• Journal of Ocean Engineering and Technology
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• v.18 no.1
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• pp.22-27
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• 2004

An orthotropic steel deck system is widely adapted form for a long-span bridge. It has many advantages, such as the big reduction of dead weight, the simplicity for erection, and the reduction of the construction period. However, an orthotropic steel deck system requires a lot of welding work, which may result in defects and deformation of connection. Therefore, the research for the general behavior and fatigue strength of the several details in orthotropic steel deck bridge is necessary. The fatigue failure with distortion results from secondary stress by out-of-plane deformation; these kinds of cracks are very difficult to measure, and can not be precisely calculated through finite element analysis. This stress concentration phenomenon generates the fatigue failure around the lower scallop of the transverse rib. This paper presents improved details of the intersection between the longitudinal rib and the transverse rib of an orthotropic steel deck bridge by the third dimensional hit size test, and the finite element method, which can minimize local stress through parametric study.

• Steel and Composite Structures
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• v.10 no.4
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• pp.317-329
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• 2010

According to the results of 9 circular concrete filled steel tube (CFT) push-out tests, a new theoretical model for average bond stress versus free end slip curve is proposed. The relationship between verage bond stress and free end slip is obtained considering some varying influential parameters such as slenderness ratio and diameter-to-thickness ratio. Based on measured steel tube strain and relative slip at different longitudinal positions, the distribution of bond stress and relative slip along the length of steel tube is obtained. An equation for predicting the varying bond-slip relationship along longitudinal length and a position function reflecting the variation are proposed. The presented method can be used in the application of finite element method to analyze the behavior of CFT structures.

• Journal of the Korean Society of Safety
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• v.8 no.1
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• pp.71-79
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• 1993

The welding implementation used widely in the industrial field is gradually increasing due to weight reduction. unlimited material thickness. simplified structure design. and 1 manufacturing time and cost reduction. The most significant factor that influences the fatigue crack growth rate is the residual stress generated during the welding process. Many researchers have studied the effect of the residual stress on crack growth behavior. Through a fatigue test in a various-thickness welded specimen. redistributed residual stress is measured as the crack is developed. Then. by superposing the measured residual stress on the K value obtained by the finite element method.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.1
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• pp.85-92
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• 2000

Common dental procedures(dental extraction & minor operation) are potentially stress-inducing in many patients, especially medically compromised patients. The body's response to dental stress involves the cardiovascular system(an increase in cardiovascular workload), the respiratory organ and the endocrine system(change in metabolism). To minimize the stress to the medical risk patient, the stress reduction protocol was established. The obtained contents were as follows: (1) Recognize the patient's degree of medical risk (2) Complete medical consultation before dental therapy (3) Schedule the patient's appointment in the morning (4) Monitor and record preoperative and postoperative vital signs (5) Use psychosedation during therapy (6) Use adequate pain control during therapy (7) Short length of appointment : do not exceed the patient's limits of tolerance (8) Follow up with postoperative pain/anxiety control (9) Telephone the higher medical risk patient later on the same day that treatment was given Though the stress reduction protocol above was applied to the dental extraction in medically compromised patients with the advanced infected teeth, the final responsibility for the complications(syncope, bleeding & infection, etc.) in a patient rests with the dentist who ultimately treats him. For the prevention of postextraction complications & poor prognosis, the authors treated the advanced infected teeth with the pulp extirpation, opening drainage through the canal and complete occlusal reduction. The final extraction and wound closure were then done after $1{\sim}2$ weeks. The final prognosis was comfortable without common complications.

• 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.

• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.347-354
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• 2008

We introduce a series of studies on turbulent skin friction drag reduction in wall-turbulence. First, an identity equation relating the skin friction drag and the Reynolds shear stress (the FIK identity) is introduced. Based on the implication of the FIK identity, a new analytical suboptimal feedback control law requiring the streamwise wall-shear stress only is introduced and direct numerical simulation (DNS) results of turbulent pipe flow with that control is reported. We also introduce DNS of an anisotropic compliant surface and parameter optimization using an evolutionary optimization technique.

• 한국전산유체공학회:학술대회논문집
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• 2008.10a
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• pp.347-354
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• 2008

We introduce a series of studies on turbulent skin friction drag reduction in wall-turbulence. First, an identity equation relating the skin friction drag and the Reynolds shear stress (the FIK identity) is introduced. Based on the implication of the FIK identity, a new analytical suboptimal feedback control law requiring the streamwise wall-shear stress only is introduced and direct numerical simulation (DNS) results of turbulent pipe flow with that control is reported. We also introduce DNS of an anisotropic compliant surface and parameter optimization using an evolutionary optimization technique.

