• 아동학회지
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• 제31권2호
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• pp.135-150
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• 2010

This qualitative study explored the causes of student teacher stress during an early childhood teaching practicum and investigated the ways in which student teachers cope with this stress. Four student teachers in the same practicum placement were individually interviewed. The findings revealed that stress arose over a variety of concerns including both lack of professional knowledge related to the teaching practice and the challenges involved in establishing a positive relationship with their cooperating teacher, the parents and staff. The stress experienced by the student teacher was accompanied by physical symptoms such as exhaustion, fatigue, and the onset of vulnerability to colds. However, the students were found to be generally unsuccessful in managing their stress effectively. The results suggest that attempts to improve the practicum environment should be accompanied by academic interests and practical issues related to these stresses and that there is a clear need for programs designed to assist student teachers develop stress management skills.

• Journal of the Korean Data and Information Science Society
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• 제17권3호
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• pp.945-952
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• 2006

Several accelerated life test plans use tests at only two levels of stress and thus, have practical limitations. They highly depend upon the assumption of a linear relationship between stress and time-to-failure and use only two extreme stresses that can cause irrelevant failure modes. Thus 3-level stress plans are preferable. When the lifetime distribution of test unit is exponential with mean lifetime $\theta_i$ at stress $x_i$, i=0, 1, 2, 3, we derive the optimum quadratic plan under the assumption that a quadratic relationship exists between stress and log(mean lifetime), and propose the compound linear plans, as an alternative to the optimum quadratic plan. The proposed compound linear plan is better than two other compromise plans for constant stress testing and nearly as good as the optimum quadratic plan, and has the advantage of simplicity.

• Journal of Information Technology Applications and Management
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• 제27권6호
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• pp.15-29
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• 2020

Previous studies on the relationship between stress and performance have shown inconsistent results. Thus, this study focused on the effect of challenging stress among the two types of stress types and investigated the nonlinear relationship between the challenging stress and the performance. In particular, performance was divided into job performance, which is related to in-role behavior, and organizational citizenship behavior, which is characterized as extra-role behavior. Empirical results using 222 samples of Chinese workers have showed that challenging stress had a nonlinear relationship with job performance and organizational citizenship behavior. However, it was found that the shape of nonlinear relationship of the challenging stress on job performance and organizational citizenship behavior was slightly different. Finally, the theoretical and practical implications of this paper and future research directions are discussed.

• 건축사
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• 3호통권74호
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• pp.36-39
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• 1975

• 대한조선학회지
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• 제14권4호
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• pp.15-22
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• 1977

In this paper, two dimensional theoretical solutions of temperature distribution and thermal stress due to tandem cooling in an infinite plate were studied. Temperature distribution and thermal stress were calculated by numerical integration. Calculated temperature distributions were in good agreement with the result of the experiments by Park, and calculated thermal stresses were in good agreement with physical phenomena. This solutions could be applied to the practical tandem cooling operations.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 춘계학술대회논문집
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• pp.65-68
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• 1997

Vickers hardness is defined as indenting force per unit area indented by a pyramid-shaped diamond at the hardness test. It is well known that Vickers hardness has a direct relation with the flow stress of the strain-hardened material. This relation was theoretically investigated and the result was summerized in a form of algebraic equation in the last paper. In the present paper and experimental validation of this theoretical relation is given along with mathematical formulas for conversion of Vickers hardness into the flow stress in the strain-hardened material for practical use.

• 소성∙가공
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• 제11권4호
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• pp.355-362
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• 2002

In this study, an axi-symmetric finite element program for elastic analysis of the die set shrink fitted in cold extrusion was developed. The geometrical constraint according to shrink fit was enforced by employing the Lagrange multiplier method. The numerical results for strain and stress distributions in the die set including single and multi stress rings assembled by shrink fit were compared well with the Lame's equation for thick-walled solution available in the literature. To extend the applicability of the analysis program developed, various cases without or with stress ring and with pre-stress applied on stress ring were numerically investigated as well. This numerical approach enables the optimization study to determine optimal dimensions of die set to improve tool life for practical use in industry.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
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• pp.78-87
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• 1999

A mathematical model for the stress free surface profile in Over-Round and Round-Oval grove rolling, which can be used effectively in the calculation of pass area, is presented. The new model has generality, simplicity and accuracy for practical usage. The stress free surface profile of an outgoing stock can be modeled when the maximum spread of it known a priori. The equation for the stress free surface profile is formulated from the linear interpolation of the radius of curvature of an incoming stock and that of roll groove to the axis direction. In developing the analytical model, the effect of rolling temperature and friction between roll and work piece(stock) were not considered since the geometry of roll groove and the incoming work piece were assumed a dominant factor which decides the stress free surface profile of the outgoing stock. A simulation with the analytical model developed also has been carried out to demonstrate the stress free surface profile of the outgoing stock.

• 수산해양교육연구
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• 제28권4호
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• pp.1089-1097
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• 2016

The purpose of this study was to investigate the relationship between irrational beliefs and job stress in kindergarten teachers and explore specific irrational beliefs that influence kindergarten teachers' job stress. One hundred ninety one kindergarten teachers participated in the study and completed Job Stress Scale and General Attitude and Belief Scale. Collected data were analyzed using Pearson Correlation Coefficient Analysis and Multiple Regression Analysis. The major findings of the study were as follows: First, on the whole irrational beliefs were significantly positively related to job stress. Second, Although Self-Degradation and Demands for Fairness significantly predicted Kindergarten teachers' job stress, Self-Degradation were the most influential irrational belief. Finally the theoretical and practical implication of the results were discussed with the suggestion of future research.

• 한국철도학회논문집
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• 제7권4호
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• pp.319-325
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• 2004

In this study, analysis and design programs of bending of RC beams strengthened with fiber sheets are developed by using Visual Basic Language. The program consists two groups, ultimate strength method and nonlinear flexural analysis method. Ultimate strength method regards concrete compressive stress as a rectangular stress block and do not consider tensile stress of concrete and load-deflection curves. On the other hand, nonlinear flexural analysis considers tensile stress of concrete, load-deflection curves, state of stress distribution and failure strain of strengthening material. Also, the analysis method used in this study regards nonlinear flexural stress as compressive stress of concrete. This program can be a good tool for determining the bending strength of strengthened RC beams and estimating the amount of fiber sheets for practical use.