• Education of Primary School Mathematics
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• v.24 no.1
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• pp.1-20
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• 2021

Factors influencing mathematics academic achievement are constantly changing and have direct and indirect effects on mathematics achievement, so longitudinal studies that can predict and analyze their growth are needed. This study uses longitudinal data on students from 2011 (5th grade of elementary school) to 2015 (2nd grade of middle school) of the Seoul Education Longitudinal Study, and divides them into groups with similar longitudinal changes in mathematics academic achievement. The direct and indirect effects of learning attitudes and achievement goals were examined. As a result of the study, it was found that learning effort and learning attitude had a direct effect on mathematics achievement in 1 group (2277 students, 67.7%), and learning attitude had a direct effect on mathematics achievement in 3 groups (958 students, 28.5%). And it was found that learning effort h ad an indirect effect. In addition, it was found that both learning attitudes, learning efforts, and achievement goals had no effect on the academic achievement of mathematics in the second group (127 students, 3.8%).

• Child Studies in Asia-Pacific Contexts
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• v.4 no.1
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• pp.27-45
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• 2014

The present study investigated the developmental pattern of Korean mothers' depressive symptoms from a week prior to birth through four months postpartum in a nationally represented survey sample in Korea, using a Latent Growth Curve model. Mother-reported four factors-maternal self-efficacy in parenting, father's participation in childcare, a number of hours mothers worked per week, child's emotional temperament-were examined as the predictors of depressive symptoms over time in the context of Korean culture. Effects of maternal depressive trajectories on their infants' developmental outcomes at the first year were also examined. Findings were as follows: First, mothers' reports of depressive symptoms decreased at the first month after birth and then increased again during the first 4 months postpartum. Second, mothers' perceived low spousal involvement in childcare, low parental self-efficacy, and their infants' difficult temperament at four-month old had significantly positive relations to the initial level of maternal depressive symptoms whereas the low spousal involvement in childcare and low maternal self-efficacy factors significantly predicted the changes of trajectories of maternal depressive symptoms. Third, the trajectories, in turn, predicted warm and responsive maternal parenting style at the fourth month. Subsequently, the parenting style had a significant longitudinal impact on the development of children's communication, problem-solving, and personal-social abilities. Based on these findings, awareness, preventive and interventional programs might be built to facilitate Korean mothers suffering severe postpartum depressive symptoms and further promote optimal early development of Korean children.

• Human Ecology Research
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• v.56 no.5
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• pp.435-446
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• 2018

This study investigated relationships between primary caregivers' life satisfaction and abuse mediated by children's life satisfaction. We included term panel data for 3 years (2013-2015) from the 4th year to the 6th year of 2,067 children in the first grade of elementary school of the Korean Youth and Youth Panel(KCYPS)(2015); in addition, three years' longitudinal panel data (2013-2015) were analyzed utilizing SPSS 18.0 and AMOS 22.0 to measure Latent Growth Model(LGM) term relationships between variables. Analysis results were as follows. First, the life satisfaction of the primary caregiver, the life satisfaction of the child, and abuse gradually decreased from the fourth grade to the sixth grade. Second, the initial status of primary caregivers' life satisfaction influenced the initial status of the children's life satisfaction, and the initial status and change in the abuse rate. Third, the rate of change of life satisfaction of the primary caregiver did not have a significant effect on the change in the abuse rate and the rate of change of life satisfaction of the child. The initial value of the life satisfaction of the child played a partial mediating role in the relationship between the initial value of the life satisfaction of the primary caregiver, initial value of the abuse, and abuse change rate. The results suggest that a program to improve the life satisfaction of the 4th grade elementary school should be developed and applied.

• The Mathematical Education
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• v.60 no.2
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• pp.191-207
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• 2021

Recently, the number of multicultural families has significantly increased in Korea, and this trend creates a need to understand how successfully students from multicultural families achieve their mathematics learning. To understand and predict the changes in mathematics learning achievement of these students over time, we conducted in this study a latent growth mixture model analysis. The study findings show that the majority (92%) of the students from multicultural families experience a decrease in their mathematics achievement over time as their grade level goes up. It was found, in particular, that female students are likely to have lower initial achievements and rapid decline over time more than male students and that the decline over time was more severe for female students than their male counterparts. The findings of this study convey several implications on the how to support the students from multicultural families. First, the result of this study was different from the outcomes of previous studies that presented the income of the household and the education level of the students' parents as major factors that determine the academic achievement of the students from multicultural families. Furthermore, the study indicates the need for more research to identify variables related to the mathematical achievements of the students from multicultural families and the need to use these research findings to develop public support plans for the students from multicultural families.

• Journal of Digital Convergence
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• v.7 no.3
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• pp.123-135
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• 2009

The considerable progress of IT industry has changed the industrial structure and lifestyle of our society. One of the remarkable fields of IT industry is online game industry. It showed rapid growth for the past decade. But in recent years online game industry faced with the limit of its growth for a number of reasons. To overcome such situation, online game companies should improve functions of game and analyze their customer's needs for sustainable growth through increasing customer satisfaction and loyalty. The purpose of the study is to investigate and evaluate the factors of online game service quality and the relation of customer satisfaction and loyalty. SPSS 14.0 and AMOS 7.0 are used for experimental research. Through reliability and validity test, service quality factors influencing the customer satisfaction are appeared to be 5 latent variables(reliability, responsiveness, assurance, empathy, tangibles). In addition, by structural equation model and covariance structural model, the result showed that empathy is the most influenced factor to customer satisfaction and customer satisfaction has positive effect on customer loyalty. The results of this research have important implications for explaining an mechanism for service quality of online game, customer satisfaction and loyalty and they might provide operational guidelines to the online game service company.

