• Structural Engineering and Mechanics
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• v.59 no.6
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• pp.951-972
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• 2016

The purpose of this study is to illustrate the propagation of the shear waves (SH-waves) in a prestressed hetrogeneous orthotropic media overlying a pre-stressed anisotropic porous half-space with self weight. It is considered that the compressive initial stress, mass density and moduli of rigidity of the upper layer are space dependent. The proposed model is solved to obtain the different dispersion relations for the SH-wave in the elastic-porous medium of different properties. The effects of compressive and tensile stresses along with the heterogeneity, porosity, Biot's gravity parameter on the dispersion of SH-wave are shown numerically. The wave analysis further indicates that the technical parameters of upper and lower half-space affect the wave velocity significantly. The results may be useful to understand the nature of seismic wave propagation in geophysical applications and in the field of earthquake and material science engineering.

• Journal of the Korean Electrochemical Society
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• v.8 no.1
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• pp.47-54
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• 2005

This article covers the fundamentals of stress-induced diffusion, focusing on the theoretical model for hydrogen transport through self-stressed electrode. First, the relationship between hydrogen diffusion and macroscopic deformation of the electrode specimen was briefly introduced, and then it was classified into the diffusion-elastic and elasto-diffusive phenomena. Next, the transport equation for the flux of hydrogen caused simultaneously by both the concentration gradient and the stress gradient was theoretically derived. Finally, stress-induced diffusion was discussed on the basis of the numerical solutions to the derived transport equation under the permeable and impermeable boundary conditions.

• Steel and Composite Structures
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• v.7 no.1
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• pp.35-52
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• 2007

The cold formed light-gauge profiled steel sheeting can offer considerable shear resistance acting in the steel building frame. This paper conducted the full-scale test on the shear behavior of stressed skin diaphragm using profiled sheeting connected by the self-tapping screws. A three-dimensional finite element model that simulates the stressed skin diaphragm was developed. The sheet was modeled using thin element model while the supporting members were simulated using beam elements. Fasteners were represented in the numerical model as equivalent springs. A joint test program was conducted to characterize the properties of these springs and results were reported in this study. Finite element model of the full-scale test was analyzed by use of the ANSYS package, considering nonlinearity caused by the large deflection and slip of fasteners. The experimental data was compared with the results acquired by the EUR formulas and finite element analysis.

• English Language & Literature Teaching
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• v.13 no.2
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• pp.91-108
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• 2007

This study investigates learners' perception on their engagement in rating activities in the EFL essay-writing context. The current study aims to address the answers to the following research questions: 1) What attitude do students show about their participation in the rating tasks? and 2) which of three aspects (e.g. the degree of rating experience, the exposure to English composition instruction and learning, and proficiency level) significantly influences learners' rating activities? 104 EFL learners participated in the rater training session. After participants finished rater training session, they rated three sample essays and peer essays using the given scoring guide. Based on the analysis of survey responses that students made, students showed positive attitude toward their engagement in rating tasks. For research question 2, only L2 writing proficiency seriously affected students' perception on the rating tasks. Advanced level of subjects did not feel stressed by a grade of peers as low level of subjects did. They were also critical about the benefits of self- and peer-assessment, suggesting that a peer's feedback on their own essay was not so useful and that a self-rating does not fully help learners identify their writing proficiency.

• Korean Journal of Health Education and Promotion
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• v.33 no.1
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• pp.33-40
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• 2016

Objectives: The study aimed to determine the prevalence of and the relationship between stress and musculoskeletal symptoms among undergraduate students. Methods: The convenience sampling method was used for this cross-sectional survey that was conducted from June 16, 2014 to June 21, 2014. A total of 223 subjects (88 men, 135 women) participated in the study and completed a comprehensive self-administered questionnaire requesting information on demographics, medical history, lifestyle, and musculoskeletal symptoms. The Depression Anxiety Stress Scale (DASS) was also administered to the subjects. A total of 223 subjects from 12 universities completed the questionnaires; the data obtained was used for the final statistical analysis. Results: Women had a higher prevalence of stress and musculoskeletal symptoms. Adjusting for sex and age, subjects who were stressed had a 2.85-fold higher risk of musculoskeletal symptoms than subjects who were not stressed. Stratified analyses by sex also showed that women had a higher risk of musculoskeletal symptoms (Modified OR 2.98, 95% CI 1.38-6.45). Conclusions: We found a positive association between stress and musculoskeletal symptoms in undergraduate students; sex differences were present. Further dose-response relationship between stress and musculoskeletal symptoms will be identified by a longitudinal study with a larger sample size.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.4
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• pp.313-320
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• 2014

A tensegrity structure consists of a set of continuous cables in tension and a set of discontinuous struts in compression. The tensegrity structure can be classified into self-stressed and pre-stressed pin-jointed structure. A key step in the design of tensegrity structures is the determination of their equilibrium configuration, known as form-finding. In this paper, three effective methods are presented for form-finding of tensegrity structures. After performing form-finding process, a set of force density and corresponding topology results can be obtained. Then the force density method combined with a genetic algorithm is adopted to uniquely define a single integral feasible set of force densities. Numerical examples are presented that demonstrate the excellent performance of the algorithms.

