• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.3
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• pp.163-169
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• 2016

To establish the equitable distribution of total energy load, a representative cluster based routing protocol LEACH selects cluster heads randomly in accordance with the pre-determined probability every round. But because the current energy level of sensor nodes is not considered, if a sensor node which has little residual energy is elected as a cluster head, it can not live to fulfil the role of cluster head which has big energy load. As a result, the first time of death of a node is quickened and the service quality of WSN gets worse. In this regard we propose a new routing method that, by considering the current energy of a cluster head and the distance between cluster heads and a base station, selects the sub cluster head for saving the energy of a cluster head. Simulation results show that the first time of death of a node prolongs, more data arrive at the base station and the service quality of WSN improves.

• International Journal of Computer Science & Network Security
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• v.23 no.1
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• pp.11-16
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• 2023

Vehicular networks are part of the next generation wireless and smart Intelligent Transportation Systems (ITS). In the future, autonomous vehicles will be an integral part of ITS and will provide safe and reliable traveling features to the users. The reliability and security of data transmission in vehicular networks has been a challenging task. To manage data transmission in vehicular networks, road networks are divided into clusters and a cluster head is selected to handle the data. The selection of cluster heads is a challenge as vehicles are mobile and their connectivity is dynamically changing. In this paper, a novel secure cluster head selection algorithm is proposed for secure and reliable data sharing. The idea is to use the secrecy rate of each vehicle in the cluster and adaptively select the most secure vehicle as the cluster head. Simulation results show that the proposed scheme improves the reliability and security of the transmission significantly.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.306-311
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• 2007

본 논문에서는 Wireless Sensor Network상에서 전체 노드들의 lifetime을 증대시키기 위하여 "random한" 방식으로 cluster-head를 선출하는 LEACH 알고리즘이 가지고 있는 cluster-head 선출 과정에서 선출되는 수와 선출되는 노드들의 위치가 적절히 분산되지 않는 문제를 해결하기 위해 변형된 Graph Coloring 문제를 기반으로 노드의 위치 정보를 사용하지 않고 cluster-head를 적절히 분산하여 선출함으로써 효율적인 clustering을 하는 중앙처리 방식의 새로운 알고리즘 "GCCA : Graph Coloring based Clustering Algorithm for Wireless Sensor Networks" 을 제안한다. GCCA는 cluster-head가 선출되는 수를 일정하게 유지하고 선출되는 노드의 위치가 전체 network area에 적절히 분산되는 효과를 가져 옴으로 LEACH 알고리즘보다 에너지 효율이 증대됨을 실험을 통하여 보인다.

• International journal of advanced smart convergence
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• v.5 no.1
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• pp.66-72
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• 2016

In this paper, we proposed the clustering algorithm using fuzzy inference system for improving adaptability the cluster head selection of TEEN. The stochastic selection method cannot guarantee available of cluster head. Furthermore, because the formation of clusters is not optimized, the network lifetime is impeded. To improve this problem, we propose the algorithm that gathers attributes of sensor node to evaluate probability to be cluster head.

• Convergence Security Journal
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• v.8 no.1
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• pp.91-100
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• 2008

The previous works in sensor networks security have focused on the aspect of confidentiality, authentication and integrity based on cryptographic primitives. There has been no prior work to assess the survivability in systematic way. Accordingly, this paper presents a survivability model of wireless sensor networks using software rejuvenation for dual adaptive cluster head. The survivability model has state transition to reflect status of real wireless sensor networks. In this paper, we only focus on a survivability model which is capable of describing cluster head compromise in the networks and able to switch over the redundant cluster head in order to increase the survivability of that cluster. Second, this paper presents how to enhance the survivability of sensor networks using software rejuvenation methodology for dual cluster head in wireless sensor network. We model and analyze each cluster as a stochastic process based on Semi Markov Process (SMP) and Discrete Time Markov Chain (DTMC). The proof of example scenarios and numerical analysis shows the feasibility of our approach.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.768-774
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• 2007

This paper proposes how to reduce the amount of data transmitted in each sensor and cluster head in order to lengthen the lifetime of sensor network. This study proposes hierarchical filtering for reducing the sensor's energy dissipation. Hierarchical filtering is to divide sensor network by two tiers when filtering it. First tier performs filtering when transmitting the data from cluster member to cluster head, and second tier performs filtering when transmitting the data from cluster head to base station. This should increase the efficiency of filtering and decrease the inaccuracy of the data compared to the methods which enlarge the filter width to do more filtering.

