• Journal of the Korean Data and Information Science Society
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• 제21권4호
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• pp.813-818
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• 2010

The least squares estimation method for model parameters under failure step-stress accelerated life tests is studied and a numerical example will be given to illustrate the proposed inferential procedures under the compound linear plans proposed as an alternative to the optimal quadratic plan, assuming that the exponential distribution with a quadratic relationship between stress and log-mean lifetime. The proposed compound linear plan for constant stress accelerated life tests and 4:2:1 plan are compared for various situations. Even though the compound linear plan was proposed under constant stress accelerated life tests, we found that this plan did well relatively in failure step-stress accelerated life tests.

• 한국응급구조학회지
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• 제24권1호
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• pp.103-115
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• 2020

Purpose: This descriptive study investigated the relationship between death awareness and life ethics awareness, according to life stress, among students in the department of paramedics. Methods: General characteristics were identified using means and frequency, and the differences between the two military models were analyzed using the χ²-test and t-test by dividing them into lower and higher groups based on the mean life stress score (99.76 points). Results: Those with high life stress had higher death awareness than those with low life stress at 114.11 points. In contrast, those with low life ethics experienced more severe life stress with a score of 145.61 points (t=-2.609, p=.010)(t=-2.953, p=.003). The death recognition attitude and bioethics according to the degree of living stress-showed a significant correlation between the low and high groups (r=.188, p=.043) (r=.201, p=.042). Conclusion: Paramedic students require education on how to cope with life stress. However, access to education is limited to people living in modern times. As a potential solution to this problem, observing videos on the Internet is recommended. Moreover, we suggest accessing Internet and smart phone applications for advertising/educational purposes.

• Journal of Ginseng Research
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• 제44권2호
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• pp.267-273
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• 2020

Background: Continuous exposure to high temperatures can lead to heat stress. This stress response alters the expression of multiple genes and can contribute to the onset of various diseases. In particular, heat stress induces oxidative stress by increasing the production of reactive oxygen species. The liver is an essential organ that plays a variety of roles, such as detoxification and protein synthesis. Therefore, it is important to protect the liver from oxidative stress caused by heat stress. Korean ginseng has a variety of beneficial biological properties, and our previous studies showed that it provides an effective defense against heat stress. Methods: We investigated the ability of Korean Red Ginseng and Korean black ginseng extracts (JP5 and BG1) to protect against heat stress using a rat model. We then confirmed the active ingredients and mechanism of action using a cell-based model. Results: Heat stress significantly increased gene and protein expression of oxidative stress-related factors such as catalase and SOD2, but treatment with JP5 (Korean Red Ginseng extract) and BG1 (Korean black ginseng extract) abolished this response in both liver tissue and HepG2 cells. In addition, JP5 and BG1 inhibited the expression of inflammatory proteins such as p-NF-κB and tumor necrosis factor alpha-α. In particular, JP5 and BG1 decreased the expression of components of the NLRP3 inflammasome, a key inflammatory signaling factor. Thus, JP5 and BG1 inhibited both oxidative stress and inflammation. Conclusions: JP5 and BG1 protect against oxidative stress and inflammation induced by heat stress and help maintain liver function by preventing liver damage.

• 한국치위생학회지
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• 제16권3호
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• pp.409-415
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• 2016

Objectives: The purpose of the study is to investigate the correlation between stress and oral health in some high school students. Methods: The subjects were 224 students from three high schools in Daejeon, Daecheon, and Incheon. from November to December, 2015. A self-reported questionnaire was filled out from November to December, 2015. The questionnaire consisted of general characteristics of the subjects, awareness toward stress, stress-coping pattern, oral health-related quality of life and oral health care. Data were analyzed by SPSS 18.0 program. Results: In the analysis of academic stress level by the general characteristics and stress level, higher stress group showed higher experience in stress expectation(high group 16.43, subgroup 9.21), internal stress(high group 13.97, subgroup 6.16), expression type stress(high 10.06, sub-4.95). The higher stress group had emotional stress management in stress-coping pattern and less experience in difficulty of tooth brushing, chewing discomfort, and oral health-related quality of life management(p<0.001). Conclusions: The stress had a negative impact on the oral health related quality of life. The high school students should be able to manage the physical and mental stress. It is necessary to provide the continuous oral health care management against the stress by the dental hygienists.

• 대한기계학회논문집A
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• 제29권2호
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• pp.341-349
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• 2005

Damage often occurs on the surface of railway wheel by wheel-rail contact fatigue. It should be removed before reaching wheel failure, because wheel failure can cause derailment with loss of life and property. The increase or decrease of the contact fatigue life by the metal removal of the contact surface were shown by many researchers, but it has not explained precisely why fatigue life increases or decreases. In this study, the effect of metal removal depth on the contact fatigue life for railway wheel has been evaluated by applying finite element analysis. It has been revealed that the residual stress and the plastic flow are the main factors determining the fatigue life. The railway wheel has the initial residual stress formed during the manufacturing process, and the residual stress is changed by thermal stress induced by braking. It has been found that the initial residual stress determines the amount of metal removal depth. Also, the effects of the initial residual stress and metal removal on the contact fatigue lift has been estimated, and an equation is proposed to decide the optimal metal removal depth for maximizing the contact fatigue life.

