• 한국통신학회논문지
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• 제33권11B호
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• pp.989-997
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• 2008

The reverse acknowledgment (RA) scheme supports a fast loss recovery for negative acknowledgment (NAK)-based selective repeat automatic repeat request (SR-ARQ) by detecting a retransmission failure quickly before a retransmission timer expires. In this paper, we evaluate the performance of a NAK-based SR-ARQ protocol with the RA scheme and compare it with the conventional NAK-based SR-ARQ protocol. Particularly, we propose a simple analysis model for the transport delay of the NAK-based SR-ARQ protocol considering the traffic condition, the retransmission persistence, the timer-based retransmissions and the RA scheme's behavior. Both NAK-based SR-ARQ protocols with and without the RA scheme are implemented by using the OPNET simulator. We verified the analysis model's accuracy through the simulation results. Also, we evaluate the performance of the NAK-based SR-ARQ protocol with the RA scheme based on analysis and simulation results.

• 한국통신학회논문지
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• 제24권7A호
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• pp.955-963
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• 1999

본 논문에서는 위성 통신망에서의 효율적인 키 분배 프로토콜에 대한 성능을 분석하기 위하여 지상망에서 적용되는 키 분배 프로토콜중에서 Kerberos와 같은 push 모델과 X9.17로 대표되는 pull 모델에 대한 키 분배 처리 전차를 분석하고 분석된 키 분배 프로토콜이 위성망을 통하여 수행되는 절차를 기술하였다. 아울러, VSAT 위성 통신에서 키 분배 프로토콜이 Inband/Outband 채널을 통하여 처리되는 경우에 키 분배 프로토콜의 성능을 처리 지연과 처리율 측면에서 분석하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.53-54
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• 2006

In this paper, we analytically evaluate packet delay and energy consumption of S-MAC protocol with a modified Markov chain model. Although some models, based on IEEE 802.11 MAC protocol, to analyze the S-MAC protocol in wireless sensor network (WSN) have been proposed, they fail to consider the differences in architecture between the S-MAC and the 802.11 MAC. Therefore, by reflecting the significant features in the S-MAC function, we model the operation of S-MAC protocol, and derive its packet delay and energy consumption in single-hop WSN. Numerical results show the delay and the dissipated energy at various duty cycle values according to offered load, where a practical mote is used.

• 한국통신학회논문지
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• 제15권2호
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• pp.98-111
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• 1990

본 논문에서는 CCITT에서 권고한 ISDN D-채널 access protocol의 queueing 모델을 제시하였으며 그 모델을 이용하여 signalling message와 packet message의 delay의 Laplace transform을 구하였다. 그 분석결과는 simulation을 통하여 검증하였으며, 또한 D-채널 access 시스템에서의 packet 및 signalling message 의 delay 특성에 대하여 비교 설명하였다.

• 한국통신학회논문지
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• 제36권7A호
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• pp.662-668
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• 2011

본 논문에서는 MANET (Mobile Ad hoc Network)를 위한 가장 대표적인 라우팅 프로토콜인 AODV (Ad hoc On-demand Distance Vector)와 OLSR (Optimized Link State Routing)의 성능을 노드 이동성 모델에 따라 분석한다. 노드의 이동성은 망 토폴로지의 변화를 일으키므로 라우팅 프로토콜의 성능에 많은 영향을 미친다. 따라서, MANET 라우팅 프로토콜의 성능을 정확하게 평가하기 위해서는 노드의 이동 패턴에 가장 적합한 이동성 모델을 사용하는 것이 무엇보다 중요하다. 본 논문에서는 기존 MANET 라우팅 프로토콜 성능분석에 가장 많이 사용되고 있는 random way point 모델과 최근에 실제 인간의 이동 패턴과 가창 유사하다고 발표된 Levy walk 모델을 기반으로 AODV와 OLSR의 성능을 ns-2 시뮬레이션을 통해 비교 분석한다.

• 한국철도학회논문집
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• 제7권2호
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• pp.114-119
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• 2004

According to the computerization of railway signalling systems. the communication protocol for interface between these systems are required. Therefore the new communication protocol for railway signaling system is required. Generally, there are two verification method for new designed protocol in the industrial and academic fields. One is the laboratory testing method which is very popular and general technique. In our research the comparison between existing and new designed protocol for signaling is described and the verification test results are also represented. From these laboratory test, we are verified the conformance of new designed protocol. Another method is verified by formal method. The format verification method is widely used at safety-critical system design but this approach is nor popular at verification communication protocol. However it is very important to verify the safety of new designed protocol for railway signaling system because signaling systems are very safety-critical systems. So, the methodology for formal verification of designed protocol is also reviews in this paper.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.462-467
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• 2003

According to the computerization of railway signalling system, necessity of communication protocol for interface between these equipments is increasing. Therefore the research on communication protocol structure that is required according to computerization trend of these signalling goes. In our research the existed protocol currently used was analyzed, and the simulation modeling for performance analysis is deduced. Based on this simulation model the performance analysis and comparison is carried out, and also validation test is executed about new suggested protocol.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1318-1320
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• 2003

According to the computerization of railway signalling system, necessity of communication protocol for interface between these equipments is increasing. Therefore the research on communication protocol structure that is required according to computerization trend of these signalling goes. In our research the existed protocol currently used was analyzed, and the simulation modeling for performance analysis is deduced. Based on this simulation model the performance analysis and comparison is carried out, and also validation test is executed about new designed protocol.

• Journal of Communications and Networks
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• 제12권6호
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• pp.592-599
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• 2010

In recent years, significant improvements have been made to the techniques used for analyzing satellite communication and attacking satellite systems. In 2003, a research team at Los Alamos National Laboratory, USA, demonstrated the ease with which civilian global positioning system (GPS) spoofing attacks can be implemented. They fed fake signals to the GPS receiver so that it operates as though it were located at a position different from its actual location. Moreover, Galileo in-orbit validation element A and Compass-M1 civilian codes in all available frequency bands were decoded in 2007 and 2009. These events indicate that cryptography should be used in addition to the coding technique for secure and authenticated satellite communication. In this study, we address this issue by using an authenticated key-exchange protocol to build a secure and authenticated communication channel for satellite communication. Our protocol uses identity-based cryptography. We also prove the security of our protocol in the extended Canetti-Krawczyk model, which is the strongest security model for authenticated key-exchange protocols, under the random oracle assumption and computational Diffie-Hellman assumption. In addition, our protocol helps achieve high efficiency in both communication and computation and thus improve security in satellite communication.

• 정보처리학회논문지C
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• 제10C권6호
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• pp.769-778
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• 2003

XML 보안 명세 중 하나인 XML 키 관리 명세(XKMS)는 다양하고 복잡한 기능의 웹 서비스 애플리케이션에서 XML 문서의 서명을 검증하거나 암호화하는 공개키의 관리를 위한 프로토콜을 정의한다. 본 논문에서는 XML 표준 명세를 준수하는 XML 키 정보 프로토콜 서비스 모델을 제시하고, 표준에 근거한 프로토콜 컴포넌트의 참조 모델을 구현하였다. 또한 XML 기반 보안서비스 특성에 착안하여 안전한 XML 웹서비스를 위한 키 정보 서비스에 대한 분석과 보안 방안에 대해 기술한다. 프로토콜 컴포넌트는 식별정보가 주어졌을 때, 필요로 하는 공개키 위치와 식별자 정보, 공개키 연결 기능을 제공한다. 구현된 참조 모델은 향후 국내 e-비즈니스 프레임워크 구성 시 표준적인 보안 모델을 구현할 수 있는 지침을 제공할 것이다.