• 제목/요약/키워드: cluster analyses

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To Use Facebook for Good: Usage, Cyberbullying Involvement, and Perceived Social Support

  • Wong, Natalie;McBride, Catherine
    • Child Studies in Asia-Pacific Contexts
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    • 제6권2호
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    • pp.59-72
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    • 2016
  • We examined the relationship between the extent of Facebook usage and social well-being with consideration of cyberbullying involvement using a person-oriented approach. Survey data were collected from a sample of 312 secondary students from Grades 7 and 8 in Hong Kong. Levels of cyberbullying involvement, Facebook usage and perceived social support were investigated. Participants were classified into three clusters based on the different levels of Facebook usage and cyberbullying victimization through cluster analyses (i.e., frequent Facebook user/noncyberbullied victim, frequent Facebook user/cyberbullied victim, and uninvolved). Our results showed that frequent Facebook users who are cyberbullied tend to engage in cyberbullying perpetration significantly more than the frequent Facebook users who are not cyberbullied, even when the latter reported higher Facebook usage. This result provides some support for the idea that cyberbullying victimization has additional value on top of the level of usage in explaining one's participation in cyberbullying perpetration. As expected, frequent Facebook users who were not cyberbullied reported the highest perceived social support among the three groups. What is even more interesting is the equal level of perceived social support found between the cyberbullied victims and the uninvolved. Our results suggest that, although limiting adolescents' Internet use might reduce their risks of being involved in cyberbullying, it might also take away the potential benefits they could get from interacting with the online community. Benefits of using the person-oriented approach in the study of cyberbullying are discussed.

식생활 라이프스타일 유형에 따른 다이어트 관련 태도와 인구 통계학적 특성의 차이분석: 20, 30대 성인을 중심으로 (Differences in Diet-Related Attitudes and Demographics by Type of Food-Lifestyle: Focused on Adults in Their 20s and 30s)

  • 박광희
    • Human Ecology Research
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    • 제53권6호
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    • pp.655-665
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    • 2015
  • This study classified respondents by food-lifestyle and investigated differences in diet-related attitudes and demographic variables among food-lifestyle groups. Diet-related attitudes consisted of variables such as interest in diet, trial number of diet, diet period, weight loss, diet motivation, verification of products approved by the Ministry of Food and Drug Safety, verification of manufacturer's reliability, examination of damage cases and side effects, and awareness of consumer protection law. This study administered a questionnaire survey to adults between the ages of 20 and 39 who lived in Daegu and Uijeongbu from November 17th to December 14th 2014. Data collected from 293 respondents were analyzed using descriptive statistics, factor analyses, cluster analysis, analysis of variance (ANOVA) and chi-square tests. Four clusters (passive eating habit group, active eating habit group, convenience oriented group, and taste and health oriented group) were developed according to four factors of food-lifestyle (health-conscious, popularity-seeking, taste-seeking, convenience-seeking). The results of the ANOVA and chi-square tests indicated significant differences in interest in diet, awareness of consumer protection law, verification of products approved by the Ministry of Food and Drug Safety, verification of manufacturer's reliability, examination of damage cases and side effects, gender, education levels and household monthly income levels among food-lifestyle groups.

중학생의 성별과 양성평등의식 유형에 따른 기술·가정교과에 대한 태도 차이 (Influence of Middle School Students' Gender Type and Gender Equity Awareness on Attitudes toward Technology and Home Economics)

  • 김은정;이윤정
    • Human Ecology Research
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    • 제56권1호
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    • pp.1-14
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    • 2018
  • Technology and Home Economics are associated with gender-related roles. In this respect, students' attitude toward these subjects may be influenced by gender equity awareness with attitudes that may perpetuate gender-biased images of subjects. This study examined the influence of gender equity awareness of middle school students on attitudes toward Technology and Home Economics. Data were collected through a survey to 442 students from eight purposively sampled middle schools in Seoul. Three gender equity awareness groups were identified through a cluster analysis: Equity in house work group (n=163), Traditional gender role group (n=102), and Equity in all areas group (n=152). The analyses of variances enabled an examination of the effects of gender and gender equity awareness. Differences were found among gender and gender equity awareness groups on attitudes toward Home Economics, but not toward Technology. Girls showed higher preference, higher perceived usefulness than boys, but with a lower importance for career preparation for Home Economics. Traditional gender role group scored the lowest on usefulness and importance for everyday life, yet highest on importance for career preparation. Equity in all areas group perceived lowest importance of Home Economics for career preparation. The results show that Home Economics is more strongly gender-typed than Technology, and that effort is needed to change the gender-biased image of the subject.

