• Phonetics and Speech Sciences
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• v.11 no.1
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• pp.29-40
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• 2019

The paper investigates the minimal pair of Korean phonemes quantitatively. To achieve this goal, I calculated the number of consonant minimal pairs in the syllable-initial position as both raw counts and relative counts, and analyzed the part of speech relations of the two words in the minimal pair. "Urimalsaem" was chosen as the object of this study because it was judged that the minimal pair analysis should be done through a dictionary and it is the largest among Korean dictionaries. The results of the study are summarized as follows. First, there were 153 types of minimal pairs out of 337,135 examples. The ranking of phoneme pairs from highest to lowest was 'ㅅ-ㅈ, ㄱ-ㅅ, ㄱ-ㅈ, ㄱ-ㅂ, ㄱ-ㅎ, ${\ldots}$, ㅆ-ㅋ, ㄸ-ㅋ, ㅉ-ㅋ, ㄹ-ㅃ, ㅃ-ㅋ'. The phonemes that played a major role in the formation of the minimal pair were /ㄱ, ㅅ, ㅈ, ㅂ, ㅊ/, in that order, which showed a high proportion of palatals. The correlation between the raw count of minimal pairs and the relative count of minimal pairs was found to be quite high r=0.937. Second, 87.91% of the minimal pairs shared the part of speech (same syntactic category). The most frequently observed type has been 'noun-noun' pair (70.25%), and 'vowel-vowel' pair (14.77%) was the next ranking. It can be indicated that the minimal pair could be grouped into similar categories in terms of semantics. The results of this study can be useful for various research in Korean linguistics, speech-language pathology, language education, language acquisition, speech synthesis, and artificial intelligence-machine learning as basic data related to Korean phonemes.

• Journal of Life Science
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• v.29 no.5
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• pp.555-563
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• 2019

This study was undertaken to investigate the effect of an ethanol extract of Elaeagnus umbellata leaves (EUL-EE) on skin-related biological activities. Previously, we have reported that gallic acid was the major phenolic compound in EUL-EE through quantitative analysis and that EUL-EE had an inhibitory effect against the proliferation of liver cancer HepG2 cells. In the present study, the inhibitory effects of EUL-EE on melanin production and tyrosinase activity in ${\alpha}$-melanocyte-stimulated hormone-stimulated B16-F0 cells were determined to assess the effects of EUL-EE on skin whitening. The anti-wrinkle effect using UVB-irradiated CCD-986sk cells was examined by the expression of type I procollagen and metalloproteinase (MMP)-1 release. The EUL-EE significantly decreased intracellular melanin production (33.0% inhibition at $100{\mu}g/ml$) when compared with untreated B16-F0 cells. Tyrosinase activities in the stimulated B16-F0 cells were also decreased by EUL-EE (47.8% inhibition at $100{\mu}g/ml$). The EUL-EE also dose-dependently increased the production of type I procollagen (up to 1.74-fold at $250{\mu}g/ml$) in CCD-986sk cells when compared with UVB-irradiated controls. EUL-EE showed no cytotoxicity at concentrations up to $500{\mu}g/ml$. In addition, EUL-EE at $10-500{\mu}g/ml$ inhibited the release of MMP-1 to the medium from UVB-irradiated CCD-986sk cells. Taken together, these observations indicate that EUL-EE has high potential for use as inner beauty and cosmetic materials due to its whitening and anti-wrinkle effects.

• Journal of Korea Water Resources Association
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• v.54 no.9
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• pp.731-745
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• 2021

In this study, the monthly temperature of the Han River basin was predicted by statistical multiple regression models that use global climate indices and weather data of the target region as predictors. The optimal predictors were selected through teleconnection analysis between the monthly temperature and the preceding patterns of each climate index, and forecast models capable of predicting up to 12 months in advance were constructed by combining the selected predictors and cross-validating the past period. Fore each target month, 1000 optimized models were derived and forecast ranges were presented. As a result of analyzing the predictability of monthly temperature from January 1992 to December 2020, PBIAS was -1.4 to -0.7%, RSR was 0.15 to 0.16, NSE was 0.98, and r was 0.99, indicating a high goodness-of-fit. The probability of each monthly observation being included in the forecast range was about 64.4% on average, and by month, the predictability was relatively high in September, December, February, and January, and low in April, August, and March. The predicted range and median were in good agreement with the observations, except for some periods when temperature was dramatically lower or higher than in normal years. The quantitative temperature forecast information derived from this study will be useful not only for forecasting changes in temperature in the future period (1 to 12 months in advance), but also in predicting changes in the hydro-ecological environment, including evapotranspiration highly correlated with temperature.

