• International Journal of Railway
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• v.8 no.1
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• pp.5-9
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• 2015

Reliability based limit state design method is replacing traditional deterministic designs such as allowable stress design and/or ultimate strength design methods in world trends. European design code(Eurocode) has adopted limit state design, and Korea road bridge design standard has also recently been transferred to limit state design method. In this trend, Korea railroad design standard is also preparing for adopting the same design concept. While safety factors are determined empirically in traditional design, load combinations as well as load factors are determined by solving limit state equations. General partial safety factors are evaluated by using AFORM(Advanced First Order Reliability Method) in the reliability based limit state design method. In this study sensitivity analysis is carried out for a dead load factor and a live load factor. Relative precisions of the dead load and the live load factors are discussed prior to the AFORM analysis. Furthermore the sectional forces of design and the material quantities required by two different design methods are compared for a PSC box girder railway bridge.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.343-356
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• 2022

As a part of round robin analysis to develop a finite element elastic-plastic seismic analysis procedure for nuclear safety class 1 components, a series of parametric analyses was carried out on the simulated pressurizer surge line system model to investigate sensitivity of the analysis results to finite element analysis variables. The analysis on the surge line system model considered dynamic effect due to the seismic load corresponding to PGA 0.6 g and elastic-plastic material behavior based on the Chaboche combined hardening model. From the parametric analysis results, it was found that strains such as accumulated equivalent plastic strain and equivalent plastic strain are more sensitive to the analysis variables than von Mises effect stress. The parametric analysis results also identified that finite element density and ovalization option in the elbow elements have more significant effect on the analysis results than the other variables.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.1
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• pp.23-41
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• 2023

Coupled thermo-hydraulic-mechanical (THM) processes are essential for the long-term performance of deep geological disposal of high-level radioactive waste. In this study, a numerical sensitivity analysis was performed to analyze the effect of rock properties on THM responses after the execution of the heater test at the Kamaishi mine in Japan. The TOUGH-FLAC simulator was applied for the numerical simulation assuming a continuum model for coupled THM analysis. The rock properties included in the sensitivity study were the Young's modulus, permeability, thermal conductivity, and thermal expansion coefficients of crystalline rock, rock salt, and clay. The responses, i.e., temperature, water content, displacement, and stress, were measured at monitoring points in the buffer and near-field rock mass during the simulations. The thermal conductivity had an overarching impact on THM responses. The influence of Young's modulus was evident in the mechanical behavior, whereas that of permeability was noticed through the change in the temperature and water content. The difference in the THM responses of the three rock type models implies the importance of the appropriate characterization of rock mass properties with regard to the performance assessment of the deep geological disposal of high-level radioactive waste.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4A
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• pp.719-726
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• 2006

The use of CWR track not only reduces the track maintenance cost, but increase the life cycle of track components. Therefore, the use of the CWR track has increased consistently in the worldwide. As the use of CWR increases in track structures, derailing disasters associating with track buckling also increase in great numbers due to high compressive thermal stress in the summer. Among many CWR parameters, the influence of the sectional properties of the rail was investigated on the stability of CWR track in this study. Also, the sensitivity of the broken fastener and the stiffness of the fastener system such as the translational and rotational stiffness was investigated.

• Korean Journal of Adult Nursing
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• v.22 no.4
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• pp.418-429
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• 2010

Purpose: This study was performed to identify the relationship between Sense of Humor, Coping Humor, Perceived stress and self-esteem in the middle-aged women. Methods: Data were collected from the 20th of June to the 30th of August in 2009 from 145 middle-aged women living in Seoul. Data analysis was done with SPSS/WIN 12.0 program for descriptive statistics and Pearson correlation. Results: The mean score of the humor sense was $55.94{\pm}6.52$, coping humor was $21.11{\pm}3.82$, perceived stress was $22.21{\pm}3.03$ and self-esteem was $27.50{\pm}2.88$. Subcategories of sense of humor were that emotional expressiveness was average $20.75{\pm}2.70$, meta-message sensitivity was average $20.12{\pm}2.74$ and liking of humor was average $15.13{\pm}3.44$. Sense of humor was difference according to the economic status(t=2.000, p=.047), coping humor was difference according to the on medication use(t=2.227, p=.027). There was a significant correlation between the coping humor, perceived stress and the self-esteem. When the coping humor was higher, perceived stress was lower and the self-esteem was higher. Conclusion: This study showed that medication and economic status influences the humor scores and the sense of humor and coping humor were related to perceived stress and self-esteem in middle-aged women Therefore, these findings can provide the basis for the development of nursing intervention to increase the ability to coping with stress.

