• The KIPS Transactions:PartC
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• v.16C no.4
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• pp.521-526
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• 2009

Disruption/Delay Tolerant Network(DTN) is a technology for interconnecting partitioned networks. These days, DTN, especially routing in DTN, draws significant attention from the networking community. In this paper, we investigate DTN routing strategies for highly partitioned ad hoc networks where Unmanned Aerial Vehicles (UAVs) perform store-carry-forward functionality for improved network connectivity. Also we investigate UAV trajectory control mechanisms via simulation studies.

• Journal of Digital Contents Society
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• v.15 no.1
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• pp.1-9
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• 2014

Delay-Tolerant Network (DTN) is an asynchronous networking technology that has been deployed for the networking environment in which steady communication paths are not available, and therefore it stores receiving data in a data storage and forward them only when the communication links are established. DTN can be applied to sensor networks and mobile ad-hoc network (MANET) as well as space communication that supports data transmissions among satellites. In DTN networking environments, it is very important to secure a scheme that has relatively low routing overhead and high reliability, so that it can enhance the overall routing speed and performance. In order for achieving efficient data transmissions among the nodes that have comparatively periodic moving patterns, this paper proposes a time information based DTN routing scheme which is able to predict routing paths. From the simulation results using Omnet++ simulation tools, it has been verified that the proposed time information based DTN routing algorithm shows satisfied levels of routing speed and routing reliability even with lower routing overheads.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.522-523
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• 2013

Delay Tolerant Network (DTN)란 노드 간 통신의 지연 시간이 길고 연결 단절이 자주 일어나는 네트워크 상황에서 데이터를 안정적으로 전달할 수 있도록 지원할 수 있는 네트워크를 말한다. DTN은 노드들 간의 연결 정도의 강약을 파악하여 연결 정도가 높은 노드를 통해 목적 노드로 메시지를 전달하는 방식을 사용한다. 노드들의 움직임이 빠르고 서로간의 거리가 멀어 지속적인 종단 간 연결성이 보장 되지 않는 상황일 때 DTN을 사용하면 안정적인 전송이 가능하다. 이때 이 노드들의 움직임을 예측 할 수 있다면 더 효과적인 메시지 전달이 가능 할 것이다. 이 논문에서는 이동 노드의 속도와 목적지 등과 같은 이동성 정보를 이용해 노드의 위치를 예측하여 효과적인 메시지 전달 경로를 결정하는 이동 예측 기반의 DTN 알고리즘을 제안한다. 이 알고리즘은 Mobility Strategy Sharing Location Service Protocol을 발전시켜 위치 정보 업데이트의 오버헤드를 최소화한다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.4
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• pp.13-28
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• 2009

Routing protocols in Delay/Disruption Tolerant Networks(DTN) are important to enhance the performance of transmission delay and delivery success ratio. In this paper, we propose an efficient DTN routing algorithm, called "Nobility Pattern based Routing(MPR)", that controls the total number of transferred message copies based on mobility patterns of mobile nodes. We consider a realistic "Levy walk" mobility pattern that has a super-diffusive property which well represents human mobility pattern. We implemented a DTN simulator using ONE simulator for the proposed MPR algorithm and Levy walk mobility pattern. Simulation results show that mobility patterns are very important for accurate evaluation of DTN routing performance, and the proposed MPR enhances the routing performance of delivery delay and success delivery ratio under realistic mobility pattern.

• International Journal of Computer Science & Network Security
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• v.22 no.2
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• pp.167-174
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• 2022

Vehicular Ad hoc Networks are considered as special kind of Mobile Ad Hoc Networks. VANETs are a new emerging recently developed, advanced technology that allows a wide set of applications related to providing more safety on roads, more convenience for passengers, self-driven vehicles, and intelligent transportation systems (ITS). Delay Tolerant Networks (DTN) are networks that allow communication in the event of connection problems, such as delays, intermittent connections, high error rates, and so on. Moreover, these are used in areas that may not have end-to-end connectivity. The expansion from DTN to VANET resulted in Vehicle Delay Tolerant Networks (VDTN). In this approach, a vehicle stores and carries a message in its buffer, and when the opportunity arises, it forwards the message to another node. Carry-store-forward mechanisms, packets in VDTNs can be delivered to the destination without clear connection between the transmitter and the receiver. The primary goals of routing protocols in VDTNs is to maximize the probability of delivery ratio to the destination node, while minimizing the total end-to-end delay. DTNs are used in a variety of operating environments, including those that are subject to failures and interruptions, and those with high delay, such as vehicle ad hoc networks (VANETs). This paper discusses DTN routing protocols belonging to unicast delay tolerant position based. The comparison was implemented using the NS2 simulator. Simulation of the three DTN routing protocols GeOpps, GeoSpray, and MaxProp is recorded, and the results are presented.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.404-407
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• 2014

