• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.869-870
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• 2006

일반적으로 초전도선재를 이용한 코일의 전자기력에 의한 스트레스 계산에 있어서는 코일의 전류밀도분포와 자속밀도분포의 선형적인 관계를 이용하나 아직까지 초전도체 특유의 비선형적인 특성을 이용한 스트레스의 계산은 미비하다. 본 논문에서는 13턴의 소형 싱글팬케이크 코일을 초전도의 특성을 적용해 해석하고 인가전류가 $0.3I_c,\;0.5I_c,\;0.8I_c$ 인 경우에 대해서 전자기력에 의한 코일의 스트레스를 유한요소법으로 계산하였다. 계산 결과 코일의 radial stress와 hoop stress는 모두 코일의 자속밀도분포와 유사한 모습을 나타내었다.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.2
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• pp.70-77
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• 2022

This study is a study to analyze the stress difference of pilots according to the category of aircraft. According to previous studies, pilot stress is affected by several factors such as flight time, fatigue regulation, and operating environment, and it is known that stress also affects cardiac variability. In this paper, we analyzed that there is a difference in stress according to the operating environment through airline pilots and pilots of educational institutions, and then tested the difference in stress between airplane pilots and helicopter pilots. This study differs in that it is a study that has almost no empirical research on pilot fatigue and stress considering the role of flight crew members and operational conditions for each mission. If we expand and verify the sample of the results for the stress difference in the future, it will be a great contribution to practical aviation safety research in connection with the fatigue risk management system in the future.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.10 no.6
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• pp.54-61
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• 1996

In this paper, the conventional ZVS-QRC buck dc-dc converter is analyzed using simulation and the problem in confirmed through it. According to varying the load resistance lower, it is provided that the stress of the device is increased. The reason is seen that the voltage is increased by parasitic capacitance of freewheeling diode. Novel ZVS-converter is proposed to improve the problems.

• Journal of Life Science
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• v.19 no.4
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• pp.429-435
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• 2009

Oxidative stress is a consequence of an imbalance of the defense system against cellular damage generated by reactive oxygen species (ROSs) such as superoxide anions (menadione; MD). Most organisms have evolved a variety of defense systems to protect cells from adverse conditions. In order to evaluate stress tolerance against oxidative stress generating MD, comparative analyses of antioxidant capacity, or free radical scavenger ability, were performed between S. cerevisiae KNU5377 (KNU5377) and three wild-type S. cerevisiae strains. In a medium containing 0.4 mM MD, the KNU5377 strain showed higher cell viability and antioxidant ability, and contained higher levels of trehalose, superoxide dismutase, thioredoxin system, glucose-6-phosphate dehydrogenase, and some heat shock proteins. The KNU5377 strain also produced a lower level of oxidative stress biomarker than the other three yeast strains. These results indicate that S. cerevisiae KNU5377 has a higher level of tolerance to oxidative stress due to the increased expression of cell rescue proteins and molecules, thus alleviating cellular damage more efficiently than other S. cerevisiae strains.

• The Journal of the Korea Contents Association
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• v.19 no.11
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• pp.122-131
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• 2019

This study analyzed the moderating effect according to school levels in the structural relationship between stressful interpersonal relationships at work and rumination in teachers' depression. For this study, a research model was formed based on theoretical understandings and a literature review. The researchers surveyed 811 teachers at primary and secondary schools to measure scales of depression, rumination, and stress in interpersonal relationships at work. Primary education and secondary education were the grouping variables for the school levels, and the collected data was analyzed using multi-group structural equation modeling. Also, to affirm equivalence between the two models, the data was investigated using the constrained model of measurement equivalence. The research results verified the equivalence between the two models and the moderating effect by comparing the path coefficients of the two models on the assumption of equivalence constraint. As a result, the moderating effect according to school levels was revealed on the path from stressful interpersonal relationships at work to depression. Grounded on this analysis, stress in interpersonal relationships at work mediates the impact of rumination in teachers' depression. In addition, the research revealed that the moderating effects on stressful interpersonal relationships at work varied according to school level, and the moderating effect of stress in interpersonal relationships at work affected middle school teachers but not primary school teachers.

