• Journal of the Korea Society for Simulation
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• v.15 no.4
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• pp.87-96
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• 2006

Wireless Sensor Network (WSN) is researched in various filed. Underwater Sensor Network (UWSN) is used various purpose such as underwater environment monitoring. But, WSN is researched in the terrestrial that uses mainly radio frequency, The existing terrestrial research is incongruent to apply to underwater. Therefore, we propose UWSN architecture that considers underwater environment. In this paper, UWSN applied cluster technique and functional node constructs. Each cluster collects and sends cluster data. Dual super cluster head receives cluster data and transmits each in the base-station. We implement WSN routing algorithm, and construct test-bed and analyze cluster data receive rate.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.1
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• pp.87-93
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• 2013

MANET has the advantage of having the flexibility to build easily a network in a difficult situation that builds a wired network. But, data transmission errors by movement of nodes and eavesdropping by wireless communications have become a problem of security. Authentication service is the most essential in order to overcome these problems and operate network stably. In this paper, we propose 3-tiers authentication structure to exclude of malicious node and operate stable network through more systematic and thorough node authentication. After network is composed into a cluster, cluster head which play CA role is elected. Among these, the highest-CA is elected. The highest-CA receives certificates to cluster head and the cluster head evaluates trust value of their member nodes. Authentication technique which issues member node key is used. We compared PSS and experimented to evaluate performance of proposed scheme in this paper and efficiency of the proposed technique through experience was confirmed.

• Human Ecology Research
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• v.56 no.6
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• pp.603-617
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• 2018

This study analyzed research trends in the field of Practical Arts (Technology & Home Economics) education. From 958 articles published between 2010 and 2018 in the Journal of Korean Practical Arts Education (JKPAE), Journal of Korean Home Economics Education Association (JHEEA), and Korean Journal of Technology Education Association (KJTEA), 958 keywords were extracted and analyzed using NetMiner 4. When the general network structure was analyzed, keywords such as practical arts education, curriculum, textbook, home economics education, and students were high in the degree centrality and closeness centrality, and textbook, practical arts education, curriculum, student, home economics education, and invention were high in the node betweenness centrality. The cluster analysis showed that a four-cluster solution was most appropriate: cluster 1, technology and experiential learning activities; cluster 2, curriculum studies and practical problem; cluster 3, relationships; and cluster 4, creativity and character education. The three journals showed differences in the knowledge network structure: The topics of JKPAE and JKHEEA focused on general content knowledge and curriculum, while the topics of KJTEA were spread across invention and creativity education, and curriculum studies.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.91-105
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• 2010

A wireless sensor network communication technique has been broadly studied with continuous advances in ubiquitous computing environment. Especially, because the resource of the sensor node is limited, it is important to reduce the communication energy by using an energy-efficient routing protocol. The existing cluster-based routing protocols have a problem that they cannot select a cluster head efficiently by randomly choosing a head. In addition, because the existing cluster-based routing protocols do not support the large scale of network, they cannot be used for various applications. To solve the above problems, we, in this paper, propose a new cluster-based routing protocol using representative paths. The proposed protocol constructs an efficient cluster with distributed cluster heads by creating representative paths based on hop count. In addition, a new routing protocol supports multi-hop routing for data communication between a cluster member node and a cluster head as well as between cluster heads. Finally, we show that our protocol outperforms LEACH and Multihop-LEACH in terms of reliability and scalability.

• Journal of the Economic Geographical Society of Korea
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• v.15 no.4
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• pp.550-569
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• 2012

This paper studies the R&D network of the Zhongguancun Cluster, the most representative innovative cluster of the high-tech industry in China at present. For this study, Zhongguancun Cluster was the first high-tech cluster to have been created in China, the current Zhongguancun Cluster has played a leading role in the development of the high-tech industry in China. In addition, the Zhongguancun Cluster has at helped elevate China as a key region in terms of research development in relation to the high-tech industry. In particular, companies evaluate the research development network culture of Zhongguancun cluster positively and this increases their tendency to approach the research development network with an open mind. The main contents in research development network are as follows; (1) joint or consigned research development and technology transfer in the case of research development network between companies, (2) joint or consigned research development, human resource support and employment, technical advice and consultant and technology transfer in the case of industrial-educational relationships (3) joint or consigned research development, technical advice and consultant and technology transfer in the case of industrial-research relationships, (4) financial support and participation in joint research development project held by government in the case of industrial and governmental relationships (5) financing for research development, utilization of research human resources, purchase of research development and use of research development equipment for mediators. The main difficulties in creating a research development network are 'lack of mutual trust', 'financial problems of companies' and 'lack of information'. Especially, the main key obstacles for the most important research development network between industry and government in the case of the Zhongguancun Cluster are 'complicated and strict procedures. Therefore, more accurate and detailed understanding of the conditions and the following institutional measures from government are required for research development among companies.

