• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.8
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• pp.571-575
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• 2018

The moisture content of a coffee bean affects its permittivity, and changing the moisture content of a coffee bean changes the taste of the coffee. The variation in the moisture content of a coffee bean can be predicted by the change in frequency and reflection coefficient values with respect to the variation in the permittivity of the bean when it is placed on a patch antenna. In this study, a dual-band patch antenna is designed, which has a moisture measurement band of 3.8~4 GHz that can measure the moisture level of a material; the antenna has a Wi-Fi transmit and receive band of 2.45 GHz. Through simulations and measurements, this study proved that the level of return losses changed from 3.6 to 4 GHz when the moisture content of a coffee bean changed from 2 to 15%. The moisture levels of rice and other beans can be measured with the designed antenna, which can be applied to various applications.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.221-227
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• 2014

This paper presented a design which was a minimized remote control robot. This remote control robot was created for preventing life damage from conflagrations, nuclear events and HF gas accidents. This robot's system based smart phone that had camera and GPS systems. When fire came out, The robot figured out that how big fire was, where the fire was started and various aspects of situations. And The robot broadcasted the informations to smart phone using mobile application and wi-fi camera. By doing these, the fire mans could more accurate and be easier to plan a strategy for saving life. The body of robot are 2 parts. One is a car and the other one is a remote controller. By the power, 1step to 10steps, of grabbing remote controller could change the car's speed to move. Also, The prototype robot was already confirmed its utility itself.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.6
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• pp.203-209
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• 2017

Low birth rates and aging problems are raising a big issue in the worldwide. Recently, Korea also has no one to caring children who have low discernment and old ones who have Alzheimer's disease because of growing nuclear families and dual income furnitures. Therefore many serious crimes like kidnappings were occurred by people who have mental problems or bad intentions. Even though missing and ding alone are increasing together. The result of it, the needs of potable GPS system, to tracking for the olds and week ones, is highly growing nowadays. This paper introduce producing prototype tracker, looks like fashion accessories, which is using GPS, Zigbee and WiFi. It expects developing many accessory types of trackers effectively helps protect children and old ones from kidnappers at a low cost in this aging society.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.103-107
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• 2019

As the number of foreign tourists increases worldwide, it provides tourism services with various information and convenience. Most foreign tourists have difficulty using existing methods that require internet connection because internet communication is restrictive. In this paper, we propose a mobile device based digital signage via WPAN that can support multi-lingual for foreign tourists. the proposed method shows a menu by combining a template of mobile client with fundamental contents from digital signage through WPAN. To evaluate the performance of the proposed method, it is compared with a conventional webpage method. The results of the evaluation confirm that the latency decreases compared to the conventional webpage method due to the improved loading time.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.6
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• pp.589-592
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• 2015

In this paper, we suggested a real-time test-bed for analyzing frequency interference between 2.4 GHz unlicensed devices, such as WiFi, Zigbee, etc. Owing to versatile programming capability of Universal Software Radio Peripheral(USRP) and $Labview^{TM}$, frequency interference environments can be easily modeled. Therefore, performance degradation effects due to various parameters of interferer and victim receiver can be analyzed intuitively. For verification, we showed a frequency interference scenario, which consists of IEEE 802.15.4 as a victim and IEEE 802.11b as a interferer. Measured Bit Error Rate(BER) results showed good agreement with theory and simulation results.

