• Journal of KIISE:Information Networking
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• v.36 no.4
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• pp.322-329
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• 2009

Many researches in wireless sensor networks have used a geographic routing to effectively disseminate data between sinks and sources. To know the location information, the geographic routing has proposed two manners. A sink-initiated and a source-initiated are flooding to disseminate its location information in WSN. However, these two manners have two problems. Firstly, whenever they move, they flood their location information. Secondly, their location information is disseminated unnecessary nodes besides nodes which send and receive data in actually. Therefore, this paper proposes a protocol that can solve the two problems and disseminate effectively data between few sinks and few sources. The proposed protocol exploits a location information manager that manages location information of the sinks and the sources. We also compare the performance of the proposed protocol with the existing protocols through a simulation.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2007.11a
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• pp.377-382
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• 2007

Mobile ad hoc network(MANET) is a kind of wireless network which has no infrastructure. Each component node of MANET can move freely and communicate based on wireless peer to peer mode. Because of its vulnerable routing protocols, MANET is exposed to many kinds of attacks. A sinkhole attack is one of the representative attacks in MANET caused by attempts to draw all network traffic to a sinkhole node. This paper focuses on the sinkhole problem on Dynamic Source Routing(DSR) protocol in MANET. To detect the sinkhole node, we extract several useful sinkhole indicators through analyzing the sinkhole problem, then propose an efficient detection method based on an incremental learning algorithm. The simulation results show that the proposed method is effective and reliable for detecting sinkhole intrusion.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.386-388
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• 2010

에드 혹 네트워크(Ad hoc network)의 각 노드는 베터리 기반의 한정된 베터리로 동작하기 때문에 에너지 효율을 높이기 위한 다양한 라우팅 알고리즘이 연구되고 있다. 에드 혹 네트워크는 많은 수의 노드들이 거리 등의 상호 속성정보에 의한 노드의 관리기법에 따라 노드의 에너지를 관리해야 한다. 또한 주어진 망에서 관리 노드 또는 중계 노드 등이 동작 불가능한 상태가 되었을 경우 라우팅 경로가 끊어짐으로서 통신이 불가능한 상태가 되는 문제점이 있다. 본 논문에서는 트리망에서 중계 노드로 사용되는 클러스터 헤드 노드가 동작 불가능 상태가 되었을 경우, 노드간 거리 정보를 바탕으로 새로운 헤드 노드를 선출하는 ECDC(Energy Conservation Distance Control) 알고리즘을 제안하였다. 특히 제안된 ECDC 알고리즘을 이용함으로 노드에 대한 라이프타임을 향상 시키고 전체 라우팅 경로가 오랜 시간 동안 지속되는 결과를 보여주었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.3
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• pp.469-477
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• 2008

The standard routing protocol of MANET(Mobile Ad-hoc NETwork), AODV(Ad-hoc On-demand Distance Vector), only considers the shortest path for routing, which may cause traffic concentration to a node at the critical path. Hence, the battery of the node will be dissipated rapidly to reduce the lifetime of the whole network. In this paper, power dissipation considered AODV is proposed for fair energy distribution in MANET, and verified using the computer simulation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.9
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• pp.8-15
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• 2009

Although traditional single-hop cellular networks had been serving well in past years, they are no longer economically feasible in supporting high data-rate, multimedia services of $4^{th}$Generation (4G) communications due to the requirement of high transmission power By contrast, multi-hop cellular networks (MCN) are capable of dramatically saving the transmission power by overlaying the capability of ad hoc networking among mobile terminals on the cellular network infrastructure. To achieve this performance gain as well as enable 4G services, an efficient routing protocol needs to be designed for MCN. In this paper, we propose a reactive route discovery protocol for MCN that uses directional information to the base station in the route discovery process. Our analysis/simulation results have demonstrated that the proposed protocol significantly reduces flooding overheads. In addition, we consider issues for 4G services in MCN and applications of the proposed protocol.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.2
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• pp.46-49
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• 2010

This paper has proposedfor wireless Ad-hoc networks with robust route maintenance schemes. The device feature Bluetooth and/or IEEE 802.11 network interfaces and communicate in a decentralized manner. The nodes have the responsibility of self-organizing so that the network is robust to the variations in network topology due to node mobility as well as the fluctuations of the signal quality in the wireless environment.

• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.535-542
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• 2005

This paper proposes an on-demand ad hoc routing protocol, Node Density Based Routing (NDBR), which enhances the routing performance applying a new method to establish alternate patlis. It is important to reserve alternate paths for the route from source to destination in mobile ad hoc networks that are susceptible to failure due to the movement or the power exhaustion of mobile nodes. NDBR aims to establish a route that contains more alternate paths toward the destination by involving intermediate nodes with relatively more adjacent nodes in a possible route, and introduces a new routing criterion called 'node density.' This approach can localize the effects of route failures, and reduce control traffic overhead and route reconfiguration time by enhancing the reachability to the destination node without source-initiated route re-discoveries at route failures. This paper describes the route setup procedure using node density and the route re-configuration procedures employing alternate path information at the intermediate nodes. We show the performance of our routing schemes through a series of simulations using the Network Simulator 2 (ns-2).

• The KIPS Transactions:PartC
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• v.18C no.1
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• pp.15-22
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• 2011

Usually time synchronization is performed after routing tree is constructed. This thesis proposes a time synchronization algorithm combined with single-flooding routing tree construction algorithm in a single path. TSRA (Time Synchronization Routing Algorithm) uses routing packets to construct a routing tree. Two types of time information are added to the routing packet: one is the packet receiving time, and the other is the packet sending time. Time offset and transmission time-delay between parent node and child node could be retrieved from the added time information using LTS (Lightweight Time Synchronization) algorithm. Then parent node sends the time offset and transmission time to children nodes and children nodes can synchronize their time to the parent node time along the routing tree. The performance of proposed algorithm is compared to the TPSN (Timing-sync Protocol for Sensor Networks) which is known to have high accuracy using NS2 simulation tool. The simulation result shows that the accuracy of time synchronization is comparable to TPSN, the synchronization time of all sensor nodes is faster than TPSN, and the energy consumption is less than TPSN.

• Journal of KIISE:Information Networking
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• v.32 no.6
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• pp.745-752
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• 2005

BGP is a unique routing protocol in broadband internet. It chooses routing paths considering internet hierarchy and local policies. As BGP routers selectively bypass routing information to a subset of neighboring BGP routers, connectivity by way of a series of links between source and destination nodes does not mean reachability of routing information of the two. In emergency when BGP routers or links over wide range are not available, BGP routers have to use links that are not normally used to keep reachability. This paper listed out the requirements for BGP backup routing and proposed a routing solution that hides most demerits in currently published ones. The proposed backup operates in three tiers according to network damage. Under this rule, BGP routers use tier-0 routing paths at normal. If networks are impaired, they choose tier-1 paths. If networks are seriously damaged, tier-2 paths are allowed to use. Also this paper proves that the proposed backup guarantees stability and safeness. As results, the proposed backup is very adaptive to light network damages as well as serious ones and provides strong routing reachability at all times.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.860-863
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• 2005

Ad-Hoc networks are a new generation of networks offering unrestricted mobility without any underlying infrastructure. Primary applications of Ad-Hoc networks are in military, tractical and other security sensitive operations, where the environment is hostile. Hence, security is a critical issue. In this paper, we ahve identified certain misbehaviors caused by mallicious node for reactive routing protocol. We also discuss the intrusion detection and intrusion prevention model to prevent several identified attacks in the networks