• The Journal of Korean Association of Computer Education
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• v.20 no.3
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• pp.35-46
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• 2017

The purpose of this study is to analyse the longitudinal relations between creativity, academic achievements, and utilization of computer & smartphone of middle school students. For this purpose, multivariate latent growth model was verified, using three year longitudinal panel data of Seoul Educational Longitudinal Study(2013-2015). Results indicated that the more students in their first year used computer & smartphone, the better scores they obtained on the creativity and academic achievements. As their grade goes up, while the growth rates of using computer & smartphone and creativity were related positively, the growth rates of using computer & smartphone and academic achievements -even though it was not statistically significant- were related negatively. In addition, the first year students, who obtained high level of scores on the creativity, obtained high level of scores on academic achievements, but this tendency was not significant as their grade goes up.

• Archives of Plastic Surgery
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• v.45 no.5
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• pp.403-410
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• 2018

Background Radiation-induced skin injury is a dose-limiting complication of radiotherapy. To investigate this problem and to develop a framework for making decisions on treatment and dose prescription, a murine model of radiation-induced skin injury was developed. Methods The dorsal skin of the mice was isolated, and irradiation was applied at single doses of 15, 30, and 50 Gy. The mice were followed for 12 weeks with serial photography and laser Doppler analysis. Sequential skin biopsy samples were obtained and subjected to a histological analysis, immunostaining against transforming growth factor beta (TGF-${\beta}$), and Western blotting with Wnt-3 and ${\beta}$-catenin. Increases in the levels of TGF-${\beta}$, Wnt, and ${\beta}$-catenin were detected after irradiation. Results All tested radiation doses caused progressive dermal thickening and fibrosis. The cause of this process, however, may not be radiation alone, as the natural course of wound healing may elicit a similar response. The latent appearance of molecular and histological markers that induce fibrosis in the 15 Gy group without causing apparent gross skin injuries indicates that 15 Gy is an appropriate dose for characterizing the effects of chronic irradiation alone. Thus, this model best mimics the patterns of injury that occur in human subjects. Conclusions This animal model can be used to elucidate the gross and molecular changes that occur in radiation-induced skin injury and provides an effective platform for studying this adverse effect without complicating the process of wound healing.

• Journal of Korean Society of Transportation
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• v.24 no.6 s.92
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• pp.119-127
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• 2006

Recently. there are demanding a better sidewalk environment considering side of psychic as well as physical factors as the rapid growth of cities and improvement of traffic consciousness. Also. it needs to give a better sidewalk environment because those pedestrians evade a sidewalk space with minimum Physical design standards. So. we think very important that get a grip what makes Pedestrian feel a comfort and amenity in sidewalk above all. In this study, we carried out a cognition experiment of sidewalk environment on considering the human's psychic with Sensibility Ergonomics and the survey method using SD (Semantic Differential) scale. And we made a recognition evaluation model of sidewalk landscape and sensibility recognition model of sidewalk design factors using LISREL model that analysis sensibility recognition of sensibility adjective by SD scale. In results, we found out a possibility of the design with comfort and amenity in sidewalk environment as considering Sensibility Ergonomics, and an importance of harmonious green environment as a roadside tree etc. above all.

• Journal of Microbiology and Biotechnology
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• v.17 no.1
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• pp.146-153
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• 2007

A mathematical competition model between normal flora and an invading pathogen was devised to allow analysis of bacterial infections in a host. The normal flora includes the various microorganisms that live on or within the host and act as a primary human immune system. Despite the important role of the normal flora, no mathematical study has been undertaken on models of the interaction between it and invading pathogens against a background of antibiotic treatment. To quantify key elements of bacterial behavior in a host, pairs of nonlinear differential equations were used to describe three categories of human health conditions, namely, healthy, latent infection, and active infection. In addition, a cutoff value was proposed to represent the minimum population level required for survival. The recovery of normal flora after antibiotic treatment was also included in the simulation because of its relation to human health recovery. The significance of each simulation parameter for the bacterial growth model was investigated. The devised simulation showed that bacterial proliferation rate, carrying capacity, initial population levels, and competition intensity have a significant effect on bacterial behavior. Consequently, a model was established to describe competition between normal flora and an infiltrating pathogen. Unlike other population models, the recovery process described by the devised model can describe the human health recovery mechanism.