• CELLMED
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• v.14 no.2
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• pp.1.1-1.4
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• 2024

Food is a fundamental aspect of human life, encompassing the cultural essentials of clothing, shelter, and sustenance. Experiencing the culture of individuals who speak the language one is learning through food has proven to be an effective means of enhancing learners' motivation. It can be presumed that direct exposure to Korean cuisine, either through consumption or preparation, will exert a profoundly positive psychological impact on Korean learners, contributing to psychological healing, indirectly evidenced by stress reduction. Therefore, this study conducted a survey among Korean learners in Japan to investigate the potential for psychological healing through engagement with Korean food.

• The Korean Journal of Elementary Counseling
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• v.9 no.2
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• pp.175-193
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• 2010

The aim of this study is to examine effects of a yoga program for children on school stress of the elementary school children. To achieve this goal, total 10 students out of 231 in 6 classes among the third graders in M elementary school in B city were selected as subjects for this study. After regular school hours, they participated in a children's yoga program for 16 times for 45 minutes per session in the course of 8 weeks. An ethnographic interview was conducted to identify the effects of the program. During the initial stage of the children's yoga program, the participants were interviewed preliminarily. An analysis of areas and an analysis of classifications were made based on the initial interview results, and an area classification table was drawn on the school stress perceived by the elementary school children. After the yoga program ended, a follow up interview was made to apply an analysis of components by comparing changes in the school stress level due to a yoga effect. A research report was written through a cycle of addition and supplement in which the previous data analysis was complemented and corrected by new findings of the study. As a result of the ethnographic interview to analyze the school stress perceived by the elementary school children, and an examination of the changes in the school stress level, the children's yoga program proved to be significantly effective in reducing the school stress. However there were limitations to a certain degree in stress reduction. Details of such findings in each sub-category are as follow. First, as a result of the initial interview analysis, the school stress was classified broadly into 4 categories of study stress, friendship stress, teacher stress, and school environment stress. Second, the study stress as the first category of the school stress was classified into 3 sub-categories of homework, class, and exam stresses. In spite of minor differences among 3 sub-categories, the stress was reduced in general. Third, the friendship stress as the second category of the school stress was also classified into 3 sub-categories of bullying, alienation, and performing one's duty. There were minor differences among sub-categories, however stress reduction also appeared with the exception of the performing one's duty category which had relatively little effect from the yoga program. Fourth, regarding the teacher stress as the third school stress, a classification was made into 3 sub-categories of preference, penalty, and teaching method. Minor differences among the 3 sub-categories notwithstanding, stress reduction appeared with the exception of the teaching method stress which had relatively little effect from the yoga program. Fifth, the school environment stress as the fourth category of the school stress was classified into 2 sub-categories of school meals and facilities. Minor differences between the 2 categories notwithstanding, stress reduction appeared with the facilities stress having relatively little effect.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.69 no.1
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• pp.1-14
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• 2024

High soil salinity is the most severe threat to global rice production as it causes a significant decline in rice yield. Here, we investigated the effects of various plant extracts on rice plant stress associated with high salinity. Additionally, we examined various physiological and biochemical parameters such as growth, photosynthetic activity, chlorophyll content, and lipid peroxidation - in rice plants after treatment with selected plant extracts under salt stress conditions. Of the 11 extracts tested, four - soybean leaf, soybean stem, moringa (Moringa oleifera), and Undaria pinnatifida extracts - were found to effectively reduce salt stress. A reduction of only 3-23% in shoot fresh weight was observed in rice plants under salt stress that were treated with these extracts, compared to the 43% reduction observed in plants that were exposed to stress but not given plant extract treatments (control plants). The effectiveness varied with the concentration of the plant extracts. Water content was higher in rice plants treated with the extracts than in the control plants after 6 d of salt stress, but not after 4 d of salt stress. Although photosynthetic efficiency (Fv/Fm), electron transport rate (ETR), and the content of pigments (chlorophyll and carotenoid) varied based on the types and levels of stress and the extracts that the rice plants were treated with, generally, photosynthetic efficiency and pigment content were higher in the treated rice compared to control plants. Reactive oxygen species (ROS), such as superoxide radicals, hydrogen peroxide (H₂O₂), and malondialdehyde (MDA), increased as the duration of stress increased. ROS and MDA levels were lower in the treated rice than in the control plants. Proline and soluble sugar accumulation also increased with the duration of the stress period. However, proline and soluble sugar accumulation were lower in the treated rice than in the control plants. Generally, the values of all the parameters investigated in this study were similar, regardless of the plant extract used to treat the rice plants. Thus, the extracts found to be effective can be used to alleviate the adverse effects of stress on rice crops associated with high-salinity soils.