• Food Science and Biotechnology
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• v.15 no.4
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• pp.639-642
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• 2006

The root extract of Scilla scilloides (which has been used as a traditional folk medicine in Korea) was evaluated with regard to antimicrobial, anti-inflammatory, and anti-oxidative activities. The roots of S. scilloides were minced and extracted with 95% ethanol (root:ethanol=25:75, w/v). The inhibitory effects of S. scilloides root extract on the growth of Staphylococcus aureus ATCC 35556, Salmonella enteritidis ATCC 12021, Escherichia coli O157:H7, and Candida parapsilosis KCCM 35428 were tested. The results indicate that the antimicrobial effects of both 0.1 and 1.0% extract of S. scilloides were greater against the growth of S. aureus ATCC 35556 and C. parapsilosis KCCM 35428 than the growth of S. enteritidis ATCC 12021 and E. coli O157:H7. The anti-inflammatory effects were evaluated by measurement of the inhibition of hyaluronidase activity in vitro. It appears that both 0.1 and 1.0% concentrations of extract have inhibitory effects on hyaluronidase relative to the control. Finally, the anti-oxidative effect of 1.0 and 10% extract solutions were measured according to the thiocyanate method and were compared with 1.0% BHT. The results indicate that the anti-oxidative effect of 10% S. scilloides root extract (anti-oxidative index (AOI); $72.3{\pm}4.2$) is not significantly different from that of 1.0% BHA (AOI; $76.8{\pm}3.5$) (p<0.05). However, it appears that the anti-oxidative effect of S. scilloides root extract is at least three-fold greater than that of BHA when accounting for the amount of dissolved solids in each.

• Journal of Korean Medical Science
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• v.33 no.51
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• pp.332.1-332.8
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• 2018

Background: The trend of aging society is occurring globally, and with it, one of the health problems that is emerging is frailty. Efforts are being made to account for the increasing prevalence of frailty, and various modifiable factors are being considered in regards to frailty. Because social contact has shown beneficial effects in terms of health in previous studies, it is increasingly being considered in relation to frailty. The purpose of this study was to assess the association of different types of social contact with frailty status. Methods: A total of 1,200 Korean elders aged 70-84 years old were included in the study. Using Fried's Cardiovascular Health Study index to categorize the frailty status, the relationship between frailty status and frequency of contact (i.e., with family members, friends, or neighbors) was analyzed using multinomial logistic regression accounting for confounders. Results: Adjusting for all covariates, frequency of contact with friends was the most statistically significant. Less frequent contact was associated with a significantly higher odds of pre-frailty: monthly (odds ratio [OR], 2.02; 95% confidence interval [CI], 1.27-3.20), and rarely (OR, 1.87; 95% CI, 1.17-2.99), with daily contact group as reference. Also, those contacting friends monthly (OR, 5.04; 95% CI, 2.29-11.08) or rarely (OR, 3.23; 95% CI, 1.58-6.61) were more likely to be frail compared to the daily group. Conclusion: Frequency of social contact, especially with friends, is strongly associated with frailty.

• Journal of Korea Trade
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• v.25 no.5
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• pp.74-92
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• 2021

Purpose - Utilizing a large sample of Korean firms, this study examines international diversification impacts on corporate tax avoidance and whether firms affiliated with large business groups (known in Korean as "chaebol") reinforce the relationship between international diversification and tax avoidance. Design/methodology - This paper hypothesizes that 1) international diversification is likely to increase tax avoidance, 2) the positive effect of international diversification on tax avoidance is likely to be more pronounced for chaebol firms. We examine the hypotheses by using Korean firms listed in the Korean stock market between 2011 and 2016. We employ the number of foreign subsidiaries and the entropy index as proxies for international diversification and CASH ETR and GAAP ETR as proxies for tax avoidance. Findings - Our findings are summarized as follows. First, we have found that as firms are more internationally diversified, tax avoidance increases. It means that international diversification can be employed as a method of reducing the tax burden. Second, firms affiliated with chaebol are strengthened by the positive relation between international diversification and tax avoidance. It is interpreted that chaebol firms have more effective opportunities to reduce taxes than other firms. When entering foreign markets, they can share experience and resources to decrease taxation within the large business group. Originality/value - This study provides empirical evidence regarding the tax effect of international diversification. Unlike prior studies, international diversification is positively related to tax avoidance in Korea. In addition, we present additional evidence on the chaebol effects of international diversification on tax avoidance, in which they have an advantage to reduce taxes using transfer pricing through related party transactions, income shifting to low tax rate countries, and establishing subsidiaries in tax havens.