• Journal of dental hygiene science
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• v.13 no.4
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• pp.440-448
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• 2013

The purpose of this study was to analyze the effects of perceived stress on dietary habits and oral health behaviors in Korean adolescents. Data were from the Korea Youth Risk Behavior Web-based Survey (KYRBS) in 2011. A total of 74,186 adolescents were surveyed using the self-administered questionnaire. Logistic regression analyses were performed to elucidate the effects of perceived stress on dietary habits and oral health behaviors. Statistical analyses were conducted, and p<0.05 were considered significant. We found that adolescents with higher stress were more likely to increase the risk of adverse dietary habits (low consumption of fruits, vegetables and milk, high consumption of carbonated soft drinks, fast food and cookie) compared to those with lower stress. Regarding the relationship between perceived stress and oral health behaviors, adolescents with higher stress were less likely to practice oral health behaviors such as brushing teeth after snack consumption and brushing teeth before sleep compared to those with lower stress. This result indicates that adolescents' perceived stress might play a significant role in the negative dietary habits and oral health behavior.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.459-471
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• 2024

In modern society, where tension and stress are ubiquitous, individuals often experience psychological imbalances. These stressors not only affect mental well-being but also manifest physically, through the skin. Consequently, a new term psychodermatology combining psychiatry and dermatology, has emerged, garnerning attention and research focus. In this study, we aimed to develop materials improving chronic skin conditions caused by stress by utilizing a compound of Cucurbita moschata, Paeonia japonica, and Prunus cerasus known to alleviate skin disorders. We sought to develop and validate the efficacy of materials alleviating chronic skin conditions induced by stress in keratinocytes..Therefore, in this study we analyzed the effects of a complex extract using Cucurbita moschata, Paeonia japonica, and Prunus cerasus on HaCaT keratinocyte cells to understand how it influences them. The complex extract on HaCaT keratinocyte cells showed a concentration-dependent decrease in the expression levels of TNF-α, IL-1β, IL-6, MDC, and TARC at concentrations of 12.5, 25, 50 and 100 ㎍/mL. Particularly noteworthy was the efficacy observed in inhibiting IL-1β, with a reduction of over 40% at a concentration of 100 ㎍/mL. Additionally, the production levels of AQP-3, HA, and filaggrin exhibited a significant concentration-dependent increase. The protein expression of p-ERK, p-JNK, and p-p38, which were elevated by TNF-α/IFN-γ, was significantly decreased with the treatment of the complex extract. These findings suggest that the compound extract may be utilized as a material for treating and preventing skin conditions, potentially mitigating the adverse effects of the mutual relationship between skin disorders and stress.

• Korean Journal of School Psychology
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• v.18 no.3
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• pp.371-398
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• 2021

Student-athletes identify themselves as athletes first and students second and experience identity foreclosure in which they rarely consider other possibilities for their career besides professional athletes. There is a gap between the career education that college student-athletes and regular students get, so we conducted this study to test the effectiveness of a career education program. The proposed career education program was based on Super and Ginsberg's career development theory and Holland's career choice theory. Data were collected from 13 college student-athletes using a pretest-posttest research design and analyzed using a t-test. The program was conducted in the form of 90-minute weekly sessions over 3 weeks. The program's effectiveness was measured in terms of participants' stress from a lack of career information, career preparedness, self-understanding, and career decision-making self-efficacy. The results showed that each variable, except stress from a lack of career information, was significantly improved after the program compared to before the program, indicating that the program was effective. Theoretical and practical implications regarding career education for student-athletes are discussed in this paper.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.217-223
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• 2016

The purpose of this study is to investigate the predictability of variables among technology easy to use, perceived usefulness, and technostress that had impacts on kindergarten preservice teachers' technology intention to use. For this study, the survey data collected by 64 students who were enrolled in the kindergarten preservice teacher education were analysed by using multiple regression analysis. The results of this study showed as follows. First, technology easy to use significantly affected perceived usefulness. Second, technology easy to use negatively affected technostress. Third, perceived usefulness significantly affected technology intention to use while technostress negatively affected it. From this results, it is revealed that various technology training opportunities would be provided for improving preservice teachers' technology intention to use and lessing preservice teachers' technostress. Furthermore, effective teaching-learning strategies for utilizing technology as an educational media should be developed in the early childhood educational environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2990-2996
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• 2009

S. mutans, one of a major causal agents of dental caries, is component of the dental plaque and produces various organic acids such as lactic acid as the end-product of glycolysis. In this study, we are interested in comparing the gene expression of acid-shocked and control cells of S. mutans isolated from Korean with caries. Expression levels of gtfB, gtfC, gtfD and ftf were analyzed by Real-time PCR, when the cells were grown under 20 mM lactic acid stress in the exponential phase. The data showed reduced expression of these genes. S. mutans is known to have developed a variety of mechanisms to tolerate acid sterss. A more detailed analysis of the functions and interactions of acid stress proteins connecting the growth, stress tolerance, biofilm formation is under way.