• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2635-2643
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• 1997

In this paepr, a routing algorithm is proposed in order to reduce average end-to-end delay and congesting in the high speed network. The algorithm proposed here uses the existing one which adaptively modifies routes and the amount of traffic allocated to each link as user traffic partterns flutuate. This algorithm is ELB(Equitable Load Balancing). Also, the new algorithm considers the proportional to the distance between source and destination. It reduces congestion from the ELB and average end-to-end delay from the propagation dealy concepts respectively. Through the simulation, it shows that the algorithm proposed here reduces average end-to-end delay over low load to high load, and it also guarantees the congestion control.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1178-1181
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• 2009

Geographic forwarding algorithms을 사용하는 Georouting protocol에서는 route maintenance을 위해서 고정된 주기마다 beacon message을 이웃노드에 전송하는 fixed periodical beacon based route algorithm을 사용하여 mobile node 정보를 습득한다. Fixed periodical beacon scheme에서의 기존 연구 이슈는 이웃노드 정보의 신뢰성을 유지하기 위해서 다양한 mobility environment 환경에 맞도록 beacon 전송주기를 적절히 결정하는 연구가 진행되어 왔다. 이와 같은 연구에서는 long periodical interval 사용 시 이웃노드의 위치정보 error을 발생시킬 확률이 높으며 또한 short periodical interval 의 경우 네트워크 내에 high route overhead 을 유발시키는 단점을 가지고 있다. 따라서 고정된 주기 방법은 다양한 mobility environment에 잘 적용되지 못하며 또한 mobility environment 에서 발생하는 route maintenance 내에 이웃노드 정보에 대한 불확실성 문제가 빈번이 발생하여 경로 설정에 잘못된 정보를 제공하여 경로 신뢰성(path reliability)과 낮은 전송률 (transmission rate)을 야기한다. 본 논문에서는 이런 이웃노드 정보의 불확실성 문제를 극복하기 위해서 mobile node가 스스로 자신의 위치를 체크하여 routing table을 능동적으로 갱신하는 방법을 이용하여 이 문제를 극복할 수 있도록 하였다. 모의 실험은 ns2를 이용하여 실시하였으며 결과는 low/high mobility scenario에서는 기존 방법 보다 routing overhead 을 줄이면서 높은 전송률 (transmission rate)을 보인다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.3
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• pp.48-58
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• 2009

Geo-graphical routing protocols as GPSR are known to be very suitable and useful for vehicular ad-hoc networks. However, a corresponding node can include some stale neighbor nodes being out of a transmission range, and the stale nodes are pone to get a high priority to be a next relay node in the greedy mode. In addition, some useful redundant information can be eliminated during planarization in the recovery mode. This paper deals with a new recovery mode, the Greedy Border Superiority Routing(GBSR), along with an Adaptive Neighbor list Management(ANM) scheme. Each node can easily treat stale nodes on its neighbor list by means of comparing previous and current Position of a neighbor. When a node meets the local maximum, it makes use of a border superior graph to recover from it. This approach improve the packet delivery ratio while it decreases the time to recover from the local maximum. We evaluate the performance of the proposed methods using a network simulator. The results shown that the proposed protocol reveals much better performance than GPSR protocol. Please Put the of paper here.

• Journal of KIISE:Information Networking
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• v.31 no.3
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• pp.335-346
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• 2004

In this paper, we present a high-performance fault-tolerant switching networks using a deflection self-routing scheme, and present fault-diagnosis method for the network. We use the facts: 1) Each stage of the Banyan network is arrayed as the sequences of a Cyclic group of SEs. 2) There is the homomorphism between adjacent stages from a view of self-routing, so that all of each Cyclic group is the subgroup of the Cyclic group in the next stage, and there are factor groups due to such subgroup and homomorphism. We provide high-performance fault-tolerant switching networks of which the all links including augmented links are used as the alternate links detouring faulty links. We also present the fault diagnosis scheme for the proposed switching network that provide multiple paths for each input-output pair.