• Atmosphere
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• v.28 no.4
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• pp.457-467
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• 2018

This study investigated the variability of spring (March-May) forest fire risk in Korea for the period 1991~2017 and analyzed its relationship with large-scale climate factors. The Forest Weather Index (FWI) representing the meteorological risk for forest fire occurrences calculated based on observational data and its relationship with large-scale climate factors were analyzed. We performed the empirical orthogonal function (EOF) analysis on the spring FWI. The leading EOF mode of FWI accounting for about 70% of total variability was found to be highly correlated with total number of forest fire occurrences in Korea. The high FWI, forest fire occurrence risk, in Korea, is associated with warmer atmosphere temperature in midwest Eurasia-China-Korea peninsula, cyclonic circulation anomaly in northeastern China-Korea peninsula-northwest pacific, westerly wind anomaly in central China-Korea peninsula, and low humidity in Korea. These are further related with warmer sea surface temperature and enhanced outgoing longwave radiation over Western Pacific, which represents a typical condition for a La $Ni\tilde{n}a$ episode. This suggests that large-scale climate factors over East Asia and ENSO could have a significant influence on the occurrence of spring forest fires in Korea.

• Ocean and Polar Research
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• v.44 no.1
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• pp.13-27
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• 2022

The Yeongsan River estuary was altered by a sea dike built in 1981 and the sluice gates in the dike were extended recently in 2014. The construction has caused changes in water properties and hydrodynamics and also produced disturbances including hypoxia and algal blooms. We analyzed the water quality and chlorophyll-a data (2009-2018) collected seasonally at 3 stations (Sts. 1-3) along the channel of the estuary by the Marine Environmental Monitoring System. Variations in water quality and chlorophyll-a (an index of phytoplankton biomass) were examined and their stressors were also identified by statistics including correlation and multivariate principal component analyses (PCA). The water quality was mainly affected by freshwater discharge from the dike. Salinity, nutrients and chlorophyll-a were especially affected by the discharge and the effect enhanced during summer and at the upper region near the sea dike decreasing downstream. Three factors were extracted for each station in the PCA accounting for 66.07-72.42% of the variations. The first was an external factor associated with freshwater discharge and the second and third were seasonal or biological factors. The results indicate that the water quality is more affected by short-termed and episodic events such as freshwater discharge than seasonal events and the influence of freshwater discharge on water quality is more extensive than that previously reported. This suggests that the boundary of the estuary should be extended to take into account the findings of this study and a management strategy linked to the freshwater zone is required to manage the integrity and water quality of the Yeongsan River estuary.

• Journal of Industrial Convergence
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• v.20 no.6
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• pp.135-140
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• 2022

In the domestic stock market, the capital market opened in January 1992, and the proportion of foreign capital has steadily increased, accounting for 30% of the domestic market in Overall stock market trend infers that the domestic stock market is more influenced by foreign issues than domestic issues. The trading trend of foreign capital displays a similar flow to exchange rate fluctuations,; thus, preparing an investment strategy by using the Pearson analyzing method the effect of exchange rates of foreign capital trading, fluctuations in exchange rates, and predicting one of the macroeconomic indicators will yield high returns in the stock market. Therefore, this research was conducted to help investment by predicting foreign variables comparing and analyzing exchange rates and foreign capital trading patterns, and predicting appropriate time for buying and selling.

• Wind and Structures
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• v.34 no.2
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• pp.185-197
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• 2022

This study aimed to analyze the wind-induced mechanical energy (WME) of a proposed super high-rise and long-span transmission tower-line system (SHLTTS), which, in 2021, is the tallest tower-line system with the longest span. Anew index - the WME, accounting for the wind-induced vibration behavior of the whole system rather than the local part, was first proposed. The occurrence of the maximum WME for a transmission tower, with or without conductors, under synoptic winds, was analyzed, and the corresponding formulae were derived based on stochastic vibration theory. Some calculation data, such as the drag coefficient, dynamic parameters, windshielding areas, mass, calculation point coordinates, mode shape and influence function, derived from wind tunnel testing on reducedscale models and finite element software were used in calculating the maximum WME of the transmission tower under three cases. Then, the influence of conductors, wind speed, gradient wind height and wind yaw angle on WME components and the energy transfer relationship between substructures (transmission tower and conductor) were analyzed. The study showed that the presence of conductors increases the WME of transmission towers and changes the proportion of the mean component (MC), background component (BC) and resonant component (RC) for WME; The RC of WME is more susceptible to the wind speed change. Affected by the gradient wind height, the WME components decrease. With the RC decreasing the fastest and the MC decreasing the slowest; The WME reaches the its maximum value at the wind yaw angle of 30°. Due to the influence of three factors, namely: the long span of the conductors, the gradient wind height and the complex geometrical profile, it is important that the tower-line coupling effect, the potential for fatigue damage and the most unfavorable wind yaw angle should be given particular attention in the wind-resistant design of SHLTTSs

