• Journal of IKEEE
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• v.16 no.1
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• pp.62-68
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• 2012

The planar microstrip antenna for the safety communication of life at sea is designed and manufactured to effectively receive the emergency wireless signal from the transmitter on the life vest. The proposed microstrip antenna in this paper is easy to make, light weight and cheap compared to other antennas because of printed antenna fabrication. To overcome the narrow bandwidth, large size and low gain characteristics of microstrip antenna, we use the IDMA(Identical Dual Patch Microstrip Antenna with Air-Gap) structure. The proposed antenna was fabricated with the use of 1.6mm FR4 and measured with the 28.7MHz(6.6%) of bandwidth and 3.04dBi of gain at the frequency of 426MHz. To validate the proposed antenna, we experimented the possible distance range at sea using the commercial UHF transceiver module and obtained over 5km distance for stable communication. This antenna can be widely applied to application of the UHF wireless mobile communication.

• Journal of the Korean Electrochemical Society
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• v.3 no.4
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• pp.241-245
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• 2000

The objective of this work Is to design, fabricate, and characterize pseudo-capacitor using amorphous $MnO_2\;nH_2O$ electrode material. The cyclic voltammogram under 100mV/s scan rate of the material shows the electrochemically stable potential window of 1V and the specific capacitance of 250F/g. The TDMA pulse test result indicates that the TDMA system (2 parallel-pseudo-capacitor systems) has the ohmic voltage drop of 0.22V and the capacitor voltage drop of 0.38V. The total voltage drop of the TDMA system is 0.60V and less than 1V of which value is the maximum voltage drop requirement or the TDMA satellite phone. Also, the TDMA system had the ESR of $55m{\Omega}$ and the capacitance of 105mF. Therefore, it is confirmed that the TDMA system has the application feasibility as load-leveling capacitor for the satellite phone.

• Journal of IKEEE
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• v.24 no.4
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• pp.1093-1097
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• 2020

This work describes the design and characterization of a Ku-band monolithic microwave integrated circuit (MMIC) power amplifier (PA) for satellite communication applications. The device technology used relies on 0.25 ㎛ gate length gallium arsenide (GaAs) pseudomorphic high electron mobility transistor (PHEMT) of wireless information networking (WIN) semiconductor foundry. The developed Ku-band PHEMT MMIC power amplifier has a small-signal gain of 22.2~23.1 dB and saturated output power of 34.8~35.4 dBm over the entire band of 13.75 to 14.5 GHz. Maximum saturated output power is a 35.4 dBm (3.47 W) at 13.75 GHz. Its power added efficiency (PAE) is 30.6~37.83% and the chip dimensions are 4.4 mm×1.9 mm. The developed 3 W PHEMT MMIC power amplifier is expected to be applied in a variety of Ku-band satellite communication applications.

• Journal of IKEEE
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• v.27 no.3
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• pp.225-233
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• 2023

This paper implements a system that monitors human body lifting information in the event of a marine accident. The monitoring system performs ultrasonic communication through a lifting device controller that transmits underwater environment information, and LoRa communication is performed on the water to provide GPS information within 10 km to the control center or mother ship. The underwater lifting controller transmits pneumatic sensor, gyro sensor, and temperature sensor information. In an environment where the underwater conditions increase by one atmosphere of water pressure every 10m in depth, and the amount of air in the instrument decreases by half compared to land, a model of a 60kg underwater mannequin is used. Using one 38g CO2 cartridge in the lifting appliance SMB(Surface Maker Buoy), carry out a lifting appliance discharge test based on the water level rise conditions within 10 sec. Underwater communication constitutes a data transmission environment using a 2,400-bps ultrasonic sensor from a depth of 40m to 100m. The monitoring signal aims to ensure the safety and safe human structure of the salvage worker by providing water depth, water temperature, and directional angle to rescue workers on the surface of the water.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1309-1316
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• 2018

Cattle estrus detection system based on Internet of Things is designed and implemented by using Arduino pro-mini, gyroscope, acceleration sensor, bluetooth master and slave module. The implemented system measures cattle's moving and the measured data are transmitted to the computer connected to RX module by bluetooth TX module. They are plotted in 2-dimensional graph on the computer monitor and the number of transition at each sensor axis are calculated from the graph. The detected and gathered data from the system are analyzed by the proposed algorithm to decide which cows are in the estrus or not. The method to apply bluetooth scatternet is shown and the proposed system can be used to increase the success rate of artificial insemination in normal estrus by detecting the cow's behaviors such as the number of jumping. In this paper, the implemented cattle behavior detecting the system(TX module) are strapped on cattle's leg and it measures the cattle behaviors for determining where that a cattle is estrus or not by the proposed algorithm.

