• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.386-388
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• 2010

에드 혹 네트워크(Ad hoc network)의 각 노드는 베터리 기반의 한정된 베터리로 동작하기 때문에 에너지 효율을 높이기 위한 다양한 라우팅 알고리즘이 연구되고 있다. 에드 혹 네트워크는 많은 수의 노드들이 거리 등의 상호 속성정보에 의한 노드의 관리기법에 따라 노드의 에너지를 관리해야 한다. 또한 주어진 망에서 관리 노드 또는 중계 노드 등이 동작 불가능한 상태가 되었을 경우 라우팅 경로가 끊어짐으로서 통신이 불가능한 상태가 되는 문제점이 있다. 본 논문에서는 트리망에서 중계 노드로 사용되는 클러스터 헤드 노드가 동작 불가능 상태가 되었을 경우, 노드간 거리 정보를 바탕으로 새로운 헤드 노드를 선출하는 ECDC(Energy Conservation Distance Control) 알고리즘을 제안하였다. 특히 제안된 ECDC 알고리즘을 이용함으로 노드에 대한 라이프타임을 향상 시키고 전체 라우팅 경로가 오랜 시간 동안 지속되는 결과를 보여주었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5B
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• pp.253-259
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• 2008

Because a sensor node in wireless sensor networks is battery operated and energy constrained, reducing energy consumption of each node is one of important issues. The clustering technique can make network topology be hierarchical and reduce energy consumption of each sensor node. In this paper, we propose an efficient clustering mechanism considering overlap avoidance in wireless sensor networks. The proposed method consists of three parts. The first is to elect cluster heads considering each node's energy. Then clusters are formed by using signal strength in the second phase. Finally we can reduce the cluster overlap problem derived from two or more clusters. In addition, this paper includes performance evaluation of our algorithm. Simulation results show that network lifetime was extended up to 75 percents than LEACH and overlapped clusters are decreased down to nearly zero percents.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.2
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• pp.103-112
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• 2010

In sensor networks, because sensors are deployed in an unprotected environment, they are prone to be targets of compromise attack, If the number of compromised nodes increases considerably, the key management in the network is paralyzed. In particular, compromise of Cluster Heads (CHs) in clustered sensor networks is much more threatening than that of normalsensors. Recently, rekeying schemes which update the exposed keys using the keys unknown to the compromised nodes are emerging. However, they cause some security and efficiency problems such as single group key employment in a cluster, passive eviction of compromised nodes, and excessive communication and computation overhead. In this paper, we present a proactive rekeying scheme using renewals of duster organization for clustered sensor networks. In the proposed scheme, each sensor establishes individual keys with neighbors at network boot-up time, and these keys are employed for later transmissions between sensors and their CH. By the periodic cluster reorganization, the compromised nodes are expelled from network and the individual keys employed in a cluster are changed continuously. Besides, newly elected CHs securely agree a key with sink by informing their members to sink, without exchangingany keying materials. The simulation results shows that the proposed scheme remarkably improves the confidentiality and integrity of data in spite of the increase of compromised nodes. Also, they show that the proposed scheme exploits the precious energy resource more efficiently than SHELL.

• Journal of Korea Multimedia Society
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• v.12 no.9
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• pp.1297-1308
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• 2009

The life time of a wireless sensor network composed of numerous sensor nodes depend on ones of its sensor nodes. The energy efficiency operation of nodes, therefore, is one of the crucial factors to design the network. Researches based on the hierarchical network topology have been proposed and evolved in terms of energy efficiency. However, in existing researches, application layer data obtained from sensor nodes are not considered properly to compose cluster, including issue that nodes communicate with their cluster heads in TDMA scheduling. In this paper, we suggest an energy-efficient topology control scheme based on application layer data in wireless sensor networks. By using application layer data, sensor nodes form a section which is defined as the area of adjacent nodes that retain similar characteristics of application environments. These sections are further organized into clusters. We suggest an algorithm for selecting a cluster head as well as a way of scheduling to reduce the number of unnecessary transmissions from each node to its cluster head, which based on the degree and the duration of similarity between the node's data and its head's data in each cluster without seriously damaging the integrity of application data. The results show that the suggested scheme can save the energy of nodes and increase the life time of the entire network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.227-230
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• 2011

