• Journal of Information Display
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• 제5권4호
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• pp.38-44
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• 2004

In this paper, a server and client simulator for the web-based multi-view 3D image communication system is implemented by using the IEEE 1394 digital cameras, Intel Xeon server computer and Microsoft's DirectShow programming library. In the proposed system, two-view image is initially captured by using the IEEE 1394 stereo camera and then, this data is compressed through extraction of its disparity information in the Intel Xeon server computer and transmitted to the client system, in which multi-view images are generated through the intermediate views reconstruction method and finally display on the 3D display monitor. Through some experiments it is found that the proposed system can display 8-view image having a grey level of 8 bits with a frame rate of 15 fps.

• 한국정보처리학회논문지
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• 제7권3호
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• pp.901-908
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• 2000

Satellite communication in the 21 century's high tech information world is developing rapidly, marked by high levels of applications and functions. For example, satellite communication can process and switch the speed of the service provided by a broad and vast digital multimedia system such as a long-distance all between nations or broadcasting transfer service, which is supplied by a contemporary satellite system. So, it bring about problems which lack of satellite orbit and gibes out frequency resource by increment of satellite universally. To support this, an OBP satellite system is need, which includes an on-board IF/RF switch, baseband signal processing, multi-beam antenna technology, as well as a simple transponder system. In this paper, we have outlined the next generation of satellite communication; satellite OBP transport network architecture, which offers multimedia service and applied frequency reuse method for multi-spot beam. The satellite B-ISDN transport network architecture is also analyzed.

• 디지털산업정보학회논문지
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• 제16권1호
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• pp.99-109
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• 2020

In the past, conservative concepts have been applied in terms of the characteristic of nuclear power plants(NPPs), resulting in analog-based equipment and closed networks. However, as digital technology has recently been applied to the design, digital-based facilities and communication networks have been used in nuclear power plants, increasing the risk of cybersecurity than using analog-based facilities. Nuclear power plant facilities are divided into a safety system and a non-safety system. It is essential to identify the difference and cope with cybersecurity threats to the safety system according to its characteristics. In this paper, we examine the cybersecurity regulatory guidelines for safety systems in nuclear power plant facilities. Also, we analyze cybersecurity threats to a programmable logic controller of the safety system and suggest cybersecurity requirements be applied to it to respond to the threats. By implementing security functions suitable for the programmable logic controller according to the suggested cybersecurity requirements, regulatory guidelines can be satisfied, and security functions can be extended according to other system requirements. Also, it can effectively cope with cybersecurity attacks that may occur during the operation of nuclear power plants.

• 디지털산업정보학회논문지
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• 제5권1호
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• pp.33-41
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• 2009

Network industry is complex combined with various fields of industry, such as communication, broadcast, construction, and home appliances. Moreover, it's fairly lucrative since the growth industry makes lots of added values, interacting with the others.The network industry, usually called 'Ubiquitous', connects some home appliances and makes an integrated system that you can use them with whenever and wherever. A demand for network security, however, has skyrocketed due to the relatively low safety. It's been expected that the market of home security is going to be grown up nearly 30 percent every year. Recently, analog surveilance cameras have been replaced with digital ones, and they will be providing stronger security services taking advantage of mutual interaction with related industies. In this paper, a mobile monitoring system for home security is proposed, which makes it possible to supervise all home appliances wherever you're, using the conventional wired/wireless network infra.

• ETRI Journal
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• 제39권3호
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• pp.364-372
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• 2017

For the reliability of controllers in a software defined network (SDN), a dynamic and self-learning schedule method (DSL) is proposed. This method is original and easy to deploy, and optimizes the combination of multiple controllers. First, we summarize multiple controllers' combinations and schedule problems in an SDN and analyze its reliability. Then, we introduce the architecture of the schedule method and evaluate multi-controller reliability, the DSL method, and its optimized solution. By continually and statistically learning the information about controller reliability, this method treats it as a metric to schedule controllers. Finally, we compare and test the method using a given testing scenario based on an SDN network simulator. The experiment results show that the DSL method can significantly improve the total reliability of an SDN compared with a random schedule, and the proposed optimization algorithm has higher efficiency than an exhaustive search.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1713-1716
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• 2002

In this paper, we analyzed the performance of SDR-based dual-band CDMA system in wideband multipath channel employing RAKE receiver with MRC diversity. For the simulation of SDR-based dual-band CDMA system, we used digital If techniques, polyphase analysis filter bank as channelizer, where Remez exchange algorithm is employed in the realization of the digital filter.

