• Journal of the Korean Geotechnical Society
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• v.24 no.4
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• pp.37-46
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• 2008

Application of resilient modulus, representing mechanical behavior of pavement materials, has become general concept for pavement design, analysis and maintenance after '86 AASHTO selected it as a basic input property of subgrade. It is known that resilient modulus of domestic subgrade soil is affected greatly by material factors, such as water content and dry weight unit, and stress components, such as deviatoric stress and confining stress, while effects of loading frequency and loading repeat were regarded negligible. If design based on resilient modulus is to be successfully implemented, design input variables of relevant models should be able to reflect local conditions. In this study, generalized mechanical model for subgrade is proposed. Model parameters are estimated from test results. Verification of the model was performed through finite element analysis using the proposed model, which showed good agreement with measured results of pavement deflections.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.5 no.2
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• pp.157-165
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• 2015

The purpose of this study is to analyse literacy of children from multicultural backgrounds, and identify cognitive-linguistic predictors that can affect their literacy. First, the higher-grade students showed better cognitive-linguistic variables in reading and writing performance. Second, it has been noted that the predictor variable of reading in children from multicultural backgrounds was homeostasis in visual form, which is a sub-variable of visual perception. This implies that detained characteristics play an important role in reading prerequisite. Therefore it can be said that it is more important to recognise features and clues about the details than reading familiar words. Furthermore, learning consonants and vowels should come first rather than studying letters at the first stages of learning Korean.

• Journal of Korean Academy of Dental Administration
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• v.11 no.1
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• pp.19-27
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• 2023

This study aimed to investigate the relationship between the experience of incivility in clinical practice and stress coping strategies among students enrolled in the Department of Dental Hygiene with clinical practice experience. The study randomly sampled subjects from a group of 150 dental hygiene students attending the Chungcheong area. Descriptive statistics, t-test, ANOVA, and Pearson's correlation analysis were conducted. The trainees experienced a level of incivility of 1.69, and their level of coping with the resulting stress was 2.58. The study found significant results in terms of gender, clinical practice, and major satisfaction when examining the incivility experienced by trainees based on general characteristics. Among these general characteristics, there were statistically significant differences in the avoidance focus among the sub-domains depending on the grade, number of practicums, and satisfaction with clinical practice. Additionally, the problem-solving focus showed significant results depending on satisfaction with the major. The incivility experienced by trainees showed a positive correlation with avoidance-oriented coping among stress coping strategies (r=.268), social support-seeking coping (r=-.045), and problem-solving-oriented coping (r=-.034) was found to have a negative correlation. If you find yourself in a situation where you encounter incivility, it is believed that developing communication skills and assertiveness training can help you respond more actively instead of passively, which is an avoidance-oriented approach. In addition, it is important to consider that schools and training organizations should collaborate to establish an official reporting system to ensure that any instances of incivility experienced by trainees are not ignored.

• Journal of Korean society of Dental Hygiene
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• v.24 no.2
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• pp.187-195
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• 2024

Objectives: This study aimed to explore ways to improve the level of positive psychological capital of dental hygiene students. After comparing the levels of positive psychological capital, social support, and emotional regulation ability of dental hygiene students and identifying correlations, the sub-factors of social support and emotional regulation ability that affect positive psychological capital were identified. Methods: A survey of 70 questions was conducted targeting 310 dental hygiene students in Gyeonggi-do and Chungcheong-do. The results were subjected to exploratory factor analysis, frequency analysis, t-test, one-way ANOVA, correlation analysis, and multiple regression analysis using the PASW statistics 18.0 program. Results: The level of positive psychological capital was high when students had high grades and perceived positive relationships with professors and peers (p<0.001). Factors highly correlated with positive psychological capital include 'self-emotional regulation ability' among 'emotion regulation abilities' (r=0.665, p<0.001), and 'emotional support related to daily life' recognized 'social support' (r=0.635, p<0.001), followed by 'social support' (r=0.602, p<0.001). Factors affecting positive psychological capital include 'self-emotion recognized ability' (β=0.377, p<0.001), 'quality of professor relationship' (β=0.201, p<0.001), and 'emotion control ability'. Among 'social support', 'emotional support related to daily life' (β=0.201, p=0.003) and 'grades' (β=0.159, p<0.001), and among 'social support', 'social-related support' (β=0.149, p=0.016), followed by 'grade' (β=0.076, p=0.043) were identified. Conclusions: To improve the positive psychological capital of dental hygiene students, efforts should be made to improve self-emotion regulation ability, professor relationships, emotional support related to daily life, and social support.

