• 한국해양공학회지
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• 제18권1호
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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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• 제10권4호
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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.

• 한국안전학회지
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• 제8권1호
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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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• 제26권1호
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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.

• 산업경영시스템학회지
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• 제40권3호
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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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• 한국전산유체공학회 2008년도 학술대회
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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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• 한국전산유체공학회 2008년 추계학술대회논문집
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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.

• 셀메드
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• 제14권2호
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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.

• 초등상담연구
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• 제9권2호
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• pp.175-193
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• 2010

본 연구는 어린이 요가프로그램이 초등학생의 학교 스트레스에 미치는 효과를 검증하는 데 있다. 이를 위해 B시 M초등학교 3학년의 6개 반 학생 231명 중 10명을 연구의 대상으로 무선 선발하여 8주간, 45분씩 총 16회기의 어린이 요가프로그램을 방과 후에 실시하였다. 프로그램의 처치효과를 측정하기 위하여 문화 기술적 면접법(ethnographic interview)을 사용하였다. 어린이 요가프로그램의 초기에 참여한 아동들을 대상으로 초기면담을 실시하고 면담내용을 영역분석, 분류분석의 과정을 거쳐 초등학생이 지각하는 학교 스트레스의 영역분류표로 작성하였다. 그리고 요가 참여 후기에 이를 토대로 후기면담을 실시하여 학교 스트레스의 변화 정도를 대조하여 성분분석을 함으로써, 어린이 요가프로그램의 효과를 검증하고자 하였다. 자료분석의 과정에서 누락되거나 보완할 내용이 발견되면 추가하는 순환과정을 거쳤다. 문화기술적 면접법을 사용하여 학교 스트레스의 요인을 찾아내고 변화를 확인한 본 연구의 결과, 어린이 요가프로그램은 초등학생의 학교 스트레스를 감소시키는데 상당히 긍정적인 효과가 나타났다. 이러한 연구의 결과를 하위 영역별로 살펴보면 다음과 같다. 첫째, 초기면담을 통해 초등학생의 학교 스트레스의 영역은 크게 학업 스트레스, 친구관계 스트레스, 교사관계 스트레스, 학교환경 스트레스의 4가지 영역으로 분석되었다. 둘째, 학업 스트레스는 과제, 수업, 시험성적이라는 3가지 하위영역으로 분류되었으며, 이 하위영역은 스트레스 감소의 효과가 작았다. 셋째, 친구관계 스트레스는 괴롭힘, 소외, 역할수행이라는 3가지 하위영역으로 나타났으며 괴롭힘과 소외영역의 스트레스는 감소되었지만 역할수행 스트레스는 상대적으로 효과가 적었다. 넷째, 교사관계 스트레스는 편애, 벌칙, 교수진행이라는 3가지 하위영역으로 분류되었으며 편애와 벌칙에 따른 스트레스는 감소 되었지만 교수진행 스트레스는 상대적으로 효과가 적었다. 다섯째, 학교환경 스트레스는 학교급식, 학교시설이라는 2가지 하위영역으로 구성되어 있었으며, 학교환경 스트레스는 감소되었지만 학교시설 스트레스는 상대적으로 효과가 적게 나타났다. 문화기술적 면접법을 사용한 본 연구의 결과를 통하여 아동의 다양한 스트레스 요인이 밝혀졌으며, 요가 프로그램의 처치 방법에 대한 시사점이 검토되었다.

• 한국작물학회지
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• 제69권1호
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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.