• The Korean Journal of Community Living Science
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• v.26 no.3
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• pp.565-573
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• 2015

This study examines the relationships between stress and eating habits of adolescents based on the assumption that adolescents require large amounts of nutrients and that eating habits affect their physical development, academic achievement, and emotional development. For this purpose, 213 adolescents in Gangwondo, Korea, were surveyed. Many studies have reported that stress causes changes in eating habits and affects health status. Based on the dietary action guide scores according to stress categories, eating instant foods less was significant (p<0.001), eating fast foods less was significant (p<0.05), and have soft drinks less was significant (p<0.001). The results suggest the importance of balanced nutrition based on the formation of right dietary habits for adolescents. Good nutrition can be determined through right knowledge of nutrition and dietary habits, and right dietary habits can improve health and physical development as well as mental and emotional stability. The analysis did not compare other regions, and therefore any generalization of the results should be made with caution. However, the results offer important insights into stress among adolescents for their effective counseling.

• Geomechanics and Engineering
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• v.22 no.5
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• pp.375-384
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• 2020

In this study, the application of conventional cubic law to a deep depth condition was experimentally evaluated. Moreover, a modified equation for estimating the rock permeability at a deep depth was suggested using precise hydraulic tests and an effect analysis according to the vertical stress, pore water pressure and fracture roughness. The experimental apparatus which enabled the generation of high pore water pressure (< 10 MPa) and vertical stress (< 20 MPa) was manufactured, and the surface roughness of a cylindrical rock sample was quantitatively analyzed by means of 3D (three-dimensional) laser scanning. Experimental data of the injected pore water pressure and outflow rate obtained through the hydraulic test were applied to the cubic law equation, which was used to estimate the permeability of rock fracture. The rock permeability was estimated under various pressure (vertical stress and pore water pressure) and geometry (roughness) conditions. Finally, an empirical formula was proposed by considering nonlinear flow behavior; the formula can be applied to evaluations of changes of rock permeability levels in deep underground facility such as nuclear waste disposal repository with high vertical stress and pore water pressure levels.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.291-296
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• 2000

In this paper a relatively simple and reliable wall models are investigated, which are suitable to be efficiently incorporated in a practical nonlinear seismic analysis of reinforced concrete shear wall structural systems. Four types of analogous frames have been selected for the elastic stress analysis. Three types of macro-elements model which include wide-column model, truss model and Kabeyasawa model, are chosen for the use in nonlinear analysis. A numerical analysis is carried out for six stories plane coupled wall structure. Analysis results indicate that macro-elements wall model is effective and suitable for simulating stress in elastic analysis. In inelastic analysis, the yielding strength have little effect on different wall model, and the effect on post-yielding stiffness in story shear-drift relationship depend on force-deformation properties of macro-elements.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.4
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• pp.723-736
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• 1992

Most degeneating diseases and back pains in the orthopaedic disease are originated from the unbalance of stress distribution in the low-lumbar spine. Therefore the stress analysis of lowerback is indispensible to the clinical diagnosis for the developing reason and the developing process of diseases. Therefore the same model materials as following are eveloped to analyze the stress distributions of lower-back by photoelastic experiment. The verterbral body and the process are molded from epoxy resin(the weight ratio of Araldite and hardner is 10 to 3), models are geometrically identical to them in vivo respectively and the ratio of their elastic modulus to that of model material is 1 to 10. It is assured that KE-1300 Silicon(E=0.8MPa), TSE-3562 Silicon(0.5MPa) and the composite silicon(3MPa) (the weight ratio of KE-1300 silicon and Jioreal : 10 to 4) are respectively effective as the model materials of ligament, musles and intervertevral disc which is essential to the movement of low-lumbar spine. All the elements associated with the movement of the low-lumbar spine are molded through the molding method developed in this research and assembled with the angles between the verterbra and the disc in the normal human lumbosacral spine. The stress distributions of the assembled model are analyzed by photoelastic experiment. It is certified by comparing the results of photoelastic experimebt with the clinical situations that the loading dveice and the loading conceptions used in this paper are effective.

• International Journal of Highway Engineering
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• v.16 no.6
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• pp.59-67
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• 2014

PURPOSES : The purpose of this study is to analyse the longitudinal steel strain and stress of continuously reinforced concrete pavement(CRCP) with longitudinal and transverse direction at early age using stress dependent strain analysis method. METHODS : To measure the longitudinal steel strain, 9-electrical resistance and self-temperature compensation gauges were installed to CRCP test section (thickness = 250mm, steel ratio = 0.7%) and continuously measured 10min. intervals during 30days. In order to properly analyze the steel stress first, temperature compensation process has been conducted. Secondly, measured steel strains were divided into stress dependent strain (elastic strain) and stress independent strain (thermal strain) and then stress dependent strain was applied to stress calculation of longitudinal steels. RESULTS : Steel strains were successfully measured during 30days. To verify the accuracy of temperature compensation process, measured coefficient of thermal expansion(COTE,$11.46{\times}10^{-6}m/m/^{\circ}C$) of longitudinal steel before paving was compared with that of unrestrained steel. Max. steel stress in the transverse direction shows about 266MPa at 23days after placement. CONCLUSIONS : Steel stresses in the longitudinal and transverse direction have been evaluated. In longitudinal direction, steel stress from the crack was rapidly reduced from 183MPa at crack to 18MPa from 600mm apart the crack. From this observation, stress effective length can be identified as within 600mm apart from the crack. In transverse direction, max. stress point was located near the center of pavement width and stress level(266MPa) is about 66% of yield stress of steel.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.3
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• pp.107-115
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• 2017

