• Journal of the Korean Data and Information Science Society
• /
• v.28 no.1
• /
• pp.1-10
• /
• 2017

Longitudinal data of Korean child academic achievement have been used to find the significant exploratory variables under the assumption of independent repeated measured data. Using the exploratory variables in previous research works, we analyze the linear mixed model incorporating the fixed and random effects for child academic achievement to detect the significant exploratory variables. Korea welfare panel study data observed three times between 2006 and 2012 by additional survey for children. The child academic achievement is evaluated by the sum of academic achievements of Korean, English and Mathematics. We also investigate the multicollinearity and the missing mechanism and select some popular correlation matrices to analyze the linear mixed model.

• Journal of Korea Port Economic Association
• /
• v.31 no.1
• /
• pp.171-188
• /
• 2015

Logistics network has been increasingly acknowledged as one of the important driving force for economic development in China. With the scope of logistics effect broadening and the development of logistics infrastructure, both logistics network and economy in terms of GDP in China has experienced rapid development hand in hand. This paper investigates the relationship between logistics network and economic growth, using a dataset covering 31 provinces over the period from 2003 to 2012 in China. Factor analysis is applied to obtain a total evaluation of logistics function defining the impact of logistics network on the national economy growth. According to fixed effect panel data approach, a significant and positive impact of logistics network on economic growth in China is found, meanwhile, a comparative analysis regarding economic development between coastal provinces and interior provinces is also conducted. The results suggest that the impact of logistics network on economic growth is higher in eastern provinces than that in western provinces. The policy implication for other nations, in particular for developing nations, is logistics network should be regarded as an important driving force for economic development, and investment should be made in advance to achieve the best efficiency in economic development and planning.

• Journal of Convergence for Information Technology
• /
• v.12 no.4
• /
• pp.286-302
• /
• 2022

This study examined the dynamic role that automation has had upon employment, productivity, and profitability. For the analysis, 342 companies of the Workplace Panel Survey of the Korea Labor Institute conducted from 2005 to 2015 was used. For analytical models, the fixed effect model, which is capable of controlling the endogeneity problems of variables, was used. According to the analysis results, the increased ratio of automation in Korean companies (1) resulted in the increase of turnover in the short and long terms, a temporary decrease in employment, and (2) a decrease of productivity in the short and medium terms, and thereby (3) failing to change profitability in a positive manner.

• Economic Analysis
• /
• v.25 no.3
• /
• pp.1-29
• /
• 2019

This paper examines the impact of a dual labor market structure on labor productivity using unbalanced panel data from 29 OECD member countries between 1990 and 2015. By applying a variety of regression models on the panel data (e.g., a pooled regression, a fixed effects model and a GMM), we explore how changes in worker-type composition among temporary, permanent and self-employed workers contribute to productivity growth. While it appears that our results differ slightly, depending on the econometric models, overall an increase in the share of permanent workers leads to a relatively higher increase in productivity growth. On the other hand, it is also seen that the effects of the share of temporary workers on labor productivity are considerably lower than that of permanent and self-employed workers. To sum it up, our findings indicate that an increase in temporary workers could have an adverse effect on labor productivity.

• Environmental and Resource Economics Review
• /
• v.27 no.3
• /
• pp.463-493
• /
• 2018

As the population structure of Korea changes with the increase of single households and elderly households, this may have effect on domestic energy consumption pattern. Our study analyzes whether the energy consumption of single and elderly households are distinguishable from those of general households. For empirical analysis, Household Energy Standing Survey panel data and regional fixed effect model are employed. The result strongly shows that single households consume more energy than other households. The consumption of single households from 40s to 60s was the highest. On the other hand, the effect of aging was different from energy sources. Electricity consumption of elderly household was more than other age groups, while oil consumption of elderly household was less than others. Gas and total energy consumptions turned out to be not much different among different age groups.

• Korean Journal of Social Welfare Studies
• /
• v.47 no.1
• /
• pp.205-232
• /
• 2016

The purpose of this study is to analyze the bilateral and autoregressive relationships of corporate social performance and corporate financial performance by using dynamic panel model based on fixed effect analysis method. To satisfy this study purpose, 6 years data (2008-2013) of top 1,000 corporations in Korea was collected and finally 430 corporations were used for dynamic panel analysis. The main results were as follows. First, the preceding financial performance explains the following corporate social performance in positive direction. Second, the preceding corporate social performance does not explain the following financial performance. Third, the preceding corporate social performance explains the following corporate social performance in positive direction. Fourth, the preceding financial performance explains the following financial performance in positive direction. This result shows that slack resources theory is supported and good management theory is not supported. In addition, there is a significant relationship between the preceding corporate social performance and the following corporate social performance. Lastly, this study broadens and deepens previous understanding on corporate social philanthropy and discusses theoretical meanings and implications for future study.

