• The Korean Journal of Ecology
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• v.20 no.2
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• pp.83-94
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• 1997

Stomatal closing by ozone and water stress could reduce further ozone injury by inhibition of ozone influx to the tissue. Direct effect of ozone on stomata can be explained from two aspects which are a stimulation of stomatal closing and an inhibition of stomatal opening. An increase of $Ca^{2+}$ influx into cytoplasm by ozone could stimulate potassium efflux ion channel and inhibits inward potassium ion channels. By this mechanism ozone could induce stomatal closing. On the other hand, ozone could inhibit stomatal opening by affecting the activity of $H^{+}$ dependent ATPase of the membrane in guard cells. This would inhibit proton efflux which precede stomatal opening. It is also possible that ozone could reduce the activity of photosynthesis in guard cells which lead to affect the production of osmotically active sugars and energy. Indirect effect of ozone to stomata is through the effect of $CO_2$ elevation as a result of damage of the photozynthetic machinery. This indirect effect is slower than the direct effect.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.1
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• pp.22-30
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• 2008

This paper deals with the nonlinear optimal control approach to helicopter maneuver problems using the indirect method. We apply a penalty function to the deviation from a prescribed trajectory to convert the system optimality to an unconstrained optimal control problem. The resultant two-point boundary value problem has been solved by using the multiple-shooting method. This paper focuses on the effect of the number of shooting nodes and initialization methods on the numerical solution in order to define the minimum number of shooting nodes required for numerical convergence and to provide a method increasing convergence radius of the indirect method. The results of this study can provide an approach to improve numerical stability and convergence of the indirect method when we solve the optimal control problems of an inherently unstable helicopter system.

• Journal of Technologic Dentistry
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• v.30 no.2
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• pp.23-29
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• 2008

The purpose of this study is to evaluate possibility of using indirect composite resin instead of porcelain through the measurement of shear bond strength between zirconia core and indirect composite resin under treatment of $Rocatec^{TM}$ system for improving the adhesion of indirect composite resin. 20 cylindrical zirconia core specimens were divided into 2 groups, according to zirconia surface treatment and attached materials: 1) treated with sandblast and attached with indirect composite resin, 2) treated with sandblast + $Rocatec^{TM}$ system and attached with indirect composite resin. The shear bond strength of each experimental group was measured by MTS and the changes of zirconia core surface according to surface treatments were obtained by SEM observation and measurements of surface roughness. The mean shear bond strength values are $0.55\;{\pm}\;0.11MPa$(Group SC) and $1.16\;{\pm}\;0.46MPa$(Group SRC). The mean Ra values for the surface treatments were follows: $0.39\;{\pm}\;0.13$($100{\beta}_{{\mu}m}$ sandblast) and $0.50\;{\pm}\;0.03$($100{\beta}_{{\mu}m}$ sandblast + $Rocatec^{TM}$ system). In the analysis of EDS, Si element was detected in the Group SC. The shear bond strength between zirconia core and indirect composite resin was improved significantly by using $Rocatec^{TM}$ system.

• Korean Journal of Child Studies
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• v.35 no.3
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• pp.157-176
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• 2014

A total of 378 $4^{th}$ and $5^{th}$ grade elementary school students (194 boys and 184 girls) participated in a study investigating the direct and indirect effects (through self-esteem and/or achievement motivation) of children's perceptions of parental expectations on school happiness. First, parental expectations did not have a direct effect on children's levels of school happiness. Second, parental expectations did not have an indirect effect on children's school happiness through self-esteem. Children who perceived higher levels of parental expectations showed higher levels of self-esteem, but the path from children's self-esteem to school happiness was not significant. Third, parental expectations had an indirect effect on children's levels of school happiness through achievement motivation. Children who perceived higher levels of parental expectations showed higher levels of achievement motivation, and children with higher levels of achievement motivation reported higher levels of school happiness. Finally, parental expectations indirectly influenced children's school happiness through self-esteem and achievement motivation. These findings suggest that both environmental and individual factors need to be considered together to more comprehensively explain children's levels of school happiness.

• Journal of Korean Academy of Nursing
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• v.34 no.3
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• pp.541-551
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• 2004

Purpose: This study was to identify the effects of the predictive factors of Internet addiction and to develop a predictive model that explains Internet addiction among adolescents in Korea. Method: Data was collected from 664 adolescents in Puasan and Ulsan. Data analysis was done using the SPSS 10.0 Win Program for descriptive and correlational statistics and the LISREL 8.53 Win Program for Covariance structural analysis. Result: The fit of the hypothetical model to the data was moderate, it was modified by deleting four paths. Compared to the hypothetical model, the revised one had a better fit to the data($\chi^2$/df=6.50, GFI=.99, AGFI=.90, RMR=.02, NNFI=.88, NFI=.98, CN=279). Gender, friend support, and loneliness had significant direct effects on Internet addiction. The direct and indirect effect of self-esteem on Internet addiction was significant. The indirect effect of family support on Internet addiction was significant but its direct effect was insignificant. The direct and indirect effects of stress and impulsiveness on Internet addiction were significant but their total effects were insignificant. Conclusion: Finally, to decrease loneliness, and to increase family support and self-esteem, an effective intervention program and education should be developed to prevent Internet addiction of adolescents.

