• Journal of The Korean Association For Science Education
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• v.42 no.6
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• pp.611-619
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• 2022

The purpose of this study is to explore the possibility of applying big data analysis to provide appropriate feedback to students using evaluation data in science education at a time when interest in educational data mining has recently increased in education. In this study, we use the evaluation data of 2,576 students who took 24 questions of the national assessment of educational achievement. And we use K-means cluster analysis as a method of unsupervised machine learning for clustering. As a result of clustering, students were divided into six clusters. The middle-ranking students are divided into various clusters when compared to upper or lower ranks. According to the results of the cluster analysis, the most important factor influencing clusterization is academic achievement, and each cluster shows different characteristics in terms of content domains, subject competencies, and affective characteristics. Learning motivation is important among the affective domains in the lower-ranking achievement cluster, and scientific inquiry and problem-solving competency, as well as scientific communication competency have a major influence in terms of subject competencies. In the content domain, achievement of motion and energy and matter are important factors to distinguish the characteristics of the cluster. As a result, we can provide students with customized feedback for learning based on the characteristics of each cluster. We discuss implications of these results for science education, such as the possibility of using this study results, balanced learning by content domains, enhancement of subject competency, and improvement of scientific attitude.

• Bulletin of the Korean Chemical Society
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• v.24 no.6
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• pp.712-716
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• 2003

The semi-diabatic potential energy surfaces (PESs) of the excited states of polyatomic molecules can be constructed for use in ab initio molecular dynamics (AIMD) studies by relying on the continuity of the electronic energy, oscillator strength, and spherical extent of an excited state along with first derivatives of these quantities as computed by using the equation-of-motion coupled-cluster (EOM-CC) method. The semidiabatic PESs of both the π → $π^*$ valence excited state and the 3s-type Rydberg state of ethylene are presented and discussed in this paper, in conjunction with some of the AIMD results we obtained for these states.

• Journal of the Korean Vacuum Society
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• v.10 no.2
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• pp.207-212
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• 2001

In this study, synthesis condition of $TiO_2$ thin films which have optimal dielectric characteristics using sol-gel method was determined. Thin films were fabricated using sol which have optimal characteristics and their permittivity was measured. In case of the amount of water for hydrolysis smaller than that for stoichiometry, sol formed clear sol which have normal chain structure. On the contrary, in case of the amount of water for hydrolysis larger than that for stoichiometry, sol formed suspended sol which have cluster structure. The permittivity of thin films increased exponentially around $^{\circ}C$.

• The Korean Journal of Ecology
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• v.7 no.3
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• pp.119-131
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• 1983

The cluster analysis on the distribution of epiphytic lichens on the north, south, east and west slope of Mt. Hanra was carried out by three methods, sum of square algorithm (SSA), prinicipal component analysis (PCA) and multidimensional scaling method(MDS). Analysis of concentration (AOC) was used for the comparison between the lichen communities of north and south slope. The lichen species was identified 35 species by Hale and Culberson technique. The classification of sites by SSA method was divided into two areas in four slopes, and that of species by SSA, PCA and MDS methods was classified into three clusters in east slope, four clusters in south and west slope, and there clusters in north slope. The comparison between north and south slope of the distribution of lichens indicates that loight elevation of north slope (NH; 1600m~1900m) was similar to that of relative low elevation of south slope (SL; 1000m~1300m). The genus lichen, Anaptychia, Parmelia, Lobaria and peltigera was found as the dominant genus in both slopes.

• Mass Spectrometry Letters
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• v.2 no.3
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• pp.73-75
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• 2011

In the collisionally-activated dissociation of the proton-bound cluster ions of DNA base guanine (G) and cytosine (C), $G{\bullet}{\bullet}H^+{\bullet}{\bullet}C$, the abundance of [$CH^+$] ions was found to be higher than that of [$GH^+$] despite the fact that G has a higher proton affinity than C. This unexpected observation seems to demonstrate another example that the simple kinetic method scheme does not work. We suggest that a kinetic factor or detailed dynamics governing the proton transfer and dissociation should be carefully considered in the applications of the kinetic method to the proton affinity measurements.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.8
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• pp.1033-1038
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• 2004

LOD scores related to marbling scores and permutation test have been applied for the purpose detecting quantitative trait loci (QTL) and we selected a considerable major locus BM4311. K-means clustering, for the major DNA marker mining of BM4311 microsatellite loci in Hanwoo chromosome 6, has been tried and five traits are divided by three cluster groups. Then, the three cluster groups are classified according to six DNA markers. Finally, bootstrap test method to calculate confidence intervals, using resampling method, has been adapted in order to find major DNA markers. It could be concluded that the major markers of BM4311 locus in Hanwoo chromosome 6 were DNA marker 100 and 95 bp.

• Journal of the Korean Magnetics Society
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• v.21 no.1
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• pp.1-4
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• 2011

We have studied magnetic structure and magnetic anisotropy energy of cubic transition metal mono-oxide cluster FeO and MnO using OpenMX method based on density functional method. The calculation results show that the antiferromagnetic spin arrangement has the lowest energy for FeO and MnO due to the superexchange interactions. The magnetic anisotropy is only found for antiferromagnetically ordered FeO cluster, since occupied electron of 3d down-spin level induces the spin-orbit couplings with <111> directed angular momentum.

• Journal of the Korean Data and Information Science Society
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• v.14 no.3
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• pp.535-543
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• 2003

Cluster analysis has been widely used in many applications, such as pattern analysis or recognition, data analysis, image processing, market research on on-line or off-line and so on. Clustering can identify dense and sparse regions among data attributes or object attributes. But it requires many hours to get clusters that we want, because clustering is more primitive, explorative and we make many data an object of cluster analysis. In this paper we propose a new method of clustering using sample based on grid. It is more fast than any traditional clustering method and maintains its accuracy.

• 한국데이터정보과학회:학술대회논문집
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• 2003.05a
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• pp.97-108
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• 2003

Cluster analysis has been widely used in many applications, such that pattern analysis or recognition, data analysis, image processing, market research on on-line or off-line and so on. Clustering can identify dense and sparse regions among data attributes or object attributes. But it requires many hours to get clusters that we want, because of clustering is more primitive, explorative and we make many data an object of cluster analysis. In this paper we propose a new method of clustering using sample based on grid. It is more fast than any traditional clustering method and maintains its accuracy. It reduces running time by using grid-based sample. And other clustering applications can be more effective by using this methods with its original methods.

• 한국데이터정보과학회:학술대회논문집
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• 2003.05a
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• pp.77-88
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• 2003

Cluster analysis has been widely used in many applications, such that data analysis, pattern recognition, image processing, etc. But clustering requires many hours to get clusters that we want, because it is more primitive, explorative and we make many data an object of cluster analysis. In this paper we propose a new clustering method, 'Clustering algorithm using a center of gravity for grid-based sample'. It is more fast than any traditional clustering method and maintains accuracy. It reduces running time by using grid-based sample and keeps accuracy by using representative point, a center of gravity.