• Transactions of Materials Processing
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• v.3 no.2
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• pp.215-228
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• 1994

The purpose of this paper is to pursue a general method to determine both the flow stress of a material and the friction factor by ring compression test. The materials are assumed to obey the expanded n-power hardening rule including the strain-rate effect. Ring compression is simulated by the rigid-plastic finite element method to obtain the database used in determining the flow stress and friction factor. The Simulation is conducted for various strain hardening exponent, strain-rate sensitivity, friction factor, and compressing speed, as variables. It is assumed that the friction factor is constant during the compression process. To evaluate the compatibility of the database, experiments are carried out at room and evaluated temperature using specimens of aluminum 6061-T6 under dry and grease lubrication condition. It is shown that the proposed test method is useful and easy to use in determining the flow stress and the friction factor.

• Structural Engineering and Mechanics
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• v.5 no.3
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• pp.239-256
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• 1997

The companion paper presents a new three-parameter model for the uniaxial rate-sensitive material response, which is based on a bilinear static stress-strain relationship with kinematic strain-hardening. This paper extends the proposed model to trilinear static stress-strain relationships for steel and concrete, and discusses the implementation of the new models within an incremental-iterative solution procedure. For steel, the three-parameter rate-function is employed with a trilinear static stress-strain relationship, which allows the utilisation of different levels of rate-sensitivity for the plastic plateau and strain-hardening ranges. For concrete, on the other hand, two trilinear stress-strain relationships are used for tension and compression, where rate-sensitivity is accounted for in the strain-softening range. Both models have been implemented within the nonlinear analysis program ADAPTIC, which is used herein to provide verification for the models, and to demonstrate their applicability to the rate-sensitive analysis of steel and reinforced concrete structures.

• Journal of the Korean Society of Safety
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• v.29 no.3
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• pp.136-142
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• 2014

Recently a new version of PRO-LOCA program was released. Using the program, failure probability of pipes can be evaluated considering fatigue and/or stress corrosion crack growth and the effects of various parameters on the integrity of pipes in nuclear power plants can be evaluated quantitatively. The analysis results can be used to establish an inspection plan and to examine the effects of important parameters in a maintenance plan. In this study, sensitivity analyses were performed using the program for several important parameters including sampling method, initial crack size, number of initial fabrication flaws, operation temperature, inspection interval, operation temperature and nominal applied bending stress. The effect of parameters on the leak and rupture probability of pipes was evaluated due to fatigue or stress corrosion crack growth.

• Human Ecology Research
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• v.53 no.6
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• pp.595-604
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• 2015

This study analyzes child variables (child's temperament and child's depression) and parent variables (spouse support, social support, and job satisfaction) associated with married nurse parenting stress and provides data that can assist institutional support mechanisms. The research targeted 232 nurses at five general hospitals in Seoul, Gyeonggi-do, Jeolla-do, Chungcheong-do with elementary children. Data were analyzed using t-test, Pearson correlation analysis, and hierarchical regression analysis. The results of the study were as follows. First, there were significant correlations in parenting age, child number and parenting stress for mothers. Second, married nurses with high sociality of temperament, low sensitivity of temperament, and high activity of temperament child as well as married nurses with spouse support, social support, job satisfaction saw a reduction in high levels of parenting stress. Third, the results of this study showed that child depression, sensitivity of temperament, spouse support, and job satisfaction were factors to understand married nurses parenting stress. Child depression was an important factor to understand married nurses parenting stress. The results indicated variables affecting parenting stress of married nurses and suggested directions for the social welfare system.

• The Journal of Korean Obstetrics and Gynecology
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• v.36 no.2
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• pp.85-100
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• 2023

Objectives: To evaluate stress patterns and coping abilities in women with infertility by conducting in-depth interviews. Methods: Ten women with infertility who visited the Korean Medicine Hospital and provided consent after being informed of the purpose and method of the study were selected after meeting the inclusion/exclusion criteria. They were requested to complete a preliminary questionnaire developed by the researchers, the Infertility Stress Scale, and the Korean version of the Fertility Problem Inventory (FPI). Subsequently, each participant was interviewed individually. Results: The preliminary questionnaire was used to evaluate sensitivity to each type of infertility-related stress and ability to express and resolve it. Among all infertility stress types, the largest proportion, accounting for an average of 47.5±26.95%, was that felt by the patient herself. Considering stress awareness intensity, the stress felt by the patient was the highest, with an average score of 4.30±0.64. Relative stress sensitivity due to infertility was the highest, with an average score of 3.90±0.94. Compared with general work stress, the average ability to relieve stress related to problems with spouses was the highest, with a score of 2.50±1.20. The average Infertility Stress Scale score was 2.88±1.35 and FPI score was 2.87±2.52. Conclusions: The highest stress scores were observed for the following items: meaning of children, need for parenthood, and stress due to the diagnosis of infertility. The lowest stress scores were allocated to the item concerning relationships with friends and co-workers. Based on the in-depth interviews conducted after the survey, stress in women with infertility may be classified as emotional, physical, and economic. Thus, the requirement for providing appropriate psychological and emotional support depending on the stress type in addition to general medical treatment for infertility treatment was confirmed.

