• Animal Systematics, Evolution and Diversity
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• v.11 no.1
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• pp.39-64
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• 1995

A faunistic and ecological study on the occurrence of freshwater cladocerans and copepods was accomplished from Chindo, South Korea. Collections were made from total 35 stations, comprising the various freshwater habitats like reservoirs, streams, swamps, bogs, ricefields, ditch, pond, and spring during the periods of July 23-25, and November 1-3 in 1994. Twenty seven cladoceran species of 17 genera of 6 families in 2 orders, and 28 copepod species of 21 genera of 6 families in 3 orders were collected during this research period, of which Daphnia obtusa Kurz and Elaphoidella bidens (Schmeil) are newly recorded from Korea. In reservoirs, Diaphanosoma sp. and Thermocyclops taihokuensis were dominant in July, and then succeeded by Bosmina longirostris and Cyclops vicinus vicinus in November. Thermocyclops crassus co-occurred with 7: taihokuensis at both seasons, was frequent in November after T. taihokuensis precipitately decreased. In other stagnant waters, 7: taihokuensis and Moina weismanni were dominant at ponds in July and in November, respectively. At ricefields in July Moina macrocopa and T. taihokuensis were dominant, but in November M. macrocopa and Paracyclops fimbriatus were. At streams, cladocerans were relatively rare, but became more rich in November. The representative cladoceran species were Bosmina longirostris as a plankton, and Chydorus sphaericus as a epibenthic species. Concerning copepods, nearly all the stations of streams except a few ones adjacent to seashore showed the similiar species constitutions, of which E. serrulatus and M, pehpeiensis were most frequent and abundant. At a mountain streamlet and a spring, the occurrence of Alona sp., Attheyella byblis Chang and Kim, 1992 and A. tetraspinosa Chang, 1993 is quite interesting and deserved much attention in the taxonomical point of view. Seventeen major cladocerans and copepods from lentic habitats and 13 major cladocerans and copepods from lotic habitatats were clustered using average taxonomic distance and UPGMA to infer the co-occurrence relations among species. As for lentic habitats, two large phena were appeared at first. The one phenon consisted of Diaphanosoma sp. and T taihokuensis, and showed its predominancy over the various habitats and its dominancy was rapidly decreased in November. The other phenon frequently occurred rather in November, and subdivided into three subgroups. On the other hand, as for lotic habitats, 13 species were also grouped into 2 large phena. The first one comprised 4 species, which were dominant and highly frequent at nearly all the lotic habitats, and subdivided into three subgroups according to their seasonal fluctuation types. The second one was also subdivided into three phena, the first of which comprised only one species, Microcyclops varicans, and occurred at most of the stations along stream with steadiness through the research period; the second phenon, Chydorus sphaericus, occurred much frequently in November; the last phenon included a few heterogenous subgroups.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.189-199
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• 2017

This study investigated the effects of life stress, cultural adaptation stress, and academic satisfaction amongst a total of 283 20's Chinese students majoring in cosmetology at colleges in Seoul. For this, data was collected from February to March 2017. The frequency analysis was conducted to verity the general characteristic of Chinese student studying in Korea who are study objects while utilizing SPSS Statistics V22.0 for data processing and analysis while the factor analysis and reliability analysis were conducted to investigate the validity of measurement tool and evaluate the reliability. Moreover, the regression analysis between variables and regression analysis were utilized. The results found the following: First, in terms of life stress, as peer relationship, appearance stress, economic stress, family relationship stress and academic stresses decreased, their academic satisfaction increased. Second, regarding cultural adaptation stress, as interpersonal and living culture stresses were lowered, academic satisfaction increased. Therefore, this study targets to derive implications on an efficient plan to improve the academic satisfaction of Chinese students studying in the Republic of Korea by developing and providing a proper academic program with a decent support system in terms of culture, life, and education after investigating their life and cultural adaptation stresses.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.3
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• pp.141-156
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• 2023

Due to the unprecedented worldwide pandemic of the new Covid-19 infection, business trends of companies have changed significantly. Therefore, it is strongly required to monitor the rapid changes of innovation trends to design and plan future businesses. Since the pandemic, many studies have attempted to analyze business changes, but they are limited to specific industries and are insufficient in terms of data objectivity. In response, this study aims to analyze business trends after Covid-19 using Crunchbase, a global startup data. The data is collected and preprocessed every two years from 2018 to 2021 to compare the business trends. To capture the major trends, a network analysis is conducted for the industry groups and industry information based on the co-occurrence. To analyze the minor trends, LDA-based topic modelling and word2vec-based clustering is used. As a result, e-commerce, education, delivery, game and entertainment industries are promising based on their technological advances, showing extension and diversification of industry boundaries as well as digitalization and servitization of business contents. This study is expected to help venture capitalists and entrepreneurs to understand the rapid changes under the impact of Covid-19 and to make right decisions for the future.

