• The Korean Journal of Physiology and Pharmacology
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• v.15 no.1
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• pp.37-41
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• 2011

Interstitial cells of Cajal (ICC) evoke pacemaker activities in many tissues. The purpose of this study was to investigate the relationship between interstitial cell and pacemaker activity in the human ureter through the recording of spontaneous contractions. Spontaneous contractions of eight circular and longitudinal smooth muscle strips of the human ureter to acetylcholine (ACh) and/or norepinephrine (NE) were observed. Human ureteral strips were divided into proximal and distal groups, and each group was subdivided into circular and longitudinal groups. The proximal group showed spontaneous activities of 3~4 times within 5 minutes in the longitudinal group. ACh ($10^{-4}\;M$) augmented the frequency of the spontaneous contractions. The cumulative application of NE also augmented the frequency in a dose-dependent manner. The effects of NE application were inhibited by concomitant application of $10^{-5}\;M$ glibenclamide. Receptor tyrosine kinase (c-kit) staining revealed abundant ICCs only in proximal tissues. Therefore, spontaneous contractions of the human ureter might be modulated by ICC in the proximal region, and the actions might be related with the activation of cholinergic and/or adrenergic system mediated by a glibenclamide-sensitive pathway.

• Korean Journal of Child Studies
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• v.31 no.1
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• pp.65-82
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• 2010

This study investigated the longitudinal effects of family risk factors, parent-child relationships, and language abilities of children in low-income families in terms of both school adjustment and academic performance. The subjects were 176 children aged 5 to 7 and their mothers. They participated in follow up studies over the next 3 years. The children were tested using the Wechsler Intelligence Scales and language tests; and classroom teachers rated their levels of both school adjustment and academic performance. Mothers reported parent-child relationships, maternal depression, and family economic resources. Data were analyzed using Pearson's correlation, and structural equation modeling (SEM). Our results indicated that there were direct effects of language abilities, and indirect effects of parent-child relationships and maternal depression upon children's school adjustment and academic performance. It was also revealed that language abilities had a mediating effect between parent-child relationship and school adjustment/ academic performance.

• Journal of Welding and Joining
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• v.23 no.5
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• pp.20-24
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• 2005

Due to the difficulties associated with the supply of steel plates, hot rolled coil (Steel grade: SM490A) is considered fur structural materials in replace of the existing SWS50A-M1. However, it is found that SM490A exhibits a significant anisotropy in terms of impact energy with respect to transverse and longitudinal directions. In this study, an experimental investigation is carried out to examine the relationship between the anisotropy in impact values and the fatigue strengths of SM490A with respect to the rolling direction of test specimens. All test specimens failed around 1,500,000 cycles regardless of the test specimen direction. Therefore, it is found that the anisotropy in impact energy is not related to the fatigue strength of the materials considered in this study. However, the transverse direction specimen showed more rapid brittle fracture mode compared to that of longitudinal direction specimen, and this appears to be related to the lower impact values in transverse direction.

• Journal of the Korean Society of School Health
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• v.30 no.3
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• pp.274-283
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• 2017

Purpose: The purpose of this study was to investigate the mediating effects of self-esteem and self-resilience while identifying the relationship between bullying victimization (being bullied) and depression based on a longitudinal study design. Methods: Participants were adolescent cohort of 1,971 middle school students participating in 2013 and 2014 Korean Children and Youth Panel Survey conducted by National Youth Policy Institute. Data were analyzed by Pearson's Correlation and regression. Results: The major findings are as follows. First, self-esteem and self-resilience were positively related to each other and negatively related to depression and bullying victimization. Second, bullying victimization effected the level of depression of adolescents and self-esteem played a mediating role between bullying victimization and depression while self-resilience did not. Conclusion: The results suggest that emotional factors continue to play an important role in promoting psychological adjustment of victims of bullying. Therefore, interventions are more likely to be successful if they focus on emotional skills development of adolescents.

• Journal of Auto-vehicle Safety Association
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• v.13 no.1
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• pp.14-25
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• 2021

This paper presents a RLS based adaptive sliding mode observer (A-SMO) for unknown fault reconstruction in longitudinal autonomous driving. Securing the functional safety of autonomous vehicles from unexpected faults of sensors is essential for avoidance of fatal accidents. Because the magnitude and type of the faults cannot be known exactly, the RLS based A-SMO for unknown acceleration fault reconstruction has been designed with relationship function in this study. It is assumed that longitudinal acceleration of preceding vehicle can be obtained by using the V2V (Vehicle to Vehicle) communication. The kinematic model that represents relative relation between subject and preceding vehicles has been used for fault reconstruction. In order to reconstruct fault signal in acceleration, the magnitude of the injection term has been adjusted by adaptation rule designed based on MIT rule. The proposed A-SMO in this study was developed in Matlab/Simulink environment. Performance evaluation has been conducted using the commercial software (CarMaker) with car-following scenario and evaluation results show that maximum reconstruction error ratios exist within range of ±10%.

