• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.5
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• pp.122-130
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• 2008

Improving the transmission rates of multi-media delivery, such as moving pictures and internet services, has become increasingly important in modern society. To satisfy such high data rate requirements, the MIMO technique, which has the capacity to transmit large amounts of data using limited frequency resources, was developed. The Space Division Multiplexing (SDM) system is one of the MIMO techniques to be able to improve the transmission capacity. However, it is unable to achieve diversity gain because of interference due to the use of multiple antennas. In this paper, an SDM system that utilizes a Multi-Block method as an advanced transmission technique in a wireless communication system to obtain diversity gain is proposed and discussed fur the performance of the proposed system.

• Korean Journal of Ecology and Environment
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• v.53 no.1
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• pp.31-45
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• 2020

The biological indices based on the community structure with species richness and/or abundance are commonly used to assess aquatic ecosystem health. Meanwhile, recently functional traits-based approach is considered in ecosystem health assessment to reflect ecosystem functioning. In this study, we developed a database of biological traits for 136 taxa consisting of major stream insects (Ephemeroptera, Plecoptera, Trichoptera, Coleoptera, and Odonata) collected at Korean streams on the nationwide scale. In addition, we obtained environmental variables in five categories (geography, climate, land use, hydrology and physicochemistry) measured at each sampling site. We evaluated the relationships between community indices based on taxonomic diversity and functional diversity estimated from biological traits. We classified sampling sites based on similarities of their environmental variables and evaluated relations between clusters of sampling sites and diversity indices and biological traits. Our results showed that functional diversity was highly correlated with Shannon diversity index and species richness. The six clusters of sampling sites defined by a hierarchical cluster analysis reflected differences of their environmental variables. Samples in cluster 1 were mostly from high altitude areas, whereas samples in cluster 6 were from lowland areas. Non-metric multidimensional scaling (NMDS) displayed similar patterns with cluster analysis and presented variation of taxonomic diversity and functional diversity. Based on NMDS and community-weighted mean trait value matrix, species in clusters 1-3 displayed the resistance strategy in the life history strategy to the environmental variables whereas species in clusters 4-6 presented the resilience strategy. These results suggest that functional diversity can complement the biological monitoring assessment based on taxonomic diversity and can be used as biological monitoring assessment tool reflecting changes of ecosystem functioning responding to environmental changes.

• Journal of Environmental Science International
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• v.29 no.2
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• pp.145-154
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• 2020

The purpose of this study is to examine the differences of use behavior and environmental perception of a park and to analyze the influence of environmental perception factors on park satisfaction among 7 parks in Suseong-gu, Daegu. The data from the 255 questionnaires of young adults (30-59) and old adults (more than 60) who use the park more than once a week were used for the analysis. In terms of park use behavior, young adults used the park for walking and jogging mainly on weekday evenings, while old adults used the park for walking and rest mainly during weekday daytimes. In addition, old adults used the park more times a week than young adults, and spent more time in the park. In the analysis of the environmental perception of the park, similar results were found in both age groups but overall, old adults were more satisfied with the park environment than the young adults. As a result of analyzing the influence of environmental perception factors, it was determined that park satisfaction in young adults has a significant influence on 'use amenity', 'use convenience', 'facility suitability', and 'landscape diversity' in this order. On the other hand, park satisfaction for old adults has an influence on 'use amenity', 'facility suitability', and 'use convenience' in this order. The findings of this study can be used as an effective basic data for future park planning considering age groups.

• The Journal of the Korea Contents Association
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• v.20 no.6
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• pp.279-292
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• 2020

The purpose of this study is to suggest what the effect of channel brand equity is in the environment of multi-platform and to raise how channel brand equity is important by investigating how terrestrial TV's channel brand equity influences viewers' choice and use of the terrestrial TV contents on the multi-platform. The findings showed that the terrestrial TV's channel brand equity partially had a significant effect on the degree of use of Terrestrial TV contents on multi-platforms, but it did not on the diversity of media for viewing the terrestrial TV contents. In addition, it partially had an influence on the use of platform and service for viewing terrestrial TV contents by type. Finally, it also partially had impacts on the diversity of genre and the genre use by type. The findings suggest that the channel brand equity can have effects on the viewers' choice and use of broadcasting contents on the multi-platforms, and thus this study provides significant insights on what strategies are required for the competitiveness of broadcasting channels.