• Korean Journal of Childcare and Education
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• v.14 no.1
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• pp.1-20
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• 2018

Objective: The purpose of this study was to examine the direct and indirect effects (through working mothers' overprotective parenting behavior) of working mothers' separation anxiety and job satisfaction on preschoolers' separation anxiety. Methods: A total of 251 working mothers with preschool-aged children participated in this study. Mothers completed a questionnaire concerning their separation anxiety, job satisfaction, overprotective parenting behavior, and preschoolers' separation anxiety. Data were analyzed using t-test, one-way ANOVAs, partial correlations and path analysis. Results: In terms of direct effects, working mothers' separation anxiety had a direct effect on preschoolers' separation anxiety. However, job satisfaction did not have a direct effect on preschoolers' separation anxiety. With respect to indirect effects, working mothers' separation anxiety indirectly influenced preschoolers' separation anxiety through their overprotective parenting behavior. However, mothers' job satisfaction did not have an indirect effect on preschoolers' separation anxiety. Conclusion/Implications: Findings from this study emphasize the importance of reducing mothers' separation anxiety in order to prevent preschoolers' separation anxiety.

• The Korean Journal of Food And Nutrition
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• v.23 no.1
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• pp.15-22
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• 2010

This study was conducted to evaluate the antioxidative effect and antimutagenic capacity of ethanol extracts of Flammulina velutipes by employing biological and biochemical assays. The $IC_{50}$ of MDA with BSA conjugation reaction, lipid peroxidation and scavenging effect on DPPH radical in ethanol extracts of Flammulina velutipes was found to be 28.39 mg/assay, 9.33 mg/assay and 144.61 mg/assay respectively. Therefore, the most effective antioxidative capacity of ethanol extracts of Flammulina velutipes was $Fe^+$-induced linoleate peroxidation, among the method used this study. The indirect and direct antimutagenic effects of the ethanol extracts of Flammulina velutipes were examined by the Ames test using Salmonella typimurium TA98 and TA100. The inhibition rates on indirect mutagenicity mediated by 2-anthramine and on direct mutagenicity mediated by sodium azide in Salmonella typimurium TA100 and mediated by 2-nitrofluorene in Salmonella typimurium TA98 were 0%, respectively. These findings indicate that ethanol extracts of Flammulina velutipes have no effects on indirect and direct mutagenicity. Based on these results, it believed that the ethanol extracts of Flammulina velutipes has antioxidative capacities, and is a the candidate for the prevention and dietetic treatment of chronic diseases and the development of antioxidative functional food.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.6
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• pp.935-942
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• 2007

The purpose of this study was to measure the causal relationships among attitude toward eating seafood, perceived behavioral control (PBC), health involvement, behavioral intention and consumption. A total of 235 questionnaires were completed. A structural equation model was used to measure the causal effects of the constructs. The results of the study demonstrated that the structural analysis results for the data also indicated an excellent model fit. Health involvement had considerable effects on attitude and intention, which were statistically significant. The effects of attitude and PBC on intention were also statistically significant. Futhermore, the effects of attitude, PBC, and intention on consumption were statistically significant. As expected, intention had a significant effect on consumption. Moreover, health involvement had significant indirect effects on intention through attitude and PBC. Attitude had a significant indirect effect on consumption through intention. PBC also had a significant indirect effect on consumption through intention. By developing and testing conceptual models that integrated the relationship among variables such as health involvement and attitude, along with seafood consumption behavior, this study approaches a deeper understanding of how perceptions, on the importance of a healthy diet and other factors, influence consumption behavior.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.3 no.2
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• pp.183-199
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• 1996

The Purpose of this study is to develop and test a nursing model which can be applied to prediction of the quality of life for the patient receiving hemodialysis. A hypothetical model was constructed on Johns & Meleis's empowerment model framework which has 3 contsructs(stress, resource, empowerment). 6 Factors(perceived stress, self-esteem as personal resource, perceived social support as social resource, perceived fertigue, perceived health status & self efficacy as empowerment) were selected to pre dict the quality of life of receiving hemodialysis patients. 4 Factors(self-esteem, perceived social support, perceived health status & self efficacy) had direct effects on the quality of life significantly. Self-esteem had indirect effect on the quality of life via perceived heath status significantly. Perceived social support had indirect effect on the quality of life via self-effcacy significantly. Perceived stress had no direct and indirect effect on the quality of life significantly. Revised model from hypothetical model showed better fit to the data by eliminating unsignificant path. From results of this study we suggest that to improve quality of life of hemodialysis patient nurses provide nursing interventions which improve self-esteem, perceived social support, self-efficacy & perceived health status.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.28 no.1
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• pp.53-60
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• 2022

Background: The aim of the study is to examine whether mediating or moderating effects of stress between teachers' work environment and work-related musculoskeletal disorders. Methods: Two hundred nine participants took part in the study and completed the surveys including work environment, stress and work-related musculoskeletal disorders questionnaires. Hayes's PROCESS macro was used to test the research models for mediating and moderating effects of stress between work environment with teachers and work-related musculoskeletal disorders. Indirect effect was tested using bootstrapped confidence intervals. Results: The result confirmed that Stress served as a indirect mediator between work environment and work-related musculoskeletal disorders, whereas there was no significant the moderating effect. Conclusion: Stress mediates the relationship between work environment and work-related musculoskeletal disorders. Therefore, it is crucial that teachers' work environment that increases stress should be enhanced to reduce work-related musculoskeletal disorders.