• Korean Journal of Human Ecology
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• v.6 no.2
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• pp.27-36
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• 1997

The purpose of this study was to investigate the relationship between percieved parenting by high school students and drinking, smoking and substance use of adolescents. The subject were 257 adolescents of 2nd grade from high school in Taejon (male 126, female 131). The questionnaires consist of 37 items. It was used for adolescents. The respondents were asked complete the self reported questionnaire and the data were analyzed with reliability, frequencies, percentage, means, standard deviation, Pearson correlation coefficient and t-test. The major findings are as follows. 1. Forty-six percent of the boys and 19 percent of the girls have been drinking, 15.8 percent of boys 1.5 percent of girls have been smoking, substance use were 1.6 percent of all. 2. Boys did more drinking, smoking and substance use than girls did. 3. Adolescent's drinking, smoking and substance use behavior were associated with controlled and rejected parenting perceived by adolescents. 4. Parent's socio economic status was not associated with adolescent's problem behavior.

• Korean Journal of Childcare and Education
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• v.11 no.6
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• pp.133-151
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• 2015

The aim of this study was to examine how children's self control, mother's addiction to smart devices and parenting behavior influence the way young children used smart devices. Participants were made up of 166 preschoolers and their mothers. Descriptive analysis, Pearson's correlation coefficient, and hierarchical regression analysis were used for statistical analysis. The results were as follows: First, children in their early childhood years used smart devices once or twice a week, for ten to thirty minutes, mainly during weekends. Children in their early childhood stage started to use smart devices before reaching the age of 3, and accessed them through their parents, usually along with their siblings. Parents allowed their children to use smart devices for fun and entertainment, with only 66.3% of them setting rules. Second, the mother's tendency to be immersed in smart devices, overprotection and permission were positively correlated to young children's overusage of smart devices, whereas geniality, encouragement, setting limits, and children's self control were negatively correlated. The study also found that the mother's tendency of being immersed in smart devices was the most influential factor for their children's overusage of smart devices. The value of this study lies in providing practical suggestions for children's smart device usage and parental education programs.

• Journal of Digital Convergence
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• v.16 no.3
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• pp.395-405
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• 2018

The purpose of this study is to investigate the effects of parental rearing attitudes on smartphone addiction and mediation effect of children's aggression and impulse between them. The randomly chosen 390 subjects of the 4th and 5th elementary school students (boy: 199, girl: 191) of J City participated in this research. The main scales were EMBU-Shot, Smartphone Addiction Scale and NEO-PAS. Spss 22.0 was used for its statistical analysis, that is correlation analysis and regression analysis. The main results are as follows. First, parental rearing attitude, smartphone addiction, and aggression and impulse were statistically significantly correlated. Second, it is testified that rejective parental rearing attitudes statistically significantly increasingly influenced smartphone addiction with partial mediation of aggression and impulse. Also overprotective parental rearing attitudes statistically significantly increasingly influenced smartphone addiction with full mediation of them. It suggested the importance of intervention for aggression and impulse of the children with smartphone addiction as well as parental rearing attitude changes in intervening and counseling them. This study tried to supply evidence-based and basic data for the developing preventive education and counseling programs for them. The limit and future tasks were discussed.

• Journal of the Korea Concrete Institute
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• v.21 no.6
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• pp.763-771
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• 2009

As the demand on long span structures increases more in recent years, the excessive deflection, in addition to the ultimate strength, in horizontal members becomes a very important issue. For this reason, as an alternative method to effectively solve the deflection problems, the application of post-tensioned structural system with unbonded tendon increases gradually. However, most of the existing researches on post-tensioned members with unbonded tendons (UPT) focused on the ultimate flexural strength, which would be impossible or improper to check serviceability such as deflections. Therefore, this study aims at proposing a stress prediction model for unbonded tendons that is applicable to the behavior of UPT members from the very initial loading stages, post-cracking states, and service to ultimate conditions. The applicability and accuracy of the proposed model were also evaluated comparing to the existing test results from literature. Based on such comparison results, it was verified that the proposed model provided very good predictions on tendon stresses of UPT members at various loading stages regardless their different characteristics; wide range of reinforcement index, different loading patterns, and etc. The proposed model especially well considered the effect of various loading types on stress increases of unbonded tendons, and it was also very suitable to apply on the over-reinforced members that easily happened during strengthening/repairing work.

• Journal of the Korea Concrete Institute
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• v.21 no.4
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• pp.489-499
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• 2009

It is quite difficult to predict the flexural strength of post-tensioned members with unbonded tendons (unbonded posttensioned members, UPT members) because of debonding behavior between concrete and prestressing tendons, which is different from that with bonded tendons. Despite many previous researches, our understanding on the flexural strength of UPT members is still insufficient, and thus, national codes use different methods to calculate the strength, which quite often give very different results. Therefore, this paper reviews various existing methods, and aims at proposing an improved rational strength model for UPT flexural members having better accuracy. Additionally, a database containing a large number of test data on UPT flexural members has been established and used for verification of the proposed flexural strength model. The analysis results show that the proposed method provides much better accuracy than many existing methods including the rigid-body model that utilizes the assumption of concentrated deformation and plastic hinge length, and that it also gives proper consideration on the effects of primary parameters such as reinforcement ratio, loading pattern, concrete strength, etc. Especially, the proposed method also well predicts the ultimate stress of unbonded tendons of over-reinforced members, which are often possible in construction fields, and high strength concrete members.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.699-707
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• 2019

