• Journal of dental hygiene science
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• v.11 no.6
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• pp.553-562
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• 2011

This study was purposed to evaluate the level of occupational stress and the work-related factors of occupational stress in dental hygienists. The study was conducted during the period from May to October 2010 with study population consisted of 316 dental hygienists. The occupational stress was estimated with questionnaire of the Korean Occupational Stress Scale(KOSS) and the work-related factors were consisted with 9 work characteristics. Data analysis was performed with t-test, ANOVA and multiple regression analysis using SPSS(win ver 18.0) program. The level of occupational stress was $52.42{\pm}4.95$ in dental hygienists. The levels of sub-scales for occupational stress were $64.56{\pm}12.17$ in interpersonal conflict, $59.85{\pm}13.59$ in physical environment, $54.60{\pm}13.51$ in organizational system, $52.37{\pm}11.47$ in job demand, $51.71{\pm}10.58$ in lack of reward, $48.14{\pm}12.97$ in insufficient job control, $46.68{\pm}9.25$ in job insecurity, $41.46{\pm}15.98$ in occupational climate, respectively. According to multiple regression analysis, physical burden and daily repetitive working hour were work-related factors of occupational stress in dental hygienists. To conclude, the occupational stress in dental hygienists was higher than mean score of reference values of occupational stress in Korean workers and methods for reducing work load and work hours considering work characteristics of dental hygienist are needed to prevent occupational stress in dental hygienists.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.3
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• pp.207-216
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• 2004

This study was performed in oder to investigate to dietary behavior, perceived stress and their correlations of University students. The number of subjects was 549 and the results of this study are as followed: Only 13.9% of students-20% of male students, 10% of female students-exercise regularly. Regular exercise and health condition had no statistical relationship in this study. 83.9% of subjects had experience of alcohol drinking (19.4% of male students, 7.3% of female students). Many students replied that they drink alcohol 1∼2 times per a week. 24.4% of students-only 2.6% of female students-were smoking and great number of smokers were drinking also. The BMI of 46.7% of subjects were in normal range. 48.2% were in under weighted and 5.1% were in over weighted or obesity. The stress factor of University students were analyzed into 12. Inner stress factors like as identity, coursework, friendship, health problem were more potent in female students than male. Among the health related habits, disease itself had a great effect on many stress factors but regular exercise had a little.

• Korean Journal of Child Studies
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• v.28 no.3
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• pp.61-75
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• 2007

This study defined awareness of professionalism and job stress in 353 child-care teachers of children with special needs and analyzed the relative contribution of professional awareness to job stress. Teachers showed high awareness of 'ethics' and 'enthusiasm enhancing professionalism', and this awareness correlated highly with professionalism in the 'specialized knowledge and skills' sub-factors. Teachers showed high levels of stress in the 'general duty' and the 'guidance of children with special needs' categories, and this correlated highly with stress caused by 'child-care center management.' The results of canonical correlation analysis indicated that of professionalism sub-factors only the awareness of 'social services' contributed positively to job stress.

• Journal of Society of Preventive Korean Medicine
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• v.17 no.2
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• pp.79-88
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• 2013

Objectives : This study investigated the relationship between smoking and health factors including stress resistance, stress index, fatigue and vaso-aging degree. Methods : The subjects were 19,953 persons who had received health examination by Korean Medicine and submitted questionnaires about smoking history, for 8 months from March to November in 2011. The stress index and resistance, fatigue were measured by HRV(Heart Rate Variability). The vaso-aging degree were measured by APG(Accelerated Photoplethysmograph). Results : Regarding the relationship between smoking and stress index and resistance, fatigue and vaso-aging degree were significant differences(p<0.05). Conclusions : This study suggests that smoking affects health factors including stress, fatigue and avaso-aging degree.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.816-819
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• 2002

Accurate stress intensity factor analyses and crack growth rate of surface-cracked components in inhomogeneous materials are needed for reliable prediction of their fatigue lift and fracture strengths. This paper describes an automated system for analyzing the stress intensity factors of three-dimensional (3D) cracks in inhomogeneous materials. 3D finite element method (FEM) was used to obtain the stress intensity factor for subsurface cracks and surface cracks existing in inhomogeneous materials. To examine accuracy and efficiency of the present system, the stress intensity factor for a semi-elliptical surface crack in a plate subjected to uniform tension is calculated, and compared with Raju-Newman's solutions. Then the system is applied to analyze cladding effect of subsurface cracks in inhomogeneous materials. The results were compared with those surface cracks in homogeneous materials. It is clearly demonstrated from these analyses that the stress intensity factors for subsurface cracks are less than those of surface cracks.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.6
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• pp.95-103
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• 1998

