• Journal of the Korean Society of Environmental Restoration Technology
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• v.27 no.2
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• pp.43-53
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• 2024

This study attempted to elucidate the ecological niches and influencing environmental factors of Quercus variabilis and Quercus acutissima, which are representative deciduous broad-leaved trees in Korean forests, taxonomically close and genetically similar, under climate change conditions. Under climate change conditions induced by increased CO₂ and temperature, soil moisture and nutrient environments were manipulated in four gradients. At the end of the growing, plants were harvested to measure growth responses, calculate ecological niches, and compare them with those of the control. Eperimental plants were grown for 180 days in a glass greenhouse designed with four gradients each for soil moisture and nutrient environments under climate change conditions induced by increased CO₂ and temperature. After harvesting, growth responses of leaf traits were measured, ecological niches were calculated, and these were compared with those of the control groups. Furthermore, the responses of the two species' populations were interpreted using principal component analysis(PCA) based on leaf trait measurements. As a result, under climate change conditions, the ecological niche breadth for moisture environment was broader for Quercus variabilis than Quercus acutissima, whereas for the nutrient environment, Quercus acutissima exhibited a broader niche breadth than Quercus variabilis. And the rate of change in ecological niche breadth due to climate change decreased for Quercus variabilis in both moisture and nutrient environments, while for Quercus acutissima, it increased in the moisture environment but decreased in the nutrient environment. Additionally, in terms of group responses, both Quercus variabilis and Quercus acutissima expanded their ecological niches under climate change conditions in both soil moisture and nutrient conditions, with Quercus acutissima exhibiting a broader niche than Quercus variabilis under nutrient conditions. These results indicate that the changes in leaf morphological characteristics and the responses of individuals reflecting them vary not only under climate change conditions but also depending on environmental factors.

• Journal of Wetlands Research
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• v.25 no.3
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• pp.205-212
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• 2023

This study was attempted to find out how the ecological niche and interspecies relationship of Quercus aliena and Q. serrata, which are the main constituents of potential natural vegetation along the riverside of mountains in Korea, under climate change conditions. To this end, soil moisture and soil nutrients were treated with 4 grad ients under climate change conditions with elevated CO₂ and temperature, plants we re harvested at the end of the growing season, growth responses of traits were measured, ecological niche breadth and overlap were calculated, and it was compared with that of the control group(ambient condition). In addition, the relationship between the two species was analyzed by principal component analysis using trait values. As a result, the ecological niche breadth of Q. aliena was wider than that of Q. serrata under the moisture environment conditions under climate change. Under nutrient conditions, the ecological niche of the two species were similar. In addition, the ecological overlap for soil moisture of Q. aliena and Q. serrata was wider than the soil nutrient gradient under climate change. The species with traits in which the increase in ecological niche breadth due to climate change occurred more than the decrease was Q. aliena in both water and nutrient gradients. And in the responses of the population level, due to climate change, the adaptability of Q. aliena was higher than that of Q. serrata under the soil moisture condition, but the two species were similar under the nutrient condition. These results mean that the competition between the two species occurs more severely in the water environment under climate change conditions, and at that time, Q. aliena has higher adaptability than Q. serrata.

• Journal of Research and Publication Ethics
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• v.3 no.2
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• pp.19-22
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• 2022

Purpose: The two (SCOPUS and SSCI) are the most reputed indexing databases in the world for social science area, and hence the most preferred by majority of researchers in filling the academia niche that may exist on any research topic This study aims to determine five key strategic tactics that the JIDB (Journal of Industrial Distribution & Business) can use to be indexed by SCOPUS and SSCI, following five main measures as discussed in main texts. Research design, data and methodology: The literature analysis which was selected by this study is appropriate to find out useful texts dataset and this analysis provides adequate evidence for previous literature collection. Results: From the current literature analysis, this study suggests five strategic tactics for JIDB to be a journal indexed in SCOPUS and SSCI. The five tactics are follows: (1) Understanding the Selection Process, (2) Content and Relevance, (3) Finding a Niche Technical Standards, (4) Clarity in Formatting and Structure, and (5) Citations and Publication Considerations. Conclusions: This study concludes that the five discussed tactics are all imperative in aiding the research and if JIDB follows all the select strategies, it will be bound to succeed for indexing in the two databases.

