• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.6
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• pp.1169-1181
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• 1994

The Gamma Network contains the redundant path thereby is provides the ability to tolerate the faults occured. However, in case of identical the source and destination number, only a single path exists, therefore there is no way of connecting for the fault situation. In addition, for the dynamic packet routing strategy, it shoed perform backtracking analysis to find the redundant path. In this paper we proposed a new network, Dual Network, to resolve these drawbacks. The Dual Network uses switching elements about the same network size as the Gamma Network except first and last stage, and it is more efficient than the Gamma Network, for it has reduced the switching stage by one. And since is used a destination tag routing scheme for the control algorithm, it has on advantage of becoming of simpler and faster routing control.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11A
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• pp.1034-1042
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• 2008

It is very hard, but important to sustain path stability for a reliable communication in mobile ad hoc networks. We propose a novel source routing protocol that establishes a group path with virtual multiple paths to enable a robust communication. The entire mobile nodes form a disjoint set of clusters: Each has its clusterhead as a cluster leader and a unique cluster label to identify itself from other clusters. A group path is a sequence of cluster labels instead of nodes and the nodes with the same label collaborate to deliver packets to a node with next label on the group path. We prove by resorting to simulation that our proposed protocol outperforms the existing key routing protocols, even for a network with a high node mobility and a high traffic.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.728-731
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• 2008

Recently demands in construction of the stand-alone networks and interconnection between convergence devices have led an increase in research on IETF MANET working group, Bluetooth, and HomeRF working group and much attention has been paid to the application of MANET as a Ubiquitous network which is growing fast. With performance both as hosts and routers, easy network configuration, and fast response, mobile nodes participating in MANET are suitable for Embedded computing, but have vulnerable points, such as lack of network scalability and dynamic network topology due to mobility, passive attacks, active attacks, which make continuous security service impossible. For perfect MANET setting, routing is required which can guarantee security and efficiency through secure routing. In routing in this study, hashed AODV is used to protect from counterfeiting messages by malicious nodes in the course of path 'finding and setting, and disguising misrouted messages as different mobile nodes and inputting them into the network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.64-76
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• 2017

Routing in mobile ad hoc networks (MANETs) is highly challenging because of the dynamic nature of network topology. AntHocNet is a bio-inspired routing protocol for MANETs that mimics the foraging behavior of ants. However, unlike many other MANET routing protocols, the paths constructed in AntHocNet are unidirectional, which requires a separate path setup if a route in the reverse direction is also required. Because most communication sessions are bidirectional, this unidirectional path setup approach is often inefficient. Moreover, AntHocNet suffers from looping problems because of its property of multiple paths and stochastic data routing. In this paper, we propose a modified path setup procedure that constructs bidirectional paths. We also propose solutions to some of the looping problems in AntHocNet. Simulation results show that performance is significantly enhanced in terms of overhead, end-to-end delay, and delivery ratio when loops are prevented. Performance is further improved, in terms of overhead, when bidirectional paths setup is employed.

• Journal of the Korea Society for Simulation
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• v.19 no.2
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• pp.119-125
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• 2010

In ad-hoc networks, dynamically reconfigurable and temporary wireless networks, all mobile devices cooperatively maintain network connectivity with no assistance of base stations while they have limited amounts of energy that is used in different rates depending on the power level. Since every node has to perform the functions of a router, if some nodes die early due to lack of energy, it will not be possible for other nodes to communicate with each other and network lifetime will be shortened. Consequently, it is very important to develop a technique to efficiently consume the limited amounts of energy resources so that the network lifetime is maximized. In this paper, geographical localized routing is proposed to help making smarter routing decision using only local information and reduce the routing overhead. The proposed localized routing algorithm selects energy-aware neighbors considering the transmission energy and error rate over the wireless link, and the residual energy of the node, which enables nodes to achieve balanced energy-consumption and the network lifetime to prolong.

