• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.7 s.337
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• pp.1-6
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• 2005

Now that the reduction of the cell size in order to serve the increasing subscribers has raised the frequency of the location update, it has increased the cost of location management. In this paper, we show that the location management strategy based on the call arrival probability(CAP) can reduce the cost of the location management by analyzing that cost in this strategy which was proposed in [1] to reduce the cost of the location management in mobile communication. And we compare the location management cost by analyzing with that by simulating.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.6
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• pp.609-614
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• 2009

The TT&C communication subsystem of STSAT-3 is consisted of communication link to send telemetry data of spacecraft to the ground station and receive command data from ground station. The S-band receiver is used to receive command data from ground station, Engineering Qualification Model of S-band receiver has been designed and manufactured. The Designed S-band Receiver uses a single conversion for a simple frequency conversion, including a DC-DC Converter and EMI Filter. Also, Digital demodulation part designed using FPGA and RS-422 data interface. The performance of S-band Receiver in functional and space environments test satisfies the requirements of STSAT-3.

• Journal of Korea Society of Industrial Information Systems
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• v.15 no.2
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• pp.17-22
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• 2010

Establishment of systematic platform is needed for technological progress of receiving of satellite image data with high quality and processing system for product generation and operation related with direct receiving system for satellite from abroad. Besides, it's necessary to develop the integrated data processing system to prohibit similar functions on developing (or being developed) for KOMPSAT-3, KOMPSAT-5 and to operate system efficiently. Therefore, conceptual design of the integrated data processing system is performed considering commercialization of KOMPSAT(Korea Multi-Purpose Satellite) series based on KOMPSAT-2 IRPE on operation in this paper.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4A
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• pp.566-572
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• 2000

In the receiver of optical communication systems, a demultiplexer converts to a single data stream with a highbit rate into several parallel data streams with a low bit rate. In this paper, we design a 1:4 demultiplexer using SiGe HBT with emitter size of 2x8um² The operation speed is 10Gbps, the rise and fall times of 20-80% are37ps and 36ps, respectively and the dissipation of power is 1.40W.

• Journal of the Korea Society of Computer and Information
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• v.10 no.2 s.34
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• pp.169-177
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• 2005

The Conditional Access System is a complete system for ensuring that broadcasting services be accessible to only those who are entitled to receive them. Secure key management and efficient delivery mechanism are very important design factors to this system. In this paper, we propose secure and efficient protocols which would be well fitted to a Pay TV system including the satellite DMB. Further. by applying our protocol to the existing conditional access system, we propose a new system that properly enables the control of conditional access to the Pay TV in satellite DMB environment.

• Childhood Kidney Diseases
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• v.9 no.1
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• pp.69-75
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• 2005

Purpose : The most important management of congenital hydronephrosis consists of the early diagnosis and evaluation of the pathologic abnormalities of congenital hydronephrosis. This study was conducted to investigate the different causes of hydronephrosis and its clinical outcome. Methods : 54 live neonates who were hospitalized and diagnosed with congenital hydronephrosis at Chungnam National University Hospital from Aug. 1998 to Aug. 2003 were retrospectively analyzed. Results : Hydronephrosis(renal pelvic AP diameter $gt;5 mm) was postnatally detected in 54 cases(2.1%) among 2,539 neonates who were hospitalized from Aug. 1998 to Aug. 2003. There were three times more males than females. Additional imaging studies revealed that ureteropelvic junction obstruction was the most common postnatal diagnosis(48.7%), followed by multicystic dysplastic kidney, vesicoureteral reflux and duplication kidney with ureterocele. Spontaneous regression of hydronephrosis was revealed in 25 renal units(75.8% ) of mild hydronephrosis, 14 renal units of moderate hydronephrosis and 1 renal unit of severe hydronephrosis. Operative correction were carried out in 14 renal units(70%) of severe hydronephrosls. Conclusion : The most common established cause of congenital hydronephrosis in this study was ureteropelvic junction obstruction. There are many cases of spontaneous regression in mild to moderate congenital hydronephrosis. Urinary tract infections occur in many neonates with hydronephrosis. Therefore, early detection and evaluation of congenital hydronephrosis and continuous follow-up at regular intervals are necessary for conservation of renal function. (J Korean Soc Pediatr Nephrol 2005;9:69-75)

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.104-105
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• 2008

요즘 데이터의 양이 많아지고 마이크로프로세서의 속도가 빨라짐에 따라 광통신이 각광받고 있다. 광통신이란 전류신호를 광 신호로 변환하여 송신하고 광섬유를 통해 전달된 광신호가 포토다이오드를 통해 전류신호로 변환되어 수신하는 통신방법이다. TIA는 이런 광통신의 수신부의 첫 단에 오는 블록으로서 전류신호를 사용가능한 전압신호로 바꾸어주는 역할을 한다. 본 논문에서는 포토다이오드의 커패시턴스 성분을 효과적으로 차단하고 노이즈 특성을 향상시킬 수 있는 방법을 제안하고, 1.8V 0.18um CMOS공정을 사용하여 2.5Gbps TIA 블록을 설계하였다.

• Electronics and Telecommunications Trends
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• v.24 no.1
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• pp.12-23
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• 2009

광트랜시버는 광전송 시스템, 대용량 라우터 및 스위치 등의 광통신 장치에서 전기 신호를 광신호로 바꿔 광섬유를 매체로 송신하며 송신된 광신호를 수신하여 다시 전기 신호로 바꿔주는 광송신과 광수신 기능을 담당하는 모듈을 말한다. 광 송수신 모듈은 초창기 155M, 622M, 2.5 Gb/s SDH/SONET 시스템에 사용되었을 때에는 광송신기와 광수신기가 분리되어 있는 구조였으나, 2000년 이후에 들어서서 광송신기와 수신기가 하나의 패키지 안에 구현된 지금의 광트랜시버 모듈이 등장하였다. 또한, 광트랜시버 모듈 업체를 중심으로 시스템 업체, 부품업체들이 모여 산업체 표준(MSA)을 정하면서 개발 비용과 시간 단축의 효과를 거두는 동시에, 기술면에서도 비약적인 발전을 거듭하고 있다. 이러한 광트랜시버의 발전 방향은 고속화, 소형화, 고성능화, 저가격화로 요약할 수 있다. 본 고에서는 10 Gb/s, 40 Gb/s, 100 Gb/s 광트랜시버를 중심으로 기술동향을 설명하고, 광트랜시버를 개발하는 데 필요한 요소기술에 관하여 살펴본다.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1995.10a
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• pp.834-838
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• 1995

• ETRI Journal
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• v.9 no.2
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• pp.92-95
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• 1987

코우히어런트 광전송에 관한 연구의 현황을 간략히 기술하였다. 그 내용은 광원인 단일 주파수 레이저의 안정화 방법, 광의 변조 방식, 국부 발진광의 주파수 변환 방법, 평형 광검파 방법, 수신 광신호와 국부 발진광의 편극 상태를 정합시키는 기법 및 파장 분할 다중화 기술등이다.