• Annual Conference of KIPS
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• 2011.11a
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• pp.1079-1081
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• 2011

컨테이너터미널 장치장 내 교차로에서 무인 YT(Yard Tractor)간 충돌방지를 위하여 RFID(Radio Frequency Identification) 태그와 ad-hoc 네트워크를 이용한 교차로 충돌방지 알고리즘을 제안한다. 또한 ad-hoc 네트워크 라우팅 프로토콜은 장치장 교차로에서 충돌방지를 위한 YT 간 통신성능을 결정하는 중요한 요소로써, 장치장 교차로 환경과 YT의 이동성을 고려하여 프로토콜을 결정해야 한다. 따라서 RFID 태그를 이용한 YT 위치정보와 AODV(Ad hoc On demand Distance Vector) 방식의 Hello 메시지를 이용해서 충돌방지를 위한 ad-hoc 네트워크 라우팅 프로토콜을 제안한다.

• Annual Conference of KIPS
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• 2008.11a
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• pp.1465-1468
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• 2008

모바일 에드혹 네트워크(MANET)에서 익명 라우팅을 위해 각 노드가 익명ID를 이용하여 MAC 단에서 익명으로 서로를 인증하고 네트워크 단에서 익명 라우팅 수행하는 AODV 기반의 라우팅 기법이 제안된바 있다[4]. 하지만 기존의 제안된 방법은 익명ID가 변경될 때마다 페어링 연산을 통해 재인증을 해야 하며, 라우팅 경로 중간의 노드들은 메시지의 연결성을 없에게 위해 매홉마다 암·복호화를 반복하여 상당히 비효율적이다. 본 논문은 기존논문의 노드 인증 기법을 확장하여 실제 메시지의 교환과정에서 일어나는 홉 간 암호화 횟수를 줄이고, 임시 인증값을 이용한 노드 상호간의 빠른 인증 기법을 사용하여 노드간의 인증과 익명성을 보장하는 보다 효율적인 프로토콜을 제안한다.

• Annual Conference of KIPS
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• 2008.11a
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• pp.1324-1327
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• 2008

본 논문에서는 무선 센서 네트워크의 에너지 제약 조건 및 지연을 개선하기 위하여 이웃 노드의 최단 홉 및 잔존 에너지를 이용한 라우팅 알고리즘을 제안하였다. 제안하는 알고리즘은 센서 네트워크의 대다수의 통신 방향이 데이터를 감지한 노드에서 싱크 노드라는 것을 고려하여 싱크노드에서 네트워크 셋업 시간에 각 노드들이 싱크노드로의 홉 수를 이웃노드 끼리 서로 공유할 수 있게 하여 라우팅 지연을 줄인다. 또한 라우팅 시 이웃노드의 배터리 상태를 고려할 수 있는 방법을 제안하여 전체 노드의 평균 수명을 늘일 수 있는 방법을 제시한다. 성능 비교를 위해 AODV와 Directed diffusion과 비교하여 네트워크 규모에 따른 지연시간 및 패킷 당 소모되는 배터리 소모량을 비교했을 때 제안하는 스킴이 우수하다는 것을 알 수 있다.

• Annual Conference of KIPS
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• 2007.11a
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• pp.1069-1072
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• 2007

MANET에서의 전통적인 라우팅 프로토콜은 일반적으로 두 종류로 나눠지는데 proactive 라우팅 프로토콜과 on-demand 라우팅 프로토콜이다. 라우팅 정보의 proactive 전파와 reactive 발견 사이에는 필수적인 trade-off 가 존재한다. 모든 시나리오들을 충족하는 라우팅 프로토콜이 존재하지 않는 것은 분명하다. 그래서 최적의 라우팅 프로토콜을 발견하기 위한 연구가 계속되고 있으며 IETF의 MANET 워킹그룹은 여러 다른 프로토콜을 제안 중에 있고 그 중에 하나가 on-demand 라우팅 프로토콜의 AODV를 계승한 DYMO(Dynamic MANET On-demand)이다. DYMO는 경로 축적 메커니즘을 채택하였다. 경로 발견 과정에서 노드들은 라우팅 메시지를 포워딩하기 전에 그들 자신의 라우팅 정보도 패킷에 추가할 수 있다. 결국 소스와 목적지 사이의 모든 노드들의 라우팅 정보가 교환되는 것이다. 이 논문에서는 이 경로 축적 메커니즘의 사용 유무에 따라 다양한 속도와 트래픽 부하에서 DYMO의 성능이 어떻게 변하고 최적의 환경은 무엇인지 연구해보고자 한다.

• Journal of KIISE:Information Networking
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• v.35 no.5
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• pp.409-414
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• 2008

In mobile ad hoc networks, most of on demand routing protocols such as DSR and AODV do not deal with traffic load during the route discovery procedure. To solve the congestion and achieve load balancing, many protocols have been proposed. However, the existing load balancing schemes has only considered avoiding the congested route in the route discovery procedure or finding an alternative route path during a communication session. To mitigate this problem, we have proposed a new scheme which considers the packet bursting mechanism in congested nodes. The proposed packet bursting scheme, which is originally introduced in IEEE 802.11e QoS specification, is to transmit multiple packets right after channel acquisition. Thus, congested nodes can forward buffered packets promptly and minimize bottleneck situation. Each node begins to transmit packets in normal mode whenever its congested status is dissolved. We also propose two threshold values to define exact overloaded status adaptively; one is interface queue length and the other is buffer occupancy time. Through an experimental simulation study, we have compared and contrasted our protocol with normal on demand routing protocols and showed that the proposed scheme is more efficient and effective especially when network traffic is heavily loaded.

