• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.231-234
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• 2005

The high temperature deformation behavior of AZ 31 Mg alloy was investigated by designing a back propagation neural network that uses a gradient descent-learning algorithm. A neural network modeling is an intelligent technique that can solve non-linear and complex problems by learning from the samples. Therefore, some experimental data have been firstly obtained from continuous compression tests performed on a thermo-mechanical simulator over a range of temperatures $(250-500^{\circ}C)$ with strain rates of $0.0001-100s^{-1}$ and true strains of 0.1 to 0.6. The inputs for neural network model are strain, strain rate, and temperature and the output is flow stress. It was found that the trained model could well predict the flow stress for some experimental data that have not been used in the training. Workability of a material can be evaluated by means of power dissipation map with respect to strain, strain rate and temperature. Power dissipation map was constructed using the flow stress predicted from the neural network model at finer Intervals of strain, strain rates and subsequently processing maps were developed for hot working processes for AZ 31 Mg alloy. The safe domains of hot working of AZ 31 Mg alloy were identified and validated through microstructural investigations.

• Journal of the Korean Home Economics Association
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• v.39 no.11
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• pp.175-192
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• 2001

This study investigated the relationships between inter-cultural experience and socio-psychological adjustment to the current life among children who have refilmed from living abroad. The subject of research consisted of 102 boys and 110 girls from fourth grade through sixth grade who returned to their home country after living in a foreign correlation Data were collected from 5 elementary schools in Seoul. Descriptive statistics, t-tests, correlation analysis and regression were used for data analysis. The results of children's social-psychological adjustment were represented by 3 categories: school/friend relationship, stress/strain and language/learning. The following are the summarized results; First, girl students were more likely to adapt to school/friend relationships in Korea and had lower stress/strain than boys. Second, the children having shorter period of residence in foreign county, lower adaptation ability to different culture and extrovert personality showed higher socio-psychological adjustments after returning to Korea. Third, the adjustment to school/friends was influenced by period of residency in the foreign county, the experience of different culture, and extrovert personality. The experience of different culture and extrovert personality effected stress/strain, and the adjustments to language/learning were influenced only by the ewperiecne of different culture. Lastly, the experience of different culture was the most important variable influencing all 3 categories of socio-psychological adjustments.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.535-536
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• 2021

현대의 스트레스 케어는 대부분 비디오 시청, 상담, 취미 활동 등을 통해 진행된다. 시각, 청각을 스트레스 케어에 활용한 사례는 이미 일상에서 쉽게 접할 수 있음으로 다른 새로운 감각을 요구하고 있다. 본 논문에서는 스트레스 케어를 목적으로, 생체정보를 대상으로 딥러닝 기술 기반의 '사용자 스트레스 및 효과적인 스트레스 해소 요소 판단 알고리즘 모델'을 사용하는 서비스 제공 시스템을 설계한다. 생체정보는 손목시계형 웨어러블을 통해 수집된 심박수, 혈압, 체온, 산소포화도, ECG 등 생체데이터를 사용한다. 제시하는 방법은 실시간으로 수집된 생체정보를 알고리즘, 모델을 통해 스트레스 수치를 예측하여 사용자에게 적절한 음악과 조명을 이용한 시청각적 요소와 아로마 요법을 이용한 후각적 요소를 제공한다.

• Journal of the Korea Society of Computer and Information
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• v.24 no.4
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• pp.145-151
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• 2019

The purpose of this study was to find out whether there was a meaningful change in the learning perception and interpersonal relations of nursing students after completing clinical practice. Participants were 32 nursing students in the third grade. The research data were collected by questionnaire consisting of interpersonal relations and learning perception. The analysis of data was analyzed by SPSS 21 Version. General characteristics were analyzed by descriptive statistics, correlation between variables was analyzed by Pearson's relation, and differences of variables before and after clinical practice were analyzed by paired t-test. The results of the study are as follows. In clinical practice, interpersonal abilities showed a significant correlation with learning outcomes (R =.351, p =.049). The interpersonal abilities of nursing students improved significantly(t =2.264, p =.13) after completion of clinical practice. Nursing college students recognized that their interpersonal abilities had improved after completion of clinical practice, and the improvement of interpersonal abilities was statistically supported. Considering that the interpersonal relationship was an important factor in the clinical practice related stress of the nursing college students, it was meaningful that the interpersonal ability improved after the clinical practice. The positive correlation between interpersonal abilities and learning perceptions in clinical practice of nursing college students suggests future directions for future research. The results of this study will provide basic data on education that will enhance the satisfaction of students' clinical practice and improve their learning outcomes.

• Journal of dental hygiene science
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• v.23 no.4
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• pp.271-281
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• 2023

Background: This study aims to improve dental hygiene education by investigating the relationship between metacognition, learning flow, and problem-solving abilities in dental hygiene majors. Methods: A survey was conducted on 2nd to 4th-year students from dental hygiene programs, with 132 responses analyzed. Data analysis involved t-tests and ANOVA to examine the differences in metacognition, learning flow, and problem-solving abilities based on the general characteristics. Multiple regression analysis was employed to investigate the factors influencing the dependent variable, which is problem-solving abilities. The collected data were analyzed using SPSS. Results: First, when comparing metacognition, learning flow, and problem-solving abilities based on the general characteristics of the study participants, statistically significant differences were observed in common factors such as major satisfaction, subjective academic performance, GPA (grade point average), and reason for major choice (p<0.05). Second, it was found that there is a significant positive correlation between metacognition, learning flow, and problem-solving abilities in dental hygiene students (r≥0.79, p<0.05). In other words, higher levels of metacognition and learning flow were associated with better problem-solving abilities. Third, factors influencing problem-solving abilities were identified, with both metacognition and learning flow having a statistically significant positive impact. It was also noted that metacognition had a greater influence on problem-solving abilities compared to learning flow (adjusted R²=0.815, p<0.05). Conclusion: To enhance the core competency of problem-solving abilities, it is essential to improve metacognition and learning flow. To enhance metacognition and promote learning flow, strategies such as goal setting, utilizing effective learning methods, boosting self-efficacy, managing the learning environment, choosing activities that foster immersion, stress management, self-assessment and feedback integration, improving focus, and utilization a variety of learning experiences will be necessary.

