• Journal of the Korean Data and Information Science Society
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• v.25 no.6
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• pp.1439-1447
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• 2014

Most of literatures on Korean child aggression are based on using the cross-sectional data sets. Although there is a related study with a longitudinal data set, it is assumed that the data sets measured repeatedly in the longitudinal data are mutually independent. A longitudinal data analysis for Korean child aggression is then necessary. This study is to analyze the effect of child development outcomes including academic achievement, self-esteem, depression anxiety, delinquency, victimization by peers, abuse by parents and internet using time on child aggression with Korea Welfare Panel Study data observed three times between 2006 and 2012. Since Korea Welfare Panel Study data have missing values, the missing at random is assumed. The linear mixed effect model and the restricted maximum likelihood estimation are considered.

• Asia-Pacific Journal of Business
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• v.10 no.4
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• pp.87-118
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• 2019

The purpose of this study is to examine the effects of person-job fit, which consists of educational fit and skill fit, on employees' intrinsic job satisfaction. To the end, the 10-year balanced panel data of the Korean Labor and Income Panel Study(KLIPS) by the Korea Labor Institute (KLI) for 2008-2017 are utilized. This study analyzes 12,730 observations by 1,273 employees by using fixed effect model, random effect model, and pooled OLS estimation method. The empirical results are as follows: First, it is founded that educational fit and skill fit seem affect job satisfaction positively. Second, the negative effects of over-education are clear and the negative effects of under-education are unclear, while the effects of over-skilled and under-skilled are insignificant statistically. Third, the results imply that the size of effect of over-education on intrinsic job satisfaction is larger than that of the effect of over-skilled. Forth, it is shown that the use of fixed effect model is more effective and trustworthy than that of random effect model and pooled OLS estimation method, implying that the effect size of coefficients which are estimated by pooled OLS method and random effect model are likely over-estimated. The empirical results above imply that firms and employees should focus on solving over-education issue before all in order to enhance employees' job satisfaction and it is needed to monitor regularly whether systemic job assignment process is done based on the employees' educational attainment and skill level and to provide more chances for job re-allocation and job rotation.

• Journal of the Economic Geographical Society of Korea
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• v.24 no.4
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• pp.400-410
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• 2021

This study analyzed the determinants of carbon dioxide emissions through the expanded STIRPAT model using panel data from 16 metropolitan cities and provinces in Korea from 2000 to 2019. After testing cross-sectional dependence and coefficient heterogeneity of panel data, we performed analysis using MG, CCEMG, and AMG estimation methods reflected these characteristics. The results of analysis using the AMG estimation method are as follows. The coefficients of income, population, and energy intensity were statistically significant with a positive sign, but urbanization was statistically insignificant. Reduction of carbon dioxide emissions in Korea can be achieved through an increase in energy efficiency and sustainable economic growth. It is necessary to establish a policy that can contribute to sustainable economic growth by inducing productivity improvement through technology innovation reducing carbon dioxide emissions in the long-term as well as building a low-carbon society through active development of carbon dioxide reduction technology.

• Economic Analysis
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• v.27 no.3
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• pp.33-60
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• 2021

This study estimates the fiscal multiplier using Input-Output table panel data from year of 2010 to 2018. Considering the endogeneity of the government expenditure, this study uses the share of government expenditure by sector in the initial period as an instrument variable. The estimation from the panel fixed effect instrumental variables model shows that the estimate for the current period of government expenditure is 1.15~1.22 and the estimate for the cumulative multiplier is 1.23~1.32 depending on the method of controlling time trend. Since the general equilibrium effect absorbed by the time-fixed effect in the estimation equation, the estimated multiplier in this study may be different from the multiplier of the economy as a whole. The general equilibrium effect depends on the response of monetary policy, changes in tax policy, and interaction between sectors.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.20 no.4
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• pp.1-6
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• 2012

The accurate information of mass properties is required for the precise control of the spacecraft. The mass properties, mass and inertia, are changeable by some reasons such as consumption of propellant, deployment of solar panel, sloshing, environmental effect, etc. The gyro-based attitude data including noise and bias reduces the control accuracy so it needs to be compensated for improvement. This paper introduces a real-time inertia estimation method for the attitude determination of STSAT-3, Korea Science Technology Satellite. In this method we first filter the gyro noise with the Extended Kalman Filter(EKF), and then estimate the moment of inertia by using the filtered data from the EKF based on the Recursive Least Square(RLS).

