• 한국대기환경학회지
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• 제24권3호
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• pp.300-309
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• 2008

Variations in PM10 concentration between 2000 and 2005 from 84 urban air monitoring stations operated by the government were analyzed. The K-means cluster analysis was attempted using annual average and the 99th percentile of daily averages as parameters. The results obtained by excluding Asian dust episode days were compared with those obtained by using all available data. In any cases, the cluster with the highest mean concentration was mostly composed of stations in Seoul and Gyeonggi. Annual average of the cluster with the highest mean concentration showed a distinct decreasing trend, but that excluding Asian dust episode days did not show such a trend. Without Asian dust episode days high concentrations of monthly averages in March and April were also not observed. The effect of Asian dust was more pronounced in the 99th percentile of daily averages. The 99th percentile of daily averages of the cluster with the highest mean concentration was the highest in June following downs in April and May.

• 한국과학교육학회지
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• 제33권3호
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• pp.679-693
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• 2013

The purpose of this study is to develop an inventory to classify task commitment types of science learning and to classify highschool students' task commitment types. Firstly, inventory questions were designed following the literature analysis on the task commitment components which involve self confidence, high goal setting, and focused attention. Prototype inventory underwent the content validity test, pilot test, and reliability test. Through these steps, final inventory was input to 462 high school students and underwent the factor analysis and cluster analysis. Factor analysis confirmed three components of task commitment as the three factors of inventory questions. In order to find how many clusters exist, factors of developed inventory became new variables. Each factor's factor mean was calculated and served as the new variable of the cluster analysis. Cluster analysis extracted five clusters as task commitment types. The 5 clusters were suggested by the agglomarative schedule and dendrogram gained from a hierarchical cluster analysis with the setting of the Ward algorithm and Squared Euclidean distance. Based on the factor mean score, traits of each cluster could be drawn out. Inventory developed by this study is expected to be used to identify student commitment types and assess the effectiveness of task commitment enhancement programs.

• 동아시아식생활학회지
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• 제26권5호
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• pp.400-406
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• 2016

This study used K-mean cluster analysis to evaluate the preference and satisfaction according to consumption behavior of naturally fermented bread products among customers residing in the Seoul area. Naturally fermented bread products were best recognized as "great nutrients for good health" ($3.91{\pm}0.87$). The preference for naturally fermented bread products was due to "good taste and flavor" ($3.39{\pm}0.95$), and customers with "intention to purchase" showed a mean of $3.21{\pm}0.94$. The overall satisfaction for naturally fermented bread products was $3.26{\pm}0.75$. Among the specific categories that contributed to this overall satisfaction, "quality" showed the highest satisfaction with $3.43{\pm}0.77$, whereas "price" ($2.77{\pm}0.76$) and "variety" ($2.77{\pm}0.75$) exhibited the lowest. Among the items to modify for naturally fermented bread products, "variety" was the most important item (21.8%), followed by "lower price" and "convenience of purchase" at 19.7% and 17.9%, respectively. In K-mean cluster analysis, customers who frequently visited the bakery and purchased naturally fermented bread products (cluster 1) expressed strong preference, satisfaction, and consumption behavior. Furthermore, these customers expressed high satisfaction in "quality", "convenience of purchase", and "variety" of naturally fermented bread products.

• 한국의류학회지
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• 제10권3호
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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 Periodontal and Implant Science
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• 제26권3호
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• pp.725-734
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• 1996

The present study has been performed to revise the forms of early-onset periodontitis(EOP) into the homogeneous phenotypic subsets by cluster analysis using sets of clinical parameters. Retrospective radiographic interproximal alveolar bone levels were measured from cemento-enamel junctions on patients who have previously been diagnosed as having one of EOP during last 5 years. Mean interproximal bone levels(BL) and mesial bone level(Ratio) of 1st molars relative to mean interproximal bone levels of adjacent teeth(lst and 2nd premolars and canines)were calculated on each patient. Using parameters BL and Ratio(BR group) or BL, Ratio and age(BRA group), cluster analysis was performed to revise EOP patients into homogeneous subsets. At least three or four cluster could be homogeneously formed both in BR or BRA groups with statistically significant differences in parameters used among clusters as evidenced by MANOVA test. It was shown that the greater the BL, the smaller the Ratio was. It was also evident that mean interproximal bone levels were lowest aroud 1st molars and/or incisors regardless of cluster types. The results has provided cluster-based studies for identifying laboratory markers responsible for the development of EOP subsets.

• 상하수도학회지
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• 제36권3호
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• pp.149-165
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• 2022

The water consumption data of individual consumers must be analyzed and forecast to establish an effective water demand management plan. A k-mean cluster model that can monitor water use characteristics based on hourly water consumption data measured using automated meter reading devices and demographic factors is developed in this study. In addition, the quantification model that can estimate the daily water consumption is developed. K-mean cluster analysis based on the four clusters shows that the average silhouette coefficient is 0.63, also the silhouette coefficients of each cluster exceed 0.60, thereby verifying the high reliability of the cluster analysis. Furthermore, the clusters are clearly classified based on water usage and water usage patterns. The correlation coefficients of four quantification models for estimating water consumption exceed 0.74, confirming that the models can accurately simulate the investigated demographic data. The statistical significance of the models is considered reasonable, hence, they are applicable to the actual field. Because the use of automated smart water meters has become increasingly popular in recent year, water consumption has been metered remotely in many areas. The proposed methodology and the results obtained in this study are expected to facilitate improvements in the usability of smart water meters in the future.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.203-204
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• 2007

This paper investigated the influence on partial discharge distribution of various defects at the model power cable joints interface using K-means clustering. As the result of analyzing discharge number distribution of ${\Phi}-n$ cluster, clusters shifted to $0^{\circ}\;and\;180^{\circ}$ with increasing applying voltage. It was confirmed that discharge quantity and euclidean distance between centroids were increased with applying voltage from the analyzing centroid distribution of ${\Phi}-q$ cluster. The degree of dispersion was increased with calculating standard deviation of ${\Phi}-q$ cluster centroid. The tendency both number of discharge and mean value of ${\Phi}-q$ cluster centroid were some different with defect types.

