• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.137-140
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• 2001

In this paper, we propose a multicast routing scheme for an efficient and reliable support of multicast service to mobile hosts in IPv6 based networks. The purpose of this paper is to develop an algorithm to reduce both the number of multicast tree reconstruction and the multicast service disrupt time using the RSVP scheme. The proposed multicast routing scheme is a hybrid method using the advantages of the hi-directional tunneling and the remote subscription proposed by the IETF Mobile IP working group. The proposed scheme satisfies the maximum tolerable transfer delay time and supports the maximum tunneling service. The simulation results show that the proposed scheme has better performance in the number of multicast tree reconstruction and the time of multicast service disrupt than the previous schemes does.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2224-2227
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• 2003

본 논문에서는 비동기식 3 세대 이동통신망인 WCDMA의 표준 음성 부호화기인 AMR(Adaptive Multi-Rate)[1]과 VoIP(Voice over Internet Protocol) 응용분야에 최근 널리 활용되고 있는 ITU-T 8kbit/s 0.729A[2]의 효율적인 연동을 위한 상호부호화(transcoding) 알고리듬을 제안한다. AMR은 통신 채널 환경에 따라 4.75kbit/s부터 12.2kbit/s까지 가변 하여 통화품질을 보장한다. 따라서, 제안된 상호부호화 알고리듬은 순방향 8 모드, 역방향 8모드를 합하여 총 16모드를 지원한다. 제안된 알고리듬의 성능 평가를 위해 지연 추정, 연산량 측정과 주/객관적 음질평가를 수행한 결과, 제안한 알고리듬은 기존의 tandem보다 최소 5㎳의 짧은 지연, 평균 50.2％의 적은 연산량으로 우수한 음질의 복호화 음성 신호를 제공함을 확인하였다.

• Annual Conference of KIPS
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• 2001.04b
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• pp.1189-1192
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• 2001

향후 인터넷은 이동 환경하에서 메일, 파일 전송 등의 비실시간 응용 뿐만 아니라 음성, 비디오, 인터넷 방송 등의 실시간 응용 서비스를 이용하려는 욕구가 증가할 것으로 예상되며, 이를 위해 광대역 서비스 뿐만 아니라 사용자별 차별화된 QoS의 보장이 요구된다. 본 논문에서는 전송속도 및 대역폭 할당의 개선을 위해 WDM 전송망을 백본망으로 하는 이동 인터넷망에서의 QoS 제공 방안을 제시한다. 우선 WDM 전송망을 기반으로 하는 이동 인터넷망의 모델을 제시하고, 트래픽의 특성 및 QoS 파라메타를 분석한 다음, QoS 제공 방안을 제안하고, QoS제어를 위한 프로토콜 구조 및 각 계층별 기능을 설명한다.

• Annual Conference of KIPS
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• 2003.11b
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• pp.1045-1048
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• 2003

최근 인터넷 환경이 널리 퍼지면서 인터넷 서버들의 보안위협은 갈수록 증가하고 있다. 이러한 인터넷 서버의 보안 사고를 예방하기 위하여 기관들은 정보보호 솔루션인 방화벽, 침입탐지 시스템, 바이러스 백신, 보안운영체제 등을 도입하였으나 개별적인 보안 솔루션을 적용함으로써 관리 효율성이 떨어지고 보안 사고 위험은 증가하고 있다. 그래서 현재는 개별 보안 솔루션을 통합관리하는 ESM 을 도입하고 있다. 차세대인터넷 서버도 인터넷에 연결되어 있어서 해킹으로부터 자유로울 수 없기 때문에 차세대 인터넷 서버에 적합한 ESM 이 필요하다. 우리는 공개 소프트웨어 보안 도구를 조합하여 응용 프로세스 레벨에서 가볍고 기본 보안 기능을 충실히 갖춘 ESM 을 설계하였다. 본 논문에서는 그 ESM 의 설계 내용을 중심으로 자세히 소개하고, 현재까지 구현된 결과도 간략히 소개한다.

• Journal of Korea Society of Industrial Information Systems
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• v.11 no.5
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• pp.78-85
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• 2006

Thanks to the spacial and timely flexibility of laboratory's environment, the distance learning based real time PLC education system has been brought into relief as a next generation laboratory alternative. The developed system was installed using a relatively cheap PLC and PC camera. Providing image feedback through the PC camera, the system provides the student's interests of the lab as well as an opportunity to monitor the lab's activities and results.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.368-376
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• 2007

The large potential bandwidth available in wavelength-division multiplexed optical networks makes this technology of crucial importance for satisfying the ever increasing capacity requirements of the next-generation Internet. In this scenario, the routing and wavelength assignment(RWA) problem that concerns determining the optical paths and wavelengths to be used for connection establishment in a wavelength-routed network, is still one of the most important open issues. In this paper we propose a new online dynamic grooming-capable RWA heuristic scheme working on wavelength division multiplexing(WDM) networks as a multistage selection process. The proposed algorithm is transparent with respect to the presence of wavelength converters, achieves very low connection rejection ratios with minimal computational complexity and is appropriate for the modern multilayer optical circuit and wavelength switched networks with sparse wavelength conversion capability.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1201-1208
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• 2008

Ubiquotuous technology should be adopted in railroad business to provide passenger's security and convenience. In this project, IT and smart sensor technologies are reviewed, benchmarked, designed, and implemented. The target system is the next generation high speed train to be developed and operated in Korea with the maximum speed of 400km/h. Wireless sensor network with smart sensors is implemented around a train car. PC-like IT terminal will be designed and implemented so an individual passenger can use it to do information retrieval through the Internet, personal data processing, the e-learning, shopping on the railroad, and so on. These provision will give comfort, convenience, and safety of a passenger during his/her trip.

• Journal of Digital Convergence
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• v.9 no.1
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• pp.61-70
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• 2011

Ultimately, this research will focus on the activity traits of future customers in the convergence age. To accomplish that, firstly, researcher develop measures for assessing the convergence level of digital devices and digital services. Next, this will investigate the behavioral traits of people who use specific devices or services on the internet or mobile networks. This study proposed five convergence measures each for devices and services. For digital devices, measures such as converged functions, accessibility to network, portability, immediate communicability, and expandibility of functions were utilized. For digital measures such as scope of users, newness, social network level, ease-of use on mobile networks, and expandibility of information were used. We believe that the research results can provide insights for those wishing to explore the convergence level of devices and services and those developing high-level converged devices and digital services.

• Electronics and Telecommunications Trends
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• v.33 no.5
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• pp.86-94
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• 2018

Information-Centric Networking (ICN) has been recognized as a new networking technology for the upcoming data-centric 4th industrial revolution based society. In addition, it has noted that Pub/Sub-style communication is rapidly growing in areas including big data processing and microservice as well as the existing Internet of Things and social networking technologies. Therefore, ICN is highly needed to efficiently support Pub/Sub-style communication for successful deployment as a next-generation network infrastructure technology. This paper summarizes the recent research trends of Pub/Sub communication technologies over ICN, and discusses future research issues.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.184-184
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• 2008

In this paper, a power divider with a multi-band and broadband are designed and fabricated using an InGaP/GaAs process. The design of this divider is based on multi-band because it is important in the next generation IMT-Advances system. In this design, power divider is fabricated with the frequency of 824 MHz to 894 MHz, 1.8 GHz to 2.2 GHz and 2.3 GHz to 2.4 GH for cellular, personal communication system (PCS) and Wireless Broadband Internet (WiBro). The topology of the designed power divider is based on the multi-section and fabricated using integrated passive device (IPD) library of nanoENS Inc. It is measured using network analyzer.