• Journal of Life Science
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• v.31 no.8
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• pp.710-718
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• 2021

Placenta-derived mesenchymal stem cells (PD-MSCs) are promising candidates for cell-based therapy in regenerative medicine. The migration and homing potential of PD-MSCs to injured sites is a critical property of MSC engraftment. MicroRNAs (miRNAs) have recently been shown to regulate the critical functions of MSCs, such as proliferation, survival, and migration. The objective of the present study was to identify the miRNA and target genes involved in PD-MSCs homing in a bile duct ligation (BDL) rat model. We selected candidate miRNAs targeting genes for PD-MSCs homing based on microarray analysis. PD-MSC engraftment in BDL-injured rat liver was identified by immunofluorescence assay and human-specific Alu gene expression by quantitative real-time polymerase chain reaction (qRT-PCR) one week after transplantation. Compared with migrated naïve PD-MSCs under hypoxic and normoxic conditions (Hyp/Nor), the transplanted group with PD-MSCs (Tx) showed distinct differences in miRNA expressions in BDL-injured rat liver. We also validated the miRNAs and their target genes for PD-MSCs homing. The expressions of integrin α4 (ITGA4) and integrin α5 (ITGA5) target genes for miR-199a-5p and miR-148a-3p were significantly upregulated in the Tx group (p<0.05). In addition, integrin β1 (ITGB1) and integrin β8 (ITGB8) were upregulated by suppressing miR-183-5p and miR-145-5p, respectively. These results demonstrated that PD-MSCs regulate miRNA expression related to the integrin family for their homing effects on the BDL-injured rat liver. The findings further suggest that miRNA-mediated regulation of the integrin family contributes to the therapeutic efficacy of PD-MSCs in the rat hepatic fibrosis model by BDL.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.2
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• pp.51-78
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• 2021

Followed by 'start-up', the theme of 'scale-up' has been considered as an important agenda in both corporate and policy spheres. In particular, although it is a term commonly used in industry and policy fields, even a conceptual definition has not been achieved from the academic perspective. "Corporate Growth" in the academic aspect and "Business Growth" in the practical management field have different understandings (Achtenhagen et al., 2010). Previous research on corporate growth has not departed from Penrose(1959)'s "Firm as a bundle of resources" and "the role of managers". Based on the theory and background of economics, existing research has mainly examined factors that contribute to firms' growth and their growth patterns. Comparatively, we lack knowledge on the firms' growth with a focus on 'annual revenue growth rate'. In the early stage of the firms, they tend to exhibit a high growth rate as it started with a lower level of annual revenue. However, when the firms reach annual revenue of more than 100 billion KRW, a threshold to be classified as a 'middle-standing enterprise' by Korean standards, they are unlikely to reach a high level of revenue growth rate. In our study, we used our sample of 333 companies (6.7% out of 5,000 'fastest-growing' companies) which reached 15% of the compound annual growth rate in the last three years with more than USD 100 million. It shows that sustaining 'high-growth' above a certain firm size is difficult. The study focuses on firms with annual revenue of more than $100 billion (approximately 120 billion KRW) from the 'Inc. 2020 fast-growing companies 5,000' list. The companies have been categorized into 1) Fast-growing companies (revenue CAGR 15%~40% between 2016 and 2019), 2) Hyper-growing companies (40%~99.9%), and 3) Super-growing (100% or more) with in-depth analysis of each group's characteristics. Also, the relationship between the revenue growth rate, individual company's strategy choice (market orientation, generic strategy, growth strategy, pioneer strategy), industry/market environment, and firm age is investigated with a quantitative approach. Through conducting the study, it aims to provide a reference to the 'Hyper-Growing Model' that combines the paths and factors of growth strategies. For policymakers, our study intends to provide a reference to which factors or environmental variables should be considered for 'optimal effective combinations' to promote firms' growth.