• The KIPS Transactions:PartA
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• v.17A no.2
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• pp.103-112
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• 2010

Cluster sensor network is a sensor network where input nodes crowd densely around some nuclei. Steiner minimum tree is a tree connecting all input nodes with introducing some additional nodes called Steiner points. This paper proposes a mechanism for efficient construction of a cluster sensor network connecting all sensor nodes and base stations using connections between nodes in each belonged cluster and between every cluster, and using repetitive constructions of approximate Steiner minimum trees. In experiments, while taking 1170.5% percentages more time to build cluster sensor network than the method of Euclidian minimum spanning tree, the proposed mechanism whose time complexity is O($N^2$) could spend only 20.3 percentages more time for building 0.1% added length network in comparison with the method of Euclidian minimum spanning tree. The mechanism could curtail the built trees' average length by maximum 3.7 percentages and by average 1.9 percentages, compared with the average length of trees built by Euclidian minimum spanning tree method.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.1
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• pp.35-41
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• 2002

It is extremely important to minimize network access time in constructing a high-performance PC cluster system For an SCI based PC cluster it is possilbe to reduce the network access time by maintaining network cache in each cluster node, This paper presents a CC-NUMA card that utilizes network cache for SCI based PC clustering The CC-NUMA card is directly plugged into the PCI solot of each node, and contains shared memory network cache, and interconnection modules. The network cache is maintained for the shared memory on the PCI bus of cluster nodes. The coherency mechanism between the network cache and the shared memory is based on the IEEE SCI standard. A CC-NUMA prototype card is developed to evaluate the performance of the system. According to the experiments. the cluster system with the CC-NUMA card showed considerable improvements compared with an SCI based clustser without network cache.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.5
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• pp.199-202
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• 2013

In the cluster mechanism of the wireless sensor network, the network lifetime is affected by how cluster heads are selected. One of the representative clustering mechanisms, the low-energy adaptive clustering hierarchy (LEACH), selects cluster heads periodically, resulting in high energy consumption in cluster reconstruction. On the other hand, the adaptive clustering algorithm via waiting timer (ACAWT) proposes a non-periodic re-clustering mechanism that reconstructs clusters if the remaining energy level of a cluster head reaches a given threshold. In this paper, we propose a re-clustering mechanism that uses multiple remaining node energy levels and does re-clustering when the remaining energy level of a cluster head reaches one level lower. Also, in determining cluster heads, both of the number of neighbor nodes and the remaining energy level are considered so that cluster heads can be more evenly placed. From the simulations based on the Qualnet simulator, we validate that our proposed mechanism outperforms ACAWT in terms of the network lifetime.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.9
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• pp.772-779
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• 2012

In the current MANET, DOS or DDOS attacks are increasing, but as MANET has limited bandwidth, computational resources and battery power, the existing traceback mechanisms can not be applied to it. Therefore, in case of traceback techniques being applied to MANET, the resource of each node must be used efficiently. However, in the traceback techniques applied to an existing ad hoc network, as a cluster head which represents all nodes in the cluster area manages the traceback, the overhead of the cluster head shortens each node's life. In addition, in case of multi-hop clustering, as one Cluster head manages more node than one, its problem is getting even worse. This paper proposes TNA(Traceback against Network Attacks) based on multihop clustering using the depth of tree structure in order to reduce the overhead of distributed information management.

• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.139-148
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• 2008

The sensor network is applied from the field which is various. The sensor network nodes are exchanged with mobile environment and they construct they select cluster and cluster headers. In this paper, we propose the Dynamic Prediction Clustering Algorithm use to Skyline queries attributes in direction, angel and hop. This algorithm constructs cluster in base mobile sensor node after select cluster header. Propose algorithm is based made cluster header for mobile sensor node. It "Adv" reduced the waste of energy which mobile sensor node is unnecessary. Respects clustering where is efficient according to hop count of sensor node made dynamic cluster. To extend a network life time of 2.4 times to decrease average energy consuming of sensor node. Also maintains dynamic cluster to optimize the within hop count cluster, the average energy specific consumption of node decreased 14%.