• Journal of the Korea Society of Computer and Information
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• v.17 no.6
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• pp.75-81
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• 2012

This paper has proposed Message Count Control Mechanism based Link State Update(LSU) Algorithm that has not had a strong influence on the depreciation of QoS routing performance. Most existing LSU algorithms have the limit that cannot control the count of LSU message. Especially, adaptive algorithms have a bad performance when traffic are excessive and fickle. We classify as the importance of LSU message that have a influence on available bandwidth and determine the transmission of the message according to update rate per a unit of time. 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 Korea Institute of Military Science and Technology
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• v.23 no.4
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• pp.371-380
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• 2020

Video is principal information that facilitates commander's immediate command decision. Due to fading characteristics of radio link, however, it is difficult to stably transmit video in a multi-hop wireless environment. In this paper, we propose a MANET structure composed of a link adaptive routing protocol and a TDMA MAC protocol to stably transmit video traffic in a ultra-narrowband video streaming network. The routing protocol can adapt to link state change and select a stable route. The TDMA protocol enables collision-free video transmission to a destination using multi-hop dynamic resource allocation. As a result of simulation, the proposed MANET structure shows better video transmission performance than proposed MANET structure without link quality adaption, AODV with CSMA/CA, and OLSR with CSMA/CA structures.

• Journal of the Korea Society for Simulation
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• v.18 no.3
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• pp.13-21
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• 2009

The sensor nodes that form a wireless sensor network must perform both routing and sensing roles, since each sensor node always has a regular energy drain. The majority of sensors being used in wireless sensor networks are either unmanned or operated in environments that make them difficult for humans to approach. Furthermore, since many wireless sensor networks contain large numbers of sensors, thus requiring the sensor nodes to be small in size and cheap in price, the amount of power that can be supplied to the nodes and their data processing capacity are both limited. In this paper, we proposes the WSN(Wireless Sensor Network) algorithm which is applied sensor node that has low power consumption and efficiency measurement. Moreover, the efficiency routing protocol is proposed in this paper. The proposed algorithm reduces power consumption of sensor node data communication. It has not researched in LEACH(Low-Energy Adaptive Clustering Hierarchy) routing protocol. As controlling the active/sleep mode based on the measured data by sensor node, the energy consumption is able to be managed. In the event, the data is transferred to the local cluster head already set. The other side, this algorithm send the data as dependent on the information such as initial and present energy, and the number of rounds that are transformed into cluster header and then transferred. In this situation, the assignment of each node to cluster head evenly is very important. We selected cluster head efficiently and uniformly distributed the energy to each cluster node through the proposed algorithm. Consequently, this caused the extension of the WSN life time.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.31-39
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• 2011

In this paper, we propose an evenly distributed mesh scheme to support services in mobile ad-hoc networks. Two strategies, the adaptive upgrading of forwarding nodes and the adaptive downgrading of forwarding nodes, are presented in the scheme. Our proposed scheme can support construction of better multicast mesh that can give higher packet delivery ratio with lower duplicate data as well as solve the problem of serious congestion especially when node mobility and data transmission rate are high in mobile ad-hoc networks. The performance evaluation is performed via simulation using OPNET.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.7
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• pp.1721-1736
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• 2013

Black and gray hole attack is one kind of routing disturbing attacks and can bring great damage to the network. As a result, an efficient algorithm to detect black and gray attack is important. This paper demonstrate an adaptive approach to detecting black and gray hole attacks in ad hoc network based on a cross layer design. In network layer, we proposed a path-based method to overhear the next hop's action. This scheme does not send out extra control packets and saves the system resources of the detecting node. In MAC layer, a collision rate reporting system is established to estimate dynamic detecting threshold so as to lower the false positive rate under high network overload. We choose DSR protocol to test our algorithm and ns-2 as our simulation tool. Our experiment result verifies our theory: the average detection rate is above 90% and the false positive rate is below 10%. Moreover, the adaptive threshold strategy contributes to decrease the false positive rate.

• The Journal of the Korea Contents Association
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• v.4 no.4
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• pp.113-121
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• 2004

Existing Cellular IP increases the network traffic load, packet loss and handoff latency because of duplicate packet. In this paper, we propose using a Combined Cache that unites a pasing cache with a routing cache and a Improved Adaptive Semi-soft handoff that minimizes to occur the duplicate packet. As a computer simulation, we consider packet loss, handoff latency and traffic load in network. In proportion the number of nodes, mobile hosts and downlinks of node in access network increased, the proposed method is largely improved in comparison with existing Cellular If that uses semi-soft handoff.