• Journal of Bio-Environment Control
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• v.30 no.1
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• pp.85-93
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• 2021

In hydroponic cultivation, in order to investigate the change of lettuce growth and physiologically active substances through CO2 tablet treatment in nutrient solution, we used a solid carbonated tablets commercially available in the Netherlands. The experiment consisted of 0.5-fold, 1-fold, and 2-fold treatment groups with no treatment as a control. As a result, the atmospheric CO2 concentration in the chamber after CO2 tablet treatment showed the highest value at 472.2 µL·L-1 in the 2-fold treatment zone immediately after treatment, and the pH in the nutrient solution decreased the most to pH 6.03 in the 2-fold treatment zone. After that, over time, the CO2 concentration and pH recovered to the level before treatment. Leaf width and leaf area of lettuce showed the highest values of 17.1cm and 1067.14 ㎠ when treated 2-fold with CO2 tablet, while fresh weight and dry weight of the above-ground part were highest at 63.87 g and 3.08 g in 0.5-fold treatment. The root length of lettuce was the longest (28.4 cm) in the control, but there was no significant difference in the fresh weight and the dry weight among the treatments. Apparently, it was observed that the root length of the lettuce was shortened by CO2 tablet treatment and a lot of side roots occurred. In addition, there was a growth disorder in which the roots turned black, but it was found that there was no negative effect on the growth of the above-ground part. As a result of analyzing the bioactive compounds of lettuce by CO2 tablet treatment, chlorogenic acid and quercetin were detected. As a result of quantitative analysis, chlorogenic acid increased by 249% compared to the control in 1-fold treatment, but quercetin decreased by 37%. As a result of comparing the DPPH radical scavenging ability showing antioxidant activity, the control and 0.5-fold treatment showed significantly higher values than the 1-fold and 2-fold treatments. This suggests that carbonated water treatment is effective in increasing the growth and bioactive compounds of hydroponic lettuce.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.3
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• pp.11-28
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• 2021

Due to its size and complex characteristics, it is not often to newly create a large park within an existing urban area. Also, there has been a lack of research on the planting design methodologies for a large park. This study aims to elucidate how ecological ideas can be applied to planting practice from a designer's perspective, and eventually suggest a planting design framework in the actual case, the Central Park in the City of Gwangju. This framework consists of spatial structure of planting area in order to connect and unite the separated green patches, to adapt to the changes of existing vegetation patterns, to maintain the visual continuity of landscape, and to organize the whole open space system. The framework can be provided for the spatial planning and planting design phase in which the landscape designer flexibly uses it with the design intentions as well as with an understanding of the physical, social, and aesthetic characteristics of the site. The significance of this approach is, first that it can maintain ecological and visual consistency of the both existing and introduced landscapes as a whole in spite of its intrinsic complexity and largeness, and second that it can help efficiently respond to the unexpected changes in the landscape. In the case study, comprehensive site analysis is conducted before developing the framework. In particular, wetlands and grasslands have been identified as potential wildlife habitat which critically determines the vegetation patterns of the green area. Accordingly, the lists of plant communities are presented along with the planting scheme for their shape, layout, and relations. The model of the plant community is developed responding to the structure of surrounding natural landscape. However, it is not designed to evolve to a specific plant community, but is rather a conceptual model of ecological potentials. Therefore, the application of the model has great flexibility by using other plant communities as an alternative as long as the characteristics of the communities are appropriate to the physical conditions. Even though this research provides valuable implications for landscape planning and design in the similar circumstances, there are several limitations to be overcome in the further research. First, there needs to be more sufficient field surveys on the wildlife habitats, which would help generate a more concrete planting model. Second, a landscape management plan should be included considering the condition of existing forest, in particular the afforested landscapes. Last, there is a lack of quantitative data for the models of some plant communities.

• Journal of Korea Water Resources Association
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• v.54 no.8
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• pp.629-641
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• 2021

In this study, a two-dimensional numerical model (Nays2DH) was applied to analyze the process of morphological changes in the river channel bed depending on the changes in the amount of flooding after fully opening the Sejong weir, which was constructed upstream of the Geum River. For this, numerical simulations were performed by assuming the flow conditions, such as a non-uniform flow (NF), unsteady flows (single flood event, SF), and a continuous flood event (CF). Here, in the cases of the SF and CF, the normalized hydrograph was calculated from real flood events, and then the hydrograph was reconfigured by the peak flow discharge according to the scenario, and then it was employed as the flow discharge at the upstream boundary condition. In this study, to quantitatively evaluate the morphological changes, we analyzed the time changes in the bed deformation the bed relief index (BRI), and we compared the aerial photographs of the study area and the numerical simulation results. As simulation results of the NF, when the steady flow discharge increases, the ratio of lower width to depth decreases and the speed of bar migration increases. The BRI initially increases, but the amount of change decreased with time. In addition, when the steady flow discharge increases, the BRI increased. In the case of SF, the speed of bar migration decreased with the change of the flow discharge. In terms of the morphological response to the peak flood discharge, the time lag also indicated. In other words, in the SF, the change of channel bed indicates a phase lag with respect to the hydraulic condition. In the result of numerical simulation of CF, the speed of bar migration depending on the peak flood discharges decreased exponentially despite the repeated flood occurrences. In addition, as in the result of SF, the phase lag indicated, and the speed of bar migration decreased exponentially. The BRI increased with time changes, but the rate of increase in the BRI was modest despite the continuous peak flooding. Through this study, the morphological changes based on the hydrological characteristics of the river were analyzed numerically, and the methodology suggested that a quantitative prediction for the river bed change according to the flow characteristic can be applied to the field.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.40 no.1
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• pp.74-80
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• 2022