• Journal of the Health Care and Life Science
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• v.11 no.2
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• pp.271-277
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• 2023

This study targeted 125 prospective early childhood teachers at G University in G Metropolitan City to investigate their perceptions of safety care practices. The collected data were analyzed using One-way ANOVA and Scheffe's post hoc test. As a result of the study, there was a statistically significant difference in the overall awareness of safe care practices of prospective early childhood teachers according to grade. Statistically significant differences were found in the sub-factors 'Life Safety', 'Traffic Safety', 'Violence and Personal Safety', 'Drugs and Cyber Addiction', and 'Disaster Safety'. On the other hand, there was no statistically significant difference in 'occupational safety' and 'first aid'. Through these results, Through these results, we aim to increase safety competency by measuring safety care practices, expand practical training opportunities for prospective early childhood teachers, develop various media, and above all, improve class operation and content related to safety in early childhood teacher training courses. Based on this, we aim to provide basic data to develop a pre-service early childhood teacher education program.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.653-658
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• 2016

Poly(ether-block-amide)(PEBAX$_{(R)}$) resin is a thermoplastic elastomer combining linear chains of hard-rigid polyamide block interspaced soft-flexible polyether block. It was believed that the hard polyamide block provides the mechanical strength and permselectivity, whereas gas transport occurs primarily through the soft polyether block. The objective of this work was to investigate the gas permeation properties of carbon dioxide and methane for PEBAX$^{(R)}$-1657 membrane, and compare with those obtained for other grade of pure PEBAX$^{(R)}$, PEBAX$^{(R)}$-2533 and PEBAX$^{(R)}$ based hybrid membranes. The hybrid membranes based PEBAX$^{(R)}$ were obtained by a sol-gel process using GPTMS ((3-glycidoxypropyl) trimethoxysilane) as the only inorganic precursor. Molecular structure and morphology of membrane were analyzed by $^{29}Si$-NMR, DSC and SEM. PEBAX$_{(R)}$-2533 membrane exhibited higher gas permeability coefficients than PEBAX$^{(R)}$-1657 membrane. This was explained by the increase of chain mobility. In contrast, ideal separation factor of $CO_2/CH_4$ for PEBAX$^{(R)}$-1657 membrane was higher than PEBAX$^{(R)}$-2533 membrane. It was explained by the decrease of diffusion selectivity caused by increase of chain mobility. For PEBAX$^{(R)}$/GPTMS hybrid membrane, gas permeability coefficients were decreased with reaction time. Gas permeability coefficient of $CH_4$ was more significantly decreased than $CO_2$. It can be explained by the reduction of chain mobility caused by the sol-gel process, and strong affinity of PEO segment with $CO_2$. Comparing with pure PEBAX$^{(R)}$-1657 membrane, ideal separation factor of $CO_2/CH_4$ for PEBAX$^{(R)}$/GPTMS hybrid membrane has decreased to 4.5%, and gas permeability coefficient of $CO_2$ has increased 3.5 times.

• Journal of Hydrogen and New Energy
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• v.7 no.1
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• pp.81-92
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• 1996

The Ar/Ar-$H_2$ plasma method was applied to reduce oxides and refine metals of V, Ta and B. In addition, the high temperature chemical reaction in Ar plasma and of the refining reaction in the Ar-(20%)$H_2$ plasma were analyzed. The crude V of 96wt% purity was obtained at the ratio of $C/V_{2}O_{5}=4.50$ by the Ar plasma reduction grade and the maximum reduction was obtained at $C/V_{2}O_{5}=4.50$ due to the $O_{2}$ loss from the thermal decomposition of vanadium oxide. In the Ar-(20%)$H_2$ plasma refining, the metallic V of 99.2wt% was produced at the ratio of $C/V_{2}O_{5}=4.40$. It was considered that a main refining reaction resulted from the chemical reaction between the residual carbon and residual oxygen. The metallic Ta of 99.8wt% was obtained at the ratio of $C/Ta_{2}O_{5}=5.10$ in a Ar plasma reduction and the Oz loss from the thermal decomposition of tantalum pentoxide did not take place. The deoxidation reaction was more significant than the decarburization reaction in the Ar-(20%)$H_2$ plasma refining and the metallic Ta of 99.9wt% was produced within the range of $C/Ta_{2}O_{5}$ ratio of 4.50 to 5.10. The Vickers hardness of Ta in the above mentioned range was about 220Hv due to the decrease in a residual oxygen by the deoxidation reaction. On the other hand, C is no suitable agent for the reduction of $B_{2}O_{3}$ by the Ar and Ar-$H_2$ plasma. But Fe-B-Si alloy was produced with the reduction of $B_{2}O_{3}$ in the melt when Fe, C, $B_{2}O_{3}$, and ferroboron mixtures were melted by the high frequency induction melting.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.4
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• pp.243-249
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• 2019

