• 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.

• Journal of the Korea Society for Simulation
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• v.18 no.3
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• pp.47-59
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• 2009

Due to the application-specific nature of wireless sensor networks, the sensitivity to such a requirement as data reporting latency may vary depending on the type of applications, thus requiring application-specific algorithm and protocol design paradigms which help us to maximize energy conservation and thus the network lifetime. In this paper, we propose a novel delay-adaptive sensor scheduling scheme for energy-saving data gathering which is based on a two phase clustering (TPC). The ultimate goal is to extend the network lifetime by providing sensors with high adaptability to the application-dependent and time-varying delay requirements. The TPC requests sensors to construct two types of links: direct and relay links. The direct links are used for control and forwarding time critical sensed data. On the other hand, the relay links are used only for data forwarding based on the user delay constraints, thus allowing the sensors to opportunistically use the most energy-saving links and forming a multi-hop path. Simulation results demonstrate that cluster-based delay-adaptive data gathering strategy (CD-DGS) saves a significant amount of energy for dense sensor networks by adapting to the user delay constraints.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.742-745
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• 2006

센서 네트워크를 구성하는 각 노드는 크기가 작고, 배터리 용량도 제한되어 있기 때문에 오랜 시간 노드가 활동하기 위해서는 노드의 에너지 소모를 줄이는 것이 중요하다. 센서 노드들의 에너지 소비 감소를 위해서 센서 네트워크에서는 에너지 효율적인 라우팅을 통해 에너지를 소비를 줄이는 방법이 연구되었다. 그 중에서 클러스터링 기법은 센서 노드가 클러스터를 형성하고, 그 주체가 되는 클러스터 헤드와 통신함으로써 전체적인 센서 노드의 에너지 소비를 줄이고, 센서 노드의 에너지 소모를 분산하는 기법이다. 그러나 클러스터 생성 후 클러스터 내에서 센서 노드들이 직접 클러스터 헤드와 통신한다거나, 플러딩을 하는 방식으로 통신했을 때, 각각의 센서 노드들은 에너지 소비를 낭비한다. 이때 중요시 생각해야 할 것은 클러스터를 형성한 후, 클러스터 내에서 라우팅을 어떻게 하느냐가 클러스터 내에 있는 센서 노드들의 에너지 소비 분배를 효율적으로 할 수 있게 하는 가이다. 이에 본 논문은 초기 랜덤하게 뿌려진 센서 노들이 클러스터 헤드를 선정한 후, 클러스터 헤드로부터 클러스터를 형성하면서 생기는 정보를 바탕으로 클러스터 헤드로의 효율적인 라우팅 프로토콜을 하는 방법을 제안한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.11
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• pp.1170-1181
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• 2012

Wireless Sensor Networks(WSNs) are used in diverse applications. In general, sensor nodes that are easily deployed on specific areas have many resource constrains such as battery power, memory sizes, MCUs, RFs and so on. Hence, first of all, the efficient energy consumption is strongly required in WSNs. In terms of event states, event-driven deliverly model (i.e. surveillance and reconnaissance applications) has several characteristics. On the basis of such a model, clustering algorithms can be mostly used to manage sensor nodes' energy efficiently owing to the advantages of data aggregations. Since a specific node collects packets from its child nodes in a network topology and aggregates them into one packet to relay them once, amount of transmitted packets to a sink node can be reduced. However, most clustering algorithms have been designed without considering can be reduced. However, most clustering algorithms have been designed without considering characteristics of event-driven deliverly model, which results in some problems. In this paper, we propose enhanced clustering algorithms regarding with both targets' movement and energy efficiency in order for applications of surveillance and reconnaissance. These algorithms form some clusters to contend locally between nodes, which have already detected certain targets, by using a method which called CHEW (Cluster Head Election Window). Therefore, our proposed algorithms enable to reduce not only the cost of cluster maintenance, but also energy consumption. In conclusion, we analyze traces of the clusters' movements according to targets' locations, evaluate the traces' results and we compare our algorithms with others through simulations. Finally, we verify our algorithms use power energy efficiently.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.182-185
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• 2009

