• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.58-60
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• 2005

센서 네트워크를 구성하는 센서 디바이스 상에서 보안을 유지하는데 있어서 가장 까다로운 점은 센서 노드상에서 활용할 수 있는 대역폭, 에너지 저장용량 등과 같은 리소스가 다른 컴퓨팅 장비보다 월등히 적다는 점이다. 따라서 공격자는 센서 네트워크의 위와 같은 약점을 활용하는 다양한 공격을 시스템에 가할 수 있는데 그중 대표적인 방법이 시스템에 침투한 내부공격자에 의해서 변경된 가비지 데이터를 전송하게 항으로써 정상적인 노드들의 리소스를 낭비하게 하는 공격 방식이다. 따라서 본 논문에서는 기존의 연구됐던 보안 방식들이 내부공격자에 의한 전송계층상에서 취약한 정이 있음을 발견하고 접근 제어(access control)를 이용해서 이를 보완할 수 있는 방안을 제시한다. 이렇게 제시된 방안을 기존의 종단간 보안 프로토콜과 조합하면 아주 적은 양의 추가적인 오버헤드만으로 내부공격자에 대한 내구성을 더욱 강하게 할 수 있음을 실험을 통해 검증할 수 있다.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.3
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• pp.83-89
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• 2010

Scalable routing is one of the key challenges in designing and operating large scale MANETs. Performance of routing protocols proposed so far is only guaranteed under various limitation, i.e., dependent of the number of nodes in the network or needs the location information of destination node. Due to the dependency to the number of nodes in the network, as the number of nodes increases the performance of previous routing protocols degrade dramatically. We propose Cluster Overlay Dynamic Source Routing (CODSR) protocol. We conduct performance analysis by means of computer simulation under various conditions - diameter scaling and density scaling. Developed algorithm outperforms the DSR algorithm, e.g., more than 90% improvement as for the normalized routing load. Operation of CODSR is very simple and we show that the message and time complexity of CODSR is independent of the number of nodes in the network which makes CODSR highly scalable.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4A
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• pp.369-379
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• 2011

During the routing process between nodes on the CR(Cognitive Radio) network conducting for efficient use of limited frequency resources, spectrum handover process due to the appearance of the PU occupies most of the routing latency, and also decreases the reliability of the path. In this paper, a cooperative routing protocol in a multi-channel environment is proposed. The source node broadcasts a message with available channel lists and probability of PU appearance during its route guidance. The intermediate nodes re-transmit the message, received from the source node, and update and maintain the information, status table of the path. The destination node determines the optimal path and sends a reply message to the selected path after it receives the messages from the intermediate nodes. The average probability of the PU appearance and the average time of the PU appearance are updated while transferring data. During data transmission the channel with the lowest probability of appearance of the PU is selected dynamically and if a PU appears on the current channel partial repairment is performed. It is examined that reliability of the selected path considerably is improved and the routing cost is reduced significantly compared to traditional routing methods.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.5
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• pp.249-258
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• 2013

In multi-hop ad hoc networks, multi-interface multi-channel architecture is being noticing as methodology to improve the effective bandwidth and end-to-end throughput, But since existing routing metrics designed for networks based on single-interface exactly can not reflects the nature of networks based on multi-interface multi-channel, we are not expected the effect of throughput improvement. there had been proposal of MCR that discover high throughput by using metrics such as channel diversity and interface switching cost. however, MCR have an problem that is degraded it's performance in congested networks, because it not reflects the impact of traffic load. in this paper, we propose MAMCR metric, which select high throughput paths under congested conditions by combination MCR with channel access time metric, and conform it's the effect of performance improvement by ns-2 simulation.

• Journal of the Korea Society of Computer and Information
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• v.4 no.4
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• pp.163-169
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• 1999

Mobile-IP has been designed to have mobile computer users move from place to place without changing their IP addresses. Mobile-IP introduces the following entities to support mobility: Home Agent. Foreign Agent, etc., and it uses the techniques such as Agent Discovery, Registration. and Tunnelling. Mobile-IP route optimization provides a mechanism by which correspondent nodes are enable to know the mobile host's care-of address to alleviate the triangle routing problem. As a further performance improvement, to alleviate the overhead resulted from the frequent local mobility within a site hierarchical foreign agents are presented, and as a foreign agent which is willing to participate in communication maintain a buffering mechanism not to loss packets for mobile host, smooth handoffs is presented. In this paper, the problems to be thought to support host's mobility and the existing method to support it is discussed.