• Korean Journal of Environmental Biology
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• v.26 no.4
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• pp.385-391
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• 2008

In Korea, Quercus acutissima distributed in good condition with high nutrients and moisture content, but Quercus variabilis in dry soil or rock habitate. In order to understand this ecological distribution of Q. acutissima and Q. variabilis, we cultivated the seedlings of two oak species treated with light, soil moisture and nutrient gradients each four level, from May to October in glass house. Then we measured the ecological niche breadth and niche overlap of the two species, and analyzed the relationship of competition using cluster analysis and PCA ordination. Ecological niche breadths of Q. acutissima under moisture and nutrient treatments were slightly wider than those under light one. Among 14 characters measured, 6 characters related with length items were wider in all the environmental treatments, but 8 characters connected with weight terms narrower in light treatment. Ecological niche breadths of Q. variabilis under moisture and nutrient treatment were wider than those of light one. Ecological niche of Q. acutissima was wider than those of Q. variabilis in all the environmental treatments. Ecological overlap between two species was higher with a range of 0.87$\sim$0.92, especially higher in soil moisture factor. These results means that Q. acutissima is more competitive than Q. variabilis, especially in soil moisture condition. Two species were ordinated with distinct group based on 9 characters. From these results, it can be explained that what Q. variabilis distributed in bad soil condition is due to the escape strategy, because of its low competitive ability to Q. acutissima in natural communities.

• Journal of Korean Society of Forest Science
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• v.82 no.2
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• pp.176-187
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• 1993

Based on the analysis of ecomorphological characters for 84 tree and shrub species, climax indices were estimated so as to interpret the position of the successional sere for the species in the natural deciduous forest. Nineteen ecomorphological characters, considered to be associated with successional gradient in the forest, were selected for the study. One of 2 to 4 steps per character for each species was given on a standardized scale of increasing climaxness, and the index was computed by percent of the sum of the scoring values for total score. Calculated mean value of 54.2 for all indices. Carpinus laxiflora had the highest index value of 83.3, and Populus davidiana recorded the lowest of 18.8. The most climax group, greater than 70 of the index, contained only 9 species, intermediate group, between 40 to 70 of the index, had 58 species, and the most pioneer group, less than 40 of the index comprised 17 species. The result has noticed that the large number of species would take advantage of most diverse resource and niche in the intermediate stage of the sere in the forest. The three components, i.e., light absorption, reproduction, and wood quality were used as axes for a 3-dimensional projection of the relative position for 44 species by principal component analysis. Along the similar ecomorphological characters, four recognized species group were classified by cluster analysis. The distribution pattern of plant families on the index gradient showed that the Betulaceae and Aceraceae had the widest seral amplitude, and the Salicaceae was a family typified as pioneer. There were no families specializing entirely with climax niche.

• Journal of Internet Computing and Services
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• v.22 no.2
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• pp.89-107
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• 2021

This paper explores the empirically analyzes the competitive nature of the five social media by analyzing the proper SNS service such as Facebook, Instagram, YouTube, Pinterest, and Twitter. In this study, we surveyed the use and satisfaction of social media for SNS users by using the proper theory. A total of 224 users were selected for analysis. Based on the results of the questionnaire, factor analysis was carried out to extract common factors such as relationship, sociality, convenience, daily life, and entertainment. As a result of the research using proper analysis, Facebook showed the widest narrowness in sociality (.627) and convenience (.636) in the first place, and YouTube showed the lowest in daily life (.670) and entertainment (.615) In the relationship (.520), the Instagram was the widest. In terms of five factors, Facebook and YouTube have the greatest overlap in relationship (1.826) and sociality (2.696), while Pinterest and Twitter are the most common in daily life (1.937) and entertainment (2.263) There is redundancy, and for convenience (2.583), YouTube and Twitter have the most redundancy. Facebook, Instagram, and YouTube have a competitive advantage over Pinterest in terms of relationships, sociality, convenience, routine, and entertainment, and are competitive across all factors except Facebook, Instagram, and YouTube Twitter It is possible to confirm that it is superior.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2876-2881
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• 2010