• The Korean Journal of Community Living Science
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• v.17 no.3
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• pp.109-121
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• 2006

This study examines the relationship between mother's stress and cortisol level during late pregnancy and how it changes into postpartum periods. Thirty one families were recruited from Daejeon and Incheon in South Korea. The major findings were as follows: (1) The level of mothers' cortisol followed the typical diurnal pattern of decline throughout the day. Further longitudinal analysis revealed that the level of Korean mothers' cortisol steadily lowered from the 8th prenatal month to the 6th postnatal month. (2) During pregnancy, mothers reported to experience changes in physical activities, daily routines, eating habits, types or amount of social activities and sleeping habits. Among these they were stressed the most by changes in physical activities and social activities. (3) The results of postpartum depression tests conducted at two months after giving birth showed mothers at this time were mostly stressed from difficulty sleeping and unnecessary self criticism. (4) The level of psycho social stress in mothers at six months after giving birth was mainly on social roles and the questions about self reliance marked the highest points. (5) Overall, there was a tendency for the level of maternal stress to decrease definitely from before and after the delivery and even though the level of stress was steadily decreasing up to 6th postpartum month it was not as sharp as those of before and after the birth of the babies. The level of cortisol analysis also showed the same obvious tendency.

• Safety and Health at Work
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• v.11 no.3
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• pp.347-352
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• 2020

Background: Low self-esteem can be an issue among health-care workers due to the hierarchical medical system. Health-care workers are also in a high pressure environment that can lead to stress and burnout. This study was conducted to estimate the proportion of health-care workers with low self-esteem, high stress, and burnout and the factors associated with these in a private hospital in Bangalore city. Methods: This cross-sectional study included a random sample of health-care workers of various cadres - doctors, nurses, nursing aides, technicians, and workers in ancillary departments such as laundry, dietary, central sterile supply department, and pharmacy, with probability proportional to size. Rosenberg Scale for Self-esteem, Cohen's Perceived Stress Scale, and Shirom-Melamed Burnout Measure were used as study tools. Results: Among the 306 health-care workers, there were high levels of low self-esteem (48.4%), stress (38.6%), and burnout (48.7%), with the lowest levels being among doctors. Those aged younger than 30 years had significantly lower self-esteem and greater stress. Conclusions: Health-care workers with low self-esteem were nearly thrice more likely to suffer high stress, Odds Ratio (OR) = 2.84 (1.36-5.92), and those who were stressed had more than three times higher chance of experiencing burnout, OR = 3.6 (2.02-6.55). Path analysis showed that low self-esteem among health-care workers had a direct effect on burnout, as well as an indirect effect through stress (mediator variable). This study indicates the need for screening and counseling for low self-esteem, stress, and burnout as part of a periodic medical examination of all cadres of health workers.

• The Korean Journal of Health Service Management
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• v.10 no.3
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• pp.173-184
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• 2016

Objectives : This research analyzed the general characteristics of care workers and verified the correlation among self-perceived health, job stress and customer orientation. Methods : We conducted a survey from May 1st, to May 31st, 2015 of 260 care workers who are affiliated with elderly care facilities or home care facilities in Busan, Korea. Results : The more the workers were stressed about their organizational culture, the more they recognized psychological difficulties. However, there was no correlation between organizational culture and their tendency to be oriented toward customers. It was verified that the recognized psychological health has a positive regulation effect between customer orientation and job stress such as job skill requirement(p<0.01), job autonomy(p<0.01), and organizational culture(p<0.01). Conclusions : Because both suppliers and recipients of care services are aging, it is necessary for elderly care facilities to make a greater effort to minimize the physical and psychological losses of recipients.

• Journal of the Korean Home Economics Association
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• v.43 no.9 s.211
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• pp.71-84
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• 2005

The purpose of this study was firstly to identify how the characteristics of children(grades, birth order, self-consciousness), parents(age, educational level, employment status of mother, mother's parenting behavior), and context (private tutoring status, tying area) relate to children's stress and secondly to examine the relative effects of these variables on children's stress. The subjects of this study were 940(453 boys, 440 girls) children from grades 4 to 6 who were selected from three elementary schools in Seoul and Buchun. Data were analyzed with t-test, correlation, and multiple regression analysis. The results were as follows: (1) Girls get stressed easier than boys in terms of being treated distantly by their friends. (2) The study showed a negative relationship between children's stress and their self-consciousness such as general self-consciousness, teaming self-consciousness and total self-consciousness. (3) While the results showed a negative relationship between children's stress and mothers' acceptable behavior, the study revealed a positive relationship between children's stress and the mother's over protective behavior which in turn raised the children's stress level. (4) In 'total stress', it was recognized that boys were affected mostly tv grades in the children's variables category, while girls were affected by their general self-consciouness. In addition, both girls and boys were affected mostly by acceptable-refusal parental behavior in the parental variables category, and further affected by the living area in the category of conditional variables.