• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7A
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• pp.662-668
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• 2011

This paper analyzes the performance of the Ad hoc On-demand Distance Vector (AODV) routing protocol and Optimized Link State Routing (OLSR) for Mobile Ad hoc Networks (MANETs) using node mobility models. Mobility affects the performance of a routing protocol as it causes changes to network topology. Thus, evaluating the performance of a MANET routing protocol requires mobility models that can accurately represent the movements of mobile nodes. Therefore, this paper evaluates the performance of the AODV and OLSR routing protocols using the random way point model and the Levy walk model by the ns-2 simulations.

• ETRI Journal
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• v.34 no.6
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• pp.922-931
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• 2012

With the increasing demands for mobile wireless sensor networks in recent years, designing an energy-efficient clustering and routing protocol has become very important. This paper provides an analytical model to evaluate the power consumption of a mobile sensor node. Based on this, a clustering algorithm is designed to optimize the energy efficiency during cluster head formation. A genetic algorithm technique is employed to find the near-optimal threshold for residual energy below which a node has to give up its role of being the cluster head. This clustering algorithm along with a hybrid routing concept is applied as the near-optimal energy-efficient routing technique to increase the overall efficiency of the network. Compared to the mobile low energy adaptive clustering hierarchy protocol, the simulation studies reveal that the energy-efficient routing technique produces a longer network lifetime and achieves better energy efficiency.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.9
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• pp.4272-4286
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• 2016

In resource constrained sensor networks, usage of efficient routing protocols can have significant impact on energy dissipation. To save energy, we propose an energy efficient routing protocol. In our approach, which integrates clustering and routing in sensor networks, we perform network coding during data routing in order to achieve additional power savings in the cluster head nodes. Efficacy of the proposed method in terms of the throughput and end-to-end delay is demonstrated through simulation results. Significant network lifetime is also achieved as compared with other techniques.

• Journal of Communications and Networks
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• v.16 no.6
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• pp.613-619
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• 2014

Multicast routing algorithms designed for wireline networks are not suitable for wireless environments since they cannot efficiently exploit the inherent characteristics of wireless networks such as the broadcast advantage. There are many routing protocols trying to use these advantages to decrease the number of required transmissions or increase the reception probability of data (e.g., opportunistic routing).Reducing the number of transmissions in a multicast tree directly decreases the bandwidth consumption and interference and increases the overall throughput of the network. In this paper, we introduce a distributed multicast routing protocol for wireless mesh networks called NCast which take into account the data delivery delay and path length when constructing the tree. Furthermore, it effectively uses wireless broadcast advantage to decrease the number of forwarding nodes dynamically when a new receiver joins the tree.Our simulation results show that NCast improves network throughput, data delivery ratio and data delivery delay in comparison with on demand multicast routing protocol. It is also comparable with multichannel multicast even though it does not use channeling technique which eliminates the interference inherently.

• The KIPS Transactions:PartC
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• v.15C no.4
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• pp.289-296
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• 2008

In wireless mesh network, studies on routing protocols have been actively carried out recently, and hop count is used as a major routing metric in destination-sequenced distance-vector (DSDV) routing protocol, which is a representative proactive routing protocol. Although hop-by-hop multi-path (HMP) DSDV and enhanced HMP (EHMP) DSDV routing protocols perform routing by considering both hop count and residual bandwidth within one hop distance nodes, it has a shortcoming that routing is carried out via non-optimal path from the aspect of end-to-end routing. In order to overcome the shortcoming, a cost-aware multi-path (CAMP) DSDV routing protocol is proposed in this paper, which considers hop count and end-to-end minimum residual bandwidth. Simulation results based on NS-2 show that the proposed routing protocol performs better than DSDV, HMP DSDV, and EHMP DSDV protocols from the aspect of throughput and packet delivery ratio, by appropriately using hop count and end-to-end minimum residual bandwidth information and has the same number of management messages with HMP DSDV and EHMP DSDV protocols.