• Journal of Family Relations
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• v.23 no.1
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• pp.3-24
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• 2018

Objective: This study examined the change of informal labeling self-respect, depression/anxiety, and aggression of adolescents over time and relationship between the intercept and the growth of the variables. Method: 4-year longitudinal panel data(n=2,699), Korea Youth Panel Survey (KYPS), were analyzed to verify the influence of informal labeling on self-respect, depression/anxiety, and aggression of adolescents. Through latent growth modeling, temporal change of the variables was examined. Results: Analytic results are as follow. First, the initial status of informal labeling had a negative impact on the initial status of self-respect. The slope of informal labeling also had a negative impact on the slope of self-respect. In contrast, the initial status of informal labeling did not have an significant impact on the slope of self-respect. Second, the initial status of informal labeling had a positive impact on the initial status of aggression. The slope of informal labeling had a negative impact on the slope of aggression. In contrast, the initial status of informal labeling did not have an significant impact on the slope of aggression. Third, the initial status of informal labeling had a positive impact on the initial status of depression/anxiety and a negative impact on the slope of depression/anxiety. The slope of informal labeling had a positive impact on the slope of self-respect. Conclusions: The results suggest the importance of informal labeling on self-respect, depression/anxiety, and aggression of adolescents.

• The Mathematical Education
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• v.61 no.1
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• pp.127-156
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• 2022

This study used the data of students from the 6th grade to the 3rd grade of middle schoolin the Korean Educational Longitudinal Study 2013 and classified them into subgroups with similar longitudinal changes in math academic achievement. In addition, the influence of longitudinal changes in the group's academic self-concept and teachers and parents academic support on the longitudinal changes in math academic achievement were analyzed, either directly or indirectly. As a result of the analysis, it was found that the academic self-concept of each group had a positive influence on the academic achievement in mathematics. In addition, the academic support of teachers and parents was found to have a positive influence on the academic achievement in mathematics through the mediating of the academic self-concept. In terms of direct and indirect influence on academic self-concept and math vertical scale scores, it was found that teachers' academic support had more influence than parents' academic support. The educational implications of these points were discussed.

• Korean Journal of Social Welfare Studies
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• v.40 no.3
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• pp.377-406
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• 2009

This study used laten class growth analysis to identify discrete developmental patterns of delinquent behaviors in adolescence. This present article also examined associations among these trajectories to determine how the development of delinquent behaviors relates to protective and risk factors, which include parental monitoring, attachment with parent, association with deviant peers, self-control, and negative stigma from others. Four-wave panel data from a Korea Youth Panel Study were used for the latent class growth model analysis. The sample consisted of 3,446 adolescents who were assessed at 4 measurement waves with approximately 1-year interval. Four trajectories of delinquent behaviors emerged: delinquency persistence, delinquency increaser, delinquency decreaser, normative group(almost no delinquent behaviors). Association with deviant peers had the most proximal strong influence on the probability of being in the delinquency increaser and delinquency persistence group compared, noed to the normative group. Parental monitoring, self-efficacy and negative stigma also differentiated the four delinquent behavior trajectories from one another after controllig for socio-demographic variables. The study suggested that there is a significant heterogeneity in the timing and change rate of delinquency progression. Adolescent delinquency prevention and intervention programs will need to consider this heterogeneity and enhance attention to protective and risk factors depending on the subpopulation.

• Korean Journal of Culture and Social Issue
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• v.28 no.3
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• pp.331-352
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• 2022

This study used a latent growth curve models(LGCM) to examine longitudinal changes in youth's game usage, self-control and the longitudinal mediation effect of adaptive game use in the relationship between game usage and self-control. A four-year longitudinal data of 863 adolescents from the Game User Panel Survey, provided through participation in the 2019 Game User Panel Research Conference hosted by the Korea Creative Contents Agency, was used to verify the longitudinal mediation effect of adaptive game use. SPSS 21 was used to verify the normality of variables from each wave, and to conduct correlation analysis. Mplus 6.12 was used to verify the longitudinal mediation effect. The results are as follows. First, game usage, self-control and adaptive game yielded linear temporal growth. Second, latent growth curve models showed that the direct effect of game usage on self-control was insignificant, but game usage had a significant indirect effect on self-control through adaptive game use. Continuous adaptive gaming increased self-control. Third, sobel test results showed that both the initial value and change rate of adaptive game use had a full-mediation effect, confirming the longitudinal mediation effect. This study verified the longitudinal change of self-control affected by change in game usage and adaptive game use.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2334-2339
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• 2008

This paper proposes an improved mathematical model for predicting the frosting behavior on a two-dimensional fin considering the heat conduction of heat exchanger fins under frosting conditions. The model consists of laminar flow equation in airflow, diffusion equation of water vapor for frost layer, and heat conduction equation in fin, and these are coupled together. In this model, the change in three-dimensional airside airflow caused by frost growth is accounted for. The fin surface temperature increased toward the fin tip due to the fin heat conduction. On the contrary, the temperature gradient in the airflow direction(x-dir.) is small throughout the entire fin. The frost thickness in the direction perpendicular to airflow, i.e. z-dir., decreases exponentially toward the fin tip due to non-uniform temperature distribution. The rate of decrease of heat transfer in the airflow direction is high compared to that in the z-direction due to more decrease in the sensible and latent heat rate in x-direction.