• The Research Journal of the Costume Culture
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• v.12 no.5
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• pp.757-768
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• 2004

This study was aimed to provide the fundamental and various measurement data of the head and face for Korean children. Two hundred sixty nine female children, aged nine to twelve years, participated for this study. The 28 regions on the head and face of the subjects were directly measured by the expert experimenters. Factor analysis, cluster analysis, GLM analysis and Tukey HSD test were performed' using these data. Through factor analysis, six factors were extracted upon factor scores and those factors comprised 71.42% for the total variances. Four clusters as their head and face shape were categorized using six factor scores by cluster analysis. Type 1 was characterized by the shorter head & face length and width and the lowest position from forehead to nose. Type 2 had the longer head & face length and width and the highest ear position and the largest mouse width. Type 3 was characterized by the longest and head & face type and the widest head & face girth. Type 4 was characterized by shortest head & face length the lower ear and lips position.

• Journal of the Korean Home Economics Association
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• v.42 no.6
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• pp.103-110
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• 2004

Among accessaries, headwear is important to protect one's face and head from the sun, wind and cold. This study was performed to provide fundamental data on college female students' head shape by classifying their head shapes and by analyzing the characteristics of each head shape in order to improve the fitness of headwear. The subjects were 193 Korean college female students. The subjects were directly measured anthropometrically and indirectly analyzed photo-graphically. By direct and indirect measurement, 5 factors were extracted through factor analysis and those factors comprised 76.34% of the total variance. 3 clusters as their head shape were categorized using 5 factor scores by cluster analysis. Type 1 was characterized by long head type and having smallest head thickness and head girth. Type 2 had average size and the most round-head type. Type 3 was characterized by short head type and the largest head thickness and head girth.

• The KIPS Transactions:PartC
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• v.17C no.3
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• pp.291-298
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• 2010

In wireless sensor networks, energy is the most important consideration because the lifetime of the sensor node is limited by battery. The clustering is the one of methods used to manage network energy consumption efficiently and LEACH(Low-Energy Adaptive Clustering Hierarchy) is one of the most famous clustering algorithms. LEACH utilizes randomized rotation of cluster-head to evenly distribute the energy load among the sensor nodes in the network. The random selection method of cluster-head does not guarantee the number of cluster-heads produced in each round to be equal to expected optimal value. And, the cluster head in a high-density cluster has an overload condition. In this paper, we proposed both a token based cluster-head selection algorithm for guarantee the number of cluster-heads and a cluster selection algorithm for uniform-density cluster. Through simulation, it is shown that the proposed algorithm improve the network lifetime about 9.3% better than LEACH.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.2
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• pp.75-82
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• 2014

MANET has various types of attacks. In particular, routing attacks using characteristics of movement of nodes and wireless communication is the most threatening because all nodes which configure network perform a function of router which forwards packets. Therefore, mechanisms that detect routing attacks and defense must be applied. In this paper, we proposed hierarchical structure attack detection techniques in order to improve the detection ability against routing attacks. Black hole detection is performed using PIT for monitoring about control packets within cluster and packet information management on the cluster head. Flooding attack prevention is performed using cooperation-based distributed detection technique by member nodes. For this, member node uses NTT for information management of neighbor nodes and threshold whether attack or not receives from cluster head. The performance of attack detection could be further improved by calculating at regular intervals threshold considering the total traffic within cluster in the cluster head.