• The Journal of Korean Academic Society of Nursing Education
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• v.18 no.1
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• pp.149-158
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• 2012

Purpose: The purpose of this study was to identify the factors influencing mental health among late elementary age children. Methods: The research design was a secondary data analysis. Data were collected from 746 students in grades 5 or 6, and analyzed using descriptive statistics, t-test, ANOVA, Pearson's correlation coefficients and stepwise multiple regression with the SPSS/PC 18.0 program. Results: The average score of mental health was $3.42{\pm}0.55$. There were significant differences in mental health according to health status, economic status, scholastic performance, relationships with friends, relationships with the teachers, atmosphere of the home, number of siblings and the source of trouble. Stepwise multiple regression analysis showed influencing factors of stress, negative reaction under stress, self-esteem, teacher support, and friend support support and explained 41.4% of total variance in late elementary age children's mental health. Conclusion: These results may contribute to a better understanding of mental health in late elementary age children. The results of the present study indicate a need to develop nursing interventions to prevent and manage elementary school-age children's negative reaction under stress.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.3
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• pp.215-222
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• 2021

As the importance of human-computer interaction (Human Computer Interface) technology grows and research on HCI is progressing, it is inferred about the research emotion inference or the computer reaction according to the user's intention, not the computer reaction by the standard input of the user. Stress is an unavoidable result of modern human civilization, and it is a complex phenomenon, and depending on whether or not there is control, human activity ability can be seriously changed. In this paper, we propose an intelligent emotional recommendation system using music as a way to relieve stress after measuring heart rate variability (HRV) and acceleration photoplethymogram (APG) increased through stress as part of human-computer interaction. The differential evolution algorithm was used to extract reliable data by acquiring and recognizing the user's biometric information, that is, the stress index, and emotional inference was made through the semantic web based on the obtained stress index step by step. In addition, by searching and recommending a music list that matches the stress index and changes in emotion, an emotional recommendation system suitable for the user's biometric information was implemented as an application.

• Journal of Biosystems Engineering
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• v.15 no.3
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• pp.177-185
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• 1990

The break of rotary blade is occured from a stress concentration of the inside of blade by the outside impulsive load. In order to examine its inside stress and stress concentration of rotary blade, a epoxy plate which is suitable to applicate by photoelastic system is used to experiment. These results are summarized as follow. 1. Refer to the existence of bolt hole and a size of its of rotary blade, a stress concentration which cause the break of rotary blade is not exposed. 2. It is expected to be break to section of hold of rotary blade and the break of this is due to that there are concentrated by shearing force, bending moment and bending stress. 3. When the crack which caused from processing are set up to any location, the stress concentration taken to the creak point. 4. Without regard to the location of the reaction points of rotary blade, the bending stress which is greated than the bending moment is occured within about 6 em toward the center line of bolt hole and it was possible to break that section.

• Design & Manufacturing
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• v.8 no.2
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• pp.46-49
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• 2014

Silicone is recently used for LED chip lense due to its good thermal stability and optical transmittance. In order to predict residual stress which causes optical briefringence and mechanical warpage of silicone, finite element analysis was conducted for curing process during silicone molding. For analysis of curing process, a dynamic cure kinetics model was derived based on the differential scanning calorimetry(DSC) test and applied to the material properties for finite element analysis. Finite element simulation result showed that the slow cure reduced abrupt reaction heat and it was predicted decrease of the residual stress.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.194-200
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• 2000

Researches on the FRF-based substructuring method have been mainly focused on vibratory response analysis. Present study is concerned about the application of the method to the dynamic stress analysis of a compressor mounting bracket in a passenger car. This is performed by using reaction forces that can be obtained by the FRF-based substructuring method. The air-conditioner system, composed of a compressor, a bracket and a test jig, is analyzed by using the FRF-based substructuring method. The experimental and numerical FRFs are combined to calculate the system responses and reaction forces at the connection point. The dynamic reaction forces plugged into the bracket FE model to compute the compute the stresses of the bracket. Dynamic stresses by the present method are compared with those from FE model. The comparison shows possibility of practical usage of the method for the real problem.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.11
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• pp.85-91
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• 2009

A lip seal is widely used not only to prevent leakage of fluids from an actuator or a rotating shaft but also to exclude outside substances. Recently, TPU(Thermoplastic Polyurethane), which is one of the sealing materials, has been frequently used due to its excellent mechanical properties and wear resistance. The material constants for finite element analysis through the experiment on stress relaxation are presented. The reaction forces of a shaft as well as the contact pressures of a lip seal under condition before and after stress relaxation using finite element analysis were obtained, The results show that stress relaxation has not a little effect on the performance of a lip seal.

