• Composites Research
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• v.32 no.5
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• pp.216-221
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• 2019

Piecewise integrated composite (PIC) beam has different stacking sequences for several regions with respect to their superior load-resisting capabilities. On the interest of current research is to improve bending characteristics of PIC beam, with assigning specific stacking sequence to a specific region with the help of machine learning techniques. 240 elements of from the FE model were chosen to be reference points. Preliminary FE analysis revealed triaxialities at those regularly distributed reference points to obtain learning data creation of machine learning. Triaxiality values catagorise the type of loading i.e. tension, compression or shear. Machine learning model was formulated by learning data as well as hyperparameters and proper load fidelity was suggested by tuned values of hyperparameters, however, comparatively higher nonlinearity intensive region, such as side face of the beam showed poor load fidelity. Therefore, irregular distribution of reference points, i.e., dense reference points were distributed in the severe changes of loading, on the contrary, coarse distribution for rare changes of loading, was prepared for machine learning model. FE model with irregularly distributed reference points showed better load fidelity compared to the results from the model with regular distribution of reference points.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.291-300
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• 2018

This descriptive study was conducted to determine the influence of stress coping styles of nursing students on problem solving ability. Data were collected from 142 nursing students in the M-area from September 20, 2016, to November 30 and analyzed using SPSS WIN 21.0. The average degree of stress coping styles was $3.36{\pm}.30$ (5 point-scale), problem solving abilities was $3.42{\pm}.38$ (5 point-scale). Among the subdomains of stress coping styles, problem focusing was highest, with a score of $3.60{\pm}.42$. Additionally, among the subdomains of problem solving ability, clarification was highest, with a score of $3.50{\pm}.51$. The problem solving abilities of nursing students showed a positive correlation with stress coping styles (r=0.53, p<.001) and was positively correlated with problem focusing (r=0.66, p<.001), positive point of view (r=0.53, p<.001), and social support navigation (r=0.42, p<.001). In addition, the factor with the greatest effect among subdomains of stress coping styles was problem focusing (${\beta}=0.416$, p<.001) and positive point of view (${\beta}=0.257$, p=.002). These two factors were found to explain 54.3% of the variance in problem solving ability. Therefore, the results of this study indicate that application of teaching-learning methods has the potential to improve students' problem-solving ability through problem-oriented and positive stress coping behavior.

• Korean Journal of Childcare and Education
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• v.9 no.6
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• pp.223-241
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• 2013

The purpose of this study was to examine the influence of teacher efficacy and stress coping strategies on job satisfaction of teachers in early childhood education and care. 189 teachers were recruited from 8 day care centers and 10 kindergartens in Seoul, Kyunggi, Kyungbuk, and Chonbuk provinces in Korea. Data were analyzed through frequencies, Pearson's correlations, and the stepwise regression analyses using PASW 18.0. The findings are as follows. First, the result showed that teachers in ECEC were most likely to be satisfied with their job characteristics most among the 4 subcategories in job satisfaction. They also perceived their the ability of discipline high for teacher efficacy, and used the direct coping strategy most as a stress coping strategy. Second, the teachers' ability to create a positive learning atmosphere affected job characteristics, the ability to participate in decision-making affected the relationship with director and colleagues, working environment, welfare and salary the most. Third, the direct coping strategy had the most impacts on all subcategories of job satisfaction. The results of this study may provide basic data for finding effective way to increase job satisfaction of teachers in ECEC.

• Korean Journal of Medicinal Crop Science
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• v.27 no.6
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• pp.365-375
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• 2019

Background: Oxidative stress plays an important role in neuro-degenerative disorders such as Alzheimer's disease. Oxidative stress is mediated by reactive oxygen species (ROS), which are implicated in the pathogenesis of numerous diseases, and account for the toxicity of a wide range of compounds. Methods and Results: In order to study the neuro-protective effect of the complex extracts of Aster scaber Thunberg (AS) and Chaenoleles sinensis Koehne (CSK) against hydrogen peroxide in PC12 cells, cell viability was evaluated by the MTT assay using tetrazole, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and the intracellular ROS levels were determined the by 2',7'-dichlorofluorescein diacetate (DCF-DA) assay. In order to examine the anti-amnesic effects of the complex extracts of AS and CSK, behavioral tests were performed on male ICR mice. The ameliorating effect of the complex extracts against Aβ_1-42-induced learning and memory impairment was analyzed by y-maze and passive avoidance tests. The AS and CSK extracts showed neuro-protective activity both in vitro and in vivo, and the neuro-protective effect of their 60 : 40 (AS : CSK) mixture was better than that of the other mixtures. Moreover, the complex extracts synergistically inhibited acetylcholinesterase activity and rapid peroxidation. Conclusions: A mixture of the AS and CSK extracts could be used to develop functional foods and serve as raw materials for the development of therapeutics against Alzheimer's disease.