• 한국간호교육학회지
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• 제25권1호
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• pp.125-135
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• 2019

Purpose: This study was conducted to determine the mediator effect of social support in the association between stress for college life and depression among nursing students. Methods: The participants of the study were 201 university students in A and C cities. Self-report questionnaires were used to measure the variables. In the data analysis, the SPSSWIN 25.0 program was utilized for descriptive statistics, Pearson's correlation, Sobel test and multiple regression analysis. Results: Mean scores of stress for college life, depression and social support were 2.56, 4.12 and 0.61, respectively. Stress for college life and depression showed a significant positive correlation (r=.60, p<.001), while depression and social support showed a significant negative correlation (r=-.46, p<.001). Lastly, stress for college life and social support showed a significant negative correlation (r=-.55, p<.001). The analysis of the mediator effect of social support in the association between stress for college life and depression showed that social support had a significant mediator effect. Conclusion: Among nursing students, social support may be a mediator in the association between stress for college life and depression. Therefore, strategies for nursing intervention to improve social support should be developed for nursing students.

• 한국공작기계학회논문집
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• 제11권2호
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• pp.43-49
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• 2002

SB41 material is welded automatically and is investigated some effects of the welding residual stress in the growth and propagation of fatigue crack, so as to study the fatigue behaviour in the welding residual stress field. The summarized results are as follows; 1) In case of the load amplitude is constant, as the stress ratio is changing to 0.1, 0.33 and 0.5 the propagation life is constant but the growth life decreases. And than, when maximum load or minimum load is constant as the stress ratio increases the growth life and propagation life. 2) It was shown that fatigue crack propagation ratio da/dN was almost constant regardless of the stress ratio change at constant load amplitude and that the larger stress ratio, the slower was the fatigue crack propagation ratio. 3) The opening ratio U is influenced by $K_max$ but it isn't only the function of $K_max$ because data range is very large. 4) The fatigue life of the specimens on tensile compressive residual stress field was decreased and increased respectably more than that of the base metal.

• 한국보건간호학회지
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• 제30권3호
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• pp.470-482
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• 2016

Purpose: The purpose of this study was to investigate the moderated effects of coping strategies in the relationship between life stress and psychological well-being in university students. Methods: Self-report questionnaires were used to collect the data from 278 university students. The data were analyzed using descriptive statistics, pearson correlation coefficient and hierarchial multiple regression. Results: Psychological well-being is negatively associated with life stress and avoidance coping, and positively associated with problem solving coping. Results showed that there were significant moderated effects of coping strategies in the relationship between life stress and psychological well-being. Under high life stress levels with high problem solving coping and low avoidance coping, there was a high level of psychological well-being. Moreover, life stress and coping strategies interacted well with each other to affect psychological well-being. A negative correlation between life stress and psychological well-being was remarkable for the high problem solving coping group and high avoidance coping group. Conclusion: The study results suggest that in order to improve psychological well-being, it is necessary to provide intervention programs to promote problem solving coping and to reduce the avoidance coping for university students.

• 성인간호학회지
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• 제21권3호
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• pp.293-302
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• 2009

Purpose: This study is descriptive study that confirms the affect of the factors of perceived stress and social support of the kidney transplantation recipient affect on the quality of life. Mothods: 167 subjects who have received kidney transplantation in a university hospital in G city. Data obtained are analyzed by SPSS Win 13.0. Results: The perceived stress based on transplantation related characteristics and general traits of kidney transplantation has significant differences only in frequency of admission. The subjects who had been supported by acquittances have more significant social support index. The quality of life has significant differences in number of admissions, gender and occupation. Also, when the perceived stress of kidney transplantation recipients is lower and social support is higher, the quality of life is higher. The perceived stress has 28.1% increment of quality of life. Adding social support, both of them affect 34.8% increment of quality of life. Conclusion: To decrease the factor to cause the stress of kidney transplantation recipients, it is necessary to have social support networks and to develop plans and programs to increase the quality of life of recipients.

• The Journal of Korean Physical Therapy
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• 제22권2호
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• pp.69-75
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• 2010

Purpose: The purpose of this study was to investigate the relationship between subjective quality of life and job stress with regard to general characteristics and health characteristics of physical therapists (PTs) and occupational therapists (OTs). Methods: The study involved administering questionnaires to 93 PTs and OTs who worked in urban medical institutions between November 2009 and October 2009. A questionnaire (KvSBQOL) developed by Dunbar and colleagues and translated into Korean version by Yoon et al was used for measuring subjective quality of life. A questionnaire developed by Kim was used for measuring job stress. Results: Among PTs and OTs, the mean quality of life score was 3.10 points and the mean level of job stress was 3.42. Female PTs and OTs had significantly greater levels of job stress. Those PTs and OTs in the 'Lowest pay' group and in the 'Associated Degree' group reported the lowest quality of life. Those in the 'Very healthy' group of PTs and OTs had significantly lower job stress than the other groups. The group with the highest job stress had the lowest quality of life. A limitation of this study was that all data was self-reported and subject to associated bias. Conclusion: To prevent loss of business services by PTs and OTs, it is important to know how job stress affects quality of life. Our findings suggest that a reduction in job stress can improve quality of life among PTs and OTs.