• Journal of the Korean Society for Precision Engineering
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• v.31 no.10
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• pp.947-954
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• 2014

Performance of next generation susceptor is affected by temperature uniformity in order to produce reliably large-sized flat panel display. In this paper, we propose a learning estimation model of susceptor to predict and appropriately assess the temperature uniformity. Artificial Neural Networks (ANNs) and Support Vector Machines (SVMs) are compared for the suitability of the learning estimation model. It is proved that SVMs provides more suitable verification of uniformity modeling than ANNs during each stage of temperature variations. Practical procedure for uniformity estimation of susceptor temperature was developed using the SVMs prediction algorithm.

• Journal of Information Display
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• v.5 no.3
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• pp.1-7
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• 2004

We developed a novel frame interpolation method to interpolate a frame between two successive original frames. Using this method, we are able to apply a double-rate driving method instead of an impulse driving method where a black frame is inserted between two successive original frames. The double-rate driving method enables amelioration of the motion blur of LCDs caused by the characteristics of human vision without reducing the luminosity of the whole screen. The image quality of the double-rate driving method was also found to be better than that of an impulse driving method using our motion picture simulator and an actual panel. Our initial model of our frame interpolation method consists of motion estimation with a maximum matching pixel count estimation function, an area segmentation technique, and motion compensation with variable segmentation threshold. Although salt and pepper noise remained in a portion of an object mainly due to inaccuracy of motion estimation, we verified the validity of our method and the possibility of improvement in hold-type motion blurring.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.217-222
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• 2000

A large Pc structure building is system that consisted of bearing wall and slab joint. It has general structure stability from unity thar each members tied at joint. The strength of mortar that packing in joint among panels is important to internal force in entire building system. Do, if we could get early strength estimation with microwave. It would bring good construction planning, reduce construction time, and judge building stability and so on. The purpose of this study is to develop early estimation method for making better quality control and constructing good PC panel structure. The results of this study were as follows :1) With sealed molds, reduced moisture volatilization to more than 60% and enlarged 30% accelerated compressive strength than before one. 2) To get more accelerated strength, we should control maximum temperature difference to $30^{\circ}C$ downward 3)Interrelation with 7-day and 28-day strength were 0.831,0.902, and it is above than before one

• Journal of Korean Society of Rural Planning
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• v.27 no.2
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• pp.43-48
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• 2021

In this study, an analysis was performed using the growth data and environment data of Korean melon farmers to confirm the influence of environmental factors variables on fruit weight of Korean melon. The analysis results can be summarized as follows. First, it was confirmed that humidity and temperature were recognized as the most important factors among the core factors of korean melon farm production management. Second, The correlation analysis of fruit weight and environmental factors showed a statistically significant soil temperature, internal humidity. Third, The Pooled OLS model estimation results showed that the estimation coefficient for soil temperature is (-), and the estimation coefficient for soil temperature square is (+), indicating that optimal control temperature exists.

• Journal of Climate Change Research
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• v.6 no.4
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• pp.277-281
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• 2015

A Chinese cabbage is one of important vegetables which accounts for more than 60 percent of leaf vegetable. However, cultivation area and yield of Chinese cabbage are steadily decreasing recently. Because meteorological changes destabilize the balance of Chinese cabbage, we need to study on meteorological factors affecting estimation of Chinese cabbage yield. So we conducted a panel analysis using mean temperature, maximum temperature, minimum temperature, precipitation and sunshine's duration from August to November for estimation of Chinese cabbage yield. As the results, we found that if the mean temperature of September increase by $1^{\circ}C$ the amount of production of Chinese cabbage per unit area was increased by 348.6 kg/10a. We also found that the mean temperature of October increased by 174.8 kg/10a, that of November 148 kg/10a, the difference between the maxium temperature and the minimum temperature of October equals 443.3 kg/10a. However, we found that the difference between the maximum temperature and the minimum temperature of November decreased 274.1 kg/10a.