• Journal of the Korean Magnetics Society
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• v.24 no.6
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• pp.179-185
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• 2014

The existing USB connection type of the clip-type pulsmeter equipped with a Hall sensor and a permanent magnet does not have any error or malfunction to measure the pulse wave. The property of the wireless networking system communicating the pulse wave data through the wireless LAN communication by combination USB with Ethernet and Ethernet to Wi-Fi converting system instead of existing USB connection method was investigated. There are exited that the patient needs to stay at close site of the desktop PC without USB connector and the wireless transfer and receiver networking system has pulse wave measurement SW to receive the pulse wave data. Thus it is expected that the study becomes helpful to measure and transfer the exact pulse wave of the patient in a comfortable pose at close range.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1405-1410
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• 2018

The Ringer's Solution used in medical institutions is one of the injections helpful for recovering the body condition from fever or dehydration by supplying the water to the body. The medical staffs frequently check the amount of Ringer's Solution prescribed for the relevant patient to check the time for replacing the Ringer's Solution. However, currently, many nurses experience the excessive workload because of the insufficient workforce and lots of workload assigned to each of the nurses; so the they cannot provide the high-quality medical services to patients and guardians. In order to solve this problem, this thesis designed and realized the Ringer's Solution replacement time control system through the non-contacting sensor, IoT device using WiFi, and OCS interlock. Thus, this study is expected to be able to efficiently operate the Ringer's Solution replacement work and also to provide the high-quality medical service to patients and guardians by automatically notifying the timing of Ringer's Solution replacement to medical staffs, and omitting the inefficient intermediate step in the past.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.6
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• pp.890-896
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• 2022

In this paper, gimbal camera control through smart gloves was implemented to increase convenience and accessibility to the control of drones used in various fields. Smart gloves identify human gestures and transmit signals through Bluetooth. The received signal is converted into a signal suitable for the drone through a GCS (Gound Control Station). Signals from smart gloves are expressed in a quaternion method to prevent gimbal locks, but for gimbal cameras, conversion is required to use Roll, Pitch, and Yaw methods. The data conversion mission is performed in the GCS. The GCS transmits an input signal to the control board of the drone through Wi-Fi. The control board generates and outputs the transmitted signal in a PWM manner. The output signal is input to the gimbal camera through the SBUS method and controlled. The input signal of the smart glove averaged 0.093 s and up to 0.099 s to output to the gimbal camera, showing that there was no problem in real-time use.

• 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.

• 정보화사회
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• s.181
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• pp.29-31
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• 2006

데이콤(대표 박종응 www.dacom.net)은 지난 5월 29일, 국내 최초로 무선 인터넷 전화 서비스인 와이파이(Wi-Fi)폰 서비스를 6월부터 일반 기업을 대상으로 상용화한다고 밝혔다.이 서비스는 기존 무선랜 환경을 기반으로 이동형 단말기인 Wi-Fi폰을 통해 구내.시내.시외.국제.이동전화 등을 제공하는 서비스. 기업내 구축돼 있는 무선랜스위치와 AP(Access Point)를 이용, 무선으로 VolP 서비스를 제공하는 방식이다. 데이콤에 따르면, 지금까지 070 등 유선을 기반으로 한 서비스 제공은 있었지만, 이동형 무선단말기를 통해 인터넷전화(VolP)서비스를 상용화하기는 이번이 처음이다. 지금까지 인터넷전화를 이용하기 위해선 별도의 070번호를 새로 부여받아야 했지만, 데이콤의 이번 와이파이 서비스는 시내번호 이동시 기존 시내전화 번호를 유지하면서 인터넷전화로 전환이 가능, 인터넷전화 서비스 활성화에도 큰 몫을 할 것으로 데이콤은 기대했다. 데이콤은 앞으로 $\Delta$무선랜 서비스를 이용 중이며, $\Delta$본.지사간 통화요금을 절감하고자 하는 기업$\Delta$IP기반의 사무실 환경개선을 희망하는 중대형 기업 $\Delta$호텔이나 병원, 대형 쇼핑몰처럼 선 없는 쾌적한 통신환경을 필요로하는 고객 중심으로 와이파이 서비스를 적극 확대해 나갈 계획이다.데이콤은 앞으로 Wi-Fi폰을 통해 음성 뿐 아니라 향후 영상 멀티미디어까지도 송수신 할 수 있는 서비스 개발에 박차를 가하기로 했다.