• Journal of Power System Engineering
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• v.15 no.5
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• pp.49-53
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• 2011

This study concerns about wireless power generation that uses the energy harvester with EAP actuator. The UWSN(Underwater Wireless Sensor Network) has been considered many times by many researches. Because the information of underwater is getting important to secure the resource or to predict the meteorological phenomena. But the sensor node in the UWSN is driven by the acoustic wave to communicate with other sensor node. And this acoustic wave usually spends a 100 times energy than the RF(Radio Frequency) wave due to transfermation medium(sea water). Therefore the power source of the sensor node is very important that is needed to improve in the UWSN. For this purpose, the energy harvester is made by the acrylic elastomer in this study. And the electrode is modified with an aluminum impurity to improve the efficiency of energy harvester. After that, the modified energy harvester is experimented to confirm the improvement of the energy efficiency.

• Journal of Advanced Navigation Technology
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• v.8 no.2
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• pp.91-97
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• 2004

This paper presents the development of InGaAsP multiple quantum well asymmetric Fabry-Perot modulators(AFPM), which have a vertical structure and high performance and describes measurements of devices operating at 10GHz for next generation broadband wireless communication applications such as picocell systems. Advantages of the AFPM include low drive voltage, which is less than -2V, and -3dB coupling loss, good flatness of the frequency response and simple fiber alignment. A simple link demonstration has been introduced, resulting in 92dB/Hz spurious free dynamic range and 40dB inter-modulation distortion. This modulator could be use for broadband radio over fiber systems such as picocell and multiple RF links.

• Journal of IKEEE
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• v.27 no.4
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• pp.411-417
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• 2023

Unmanned aerial vehicle (UAV)-assisted relay has the advantages of ease of deployment, good communication channels, and mobility over traditional terrestrial relay, which greatly improves wireless connectivity. In this paper, we design a UAV-enabled relay network that can utilize radio frequency bands to harvest energy from sources and utilize terahertz (THz) bands to transmit information between secondary transmitters and receivers. Next, we solve the optimal position of the UAV that maximizes the relay channel capacity, and propose an algorithm to design two trajectories of UAV (a straight and an elliptical trajectory) using the derived solution. Numerical results show that the straight trajectory is better in terms of harvested energy and channel capacity.

• Annual Conference of KIPS
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• 2008.11a
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• pp.1207-1210
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• 2008

무선 센서 네트워크는 고정 인프라 없이 센서 노드만으로 정보를 수집하는 네트워크로서 센서들의 위치정보 식별은 매우 중요하다. 센서 노드간 거리 측정은 신호의 도착시간차(Time of Arrival: ToA), 신호세기(Received Signal Strength: RSS), 신호각도(Angle of Arrival: AoA)에 기반을 둔 방법 등이 있다. 무선 센서 네트워크에 배치되어 있는 각 센서 노드간 정확한 거리 식별을 위해 기존의 거리 측정 방법을 보완하여 거리 오차를 줄이는 ToA기반의 RSS보정 방법을 제안한다. 구체적으로 초음파를 통한 거리측정 값에 맵(RF-MAP)을 통해 보정한 RSS값을 가중치로 보정하여 기존의 거리 측정 방법보다 측정오차를 줄였다. 실험을 통해 제안한 방법은 기존 ToA보다 실내(5m×7m)에서 평균 0.1cm, 실외(10m×10m) 평균 0.6cm 측정 오차를 줄일 수 있음을 확인 할 수 있었다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.9 s.339
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• pp.1-8
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• 2005

A $0.35\mu$m SiGe BiCMOS fabrication process has been timely developed, which is aiming at wireless RF ICs development and fast growing SiGe RF market. With non-selective SiGe epilayer, SiGe HBTs in this process used trapezoidal Ge base profile for the enhanced AC performance via Ge induced bandgap niuoin. The characteristics of hFE 100, $f_{T}\;45GHz,\;F_{max}\;50GHz,\;NF_{min}\;0.8dB$ have been obtained by optimizing not only SiGe base profile but also RTA condition after emitter polysilicon deposition, which enables the SiGe technology competition against the worldwide cutting edge SiGe BiCMOS technology. In addition, the process incorporates the CMOS logic, which is fully compatible with $0.35\mu$m pure logic technology. High Q passive elements are also provided for high precision analog circuit designs, and their quality factors of W(1pF) and inductor(2nH) are 80, 12.5, respectively.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.10
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• pp.45-52
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• 2008

We investigated the design of an RF-powered, wireless temperature sensor tag chip using $0.18-{\mu}m$ CMOS technology. The transponder generates its own power supply from small incident RF signal using Schottky diodes in voltage multiplier. Ambient temperature is measured using a new low-power temperature-to-voltage converter, and an 8-bit single-slope ADC converts the measured voltage to digital data. ASK demodulator and digital control are combined to identify unique transponder (ID) sent by base station for multi-transponder applications. The measurement of the temperature sensor tag chip showed a resolution of $0.64^{\circ}C/LSB$ in the range from $20^{\circ}C$ to $100^{\circ}C$, which is suitable for environmental temperature monitoring. The chip size is $1.1{\times}0.34mm^2$, and operates at clock frequency of 100 kHz while consuming $64{\mu}W$ power. The temperature sensor required a -11 dBm RF input power, supported a conversion rate of 12.5 k-samples/sec, and a maximum error of $0.5^{\circ}C$.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06d
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• pp.25-27
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• 2006

