• Journal of KIISE:Databases
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• v.34 no.3
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• pp.261-269
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• 2007

As a basic research to integrate and to retrieve XML documents efficiently, this paper proposes a clustering method by structures of XML documents. We apply an algorithm processing the many transaction data to the clustering of XML documents, which is a quite different method from the previous algorithms measuring structure similarity. Our method performs the clustering of XML documents not only using the cluster histograms that represent the distribution of items in clusters but also considering the global cluster cohesion. We compare the proposed method with the existing techniques by performing experiments. Experiments show that our method not only creates good quality clusters but also improves the processing time.

• Computational Structural Engineering
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• v.22 no.6
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• pp.92-97
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• 2009

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.4
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• pp.313-320
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• 2008

The dynamic clustering technique has some problems regarding energy consumption. In the cluster configuration aspect the cluster structure must be modified every time the head nodes are re-selected resulting in high energy consumption. Also, there is excessive energy consumption when a cluster head node receives identical data from adjacent cluster sources nodes. This paper proposes a solution to the problems described above from the energy efficiency perspective. The round-robin cluster header(RRCH) technique, which fixes the initially structured cluster and sequentially selects duster head nodes, is suggested for solving the energy consumption problem regarding repetitive cluster construction. Furthermore, the issue of redundant data occurring at the cluster head node is dealt with by broadcasting metadata of the initially received data to prevent reception by a sensor node with identical data. A simulation experiment was performed to verify the validity of the proposed approach. The results of the simulation experiments were compared with the performances of two of the must widely used conventional techniques, the LEACH(Low Energy Adaptive Clustering Hierarchy) and HEED(Hybrid, Energy Efficient Distributed Clustering) algorithms, based on energy consumption, remaining energy for each node and uniform distribution. The evaluation confirmed that in terms of energy consumption, the technique proposed in this paper was 29.3% and 21.2% more efficient than LEACH and HEED, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.1013-1016
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• 2005

ZnO nanostructure was fabricated by catalyst-free method using Zn powder in air. The growth temperature was controlled from 450$^{\circ}$C to 600$^{\circ}$C, and the structural and optical properties were investigated by scanning electron microscopy (SEM), photoluminescence (PL), energy dispersive X-ray spectroscopy (EDX) and cathodoluminescence (CL). From all samples both ZnO tetrapods and clusters were observed. No significant dispersion was observed from the ZnO tetrapods, however, ZnO clusters show considerable change in density and size. From the EDX results, atomic composition difference was found. The clusters have O-deficiencies, while tetrapods have stoichiometric composition. Strong luminescence was observed at room temperature. From room temperature PL, UV emission at 380 nm and green emission at 500 nm were observed, and the intensity ratio ($I_{uv}/I_{green}$) increased as growth temperature increases. CL measurements show that the UV emission is closely related with tetrapods and the green emission is dominated from the clusters.

• Journal of the Korean Society for information Management
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• v.21 no.3
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• pp.251-267
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• 2004

The purpose of this study is to generate the local level knowledge structure of a single document, similar to end-of-the-book indexes and table of contents of printed material through the use of term clustering and cluster representative term selection. Furthermore, it aims to analyze the functionalities of the knowledge structure. and to confirm the applicability of these methods in user-friend1y information services. The results of the term clustering experiment showed that the performance of the Ward's method was superior to that of the fuzzy K -means clustering method. In the cluster representative term selection experiment, using the highest passage frequency term as the representative yielded the best performance. Finally, the result of user task-based functionality tests illustrate that the automatically generated knowledge structure in this study functions similarly to the local level knowledge structure presented In printed material.

