• Steel and Composite Structures
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• 제6권3호
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• pp.237-255
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• 2006

This paper presents a novel analytical formulation for the analysis of composite beams with partial shear interaction stiffened by a bolted longitudinal plate accounting for time effects, such as creep and shrinkage. The model is derived by means of the principle of virtual work using a displacement-based formulation. The particularity of this approach is that the partial interaction behaviour is assumed to exist between the top slab and the joist as well as between the joist and the bolted longitudinal stiffening plate, therefore leading to a three-layered structural representation. For this purpose, a novel finite element is derived and presented. Its accuracy is validated based on short-and long-term analyses for the particular cases of full shear interaction and partial shear interaction of two layers for which solutions in closed form are available in the literature. A parametric study is carried out considering different stiffening arrangements to investigate the influence on the short-and long-term behaviour of the composite beam of the shear connection stiffness between the concrete slab and the steel joist, the stiffness of the plate-to-beam connection, the properties of the longitudinal plate and the concrete properties. The values of the deflection obtained from the finite element simulations are compared against those calculated using the effective flexural rigidity in accordance with EC5 guidelines for the behaviour of elastic multi-layered beams with flexible connection and it is shown how the latter well predicts the structural response. The proposed numerical examples highlight the ease of use of the proposed approach in determining the effectiveness of different retrofitting solutions at service conditions.

• 아동학회지
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• 제36권5호
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• pp.75-94
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• 2015

This study examined short-term longitudinal reciprocal relationships between maternal parenting behavior and preschoolers' compliance/noncompliance, as well as stability in both maternal parenting behavior and preschoolers' compliance/noncompliance over time. The sample which was used for this study was taken from a two-wave (one year apart) longitudinal study of preschool-aged children and their mothers (N = 53 dyads). At both times, mothers and their children were invited to a laboratory and engaged in 25 minutes of play involving three episodes of mother-child interaction. Maternal parenting behavior and preschoolers' compliance/noncompliance during play were coded using the Dyadic Parent-Child Interaction Coding System-III (DPICS-III). Maternal codes included positive, neutral, and negative parenting behaviors and child codes were comprised of compliance and noncompliance. The results revealed that during the play session, maternal neutral and negative parenting behavior and preschoolers' compliance were stable over time. In addition, T1 maternal negative parenting behavior was significantly related to T2 child compliance/noncompliance. However, T1 child compliance/noncompliance were not significantly associated with T2 maternal parenting behavior. These findings suggest that during the preschool period, there are unidirectional effects from mothers to children.

• 아동학회지
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• 제29권6호
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• pp.73-86
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• 2008

The purpose of this study was to investigate the effects of learning-related skills in kindergarten on school adjustment in first-grade children. Subjects were 119 kindergarten children. Instruments were Learning-Related Skill (Park, 2008) and School Adjustment (Chi & Jung, 2006). Statistical methods were Pearson product moment correlation coefficients and multiple regressions. Results of this study showed that : (1) there were positive relationships between learning-related skill in kindergarten and school adjustment in first-grade children. (2) Cognitive, behavioral, and affective learning-related skills in kindergarten were significant predictors of school adjustment in elementary school Conclusions suggest the importance of learning-related skills in kindergarten.

• 대한가정학회지
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• 제49권9호
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• pp.59-72
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• 2011

This study examined whether there are underlying latent classes of growth trajectories of maternal depression in the Korean population. Data from the first phase of the Panel Study of Korean Children (PSKC) of the Institute of Child Care and Education (KICCE) were used for this study. The final sample of participants included 1,471 mothers, who completed three interviews: at birth, at one month, and at four months. A two-class model consisting of depression (12.3%) and non-depression (87.7%) was considered the best-fitting solution using Mplus 3.13. The changes in postnatal depression in the Korean population within four weeks after childbirth, which is the period of "postpartum onset", seem to be important. Logistic regression analysis showed that duration of breast-feeding and planned pregnancy effects were significantly associated with trajectory class membership.

• 한국보육지원학회지
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• 제12권3호
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• pp.1-19
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• 2016

The purpose of this study was to examine the effect of parenting efficacy measured at 6 months of infancy, and on parenting stress at 9-months of infancy through a short-term longitudinal approach. Participants were 116 couples living in Seoul and Gyeonggi-do, whose first born children were in infancy. The results of the 116 couples were analyzed through the APIM analysis method. The results of the APIM showed that mothers' and fathers' actor effect was significant, which meant that parenting efficacy at 6 months of infancy could predict the existence of parenting stress at 9 months of infancy. However, the partner effect of both mothers and fathers was insignificant. This research demonstrates the significance of parenting efficacy at early infancy, which in turn affects parenting stress as well as factors that need to be considered in pre-parental education.