Photocatalytic Oxidation for Organic Dye using Phenol Resin-based Carbon-titania Composites

  • Oh, Won-Chun;Na, Yu-Ri
    • 한국세라믹학회지
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    • 제45권1호
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    • pp.36-42
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    • 2008
  • Carbon/$TiO_2$ composite photocatalysts were thermally synthesized with different mixing ratios of anatase to phenol resin through an ethanol solvent dissolving method. The XRD patterns revealed that only anatase phase can be identified for Carbon/$TiO_2$ composites. The diffraction peaks of carbon were not observed, however, due to the low carbon content on the $TiO_2$ surfaces and the low crystallinity of amorphous carbon. The results of chemical elemental analyses of the Carbon/$TiO_2$ composites showed that most of the spectra for these samples gave stronger peaks for carbon and Ti metal than that of any other elements. The BET surface area increases to the maximum value of $488\;m^2/g$ with the area depending on the amount of phenol resin. From the SEM images, small $TiO_2$ particles were homogeneously distributed to a composite cluster with the porosity of phenol resin-based carbon. From the photocatalytic results, the MB degradation should be attributed to the three kinds of synergetic effects, such as photocatalysis, adsorptivity, and electron transfer by light absorption between supporter $TiO_2$ and carbon.

주제공원의 경쟁력 제고 방안에 관한 연구: Hybrid Conjoint Analysis의 적용 (Application of Hybrid Conjoint Analysis to Improve Competitive Power of Theme Parks in Seoul and Its Suburbs)

  • 홍성권
    • 한국조경학회지
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    • 제23권2호
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    • pp.1-16
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    • 1995
  • This study was carried out to suggest method which can be used to improve competitive power of theme parks. The characteristics of Hybrid Conjoint Analysis were described and its usefulness for identification of specific types of service theme parks have to provide was tested "Lotte World, " "Seoul land," and "farmland" were selected as study areas, and .7 attributes with 3 levels were utilized for analyses. Master design with 81 profiles was constructed to meet the requirement of ′Compromise Plan 1,′and data was collected by in-personal interviews on the study areas. Respondents were grouped by cluster analysis, and their characteristics were analyzed by discriminant analysis. Then, part-worth of each attribute . was estimated by stagewise estimation model Calibrated model of each group did not show part-worths of attributes clearly because both main effects and 2-way interaction effects were included in the models. Therefore, calibrated models′ coefficients were used to calculate utilities of all possible combinations of attributes levels. The results showed that managers of theme parks have several options for providing a new service: the combination of attribute levels with the highest utility is they however, they can choose the other combinations with next highest utlities is they can not afford it. Several suggestions were described to cope with the problems when Hybrid Conjoint Analysis is applied to landscape architectural study.

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새만금호 안팎의 식물플랑크톤 군집과 식물수문적 수역특성 (Phytoplankton Community and Phytohydrographic Characteristics of the Inside and Outside of Saemangeum Reservoir)

  • 여환구
    • 한국산학기술학회논문지
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    • 제10권8호
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    • pp.2021-2025
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    • 2009
  • 새만금 방조제 물막이 공사 마무리 직후인 2006년 5월부터 11월까지 4회의 조사를 통해 방조제 안팎의 식물플랑크톤 군집구조에 의한 식물수문적 수역특성을 연구하였다. 집괴분석 결과 육수역과 해수역으로 크게 양분되는 모습을 보여주었고 조사시기별로 조사정점간의 유사도는 다소간의 변동이 지속되었다. 특히 여름철에는 같은 해수역임에도 불구하고 방조제를 경계로 내부수역 및 외부수역으로 확연히 구분되는 식물수문적 수역 분리를 보여주었다. 물막이 공사 후 새만금호는 염분이 감소하고 수질환경이 변화되어 식물플랑크톤의 군집조성에 의한 식물수문특성이 시기별로 변화가 지속되는 것으로 보인다.

Intraspecific Molecular Phylogeny, Genetic Variation and Phylogeography of Reticulitermes speratus (Isoptera:Rhinotermitidae)

  • Park, Yung Chul;Kitade, Osamu;Schwarz, Michael;Kim, Joo Pil;Kim, Won
    • Molecules and Cells
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    • 제21권1호
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    • pp.89-103
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    • 2006
  • Population structure was investigated in Reticulitermes speratus populations in the Korean Peninsula and the Japanese Archipelago. All trees derived from analyses of the combined sequence dataset of two mitochondrial genes, COII and COIII, showed that R. speratus populations cluster into two major clades comprising the Korean/southern Japanese populations and the northern Japanese populations. Analysis of population genetic structure showed strong genetic partitioning between populations of the two clades. To understand historical migration routes and current distributions, the phylogeographic history of R. speratus was inferred from intra-/interspecific phylogeny and divergence times estimated between the clades of the phylogenetic tree. The estimated migration route and divergence time of ancestral R. speratus are congruent with recent paleogeographic hypotheses involving land-bridge connections between the Asian continent and the Japanese Archipelago. We suggest that ancestral R. speratus separated into northern and southern Japanese populations after its migration into the Japanese main islands from East China during the early Pleistocene via the East China Sea basin, which may have been exposed during that period. The Korean populations seem to have diverged recently from southern Japanese populations; this may explain the current distribution of R. speratus in the Japanese Arachipelago, and account for why it is restricted to northern areas of the Tokara Strait.

