• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.92-96
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• 2005

Among the failure modes which can be occurred in tube hydroforming such as wrinkling, bursting or buckling, the bursting by local instability under excessive tensile stresses is irrecoverable phenomenon. Thus, the accurate prediction of bursting condition plays an important role in producing the successfully hydroformed part without any defects. As the classical forming limit criteria, strain-based forming limit diagram has widely used to predict the failure in sheet metal forming. However, it is known that the FLD is extremely dependant on strain path throughout the forming process. Furthermore, the path-dependent limitation of FLD makes the application to hydroforming process, where strain path is no longer linear throughout forming process, more careful. In this work, stress-based forming limit diagram (FLSD), which is strain path-independent and more general, was applied to prediction of forming limit in tube hydroforming. Combined with the analytical FLSD determined from plastic instability theory, finite element analyses were carried out to find out Ihe state of stresses during hydroforming operation, and then FLSD is utilized as forming limit criterion. In addition, the approach is verified with a series of bulge tests in view of bursting pressure and shows a good agreement. Consequently, it is shown that the approach proposed in this paper will provide a feasible method to satisfy the increasing practical demands for judging the farming severity in hydroforming processes.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.599-607
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• 2004

As buildings become more high-rise and lightweight in recent years, steel has been utilized more frequently. Based on the American AISC standard, all axial loads could be carried through a bearing load in a column splice, but according to Korean codes, the bearing load has constrained the stress that could be carried by only 25% of all axial loads. Thus, new column splice methods that use metal touch have been examined. In this study, the stress path mechanism, as an intermediation parameter in the gap's magnitude, must be determined. Similarly, the behavioral aspect of the metal touch connection must be sought after comparing and analyzing the results of the test.

• Journal of Families and Better Life
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• v.33 no.6
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• pp.1-14
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• 2015

The purpose of this study was to explore structural relationships among social support, parenting stress, self-perception and parenting behavior perceived by mother and provide preliminary data useful for desirable parenting behavior. For this purpose, the data of fourth wave Panel Study on Korean Children(PSKC) including social support, parenting stress, self-perception and parenting behavior measured by 1,746 mothers with 3-year-old children were analyzed. We identified structural relationships among the variables using SPSS 18.0 and AMOS 18.0 applying structural equation modeling. Measurement model and structure model had favorable goodness of fit and the results of structure models on each path were as follows. First, parenting behavior had positive correlations with social support and self-perception but there was a negative correlation between parenting behavior and parenting stress. Second, the relationship between social support and self-perception was mediated by parenting stress and parenting stress and self-perception mediated the relationship between social support and parenting relationship. In conclusion it is required to raise awareness about the importance of development of various parent education programs and parenting behavior.

• The Korean Journal of Emergency Medical Services
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• v.4 no.1
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• pp.73-81
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• 2000

This is a study to evaluate the effects of the stress and figure out the cause of them, I surveyed 400 students (male 257 and female 143) of health sciences colleges from 15th October to 23th October 1999. The major instruments of this study were Korean Style Self-Analysis Stress Opinionnaire. This Questionnaire contains 5 items which measure stress and health opinions or attitudes. The data were analyzed by the path analysis - with SPSS and AMOS package program. The result are as follows : 1. In the comparison of stress by sex, a potential group is highest for both of male and female (male 35.7%, female 64.3%). In high risk group, male is 10.6% and female 13.0%. In potential risk group, male is 4.1% and female 7.6%. 2. It have suggested that students' stress factors much affected with physical health and psychological health in school life(Y(Stress) = $0.813{\times}1$(Health) - $0.381{\times}2$(Mind Health) + $0.118{\times}3$(School Social) + $0.100{\times}4$(Confidence) - $0.061{\times}5$(Happiness Social)+E).

• Journal of the Korean Home Economics Association
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• v.37 no.6
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• pp.59-76
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• 1999

This study was to investigate casual relation of psychological well-being and quality of life of married couples. For the data set 434 married couples living in Pusan, Korea were chosen. The data were analyzed using M, SD, t-test, Pearson's correlation, multiple regression, and path analysis. The findings of this study are as follows; First, marital satisfaction and the level of quality of life are higher for husbands than wives. Whereas psychological distress is higher for wives than husbands. Second, for husbands, husband's level of education, job satisfaction, husband's housework participation, and job stress have significant effect on marital satisfaction. For wives, wife's level of education, husband's housework participation, and husband's job stress have significant effect on marital satisfaction. Third, for husbands, job satisfaction and job stress have significant effect on psychological distress. For wives, husband's job stress have significant effect on psychological distress. Fourth, for husbands, job stress, marital satisfaction and psychological distress have significant direct effect on quality of life. Besides, husband's age, husband's level of education, job satisfaction, job stress, husband's housework participation, and marital satisfaction are indirectly associated with quality of life. For wives, marital satisfaction and psychological distress have significant direct effect on quality of life. Besides, wife's level of education, husband's job stress, husband's housework participation, and marital satisfaction are indirectly associated with quality of life.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.7 no.1
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• pp.17-26
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• 2011

CANDU reactor core is composed a few hundreds pressure tubes, which support and locate the nuclear fuels in the reactor. Each pressure tube provides pressure boundary and flow path of primary heat transport system in the core region. In order to guarantee the structural integrity of pressure tube flaws which can be found by in-service inspection, crack growth and fracture initiation assessment have to be performed. Stress intensity factors are important and basic information for structural integrity assessment of planar and laminar flaws (e. g. crack). This paper reviews and confirms the stress intensity factor of axial crack, proposed in CSA N285.8-05, which is an fitness-for-service evaluation code for pressure tubes in CANDU nuclear reactors. The stress intensity factors in CSA N285.8-05 were compared with stress intensity factors calculated by three methods (finite element results, API 579-1/ASME FFS-1 2007 Fitness-For-Service and ASME Boiler and Pressure Vessel Code Section XI). The effects of Poisson's ratio and anisotropic elastic modulus on stress intensity factors were also discussed.