The vegetation of historical sites has been a form of vegetation that has remained since some years ago, but in modern times, vegetation and terrain have been deformed or damaged due to urban development, which was followed by an industrialization. As a solution to this, it is necessary to establish a plan for restoration and management by referring to the vegetation and landscape remaining in the historic site as indicators. This study was conducted to provide basic data for vegetation and landscape management of Baekje Historic Sites in Seoul by comparing and analyzing location characteristics, existing vegetation, and remaining vegetation of past substitutional vegetation for Pungnaptoseong and Mongchontoseong, Baekje Historic Sites in Seoul. As a result of the study, Pungnaptoseong and Mongchontoseong are located near the main stream of the Han River, Pungnaptoseong is located on a flat land consisting of natural embankments and floodplains, and Mongchontoseong is located on a hilly area. In the case of existing vegetation, it has been confirmed that Pungnaptoseong mainly has ornamental trees planting sites, while Mongchontoseong has a distribution of residual species from the past that grow in villages and hilly lowlands. The Substitutional vegetation of Pungnaptoseong and Mongchontoseong was synthesized based on the location characteristics and actual vegetation, it is estimated that the hilly areas may have been divided into "Quercus aliena Blume.", "Quercus mongolica Fisch. ex Ledeb." and so on, "Pinus densiflora Siebold & Zucc." on dry land,"Salix koreensis Andersson.", "Juglans mandshurica Maxim.", "Alnus japonica (Thunb.) Steud." in rivers and tributaries, "Quercus acutissima Carruth." in the main part of the forest, "Pinus densiflora Siebold & Zucc.", "Salix koreensis Andersson.", "Zelkova serrata (Thunb.) Makino." as a divine tree in the beginning of the village. Since the 1960s, all substitutional vegetation in the past has disappeared due to the introduction of foreign species and the creation of urban areas in Pungnaptoseong and Mongchontoseong, and the landscape has also been damaged. Fortunately, the substitutional vegetation was estimated in consideration of the species of residual trees distributed along the walls, climate, location characteristics, and times, but this study was conducted based on literature and existing vegetation surveys. Therefore, it is necessary to supplement the past target vegetation in Baekje historical sites in Seoul through quantitative experiments such as plant relic analysis in the future.

• Journal of Christian Education in Korea
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• v.71
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• pp.181-210
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• 2022

The purpose of this study was to investigate the research trends related to the children's department of church schools. The purpose of this study is to present basic data for the study of the children's department of church schools by analyzing the research period, research contents, research methods, and subjects of research related to the children's department of church schools. For this study, 50 domestic master's and doctoral dissertations searched through the National Assembly Library and the Research Information Sharing Service(RISS) were extracted with the keywords of 'church school' and 'children's department'. The frequency and percentage were calculated by analyzing the research related to the children's department of the church school according to four criteria: research period, research content, research method, and research subject. As a result of the study, first, the research trend of research papers in the children's department of church schools was found to be 49 articles (98%) for master's degrees and 1 article (2%) for doctoral degrees from 1980 to 2022. Trends by research period are focused on master's degrees. Second, the trend by research content was 27 practical studies (54%) and 23 theory studies (46%). In the research related to the children's department of church schools, the practical research accounted for a relatively high percentage compared to the theory research. Third, the trends by research method were in the order of 30 literature studies (60%), 19 quantitative studies (38%), and 1 qualitative study (2%). Research related to children's departments in church schools is being actively conducted with a focus on literature research. Fourth, as for the trends by study subject, the study was conducted focusing on physical subjects, with 35 subjects (70%) and 15 subjects (30%) of personal subjects. As research is conducted from physical objects to church schools and media, it is necessary to study the connection between church schools and families. As the research on church school kindergarten is focused on adults (teachers, parents, and educational preachers), in-depth research on children in church schools and qualitative research with voices from the field of children's department in church schools are required.