• Journal of Forest and Environmental Science
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• v.37 no.3
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• pp.206-216
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• 2021

Deutzia paniculata Nakai, a rare and endemic plant, has limited distribution throughout the North and South Gyeongsang provinces of South Korea. The D. paniculata community grows mostly on the stony slopes of forests, valley edges, and rock layers at 250-960 m in altitude, where deciduous trees are dominant and high humidity is maintained. Correlation analysis of vegetation and environmental factors found that the Walter's dogwood-mulberry community was correlated with soil acidity (pH). Whilst the queritron community had correlations with distance from the valley, rock rate and slope. The natural habitat of the Palgongsan Mountain in Daegu is known to have high genetic diversity, had eight D. paniculata individuals recorded from 2014 to 2018, and 12 individuals recorded in 2020 (new individuals due to a newly created space within the herbaceous layer caused by grass mowing works), it is therefore unlikely that the community would perish unless there was an artificial disturbance. To conserve the natural habitats of D. paniculata, oppression by Sasa borealis, damage, increase in crown density of the upper layer, overexploitation, and absence of seedlings should be carefully investigated. In addition, response measures should also be established and the impact on seed fullness and the reproductive characteristics of D. paniculata recorded. To restore declined genetic diversity, individuals from high genetic diversity regions, such as Palgongsan Mountain, should be artificially transplanted.

• Journal of Digital Convergence
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• v.17 no.6
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• pp.27-33
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• 2019

The purpose of this study was to explore the moderating effect of learning strategy levels on the relationship between academic grit and career development competence perceived by high school students. The sample for this study comprised 573 high school students, and data analysis was conducted mainly using reliability analysis, correlation analysis, K-mean cluster analysis, hierarchical regression analysis. The results of the study showed that the learning strategy levels moderated the relationship between academic grit and career development competence. This study suggest it is necessary to provide grit enhancement programs coupled with learning strategy levels in order to facilitate career development competence. The future studies need to explore the literature review for logical relationship between academic grit and career development competence, the qualitative approach for drawing on the theoretical models among the related variables, and the relational research to explore mediating or moderating effect of the individual backgrounds and related variables on the relationship between academic grit and career development competence.

• Journal of Climate Change Research
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• v.7 no.3
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• pp.269-282
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• 2016

Watershed area can be submerged due to constructions and management of dams, and these change can impact not only on ecosystem and environment of river basin area but also on local climate. This study is conducted to construct and classify climate zones of Andong Dam watershed where the area is submerged due to the construction of the dam. By applying Principal Components Analysis (PCA) and Getis-Ord $Gi^*$ statistics, three climate zones were classified for the result. Each zone was then analyzed and validated with climatic and geological features including topography, land cover, and forest type map. As a result of the analysis, there was a difference in temperature, elevation, precipitation and tree species distribution among the zones. Also, an analysis of land cover map showed that there were more agricultural land near Andong Reservoir. This study on the climatic classification is considered to be useful as the basis for decision-making or policy enforcement regarding ecosystem, environmental management or climate change response.

• Journal of Digital Convergence
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• v.19 no.1
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• pp.361-371
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• 2021

Communication education research has focused on the effects of instructor characteristics on learning. It is necessary to consider student characteristics as well to develop an effective teaching strategy. The current study tries to classify students into multiple distinct groups depending on their personality traits and communication characteristics and investigates differences in effects of teacher characteristics between those groups. A survey on unversity students was conducted to collect data. A cluster analysis was carried out to identify distint sub-groups of respondents by their personality traits and communication characteristics. The analysis yielded two distinct groups. The two groups were named stable-reticent group', and 'neurotic-talkative group' respectivley. Series of multiple regression were carried out in order to investigate differences in the effects of instructor characteristics. The analyses found different patterns of effects between the two sub-groups. The findings suggest that it is necessary to adopt different communication styles and teaching strategies depending on student types.

