• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.4
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• pp.274-284
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• 2014

Crops and varieties are mostly affected by temperature, the amount of precipitation, and duration of sunshine. This study aims to identify the weather factors that directly influence to apple yield among the series of daily measured weather variables during growing seasons. In order to identify them, 1) a priori natural scientific knowledge with respect to the growth stage of apples and 2) pure statistical approaches to minimize bias due to the subject selection of variables are considered. Each result estimated by the Panel regression using fixed/random effect models is evaluated through suitability (i.e., Akaike information criterion and Bayesian information criterion) and predictability (i.e., mean absolute error, root mean square error, mean absolute percentage). The Panel data of apple yield and weather factors are collected from fifteen major producing areas of apples from 2006 to 2013 in Korea for the case study. The result shows that variable selection using factor analysis, which is one of the statistical approaches applied in the analysis, increases predictability and suitability most. It may imply that all the weather factors are important to predict apple yield if statistical problems, such as multicollinearity and lower degree of freedom due to too many explanatory variables used in the regression, can be controlled effectively. This may be because whole growth stages, such as germination, florescence, fruit setting, fatting, ripening, coloring, and harvesting, are affected by weather.

• KDI Journal of Economic Policy
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• v.28 no.2
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• pp.131-177
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• 2006

This paper examines a simultaneous determination of corporate control mechanisms, and its effects on firm performance. The corporate control mechanisms considered include the following; insider shareholding, institutional shareholding, the board of directors, dividend policy, and capital structure. This paper applies a simultaneous equation methodology and investigates the interdependence among the corporate control mechanisms. In the first part, the paper finds that firm-level variations of control mechanisms are large across time although average variations are relatively small. These variations are related to one another, which is confirmed by Granger causality test based on dynamic panel autoregression model. More specifically insider shareholding, institutional shareholding and outside director ratio cause each other. With regard to interdependence among the control mechanisms, 2SLS(two stage least squares) regression results show that insider shareholding and institutional shareholding are substitutes while institutional shareholding acts as complements to the ratio of outside members in the board of directors. Then in the second part, the paper examines the relationship between firm performance and corporate governance. Firm performance, measured by Tobin's Q, has a positive association with leverage ratio while that has a negative relation to outside director ratio. This suggests that there may be a room for reforming corporate governance in Korea. Specifically it is necessary to enhance the independence of the outside directors.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.355-362
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• 2018

This study aims to examine the relationship between physical education class activity of youth, smartphone dependence and school life adaptation. The data set of Korean Children and Youth Panel Survey(KCYPS) by National Youth Policy Institute was reanalyzed for this study. The subjects of this study were 2,351 second grade middle school students from 2011. The data were coded with the use of the statistics program on Windows, SPSS 23.0. To analyse the data, descriptive analysis, reliability analysis, one-way ANOVA and regression analysis were employed. The findings of this research are as follows. First, the difference between the activity hours of youth physical education classes and the reliance on smartphones is less dependent on smartphones as they participate enthusiastically in physical education classes. Second, the difference of physical education class activity time and school life adaptation among adolescents was more positive for school life adaptation as learning activity, peer relationship and teacher relationship were more active. third, the dependence of youth on smartphones has a positive effect on learning activities and school rules as the reliance on smartphones is low.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.446-453
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• 2018

This study analyzed the effect of related party transactions on the corporate value of Korean firms using panel data regression analysis. We tested the efficient transaction hypothesis and conflict of interests hypothesis which concern related party transactions. Five types of related party transactions were considered, including long term supply contracts, assets and business transfers, affiliate loans, equity investment, and credit offerings. If related party transactions were conducted for the purpose of enhancing corporate efficiency, results would have a positive effect on firm value. If related party transactions were conducted for the purpose of private profits of the controlling shareholders, the results would show a negative effect on firm value. Results were as follows. Firstly, it is confirmed that affiliate loans, equity investment, and credit offerings had negative effects on firm value. This implies that these types of related party transactions used by controlling shareholders for the purpose of their private profit, which supports the conflict of interests hypothesis. Secondly, it was found that long term supply contracts and assets and business transfers had no effect on firm value.

• Journal of the Korean Regional Science Association
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• v.33 no.4
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• pp.3-17
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• 2017

This study ranks by developing an urban competitiveness index of major global cities, including seven cities in Korea using data from the Global Cities Forecast (2013) provided by Oxford Economics. The City competitiveness index is selected from 18 indicators including scale index, ratio index, growth rate index while Gini coefficient is used for distribution index. In order to analyze the relationship between the competitiveness index and the distribution index, we use the LOGIT panel regression model. As a result, the increase in income inequality (Gini coefficient) has a negative effect on the economic growth rate in 5-year time lag shown statistically significant. We have compiled global rankings of 770 city competitiveness based upon 19 indicators by combining the global competitiveness index and the distribution index. The trend of rank shows that 7 Metropolitan Korean Cities are expected to decline substantially over the period. In particular, Seoul ranked $59^{th}$ in 2010 and $74^{th}$ in 2015. Its ranking is expected to be decline to $185^{th}$ in 2030. The declining competitiveness of Korean cities is expected to lead to a weakening of Korea's national competitiveness in the long run. Accordingly, it is imperative to identify problems and seek strategic plans to secure global urban competitiveness.

