• 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.

• Journal of KIISE
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• v.42 no.3
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• pp.408-412
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• 2015

In base station based networks, traffic overload at the base station is inevitable. Peer-to-peer DTN which disperses the traffic overhead to each node can relieve the traffic overload at the base station. To increase the message delivery ratio and reduce the message overhead, we present novel routing using mobility information which can be obtained from each node, unlike the existing flooding based routings. In the proposed routing scheme, the routing decision metric, which is defined based on the node mobility information, is computed by using the expected distance between each node to the destination. The message is copied to other nodes that have lower expected distance to the destination than the value for the node willing to copy the message. We conducted simulations by using both a random mobility model and a real mobility trace to compare the performance of the proposed routing scheme to the existing routing scheme that does not utilize the mobility information. The performance evaluation showed the proposed routing successfully delivers messages with 10% to 30% less copies compared to previously proposed routing schemes.

• Journal of the Korea Society of Computer and Information
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• v.14 no.12
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• pp.109-117
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• 2009

In this paper, we propose an efficient service discovery scheme that combines peer-to-peer caching advertisement and node ID-based selective forwarding service requests. P2P caching advertisement quickly spreads available service information and reduces average response hop count since service information store in neighbor node cache. In addition, node ID-based service requests can minimize network transmission delay and can reduce network load since do not broadcast to all neighbor node. Proposed scheme does not require a central lookup server or registry and not rely on flooding that create a number of transmission messages. Simulation results show that proposed scheme improved network loads and response times since reduce a lot of messages and reduce average response hop counts using adaptive selective nodes among neighbor nodes compared to traditional flooding-based protocol.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.154-156
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• 2006

These days wireless sensor networks receive much attention from industry and researchers on various fields. The challenge is that wireless sensor networks have limited resources. Nevertheless, the route discovery in ZigBee sensor networks is performed by simple flooding when the original racket is rebroadcasted at least once by every node in a network. Such uncontrolled flooding generates an excessive number of packets competing for the media and causes a high collision rate. In this article, we propose a suitable packet Time-To-Live value to solve problems of uncontrolled flooding in ZigBee networks. It is shown that more sufficient route discovery in a ZigBee network can save network resources and lengthen the life of a sensor network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.5
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• pp.857-859
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• 2015

In this letter, we consider a directional routing protocol that reduces the duplicated packets for AODV-based flooding in the course of establishing the end-to-end route in the multi-hop maritime ad-hoc networks. We propose an adaptive means of reducing the routing overhead subject to the node density and the target probability of successful routing that is analyzed by the stochastic geometry.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.8
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• pp.191-200
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• 2019

In an Ad-hoc network, a method of time synchronizing all the nodes in a network centering on one reference node can be used. A representative algorithm based on a reference node is Flooding Time Synchronization Protocol (FTSP). In the process of sending and receiving messages, predictable and unpredictable delays occur, which should be removed because it hinders accurate time synchronization. In multi-hop communications, hop delays occur when a packet traverses a number of hops. These hop delays significantly degrade the synchronization performance among nodes. Therefore, we need to find a method to reduce these hop delays and increase synchronization performance. In the FTSP scheme, hop delays can be greatly increased depending on the position of a reference node. In addition, in FTSP, a node with the smallest node ID is elected as a reference node, hence, the position of a reference node is actually arbitrarily determined. In this paper, we propose an optimal reference node election algorithm to reduce hop delays, and compare the performance of the proposed scheme with FTSP using the network simulator OPNET. In addition, we verify that the proposed scheme has an improved synchronization performance, which is robust to topology changes.

• Journal of Integrative Natural Science
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• v.1 no.3
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• pp.210-215
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• 2008

Ad hoc network는 무선 노드들의 집합으로서 어떤 인프라스트럭처 도움 없이 그들 서로가 multi-hop 경로를 통해 통신한다. 본 논문에서는 ad hoc network에서 사용되는 proactive 라우팅 프로토콜과 on-demand 라우팅 프로토콜의 혼합인 hybrid 라우팅 프로토콜에 대해 제안하였다. 본 논문에서는 기존의 hybrid 라우팅 프로토콜인 ZRP와는 달리 Ad hoc network를 구성하는 노드들 중에 네트워크 서비스를 제공해주는 특별한 노드를 설정하여 라우팅 하는 방법을 제안한다. 이러한 역할을 해주는 특별한 노드를 본 논문에서는 C-Node라 부른다. C-Node를 이용한 라우팅으로 기존의 라우팅 프로토콜보다 경로 설정 시간과 flooding 시간을 줄이므로서 효율적인 라우팅을 수행할 수 있게된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.3
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• pp.188-190
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• 2014

In mobile ad hoc networks(MANETs), each node rebroadcast received route request packets for route discovery. Flooding from large number of nodes induces the broadcast storm problem which causes severe degradation in network performance due to redundant retransmission, collision and contention. This paper presents a node status algorithm based on probabilistic scheme to alleviate the broadcast storm problem for wireless ad hoc networks.

• Annual Conference of KIPS
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• 2004.05a
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• pp.1429-1432
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• 2004

MANET(Mobile Ad Hoc Network)이란 어떠한 기반 구조나 중앙의 관리없이 동적으로 임시 네트워크를 형성하는 무선 mobile node의 집합이다. 이 논문에서는 MANET에서 근원지 node가 목적지 node로의 route를 발견하기 위해 전체 네트워크를 대상으로 route request 패킷을 flooding 할 경우 결과적으로 네트워크의 성능을 저하시킨다는 점과 mobile node가 제한된 양의 power를 가지고 있다는 점에 초점을 맞추어 연구가 진행되었다. 다시 말해 이 논문에서 제안된 ZTPA 라우팅 프로토콜은 기존의 ZRP를 기본으로 서로 겹치지 않는 격자 모양의 zone으로 네트워크가 구성된다. 또한 proactive 라우팅이 이루어지는 IARP에서 route 설정시 현재 node에 남아있는 power를 고려한 CMMBCR 라우팅 프로토콜이 사용되며 이와 더불어 두 개의 임계치(SVSZ, FVSZ)를 사용함으로써 설정된 route의 수명을 연장하고 신뢰성 있는 데이터 전송이 가능하여 전체적인 네트워크의 성능 향상을 야기할 수 있다.

• Journal of Korea Water Resources Association
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• v.40 no.4
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• pp.313-324
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• 2007

An irregular cell-based numerical model was developed to analyze underground space flooding. In this model, the flow characteristics in underground space were computed by link-node system. Also, the model can simulate the underground flood flow related to the influence of stairs and wall-structures. Empirical discharge formula were introduced to analyze weir-type flow for shopping mall, and channel-type flow for subway railroad respectively. The simulated results matched in reasonable range compared with the observed depth. The dual-drainage inundation analysis model and the underground space flood analysis model were integrated using visual basic application of ArcGIS system. The developed model can help the decision support system of flood control authority for redesigning and constructing flood prevention structures and making the potential inundation zone, and establishing flood-mitigation measures.