• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.491-497
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• 2018

This study analyzes the relationship between R&D input and performance using panel data from the defense industry. A research model is established based on the R&D logic model, and the study sample consists of a strongly balanced panel data (n=351) empirically analyzed using panel linear regression. Results identified that defense improvement expenditure has a positive influence on the R&D input, and R&D input positively affected patents using a 5-year time lag. In addition, R&D input positively impacts economic performance, including sales and profit. Hence, the major finding includes R&D inputs have statistically significant effects on economic outcome and the R&D logic model featuring a time-lag.

• The Korean Journal of Applied Statistics
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• v.35 no.6
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• pp.703-724
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• 2022

Although longitudinal studies mainly produce multivariate longitudinal data, most of existing statistical models analyze univariate longitudinal data and there is a limitation to explain complex correlations properly. Therefore, this paper describes various methods of modeling the covariance matrix to explain the complex correlations. Among them, modified Cholesky decomposition, modified Cholesky block decomposition, and hypersphere decomposition are reviewed. In this paper, we review these methods and analyze Korean children and youth panel (KCYP) data are analyzed using the Bayesian method. The KCYP data are multivariate longitudinal data that have response variables: School adaptation, academic achievement, and dependence on mobile phones. Assuming that the correlation structure and the innovation standard deviation structure are different, several models are compared. For the most suitable model, all explanatory variables are significant for school adaptation, and academic achievement and only household income appears as insignificant variables when cell phone dependence is a response variable.

• Korean Journal of Construction Engineering and Management
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• v.12 no.3
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• pp.11-21
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• 2011

The most critical issue in free-form buildings is how to construct the free-formed exterior facade panels. Their geometric complexity delivers many cons and problems in fabricating and constructing their shapes. To construct a free-form building, first of all, its skin has to be chopped into small pieces, which is called panelization. After panelization, the panels go through an optimization process to construct them economically. The panel's geometries are modified or regenerated through this optimization process. In this study, the panel optimization process of free-form buildings are performed through a case study. The panel shapes of the case study are modeled with Digital Project. To test the constructability of the various panels, 8 mock-up panels are made and laser scanning technology is applied to measure the preciseness of the panels manufactured in comparison with their original design.

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

• Korean Business Review
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• v.15
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• pp.79-97
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• 2002

In this study, an analytical CRM for customer segmentation is exercised by integrating and analyzing the customer profile data and the access data to a particular web site. We believe that effective customer segmentation will be possible with a basis of the understanding of customer characteristics as well as behavior on the web. One of the critical tasks in the web data-mining is concerned with both 'how to collect the data from the web in an efficient manner?' and 'how to integrate the data(mostly in a variety of types) effectively for the analysis?' This study proposes a panel approach as an efficient data collection method in the web. For the customer data analysis, OLAF and a tree-structured algorithm are applied in this study. The results of the analysis with both techniques are compared, confirming the previous work which the two techniques are inter-complementary.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.181-182
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• 2020

본 연구는 다문화청소년 패널데이터 3차년(2013년)부터 7차년(2017년)까지 패널조사 데이터를 활용하여 다문화청소년의 이중문화수용성이 성취동기에 미치는 영향에 있어 시간의 흐름에 따른 변화를 분석하고자 한다. 이를 위해 잠재성장모형을 이용한 이중문화수용성과 성취동기 간의 상관관계 및 인과적 관계를 규명하는 방법을 적용하였다.

• Journal of Labour Economics
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• v.41 no.3
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• pp.161-186
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• 2018

Albeit numerous endeavors in matching names and surveying inventors, inventor-level studies of patent data have been scarce because unique inventors can not be identified across patents. Using the Korean patent data with inventor IDs, birth year, and gender available, we construct unique inventor-level panel data. As the first undertaking with our data, we investigate the age profile of patent productivity among inventors. We find an inverted U-shaped profile with the peak at age 31. We also find an increasing productivity for younger cohorts of inventors. These findings are robust after we control for the calendar year effects and the quality of patents.

• Korean Journal of Culture and Social Issue
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• v.22 no.1
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• pp.65-85
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• 2016

In this study, we examined the longitudinal change of multicultural acceptability, peer relationship, and teacher relationship using latent growth curve modeling. This study used data from the second, third, and fourth waves of the middle school student cohort (N=2,178) of the Korean Children-Youth Panel Survey (KCYPS). The dependent variable was multicultural acceptability. The independent variables were peer relationship and teacher relationship. The major longitudinal findings of this study are as follows: First, peer relationships, teacher relationships and multicultural acceptability increased with time. Second, peer relationship showed a significant effect on the multicultural acceptability over time. Finally, the teacher relationship showed a significant effect on the multicultural acceptability over time. These results show differentiation with previous cross-sectional studies of multicultural acceptability. Furthermore, it is expected that this study will provide educational implications for the cultivation of multicultural acceptability.

• Journal of the Korean Data and Information Science Society
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• v.24 no.6
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• pp.1409-1419
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• 2013

We analyzed the data from KYPS using the latent growth model which has been widely studied as an analysis method of longitudinal data. In this study, we applied repeated measures ANOVA to unconditional model in order for faster decision of the unconditional model of the latent growth model. Also, we compared the six-type models, the quadratic model and the model of which repeated measures ANOVA is applied.

• Korea Trade Review
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• v.48 no.2
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• pp.71-94
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• 2023

The purpose of this study is to prove the effect of psychic distance between home country and host country on overseas foreign direct investment(OFDI) of Spanish companies through panel analysis. The panel data was based on cultural, institutional, economic, and geographical distance data over the past decade between Spain and Spain's OFDI countries. According to the Random Effect Model(REM) analysis, cultural distance(CULD) had a negative effect on OFDI, while institutional distance(INSD) had a positive effect. Among economic distances, income size distance(GDP) had a positive effect on OFDI, but export size distance(EXPO) had a negative effect. Geographic distance(PKM) had a negative impact. Meanwhile, according to the results of quantile regression analysis to prove the psychic distance effect by OFDI size, the effects of CULD and INSD in the quartile (75%) to which Korea belongs were the same as the REM analysis results. In addition, GDP and EXPO had a positive effect, and PKM had a negative effect but EXPO had a positive effect. Therefore, FDI host countries need to establish differentiated strategies through quantile analysis while making continuous efforts to improve the system.