• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.139-142
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• 2010

클러스터 기반의 무선 센서 네트워크는 데이터를 병합하여 전송함으로써 에너지를 효율적으로 사용할 수 있다. 하지만 데이터를 병합하는 클러스터 헤드에 집중된 부하로 인해 센서노드 간 에너지 불균형이 발생하게 된다. 에너지가 고갈되어 가는 센서노드는 클러스터 헤드 선출기간에 필요한 메시지 전송에 따른 에너지 소모가 부담이 된다. 본 논문에서는 센서노드의 에너지가 고갈되어 갈 때 클러스터 선출에 발생하는 에너지 소모를 감소시키기 위해 클러스터 헤드 스케줄링 기법(Cluster Head Scheduling Scheme:CHSS)을 제안한다.

• Journal of Information Processing Systems
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• v.19 no.3
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• pp.377-384
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• 2023

The existence of abnormal breakpoint data leads to poor channel balance in wireless sensor networks (WSN). To enhance the communication quality of WSNs, a method for positioning abnormal breakpoint data in WSNs on the basis of signal reconstruction is studied. The WSN signal is collected using compressed sensing theory; the common part of the associated data set is mined by exchanging common information among the cluster head nodes, and the independent parts are updated within each cluster head node. To solve the non-convergence problem in the distributed computing, the approximate term is introduced into the optimization objective function to make the sub-optimization problem strictly convex. And the decompressed sensing signal reconstruction problem is addressed by the alternating direction multiplier method to realize the distributed signal reconstruction of WSNs. Based on the reconstructed WSN signal, the abnormal breakpoint data is located according to the characteristic information of the cross-power spectrum. The proposed method can accurately acquire and reconstruct the signal, reduce the bit error rate during signal transmission, and enhance the communication quality of the experimental object.

• The KIPS Transactions:PartC
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• v.16C no.4
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• pp.495-504
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• 2009

Wireless sensor networks (WSN) consisting of a largenumber of sensors aims to gather data in a variety of environments and is beingused and applied in many different fields. The sensor nodes composing a sensornetwork operate on battery of limited power and as a result, high energyefficiency and long network lifetime are major goals of research in the WSN. Inthis paper we propose a novel cluster-based local multi-hop routing protocolthat enhances the overall energy efficiency and guarantees reliability in thesystem. The proposed protocol minimizes energy consumption for datatransmission among sensor nodes by forming a multi-hop in the cluster.Moreover, through local cluster head rotation scheme, it efficiently manageswaste of energy caused by frequent formation of clusters which was an issue inthe existing methods. Simulation results show that our scheme enhances energyefficiency and ensure longer network time in the sensor network as comparedwith existing schemes such as LEACH, LEACH-C and PEACH.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.576-579
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• 2011

Wireless sensor network are widely all over different fields. Because of its distinguished characteristics, we must take account of the factor of energy consumed when designing routing protocol. Wireless sensor networks consist of small battery powered devices with limited energy resources. Once deployed, the small sensor nodes are usually inaccessible to the user, and thus replacement of the energy source is not feasible. Hence, energy efficiency is a key design issue that needs to be enhanced in order to improve the life span of the network. In BCDCP, all sensors sends data from the CH (Cluster Head) and then to the BS (Base Station). BCDCP works well in a smallscale network however is not preferred in a large scale network since it uses much energy for long distance wireless communication. TBRP can be used for large scale network, but it weakness lies on the fact that the nodedry out of energy easily since it uses multi-hops transmission data to the Base Station. Here, we proposed a routing protocol. A Cluster Based Energy Efficient Tree Routing Protocol (CETRP) in Wireless Sensor Networks (WSNs) to prolong network life time through the balanced energy consumption. CETRP selects Cluster Head of cluster tree shape and uses maximum two hops data transmission to the Cluster Head in every level. We show CETRP outperforms BCDCP and TBRP with several experiments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11A
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• pp.1064-1072
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• 2005

For the efficient operation of sensor networks, it is very important to design sensor networks for sensors to utilize their energies in very effective ways. Cluster-based routing schemes such as LEACH can achieve their energy efficiencies by delivering data between cluster heads and sensor nodes. In those cluster-based schemes, cluster reconfiguration algorithm is one of the most critical issues to achieve longer operation lifetime of sensor networks. In this paper, we propose a new energy efficient cluster reconfiguration algorithm. Proposed method does not require any location or energy information of sensors, and can configure clusters with fair cluster regions such that all the sensors in a sensor network can utilize their energies equally. The performances of the proposed scheme have been compared with LEACH and LEACH-C.

• Proceedings of the Military Operations Research Society of Korea Conference
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• 2005.03a
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• pp.143-153
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• 2005

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.5
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• pp.405-411
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• 2015

In this paper, we propose routing protocol for mobile wireless sensor networks with a mobile sink in cluster configuration. The proposed protocol extends LEACH-ME by introducing a mobile sink. The mobile sink moves to the cluster head with the highest number of member nodes to collect sensed data from cluster heads within its vicinity, which results in reducing energy consumption in forwarding packets to the sink. The simulation results show that the proposed protocol outperform LEACH-ME in terms of energy efficiency.

• Journal of Oral Medicine and Pain
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• v.39 no.3
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• pp.115-118
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• 2014

A 50-year-old female patient with severe unilateral pain in the right eye, head, and face accompanied by lacrimation and drooping of the right eye and rhinorrhea from the right nose, which developed immediately after extraction of the maxillary right first and second molars, was successfully treated with oral administration of sumatriptan and prednisolone, or verapamile. Although the clinical characteristics are similar to those reported in cluster headache except the temporal feature, the probable cluster headache, the hemicrania continua and the acute migraine headache should be included in the list of differential diagnoses.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.57-59
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• 2009

무선 메쉬 네트워크(Wireless Mesh Networks, WMNs)는 유비쿼터스 환경 및 무선 브로드밴드 액세스를 제공하기 위한 핵심적인 미래 기술로 대두되고 있다. WMN에서의 전체적인 성능은 채널의 간섭을 최소화함으로써 개선될 수 있다. 효율적인 채널 할당을 위해서는 채널 스캐닝 지연과 채널 의존성 문제를 고려해야 한다. 본 논문에서는 멀티채널 WMN에서의 이러한 문제점들을 해결하기 위해 클러스터 기반의 채널 할당(Cluster-Based Channel Assignment, CB-CA)을 제안한다. CB-CA에서는 클러스터 헤드 메쉬 라우터(Cluster Head Mesh Router, CHMR)들 간에는 동일 채널을 사용함으로써 채널 스캐닝과 채널 스위칭을 수행하지 않는다. 해당 클러스터 멤버 라우터(Cluster Member Mesh Router, CMMR)들과의 통신에는 CHMR들 간의 통신 채널에 영향을 미치지 않는 채널을 할당함으로써 멀티채널에서 발생할 수 있는 간섭을 최소화 할 수 있다.

• Journal of Internet Technology
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• v.19 no.6
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• pp.1801-1810
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• 2018

In this study, an energy-aware data-replication is proposed to effectively support a mobile sink in a solar-powered wireless sensor network (WSN). By utilizing the redundant energy efficiently, the proposed scheme shares the gathered data among the cluster heads using a backbone network, in order to increase data-reliability. It also maintains a backup cluster head in each cluster to enhance topological resilience. The simulation result showed that, compared to conventional clustering techniques, the proposed scheme decreases the total amount of data loss from the mobile sink as well as saving its energy (by reducing its moving distance), while minimizing the unexpected blackout time of the sensor node.