• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.75-81
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• 2000

The anisotropy of soils has an important effect on stress-strain behavior. In this study, an attempt has been made to implement artificial neural network model for modeling the stress-strain relationship and predicting the undrained shear strength of normally consolidated clay with varying consolidation pressure ratios. The multi-layer neural network model, adopted in this study, utilizes the error back-propagation loaming algorithm. The artificial neural networks use the results of undrained triaxial test with various consolidation pressure ratios and different effective vertical consolidation pressure fur learning and testing data. After learning from a set of actual laboratory testing data, the neural network model predictions of the undrained shear strength of the normally consolidated clay are found to agree well with actual measurements. The predicted values by the artificial neural network model have a determination coefficient$(r^2)$ above 0.973 compared with the measured data. Therefore, this results show a positive potential for the applications of well-trained neural network model in predicting the undrained shear strength of cohesive soils.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.7
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• pp.23-31
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• 2008

Experiment results are presented for gate oxide degradation under the constant voltage stress conditions using MOSFETs with 3-nm-thick gate oxides that are treated by deuterium gas. Two kinds of methods, annealing and implantation, are suggested for the effective deuterium incorporation. Annealing process was rather difficult to control the concentration of deuterium. Because the excess deuterium in gate oxide could be a precursor for the wear-out of gate oxide film, we found annealing process did not show improved characteristics in device reliability, compared to conventional process. However, deuterium implantation at the back-end process was effective method for the deuterated gate oxide. Device parameter variations as well as the gate leakage current depend on the deuterium concentration and are improved by low-energy deuterium implantation, compared to those of conventional process. Especially, we found that PMOSFET experienced the high voltage stress shows a giant isotope effect. This is likely because the reaction between "hot" hole and deuterium is involved in the generation of oxide trap.

• The Journal of the Korea Contents Association
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• v.20 no.2
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• pp.636-648
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• 2020

The purpose of this preliminary study is to help put the women with career breaks in Science and Technique back to work and keep on working. For this purpose, we developed a 8-session group counseling for woman scientists and technicians with career break: Self-Growth group and Interpersonal Conflict Resolution Group. A total of 14 people participated in Group counseling. The most of participants reported that they have experienced lowered self-esteem, difficulties in relationship with family and colleagues, and psychological pressure and distress. The participants in the Interpersonal Conflict Resolution Group Counseling showed positive changes at stress coping strategies. From this study, the women with career breaks in Science and Technique will be expected to overcome the difficulties of career breaks wisely, demonstrate and confirm their competence, and restore from stress and psychological burnout. Based on the results of this study, implications and limitations of this study and future research were discussed.

• Journal of Acupuncture Research
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• v.25 no.6
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• pp.35-46
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• 2008

Objectives : Chronic pain affects and is affected by physical and psychosocial factors. It also has a complicated and indefinite mechanism. This research is for clarifying relations with chronic pain, stress, and autonomic nerve system by comparing HRV and Stress Reaction Index(SRI) of chronic pain patients with those of acute pain patients. Methods : The subjects were 32 patients who visited Kangnam Kyunghee Hospital for nuchal pain or low back pain treatment from March 2008 to September 2008. Among them, 16 patients who suffered over 6 months are classified chronic pain group and 16 patients who suffered under 6 months as acute pain group. All subjects had their HRV(SA-2000E: Medicore Co..Ltd. Korea) and SRI measured at first visit. We studied the difference of HRV between two groups.(Statistics by Student t-test, p<0.05) Results : R-MSSD, TP, VLF, LF, HF and LF/HF ratio of the chronic pain group were significantly lower than those of the acute pain group. Compared with those of the acute pain group, total SRI of the chronic pain group were low but it's not significant except frustration. Conclusion : The results of HRV of the chronic pain group patients show that chronic pain is related to psychosocial factor and autonomic disturbance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.10
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• pp.1239-1249
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• 2013

In this study we establish a process to predict hardening behavior considering the Bauschinger effect for zircaloy-4 sheets. When a metal is compressed after tension in forming, the yield strength decreases. For this reason, the Bauschinger effect should be considered in FE simulations of spring-back. We suggested a suitable specimen size and a method for determining the optimum tightening torque for simple shear tests. Shear stress-strain curves are obtained for five materials. We developed a method to convert the shear load-displacement curve to the effective stress-strain curve with FEA. We simulated the simple shear forward/reverse test using the combined isotropic/kinematic hardening model. We also investigated the change of the load-displacement curve by varying the hardening coefficients. We determined the hardening coefficients so that they follow the hardening behavior of zircaloy-4 in experiments.