A Study on the Sulfur-Resistant Catalysts for Water Gas Shift Reaction IV. Modification of $CoMo/γ-Al_2O_3$ Catalyst with K

  • 박진남;김재현;이호인
    • Bulletin of the Korean Chemical Society
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    • 제21권12호
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    • pp.1239-1244
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    • 2000
  • A study of K addition to the catalyst of CoMo/ ${\gamma}-Al_2O_3$ was studied. The catalyst with 10 at% of K to Mo atoms in 3C10M, the catalyst added 3 wt% CoO to 10 wt% $MoO_3/{\gamma}-Al_2O_3$, showed the highest activity for water gas shift reaction. The addition of K retarded the reducibility of cobalt-molybdenum catalysts. It gave, however, good dispersion and large BET surface area to the catalysts which were attributed to the disappearance of polymolybdate clustyer such as $Mo_7O_{24}^{6-}$ and the formation of small Mo$O_4^{2-}$ cluster. It was confirmed by the analyses of pore size distribution, activation energy, Raman spectroscopy, and electron diffraction. The activation energies and the frequency factors of the catalysts 3C10M and 5KC10M (the catalyst added 5 at% K for Mo to the catalyst 3C10M) were 43.1 and 47.8 kJ/mole, and 4,297 and 13,505 $sec^{-1}$, respectively. These values were also well correlated with our suggestion. These phenomena were attributed to the direct interaction between K and CoMo oxides irrelevant to the support.

키워드 네트워크 분석을 통한 "한국의학교육"과 "의학교육논단"의 연구동향 분석 (Analysis of Research Trends in the Korean Journal of Medical Education and Korean Medical Education Review Using Keyword Network Analysis)

  • 이애화;김순구;황일선
    • 의학교육논단
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    • 제23권3호
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    • pp.176-184
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    • 2021
  • The aim of this study was to analyze the research trends in articles published in the Korean Journal of Medical Education (KJME) and Korean Medical Education Review (KMER) using keyword network analysis. The analyses included 507 papers from 2010 to 2019 published in KJME and KMER. First, keyword frequency analysis showed that the research topics that appeared in both journals were "medical student," "curriculum," "clinical clerkship," and "undergraduate medical education." Second, centrality analysis of a network map of the keywords identified "curriculum" and "medical student" as highly important research topics in both journals. Third, a cluster analysis of 20 core keywords in KMER identified research clusters related to academic motivation, achievement, educational measurement, medical competence, and clinical practice (centered on "learning," while in KJME, clusters were related to educational method and program evaluation, medical competence, and clinical practice (centered on "teaching"). In conclusion, future medical education research needs to expand to encompass other research areas, such as educational methods, student evaluations, the educational environment, student counseling, and curriculum.

Complete mitochondrial genome of freshwater goby Rhinogobius cliffordpopei (Perciformes, Gobiidae): genome characterization and phylogenetic analysis

  • Zhong, Liqiang;Wang, Minghua;Li, Daming;Tang, Shengkai;Zhang, Tongqing;Bian, Wenji;Chen, Xiaohui
    • Genes and Genomics
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    • 제40권11호
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    • pp.1137-1148
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    • 2018
  • Freshwater gobies Rhinogobius cliffordpopei and R. giurinus are invasive species with particular concern because they have become dominant and were fierce competitors in the invaded areas in Yunnan-Guizhou Plateau (southwest of China). Information about genetic characteristics of R. giurinus have been published, but there were still no relevant reports about R. cliffordpopei. In present study, the complete mitochondrial genome of R. cliffordpopei was determined, which was 16,511 bp in length with A+T content of 51.1%, consisting of 13 protein-coding genes, 22 tRNAs, 2 ribosomal RNAs, and a control region. The gene composition and the structural arrangement of the R. cliffordpopei complete mtDNA were identical to most of other teleosts. Phylogenetic analyses placed R. cliffordpopei in a well-supported monophyletic cluster with other Rhinogobius fish. But the phylogenetic relationship between genus Rhinogobius and Tridentiger remained to be resolved.