• Survey Research
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• v.18 no.4
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• pp.25-59
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• 2017

The current study investigated how elderly husbands and wives' marital satisfaction and depression change over time and examined how changes in marital satisfaction account for changes in depression between and within the dyads. The longitudinal dyadic data from the first wave(2006) to the fifth wave(2014) of the Korean Longitudinal Study of Aging(KLoSA), collected by the Korea Employment Information Service, were used for the analyses. Because husbands and wives are interdependent within couples, we applied statistical models for dyadic data. The dyadic growth model(DGM) was used to model the trajectories of marital satisfaction and depressive symptoms. In order to analyze the association of these growth factors, we proposed the dyadic growth actor-partner interdependence model(DG-APIM) and applied the model to the data. The results showed that on average the husbands' marital satisfaction was higher but decreased faster over the course of the study than the wives'. It also showed that the average depression of the husbands was lower than that of the wives but the husbands' depression increased faster than the wives' over the course of the study. The variance of the averages of husbands' (wives's) depression was accounted for by that of wives'(husbands') marital satisfaction, showing a partner effect. The variance of the slopes of husbands'(wives') depression was accounted for by that of marital satisfaction of themselves, showing an actor effect. The results showed that there is a longitudinal interdependence between husbands and wives' marital satisfaction and depression and supported the marital discord model of depression.

• Journal of Korean Society of Disaster and Security
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• v.8 no.1
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• pp.29-37
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• 2015

This study is concerned with the estimation of fluctuation wind velocity spectrum and turbulence characteristics in the major cities reflecting the recent meteorological with typhoon wind velocity about 2003 (Maemi) 2010 (Kompasu) 2012 (Tembin). The purpose of this paper is to present spectral analysis for longitudinal component fluctuating velocity. In the processes of analysis, the longitudinal velocity spectrums are compared widely used spectrum models with horizontal wind velocity observations data obtained at Korea Meteorological Adminstration (KMA) and properties of the atmospheric air for typhoon fluctuating wind data are estimated to parameters with turbulency intensity, shear velocity and roughness length.

• The Korean Journal of Applied Statistics
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• v.30 no.1
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• pp.103-117
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• 2017

In longitudinal data analysis, the serial correlation of repeated outcomes must be taken into account using covariance matrix. Modeling of the covariance matrix is important to estimate the effect of covariates properly. However, It is challenging because there are many parameters in the matrix and the estimated covariance matrix should be positive definite. To overcome the restrictions, several Cholesky decomposition approaches for the covariance matrix were proposed: modified autoregressive (AR), moving average (MA), ARMA Cholesky decompositions. In this paper we review them and compare the performance of the approaches using simulation studies.

• Journal of the Korean Society of School Health
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• v.34 no.3
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• pp.151-160
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• 2021

Purpose: The purpose of this study was to identify predictors of suicidal attempts in adolescents over 5 years after school dropout. Methods: The data of the Panel Survey of School Dropouts (of 2013 to 2017) conducted by the National Youth Policy Institute were analyzed. The analysis used the 2013 survey data as the baseline and examined suicidal attempts from 2013 to 2017. A total of 776 adolescents were included in the analysis. Descriptive statistics, 𝝌² test, t-test, and multiple logistic regression were carried out using SAS 9.2. Results: About 11% (87 out of 776) of the adolescents with an experience of dropout attempted suicide between 2013 and 2017. The risk of suicidal attempts was significantly lower in female (AOR: 0.57, 95% CI: 0.87~0.93) than in male adolescents. The higher the self-esteem, the lower the risk of suicidal attempts (AOR: 0.87. 95% CI: 0.78~0.97). The higher the depression level (AOR: 1.10, 95% CI: 1.05~1.16) and the rate of parental abuse (AOR: 1.09, 95% CI: 1.02~1.18), the higher the risk of suicidal attempts. Conclusion: The findings of the study suggest that those who are male, depressed, have low self-esteem or have been abused by their parents are at high risk of suicidal attempts among the adolescents with dropout experiences. Therefore, early intervention is necessary for those at high risk.

• Education of Primary School Mathematics
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• v.24 no.3
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• pp.135-156
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• 2021

Achievement pressure and enthusiasm affecting mathematics academic achievement are constantly changing and affecting academic achievement. Therefore, a longitudinal study is needed to examine the influence of the change patterns of teachers' achievement pressure and enthusiasm on the change patterns of academic achievement. This study utilized student data from the 5th grade of elementary school (2013 year) to the third grade of middle school (2017 year) of the Korean Education Longitudinal Study 2013. The longitudinal change patterns of mathematics academic achievement were classified into similar subgroups and the influence of the longitudinal change patterns of the achievement pressure and enthusiasm of each group on the longitudinal change pattern of mathematics academic achievement and the path were compared and analyzed. As a result of the analysis, in all four subgroups with similar longitudinal changes in mathematics academic achievement, the teacher's achievement pressure showed little change from the fifth grade, while the teacher's enthusiasm continued to decline from the fifth grade. In addition, the influence of teachers' achievement pressure and enthusiasm perceived by students in each group on mathematics academic achievement was different. This suggests that in order to improve mathematics academic achievement, it is necessary to support teaching and learning reflecting the characteristics and dispositions of students.

