• Journal of Internet of Things and Convergence
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• v.3 no.1
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• pp.13-19
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• 2017

In this paper, we designed and implemented Thing Connected-Green, a self-installing agricultural automation system capable of remote monitoring and control based on Low Power Wide Area communication technology (LPWA). Farming requires water, sunlight, soil, fertilizer, temperature control, etc., and these elements can be remotely monitored and controlled using an automated system. Using this system, it is possible to construct an agricultural automation system which can be optimized according to the kind of plant and cultivation environment from vinyl house to flower garden. The information gathered from the sensor is stored in the server through the gateway, and the optimal cultivation environment can be set and operated using the smart phone based on the big data.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.569-570
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• 2018

Recently, Although particulate matter monitoring has been attracting attention as a result of social attention to the human impact of particulate matter, data suitable for the residential environment can not be obtained due to imbalances in the installation of monitoring stations and differences in topography. In this paper, we propose LoRa LPWA-based particulate matter measurement system which can make long distance wireless communication to measure particulate matter in residential environment. In the proposed system, it is possible to collect the data of the external environment which is difficult to construct the internet by utilizing LPWA which is a long distance wireless communication technology. When the proposed system is applied to the residential environment, it is expected to provide particulate matter monitoring information suitable for the residential environment.

• Journal of the Korea Society of Computer and Information
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• v.25 no.7
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• pp.85-92
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• 2020

Following the development of Internet of Things (IoT) technology, the scope of application of IoT technology is expanding to industrial safety areas that detect and prevent possible risks in outdoor environments in advance, away from improving the convenience of living in indoor environments. Although this expansion of IoT service provides many advantages, it also causes security problems such as data leakage and modulation, so research on security response strategies is being actively carried out. In this paper, the IoT-based road construction risk management system in outdoor environment is proposed as a research subject. As a result of investigating the security vulnerabilities of the low-power wide-area (LPWA, BLE) communication protocol applied to the research targets, the security vulnerabilities were identified in terms of confidentiality, integrity, and availability, which are the three major elements of information security, and countermeasures for each vulnerability were proposed. This study is meaningful in investigating and analyzing possible vulnerabilities in the operation of the IoT-based risk management system and proposing practical security guidelines for each vulnerability.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.1
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• pp.55-61
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• 2020

Social infrastructure facilities that have been under construction since the country's high-growth period are undergoing rapid aging, and, thus, safety assessments of large structures such as bridge tunnels, which can be directly linked to large-scale casualties in the event of an accident, are necessary. It is difficult to construct economical and efficient wireless smart sensor networks that improve structural health monitoring (SHM) because the existing wire sensors have a short signal reach. However, low-power wide-area networks (LPWANs) are becoming popular within the Internet of Things, and enable economical and efficient SHM. In this study, the technology trends of a wireless measuring sensor based on LoRa LPWANs were investigated, and an installation and maintenance plan for this type of sensor is proposed.

• Korean Institute of Interior Design Journal
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• v.25 no.4
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• pp.68-79
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• 2016

The purpose of this study is to provide a reference for stage space planning in modern theaters by analyzing and understanding stage components in terms of spatial composition, purposes, and correlation between them, and collecting various opinions from stage managers an directors. The findings are as follow: the determination of the size of proscenium arch is crucial, and it needs to be considered not only with the genre of the performance and the number of seats, but also with the size of the stage facility. The two-dimensional size of proscenium arch affects the scale of stage area in three-dimensional way; the size of main stage comes from the width of the arch, and the length of set battens comes from the stage width, and so on. The height of the arch affects the elevation of gridiron, and the height of the building itself ultimately. The number and length of the set battens are directly linked to the size of the winch room, and so is the number of the winches to the Mcc panel room. The 1st level gallery supplying power to lighting equipment needs to be wide enough for staffs to work with various equipments effectively and safely. Degree of practical usage of under-stage machinery turned out to be very low. In order to cut unnecessary waste and cost, the characteristics of the theater must get set first, and experts who know how stage works need to get involved in planning stage.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.2
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• pp.113-119
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• 2017