In this paper, we are proposed ECOPS(Energy Conserving optimal Path Schedule) algorithm that according to ALPS(Ad hoc network Localized Positioning System) algorithm the location information is received and the new head node is selected considering the energy efficiency. The proposed algorithm follows RODMRP(Resilient Ontology-based Dynamic Multicast Routing Protocol) structure, that is the hierarchic cluster structure. And by using the location information of the node, it maintains the cluster which the energy is efficient with the production. It increases the life time of the total routing structure.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.820-823
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• 2011

WSN is composed of a lot of small sensors with the limited hardware resources. In WSN, at the initial stage, sensor nodes are randomly deployed over the region of interest, and self-configure the clustered networks by grouping a bunch of sensor nodes and selecting a cluster header among them. In this paper, we propose a self-configuration routing protocol for WSN, which consists of step-wise ripple routing algorithm for initial deployment, effective joining of sensor nodes. RRA is search node in RF-coverage of each node, which result in fast network connection, reducing overall power consumption, and extending the lifetime of network.

• Journal of the Korea Society of Computer and Information
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• v.19 no.6
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• pp.49-59
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• 2014

Recently, wireless sensor networks(WSNs) are widely used for intrusion detection and ecology, environment, atmosphere, industry, traffic, fire monitoring. In this paper, an energy efficient clustering algorithm is proposed. The proposed algorithm forms clusters uniformly by selecting cluster head that optimally located based on receiving power. Besides, proposed algorithm can induce uniform energy consumption regardless of location of nodes by multi-hop transmission and MST formation with limited maximum depth. Through the above, proposed algorithm elongates network life time, reduces energy consumption of nodes and induces fair energy consumption compared to conventional LEACH and HEED. The results of simulation show that the proposed clustering algorithm elongates network life time through fair energy consumption.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.1
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• pp.233-241
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• 2013

One fundamental issue in ad hoc networks is the alternative node election problem, which reflects how well a sensor network is monitored or tracked by sensors. In this paper, we proposed EEAP(Energy-Efficient Alternative Paths). This is a method of selecting an alternative node for path routing management. When some node disconnection on the path routing, using pre-selected backup node provides immediately recover the path recovery. When selecting an alternative node of Step-Parents head node on the path management, the node's energy level and distance information are cared in context-awareness. This is not only increased the system's capacity cost effectively, but also reduce transmission power entire nodes consume energy. As a result, each node could efficiently management and improves the life time for mobile host and extends system coverage.

• Journal of Korea Multimedia Society
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• v.12 no.9
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• pp.1273-1287
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• 2009

PEGASIS, a chain-based protocol, forms chains from sensor nodes so that each node transmits and receives from a neighbor. In this way, only one node (known as a HEAD) is selected from that chain to transmit to the sink. Although PEGASIS is able to balance the workload among all of the nodes by selecting the HEAD node in turn, a considerable amount of energy may be wasted when nodes which are far away from sink node act as the HEAD. In this study, DERP (Distance-based Energy-efficient Routing Protocol) is proposed to address this problem. DERP is a chain-based protocol that improves the greedy-algorithm in PEGASIS by taking into account the distance from the HEAD to the sink node. The main idea of DERP is to adopt a pre-HEAD (P-HD) to distribute the energy load evenly among sensor nodes. In addition, to scale DERP to a large network, it can be extended to a multi-hop clustering protocol by selecting a "relay node" according to the distance between the P-HD and SINK. Analysis and simulation studies of DERP show that it consumes up to 80% less energy, and has less of a transmission delay compared to PEGASIS.