• 한국융합학회논문지
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• 제11권5호
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• pp.281-288
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• 2020

본 연구의 목적은 유아의 스마트기기 몰입경향성에 미치는 어머니 스마트기기 과의존의 영향과 반응성의 매개효과를 단기종단적으로 검증하는 데 있었다. 이를 위하여 3-5세 유아-어머니 144쌍(남아 73명, 여아 71명)을 대상으로 시점 1에서 어머니의 스마트기기 과의존과 유아의 스마트기기 몰입경향성, 6개월 후인 시점 2에서 유아의 몰입경향성과 모-아 상호작용 동안 양육자 반응성을 측정하였다. 이때 스마트기기에 대한 어머니의 과의존과 유아의 몰입경향성은 어머니 보고를 통해, 양육자 반응성은 모-아 상호작용 녹화 자료에 대한 관찰자 코딩을 통해 수집하였다. 경로분석을 통해 분석한 결과, 시점 1에서의 유아의 몰입경향성을 통제했을 때, 시점 1에서의 어머니의 과의존 경향성은 시점 2에서의 양육자 반응성을 매개로 시점 2의 유아의 스마트기기 몰입경향성을 간접적으로 유의하게 예측하였을 뿐만 아니라 직접적으로 예측하였다. 본 연구의 의의는 양육자의 스마트기기 사용 특성이 유아의 스마트기기 몰입경향성에 미치는 영향을 종단적 측면에서 실증적으로 살펴보았다는 점에서 찾을 수 있다.

• 한국보육지원학회지
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• 제15권6호
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• pp.59-75
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• 2019

Objective: The purpose of the present study was to examine the changes in the body perception of young children using a short-term longitudinal design, then to investigate the factors related to their body perception. Methods: Participants were 65 preschool children and their mothers that were recruited from five institutions. An 11-month, two-time point longitudinal design was used in which children were interviewed individually to examine the changes in body perception. At the second time point, children were assessed with an additional measure to investigate self-esteem, and their mothers also reported on maternal factors and children's media experience through a questionnaire. Data were analyzed by paired t-test, independent t-test, correlations and ANOVA. Results: The results showed a significant decline of children's negative body perception over time. Children's media experience was positively correlated with negative body perception. Mothers whose children showed higher body mass index (BMI) sent more verbal messages about their child's weight reduction. In addition, children's negative body perception was positively correlated with physical self-esteem. Finally, there was a significant difference in only the physical self-esteem according to the level of children's body perception. Conclusion/Implications: The findings would suggest theoretical and practical implications to support intervention and education programs to improve the body image of young children.

• 가정과삶의질연구
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• 제21권3호
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• pp.29-38
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• 2003

A three-year longitudinal design was employed to ascertain whether different types of behavioral inhibition(i.e. traditional, peer-social) were stable from toddler to preschool age(2-4 year), and whether inhibited temperament and/or parenting style would independently and interactively predict children's subsequent social and behavioral outcomes. At time 1, 113 toddlers (55 males, 58 females) and their mothers were observed in the traditional inhibition paradigm. At time 2, 36 4-year-old children were observed with unfamiliar peers in the nontraditional inhibition paradigm. Maternal ratings of psychological functioning of children and maternal behaviors were also obtained for both time 1 and 2. Results showed that behavioral inhibition was not stable from toddler to preschool age. Maternal authoritative behaviors at age 2 were negatively associated with preschooler's social reticence. Toddler's behavioral inhibition was negatively associated with maternal authoritative behaviors at age 4. In a cross-lag correlation analysis, maternal authoritative behaviors appeared to affect child's behavioral inhibition more strongly than the other way around.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.73-76
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• 2004

The short piers of bridge which is constructed by cantilever method may not be flexible enough to accommodate longitudinal movement of box girders. The constraint effects of longitudinal movement of box girders can introduce large stresses, and consequently large moments into short piers. This study is aimed at proposing a method to reduce moment of short piers in bridge constructed by cantilever method. Numerical analyses are carried out depending on the parameters such as control force and height of piers. Numerical results of the study represent that long-term moment of piers can be controlled effectively by employing the proposed method.

• 한국보육지원학회지
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• 제16권1호
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• pp.115-143
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• 2020

Objective: The purpose of this study was to examine underlying types of developmental trajectories of adaptation to child care among infants and toddlers. This study also aimed to identify latent classes in their child care adaptation types in order to find predictors that account for individual differences. Methods: Participants were 420 mothers of infants and toddlers and 123 teachers. The levels of child care adaptation of participating infants and toddlers were rated monthly from early April to June, 2019. The collected data were analyzed using growth mixture modeling, latent class analysis and multinominal logistic analysis. Results: The results of growth trajectories of child care adaptation showed there were two to four latent groups by dimension of child care adaptation. Also, the groups of individual dimensions of child care adaptation were classified into three latent classes, which were 'complying and positive group', 'negative group', and 'individualized group. Multinominal logistic analysis revealed that children's age, gender, and temperament differentiated the three latent classes of adaptation to child care. Conclusion/Implications: The results show individual characteristics that infants and toddlers possess should be prudently considered in order for successful adaptation to child care.