The present study was designed to examine how much Korean elementary school children used the YouTube, and tested whether the overuse of YouTube might be related to adjustment problems such as low parental warmth, low self-esteem, and low school satisfaction. Two hundred and thirty-eight elementary school students answered a questionnaire enquiring about their YouTube use, parental practice, self-esteem, and school satisfaction. Results indicated that more than half of the participants watched the YouTube at least one hour per day, and 15.6% of them watched the YouTube more than 3 hours per day. Negative relationships between YouTube watching time and parental warmth, self-esteem, and school satisfaction were found. YouTube watching time also partially mediated between parental warmth and adjustment problems. Parental rejection and overprotection were not related to children's YouTube watching time. These study results can be used as seminal data for developing children's YouTube watching guidelines.

• Korean Journal of Food Science and Technology
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• v.50 no.2
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• pp.238-243
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• 2018

This study aimed to compare total phenolic, total flavonoid, and vitamin C contents, antioxidant capacities, and sensory characteristics of jangachi made from green kiwifruit (Actinidia deliciosa cv. Hayward) and golden kiwifruit (A. chinensis cv. Hort16A), which were cured with doenjang and kochujang. Golden kiwifruit had higher total phenolic, total flavonoid, and vitamin C contents, and antioxidant capacities than green kiwifruit. Jangachi of both cultivars of kiwifruit had generally higher total phenolic and flavonoid contents, and antioxidant capacities than fresh kiwifruit. Doenjang jangachi of kiwifruit had higher total phenolic contents and antioxidant capacities than kochujang jangachi. Jangachi made from golden kiwifruit cured with kochujang, following pretreatment with sugar solution, had the highest overall quality on sensory evaluation among jangachies tested herein. Together, our findings suggest that kiwifruit jangachi may serve as a good dietary source of phenolics and antioxidants.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.5 no.1
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• pp.172-183
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• 1994

The present study investigated the relationship between parental problem drinking and risk for malajustment in adolescents. A group of adolescent children of problem drinkers(126 boys, 210 girls) and a group of children of non-problem drinkers(190 boys, 222 girls) were compared on demographic variables, perceived relationships with parents(parental care and parental over-protection), depression, anxiety, alcohol expectancies, alcohol involvement and self-reported delinquency. Adolescent children of problem drinkers reported lower level of perceived parental care and higher level of perceived parental overprotection compared to the children of nonproblem drinkers. They also reported higher depression, anxiety and alcohol expectancies, as well as more alcohol involvement and delinquent behaviors. Multiple regression analyses were performed seperately for male and female adolescents with depression, anxiety, alcohol expectancies, alcohol involvement and self-reported delinquency as outcome variables. Adolescents' emotional distress(depression and anxiety) was associated with perceived relationships with parents rather than parental problem drinking, but adolescents' alcohol problems and delinquency were associated with parental problem drinking and adolescents' emotional distress rather than their perceived relationships with parents.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.313-316
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• 2008

Corrosion of steel in the reinforced concrete structures is one of the main reason of degradation. It causes that lifetime of structures is shortened and maintenance cost is increased. And it also causes degradation of structures like bridges which are under repeated load. So, many research have been performed about FRP rebar. But there are few research about FRP rebar under fatigue. This study is to examine flexural characteristic of concrete beam reinforced with FRP(CFRP, GFRP) rebar under static and fatigue for considering the application. The specimens that used in this study are designed by ACI 440.1R-06 and reinforced with CFRP(CR) or GFRP(GR) overly. In the result of static bending test, all specimens were failed at compression phase. In fatigue test, the fatigue stress level was 60%, 70% or 80% of the static bending strength. Most of the specimens seemed to be compressive failure, but CR-60 and CR-70 specimens were failed with rupturing of tension bar.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.3 s.49
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• pp.47-55
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• 2006

Seismic performance and retrofit of reinforced concrete (RC) two-column piers widely used at roadway bridges in Korea was experimentally evaluated. Ten two-column piers that were 400 mm in diameter and 2,000 mm in height were constructed. These piers were subjected to hi-directional cyclic loadings under a constant axial load of $0.1f_{ck}A_g$. Test parameters were the confinement steel ratio, loading pattern, lap splice of longitudinal reinforcing bars, and retrofitting method. Specimens with lap-spliced longitudinal bars were retrofitted with steel jacket, pre-stressing steel wire, and steel band. Test result showed that while the specimens subjected to bi-directional lateral cyclic loadings which consisted of two main amplitudes in the transverse axis and two sub amplitudes in longitudinal axis, referred to as a T-series cyclic loadings, exhibited plastic hinges both at the top and bottom parts of the column, the specimens subjected to bi-directional lateral cyclic loadings in an opposite way, referred to as a L-series cyclic loadings, exhibited a plastic hinge only at the bottom of the column. The displacement ductility of the specimen under the T-series loadings was bigger than that of the specimen under the L-series loadings. Specimen retrofitted with pre-stressing steel wires exhibited poor ductility due to the upward shift of the plastic hinge region because of over-reinforcement, but specimens retrofitted with steel jacket and steel band showed the required displacement ductility. Steel band can be an effective retrofitting scheme to improve the seimsic performance of RC bridge piers, considering its practical construction.