• Journal of Environmental Impact Assessment
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• v.32 no.3
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• pp.157-165
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• 2023

In Korea, a major contaminant of farmland soils in the vicinity of abandoned mines is arsenic, for which the general soil reclamation method is contaminated soil stabilization and cover the stabilized soil with clean soil at a thickness of 40 cm. In a previous pot experiment study we confirmed the feasibility of a lower thickness (20 cm) of covering soil for such reclamation in abandoned coal mines, where arsenic contamination levels are generally lower than in metal mines. In this subsequent study a field experiment including rice plant cultivation in field test plots was conducted. For over 4 months, the transfer of arsenic from the contaminated soil to the unpolished rice grains was reduced by 44% when a clean soil covering with a thickness of 20 cm was applied. The maximum decrease (56%) was shown when the stabilization process was performed before the covering. These results reveal a lower thickness of clean soil covering has a high feasibility and it can increase cost-efficiency in the reclamation of an abandoned coal mine.

• Applied Biological Chemistry
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• v.27 no.4
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• pp.278-284
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• 1984

The triglyceride compositions of peach kernel and apricot kernel oil have been investigated by a combination of high performance liquid chromatography (HPLC) and gas liquid chromatography(GLC). The triglycerides of peach kernel and apricot kernel oil were first separated by thin layer chromatography(TLC), and fractionated on the basis of their partition number(PN) by HPLC on a C-18 ${\mu}-Bondapak$ column with methanol-chloroform solvent mixture. Each of these fractionated groups was purely collected and analyzed by GLC according to acyl carbon number(CN) of triglyceride. Also the fatty acid compositions of these triglycerides were determined by GLC. From the consecutive analyses of these three chromatography techniques, the possible triglyceride compositions of peach kernel and apricot kernel oil were combinated into fifteen and thirteen kinds of triglycerides, respectively. The major triglycerides of peach ternel oil were those of $(3{\times}C_{18:1}\;30.9%)$, $(2{\times}C_{18:1},\;C_{18:2},\;21.2%)$, $(C_{18:1},\;2{\times}C_{18:2}\;10.6%)$, $(3{\times}C_{18:2}\;3.8%)$, $(C_{18:0},\;2{\times}C_{18:1},\;1.8%)$, $(C_{16:0},\;C_{18:1},\;C_{18:2},\;1.5%)$, $(C_{18:0},\;C_{18:1},\;C_{18:2},\;1.1%)$ and those of apricot kernel oil were $(3{\times}C_{18:1},\;39.5%)$, $(2{\times}C_{18:1},\;C_{18:2},\;24.5%)$, $(C_{18:0},\;2{\times}C_{18:2},\;14.2%)$, $(3{\times}C_{18:2},\;2.0%)$.

• Journal of Digital Convergence
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• v.19 no.4
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• pp.177-183
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• 2021

The purpose of this study was to investigate the double mediation effects of interpersonal relationship ability and self-efficacy in the link between family strengths and self-esteem of college students. To this end, a survey was conducted for 1 month in November 2019, targeting 340 students conveniently sampled from C city in Chungcheongbuk-do and J city in Jeollabuk-do, and the analysis was conducted using SPSS Win. 25 and SPSS PROCESS Macro. The applied statistical techniques were mean comparison analysis (t-test, One-ANOVA), correlation analysis, and PROCESS Macro model No. 6 to analyze the double mediating effect. The main findings of the study are: First, self-esteem was significantly higher in education major than in other majors. Second, as a result of correlation analysis, self-esteem showed a significant positive correlation with family strength, interpersonal relationship ability, and self-efficacy. Third, as a result of the double mediation effect analysis, interpersonal relationship ability and self-efficacy double mediated in the relationship between family strength and self-esteem. The results of this study can be used as basic data to enhance the self-esteem of college students by utilizing interpersonal relationship ability and self-efficacy.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.223-231
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• 2022

