• Journal of Engineering Education Research
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• v.8 no.1
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• pp.31-45
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• 2005

In this paper, selecting survey items was performed using three clustering methods: factor analysis, fuzzy c-Means algorithm and cluster analysis. The methods were used to extract key items from various questionnaires. The key item represents several similar questionnaires that form a cluster. Test survey was made of 120 items obtained from several surveys and it was answered by 646 students from 4 universities. Each item contains 6 choices. Applying the clustering method chose 25 items which is reduced from the original 120 items. The results yielded by three methods are very similar.

• Smart Media Journal
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• v.2 no.3
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• pp.17-22
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• 2013

The growth of the propagated NFC provides the various services with respect to internet applications, which it can be predicted from the simple internet services to the privated services. This paper proposes the clustering of information retrieval system model using NFC tag of access information for utilizing the similar information of the tag. The proposed model can search the similar information of the tag using the access information of NFC tag. In addition, it can cluster the similar retrieval information into topic cluster for utilizaing users.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.53.1-53.1
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• 2011

We analyze the halo and galaxy catalogs from the Millennium simulations at redshifts z=0, 0.5, 1 to determine the alignment profiles of cluster galaxies in terms of the matter density correlation coefficient and discuss a cosmological implication our result has for breaking parameter degeneracies. For each selected cluster, we measure the alignment between the major axes of the pseudo inertia tensors from all satellites within cluster's virial radius and from only those satellites within some smaller radius. Then we average the measured values over the similar-mass sample to determine the cluster galaxy alignment profile as a function of top-hat scale difference at each redshift. It is shown that the alignment profile of cluster galaxies is well approximated by a power-law of the nonlinear density correlation coefficient that is independent of the power spectrum normalization and bias factor. The alignment profile of cluster galaxies is found to have higher amplitude and lower power-law index when averaged over the larger-mass sample and to have rather weak redshift-dependence. This result is consistent with the picture that the satellite galaxies retain the memory of the external tidal fields right after merging and infalling into the clusters but they gradually lose the initial alignment tendency as the cluster's relaxation proceeds. Demonstrating that the nonlinear density correlation coefficient varies sensitively with the density parameter and neutrino mass fraction, we discuss a potential power of the cluster galaxy alignment profile as an independent probe of cosmology.

• Journal of Preventive Medicine and Public Health
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• v.30 no.1 s.56
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• pp.181-193
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• 1997

The purpose of this study was to identify population subgroups with similar patterns of diet quality, physical activity, alcohol consumption and cigarette smoking of Korean. The cluster analysis was conducted using the data from Korea National Health Survey(KNHS) in 1995, which consisted of 5,805 persons. We identified six health behavior typologies : 32.9% of the sample had a good diet but sedentary activity level(good diet lifestyle), 7.2% had high activity level but less diet quality(fitness lifestyle). Individuals in the passive lifestyle cluster(39.1%) had no active health promoting activities but tended to avoid risk taking health behavior such as cigarette smoking and alcohol drinking. 1.1% of the sample were in a drinking cluster, 17.2% in a smoking cluster and 2.5% had a hedonic lifestyle characterized by heavy drinking and smoking. The other characteristics of these lifestyle clusters could be presented by demographic and socioeconomic factors.

• Journal of information and communication convergence engineering
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• v.17 no.3
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• pp.185-190
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• 2019

The explosive growth of data traffic and services has created cost challenges for networks. Studies have attempted to effectively apply network slicing in fifth generation networks to provide high speed, low latency, and various compatible services. However, in network slicing using mixed-integer linear programming, the operation count increases exponentially with the number of physical servers and virtual network functions (VNFs) to be allocated. Therefore, we propose an efficient slice allocation method based on cluster technology, comprising the following three steps: i) clustering physical servers; ii) selecting an appropriate cluster to allocate a VNF; iii) selecting an appropriate physical server for VNF allocation. Solver runtimes of the existing and proposed methods are compared, under similar settings, with respect to intra-slice isolation. The results show that solver runtime decreases, by approximately 30% on average, with an increase in the number of physical servers within the cluster in the presence of intra-slice isolation.

• The KIPS Transactions:PartB
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• v.9B no.1
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• pp.113-118
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• 2002

This paper presents a cluster-based image retrieval method. It retrieves images from a related cluster after classifying images into clusters using RAGMD, a clustering technique. When images are retrieved, first they are retrieved not from the whole image database one by one but from the similar cluster, a similar small image group with a query image. So it gives us retrieval-time reduction, keeping almost the same precision with the exhaustive retrieval. In the experiment using an image database consisting of about 2,400 real images, it shows that the proposed method is about 18 times faster than 7he exhaustive method with almost same precision and it can retrieve more similar images which belong to the same class with a query image.