• Journal of the Korean Academic Society of Industrial Cluster
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• v.2 no.1
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• pp.1-13
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• 2008

Despite growing recognition of the significance of industrial clusters to regional economic success, there has been only limited attention paid to the effectiveness of cluster policies in old industrial regions. Many of these regions still retain functioning industrial clusters, or have clusters which are adopting new strategies as part of a process of regeneration. This paper argues that the effectiveness of cluster policies in old industrial regions depends upon the extent to which they recognise the evolutionary nature of industrial clusters. It reviews the literature on the transformation of old industrial regions in Europe, and examines how cluster policies have risen to prominence as a policy tool. These strands ate brought together in an exploration of cluster policies in old industrial regions. A brief case study is presented of the evolution of the steel industry supply chain in north east England. The conclusions focus upon the data requirements that form a starting point for informed policy intervention into presses of cluster evolution.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.1
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• pp.38-43
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• 2011

Cluster-based routing is high energy consumption of cluster head nodes. A recent approach to resolving the problem is the dynamic cluster technique that periodically re-selects cluster head nodes to distribute energy consumption of the sensor nodes. However, the dynamic clustering technique has a problem that repetitive construction of clustering consumes the more energies. This paper proposes a solution to the problems described above from the energy efficiency perspective. The round-robin cluster header(RRCH) technique, which fixes the initially structured cluster and sequentially selects cluster head nodes, is suggested for solving the energy consumption problem regarding repetitive cluster construction. A simulation result were compared with the performances of two of the most widely used conventional techniques, the LEACH(Low Energy Adaptive Clustering Hierarchy) and HEED(Hybrid, Energy Efficient, Distributed Clustering) algorithms, based on energy consumption, remaining energy for each node and uniform distribution. The evaluation confirmed that in terms of energy consumption, the technique proposed in this paper was 26.5% and 20% more efficient than LEACH and HEED, respectively.

• Korean Journal of Environment and Ecology
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• v.26 no.4
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• pp.475-483
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• 2012

Tribolodon hakonensis(Cypriniformes; Leuciscinae) is anadromous; they are born in freshwater, migrate back to the ocean, then return to their home stream for spawning from mid-March to early-June. Here, five microsatellites were used to assess the level of gene flow among T. hakonensis populations from the Samcheok-Oship Stream, South Korea. The frequencies of dominant alleles across several loci differed between down-and upstream populations divided by several weirs, and pairwise multilocus $F_{ST}$ estimate was significantly high(0.083). However, there were no signs of any loss of genetic variation in the upstream population. Assignment tests of individuals in admixture model(K=2) to a set of baseline samples showed fairly correct assignment to each cluster; all of upstream individuals sere included in the first cluster, while the majority of downstream individuals(65%) comprise the second cluster. These results indicate reduced gene flow between up- and downstream populations but allowing passive downstream drift. It is likely that man-made structures might at least partially be a factor for creating and consolidating the current distribution patterns of genetic variation among T. hakonensis populations in the Samcheok-Oship Stream. This information will assist governing agencies in making informed decisions regarding conservation of anadromous fishes in Korean drainage systems.

• The KIPS Transactions:PartD
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• v.14D no.1 s.111
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• pp.1-8
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• 2007

As the web document of XML, an exchange language of data in the advanced Internet, is increasing, a target of information retrieval becomes the web documents. Therefore, there we researches on structure, integration and retrieval of XML documents. This paper proposes a clustering method of XML documents based on frequent structures, as a basic research to efficiently process query and retrieval. To do so, first, trees representing XML documents are decomposed and we extract frequent structures from them. Second, we perform clustering considering the weight of large items to adjust cluster creation and cluster cohesion, considering frequent structures as items of transactions. Third, we show the excellence of our method through some experiments which compare which the previous methods.

• Journal of Technology Innovation
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• v.27 no.3
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• pp.53-82
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• 2019

This study empirically conduct structural equivalence analysis based on social network analysis in picking up on overall structural characteristics of technological knowledge exchange in a regional cluster. Previous conceptual studies so far have argued that performance differences among structurally equivalent groups exist. However, because little research has been done to empirically investigate this conceptual hypothesis, this study is conducted as complementary to fill this void. For analysis, we utilize two-mode network data consisted of 2,550 firms by investigating 53 technological knowledge exchange-related associations within Gumi national industrial cluster. The results show that some structurally equivalent groups can be defined appropriately and its role can be conditioned by firms' salient characteristics attached to each structural equivalent groups. In addition, it is presented through the present study that performance difference in structural equivalent groups can be distinct by some selected performance indicators. Finally, this study suggests the need to advance the study of performance differences in structurally equivalent groups in the future.