• Journal of the Korean Geosynthetics Society
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• v.15 no.3
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• pp.1-12
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• 2016

In this study, the impact of sand and weathered granite soil is analyzed by changing the internal temperature from $20^{\circ}C{\sim}70^{\circ}C$C by installing a heating coil inside the triaxial cell. To check the effect on weathered granite soil due to increase of temperature and number of heating-coiling cycles are analyzed by measuring the temperature by using thermometer installed inside the triaxial cell and due to that deviator stress also occurred during the consolidated undrained test. To analyze the effect of weathered granite soil with change of temperature during undrained testing. The deviator stress and pore pressure is measured. As a result, pore pressure increases and the deviator stress decreases with rise of temperature.

• Journal of the Korea Concrete Institute
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• v.19 no.6
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• pp.727-734
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• 2007

The influence of the differences in the physical and mechanical properties between fiber-reinforced polymer (FRP) and conventional steel, concentrated reinforcement in the immediate column region, as well as using steel fiber-reinforced concrete (SFRC) in the slab near the column faces, on the punching behavior of two-way slabs were investigated. The punching shear capacity, stiffness, ductility, strain distribution, and crack control were investigated. Concentrating of the slab reinforcement and the use of SFRC in the slab enhanced the punching behavior of the slabs reinforced with glass fiber-reinforced polymer (GFRP) bars. In addition the test results of the slabs with concentrated reinforcement were compared with various code equations and the predictions proposed in the literature specifically for FRP-reinforced slabs. An appropriate method for determining the reinforcement ratio of slabs with a banded distribution was also investigated to allow predictions to properly reflect the benefit of the slab reinforcement concentration.

• Journal of the Korean GEO-environmental Society
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• v.14 no.11
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• pp.33-46
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• 2013

Recently, the projects which are to increase the capacity of the flood control are being actively performed because of the abnormal climate changes throughout the country. In this study, the regression analysis was performed using both Kelvin model and the real settlement measured at the crest of the existing concrete face rockfill dam(CFRD) to estimate the long-term deformation behavior characteristics such as creep which occurs without additional load. In addition, the effects on changes in physical properties (E, G, K) of the dam construction materials by deformation characteristics of the dam were evaluated, and the reasonable stability analysis method of the dam was proposed to obtain the long-term stability considering the changes in physical properties induced by the long-term deformation behavior in case of heightening the existing dams.

• Structural Engineering and Mechanics
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• v.85 no.2
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• pp.179-195
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• 2023

The performance of reinforced concrete (RC) beam specimens strengthened using a newly proposed Side Near Surface Mounted (S-NSM) technology was investigated experimentally in this work. In addition, analytical and nonlinear finite element (FE) modeling was exploited to forecast the performance of RC members reinforced with S-NSM utilizing steel bars. Five (one control and four strengthened) RC beams were evaluated for flexural performance under static loading conditions employing four-point bending loads. Experimental variables comprise different S-NSM reinforcement ratios. The constitutive models were applied for simulating the non-linear material characteristics of used concrete, major, and strengthening reinforcements. The failure load and mode, yield and ultimate strengths, deflection, strain, cracking behavior as well as ductility of the beams were evaluated and discussed. To cope with the flexural behavior of the tested beams, a 3D non-linear FE model was simulated. In parametric investigations, the influence of S-NSM reinforcement, the efficacy of the S-NSM procedure, and the structural response ductility are examined. The experimental, numerical, and analytical outcomes show good agreement. The results revealed a significant increase in yield and ultimate strengths as well as improved failure modes.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.8
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• pp.199-208
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• 2019

The escape theory is the theory of problem behavior such as suicide. The purpose of this study is to investigate the causes of gaming disorder, which has been attracting attention as a typical youth problem, through escape theory. Suicide theory is a process in which the problem triggered by the negative external environment flows into internal attribution and self-criticism, and this leads to a process leading to problematic behavior with disgust self-awareness. This process was applied to the environment, psychology, and behavior of adolescents. As a result, the lack of affection and consistency of the parents resulted in negative external environment, which affected the self-esteem of children by creating a negative external environment. And low self-esteem caused negative emotions, lowered self control, and confirmed to induce game addiction. The results of this analysis show that game addiction has a structure similar to obsessive behaviors such as binge eating and shopping addiction explained through the escape theory model and it is necessary to concentrate more on the environmental psychological factors for game addiction research.

• Smart Structures and Systems
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• v.19 no.1
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• pp.21-31
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• 2017

To control the stochastic vibration of a vibration-sensitive instrument supported on a beam, the beam is designed as a sandwich structure with magneto-rheological visco-elastomer (MRVE) core. The MRVE has dynamic properties such as stiffness and damping adjustable by applied magnetic fields. To achieve better vibration control effectiveness, the optimal bounded parametric control for the MRVE sandwich beam with supported mass under stochastic and deterministic support motion excitations is proposed, and the stochastic and shock vibration suppression capability of the optimally controlled beam with multi-mode coupling is studied. The dynamic behavior of MRVE core is described by the visco-elastic Kelvin-Voigt model with a controllable parameter dependent on applied magnetic fields, and the parameter is considered as an active bounded control. The partial differential equations for horizontal and vertical coupling motions of the sandwich beam are obtained and converted into the multi-mode coupling vibration equations with the bounded nonlinear parametric control according to the Galerkin method. The vibration equations and corresponding performance index construct the optimal bounded parametric control problem. Then the dynamical programming equation for the control problem is derived based on the dynamical programming principle. The optimal bounded parametric control law is obtained by solving the programming equation with the bounded control constraint. The controlled vibration responses of the MRVE sandwich beam under stochastic and shock excitations are obtained by substituting the optimal bounded control into the vibration equations and solving them. The further remarkable vibration suppression capability of the optimal bounded control compared with the passive control and the influence of the control parameters on the stochastic vibration suppression effectiveness are illustrated with numerical results. The proposed optimal bounded parametric control strategy is applicable to smart visco-elastic composite structures under deterministic and stochastic excitations for improving vibration control effectiveness.