Delay Tolerant Network (DTN) is a networking architecture that is designed to solve network problem in unstable and stressed environments using the Store-Carry-Forward method. Different form general networks, DTN does not guarantee the end-to-end connectivity, it is hard for the exiting TCP/IP based protocols to normally work due to the characteristic such as large latency and unstable link connectivity. And the condition that send massage without the information of the destination occurs frequently. Thus, suitable routing protocols for DTN are required and being researched. In this paper, we propose a novel routing protocol for DTN utilizing epidemic and prediction based algorithm to prevent the defect of previously DTN routing protocols such as the absence of the holistic view of the network. Proposed algorithm predicted destination using the mobility information recorded in neighbor node's history and utilize epidemic based algorithm when occurred condition without destination's information. This algorithm is enhanced in terms of delivery ratio, decreases latency and overhead in sparse network such as DTN.

• Journal of KIISE:Information Networking
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• v.36 no.2
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• pp.130-136
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• 2009

Delay and Disruption Tolerant Network (DTN) employs message delivery based on a store-and-forward method to conquer no guarantee of continuous end-to-end connectivity. Different from general networks, it is hard for the existing TCP/IP-based routing protocols to correctly work, due to the characteristics such as large latency and unstable link connectivity. Thus, many recent studies focus on routing protocols for DTN. In this paper, we propose a novel routing protocol for DTN with efficient message delivery utilizing mobility information such as direction or destination of mobile nodes. And this protocol is enhanced in terms of delivery ratio, decreases latency and overhead compared to the previously proposed solutions. Simulation results prove its superiority.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.120-122
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• 2015

In this paper, we proposed an algorithm of the unnecessary copied message inhibition using dynamic density what is called DDIM(Dynamic Density-based Inhibited Message diffusion) in DTNs(Delay Tolerant Networks). Existing DTN routing algorithms as Epidemic and Spray and Wait have some problems that occur large overhead in dense network due to the thoughtless message diffusion. Our proposed method, the DDIM, determines adjusted number of copied message through dynamic node density that is calculated using node's radio coverage and neighbor nodes in period time to solve message diffusion problem. It decrease overhead without losing message delivery ratio and increased latency through reducing message diffusion. In this paper, we compare delivery ratio, average latency and overhead of proposed algorithm, DDIM, and existing DTN routing algorithm and prove enhanced performance through simulation results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.431-433
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• 2016

In this paper, we propose an algorithm that analyzes characteristic nodes to select efficient relay nodes using message distribution. Existing delay-tolerant network (DTN) routing algorithms have problems with large latency and overhead on account of the deficiency of network information in an unsteady network. We must solve this problem, predict future networks using node state information, and apply a weight factor that changes according to the message distribution. Simulation results show that the proposed algorithm provides enhanced performance compared to existing DTN routing algorithms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.11
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• pp.2771-2778
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• 2014

In this paper, we propose an algorithm that select efficient relay nodes using information of network environment and nodes. The proposed algorithm can be used changeable weight factors as following network environment in node density. The routing protocols adopting store-carry-forward method are used for solving network problems occurred by unstable end-to-end connection in Delay Tolerant Networks(DTNs). Exiting DTN routing algorithms have problems that large latency and overhead because of deficiency of network informations. The proposed algorithm could be provide a solution this problems using changeable weight factor and prediction of network environment. Thus, selected relay nodes work efficiently in unstable and stressed network environment. Simulation results show that enhancement performance as overhead, delivery ratio, average latency compared to exiting DTN routing algorithm.