• TTA Journal
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• s.173
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• pp.106-109
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• 2017

LED 조명의 가시광에 데이터를 담아 보내는 가시광 통신(VLC) 기술 특허출원이 2009년 이후 가파르게 상승하고 있는 추세이다. 빛(Light)과 와이파이(Wi-Fi)를 합쳐 이른바 라이파이(Li-Fi, Light Fidelity)라고도 부르는 이 기술은 백만 분의 1초 간격으로 LED 조명을 켜고 끄는 것을 반복하여 데이터를 교환한다. 국내에서는 (주)유양디앤유가 2013년 이마트와 협력해 쇼핑 관련 VLC 기술을 적용한 시범 사업을 한 바 있다. (주)유양디앤유는 VLC 기술의 노하우를 바탕으로 미래 기술로 각광받고 있는 IoT를 접목해 사업을 다각화하고자 하였다. 이를 위해, 관련된 특허를 개발하고 국제 표준으로 제안하기 위해 TTA에 도움을 요청했다. TTA는 자문서비스와 함께 표준특허 인큐베이팅 사업을 연계하여 (주)유양디앤유를 지원하였다. 이를 통해 IoT를 접목한 VLC 무선 통신 국내 특허와 PCT 국제출원이 동시에 진행되는 성과를 거두었다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.6
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• pp.375-381
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• 2019

Structural health monitoring to determine structural conditions at an early stage and to efficiently manage the energy requirements of buildings using systems that collects relevant data, is under active investigation. Structural monitoring requires cutting-edge technology in which construction, sensing, and ICT technologies are combined. However, the scope of application is limited because expensive sensors and specialized technical skills are often required. In this study, a Raspberry Pi module, one of the most widely used single board computers, a Lora module that is capable of long-distance communication at low power, and a high-performance accelerometer are used to construct a wireless edge computing system that can monitor building response over an extended time period. In addition, the Raspberry Pi module utilizes an edge computing algorithm, and only meaningful data is obtained from the vast amount of acceleration data acquired in real-time. The raw data acquired using Wi-Fi communication are compared to the Laura data to evaluate the accuracy of the data obtained using the system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.11
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• pp.2143-2148
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• 2016

Recently due to development of IT technology, ideas and technology that blend with environment have evolved. This technology can help people's living environment and in the future it is an essential component of the connected society. In this paper, we propose WiT(WiFI Trashcan) which takes advantage of the IT technology fusion and environmental factors at the same time to create a more pleasant environment. WiT provides a free WiFi when trash is disposed in the trash can. WiT detects whether a user disposes trash, determines the volume of the trash and provides free WiFi. To detect trash we use ultrasonic sensor and trash weight is measured by using weight sensor. Also by using Phython programming the measured sensor value is transmitted to Raspberry Pie and WiFi delivery time is determined. We used Arduino and Raspberry Pi to design and implement WiT.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.1
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• pp.17-28
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• 2014

The increase of smartphone users have made mobile carriers offload increasingly congested traffic of 3/4G by providing Wi-Fi hot-spots in the public places such as coffee shops and subway stations. In the traditional authentication in WLAN, the users should convince the service providers that they are valid customers before they use WLAN services. Since the authentication protocol is designed for service providers. Even with the mutual authentication based on the IEEE 802.1X, which is supported by IEEE 802.11 standard, it is difficult to be convinced of that the service providers really have installed the WLAN APs, which users are confronted with. An attacker can install rogue APs that masquerade as legitimate APs by copying the SSID, MAC address, etc. in order to obtain users' private information. In this paper, we introduce a method of authenticating legitimate APs for smartphone users. And we show our proposal can be well utilized for the current Wi-Fi hot-spots as a security plug-in and prove it through our experiments.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.3
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• pp.465-470
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• 2017

This paper designs and implements a smart garden system using probabilistic filter algorithm using SLAM that can be used in apartment or veranda. To do this, we used Arduino and environtal sensors, which are open hardware controllers, and designed to control and observe automatic water supply, lighting, and growth monitoring with three wireless systems (Bluetooth, Ethernet, WiFi). This system has been developed to make it possible to use it in an indoor space such as an apartment, rather than a large-scale cultivation system such as a conventional plant factory which has already been widely used. The developed system collects environmental data by using soil sensor, illuminance sensor, humidity sensor and temperature sensor as well as control through smartphone app, analyzes the collected data, and controls water pump, LED lamp, air ventilation fan and so on. As a wireless remote control method, we implemented Bluetooth, Ethernet and WiFi. Finally, it is designed for users to enable remote control and monitoring when the user is not in the house.