• Journal of Korean Academy of Nursing
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• v.43 no.5
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• pp.613-625
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• 2013

Purpose: This study was conducted to determine the effects of a fall prevention program on falls, physical function, psychological function, and home environmental safety in frail elders living at home in rural communities. Methods: The design of this study was a nonequivalent control group pre posttest design. The study was conducted from July to November, 2012 with 30 participants in the experimental group and 30 in the control group. Participants were registered at the public health center of E County. The prevention program on falls consisted of laughter therapy, exercise, foot care and education. The program was provided once a week for 8 weeks and each session lasted 80 minutes. Results: The risk score for falls and depression in the experimental group decreased significantly compared with scores for the control group. Compliance with prevention behavior related to falls, knowledge score on falls, safety scores of home environment, physical balance, muscle strength of lower extremities, and self-efficacy for fall prevention significantly increased in the experimental group compared with the control group. Conclusion: These results suggest that the prevention program on falls is effective for the prevention of falls in frail elders living at home.

• Journal of Korean Academy of Nursing
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• v.33 no.8
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• pp.1101-1110
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• 2003

Purpose. The purpose of this study was to identify the stage of change of smoking cessation behavior and investigate factors associated with the stage of smoking cessation behavior according to the transtheoretical model. Methods. The participants, 297 smokers & quitters were selected by a stratified random sampling from 127 high school sophomore students in B city. Data were collected from April 6th to 16th, in 2002 using the structured self-report questionnaire. Results. The subjects were distributed in each stage of change of smoking cessation behavior: there were 46 subjects (15.5%) in precontemplation, 73 subjects (24.6%) in contemplation, 67 subjects(22.3%) in preparation, 56 subjects (18.5%) in action, 55 subjects (18.5%) in maintenance. Compared to the precontemplation and contemplation, people in preparation tended to smoke daily more and smoked for a shorter time, and as precontemplation progressed to the maintenance, past 1 year smoking cessation frequency increased and friends smoking decreased. Smoking onset age was the earliest in preparation, and the latest in maintenance. Helping relationships and self relationships are used a lot in precontemplation and also in contemplation. In preparation, self liberation and helping relationships are used a lot, in action, self liberation and helping relationships, and in maintenance, self liberation and environmental reevaluation. At each stage, the score of negative affect situation was the highest, but the one of negative affect situation, positive social situation, habitual strength, weight control decreased as precontemplation progressed to the maintenance. While the score of social pros and coping pros decreased with increasing stage, the one of cons tended to increase. Through stepwise discriminant analysis, it was found that social pros, smoking onset age, delf-libration were the most influencing powers among factors associated with the stages of smoking cessation behavior. Conclusions. This study suggested that, in developing an effective smoking cessation intervention for adolescents, all the stage of a client's cessation had to be assessed prior to applying intervention programs. In addition, the results of this study will become a pillar of smoking cessation program planning and application.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.6
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• pp.52-61
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• 2001

The main purpose of this study is to analyze the differences of accompanying with environment interpreter in the ecological parks, and providing fundamental knowlege on the effective management method of the ecological parks by reviewing the effects of accompanying environmental parks in the ecological parks. We had done a field experimental design in the Gil-Dong ecological park, and evaluated the differences in the education effects, used types and satisfaction by the educational types - one is control groups, i.e., accompanying without environment interpreter and the other is treatment groups, ie., accompanying with environment interpreter through questionnaire survey and observation survey. The results of study are as follows; 1) In the respect of the effect of knowledge conveyance of the environmental interpreter, there appears higher educational effects of environment and ecology to the visitors of Gil-dong ecological park with an environment interpreter. 2) Accompanying with environment interpreter made the visitors reduce the depreciative behavior but no difference at environmental attitude and satisfaction. This results provide us the effectiveness of the environment interpreters. And more theoretical study is required in the future research.

• Nuclear Engineering and Technology
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• v.46 no.3
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• pp.431-438
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• 2014

The effect of various pH agents on the corrosion behavior of carbon steel was investigated under a simulated secondary water chemistry condition of a pressurized water reactor (PWR) in a laboratory, and the steel's corrosion performance was compared with the field data obtained from Uljin NPP unit 2 reactor. All tests were carried out at temperatures of $50^{\circ}C-250^{\circ}C$and pH of 8.5 - 10. The pH at a given temperature was controlled by adding different agents. Laboratory data indicate that the corrosion rate of carbon steel decreased as the pH increased under the test conditions and the highest corrosion rate was measured at $150^{\circ}C$. This high corrosion rate may be related to high dissolution and instability of Fe oxide ($Fe_3O_4$) at $150^{\circ}C$. It was also found that an addition of ethanolamine (ETA) to ammonia was more effectivefor anticorrosion than ammonia alone, and that mixed treatment reduced 50% of iron or more at pHs of 9.5 or higher, especially in the steam generator (SG) and the moisture separator & re-heater (MSR).