• Journal of Appropriate Technology
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• v.7 no.2
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• pp.127-135
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• 2021

To respond to the threat of global warming, countries around the world are promoting the spread of renewable energy and reduction of carbon emissions. In accordance with the United Nation's Sustainable Development Goal to combat climate change and its impacts, global automakers are pushing for a full transition to electric vehicles within the next 10 years. Electric vehicles can be a useful means for reducing carbon emissions, but in order to reduce carbon generated in the stage of producing electricity for charging, a power generation system using eco-friendly renewable energy is required. In this study, we propose a smart electric mobility operating system integrated with off-grid solar power plants established in Tanzania, Africa. By applying smart monitoring and communication functions based on Arduino-based computing devices, information such as remaining battery capacity, battery status, location, speed, altitude, and road conditions of an electric vehicle or electric motorcycle is monitored. In addition, we present a scenario that communicates with the surrounding independent solar power plant infrastructure to predict the drivable distance and optimize the charging schedule and route to the destination. The feasibility of the proposed system was verified through test runs of electric motorcycles. In considering local environmental characteristics in Tanzania for the operation of the electric mobility system, factors such as eco-friendliness, economic feasibility, ease of operation, and compatibility should be weighed. The smart electric mobility operating system proposed in this study can be an important basis for implementing the SDGs' climate change response.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.642-647
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• 2009

We proposed the method of avionics integrated architecture using high-speed fiber optic bus. Typically, data bus of aircraft consists of electronic and optic data transmission method. Avionics systems are difficult to operate the electronic data transmission method for the high speed data processing, synchronization and interconnection between flight control system and flight management system efficiently. In this paper, it is known to look into the problem of data bus and the advanced trend in avionics systems, and propose the appropriate data bus of the advanced avionics systems.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.742-746
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• 2004

전력선 가입자망은 그 잠재적인 활용도가 매우 높아 국내외 전력 회사들의 관심도가 매우 높아지고 있다. 기존의 단순한 전력 공급만을 목적으로 하던 수용가의 전력선을 통신망으로 이용하면 전기 이용은 물론 정보가전기기, 컴퓨터 기기 등의 홈 네트워킹, 홈 오토메이션 및 인터넷 통신이 가능하게 됨으로써 관련 업종의 경쟁력 제고와 전력 사용기기를 최적 제어함으로써 가정의 편리성과 에너지 효율을 극대화 할 수 있다. 또한 전력선망을 보유한 전력회사에서는 원격 수요관리, 검침 및 자동화 기술을 통하여 보다 효율적인 전력 운영과 수용가 이익을 증대화 시킬 수 있다. 본 논문에서는 전력선 통신을 이용하여 원격검침, 수요관리, 고객 관리 및 전력 정보 제공, 심야전력 관리 및 감시 등의 다양한 서비스를 경제적으로 제공하기 위하여 우리나라 실정에 맞는 전력부가 서비스 시스템의 주요 기기들을 설계하고 개발한다.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.3
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• pp.573-578
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• 2019

Recently, the development of indoor positioning technology, base station positioning, Wi - Fi positioning, and Bluetooth beacon positioning technology have been introduced in buildings and underground space. This paper introduces a technique that enables user-oriented ultra-high precision positioning by adopting a lenticular positioning technology, which is a method in which a user directly locates a user's moving line based on a provider-oriented positioning system and service. Through the study on the implementation of coverage using lenticular stickers, we will discuss how to implement coverage of lenticular stickers, which is one of the most important parts of lenticular positioning technology.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.2
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• pp.211-218
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• 2021

Construction sites have various risk factors. There are various approaches to reduce safety accidents, but they have limitations to some extent. By utilizing the wireless communication technology of IT and the rapidly developing image processing technology, it will be possible to reduce accidents at the construction site if risk factors are identified and actively responded to. Therefore, in this study, a system that can detect risk factors of construction sites in advance is constructed, and a system is proposed to discover and respond to risk factors of construction sites using OpenCV for the purpose of real-time computer vision.