• Journal of the Society of Disaster Information
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• v.17 no.1
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• pp.184-193
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• 2021

Purpose: In this study, since the operation principle of the CCFL Exit light is the same as that of general lighting equipment, the characteristics of the CCFL Exit light were analyzed by deriving test items that can affect the characteristics of the light source from the KS standard, which is the standard for lamp ballast performance certification of general lighting equipment. Method: The samples used in the experiment were performed on products of two manufacturers for each size, such as large, medium, and small, and the test items were power factor, crest factor, and current harmonic distortion. Result: As a result of the experiment, the power factor showed a value between 0.4 and 0.6 in all samples, which was smaller than the 0.9 value set by KS. The crest factor ranged from 3.6 to 3.7 for large, 4.4 to 4.7 for medium, and 3.5 to 3.7 for small. It showed a value more than two times higher than the KS standard of 1.7. Current total harmonic distortion ranged from 81% to 110%, and considering that the KS standard was less than 20%, it could be confirmed that all samples had a value significantly exceeding the KS standard. Conclusion: The crest factor and current total harmonic distortion may affect the temperature rise of the light source and the burnout of the device. When developing an exit light, if this item is developed within the scope of the KS standard, the quality improvement and maintenance of the exit light will be greatly improved.

• Journal of the Society of Disaster Information
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• v.19 no.1
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• pp.138-145
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• 2023

Purpose: In accordance with the increase in the number of buildings repaired and reinforced following deterioration from when a fire occurs in a previously reinforced building, the impact on the structure after the fire is analyzed to establish standards for repair and reinforcement measures. Method: After curing for 28 days, the process was to measure the compressive strength and induce destruction through a compressor, repair and reinforce it with epoxy, and conduct a re-compressive strength test on some specimens after curing for 3 days to understand the degree of strength restoration. The rest of the repaired and reinforced specimens as well as the unrepaired and unreinforced specimens were then put into an oven and heated according to the temporal and temperate conditions listed below, and then the compressive strength was tested to estimate the impact of fire. Result: After reinforcing the yielded specimen with epoxy, the process was to then put it in an oven and heat it at different temperatures over time. It was found that there was a decrease in the strength of the reinforcement more than that of the actual specimen. Conclusion: Based on this, it was found that a building repaired and reinforced with epoxy resin is actually more dangerous than a general unrepaired building when it is damaged by fire, and thus, that it must be prepared for fire vulnerabilities.

• Journal of the Society of Disaster Information
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• v.20 no.2
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• pp.329-338
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• 2024

Purpose: This study verified the safety of the improved box-type girder behavior by comparing and evaluating the bending behavior results of a full-scale specimen based on the analytical behavior of the splice element PSC U-shaped girder with integrated tensioning systems. Method: Based on the results of the service and strength limit state design using the bridge design standard(limit state design method), the applied load of a 40m full-scale specimen was calculated and a static loading experiment using the four-point loading method was performed. Result: When the design load, crack load, and ultimate load were applied, the specimen deflection occurred at 97.1%, 98.5%, and 79.0% of the analytical deflection value. When the design load, crack load, and ultimate load were applied, the crack gauge was measured at 0.009~0.035mm, 0.014~0.050mm, and 6.383~5.522mm at each connection. Conclusion: The specimen behaved linear-elastically until the crack load was applied, and after cracks occurred, it showed strainhardening up to the ultimate load, and it was confirmed that the resistance of bending behavior was clearly displayed against the applied load. The cracks in the dry joints were less than 25% of grade B based on the evaluation of facility condition standard. The final residual deformation after removing the ultimate load was 0.114mm, confirming the stable behavior of the segment connection.

• Journal of Internet Computing and Services
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• v.17 no.5
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• pp.17-23
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• 2016

Wireless sensor-actuator networks (WSANs) enhance the existing wireless sensor networks (WSNs) by equipping sensor nodes with an actuator. The actuators work with the sensor nodes and perform application-specific operations. The WSAN systems have several applications such as disaster relief, intelligent building, military surveillance, health monitoring, and infrastructure security. These applications require capability of reliable data transfer to act responsively and accurately. Biologically inspired modeling techniques have received considerable attention for achieving robustness, scalability, and adaptability, while retaining individual simplicity. In this paper, an epidemic-inspired algorithm for data dissemination with delay constraints while minimizing energy consumption in WSAN is proposed. The steady states and system stability are analyzed using control theory. Also, simulation results indicate that the proposed scheme provides desirable dissemination delay and energy saving.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.4
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• pp.373-387
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• 2016