• Journal of Environmental Science International
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• v.25 no.1
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• pp.147-153
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• 2016

To investigate the impact of the number of runners developed from daughter plants during seedling on sapling growth and development during phase of first cluster, we examined four treatment groups that had 3-4, 5-6, 7-8, and 9-10 runners. As of June $5^{th}$, the group with 9-10 runners showed the highest number of saplings with more than 2 leaves, followed by groups with 7-8, 5-6, and 3-4 runners. Although observation on June $25^{th}$ and July $15^{th}$ showed a similar tendency for sapling numbers, no significant difference was detected between groups with 7-8 and 9-10 runners. The length of runners in the treated groups was similar to that in groups with 3-4 and 5-6 runners, with lengths of 49.4 mm and 48.0 mm, respectively, but runner length was significantly shorter in the group with 7-8 runners. Both the thickness and the weight of runners were highest in the group with 3-4 runners. The growth and development of daughter plants and root weight were similar between the groups with 3-4 and 5-6 runners, whereas both values were lower in groups with 7-8 and 9-10 runners. While stem crown thickness values were 8-7 mm and 8.5 mm in groups with 3-4 and 5-6 runners, respectively, groups with 7-8 and 9-10 runners had thinner stems of 7.1 mm and 6.2 mm, respectively. The fresh weight of saplings decreased as the number of runners increased. From the phase first cluster, leaf area and fresh weight were remarkably low in groups with 7-8 and 9-10 runners. Taken together, these results can be used to increase the production of high-quality saplings by providing a foundation for studies to investigate the impact of the number of runners developed from daughter plants on growth and development during the seedling period and the phase first cluster.

• Journal of the Korean Society of Clothing and Textiles
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• v.10 no.3
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• pp.37-48
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• 1986

The purpose of this study was to analyze 'the natural groupings' of subjects in order to classify highly similar somatotype for clothing construction. The sample for the study was drawn randomly out of senior high school boys in Seoul urban area. The sample size was 425 boys between age 16 and 18. Cluster analysis was more concerned with finding the hierarchical structure of subjects by three dimensional distance of stature. bust girth and sleeve length. The groups forming a partition can be subdivided into 5 and 6 sets by the hierarchical tree of the given subjects. Ward's Minimum Variance Method was applied after extraction of distance matrix by the Standardized Euclidean Distance. All of the above data was analyzed by the computer installed at Korea Advanced Institute of Science and Technology. The major findings, take for instance, of 16 age group can be summarized as follows. The results of cluster analysis of this study: 1. Cluster 1 (32 persons means $18.29\%$ of the total) is characterized with smaller bust girth than that of cluster 5, but stature and sleeve length of the cluster 1 are the largest group. 2. Cluster 2 (18 Persons means $10.29\%$ of the total) is characterized with the group of the smallest stature and sleeve length, but bust girth larger than that of cluster 3. 3. Cluster 3(35persons means $20\%$ of the total) is classified with the smallest group of all the stature, bust girth and sleeve length. 4. Cluster 4(60 persons means $34.29\%$ of the total) is grouped with the same value of sleeve length with the mean value of 16 age group, but the stature and bust girth is smaller than the mean value of this age group. 5. Cluster 5(30 persons means $17.14\%$ of the total) is characterized with smaller stature than that of cluster 1, and with larger bust girth than that of cluster 1, but with the same value of the sleeve length with the mean value of the 16 age group.

• Journal of The Korean Astronomical Society
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• v.28 no.1
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• pp.45-59
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• 1995

In the best observed Pleiades cluster, the luminosity function(LF) and mass function(MF) for main sequence(MS) stars extended to $Mv{\approx}15.5(V{\approx}21)$ are very similar to the initial luminosity function(ILF) and initial mass function(IMF) for field stars in the solar neighborhood showing a bump at log $m{\simeq}-0.05$ and a dip at log $m{\simeq}-0.12$. This dip is equivalent to the Wielen dip appearing in the LF for the field stars. The occurence of these bump and dip is independent of adopted mass-luminosity relation(MLR) . and their characteristics could be explained by a time-dependent bimodal IMF. The model with this IMF gives a total cluster mass of $\~700M_\bigodot,\;\~25$ brown dwarfs and $\~3$ white dwarfs if the upper mass limit of progenitor of white dwarf is greater than $4.5M_\bigodot$. The cluster age on the basis of LF for brightest stars is given by $\~8\times10^7yr$ and all stars in the cluster lie along the single age sequence in the C-M diagram without showing a large dispersion from the sequence.

• Interdisciplinary Bio Central
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• v.3 no.1
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• pp.4.1-4.7
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• 2011

Forty-seven wild accessions of Lotus japonicus Regal (Japanese trefoil) indigenous to Japan were investigated for nine morphological characters. Average temperature and annual precipitation were negatively correlated with stem color and seed weight. On the other hand, latitude was positively correlated with these traits. Consequently, accessions from sites at higher latitudes with low temperatures and precipitation tend to have dark red stems and heavy seeds. Cluster analysis based on nine morphological characters classified 47 wild accessions into six major groups. Cluster I included four accessions of tall and erect plants. These plants are phenotypically similar to commercial variety 'Empire'. Cluster II consisted of three accessions of creep plants with pale red stems. Cluster III contained 24 accessions that had average values for all morphological characters evaluated. Cluster IV included two accessions of erect plants with rounded leaflets and dark red stems. Cluster V included four accessions of small, creep plants with pale red stems. Cluster VI included seven accessions of small and erect plants, a phenotype that also applies to ?Gifu B-129?, which is used as experimental strain worldwide. These data were deposited into LegumeBase, an online database (http://www.legumebase.brc.miyazaki-u.ac.jp/) supported by the National BioResource Project (NBRP) in Japan.