This paper attempts to find out implications based on the comparative analysis of overseas expansion model between the Korean insurance companies and the German one. There are three types of the strategies of the overseas-expansion-model of insurer, i.e. customer-oriented localized strategy, niche market-oriented strategy, and growing market-oriented strategy. From the review of related literatures and through an interview conducted by the insurance specialist, the findings are some differences between Korean and German insurance companies, when they go into foreign insurance markets. Th significant differences between Korean and German insurers are a customer oriented localized strategy and niche market oriented strategy. The Korean insurer shows a strength on the overseas-expansion-strategy, but the most clients of the Korean insurer on overseas markets are also Korean companies and Korean immigrants. The Korean legal expenses insurance market is yet in its embryonic stage, while the German legal expenses insurance company is pushing ahead with a strategy focused on localization and niche market on the legal expenses insurance product. In conclusion, like a case of the German legal expenses insurance company, the Korean insurer needs a customer oriented localized strategy as well as a niche market oriented strategy on the overseas insurance market.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5070-5077
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• 2014

Many countries in the world have protected their native plants and utilized them as industrial materials in each country. In this aspect, it is increasingly important to develop cosmetics materials using native plants in Korea. Cosmetic materials have been developed with niche plants, such as Campanula takesimana Nakai, Dianthus superbus, Aster spathulifolius in Ullengdo, in which a specific plant distribution by distinct climate and environment was present. Water and ethanol extractions were performed from the calluses of Campanula takesimana Nakai, Dianthus superbus, Aster spathulifolius. HPLC analysis revealed different compositions and functions of effective elements in each ethanol extract. For example, all types of ethanol extracts showed an ability to heal wounds. In particular, the expression of the inflammation-related gene, COX-2, was decreased in response to the ethanol extracts of Dianthus superbus. These results indicate that the ethanol extracts from niche plants' calluses in Ullengdo are natural and environmentally-friendly compounds, and can be used as medical supplies associated with anti-inflammation and wound healing.

• The Journal of Information Technology
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• v.4 no.2
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• pp.51-68
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• 2001

This study integrates personality trait theory to empirically Investigate the corporate strategy in Korean venture firms. This study predicts that type A/B, locus of control(internal/external), and risk-taking/avoiding will be positively associated with corporate strategy selection. Corporate strategy selection consists of aggressive entry strategy and defensive niche market strategy. Data obtained from a survey of 87 venture business firms is used to construct final variable measures and test the hypothesized relationships. The statistical result shows that type A, internal, and risk-taking CEOs positively associated with aggressive entry strategy, and type B, external, and risk-avoiding CEOs positively associated with defensive niche market strategy. Additional analysis(multiple regression model) to test relatively importance of independents is used.

• The Journal of the Korea Contents Association
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• v.11 no.8
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• pp.448-458
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• 2011

The availability of many smartphone applications and ubiquitous Wi-Fi technology has greatly spread the uses of smartphones. Particularly smartphones with the locative media services in tourism are booming because location-based technology such as GPS is well suit with tourism and tourists' needs. Smartphones also overcome the technological limit of traditional information media such as printed book, newspaper, etc. Based on the Niche Theory, the study examines the competitive relationships among information media that are used in tourism including smartphones, traditional paper publications, and computers. The paper also examines the niche of each medium based on the theory and finds which medium is more effective and preferred by people who utilize the services before and during their travel.