• KDI Journal of Economic Policy
• /
• v.41 no.1
• /
• pp.1-14
• /
• 2019

This paper studies whether export diversification mitigated the negative effect of the global financial crisis on exports using the Korean case. Specifically, we use annual data on the exports of 24 Korean manufacturing industries from 2000 to 2016 and examine whether the negative effect of the crisis on exports was less prevalent in industries that were more diversified in terms of country and product. We also examine whether export competitiveness, as measured by the revealed comparative advantage index by industry, had a mitigating effect on trade during the crisis. In order to study these issues, we use panel regression with a fixed-effect model for 24 Korean manufacturing industries. From our empirical analysis, we find that country diversification weakened the negative impact of the global financial crisis on Korea's exports, whereas neither product diversification nor export competitiveness did so.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2023.11a
• /
• pp.113-114
• /
• 2023

As the available resources are gradually depleted, interest in renewable energy is increasing. Various energy harvesting technologies are emerging, and energy harvesting using solar, solar, and wind power is used in the highest range. Depending on the abnormal climate, solar heat and solar power differ in energy harvest, but the wind is fixed compared to the sun. Therefore, it was intended to maximize the effect of energy harvesting by using the venturi effect, which has a change in wind speed according to the turbine used for wind power generation and wind pressure. Therefore, in this paper, we want to see the difference in the amount of power generated by the turbine after increasing the wind speed using the venturi effect.

• Proceedings of the Technology Innovation Conference
• /
• 1996.12a
• /
• pp.265-295
• /
• 1996

This paper investigates empirically the relationship between various business portfolio properties (particularly technological properties) and chaebol′s performance using data on the 50 largest chaebols in Korea. In addition to the traditional indexes to measure diversification such as entropy index we calculated inter-industry technological similarity using R&D expenditure data by industry and 1990 Input-output Table in Korea, and obtained chaebol-level technological relatedness and internal transaction proportion from chaebols′business profile, inter-industry technological similarity and 1990 input-output table. We applied factor analysis on 13 business portfolio property indexes and showed that they could be grouped into 3 dimensions, diversification scope, inter-business relatedness and degree of vertical integration. In this paper, using 50 largest chaebols′financial data (1989-1994), we analyzed empirically the effect of business portfolio properties on ROS (Return On Sales) which is conventional index for firm performance and on TFP(Total Factor Productivity) growth which is a pure measure of firm performance. To utilize the advantage of panel data, FEM(Fixed Effect Model) and REM(Random Effect Model) were used. The empirical result shows that the entropy index as a measurement of inter-business relatedness is not significant but technological relatedness index is significant. OLS estimates on pooled data were considerably different from FEM or REM estimates on panel data. By introducing interaction effect among the three variables for business portfolio properties, we obtained three findings. First, only VI (Vertical integration) has a significant positive correlation with ROS. Second, when using TFP growth as an dependent variable, both TR(Technological Relatedness) and f[ are significant and positively related to the deepened variable. Third, the interaction term between TR and VI is significant and negatively affects TFP growth, meaning that TR and VI are substitutes. These results suggest strategic directions on restructuring business portfolio. As VI is increased, chaebols will get more profit. A higher level of either TR or W will increase TFP growth rate. but increase in both TR and VI will have a negative effect on TFP growth. To summarize, certain business portfolio properties such as VI and TR can be considered "resources" themselves since they can affect profit rate and productivity growth. VI and TR have a synergy effect of change in profit rate and productivity growth. VI increases ROS and productivity growth, while TR increases productivity growth representing a technological synergy effect.

• Journal of Korean Society of Transportation
• /
• v.29 no.4
• /
• pp.95-101
• /
• 2011

This study proposes the accident estimation model developed based on the time-series cross-sectional data at 50 intersections in Cheongju. The data were collected repeatedly and accumulated from 2004 to 2007. This study focused on deriving the optimal among the various models including TSCSREG(Time Series Cross Section Regression). Four different models utilizing various elements affecting accidents were developed. Through a statistical test, it was found that the t values of independent variables of the fixed effect models were less than those of the random effect models. Two variables were then found to be positive to the accidents: the number of crosswalks at an intersection and the number of intersections.