• 한국노년학
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• v.36 no.3
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• pp.541-562
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• 2016

The current study investigates the relationship and the mechanisms between bridge employment and change in marital satisfaction during midlife, using a three-wave panel dataset obtained from the Korean Baby Boomer Panel Study. A multivariate latent growth analysis reveals that the transition from career employment to bridge employment, compared to maintaining career employment, has an indirect negative effect on increase rate of marital satisfaction through the wage decrease. A steep decrease in wage following transition to bridge employment causes a lower increase in marital satisfaction. On the other hand, continuously engaging in bridge employment rather than career employment is associated with a higher increase in marital satisfaction via a higher increase in job commitment. This result implies that Baby Boomers adapt to bridge employment over time. Overall, the present study finds that the effect of bridge employment on the change in marital satisfaction during midlife varies with the duration of bridge employment. A future research needs to explore which factors can buffer the negative effect of decrease in wage during transition to the bridge employment on the change in marital satisfaction.

• Human Ecology Research
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• v.56 no.2
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• pp.157-165
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• 2018

Using data from the Panel Study on Korean Children, this study investigated whether children with high levels of problem behaviors adjusted more poorly on the $1^{st}-grade$ than children with low levels of problem behaviors, and whether there was evidence of intra-individual stability in behavior problems over time. Data were analyzed by use of the Latent Growth Model and group differences analyses. Three findings were noteworthy. First, there was evidence of intra-individual and inter-individual variability in behavior problems between poor- and non-poor household children. Second, children with higher initial levels of internalizing and externalizing behaviors at 4 years had lower school readiness scores at 6 years. Finally, children with lower levels of school readiness at 6 years had lower school adjustment scores in $1^{st}$ grade. The results discuss implications for future research and policies for preschool children. With mediating effect of school readiness, developmental trajectories of child's problem behavior have been found to be predictors of delayed achievements in school. The results show that intervention programs are necessary for children with high levels of problem behavior. This study also showed that children who experienced poverty at home could have more difficulties in school readiness and school adjustment.

• 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.

• Journal of the Korea Society of Computer and Information
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• v.25 no.9
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• pp.159-166
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• 2020

The purpose of this research is to suggest some practical and policy implications for improving adolescent's self-esteem through analyzing longitudinally the effects of parental attitude, peer relationship, student-teacher relationship, school learning activity, life-goal on adolescent's self-esteem by using latent growth curve model. Analytical data was obtained from the KYCPS. The analytical results showed that the change model of adolescent's self_esteem turned out to be a leaner model in which the change rate and intercept were significant. Second, time dependent variables influence on adolescent's self_ esteem meaningfully. Third, time dependent variables influence on adolescent's self_ esteem changes significantly. This study proposed some policy implications basing on these findings.

• Journal of Family Relations
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• v.21 no.2
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• pp.77-96
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• 2016

Objectives: The aims of this study are to examine the associations between marital satisfaction and life satisfaction among Korean retirees in later life and to test whether the degrees of associations increased over time. Method: Nationally representative Korean Longitudinal Study of Ageing data from wave 1 (in 2006) to wave 4 (in 2012) was utilized and retirees in later life (65-89 years old, N=402) were analyzed. Latent growth modeling (LGM) and model constraint were applied using Mplus 7.3. Age, sex, household income, subjective health, depressive symptoms and elapsed time after retirement were included as control variables. Results: Linear unconditional LGM fitted the data well and showed gradual decrease in life satisfaction. Conditional LGM revealed significant associations between marital satisfaction and life satisfaction from time 1 to time 4. According to model constraint test, the size of associations between marital satisfaction and life satisfaction did not change with time. Conclusions: To sum up these results, the associations between marital satisfaction and life satisfaction were significant and relatively stable over time among retirees in later life. This study suggests one's spouse is a fundamental component of social convoy among Korean retirees in later life. Therefore, intervention programs targeted toward enhancing marital relationships among retirees' couples will help them to live a better life.

• 한국노년학
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• v.39 no.3
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• pp.467-484
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• 2019

The purpose of this study is to explore latent classes of longitudinal medical expenses of older people and to analyze its predictors and its effects on subjective health. Among participants of the Korean Health Panel, the sample of this study includes 1,119 people who is 65-year-old or older and reported their medical expenses for nine consecutive years. The analyses were conducted in three steps. First, Growth Mixture Model (GMM) was applied to find distinct subgroups showing similar patterns in medical expenses. The results showed four groups which were classified as high medical expenditure maintenance group, medical expenditure increase group, low medical expenditure maintenance group, and medical expenditure reduction group. Second, the multinominal logistic regression found that the presence of spouse, economic participation, the number of chronic diseases, and the type of health insurance were significant predictors of latent classes in medical expenses. In particular, the greater the number of chronic diseases, the higher the likelihood of belonging to the high medical expenditure maintenance group. In addition, medical benefit recipients are more likely to belong to the low medical cost maintenance and medical cost reduction groups. Third, multiple regression analysis revealed that the older people in the groups with low or reducing expenses reported better subjective health than people with higher expenses. This study has its meanings in exploring the heterogeneity in longitudinal medical expenses among older people and its predictors and its associations with health outcome. The results of this research provide background information in establishing public health policy for older people.