• Journal of Navigation and Port Research
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• v.43 no.4
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• pp.264-272
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• 2019

In this study, the rate of return on investment used as a proxy variable for the entity's value and financial structure (liability ratio) is related to positive balance. This is consistent with the Static Tradeoff Theory (STT) that the entity's value and financial structure are related to a positive balance because the capital expense of a debt (tax-saving effects) that is less than its equity cost before it is in financial difficulty. Also, operating profitability (EBITDA/Sales), investment safety, total asset growth, net working capital and depreciation expenses are related to negative (-) with financial structure (liability ratio). This is the result of an analysis consistent with the Pecking Order Theory (POT). Fuel costs, borrowing, total asset turnover, financial costs, and tangible asset ratios have a significant positive relationship with the debt ratio. This is consistent with the agency theory and confirms that excessive chartering expenses, such as the bankrupt H company, are the main factors that pressure the financial structure of Korean ocean carriers.

• 한국노년학
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• v.37 no.1
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• pp.15-32
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• 2017

The current study aims to identify the heterogeneous changes of functional disabilities in old age rather than to identify an average longitudinal pattern and to explore the effect of health status and social status as risk factors in functional disability trajectories. The sample consisted of a representative sample of community dwellers aged 65 and older from the Korean Longitudinal Study of Ageing (2006 - 2012) was the focus of the study. Latent Class Growth Analysis was used to identify the functional disability trajectory groups. Variables regarding health status and social status changes by class were identified using multinomial logistic regression. The results showed various change patterns in functional disability, which include independent (78%), stable high (4.4%), steeply increasing (7.1%), slightly increasing (5.5%), and moderate to low (4.7%). Aggravation in depressive symptoms and cognitive functions as well as decline in social participations and social engagements were significant predictors of membership in increasing group of functional disability. The findings provide important initial empirical information to target clinical practice and have implications in the importance of conducting research on groups with different characteristics.

• The Journal of the Korea Contents Association
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• v.21 no.4
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• pp.278-291
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• 2021

This study performed a longitudinal research on the causal relationship between multidimensionality of problem drinking and poverty, and multidimensional deprivation meaning the inequality, focusing on gender difference. For this, this study examined the latent group of problem drinking change trajectory through the latent class growth analysis targeting total 3,770 men and 5,632 women by using the 6th-year Korea Welfare Panel Study data from 2013 to 2018, and then conducted the multinominal logistic regression analysis to verify the influence of multidimensional deprivation factors on this latent group. The main results of this study are as follows. First, the latent group of problem drinking change trajectory according to gender was classified into three latent groups in both men and women while the development aspect was different from each other. The male latent group with 'moderate level' or higher showed higher level of problem drinking than women. However, in case of 'drinking group with high level' according to gender, as time passed, the men tended to maintain it while the women tended to increase it. Second, in the results of examining the effects of multidimensional deprivation on the latent group of problem drinking change trajectory, the men with more experiences of social deprivation and the women with more experiences of social security deprivation showed the higher possibility to belong to the 'drinking group with high level' compared to the 'drinking group with low level'. Based on such results above, this study discussed the preventive/intervention measures for problem drinking according to gender.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.541-549
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• 2020

This study conducts differential analysis on the financial positions of Korean shipping companies before and after the bankruptcy of the H carrier, looking specifically at their financial ratios, profit and loss patterns, and other factors related to their financial operation. Firstly, it was discovered that major measures of financial health, such as average assets per carrier, were not affected by the bankruptcy of the H carrier. However, despite this, most carriers experienced large changes in profits and losses, with total sales and shipping revenues averaging 424.5 billion won and 381.7 billion won respectively before the bankruptcy, but falling by half to 252.1 billion won and 234.6 billion won after the bankruptcy. Additionally, charter revenues and expenses also dropped by more than half. EBIT/sales and pre-tax revenue margins were also heavily affected after the bankruptcy, with both figures averaging 8% and 3% respectively before the bankruptcy, but falling into the negative range at -2% and -8% post-bankruptcy, resulting in significant deterioration in operational profitability. The study concludes that there is an urgent need to establish a global sales network, improve cost structures, and consistently secure stable cargo in order to increase Korean carriers' profitability. Of all financial measures, liquidity and total asset efficiency were identified as the most severely-impacted by the H carrier bankruptcy, thereby requiring the most pressing policy addressing.

• 한국사회정책
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• v.24 no.4
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• pp.185-222
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• 2017

The purpose of this study is to investigate the effect of labor market policy on fiscal soundness of welfare state. The analysis was carried out using cross-sectional panel data regression analysis, stepwise mediating effect analysis and system GMM designed by Baron and Kenny(1986) based on the data from 1985 to 2015 for 20 OECD countries. In setting up the analysis model, this study considers the interaction effect between active and passive labor market policies as well as the time sequence of the outcomes which have been overlooked in the previous studies. The result shows that labor market policies have significant impacts on the fiscal condition of welfare states, which is measured as the levels of national debt in this study. Especially the expenditure on active labor market programs has a positive effect on improving the fiscal soundness of welfare states by promoting the employment rate. In contrast, passive labor market programs expenditure is negatively associated with employment rate growth and it exacerbates the burden of national debt in the short-term. However, when active labor market programs and passive labor market programs are combined, the negative impacts by passive pabor market policies on the fiscal soundness of welfare states are off-set. Therefore this study addresses that although the expansion of the labor market policies can be inimical to the fiscal soundness of welfare states in the short-term, in the long run, they can have effective roles in securing and promoting the fiscal soundness of the welfare states by promoting the employment rate.