A barley(Hordeum vulgare L.) cultivar 'Youjin' with hooded spike type having good silage quality was developed at National Institute of Crop Science, RDA in 2016. 'Youjin' showed both high yielding and cold resistance through the preliminary and advanced yield trials(PYT, AYT) from 2012 to 2013. We conducted regional yield trials(RYT) of 'Youjin' in six locations around Korea for three years from 2014 to 2016. It had erect plant type, growth habit of II, the green leaf and hooded awn type. In the paddy field its heading date was April 24 and the maturing date was May 25. Plant height was 99 cm and the number of spikes per ㎡ was 696. It has high rate of leaf blades, resistance to BaYMV(Barley Yellow Mosiac Virus) and good winter hardiness. The average dry matter of Youjin was about 17.2 MT ha^-1 in the field. And feed quality of 'Youjin' was 10.6% of crude protein content, 24.8% of ADF(Acid Detergent Fiber), 43.5 % of NDF(Neutral Detergent Fiber), 69.1% of TDN(Total Digestible Nutrients). And also 'Youjin' had grade I of silage quality.

• Communications of Mathematical Education
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• v.24 no.2
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• pp.415-444
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• 2010

The purpose of this study is to provide information that will help understand unique characteristics of mathematically gifted students and that can be utilized for special programs for mathematically gifted students, by investigating difference and relationship between attribution styles and attitude toward mathematics of mathematically gifted students and those of regular students. For that purpose, 202 mathematically gifted students and 415 regular students in 5th and 6th grades at elementary schools were surveyed in terms of attribution styles and attitude toward mathematics, and the result of the study is as follows. First, as for attribution styles, there was no difference between gifted students and regular students in terms of grade and gender, but there was significant difference in sub factors because of giftedness. Second, there was not significant difference between grades. but there was significant difference in sub factors between genders. Mathematically gifted students were more positive than regular students in every sub factor excepting gender role conformity, and especially they showed higher confidence and motivation. Third, according to the result of correlation analysis, there was significant static correlation between inner tendencies and attitude toward mathematics with both groups. The gifted group showed higher correlation between attribution of effort and attitude toward mathematics and inner tendencies and confidence than the regular group. The gifted group showed higher correlation in sub factors, and especially there was high static correlation between attribution of talent and confidence, and attribution of effort and motivation. Fourth, according to the result of multiple regression analysis, inner tendencies showed significant relation to attitude toward mathematics with both groups, and especially the influence of attribution of effort was high. Both attribution of effort and attribution of talent were higher in the gifted group than the regular group, and attribution of effort had a major influence on practicality and attribution of talent had a major influence on confidence.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.469-484
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• 2021

Rock mass classification results have a great influence on construction schedule and budget as well as tunnel stability in tunnel design. A total of 3,526 tunnels have been constructed in Korea and the associated techniques in tunnel design and construction have been continuously developed, however, not many studies have been performed on how to assess rock mass quality and grade more accurately. Thus, numerous cases show big differences in the results according to inspectors' experience and judgement. Hence, this study aims to suggest a more reliable rock mass classification (RMR) model using machine learning algorithms, which is surging in availability, through the analyses based on various rock and rock mass information collected from boring investigations. For this, 11 learning parameters (depth, rock type, RQD, electrical resistivity, UCS, V_p, V_s, Young's modulus, unit weight, Poisson's ratio, RMR) from 13 local tunnel cases were selected, 337 learning data sets as well as 60 test data sets were prepared, and 6 machine learning algorithms (DT, SVM, ANN, PCA & ANN, RF, XGBoost) were tested for various hyperparameters for each algorithm. The results show that the mean absolute errors in RMR value from five algorithms except Decision Tree were less than 8 and a Support Vector Machine model is the best model. The applicability of the model, established through this study, was confirmed and this prediction model can be applied for more reliable rock mass classification when additional various data is continuously cumulated.