• Ocean Systems Engineering
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• v.3 no.2
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• pp.97-122
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• 2013

For the optimization design and strength evaluation of the umbilical cable, the calculation of cross section stress is of great importance and very time consuming. To calculate the cross section stress under combined tension and bending loads, a new integrated analytical model of umbilical cable is presented in this paper. Based on the Hook's law, the axial strain of helical components serves as the tensile stress. Considering the effects of friction between helical components, the bending stress is divided into elastic bending stress and friction stress. For the former, the elastic bending stress, the curvature of helical components is deduced; and for the latter, the shear stress before and after the slipping of helical components is determined. This new analytical model is validated by the experimental results of an umbilical cable. Further, this model is applied to estimate the extreme strength and fatigue life of the umbilical cable used in South China Sea.

• The Journal of Korean Academic Society of Nursing Education
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• v.24 no.3
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• pp.269-278
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• 2018

Purpose: This study was conducted to investigate the correlation between stress and adjustment to college life among nursing students. Methods: The sample consisted of 183 university students in C & S cities. Self-report questionnaires were used to measure the variables. In data analysis, SPSSWIN 23.0 program was utilized for descriptive statistics, Pearson's correlation coefficients, and regression analysis. Results: The mean scores of stress and adjustment to college life were 2.55 and 3.24. Stress was significantly different according to grade (F=7.30, p<.001), economic state (F=14.39, p<.001), perceived health state (F=6.66, p<.001). In regression analysis, stress for college life, perceived health state, and college life satisfaction were significant predictors of adjustment to college life explaining 68%. Conclusion: This study suggests that perceived health state was a significant factor on adjustment to college life among nursing students. Therefore, the strategies of nursing intervention which improve perceived health state must be developed for college students.

• Geomechanics and Engineering
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• v.18 no.6
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• pp.627-638
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• 2019

Estimation of representative elementary volume (REV) of jointed rock masses is critical to predict the mechanical behavior of field-scale rock masses. The REV of jointed rock masses at site is strongly influenced by stress state. The paper proposed a method to systematically studied the influence of confining stress on the REV of jointed rock masses with various strengths (weak, medium and strong), which were sourced from the water inlet slope of Xiaowan Hydropower Station, China. A finite element method considering material heterogeneity was employed, a series of two-dimensional (2D) models was established based on the Monte-Carlo method and a lot of biaxial compressive tests were conducted. Numerical results showed that the REV of jointed rock masses presented a step-like reduction as the normalized confining stress increased. Confining stress weakened the size effect of jointed rock masses, indicating that the REV determined under uniaxial compression test can be reasonably taken as the REV of jointed rock masses under complexed in-situ stress environment.

• Korean Journal of Occupational Health Nursing
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• v.22 no.3
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• pp.191-197
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• 2013

Purpose: The purpose of this study was to identify the relationship of job stress, state of sleep, and depression and to identify factors influencing depression of emergency medical technicians. Methods: The research was a cross-sectional, descriptive study. Data collection were done using self-report questionnaires with 162 emergency medical technicians working in hospitals who agreed to participate in the study. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson's correlation coefficients and multiple regression with the SPSS/WIN 18.0 Program. Results: Depression had significant negative correlations with state of sleep, (r=-482, p<.001) and positive correlations with job stress (r=.196,p=.013). State of sleep had significant negative correlations with job stress (r=-.168, p=.033). The variance for life satisfaction was 23.7% (F=25.964, p<.001). Variable of state of sleep significantly predicted depression of emergency medical technicians. Conclusion: Considering these results, for emergency medical technicians' job stress, state of sleep, and depression, further studies are needed. Furthermore, there is a need to develop and implement new strategies to improve depression among emergency medical technicians.

• Geomechanics and Engineering
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• v.18 no.1
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• pp.21-27
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• 2019

Rockburst disasters pose serious threat to mining safety and underground excavation, especially in China, resulting in massive life-wealth loss and even compulsive closed-down of some coal mines. To investigate the mechanism of rockbursts that occur under a state of static forces, a stress model with sidewall as prototype was developed and verified by a group of laboratory experiments and numerical simulations. In this model, roadway sidewall was simplified as a square plate with axial compression and end (horizontal) restraints. The stress field was solved via the Airy stress function. To track the "closeness degree" of the stress state approaching the yield limit, an unbalanced force F was defined based on the Mohr-Coulomb yield criterion. The distribution of the unbalanced force in the plane model indicated that only the friction angle above a critical value could cause the first failure on the coal in the deeper of the sidewall, inducing the occurrence of rockbursts. The laboratory tests reproduced the rockburst process, which was similar to the prediction from the theoretical model, numerical simulation and some disaster scenes.

