• Journal of electromagnetic engineering and science
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• v.10 no.2
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• pp.56-60
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• 2010

This paper proposes a new cooperative protocol in which Alamouti's scheme is applied to exploit the advantages of both coded cooperation and Alamouti's scheme. It not only has better than direct transmission but also coded cooperation at appropriate cooperation levels. Simulation results show that the proposed protocol can save approximately 6~7 dB of transmit power to achieve the target BER(Bit Error Rate) compared with coded cooperation. Furthermore, the performance of the proposed protocol does not significantly depend on the qualities of inter-user channels.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.1
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• pp.78-85
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• 2008

In this paper, we propose the extension of cooperation protocol which realizes the autonomous control of QoS and show its effectiveness with implementation and experiments of our agent-based videoconference system. The autonomous QoS control in the agent-based videoconference system means the framework of adjusting its functions/abilities by itself to cope with the changes of user requirements and system resource situations. But, the original cooperation protocol used by the agent-based videoconference system is not enough to perform cooperation closely to use the limited resources effectively. In our proposal, the cooperation protocol is offended in the following points: (1) introducing a cooperation states, (2) extension of performatives, (3) introducing compromise levels. We embedded the proposed protocol to the agent-based videoconference system and experimented the behavior of the system. According to the experiments on this prototype system, we confirmed that the flexibility of the system is improved.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.05a
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• pp.167-170
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• 2001

인터넷 보안문제 해결을 위해서 침입탐지 시스템 및 바이러스 백신 등이 연구되어 왔고, 생체면역을 응용한 보안체계가 연구되고 있으나, 컴퓨터 자원소비와 비실시간대응의 문제점을 가지고 있다. 이에 Antibody Layer[1]는 인공면역과 Host alliance를 기반으로 하여 보안문제 해결에 효율성과 정확성을 제공하였다. 본 논문에서는 Antibody Layer의 Host alliance를 위한 Cooperation Protocol에 대하여 논하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.1
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• pp.24-29
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• 2011

Comparing conventional one-way relaying, two-way relaying scheme with network coding can achieve high throughput by reducing the transmission time. Coded cooperation protocol, which is a algorithm that uses coding on physical layer, can achieve high reliability. In this paper, we propose coded cooperation protocol over two-way relay network. Simulation results show proposed protocol has better performance in terms of reliability and throughput compare with conventional amplify and forward protocol. Also, with same throughput, proposed protocol has better performance in terms of reliability compare with the conventional hybrid decoded and forward protocol.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2384-2389
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• 2009

In this paper, we propose a lightweight mutual authentication protocol for secure and efficient home network service. Lee et al. recently proposed an attribute-base authentication key agreement protocol using public key in home network. Its protocol provided forward secrecy but don't diminish conspicious overhead of operation using ticket. Therefore the proposed protocol provided the security and efficiency using hash function and counter. Also it can provide secure home network service by check consumer electronics control level of users after created session key.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.2
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• pp.178-182
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• 2005

The proposed system in this paper is designed to provide users with a means of global location information using Orbcomm satellite communication and X.400 protocol. The system's two-way data transmission capabilities allow users to track mobile or fixed objects anywhere in the world via Internet. This study utilizes the X.400 protocol, and the SIP(Serial Interface Protocol) and self defined control protocol to implement data communication link in this paper. Data processor board connected to SC(Subscriber Communicator) is also designed and implemented to interface with GPS receiver. The experimental results of the proposed global position location system is evaluated through real-time experiments, and we have confirmed it works well according to the protocol designed in this paper.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4A
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• pp.345-355
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• 2011

This paper introduces the coded cooperation protocol in wireless relay network. We propose a two relay based coded cooperation protocol with RCPC codes for wireless networks. The proposed two-relay based system can achieve a diversity of order 4 under slow fading environment. Under fast fading, the diversity order is 2 times of the free distance of the convolutional code. We develop upper bounds on BER and FER for the system under both slow and fast fading with Rayleigh distribution. The effect of various channel conditions on the cooperation is also examined in this work.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.2
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• pp.370-376
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• 2009

Recently, Study for routing protocol is gone vigorously in the Ubiquitous Sensor Network. A hierarchical routing protocol is being practical and received interest among them. Therefore we analyze a weak point of HEED. And I suggest the new protocol that solved a weak point of HEED. The new protocol that we propose puts weight in the energy remainder amount than HEED and elect CH. And elected CH is designed to change by new node when quantity of energy leftover becomes less than 50%. Therefore all nodes come to use energy fairly. The protocol that we proposed can prove the cluster survival rate about 30%. And CH is more effective because when elect CH replace, response time selects small node.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.7
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• pp.1293-1310
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• 2011

A simple modification of well known Low Energy Adaptive Clustering Hierarchy (LEACH) protocol is proposed to exploit cooperative diversity. Instead of selecting a single cluster-head, we propose M cluster-heads in each cluster to obtain a diversity of order M. The cluster-heads gather data from all the sensor nodes within the cluster using same technique as LEACH. Cluster-heads transmit gathered data cooperatively towards the destination or higher order cluster-head. We propose a code combining based cooperative diversity protocol which is similar to coded cooperation that maximizes the performance of the proposed cooperative LEACH protocol. The implementation of the proposed cooperative strategy is analyzed. We develop the upper bounds on bit error rate (BER) and frame error rate (FER) for our proposal. Space time block codes (STBC) are also a suitable candidate for our proposal. In this paper, we argue that the STBC performs worse than the code combining cooperation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.2
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• pp.388-395
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• 2009

Three-party authenticated key exchange protocol based on smartcards using XOR and hash function operation instead of the public key operation has been proposed in 2006. Recently, it is doing for research because of increasing interest in privacy. This paper pointed out that proposed three-party authenticated key exchange protocol in 2006 has some problems; it is user anonymity and slow wrong input detection, and then we proposed new one to overcome these problems.