• Molecules and Cells
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• v.37 no.9
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• pp.672-684
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• 2014

The exact causes of cell death in Parkinson's disease (PD) remain unknown despite extensive studies on PD.The identification of signaling and metabolic pathways involved in PD might provide insight into the molecular mechanisms underlying PD. The neurotoxin 1-methyl-4-phenylpyridinium ($MPP^+$) induces cellular changes characteristic of PD, and $MPP^+$-based models have been extensively used for PD studies. In this study, pathways that were significantly perturbed in $MPP^+$-treated human neuroblastoma SH-EP cells were identified from genome-wide gene expression data for five time points (1.5, 3, 9, 12, and 24 h) after treatment. The mitogen-activated protein kinase (MAPK) signaling pathway and endoplasmic reticulum (ER) protein processing pathway showed significant perturbation at all time points. Perturbation of each of these pathways resulted in the common outcome of upregulation of DNA-damage-inducible transcript 3 (DDIT3). Genes involved in ER protein processing pathway included ubiquitin ligase complex genes and ER-associated degradation (ERAD)-related genes. Additionally, overexpression of DDIT3 might induce oxidative stress via glutathione depletion as a result of overexpression of CHAC1. This study suggests that upregulation of DDIT3 caused by perturbation of the MAPK signaling pathway and ER protein processing pathway might play a key role in $MPP^+$-induced neuronal cell death. Moreover, the toxicity signal of $MPP^+$ resulting from mitochondrial dysfunction through inhibition of complex I of the electron transport chain might feed back to the mitochondria via ER stress. This positive feedback could contribute to amplification of the death signal induced by $MPP^+$.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.3
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• pp.315-323
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• 2010

Five concrete compressive stress-strain models have been analyzed to check the validity of the strength method for determining the nominal moment of strengthened members using commercially available computer language. The results show that the concrete stress-strain models do not influence on the flexural analysis. The moment of a strengthened member obtained from the flexural analysis at concrete compressive strain reaching 0.003 is well agreed with nominal moment using the strength method. The flexural analysis results show that when the steel reinforcement, FRP ratio, FRP failure strain, and concrete failure compressive strain are relatively lower, the strength method overestimates the flexural capacity of the strengthened members.

• Journal of the Ergonomics Society of Korea
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• v.32 no.6
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• pp.495-501
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• 2013

Objective: The purpose of this study was to survey of the subjective health status of the elderly farmer. Background: With increase of aged population, the health of the elderly farmer has become main concerns of the elderly in the rural community. For the effects of the factors related to quality of life, subjective health condition showed the largest influence. Method: The survey was conducted by 326 elderly farmers aged 50 and older in rural areas through structured questionnaires. Survey questionnaire consisted items of general characteristics, health-related life habits, levels of stress(SF-PWI), symptom of musculoskeletal diseases and general level of health(SF-36). For the data analysis, SPSS 19.0K was used, and analysis was conducted by using frequency, percentage, mean, and standard deviation. For the symptom prevalence of musculoskeletal disorders and comparison of average level of health, chi-square test and t-test were used. Results: The results of the study are as follows. It was shown that the symptom prevalence of musculoskeletal disorders had a significant difference in gender (p<0.01). Frequency analysis on presence of musculoskeletal symptoms in each part of body showed that leg/knee region was 28.1%, back region was 26.6%, shoulder region was 18.0%, arm/elbow region was 11.9%, hand/wrist region was 8.2% and neck region was 7.2%. According to comparison of average level of health, a social functioning were the highest as score 87.3, followed by mental health(65.6) and role limitation-emotional(65.5). Conclusion: Health promotion program for the elderly and female in the rural are needed. Application: The survey of the subjective health status of the elderly should be used for planning factors to make a health improvement plan in elderly farmer.

• The Research Journal of the Costume Culture
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• v.22 no.6
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• pp.911-929
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• 2014

This study is designed to analyze the similarity of fit and appearance between 3D virtual torso length sloper with real torso length sloper according to three 3D virtual clothing simulation programs (Optitex, CLO 3D, i-Designer), three body types (A, N, H) and fit status. We selected three representative body type models of females aged 20~30 and got their direct body measurements. Using these body measurements, we developed three 3D avatar body models and made three torso length fitted sloper with long sleeves. Thirty expert fit judges consisting of technical designers and graduate students assessed the similarity of fit and appearance between 3D virtual clothing and real clothing by observing images classified into front, back and side scene. We conducted ANOVA and post-hoc analyses to compare fit and appearance between real clothing and virtual clothing depending on three program. The results showed that CLO 3D represented fit and silhouette most similarly among the programs, especially girths, width and length. i-Designer tended to be relatively good to represent stress fold amount and silhouette. Optitex was assessed relatively better in expressing ease amounts in torso girths and armscye girths, but relatively worse for width, length, stress fold amount and silhouette.

• Journal of the Korean Society of Safety
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• v.28 no.3
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• pp.69-73
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• 2013

The purpose of this paper is to analyze the carbonization pattern and operation characteristics of an MCCB. The MCCB is consisted of the actuator lever, actuator mechanism, bimetallic strip, contacts, up and down operator, arc divider or extinguisher, metal operation pin, terminal part, etc. When the actuator lever of the MCCB is at the top or the internal metal operation pin is in contact with the front part, the MCCB is turned on or off. It means trip state if the actuator lever or the internal metal operation pin moves to back side. In the UL 94 vertical combustion test, white smoke occurred from the MCCB when an average of 17~24 seconds elapsed after the MCCB was ignited and black smoke occurred when an average of 45~50 seconds elapsed. It took 5~6 minutes for the MCCB surface to be half burnt and took an average of 8~9 minutes for the MCCB surface to be entirely burnt. In the UL 94 test, the MCCB trip device operated when an average 7~8 minutes elapsed. If the MCCB trip has occurred, it may have been caused by an electrical problem such as a short-circuit, overcurrent, etc., as well as fire heat. From the entire part combustion test according to KS C 3004, it was found that the metal operation pin could be moved to the MCCB trip position without any electrical problems.