• Journal of the korean Society of Automotive Engineers
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• v.5 no.1
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• pp.32-44
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• 1983

In case of $K_{Imax}$ < $K_{Iscc}$, the corrosion fatigue of high strength steel in 0.1N $H_{2}$S $O_{4}$ solution and 3.5% salt water is as follows. 1. The fatigue life shortens in order of 3.5% salt water and 0.1N $H_{2}$S $o_{4}$ solution. 2. The fatigue crack growth rate in air is obtained as the following equation. (dc/dN)$_{atr}$=7.23*10$^{-6}$ (.DELTA. K)$^{2.23}$ 3. The corrosion fatigue crack growth rate in environment is divided into three regions, that is, First Region, Second Region and Third Region from the small cyclic stress intensity. 4. The formation rate of the active surface on metal is slower than the mechano-chemical reaction rate in First Region. The crack growth rate depends on time and the cyclic stress intensity and is expressed as the following equation. (dc/dN)$_{I}$=C(/DELTA. K)$^{\delta}$ 5. The formation rate of the active surface is faster than the mechano-chemical reaction rate in Second Region and the synergistic effect by stress and corrosion becomes slow. In case the fatigue load is large, we have the critical crack growth rate which is not related to the cyclic stress intensity. 6. The corrosion crack growth rate by the mechano-chemical reaction is the same in $H_{2}$S $O_{4}$ solution and salt water, so Hydrogen accelerates the crack growth. 7. The environment has no effect on the corrosion fatigue crack growth rate in Third Region. 8. In First Region and Second Region, dimple is observed on the fatigue fracture surface in 0.1N $H_{2}$S $O_{4}$ solution. 9. The striation is observed in any environment as in air in Third Region and its interval approximately coincide with the crack growth rate.ate.e.e.

• Journal of the Korean Ceramic Society
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• v.36 no.1
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• pp.21-29
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• 1999

The effects of density and pore size distribution of substrate in preparing SiC conversiton layer on graphite substrate were investigated. The chemical reaction for formation of SiC conversion layer was occurred at substrate surface or below surface through SiC gas infiltration. It was supposed that the pore size distribution required for the sufficient SiO gas infiltration and the continuous chemical reaction during conversion process was in the range of 1.0∼10.0$\mu\textrm{m}$. In the stress analysis of SiC layer with finite element method (FEM), the residual stress distribution due to thermal mismatch was shown. However, the compressive stress was measured in SiC layer by X-ray diffraction, it was presumed that the residual stress distribution of SiC layer was mainly influenced by the constraining effect of interlayer between SiC layer and graphite substrate, and the densification behaviro and the grain growth in SiC conversion layer.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.141-149
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• 2000

This study performs the elastic and viscoelastic analysis of composite continuous beams with flexible shear connectors. Due to creep and shrinkage of the concrete part, the stress redistribution between the concrete slab and steel beam, and the evolution of the redundant restraint reaction occur with time. Using the equation of equilibrium, internal and external compatibility condition, and constitutive relationships, mathematical formulations are formulated. The solution is obtained by means of numerical step-by-step techniques and the finite difference method. Numerical parametric studies are performed to evaluate the stress redistribution, and the evolution of the redundant restraint reaction. The parameters include the stiffness and spacing of shear connectors, the age of concrete at loading, and the relative humidity.

• Korean Journal of Materials Research
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• v.9 no.4
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• pp.419-427
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• 1999

TiNi shape memory alloy was shape memory heat-treated and investigated its mechanical properties with the variation of prestrain. Also 6061 Al matrix composites with TiNi shape memory alloy fiber as reinforcement have been fabricated by Permanent Mold Casting to investigate the microstructures and interface properties. Yield stress of TiNi wire was the most high in the case of before heat-treatment and then decreased as increasing heat-treatment time. In each heat-treatment condition, the yield stress of TiNi wire was not changed with increasing the amount of prestrain. The interface bonding of TiNi/6061Al composite was fine. There was a 2$\mu\textrm{m}$ thickness of diffusion reaction layer at the interface. We could find out that this diffusion reaction layer was made by the mutual diffusion. The diffusion rate from Al base to TiNi wire was faster than that of reverse diffusion and the amount of the diffusion was also a little more than that of reverse.