• The KIPS Transactions:PartC
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• v.13C no.2 s.105
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• pp.219-226
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• 2006

The shortest path is only maintained during short time because network topology changes very frequently and each mobile nodes communicate each other by depending on battery in MANET(Mobile Ad-hoc Network). So many researches that are to overcome a limitation or consider a power have executed actively by many researcher. But these protocols are considered only one side of link stability or power consumption so we can make high of stability but power consumption isn't efficient. And also we can reduce power consumption of network but the protocol can't make power consumption of balancing. For that reason we suggest RBSSPR(Residual Battery Capacity and Signal Strength Based Power-aware Routing Protocol in MANET). The RBSSPR considers residual capacity of battery and signal strength so it keeps not only a load balancing but also minimizing of power consumption. The RBSSPR is based on AODV(Ad-hoc On-demand Distance Vector Routing). We use ns-2 for simulation. This simulation result shows that RBSSPR can extense lifetime of network through distribution of traffic that is centralized into special node and reducing of power consumption.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.3
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• pp.29-45
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• 2017

Ad hoc sensor network is characterized by decentralized structure and ad hoc deployment. Sensor networks have all basic features of ad hoc network except different degrees such as lower mobility and more stringent energy requirements. Existing protocols provide different tradeoffs among some desirable characteristics such as fault tolerance, distributed computation, robustness, scalability and reliability. wireless protocols suggested so far are very limited, generally focusing on communication to a single base station or on aggregating sensor data. The main reason having such restrictions is due to maximum lifetime to maintain network activities. The network lifetime is an important design metric in ad hoc networks. Since every node does a router role, it is not possible for other nodes to communicate with each other if some nodes do not work due to energy lack. In this paper, we suggest an experimental ad-hoc on-demand distance vector routing protocol to optimize the communication of energy of the network nodes.The load distribution avoids the choice of exhausted nodes at the route selection phase, thus balances the use of energy among nodes and maximizing the network lifetime. In transmission control phase, there is a balance between the choice of a high transmission power that lead to increase in the range of signal transmission thus reducing the number of hops and lower power levels that reduces the interference on the expense of network connectivity.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.6 s.324
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• pp.59-68
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• 2004

Thanks to the development of microelectromechanical systems(MEMS), wireless communication technology and microsensor technology, it was Possible to manufacture a very small and low costdata acquisition node with sensing function, processing function, wireless communication function and battery. Thus sensor networks begin to be prevailed. The sensor network is a spontaneous system which sets up automatically routing paths and transmits asignificant data to the destination. Sensor nodes requires low-power operation because most of them use a battery as operating power. Sensor nodes transmit a sensing data to the destination. Moreover, they play a router. In fact, because the later consumes more energy than the former, the low-power routing is very important. Sensor networks don't have a routing standard unlike general wireless Ad-hoc networks. So This paper proposes a low-power routing method for anting to sensor networks. It is based on AODV and adapts a method to drop probably RREQ depending on remaining power. We examined it through simulations. From simulation results, we could confirm to reduce power consumption about $10-20\%$ and distribute equally power consumption among nodes.

• Journal of the Korea Society of Computer and Information
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• v.15 no.12
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• pp.75-84
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• 2010

As broadcasting in Mobile Ad hoc NETwork (MANET) is the process that a node sends a packet to all other nodes in the network. it is used for routing protocols such as Ad hoc On demand Distance Vector (AODV) to disseminate control information for establishing the routes. In this paper, we propose Probabilistic Broadcasting mechanism based on Distance Ratio between sender and receive node in MANETs. The proposed approach is based on the combination of probability and distance based approach. A mobile node receiving broadcast packets determines the probability of rebroadcasting considering distance ratio from sender. The distance ratio of a node is calculated by the distance from sender and the length of radio field strength. As a node with high distance ratio is located far away from sender, rebroadcast probability is set to high value. On contrary, the low rebroadcast probability is set for a node with low distance ratio which is close to sender. So it reduces packets transmission caused by the early die-out of rebroadcast packets. Compared with the simple flooding and fixed probabilistic flooding by simulation, our approach shows better performances results. Proposed algorithm can reduce the rebroadcast packet delivery more than 30% without scanting reachability, where as it shows up to 96% reachability compared with flooding.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5B
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• pp.260-267
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• 2008

As pervious the SAR(Security Aware Routing)[10] protocol is an secure Ad Hoc network protocol that finds a secure path, it is the security routing protocol that uses the security level of nodes as the routing information. However, the SAR protocol sometimes transfers data through inefficient transmission paths because it always tries to find secure nodes for a safe transmission. Since it is a protocol based on AODV[6], it will cause transmission delay as researching of security routing path. when a node is out of the data transmission range as its battery dying or movement. Although it is possible to connection of nodes because a characteristic of the SAR protocol, the connection is not easy to reconnect when the security level of intermediate node is lower than the level requested by a source node. In this paper, we suggest the MP-SAR based on the SAR to solve the SAR protocol's problem. The MP-SAR seeks multiple secure path for maintenance of data confidentiality using the expanded secure path detection techniques based on the SAR. It can transfer data quickly and reliably by using the shortest efficient path among multiple paths. In the research result, we proved a outstanding performance of MP-SAR than the previous SAR through comparison and analysis.