• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.1-7
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• 2021

This study attempted to detect possible collapse and fire accidents in facilities for disaster monitoring of large facilities, and to develop a customized beacon to recognize the internal situation of an IoT-based facility when a disaster occurs. In the case of data measurement using the existing strain gauge sensor, the strain gauge sensor was connected by wire to measure it, but this study changed it to wireless so that the presence and absence of structural deformation can be monitored in real time. In this process, in order to use the Wheatstone bridge, a strain sensor module that can be connected to a customized beacon was manufactured, and a system configuration was conducted to remotely check the measurement data. To verify measurement data, 10 customized beacons and 2 gateways were installed on the 15th floor of the Advanced Institue of Convergence Technology, and as a result of analysis of measurement data, it was confirmed that the strain data values were distributed between 7 and 8.

• Journal of the Korea Society of Computer and Information
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• v.28 no.3
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• pp.11-16
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• 2023

As techniques for indoor positioning, fingerprinting, indoor positioning method using trilateration, and utilizing information obtained from equipments by Wi-Fi/Bluetooth, etc are common and representative methods to specify the user's indoor position. However, in these methods, an indoor space should be provided with enough space to install a large number of equipment (AP, Beacon). In this paper, we propose a technique that can express the user's location within a building by simultaneously using the GPS signal and the signal transmitted from the beacon in a building structure where the conventional method cannot be applied, such as a narrow building. A shortest path search system was designed and implemented by applying the Dijkstra Algorithm, one of the most representative and efficient shortest path search algorithms for shortest path search. The proposed technique can be considered as one of the methods for measuring the user's indoor location considering the structural characteristics of a building in the future.

• Journal of the Korea Society of Computer and Information
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• v.23 no.12
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• pp.145-151
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• 2018

While commercialization of IoT technologies in the safety management sector is being promoted in terms of industrial safety of large indoor businesses, implementing a system for risk management of small outdoor work sites with frequent site movements is not actively implemented. In this paper, we propose an efficient dynamic workload balancing strategy which combined low-power, wide-bandwidth (LPWA) communication and low-power Bluetooth (BLE) communication technologies to support customized risk management alarm systems for each individual (driver/operator/manager). This study was designed to enable long-term low-power collection and transmission of traffic information in outdoor environment, as well as to implement an integrated real-time safety management system that notifies a whole field worker who does not carry a separate smart device in advance. Performance assessments of the system, including risk alerts to drivers and workers via Bluetooth communication, the speed at which critical text messages are received, and the operation of warning/lighting lamps are all well suited to field application.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5A
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• pp.457-465
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• 2010

When a sensor network is used for monitoring environments in large area or transmitting information in a u-City the number of nodes becomes very large. One of the problems with this application is the increased time delay, especially in reverse direction. In this paper, we propose a new algorithm that can minimize the latency of reverse packet in large sensor network. Analysis shows that the proposed scheme can reduce the latency by more than 90% when compared to Zigbee, while the energy consumption is maintained.

• The Journal of the Korea Contents Association
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• v.19 no.7
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• pp.192-198
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• 2019

We propose an emergency rescue support communication system to quickly rescue passenger ships, such as large cruise ships, when a ship sinks or a disaster such as a fire occurs. A beacon is installed in the inside of the vessel, and the position and the status of the passenger are detected in real time through the Bluetooth communication in the mobile terminal carried by the passenger and transmitted to the server. When an emergency occurs, the server sends information on the passenger to the rescue agency, informs the passenger of the emergency, and guides evacuation. As a result of simulations using the designed system, it was confirmed that the server immediately notifies all terminals when an emergency occurred in more than half of the area. This system, which detects the accident in real time and notifies all terminals in the vessel, unlike the existing system that notifies the position of the accident vessel or simply the position of the passenger in the vessel, will be helpful for the rapid evacuation and rescue of the passenger.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.777-785
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• 2021