• The Korean Journal of Health Service Management
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• v.11 no.2
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• pp.93-103
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• 2017

Objectives : The aim of this study was to examine the effects of economic support on working women's depressive symptoms, using the dataset of the Korean Longitudinal Survey of Women and Family (KLoWF 4th). There were 2,055 subjects. Methods : A multiple regression model was used to study the association between two-income families and symptom of depression, controlling for socio-demographic characteristics, spouse relationship characteristics (couple activity, household labor, relationship with spouse). Results : Authors found a negative relationship between couple activity (b=-0.151, p<0.001) and depressive symptoms, a positive relationship between household labor (b=0.045, p=0.001) and depressive symptoms, and a negative relationship between relationship with spouse (b=-0.386, p<0.001) and depressive symptoms. Conclusions : The results of this study show the importance of spousal support in promoting the marital relationship and mental health among married working women.

• Journal of the Korean Home Economics Association
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• v.44 no.9
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• pp.89-101
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• 2006

The purpose of this study was to provide better understanding of longitudinal effects of early maternal employment on mother-child relationship using 1364 families participating the NICHD Study of Early Child Care in the U.S. Based on the information on maternal employment from 6 months after the child's birth, three employment groups were created: mothers who had always worked more than 30 hours per week, mother who had worked part-time or had been inconsistently employed, and mothers who had never worked. At 36 months, mothers who had extensively employed for the first 36 months showed significantly lower level of supportive presence compared to mothers who had never worked. Mothers who had partly employed for the first year of child's life displayed higher level of supportive presence at 36 months compared to mothers in the other two 12 month employment groups. No other significant employment group differences were found in the mothers' respect for child's autonomy and hostility at 36 months. At first grade, mothers in three employment groups were not different in their relationship with their child. The findings suggested that maternal employment, specifically early extensive maternal employment, does not consistently predict lower quality of mother-child interaction in two or three years later.

• Journal of Korean Home Economics Education Association
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• v.29 no.2
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• pp.67-84
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• 2017

This study investigated the influence of life satisfaction, accomplishment value, peer attachment, and relationship with teachers on the self-esteem of adolescents in three time points. The study population consisted of a nationally representative sample of middle school 1st grade students who completed the Korean Children and Youth Panel Survey(KCYPS) of the National Youth Policy Institute in 2010, 2012, and 2014. Descriptive statistics used included frequency, percentage, average, and standard deviation; in addition, reliability, repeated measure ANOVA, and regression results were reported using SPSS statistics. The results were as follows. First, this study showed that the longitudinal changes of self-esteem, life satisfaction, accomplishment value, peer attachment, and relationship with teachers were significantly different across three time points. Second, longitudinal changes in adolescents' self-esteem, life satisfaction, peer attachment, and relationship with teachers differed by gender, but accomplishment value did not. Third, life satisfaction was the most influential to self-esteem and peer attachment was the second most influential in the three data sets after controlling for gender, parents' academic attainment, and residential area. The influence of life satisfaction on self-esteem decreased across the three time points, but that of peer attachment increased over time. Instruction on life satisfaction and peer attachment needs to be more highlighted in Home Economics classes to enhance the self-esteem of adolescents.

• 한국노년학
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• v.29 no.2
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• pp.717-728
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• 2009

The purpose of this study is to examine the moderating effect of family relationship (relationship with spouse and adult children)about the impact of economical status and health(physical health, cognitive health) on depression. The data came from Korean Longitudinal Study of Ageing(KLoSA) 2005 of Korea labor institute. 2,566 individuals(male 1,535, female 1,031) with spouse and aged 65 and over were selected for this study. Using the multiple regression model, we found that significant effect of economical status, physical health and cognitive health on depression. Also relationship with spouse moderated the effect of economical status on depression and relationship with adult children moderated the effect of cognitive health on depression. The results of this study suggest that family relationship is important variable to reduce depression of the elderly.

• Educational Technology International
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• v.16 no.2
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• pp.111-140
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• 2015

Perceived control and use of Information and Communication Technology (ICT) has long been known as important aspects of students' achievement. The purpose of this study was to explore the relationship between adolescents' perceived achievement goals, their Individual ICT use, ICT use for government-sponsored educational programs on television or the Internet, academic achievement and the attitude toward learning. Most previous research has employed cross-sectional data analysis using relatively small samples. For this purpose, this study used the datasets of the Seoul Education Longitudinal Study (SELS 2011) from Seoul Educational Research & Information Institute. We analyzed structural equation modeling (SEM) a nationally represented sample (4,346 eighth-grade students). The results of this study showed that students' perceived achievement goals had a positive relationship with their individual ICT use, and their use of ICT programs for government-sponsored educational programs on television or the Internet. Also, students' individual ICT use had a positive relationship with their achievement, but ICT use for government-sponsored educational programs on television or the Internet did not have a significant relationship with their achievement. That is, students' individual ICT use mediated the relationship between their perceived goals and academic achievement. In addition, results indicated that students' individual ICT use and ICT use for government-sponsored educational programs on television or the Internet had a positive relationship with their attitude toward learning. That is, both students' individual ICT use and ICT use for government-sponsored educational programs on television or the Internet mediated the relationship between their perceived goals and their attitude toward learning.