• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.8
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• pp.671-678
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• 2018

Helicopter noise prediction is an essential process for developing low noise helicopter technology. In this paper, the noise prediction method is developed using the helicopter integrated performance analysis program CAMRAD-II and in-house noise analysis code. In addition, the analytical technique was verified by analyzing blade-vortex interaction noise, which is the biggest cause of helicopter noise. In order to predict the actual helicopter noise, the noise analysis was performed for the flyover and approach condition, which is the standard measurement condition of the International Civil Aviation Organization (ICAO). Finally, we confirmed the suitability of the analytical method through comparison and analysis with the flight test results.

• Journal of Engineering Education Research
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• v.16 no.2
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• pp.69-77
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• 2013

A study was conducted to find that which educational factors affect the psychological characteristics related to one's major of female students in engineering. The study was conducted through reviewing the advanced literatures and data for surveys was collected from the 216 female students at the college of engineering. This data was analyzed using descriptive statistics, the ANOVA test, hierarchical regression analysis, and factors analyzed by SPSS window's 12.0. The results are as follows. The major aspirations of female students at the college of engineering are affected by the grades (GPA) they have achieved in the past and by the professors' support they have received from the educational environment, by the WIE program participation. However, this survey showed that the support of professors was the most influential factor. The self-efficacy about employment is affected by the grades (GPA) they have achieved and the professors' support they have received. Therefore, the finding shows that the professors' support in their major field is the most affective factor to both characteristics such as the self-efficacy, the major aspirations.

• Composites Research
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• v.33 no.3
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• pp.133-139
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• 2020

In this research, the vibration characteristics of composite quadcopter are analyzed, and avoidance design and analysis are performed to avoid resonance. The full platform of a commercial quadcopter with composite rotor arm is analyzed to see the vibration characteristics using FEM program. The manufactured stacking sequences of rotor arm is used for analysis, and the natural frequencies are compared with experimental results and simple analytic model results. It is also confirmed that the natural frequency of the particular mode is included within the operation range of the motor. The resonance avoidance design is carried out by selecting three variables from the existing model: stacking sequence, rotor-arm pipe length, and pipe thickness.

• Journal of Nutrition and Health
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• v.45 no.6
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• pp.552-561
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• 2012

Metabolic syndrome is a cluster of metabolic risk factors associated with increased risk of cardiovascular diseases. Recently, the prevalence of metabolic syndrome has increased in Korea. The aim of this study was to develop a Healthy Han-sik Nutrition Education Program (HHNEP) based on commonly recognized Korean foods in order to decrease metabolic syndrome risks. The target population of the HHNEP is adults with metabolic risk factors. The initial version of the HHNEP was developed based on a review of literature and various dietary guidelines by expert committees as well as the results of a survey on the perception of common Korean dishes and foods as Han-sik. The focus group discussion conducted of nine participants from the target population. After minor modification, the final version was developed. The contents included five sections: 1) aims, 2) introduction of Korean Food Guidance System, 3) cholesterol contents in food, 4) menu planning method using Han-sik, and 5) examples of daily Han-sik menu. The Han-sik list was selected based on the results from a Han-sik perception answered by 35 Korean adults aged 30-60 years using 517 frequently consumed Korean foods from the fourth Korea National Health and Nutrition Examination Survey. The nutrition education program was developed based on scientific evidence for the prevention of metabolic syndrome and focuses on tailoring education to an individual's dietary problems. Educational method was developed by a group of expert committees based in planned behavior theory and related research results. The education method consisted of assessment of current diet, four face-to-face nutrition education sessions over 8 weeks, and evaluation after 8 and 16 weeks. Initial version of nutrition education materials and methods was tested for feasibility by a select group of nine Korean healthy adults. Successful implementation of the program would include application by nutritional professionals at the health promotion center of the hospitals, public health center, and work sites. Intervention studies are needed to evaluate the feasibility and effectiveness of this program before large-scale applications.

• Journal of Ginseng Research
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• v.47 no.4
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• pp.561-571
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• 2023

Background: Escalating evidence shows that ginseng possesses an antiaging potential with cognitive enhancing activity. As mountain cultivated ginseng (MCG) is cultivated without agricultural chemicals, MCG has emerged as a popular herb medicine. However, little is known about the MCG-mediated pharmacological mechanism on brain aging. Methods: As we demonstrated that glutathione peroxidase (GPx) is important for enhancing memory function in the animal model of aging, we investigated the role of MCG as a GPx inducer using GPx-1 (a major type of GPx) knockout (KO) mice. We assessed whether MCG modulates redox and cholinergic parameters, and memory function in aged GPx-1 knockout KOmice. Results: Redox burden of aged GPx-1 KO mice was more evident than that of aged wild-type (WT) mice. Alteration of Nrf2 DNA binding activity appeared to be more evident than that of NFκB DNA binding activity in aged GPx-1 KO mice. Alteration in choline acetyltransferase (ChAT) activity was more evident than that in acetylcholine esterase activity. MCG significantly attenuated reductions in Nrf2 system and ChAT level. MCG significantly enhanced the co-localization of Nrf2-immunoreactivity and ChAT-immunoreactivity in the same cell population. Nrf2 inhibitor brusatol significantly counteracted MCG-mediated up-regulation in ChAT level and ChAT inhibition (by k252a) significantly reduced ERK phosphorylation by MCG, suggesting that MCG might require signal cascade of Nrf2/ChAT/ERK to enhance cognition. Conclusion: GPx-1 depletion might be a prerequisite for cognitive impairment in aged animals. MCG-mediated cognition enhancement might be associated with the activations of Nrf2, ChAT, and ERK signaling cascade.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.4
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• pp.116-122
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• 2013