• The KIPS Transactions:PartC
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• v.14C no.5
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• pp.417-424
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• 2007

Mesh networks using WLAN technology have been paid attention as a key wireless access technology. However, many technical issues still exist for its successful deployment. One of those issues is the routing problem that addresses the path setup through a WLAN mesh network for the data exchanges between a station and a wired network. Since the characteristics of a WLAN mesh network can be very dynamic, the use of single routing protocol would not fit for all environments whether it is reactive or proactive. Therefore, it is required to develop an adaptive routing protocol that modifies itself according to the changes in the network parameters. As a logical first step for the development, an analytical model considering all the dynamic features of a WLAN mesh network is required to evaluate the performance of a reactive and a proactive routing scheme. In this paper, we propose an analytical model that makes us scrutinize the impact of the network and station parameters on the performance of each routing protocol. Our model includes the size of a mesh network, the density of stations, mobility of stations. and the duration of network topology change. We applied our model to the AODV that is a representative reactive routing protocol and DSDV that is a representative proactive routing protocol to analyze the tradeoff between AODV and DSDV in dynamic network environments. Our model is expected to help developing an adaptive routing protocol for a WLAN mesh network.

• Journal of Korea Multimedia Society
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• v.10 no.2
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• pp.269-277
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• 2007

Network clustering has been proposed to provide that sensor nodes minimize energy and maximize a network lifetime by configuring clusters, Although dynamic clustering brings extra overhead like as head changing, head advertisement, it may diminish the gain in energy consumption to report attribute tasks by using cluster heads. Therefore, this paper proposes a new routing algorithm which configures cluster to reduce the number of messages when establishing paths and reports to the sink by way of cluster heads when responding sens ing tasks. All sensor nodes only broadcast bitmap once and maintain a bitmap table expressed by bits, allowing them to reduce node energy and to prolong the network lifetime. After broadcasting, each node only updates the bitmap without propagation when the adjacent nodes broad cast same query messages, This mechanism makes nodes to have abundant paths. By modifying the query which requests sensing tasks, the size of cluster is designed dynamically, We try to divide cluster by considering the number of nodes. Then, all nodes in a certain cluster must report to the sub- sink node, The proposed routing protocol finds easily an appropriate path to report tasks and reduces the number of required messages for the routing establishment, which sensor nodes minimize energy and maximize a network lifetime.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12B
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• pp.1051-1059
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• 2003

The key feature of GMPLS is the provision of network resources and the automatic set-up of a path. And the mechanism of protection and restoration of a path is presented when network component fails. This paper suggests CR-LDP Static Detour Mechanism and Dynamic Detour Mechanism. CR-LDP Detours are a mechanism to set up detour paths automatically at every node to protect working path. Hence suggested mechanism performance is compared with existing mechanisms by computer simulation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.06a
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• pp.179-180
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• 2009

자동화 컨테이너 터미널의 생산성을 향상시키기 위해서는 안벽크레인의 작업 지연 시간을 최소화하는 것이 중요하다. 안벽크레인의 작업 지연 시간은 이송 차량들이 효율적으로 주행하여 제 시간에 필요한 위치에 컨테이너를 운반함으로써 단축이 가능하다. 이송차량의 주행 경로는 사전에 결정된 레이아웃에서 최단 거리, 최단 시간 경로 등의 라우팅 방법을 통해 결정된다. 주행 경로 레이아웃은 안벽크레인의 작업이 진행됨에 따라 안벽 크레인의 위치, 작업 물량 및 병목지점이 변화하므로 동적으로 조정한 필요가 있다. 본 논문에서는 안벽 크레인의 위치 변화에 따라 주행 경로 레이아웃을 동적으로 최적화하는 방안을 제안한다. 제안방안의 효율성은 시뮬레이션 실험을 통해 검증하였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.4
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• pp.180-187
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• 2002

Many real-time multimedia applications, such as video conferencing have stringent end-to-end delay constraints and consume large amount of network resources. In order to support these applications efficiently, multicast routing algorithms computing least cost multicast trees that satisfy a given end-to-end delay constraint are needed. However, finding such a tree is known to be computationally expensive. Therefore, we propose a heuristic distributed multicast routing algorithm that reduces a “finding multicast tree”that satisfies a given end-to-end delay constraint and minimizes the average resulting tree cost. Also, simulation results show that the proposed algorithm has much better average cost performance than other existing algorithms.