• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.05a
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• pp.122-126
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• 2000

In particle or short-fiber reinforced composites cracking of the reinforcements is a significant damage mode because the broken reinformcements lose load carrying capacity . The average stress in the inhomogeneity represents its load carrying capacity and the difference between the average stresses of the intact and broken inhomogeneities indicates the loss of load carrying capacity due to cracking damage. The composite in damage process contains intact and broken reinforcements in a matrix, An incremental constitutive relation of particle or short-fiber reinforced composites including the progressive cracking damage of the reinforcements have been developed based on the Eshelby's equivalent inclusion method and Mori-Tanaka's mean field concept. influence of the cracking damage on the Eshelby's equivalent inclusion method and Mori-Tanaka's mean field concept. Influence of the cracking damage on the stress-strain response of the composites is demonstrated.

• Journal of Aerospace System Engineering
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• v.15 no.6
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• pp.19-25
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• 2021

This paper presents a method that uses the stress failure criteria to predict the tensile failure strength of open-hole laminates with stress concentrations. The composite material used in this study corresponds to a 177 ℃ cured, carbon/epoxy unidirectional tape prepreg. The results obtained by testing ten different laminates were compared and analyzed to verify the tensile strength of the open-hole laminates predicted using the proposed stress failure criteria. The findings of this study confirm that the tensile strength predictions performed using the proposed method are generally accurate, except in cases involving highly soft laminates (10% of 0° ply).

• Korean Journal of Occupational Health Nursing
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• v.18 no.2
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• pp.232-241
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• 2009

Purpose: This study was conducted to estimate the job stress and depression of female and male service workers and to determine the predictors influencing depression. Method: In this cross-sectional study, the data were collected from hotel, wholesale, and insurance companies. A total of 244 workers were recruited. Among them, 118 were female workers. A self-administered questionnaire was consisted of personal characteristics, job stress, daily life stress, social support, and depression. Depression was measured using a CES-D Korean version. Result: The average job stress of female workers was higher than that of male workers (P<.05). The average depression scores of female workers were higher than those of male workers, but the difference was not statistically significant. Multiple regression analysis showed that role conflict and low social support were significant predictors of depression in female workers. In male workers, role conflict, low social support, and under-utilization of abilities were significant predictors of depression. Conclusion: The results of this study suggest that depression of service workers may be prevented by creating a workplace environment that focuses on role conflict and social support. Also, health providers should consider the vulnerability of working women to job stress.

• Journal of Korean society of Dental Hygiene
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• v.3 no.2
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• pp.101-116
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• 2003

The purpose of this study was to identify the personality type and stress coping method of students of Dept. dental hygiene students and relationship between them. Second purpose of this study was to suggest the good and useful method of stress coping. Data was drawn from a convenient sample of 350 and 3rd year students of the department of dental hygiene, some college located in Kyung-Ki Province. The results were analyzed with SPSS 10.0 and the conclusion is as follow: 1. The average of Machiavellism type is 3.30, which indicates that most of the students has a middle type(80%). In the A/B type, most of the students has B type(46.7%). In the score of externality and internality, externality(62.6%) is higher than internality(20.3%) 2. As a result of investigating how they coped with stress, the direct coping was utilized most and the physical was utilized least. 3. In the relation between the personality type and stress coping method, non-Machiavellism type has a statistically significant difference, in the direct coping and destructive coping.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.25 no.4
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• pp.293-300
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• 2018

Purpose: This study was done to identify the relationship between nurses' compliance with safety guidelines for the use of antineoplastic agents, observable symptoms, and stress from occupational exposure. Methods: The participants were 172 nurses from six general hospitals in a metropolitan area. They had administered antineoplastic agents at least three months prior to the study. Data were collected using self-report questionnaires, and then analyzed using SPSS/WIN 23.0 for descriptive statistics, t-test, one-way ANOVA, $Scheff\acute{e}$ method, and Pearson correlation coefficient. Results: The average score on the guideline for safety compliance was 87.75 points out of a total of 100. The average score for observable symptoms of exposure to antineoplastic agents was 30.12 (28~56) points, and that for mean stress was 33.52 (15~60) points. Observable symptoms and stress from occupational exposure showed a statistically significant positive correlation (r=0.34, p<.001). Conclusion: To increase the degree of compliance with safety guidelines for antineoplastic agents, hospitals should lower the chance of exposure to antineoplastic agents, as well as minimize the observable symptoms and stress from occupational exposure. Periodic education and policy support are needed to improve compliance with safety guidelines for antineoplastic agent use.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.481-486
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• 1997