• Korean Journal of Psychosomatic Medicine
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• v.4 no.1
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• pp.124-137
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• 1996

As the society becomes more industrialized and modernized, we have more chances to experience a serious traumatic event. Post-traumatic stress disorder (PTSD) has 3 major categories of symptoms such as memory disturbance, hyperarousal and avoidance or numbness. I reviewed the psychobiological evidences in 3 main categories of symptoms and the biological treatment after a brief review of the epidemiology, psychosocial etiology and diagnosis of PTSD. The memory disturbance of PTSD might be developed by the potentiation of the memory pathway mediated by norepinephrine. PTSD induces HPA axis abnormality, it might also develop hippocampal dysfunction, which might contribute to the memory disturbance. The kindling effect develops desensitization, which might develop reexperiencing of the traumatic events and hyperarousal state. Chronic aroused state of locus ceruleus with resultant chronic maladaptive state of norepinephrine system, might develop hyperarousal state. Social avoidance and physical numbing state in PTSD might be caused by serotnin or opiate system. Stress induced analgesia might be developed by opiate reliesed against the acute stress. The biologic research results would help the selective treatment of PTSD.

• Journal of the Korea Society of Computer and Information
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• v.22 no.6
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• pp.87-93
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• 2017

In this paper, we design a small low power single channel ECG(Electrocardiogram) system of Chest Belt type with fiber-type electrodes to measure emotional state change of game addict. HRV(Heart Rate Variability) is analyzed through heart rate signal measurement and the psychological stress state is judged by using it. And it verifies its effectiveness through prototype. First, we design HR measurement module through low power MCU(Micro Controller Unit) and implement prototype level measurement system. The results showed that the difference between the addiction group and the general group was confirmed and that the system was effective. The result of this study can be used for health management such as reduction of stress of the user through music and breathing that lowers the stress by detecting the stress state of the general person or the chronic ill person.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.76-79
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• 2000

Polymeric composites exhibit highly nonlinear and rate dependent behavior during loading and unloading in off-axis directions. The equilibrium state of stress during loading is lower than the state of stress produced at finite strain rates. The amount of stress relaxation during loading decreases. Interestingly, however, the stress goes up to reach to the equilibrium state of stress for a fixed displacement during unloading. The unloading behavior is quite similar to the loading behavior. The stress relaxation patterns during loading and unloading is also similar, and those depend on the fiber orientation angles and the loading and unloading rates. The AS4/PEEK thermoplastic composite is used to characterize the relaxation behavior for different off-axis angles and loading rates. There exists a transient loading region at the beginning of unloading. The effective stress and effective plastic strain concept is used to establish a master curve of stress recovery pattern for different off-axis angles and unloading rates.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.1
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• pp.171-180
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• 2007

Reliability analysis of prestressed steel and concrete(PSSC) girders is conducted for deflection, stress and moment strength limit state. PSSC girder has strong advantages in terms of construction cost and vertical clearance for the span length of over 40 meters. In this paper, example PSSC girders with different span lengths, section dimensions and design stress levels are designed and analyzed to calculate the midspan deflection, stress and the section moment strength. Deflection limit state, stress limit state and strength limit state functions are assumed and the reliability indexes are obtained by Monte-Carlo simulation and Rackwitz-Fiessler procedure. The results show that the reliability of PSSC girder for deflection limit state is appropriately higher than the stress limit state and the reliability for moment strength is significantly conservative.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.475-476
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• 2007

The stress induced leakage currents will affect data retention in synapse transistors and the stress current, transient current is used to estimate to fundamental limitations on oxide thicknesses. The synapse transistor made by thin silicon oxides has represented the neural states and the manipulation which gaves unipolar weights. The weight value of synapse transistor was caused by the bias conditions. Excitatory state and inhibitory state according to weighted values affected the channel current. The stress induced leakage currents affected excitatory state and inhibitory state.