Solutions of geotechnical engineering problems require calculation of deformation and stresses during various stages of loading. Powerful numerical methods are available to make such calculation even for complicated problems. To get accurate results, realistic stress-strain relationships of soil are dependent on a number of factors such as soil type, density, stress level and stress path. Attempts are continuously being made to develope analytical models for soils incorporating all such factors. The nature of stress-path dependency, the principle that governs deformations in sand, and the use of Lade's single work-hardening model for predicting sand response for a variety of stress-paths have been investigated and are examined. The test results and the analyses presented show that under some conditions sand exhibits stress-path dependent behavior. The strains calculated from Lade's single work-hardening model are in reasonable agreement with those measured, but some discrepancies occur. The largest difference between measured and calculated strains occurs for proportional loading with increasing stresses and for stress-path directions.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.401-413
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• 2022

This paper provides a simple method by which to estimate the cross-section stress profiles for nozzles designed according to ASME Code Section III. Further, this method validates the effectiveness of earlier work performed by the authors on standard nozzles. The method requires only the geometric information of the pressure vessel and the attached nozzle. A PWR direct vessel injection nozzle, a PWR outlet nozzle, a PWR inlet nozzle and a BWR recirculation outlet nozzle are selected based on their corresponding specific designs, e.g., a varying nozzle radius, a varying nozzle thickness and an outlet nozzle boss. A cross-section stress profile comparison shows that the estimates are in good agreement with the finite element analysis results. Differences in stress intensity factors calculated in accordance with ASME BPVC Section XI Appendix G are discussed. In addition, a change in the dimensions of an alternate nozzle design relative to the standard values is discussed, focusing on the stress concentration factors of the nozzle inside corner.

• Journal of the East Asian Society of Dietary Life
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• v.16 no.6
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• pp.655-662
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• 2006

This study was performed to investigate stress levels, dietary behaviors and food choices, and their correlations in college students. General characteristic stress scores, using a stress test, and the dietary behaviors and food choices of subjects under stress were measured in 358 subjects (185 males and 173 female). The mean total stress scores of the male and female students were $67.91{\pm}44.85$ and $85.62{\pm}48.91$, respectively. Female students were more stressed than males in relation to family, value, future, friends, and study related factors. There were gender differences in the food intake and frequency of eating sweet things when under stress. Stress increased the food intake and frequency of eating sweet things in female students. Especially, stress factors, such as value, economic, future, friends and study problems increased the food intake of female students. Female students preferred sweet tasting items; whereas, male students preferred hot tasting items when under stress. These results show the effect of life stresses on the dietary behaviors and food choices of college students. Stress not only increased energy consumption in certain individuals, but also changed their food choices. Therefore, education with regard to nutrition is necessary if college students are to practice good eating habits for the correct management of life stresses.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.2
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• pp.69-79
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• 1996

Dynamic stress intensity factors are derives when the crack is propagating with constant velocity under longitudinal shear stress in orthotropic disk plate. General stress fields of crack tip propagating with constant velocity and least square method are used to obtain the dynamic stress intensity factor. The dynamic stress intensity factors of GLV/GTV=1(=isotropic material or transversely isotropic material) which is obtained in out study nearly coincides with Chiang's results when mode Ⅲ stress is applied to boundary of isotropic disk. The D.S.I.F. of mode Ⅲ stress is greater when α(=angle of crack propagation direction with fiber direction) is 90° than that when α is 0°. In case of a/D(a:crack length, D:disk diameter)<0. 58, the faster crack propagation velocity, the less D.S.I.F. but when crack propagation velocity arrive on ghear stress wave velocity, the D.S.I.F. but when crack propagation velocity arrive on shear stress wave velocity, the D.S.I.F. unexpectedly increases and decreases to zero.

• Journal of Mechanical Science and Technology
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• v.18 no.5
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• pp.808-813
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• 2004

The stress analysis on orthotropic composite cylindrical shells with one circular or one elliptical cutout subjected to an axial force is carried out by using an analytical and experimental method. The composite cylindrical shell governing equation of the Donnell's type is applied to this study and all results are presented by the stress concentration factor. The stress concentration factor is defined as the ratio of the stress on the region around a cutout to the nominal stress of the shell. The stress concentration factor is classified into the circumferential stress concentration factors and the radial stress concentration factors due to the cylindrical coordinate of which the origin is the center of a cutout. The considered loading condition is only axial tension loading condition. In this study, thus, the maximum stress is induced on perpendicular region against axial direction, on the coordinate. Various cutout sizes are expressed using the radius ratio, (equation omitted), which is the radius of a cutout over one of the cylindrical shell. Experimental results are obtained using strain gages, which are attached around a cutout of the cylindrical shell. As the result from this study, the stress concentration around a cutout can be predicted by using the analytical method for an orthotropic composite cylindrical shell having a circular or an elliptical cutout.