• The Korean Journal of Emergency Medical Services
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• v.12 no.3
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• pp.5-15
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• 2008

Purpose : This study is a descriptive research to provide basic factors of posttraumatic stress in Firefighters. This study was carried out to develop the effective program for the fire fighters to cope with the posttraumatic stress following the disasters. Methods : The questionnaires were collected among fire fighters who serviced in K and I community from April 1 to June 30 in 2008. Total 304 questionnaires were analyzed by SPSS WIN program for descriptive statistics, Pearson's correlation coefficient and t-test. Results : 1. 48.0% of 300 fire fighters were at the age of 31-40, and 42.3% were under 30. 2. Work burden had a significant difference of 2.30 in low-risk group, 2.60 in high-risk group(t-value=-3.85, p=0.00). However, life event had no significant difference 0.79 event in low-risk group, 1.41 event in high-risk group(t-value=-2.27, p=0.24). 3. Concerning posttraumatic stress factors, there was positive correlation between mobilization impact level r=0.38(P<0.01), work burden r=0.38(p<0.01), and life event r=0.27(p<0.01). 4. According to the Symptom Check List-Revised(SCL-90-R), somatization had a significant differences(t-value=5.46, p=0.00), obsessive-compulsive(t-value=7.16, p=0.00), interpersonal sensitivity(t-value=6.15, p=0.00), depression(t-value=6.62, p=0.00), anxiety (t-value=7.33, p=0.00), hostility(t-value=5.94, p=0.00), phobia anxiety(t-value=6.85, p=0.00), paranoid ideation(t-value=5.55, p=0.00), psychotism(t-value=6.52, p=0.00) in low-risk and high-risk group. Conclusion : As a consequence, mobilization impact, work burden, and life event were the influential factors on posttraumatic stress. Also, high-risk group revealed significantly higher score on all 9 scales. The information obtained from surveys made recommendation to develop the intervention of stress management to control mobilization impact and posttraumatic stress.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.423-426
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• 2011

The excessive axial load occurred in an immovable zone of continuous welded rail(CWR) tracks threatens the security of running trains due to the track buckling in extreme hot summer. The influence factors, such as rail temperature for compressive stress, ballast resistance for track stiffness and initial imperfection of track for tracks irregularity are uncertain track parameters that are randomly varied by climate conditions, operating conditions and maintenance of track etc. So, buckling of CWR tracks has very high uncertainties. Therefore, applying the probabilistic approach method is essential in order to rationally consider the uncertainty and randomness of the various parameters. In this study, buckling sensitivity analysis was carried out with respect to the characteristics of probability distribution of lateral ballast resistance using the buckling probability evaluation system of CWR tracks developed by our research team.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.2
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• pp.537-543
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• 1991

In this study, the strain rate effects are considered in the formulation by introducing the constitutive equation of the strain rate sensitive materials and rigid-viscoplastic finite element program is developed for axisymmtric extrusion. The effect of strain rate sensitivity on the flow characteristics and forming pressure are investigated and the experiments are carried out for extrusion with pure lead specimens. The theoretically predicted forming pressure showed reasonably good agreement with the experimental values.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.758-761
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• 2003

The goal of the research is to study and describe a new stressed state of High Temperature Superconducting (High-T$_{c}$) YBCO Films, to create of SQUIDs (Superconducting Quantum Interference Device) on the bases of these films with maximal sensitivity. With the experimental investigation of the stressed films grown by laser ablation method and its properties, the fabrication of the dc-SQUIDs with maximal sensitivity on the bases of the stressed YBCO films were carried out. The stressed film having the value of the critical current density J$_{c}$=3ㆍ$10^{5}$A/$\textrm{cm}^2$ was the more stable than others.ers.s.

• BMB Reports
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• v.30 no.1
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• pp.55-59
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• 1997

The heat shock response is a universal stress response observed in all organisms and cultured cells. The response is regulated at both the transcriptional and translational level. Heat shocked Drosophila melanogaster Kc cells are used as the system for the study of translational regulation. In this system non-heat shock messages are associated with polysome but are not translated in a heat shocked condition. To figure out the change in the translation machinery. the effects of translation elongation inhibitors were tested on Kc cells. The result showed that the sensitivity of translation to these drugs changed in heat shocked cells. The significant changes were the decreased inhibition of heat shock protein synthesis by cycloheximide, emetine. and puromycin. and the increased inhibition of heat shock protein synthesis by verrucarin A. implying that the translation elongation mechanism in heat shocked cells changed.