• Journal of Information Processing Systems
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• v.7 no.1
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• pp.29-42
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• 2011

Wireless sensor networks are composed of a large number of sensor nodes with limited energy resources. One critical issue in wireless sensor networks is how to gather sensed information in an energy efficient way, since their energy is limited. The clustering algorithm is a technique used to reduce energy consumption. It can improve the scalability and lifetime of wireless sensor networks. In this paper, we introduce a clustering protocol with mode selection (CPMS) for wireless sensor networks. Our scheme improves the performance of BCDCP (Base Station Controlled Dynamic Clustering Protocol) and BIDRP (Base Station Initiated Dynamic Routing Protocol) routing protocol. In CPMS, the base station constructs clusters and makes the head node with the highest residual energy send data to the base station. Furthermore, we can save the energy of head nodes by using the modes selection method. The simulation results show that CPMS achieves longer lifetime and more data message transmissions than current important clustering protocols in wireless sensor networks.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.477-480
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• 2000

Open Shortest Path First(OSPF) is a dynamic, hierarchical routing protocol designed to support routing in TCP/IP networks. Currently, OSPF is used as Interior Gateway Protocol(IGP) in many routers. In this paper, we analyze the variation of number of OSPF routing packets in case of changing the network configuration. The results show that the number of packets in case of adding new link increase five times than one in case of normal operation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.382-385
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• 2011

The sensor network technology for core technology of ubiquitous computing is in the spotlight recently, the research on sensor network is proceeding actively which is composed many different sensor node. One of the important condition for design of sensor node is to extend for network life which is to minimize power-consumption under the limited resources of sensor network. This study suggest routing protocol that was used second level cluster structure to reduce power-consumption of sensor node. the first level use the previous routing protocol under the LEACH, second level decide to transmit or not by comparision of data value for Effective Usage, reduce the unnecessary power-consumption.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.11
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• pp.4244-4274
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• 2021

The utilization of UAVs in various fields has led to the development of flying ad hoc network (FANET) technology. In a network environment with highly dynamic topology and frequent link changes, the traditional routing technology of FANET cannot satisfy the new communication demands. Traditional routing algorithm, based on geographic location, can "fall" into a routing hole. In view of this problem, we propose a geolocation routing protocol based on multi-agent reinforcement learning, which decreases the packet loss rate and routing cost of the routing protocol. The protocol views each node as an intelligent agent and evaluates the value of its neighbor nodes through the local information. In the value function, nodes consider information such as link quality, residual energy and queue length, which reduces the possibility of a routing hole. The protocol uses global rewards to enable individual nodes to collaborate in transmitting data. The performance of the protocol is experimentally analyzed for UAVs under extreme conditions such as topology changes and energy constraints. Simulation results show that our proposed QLGR-S protocol has advantages in performance parameters such as throughput, end-to-end delay, and energy consumption compared with the traditional GPSR protocol. QLGR-S provides more reliable connectivity for UAV networking technology, safeguards the communication requirements between UAVs, and further promotes the development of UAV technology.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.12
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• pp.5442-5463
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• 2016

Designing efficient routing protocols for a wireless sensor network with mobile sinks (mWSN) is a challenging task since the network topology and data paths change frequently as sink nodes move. In this paper, we design a novel lightweight reactive ring based routing protocol called R3, which removes the need of proactively maintaining data paths to mobile sinks as they move in the network. To achieve high packet delivery ratio and low transmission cost, R3 combines ring based forwarding and trail based forwarding together. To support efficient ring based forwarding, we build a ring based structure for a network in a way such that each node in the network can easily obtain its ring ID and virtual angle information. For this purpose, we artificially create a virtual hole in the central area of the network and accordingly find a shortest cycled path enclosing the hole, which serves as base ring and is used for generating the remaining ring based structure. We accordingly present the detailed design description for R3, which only requires each node to keep very limited routing information. We derive the communication overhead by ring based forwarding. Extensive simulation results show that R3 can achieve high routing performance as compared with existing work.