• Computational Structural Engineering
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• v.11 no.1
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• pp.161-170
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• 1998

A general formulation of the long cylinder tolerance design for the joint structure is here presented. The aim of this paper is to calculate the tolerance of joint by defining tolerance as a kind of uncertainty and to obtain the robustness of the joint structure. It is formulated on the bases of the minimum sensitivity theorem. The objective function is the tolerance sensitivity for the Von-Mises stress. It also took into full account the stress, displacement and weight constraints. PLBA(Pshenichny-Lim-Belegundu-Arora) algorithm is used to solve the constrained nonlinear optimization problem. The finite element analysis is performed with CST(Constant-Strain-Triangle) axisymmetric element. Sensitivities for design variables are calculated by the direct differentiation method. The numerical result is presented for the cylindrical structure where the joint tolerance is treated as random variables.

• Korean Journal of Optics and Photonics
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• v.8 no.5
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• pp.415-419
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• 1997

A novel fiber optic sensor is demonstrated using a FBG in PM(Polarization-Maintaining) fiber. Gratings have been written in a Bow-Tie type fiber using the phase mask. The operation of the sensor simply involves monitoring back-reflected Bragg wavelengths from the grating. Since PM fiber has two principal semi-axes with two indices of refraction, two Bragg wavelengths were observed. We have observed the position of Bragg wavelengths for PM FBG shifted simultaneously by either applying the longitudinal strain or temperature change. The wavelength sensitivity of 1.2pm/$\mu$$\varepsilon$ about a longitudinal strain and the wavelength sensitivity of 11.4pm/$^{\circ}C$ about a temperature have been experimentally achieved. The wavelength sensitivity of both longitudinal strain and temperature are approximately same with the reported values for the single mode FBG. On the other hand, the change of separation between Bragg wavelengths was observed by the applying transverse stress. We observed that the separation between two Bragg wavelengths is proportional to the applied transverse stress. The wavelength sensitivity of 14.6 pm/N about a transverse stress has been achieved. We have demonstrated PM FBG sensors can measure the transverse stress independently from the effects of temperature.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.3
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• pp.215-222
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• 2017

In order to evaluate a stress state of concrete according to the change of tensile force of prestressed beam, improved nonlinear resonant ultrasonic spectroscopy(NRUS) method is proposed. This technique is advantageous to evaluate the stress state in initial state because the method shows much higher sensitivity than existing linear ultrasonic methods. The NRUS technique measure a nonlinearity parameter, which is calculated from the resonant frequency shift of ultrasonic wave related to the medium state, and the result is also closely related to the stress state of concrete. In this study, the nonlinearity parameter was measured with the change of tensile force to verify the close relationship between the two factors, and the effect of repetitive load cycle on the change of nonlinearity parameter was analyzed. In addition, sensitivity comparison with the linear ultrasonic pulse velocity method was performed. Through the experimental results, the possibility of NRUS technique for the evaluation of stress state in prestressed beam was confirmed.

• Journal of Community Nutrition
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• v.8 no.4
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• pp.185-192
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• 2006

This study was performed to investigate factors affecting sensitivity and preference for salty tastes of Korean adult females. Sensitivity and preference for salty tastes were determined as detection threshold concentration of NaCl solution and the optimally-preferred NaCl concentration of the bean sprout soup, respectively. A self-administered questionnaire was used to obtain the information regarding general characteristics, self diagnosis of stress, health-related lifestyle practices, dietary habits and food preferences. Dietary intake using 24-hours recall and blood pressure were measured. Salty taste detection thresholds and optimally-preferred NaCl concentrations were 0.0197% and 0.357%, respectively. There was a significant positive correlation between the optimally-preferred salt concentration and age, despite no significant correlation between either sensitivity or preference for salty taste and sodium intake, which was 3,605mg/day. Those who had bread or cereal with milk as breakfast instead of a traditional Korean meal and those who preferred jjigae to soup had significantly higher NaCl preferences for bean sprout soup. Going to bed after midnight and skipping meals (${\geq}3/week$) decreased salty taste sensitivity without reaching statistical significance. Self awareness of one's own health, recent weight changes, family history of hypertension, sleep quality, getting-up time, rate of eating and other food preferences did not affect either perception. Stress level, TV watching, BMI and sodium intake did not have significant correlation to sensitivity or preference. Further research including a large number of well-controlled subjects and more accurate measurement of sodium intake should be directed to find other factors affecting salt preference and sensitivity in order to decrease Na intake and related diseases.

• Cartoon and Animation Studies
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• s.33
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• pp.403-423
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• 2013

Video images of emotional happiness or unhappiness, stress or emotional division of tranquility in the form of a tree is evaluated by weighting. Representative evaluation of the video image brightness contrast sensitivity ratings 1 car happy, unhappy or nervous, calm and refined with two car dependency, sensitivity to visual images are separated. Emotion Recognition of four compared to the numerical data is measured by brightness. OpenCV implementation through evaluation graph the stress intensity contrast, tranquility, happiness, unhappiness with changes in the value of four, separated by sensitivity to computing. Contrast sensitivity of computing the brightness according to the input value 'unhappy' to 'happy' or 'stress' to 'calm' the emotional changes are implemented. Emotion computing the regularity of the image to calculate the sensitivity localized computing system can be controlled according to the emotion of the contrast value of the brightness changes are implemented. The future direction of industry on the application of emotion recognition will play a positive role.