• Structural Engineering and Mechanics
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• v.69 no.2
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• pp.193-204
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• 2019

This paper presents results from experimental and numerical studies on the response of steel-concrete composite box bridge girders under certain localized fire exposure conditions. Two composite box bridge girders, a simply supported girder and a continuous girder respectively, were tested under simultaneous loading and fire exposure. The simply supported girder was exposed to fire over 40% of its span length in the middle zone, and the two-span continuous girder was exposed to fire over 38% of its length of the first span and full length of the second span. A measurement method based on comparative rate of deflection was provided to predict the failure time in the hogging moment zone of continuous composite box bridge girders under certain localized fire exposure condition. Parameters including transverse and longitudinal stiffeners and fire scenarios were introduced to investigate fire resistance of the composite box bridge girders. Test results show that failure of the simply supported girder is governed by the deflection limit state, whereas failure of the continuous girder occurs through bending buckling of the web and bottom slab in the hogging moment zone. Deflection based criterion may not be reliable in evaluating failure of continuous composite box bridge girder under certain fire exposure condition. The fire resistance (failure time) of the continuous girder is higher than that of the simply supported girder. Data from fire tests is successfully utilized to validate a finite element based numerical model for further investigating the response of composite box bridge girders exposed to localized fire. Results from numerical analysis show that fire resistance of composite box bridge girders can be highly influenced by the spacing of longitudinal stiffeners and fire severity. The continuous composite box bridge girder with closer longitudinal stiffeners has better fire resistance than the simply composite box bridge girder. It is concluded that the fire resistance of continuous composite box bridge girders can be significantly enhanced by preventing the hogging moment zone from exposure to fire. Longitudinal stiffeners with closer spacing can enhance fire resistance of composite box bridge girders. The increase of transverse stiffeners has no significant effect on fire resistance of composite box bridge girders.

• The Journal of the Korea Contents Association
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• v.22 no.9
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• pp.473-484
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• 2022

This study aimed to verify the reciprocal casual relationship between self-rated health status and depression in the elderly through longitudinal analysis. An autoregressive cross-lagged model was identified. This study analyzed 3,363 elderly people aged 65 or older using the 5th, 6th, and 7th wave data from Korean Longitudinal Study of Ageing(KLoSA). The results are as follows. First, self-rated health status had a positive(+) autoregressive effect. Second, depression had a positive(+) autoregressive effect. Third, self-rated health status had a negative(-) cross-lagged effect on depression, but depression was not a casual predictor of self-rated health status. Based on these findings, it was suggested that there is a need for systematic policies to improve basic fitness in the early stages of old age, as well as the need to expand health promotion programs and implement integrated depression management programs.

• Korean Journal of Childcare and Education
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• v.11 no.1
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• pp.289-303
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• 2015

The aim of this study was to examine the short-term longitudinal effect of creativity-fostering programs for pre-early childhood teachers on their problem solving ability and self-efficacy. The participants of this study were 67 pre-early childhood teachers (36 from the experimental group and 31 from the control group) in Seoul, Kyunggi-do, and Chungcheong-do, Korea. Pre-early childhood teachers' problem solving ability and self-efficacy was measured three times. Data were analyzed with a $2{\times}3$ ($group{\times}test$) two-way analysis of variance for repeated measures. The change in problem solving and self-efficacy appeared to be dependent on the group and test. Further statistical analysis of the data indicated that the participation of creativity-fostering programs for pre-early childhood teachers was longitudinally effective on their problem solving ability and self-efficacy.

• Journal of Preventive Medicine and Public Health
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• v.42 no.1
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• pp.59-66
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• 2009

Objectives : This study was performed using a longitudinal approach to explore the predictors for current smoking among male high school students. Methods : Baseline data was collected in May 2004 through a self-administrated questionnaire completed by 607 male students in a technical high school in Daegu city, Korea. Subsequently, their smoking behaviors were followed one year after. Among the 544 followed participants, data for 439 non-smokers in the first year was used in longitudinal analysis. Current smokers were defined as those respondents who had smoked one or more cigarettes within the 30 days preceding the survey. Several potential predictors for smoking were investigated including smoking history(never, experimental, former smoker), sociodemographic factors, environmental factors, attitudes toward smoking, and behavioral factors. Logistic regression was used to predict smoking with SPSS ver. 12.0. Results : According to multiple logistic regression analysis, those students who were more likely to smoke after one year were former smokers(OR: 2.12, 95% CI=1.01-4.44), current drinkers(OR: 2.55, 95% CI=1.33-4.89), who had four or five smokers among five best friends(OR: 3.43. 95% CI=1.14-10.30). In addition, those who had smokers among family members besides parents or siblings(OR: 1.66, 95% CI=0.92-2.98), exhibited a high level of subjective stress(OR: 1.77, 95% CI=0.96-3.26), or had a very good relationship with friends(OR: 1.93, 95% CI=0.99-3.75) were also more likely to smoke albeit with marginal statistical significance(p<0.1). Conclusions : A smoking prevention program aimed at high school students may be more effective with due consideration of the predictors highlighted in this study. However, further studies with larger sample size and various target populations are necessary to find potential predictors not found in this study but suggested in other longitudinal studies.

• Journal of the Korean Society of Safety
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• v.21 no.4 s.76
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• pp.95-101
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• 2006

It is well known that the thermal load in PSC(prestressed concrete) box-girder bridge is the principal cause of detrimental crack. The longitudinal stress caused by the lateral stress from the temperature gradient in slab of PSC box-girder bridge has a considerable influence on the durability and economy of bridge structures. As the basic study for the rational consideration of thermal load and the derivation of design guide, the inverse thermal analysis program for PSC box-girder bridges using field measurement data is developed. In this paper, thermal analyses are performed using field monitoring data for the sample PSC box-girder bridge. It is proposed that the link between monitoring program and the inverse analysis program is available.