Covid-19, which has made a huge difference in our daily lives, has also brought major changes to our college education. As the class was changed from the traditional face-to-face class to a non face-to-face class, both teachers and students had difficulties in adapting, and problems such as the occurrence of academic achievement gaps due to non face-to-face classes were also raised. Therefore, this study aims to find out what attitudes students have toward non-face-to-face classes at universities caused by Covid-19. Accordingly, this study tried to identify the types of subjective perceptions college students have toward non-face-to-face classes by applying the Q methodology, and to suggest points for reference in the development and improvement of non-face-to-face classes in the future. Five types were found as a result of analysis using 30 P samples and 34 Q samples. First, learning efficiency-oriented type, second, class participation and communication-oriented type, third, non-face-to-face class active acceptance and utilization type, fourth, dissatisfaction type due to remote system and equipment operation errors, fifth, passive response type according to the situation to be. From the results of this study, it seems that it is necessary to develop an educational method for effective non-face-to-face class considering the characteristics of each type, and the merits of non-face-to-face classes, especially recorded lectures, in terms of learning efficiency, are evident. Therefore, even if face-to-face classes are conducted entirely at universities, it is believed that providing video-recorded lectures in class will be of great help to students' learning.

• The Korean Journal of Ecology
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• v.28 no.3
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• pp.135-139
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• 2005

This study was carried out to find the allelopathic effect of volatile materials released from Eupatorium rugosum. The GC method was employed for analysis of volatile materials from E. rugosum and 49 chemical substances were identified such as $\beta$-caryophyllene, $\alpha$-terpinenol, chamazulene, bornyl acetate, $\alpha$-pinene, etc. including unidentified three chemicals. Germination test in Phaseolus radiatus was done to find the inhibition effect of volatile materials using some chemicals which were proved to be important component or much amounts ones in E. rugosum. It was strongly inhibited by linalool and terpinen-4-ol. Seedling elongation and radicle growth of that were proportionally inhibited by the concentration of the essential oil, especially $\alpha$-pinene and bornyl acetate. Biomass of receptor plant was slightly decreased more than 58 ${\mu}l$ of the extract in case of $\alpha$-pinene, while it was decreased more than 19 ${\mu}l$ of that in bornyl acetate but it was shown non-significant. From the above results, it was found that volatile materials from E. rugosum showed a allelopathic effect and also $\alpha$-pinene, bornyl acetate, linalool and terpinen-4-ol used in bioassay were some of major allelochemicals in germination inhibition and especially linalool and terpinen-4-ol are prominent effect on growth inhibition of other plant.

• 한국노년학
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• v.29 no.1
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• pp.215-230
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• 2009

In this study, we compared Korean retirees' retirement wealth adequacy with their subjective recognition and examined determinants affecting the retirement wealth adequacy. The data were drawn from the 2007 Korean Retiree Survey carried out by the Korean Investors Education Foundation. The major results of this study were as follows. The analysis suggested that Korean retirees(age 50 and over) were not well prepared financially. When using their assets(except for their residence), only 23.2% had accumulated enough wealth to meet their expenses for the remainder of their life. 25.7% of retirees subjectively considered themselves to be adequately covered. The comparison results showed that 23.8% of retirees' subjective recognition was not in accord with the estimation results. One of the most troubling groups is the 12.9% of retirees who were in the inadequacy group even though they considered themselves to be in the adequacy group. Retirement wealth adequacy determinants were quite different between objective adequacy and subjective recognition. Household income and ownership of a residence have positive effects on the retirement wealth adequacy. Also, the importance of retirement planning to retirement wealth adequacy is statistically confirmed. Based on these findings, This research suggests private retirement planning and political implications for retirees and preretired households.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.8
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• pp.1335-1343
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• 2013

Parents in South Korea are known for their high level of educational zeal for their children. As a result, their children usually take extra classes in institutions as well as participate in other extracurricular activities such as sports and music. The purpose of this study was to examine the lifestyle and dietary behaviors of Korean elementary students involved in such activities. The total number of subjects was 550 fourth to sixth graders in elementary schools in Sejong, Korea. Of the total subjects, 88.0% were involved in extracurricular classes or other activities for an average of 7.34 hours/week. The subjects were assigned to one of four groups based on the degree of extracurricular activities: No extra-class (n=66), Low extra-class (1${\leq}$taking time<5 hours/week, n=118), Medium extra-class (5${\leq}$taking time<10 hours/week, n=184), and High extra-class (taking time${\geq}$10 hours/week, n=182). More subjects in the High extra-class group went to bed late (P<0.01), were under stress (P<0.01), and skipped breakfast, compared with those in the other groups. The ratio of students who answered 'I go to an institute without a meal' (P<0.01), 'I prepare a meal for myself' (P=0.053), or 'I eat out before going to an institute' (P<0.01) was higher in the High extra-class group than in the Low extra-class group. The frequency of eating fast food was higher in the High extra-class group, compared with the other groups. These results indicate that a high amount of extracurricular studies may have a negative effect on the children's lifestyles and dietary behaviors. Therefore, this study alerts parents to the potential harm of excessive extracurricular activities to their children's health.