• Journal of the Korean Ceramic Society
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• v.33 no.1
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• pp.83-91
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• 1996

Monolithic AlN and AlN-W composites were fabricated by pressure-less sintering at 190$0^{\circ}C$ under nitrogen atmosphere and the influences of tungsten phase on the microstructure and mechanical properties were investi-gated. In the fabrication of sintered specimen no additive was used. And monolithic AlN showed substantial grain growth and low relative density. AlN-W composites were fully densified and grain growths of matrix were inhibited. The densification behavior of composites were inferred to be achieved through the liquid phase sintering process such as particle-rearrangement and solutino-reprecipitation. Also the oxid phases which is expected to form liquid phases duringsintering process were detected by XRD analysis. As the tungsten volume content increases fracture strength was decreased and fracture toughness was increased. It was suppo-sed that the strength decrease of composites with tungsten content was due to existence of interface phases. The subcritical crack growth behavior was observed from the stress-strain curve of composites. The effect of the secondary phase and interface phases on toughness in crease were studied through observation of crack propagation path and the influence of residual stress on crack propagation was investigated by X-ray residual stress measurement. In the result of residual stress measurement the compressive stress of matrix in composi-test was increased with tungsten volume content and the compressive stress distribution of matrix must have contributed to the inhibition of crack propagation.

• The Research Journal of the Costume Culture
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• v.23 no.2
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• pp.270-283
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• 2015

The purpose of this study was to investigate the relationship between working environment and quality of life of fashion vendor company workers by using working environment variables such as job stress, job burnout, job satisfaction, and turnover intention. Preliminary test was conducted by interviewing fashion vendor company workers in order to find out factors that were more suitable for their working environment. Main survey was conducted to 200 fashion vendor company workers and 194 responses were analyzed. The results of correlation analysis showed that job stress, job burnout, job satisfaction, turnover intention, and factors of quality of life had significant relationships. Boss stress, role stress, achivement decrease, and personal condition satisfaction showed a significant relationship with turnover intention. The results of path analysis showed that job stress had a positive relationship with job burnout and job burnout had a negative relationship with job satisfaction. Both job stress and job burnout had a positive relationship with turnover intention, whereas job satisfaction had a negative relationship with turnover intention. Also, the results showed that job burnout and turnover intention had a negative relationship with quality of life of fashion vendor company workers, whereas job satisfaction had a positive relationship with quality of life of fashion vendor company workers.

• Korean Journal of Psychosomatic Medicine
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• v.24 no.1
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• pp.109-116
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• 2016

Objectives : This study aimed to investigate the effects of resilience on posttraumatic stress symptoms and dissociation and whether depression mediates the relationships between resilience and posttraumatic stress symptoms and dissociation. Methods : A total of 115 firefighters participated in the study. Data were collected via the Life Events Checklist, Impact of Event Scale-Revised, Dissociative Experience Scale, Beck Depression Inventory, and Connor-Davidson Resilience Scale. Structural equation modeling and path analysis were applied to estimate the relationships between resilience, depression, posttraumatic stress symptoms, and dissociation. Results : Greater resilience was associated with lower posttraumatic stress symptoms and dissociation, and the relationship between them was fully mediated by depression. Conclusions : Specific aspects of depression may help explain the relationships between resilience and posttraumatic stress symptoms and dissociation. Tailored prevention programs and treatments based on resilience and depression may prevent posttraumatic stress symptoms and dissociation in firefighters and improve treatments outcomes among firefighters with posttraumatic stress symptoms and/or dissociation.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.4
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• pp.412-422
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• 2009

This study was conducted to assess exposure to musculoskeletal disorder(MSD) risk factors in hospital personnel who performed non-routinized work tasks. A tool ("PATH-KOSHA" version) was newly revised from PATH(Posture, Activity, Tools and Handling) method and uploaded into a personal digital assistant(PDA). The version was used, on a basis of direct-observation, to collect PATH data at the 2 hospital settings in different regions. Job analysis was performed to get various information (e.g., work and rest time, task type) as well. The data collected were visually checked for data cleaning and stored for future data analysis. A total of 1,992 PATH observations were made for 37 hospital workers. Exposure levels varied across 18 items of the MSD risk factors. The highest percent time spent on non-neutral postures was 53% for wrist deviation, followed by 47%(pinch grip), 35%(trunk posture), 23%(neck posture), and 20%(shoulder/arm posture). The highest percent time spent among hand activity level(HAL) variables was 55% for HAL-cat2 (HAL: 3.3 - <6.7). The percent time of items with respect to both loads with more than 5kg and contact stress was less than 4%. Vibration was not exposed in the study workers. Different aspects were discussed for findings. The study results showed that wrist deviation was highest in percent time spent on awkward posture while HAL-cat2 was highest in hand repetition. The study suggests that distal upper extremity posture and HAL should be primarily addressed and controlled in non-routinized work including the hospital settings.