무선 센서 네트워크의 목적은 특정 지역에 뿌려져 있는 센서 노드를 통해서 센서 정보를 수집하는 것이다. 지역 내 센서 노드는 환경 값을 측정, 수집, 처리하여 싱크 노드로 전송된다. 이러한 과정은 센서네트워크를 구성하는 센서 노드의 제한된 능력 때문에 센서 노드의 저전력 동작 기법을 고려해야 한다. 인접한 센서 노드는 유사한 데이터를 가지기 때문에, 로컬 클러스터를 형성하고 클러스터 헤드로 데이터 가공 처리하는 클러스터링 기법이 저전력 동작 기법에 효과적이다. 또한 제한된 전송 범위에 따라 다중 홉 방식의 클러스터 형성 기법요구 된다. 클러스터 형성 시 클러스터 내 멤버 노드의 개수는 균형적인 클러스터 형성에 영향을 주기 때문에 클러스터를 균등하게 분할하는 방법이 필요하다. 이에 본 논문은 클러스터 헤드의 재선정을 통해 불균형하게 형성된 클러스터를 균등한 클러스터로 형성할 수 있는 방법을 제안한다.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.1
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• pp.22-30
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• 2008

Warehouse has many changes for the stocks by entering and taking. Management about the stocks is important. To manage, sensor network based on RFID is deployed in warehouse. Sensor network uses fluster based on energy and hierarchical routing. Supporting mobility between clusters makes guarantee connectivity for mobile nodes.

• Convergence Security Journal
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• v.16 no.2
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• pp.3-9
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• 2016

Recently, a lot of researches have been done to increase the life span of network using the energy efficient sensor node in WSN. In the WSN environment, we must use limited amount of energy and hardware. Therefore, it is necessary to design energy efficient communication protocol and use limited resources. Cluster based routing method such as LEACH and HEED get the energy efficient routing using data communication between cluster head and related member nodes. In this paper, we propose an energy efficient routing algorithm as well as performance result using simulation.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.4
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• pp.279-284
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• 2007

There ate various studies being conducted regarding efficient routing schemes to reduce energy consumption in the wireless sensor network, for which energy transformation is difficult. In terms of routing, many believe that the dynamic clustering technique is most efficient. The dynamic clustering technique consists of cluster construction and data transmission. Energy consumption for data transmission is proportional to $d^2$ and $d^4$ around the crossover area. This paper proposed algorithms for reducing energy consumption by improving efficiency of the cluster construction process that in the dynamic cluster mechanism and minimizing long-distance data transmission outside the crossover area. The proposed algorithms reduced energy consumption by implementing bridge clusters in the crossover area and decreasing the data transmission distance. The benefits of the proposed algorithms were confirmed through simulation experiments.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.3
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• pp.397-402
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• 2013

Time variation is the essential component of the context awareness. It is a beneficial way not only including time lapse but also clustering time interval for the context inference using the information from sensor mote. In this study, we proposed a novel way of clustering based multi-sensor data fusion for the context inference. In the time interval, we fused the sensed signal of each time slot, and fused again with the results of th first fusion. We could reach the enhanced context inference with assessing the segmented signal according to the time interval at the Dempster-Shafer evidence theory based multi-sensor data fusion.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.389-392
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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 technique. The sensed information in each cluster transfers to sink node through inter-cluster communications. Cluster head (CH) that nearby located in sink node much more spend own energy than far away CHs, because nearer CH forwards more data, so network lifetime is decreased. Proposed algorithm minimizes energy consumption in adjacent cluster to sink node by decreasing cluster site, and improve CH lifetime by distributing transmission paths. As a result of analysis, the proposed algorithm shows longer network lifetime in WSN.