• Korea Trade Review
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• v.45 no.5
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• pp.37-53
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• 2020

This study aims to provide the implications of research development by comparing domestic and international studies conducted on the subject of FTA. To this end, among the papers written during the period from 2000 to July 23, 2020, papers whose title is searched by FTA (Free Trade Agreement) were selected as research data. In the case of domestic research, 1,944 searches from the Korean Citation Index (KCI) and 970 from the Web of Science and SCOPUS were selected for international research, and the research trend was analyzed through keywords and abstracts. Frequency analysis and word embedding (Word2vec) were used to analyze the data and visualized using t-SNE and Scattertext. The results of the analysis are as follows. First, in the top 30 keywords of domestic and international research, 16 out of 30 were found to be the same. In domestic research, many studies have been conducted to analyze the outcomes or expected effects of countries that have concluded or discussed FTAs with Korea, on the other hand there are diverse range of study subjects in international research. Second, in the word embedding analysis, t-SNE was used to visually represent the research connection of the top 60 keywords. Finally, Scattertext was used to visually indicate which keywords were frequently used in studies from 2000 to 2010, and from 2011 to 2020. This study is the first to draw implications for academic development through abstract and keyword analysis by applying various text mining approaches to the FTA related research papers. Further in-depth research is needed, including collecting a variety of FTA related text data, comparing and analyzing FTA studies in different countries.

• Journal of Korea Port Economic Association
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• v.27 no.1
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• pp.263-280
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• 2011

The global financial crisis, triggered by the subprime mortgage crisis in 2007, has put the world economy into the recession with financial market turmoil. I tested whether variables were cointegrated or whether there was an equilibrium relationship. Also, Generalized impulse-response function (GIRF) and accumulation impulse-response function (AIRF) may be used to understand and characterize the time series dynamics inherent in economical systems comprised of variables that may be highly interdependent. Moreover, the IRFs enables us to simulate the response in freight to a shock in the USD/JPY exchange rate, Dow Jones industrial average index, Dow Jones volatility, Chinese Import volatility. The result on the cointegration test show that the hypothesis of no cointergrating vector could be rejected at the 5 percent level. Also, the empirical analysis of cointegrating vector reveals that the increases of USD/JPY exchange rate have negative relations with freight. The result on the impulse-response analysis indicate that freight respond negatively to volatility, and then decay very quickly. Consequently, the results highlight the potential usefulness of the multivariate time series techniques accounting to behavior of Freight.

• Journal of Convergence for Information Technology
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• v.10 no.9
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• pp.206-214
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• 2020

This study analyzed the impact of direct and indirect subsidies on profitability in general hospitals in Korea. The data were collected from medical institution accounting information disclosure system of 270 general hospitals from 2016 to 2018. The analysis index used the ratio of net profit to business revenue for profitability, and Subsidies index the ratio of subsidies to business revenue(state subsidies for facility investment purposes, Fund related to essential business, research revenue and contribution revenue). According to the study, the ratio of state subsidies, which are direct subsidies, was very high at 57.30 percent for public institution hospitals. ratio of Fund related to essential business, which is a tax reduction effect with indirect subsidies, had the highest at 6.69 percent for Private University Hospitals. which are Indirect subsidies for deficit or operational assistance, research revenue ratio had the highest 2.8 percent for National University Hospitals, contribution revenue ratio had the highest 36.4 percent for public institutions. As a result of looking at the impact of subsidies on profitability, Nation University Hospitals had the lower the ratio of Fund related to essential business and the ratio of research revenue, the higher the net profit ratio of Business revenue. Medical Corporation Hospitals and Foundation Hospitals had the higher the ratio of Fund related to essential business to business revenues, the higher the net profit ratio of business revenue. These results mean that profitability may fluctuate depending on the utilization of funds related to essential business.