• Korean Journal of Childcare and Education
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• v.12 no.4
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• pp.41-69
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• 2016

The purpose of this study is to promote the use of cultural facilities of North Korean refugee mothers with young children by finding out their past experience of cultural facility use. The subjects of this study were 183 North Korean refugee mothers with young children and a total of four research participants. A survey and in-depth interviews were used to draw reliable research results. The research results are as follows: First, as to uses of cultural facilities, North Korean refugee mothers with young children got information about cultural facilities through the Internet community such as Internet cafes and blogs. Their considerations for using cultural facilities were diversity of activity programs and subdivision of performances and arts activities. Over 50% of mothers responded that cultural facilities were needed to enhance the creativity of their children. Second, concerning difficulties of cultural facility use, the most difficulty was high costs, and the second most difficulty was absence of cultural facilities nearby their residence. Third, as to the needs of cultural facility use, a children's library was needed the most for children's development. They responded that the most necessary policy for cultural facility use was to increase cultural vouchers for low-income households and to expand recipients of these vouchers.

• Knowledge Management Research
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• v.19 no.2
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• pp.163-185
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• 2018

In order to solve problems in an uncertain and complicated management environment of the modern world, a creative solution that combines diverse perspectives, knowledge, and effort based on diversity within an organization is required. Smart work environment provides an opportunity to express the potential diversity of an individual, extending the source of ideas to the organization, enhancing communication, and linking and sharing information and knowledge. So, this results in increased creative behavior. The purpose of this study is to investigate the effect of the process of connecting and sharing information and knowledge of organizational members on creative behavior and the effect of smart work environment in the process. The purpose of this study is to identify roles of job autonomy, self-efficacy, knowledge sharing and smart work environment in creative process. For the study, 353 surveys with work use group(156 people) and unused group(197 people). Statistical analysis included validity and reliability analysis, structural model analysis. The results showed that self-efficacy and job autonomy had positive effects on creative behavior and knowledge sharing, and job autonomy had a positive effect on self-efficacy. Knowledge sharing has a positive effect on creative behavior, and mediates the relationship between self-efficacy, job autonomy and creative behavior. Particularly, knowledge sharing has a more positive effect on smart work use group. In case of smart work use group, self-efficacy and job autonomy have a relatively high influence on knowledge sharing rather than direct influence on creative behavior appear. This result implies that the achievements of smart work are revealed in terms of knowledge sharing and creative behavior.

• Journal of Life Science
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• v.19 no.2
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• pp.169-173
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• 2009

To assist in selection schemes we estimate the genetic diversity of the horse breeds. Genetic diversity at 13 microsatellite loci was compared in six horse breeds : Jeju Native Horse, American Quarter, Jeju Racing Horse, Mongolian Horse, Japanese Horse and Thoroughbred. All of the equine microsatellite used in this study were amplified and were polymorphic. The expected total heterozygosity over all the populations varied between 0.669 and 0.869 and the expected heterozygosity within population range from 0.569 to 0.219 in this study. The low coefficient of gene differentiation value showed that only 0.118 of the diversity was between horses breeds. The constructed dendrogram from the genetic distance matrix showed little differentiation between horse breeds using DISPAN program. The genetic distance using 13 microsatellites ranged between 0.137 and 0.414 for the six horse breeds. These results confirm the potential use of equine microsatellite loci as a tool for genetic studies in horse populations. The genetic diversity of the six horse breeds to each other closed to their geographical distribution. Suggesting that the loci would be suitable for horse breeds parentage testing. Therefore, Microsatellite marker seems to be very useful for clarifying the evolutionary relationships of closely related populations.