The citizen is going to live on security for better life stably in all times, and, as for such human basic desire, it is to the base which is important about the durability and the development of the smart city. I defined needs and the priority about the disaster recovery of the community as a citizen through date analysis until I came back to the normal environment again after a smart city suffered the damage by the misfortune in the study. I was going to suggest a method to support inhabitants of the damage area that was the immediate, and was necessary for a base in such date analysis and recovery of the community. I considered the Great East Japan Earthquake in an example in 2011. I studied the smart city plan which could improve the resilience of the local citizen and community through data utilization.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.9
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• pp.1808-1815
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• 2016

Stable operation of the dam and the river is directly related to the life and property of citizens, and hydrological observation data reliability is essential to the safety against disaster. Even though real-time data acquisition with high accuracy is needed for scientific and reliable water resources management, currently operating water gauges installed on the upper and down stream of dams or rivers are not easy to be calibrated or corrected on site to ensure higher reliability. K-water Institute has been operating an international accredited calibration laboratory for flows meters, rainfall and water gauges. Rainfall gauges are calibrated in the fixed standard room or on-site. However, due to the absence of on-site calibration procedure and system, on-site calibration for the water gauges are performed by an external agency. Therefore, a development of standard calibration procedure and system for on-site calibration of water gauges is needed to improve the reliability of observed hydrological data.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.595-597
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• 2018

Precipitation has a wide range of applications, such as the management and operation of dams and rivers, supply of dranking water for urban and industrial complex, farming and fishing, forest greening, and safety management. In order to prepare for disasters and to obtain economical effects in case of flood damage, it is necessary to measure accurate precipitation. In this study, we carried out the characteristics tests for various types of rainfall gauge using integrated verification system, which can analyze the performance of collective type rainfall gauge. The uncertainty for tipping bucket rain gauge was 0.2887 mm. Therefore, it can be seen that the uncertainty is calculated differently depending on the characteristics of the rainfall gauges. The uncertainty is also influenced greatly by the resolution.

• Journal of Internet Computing and Services
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• v.10 no.5
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• pp.13-26
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• 2009

Wireless Sensor Networks (WSNs) is one of the key technologies that make it possible to provide u-service in a ubiquitous society, however, it has disadvantages such as difficulty of managing sensor nodes and weaknesses of stability or mobility in large-scale WSNs. In order to solve these problems, 6LoWPAN that integrates with WSNs and IP networks has been studied widely. In this paper, we propose a Location Tracking Service Based on Google Map (LTSGM) system using 6LoWPAN. Since LTSGM system provides visual location information of sensor nodes through Google Map, it is possible to makes it easier than ever to manage sensor nodes in large-scale WSNs. Moreover, LTSGM can be used for various services such as applications for disaster or crime because it can trace the location of mobile nodes. Implementation of LTSGM system will be a test platform for 6LoWPAN.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.27 no.1
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• pp.62-68
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• 2023

An aerial relay system utilizing an unmanned aerial vehicle(UAV) or drone is addressed for event-driven operations such as temporary communication services for disaster affected area, military and first responder support. UAV relay system (URS) targets to provide a reliable communication service to a remote user equipment or an operator, therefore, a fast UAV placement to guarantee a minimum quality of service(QoS) is important when an operation is requested. Researches on UAV utilization in communication systems mostly target to derive the optimal position of UAV to maximize the performance, however, fast deployment of UAV is much more important than optimal placement under emergency situations. To this end, this paper derives the feasible area for UAV placement, investigates the effect of performance requirements on that area, and suggests UAV placement to certainly guarantee the performance requirements. Simulation results demonstrate that the feasible area derived in this paper matches that obtained by an exhaustive search.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.1101-1104
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• 2021

최근 COVID-19(코로나 바이러스 감염증) 확산에 따라 다양한 분야에서 힘든 상황이 이어지고 있다. 중앙 재난 안전 대책본부에 따르면 지난 2월 한 달간 코로나 안전신고는 약 2만 5천 건의 방역수칙 위반 신고가 들어온 것으로 집계됐다. 이에 따라 음식점 및 매장은 QR코드. 수기 작성을 통한 동선 체크, 온도 검사 등 코로나 확산을 방지하기 위한 방법을 시행하고 있지만 이는 단지 코로나 확산 방지를 위한 대책 일뿐 소상공인의 매장 운영이나 안정적인 영업 유지 등 직접적인 영향을 줄 수 없다. 이에 본 논문은 OpenCV를 활용한 고객 출입 관리 시스템을 제안한다. 본 시스템은 OpenCV 영상처리기술을 활용하여 매장을 방문하는 고객의 나이, 성별을 수집하여 주요 고객층 분석, 출입 현황 및 이용 시간을 파악한다. 본 시스템은 코로나 확진자 동선 파악을 위한 역학조사와 소상공인의 효율적인 매장 운영 시간을 분석하여 '코로나 확산 방지', '소상공인 매출 증가'의 기대 효과를 얻을 수 있다. 향후, 제안하는 기법의 실질적인 검증을 위해 실제 매장 환경에서의 테스트가 필요하다.