블루투스는 무선 홈 네트워킹을 구성하는 하나의 기술로 자리를 잡았지만, 기존의 홈 네트워킹을 구성하는 IRDA, 무선랜, Home RF, ZigBee 등에 비하여 블루투스 사용으로 인한 큰 이득이 없어 이용되지 않는 것이 현재 블루투스가 직면한 문제이다. 비슷한 통신반경을 지원하는 IRDA와 비교하면 가격과 전력소비에서 블루투스의 이점이 떨어지고, 다중 연결을 지원하는 장점에도 불구하고 10m 내의 전송 반경으로는(저 전력 사용 시) 집안을 전부 커버할 수 없기 때문에 무선랜에 비해 홈 네트워킹에서 이용성이 떨어지는 것이 사실이다. 하지만 이런 블루투스의 AD-HOC 라우팅을(1:1 혹은 1:다) 위한 블루투스 프로토콜 스택에 라우팅 프로토콜 스택을 추가함으로써 블루투스가 장착된 정보 가전기기는 주변으로부터 라우팅 정보를 수집하게 되고 라우팅 테이블을 구성할 수 있게 된다. 그러므로 전송 범위의 이상적인 설계에서 무선랜보다 넓어지게 되므로 홈 네트워킹에서 블루투스 사용의 단점이 보안됨은 물론 집안을 하나의 WEB처럼 구성할 수 있게 된다. 이에 다른 기술에 비한 저렴한 가격, 접속의 용이성, 저 전력 소비 둥과 같은 기존의 장점에 전송 거리의 단점이 보안된 블루투스 라우팅 프로토콜 기술은 IRDA, 무선랜보다 기술적 우위를 가짐으로써 홈 네트워킹에 적용이 많아지리라 예상할 수 있다. 더 나아가 블루투스 기술이 포함되어 있는 모바일 기기가 정점 늘어남에 따라 모바일 기기와의 연동에 의한 홈 네트워킹이 실생활에 적용되리라 예측되며, 집뿐만 아니라 어디에서나 다른 모바일 기기와 연결되어 네트워크를 이루는 유비쿼터스 네트워킹이 실현 될 수 있으리라 본다.-filtered CU)과는 비슷한 결과를 보였다. 결과적으로 제안된 방법은 전통적인 켑스트럴 평균 차감법에 기반하여 효과적인 채널 정규화가 가능하다는 것을 보였다.ttention since the operation of local autonomy in Korea. This trend focuses on ′visual landscape planning′, and it is expected to grow drastically in the near future. Therefore, it is recommended that we promote the more elaborate methodology of ′visual landscape planning′, which also includes the ecological and cultural aspects of the environment. 7월 시료에는 ethane, ethyl formate, trans-2-hexenal의 순서로 그 함량이 많았으며, hydrocarbon류가 전체성분의 30.42%를 차지하였다. 8월 시료는 benzyl alcohol, ethyl formate 및 trans-2-hexenal의 순서로 많이 함유되어 있었으며, ester류가 35.60%를 차지하였다. 또한 9월 시료에도 ester류가 32.92%를 차지하였으며 ethyl acetate, benzyl alcohol, ethane 및 trans-2-hexenal의 순서로 함량이 높았다.to isolate the major component of silkworm powder, which exerts blood glucose-lowering e

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.6
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• pp.923-931
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• 2013

RFID (Radio Frequency Identification), which is a kind of the electronic tag, is a wireless access device using the radio frequency for recognizing the ID information. It has a variety of application such as the bus card, gate access card, distribution industry, and management of construction materials. The performance and size of RFID depend on the penetrability, recognition ratio, memory size, multi tag recognition, external pollution dust, and exterior impact, and RFID requires the packaging to protect itself considered above factors. Recently, RFID is diversely employed to effectively manage construction materials and the RFID packaging, which is robust to the external impact, is required to attach RFID on construction materials. In this paper, we propose the construction material RFID packaging designed to be robust for the external impact and to be practicable for change of the broken RFID. For the change of RFID, we separate the cast and body of the packaging. Also, we present the detail drawing for the proposed construction material RFID packaging and implement the performance evaluation of the packaging manufactured using 3D printer.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.4
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• pp.629-635
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• 2009

The FSK duplex remote controlling wireless transmission units with a common local oscillator circuit for transmitter and receiver are designed and implemented in this paper. In the FSK full-duplex the channel frequency for Tx/Rx is allocated, a common switching oscillator circuit for Tx/Rx is designed in the FSK half-duplex scheme. Both of FSK units get functions of automatic channel detection for busy channels and channel configuration for an idle channel in order to reduce the RF channel interference and are designed as a remote controller with small-sized low power of 10mW and the 400MHz-colpitz type PLL configuration of 50kHz channel separation. The full-duplex Tx/Rx link frequency gets frequency difference of 42.8MHz, which is double of 21.4MHz IF frequency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.10A
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• pp.965-973
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• 2007

We analyzed that the loss of data in TCP protocol based wireless networks caused by overlapped responses in bi-directional nodes that were resulted in out of the data sequence. This loss can be prevented by using revised TCP rate control algorithm and the performance of throughput can also be improved. The rate control algorithm is applied when the congestion happens between nodes while traffic packets are retransmitting in TCP bandwidth. In addition to applying the rate control algorithm, we determine the number of system clients in bandwidth and the average of pausing time between transmitting serial files to produce a competitive level so that an efficient performance of rapid retransmitting for the loss of multi-packets. This paper discusses the improvement of congestion control in that the decrease of the loss, firstly, as ensuring an efficient connection rate and, secondly, as using sliding window flow control.