• Korean Journal of Biological Psychiatry
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• v.4 no.2
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• pp.237-245
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• 1997

The study was designed to evaluate the significant roles of SSRI in rat of depression model. Chronic exposure to mild unpredictable stress has been found to depress the consumption of sweet 1% sucrose solutions in the Sprague-Dawley rats. We applied the variety of 11 types of stress regimens and identified depressive behaviours(developed by Willner) in 70 Sprague-Dawley rats. Rats in experiments were stratified into 6 groups, ie ; 3 kinds of SSRI(paroxetine, fluoxetine, sertraline), clomipramine, choline and saline control. Memory function was evaluated by passive avoidance learning and retention test. The authors determined how long memory retention would remain improved with 24 hour, 1 week, 2 weeks, 3 weeks, and 4 weeks at training-testing interval in depressive states of the Sprague-Dawley rats. The results were as follows ; 1) There were no significant differences between the 6 groups at the 24 hour training-testing interval. 2) The paroxetine treated group showed significant differences from the control group at the 1 week and 2 weeks training-testing interval. 3) The paroxetine and the fluoxetine treated groups showed singificant differences from the control group at 3 week training-testing interval. 4) The paroxetine and the choline treated groups showed significant differences from the control group at 4 week training-testing interval. In summary, paroxetine had an effect on long term memory processing from 1st week to 4th week. Also, fluoxetine(at 3rd week) and choline(at 4th week) had effect on long term memory processing. Sertraline, clomipramine were ineffective on memory processing during 4 weeks observation. Possible explanations why paroxetine had early effect on memory processing than the other selective serotonin reuptake inhibitors are rapid bioavailability, which is the characteristics of pharmacokinetics of paroxetine. In clinical situation, author carefully suggest that SSRI would be beneficial to improve the memory function caused by depressive neurochemical changes.

• Journal of Society of Preventive Korean Medicine
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• v.14 no.3
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• pp.51-61
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• 2010

This study aimed to evaluate musculoskeletal workload associated with the work of hair designers, to identify the factors associated with work-related stress, depression and musculoskeletal symptoms in Hair Designers, and to check the painful areas based on patients who complained of musculoskeletal symptoms. The data were collected from 279 hair designers in Daegu metropolitan city from February 1 to August 31 of 2009. A summary of the results was as follows : According to work-related stress in study subjects, the degree of stress load was relatively higher in association with the working demand, the relational conflicts and the organizational culture, but the degree of stress was found to be relatively lower in association with the physical environment, work-related autonomy, an insufficient compensation and an occupational instability. People engaged for beauty business have gotten lots of stress because of the endless needs from customers, the pressure of the learning new skills and the uncomfortable working environment. These are able to cause the musculoskeletal disorder. Under this circumstance, small fries do not have any prevention managements for improving the musculoskeletal diseases and they are not afforded to have regular checkup. When teaching the people related with beauty business, it is necessary to provide accurate information like correct carriage to reduce musculoskeletal disorder stress.

• KNOM Review
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• v.24 no.2
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• pp.35-47
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• 2021

Various stress exists in a modern society, which requires constant competition and improvement. A person under stress often shows his pressure in his facial expression and language. Therefore, it is possible to measure the pressure using facial expression and language analysis. The paper proposes a stress measurement system using facial expression and language sensitivity analysis. The method analyzes the person's facial expression and language sensibility to derive the stress index based on the main emotional value and derives the integrated stress index based on the consistency of facial expression and language. The quantification and generalization of stress measurement enables many researchers to evaluate the stress index objectively in general.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1347-1356
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• 2024

Measuring the residual stress in the components in nuclear power plants is crucial to their safety evaluation. The instrumented indentation technique is a minimally invasive approach that can be conveniently used to determine the residual stress in structural materials in service. Because the indentation behavior of a structure with residual stresses is closely related to the elastic-plastic behavior of the indented material, an accurate understanding of the elastic-plastic behavior of the material is essential for evaluation of the residual stresses in the structures. However, due to the analytical problems associated with solving the elastic-plastic behavior, empirical equations with limited applicability have been used. In the present study, the impact of the non-equibiaxial residual stress state on indentation behavior was investigated using finite element analysis. In addition, a new nonequibiaxial residual-stress prediction methodology is proposed using a convolutional neural network, and the performance was validated. A more accurate residual-stress measurement will be possible by applying the proposed residual-stress prediction methodology in the future.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.391-395
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• 2023

Helicopter accidents due to spatial disorientation in low visibility conditions continue to persist as a major issue. These incidents often stem from human error, typically induced by stress, and frequently result in fatal outcomes. This study employs machine learning to analyze flight data and evaluate the efficacy of a flight illusion detection algorithm, laying groundwork for further research. This study collected flight data from approximately 20 pilots using a simulated flight training device to construct a range of flight scenarios. These scenarios included three stages of flight: ascending, level, and descent, and were further categorized into good visibility conditions and 0-mile visibility conditions. The aim was to investigate the occurrence of flight illusions under these conditions. From the extracted data, we obtained a total of 54,000 time-series data points, sampled five times per second. These were then analyzed using a machine learning approach.