• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.105-107
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• 2015

In this paper, we proposed LTD(Load Tolerance Density-distribution) algorithm using dynamic density for analyzing distribute routing path. MANET(Mobile Ad-hoc Networks) consists of the node that has a mobility. By the Mobility, the topology is exchanged frequently. To reduce the exchange of topology, the hierarchy network is studied. However, if the load is concentrated at the cluster head node, the communication is disconnected. the proposed algorithm measure the dynamic density of the node using poisson distribution. And this algorithm provides distribute routing path using dynamic density. The simulation results, the proposed algorithm shows improved packet delivery ratio than the compared algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.197-203
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• 2011

Ad-hoc networks do not rely on a preexisting infrastructure such as Access Points(AP) in wireless network infrastructure. Instead each node participates in routing by forwarding data for other nodes. It makes required broadcasting to transmit packets to the whole network. In that part, each node tries to transmit data without any information about the other nodes. Therefore it causes duplication of transmission and waste of power. This paper presents adaptive probabilistic broadcasting schemes based on packet reception counts to alleviate the broadcast storm problem for wireless ad hoc networks. In this algorithm, each node calculates efficiency broadcast probability. Simulation results for the proposed flood algorithm are also presented.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.23-29
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• 2011

In some applications of wireless sensor networks, requirements such as energy efficiency, real-time, and reliable delivery need to be considered. In this paper, we propose a novel routing algorithm for wireless sensor networks. It provides real-time, reliable delivery of a packet, while considering energy awareness. In the proposed algorithm, a node estimates the energy cost, delay and reliability of a path to the sink node, based only on information from neighboring nodes. Then, it calculates the probability of selecting a path, using the estimates. When packet forwarding is required, it randomly selects the next node. A path with lower energy cost is likely to be selected, because the probability is inversely proportional to the energy cost to the sink node. To achieve real-time delivery, only paths that may deliver a packet in time are selected. To achieve reliability, it may send a redundant packet via an alternate path, but only if it is a source of a packet. Experimental results show that the proposed algorithm is suitable for providing energy efficient, real-time, reliable communications.

• Journal of KIISE:Software and Applications
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• v.36 no.5
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• pp.396-400
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• 2009

During periods of large data transmission, routing selection methods are used to efficiently manage data traffic and improve the speed of transmission. One approach in routing selection is AntNet that applies the Ant algorithm in transmissions with uniform probability. However, this approach uses random selection, which can cause excessive data transmission rates and fail to optimize data This paper presents the use of the Genetic Algorithm (GA) to efficiently route and disperse data transmissions, during periods with "unnecessary weight increases for random selection". This new algorithm for improved performance provides highly accurate estimates of the transmission time and the transmission error rate.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06a
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• pp.164-165
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• 2008

전장에서 임무 수행중인 병력이나 탱크 등을 지원하거나 보호 동물의 활동을 모니터링 하는 센서 네트워크에서는 전송 정보뿐만 아니라 그러한 대상들의 위치를 악의적 추적자로부터 보호할 수 있어야 한다. 본 논문에서는 활동 소오스 노드처럼 메시지 전송은 진행하고 있지 않지만 위치가 보호되어야 할 대상과 근접한 휴면(dormant) 소오스 노드들을 고려한 소오스 위치 보호 라우팅 기법 GSLP(GPSR-based Source-Location Privacy)를 제안한다. GSLP는 알고리즘의 간결성과 신장성(scalability)이 뛰어난 GPSR(greedy perimeter stateless routing)을 확장하여 메시지 전달 노드를 선정할 때 일정 확률로 임의의 이웃 노드를 선택하는 한편, perimeter 라우팅을 적용하여 소오스 노드들을 우회하도록 하여 위치를 보호하도록 하였다. 시뮬레이션 결과, 기존의 대표적인 소오스 위치 보호 라우팅 프로토콜인 PR-SP(Phantom Routing-Single Path)에 비해 GSLP는 휴면 소오스 노드들의 수에 거의 관계없이 높은 안전 기간(전송 메시지 수)을 일정하게 제공하면서도 전달 지연(경로의 평균 홉(hop) 수)은 도착지와의 최단 홉 수의 약 두 배 이내에 머물러 대규모 센서 네트워크에서의 소오스의 위치를 보호하기 위한 방안으로 적합한 것으로 평가되었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11B
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• pp.1030-1037
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• 2008

This paper presents an algorithm for the path-finding problem in unknown environments with cooperative and commutative multi-robots. To verify the algorithm, we investigate the problem of escaping through the exit of a randomly generated maze by muti-robots. For the purpose, we adopt the so called frontier cells and cell utility functions, which were used in the exploration problem for the multi-robots. For the wireless communications among the mobile robots, we modify and utilize the so called the random basket routing, a kind of hop-by-hop opportunistic routing. A mobile robot, once it finds the exit, will choose its next action, either escape immediately or stay-and-relay the exit information for the others, where the robot takes one action based on a given probability. We investigate the optimal probability that minimizes the average escaping time (out of the maze to the exit) of a mobile robot.

• Journal of KIISE:Information Networking
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• v.36 no.1
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• pp.12-23
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• 2009

Sensor networks deployed in battlefields to support military operations or deployed in natural habitats to monitor the rare wildlifes must take account of protection of the location of valuable assets(i.e., soldiers or wildlifes) from an adversary or malicious tracing as well as the security of messages in transit. In this paper we propose a routing protocol GSLP(GPSR-based Source-Location Privacy) that is capable of enhancing the location privacy of an active source node(i.e., message-originating node) in the presence of multiple dormant sources(i.e., nodes lying nearby an asset whose location needs to be secured). Extended is a simple, yet scalable, routing scheme GPSR(greedy perimeter stateless routing) to select randomly a next-hop node with a certain probability for randomizing paths and to perform perimeter routing for detouring dormant sources so that the privacy strength of the active source, defined as safety period, keeps enhanced. The simulation results obtained by increasing the number of dormant sources up to 1.0% of the total number of nodes show that GSLP yields increased and nearly invariant safety periods, while those of PR-SP(Phantom Routing, Single Path), a notable existing protocol for source-location privacy, rapidly drop off as the number of dormant sources increases. It turns out that delivery latencies of GSLP are roughly less than two-fold of the shortest path length between the active source and the destination.

• The Journal of the Korea Contents Association
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• v.9 no.3
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• pp.49-57
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• 2009

This paper has proposed Flow Holding Time based Link State Update(LSU) Algorithm that can improve the performance of the existing LSU algorithms. As the existing LSU algorithms are based on the network traffic information, the proposed algorithm is based on flow holding time so we can minimize the LSU message overhead and has not had a strong influence on the depreciation of QoS routing performance. We apply a flow holding time in order to decrease the number of LSU message. We have evaluated the performance of the proposed model and the existing algorithms on MCI simulation network using the performance metric as the QoS routing blocking rate and the mean update rate per link, it thus appears that we have verified the performance of this algorithm.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.10
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• pp.1-7
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• 2003

In this paper, we propose load balanced routing and wavelength assignment (RWA) algorithm for static model. The proposed algorithm arranges the routing paths over the link uniformly and assigns routing paths according to the length of routing paths orderly. Thus, the proposed algorithm can efficiently utilize the network resources. Through the computer simulation on layered-graph model, we prove that the proposed algorithm improves network throughput and reduces blocking probability comparing to first-fit algorithm [1］. Moreover, the proposed algorithm considerably reduces computational time.

• 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.