• The Journal of the Korea Contents Association
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• v.11 no.7
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• pp.179-191
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• 2011

This study aims to elucidate the relationship between the characteristics of adult learners and flow in cyber-class along with relationships among flow, stress, and problem-solving ability. The research subjects were 1044 enrolled students at Cyber University located in Seoul through voluntary on-line questionnaire. The analysis is following: The components of flow on cyber-class including enjoyment, engagement, focused attention, and time-distortion show the significant difference upon the characteristics of adult learners such as school grade, age, marital status, and number of registered classes. In addition, the flow on cyber-class has the negative relationship with stress and the positive relationship with problem-solving ability. To improve the level of flow on cyber-class, it is important to develop the new on-line class and class materials with the consideration of characteristics and diverse backgrounds of adult learners. The incorporation of various interactive evaluation can also improve the flow level of adult learners in cyber class. Finally, the learning counselling service might be essential for adult learners to experience flow on cyber-class.

• Journal of Ginseng Research
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• v.43 no.4
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• pp.499-507
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• 2019

Background: Ginsenoside Rb1 (Rb1), a dominant component from the extract of Panax ginseng root, exhibits neuroprotective functions in many neurological diseases. This study was intended to investigate whether Rb1 can attenuate cisplatin-induced memory impairments and explore the potential mechanisms. Methods: Cisplatin was injected intraperitoneally with a dose of 5 mg/kg/wk, and Rb1 was administered in drinking water at the dose of 2 mg/kg/d to rats for 5 consecutive wk. The novel objects recognition task and Morris water maze were used to detect the memory of rats. Nissl staining was used to examine the neuron numbers in the hippocampus. The activities of superoxide dismutase, glutathione peroxidase, cholineacetyltransferase, acetylcholinesterase, and the levels of malondialdehyde, reactive oxygen species, acetylcholine, tumor necrosis factor-${\alpha}$, interleukin-$1{\beta}$, and interleukin-10 were measured by ELISA to assay the oxidative stress, cholinergic function, and neuroinflammation in the hippocampus. Results: Rb1 administration effectively ameliorates the memory impairments caused by cisplatin in both novel objects recognition task and Morris water maze task. Rb1 also attenuates the neuronal loss induced by cisplatin in the different regions (CA1, CA3, and dentate gyrus) of the hippocampus. Meanwhile, Rb1 is able to rescue the cholinergic neuron function, inhibit the oxidative stress and neuroinflammation in cisplatin-induced rat brain. Conclusion: Rb1 rescues the cisplatin-induced memory impairment via restoring the neuronal loss by reducing oxidative stress and neuroinflammation and recovering the cholinergic neuron functions.

• Nutrition Research and Practice
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• v.16 no.2
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• pp.173-193
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• 2022

BACKGROUND/OBJECTIVES: Alzheimer's disease (AD) is one of the most representative neurodegenerative disease mainly caused by the excessive production of amyloid beta (Aβ). Several studies on the antioxidant activity and protective effects of Populus tomentiglandulosa (PT) against cerebral ischemia-induced neuronal damage have been reported. Based on this background, the present study investigated the protective effects of PT against cognitive impairment in AD. MATERIALS/METHODS: We orally administered PT (50 and 100 mg/kg/day) for 14 days in an Aβ_25-35-induced mouse model and conducted behavioral experiments to test cognitive ability. In addition, we evaluated the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum and measured the production of lipid peroxide, nitric oxide (NO), and reactive oxygen species (ROS) in tissues. RESULTS: PT treatment improved the space perceptive ability in the T-maze test, object cognitive ability in the novel object recognition test, and spatial learning/long-term memory in the Morris water-maze test. Moreover, the levels of AST and ALT were not significantly different among the groups, indicating that PT did not show liver toxicity. Furthermore, administration of PT significantly inhibited the production of lipid peroxide, NO, and ROS in the brain, liver, and kidney, suggesting that PT protected against oxidative stress. CONCLUSIONS: Our study demonstrated that administration of PT improved Aβ_25-35-induced cognitive impairment by regulating oxidative stress. Therefore, we propose that PT could be used as a natural agent for AD improvement.

• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.1-11
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• 2021

The purpose of this study was to analyze the trends and characteristics of 'stress urinary incontinence' research through word frequency analysis, and their relationships were modeled using word embedding. Abstract data of 9,868 papers containing abstracts in PubMed's MEDLINE were extracted using a Python program. Then, through frequency analysis, 10 keywords were selected according to the high frequency. The similarity of words related to keywords was analyzed by Word2Vec machine learning algorithm. The locations and distances of words were visualized using the t-SNE technique, and the groups were classified and analyzed. The number of studies related to stress urinary incontinence has increased rapidly since the 1980s. The keywords used most frequently in the abstract of the paper were 'woman', 'urethra', and 'surgery'. Through Word2Vec modeling, words such as 'female', 'urge', and 'symptom' were among the words that showed the highest relevance to the keywords in the study on stress urinary incontinence. In addition, through the t-SNE technique, keywords and related words could be classified into three groups focusing on symptoms, anatomical characteristics, and surgical interventions of stress urinary incontinence. This study is the first to examine trends in stress urinary incontinence-related studies using the keyword frequency analysis and word embedding of the abstract. The results of this study can be used as a basis for future researchers to select the subject and direction of the research field related to stress urinary incontinence.

• The Journal of Internal Korean Medicine
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• v.27 no.1
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• pp.253-264
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• 2006

Object: This research investigated effects of Jujadokseo-hwan on mice with Alzheimer's Disease induced by $amyloid-{\beta}$. According to Dongyibogam, Jujadokseo-hwan can cure amnesia. Amyloid-B is believed to induce oxidative stress and inflammation in the brain, postulated to play important roles in the pathogenesis of Alzheimer's disease. In this way $Amyloid-{\beta}$ induces Alzheimer's Disease. Methods : In order to make an efficient prescription and cope with dementia, learning and memory functions of mice were tested on passive avoidance test and V-maze task. $NF-{\kappa}B$ were measured from protein derived from the brain. RT-PCR was done for !gene analysis. Primers were protein kinase Band $NGF-{\alpha}$. Results : 1. Jujadokseo-hwan was effective for memory capacity on passive avoidance test. but noneffective for spatial memory capacity and locomotor activity on Y -maze task. 2. The measurement of $NF-{\kappa}B$ showed upward tendancies and the result of RT-PCR showed up-regulation when given Jujadokseo-hwan by mouth. Conclusion: Results suggest that Jujadokseo-hwan is effective on mice with Alzheimer's Disease induced by $amyloid-{\beta}$.

• The Korean Journal of Emergency Medical Services
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• v.8 no.1
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• pp.19-32
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• 2004

This study was conducted to identify an initial fire station experience of EMT students, so to better understand their' practice experience in fire station. The subjects were 28 EMT students of C department of Emergency Medical technology in C city, who were demonstrating at the fire station in C city. This study was approached by phenomenological method, collected data were analyzed by Colaizzi's method, the results were as a follows. From the protocol, 201 significant statements were organized into 93 formulated meanings. From the formulated meanings, 30 themes were identified, organized into 16 theme clusters, and then 7 categories. EMT students got experienced 'tension' in resulting from new training situation and at the field practice, 'comport and gratitude', in feeling of identity and a bond sympathy with senior EMT, in training environment and heartfelt care, 'stress' from lack of knowledge and skill, difficulties in field practice for 24 hours, in dealing with making interpersonal relationship with patient and staffs and from the insufficiency of instruction, 'confidence feeling' from the participation of field treatment, in improving of learning, in self-esteem of EMT job, 'confusing feeling' of conflict of the path in work, 'disappointment and doubt' by the discrepancy between learning and actuality, and disappointment of actuality, 'feeling of lack' based on the passive attitude. The results of this study are to use as basic data for students attending fire station experience for the first time.