• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.370-379
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• 2020

The purpose of this study is to estimate the longitudinal changes in the academic achievement of Korean adolescents who transition from elementary to middle school and examine the individual and social factors of the changes using piecewise growth modeling. For this study, the Multicultural Adolescents Panel Study (MAPS) data from 1st to 6th waves (4th-9th grade) were used. The results are as follows. First, the results showed that the piecewise growth function was the most appropriate method to explain changes in the academic achievement of Korean adolescents with respect to the time of vacation. Second, adolescents' academic achievement declined constantly and was greater for middle school students. Third, parental efficacy, self-esteem, and support from friends had a significant positive effect, while uninvolved parenting and acculturation stress had a significant negative effect on the initial value of academic achievement. Self-esteem and support from friends in the 4th grade prohibit its decline in the first change rate of academic achievements. Meanwhile, acculturation stress for 4th-grade students accelerates the decline of academic achievement.

• Korean journal of applied entomology
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• v.26 no.1 s.70
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• pp.31-36
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• 1987

A piecewise linear regression model able to describe disease progress curves with simplicity and flexibility was developed in this study. The model divides whole epidemic into several pieces of simple linear regression based on changes in pattern of disease progress in the epidemic and then incorporates the pieces of linear regression into a single mathematical function using indicator variables. When twelve epidemic data obtained from the field experiments were fitted to the piecewise linear regression model, logistic model and Gompertz model to compare statistical fit, goodness of fit was greatly improved with piecewise linear regression compared to other two models. Simplicity, flexibility, accuracy and ease in parameter estimation of the piece-wise linear regression model were described with examples of real epidemic data. The result in this study suggests that piecewise linear regression model is an useful technique for modeling plant disease epidemic.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.190-198
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• 2020

The purpose of this study was to investigate the changing trajectory of self-esteem and to explore contemporaneous and lagged effects of social supports(family, friends, and teacher) of 4th graders in elementary school to 9th graders in middle school. The subjects were 1,296 multiethnic students, who participated in the Multicultural Children and Adolescents Panel Study(MCAPS) from 2011 to 2016. The results of piecewise growth function showed that students' self-esteem was increased during upper grade in elementary school but soon deceased during middle school. Individual differences were found at initial, 1st and 2nd changing status. Students with higher level at initial status in self-esteem showed less increased pattern during elementary school but greater decreased pattern during middle school. In addition, supports from family and teacher showed contemporaneous effects across all 6 years while supports from friends showed such effects only for 5 years except 9th grade. Lagged effects of family were found in elementary school and significant lagged effects with supports from friends were found at 6th and 8th grade. The results of this study imply that the social support of family, friends, and teacher has an important role to encourage the self-esteem of multicultural adolescents.

• 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%).

• Education of Primary School Mathematics
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• v.23 no.4
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• pp.207-227
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• 2020

The demand for private education in Korea is steadily increasing every year, and the participation rate of private education is increasing as the grade goes down. In order to empirically verify the effectiveness of private education, it is necessary to analyze through longitudinal data that has been mainly investigated over a long period of time. This study investigated the longitudinal changes in mathematics academic achievement and participation time in mathematics private education using longitudinal data from 2013 (4th grade in elementary school) to 2017 (2nd grade in middle school) of the Seoul Education Longitudinal Study. The students were divided into groups in which mathematics academic achievement changed similarly as the grade went up, and the effect of mathematics academic achievement was examined according to the change of participation time in private mathematics education for each group. As a result of the study, it was found that the participation time of private math education of all students continuously increased from the 5th grade of elementary school to the 2nd grade of middle school, and the participation time of private math education by group was different. In addition, the effect of private tutoring by group was different according to the group.

• Communications of Mathematical Education
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• v.34 no.4
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• pp.525-544
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• 2020

There are many factors that affect academic achievement, and the influences of those factors are also complex. Since the factors that influence mathematics academic achievement are constantly changing and developing, longitudinal studies to predict and analyze the growth of learners are needed. This study uses longitudinal data from 2014 (second year of middle school) to 2017 (second year of high school) of the Seoul Education Longitudibal Study, and divides it into groups with similar longitudinal patterns of change in mathematics academic achievement. The longitudinal change patterns and direct influence of mood and satisfaction were examined. As a result of the study, it was found that the mathematics academic achievement of the first group (1456 students, 68.3%) including the majority of students and the second group (677 students) of the top 31.7% had a direct influence on the mathematics class attitude. It was found that the mood and satisfaction of mathematics classes did not have a direct effect. In addition, the influence of mathematics class attitude on mathematics academic achievement was different according to the group. In addition, students in group 2 with high academic achievement in mathematics showed higher mathematics class attitude, mood, and satisfaction. In addition, the attitude, atmosphere, and satisfaction of mathematics classes were found to change continuously from the second year of middle school to the second year of high school, and the extent of the change was small.