• 한국노년학
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• v.32 no.3
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• pp.675-687
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• 2012

This study is aimed to investigate the difference of leisure time use of elderly groups clustered with demographic factors and finally produce the leisure profile. A total 5392 time diaries, filled up by 65-years old and over in 2009 Time Use Survey, were analyzed by using descriptive statistics, correlation, cluster analysis, and ANOVA accompanied with the Scheffe's tests. The subjects could be clustered into 7 groups such as still working, work than leisure, hobby with friends, various leisure in a city, with religion and friendship, working and doing leisure in their spare time, and leisure in suburb based upon demographic factors such as age, gender, spouse, education, job, income and living area. The data also revealed that the clusters had different time use patterns in pursuing leisure. Overall, leisure in later life could be influenced by working status, and play an important role in filling their loss of job or spouse. The findings could help us plan upcoming leisure program and policies for the elderly.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.4
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• pp.119-135
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• 2022

Digital platforms play crucial roles in terms of enabling and sustaining online communities. However, who really benefits from digital platform development, and what are the benefits digital platforms provide for the development of smart communities. This paper explores this question, the goal was to understand the links between digital platforms and smart communities, using the clustering methodology process to have a better understanding of characteristic of each digital platform, Twenty nine digital platforms is clustered and used as a study case. This paper explores how the categorization of digital platform characteristics encourages participation by a smart community, thus improving information and service delivery. On another side, the rise of digital platforms brings new challenges for policy maker to foster a smart community and firms the digital platform also offer benefits to giving effective and efficient service.

• Journal of Digital Convergence
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• v.20 no.2
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• pp.217-223
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• 2022

Subspace clustering for online data streams requires a large amount of memory resources as all subsets of data dimensions must be examined. In order to track the continuous change of clusters for a data stream in a finite memory space, in this paper, we propose a grid-based subspace clustering algorithm that effectively uses memory resources. Given an n-dimensional data stream, the distribution information of data items in data space is monitored by a grid-cell list. When the frequency of data items in the grid-cell list of the first level is high and it becomes a unit grid-cell, the grid-cell list of the next level is created as a child node in order to find clusters of all possible subspaces from the grid-cell. In this way, a maximum n-level grid-cell subspace tree is constructed, and a k-dimensional subspace cluster can be found at the k^th level of the subspace grid-cell tree. Through experiments, it was confirmed that the proposed method uses computing resources more efficiently by expanding only the dense space while maintaining the same accuracy as the existing method.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.6
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• pp.194-210
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• 2022

The user-centered EV charging infrastructure construction policy the government is aiming for can increase convenience for electric vehicle users and bring new electric vehicle users into the market. This study was conducted to provide an in-depth understanding of the charging behaviors of actual electric vehicle users, which can be used as basic information for the electric vehicle charging infrastructure. Based on charging diary data collected for a week, the charging of electric vehicles was analyzed on a daily and weekly basis, and sequence analysis and latent class analysis were used. As a result, five daily charging profiles and four weekly charging profiles were identified, which are expected to contribute to revitalizing the electric vehicle market by providing key information for decision-making by potential electric vehicle users as well for establishing user-centered charging infrastructure policies in the future.

• Journal of The Korean Association of Information Education
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• v.26 no.6
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• pp.553-566
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• 2022

This study collects social data and academic research data from portal sites and RISS, and analyzes TF-IDF, N-Gram, semantic network analysis, and CONCOR analysis to analyze the social awareness and current aspects of 'AI Literacy' and 'AI Convergence Education'. Through this, we tried to understand the social awareness aspect and the current situation, and to suggest implications and directions. In the social data, the collection of 'AI Convergence Education' was more than twice that of 'AI Literacy', indicating that awareness of 'AI Literacy' was relatively low. In 'AI Literacy', the keyword 'human' in social data showed no cluster to which it belonged, indicating a lack of philosophical interest in and awareness of humanities and AI. In addition, the keyword 'Ministry of Education' showed high frequency, importance, and centrality of connection only in the social data of 'AI convergence education', confirming that 'AI convergence education' is closely related to government policy.

• Korea Trade Review
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• v.43 no.4
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• pp.177-217
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• 2018

The purpose of this study is to classify the types of internationalization strategies utilized by Korean ventures and to examine whether there is a significant relationship between these types and internationalization performances. Specifically we tested whether there is a good feasibility through empirical analysis of the study model constructed through the following process. As a criterion of typification, the capability of international entrepreneurship and the capability of effectuation of a venture were chosen, and a model in which those three types exist based on the capabilities is established. The characteristics of each type and the contents of internationalization strategy are explained and empirical analysis is conducted. We also test whether there are significant differences in internationalization performance for each type. As a result of the cluster analysis, we concluded that there are three types : pioneer, careful preparation and passive response. In addition, these three types have significant differences in the levels of performances of reputation in foreign markets and the accumulation of knowledge in international management. This implies significant differences among the performances of each type of ventures according to their internationalization strategy positions. Therefore, the type of venture should be considered when a venture establishes its internationalization strategy and governments set supporting policy for venture companies.