• 대한안전경영과학회지
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• 제12권4호
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• pp.31-39
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• 2010

The purpose of this study was to examine the effects of stress response on safety behavior and to explore moderating effect of safety climate between stress response and safety behavior. 224 workers were asked to respond to the questionnaires that measured various demographic variables, stress response, safety climates and safety behaviors. A hierarchical regression was conducted to identify variables that had significant relationships with safety behavior and to examine moderating effect of safety climate between stress response and safety behavior. Results indicated that the depression response significantly predicted safety behavior. It was found that the safety climate was also a significant predictor for safety behavior. In addition, safety climate had a moderating effect on the relation between depression and anger responses and safety behavior.

• Steel and Composite Structures
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• 제45권6호
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• pp.851-863
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• 2022

This research deals with the study of the Thomson heating effect in magneto-thermoelastic homogeneous isotropic rotating medium, influenced by linearly distributed load and as a result of modified couple stress theory. The charge density is taken as a function of the time of the induced electric current. The heat conduction equation with energy dissipation and with hyperbolic two-temperature (H2T) is used to formulate the model of the problem. Laplace and Fourier transforms are used to solve this mathematical model. Various components of displacement, temperature change, and axial stress as well as couple stress are obtained from the transformed domain. To get the solution in physical domain, numerical inversion techniques have been employed. The Thomson effect with GN (Green-Nagdhi) -III theory and Modified Couple Stress Theory (MCST) is shown graphically on the physical quantities.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.204-209
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• 2008

The interest in the mechanical behavior of materials at high strain rates has increased in recent years, and by now it is well known that mechanical properties can be strongly influenced by the speed of applied load. The split Hopkinson pressure bar (SHPB) has been widely used to determine mechanical properties of materials at high loading rates. However, to ensure test reliability, measurement error source must be accounted for and eliminated. During experiment, the specimens were located between the incident and the transmit bar. The presence of contact frictions between the test bars and specimen may cause errors. In this work, numerical experiments were carried out to investigate the effect of friction on test results. In SHPB test, the measured stress by the transmitted bar is assumed to be flow stress of the test specimen. Through the numerical experiments, however, it is shown that the measured stress by the transmit bar is axial stress components. When, the contact surface is frictionless, the flow stress and the axial stress of the specimen are about the same. When the contact surface is not frictionless, however, the flow stress and the axial stress are not the same anymore. Therefore, the measured stress by the transmitted bar is not flow stress. The effect of friction on the difference between flow stress and axial stress is investigated.

• Steel and Composite Structures
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• 제44권6호
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• pp.753-768
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• 2022

In this study, a graphical automatic system is developed in order to investigate the stress redistribution of structural members in a steel cable-stayed bridge. The generalized Maxwell model is selected for stress relaxation estimation, and it is carefully verified and applied to all the cable members of a steel cable-stayed bridge to investigate its stress relaxation. A set of stress relaxation parameters in all cables is determined using the fmincon optimization function. The stress redistribution of the steel cable-stayed bridge is then analyzed using ABAQUS. To shorten the investigation time, all the aforementioned phases are built up to be an automatic system. The automatic system is then employed to investigate the effect of cable cross-section areas and girder spans on stress redistribution. The findings from these studies show that the initial tension in the cables of a steel cable-stayed bridge should be kept to less than 55% of the cable's ultimate strength to reduce the effect of cable stress relaxation. The cable space in a steel cable-stayed bridge should be limited to 15,000 mm to minimize the effect of cable stress relaxation. In comparison to other structural members of a steel cable-stayed bridge, the girders experience a significant stress redistribution.

• 한국가스학회지
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• 제25권1호
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• pp.20-29
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• 2021

투과성이 낮은 셰일층에서의 다단계 수압파쇄 시, 파쇄단계 간의 서로 근접한 균열로 인해 지층 간 응력간섭이 발생하는 '응력그림자효과'가 나타날 수 있다. 이로 인해 균열의 전파 방향성이 변화하거나 비정형적인 형태의 균열이 발생하게 된다. 본 연구에서는 응력그림자효과의 영향에 따른 수압파쇄 균열형태와 생산성을 분석하고자 상용 수압파쇄 시뮬레이터 full-3D모델인 'GOHFER'를 사용하였다. 균질한 저류층 모델에서 응력그림자효과 고려 유무에 따른 분석을 수행하였다. 또한 지력학적 물성이 다른 두 셰일층에서 수압파쇄 모델링을 수행하여 영률과 포아송비에 따른 응력그림자효과를 분석하였다. 선행 파쇄단계의 균열로 인한 응력변화는 최대/최소 주응력을 역전시켜 T-방향보다는 생산성이 미비한 L-방향 균열이 주로 형성되었다. 또한 Marcellus 셰일의 경우 연성 특성을 갖는 Eagle Ford 셰일에 비해 높은 취성으로 인해 균열의 폭이 더 두껍게 형성되어 균열 체적이 더욱 크게 산출되었다. Marcellus 셰일지층의 영률이 Eagle Ford 셰일에 비해 크게 낮기 때문에 stage 2에서 응력그림자효과의 영향을 적게 받는 것을 확인할 수 있었다. 이처럼 응력그림자효과는 균열 간의 간격 뿐만 아니라 지력학적 물성에 따라서도 크게 달라진다. 그러므로 좀 더 정확한 균열 형태와 현실성 있는 생산성 예측하기 위해 응력그림자효과는 고려되어야 한다.