• 디지털융복합연구
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• 제19권12호
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• pp.557-565
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• 2021

본 연구는 청소년을 대상으로, 부모의 양육태도 유형에 따른 자아존중감과 그릿 정도의 차이를 파악하고자 시도되었다. 한국청소년정책연구원의 한국아동·청소년패널조사(Korea Children Youth Panel Survey: KCYPS) 자료 중 2018년도 조사에 참여한 중학교 1학년 2,438명의 자료를 분석하였다. 수집된 자료는 계층적 군집분석(Hierachical Cluster Analysis)과 비계층적 방법(k-mean cluster analysis)으로 분석하였다. 그 결과, 청소년이 지각한 부모의 양육태도 유형은 '소극적 애정 수용형', '적극적 애정 수용형', '독재적 비일관형', '애정부족 거부형' 4개 유형으로 분류되었다. 또한, 양육태도의 4개 군집별로 자아존중감과 그릿의 정도에 유의한 차이가 있었다. 자아존중감과 그릿 모두 '적극적 애정 수용형'인 군집 2에서 가장 높게 나타났다. 향후, 청소년의 자아존중감과 그릿을 향상시키기 위해 각 군집별로 차별화된 부모교육이 필요하며, 교육 프로그램 개발에 본 연구가 기초자료로 활용될 수 있을 것이다.

• 한국환경과학회지
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• 제15권12호
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• pp.1125-1139
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• 2006

The cluster analysis of diurnal precipitation patterns is performed by using daily precipitation of 59 stations in South Korea from 1973 to 1996 in four seasons of each year. Four seasons are shifted forward by 15 days compared to the general ones. Number of clusters are 15 in winter, 16 in spring and autumn, and 26 in summer, respectively. One of the classes is the totally dry day in each season, indicating that precipitation is never observed at any station. This is treated separately in this study. Distribution of the days among the clusters is rather uneven with rather low area-mean precipitation occurring most frequently. These 4 (seasons)$\times$2 (wet and dry days) classes represent more than the half (59 %) of all days of the year. On the other hand, even the smallest seasonal clusters show at least $5\sim9$ members in the 24 years (1973-1996) period of classification. The cluster analysis is directly performed for the major $5\sim8$ non-correlated coefficients of the diurnal precipitation patterns obtained by factor analysis In order to consider the spatial correlation. More specifically, hierarchical clustering based on Euclidean distance and Ward's method of agglomeration is applied. The relative variance explained by the clustering is as high as average (63%) with better capability in spring (66%) and winter (69 %), but lower than average in autumn (60%) and summer (59%). Through applying weighted relative variances, i.e. dividing the squared deviations by the cluster averages, we obtain even better values, i.e 78 % in average, compared to the same index without clustering. This means that the highest variance remains in the clusters with more precipitation. Besides all statistics necessary for the validation of the final classification, 4 cluster centers are mapped for each season to illustrate the range of typical extremities, paired according to their area mean precipitation or negative pattern correlation. Possible alternatives of the performed classification and reasons for their rejection are also discussed with inclusion of a wide spectrum of recommended applications.

• 한국지리정보학회지
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• 제23권3호
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• pp.68-84
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• 2020

본 연구에서는 경상남도 창원시를 대상으로 노인인구 분포지역의 공간적 특성과 폭염과의 관계를 분석하였다. 이를 위해 통계청의 인구센서스 자료와 환경부 토지피복도, Landsat 8 지표면온도, 기상청의 폭염일수 자료를 활용하였다. 노인인구 분포의 공간적 특성은 토지이용특성을 고려하여 K-mean 군집화 분석을 통해 총 5개 유형으로 분류하였다. 공간유형별 노인인구 특성은 도시화된 유형(cluster-3)에서 노인인구의 수가 많았으나, 농촌지역과 산림지역에 분포하는 유형(cluster-1, cluster-2)에서는 노인인구의 구성 비율이 높은 것으로 나타났다. 지표면온도와 폭염일수 특성에서는 도시지역에서 지표면온도가 가장 높았으나 폭염일수는 농촌지역이 가장 많았다. 노인인구 분포지역의 공간유형에 따른 폭염 특성을 분석한 결과, 농촌지역 면적이 많은 cluster-2가 15.95일로 가장 높았고, 도시화된 유형인 cluster-3은 9.41일로 가장 낮았다. 즉, 도시지역에 거주하는 노인인구보다 농촌지역에 거주하는 노인인구가 폭염에 더욱 노출되어 있으며, 피해가 가중될 것으로 예상된다. 본 연구의 결과는 여름철 폭염 취약지역의 효과적인 관리와 사전 예방을 위한 다양한 정책방안을 마련하는데 기초적인 자료로 활용될 수 있을 것이다.