• 전력전자학회논문지
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• 제21권1호
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• pp.49-57
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• 2016

A modular multilevel converter is widely adapted for a high-voltage direct current power transmission system. This study proposes a design methodology for a novel digital control that mitigates the negative effects caused by time delay, including communication transport delay for a modular multilevel converter. The modeling and negative effect of time delay are analyzed theoretically in a frequency domain, and its compensation methodology based on an inverse model is described fully with practical considerations. The proposed methodology is verified through several simulation results using a modular 21-level converter system.

• 한국통신학회논문지
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• 제41권3호
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• pp.331-337
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• 2016

본 논문은 자기간섭 (self-interference, SI) 신호가 존재하는 환경에서 동일대역 전이중 방식 통신 시스템의 성능과 SI 제거 기법에 대해서 분석하였다. 동일대역 전이중 방식 통신 시스템이 원하는 오율 성능을 달성하기 위해서는 SI 신호를 제거해야 하며, 이는 전파 영역과 아날로그 영역, 디지털 영역에서 차례로 수행되어야 한다. 전파 영역에서 안테나의 송수신 빔을 물리적으로 분리시켜서 신호 감쇄를 달성할 수 있다. 아날로그 영역과 디지털 영역에서는 SI 신호의 채널 추정값과 송신 신호를 기반으로 SI 신호를 재생한 후에 원하는 수신 신호로부터 제거할 수 있다. 본 논문에서는 전파 영역에서의 SI 신호를 충분히 감쇄시킬 수 있다고 가정하고, Least squares 방식으로 SI 신호의 채널을 추정하고 그 추정값을 기반으로 아날로그 영역과 디지털 영역에서 SI 신호를 순차적으로 제거하여 동일대역 전이중 방식 통신 시스템이 원하는 오율 성능을 달성할 수 있음을 확인하였다.

• 한국정보통신학회논문지
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• 제24권4호
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• pp.508-514
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• 2020

LTE (Long Term Evolution) 및 5G와 같이 지속적으로 발전하는 이동 통신 표준을 구현하기 위해 소프트웨어 정의 라디오 (SDR, Software Defined Radio) 개념은 뛰어난 유연성과 효율성을 제공한다. 수년 동안, 최고급 디지털 시그널 프로세서 (DSP, Digital Signal Processor) 시스템 온 칩 (SoC, System on Chip)은 멀티 코어 및 다양한 하드웨어 보조 프로세서를 지원하는 방향으로 개발되어왔다. 이 논문에서는 TI의 TCI663x 칩을 사용해 구현한 SDR 플랫폼 하드웨어에 대해 소개하고, 이 플랫폼 상에서 멀티 코어 DSP를 BCP (Bit Rate Coprocessor) 및 TPC (Turbo Decoder Coprocessor)와 연동하여 구현한 LTE 전송 채널 (Transport Channel)의 성능을 다양한 구현 옵션에 따라 평가한다.

• 한국정보통신학회논문지
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• 제26권7호
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• pp.1004-1012
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• 2022

본 논문은 디지털 게임 기반의 학습 방법을 이용해 패키지 투어에 참여하는 여행자들에게 관광지 정보를 게임 형식으로 학습하도록 하는 서비스 개발 내용을 담고 있다. 이 게임은 안드로이드 기반의 스마트폰을 대상으로 하여 자바(Java) 언어로 구현했으며, 콘텐츠 관리 시스템(CMS)을 통해 게임 콘텐츠, 여행자 정보, 게임 결과 등을 체계적으로 관리할 수 있도록 하였다. 한 개의 관광지 소개 레벨과 다섯 개의 퀴즈 게임 레벨로 구성된 이 게임은 각 레벨 별로 점수 보상과 시간 벌칙을 제공하고 있어 게임의 흥미를 더해주며, 게임 종료시에는 이를 종합적으로 고려해 획득 점수를 계산한 후 리더 보드에 등재시켜 준다. 성능 평가 결과 데이터베이스와 게임 간에 0.9초의 응답 시간을 보여주고 있어 만족할 만한 결과임을 알 수 있었다. 본 논문에서 구현한 게임은 여행자 관리를 위한 패키지 투어 애플리케이션 내에 탑재되어 운영됨으로써 여행자들로 하여금 패키지 투어에 대한 만족도를 높여주는 계기가 될 것이라 기대한다.