• Journal of Digital Convergence
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• v.14 no.10
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• pp.415-421
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• 2016

There has been an enormous increase not only in the international economic exchanges but also in the cultural exchanges. However, studies to settle the cultural differences have been studied a lot with in economic and business partial but research of eliminating cultural differences for travelers has not been studied. Therefore, in this study, we tried to develop the service design to eliminate the cultural differences. To set the spatial range, we choose airport which can be the hub and the door of the travelers at the same time. Moreover, we tried to understand the meaning of communication and sharing to resolve differences in culture through literature studies. Further, we analyzed the airport application and examples of Wi-Fi linked services, so can be applied to the proposal. Travelers share the cultural differences by themselves; through the Wi-Fi service in the airport, and the existing airport application. We expect to be able to resolve the cultural differences between nations and develop not only their prosperity but also the national image by this service.

• Journal of Satellite, Information and Communications
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• v.11 no.4
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• pp.33-38
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• 2016

As a communications system and using the wireless devices is increased at the world, the interference among devices at 2.4GHz band become issue. New complex content technology as education, concert, broadcast, thema-park are developed between Virtual Reality technology and tradition. That is expect an annual growth rate of more than 14%. Almost Virtual Reality devices use motion sense or a wireless joystick. Therefore it is necessarily to analyze the coexistence between Virtual Reality devices and Wi-Fi in the ISM band. The interference scenario and propagation of the Extended Hata Model was established to analyze the interference from WLAN into Virtual Reality devices. Through simulation results based on Monte-Carlo principle, separation frequency was obtained to protect WLAN interference from Virtual Reality devices.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.6
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• pp.1113-1120
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• 2022

In this paper, a communication methodology for the digital FRTU(: Feeder Remote Terminal Unit) required by the smart grid distribution system was studied. The digital FRTU consists of a fault handling unit and a communication unit. The fault handling unit transmits fault information to the communication unit in case of a failure, and the communication unit is designed to autonomously determine the fault section through two-way communication between surrounding digital FRTUs. For performance verification, a performance verification system consisting of 3 line sections based on 3 digital FRTUs was constructed to enable fault simulation for various failure scenarios. Various fault cases including one phase ground fault, line-to-line short-circuit fault, and three-phase short-circuit fault were experimentally simulated on the established performance verification system, and the validity of the developed methodology was confirmed by proving the accurate fault section inference results for each fault simulation case.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1019-1024
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• 2019

In this paper, we plan to design and manufacture a new sleeping child check system using image and PIR sensors. Therefore, it plans to implement a system that can prevent in-vehicle accidents that can occur due to presence of human and certain temperature inside the vehicle by collecting data from PIR sensors and temperature sensors with the main control device based on Arduino. In addition, the values of sensors can be linked with Bluetooth communication or Wi-Fi communication to send information to the mobile phone, and the sensor values can be printed by texting on the screen. It also plans to use raspberry pie and camera modules to build a display and smartphone streaming service inside the vehicle. Through this, the objective of this study is to prevent safety accidents in school vehicles by making experiments and research in this paper recognize 100% inside the vehicle with the quantitative goal of PIR sensors.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.157-162
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• 2018

This study uses sensors and Raspberry Pi to measure the values of current and voltage and transmits the measured sampled values to a network, carrying them in the frame of IEC 61850-9-2. A laboratory model was composed to send the sampled values, using the frame of IEC 61850-9-2. This study conducted a protocol analysis, using Wireshark for the accurate verification of the occurrence of the frame of IEC 61850-9-2. A visual analysis was conducted by displaying the received sampled values of current and voltage on the monitor in graphs. In addition, this study tested if the sampled values of IEC 61850-9-2 sent and received through the network equipment would meet the performance requirements of the message types of IEC 61850.