• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.557-560
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• 2004

In this paper, wireless internet services are combined with conventional wire internet service system. These system support that instrument manager can be access his instrument by use personal mobile devices and instrument manager can be take emergency action by use mobile devices. for this, error signal of local instruments are transmitted to the serial port of local server through Rf wireless communication channel. Also, The image of local instruments are transmitted to the web monitoring screen of main server. Network Camera System Supports remote monitoring functions. The interfacing of nam server with external user are possible through the mobile devices.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.2
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• pp.1-9
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• 2012

Reinforced concrete buildings will be deteriorated as passed time or effect of an earthquake, etc in main elements. In order to manage such cracks, time and efforts, expense, etc, are required. So micro lead switch sensors are embedding or bonding in flexible specimens, and these are smart elements for diagnostic crack damages by external force such as physical load, dynamic load, etc in this study. The monitoring to crack damages are studied using radio frequency system. If load is received on the center of flexible specimens, embedded and bonded lead switch sensors will be destroyed, and these become to send signals of damages at radio frequency system connected with lead switch sensors. This study is fundamental research of the diagnostic system for architectural elements using radio frequency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.2
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• pp.385-390
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• 2008

The Study of environment monitoring through huge network of wireless sensor node is worked with activity. The sensor nodes must be very small, light and low cost. The localization which may determine where a given node is physically located in a network is one of the quite important problems for wireless sensor network. But simple localization method is required as excluding the usage of GPS(Global Positioning System) by the limit condition such as the node size, costs, and so on. In this paper, very simple method using connectivity for the outdoor RF communication environment is proposed. The proposed method is demonstrated through simulation.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.5
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• pp.755-760
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• 2023

In this paper, the 2.4/5GHz dual band was used to ensure the reliability and stability of the wireless AV surveillance system using the existing 2.4GHz band. The proposed system supports dynamic channel allocation and channel change technology to avoid interference from other signals (Wifi, Bluetooth, etc.), reduces maintenance costs incurred when building wireless CCTV, and can be linked with existing wired CCTV. The service area of the A/V surveillance system used can be expanded.

• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.411-414
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• 2004

This paper introduces a modulation method for digital wireless communication based on general DS-QPSK. The design and fabrication is for home networking application to a typical RF transmitter with DS-QPSK modulator. This modulator implemented using VHDL hardware programming language, the fabrication of IC chip $5{\times}5 mm^2$ was carried by 27th IDEC MPW(Multi Project Wafer) process in 0.35${\mu}m$ rule at Samsung Inc. This paper presented the important of this technology for the future application in wireless sensor. This module can be efficient usage for home network to transmit the RF wireless sensor system.

• Information and Communications Magazine
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• v.32 no.4
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• pp.93-96
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• 2015

기존 MIMO 시스템에서는 안테나의 개수가 늘어날수록 선형적으로 RF 모듈의 개수도 늘어나 전체 시스템의 복잡도와 전력소모가 심하다. 이를 해결하기 위해 단일 RF 송신구조가 제안되었고, 본 논문에서는 임피던스를 가변하여 안테나에서 방사되는 패턴을 조절하는 기술을 제안한다. 기존 MIMO 시스템의 RF 회로부가 가지는 복잡도와 전력 효율 문제를 해결하기 위해 임피던스 로딩 부분의 실험시제품 제작 및 검증을 수행한다. BPSK와 QPSK 변조방식을 지원하는 임피던스 로딩 보드를 제작하고, 3 m거리에서 무선 송수신 실험을 성공적으로 수행하였다.

• Information and Communications Magazine
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• v.32 no.6
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• pp.59-61
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• 2015

기존 MIMO 시스템에서는 안테나의 개수가 늘어날수록 선형적으로 RF 모듈의 개수도 늘어나 전체 시스템의 복잡도와 전력 소모가 심하다. 이를 해결하기 위해 단일 RF 송신구조가 제안되었고, 본 논문에서는 임피던스를 가변하여 안테나에서 방사되는 패턴을 조절하는 기술을 제안한다. 기존 MIMO 시스템의 RF 회로부가 가지는 복잡도와 전력 효율 문제를 해결하기 위해 임피던스 로딩 부분의 실험시제품 제작 및 검증을 수행한다. BPSK와 QPSK 변조방식을 지원하는 임피던스 로딩 보드를 제작하고, 3 m거리에서 무선 송수신 실험을 성공적으로 수행하였다.

• Journal of the Semiconductor & Display Technology
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• v.15 no.4
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• pp.16-21
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• 2016

In this paper, we have designed and fabricated a receiver module for 5.8GHz Microwave Wireless Power Transmission. The receiver module was composed of an antenna, BPF (Band Pass Filter) and RF-DC converter. The antenna was designed to RHCP (Right Hand Circular Polarization). And we used ${\lambda}g/2$ open-circuited stubs for the BPF. In addition, the RF-DC converter used the tripler voltage circuit for voltage multipliers. The integrated receiver RF module for 5.8GHz Microwave Wireless Power Transmission has been designed and fabricated. The voltage was measured to the distance of 50cm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.5
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• pp.928-938
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• 1994

We designed and implemented (3.3) tap Decision Feedback Equalizer using Zero Forcing algorithm for 64 QAM RF MODEM (155Mbps) in SDH STM-1, Before we designed DFE, simulate 11 tap linear equalizer and (3.3) tap DFE. Then we get results that performance of DFE is better than linear equalizer by 5dB in fading. Practically, implemented DFE have good performance equalizing signal in 20dB fading depth.

• Journal of the Semiconductor & Display Technology
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• v.14 no.4
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• pp.88-91
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• 2015

In this paper, we have designed and fabricated a BPF (Band Pass Filter) for 5.8GHz Microwave Wireless Power Transmission. We $used{\lambda}g/2$ open-circuited stubs in addition to T-shaped transmission lines for the BPF. This BPF removes harmonics caused by diodes of RF-DC converter, and thus the RF-DC converter converts more RF power to the DC. The performance of the BPF was measured and shown through direct comparison of voltages converted by the doubler as a RF-DC Converter with and without the BPF.