• 가정과삶의질연구
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• 제30권3호
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• pp.165-177
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• 2012

This study examined the effect of social support on infant mother's parenting behavior and mediating effects of parenting stress and depression between social support and maternal parenting behavior. Participants were 2078 mothers of infant (4-10 month) in Korea. Data were analyzed by Structural Equation Model. Major findings were as follows: First, social support showed direct effect on maternal parenting behavior. That was the more mother receive social support, mother show responsive and warmer parenting behavior on infant. Second, maternal parenting stress mediated the effect of social support on maternal parenting behavior. That was the more mother receive social support, the less mother experience parenting stress, which in turn contribute to responsive and warm parenting behavior. Third, Maternal depression didn't mediate the effect of social support on maternal parenting behavior. However, social support and maternal parenting stress showed direct effects on maternal depression. This research suggest the needs for development of diverse social support policies and program to help mothers reduce maternal parenting stress and depression.

• 대한간호학회지
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• 제50권6호
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• pp.813-821
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• 2020

Purpose: This study aimed to identify the actor and partner effects of daily stress and dyadic coping on marital satisfaction using the Actor-Partner Interdependence Mediational Model (APIeM). Methods: Participants were 314 couples who met the study's eligibility criteria. Data were collected from March to April 2016 through apartment and cooperative company communities in Seoul. Two APIeMs of positive and negative dyadic coping were analyzed using SPSS 20.0 and Mplus 7.4. All measures were self-administered. Results: Daily stress and positive and negative dyadic coping in both spouses had direct actor effects on their marital satisfaction. Daily stress in both spouses had an indirect actor effect on marital satisfaction through their positive and negative dyadic coping. The husband's daily stress had an indirect partner effect on the wife's marital satisfaction through his positive dyadic coping, while the wife's positive dyadic coping had a direct partner effect on the husband's marital satisfaction. The husband's daily stress had an indirect partner effect on the wife's marital satisfaction through his negative dyadic coping, while the wife's negative dyadic coping had a direct partner effect on the husband's marital satisfaction. Conclusion: Dyadic coping is an effective way to deal with couple's daily hassles as it increase their satisfaction in marriage.

• 대한안전경영과학회지
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• 제24권4호
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• pp.15-23
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• 2022

This study investigated the effects of job stress, job attitude, and social support on the relationship between client violence and social worker job response. The multi-mediating effect of job stress, job attitude, and social support between client violence and social worker job response was empirically analyzed. 257 social workers in social welfare facilities were analyzed using SPSS. The following conclusions were drawn. First, there was a significant correlation between client violence, job stress, job attitude, social support, and job response variables. Client violence was affecting variables related to social worker job response. Second, job stress, job attitude, and social support had multiple mediating effects. The parallel mediation effect and the serial mediation effect were verified. Third, job attitude was found to be a variable of multiple mediating effects. Fourth, job stress and social support were found to be double mediating effect variables. In response, programs and manuals suitable for the type of social welfare facilities and the policy basis for preparing countermeasures for social workers were limited, and follow-up studies on various variables were suggested.

• 한국보육지원학회지
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• 제19권5호
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• pp.21-43
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• 2023

Objective: The purpose of this study is to reduce job stress among child care teachers and enhance the quality of child care by examining the mediating effect of job stress in the relationship between positive psychological capital and the organizational commitment of child care teachers. Methods: The subjects of this study were 560 childcare teachers in Gyeonggi-do, and 465 questionnaires were ultimately analyzed. Descriptive statistics, correlation analysis, multiple regression analysis, and structural equation model were analyzed using SPSS 23.0 and AMOS 23.0. Results: As a result of the study, first, positive psychological capital of childcare teachers showed a positive correlation with organizational commitment. Additionally, both positive psychological capital and organizational commitment showed a negative correlation with job stress. Second, the direct effect of childcare teachers' positive psychological capital affecting organizational commitment was significant, and the direct effect of job stress affecting organizational commitment was also significant. It was found that positive psychological capital of childcare teachers significantly influenced organizational commitment through job stress. Conclusion/Implications: Therefore, providing an educational program to help childcare teachers enhance their positive psychological capital and foster commitment to the organization can significantly contribute to the improvement of childcare quality.

• 대한안전경영과학회지
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• 제16권3호
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• pp.389-397
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• 2014

This paper reviewed the relationship between job stress and service quality, and the moderating effect of organizational justice in food service restaurant. Based on the responses from 209 employees, the results of multiple regression analysis appeared as follow; 1) job stress(insufficient job control, lack of reward, occupational climate, job insecurity, interpersonal conflict) partly effect negatively on all service quality factors(tangibility. reliability, responsiveness, empathy). 2) distributive justice and procedural justice partly effect positively on the relationship between job stress and service quality.