spindle on/off and cutting status could be successfully detected from the sound signals. Initial experimentation shows that the PC camera could be used as a reliable monitoring system for unattended NC machining.

• Journal of architectural history
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• v.32 no.1
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• pp.35-45
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• 2023

Bongsu(Beacon Fire Station) is a facility that sends signals with fire and smoke and has been used in Korea since the Three Kingdoms period. This facility was installed to know the north and south crises. This trend continues until the Joseon Dynasty, and it has been somewhat completed in the 17th century. In previous studies, beacon fire was identified mainly from the border area to Hanyang. Based on this, it was classified into Gyeongbongsu, Yeonbyeonbongsu, and Naejibongsu. However, it is difficult to define the characteristics of beacon fire in coastal areas only with this classification. In the case of beacon fire in island areas, there was a tendency to value communication connection within the region rather than connection with the capital. As a case analysis for this, an academic review was conducted with the cases of Ganghwa Island and Jeju Island. As a result, it was confirmed that the role and character of the beacon vary depending on the defense system and the physical distance from the land, even if it has the topographical commonality of the same island.

• Journal of the Korean Institute of Gas
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• v.16 no.6
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• pp.128-135
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• 2012

In this paper, we proposed a system and a scenario to raise efficiency of gas safety management by developing wireless ZigBee communication modules, smart-home gas safety appliances and the system suitable for gas safety. Our designed system consists of a micom gas meter, an automatic extinguisher, sensors, and a wall-pad. A micom-gas-meter monitors gas flow, gas pressure, and earthquake. An automatic fire extinguisher checks combustible gas leaks and temperature of $100^{\circ}C$(cut off) and $130^{\circ}C$(fire). Sensors measure smoke and CO gas. In our novel system, a micom-gas meter cut off inner valve with warnings, an automatic fire extinguisher cut off middle valve and spray extinguishing materials, and sensors generate signals when detecting smoke and CO and then take a next action. Gas safety appliances and sensors automatically takes measures, and transmit those information to a wall-pad. The wall-pad again transmits real time information to server. Users can check and manage gas safety situations by connecting BcN server through web or mobile application. We hereby devised scenarios for gas safety and risk management based on the smart, and demonstrated their efficiency through test applied to filed.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.3
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• pp.13-20
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• 2011

In this paper, we proposed a system to raise gas safety management by using the wireless communication module and intelligent gas safety appliances. Our designed systems configure a micom-gas meter, an automatic extinguisher, sensors, and a wallpad. A micom-gas-meter monitors gas flow, gas pressure, and earthquake. An automatic fire extinguisher checks gas(combustible) leaks and temperature of $100^{\circ}C$ and $130^{\circ}C$. Sensors measure smoke and CO gas. In our novel system, a micom-gas meter cut off inner valve with warnings, an automatic fire extinguisher cut off middle valve and spray extinguishing materials, and sensors generate signals for smoke and CO when occurring gas risk. Gas safety appliances and sensors takes safety measures, and transmit those signal to a wallpad. The wallpad again transmit signal like events to a control server. Users can connect web pages for gas safety through B-ISDN and control and manage them. We hereby devised scenarios for gas safety and risk management, and demonstrated their effectiveness through experiments.

• Journal of the Society of Disaster Information
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• v.13 no.1
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• pp.51-58
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• 2017

This paper proposes a direction estimation scheme with directional speaker and smart device for evacuation guidance. When there is worst disaster environment filled with smoke and noisy sound, evacuee can not get any information about evacuation routes. The proposed scheme can be used for detecting evacuation routes with audible and inaudible signal from directional speaker. At this point, evacuee can get evacuee guidance by using smartphone application that the proposed scheme is applied. The performance of the proposed scheme is evaluated by experiment with three different types of smart devices in large indoor environment. The purpose of experiment is to detect the direction of transmitted signal from directional speaker. Therefore, The experiment is conducted by analyzing the strength of transmitted signal by distance. The experimental results show that even if the smart device is located up to 20m away from the speaker, it is possible to detect the sending direction of the signal. We confirmed the possibility of the proposed technology in 8kHz and 20kHz signal detection by smart device.

• Fire Science and Engineering
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• v.25 no.5
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• pp.100-107
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• 2011

In this study, a simulated situation in which the visions of the evacuees were blocked by the smoke, which is one of the most dangerous factors that cause casualties in case of an emergency, was conducted for the evaluation of the performance of an evacuation guidance system. For this purpose, the behavior and time taken by the experiment subjects in simulated evacuation test were measured and analyzed. When the evacuation guidance sound signals were given by 4 speakers at the same time, most of the subject were disoriented and took generally longer in getting to the pre-designated evac point. And, using only one speaker instead of two showed a better result in terms of the evacuation behavior or and orientation. Also, when there were two or more speakers used for the broadcasting of the guidance message, it turned out that using Hass effect, and placing the speakers closer, could result in higher awareness of the guidance message and maintenance of the orientation, while it also made the subjects took short to get to the evac point.