In this paper, we have shown the performance analysis results of the LoRa low power wide area network under duty cycle local regulation in Korean RFID/USN frequency band. Especially, we analyzed uplink throughput and data transmission time of a single LoRa end device. From the analysis results, duty cycle regulation, in which a data transmission should be ended within 0.4 second, limits the performance of LoRa network. Therefore, it is necessary to revise Korea's duty cycle regulation referencing EU regulation in order to assess LoRa network in Korea.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.6
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• pp.897-906
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• 2022

In this paper, we propose a novel MAC protocol based on the harmonic transmission of ACK, called HAT-LoRa, for improving the reliability and the utilization in multiple gateway LoRa Networks. LoRa is basically vulnerable to collision due to the primitive pure ALOHA-like MAC. Whereas data frame delivery can be guaranteed by the transparent bridge of multiple receiving gateways, ACK is still transmitted by a single gateway in LoRa Network. HAT-LoRa provides the augmented reception opportunity of ACK via the simultaneous transmissions of identical ACK in multiple spreading factors. The proposed method reduces the expected transmission times of ACK double gateway environment as well as single gateway environment, by 55 and 60% in maximum, by 35% and 40% in average, in a single- and double-gateway environment, respectively. Especially, it outperforms under the environment where the distance between end device and gateways are similar to each other.

• Journal of Convergence for Information Technology
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• v.12 no.4
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• pp.1-8
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• 2022

With the development of communication infrastructure, the number of network equipment owned by one person is gradually increasing. General-purpose devices such as smartphones can implement theft/loss prevention function by implementing S/W. However, other small devices lack practicality such as long-distance communication problems due to standard communication technology specifications or H/W limitations, and lack of functions(authentication and security). This study combines the Lora communication protocol in the LPWA standard environment and the blockchain technology. Anti-theft and security functions were added to the protocol, and the PBFT consensus algorithm was applied to build a blockchain network. As a result of the test, the effectiveness of safety(authentication and trust network) and performance(blockchain processing performance) were confirmed. This study aims to contribute to the future development of portable or small device anti-theft products as a 4th industrial convergence research.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.1
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• pp.49-56
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• 2023

With the development of technology worldwide, bridges are becoming larger, and the number of old bridges is also rapidly increasing. Monitoring the structural health of large, aging bridges is essential to preventing large-scale accidents. In this study, the application of a LoRa low-power wide-area network (LPWAN)-based wireless measurement system was investigated, and a LoRa wireless measurement system was established in the cable-stayed bridge section of Cheonsa Bridge, located in Shinan-gun, Jeollanam-do, Korea. The applicability of the LoRa LPWAN-based wireless monitoring system to large marine bridges was reviewed by comparing the performance and economic feasibility with wire-based monitoring systems that were built and operated by establishing a measurement system for the pylons, cables, and reinforcing girders of the bridge.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2158-2165
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• 2023

Marine radioactivity monitoring is critical for taking immediate action in case of unexpected nuclear accidents at nuclear facilities located near coastal areas. Especially when the level of contamination is not predictable, mobile monitoring systems will be useful for wide-area ocean radiation survey and for determination of the level of radioactivity. Here, we used a silicon photomultiplier and a high-efficiency GAGG crystal to fabricate a compact, battery-powered gamma spectroscopy that can be used in an ocean environment. The developed spectroscopy has compact dimensions of 6.5 × 6.5× 8 cm³ and weighs 560 g. We used LoRa, a low-power wireless protocol for communication. Successful data transmission was achieved within 1.4 m water depth. The developed gamma spectroscopy was able to detect radioactivity from a ¹³⁷Cs point source (3.7 kBq) at a distance of 20 cm in water. Moreover, we demonstrated an unmanned radioactivity monitoring system in a real sea by combining unmanned surface vehicle with the developed gamma spectroscopy. A hidden ¹³⁷Cs source (3.07 MBq) was detected by the unmanned system at a distance of 3 m. After successfully testing the developed mobile spectroscopy in an ocean environment, we believe that our proposed system will be an effective solution for mobile real-time marine radioactivity monitoring.