In the paper, a simplified method for nonlinear analysis of reinforced concrete structures is presented, which is based on timeoshenko beam theory and constitutive equations that are given by the relation of average stress and average strain for concrete and reinforcing bars. Especially, this method consider shear deformation and determine the failure mode. In this paper, 1-D beam element model and program considering shear deformation are suggested. In addition, program procedure is presented briefly and the results are plotted with test examples.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.287-292
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• 1998

In particle or short-fiber reinforced composites. cracking of the reinforcements is a significant damage mode because the broken reinforcements lose load carrying capacity. This paper deals with the load carrying capacity of intact and broken ellipsoidal inhomogeneities embedded in an infinite body and a damage theory of particle or short-fiber reinforce composites. The average stress in the inhomogeneity represents its load carrying capacity. and the difference between the average stresses of the intact t and broken inhomogeneities indicates the loss of load carrying capacity due to cracking damage. The composite in damage process contains intact and broken reinforcements in a matrix. An incremental constitutive relation of particle or short-fiber reinforced composites including the progressive cracking damage of the reinforcements have been developed based on the Eshelby's equivalent inclusion method and Mori and Tanaka's mean field concept. Influence of the cracking damage on the stress-strain response of the composites is demonstrated.

• Journal of Power Electronics
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• v.12 no.3
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• pp.410-417
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• 2012

In this paper, a direct current control method based on a one-cycle controller (DCOCC) for double frequency buck converters (DF buck) is proposed. This control method can make the average current through the high frequency and low frequency inductors of a DF buck converter equal. This is similar to the average current control method. However, the design of the loop compensator is much easier when compared with the average current control. Since the average current though the high frequency and low frequency inductors is equivalent, the current stress of the high frequency switches and the switch losses are minimized. Therefore, the efficiency of the DF buck converter is improved. Firstly, the operation principle of DCOCC is described, then the small signal models of a one cycle controller and a DF buck converter are presented based on the state space average method. Eventually, a system block diagram of the DCOCC controlled DF buck is established and the compensator is designed. Finally, simulation and experiment results are given to verify the correction of the theory analysis.

• Journal of Korean Academy of Nursing Administration
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• v.13 no.2
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• pp.184-190
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• 2007

Purpose: This study was undertaken in order to suggest self-leadership as a method for nurses to lower their job stress and enhance their job satisfaction. So the relations among self-leadership, job stress and job satisfaction were studied. Method: The subjects of study were 123 nurses who have been working in 2 general hospitals located in K city. The data were collected by Q & A and analyzed using descriptive statistics, Pearson's correlation coefficient, t-test, and ANOVA on SPSS Program. Result: Nurses got average 3.50, 2.64 and 3.12 points out of 5 in their self-leadership, job stress and job satisfaction respectively. The self-leadership was negatively correlated with job stress (r=-.429, p=<.001) while it is positively correlated with job satisfaction(r=.281, p=<.001). And job stress was negatively correlated with job satisfaction(r=-.574, p=<.001). Job stress had statistically significant differences according to age and marital status. Conclusion: In conclusion self-leadership is correlated with job stress and job satisfaction. It is recommend that hospital managers have to develop methods which enhance self-leadership of nurses.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.3 s.22
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• pp.9-16
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• 2006

In structural health monitoring, the safety of structural members are assessed by the level of stress measured by various strain sensors based on different sensing mechanisms. Since most existing strain sensors used for health monitoring system can cover a relatively small range of structural members, it is very difficult to measure the maximum value of the member subjected to varying amount and types of loads with those point sensors. The reliability of assessed safety of a member may be improved by increasing the number of sensors. It may not be also realistic to increase the number of sensors to overcome these drawbacks. In this paper, a stress measuring method for beam-column members is developed by estimating the maximum stress based on the average strains obtained from long gauge sensor. The average strain from long gage fiber optic sensor is transformed into the maximum strain by multiplication of the modification factor derived in this research.