• Korean Journal of Environment and Ecology
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• v.29 no.6
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• pp.907-916
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• 2015

The purpose of this study was to identify characteristics of vegetation structure, vegetation succession, and species diversity of artificially planted Chamaecyparis obtusa (CO) stands. The study was carried out by performing vegetation survey for eight CO stands located in Jeollanam-do Province, Korea. Analysis on vegetation classification and ordinations of the stands was conducted using the data from the vegetation survey, and as a result, the stands were classified into five types of communities. Community I showed a considerably lower index of species diversity when compared to other communities because the canopy of the dominant CO was so highly dense that the low-height vegetation was not able to develop or the low-height vegetation almost disappeared due to elimination of weed trees. Meanwhile, the Community II - IV had relatively higher indices of species diversity because various native tree species mixed with the low-height vegetation and competed with each other in the understory and shrub layers to some degree of stability or in their early stage of vegetation development. Community V, lastly, showed higher use intensity as a recreational forest, thus developing simpler vegetation structure on account of artificial intervention. There was positive correlation between photosynthetically active radiation entering the forest floor, number of observed species and index of species diversity. Such characteristics of vegetation structure in CO stands are closely associated with forest management and prescription for planting reforestation, thinning, and brush cutting in the past. There was a slight difference in vegetation structure and species diversity by communities, based on rotation time of the vegetational succession, process of disturbance frequency and disturbance, development, and maturity by planting CO stands. However, when compared to natural forests, the CO stands showed simpler vegetation structure. Because artificial forests are vulnerable in ecosystem service with lower species diversity, a drive for ecological management is needed for such forests to change into healthy ecosystems that can display functions of public benefit.

• Journal of the Economic Geographical Society of Korea
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• v.17 no.1
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• pp.129-146
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• 2014

This paper investigates how industrial diversity affects unemployment and employment instability from the perspective of the regional economy. Through this analysis, we examine how the industry-specific policy to promote some industry strategically in most of areas affects the stability of the regional economy. We measure Herfindahl indexes using the 1993-2010 data of 16 regions in Korea, and use panel regression model for empirical analysis. The main results from this empirical analysis are summarized as follows. First, we confirm that the industrial structure of most regions has been changed to the direction of specialization in 1990s and to the direction of diversification in 2000s through analyzing the changes in the values of Herfindahl indexes during the given period. Second, we find from the estimation results of panel regression model that the higher industrial diversity in most of regions is, the lower the unemployment rate is. However, a statistically significant relationship between industrial diversity and employment instability only partially confirmed. Third, there exist high unemployment rate and employment instability in most metropolitan areas, but it is hard to say that this relationship is highly statistically significant. From the results of the empirical analysis, it is likely that the industry-specific policies such as the regional strategic industry development policies unlike policy goals make the unemployment rate to rise and economic instability to increase. From the viewpoint of employment aspects, the strategies to increase industrial diversity would be desirable rather than those to specialize in the industrial structure.

• Journal of Intelligence and Information Systems
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• v.16 no.1
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• pp.93-116
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• 2010

Ensemble approach is applied to the detection modeling of illegal cash accommodation (ICA) that is the well-known type of fraudulent usages of credit cards in far east nations and has not been addressed in the academic literatures. The performance of fraud detection model (FDM) suffers from the imbalanced data problem, which can be remedied to some extent using an ensemble of many classifiers. It is generally accepted that ensembles of classifiers produce better accuracy than a single classifier provided there is diversity in the ensemble. Furthermore, recent researches reveal that it may be better to ensemble some selected classifiers instead of all of the classifiers at hand. For the effective detection of ICA, we adopt ensemble size reduction technique that prunes the ensemble of all classifiers using accuracy and diversity measures. The diversity in ensemble manifests itself as disagreement or ambiguity among members. Data imbalance intrinsic to FDM affects our approach for ICA detection in two ways. First, we suggest the training procedure with over-sampling methods to obtain diverse training data sets. Second, we use some variants of accuracy and diversity measures that focus on fraud class. We also dynamically calculate the diversity measure-Forward Addition and Backward Elimination. In our experiments, Neural Networks, Decision Trees and Logit Regressions are the base models as the ensemble members and the performance of homogeneous ensembles are compared with that of heterogeneous ensembles. The experimental results show that the reduced size ensemble is as accurate on average over the data-sets tested as the non-pruned version, which provides benefits in terms of its application efficiency and reduced complexity of the ensemble.