The purpose of this study is to find and compare the differences in stress level, stressor, and coping style of high school students according to their personality traits. And to identify the personality traits contributing to stress reduction. The results of the study can be used as basic data for reducing the stress of adolescents to improve their academic achievement and maintain mental and physical stability. The questionnaire survey was conducted for 10 days from June 7 to June 16, 2017 for S high school students in Chungbuk Province. The study employed four measuring instruments as Ego-gram, Ok-gram, stressor scale, and stress coping type scale. Individual personality traits were classified into ego-states and ok-states in TA (Transactional Analysis). Stressors are classified into 5 categories (school life, home life, human relationship, myself, environment) and stress coping styles are classified into 4 categories (problem-focused coping, social-support coping, feeling-focused coping, hope-thinking coping) used in the previous studies. The collected data were analyzed using T-test, ANOVA, and multiple regression analysis. As a result, the stress level of high school students showed significant differences according to sex, year, grade, sleeping time, personality traits, and coping styles. Personality traits that contributed to the stress increase were NP, AC, 'you positive', 'i negative' and personality trait that contributes to stress reduction is 'you negative.' Therefore, we can judge that individual personality traits have significant effects on stress level, stressor, and coping style and need to find the effective stress management method suitable for individual personality traits using counseling, repetition training, self-suggestion etc.

• Steel and Composite Structures
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• v.33 no.3
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• pp.463-472
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• 2019

Initial thermo-elastic and steady state creep deformation of a rotating functionally graded simple blade is studied using first-order shear deformation theory. A variable thickness model for cantilever beam has been considered. The blade geometry and loading are defined as functions of length so that one can define his own blade profile and loading using any arbitrary function. The blade is subjected to a transverse distributed load, an inertia body force due to rotation and a distributed temperature field due to a thermal gradient between the tip and the root. All mechanical and thermal properties except Poisson's ratio are assumed to be longitudinally variable based on the volume fraction of reinforcement. The creep behaviour is modelled by Norton's law. Considering creep strains in stress strain relation, Prandtl-Reuss relations, Norton' law and effective stress relation differential equation in term of effective creep strain is established. This differential equation is solved numerically. By effective creep strain, steady state stresses and deflections are obtained. It is concluded that reinforcement particle size and form of distribution of reinforcement has significant effect on the steady state creep behavior of the blade.

• Journal of Korean Academy of Nursing
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• v.49 no.4
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• pp.361-374
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• 2019

Purpose: This study was conducted to evaluate the effectiveness of autogenic training on stress responses through a systematic review and meta-analysis. Methods: A systematic search was conducted using eight core electronic databases (Embase, CENTRAL, Medline, CINAHL, PsycInfo, DBpia, KISS, and RISS). To estimate the effect size, a meta-analysis of the studies was performed using RevMan 5.3.5 program. Results: A total 21 studies out of 950 studies were included in the review, and 11 were included for meta-analysis. These studies showed that autogenic training decreased anxiety and depression, and increased the high frequency of heart rate variability. Calculations to understand the effect of autogenic training on anxiety, through a meta-analysis, observed a reduction effect of anxiety score by 1.37 points (n=85, SMD=-1.37: 95% CI -2.07 to -0.67), in the studies on short-term intervention targeting healthy adults. On the other hand, similar calculations to understand the effect of autogenic training on depression observed, a reduction effect on the depression score by 0.29 point (n=327, SMD=-0.29: 95% CI -0.50 to -0.07), in the studies on long term intervention targeting the patient group. Conclusion: Autogenic training is effective for adults' stress management, and nurses will be able to effectively perform autogenic training programs for workers' stress relief at the workplace.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1994.04a
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• pp.65-72
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• 1994

This study presents the application of multi-level substructuring for the effective nonlinear analysis of coupled wall structures. Also, the transition elements with 8 or 12 d. o. f, 5-node plane stress elements and concrete nonlinear model are considered as the basic finite elements of substructuring. In particular, the concept of localized nonlinearity is considered for the probable nonlinear zones of the structure, and the effective bottom-up and top-down process are presented through connectivity trees. The nonlinear analysis based on localized nonlinearity and multi-level substructuring, compared with the complete nonlinear analysis of the structure, gives the greater saving effects in computational efforts and cost.

• The Journal of Korean Society for School & Community Health Education
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• v.16 no.1
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• pp.27-38
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• 2015

Objectives: The purpose of this study is to develop programs that help students adjust to school and provide basic data for the students who have difficulty adjusting to school by analyzing the influence of elementary school students' stress and their relationship with parents on school adjustment. Methods: The study surveyed fourth graders in 3 elementary schools in G district. The researcher used convenience sampling to select the 3 elementary schools. The combined 158 students were selected for the analysis, and the survey was conducted for a month in September 2011. The stress monitoring tool used in the 5th year of Korean Youth Panel Survey was mobilized to measure levels of stress among the participants. To measure the parent-child relationship, the Korean Parent-Child Relationships Scale was used. For the measurement of school adjustment, a tool designed to identify the school adjustment of elementary school students was used. The SPSS 21 software and a two-sided test under the significance level of ${\alpha}=0.05$ were used to analyze data. The regression analysis was also used to identify the relative influence of the stress and parent-child relationship on children's adjustment to school. Results: The regression analysis has found the following: the higher peer stress (B=-0.175) and parental strictness (B=-0.159) grow, the lower the level of school adjustment gets; the higher the level of intimacy between parent and child gets, the higher the level of school adjustment grows; and intimacy between parent and child (${\beta}=0.400$) has the largest influence on the child's school adjustment. Conclusions: For elementary school students to be well adjusted to school, their stress and relationships with their parents should be managed. In particular, using the programs that can reduce stress from peers and increase parent-child intimacy will be effective in helping students adjust to school.