This study develops a dynamic scheduling model for parallel machine scheduling problem based on genetic algorithm (GA). GA combined with discrete event simulation to minimize the makespan and verifies the effectiveness of the developed model. This research consists of two stages. In the first stage, work sequence will be generated using GA, and the second stage developed work schedule applied to a real work area to verify that it could be executed in real work environment and remove the overlapping work, which causes bottleneck and long lead time. If not, go back to the first stage and develop another schedule until satisfied. Small size problem was experimented and suggested a reasonable schedule within limited resources. As a result of this research, work efficiency is increased, cycle time is decreased, and due date is satisfied within existed resources.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.11
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• pp.855-864
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• 2013

Active tab is one of the promising technology for the BVI (blade-vortex interaction) noise reduction, and analysis of noise reduction performance is very important phase of the technology development. For the purpose of analysing the performance of noise reduction using active tab, CAMRAD II model for a model-scale rotor system was constructed utilizing structural design result and airfoil aerodynamic data generated by CFD (computational fluid dynamics) calculation. HHC strategy was applied to descent flight condition and air-load was calculated by CAMRAD II then variations of BVI noise was calculated by in-house program. Calculation result with respect to tab length and control phase changes showed BVI noise could be reduced by -3.3dB.

• Journal of the Korea Convergence Society
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• v.8 no.8
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• pp.307-314
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• 2017

The Purpose of this study was to identify the level of learned helplessness and the relationship among variables affecting their learned helplessness. We have carried out research on 799 students. and collected data were analyzed using t-test, ANOVA, scheffe test, pearson's correlation coefficient. As a result, the mean score of learned helplessness was 2.55 (${\pm}.61$), Of the sub-domains, 'lack of control' was the highest with 2.85 (${\pm}.44$). And It was found that the helplessness was high in the case of poor fellowship, low academic achievement and poor family cooperation. These results were significantly correlated. Through the follow-up research, it is necessary to carry out management to reduce the learned helplessness by developing differentiated program that can reduce the learned helplessness of university students by identifying variables that can explain the learned helplessness of university students.

• Toxicological Research
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• v.22 no.3
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• pp.275-282
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• 2006

In previous our studies, we have reported that eugenol derived from Eugenia caryophyllata(Myrtaceace) exhibits acute N-methyl-D-aspartate(NMDA)- and oxygen/glucose deprivation-induced neurotoxicity in primary cortical cultures and protects hippocampal neurons from global ischemia. In this study, we investigated whether the extracts and fractions of E. caryophyllata or eugenol shows the neuroprotective effects against delayed neuronal injury evoked by NMDA or ${\alpha}$-amino-3-hydroxy-5-methylisoxazole propionate(AMPA), and oxidative damage induced by arachidonic acid-, hydrogen peroxide-, $FeCl_2$/ascorbic acid-, and buthionine sulfoximine(BSO) in primary cortical cultures. We examined the neurotoxicity of eugenol itself in cultures and inhibitory effect of eugenol on NMDA- or kainate(KA)-induced convulsion in BALB/c mice. Each water, methanol extract and methanol fraction of E. caryophyllata was significantly attenuated NMDA-induced delayed neurotoxicity, respectively. Eugenol exhibited a significant inhibitory action against the convulsion evoked by NMDA and KA, and reduced delayed or brief neurotoxicity induced by NMDA, AMPA, and various oxidative injuries. These results suggest that eugenol derived from E. caryophyllata may contribute the neuroprotection against delayed-type excitotoxicity and excitotoxins-mediated convulsion through the amelioration of oxidative stress.

• The Journal of the Korea Contents Association
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• v.14 no.8
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• pp.297-306
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• 2014

This paper is a descriptive study that aims to investigate attitudes towards menstruation, symptoms and coping behaviors in order to develop a program for building positive attitudes toward menstruation in primary school students. The mean age of menarche was 12.3 years, and students generally showed negative attitudes towards menstruation. Students who experienced menarche had relatively more positive attitudes than those who did not. However, no significant difference was exhibited. Menstrual symptoms occurred rarely or at a moderate level by showing a low score of 2.12 points. Of all sub-factors, 'pain' was the most serious. The most common coping behaviors during menstruation was 'I take a warm shower' and 'I take a rest or nap', while respondents rarely checked 'I take vitamin B supplements' and 'I take painkiller'. Based on the above findings, the study intends to perform a systematic study to further identify the factors affecting menstrual attitudes in primary school students. In addition, this paper suggests effective healthcare education on menstruation to build positive attitudes towards menstruation and education and counseling programs for adopting appropriate coping strategies to deal with menstrual symptoms.