Many utility lines are buried underground to provide various functions of the city. Because historical records are not managed systematically, damage has occurred during excavation. In addition, the demand for an underground facility management system is increasing as the aerial underground project is progressing. By attaching an electronic recognition sensor to an underground facility, such as pipelines, the management history and site conditions can be carefully managed. Therefore, in this study, electronic recognition sensors, such as BLE Beacon, UHF RFID, geomagnetic sensor, and commercial marker, were tested to analyze the strengths, weaknesses, and field applicability through a pilot project. According to the limited research results collected through two pilot projects, the installation depth is most important to demonstrate the performance of the electronic reader. In addition, because it should be used in urban areas, the influence of environmental interference should be minimized, and there should be no performance degradation over time. In the case of the geomagnetic recognizer, the effect of environmental interference was large, and performance degradation occurred over time using the BLE Beacon. In the field situation, where the installation depth can be controlled to less than 40cm, the utility of the battery-free UHF RFID was the best.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.7
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• pp.1262-1268
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• 2016

Bluetooth has been developed to be applied over the course of several versions in different environments. Especially low is moving to address the constraints, it gives a high utilization rate is faster than the Zigbee wireless LAN communication. To gather information on children's environmental copper transition to multiple versions. There is one limitation of Bluetooth requirements to effectively apply the information collected by Bluetooth. At the same time need to collect several information actions, Bluetooth can not connect to one of only seven Slave Master. In this paper, in order to take advantage of the many benefits of Bluetooth to gather the information by operating the Bluetooth operates in Beacon deliver packets of 168 bits, and the pairing between the master and slave unnecessarily generate a regular signal a large number of connections simultaneously Information We consider how to apply the effective policy that can be collected.

• Journal of Digital Policy
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• v.2 no.4
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• pp.11-15
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• 2023

Recently, a fire suddenly broke out in a crowded theater, and many people were unable to find an escape route, becoming entangled, injured, and suffocating from smoke inhalation, resulting in a large-scale fire accident. Even though most of the people were young, they were unable to evacuate. If they had been elderly, it could have resulted in greater casualties. In particular, since it is difficult to receive accurate location information from GPS indoor, there is an urgent need for location-based services using beacons and an emergency evacuation system that intuitively shows evacuation routes in augmented reality using smart-phones. In this paper, an augmented reality-based emergency evacuation smartphone app was developed based on identifying fire locations and evacuation routes using beacons and fire sensors (IoT). In the future, if the proposed system is applied to indoor spaces where people are crowded, rapid evacuation will be possible even in a sudden fire accident, minimizing human damage.

• Journal of the Korean Institute of Navigation
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• v.24 no.5
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• pp.405-415
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• 2000

DGPS/Radio beacons are currently being planned or installed in many countries. They offer a cost-effective way of distributing differential data to large number of users. These networks are also being deployed in South Korea, Japan, and China. Several DGPS stations among them are operating on the same frequencies. The DGPS signal based on a radio beacon in medium frequency band travels principally as a groundwave over the surface of the earth. The signal may also be received as skywaves at locations beyond about 100 km from the reference station. These skywaves interfere with groundwave signals due to fading. This factor has generally ignored in designing DGPS/Radio beacon systems. A further important factor is to reduce the coverage due to interference from other beacons on the same or adjacent frequencies. The desired signal may fade due to interaction between its skywave and groundwave components. It may degrade the accuracy of the positioning in a complex fashion. This paper estimates the coverage of Far East Asia DGPS stations which are operating on the same frequencies, which is based on the signal protection ratio and interference of the signal strength of the groundwave and skywave.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.10
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• pp.4971-4987
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• 2019

Node localization is the basic task of underwater wireless sensor networks (UWSNs). Most of the existing underwater localization methods rely on ranging accuracy. Due to the special environment conditions in the ocean, beacon nodes are difficult to deploy accurately. The narrow bandwidth and high delay of the underwater acoustic communication channel lead to large errors. In order to reduce the ranging error and improve the positioning accuracy, we propose a localization algorithm based on ranging correction and inertial coordination. The algorithm can be divided into two parts, Range Correction based Localization algorithm (RCL) and Inertial Coordination based Localization algorithm (ICL). RCL uses the geometric relationship between the node positions to correct the ranging error and obtain the exact node position. However, when the unknown node deviates from the deployment area with the movement of the water flow, it cannot communicate with enough beacon nodes in a certain period of time. In this case, the node uses ICL algorithm to combine position data with motion information of neighbor nodes to update its position. The simulation results show that the proposed algorithm greatly improves the positioning accuracy of unknown nodes compared with the existing localization methods.