• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.311-315
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• 2010

대부분의 센서 네트워크는 주어진 제한된 용량의 배터리만으로 임무를 수혈해야 하므로 무선 센서 네트워크 분야에서 에너지 사용을 줄이기 위한 연구는 가장 중요한 문제중의 하나이다. 즉, 제한적인 에너지를 보유하고 있는 센서 네트워크에서 에너지 효율성을 극대화함으로써 네트워크 이용 가능 수명을 최대화할 수 있기 때문이다. 기존의 연구에서 이와 같은 네트워크 수명의 최대화를 추구해 왔다면, 본 논문에서는 네트워크가 형성된 후, 임무완료 전 수명이 종료되는 것을 막기 위해 추가적 노드 배포가 전체 네트워크 수명 연장에 미치는 효과를 연구하였다. 이를 위해 클러스터링 방식 에너지 효율적 라우팅 방법을 기본으로 하여 네트워크 수명 모델을 정의하였고, 이때 추가적으로 배포되는 노드의 분포에 따른 수명연장 효과를 조사하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.1207-1210
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• 2005

본 논문에서는 센서 네트워크에서 수명을 연장하기 위해 이동하는 모바일 싱크를 사용할 때 싱크가 이동함에 따라 늘어난 전체 네트워크 트래픽 량을 줄여 더욱더 수명을 연장하기 위해서 클러스터를 도입한다. 고정된 위치에서 싱크가 데이터를 수집할 경우 싱크 한 홉 내에 있는 노드들이 에너지를 빨리 소모하여 네트워크 파티션이 일어나기 쉽기 때문에 모바일 싱크를 사용하여 네트워크 수명을 연장하는 방법이 연구되었다. 이에 우리는 모바일 싱크가 이동하는 패턴이 주어지고 센서들로부터 매 T 마다 데이터를 받는다고 할 때 모바일 싱크와 클러스터를 함께 사용하였을 경우 네트워크 성능을 분석하고 에너지 효율적인 클러스터 형성 방법에 대해서 제안한다.

• Journal of Korea Multimedia Society
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• v.12 no.5
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• pp.728-736
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• 2009

We propose a method using the genetic algorithm to solve the maximum set cover problem. It is needed for scheduling the power of sensor nodes in extending the lifetime of the wireless sensor network with variable sensing range. The existing Greedy Heuristic method calculates the power scheduling of sensor nodes repeatedly in the process of operation, and so the communication traffic of sensor nodes is increased. The proposed method reduces the amount of communication traffic of sensor nodes, and so the energies of nodes are saved, and the lifetime of network can be extended. The effectiveness of this method was verified through computer simulation, and considering the energy losses of communication operations about 10% in the network lifetime is improved.

• Journal of the Korea Society of Computer and Information
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• v.15 no.6
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• pp.65-72
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• 2010

In ad-hoc network, the technique to efficiently consume the limited amounts of energy is an important issue since the wireless terminal node is operated on batteries as their energy resource. In order to extend the system lifetime, through a balanced energy consumption, we must delay the situation in which a particular terminal node's energy is depleted and results in system disconnection. Also, the link, which has low reliability due to the mobility of the node, should be avoided considering the key element when setting up the route. The proposed CMLR method in this paper enables to increase the efficiency of energy consumption with a new cost function considering the residue energy of node, error rate of link, and transmission energy consumption. This method is extending the network lifetime and increasing the energy efficiency by compromising the value between the minimization of the transmission energy consumption and maximization of the node's lifetime. Through the simulations the proposed CMLR algorithm was verified by showing better performance over the conventional methods in terms of network lifetime and path efficiency.

• The Journal of the Korea Contents Association
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• v.10 no.2
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• pp.120-129
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• 2010

MANET(Mobile Ad Hoc NETwork) is a collection of mobile nodes that are free to move and organize themselves in an arbitrary manner without any fixed infrastructures. These mobile nodes are connected by wireless links and act as routers for all other nodes in the network. As a router each node in MANET consumes its batteries when forwarding a message, and the selection of the best path to minimize the total power needed to route packets is needed to maximize the lifetime of all nodes. In this paper, we propose a routing protocol considering the remaining battery capacity of nodes in the routing paths. The proposed scheme prevents the battery of each node from being overused and increases the lifetime of the network.

• Journal of the Korea Society of Computer and Information
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• v.19 no.9
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• pp.65-73
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• 2014

Since Time synchronization is also critical in Wireless Sensor Networks (WSN) like other networks, a time synchronization protocol for WSN called IBS(Indirect-Broadcast Synchronization) has been already proposed in 2012. As IBS operates in cluster tree topology, network lifetime may be mainly shortened by cluster head node[s], which usually consumes more power than cluster member (i.e. non-cluster head) nodes. In this paper, I propose enhanced version of IBS (called EIBS) which saves overall energy and prolongs network lifetime by re-constructing partial cluster tree locally. Compared with other tree construction approaches, this tree reconstruction algorithm is not only simpler, but also more efficient in the light of overall power consumption and network lifetime.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.6
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• pp.1189-1194
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• 2005

An Ad-hoc network which do not use wired and base station system is composed the group of mobile and wireless nodes. That is various type of restriction. The biggest restriction is depend on the confined energy of battery. The network is devide more than two, if one of nodes consumed all energy that node can no longer participate to network. In recent years, the many number of studies research not only energy saving but also the networks lifetime extension which is to solve this problem. In this paper, we examine a AODV routing protocol which is modified to improve networks lifetime in mobile ad-hoc network. The one of improvement for AODV protocol is maximize the networks lifetime as apply Energy Mean Value algorithm which considerate node energy. We show the effectiveness for modified AODV(New-AODV) compared with AODV using NS-2(Network Simulator 2) the various performance metrics.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.6
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• pp.1201-1206
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• 2007

In this paper, we propose an algorithm that improve network lifetime by adjusting cluster size according to location information of sensor node in wireless sensor network (WSN) using clustering algorithm. The collected sensing information by sensor nodes in each cluster are transferred to sink node using inter-cluster communications method. Cluster head (CH) that located nearby sink node spend much more energy than those of far from sink node, because nearer CH forwards more data, so network lifetime has a tendency to decrease. Proposed algorithm minimizes energy consumption in adjacent cluster to sink node by decreasing cluster size, and improve CH lifetime by distributing transmission paths. As a result of mathematical analysis, the proposed algorithm shows longer network lifetime in WSN.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12B
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• pp.1083-1096
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• 2008

This paper proposes an energy-aware path management scheme, so-called the TBP(Threshold based Back-Pressure) algorithm, which is designed for lifetime extension of the energy-constrained wireless sensor networks. With the goal of fair energy consumptions, we extensively utilize the available paths between the source and the sink nodes. The traffic distribution feature of the TBP algorithm operates in two scales; the local and the whole routing area. The threshold and the back-pressure signal are introduced for implementing those operations. It is noticeable that the TBP algorithm maintains the scalability by defining both the threshold and the back-pressure signal to have their meanings locally confined to one hop only. Throughout several experiments, we observe that the TBP algorithm enhances the network-wide energy distribution. which implies the extension of the network lifetime. Additionally, both the delay and the throughput outcomes show remarkable improvements. This shows that the energy-aware path control scheme holds the effects of the congestion control.

• 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.